WorldWideScience

Sample records for central helium liquefier

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

    Science.gov (United States)

    Wang, Chao; Oviedo, Abner

    2012-06-01

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

  2. Multi-objective Optimization on Helium Liquefier Using Genetic Algorithm

    Science.gov (United States)

    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.

  3. Capacity enhancement of indigenous expansion engine based helium liquefier

    Science.gov (United States)

    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.

  4. Multipurpose closed-cycle cryocooler for liquefying hydrogen, helium-4 or helium-3

    Science.gov (United States)

    Winter, Calvin

    1990-08-01

    A cryogenic refrigerator utilizing helium-4 gas in closed-cycle Gifford-McMahon and Joule-Thomson cooling loops was built and achieves continuous operating temperatures of 2.8R. The object cooled is a thin walled (0.1mm) seamless electroformed nickel target sample cell with a volume of 160m1. Room temperature hydrogen, helium-4 or helium-3 gas, supplied at a pressure slightly above atmospheric, is liquefied by the cryocooler and fills the cell. Unusual features include: horizontal operation; a long narrow extension on the vacuum shroud (900mm long, 76mm diameter) and special valves to select an operating temperature appropriate to the sample gas and maximize the cooling power available at that temperature.

  5. Study of a multi-strategy controller on a helium liquefier

    Science.gov (United States)

    Lei, L. L.; Meng, Y. R.; Peng, N.; Xiong, L. Y.; Tang, J. C.; Dong, B.; Liu, L. Q.

    2017-02-01

    Helium liquefier is widely used in the fields of superconducting, nuclear fusion energy and high-energy physics. However, the present PID controlling system of the liquefier is not able to keep the compressor suction pressure, outlet pressure and turbine inlet pressure all in the expected range at the same time. Thus, a multi-strategy controller for a helium liquefier is proposed in this paper. A dynamic simulation model of this liquefier is also developed and shown. To study the control effect, an operation process including cool-down, steady-state and pulse of heat is described. The simulation result of this process is presented and compared with the result of the present PID controlling system.

  6. Laptop-assisted Helium Liquefier: software for tailored monitoring and control

    CERN Document Server

    Marceddu, Marco

    2016-01-01

    Computer running human machine interfaces are fast supplanting conventional hardware dedicated to monitoring and supervising tasks. This kind of approach was successfully employed to develop a new monitoring and control software, running on a conventional laptop computer, for a small size helium liquefier. This software was realized with a SCADA development package and hallowed to manage all the liquefier functionalities. Being conceived as an open structure suitable for further upgrades, this liquefier HMI can be tailored on demand to satisfy specific needs of the end-user, even if not provided by the original manufacturer project.

  7. The optimization on flow scheme of helium liquefier with genetic algorithm

    Science.gov (United States)

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

    2017-01-01

    There are several ways to organize the flow scheme of the helium liquefiers, such as arranging the expanders in parallel (reverse Brayton stage) or in series (modified Brayton stages). In this paper, the inlet mass flow and temperatures of expanders in Collins cycle are optimized using genetic algorithm (GA). Results show that maximum liquefaction rate can be obtained when the system is working at the optimal parameters. However, the reliability of the system is not well due to high wheel speed of the first turbine. Study shows that the scheme in which expanders are arranged in series with heat exchangers between them has higher operation reliability but lower plant efficiency when working at the same situation. Considering both liquefaction rate and system stability, another flow scheme is put forward hoping to solve the dilemma. The three configurations are compared from different aspects, they are respectively economic cost, heat exchanger size, system reliability and exergy efficiency. In addition, the effect of heat capacity ratio on heat transfer efficiency is discussed. A conclusion of choosing liquefier configuration is given in the end, which is meaningful for the optimal design of helium liquefier.

  8. Enhancement of the Liquefaction Rate in Small-Scale Helium Liquefiers Working Near and Above the Critical Point

    Science.gov (United States)

    Rillo, C.; Gabal, M.; Lozano, M. P.; Sesé, J.; Spagna, S.; Diederichs, J.; Sager, R.; Chialvo, C.; Terry, J.; Rayner, G.; Warburton, R.; Reineman, R.

    2015-05-01

    Low-temperature research laboratories with typical liquid-helium consumption of the order of tens of liters per day have greatly benefited from the recent development of small-scale liquefiers. In general, these liquefiers are based on Gifford-McMahon or pulse-tube closed-cycle refrigerators with a nominal cooling power ranging from 1 to 1.5 W at 4.2 K. The liquefaction rate for these cryocooler-based liquefiers depends on the pressure at which the helium is liquefied, although the final user conditions of the produced liquid helium are always atmospheric pressure and boiling temperature (e.g., 4.2 K at 100 kPa). Here, we show a systematic study on this effect, in which an enhancement in excess of 70% in liquefaction rate is found experimentally for pressures near and above the critical point of helium (220 kPa). We propose that the underlying mechanism for the liquefaction enhancement is based on the increase in cryocooler cooling power with temperature and the decrease of the helium enthalpy with pressure.

  9. Commissioning and Operational Experience with 1 kW Class Helium Refrigerator/Liquefier for SST-1

    Science.gov (United States)

    Dhard, C. P.; Sarkar, B.; Misra, Ruchi; Sahu, A. K.; Tanna, V. L.; Tank, J.; Panchal, P.; Patel, J. C.; Phadke, G. D.; Saxena, Y. C.

    2004-06-01

    The helium refrigerator/liquefier (R/L) for the Steady State Super conducting Tokamak (SST-1) has been developed with very stringent specifications for the different operational modes. The total refrigeration capacity is 650 W at 4.5 K and liquefaction capacity of 200 l/h. A cold circulation pump is used for the forced flow cooling of 300 g/s supercritical helium (SHe) for the magnet system (SCMS). The R/L has been designed also to absorb a 200 W transient heat load of the SCMS. The plant consists of a compressor station, oil removal system, on-line purifier, Main Control Dewar (MCD) with associated heat exchangers, cold circulation pump and warm gas management system. An Integrated Flow Control and Distribution System (IFDCS) has been designed, fabricated and installed for distribution of SHe in the toroidal and poloidal field coils as well as liquid helium for cooling of 10 pairs of current leads. A SCADA based control system has been designed using PLC for R/L as well as IFDCS. The R/L has been commissioned and required parameters were achieved confirming to the process. All the test results and commissioning experiences are discussed in this paper.

  10. Numerical studies on sizing/ rating of plate fin heat exchangers for a modified Claude cycle based helium liquefier/ refrigerator

    Science.gov (United States)

    Goyal, M.; Chakravarty, A.; Atrey, M. D.

    2017-02-01

    Performance of modern helium refrigeration/ liquefaction systems depends significantly on the effectiveness of heat exchangers. Generally, compact plate fin heat exchangers (PFHE) having very high effectiveness (>0.95) are used in such systems. Apart from basic fluid film resistances, various secondary parameters influence the sizing/ rating of these heat exchangers. In the present paper, sizing calculations are performed, using in-house developed numerical models/ codes, for a set of high effectiveness PFHE for a modified Claude cycle based helium liquefier/ refrigerator operating in the refrigeration mode without liquid nitrogen (LN2) pre-cooling. The combined effects of secondary parameters like axial heat conduction through the heat exchanger metal matrix, parasitic heat in-leak from surroundings and variation in the fluid/ metal properties are taken care of in the sizing calculation. Numerical studies are carried out to predict the off-design performance of the PFHEs in the refrigeration mode with LN2 pre-cooling. Iterative process cycle calculations are also carried out to obtain the inlet/ exit state points of the heat exchangers.

  11. The multipurpose helium refrigerators/liquefiers for the new CERN experimental area

    CERN Document Server

    Eber, N; Kurtcuoglu, K; Senn, A

    1979-01-01

    The helium plants described have a nominal capacity of 100 liters/hour or 400 Watts at 4.4K and can also be operated in mixed duty over the whole performance range. The plants feature oilfree labyrinth-piston compressors and turboexpanders with self-supporting gas bearings plus magnetic auxiliary bearings. The greatest peculiarity of the new plants is the first time combined use of cold and warm ejectors. (1 refs).

  12. Development of a Measurement and Control System for a 40l/h Helium Liquefier based on Siemens PLC S7-300

    Science.gov (United States)

    Li, J.; Liu, L. Q.; Xu, X. D.; Liu, T.; Li, Q.; Hu, Z. J.; Wang, B. M.; Xiong, L. Y.; Dong, B.; Yan, T.

    A 40l/h Helium Liquefier has been commissioned by the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. A measurement and control system based on Siemens PLC S7-300 for this Helium Liquefier is developed. Proper sensors are selected, for example, three types of transmitters are adopted respectively according to detailed temperature measurement requirements. Siemens S7-300 PLC CPU315-2PN/DP operates as a master station and three sets of ET200 M DP remote expand I/O operate asslave stations. Profibus-DP field communication is used between the master station and the slave stations. The upper computer HMI(Human Machine Interface) is compiled using Siemens configuration software WinCC V7.0. The upper computer communicates with PLC by means of industrial Ethernet. A specific control logic for this Helium Liquefier is developed. The control of the suction and discharge pressures of the compressor and the control of the turbo-expanders loop are being discussed in this paper. Following the commissioning phase, the outlet temperature of the second stage turbine has reached 8.6K and the temperature before the throttle valve has reached 13.1K.

  13. Helium isotopes in ferromanganese crusts from the central Pacific Ocean

    Science.gov (United States)

    Basu, S.; Stuart, F.M.; Klemm, V.; Korschinek, G.; Knie, K.; Hein, J.R.

    2006-01-01

    Helium isotopes have been measured in samples of two ferromanganese crusts (VA13/2 and CD29-2) from the central Pacific Ocean. With the exception of the deepest part of crust CD29-2 the data can be explained by a mixture of implanted solar- and galactic cosmic ray-produced (GCR) He, in extraterrestrial grains, and radiogenic He in wind-borne continental dust grains. 4He concentrations are invariant and require retention of less than 12% of the in situ He produced since crust formation. Loss has occurred by recoil and diffusion. High 4He in CD29-2 samples older than 42 Ma are correlated with phosphatization and can be explained by retention of up to 12% of the in situ-produced 4He. 3He/4He of VA13/2 samples varies from 18.5 to 1852 Ra due almost entirely to variation in the extraterrestrial He contribution. The highest 3He/4He is comparable to the highest values measured in interplanetary dust particles (IDPs) and micrometeorites (MMs). Helium concentrations are orders of magnitude lower than in oceanic sediments reflecting the low trapping efficiency for in-falling terrestrial and extraterrestrial grains of Fe-Mn crusts. The extraterrestrial 3He concentration of the crusts rules out whole, undegassed 4–40 μm diameter IDPs as the host. Instead it requires that the extraterrestrial He inventory is carried by numerous particles with significantly lower He concentrations, and occasional high concentration GCR-He-bearing particles.

  14. Thermoacoustic natural gas liquefier

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.W. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

    1997-05-01

    Cryenco and Los Alamos are collaborating to develop a natural-gas-powered natural-gas liquefier that will have no moving parts and require no electrical power. It will have useful efficiency, remarkable reliability, and low cost. The liquefaction of natural gas, which occurs at only 115 Kelvin at atmospheric pressure, has previously required rather sophisticated refrigeration machinery. The 1990 invention of the thermoacoustically driven orifice pulse-tube refrigerator (TA-DOPTR) provides cryogenic refrigeration with no moving parts for the first time. In short, this invention uses acoustic phenomena to produce refrigeration from heat. The required apparatus consists of nothing more than helium-filled heat exchangers and pipes, made of common materials, without exacting tolerances. In the Cryenco-Los Alamos collaboration, the authors are developing a version of this invention suitable for use in the natural-gas industry. The project is known as acoustic liquefier for short. The present program plans call for a two-phase development. Phase 1, with capacity of 500 gallon per day (i.e., approximately 40,000 scfd, requiring a refrigeration power of about 7 kW), is large enough to illuminate all the issues of large-scale acoustic liquefaction without undue cost, and to demonstrate the liquefaction of 60--70% of input gas, while burning 30--40%. Phase 2 will target versions of approximately 10{sup 6} scfd = 10,000 gallon per day capacity. In parallel with both, they continue fundamental research on the technology, directed toward increased efficiency, to build scientific foundations and a patent portfolio for future acoustic liquefiers.

  15. Assessment and study of existing concepts and methods of cryogenic refrigeration for superconducting transmission cables. Progress report, 1 September 1975--31 October 1975. [Operation of helium liquefiers

    Energy Technology Data Exchange (ETDEWEB)

    Kadi, F J; Longsworth, R C

    1975-01-01

    Progress made in a six task program on methods for cryogenic refrigeration for superconducting transmission cables is reported. The current report period included a review of equipment versus requirements, development of an optimization criteria, and evaluation of component reliability and efficiency. The results and findings of the helium refrigerator user visits, system and component manufacturers responses to questionnaires, telephone calls and visits, and the information obtained from a review of APCI standard N/sub 2/ plant experience are presented.

  16. Active Magnetic Regenerative Liquefier

    Energy Technology Data Exchange (ETDEWEB)

    Barclay, John A. [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Oseen-Send, Kathryn [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Ferguson, Luke [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Pouresfandiary, Jamshid [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Cousins, Anand [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Ralph, Heather [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Hampto, Tom [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States)

    2016-01-12

    This final report for the DOE Project entitled Active Magnetic Regenerative Liquefier (AMRL) funded under Grant DE-FG36-08GO18064 to Heracles Energy Corporation d.b.a. Prometheus Energy (Heracles/Prometheus) describes an active magnetic regenerative refrigerator (AMRR) prototype designed and built during the period from July 2008 through May 2011. The primary goal of this project was to make significant technical advances toward highly efficient liquefaction of hydrogen. Conventional hydrogen liquefiers at any scale have a maximum FOM of ~0.35 due primarily to the intrinsic difficulty of rapid, efficient compression of either hydrogen or helium working gases. Numerical simulation modeling of high performance AMRL designs indicates certain designs have promise to increase thermodynamic efficiency from a FOM of ~0.35 toward ~0.5 to ~0.6. The technical approach was the use of solid magnetic working refrigerants cycled in and out of high magnetic fields to build an efficient active regenerative magnetic refrigeration module providing cooling power for AMRL. A single-stage reciprocating AMRR with a design temperature span from ~290 K to ~120 K was built and tested with dual magnetic regenerators moving in and out of the conductively-cooled superconducting magnet subsystem. The heat transfer fluid (helium) was coupled to the process stream (refrigeration/liquefaction load) via high performance heat exchangers. In order to maximize AMRR efficiency a helium bypass loop with adjustable flow was incorporated in the design because the thermal mass of magnetic refrigerants is higher in low magnetic field than in high magnetic field. Heracles/Prometheus designed experiments to measure AMRR performance under a variety of different operational parameters such as cycle frequency, magnetic field strength, heat transfer fluid flow rate, amount of bypass flow of the heat transfer fluid while measuring work input, temperature span, cooling capability as a function of cold temperature

  17. Helium-Hydrogen Recovery System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Immense quantities of expensive liquefied helium are required at Stennis and Kennedy Space Centers for pre-cooling rocket engine propellant systems prior to filling...

  18. Helium liquefaction with a 4 K pulse tube cryocooler

    Science.gov (United States)

    Wang, Chao

    2001-07-01

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

  19. Magnetic liquefier for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-31

    This document summarizes work done at the Astronautics Technology Center of the Astronautics Corporation of America (ACA) in Phase 1 of a four phase program leading to the development of a magnetic liquefier for hydrogen. The project involves the design, fabrication, installation, and operation of a hydrogen liquefier providing significantly reduced capital and operating costs, compared to present liquefiers. To achieve this goal, magnetic refrigeration, a recently developed, highly efficient refrigeration technology, will be used for the liquefaction process. Phase 1 project tasks included liquefier conceptual design and analysis, preliminary design of promising configurations, design selection, and detailed design of the selected design. Fabrication drawings and vendor specifications for the selected design were completed during detailed design. The design of a subscale, demonstration magnetic hydrogen liquefier represents a significant advance in liquefaction technology. The cost reductions that can be realized in hydrogen liquefaction in both the subscale and, more importantly, in the full-scale device are expected to have considerable impact on the use of liquid hydrogen in transportation, chemical, and electronic industries. The benefits to the nation from this technological advance will continue to have importance well into the 21st century.

  20. Residual oil aerosol measurements on refrigerators and liquefiers

    Science.gov (United States)

    Pflueckhahn, D.; Anders, W.; Hellwig, A.; Knobloch, J.; Rotterdam, S.

    2014-01-01

    The purity of the process gas is essential for the reliability of refrigerators and liquefiers. Filtration and adsorption of impurities like water, nitrogen, and oil result in a major effort, cost, and maintenance in the helium process. Expensive impurity monitors for moisture, nitrogen, and hydrocarbon contents are required to identify filter failures and leakage immediately during the operation. While water and nitrogen contaminants can be detected reliably, the measurement of oil aerosols at the ppb-level is challenging. We present a novel diagnostic oil aerosol measurement system able to measure particles in the sub-μm range. This unit enabled us to evaluate and improve the oil separation system on a LINDE TCF 50 helium liquefier.

  1. Active Gas Regenerative Liquefier Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We offer a novel liquefier that has the potential to simultaneously increase thermodynamic efficiency and significantly reduce complexity. The ?active gas...

  2. Carbon dioxide and helium dissolved gases in groundwater at central Tenerife Island, Canary Islands: chemical and isotopic characterization

    Science.gov (United States)

    Marrero-Diaz, Rayco; López, Dina; Perez, Nemesio M.; Custodio, Emilio; Sumino, Hirochika; Melián, Gladys V.; Padrón, Eleazar; Hernandez, Pedro A.; Calvo, David; Barrancos, José; Padilla, Germán; Sortino, Francesco

    2015-10-01

    Seismic-volcanic unrest was detected between 2004 and 2005 in the central and northwest zones of Tenerife Island (Canary Islands, Spain). With the aim of strengthening the program of geochemical and seismic-volcanic surveillance, a study of the origin, characteristics, and spatial distribution of dissolved carbon dioxide (CO2) and helium (He) gases in the volcanic aquifer of central Tenerife Island and around Teide volcano was carried out. This work also improves the hydrogeological and hydrogeochemical conceptual model of groundwater flow. Dissolved CO2 concentrations in sampled groundwater are several orders of magnitude higher than that of air-saturated water (ASW) suggesting a significant contribution of non-atmospheric CO2, mainly magmatic, confirmed through measurement of isotopic compositions (δ13CTDIC) and total dissolved inorganic carbon (TDIC) concentrations. A vertical stratification of dissolved CO2 and δ13CTDIC values was observed in the volcanic aquifer at the eastern region of Las Cañadas Caldera. Stratification seems to be controlled by both degree of magmatic CO2-water interaction and CO2 degassing and the original δ13Cco2(g) isotopic composition. The highest dissolved helium (4He) concentrations in groundwater seem to be related to radiogenic contributions resulting from water-rock interactions, and increase with residence time, instead of with endogenous magmatic inputs. Isotopic systematics show that the dissolved gases in groundwater of central Tenerife are variable mixtures of CO2-3He-rich fluids of volcanic-hydrothermal origin with both organic and atmospheric components. The results suggest that the eastern area of Las Cañadas Caldera, the South Volcanic Ridge, and the Teide summit cone are the areas most affected by degassing of the volcanic-hydrothermal system, and they are therefore the most suitable zones for future geochemical monitoring.

  3. Thermoacoustic natural gas liquefier

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.W. [Los Alamos National Lab., NM (United States)

    1995-06-01

    In collaboration with Cryenco Inc. and NIST-Boulder, we intend to develop a natural gas-powered natural-gas liquefier which has absolutely no moving parts and requires no electrical power. It will have high efficiency, remarkable reliability, and low cost. Progress on the liquefier to be constructed at Cryenco continues satisfactorily. The thermoacoustic driver is still ahead of the pulse tube refrigerator, because of NIST`s schedule. We completed the thermoacoustics design in the fall of 1994, with Los Alamos providing physics input and checks of all aspects, and Cryenco providing engineering to ASME code, drafting, etc. Completion of this design represents a significant amount of work, especially in view of the many unexpected problems encountered. Meanwhile, Cryenco and NIST have almost completed the design of the pulse tube refrigerator. At Los Alamos, we have assembled a half-size scale model of the thermoacoustic portion of the 500 gal/day TANGL. This scale model will enable easy experimentation in harmonic suppression techniques, new stack geometries, new heat-exchanger geometries, resonator coiling, and other areas. As of March 1995, the scale model is complete and we are performing routine debugging tests and modifications.

  4. Liquefied Natural Gas Transfer

    Science.gov (United States)

    1980-01-01

    Chicago Bridge & Iron Company's tanks and associated piping are parts of system for transferring liquefied natural gas from ship to shore and storing it. LNG is a "cryogenic" fluid meaning that it must be contained and transferred at very low temperatures, about 260 degrees below Fahrenheit. Before the LNG can be pumped from the ship to the storage tanks, the two foot diameter transfer pipes must be cooled in order to avoid difficulties associated with sharp differences of temperature between the supercold fluid and relatively warm pipes. Cooldown is accomplished by sending small steady flow of the cryogenic substance through the pipeline; the rate of flow must be precisely controlled or the transfer line will be subjected to undesirable thermal stress.

  5. Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan, central Chinese Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus < 0.03 Ra, where Ra is the 3He/4He ratio normalized to the atmospheric value of 1.4×10-6). The interplanetary dust particles (IDPs), which are very rich in 3He, continuously bombard the Earth and can accumulate in deposits. IDPs sedimentation rate changes can significantly influence 3He concentration in the Earth surface sediments. Since IDPs are not easy to detect in terrestrial deposits, measuring helium isotopes is a helpful approach to examine changes in IDPs. Helium concentration and helium isotopic composition magnetic substances and the quartz particles were examined for helium concentration and helium isotopic ratio. Results show that the 3He/4He ratio and the 3He concentrations of the magnetic substances are clearly higher than those of the bulk samples and the quartz particles, and, the 3He/4He ratio of the extracted magnetic substances is also higher than that of the average level of the Earth's crust. The higher helium content in the magnetic fractions can be explained by an influx of IDPs.

  6. Education in Helium Refrigeration

    Science.gov (United States)

    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.

  7. Development of helium refrigeration/ liquefaction system at BARC, India

    Science.gov (United States)

    Ansari, N. A.; Goyal, M.; Chakravarty, A.; Menon, Rajendran S.; Jadhav, M.; Rane Nair, T., Sr.; Kumar, J.; Kumar, N.; Bharti, SK; Chakravarty, Abhilash; Jain, A.; Joemon, V.

    2017-02-01

    An experimental helium refrigerator/liquefier, using ultra high speed cryogenic turboexpanders, is designed and developed at Cryo-Technology Division, BARC. The developed system is based on the modified Claude cycle. The developed system is presently fully functional consisting of process compressor with gas management system, coldbox, helium receiver Dewar, tri-axial transfer line and helium recovery system. Extended trial runs are conducted to evaluate the performance of the developed system. During these trials, liquefaction rate of around 32 l/hr and refrigeration capacity of around 190W is achieved. The paper addresses design, development and commissioning aspects of the developed helium liquefier along with results of performance evaluation trial runs.

  8. Liquid helium

    CERN Document Server

    Atkins, K R

    1959-01-01

    Originally published in 1959 as part of the Cambridge Monographs on Physics series, this book addresses liquid helium from the dual perspectives of statistical mechanics and hydrodynamics. Atkins looks at both Helium Three and Helium Four, as well as the properties of a combination of the two isotopes. This book will be of value to anyone with an interest in the history of science and the study of one of the universe's most fundamental elements.

  9. Experimental investigation and optimization of small-scale helium liquefaction with multi-cryocoolers

    Science.gov (United States)

    Xu, Dong; Gong, Linghui; Li, Laifeng; Xu, Xiangdong; Liu, Huiming; Huang, Rongjin

    2015-07-01

    Small-scale helium liquefiers using regenerative cryocoolers with cooling power up to 1.5 W at 4.2 K could be used to re-liquefy evaporated helium gas of small- and medium-sized cryogenic devices such as MEG and PPMS. A serial-parallel-path helium liquefier with a liquefaction rate of 83 Litres per day (L/d) using five 4 K G-M cryocoolers is developed, and has been applied to the Wuhan National High Magnetic Field Center (WHMFC) in China. Different from parallel-path helium liquefier, the helium gas is effectively, stepwise precooled by heat exchangers on multi-cold flanges, and thus the additional purifier and precooling coil heat exchangers on the thinner part of the cold head cylinder containing the 2nd stage displacer could be removed to simplify the construction. Through theoretical calculation and conclusive analysis, an optimum configuration is proposed and makes a reference to the design of serial-parallel-path helium liquefier with multi-cryocoolers.

  10. Helium cryogenics

    CERN Document Server

    Van Sciver, Steven W

    2012-01-01

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

  11. A self-circulation helium liquefaction system with five 4 K G-M cryocoolers

    Science.gov (United States)

    Xu, Dong; Gong, Linghui; Li, Laifeng; Xu, Xiangdong; Xie, Zuqi; Zhao, Hongwei; Guo, Xiaohong

    2011-06-01

    A self-circulation helium liquefaction system (SCHLS) with five 4 K G-M cryocoolers is developed to supply liquid helium (LHe) for SECRAL (a superconducting ECR ion source used in Lanzhou city, China). LHe is vaporized in SECRAL and warmed up to room temperature. SCHLS will re-liquefy the helium gas at a rate of 83.2 L/day under normal atmosphere pressure. With SCHLS, SECRAL system can run online without any interruption of refilling LHe.

  12. Helium-argon isotopic tracing for the Pb-Zn-Ag polymetallic ore deposits in the central-south segment of the Da Hinggan Ling Range

    Institute of Scientific and Technical Information of China (English)

    WANG Baode; NIU Shuyin; SUN Aiqun; HU Huabin; LIU Yaming; GUO Lijun; WANG Shuo

    2008-01-01

    In recent years big strides have been made in the exploration of ores in the central-south segment of the Da Hinggan Ling Range, though some debates still exist on the metallogenesis and sources of ore-forming materials.Pyrite and other sulfides in direct relation to the Pb-Zn-Ag ore deposits were chosen for the He and Ar isotopic analysis of ore-forming fluids, and the first He and Ar isotope data have been obtained from the study region.3He/4He ratios in 14 samples collected from 7 mining districts are 2.17x10-6-12.52×10-6, averaging 6.86×10-6 and their R/Ra ratios are 1.56-9.01 Ra, averaging 4.37 Ra. By projecting the data points onto the 3He-4He concentrations diagram, all the points fall near the mantle helium area. The calculated mantle-source helium ratios are within the range of 19.58%-76.96%, with an average of 49.52%. Argon isotopic characteristics are close to those of mantle source, indicating that the ore-forming material was transport upwards via the multi-stage evolution of mantle plume and concentrated as ores in the favorable loci of mantle branch structures.

  13. Antiprotonic helium

    CERN Multimedia

    Eades, John

    2005-01-01

    An exotic atom in w hich an electron and an antiproton orbit a helium nucleus could reveal if there are any differences between matter and antimatter. The author describes this unusual mirror on the antiworld (5 pages)

  14. Factors Affecting the Resinification of Liquefied Phenolated Wood

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiu-hui; Zhao Guang-jie1; Hu Shi-yu

    2005-01-01

    Wood of Chinese fir and poplar were liquefied in phenol at 150℃ and atmospheric pressure. The liquefied wood were reacted with formaldehyde to synthesize the liquefied wood-based resin. The factors affecting the resinification and the properties of new resin were investigated. The results show that the formaldehyde/liquefied wood molar ratio, reaction temperature, reaction time and sodium hydroxide/liquefied wood molar ratio have important influence on the resin characteristics. With the increase of formaldehyde/liquefied wood molar ratio, the yield of resin increases, and the free phenol content of resins decreases, showing that the resinification of liquefied wood is more complete at higher formaldehyde/liquefied wood molar ratios. The reaction temperature on the viscosity of the liquefied resin has considerable effect; the viscosity of resin increased with increasing reaction temperature,and the amount of liquefied poplar resin increased more quickly than that of liquefied Chinese fir resin. The resinification time also has obvious influence on the viscosity of resin; the viscosity of liquefied poplar resin is more sensitive to resinification time compared with that of liquefied Chinese fir. The amount of sodium hydroxide can improve the water miscibility of liquefied wood resin.The optimum sodium hydroxide/liquefied wood molar ratio for preparation of liquefied wood-based resins exceeds 0.4.

  15. Bibliography on Liquefied Natural Gas (LNG) safety

    Science.gov (United States)

    Ordin, P. M.

    1976-01-01

    Approximately 600 citations concerning safety of liquefied natural gas and liquid methane are presented. Each entry includes the title, author, abstract, source, description of figures, key references, and major descriptors for retrieving the document. An author index is provided as well as an index of descriptors.

  16. Turnkey Helium Purification and Liquefaction Plant for DARWIN, Australia

    Science.gov (United States)

    Lindemann, U.; Boeck, S.; Blum, L.; Kurtcuoglu, K.

    2010-04-01

    The Linde Group, through its Australian subsidiary BOC Limited, has signed an agreement with Darwin LNG Pty Ltd for the supply of feed-gas to Linde's new helium refining and liquefaction facility in Darwin, Australia. Linde Kryotechnik AG, located in Switzerland, has carried out the engineering and fabrication of the equipment for the turn key helium plant. The raw feed gas flow of 20'730 Nm3/h contains up to of 3 mol% helium. The purification process of the feed gas consists of partial condensation of nitrogen in two stages, cryogenic adsorption and finally catalytic oxidation of hydrogen followed by a dryer system. Downstream of the purification the refined helium is liquefied using a modified Bryton process and stored in a 30'000 gal LHe tank. For further distribution and export of the liquid helium there are two stations available for filling of truck trailers and containers. The liquid nitrogen, required for refrigeration capacity to the nitrogen removal stages in the purification process as well as for the pre-cooling of the pure helium in the liquefaction process, is generated on site during the feed gas purification process. The optimized process provides low power consumption, maximum helium recovery and a minimum helium loss.

  17. Proposal of an innovative, high-efficiency, large-scale hydrogen liquefier

    Energy Technology Data Exchange (ETDEWEB)

    Valenti, Gianluca; Macchi, Ennio [Dipartimento di Energia, Politecnico di Milano, P.zza L. da Vinci, 32, 20133 Milano (Italy)

    2008-06-15

    An innovative, efficient and large hydrogen liquefier is described. Innovations lie in the fact that (i) the feed, 10 kg s{sup -1}, is refrigerated in heat exchangers catalytically promoting the ortho-para conversion (ii) down to the low temperature of 20.5 K and at the high pressure of 60 bar at which it is available and (iii) lastly expanded to the storage conditions of 1.5 bar and 20 K through a liquid-phase turbomachine; (iv) refrigeration is via four helium recuperative Joule-Brayton cycles arranged so that the refrigerant follows the cooling curve of hydrogen and the volume flow rates in compression and expansion processes are typical of axial-flow high-efficiency turbomachines; (v) compression is accomplished in 15 intercooled 8-stage devices derived from gas turbine technology. Heat exchangers require specific surfaces comparable to current state-of-the-art liquefiers. Nevertheless, the predicted work of approximately 18 MJ kg{sup -1} is half as much as the requirement of those liquefiers and corresponds to a second-law efficiency of almost 48%. (author)

  18. The Global Market for Liquefied Natural Gas

    OpenAIRE

    David Jacobs

    2011-01-01

    Liquefied natural gas (LNG) provides an economic means to transport natural gas over long distances, bringing production from remote gas reserves to market. A large expansion in global LNG trade is currently under way, and Australia is likely to emerge as the second largest supplier globally in coming years. This article describes the functioning of the global LNG market and outlines Australia's position within the market.

  19. Fuel tank for liquefied natural gas

    Science.gov (United States)

    DeLay, Thomas K. (Inventor)

    2012-01-01

    A storage tank is provided for storing liquefied natural gas on, for example, a motor vehicle such as a bus or truck. The storage tank includes a metal liner vessel encapsulated by a resin-fiber composite layer. A foam insulating layer, including an outer protective layer of epoxy or of a truck liner material, covers the composite layer. A non-conducting protective coating may be painted on the vessel between the composite layer and the vessel so as to inhibit galvanic corrosion.

  20. Risk management of liquefied natural gas installations

    Science.gov (United States)

    Fedor, O. H.; Parsons, W. N.; Coutinho, J. De C.

    1976-01-01

    In connection with the construction of four major liquefied natural gas (LNG) facilities in New York City, the New York City Fire Commissioner has asked NASA for assistance. It was decided that the Kennedy Space Center should develop a risk management system (RMS) for the use of the New York Fire Department (NYFD). The RMS provides for a published set of safety regulations by the NYFD. A description of the RMS is presented as an example of an application of aerospace technology to a civilian sector, namely LNG facilities.

  1. Lightweight Tanks for Storing Liquefied Natural Gas

    Science.gov (United States)

    DeLay, Tom

    2008-01-01

    Single-walled, jacketed aluminum tanks have been conceived for storing liquefied natural gas (LNG) in LNG-fueled motor vehicles. Heretofore, doublewall steel tanks with vacuum between the inner and outer walls have been used for storing LNG. In comparison with the vacuum- insulated steel tanks, the jacketed aluminum tanks weigh less and can be manufactured at lower cost. Costs of using the jacketed aluminum tanks are further reduced in that there is no need for the vacuum pumps heretofore needed to maintain vacuum in the vacuum-insulated tanks.

  2. Liquefied Natural Gas (LNG) dispenser verification device

    Science.gov (United States)

    Xiong, Maotao; Yang, Jie-bin; Zhao, Pu-jun; Yu, Bo; Deng, Wan-quan

    2013-01-01

    The composition of working principle and calibration status of LNG (Liquefied Natural Gas) dispenser in China are introduced. According to the defect of weighing method in the calibration of LNG dispenser, LNG dispenser verification device has been researched. The verification device bases on the master meter method to verify LNG dispenser in the field. The experimental results of the device indicate it has steady performance, high accuracy level and flexible construction, and it reaches the international advanced level. Then LNG dispenser verification device will promote the development of LNG dispenser industry in China and to improve the technical level of LNG dispenser manufacture.

  3. 77 FR 2126 - Pipeline Safety: Implementation of the National Registry of Pipeline and Liquefied Natural Gas...

    Science.gov (United States)

    2012-01-13

    ... Registry of Pipeline and Liquefied Natural Gas Operators AGENCY: Pipeline and Hazardous Materials Safety... registry of pipeline and liquefied natural gas operators. FOR FURTHER INFORMATION CONTACT: Jamerson Pender... 72878), titled: ``Pipeline Safety: Updates to Pipeline and Liquefied Natural Gas Reporting...

  4. 75 FR 53371 - Liquefied Natural Gas Facilities: Obtaining Approval of Alternative Vapor-Gas Dispersion Models

    Science.gov (United States)

    2010-08-31

    ... Pipeline and Hazardous Materials Safety Administration Liquefied Natural Gas Facilities: Obtaining Approval... Safety Administration (PHMSA) issues federal safety standards for siting liquefied natural gas (LNG...) NFPA 59A: Standard for the Production, Storage, and Handling of Liquefied Natural Gas. That...

  5. A Liquefier for Mars Surface Propellant Production

    Science.gov (United States)

    Salerno, Lou J.; Helvensteijn, B. P. M.; Kittel, P.; Arnold, James O. (Technical Monitor)

    1999-01-01

    NASA's planned Mars exploration missions will require that cryogenic propellants be manufactured on the surface. The present scenario calls for oxygen and methane gases to he produced using the carbon dioxide atmosphere plus seed hydrogen brought from Earth. Gases will require liquefaction for both storage on the Martian surface and for use in the ascent vehicle. The planned liquefaction rates range from 12.6 g/hr of oxygen for the 2003 robotic mission to 2500 g/hr for the later human missions. This paper presents the results of a nitrogen liquefaction demonstration using a commercially available cryocooler. The experiment was set up to liquefy nitrogen gas instead of oxygen to limit laboratory safety concerns. A nitrogen gas condensor, attached to the cooler's cold tip, was sized to liquefy up to 42 gN2/hr at the intended storage pressure (0.2 MPa). The experiment was conducted inside an atmospheric, air-filled, refrigerated chamber simulating the average Martian daytime temperature (240 K). In this demonstration a liquefaction rate of 9.1 gN2/hr was realized, which is equivalent to 13 gO2/hr.

  6. Cooling with Superfluid Helium

    CERN Document Server

    Lebrun, P

    2014-01-01

    The technical properties of helium II (‘superfluid’ helium) are presented in view of its applications to the cooling of superconducting devices, particularly in particle accelerators. Cooling schemes are discussed in terms of heat transfer performance and limitations. Large-capacity refrigeration techniques below 2 K are reviewed, with regard to thermodynamic cycles as well as process machinery. Examples drawn from existing or planned projects illustrate the presentation. Keywords: superfluid helium, cryogenics

  7. Solutions for Liquid Nitrogen Pre-Cooling in Helium Refrigeration Cycles

    CERN Document Server

    Wagner, U

    2000-01-01

    Pre-cooling of helium by means of liquid nitrogen is the oldest and one of the most common process features used in helium liquefiers and refrigerators. Its two principle tasks are to allow or increase the rate of pure liquefaction, and to permit the initial cool-down of large masses to about 80 K. Several arrangements for the pre-cooling process are possible depending on the desired application. Each arrangement has its proper advantages and drawbacks. The aim of this paper is to review the possible process solutions for liquid nitrogen pre-cooling and their particularities.

  8. Risk management technique for liquefied natural gas facilities

    Science.gov (United States)

    Fedor, O. H.; Parsons, W. N.

    1975-01-01

    Checklists have been compiled for planning, design, construction, startup and debugging, and operation of liquefied natural gas facilities. Lists include references to pertinent safety regulations. Methods described are applicable to handling of other hazardous materials.

  9. Performance of the Helium Circulation System on a Commercialized MEG

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  11. The U.S. Geological Survey National Helium Resource Assessment

    Science.gov (United States)

    Brennan, S. T.; East, J. A., II

    2015-12-01

    In 2013, the U.S. Congress passed legislation directing the U.S. Geological Survey (USGS) to complete a national assessment of subsurface helium gas resources. As part of this assessment, the USGS has constructed a database of helium concentration from compositional analyses of produced gas. Though most data of this data is non-proprietary, helium data have been taken from both public and proprietary sources, with a majority taken from the USGS geochemical database (http://energy.usgs.gov/GeochemistryGeophysics/GeochemistryLaboratories/GeochemistryLaboratories-GeochemistryDatabase.aspx#4413382-introduction) and from the U.S. Bureau of Land Management (BLM) natural gas database. Altogether, there are over 16,000 analyses of natural gas composition compiled. In order to complete the assessment, it was necessary to correlate the well data with geologic reservoir data so that the helium concentrations could be compared with the reservoir and field-level gas production, in place gas volumes, and gas recovery factors. The well data from the compiled database were initially cross-referenced with the proprietary IHS Inc. well database, where possible. The results of that effort were then cross-referenced with three additional databases: the proprietary NRG Associates database of significant oil and gas fields of the United States, the non-proprietary U.S. Department of Energy's gas information system (GASIS), and an internal BLM reservoir and field database. These field and reservoir databases provide the data needed to estimate the in-place helium resources for fields with economic concentrations of helium. In order for helium production to be economic, the gas produced from geologic reservoirs must be greater than 0.3 mole percent (mol%), or in the case of liquefied natural gas processing, greater than 0.04 mol%. The field and reservoir specific estimates of total gas in place volumes, gas recovery factors, and helium concentrations, can be used as inputs for a

  12. Helium the disappearing element

    CERN Document Server

    Sears, Wheeler M

    2015-01-01

    The subject of the book is helium, the element, and its use in myriad applications including MRI machines, particle accelerators, space telescopes, and of course balloons and blimps. It was at the birth of our Universe, or the Big Bang, where the majority of cosmic helium was created; and stellar helium production continues. Although helium is the second most abundant element in the Universe, it is actually quite rare here on Earth and only exists because of radioactive elements deep within the Earth. This book includes a detailed history of the discovery of helium, of the commercial industry built around it, how the helium we actually encounter is produced within the Earth, and the state of the helium industry today. The gas that most people associate with birthday party balloons is running out. “Who cares?” you might ask. Well, without helium, MRI machines could not function, rockets could not go into space, particle accelerators such as those used by CERN could not operate, fiber optic cables would not...

  13. Liquefied after cataract and its surgical treatment

    Science.gov (United States)

    Bhattacharjee, Harsha; Bhattacharjee, Kasturi; Bhattacharjee, Pankaj; Das, Dipankar; Gogoi, Krishna; Arati, Diyali

    2014-01-01

    Aims: To describe liquefied after cataract (LAC) and its surgical management following an uneventful phacoemulsification with posterior chamber in-the-bag intraocular lens (IOL) implantation and continuous curvilinear capsulorrhexis (CCC). Design: Interventional case series. Materials and Methods: Eleven patients with LAC, following uneventful phacoemulsification with CCC and in-the-bag IOL implantation were enrolled. After the basic slit lamp examination, each case was investigated with Scheimpflug photography and ultrasound biomicroscopy (UBM). Each case was treated with capsular lavage. Biochemical composition of the milky fluid was evaluated and ring of anterior capsular opacity (ACO) was examined under electron microscope. Results: All 11 cases presented with blurring of vision after 6-8 years of cataract surgery with IOL implantation. All cases had IOL microvacuoles, 360° anterior capsule, and anterior IOL surface touch along with ACO, ring of Soemmering, and posterior capsule distension filled with opalescent milky fluid with whitish floppy or crystalline deposits. Biochemically, the milky fluid contained protein (800 mg/dl), albumin (100 mg/dl), sugar (105 mg/dl), and calcium (0.13%) and was bacteriologically sterile. Histologically, the dissected ACO showed fibrous tissue. All cases were successfully treated with capsular lavage with good visual recovery and with no complication. There was no recurrence of LAC during 2 years postoperative follow-up in any of the cases. Conclusions: LAC is a late complication of standard cataract surgery. It may be a spectrum of capsular bag distension syndrome (CBDS) without shallow anterior chamber and secondary glaucoma. Capsular bag lavage is a simple and effective treatment for LAC and a safe alternative to neodymium-doped yttrium aluminum garnet (Nd-YAG) capsulotomy. PMID:24881605

  14. Intramolecular quantum chaos in doped helium nanodroplets

    Science.gov (United States)

    Polyakova, E.; Stolyarov, D.; Zhang, X.; Kresin, V. V.; Wittig, C.

    2003-07-01

    A mass spectrometric depletion spectrum (17 700-18 300 cm -1) is reported for NO 2 in superfluid (0.37 K) helium nanodroplets. Gas phase NO 2 is believed to be vibronically chaotic at these energies. Transitions are broadened and blue-shifted relative to their gas phase counterparts. The spectrum is fitted reasonably well by setting all of the widths and shifts equal to 7 cm -1. Modest dispersions (i.e., 90% lie within 2 cm -1 of the central values) are consistent with quantum chaos in NO 2. Relaxation is dominated by interactions of NO 2 with its non-superfluid helium nearest neighbors.

  15. Advances in Helium Cryogenics

    Science.gov (United States)

    Sciver, S. W. Van

    This review provides a survey of major advances that have occurred in recent years in the area of helium cryogenics. Helium-temperature cryogenics is the enabling technology for a substantial and growing number of low-temperature systems from superconducting magnets to space-based experimental facilities. In recent years there have been many advances in the technology of low-temperature helium, driven mostly by new applications. However, to keep the review from being too broad, this presentation focuses mainly on three of the most significant advances. These are: (1) the development of large-scale recuperative refrigeration systems mainly for superconducting magnet applications in accelerators and other research facilities; (2) the use of stored superfluid helium (He II) as a coolant for spacebased astrophysics experiments; and (3) the application of regenerative cryocoolers operating at liquid helium temperatures primarily for cooling superconducting devices. In each case, the reader should observe that critical technologies were developed to facilitate these applications. In addition to these three primary advances, other significant helium cryogenic technologies are briefly reviewed at the end of this chapter, along with some vision for future developments in these areas.

  16. 75 FR 13644 - TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied Natural Gas Deepwater Port License...

    Science.gov (United States)

    2010-03-22

    ... Maritime Administration TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied Natural Gas...) for the TORP Terminal LP, Bienville Offshore Energy Terminal (BOET) Liquefied Natural Gas (LNG... Natural Gas Pipeline, Williams Natural Gas Pipeline, Destin Natural Gas Pipeline, and Viosca...

  17. 75 FR 72877 - Pipeline Safety: Updates to Pipeline and Liquefied Natural Gas Reporting Requirements

    Science.gov (United States)

    2010-11-26

    ... Safety: Updates to Pipeline and Liquefied Natural Gas Reporting Requirements; Final Rule #0;#0;Federal... to Pipeline and Liquefied Natural Gas Reporting Requirements AGENCY: Pipeline and Hazardous Materials... collections from operators of natural gas pipelines, hazardous liquid pipelines, and liquefied natural......

  18. 77 FR 16471 - Pipeline Safety: Implementation of the National Registry of Pipeline and Liquefied Natural Gas...

    Science.gov (United States)

    2012-03-21

    ...: Implementation of the National Registry of Pipeline and Liquefied Natural Gas Operators AGENCY: Pipeline and... registry of pipeline and liquefied natural gas operators. This notice provides updates to the information... and liquefied natural gas (LNG) operators. New operators use the national registry to obtain...

  19. 78 FR 44934 - Sabine Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied...

    Science.gov (United States)

    2013-07-25

    ... Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas... export liquefied natural gas (LNG) produced from domestic sources in an amount up to 91,250,000 million.... 3307, Order Granting Authorization to Export Liquefied Natural Gas by Vessel Pursuant to the...

  20. 78 FR 44937 - Sabine Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied...

    Science.gov (United States)

    2013-07-25

    ... Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas... export liquefied natural gas (LNG) produced from domestic sources in an amount up to 104,250,000 million... Granting Authorization to Export Liquefied Natural Gas by Vessel Pursuant to the Long-Term Contract...

  1. Liquefied gaseous fuels safety and environmental control assessment program: a status report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-05-01

    Progress is reported in research on the safety and environmental aspects of four principal liquefied gaseous material systems: liquefied natural gas (LNG), liquefied petroleum gas (LPG), hydrogen, and ammonia. Each section of the report has been abstracted and indexed individually. (JGB)

  2. 29 CFR 779.360 - Classification of liquefied-petroleum-gas sales.

    Science.gov (United States)

    2010-07-01

    ... Establishments Liquefied-Petroleum-Gas and Fuel Oil Dealers § 779.360 Classification of liquefied-petroleum-gas... are also included); and (3) Sales for use in the production of a specific product in which the gas is an essential ingredient or principal raw material, such as sales of liquefied-petroleum-gas for...

  3. 49 CFR 173.313 - UN Portable Tank Table for Liquefied Compressed Gases.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false UN Portable Tank Table for Liquefied Compressed... SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.313 UN Portable Tank Table for Liquefied Compressed Gases. The UN Portable Tank Table for Liquefied...

  4. Commissioning and operational results of helium refrigeration system at JLab for the 12GeV upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Peter N. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ganni, Venkatarao [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Dixon, Kelly D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Norton, Robert O. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Creel, Jonathan D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-12-01

    The new 4.5 K refrigerator system at the Jefferson Lab (JLab) Central Helium Liquefier (CHL-2) for the 12 GeV upgrade was commissioned in late spring of 2013, following the commissioning of the new compressor system, and has been supporting 12 GeV LINAC commissioning since that time. Six design modes were tested during commissioning, consisting of a maximum capacity, nominal capacity, maximum liquefaction, maximum refrigeration, maximum fill and a stand-by/reduced load condition. The maximum capacity was designed to support a 238 g/s, 30 K and 1.16 bar cold compressor return flow, a 15 g/s, 4.5 K liquefaction load and a 12.6 kW, 35-55 K shield load. The other modes were selected to ensure proper component sizing and selection to allow the cold box to operate over a wide range of conditions and capacities. The cold box system is comprised of two physically independent cold boxes with interconnecting transfer-lines. The outside (upper) 300-60 K vertical cold box has no turbines and incorporates a liquid nitrogen pre-cooler and 80-K beds. The inside (lower) 60-4.5 K horizontal cold box houses seven turbines that are configured in four expansion stages including one Joule-Thompson expander and a 20-K bed. The helium compression system has five compressors to support three pressure levels in the cold box. This paper will summarize the analysis of the test data obtained over the wide range of operating conditions and capacities which were tested.

  5. The liquefied natural gas infrastructure and tanker fleet sizing problem

    DEFF Research Database (Denmark)

    Koza, David Franz; Røpke, Stefan; Molas, Anna Boleda

    2017-01-01

    We consider a strategic infrastructure and tanker fleet sizing problem in the liquefied natural gas business. The goal is to minimize long-term on-shore infrastructure and tanker investment cost combined with interrelated expected cost for operating the tanker fleet. A non-linear arc-based model...

  6. Liquefied natural gas production at Hammerfest: A transforming marine community

    NARCIS (Netherlands)

    Bets, van L.K.J.; Tatenhove, van J.P.M.; Mol, A.P.J.

    2016-01-01

    Global energy demand and scarce petroleum resources require communities to adapt to a rapidly changing Arctic environment, but as well to a transforming socio-economic environment instigated by oil and gas development. This is illustrated by liquefied natural gas production by Statoil at Hammerfest,

  7. Compact, ultra-low vibration, closed-cycle helium recycler for uninterrupted operation of MEG with SQUID magnetometers

    Science.gov (United States)

    Wang, Chao; Sun, Limin; Lichtenwalter, Ben; Zerkle, Brent; Okada, Yoshio

    2016-06-01

    A closed-cycle helium recycler was developed for continuous uninterrupted operation for magnetometer-based whole-head magnetoencephalography (MEG) systems. The recycler consists of a two stage 4 K pulse-tube cryocooler and is mounted on the roof of a magnetically shielded room (MSR). A flexible liquid helium (LHe) return line on the recycler is inserted into the fill port of the MEG system in the MSR through a slotted opening in the ceiling. The helium vapor is captured through a line that returns the gas to the top of the recycler assembly. A high-purity helium gas cylinder connected to the recycler assembly supplies the gas, which, after it is liquefied, increases the level of LHe in the MEG system during the start-up phase. No storage tank for evaporated helium gas nor a helium gas purifier is used. The recycler is capable of liquefying helium with a rate of ∼17 L/d after precooling the MEG system. It has provided a fully maintenance-free operation under computer control for 7 months without refill of helium. Although the recycler is used for single-orientation operation at this initial testing site, it is designed to operate at ±20° orientations, allowing the MEG system to be tilted for supine and reclining positions. Vibration of the recycler is dampened to an ultra-low level by using several vibration isolation methods, which enables uninterrupted operation during MEG measurements. Recyclers similar to this system may be quite useful even for MEG systems with 100% magnetometers.

  8. Cosmic Ray Helium Hardening

    CERN Document Server

    Ohira, Yutaka

    2010-01-01

    Recent observations by CREAM, ATIC-2 and PAMELA experiments suggest that (1) the spectrum of cosmic ray (CR) helium is harder than that of CR proton below the knee $10^15 eV$ and (2) all CR spectra become hard at $\\gtrsim 10^{11} eV/n$. We propose a new picture that higher energy CRs are generated in more helium-rich region to explain the hardening (1) without introducing different sources for CR helium. The helium to proton ratio at $\\sim 100$ TeV exceeds the Big Bang abundance $Y=0.25$ by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in the chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium when escaping from the supernova remnant (SNR) shock. We provide a simple analytical spectrum that also fits well the hardening (2) because of the decreasing Mach number in the hot superbubble with $\\sim 10^6$ K. Our model predicts hard and con...

  9. Helium process cycle

    Science.gov (United States)

    Ganni, Venkatarao

    2007-10-09

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  10. Isolation and identification of an agar-liquefying marine bacterium and some properties of its extracellular agarases

    Directory of Open Access Journals (Sweden)

    FATURRAHMAN

    2011-10-01

    Full Text Available Faturrahman, Meryandini A, Junior MZ, Rusmana I (2011 Isolation and identification of an agar-liquefying marine bacterium and some properties of its extracellular agarases. Biodiversitas 12: 192-197. A new agar-liquefying bacterium, designated Alg3.1, was isolated from Gracilaria samples collected from the Kuta Coast at Central Lombok in West Nusa Tenggara and was identified as Aeromonas sp. on the basis of morphology, biochemical-physiological character and 16S rDNA gene sequencing. The bacterium appeared capable of liquifying agar in nutrient agar-plate within 48 hours of incubation and the agar was completely liquefied after l5 days at 29oC. When the isolate was grown in basal salts solution medium B supplemented with peptone and yeast extract, produced extracellular agarases within a short period of time (4-16 h and the maximum agarase activity was 0.489 nkat/mL at 36h after incubation.

  11. Lateral response of pile foundations in liquefiable soils

    Directory of Open Access Journals (Sweden)

    Asskar Janalizadeh

    2015-10-01

    Full Text Available Liquefaction has been a main cause of damage to civil engineering structures in seismically active areas. The effects of damage of liquefaction on deep foundations are very destructive. Seismic behavior of pile foundations is widely discussed by many researchers for safer and more economic design purposes. This paper presents a pseudo-static method for analysis of piles in liquefiable soil under seismic loads. A free-field site response analysis using three-dimensional (3D numerical modeling was performed to determine kinematic loads from lateral ground displacements and inertial loads from vibration of the superstructure. The effects of various parameters, such as soil layering, kinematic and inertial forces, boundary condition of pile head and ground slope, on pile response were studied. By comparing the numerical results with the centrifuge test results, it can be concluded that the use of the p-y curves with various degradation factors in liquefiable sand gives reasonable results.

  12. A Case Study: Foundation Design in Liquefiable Site

    Directory of Open Access Journals (Sweden)

    Tahar Ayadat

    2017-01-01

    Full Text Available The liquefaction is a phenomenon which occurs under seismic solicitation. The passage of a seismic wave (i.e. strong shaking leads, in certain geological formations, to the loss of shearing resistance in saturated sandy materials. This is caused mainly by the increase of the pore water pressure generated by the cyclical deformations. The instantaneous deconsolidation of the soil is reflected by the destruction of the soil mass; making the constructions on such soils unstable. In this geotechnical investigation a case study of foundation design on liquefiable site is described. The geotechnical investigation, carried out at Kent (Ontario, consisted of the construction of a new electrical station on a liquefiable site

  13. Synthesis and Properties of Polyurethane Resins from Liquefied Benzylated Wood

    Institute of Scientific and Technical Information of China (English)

    Yu Ping WEI; Fa CHENG; Hou Ping LI; Jiu Gao YU

    2005-01-01

    In this paper, polyurethane resins were synthesized from liquefied benzylated wood and TDI (toluene diisocyanate)-TMP (trihydromethylene propane) prepolymer. And the relation between microphase structure and properties of PU samples were also studied. The results indicated that coatings obtained had good mechanical and thermal properties. The amount of the curing agent has great effect on the degree of phase segregation. In addition, with increased the curing agent amount, the thermal stabilities were also improved.

  14. Liquefied Bleed for Stability and Efficiency of High Speed Inlets

    Science.gov (United States)

    Saunders, J. David; Davis, David; Barsi, Stephen J.; Deans, Matthew C.; Weir, Lois J.; Sanders, Bobby W.

    2014-01-01

    A mission analysis code was developed to perform a trade study on the effectiveness of liquefying bleed for the inlet of the first stage of a TSTO vehicle. By liquefying bleed, the vehicle weight (TOGW) could be reduced by 7 to 23%. Numerous simplifying assumptions were made and lessons were learned. Increased accuracy in future analyses can be achieved by: Including a higher fidelity model to capture the effect of rescaling (variable vehicle TOGW). Refining specific thrust and impulse models ( T m a and Isp) to preserve fuel-to-air ratio. Implementing LH2 for T m a and Isp. Correlating baseline design to other mission analyses and correcting vehicle design elements. Implementing angle-of-attack effects on inlet characteristics. Refining aerodynamic performance (to improve L/D ratio at higher Mach numbers). Examining the benefit with partial cooling or densification of the bleed air stream. Incorporating higher fidelity weight estimates for the liquefied bleed system (heat exchange and liquid storage versus bleed duct weights) could be added when more fully developed. Adding trim drag or 6-degree-of-freedom trajectory analysis for higher fidelity. Investigating vehicle optimization for each of the bleed configurations.

  15. Challenges of LNG (Liquefied Natural Gas Carriers in 21" Century

    Directory of Open Access Journals (Sweden)

    Marina Zanne

    2009-01-01

    Full Text Available Natural gas is relatively cheap, environmentally friendlyand energetically efficient fossil fuel that is gaining in attractivenessdaily as it can be used in many sectors. As not all consumerscan be reached by pipelines the technique of transp01tingnatural gas in the liquefied form has been developed at the beginningof 20th century but it was only in 1959 that the firstoverseas transport of liquefied natural gas ( LN G occurred. Inthe fifty years of operation LNG shipping has shown immaculatesafety records. LNG tankers can be described only in superlatives;they are without any doubt the most sophisticated and·expensive ships that sail around the globe, they demand specialattention when navigating to or out of harbours and need to bemanned with the most educated and experienced crew. LNGmarket is expanding and changing; demand is surpassing theproductivity, new importing and exporting countries appear,LNG fleet is growing in capacity and number at high pace, exploitationcontracts for the ships are being modified giving theopportunity for new companies to enter( . .. . The paper givesan overview on liquefied natural gas market and the historic developmentof LNG shipping. It focuses on the recent boom inLNG shipping and emphasises questions concerning the safety,crewing and exploitation of the LNG tankers in the future.

  16. Preparation of liquefied wood-based resins and their application in molding material

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiu-hui; Zhao Guang-jie; Yu Li-li; Jie Shu-jun

    2007-01-01

    To investigate value in use of liquefied wood-based resin applications in molding material, Chinese fir (Cunninghamia lanceolata) and poplar (Populus tomentosa) wood meal were liquefied in phenol. The reactant was co-condensed with formaldehyde to obtain liquefied wood-based resin. For this paper, we investigated the characterization of the resin and its application in molding material. The result shows that the basic properties of liquefied wood-based resin were satisfactory; the bonding strength of plywood prepared with liquefied Chinese fir and liquefied poplar resin can reach 1.54 and 1.00 MPa, respectively. The compression strengths of the molding material prepared with two kinds of liquefied wood resin were 73.01 and 73.58 MPa, almost the same as that of PF resin molding material. The limiting volume swelling of molding material made with liquefied Chinese resin and liquefied poplar resin were 8.5% and 8.3%, thickness swelling rates of water absorption were 3.3% and 4.2%, and the maximum weight ratios of water absorption were 25.9% and 26.2%, respectively. The soil burial test result shows that the weight loss rate of the molding materials made with liquefied Chinese resin and liquefied poplar resin were 8.3% and 9.1% and that of the PF resin molding material was 7.9%. After the soil internment test, the reduction ratio of compression strength of the two kinds of molding material achieved 16.9%and 17.7%, while that of the PF resin molding material was 15.4%. The test results of wood fungi inoculation on the three surfaces of the molding material indicate the breeding rate of molding material prepared with liquefied Chinese resin and liquefied poplar resin were at level 4 and that of PF resin molding material was at level 1 of the ISO standard.

  17. Helium anion formation inside helium droplets

    Science.gov (United States)

    Maalouf, Elias Jabbour Al; Reitshammer, Julia; Ribar, Anita; Scheier, Paul; Denifl, Stephan

    2016-07-01

    The formation of He∗- is examined with improved electron energy resolution of about 100 meV utilizing a hemispherical electron monochromator. The work presented provides a precise determination of the three previously determined resonance peak positions that significantly contribute to the formation of He∗- inside helium nanodroplets in the energy range from 20 eV to 29.5 eV. In addition, a new feature is identified located at 27.69 ± 0.18 eV that we assign to the presence of O2 as a dopant inside the droplet. With increasing droplet size a small blue shift of the resonance positions is observed. Also for the relatively low electron currents used in the present study (i.e., 15-70 nA) a quadratic dependence of the He∗- ion yield on the electron current is observed. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  18. Temperature distribution and control in liquefied petroleum gas fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Li Wang; Ping Wu; Yanping Zhang; Jing Yang; Lige Tong

    2004-01-01

    Temperature distribution and control have been investigated in a liquefied petroleum gas (LPG) fluidized bed with hollow corundum spheres (A12O3) of 0.867-1.212 mm in diameter at moderately high temperatures (800-1100℃). Experiments were carried out for the air consumption coefficient α in the range of 0.3 to 1.0 and the fluidization number N in the range of 1.3 to 3.0. Particle properties, initial bed height, α and N all affect temperature distribution in the bed. Bed temperature can be adjusted about 200℃ by combined the adjusting of α and N.

  19. High Efficiency Regenerative Helium Compressor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Helium plays several critical rolls in spacecraft propulsion. High pressure helium is commonly used to pressurize propellant fuel tanks. Helium cryocoolers can be...

  20. Cavitation in liquid helium

    Energy Technology Data Exchange (ETDEWEB)

    Finch, R. D.; Kagiwada, R.; Barmatz, M.; Rudnick, I.

    1963-11-15

    Ultrasonic cavitation was induced in liquid helium over the temperature range 1.2 to 2.3 deg K, using a pair of identical transducers. The transducers were calibrated using a reciprocity technique and the cavitation threshold was determined at 90 kc/s. It was found that this threshold has a sharp peak at the lambda point, but is, at all temperatures quite low, with an approximate range of 0.001 to 0.01 atm. The significance of the results is discussed. (auth)

  1. Regimes Of Helium Burning

    CERN Document Server

    Timmes, F X

    2000-01-01

    The burning regimes encountered by laminar deflagrations and ZND detonations propagating through helium-rich compositions in the presence of buoyancy-driven turbulence are analyzed. Particular attention is given to models of X-ray bursts which start with a thermonuclear runaway on the surface of a neutron star, and the thin shell helium instability of intermediate-mass stars. In the X-ray burst case, turbulent deflagrations propagating in the lateral or radial directions encounter a transition from the distributed regime to the flamlet regime at a density of 10^8 g cm^{-3}. In the radial direction, the purely laminar deflagration width is larger than the pressure scale height for densities smaller than 10^6 g cm^{-3}. Self-sustained laminar deflagrations travelling in the radial direction cannot exist below this density. Similarily, the planar ZND detonation width becomes larger than the pressure scale height at 10^7 g cm^{-3}, suggesting that a steady-state, self-sustained detonations cannot come into exista...

  2. Helium diffusion in carbonates

    Science.gov (United States)

    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

  3. A Comparative Study of Liquefied Natural Gas: An Overview

    Directory of Open Access Journals (Sweden)

    Muhammad Khan Memon

    2014-05-01

    Full Text Available Natural gas is the world’s fastest growing fuel and being produced by many countries of the world in the commercial quantities. Increasing natural gas price and new development in the technologies, liquefied natural gas industry is economically attractive in the major gas exporting countries. Liquefied Natural Gas (LNG is an important energy source and continued to contribute the growth of natural gas industry. The new advance LNG technology is used for natural gas transportation for long distances. LNG can be transported by the large insulated cryogenic tankers at affordable cost. This study presents an overview of LNG liquidation facilities from natural gas as feed gas to LNG storage and transport. The main objective of the study is to highlight the current data for reviewers on LNG world market, mainly on LNG production, supply, demand, price and new development of LNG plants. The technology is growing gradually with increasing number of LNG consuming countries in overall the world. In the near future, LNG price may be affected by the advanced shale gas production in the United States of America and China. Australia becomes the world second largest exporter of LNG market after Qatar. Australia will increase LNG supply by 15 Bcf/day from 2014 and accounting for 25% of world LNG production by 2030. Global LNG production forecast will be reached 540 Bcm by 2020 and LNG trade will be reached 425 Mtpa by 2025. New countries are interested to enter in the LNG world market as importers and exporters.

  4. Helium in near Earth orbit

    CERN Document Server

    Alcaraz, J; Ambrosi, G; Anderhub, H; Ao, L; Arefev, A; Azzarello, P; Babucci, E; Baldini, L; Basile, M; Barancourt, D; Barão, F; Barbier, G; Barreira, G; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Béné, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Bizzaglia, S; Blasko, S; Bölla, G; Boschini, M; Bourquin, Maurice; Brocco, L; Bruni, G; Buénerd, M; Burger, J D; Burger, W J; Cai, X D; Camps, C; Cannarsa, P; Capell, M; Casadei, D; Casaus, J; Castellini, G; Cecchi, C; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Tzi Hong Chiueh; Chuang, Y L; Cindolo, F; Commichau, V; Contin, A; Cristinziani, M; Da Cunha, J P; Dai, T S; Deus, J D; Dinu, N; Djambazov, L; D'Antone, I; Dong, Z R; Emonet, P; Engelberg, J; Eppling, F J; Eronen, T; Esposito, G; Extermann, Pierre; Favier, Jean; Fiandrini, E; Fisher, P H; Flügge, G; Fouque, N; Galaktionov, Yu; Gervasi, M; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Huang, M A; Hungerford, W; Ionica, M; Ionica, R; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kenny, J; Kim, W; Klimentov, A; Kossakowski, R; Koutsenko, V F; Kräber, M H; Laborie, G; Laitinen, T; Lamanna, G; Laurenti, G; Lebedev, A; Lee, S C; Levi, G; Levchenko, P M; Liu, C L; Liu Hong Tao; Lopes, I; Lu, G; Lü, Y S; Lübelsmeyer, K; Luckey, D; Lustermann, W; Maña, C; Margotti, A; Mayet, F; McNeil, R R; Meillon, B; Menichelli, M; Mihul, A; Mourão, A M; Mujunen, A; Palmonari, F; Papi, A; Park, I H; Pauluzzi, M; Pauss, Felicitas; Perrin, E; Pesci, A; Pevsner, A; Pimenta, M; Plyaskin, V; Pozhidaev, V; Pohl, M; Postolache, V; Produit, N; Rancoita, P G; Rapin, D; Raupach, F; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Röser, U; Roissin, C; Sagdeev, R; Sartorelli, G; Schultz von Dratzig, A; Schwering, G; Scolieri, G; Seo, E S; Shoutko, V; Shoumilov, E; Siedling, R; Son, D; Song, T; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tornikoski, M; Torsti, J; Trümper, J E; Ulbricht, J; Urpo, S; Usoskin, I; Valtonen, E; Van den Hirtz, J; Velcea, F; Velikhov, E P; Verlaat, B; Vetlitskii, I; Vezzu, F; Vialle, J P; Viertel, Gert M; Vitè, Davide F; Von Gunten, H P; Waldmeier-Wicki, S; Wallraff, W; Wang, B C; Wang, J Z; Wang, Y H; Wiik, K; Williams, C; Wu, S X; Xia, P C; Yan, J L; Yan Lu Guang; Yang, C G; Yang, M; Ye Shu Wei; Yeh, P; Xu, Z Z; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B; Zuccon, P

    2000-01-01

    The helium spectrum from 0.1 to 100 GeV/nucleon was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at altitudes near 380 km. Above the geomagnetic cutoff the spectrum is parameterized by a power law. Below the geomagnetic cutoff a second helium spectrum was observed. In the second helium spectra over the energy range 0.1 to 1.2 GeV/nucleon the flux was measured to be (6.3+or-0.9)*10/sup -3/ (m/sup 2/ sec sr)/sup -1/ and more than ninety percent of the helium was determined to be /sup 3/He (at the 90% CL). Tracing helium from the second spectrum shows that about half of the /sup 3/He travel for an extended period of time in the geomagnetic field and that they originate from restricted geographic regions similar to protons and positrons. (22 refs).

  5. 46 CFR 111.105-32 - Bulk liquefied flammable gas and ammonia carriers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Bulk liquefied flammable gas and ammonia carriers. 111... gas and ammonia carriers. (a) Each vessel that carries bulk liquefied flammable gases or ammonia as a.... (2) The term “gas-dangerous” does not include the weather deck of an ammonia carrier. (c)...

  6. 30 CFR 75.1106-2 - Transportation of liquefied and nonliquefied compressed gas cylinders; requirements.

    Science.gov (United States)

    2010-07-01

    ... Fire Protection § 75.1106-2 Transportation of liquefied and nonliquefied compressed gas cylinders... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Transportation of liquefied and nonliquefied compressed gas cylinders; requirements. 75.1106-2 Section 75.1106-2 Mineral Resources MINE SAFETY AND...

  7. 75 FR 60095 - Sempra LNG Marketing, LLC; Application for Blanket Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2010-09-29

    ... LNG Marketing, LLC; Application for Blanket Authorization To Export Liquefied Natural Gas AGENCY..., by Sempra LNG Marketing, LLC (Sempra), requesting blanket authorization to export up to a total of 250 billion cubic feet (Bcf) of foreign sourced liquefied natural gas (LNG) for a two-year...

  8. 18 CFR 157.212 - Synthetic and liquefied natural gas facilities.

    Science.gov (United States)

    2010-04-01

    ... of the Natural Gas Act for Certain Transactions and Abandonment § 157.212 Synthetic and liquefied... liquefied natural gas and that are not “related jurisdictional natural gas facilities” as defined in § 153.2... natural gas facilities. 157.212 Section 157.212 Conservation of Power and Water Resources FEDERAL...

  9. 75 FR 38092 - The Dow Chemical Company; Application for Blanket Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2010-07-01

    ... Chemical Company; Application for Blanket Authorization To Export Liquefied Natural Gas AGENCY: Office of... The Dow Chemical Company (Dow), requesting blanket authorization to export liquefied natural gas (LNG... equivalent of 390 billion cubic feet (Bcf) of natural gas on a short-term or spot market basis. The LNG...

  10. 75 FR 19954 - Cheniere Marketing, LLC; Application for Blanket Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2010-04-16

    ... Cheniere Marketing, LLC; Application for Blanket Authorization To Export Liquefied Natural Gas AGENCY... Cheniere Marketing, LLC (CMI), requesting blanket authorization to export liquefied natural gas (LNG) that... 500 Billion cubic feet (Bcf) of natural gas on a short-term or spot market basis. The LNG would...

  11. 78 FR 26056 - Waterway Suitability Assessment for Expansion of Liquefied Gas Terminals; Nederland, TX

    Science.gov (United States)

    2013-05-03

    ... SECURITY Coast Guard Waterway Suitability Assessment for Expansion of Liquefied Gas Terminals; Nederland... proposed expansion of its Liquefied Hazardous Gas (LHG) facility in Nederland, Texas, and increased LHG... solicit public comments on the proposed increase in LHG marine traffic in Nederland, Texas....

  12. 42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Compressed breathing gas and liquefied breathing... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed breathing gas and liquefied breathing gas containers; minimum requirements. (a) Compressed breathing gas...

  13. Effects of helium on titanium films and the helium diffusion

    Institute of Scientific and Technical Information of China (English)

    SONG YingMin; LUO ShunZhong; LONG XingGui; AN Zhu; LIU Ning; PANG HongChao; WU XingChun; YANG BenFu; ZHENG SiXiao

    2008-01-01

    Using direct current-magnetron sputtering, Helium-trapped Ti films with a He/Ar mixture was studied. The relative helium content, helium depth profiles for the Ti films and crystallization capacity were analyzed by Enhanced Proton Backscattering Spectrometry (EPBS) and X-ray diffraction (XRD). It was found that helium diffusion enhanced as more helium trapping into Ti films, and the He holding ratios were 95.9%, 94.9%, 93.9%, 82.8% when the Ti films with the He/Ti of concentrations of 9.7 at.Q, 19.5 at.Q, 19.7 at.Q, 48.3 at.% were measured again 4 months later, respectively. The diffraction peaks be-came weak and wider, the peak of (002) plane was shifted to smaller diffraction angles and the relevant interplanar spacing d(hkl) increased gradually as more helium trapping into Ti films. The main peak was made trending to the (101) plane by both higher deposition temperature and more helium trapping.

  14. Ion temperature anisotropy in high power helium neutral beam fuelling experiments in JET

    Energy Technology Data Exchange (ETDEWEB)

    Maas, A.C.; Core, W.G.F.; Gerstel, U.C.; Von Hellermann, M.G.; Koenig, R.W.T.; Marcus, F.B. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    During helium beam fuelling experiments in JET, distinctive anisotropic features have been observed in the velocity distribution function describing both fast and thermal alpha particle populations. During the initial fuelling phase the central helium ion temperature observed perpendicular to the magnetic field is higher than the central electron temperature, while the central helium ion temperature observed parallel to the magnetic field is lower than or equal to the central electron temperature. In order to verify temperature measurements of both perpendicular and parallel lines of sight, other independent methods of deducing the ion temperature are investigated: deuterium ion temperature, deuterium density, comparison with neutron rates and profiles (influence of a possible metastable population of helium). 6 refs., 7 figs.

  15. 77 FR 72837 - Golden Pass Products LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas...

    Science.gov (United States)

    2012-12-06

    ... Pass Products LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced... to export domestically produced liquefied natural gas (LNG) in an amount up to the equivalent of 740... Liquefied Natural Gas by Vessel from the Golden Pass LNG Terminal to Free Trade Agreement Nations,...

  16. 78 FR 21351 - Orders Granting Authority to Import and Export Natural Gas, To Import Liquefied Natural Gas, To...

    Science.gov (United States)

    2013-04-10

    ... Granting Authority to Import and Export Natural Gas, To Import Liquefied Natural Gas, To Export Liquefied Natural Gas, and Vacating Prior Authority During February 2013 FE Docket Nos. J.P. MORGAN COMMODITIES... and liquefied natural gas and vacating prior authority. These orders are summarized in the...

  17. 77 FR 64964 - Cheniere Marketing, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas...

    Science.gov (United States)

    2012-10-24

    ... Cheniere Marketing, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced... Liquefied Natural Gas by Vessel from the Proposed Corpus Christi Liquefaction Project to Free Trade... Project site, natural gas will be liquefied into LNG and stored in three 160,000 cubic meters...

  18. 77 FR 72840 - CE FLNG, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced...

    Science.gov (United States)

    2012-12-06

    ..., LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced From Domestic... million tons per annum (mtpa) of domestically produced liquefied natural gas (LNG), the equivalent of... facilities to receive and liquefy domestic natural gas at the proposed Project. CE FLNG states that...

  19. 33 CFR 165.110 - Safety and Security Zone; Liquefied Natural Gas Carrier Transits and Anchorage Operations, Boston...

    Science.gov (United States)

    2010-07-01

    ...; Liquefied Natural Gas Carrier Transits and Anchorage Operations, Boston, Massachusetts. 165.110 Section 165... Limited Access Areas First Coast Guard District § 165.110 Safety and Security Zone; Liquefied Natural Gas... ahead and one mile astern, and 500 yards on each side of any liquefied natural gas carrier (LNGC)...

  20. Alkali-helium snowball complexes formed on helium nanodroplets.

    Science.gov (United States)

    Müller, S; Mudrich, M; Stienkemeier, F

    2009-07-28

    We systematically investigate the formation and stability of snowballs formed by femtosecond photoionization of small alkali clusters bound to helium nanodroplets. For all studied alkali species Ak = (Na,K,Rb,Cs) we observe the formation of snowballs Ak(+)He(N) when multiply doping the droplets. Fragmentation of clusters Ak(N) upon ionization appears to enhance snowball formation. In the case of Na and Cs we also detect snowballs Ak(2) (+)He(N) formed around Ak dimer ions. While the snowball progression for Na and K is limited to less than 11 helium atoms, the heavier atoms Rb and Cs feature wide distributions at least up to Ak(+)He(41). Characteristic steps in the mass spectra of Cs-doped helium droplets are found at positions consistent with predictions on the closure of the first shell of helium atoms around the Ak(+) ion based on variational Monte Carlo simulations.

  1. Transferring superfluid helium in space

    Science.gov (United States)

    Kittel, Peter

    1986-01-01

    A simple thermodynamic model of a transfer system for resupplying liquid helium in space is presented, with application to NASA projects including the Space Infrared Telescope Facility, the Large Deployable Reflector, and the Hubble Space Telescope. The relations between different thermodynamic regimes that can be expected in the transfer line are used to study the relative efficiencies of various possible transfer techniques. Low heat leak into the transfer line, particularly at point sources such as the coupling, is necesssary for efficient transfer of liquid helium, and proper selection of supply tank temperature is important during helium resupply.

  2. Electronic properties of physisorbed helium

    Energy Technology Data Exchange (ETDEWEB)

    Kossler, Sarah

    2011-09-22

    This thesis deals with electronic excitations of helium physisorbed on metal substrates. It is studied to what extent the electronic properties change compared to the gas phase due to the increased helium density and the proximity of the metal. Furthermore, the influence of different substrate materials is investigated systematically. To this end, up to two helium layers were adsorbed onto Ru (001), Pt (111), Cu (111), and Ag (111) surfaces in a custom-made cryostat. These samples were studied spectroscopically using synchrotron radiation and a time-of-flight detector. The experimental results were then analyzed in comparison with extensive theoretical model calculations.

  3. Trapping fermionic and bosonic helium atoms

    NARCIS (Netherlands)

    Stas, R.J.W.

    2005-01-01

    This thesis presents experimental and theoretical work performed at the Laser Centre of the Vrije Universiteit in Amsterdam to study laser-cooled metastable triplet helium atoms. Samples containing about 3x10^8 helium atoms-either fermionic helium-3 atoms, bosonic helium-4 atoms or mixtures thereof

  4. Transient Analysis of Monopile Foundations Partially Embedded in Liquefied Soil

    DEFF Research Database (Denmark)

    Barari, Amin; Bayat, Mehdi; Meysam, Saadati

    2015-01-01

    In this study, the authors present a coupled fluid-structures-seabed interaction analysis of a monopile type of wind turbine foundations in liquefiable soils. A two dimensional analysis is performed with a nonlinear stiffness degradation model incorporated in the finite difference program Fast...... Lagrangian Analysis of Continua (FLAC), which captured the fundamental mechanisms of the monopiles in saturated granular soil. The effects of inertia and the kinematic flow of soil are investigated separately, to highlight the importance of considering the combined effect of these phenomena on the seismic...... design of offshore monopiles. Different seismic loads, such as those experienced in the Kobe, Santa Cruz, Loma Prieta, Kocaeli, and Morgan Hill earthquakes, are analyzed. The pore water pressure development, relative displacements, soil skeleton deformation and monopile bending moment are obtained...

  5. Cover stones on liquefiable soil bed under waves

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Hatipoglu, Figen; Fredsøe, Jørgen

    2010-01-01

    of stone layers (including the effect of an intermediate filter layer) were investigated. Pore pressure was measured across the soil depth. The experiments show that the soil liquefaction depended mainly on two parameters: the packing density of stones, and the number of stone layers. When the liquefaction...... occurs, stones sink in the soil. Mechanisms of liquefaction and sinking are described, and practical guidelines are recommended.......The paper describes the results of an experimental study on the behavior of cover stones on a liquefiable soil bed exposed to a progressive wave. The soil was silt with d50=0.098mm. Stones, the size of 4cm, were used as cover material. The effect of packing density of stones, and that of number...

  6. Development of liquid helium-3 target for experimental studies of antikaon-nucleon interaction at J-PARC

    CERN Document Server

    Iio, M; Sato, M; Enomoto, S; Hashimoto, T; Suzuki, S; Iwasaki, M; Hayano, R S

    2012-01-01

    A liquid helium-3 target system was developed for experimental studies of kaonic atoms and kaonic nuclei at J-PARC. helium-3 gas is liquefied in a heat exchanger cooled below 3.2 K by decompression of liquid helium-4. To maintain a large acceptance of the cylindrical detector system for decay particles of kaonic nuclei, efficient heat transport between the separate target cell and the main unit is realized using circulation of liquid helium-3. To minimize the amount of material, a vacuum vessel containing a carbon fiber reinforced plastic cylinder having an inside diameter of 150 mm and a thickness of 1 mm was produced. A target cell made of pure beryllium and beryllium-aluminum alloy was developed not only to minimize the amount of material but to obtain also high x-ray transmission. During a cooling test, the target cell was kept at 1.3 K at a pressure of 33 mbar. The total estimated heat load to the components including the target cell and heat exchanger cooled by liquid helium-4 decompression, was 0.21 W,...

  7. Spectra of Cold Molecular Ions from Hot Helium Nanodroplets

    Science.gov (United States)

    Drabbels, Marcel

    2012-06-01

    The function of a molecule is intimately related to its structure. Accordingly, in the quest for a better understanding of molecular function, the development of spectroscopic methods to elucidate molecular structures increasingly takes central stage. The amount of detail that can be derived from spectra depends on the experimental conditions, most notably on the temperature of the sample and the intermolecular interactions a molecule experiences. Helium nanodroplets provide in this respect an almost ideal matrix [1, 2]. For neutral molecules, helium nanodroplet spectroscopy thus has led to important discoveries related to the structure of key molecular systems and has provided insight into the mechanisms underlying chemical reactions. Compared to the level of sophistication that has been reached for neutrals, the spectroscopic exploration of ions is still in its infancy. The use of helium droplets as a cryogenic matrix could potentially solve many of the technical challenges associated with recording high-resolution spectra of cold molecular ions. Here, we will present a method to record spectra of ion containing helium nanodroplets that finds its roots in the nonthermal cooling dynamics of excited molecular ions. In addition, spectra of several molecular ions will be present and the influence of the helium environment on these spectra will be discussed. [1] G. Scoles, and K. K. Lehmann, Science 287, 2429 (2000). [2] J. P. Toennies, and A. F. Vilesov, Angew. Chem. Int. Ed. 43, 2622 (2004).

  8. ITER helium ash accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, J.T.; Hillis, D.L.; Galambos, J.; Uckan, N.A. (Oak Ridge National Lab., TN (USA)); Dippel, K.H.; Finken, K.H. (Forschungszentrum Juelich GmbH (Germany, F.R.). Inst. fuer Plasmaphysik); Hulse, R.A.; Budny, R.V. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

    1990-01-01

    Many studies have shown the importance of the ratio {upsilon}{sub He}/{upsilon}{sub E} in determining the level of He ash accumulation in future reactor systems. Results of the first tokamak He removal experiments have been analysed, and a first estimate of the ratio {upsilon}{sub He}/{upsilon}{sub E} to be expected for future reactor systems has been made. The experiments were carried out for neutral beam heated plasmas in the TEXTOR tokamak, at KFA/Julich. Helium was injected both as a short puff and continuously, and subsequently extracted with the Advanced Limiter Test-II pump limiter. The rate at which the He density decays has been determined with absolutely calibrated charge exchange spectroscopy, and compared with theoretical models, using the Multiple Impurity Species Transport (MIST) code. An analysis of energy confinement has been made with PPPL TRANSP code, to distinguish beam from thermal confinement, especially for low density cases. The ALT-II pump limiter system is found to exhaust the He with maximum exhaust efficiency (8 pumps) of {approximately}8%. We find 1<{upsilon}{sub He}/{upsilon}{sub E}<3.3 for the database of cases analysed to date. Analysis with the ITER TETRA systems code shows that these values would be adequate to achieve the required He concentration with the present ITER divertor He extraction system.

  9. Recovery of Bio-Oil from Industrial Food Waste by Liquefied Dimethyl Ether for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Kiyoshi Sakuragi

    2016-02-01

    Full Text Available The development of new energy sources has become particularly important from the perspective of energy security and environmental protection. Therefore, the utilization of waste resources such as industrial food wastes (IFWs in energy production is expected. The central research institute of electric power industry (CRIEPI, Tokyo, Japan has recently developed an energy-saving oil-extraction technique involving the use of liquefied dimethyl ether (DME, which is an environmentally friendly solvent. In this study, three common IFWs (spent coffee grounds, soybean, and rapeseed cakes were evaluated with respect to oil yield for biodiesel fuel (BDF production by the DME extraction method. The coffee grounds were found to contain 16.8% bio-oil, whereas the soybean and rapeseed cakes contained only approximately 0.97% and 2.6% bio-oil, respectively. The recovered oils were qualitatively analysed by gas chromatography-mass spectrometry. The properties of fatty acid methyl esters derived from coffee oil, such as kinematic viscosity, pour point, and higher heating value (HHV, were also determined. Coffee grounds had the highest oil content and could be used as biofuel. In addition, the robust oil extraction capability of DME indicates that it may be a favourable alternative to conventional oil extraction solvents.

  10. Stability of submerged rock berms exposed to motion of liquefied soil in waves

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Dixen, Figen Hatipoglu; Fredsøe, Jørgen

    2011-01-01

    The paper describes the results of an experimental study on the behaviour of a submerged rock berm in liquefied backfill soil. The soil is liquefied by waves, and the rock berm is subject to the orbital motion of the liquefied soil. The soil used in the experiments was silt with d50=0.075mm....... Various berm materials were used, stones of size 0.74–2.5cm, plastic balls of size 3.6cm, brass of size 2.5cm and steel of size 1.0cm. The experiments show that rock berms that are stable under very large waves can be unstable when they are exposed to the motion of liquefied soil. The limited data...

  11. 77 FR 38128 - Withdrawal of TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied Natural Gas (LNG...

    Science.gov (United States)

    2012-06-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Maritime Administration Withdrawal of TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied Natural Gas (LNG) Deepwater Port Application AGENCY: Maritime Administration, DOT. ACTION: Deepwater...

  12. VAPOR MIXER FOR GELATINIZATION OF STARCH IN LIQUEFYING STATION

    Directory of Open Access Journals (Sweden)

    V. V. Ananskikh

    2015-01-01

    Full Text Available Starch hydrolysis is main technological process in production of starch sweeteners. Acid hydrolysis of starch using hydrochloric acid is carried out very fast but it does not allow to carry out full hydrolysis and to produce products with given carbohydrate composition. Bioconversion of starch allows to eliminate these limitations. At production of starch sweeteners from starch using enzymes starch hydrolysis is carried out in two stages At first starch – starch liquefaction the rapid increase of viscosity takes place which requires intensive mixing. Liquefying station consists of jet-cooker, holder, pressure regulator and evaporator. Jet-cooker of starch is its main part, starch is quickly turns into soluble (gelatinized state and it is partially liquefied by injection of starch suspension by flow of water vapor under pressure not less than 0,8 MPa. Heat and hydraulic calculation were carried out in order to determine constructive sizes of mixer for cooking of starch. The main hydraulic definable parameters are pressure drop in mixer, vapor pressure at mixer inlet, daily capacity of station by glucose syrup M, product consumption (starch suspension, diameter of inlet section of vapor nozzle. The goal of calculation was to determine vapor consumption M1, diameter d2 of outlet section of confuser injector, length l2 of gelatinization section. For heat calculation there was used Shukhov’s formula along with heat balance equation for gelatinization process. The numerical solution obtained with adopted assumptions given in applied mathematical package MATHCAD, for M = 50 t/day gives required daily vapor consumption M1 = 14,446 т. At hydraulic calculation of pressure drop in mixer there was used Bernoulli’s theorem. Solving obtained equations using MATHCAD found diameter of outlet section of consufer d2 = 0,023 м, vapor pressure inside of mixer p2 = 3,966·105 Па, l2 = 0,128 м. Developed method of calculation is used to determine

  13. Two Heat-Transfer Improvements for Gas Liquefiers

    Science.gov (United States)

    Martin, Jerry L.

    2005-01-01

    Two improvements in heat-transfer design have been investigated with a view toward increasing the efficiency of refrigerators used to liquefy gases. The improvements could contribute to the development of relatively inexpensive, portable oxygen liquefiers for medical use. A description of the heat-transfer problem in a pulse-tube refrigerator is prerequisite to a meaningful description of the first improvement. In a pulse-tube refrigerator in particular, one of in-line configuration heat must be rejected from two locations: an aftercooler (where most of the heat is rejected) and a warm heat exchanger (where a small fraction of the total input power must be rejected as heat). Rejection of heat from the warm heat exchanger can be problematic because this heat exchanger is usually inside a vacuum vessel. When an acoustic-inertance tube is used to provide a phase shift needed in the pulse-tube cooling cycle, another problem arises: Inasmuch as the acoustic power in the acoustic-inertance tube is dissipated over the entire length of the tube, the gas in the tube must be warmer than the warm heat exchanger in order to reject heat at the warm heat exchanger. This is disadvantageous because the increase in viscosity with temperature causes an undesired increase in dissipation of acoustic energy and an undesired decrease in the achievable phase shift. Consequently, the overall performance of the pulse-tube refrigerator decreases with increasing temperature in the acoustic-inertance tube. In the first improvement, the acoustic-inertance tube is made to serve as the warm heat exchanger and to operate in an approximately isothermal condition at a lower temperature, thereby increasing the achievable phase shift and the overall performance of the refrigerator. This is accomplished by placing the acoustic-inertance tube inside another tube and pumping a cooling fluid (e.g., water) in the annular space between the tubes. Another benefit of this improvement is added flexibility of

  14. Flow field analysis of high-speed helium turboexpander for cryogenic refrigeration and liquefaction cycles

    Science.gov (United States)

    Sam, Ashish Alex; Ghosh, Parthasarathi

    2017-03-01

    Turboexpander constitutes one of the vital components of Claude cycle based helium refrigerators and liquefiers that are gaining increasing technological importance. These turboexpanders which are of radial inflow in configuration are generally high-speed micro turbines, due to the low molecular weight and density of helium. Any improvement in efficiency of these machines requires a detailed understanding of the flow field. Computational Fluid Dynamics analysis (CFD) has emerged as a necessary tool for the determination of the flow fields in cryogenic turboexpanders, which is often not possible through experiments. In the present work three-dimensional transient flow analysis of a cryogenic turboexpander for helium refrigeration and liquefaction cycles were performed using Ansys CFX®, to understand the flow field of a high-speed helium turboexpander, which in turn will help in taking appropriate decisions regarding modifications of established design methodology for improved efficiency of these machines. The turboexpander is designed based on Balje's nsds diagram and the inverse design blade profile generation formalism prescribed by Hasselgruber and Balje. The analyses include the study of several losses, their origins, the increase in entropy due to these losses, quantification of losses and the effects of various geometrical parameters on these losses. Through the flow field analysis it was observed that in the nozzle, flow separation at the nozzle blade suction side and trailing edge vortices resulted in loss generation, which calls for better nozzle blade profile. The turbine wheel flow field analysis revealed that the significant geometrical parameters of the turbine wheel blade like blade inlet angle, blade profile, tip clearance height and trailing edge thickness need to be optimised for improved performance of the turboexpander. The detailed flow field analysis in this paper can be used to improve the mean line design methodology for turboexpanders used

  15. Liquefied Gaseous Fuels Safety and Environmental Control Assessment Program: second status report

    Energy Technology Data Exchange (ETDEWEB)

    1980-10-01

    The Assistant Secretary for Environment has responsibility for identifying, characterizing, and ameliorating the environmental, health, and safety issues and public concerns associated with commercial operation of specific energy systems. The need for developing a safety and environmental control assessment for liquefied gaseous fuels was identified by the Environmental and Safety Engineering Division as a result of discussions with various governmental, industry, and academic persons having expertise with respect to the particular materials involved: liquefied natural gas, liquefied petroleum gas, hydrogen, and anhydrous ammonia. This document is arranged in three volumes and reports on progress in the Liquefied Gaseous Fuels (LGF) Safety and Environmental Control Assessment Program made in Fiscal Year (FY)-1979 and early FY-1980. Volume 1 (Executive Summary) describes the background, purpose and organization of the LGF Program and contains summaries of the 25 reports presented in Volumes 2 and 3. Annotated bibliographies on Liquefied Natural Gas (LNG) Safety and Environmental Control Research and on Fire Safety and Hazards of Liquefied Petroleum Gas (LPG) are included in Volume 1.

  16. Modeling and Diagnostic Software for Liquefying-Fuel Rockets

    Science.gov (United States)

    Poll, Scott; Iverson, David; Ou, Jeremy; Sanderfer, Dwight; Patterson-Hine, Ann

    2005-01-01

    A report presents a study of five modeling and diagnostic computer programs considered for use in an integrated vehicle health management (IVHM) system during testing of liquefying-fuel hybrid rocket engines in the Hybrid Combustion Facility (HCF) at NASA Ames Research Center. Three of the programs -- TEAMS, L2, and RODON -- are model-based reasoning (or diagnostic) programs. The other two programs -- ICS and IMS -- do not attempt to isolate the causes of failures but can be used for detecting faults. In the study, qualitative models (in TEAMS and L2) and quantitative models (in RODON) having varying scope and completeness were created. Each of the models captured the structure and behavior of the HCF as a physical system. It was noted that in the cases of the qualitative models, the temporal aspects of the behavior of the HCF and the abstraction of sensor data are handled outside of the models, and it is necessary to develop additional code for this purpose. A need for additional code was also noted in the case of the quantitative model, though the amount of development effort needed was found to be less than that for the qualitative models.

  17. Evaluation of burn injuries related to liquefied petroleum gas.

    Science.gov (United States)

    Tarim, Mehmet Akin

    2014-01-01

    Liquefied petroleum gas (LPG) is a fuel that is widely used for domestic, agricultural, and industrial purposes. LPG is also commonly used in restaurants, industries, and cars; however, the home continues to be the main site for accidents. In Turkey, the increased usage of LPG as a cooking or heating fuel has resulted in many burn injuries from LPG mishaps. Between January 2000 and June 2011, 56 LPG-burned patients were compared with 112 flame-burned patients. There were no significant differences with respect to the mean age, sex, hospitalization time, and mortality in both groups. In the LPG-caused burn cases, 41 burns (73.2%) occurred at home, seven (12.5) were work-related mishaps, and eight (14.3) were associated with car accidents. The majority of the LPG burns (82%, 46 patients) resulted from a gas leak, and 18% of them were related to the failure to close LPG tubes in the patients' kitchens (10 patients). Burns to the face and neck (82 vs 67%, P = .039) and upper (62 vs 23%, P = .000) and lower (70 vs 45%, P = .002) extremities were significantly higher in LPG-caused burn cases than flame-burned cases. General awareness regarding the risk of LPG and first aid for burns appears to be lacking. The LPG delivery system should be standardized throughout countries that widely use LPG.

  18. Rogue mantle helium and neon.

    Science.gov (United States)

    Albarède, Francis

    2008-02-15

    The canonical model of helium isotope geochemistry describes the lower mantle as undegassed, but this view conflicts with evidence of recycled material in the source of ocean island basalts. Because mantle helium is efficiently extracted by magmatic activity, it cannot remain in fertile mantle rocks for long periods of time. Here, I suggest that helium with high 3He/4He ratios, as well as neon rich in the solar component, diffused early in Earth's history from low-melting-point primordial material into residual refractory "reservoir" rocks, such as dunites. The difference in 3He/4He ratios of ocean-island and mid-ocean ridge basalts and the preservation of solar neon are ascribed to the reservoir rocks being stretched and tapped to different extents during melting.

  19. Helium release during shale deformation: Experimental validation

    Science.gov (United States)

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

    2016-07-01

    This work 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 measured 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.

  20. Pierre Gorce working on a helium pump.

    CERN Multimedia

    1975-01-01

    This type of pump was designed by Mario Morpurgo, to circulate liquid helium in superconducting magnets wound with hollow conductors. M. Morpurgo, Design and construction of a pump for liquid helium, CRYIOGENICS, February 1977, p. 91

  1. The cosmic production of Helium

    CERN Document Server

    Jiménez, R; MacDonald, J; Gibson, B K; Jimenez, Raul; Flynn, Chris; Donald, James Mac; Gibson, Brad K.

    2003-01-01

    We estimate the cosmic production rate of helium relative to metals ($\\Delta Y/\\Delta Z$) using K dwarf stars in the Hipparcos catalog with accurate spectroscopic metallicities. The best fitting value is $\\Delta Y/\\Delta Z=2.1 \\pm 0.4$ at the 68% confidence level. Our derived value agrees with determinations from HII regions and with theoretical predictions from stellar yields with standard assumptions for the initial mass function. The amount of helium in stars determines how long they live and therefore how fast they will enrich the insterstellar medium with fresh material.

  2. Absolute calibration of TFTR helium proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, J.D.; Diesso, M.; Jassby, D.; Johnson, L.; McCauley, S.; Munsat, T.; Roquemore, A.L. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Barnes, C.W. [Princeton Univ., NJ (United States). Plasma Physics Lab.]|[Los Alamos National Lab., NM (United States); Loughlin, M. [Princeton Univ., NJ (United States). Plasma Physics Lab.]|[JET Joint Undertaking, Abingdon (United Kingdom)

    1995-06-01

    The TFTR helium proportional counters are located in the central five (5) channels of the TFTR multichannel neutron collimator. These detectors were absolutely calibrated using a 14 MeV neutron generator positioned at the horizontal midplane of the TFTR vacuum vessel. The neutron generator position was scanned in centimeter steps to determine the collimator aperture width to 14 MeV neutrons and the absolute sensitivity of each channel. Neutron profiles were measured for TFTR plasmas with time resolution between 5 msec and 50 msec depending upon count rates. The He detectors were used to measure the burnup of 1 MeV tritons in deuterium plasmas, the transport of tritium in trace tritium experiments, and the residual tritium levels in plasmas following 50:50 DT experiments.

  3. Helium in atmospheres of binary stars

    Energy Technology Data Exchange (ETDEWEB)

    Leushin, V.V. (Rostovskij-na-Donu Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Fiziki)

    The helium abundances were obtained for 25 bright components of binary stars by model atmosphere analysis. The helium abundance for binary stars that lie on the main sequence are larger in the average than in single normal stars. The stars on the Hertzsppung - russel diagram lie at a larger distance from the zero age line than those with normal helium abundance.

  4. Helium resources of Mare Tranquillitatis

    Science.gov (United States)

    Cameron, Eugene N.

    Wisconsin Center for Space Automation and Robotics, Univ. of Wisc., Madison, Wisc. Mare Tranquillitatis, about 300000 sq km in area, is currently the most promising lunar source of He-3 for fueling fusion power plants on Earth. About 60 pct. of the mare regolith consists of particles 100 microns or less in diameter. Helium and other gases derived from the solar wind are concentrated in the fine size fractions. Studies of very small craters indicate that the average regolith exceeds 3 m in areas away from larger craters and other mare features not amenable to mining. There is no evidence of decrease of helium content of regolith and depth. Helium is known to be enriched in regoliths that are high in TiO2 content. Remote sensing indicates that about 90 pct. of Mare Tranquillitatis is covered by regolith ranging from about 6 to +7.5 pct. TiO2; inferred He contents range from 20 to at least 45 wppm total helium (7 to 18 wppb He-3). Detailed studies of craters and inferred ejecta halos displayed on high resolution photographs of the Apollo 11 and Ranger 8 areas suggest that as much as 50 pct. of the mare regolith may be physically minable, on average, with appropriate mining equipment. Assuming that the average thickness of regolith is 3 m, and that 50 pct. of the mare area is minable, the He-3 content of minable regolith containing 20 to 45 wppm total He is estimated at about 94,000 tonnes.

  5. Electron impact on excited helium

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.; Zhong, Z. [Institute of Atomic and Molecular Physics, National Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun, 130023 (China); Ratnavelu, K. [Department of Mathematics, University of Malaya, 59100, Kuala Lumpur (Malaysia); McCarthy, I.E. [School of Physical Sciences, The Flinders University of South Australia, GPO Box 2100, SA 5001 (Australia)

    1998-12-14

    Differential cross sections, integrated cross sections and ionization cross sections for electron scattering on the metastable level 2 {sup 3}S of helium are calculated at intermediate energies and compared with experimental measurements and other theoretical calculations. The method used is the coupled-channels optical method with an ab initio complex polarization potential. (author). Letter-to-the-editor.

  6. Simplicity works for superfluid helium

    Energy Technology Data Exchange (ETDEWEB)

    Bowley, Roger [University of Nottingham, Nottingham (United Kingdom)

    2000-02-01

    The famous philosopher Karl Popper once said that ''science is the art of systematic oversimplification''. Indeed, when faced with a new puzzle the trick is to simplify it without losing the essential physics - something that is easier said than done. However, this approach has paid off recently in low-temperature physics. Last year Richard Packard, Seamus Davis and co-workers at the University of California at Berkeley encountered a puzzling new phenomenon in superfluid helium-3, a quantum fluid that remains a liquid close to absolute zero and exhibits unusual properties such as the ability to flow without friction (A Machenkov et al. 1999 Phys. Rev. Lett. 83 3860). Previous experiments had revealed that certain effects in liquid helium are analogous to effects observed in superconductors, materials that lose all resistance to electric current at low temperatures. When the Berkeley researchers connected two reservoirs of superfluid helium-3, the superfluid flowed back and forth through apertures that formed a ''weak link'' between the two containers. This behaviour is similar to the oscillatory current of electrons that can flow across an insulating gap separating two superconductors - a device that is known as a Josephson junction. What was puzzling about the Berkeley results was that the helium-3 had two different stable configurations, both of which behaved in an unconventional way compared with a Josephson junction. This puzzle has now been solved independently by Sidney Yip at the National Center for Theoretical Sciences in Taiwan, and by Janne Viljas and Erkki Thuneberg at the Helsinki University of Technology in Finland (Phys. Rev. Lett. 1999 83 3864 and 3868). In this article the author describes the latest research on superfluid helium. (UK)

  7. Precision spectroscopy of the helium atom

    Institute of Scientific and Technical Information of China (English)

    Shui-ming HU; Zheng-Tian LU; Zong-Chao YAN

    2009-01-01

    Persistent efforts in both theory and experiment have yielded increasingly precise understanding of the helium atom. Because of its simplicity, the helium atom has long been a testing ground for relativistic and quantum electrodynamic effects in few-body atomic systems theoretically and experimentally.Comparison between theory and experiment of the helium spectroscopy in ls2p3pJ can potentially extract a very precise value of the fine structure constant a. The helium atom can also be used to explore exotic nuclear structures. In this paper, we provide a brief review of the recent advances in precision calculations and measurements of the helium atom.

  8. Novolak PF resins prepared from phenol liquefied Cryptomeria japonica and used in manufacturing moldings.

    Science.gov (United States)

    Lee, Wen-Jau; Chen, Yi-Chun

    2008-10-01

    The wood of Japanese cedar (Cryptomeria japonica) was liquefied in phenol with H2SO4 and HCl as catalysts. The liquefied wood was reacted with formalin to prepare the novolak PF resin. The results showed that the reaction of liquefied Japanese cedar with formalin was an exothermic reaction, and formed a solid-like resin without extra heating. Two novolak PF resins were prepared from the liquefied wood which were identified as SF and CF that using the liquefied wood with H2SO4 and HCl as catalyst respectively. The novolak PF powder displayed thermo-melting characteristic. The resins of SF and CF had weight average molecular weight of 3638 and 3941 respectively and melting temperature of 149.4 degrees C and 127.5 degrees C respectively. Both of the novolak resins could be used to make moldings with good performance by mixing the novolak resin with wood powder, hardener and zinc stearate at the weight ratio of 60:30:10:1 and hot-pressed under 200 degrees C for 10min.

  9. HeREF-2003 : Helium Refrigeration Techniques

    CERN Multimedia

    2003-01-01

    CERN Technical Training 2003: Learning for the LHC ! Theory, Technology, Maintenance and Control of Helium Refrigerators HeREF-2003 is a course in the framework of the 2002 Technical Training Programme, that will provide a complete introduction to Helium refrigeration, with a practical approach to theory, technology, maintenance and control of Helium refrigeration installations. Theoretical aspects and equations will be limited to a minimum. HeREF-2003 targets an audience of technicians and operators of Helium refrigeration plants at CERN, as well as physicists and engineers needing an overview of current Helium refrigeration techniques. HeREF-2003 will address, among other, issues related to component technology, installation maintenance, process control and Helium purity. A commented visit to a couple of CERN Helium refrigeration or liquefaction plants will also take place. • Duration: 7 half days (4 mornings and 3 afternoons), 6-10 October, 2003 • Cost per participant: 500.- CHF ...

  10. HeREF-2003: Helium Refrigeration Techniques

    CERN Multimedia

    2003-01-01

    CERN Technical Training 2003: Learning for the LHC ! Theory, Technology, Maintenance and Control of Helium Refrigerators HeREF-2003 is a course in the framework of the 2002 Technical Training Programme, that will provide a complete introduction to Helium refrigeration, with a practical approach to theory, technology, maintenance and control of Helium refrigeration installations. Theoretical aspects and equations will be limited to a minimum. HeREF-2003 targets an audience of technicians and operators of Helium refrigeration plants at CERN, as well as physicists and engineers needing an overview of current Helium refrigeration techniques. HeREF-2003 will address, among other, issues related to component technology, installation maintenance, process control and Helium purity. A commented visit to a couple of CERN Helium refrigeration or liquefaction plants will also take place. Duration: 7 half days (4 mornings and 3 afternoons), 6-10 October, 2003 Cost per participant: 500.- CHF Language: Bilingual English...

  11. Carbon Shell or Core Ignitions in White Dwarfs Accreting from Helium Stars

    CERN Document Server

    Brooks, Jared; Schwab, Josiah; Paxton, Bill

    2016-01-01

    White dwarfs accreting from helium stars can stably burn at the accreted rate and avoid the challenge of mass loss associated with unstable Helium burning that is a concern for many Type Ia supernovae scenarios. We study binaries with helium stars of mass $1.25 M_\\odot\\le M_{\\rm{He}} \\le 1.8 M_\\odot$, which have lost their hydrogen rich envelopes in an earlier common envelope event and now orbit with periods ($P_{\\rm orb}$) of several hours with non-rotating $0.84$ and $1.0 M_\\odot$ C/O WDs. The helium stars fill their Roche lobes (RLs) after exhaustion of central helium and donate helium on their thermal timescales (${\\sim}10^5$yr). As shown by others, these mass transfer rates coincide with the steady helium burning range for WDs, and grow the WD core up to near the Chandrasekhar mass ($M_{\\rm Ch}$) and a core carbon ignition. We show here, however, that many of these scenarios lead to an ignition of hot carbon ashes near the outer edge of the WD and an inward going carbon flame that does not cause an explo...

  12. Learning Equipment for the Flammability Limits of Liquefied Petroleum Gas

    Directory of Open Access Journals (Sweden)

    Siriratchanee Sirisawat

    2012-01-01

    Full Text Available Problem statement: This article was developing learning equipment for flammability limit behavior which designed for study the relation of Liquefied Petroleum Gas (LPG and combustion. The equipment can be use as an instructional media for obviously experiment of combustion. Approach: The test chamber was designed by using the stainless as a structure. The mirror with safety film was used for safety purpose to the tester. The mirror was the additional equipment for the ignition vision. The size of test chamber was 40×25×20 cm. The top of chamber can be opened when the ignition was occurred to reduce the inner pressure that can break the mirror or can be a cause of damage to other parts. The 2 of stainless plates with the size of 15×40 cm. were used and the hinges were attached at the upper edges of the chamber from both sides. The metal was closely attached at the chamber edge to reduce the leak of fuel to outer environment. The bottom structure of the chamber installs the control mainboard of electronics system and motor. The control of heat gain system inside the heat chamber. Results: The test chamber is designed to demonstrate the ignition. So, the size has to be suitably designed and large enough for convenience in monitoring. It can be seen that when the test is conducted in a real system, the result is extremely differed from the theory. The reason is the experimentation by the theory using the cup burner or a cylindrical glass cup. This cup has an outside diameter of 28 mm. and around the cup tunnel has an inside diameter of 8.5 or 9.5 cm with 53.5 cm. of height. The ratios of both testing equipments are extremely differed, so there is an opportunity that the accuracy is highly shifted. Conclusion: The test chamber shows that the flammability limit of LPG vary with temperature and can be compare with burgess-wheeler law. This law mentioned “LFL and UFL is relative with the chemical in Paraffin Hydrocarbon (Alkane Group in

  13. Liquefied natural gas: a harbor plan; Plano diretor portuario para o gas natural liquefeito

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Aluisio de Souza; Baitelo, Ricardo Lacerda [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica; Rego, Erik Eduardo [Excelencia Energetica Consultoria Empresarial Ltda., Sao Paulo, SP (Brazil); Rosim, Sidney Olivieri [Rosim e Papaleo Consultoria e Participacoes Ltda., Sao Paulo, SP (Brazil)

    2008-07-01

    The objective of this article is to present the structuring of a port directing plan for the liquefied natural gas. In this sense, an integrated approach between the applied logistic and the requested market conditions was used. For the large distances transportation of liquefied natural gas, the marine modal must attain technical requirements that are not usual in the port routine. Apart from the proper dimensioning of the naval fleet in order to maximize the transported load, providing the optimization of the economic distance, the entire port infra-structure is planned for the reception of liquefied natural gas, in order to attend the physical peculiarities as well as security aspects of extreme importance. The selection of the studied local was motivated by the fuel supply shortage suffered by the country, especially in the northeast region, which owns already installed thermal units in need of the fuel supply to be operated. (author)

  14. Confined helium on Lagrange meshes

    CERN Document Server

    Baye, Daniel

    2015-01-01

    The Lagrange-mesh method has the simplicity of a calculation on a mesh and can have the accuracy of a variational method. It is applied to the study of a confined helium atom. Two types of confinement are considered. Soft confinements by potentials are studied in perimetric coordinates. Hard confinement in impenetrable spherical cavities is studied in a system of rescaled perimetric coordinates varying in [0,1] intervals. Energies and mean values of the distances between electrons and between an electron and the helium nucleus are calculated. A high accuracy of 11 to 15 significant figures is obtained with small computing times. Pressures acting on the confined atom are also computed. For sphere radii smaller than 1, their relative accuracies are better than $10^{-10}$. For larger radii up to 10, they progressively decrease to $10^{-3}$, still improving the best literature results.

  15. Elusive structure of helium trimers

    CERN Document Server

    Stipanović, Petar; Boronat, Jordi

    2016-01-01

    Over the years many He-He interaction potentials have been developed, some very sophisticated, including various corrections beyond Born-Oppenheimer approximation. Most of them were used to predict properties of helium dimers and trimers, examples of exotic quantum states, whose experimental study proved to be very challenging. Recently, detailed structural properties of helium trimers were measured for the first time, allowing a comparison with theoretical predictions and possibly enabling the evaluation of different interaction potentials. The comparisons already made included adjusting the maxima of both theoretical and experimental correlation functions to one, so the overall agreement between theory and experiment appeared satisfactory. However, no attempt was made to evaluate the quality of the interaction potentials used in the calculations. In this work, we calculate the experimentally measured correlation functions using both new and old potentials, compare them with experimental data and rank the po...

  16. Rapidly pulsed helium droplet source

    Energy Technology Data Exchange (ETDEWEB)

    Pentlehner, Dominik; Riechers, Ricarda; Dick, Bernhard; Slenczka, Alkwin [Institute for Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg (Germany); Even, Uzi; Lavie, Nachum; Brown, Raviv; Luria, Kfir [Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv (Israel)

    2009-04-15

    A pulsed valve connected to a closed-cycle cryostat was optimized for producing helium droplets. The pulsed droplet beam appeared with a bimodal size distribution. The leading part of the pulse consists of droplets suitable for doping with molecules. The average size of this part can be varied between 10{sup 4} and 10{sup 6} helium atoms, and the width of the distribution is smaller as compared to a continuous-flow droplet source. The system has been tested in a single pulse mode and at repetition rates of up to 500 Hz with almost constant intensity. The droplet density was found to be increased by more than an order of magnitude as compared to a continuous-flow droplet source.

  17. Helium atom scattering from surfaces

    CERN Document Server

    1992-01-01

    High resolution helium atom scattering can be applied to study a number of interesting properties of solid surfaces with great sensitivity and accuracy. This book treats in detail experimental and theoretical aspects ofthis method as well as all current applications in surface science. The individual chapters - all written by experts in the field - are devoted to the investigation of surface structure, defect shapes and concentrations, the interaction potential, collective and localized surface vibrations at low energies, phase transitions and surface diffusion. Over the past decade helium atom scattering has gained widespread recognitionwithin the surface science community. Points in its favour are comprehensiveunderstanding of the scattering theory and the availability of well-tested approximation to the rigorous theory. This book will be invaluable to surface scientists wishing to make an informed judgement on the actual and potential capabilities of this technique and its results.

  18. Particle detection using superfluid helium

    Energy Technology Data Exchange (ETDEWEB)

    Bandler, S.R.; Lanou, R.E.; Maris, H.J.; More, T.; Porter, F.S.; Seidel, G.M.; Torii, R.

    1991-01-01

    We have observed 5 MeV {alpha} particles stopped in volumes-up to two liters of liquid helium at 70 mK. A fraction of the kinetic energy of an {alpha} particle is converted to elementary excitations (rotons and phonons), which progagate ballistically in isotopically pure {sup 4}He below 0.1 K. Most of these excitations have sufficient energy to evaporate helium atoms on hitting a free surface. The evaporated helium atoms can be detected calorimetrically when adsorbed on a thin silicon wafer ({approximately}1.7 g, 35 cm{sup 2}) suspended above the liquid. Temperature changes of the silicon are measured with a NTD germanium bolometer. For the geometry studied the observed temperature change of the silicon resulting from an {alpha} event in the liquid is approximately 5% of the temperature rise from an {alpha} hitting the silicon directly. The implications of these measurements will be discussed as they relate to the possible construction of a large scale detector of solar neutrinos.

  19. Particle detection using superfluid helium

    Energy Technology Data Exchange (ETDEWEB)

    Bandler, S.R.; Lanou, R.E.; Maris, H.J.; More, T.; Porter, F.S.; Seidel, G.M.; Torii, R.

    1991-12-31

    We have observed 5 MeV {alpha} particles stopped in volumes-up to two liters of liquid helium at 70 mK. A fraction of the kinetic energy of an {alpha} particle is converted to elementary excitations (rotons and phonons), which progagate ballistically in isotopically pure {sup 4}He below 0.1 K. Most of these excitations have sufficient energy to evaporate helium atoms on hitting a free surface. The evaporated helium atoms can be detected calorimetrically when adsorbed on a thin silicon wafer ({approximately}1.7 g, 35 cm{sup 2}) suspended above the liquid. Temperature changes of the silicon are measured with a NTD germanium bolometer. For the geometry studied the observed temperature change of the silicon resulting from an {alpha} event in the liquid is approximately 5% of the temperature rise from an {alpha} hitting the silicon directly. The implications of these measurements will be discussed as they relate to the possible construction of a large scale detector of solar neutrinos.

  20. DYNAMIC BEHAVIOR OF BURIED BEND WITH THRUST RESTRAINT IN LIQUEFYING GROUND

    Science.gov (United States)

    Kawabata, Toshinori; Sawada, Yutaka; Mohri, Yoshiyuki; Ling, Hoe I.

    In this study, a shaking table test was carried out in order to discuss the dynamic behavior for the bend of pressure pipeline with a concrete block and thrust restraints using geogrids or gravels in liquefying ground. As a result, it was revealed that the concrete block was largely moved and the relative displacement between the bend and the adjacent pipe became large. On the other hand, it was proved that geogrids and gravels were very effective for the lateral resistance in liquefying ground. In addition, the relative displacement was small because of the same difference between the bend and the adjacent pipe.

  1. Liquefied Gaseous Fuels Safety and Environmental Control Assessment Program: second status report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-10-01

    This document is arranged in three volumes and reports on progress in the Liquefied Gaseous Fuels (LGF) Safety and Environmental Control Assessment Program made in fiscal Year (FY)-1979 and early FY-1980. Volume 3 contains reports from 6 government contractors on LPG, anhydrous ammonia, and hydrogen energy systems. Report subjects include: simultaneous boiling and spreading of liquefied petroleum gas (LPG) on water; LPG safety research; state-of-the-art of release prevention and control technology in the LPG industry; ammonia: an introductory assessment of safety and environmental control information; ammonia as a fuel, and hydrogen safety and environmental control assessment.

  2. Removal of organic contaminants from water or wastewater with liquefied gases

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This study utilized liquefied gases (LG) as extractant to remove various organic contaminants including halogenated hydrocarbons and phenols as well as aromatic compounds from aqueousmatrices. Orthogonal experiments were performed to optimize theoperating conditions such as temperature, co-solvents and so on.Under favorable conditions, high removal efficiencies can bereadily achieved for a great number of representative model organiccontaminants, the removal efficiencies for most of the hydrophobiccontaminants were greater than 90% in a single extraction stage.Tentative effort was also done for the removal of extractedcontaminants from recycled liquefied gases.

  3. 76 FR 33746 - Freeport LNG Development, L.P.; Application for Blanket Authorization To Export Liquefied Natural...

    Science.gov (United States)

    2011-06-09

    ... Freeport LNG Development, L.P.; Application for Blanket Authorization To Export Liquefied Natural Gas..., 2011, by Freeport LNG Development, L.P. (Freeport LNG), requesting blanket authorization to export liquefied natural gas (LNG) that previously had been imported into the United States from foreign sources...

  4. 33 CFR 165.1709 - Security Zones: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG...

    Science.gov (United States)

    2010-07-01

    ... Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. 165.1709 Section...: Liquefied Natural Gas Tanker Transits and Operations at Phillips Petroleum LNG Pier, Cook Inlet, AK. (a... navigable waters within a 1000-yard radius of the Liquefied Natural Gas (LNG) tankers during their...

  5. 77 FR 66454 - Gulf LNG Liquefaction Company, LLC; Application for Long-Term Authorization To Export Liquefied...

    Science.gov (United States)

    2012-11-05

    ... LNG Liquefaction Company, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas... on August 31, 2012, by Gulf LNG Liquefaction Company, LLC (GLLC), requesting long-term, multi... liquefied natural gas (LNG), the equivalent of approximately 547.5 billion cubic feet (Bcf) of natural...

  6. 78 FR 17189 - Trunkline LNG Export, LLC; Application for Long-Term Authorization to Export Liquefied Natural...

    Science.gov (United States)

    2013-03-20

    ... Trunkline LNG Export, LLC; Application for Long-Term Authorization to Export Liquefied Natural Gas Produced... January 10, 2013, by Trunkline LNG Export, LLC (TLNG Export), requesting long-term, multi-contract authorization to export domestically produced liquefied natural gas (LNG) in an amount up to of 15...

  7. 77 FR 63806 - Southern LNG Company, L.L.C.; Application for Long-Term Authorization To Export Liquefied Natural...

    Science.gov (United States)

    2012-10-17

    ... Southern LNG Company, L.L.C.; Application for Long-Term Authorization To Export Liquefied Natural Gas... on August 31, 2012, by Southern LNG Company, L.L.C. (Southern LNG), requesting long-term, multi-contract authorization to export up to 4 million tons per annum (mtpa) of liquefied natural gas (LNG),...

  8. 75 FR 13755 - Freeport LNG Development, L.P.; Application To Amend Blanket Authorization To Export Liquefied...

    Science.gov (United States)

    2010-03-23

    ... Freeport LNG Development, L.P.; Application To Amend Blanket Authorization To Export Liquefied Natural Gas... application filed on March 4, 2010, by Freeport LNG Development, L.P. (Freeport LNG), requesting an amendment to its blanket authorization to export liquefied natural gas (LNG) granted by DOE/FE on May 28,...

  9. 78 FR 38024 - Magnolia LNG, LLC; Liquefied Natural Gas Limited; Notice of Intent To Prepare an Environmental...

    Science.gov (United States)

    2013-06-25

    ... Energy Regulatory Commission Magnolia LNG, LLC; Liquefied Natural Gas Limited; Notice of Intent To...) that will discuss the environmental impacts of the Magnolia Liquefied Natural Gas Project (Magnolia LNG Project) involving construction and operation of facilities by Magnolia LNG, LLC (Magnolia) in...

  10. 77 FR 4028 - Orders Granting, Amending and Vacating Authority To Import and Export Natural Gas and Liquefied...

    Science.gov (United States)

    2012-01-26

    ... Granting, Amending and Vacating Authority To Import and Export Natural Gas and Liquefied Natural Gas FE Docket Nos. Gas Natural Caxitlan, S. DE R.L 11-147-NG Jordan Cove Energy Project, L.P 11-127-LNG Irving..., amending and vacating authority to import and export natural gas and liquefied natural gas. These......

  11. 78 FR 4401 - Orders Granting Authority To Import and Export Natural Gas, To Import and Export Liquefied...

    Science.gov (United States)

    2013-01-22

    ... Granting Authority To Import and Export Natural Gas, To Import and Export Liquefied Natural Gas, and... export natural gas and liquefied natural gas. These orders are summarized in the attached appendix and... ENERGY INC 12-124-NG GLACIAL NATURAL GAS, INC 12-125-NG YANKEE GAS SERVICES COMPANY 12-129-NG......

  12. 75 FR 62510 - Chevron U.S.A. Inc.; Application for Blanket Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2010-10-12

    ... U.S.A. Inc.; Application for Blanket Authorization To Export Liquefied Natural Gas AGENCY: Office of..., 2010, by Chevron U.S.A. Inc. (Chevron), requesting blanket authorization to export liquefied natural... up to the equivalent of 72 billion cubic feet (Bcf) of natural gas on a short-term or spot...

  13. 78 FR 19696 - Orders Granting Authority To Import and Export Natural Gas, To Import Liquefied Natural Gas, To...

    Science.gov (United States)

    2013-04-02

    ... Granting Authority To Import and Export Natural Gas, To Import Liquefied Natural Gas, To Export Liquefied Natural Gas and Vacating Prior Authority During December 2012 FE Docket Nos. DIAMOND CAPITAL INTERNATIONAL... during December 2012, it issued orders granting authority to import and export natural gas and......

  14. 77 FR 12274 - Orders Granting Authority To Import and Export Natural Gas and Liquefied Natural Gas During...

    Science.gov (United States)

    2012-02-29

    ... Orders Granting Authority To Import and Export Natural Gas and Liquefied Natural Gas During January 2012... 2012, it issued Orders granting authority to import and export natural gas and liquefied natural gas.... DOMINION COVE POINT LNG, LP 11-98-LNG ENERGY PLUS NATURAL GAS LLC 11-155-NG BROOKFIELD ENERGY......

  15. 77 FR 33446 - Jordan Cove Energy Project, L.P.; Application for Long-Term Authorization to Export Liquefied...

    Science.gov (United States)

    2012-06-06

    ... Cove Energy Project, L.P.; Application for Long-Term Authorization to Export Liquefied Natural Gas Produced From Domestic and Canadian Natural Gas Resources to Non-Free Trade Agreement Countries for a 25..., multi-contract authorization to export as liquefied natural gas (LNG) both natural gas...

  16. 78 FR 21349 - Orders Granting Authority To Import and Export Natural Gas, To Export Liquefied Natural Gas, To...

    Science.gov (United States)

    2013-04-10

    ... Granting Authority To Import and Export Natural Gas, To Export Liquefied Natural Gas, To Export Compressed Natural Gas, Vacating Prior Authority and Denying Request for Rehearing During January 2013 ] FE Docket... January 2013, it issued orders granting authority to import and export natural gas and liquefied......

  17. 77 FR 31838 - Notice of Orders Granting Authority to Import and Export Natural Gas and Liquefied Natural Gas...

    Science.gov (United States)

    2012-05-30

    ... of Orders Granting Authority to Import and Export Natural Gas and Liquefied Natural Gas During April..., it issued Orders granting authority to import and export natural gas and liquefied natural gas. These... Capital International, LLC....... 12-33-NG Phillips 66 Company 12-34-NG Northwest Natural Gas Company......

  18. 78 FR 46581 - Orders Granting Authority To Import and Export Natural Gas, and To Import Liquefied Natural Gas...

    Science.gov (United States)

    2013-08-01

    ... Granting Authority To Import and Export Natural Gas, and To Import Liquefied Natural Gas During June 2013... authority to import and export natural gas and to import liquefied natural gas. These orders are summarized... of Fossil Energy, Office of Natural Gas Regulatory Activities, Docket Room 3E-033,......

  19. 78 FR 53739 - Orders Granting Authority To Import and Export Natural Gas, To Import and Export Liquefied...

    Science.gov (United States)

    2013-08-30

    ... Granting Authority To Import and Export Natural Gas, To Import and Export Liquefied Natural Gas and... export natural gas, to import and export liquefied natural gas and to vacate prior authority. These... ENERGY) 13-83-LNG STANDARD NATURAL GAS, INC.) 13-81-LNG CASTLETON COMMODITIES CANADA LP) 1...

  20. 78 FR 65304 - Orders Granting Authority To Import and Export Natural Gas, and To Import and Export Liquefied...

    Science.gov (United States)

    2013-10-31

    ... Granting Authority To Import and Export Natural Gas, and To Import and Export Liquefied Natural Gas During... issued orders granting authority to import and export natural gas, and to import and export liquefied natural gas. These orders are summarized in the attached appendix and may be found on the FE Web site...

  1. 78 FR 35014 - Orders Granting Authority to Import and Export Natural Gas, and to Import Liquefied Natural Gas...

    Science.gov (United States)

    2013-06-11

    ... Granting Authority to Import and Export Natural Gas, and to Import Liquefied Natural Gas During April 2013... natural gas and to import liquefied natural gas. These orders are summarized in the attached appendix and... INC 13-41-NG CASCADE NATURAL GAS CORPORATION 13-43-NG ENCANA MARKETING (USA) INC 13-44-NG......

  2. 77 FR 19277 - Orders Granting Authority To Import and Export Natural Gas and Liquefied Natural Gas During...

    Science.gov (United States)

    2012-03-30

    ... Granting Authority To Import and Export Natural Gas and Liquefied Natural Gas During February 2012 FE... 2012, it issued Orders granting authority to import and export natural gas and liquefied natural gas..., ULC 12-13-NG ENCANA NATURAL GAS INC 11-163-NG ALCOA INC 12-11-NG JPMORGAN LNG CO 12-15-LNG CNE......

  3. 78 FR 44940 - Orders Granting Authority To Import and Export Natural Gas, and To Import and Export Liquefied...

    Science.gov (United States)

    2013-07-25

    ... Granting Authority To Import and Export Natural Gas, and To Import and Export Liquefied Natural Gas During May 2013 FE DOCKET NOS. CASCADE NATURAL GAS CORPORATION........ 12-179-NG CASCADE NATURAL GAS... orders granting authority to import and export natural gas and to import and export liquefied......

  4. 76 FR 34212 - Lake Charles Exports, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2011-06-13

    ... Charles Exports, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas AGENCY...-contract authorization to export up to 15 million metric tons per annum (mmtpa) of domestic natural gas as liquefied natural gas (LNG) for a 25-year period, commencing the earlier of the date of first export or...

  5. 33 CFR 165.502 - Safety and Security Zone; Cove Point Liquefied Natural Gas Terminal, Chesapeake Bay, Maryland.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety and Security Zone; Cove Point Liquefied Natural Gas Terminal, Chesapeake Bay, Maryland. 165.502 Section 165.502 Navigation and... Areas Fifth Coast Guard District § 165.502 Safety and Security Zone; Cove Point Liquefied Natural...

  6. 49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

    Science.gov (United States)

    2010-10-01

    ...-liquefied (permanent) compressed gases in UN pressure receptacles. 173.302b Section 173.302b Transportation... (permanent) compressed gases in UN pressure receptacles. (a) General. A cylinder filled with a non-liquefied gas must be offered for transportation in UN pressure receptacles subject to the requirements in...

  7. Investigations of levitated helium drops

    Science.gov (United States)

    Whitaker, Dwight Lawrence

    1999-11-01

    We report on the development of two systems capable of levitating drops of liquid helium. Helium drops of ˜20 mum have been levitated with the radiation pressure from two counter-propagating Nd:YAG laser beams. Drops are produced with a submerged piezoelectric transducer, and could be held for up to three minutes in our optical trap. Calculations show that Brillouin and Raman scattering of the laser light in the liquid helium produces a negligible rate of evaporation of the drop. Evaporation caused by the enhanced vapor pressure of the curved drop surfaces appears to be a significant effect limiting the drop lifetimes. Helium drops as large as 2 cm in diameter have been suspended in the earth's gravitational field with a magnetic field. A commercial superconducting solenoid provides the necessary field, field-gradient product required to levitate the drops. Drops are cooled to 0.5 K with a helium-3 refrigerator, and can be held in the trap indefinitely. We have found that when two or more drops are levitated in the same magnetic trap, the drops often remain in a state of apparent contact without coalescing. This effect is a result of the evaporation of liquid from between the two drops, and is found to occur only for normal fluid drops. We can induce shape oscillations in charged, levitated drops with an applied ac electric field. We have measured the resonance frequencies and damping rates for the l = 2 mode of oscillation as function of temperature. We have also developed a theory to describe the small amplitude shape oscillations of a He II drop surrounded by its saturated vapor. In our theory, we have considered two sets of boundary conditions---one where the drop does not evaporate and another in which the liquid and vapor are in thermodynamic equilibrium. We have found that both solutions give a frequency that agrees well with experiment, but that the data for the damping rate agree better with the solution without evaporation.

  8. Report of working committee 3 ''liquefied gases''; Rapport du comite de travail 3 ''gaz liquefies''

    Energy Technology Data Exchange (ETDEWEB)

    Baudino, M.

    2000-07-01

    Working Committee 3's report concerns the evolution of the liquefied gas industry: both liquefied natural gas (LNG) and liquefied petroleum gases (LPG). Given the current state of the LNG market the Committee decided to concentrate on this area in particular. A number of aspects have been identified which the Committee has been looking at, while others have been given to Study Groups set up specifically for the purpose. The first aspects regard: - the development of LNG and LPG, new installations, future chains and relevant statistical data; - the role of LNG and LPG in starting up a gas industry; - operating and technological improvements in the LNG industry; - energy savings, cold utilization and reduction of CO{sub 2} emissions. The Study Groups which were set up dealt with the following subjects: Technological and Economical Developments for cost Reduction of LNG/LPG Facilities. Small Scale LNG Projects and Modular Systems. LNG/LPG Peak Shaving and Satellite Plants. LNG versus Pipeline Infrastructure. (author)

  9. Assembly of cell-laden hydrogel fiber into non-liquefied and liquefied 3D spiral constructs by perfusion-based layer-by-layer technique.

    Science.gov (United States)

    Sher, Praveen; Oliveira, Sara M; Borges, João; Mano, João F

    2015-01-06

    In this work, three-dimensional (3D) self-sustaining, spiral-shaped constructs were produced through a combination of ionotropic gelation, to form cell-encapsulated alginate fibers, and a perfusion-based layer-by-layer (LbL) technique. Single fibers were assembled over cylindrical molds by reeling to form spiral shapes, both having different geometries and sizes. An uninterrupted nanometric multilayer coating produced by a perfusion-based LbL technique, using alginate and chitosan, generated stable 3D spiral-shaped macrostructures by gripping and affixing the threads together without using any crosslinking/binding agent. The chelation process altered the internal microenvironment of the 3D construct from the solid to the liquefied state while preserving the external geometry. L929 cell viability by MTS and dsDNA quantification favor liquefied 3D constructs more than non-liquefied ones. The proposed technique setup helps us to generate complex polyelectrolyte-based 3D constructs for tissue engineering applications and organ printing.

  10. Critical Landau velocity in helium nanodroplets.

    Science.gov (United States)

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

    2013-10-11

    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.

  11. Behaviour of helium after implantation in molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Viaud, C. [Commissariat a l' Energie Atomique (CEA), Cadarache (France)], E-mail: viaud@dircad.cea.fr; Maillard, S.; Carlot, G.; Valot, C. [Commissariat a l' Energie Atomique (CEA), Cadarache (France); Gilabert, E. [Chimie Nucleaire Analytique and Bio-environnementale (CNAB), Gradignan (France); Sauvage, T. [CEMHTI-CNRS, Orleans (France); Peaucelle, C.; Moncoffre, N. [Institut de Physique Nucleaire de Lyon (IPNL), Lyon (France)

    2009-03-31

    This study deals with the behaviour of helium in a molybdenum liner dedicated to the retention of fission products. More precisely this work contributes to evaluate the release of implanted helium when the gas has precipitated into nanometric bubbles close to the free surface. A simple model dedicated to calculate the helium release in such a condition is presented. The specificity of this model lays on the assumption that the gas is in equilibrium with a simple distribution of growing bubbles. This effort is encouraging since the calculated helium release fits an experimental dataset with a set of parameters in good agreement with the literature.

  12. Liquefaction of corn stover and preparation of polyester from the liquefied polyol.

    Science.gov (United States)

    Yu, Fei; Liu, Yuhuan; Pan, Xuejun; Lin, Xiangyang; Liu, Chengmei; Chen, Paul; Ruan, Roger

    2006-01-01

    This research investigated a novel process to prepare polyester from corn stover through liquefaction and crosslinking processes. First, corn stover was liquefied in organic solvents (90 wt% ethylene glycol and 10 wt% ethylene carbonate) with catalysts at moderate temperature under atmospheric pressure. The effect of liquefaction temperature, biomass content, and type of catalyst, such as H2SO4, HCl, H3PO4, and ZnCl2, was evaluated. Higher liquefaction yield was achieved in 2 wt% sulfuric acid, 1/4 (w/w) stover to liquefying reagent ratio; 160 degrees C temperature, in 2 h. The liquefied corn stover was rich in polyols, which can be directly used as feedstock for making polymers without further separation or purification. Second, polyester was made from the liquefied corn stover by crosslinking with multifunctional carboxylic acids and/or cyclic acid anhydrides. The tensile strength of polyester is about 5 MPa and the elongation is around 35%. The polyester is stable in cold water and organic solvents and readily biodegradable as indicated by 82% weight loss when buried in damp soil for 10 mo. The results indicate that this novel polyester could be used for the biodegradable garden mulch film production.

  13. 46 CFR 61.15-10 - Liquefied-petroleum-gas piping for heating and cooking.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Liquefied-petroleum-gas piping for heating and cooking. 61.15-10 Section 61.15-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... piping for heating and cooking. (a) Leak tests as described in paragraph (b) of this section shall...

  14. 75 FR 70350 - Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License Application

    Science.gov (United States)

    2010-11-17

    ... Maritime Administration Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License... receive and transfer natural gas from purpose-build LNG regasification vessels (LNGRVs) with a total cargo tank capacity of approximately 145,000 m\\3\\. The vessels would be equipped to vaporize LNG cargo...

  15. 76 FR 4417 - Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License Application

    Science.gov (United States)

    2011-01-25

    ... Maritime Administration Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License.... Liberty Deepwater Port would receive and transfer natural gas from purpose-built LNG regasification... equipped to vaporize LNG cargo to natural gas through onboard closed loop vaporization systems and...

  16. 75 FR 62512 - Sabine Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied...

    Science.gov (United States)

    2010-10-12

    ... Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas AGENCY... September 7, 2010, by Sabine Pass Liquefaction, LLC (Sabine Pass), requesting long-term, multi-contract... from the date of issuance of the requested authorization. Sabine Pass seeks authorization to export...

  17. 29 CFR 1910.110 - Storage and handling of liquefied petroleum gases.

    Science.gov (United States)

    2010-07-01

    ... 130 °F., except on containers provided with fixed maximum level indicators or which are filled by..., diaphragms, etc., shall be of such quality as to be resistant to the action of liquefied petroleum gas under... damage. Where soil conditions warrant, all piping shall be protected against corrosion....

  18. 78 FR 75359 - Waterway Suitability Assessment for Construction and Operation of Liquefied Gas Terminals; Orange...

    Science.gov (United States)

    2013-12-11

    ... regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). Public... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF HOMELAND SECURITY Coast Guard Waterway Suitability Assessment for Construction and Operation of Liquefied...

  19. Some insights in novel risk modeling of liquefied natural gas carrier maintenance operations

    Science.gov (United States)

    Nwaoha, T. C.; John, Andrew

    2016-06-01

    This study discusses the analysis of various modeling approaches and maintenance techniques applicable to the Liquefied Natural Gas (LNG) carrier operations in the maritime environment. Various novel modeling techniques are discussed; including genetic algorithms, fuzzy logic and evidential reasoning. We also identify the usefulness of these algorithms in the LNG carrier industry in the areas of risk assessment and maintenance modeling.

  20. Helium liquefaction with a commercial 4 K Gifford-McMahon cryocooler

    Science.gov (United States)

    Schmidt-Wellenburg, P.; Zimmer, O.

    2006-11-01

    This paper describes helium liquefaction using a commercial cryocooler with 1.5 W cooling power at 4.2 K (Sumitomo model RDK415D with compressor CSW-71D, consuming 6.5 kW electrical power), equipped with heat exchangers for precooling the incoming gas. No additional cooling power of cryoliquids or additional Joule-Thomson stages were utilized. Measurements of the pressure dependence of the liquefaction rate were performed. A maximum value of 83.9 g/h was obtained for 2.25 bar stabilized input pressure. Including the time needed to cool the liquefied helium to 4.2 K at 1 bar after filling the bottle connected to the cold head, and correcting for heat screen influences, this results in a net liquefaction rate of 67.7 g/h. Maintaining a pressure close to 1 bar above the bath during liquefaction, a rate of 55.7 g/h was obtained. The simple design enables many applications of the apparatus.

  1. Helium stratification in HD 145792: a new Helium strong star

    CERN Document Server

    Catanzaro, G

    2007-01-01

    In this paper we report on the real nature of the star HD 145792, classified as He weak in {\\it ``The General Catalogue of Ap and Am stars''}. By means of FEROS@ESO1.52m high resolution spectroscopic data, we refined the atmospheric parameters of the star, obtaining: T$_{\\rm eff}$ = 14400 $\\pm$ 400 K, $\\log g$ = 4.06 $\\pm$ 0.08 and $\\xi$ = 0 $^{+0.6}$ km s$^{-1}$. These values resulted always lower than those derived by different authors with pure photometric approaches. Using our values we undertook an abundance analysis with the aim to derive, for the first time, the chemical pattern of the star's atmosphere. For metals a pure LTE synthesis (ATLAS9 and SYNTHE) has been used, while for helium a hybrid approach has been preferred (ATLAS9 and SYNSPEC). The principal result of our study is that HD 145792 belongs to He strong class contrary to the previous classification. Moreover, helium seems to be vertically stratified in the atmosphere, decreasing toward deepest layers. For what that concerns metals abundanc...

  2. Helium II level measurement techniques

    Science.gov (United States)

    Celik, D.; Hilton, D. K.; Zhang, T.; Van Sciver, S. W.

    2001-05-01

    In this paper, a survey of cryogenic liquid level measurement techniques applicable to superfluid helium (He II) is given. The survey includes both continuous and discrete measurement techniques. A number of different probes and controlling circuits for this purpose have been described in the literature. They fall into one of the following categories: capacitive liquid level gauges, superconducting wire liquid level gauges, thermodynamic (heat transfer-based) liquid level gauges, resistive gauges, ultrasound and transmission line-based level detectors. The present paper reviews these techniques and their suitability for He II service. In addition to these methods, techniques for measuring the total liquid volume and mass gauging are also discussed.

  3. Helium transfer line installation details.

    CERN Multimedia

    G. Perinic

    2007-01-01

    A particularity of the 32 m long four in one helium transfer line in between the cold box in USC55 and the cavern UX5 is the fact that the transfer line passes through a hole in the crane rail support beam. In order to ensure the alignment of the suspension rail in the interconnecting tunnel with the hole in the rail support as well as the connection points at both ends required precise measurements of the given geometries as well as the installation of a temporary target for the verification of the theoretical predictions.

  4. A 1 kW-class multi-stage heat-driven thermoacoustic cryocooler system operating at liquefied natural gas temperature range

    Science.gov (United States)

    Zhang, L. M.; Hu, J. Y.; Wu, Z. H.; Luo, E. C.; Xu, J. Y.; Bi, T. J.

    2015-07-01

    This article introduces a multi-stage heat-driven thermoacoustic cryocooler capable of reaching cooling capacity about 1 kW at liquefied natural gas temperature range without any moving mechanical parts. The cooling system consists of an acoustically resonant double-acing traveling wave thermoacoustic heat engine and three identical pulse tube coolers. Unlike other traditional traveling wave thermoacoustic heat engines, the acoustically resonant double-acting thermoacoustic heat engine is a closed-loop configuration consists of three identical thermoacoustic conversion units. Each pulse tube cooler is bypass driven by one thermoacoustic heat engine unit. The device is acoustically completely symmetric and therefore "self-matching" for efficient traveling-wave thermoacoustic conversion. In the experiments, with 7 MPa helium gas as working gas, when the heating temperature reaches 918 K, total cooling capacity of 0.88 kW at 110 K is obtained with a resonant frequency of about 55 Hz. When the heating temperature is 903 K, a maximum total cooling capacity at 130 K of 1.20 kW is achieved, with a thermal-to-cold exergy efficiency of 8%. Compared to previously developed heat-driven thermoacoustic cryocoolers, this device has higher thermal efficiency and higher power density. It shows a good prospect of application in the field of natural gas liquefaction and recondensation.

  5. Nanofabrication with a helium ion microscope

    NARCIS (Netherlands)

    Maas, D.; Van veldhoven, E.; Chen, P.; Sidorkin, V.; Salemink, H.; Van der Drift, E.; Alkemade, P.

    2010-01-01

    The recently introduced helium ion microscope (HIM) is capable of imaging and fabrication of nanostructures thanks to its sub-nanometer sized ion probe [1,2]. The unique interaction of the helium ions with the sample material provides very localized secondary electron emission, thus providing a valu

  6. Nanofabrication with a helium ion microscope

    NARCIS (Netherlands)

    Maas, D.; Van Veldhoven, E.; Chen, P.; Sidorkin, V; Salemink, H.; Van der Drift, E.; Alkemade, P.

    2009-01-01

    The recently introduced helium ion microscope (HIM) is capable of imaging and fabrication of nanostructures thanks to its sub-nanometer sized ion probe [1,2]. The unique interaction of the helium ions with the sample material provides very localized secondary electron emission, thus providing a valu

  7. Paramagnetic Attraction of Impurity-Helium Solids

    Science.gov (United States)

    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.

  8. LOX Tank Helium Removal for Propellant Scavenging

    Science.gov (United States)

    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).

  9. Elusive structure of helium trimers

    Science.gov (United States)

    Stipanović, Petar; Vranješ Markić, Leandra; Boronat, Jordi

    2016-09-01

    Over the years many He-He interaction potentials have been developed, some very sophisticated, including various corrections beyond the Born-Oppenheimer approximation. Most of them were used to predict properties of helium dimers and trimers, examples of exotic quantum states, whose experimental study proved to be very challenging. Recently, detailed structural properties of helium trimers were measured for the first time, allowing a comparison with theoretical predictions and possibly enabling the evaluation of different interaction potentials. The comparisons already made included adjusting the maxima of both theoretical and experimental correlation functions to one, so the overall agreement between theory and experiment appeared satisfactory. However, no attempt was made to evaluate the quality of the interaction potentials used in the calculations. In this work, we calculate the experimentally measured correlation functions using both new and old potentials, compare them with experimental data and rank the potentials. We use diffusion Monte Carlo simulations at T = 0, which give within statistical noise exact results of the ground state properties. All models predict both trimers 4He3 and 4He{}2{}3He to be in a quantum halo state.

  10. Helium abundances and the helium isotope anomaly of sdB stars

    CERN Document Server

    Geier, S; Edelmann, H; Morales-Rueda, L; Kilkenny, D; O'Donoghue, D; Marsh, T R; Copperwheat, C

    2011-01-01

    Helium abundances and atmospheric parameters have been determined from high resolution spectra for a new sample of 46 bright hot subdwarf B (sdB) stars. The helium abundances have been measured with high accuracy. We confirm the correlation of helium abundance with temperature and the existence of two distinct sequences in helium abundance found previously. We focused on isotopic shifts of helium lines and found helium-3 to be strongly enriched in 8 of our programme stars. Most of these stars cluster in a small temperature range between 27000 K and 31000 K very similar to the known helium-3-rich main sequence B stars, which cluster at somewhat lower temperatures. This phenomenon is most probably related to diffusion processes in the atmosphere, but poses a challenge to diffusion models.

  11. Effect of wall thickness and helium cooling channels on duct magnetohydrodynamic flows

    Energy Technology Data Exchange (ETDEWEB)

    He, Qingyun; Feng, Jingchao; Chen, Hongli, E-mail: hlchen1@ustc.edu.cn

    2016-02-15

    Highlights: • MHD flows in ducts of different wall thickness compared with wall uniform. • Study of velocity, pressure distribution in ducts MHD flows with single pass of helium cooling channels. • Comparison of three types of dual helium cooling channels and acquisition of an option for minimum pressure drop. • A single short duct MHD flow in blanket without FCI has been simulated for pressure gradient analysis. - Abstract: The concept of dual coolant liquid metal (LM) blanket has been proposed in different countries to demonstrate the technical feasibility of DEMO reactor. In the system, helium gas and PbLi eutectic, separated by structure grid, are used to cool main structure materials and to be self-cooled, respectively. The non-uniform wall thickness of structure materials gives rise to wall non-homogeneous conductance ratio. It will lead to electric current distribution changes, resulting in significant changes in the velocity distribution and pressure drop of magnetohydrodynamic (MHD) flows. In order to investigate the effect of helium channels on MHD flows, different methods of numerical simulations cases are carried out including the cases of different wall thicknesses, single pass of helium cooling channels, and three types of dual helium cooling channels. The results showed that helium tubes are able to affect the velocity distribution in the boundary layer by forming wave sharp which transfers from Hartmann boundary layer to the core area. In addition, the potential profile and pressure drop in the cases have been compared to these in the case of walls without cooling channel, and the pressure gradient of a simplified single short duct MHD flow in blanket shows small waver along the central axis in the helium channel position.

  12. Formation of the helium EUV resonance lines

    CERN Document Server

    Golding, Thomas Peter; Carlsson, Mats

    2016-01-01

    Context: While classical models successfully reproduce intensities of many transition region lines, they predict helium EUV line intensities roughly an order of magnitude lower than the observed value. Aims: To determine the relevant formation mechanism(s) of the helium EUV resonance lines, capable of explaining the high intensities under quiet sun conditions. Methods: We synthesise and study the emergent spectra from a 3D radiation-magnetohydrodynamics simulation model. The effects of coronal illumination and non-equilibrium ionisation of hydrogen and helium are included self-consistently in the numerical simulation. Results: Radiative transfer calculations result in helium EUV line intensities that are an order of magnitude larger than the intensities calculated under the classical assumptions. The enhanced intensity of He I 584 is primarily caused by He II recombination cascades. The enhanced intensity of He II 304 and He II 256 is caused primarily by non-equilibrium helium ionisation. Conclusion: The anal...

  13. Gemini helium closed cycle cooling system

    Science.gov (United States)

    Lazo, Manuel; Galvez, Ramon; Rogers, Rolando; Solis, Hernan; Tapia, Eduardo; Maltes, Diego; Collins, Paul; White, John; Cavedoni, Chas; Yamasaki, Chris; Sheehan, Michael P.; Walls, Brian

    2008-07-01

    The Gemini Observatory presents the Helium Closed Cycle Cooling System that provides cooling capacity at cryogenic temperatures for instruments and detectors. It is implemented by running three independent helium closed cycle cooling circuits with several banks of compressors in parallel to continuously supply high purity helium gas to cryocoolers located about 100-120 meters apart. This poster describes how the system has been implemented, the required helium pressures and gas flow to reach cryogenic temperature, the performance it has achieved, the helium compressors and cryocoolers in use and the level of vibration the cryocoolers produce in the telescope environment. The poster also describes the new technology for cryocoolers that Gemini is considering in the development of new instruments.

  14. Permeability of Hollow Microspherical Membranes to Helium

    Science.gov (United States)

    Zinoviev, V. N.; Kazanin, I. V.; Pak, A. Yu.; Vereshchagin, A. S.; Lebiga, V. A.; Fomin, V. M.

    2016-01-01

    This work is devoted to the study of the sorption characteristics of various hollow microspherical membranes to reveal particles most suitable for application in the membrane-sorption technologies of helium extraction from a natural gas. The permeability of the investigated sorbents to helium and their impermeability to air and methane are shown experimentally. The sorption-desorption dependences of the studied sorbents have been obtained, from which the parameters of their specific permeability to helium are calculated. It has been established that the physicochemical modification of the original particles exerts a great influence on the coefficient of the permeability of a sorbent to helium. Specially treated cenospheres have displayed high efficiency as membranes for selective extraction of helium.

  15. Global helium particle balance in LHD

    Energy Technology Data Exchange (ETDEWEB)

    Motojima, G., E-mail: motojima.gen@lhd.nifs.ac.jp [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Masuzaki, S.; Tokitani, M.; Kasahara, H.; Yoshimura, Y.; Kobayashi, M.; Sakamoto, R.; Morisaki, T.; Miyazawa, J.; Akiyama, T. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Ohno, N. [Graduate School of Engineering, Nagoya University, Nagoya, Aichi 464-8603 (Japan); Mutoh, T.; Yamada, H. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

    2015-08-15

    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 × 10{sup 22} 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.

  16. Exotic helium molecules; Molecules exotiques d'helium

    Energy Technology Data Exchange (ETDEWEB)

    Portier, M

    2007-12-15

    We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}P{sub 0}) molecule, or a {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 {+-} 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime {tau} = (1.4 {+-} 0.3) {mu}s is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

  17. Electric response in superfluid helium

    Science.gov (United States)

    Chagovets, Tymofiy V.

    2016-05-01

    We report an experimental investigation of the electric response of superfluid helium that arises in the presence of a second sound standing wave. It was found that the signal of the electric response is observed in a narrow range of second sound excitation power. The linear dependence of the signal amplitude has been derived at low excitation power, however, above some critical power, the amplitude of the signal is considerably decreased. It was established that the rapid change of the electric response is not associated with a turbulent regime generated by the second sound wave. A model of the appearance of the electric response as a result of the oscillation of electron bubbles in the normal fluid velocity field in the second sound wave is presented. Possible explanation for the decrease of the electric response are presented.

  18. In Beam Tests of Implanted Helium Targets

    CERN Document Server

    McDonald, J E; Ahmed, M W; Blackston, M A; Delbar, T; Gai, M; Kading, T J; Parpottas, Y; Perdue, B A; Prior, R M; Rubin, D A; Spraker, M C; Yeomans, J D; Weissman, L; Weller, H R; Delbar, Th.; Conn, LNS/U; Duke, TUNL/

    2006-01-01

    Targets consisting of 3,4He implanted into thin aluminum foils (approximately 100, 200 or 600 ug/cm^2) were prepared using intense (a few uA) helium beams at low energy (approximately 20, 40 or 100 keV). Uniformity of the implantation was achieved by a beam raster across a 12 mm diameter tantalum collimator at the rates of 0.1 Hz in the vertical direction and 1 Hz in the horizontal direction. Helium implantation into the very thin (approximately 80-100 ug/cm^2) aluminum foils failed to produce useful targets (with only approximately 10% of the helium retained) due to an under estimation of the range by the code SRIM. The range of low energy helium in aluminum predicted by Northcliffe and Shilling and the NIST online tabulation are observed on the other hand to over estimate the range of low energy helium ions in aluminum. An attempt to increase the amount of helium by implanting a second deeper layer was also carried out, but it did not significantly increase the helium content beyond the blistering limit (ap...

  19. FIELD STUDIES OF SINGLE POINT IMPACT ON LIQUEFIABLE SOIL FOUNDATION OF HIGHWAY

    Institute of Scientific and Technical Information of China (English)

    沈正; 刘志彬; 方磊; 李汉光

    2013-01-01

    A highway in the floodplain of the Abandoned Yellow River in the north of Jiangsu Province is recently remediated to reduce liquefaction potential using the dynamic compaction (DC) method of densification of in-place soils .Firstly ,the liquefaction potential of the soil at the project site is analysed according to the code of seismic de-sign .Then the in-situ single point impact tests are performed on the liquefiable soil .Settlement of crater ,excess pore pressure ,ground heave and lateral deformation under DC impact are measured and analyzed .Subsequently , the standard penetration test (SPT ) and cone penetration test (CPT ) are used for investigating the compaction ef-fectiveness .At last ,the improvement effect of DC is discussed according to the technical specification of dynamic consolidation to ground treatment .The investigation results indicate that the DC technique is an effective way for remediating liquefiable soil in highway engineering practice .

  20. Liquefied Gaseous Fuels Safety and Environmental Control Assessment Program: second status report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-10-01

    Volume 2 consists of 19 reports describing technical effort performed by Government Contractors in the area of LNG Safety and Environmental Control. Report topics are: simulation of LNG vapor spread and dispersion by finite element methods; modeling of negatively buoyant vapor cloud dispersion; effect of humidity on the energy budget of a liquefied natural gas (LNG) vapor cloud; LNG fire and explosion phenomena research evaluation; modeling of laminar flames in mixtures of vaporized liquefied natural gas (LNG) and air; chemical kinetics in LNG detonations; effects of cellular structure on the behavior of gaseous detonation waves under transient conditions; computer simulation of combustion and fluid dynamics in two and three dimensions; LNG release prevention and control; the feasibility of methods and systems for reducing LNG tanker fire hazards; safety assessment of gelled LNG; and a four band differential radiometer for monitoring LNG vapors.

  1. An experimental study on dynamic response for MICP strengthening liquefiable sands

    Science.gov (United States)

    Han, Zhiguang; Cheng, Xiaohui; Ma, Qiang

    2016-12-01

    The technology of bio-grouting is a new technique for soft ground improvement. Many researchers have carried out a large number of experiments and study on this topic. However, few studies have been carried out on the dynamic response of solidified sand samples, such reducing liquefaction in sand. To study this characteristic of microbial-strengthened liquefiable sandy foundation, a microorganism formula and grouting scheme is applied. After grouting, the solidified samples are tested via dynamic triaxial testing to examine the cyclic performance of solidified sand samples. The results indicate that the solidified sand samples with various strengths can be obtained to meet different engineering requirements, the use of bacteria solution and nutritive salt is reduced, and solidified time is shortened to 1-2 days. Most importantly, in the study of the dynamic response, it is found that the MICP grouting scheme is effective in improving liquefiable sand characteristic, such as liquefaction resistance.

  2. Evolution of dopant-induced helium nanoplasmas

    CERN Document Server

    Krishnan, S R; Fechner, L; Sharma, V; Kremer, M; Fischer, B; Camus, N; Pfeifer, T; Jha, J; Krishnamurthy, M; Schroeter, C -D; Ullrich, J; Stienkemeier, F; Moshammer, R; Fennel, Th; Mudrich, M

    2012-01-01

    Two-component nanoplasmas generated by strong-field ionization of doped helium nanodroplets are studied in a pump-probe experiment using few-cycle laser pulses in combination with molecular dynamics simulations. High yields of helium ions and a pronounced, droplet size-dependent resonance structure in the pump-probe transients reveal the evolution of the dopant-induced helium nanoplasma. The pump-probe dynamics is interpreted in terms of strong inner ionization by the pump pulse and resonant heating by the probe pulse which controls the final charge states detected via the frustration of electron-ion recombination.

  3. Particle detection by evaporation from superfluid helium

    Energy Technology Data Exchange (ETDEWEB)

    Bandler, S.R.; Lanou, R.E.; Maris, H.J.; More, T.; Porter, F.S.; Seidel, G.M.; Torii, R.H. (Department of Physics, Brown University, Providence, Rhode Island 02912 (United States))

    1992-04-20

    We report the first experiments in which 5-MeV alpha particles are detected via evaporation from a bath of superfluid helium. The {alpha} excites phonons and rotons in the liquid helium, and these excitations are sufficiently energetic to evaporate helium atoms when they reach the free surface of the liquid. The approximate overall efficiency of this process has been determined, and we compare this with expectations. We have also been able to detect evaporation induced by a flux of {gamma}'s from a {sup 137}Cs source.

  4. Feasibility Analysis of Liquefying Oxygen Generated from Water Electrolysis Units on Lunar Surface

    Science.gov (United States)

    Jeng, Frank F.

    2009-01-01

    Concepts for liquefying oxygen (O2) generated from water electrolysis subsystems on the Lunar surface were explored. Concepts for O2 liquefaction units capable of generating 1.38 lb/hr (0.63 kg/hr) liquid oxygen (LOX) were developed. Heat and mass balance calculations for the liquefaction concepts were conducted. Stream properties, duties of radiators, heat exchangers and compressors for the selected concepts were calculated and compared.

  5. Liquefied natural gas as a transportation fuel for heavy-duty trucks: Volume I

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    This document contains Volume 1 of a three-volume manual designed for use with a 2- to 3-day liquefied natural gas (LNG) training course. Transportation and off-road agricultural, mining, construction, and industrial applications are discussed. This volume provides a brief introduction to the physics and chemistry of LNG; an overview of several ongoing LNG projects, economic considerations, LNG fuel station technology, LNG vehicles, and a summary of federal government programs that encourage conversion to LNG.

  6. Plant Design of Cluster LNG (Liquefied Natural Gas in Bukit Tua Well, Gresik

    Directory of Open Access Journals (Sweden)

    Pradnya A. Putri

    2013-03-01

    Full Text Available Gas alam atau yang sering disebut sebagai gas bumiadalah bahan bakar fosil berbentuk gas yang terutama terdiridari metana (CH. Gas alam cair (Liquefied Natural Gas adalahgas alam yang telah diproses untuk menghilangkan pengotor danhidrokarbon berat kemudian gas alam dikondensasi menjadicairan pada tekanan atmosfer dengan mendinginkannya sekitar 160oPlant Design of Cluster LNG (Liquefied Natural Gas inBukit Tua Well, Gresik Pradnya A. Putri, Shinta S. Hajar, Gede Wibawa dan WinarsihJurusan Teknik Kimia, Fakultas Teknologi Industri, Institut Teknologi Sepuluh Nopember (ITS 4C dengan tujuan untuk mempermudah pengangkutan karenavolume gas sebelum dan sesudah dicairkan adalah 600:1. Saat inigas alam diolah menjadi Liquefied Natural Gas (LNG danLiquefied Petroleum Gas (LPG, sedangkan sisa pencairan gasalam yang berupa condensate juga memiliki nilai ekonomis yangtinggi karena sifatnya yang mirip minyak mentah (crude oildengan kualitas yang terbaik. Gas alam tidak berwarna, tidakberbau, tidak korosif, tidak beracun, dan ramah lingkungan. Gasalam juga digunakan sebagai pembangkit listrik PLTG danPLTU. Berdasarkan data Neraca Gas Indonesia pada tahun 2010Indonesia mengalami defisit sebesar 18,57 MTPA (Million TonPer Annum. Pabrik Cluster LNG direncanakan dibangun padatahun 2015 dengan target siap beroperasi pada tahun 2018.Pabrik ini berlokasi di Gresik dengan bahan baku yang diperolehdari sumur Lapangan Bukit Tua, Gresik, Jawa Timur dengancadangan gas alam sebesar 52359,62 MMSCFD. Kapasitaspabrik ini adalah 20 MMSCFD. Pabrik ini akan memenuhikebutuhan konsumen skala kecil hingga menengah atas sepertihalnya pembangkit listrik untuk daerah Bali, Lombok dan JawaTimur. Rangkaian proses pabrik ini adalah unit Dehydration, unitAcid Gas Removal, unit Refrigeration dan unit Liquefaction.Analisa ekonomi dari pabrik ini adalah investasi sebesar 60MUSD, IRR sebesar 39,67%, POT selama 2,38 tahun, BEPsebesar 18% dan NPV 10 tahun sebesar 63,904 MUSD.

  7. Impact of Coaching and Mentoring in the Nigeria Liquefied Natural Gas Company Limited, Bonny

    Directory of Open Access Journals (Sweden)

    Agwu Mba Okechukwu

    2015-02-01

    Full Text Available The paper examined the impact of coaching and mentoring in the Nigeria liquefied natural gas company limited, bonny. The research question addressed the extent at which improved employees job performance/reduced employees turnover  is influenced by the implementation of coaching and mentoring program in the Nigeria liquefied natural gas company limited, bonny. It views coaching and mentoring as learning relationships that improve employees’ job skills and develop their potentials for better performance. The core aspect of the study is the use of cross-sectional survey research design in generating the required primary data. The place of study is the bonny industrial area of the Nigeria liquefied natural gas company while the duration of study is between December 2013 and November 2014. A sample of 370(184 Direct staff, 150 Contract staff and 36 Seconded staff respondents determined at 5% level of significance for sample error, using Yamane’s formula, was selected from a population of 4,895 employees using stratified random sampling method for the purpose of questionnaire administration. The results indicated that implementation of coaching and mentoring  program in the Nigeria liquefied natural gas company limited bonny, to a large extent influenced improved employees’ performance(74.32% response rate and reduced employees turnover(67.57% response rate.It therefore recommends among others: sustenance of the current coaching and mentoring program, regular appraisal of employees job skill requirements, continuous staff development, regular improvement of employees’ condition of service and sustenance of current team building efforts/ incentive scheme. Keywords: Coaching and mentoring, employees’ performance, employees’ turnover,organizational performance, NLNG bonny. 

  8. Calculated Regenerator Performance at 4 K with HELIUM-4 and HELIUM-3

    Science.gov (United States)

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

    2008-03-01

    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 transport 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.

  9. Charging dynamics of dopants in helium nanoplasmas

    OpenAIRE

    Heidenreich, Andreas; Grüner, Barbara; Schomas, Dominik; Stienkemeier, Frank; Krishnan, Siva Rama; Mudrich, Marcel

    2016-01-01

    We present a combined experimental and theoretical study of the charging dynamics of helium nanodroplets doped with atoms of different species and irradiated by intense near-infrared (NIR) laser pulses (

  10. Charged Condensate and Helium Dwarf Stars

    CERN Document Server

    Gabadadze, Gregory

    2008-01-01

    White dwarf stars composed of carbon, oxygen or heavier elements are expected to crystallize as they cool down below certain temperatures. Yet, simple arguments suggest that the helium white dwarf cores may not solidify, mostly because of zero-point oscillations of the helium ions that would dissolve the crystalline structure. We argue that the interior of the helium dwarfs may instead form a macroscopic quantum state in which the charged helium-4 nuclei are in a Bose-Einstein condensate, while the relativistic electrons form a neutralizing degenerate Fermi liquid. We discuss the electric charge screening, and the spectrum of this substance, showing that the bosonic long-wavelength fluctuations exhibit a mass gap. Hence, there is a suppression at low temperatures of the boson contribution to the specific heat -- the latter being dominated by the specific heat of the electrons near the Fermi surface. This state of matter may have observational signatures.

  11. Primary helium heater for propellant pressurization systems

    Science.gov (United States)

    Reichmuth, D. M.; Nguyen, T. V.; Pieper, J. L.

    1991-01-01

    The primary helium heater is a unique design that provides direct heating of pressurant gas for large pressure fed propulsion systems. It has been conceptually designed to supply a heated (800-1000 R) pressurization gas to both a liquid oxygen and an RP-1 propellant tank. This pressurization gas is generated within the heater by mixing super critical helium (40-300 R and 3000-1600 psi) with an appropriate amount of combustion products from a 4:1 throttling stoichiometric LO2/LH2 combustor. This simple, low cost and reliable mixer utilizes the large quantity of helium to provide stoichiometric combustor cooling, extend the throttling limits and enhance the combustion stability margin. Preliminary combustion, thermal, and CFD analyses confirm that this low-pressure-drop direct helium heater can provide the constant-temperature pressurant suitable for tank pressurization of both fuel and oxidizer tanks of large pressure fed vehicles.

  12. ASACUSA Anti-protonic Helium_Final

    CERN Document Server

    CERN Audiovisual Production Service; CERN AD; Paola Catapano; Julien Ordan, Arzur Catel; Paola Catapano; ASACUSA COLLABORATION

    2016-01-01

    Latest precision measurement of the mass of the proton and the anti proton though the production of antiprotonic helium by the ASACUSA experiment at CERN's antimatter factory, with a beam from the Antiproton Decelerator

  13. Effects of helium impurities on superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Selle, J.E.

    1977-07-01

    A review of the literature on the effects of helium impurities on superalloys at elevated temperatures was undertaken. The actual effects of these impurities vary depending on the alloy, composition of the gas atmosphere, and temperature. In general, exposure in helium produces significant but not catastrophic changes in the structure and properties of the alloys. The effects of these treatments on the structure, creep, fatigue, and mechanical properties of the various alloys are reviewed and discussed. Suggestions for future work are presented.

  14. Cosmogenic helium in a terrestrial igneous rock

    Science.gov (United States)

    Kurz, M. D.

    1986-01-01

    New helium isotopic measurements on samples from the Kula formation of Haleakala volcano of Hawaii are presented that are best explained by an in situ cosmogenic origin for a significant fraction of the He-3. Results from crushing and stepwise heating experiments, and consideration of the exposure age of the sample at the surface and the cosmic ray fluxes strongly support this hypothesis. Although crustal cosmogenic helium has been proposed previously, this represents its first unambiguous identification in a terrestrial sample.

  15. Helium behaviour in implanted boron carbide

    Directory of Open Access Journals (Sweden)

    Motte Vianney

    2015-01-01

    Full Text Available When boron carbide is used as a neutron absorber in nuclear power plants, large quantities of helium are produced. To simulate the gas behaviour, helium implantations were carried out in boron carbide. The samples were then annealed up to 1500 °C in order to observe the influence of temperature and duration of annealing. The determination of the helium diffusion coefficient was carried out using the 3He(d,p4He nuclear reaction (NRA method. From the evolution of the width of implanted 3He helium profiles (fluence 1 × 1015/cm2, 3 MeV corresponding to a maximum helium concentration of about 1020/cm3 as a function of annealing temperatures, an Arrhenius diagram was plotted and an apparent diffusion coefficient was deduced (Ea = 0.52 ± 0.11 eV/atom. The dynamic of helium clusters was observed by transmission electron microscopy (TEM of samples implanted with 1.5 × 1016/cm2, 2.8 to 3 MeV 4He ions, leading to an implanted slab about 1 μm wide with a maximum helium concentration of about 1021/cm3. After annealing at 900 °C and 1100 °C, small (5–20 nm flat oriented bubbles appeared in the grain, then at the grain boundaries. At 1500 °C, due to long-range diffusion, intra-granular bubbles were no longer observed; helium segregates at the grain boundaries, either as bubbles or inducing grain boundaries opening.

  16. Multiple Population Theory: Extreme helium population problem

    OpenAIRE

    Yi, Sukyoung K.

    2009-01-01

    The spreads in chemical abundances inferred by recent precision observations suggest that some or possibly all globular clusters can no longer be considered as simple stellar populations. The most striking case is omega Cen in the sense that its bluest main-sequence despite its high metallicity demands an extreme helium abundance of Y > 0.4. I focus on this issue of "the extreme helium population problem" in this review.

  17. Helium Reionization in From New Sightlines

    Science.gov (United States)

    Syphers, David

    2017-01-01

    A very small number of sightlines to z~3 quasars have been studied in detail to show the progress of helium reionization. Although studying the same sightlines with each new UV spectrograph lead to a better understanding of them, the sightline variance is very strong during this patchy and extended process. We discuss detailed R>10,000 COS data from new sightlines, and what they reveal about the progress and end of helium reionization.

  18. Helium and Neon in Comets

    Science.gov (United States)

    Jewitt, David

    1996-01-01

    Two comets were observed with EUVE in late 1994. Both comet Mueller and comet Borrelly are short-period comets having well established orbital elements and accurate ephemerides. Spectra of 40 ksec were taken of each. No evidence for emission lines from either Helium or Neon was detected. We calculated limits on the production rates of these atoms (relative to solar) assuming a standard isotropic outflow model, with a gas streaming speed of 1 km/s. The 3-sigma (99.7% confidence) limits (1/100,000 for He, 0.8 for Ne) are based on a conservative estimate of the noise in the EUVE spectra. They are also weakly dependent on the precise pointing and tracking of the EUVE field of view relative to the comet during the integrations. These limits are consistent with ice formation temperatures T greater than or equal to 30 K, as judged from the gas trapping experiments of Bar-Nun. For comparison, the solar abundances of these elements are He/O = 110, Ne/O = 1/16. Neither limit was as constraining as we had initially hoped, mainly because comets Mueller and Borrelly were intrinsically less active than anticipated.

  19. Photoionization rates for helium: update

    CERN Document Server

    Sokół, Justyna M

    2014-01-01

    The NIS He gas has been observed at a few AU to the Sun almost from the beginning of the space age. To model its flow an estimate of the loss rates due to ionization by solar extreme-ultraviolet (EUV) flux is needed. The EUV irradiance has been measured directly from mid 1990-ties, but with high temporal and spectral resolution only from 2002. Beforehand only EUV proxies are available. A new method of reconstruction of the Carrington rotation averaged photoionization rates for neutral interstellar helium (NIS He) in the ecliptic at 1 AU to the Sun before 2002 is presented. We investigate the relation between the solar rotation averaged time series of the ionization rates for NIS He at 1 AU derived from TIMED measurements of EUV irradiance and the solar 10.7 cm flux (F10.7) only. We perform a weighted iterative fit of a nonlinear model to data split into sectors. The obtained formula allows to reconstruct the solar rotation averages of photoionization rates for He between ~1947 and 2002 with an uncertainty ran...

  20. Pyridine Aggregation in Helium Nanodroplets

    Science.gov (United States)

    Nieto, Pablo; Poerschke, Torsten; Habig, Daniel; Schwaab, Gerhard; Havenith, Martina

    2012-06-01

    Pyridine crystals show the unusual property of isotopic polymorphism. Experimentally it has been observed that deuterated pyridine crystals exist in two phases while non-deuterated pyridine does not show a phase transition. Therefore, although isotopic substitution is the smallest possible modification of a molecule it greatly affects the stability of pyridine crystals. A possible experimental approach in order to understand this striking effect might be the study of pyridine aggregation for small clusters. By embedding the clusters in helium nanodroplets the aggregates can be stabilized and studied by means of Infrared Depletion Spectroscopy. Pyridine oligomers were investigated in the C-H asymmetric vibration region (2980-3100 cm-1) using this experimental technique. The number of molecules for the clusters responsibles for each band were determined by means of pick-up curves as well as mass sensitive depletion spectra. Furthermore, the intensity dependence of the different bands on applying a dc electric field was studied. The assignment of the different structures for pyridine clusters on the basis of these measurements were also carried out. S. Crawford et al., Angew. Chem. Int. Ed., 48, 755 (2009).

  1. Effect of dislocations on helium retention in deformed pure iron

    Science.gov (United States)

    Gong, Y. H.; Cao, X. Z.; Jin, S. X.; Lu, E. Y.; Hu, Y. C.; Zhu, T.; Kuang, P.; Xu, Q.; Wang, B. Y.

    2016-12-01

    The effects of dislocations created by deformation on helium retention in pure iron, including the helium atoms diffusion along the dislocation line and desorption from dislocation trapping sites, were investigated. The dislocation defect was introduced in specimens by cold-rolling, and then 5 keV helium ions were implanted into the deformed specimens. Slow positron beam technology and thermal desorption spectroscopy were used to investigate the evolution of dislocation defects and the desorption behavior of helium atoms under influence of dislocation. The behaviors of S-E, W-E and S-W plots indicate clearly that lots of helium atoms remain in the deformed specimen and helium atoms combining with dislocation change the distribution of electron density. The helium desorption plot indicates that dislocation accelerates helium desorption at 293 K-600 K and facilitates helium dissociation from HenVm (n/m = 1.8) cluster.

  2. High resolution helium ion scanning microscopy of the rat kidney.

    Directory of Open Access Journals (Sweden)

    William L Rice

    Full Text Available Helium ion scanning microscopy is a novel imaging technology with the potential to provide sub-nanometer resolution images of uncoated biological tissues. So far, however, it has been used mainly in materials science applications. Here, we took advantage of helium ion microscopy to explore the epithelium of the rat kidney with unsurpassed image quality and detail. In addition, we evaluated different tissue preparation methods for their ability to preserve tissue architecture. We found that high contrast, high resolution imaging of the renal tubule surface is possible with a relatively simple processing procedure that consists of transcardial perfusion with aldehyde fixatives, vibratome tissue sectioning, tissue dehydration with graded methanol solutions and careful critical point drying. Coupled with the helium ion system, fine details such as membrane texture and membranous nanoprojections on the glomerular podocytes were visualized, and pores within the filtration slit diaphragm could be seen in much greater detail than in previous scanning EM studies. In the collecting duct, the extensive and striking apical microplicae of the intercalated cells were imaged without the shrunken or distorted appearance that is typical with conventional sample processing and scanning electron microscopy. Membrane depressions visible on principal cells suggest possible endo- or exocytotic events, and central cilia on these cells were imaged with remarkable preservation and clarity. We also demonstrate the use of colloidal gold probes for highlighting specific cell-surface proteins and find that 15 nm gold labels are practical and easily distinguishable, indicating that external labels of various sizes can be used to detect multiple targets in the same tissue. We conclude that this technology represents a technical breakthrough in imaging the topographical ultrastructure of animal tissues. Its use in future studies should allow the study of fine cellular details

  3. Full Scale Thermo-hydraulic Simulation of a Helium-Helium Printed Circuit Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Injun; Hong, Sungyull; Bai, Cheolho; Shim, Jaesool [Yeungnam Univ., Gyeongsan (Korea, Republic of); Kim, Chansoo; Hong, Sungdeok; Kim, Minhwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    In this paper, the thermo-hydraulic full scale simulation is performed to study the temperature distributions, thermal stress, pressure drop and outlet temperature in a Helium-Helium printed circuit heat exchanger (PCHE) in a VHTR simulate helium loop. The entire PCHE is composed of 40 stacks of rectangular shaped micro-channels for helium gas [type A] (inlet temperature, 400 .deg. C) and 40 stacks of semi-ellipse shaped micro-channels for helium [type B] (inlet temperature, 300 .deg. C). The experimental result is compared to that of computer simulation, COMSOL multi-physics software. The Helium-Helium PCHE is considered a prototype of the newly developed PCHE by Korea Atomic Energy Research Institute (KAERI). The full scale thermo-hydraulic simulation was successfully performed to obtain temperature distribution, pressure drop and thermal stress in 40 sets of flow channel stacks in a helium-helium printed circuit heat exchanger in a VHTR simulate helium loop. We obtained a quite similar temperature distribution with the 3D measured infrared temperature distribution. To our knowledge, this is the first full scale numerical study on the PCHE, which considers all microchannels, that the convection effect on the outside surfaces of the PCHE is applied. The very high-temperature reactor (VHTR) or high-temperature gas-cooled reactor(HTGR) is a fourth-generation nuclear power reactor that uses the ceramic coated fuel, TRISO, in which the fission gas does not leak even at temperatures higher than 1600 .deg. C. The VHTR necessarily requires an intermediate loop composed of a hot gas duct (HGD), an intermediate heat exchanger (IHX) and a process heat exchanger (PHE). The IHX is one of the important components of VHTR system because the IHX transfers the 950 .deg. C of high temperature massive heat to a hydrogen production plant or power conversion unit at high system pressure.

  4. Experimental investigation of mobile small-scale liquefier for 10000 NM3/D of coal bed methane gas

    Science.gov (United States)

    Sun, Zhaohu; Wu, J. F.; Gong, Maoqiong; Guo, Ping

    2012-06-01

    There is a growing recognition that unconventional sources of gas, such as shale gas, coal bed methane (CBM) and deep tight gas will contribute a significant component of future gas supplies as technologies evolve. In recent years, the interest in such source of gas utilization technologies based on small-scale LNG production has been rising steeply. In this paper, a mobile liquefier prototype for 10000 Nm3/d of CBM has been designed, constructed and tested. It has two cascade refrigeration systems. The high-temperature refrigeration system will pre-cool the resource gas to 5oC, and the low-temperature refrigeration system will continue to cool the resource gas to the liquefied point with a Mixed Refrigerant Cycle (MRC). The kernel compressor is a conventional oil-lubricated air-conditioning compressor with the discharge pressure of 2.0 MPa. The main heat exchanger is plate-fin heat exchanger with four passages. A series of experiments have been done on the prototype liquefier at different resource gas pressures and environmental temperatures. It is less than one hour from the start of the equipment to the existence of LNG. The maximum production of LNG is about 20 m3/d when a stream of about 12500 Nm3/d of pure CBM at a process pressure of 1.3 MPa is liquefied. The energy consumption of liquefying 1 Nm3 methane is 0.612 kWh.

  5. Analysis of temperature and pressure changes in liquefied natural gas (LNG) cryogenic tanks

    Science.gov (United States)

    Chen, Q.-S.; Wegrzyn, J.; Prasad, V.

    2004-10-01

    Liquefied natural gas (LNG) is being developed as a transportation fuel for heavy vehicles such as trucks and transit buses, to lessen the dependency on oil and to reduce greenhouse gas emissions. The LNG stations are properly designed to prevent the venting of natural gas (NG) from LNG tanks, which can cause evaporative greenhouse gas emissions and result in fluctuations of fuel flow and changes of fuel composition. Boil-off is caused by the heat added into the LNG fuel during the storage and fueling. Heat can leak into the LNG fuel through the shell of tank during the storage and through hoses and dispensers during the fueling. Gas from tanks onboard vehicles, when returned to LNG tanks, can add additional heat into the LNG fuel. A thermodynamic and heat transfer model has been developed to analyze different mechanisms of heat leak into the LNG fuel. The evolving of properties and compositions of LNG fuel inside LNG tanks is simulated. The effect of a number of buses fueled each day on the possible total fuel loss rate has been analyzed. It is found that by increasing the number of buses, fueled each day, the total fuel loss rate can be reduced significantly. It is proposed that an electric generator be used to consume the boil-off gas or a liquefier be used to re-liquefy the boil-off gas to reduce the tank pressure and eliminate fuel losses. These approaches can prevent boil-off of natural gas emissions, and reduce the costs of LNG as transportation fuel.

  6. Natural Gas and Indoor Air Pollution: A Comparison With Coal Gas and Liquefied Petroleum Gas

    Institute of Scientific and Technical Information of China (English)

    YUE ZHANG; BAO-SHENG CHEN; GUANG-QUAN LIU; JU-NING WANG; ZHEN-HUA ZHAO; LIAN-QING LIN

    2003-01-01

    The study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution. Methods Regular pollutants including B(a)P were monitored and 1-hydroxy pyrene were tested in urine of the enrolled subjects.Radon concentrations and their changes in four seasons were also monitored in the city natural gas from its source plant and transfer stations to final users. To analyze organic components of coal gas,liquefied petroleum gas and natural gas, a high-flow sampling device specially designed was used to collect their combustion products, and semi-volatile organic compounds contained in the particles were detected by gas chromatograph-mass spectrograph (GC/MS). Results Findings in the study showed that the regular indoor air pollutants particles and CO were all above the standard in winter when heating facilities were operated in the city, but they were lowest in kitchens using natural gas;furthermore, although NO2 and CO2 were slightly higher in natural gas, B(a)P concentration was lower in this group and 1-hydroxy pyrene was lowest in urine of the subjects exposed to natural gas.Organic compounds were more complicated in coal gas and liquefied petroleum gas than in natural gas. The concentration of radon in natural gas accounted for less than 1‰ of its effective dose contributing to indoor air pollution in Beijing households. Conclusion Compared to traditional fuels, gases are deemed as clean ones, and natural gas is shown to be cleaner than the other two gases.

  7. Helium release from radioisotope heat sources

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, D.E.; Early, J.W.; Starzynski, J.S.; Land, C.C.

    1984-05-01

    Diffusion of helium in /sup 238/PuO/sub 2/ fuel was characterized as a function of the heating rate and the fuel microstructure. The samples were thermally ramped in an induction furnace and the helium release rates measured with an automated mass spectrometer. The diffusion constants and activation energies were obtained from the data using a simple diffusion model. The release rates of helium were correlated with the fuel microstructure by metallographic examination of fuel samples. The release mechanism consists of four regimes, which are dependent upon the temperature. Initially, the release is controlled by movement of point defects combined with trapping along grain boundaries. This regime is followed by a process dominated by formation and growth of helium bubbles along grain boundaries. The third regime involves volume diffusion controlled by movement of oxygen vacancies. Finally, the release at the highest temperatures follows the diffusion rate of intragranular bubbles. The tendency for helium to be trapped within the grain boundaries diminishes with small grain sizes, slow thermal pulses, and older fuel.

  8. Hydrodynamic simulations of the core helium flash

    CERN Document Server

    Mocak, M; Weiss, A; Kifonidis, K; 10.1017/S1743921308022813

    2009-01-01

    We describe and discuss hydrodynamic simulations of the core helium flash using an initial model of a 1.25 M_sol star with a metallicity of 0.02 near at its peak. Past research concerned with the dynamics of the core helium flash is inconclusive. Its results range from a confirmation of the standard picture, where the star remains in hydrostatic equilibrium during the flash (Deupree 1996), to a disruption or a significant mass loss of the star (Edwards 1969; Cole & Deupree 1980). However, the most recent multidimensional hydrodynamic study (Dearborn 2006) suggests a quiescent behavior of the core helium flash and seems to rule out an explosive scenario. Here we present partial results of a new comprehensive study of the core helium flash, which seem to confirm this qualitative behavior and give a better insight into operation of the convection zone powered by helium burning during the flash. The hydrodynamic evolution is followed on a computational grid in spherical coordinates using our new version of th...

  9. Thermal Performance of the XRS Helium Insert

    Science.gov (United States)

    Breon, Susan R.; DiPirro, Michael J.; Tuttle, James G.; Shirron, Peter J.; Warner, Brent A.; Boyle, Robert F.; Canavan, Edgar R.

    1999-01-01

    The X-Ray Spectrometer (XRS) is an instrument on the Japanese Astro-E satellite, scheduled for launch early in the year 2000. The XRS Helium Insert comprises a superfluid helium cryostat, an Adiabatic Demagnetization Refrigerator (ADR), and the XRS calorimeters with their cold electronics. The calorimeters are capable of detecting X-rays over the energy range 0.1 to 10 keV with a resolution of 12 eV. The Helium Insert completed its performance and verification testing at Goddard in January 1999. It was shipped to Japan, where it has been integrated with the neon dewar built by Sumitomo Heavy Industries. The Helium Insert was given a challenging lifetime requirement of 2.0 years with a goal of 2.5 years. Based on the results of the thermal performance tests, the predicted on-orbit lifetime is 2.6 years with a margin of 30%. This is the result of both higher efficiency in the ADR cycle and the low temperature top-off, more than compensating for an increase in the parasitic heat load. This paper presents a summary of the key design features and the results of the thermal testing of the XRS Helium Insert.

  10. Large-Scale Wireless Temperature Monitoring System for Liquefied Petroleum Gas Storage Tanks

    Directory of Open Access Journals (Sweden)

    Guangwen Fan

    2015-09-01

    Full Text Available Temperature distribution is a critical indicator of the health condition for Liquefied Petroleum Gas (LPG storage tanks. In this paper, we present a large-scale wireless temperature monitoring system to evaluate the safety of LPG storage tanks. The system includes wireless sensors networks, high temperature fiber-optic sensors, and monitoring software. Finally, a case study on real-world LPG storage tanks proves the feasibility of the system. The unique features of wireless transmission, automatic data acquisition and management, local and remote access make the developed system a good alternative for temperature monitoring of LPG storage tanks in practical applications.

  11. Large >60 gallon/day ‘pulse-tube’ oxygen liquefier for aircraft carriers

    Science.gov (United States)

    Spoor, P. S.

    2015-12-01

    An oxygen liquefier using a large ‘pulse-tube’ or acoustic-Stirling cryocooler is described, which has a liquefaction rate in excess of 60 gallons per day (227 liters per day) as measured by the increase in weight of a storage dewar, from <20 kWe input. Several of these systems will be deployed on U.S. Navy aircraft carriers to provide shipboard liquid oxygen. Paths to improvement in future systems are identified, although it is noted that since the present system exceeds the required specifications, these improvements may not be implemented in the near term.

  12. Preparation and Characterization of Rare Earth Composite Materials Radiating Far Infrared for Activating Liquefied Petroleum Gas

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Rare earth composite materials radiating far-infrared rays were prepared according to far infrared absorption spectrum of main component in liquefied petroleum gas (LPG). The composite materials were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transformed infrared spectra(FTIR). The results show that after the composite materials were calcined at 873 K for 4 h, FTIR spectra of rare earth composite materials display two new peaks at 1336 and 2926 cm-1 available for activating LPG.

  13. Sinking/floatation of pipelines and other objects in liquefied soil under waves

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen; Christensen, S.;

    1999-01-01

    This paper presents the results of an experimental study where the sinking and floatation of a pipeline and other objects (namely, a sphere and a cube) in a silt bed was investigated. The bed was exposed to progressive waves. Two kinds of experiments were made: The undisturbed-flow experiments......, and the experiments with the structure model (a pipeline, a sphere, and a cube). In the former experiments, the pore-water pressure was measured across the soil depth. The pore-water pressure built up, as the waves progressed. The soil was liquefied for wave heights larger than a critical value. Regarding...

  14. On the application of computational fluid dynamics codes for liquefied natural gas dispersion.

    Science.gov (United States)

    Luketa-Hanlin, Anay; Koopman, Ronald P; Ermak, Donald L

    2007-02-20

    Computational fluid dynamics (CFD) codes are increasingly being used in the liquefied natural gas (LNG) industry to predict natural gas dispersion distances. This paper addresses several issues regarding the use of CFD for LNG dispersion such as specification of the domain, grid, boundary and initial conditions. A description of the k-epsilon model is presented, along with modifications required for atmospheric flows. Validation issues pertaining to the experimental data from the Burro, Coyote, and Falcon series of LNG dispersion experiments are also discussed. A description of the atmosphere is provided as well as discussion on the inclusion of the Coriolis force to model very large LNG spills.

  15. [Ecological/hygienic and toxicological evaluation of combustion products of aviation kerosene and liquefied natural gas].

    Science.gov (United States)

    Afanas'ev, R V; Berezin, G I; Raznoschikov, V V

    2006-01-01

    Products of kerosene combustion in the present-day aeroengines contain more than 200 compounds of incomplete combustion, partial oxidation, and thermal decomposition of fuel and oil. Most of these are strong toxicants for humans. Increase of temperature in the turbine engine combustion chamber led to production of very toxic nitrogen oxides. In search for the ecologically safe and less toxic alternative attention of fuel engineers was drawn to liquefied natural gas which compares well and even excels kerosene in ecological, economic and many other respects.

  16. Size Distribution of Particles Emitted from Liquefied Natural Gas Fueled Engine

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The results of measurements conducted to determine the number and mass concentration of particles emitted from the liquefied natural gas (LNG) fueled spark ignition engines are presented. Particle size distributions were measured at different speeds, different loads and ESC cycles. The nanoparticles with diameter smaller than 39nm, measured by the electrical low-pressure impactor (ELPI), are dominant in number concentration that is nearly 92.7% of the total number of the emitted particles at the peak point. As for the mass of emission particle, it is shown that the mass of the particles greater than 1.2μm is more than 65% that of the emitted particles.

  17. Analysis of the liquefied and solubilized coals by the action of microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Luna, N.; Fernandez, M.; Monistrol, I.F.; Laborda, F. [Madrid Univ. (Spain). Dept. de Microbiologia y Parasitologia

    1997-12-31

    The analysis of liquefied/solubilized products from lignite by microorganisms showed some alterations in the chemical composition with regard to the original coal. Noteworthy, a reduction in the average molecular weight and an increase in the condensation index of humic acids derived from the liquid lignite were observed. These results could indicate that microorganisms degrade the humic acids to rend them more suitable as microbial nutrients. The observation that microorganisms could use humic acids as the only carbon source supported this supposition. (orig.)

  18. Development of the Helium Cooled Lithium Lead blanket for DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Aiello, G., E-mail: giacomo.aiello@cea.fr [CEA-Saclay, DEN/DANS/DM2S/SEMT/BCCR, 91191 Gif Sur Yvette Cedex (France); Aubert, J.; Jonquères, N. [CEA-Saclay, DEN/DANS/DM2S/SEMT/BCCR, 91191 Gif Sur Yvette Cedex (France); Li Puma, A. [CEA-Saclay, DEN/DANS/DM2S/SERMA/LPEC, 91191 Gif Sur Yvette Cedex (France); Morin, A.; Rampal, G. [CEA-Saclay, DEN/DANS/DM2S/SEMT/BCCR, 91191 Gif Sur Yvette Cedex (France)

    2014-10-15

    Highlights: • The HCLL blanket design has been modified to adapt it to the 2012 EFDA DEMO specifications. • The new design has been developed with the aim to capitalize on TBM experience in ITER. • A new attachment system for the modules has been proposed. - Abstract: The Helium Cooled Lithium Lead (HCLL) blanket is one of the candidate European blanket concepts selected for the DEMOnstration fusion power plant that should follow ITER. In a fusion power plant, the blanket is one of the key components because of its impact on the plant performance, availability, safety and economics. In 2012, the European Fusion Development Agreement (EFDA) agency issued new specifications for DEMO: this paper describes the work performed to adapt the previous 2007 HCLL-DEMO blanket design to those specifications. A new segmentation has been defined assuming straight surfaces for all blanket modules. Following the Multi Module Segment (MMS) option, all modules are attached to a common back supporting structure which also serves as manifold for Helium and PbLi distribution. A detailed CAD design of the central outboard module has been defined. Thermo-hydraulic and thermo-mechanical analyses on of the First Wall and Breeder Zone have been carried out. For the attachment of the modules to the common backplate, a new solution based on the use of Tie Rods, derived from the design of the corresponding HCLL Test Blanket Module for ITER, has been proposed. This paper also identifies the priorities for further development of the HCLL blanket design.

  19. Helium corona-assisted air discharge

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Nan; Gao Lei; Ji Ailing; Cao Zexian [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-10-15

    Operation of atmospheric discharge of electronegative gases including air at low voltages yet without consuming any inert gas will enormously promote the application of non-thermal plasmas. By taking advantage of the low onset voltage for helium corona, air discharge was successfully launched at much reduced voltages with a needle-plate system partly contained in a helium-filled glass bulb--for a needle-plate distance of 12 mm, 1.0 kV suffices. Ultraviolet emission from helium corona facilitates the discharging of air, and the discharge current manifests distinct features such as relatively broad Trichel pulses in both half periods. This design allows safe and economic implementation of atmospheric discharge of electronegative gases, which will find a broad palette of applications in surface modification, plasma medicine and gas treatment, etc.

  20. Catching proteins in liquid helium droplets

    CERN Document Server

    Kupser, Peter; Meijer, Gerard; von Helden, Gert

    2010-01-01

    An experimental approach is presented that allows for the incorporation of large mass/charge selected ions in liquid helium droplets. It is demonstrated that droplets can be efficiently doped with a mass/charge selected amino acid as well as with the much bigger m$\\approx$12 000 amu protein Cytochrome C in selected charge states. The sizes of the ion-doped droplets are determined via electrostatic deflection. Under the experimental conditions employed, the observed droplet sizes are very large and range, dependent on the incorporated ion, from 10$^{10}$ helium atoms for protonated Phenylalanine to 10$^{12}$ helium atoms for Cytochrome C. As a possible explanation, a simple model based on the size- and internal energy-dependence of the pickup efficiency is given.

  1. Feasibility of lunar Helium-3 mining

    Science.gov (United States)

    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

  2. Superfluid helium-4 in one dimensional channel

    Science.gov (United States)

    Kim, Duk Y.; Banavar, Samhita; Chan, Moses H. W.; Hayes, John; Sazio, Pier

    2013-03-01

    Superfluidity, as superconductivity, cannot exist in a strict one-dimensional system. However, the experiments employing porous media showed that superfluid helium can flow through the pores of nanometer size. Here we report a study of the flow of liquid helium through a single hollow glass fiber of 4 cm in length with an open id of 150 nm between 1.6 and 2.3 K. We found the superfluid transition temperature was suppressed in the hollow cylinder and that there is no flow above the transition. Critical velocity at temperature below the transition temperature was determined. Our results bear some similarity to that found by Savard et. al. studying the flow of helium through a nanohole in a silicon nitrite membrane. Experimental study at Penn State is supported by NSF Grants No. DMR 1103159.

  3. The muonic helium lamb shift experiment

    Energy Technology Data Exchange (ETDEWEB)

    Goetzfried, Johannes; Krauth, Julian [Max-Planck-Institute of Quantum Optics, Garching (Germany); Collaboration: CREMA collaboration

    2014-07-01

    Because of its high sensitivity on finite size effects of the nucleus, the measurement of the Lamb shift in exotic atoms has been on the wish-list of atomic and nuclear physics for a long time. Our previous experiment allowed to determine the proton radius with an order of magnitude higher precision compared to spectroscopic measurements of ordinary hydrogen. The successor experiment in muonic helium is currently performed at the Paul-Scherrer-Institute in Switzerland. Using a low energy muon beam line muons are stopped within low pressure helium gas, where exotic atoms are created. Here we measure the 2S-2P transition frequency of muonic helium illuminated by a pulsed TiSa-laser system pumped with a newly developed Yb-YAG thin disk laser. This measurement will ultimately improve the values of the charge radii of {sup 3}He{sup +} and {sup 4}He{sup +} by an order of magnitude.

  4. Primary neutral helium in the heliosphere

    CERN Document Server

    Mueller, Hans-Reinhard

    2012-01-01

    Two years of neutral measurements by IBEX-Lo have yielded several direct observations of interstellar neutral helium and oxygen during preferred viewing seasons. Besides the interstellar signal, there are indications of the presence of secondary neutral helium and oxygen created in the heliosphere. Detailed modeling of these particle species is necessary to connect the measured fluxes to the pristine local interstellar medium while accounting for loss and production of neutral particles during their path through the heliosphere. In this contribution, global heliosphere models are coupled to analytic calculations of neutral trajectories to obtain detailed estimates of the neutral distribution function of primary interstellar helium atoms in the heliosphere, in particular in the inner heliosphere.

  5. Molecular Dynamics Simulations of Helium Behaviour in Titanium Crystals

    Institute of Scientific and Technical Information of China (English)

    SUN Tie-Ying; LONG Xing-Gui; WANG Jun; HOU Qing; WU Zhong-Cheng; PENG Shu-Ming; LUO Shun-Zhong

    2008-01-01

    Molecular dynamics simulations are performed to investigate the behaviour of helium atoms in titanium at a temperature of 300 K.The nucleation and growth of helium bubble has been simulated up to 50 helium atoms.The approach to simulate the bubble growth is to add helium atoms one by one to the bubble and let the system evolve.The titanium cohesion is based on the tight binding scheme derived from the embedded atom method,and the helium-titanium interaction is characterized by fitted potential in the form of a Lennard-Jones function.The pressure in small helium bubbles is approximately calculated.The simulation results show that the pressure will decrease with the increasing bubble size,while increase with the increasing helium atoms.An analytic function about the quantitative relationship of the pressure with the bubble size and number of helium atoms is also fitted.

  6. Adsorption of Helium Atoms on Two-Dimensional Substrates

    Science.gov (United States)

    Burganova, Regina; Lysogorskiy, Yury; Nedopekin, Oleg; Tayurskii, Dmitrii

    2016-12-01

    The study of the adsorption phenomenon of helium began many decades ago with the discovery of graphite as a homogeneous substrate for the investigation of physically adsorbed monolayer films. In particular, helium monoatomic layers on graphite were found to exhibit a very rich phase diagram. In the present work we have investigated the adsorption phenomenon of helium atoms on graphene and silicene substrates by means of density functional theory with Born-Oppenheimer approximation. Helium-substrate and helium-helium interactions were considered from first principles. Vibrational properties of adsorbed monolayers have been used to explore the stability of the system. This approach reproduces results describing the stability of a helium monolayer on graphene calculated by quantum Monte Carlo (QMC) simulations for low and high coverage cases. However, for the moderate coverage value there is a discrepancy with QMC results due to the lack of helium zero point motion.

  7. Adsorption of Helium Atoms on Two-Dimensional Substrates

    Science.gov (United States)

    Burganova, Regina; Lysogorskiy, Yury; Nedopekin, Oleg; Tayurskii, Dmitrii

    2016-01-01

    The study of the adsorption phenomenon of helium began many decades ago with the discovery of graphite as a homogeneous substrate for the investigation of physically adsorbed monolayer films. In particular, helium monoatomic layers on graphite were found to exhibit a very rich phase diagram. In the present work we have investigated the adsorption phenomenon of helium atoms on graphene and silicene substrates by means of density functional theory with Born-Oppenheimer approximation. Helium-substrate and helium-helium interactions were considered from first principles. Vibrational properties of adsorbed monolayers have been used to explore the stability of the system. This approach reproduces results describing the stability of a helium monolayer on graphene calculated by quantum Monte Carlo (QMC) simulations for low and high coverage cases. However, for the moderate coverage value there is a discrepancy with QMC results due to the lack of helium zero point motion.

  8. Trace Detection of Metastable Helium Molecules in Superfluid Helium by Laser-Induced Fluorescence

    CERN Document Server

    McKinsey, D N; Nikkel, J A; Rellergert, W

    2005-01-01

    We describe an approach to detecting ionizing radiation that combines the special properties of superfluid helium with the sensitivity of quantum optics techniques. Ionization in liquid helium results in the copious production of metastable helium molecules, which can be detected by laser-induced fluorescence. Each molecule can be probed many times using a cycling transition, resulting in the detection of individual molecules with high signal to noise. This technique could be used to detect neutrinos, weakly interacting massive particles, and ultracold neutrons, and to image superfluid flow in liquid He-4.

  9. Variational calculations of coupling of an incident helium atom to a slab of superfluid helium four

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, C.E.; Halley, J.W.; Hoon, S. [and others

    1995-04-01

    In previous work on the interaction of single helium atoms with a slab of superfluid helium the authors found a large amplitude, dependent on the condensate fraction, for transmission with re-emission of a helium atom at the other side of the slab. Here they report a variational formulation of the problem which permits a time dependent calculation and which does not require any perturbation expansion. The variational principle involves a minimization of the expectation value of the square of the difference H-E. They will present preliminary results of a variational Monte Carlo calculation using a simple variational form for the wave function.

  10. Extraction of Fucoxanthin from Raw Macroalgae excluding Drying and Cell Wall Disruption by Liquefied Dimethyl Ether

    Directory of Open Access Journals (Sweden)

    Hideki Kanda

    2014-04-01

    Full Text Available Macroalgae are one of potential sources for carotenoids, such as fucoxanthin, which are consumed by humans and animals. This carotenoid has been applied in both the pharmaceutical and food industries. In this study, extraction of fucoxanthin from wet brown seaweed Undaria pinnatifida (water content was 93.2% was carried out with a simple method using liquefied dimethyl ether (DME as an extractant in semi-continuous flow-type system. The extraction temperature and absolute pressure were 25 °C and 0.59 MPa, respectively. The liquefied DME was passed through the extractor that filled by U. pinnatifida at different time intervals. The time of experiment was only 43 min. The amount of fucoxanthin could approach to 390 μg/g dry of wet U. pinnatifida when the amount of DME used was 286 g. Compared with ethanol Soxhlet and supercritical CO2 extraction, which includes drying and cell disruption, the result was quite high. Thus, DME extraction process appears to be a good method for fucoxanthin recovery from U. pinnatifida with improved yields.

  11. Ataxia with Parkinsonism and dystonia after intentional inhalation of liquefied petroleum gas

    Directory of Open Access Journals (Sweden)

    Godani M

    2015-05-01

    Full Text Available Massimiliano Godani,1 Francesca Canavese,1 Sonia Migliorini,2 Massimo Del Sette1 1Neurology Unit, 2Department of Neuroradiology, Sant’Andrea Hospital, La Spezia, Italy Abstract: The practice of inhaling liquefied petroleum gas (LPG to commit suicide is uncommon and almost exclusively a prerogative of the prison population. Numerous cases of sudden deaths caused by intentional propane and/or butane inhalation have been described, but these cases survived and a description of the consequences is very rare. We describe a prisoner who survived after voluntary inhalation of LPG, and who developed ataxia, Parkinsonism, and dystonia. Brain MRI showed bilateral hyperintensity in the basal ganglia and in the cerebellar hemispheres. The clinical evolution and the MRI abnormalities are similar to those described in cases of poisoning by CO where the mechanism of brain injury is related to histotoxic hypoxia. We believe that LPG, considered until now a mixture of gas with low neurotoxic power, may have caused direct toxic damage to the brain, mediated by a mechanism of hypoxia, such as in CO intoxication. Keywords: ataxia, Parkinsonism, dystonia, liquefied petroleum gas

  12. Helium and Sulfur Hexafluoride in Musical Instruments

    Science.gov (United States)

    Forinash, Kyle; Dixon, Cory L.

    2014-01-01

    The effects of inhaled helium on the human voice were investigated in a recent article in "The Physics Teacher." As mentioned in that article, demonstrations of the effect are a popular classroom activity. If the number of YouTube videos is any indication, the effects of sulfur hexafluoride on the human voice are equally popular.…

  13. Photoassociation of cold metastable helium atoms

    NARCIS (Netherlands)

    Woestenenk, G.R.

    2001-01-01

    During the last decades the study of cold atoms has grown in a great measure. Research in this field has been made possible due to the development of laser cooling and trapping techniques. We use laser cooling to cool helium atoms down to a temperature of 1 mK and we are able to tr

  14. Critical Landau Velocity in Helium Nanodroplets

    NARCIS (Netherlands)

    N.B. Brauer; S. Smolarek; E. Loginov; D. Mateo; A. Hernando; M. Pi; M. Barranco; W.J. Buma; M. Drabbels

    2013-01-01

    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 excitatio

  15. Messer to provide helium for LHC

    CERN Document Server

    2008-01-01

    Over the course of the next few years, industrial gas specialist The Messer Group, through its Swiss subsidiary Messer Schweiz AG, is to provide a 160,000kg supply of helium to the European Organisation for Nuclear Research (CERN) for the operation of the world's largest particle accelerator.

  16. Messer to provide helium for LHC project

    CERN Multimedia

    2008-01-01

    Over the course of the next few years, industrial gas specialist The Messer Group, through its Swiss subsidiary Messer Schweiz AG, is to provide a 160,000kg supply of helium to the European Organisation for Nuclear Research (CERN) for the operation of the world's largest particle accelerator.

  17. Thermalization of magnetically trapped metastable helium

    CERN Document Server

    Browaeys, A; Sirjean, O; Poupard, J; Nowak, S; Boiron, D; Westbrook, C I; Aspect, Alain

    2001-01-01

    We have observed thermalization by elastic collisions of magnetically trapped metastable helium atoms. Our method directly samples the reconstruction of a thermal energy distribution after the application of an RF knife. The relaxation time of our sample towards equilibrium gives an elastic collision rate constant close to the unitarity limit.

  18. Femtosecond spectroscopy on alkali-doped helium nanodroplets; Femtosekundenspektroskopie an alkalidotierten Helium-Nanotroepfchen

    Energy Technology Data Exchange (ETDEWEB)

    Claas, P.

    2006-01-15

    In the present thesis first studies on the short-time dynamics in alkali dimers and microclusters, which were bound on the surface of superfluid helium droplets, were presented. The experiments comprehended pump-probe measurements on the fs scale on the vibration dynamics on the dimers and on the fragmentation dynamics on the clusters. Generally by the studies it was shown that such extremely short slopes can also be observed on helium droplets by means of the femtosecond spectroscopy.

  19. Development of a helium cryostat for laser spectroscopy of atoms with unstable nuclei in superfluid helium

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, Kei, E-mail: kimamura@riken.jp [Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571 (Japan); Furukawa, Takeshi [Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakui, Takashi [Cyclotron and Radioisotope Center, Tohoku University, 6-3 Aoba, Aramaki, Aoba, Sendai, Miyagi 980-8578 (Japan); Yang, Xiaofei [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); School of Physics, Peking University, Chengfu Road, Haidian District, Beijing 100871 (China); Yamaguchi, Yasuhiro [Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571 (Japan); Tetsuka, Hiroki [Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Mitsuya, Yosuke [Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571 (Japan); Tsutsui, Yoshiki [Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Fujita, Tomomi [Department of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Ebara, Yuta; Hayasaka, Miki [Department of Physics, Tokyo Gakugei University, 4-1-1 Nukuikitamachi, Koganei, Tokyo 184-8501 (Japan); Arai, Shino; Muramoto, Sosuke [Department of Physics, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki, Kanagawa 214-8571 (Japan); Ichikawa, Yuichi [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tokyo Instutute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan); Ishibashi, Yoko [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); and others

    2013-12-15

    We are developing a new nuclear laser spectroscopic technique for the study of nuclear structure that can be applied to short-lived low-yield atoms with unstable nuclei. The method utilizes superfluid helium (He II) as a trapping medium for high-energy ion beams. A liquid helium cryostat with optical windows is a key apparatus for this type of experiment. We describe the design and the performance of the cryostat which is developed for the present project.

  20. Idea on safety of large-sized liquefied oxygen and liquefied nitrogen tank%对大型液氧、液氮贮槽安全的思考

    Institute of Scientific and Technical Information of China (English)

    马大方

    2012-01-01

    简述大型液氧、液氮贮槽的常规安全措施,结合大型低温液体贮槽的爆炸事故,阐述在排液口设置重锤式快速切断阀和顶盖设计为薄弱结构的必要性及其作用,分析在大型液氧、液氮贮槽槽区不设安全围堰的可行性。%The routine safety measures for large-sized liquefied oxygen and liquefied nitrogen tank are briefed. In combination with explosion accident of large-sized low-temperature liquid tank, the necessity to set a harmer type quick cut off valve at drain port and design the top cover as a weak structure and their reached effects are described, and the feasibility not to set a safe weir in the large-sized liquefied oxygen and liquefied nitrogen tank is analyzed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pentlehner, D.; Slenczka, A., E-mail: alkwin.slenczka@chemie.uni-regensburg.de [Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg (Germany)

    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 broad (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.

  2. Helium accreting CO white dwarfs with rotation: helium novae instead of double detonation

    CERN Document Server

    Yoon, S C

    2004-01-01

    We present evolutionary models of helium accreting carbon-oxygen white dwarfs in which we include the effects of the spin-up of the accreting star induced by angular momentum accretion, rotationally induced chemical mixing and rotational energy dissipation. Initial masses of 0.6 Msun and 0.8 Msun and constant accretion rates of a few times 10^{-8} Msun/yr of helium rich matter have been considered, which is typical for the sub-Chandrasekhar mass progenitor scenario for Type Ia supernovae. It is found that the helium envelope in an accreting white dwarf is heated efficiently by friction in the differentially rotating spun-up layers. As a result, helium ignites much earlier and under much less degenerate conditions compared to the corresponding non-rotating case. Consequently, a helium detonation may be avoided, which questions the sub-Chandrasekhar mass progenitor scenario for Type Ia supernovae. We discuss implications of our results for the evolution of helium star plus white dwarf binary systems as possible...

  3. POSSIBILITY FOR APPLICATION OF LIQUEFIED GASES FOR PURIFICATION OF BARBERRY ALKALOIDS

    Directory of Open Access Journals (Sweden)

    Demyanenko D.V.

    2016-06-01

    Full Text Available Introduction. Biologically active substances (BAS of barberry roots represented by alkaloids of isoquinoline group are perspective substances for development of preparations with multiple pharmacological activities. However, now manufacture of them in Ukraine is stopped. One of the reasons of this is out-of-date production technologies of alkaloids involving use of toxic and/or flammable solvents. In the article possibility for application of liquefied gases in technology of obtaining of alkaloids from barberry roots has been studied. Materials and methods. Initial raw herb drug were barberry (Berberis vulgaris roots harvested in spring on the territory of Southern Ukraine. Their moisture content was 11%, comminuting degree was 0,5-1,4 mm. At the first stage purification of raw herb drug from lipophilic impurities (defatting was made with use of some liquefied gases: tetrafluoroethane, isobutane, difluorochloromethane and difluoromethane. Extraction of the alkaloid sum was made with difluoromethane mixed with various quantities of liquid ammonia or diethylamine as alkaline agent. Crude extracts were exposed to two-level liquefied-gas purification. At first the alkaloid bases were transformed into saline forms with aqueous solutions of acids and purified from ballast impurities with liquefied freon-22. Then alkaloid salts were reextracted from aqueous phase in the base form with liquefied mixture of difluoromethane and ammonia. Mixing of liquid phases was provided by creation of alternate gradients of temperatures and, as consequence, pressures between separators feeding alternately cool water into jacket of one of them, and warm water – into jacket of another one. Quantity of lipophilic ballast impurities and also weight of extractives were determined gravimetrically. Quantitative analysis of the alkaloid sum was made by titrimetric method after sedimentation of alkaloids with volumetric solution of phosphomolybdic acid. Results and discussion

  4. Evaluation of helium cooling for fusion divertors

    Energy Technology Data Exchange (ETDEWEB)

    Baxi, C.B.

    1993-09-01

    The divertors of future fusion reactors will have a power throughput of several hundred MW. The peak heat flux on the diverter surface is estimated to be 5 to 15 MW/m{sup 2} at an average heat flux of 2 MW/m{sup 2}. The divertors have a requirement of both minimum temperature (100{degrees}C) and maximum temperature. The minimum temperature is dictated by the requirement to reduce the absorption of plasma, and the maximum temperature is determined by the thermo-mechanical properties of the plasma facing materials. Coolants that have been considered for fusion reactors are water, liquid metals and helium. Helium cooling has been shown to be very attractive from safety and other considerations. Helium is chemically and neutronically inert and is suitable for power conversion. The challenges associated with helium cooling are: (1) Manifold sizes; (2) Pumping power; and (3) Leak prevention. In this paper the first two of the above design issues are addressed. A variety of heat transfer enhancement techniques are considered to demonstrate that the manifold sizes and the pumping power can be reduced to acceptable levels. A helium-cooled diverter module was designed and fabricated by GA for steady-state heat flux of 10 MW/m{sup 2}. This module was recently tested at Sandia National Laboratories. At an inlet pressure of 4 MPa, the module was tested at a steady-state heat flux of 10 MW/m{sup 2}. The pumping power required was less than 1% of the power removed. These results verified the design prediction.

  5. 76 FR 2093 - Eni USA Gas Marketing LLC; Application for Blanket Authorization To Export Liquefied Natural Gas

    Science.gov (United States)

    2011-01-12

    ... Gas Marketing LLC; Application for Blanket Authorization To Export Liquefied Natural Gas AGENCY... November 30, 2010, by Eni USA Gas Marketing LLC (Eni USA), requesting blanket authorization to export... and Gas Global Security and Supply, Office of Fossil Energy, Forrestal Building, Room 3E-042,...

  6. 78 FR 75339 - Barca LNG LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced...

    Science.gov (United States)

    2013-12-11

    ... LNG LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas Produced From..., by Barca LNG LLC (Barca), requesting long-term, multi- contract authorization to export LNG produced...) of natural gas, or 1.6 Bcf per day (Bcf/d). Barca seeks authorization to export the LNG for a...

  7. 77 FR 55197 - LNG Development Company, LLC; Application for Long-Term Authorization To Export Liquefied Natural...

    Science.gov (United States)

    2012-09-07

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY LNG...) filed on July 16, 2012, by LNG Development Company, LLC (d/b/a Oregon LNG), requesting long-term, multi-contract authorization to export up to 9.6 million tons per annum (mtpa) of liquefied natural gas...

  8. 76 FR 76698 - Dominion Cove Point LNG, LP; Application To Export Domestic Liquefied Natural Gas to Non-Free...

    Science.gov (United States)

    2011-12-08

    ...] [FR Doc No: 2011-31518] DEPARTMENT OF ENERGY [FE Docket No. 11-128-LNG] Dominion Cove Point LNG, LP..., by Dominion Cove Point LNG, LP (DCP), requesting long- term, multi-contract authorization to export up to 7.82 million metric tons per year of domestically produced liquefied natural gas...

  9. 49 CFR 173.304b - Additional requirements for shipment of liquefied compressed gases in UN pressure receptacles.

    Science.gov (United States)

    2010-10-01

    ... compressed gases in UN pressure receptacles. 173.304b Section 173.304b Transportation Other Regulations...; Preparation and Packaging § 173.304b Additional requirements for shipment of liquefied compressed gases in UN... UN pressure receptacles subject to the requirements in this section and § 173.304. In addition,...

  10. Molecular dynamics study of helium bubble pressure in titanium

    Institute of Scientific and Technical Information of China (English)

    Zhang Bao-Ling; Wang Jun; Hou Qing

    2011-01-01

    In this paper, the pressure state of the helium bubble in titanium is simulated by a molecular dynamics (MD) method. First, the possible helium/vacancy ratio is determined according to therelation between the bubble pressure and helium/vacancy ratio; then the dependences of the helium bubble pressure on the bubble radius at different temperatures are studied. It is shown that the product of the bubble pressure and the radius is approximately a constant, a result justifying the pressure-radius relation predicted by thermodynamics-based theory for gas bubble. Furthermore, a state equation of the helium bubble is established based on the MD calculations. Comparison between the results obtained by the state equation and corresponding experimental data shows that the state equation can describe reasonably the state of helium bubble and thus could be used for Monte Carlo simulations of the evolution of helium bubble in metals.

  11. Liquefied Natural Gas (LNG) project: a tax overview; Projeto Gas Natural Liquefeito (GNL): uma abordagem tributaria

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Claudia W.M.; Faria, Viviana C.S. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    In the second semester of 2008, the Liquefied Natural Gas (LNG) will be introduced in the Brazilian energy matrix, it will be done through an innovator project according technical and tax points of view. Mentioned the enormous effort of adapting the federal legislation approved for this new activity which begins in the country, uncharged both the admission of the vessel as the import of the commodity in the incidence of federal taxes. The market for LNG demand simplified customs procedures in order to benefit from the dynamism that this industry offers, and in addition, a tax burden that encourages the use of a competitive and compatible with the precepts of sustainable development of the country. (author)

  12. Brazilian liquefied natural gas terminals: from the conception to the operation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Renata N.R. dos; Lemos, Marcelo C. de; Silva, Marcos Jose M. da; Borges, Jorge Luiz P.; Soares, Fabio L.; Grieco, Eduardo P.; Melchior, Jose Carlos [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil)

    2009-12-19

    To guarantee more flexibility and safety in supplying natural gas to the Brazilian market, PETROBRAS designed and constructed two liquefied natural gas (LNG) regasification terminals. These terminals are unprecedented in the world since they are the only ones to use vessels that have been adapted to store LNG and re gasify the product onboard and to adopt the model of transferring LNG from a supply ship to a regasification vessel via cryogenic arms. Due to these different characteristics, TRANSPETRO, the PETROBRAS subsidiary in charge of operating these terminals, had to prepare itself not only to deal with a new product but also to operate terminals that have no counterparts in the world. This article gives an overview of the LNG supply chain and of the new Brazilian LNG Terminals from their conception to the preparation process to operate them. (author)

  13. Impacts of Imported Liquefied Natural Gas on Residential Appliance Components: Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Lekov, Alex; Sturges, Andy; Wong-Parodi, Gabrielle

    2009-12-09

    An increasing share of natural gas supplies distributed to residential appliances in the U.S. may come from liquefied natural gas (LNG) imports. The imported gas will be of a higher Wobbe number than domestic gas, and there is concern that it could produce more pollutant emissions at the point of use. This report will review recently undertaken studies, some of which have observed substantial effects on various appliances when operated on different mixtures of imported LNG. While we will summarize findings of major studies, we will not try to characterize broad effects of LNG, but describe how different components of the appliance itself will be affected by imported LNG. This paper considers how the operation of each major component of the gas appliances may be impacted by a switch to LNG, and how this local impact may affect overall safety, performance and pollutant emissions.

  14. Solid-state titania-based gas sensor for liquefied petroleum gas detection at room temperature

    Indian Academy of Sciences (India)

    B C Yadav; Anuradha Yadav; Tripti Shukla; Satyendra Singh

    2011-12-01

    This paper reports the liquefied petroleum gas (LPG) sensing of titanium dioxide (Qualigens, India). Scanning electron micrographs and X-ray diffraction studies of samples were done. SEM shows that the material is porous and has grapes-like morphology before exposure to the LPG. XRD patterns reveal the crystalline nature of the material. The crystallites sizes of the TiO2 were found in the range of 30–75 nm. Variations in resistance with exposure of LPG to the sensing element were observed. The average sensitivity for different volume percentages of gas was estimated. The maximum value of average sensitivity was 1.7 for higher vol.% of LPG. Percentage sensor response (%SR) as a function of time was calculated and its maximum value was 45%. Response time of the sensor was 70 s. The sensor was quite sensitive to LPG and results were found reproducible.

  15. Liquefaction of bamboo,preparation of liquefied bamboo adhesives,and properties of the adhesives

    Institute of Scientific and Technical Information of China (English)

    Fu Shenyuan; Ma Lingfei; Li Wenzhu; Cheng Shuna

    2006-01-01

    This study investigated the liquefaction of bamboo in phenol,which involved the effects of weight ratios of phenol to bamboo,amount of catalyst,temperature,etc.The study showed that liquefaction could be accomplished with a phenol to bamboo weight ratio of 2-1:1,a 5% catalyst of HCI or BF3,and a temperature of 1150C.Liquefied bamboo formaldehyde (BLF) resin adhesive for exterior use could be obtained with a phenol to formaldehyde molar ratio of 1:1.6-2.0.The curing behavior of BLF resin adhesive,studied by TG-DSC and IR analyses,showed that BLF resin adhesives had a lower curing temperature than PF adhesives but had the same characteristic trough in IR spectra as PF adhesives.

  16. Uplifting behavior of shallow buried pipe in liquefiable soil by dynamic centrifuge test.

    Science.gov (United States)

    Huang, Bo; Liu, Jingwen; Lin, Peng; Ling, Daosheng

    2014-01-01

    Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure.

  17. Uplifting Behavior of Shallow Buried Pipe in Liquefiable Soil by Dynamic Centrifuge Test

    Directory of Open Access Journals (Sweden)

    Bo Huang

    2014-01-01

    Full Text Available Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure.

  18. LNG (Liquefied Natural Gas): emerging control; GNL (Gas Natural Liquefeito): controle de emergencia

    Energy Technology Data Exchange (ETDEWEB)

    Berardinelli, Ricardo Porto; Correa, Kleber Macedo; Moura Filho, Nelson Barboza de; Matos, Jose Eduardo Nogueira de; Fernandez, Carlos Antonio [TRANSPETRO, Rio de Janeiro, RJ (Brazil). Gerencia de Seguranca, Meio Ambiente e Saude

    2008-07-01

    The operation to Liquefied Natural Gas (LNG) is innovative for the PETROBRAS System. PETROBRAS Transporte - TRANSPETRO will operate two LNG flexible terminals. In accordance with the health, safety and environmental policy - training, education and awareness action plans were formulated by TRANSPETRO to assure the operational safety for the activity. Part of this action plan includes the training of LNG spill control and fire suppression. The training was carried out in 20 hours and divided into two parts: theoretical and practice. In the practice part, 3.000 gallons of LNG were unloaded and the students could verify the behaviour of the LNG and the effectiveness of the resources available for the emergency control. The knowledge was introduced in the company to create specific procedures, local emergency plans and develop internal instructors. (author)

  19. Liquefied gaseous fuels safety and environmental control assessment program: third status report

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-01

    This Status Report contains contributions from all contractors currently participating in the DOE Liquefied Gaseous Fuels (LG) Safety and Environmental Control Assessment Program and is presented in two principal sections. Section I is an Executive Summary of work done by all program participants. Section II is a presentation of fourteen individual reports (A through N) on specific LGF Program activities. The emphasis of Section II is on research conducted by Lawrence Livermore National Laboratory (Reports A through M). Report N, an annotated bibliography of literature related to LNG safety and environmental control, was prepared by Pacific Northwest Laboratory (PNL) as part of its LGF Safety Studies Project. Other organizations who contributed to this Status Report are Aerojet Energy Conversion Company; Applied Technology Corporation; Arthur D. Little, Incorporated; C/sub v/ International, Incorporated; Institute of Gas Technology; and Massachusetts Institute of Technology. Separate abstracts have been prepared for Reports A through N for inclusion in the Energy Data Base.

  20. Semi-analytical models of hydroelastic sloshing impact in tanks of liquefied natural gas vessels.

    Science.gov (United States)

    Ten, I; Malenica, Š; Korobkin, A

    2011-07-28

    The present paper deals with the methods for the evaluation of the hydroelastic interactions that appear during the violent sloshing impacts inside the tanks of liquefied natural gas carriers. The complexity of both the fluid flow and the structural behaviour (containment system and ship structure) does not allow for a fully consistent direct approach according to the present state of the art. Several simplifications are thus necessary in order to isolate the most dominant physical aspects and to treat them properly. In this paper, choice was made of semi-analytical modelling for the hydrodynamic part and finite-element modelling for the structural part. Depending on the impact type, different hydrodynamic models are proposed, and the basic principles of hydroelastic coupling are clearly described and validated with respect to the accuracy and convergence of the numerical results.

  1. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Shestakov Igor A.

    2015-01-01

    Full Text Available The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characterize the basic regularities of the processes are obtained. Circulating flows are determined and carried out the analysis of vortices formation mechanism and the temperature distribution in solution at conditions of natural convection when the Grashof number (Gr = 106. A significant influence of heat transfer rate on solutions boundary on flow structure and temperature field in LNG storage tanks.

  2. Estimation on Global Reaction Heat for the Aromatization Process of Liquefied Petroleum Gas

    Institute of Scientific and Technical Information of China (English)

    黎小辉; 朱建华; 郝代军

    2013-01-01

    The reaction heat effect analysis for the aromatization process of Liquefied Petroleum Gas (LPG) was completed in this paper. In order to characterize this complex reaction system, one set of independent reactions was determined by means of atomic coefficient matrix method. Based on reaction thermodynamic and stoichiometric knowledge, the heat effect, Gibbs free energy change and equilibrium constant for each independent reaction was calculated for the specified conditions. Under these conditions, based on the initial and final composition data from LPG aromatization experiments, the actual extent of reaction for each independent reaction was determined. Fur-thermore, the global reaction heat and adiabatic temperature rise of LPG aromatization reaction system could be es-timated. This work would provide a theoretical guidance for the design and scale-up of reactor for LPG aromatiza-tion process, as well as for the selection of proper operating conditions.

  3. Radial Evolution of the Atmospheric Pressure Glow Discharge in Helium Controlled by Dielectric Barrier

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yuan-Tao; WANG De-Zhen; WANG Yan-Hui; LIU Cheng-Sen

    2005-01-01

    @@ The radial evolution of atmospheric pressure glow discharge in helium is presented by numerical simulation. The calculations reveal the mechanism of two current peaks per half cycle. The first breakdown occurs firstly in the central region of the electrode, and then spreads to the edge, while the second breakdown ignites at the periphery firstly, and then propagates toward the discharge central region. The simulations indicate that radial electric fields and radial sheath play an important role in the evolution of the second peak. These results agree fundamentally with the experimental observations.

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

    Science.gov (United States)

    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.

  5. Supernovae from Direct Collisions of White Dwarfs and the Role of Helium Shell Ignition

    Science.gov (United States)

    Papish, Oded; Perets, Hagai Binyamin

    2016-05-01

    Models for supernovae (SNe) arising from thermonuclear explosions of white dwarfs (WDs) have been studied extensively over the past few decades, mostly focusing on the single-degenerate (accretion of material by a WD) and double-degenerate (WD-WD merger) scenarios. In recent years it was suggested that direct WD-WD collisions provide an additional channel for such explosions. Here we extend the studies of such explosions and explore the role of helium shells in affecting the thermonuclear explosions. We study the impact of both low-mass (˜0.01 M ⊙) and high-mass (≥0.1 M ⊙) helium shells. We find that detonation of the massive helium layers precedes the detonation of the WD carbon-oxygen (CO) bulk during the collision and can change the evolution of the explosion and the outcomes for the cases of high-mass He shells. In particular, the He shell detonation propagates on the WD surface and inefficiently burns material prior to the CO detonation that later follows in the central parts of the WD. Such evolution leads to greater production of intermediate elements, producing larger yields of 44Ti and 48Cr relative to the pure CO-CO WD collisions. Collisions of WDs with a low-mass He shell do not give rise to helium detonation, but helium burning does precede the CO bulk detonation. Such collisions eject at high velocity a low mass of burned material enriched with intermediate elements and produce smaller changes in the overall explosion outcomes. The various effects arising from the contribution of low-/high-mass He layers change the kinematics and the morphological structure of collision-induced SNe and may thereby provide unique observational signatures for such SNe and play a role in the chemical enrichment of galaxies and the production of intermediate elements and positrons from their longer-term decay.

  6. 液化地基中群桩基础地震响应分析%Seismic response analysis of pile groups in liquefiable foundations

    Institute of Scientific and Technical Information of China (English)

    刘星; 王睿; 张建民

    2015-01-01

    可液化地基中桩基础地震响应分析一直是岩土工程抗震研究的热点和难点。针对这一问题,采用砂土液化大变形统一本构模型来描述可液化地基土体的应力应变关系,建立了一个3×5的群桩三维计算模型,采用三维弹塑性有限元动力时程分析,将地基、群桩基础和上部结构作为一个系统研究群桩基础的地震动响应规律,重点关注桩与土的运动相互作用以及水平方向的弯矩在地震荷载作用下的分配情况。结果表明可液化地基中桩基础的弯矩受桩与土运动相互作用影响显著;不同桩的弯矩最大值不同,角桩最大,边桩次之,中心桩最小;弯矩最大值出现的位置不相同,角桩和边桩弯矩最大值出现在上部非液化层与液化层界面处,中心桩弯矩最大值出现在桩头处。%The seismic analysis of pile foundations in liquefiable ground is an important subject in geotechnical earthquake engineering. A computational model of a 3×5 pile group is established in OpenSees FEM program, and considering soil foundations, the pile group and the upper structure as a system, a unified plastic constitutive model for large post-liquefaction deformation of sand is employed. Special attention is given to the kinematic interaction between piles and soil and distribution of the moment in pile groups. The results show that the soil-pile kinematic interaction has a significant influence on the moment of piles in liquefiable ground. The moment distribution in pile groups indicates that the maximum moment of the corner piles is the largest, and that of the central piles is the smallest. The positions of the maximum moment of different piles are different. The maximum moments in the corner piles and the edge piles are at the interface between the upper layer and the liquefied layer, but the maximum moment in the central piles is at the pile top.

  7. Survivor from asphyxiation due to helium inhalation

    Directory of Open Access Journals (Sweden)

    Massimiliano Etteri

    2016-06-01

    Full Text Available In this rare case report we describe a 27- year-old white man survived to suicide by asphyxiation using the so-called suicide bag (or exit bag filled with helium supplied through a plastic tube. He had no previous psychiatric or organic illnesses. At the time of presentation to our Emergency Department he was awake and reported severe dyspnea with a clinical pattern of acute respiratory failure. Imaging studies showed pulmonary edema and the patient was treated with non-invasive ventilation in Intensive Care Unit. After 15 days the patient was discharged from hospital in optimal conditions. These rare cases of survivor might suggest the possible causes of death from inhaling helium.

  8. Correlation of Helium Solubility in Liquid Nitrogen

    Science.gov (United States)

    VanDresar, Neil T.; Zimmerli, Gregory A.

    2012-01-01

    A correlation has been developed for the equilibrium mole fraction of soluble gaseous helium in liquid nitrogen as a function of temperature and pressure. Experimental solubility data was compiled and provided by National Institute of Standards and Technology (NIST). Data from six sources was used to develop a correlation within the range of 0.5 to 9.9 MPa and 72.0 to 119.6 K. The relative standard deviation of the correlation is 6.9 percent.

  9. Laser Spectroscopy of Antiprotonic Helium Atoms

    CERN Multimedia

    2002-01-01

    %PS205 %title\\\\ \\\\Following the discovery of metastable antiprotonic helium atoms ($\\overline{p}He^{+} $) at KEK in 1991, systematic studies of their properties were made at LEAR from 1991 to 1996. In the first two years the lifetime of $\\overline{p}He^{+}$ in liquid and gaseous helium at various temperatures and pressures was measured and the effect of foreign gases on the lifetime of these atoms was investigated. Effects were also discovered which gave the antiproton a 14\\% longer lifetime in $^4$He than in $^3$He, and resulted in important differences in the shape of the annihilation time spectra in the two isotopes.\\\\ \\\\Since 1993 laser spectroscopy of the metastable $\\overline{p}He^{+}$ atoms became the main focus of PS205. Transitions were stimulated between metastable and non-metastable states of the $\\overline{p}He^{+}$ atom by firing a pulsed dye laser beam into the helium target every time an identified metastable atom was present (Figure 1). If the laser frequency matched the transition energy, the...

  10. Spectral line shifts of alkali atoms in liquid helium: a relativistic density functional approach

    Energy Technology Data Exchange (ETDEWEB)

    Anton, J [Universitaet Kassel, Institut fuer Physik, 34109 Kassel (Germany); Mukherjee, P K [Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032 (India); Fricke, B [Universitaet Kassel, Institut fuer Physik, 34109 Kassel (Germany); Fritzsche, S [Universitaet Kassel, Institut fuer Physik, 34109 Kassel (Germany)

    2007-06-28

    Excitation line shifts of the principal resonance transitions in alkali atoms sodium and cesium embedded inside the liquid helium environment have been calculated using four-component relativistic density functional theory. The effect of the liquid helium environment is assumed to be represented by a cluster of 14 atoms surrounding the central alkali atom. The estimated blue shift of the principal resonance line {sup 2}S {yields}{sup 2}P is 22.8 nm for Na and 16.7 nm for Cs. The result for Cs is in good agreement with the experimental shift of 18.2 nm. In the absence of the experimental data for Na, our result is compared with those of other theoretical estimates.

  11. Diffusion behaviors of helium atoms at two Pd grain boundaries

    Institute of Scientific and Technical Information of China (English)

    XIA Ji-xing; HU Wang-yu; YANG Jian-yu; AO Bing-yun

    2006-01-01

    The diffusion behaviors of helium atoms at two symmetric grain boundaries (Σ5{210} and Σ3 {112}) of Pd were investigated using molecular dynamics simulations through an analytical embedded-atom method(MAEAM) model. The simulations demonstrate that the interstitial helium atoms are easily trapped at the grain boundaries and precipitated into clusters. Due to the closed-shell electronic configurations of both helium and palladium,Pd grain boundaries yield strong capability of retaining helium atoms. By calculating the mean square displacements(MSD) of an interstitial helium atom at the grain boundaries,the diffusion coefficients were determined,and the linear fits to Arrhenius relation. The diffusion activation energies of interstitial helium atom at these two Pd grain boundaries were also evaluated.

  12. THERMAL UNIFORMITY OF LIQUID HELIUM IN ELECTRON BUBBLE CHAMBER.

    Energy Technology Data Exchange (ETDEWEB)

    WANG,L.; JIA,L.

    2002-07-22

    A CRYOGENIC RESEARCH APPARATUS TO MEASURE THE MOVEMENT OF ELECTRONS UNDER A HIGH ELECTRIC FIELD IN A LIQUID HELIUM BATH WAS DESIGNED AND BUILT AT THE BROOKHAVEN NATIONAL LABORATORY AND THE NEVIS LABORATORY OF COLUMBIA UNIVERSITY. THE LIQUID HELIUM CHAMBER IS A DOUBLE WALLED CYLINDRICAL CONTAINER EQUIPPED WITH 5 OPTICS WINDOWS AND 10 HIGH VOLTAGE CABLES. TO SHIELD THE LIQUID HELIUM CHAMBER AGAINST THE EXTERNAL HEAT LOADS AND TO PROVIDE THE THERMAL UNIFORMITY IN THE LIQUID HELIUM CHAMBER, THE DOUBLE WALLED JACKET WAS COOLED BY A PUMPED HELIUM BATH. THE HELIUM CHAMBER WAS BUILT INTO A COMMERICAL LN2 / LHE CRYOSTAT. THIS PAPER PRESENTS THE DESIGN AND THE NUMERICAL SIMULATION ANALYSIS ON THERMAL UNIFORMITY OF THE ELECTRON BUBBLE CHAMBER.

  13. Design of the Helium Purifier for IHEP-ADS Helium Purification System

    CERN Document Server

    Jianqin, Zhang; Zhuo, Zhang; Rui, Ge

    2015-01-01

    Helium Purification System is an important sub-system in the Accelerator Driven Subcritical System of the Institute of High Energy Physics(IHEP ADS). The purifier is designed to work at the temperature of 77K. The purifier will work in a flow rate of 5g/s at 20MPa in continuous operation of 12 hours. The oil and moisture are removed by coalescing filters and a dryer, while nitrogen and oxygen are condensed by a phase separator and then adsorbed in several activated carbon adsorption cylinders. After purification, the purified helium has an impurity content of less than 5ppm.

  14. Asteroseismic estimate of helium abundance of 16 Cyg A, B

    Directory of Open Access Journals (Sweden)

    Verma Kuldeep

    2015-01-01

    Full Text Available The helium ionization zone in a star leaves a characteristic signature on its oscillation frequencies, which can be used to estimate the helium content in the envelope of the star. We use the oscillation frequencies of 16 Cyg A and B, obtained using 2.5 years of Kepler data, to estimate the envelope helium abundance of these stars. We find the envelope helium abundance to lie in the range 0.231–0.251 for 16 Cyg A and 0.218–0.266 for 16 Cyg B.

  15. Helium vs. Proton Induced Displacement Damage in Electronic Materials

    Science.gov (United States)

    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.

  16. Operation modes research of liquefied natural gas storages as a part of the ground complexes equipment

    Directory of Open Access Journals (Sweden)

    N. S. Korolev

    2014-01-01

    Full Text Available The use of the Liquefied Natural Gas (LNG in the space-rocket equipment is motivated by some advantages. That is why a lot of tests and works are actively carried out now on rocket engines using liquefied natural gas.To provide the engine tests and subsequent rocket complex operation a creation of LNG storages is demanded as a part of ground processing equipment and support for their safe operation conditions.One of LNG danger factor is its low boiling temperature, and also changing the condition, density and LNG boiling temperature at storage due to evaporation of light component, namely methane. At refill of the storages having fuel remains with a new LNG portion these factors can lead to formation of the stratified macro-layers and cause a mode of the intensive mixing that is called "rollover", with almost instant evaporation of LNG big mass and sharp pressure boost, capable to result in the storage distraction with catastrophic effects.The work objectives are formulated such as a technique development for forecasting of the LNG parameters in operating storages including the rollover mode, a comparison of calculated results of the LNG parameters with the experimental data, and a definition of possible recommendations for safe operation of LNG storages as a part of the ground complexes equipment.The paper reviews 12 publications concerning the issues and proceeding processes at operation of LNG storages, including the rollover mode.To verify the reliability of process simulation results in the LNG, represented in models by the binary methane-ethane mixture the calculated values have been compared with the experimental data for a LNG storage mode in the reservoir of a ground test complex.The reliability of developed models of the heat-mass-exchange processes in stratified on density and temperature in LNG storage with emergence of conditions for the rollover mode has been verified by comparing the settlement characteristics to the published

  17. Risks associated to liquefied petroleum gas: evaluation and management; Riscos do gas liquefeito de petroleo: avaliacao e gerenciamento

    Energy Technology Data Exchange (ETDEWEB)

    Camacho Gonzalez, Amelia Beatriz [Universidad Nacional de Ingenieria, Lima (Peru). Facultad de Ingenieria Ambiental; Rocha, Aristides Almeida [Sao Paulo Univ., SP (Brazil). Faculdade de Saude Publica

    1997-07-01

    This work presents the discussion and evaluation of the environmental risks related to the use of liquefied petroleum gas (GLP) when the safety standards and proceedings are not obeyed. It also presents a bibliographic review mainly concerning the actual legislation and a case study in a industrial plant. The methodologies used in such a study are based in the HAZOP and WHAZAM models. (author) 15 refs., 2 figs.

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

    CERN Document Server

    Bulanov, S S; Schroeder, C B; Leemans, W P; Bulanov, S V; Margarone, D; Korn, G; Haberer, T

    2015-01-01

    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. This fact along with the larger biological damage to cancer cells achieved by helium ions, than that by protons, makes this 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 ...

  19. Ceramic helium-cooled blanket test module

    Energy Technology Data Exchange (ETDEWEB)

    Leshukov, A. E-mail: leshu@entek.ru; Kovalenko, V.; Shatalov, G.; Goroshkin, G.; Obukhov, A

    2000-11-01

    The design of RF DEMO-relevant ceramic helium cooled blanket test module (CHC BTM) for testing in international thermonuclear experimental reactor (ITER) is under consideration. The RF concept of DEMO BTM is based upon the breeder inside tube (BIT)-concept. This concept suggests the use of solid breeding ceramic material, helium as coolant and tritium purge-gas, ferrite-martensite steel as structural material, and beryllium as neutron multiplier. The parameters of the primary circuit coolant are the following, pressure -8 MPa, inlet/outlet temperature -300/550 deg. C, respectively. Helium (0.1 MPa pressure) is used for tritium removal from ceramic breeder. The ITER water coolant is the secondary circuit coolant of DEMO BTM cooling system. Lithium orthosilicate (Li{sub 4}SiO{sub 4}) is used as tritium breeding material (pebbles-bed of diameter 0.5-1 mm spheres). It is planned to use the beryllium as neutron multiplier (spheres diameter 1 mm pebbles-bed or the porous beryllium). The 3-D neutronic calculations on Monte Carlo method, in accordance with FENDL-1 library of the nuclear data, have been performed for CHC BTM. To validate the CHC BTM concept, the thermal hydraulic analysis has been performed for the design elements and cooling system equipment. The preliminary stress analysis for BTM design elements has been carried out on the ASME-code and RF strength regulations. The four types of LOFA and LOCA accidents have been investigated. The parameters of cooling, coolant purification and tritium extraction systems have been determined.

  20. Variable helium diffusion characteristics in fluorite

    Science.gov (United States)

    Wolff, R.; Dunkl, I.; Kempe, U.; Stockli, D.; Wiedenbeck, M.; von Eynatten, H.

    2016-09-01

    Precise analysis of the diffusion characteristics of helium in fluorite is crucial for establishing the new fluorite (U-Th-Sm)/He thermochronometer (FHe), which potentially provides a powerful tool for dating ore deposits unsuitable for the application of conventional geochronometers. Incremental helium outgassing experiments performed on fluorites derived from a spectrum of geological environments suggest a thermally activated volume diffusion mechanism. The diffusion behaviour is highly variable and the parameters range between log D0/a2 = 0.30 ± 0.27-7.27 ± 0.46 s-1 and Ea = 96 ± 3.5-182 ± 3.8 kJ/mol. Despite the fact that the CaF2 content of natural fluorites in most cases exceeds 99 weight percent, the closure temperature (Tc) of the fluorite (U-Th-Sm)/He thermochronometer as calculated from these diffusion parameters varies between 46 ± 14 °C and 169 ± 9 °C, considering a 125 μm fragment size. Here we establish that minor substitutions of calcium by rare earth elements and yttrium (REE + Y) and related charge compensation by sodium, fluorine, oxygen and/or vacancies in the fluorite crystal lattice have a significant impact on the diffusivity of helium in the mineral. With increasing REE + Y concentrations F vacancies are reduced and key diffusion pathways are narrowed. Consequently, a higher closure temperature is to be expected. An empirical case study confirms this variability: two fluorite samples from the same deposit (Horni Krupka, Czech Republic) with ca. 170 °C and ca. 43 °C Tc yield highly different (U-Th-Sm)/He ages of 290 ± 10 Ma and 79 ± 10 Ma, respectively. Accordingly, the fluorite sample with the high Tc could have quantitatively retained helium since the formation of the fluorite-bearing ores in the Permian, despite subsequent Mesozoic burial and associated regional hydrothermal heating. In contrast, the fluorite with the low Tc yields a Late Cretaceous age close to the apatite fission track (AFT) and apatite (U-Th)/He ages (AHe

  1. Fano Resonances observed in Helium Nanodroplets

    CERN Document Server

    LaForge, A C; Jabbari, G; Gokhberg, K; Kryzhevoi, N V; Krishnan, S R; Hess, M; O'Kee?e, P; Ciavardini, A; Prince, K C; Richter, R; Moshammer, R; Cederbaum, L S; Pfeifer, T; Stienkemeier, F; Mudrich, M

    2015-01-01

    Doubly-excited Rydberg states of helium (He) nanodroplets have been studied using synchrotron radiation. We observed Fano resonances related to the atomic N = 2,0 series as a function of droplet size. Although similar qualitatively to their atomic counterparts, the resonance lines are broader and exhibit a shift in energy which increases for the higher excited states. Furthermore, additional resonances are observed which are not seen in atomic systems. We discuss these features in terms of delocalized atomic states perturbed by the surrounding He atoms and compare to singly excited droplets.

  2. Heat capacity of helium in cylindrical environments

    Science.gov (United States)

    Gatica, S. M.; Hernández, E. S.; Szybisz, L.

    2003-10-01

    We perform a systematic investigation of the structure, elementary, and phonon excitations of quantum fluid 4He adsorbed in the interior of carbon nanotubes. We show that the helium fluid inside the cylinder behaves exactly as in planar films on a graphite substrate, presenting the same kind of layering transition. This tendency is confirmed by the behavior of a single 3He impurity diluted into adsorbed 4He. We also present a simple description of the lowest excitation modes of the adsorbed fluid and compute the low-temperature contribution of the phonon spectrum to the specific heat, which displays the dimensionality characteristics reported in previous works.

  3. Lamb shift in muonic helium ion

    CERN Document Server

    Martynenko, A P

    2006-01-01

    The Lamb shift (2P_{1/2}-2S_{1/2}) in the muonic helium ion (mu ^4_2He)^+ is calculated with the account of contributions of orders alpha^3, alpha^4, alpha^5 and alpha^6. Special attention is given to corrections of the electron vacuum polarization, the nuclear structure and recoil effects. The obtained numerical value of the Lamb shift 1381.716 meV can be considered as a reliable estimate for the comparison with experimental data.

  4. Influence of Helium in Gravitational Instabilities

    Science.gov (United States)

    Corona-Galindo, M. G.; Cardona, O.; Klapp, J.

    1990-11-01

    RESUMEN. Hemos analizado los modos hid rod inamicos de un modelo de fluido de dos componentes (hidr6geno y helio), y hemos obtenido la condici6n de inestabilidad para masas mayores que 1.39 veces la bien conocida masa dejeans. ABSTRACT, We have analysed the hydrodynamical modes of a two component fluid model (hydrogen and helium), and we have obtained the instability condition for masses greater than 1.39 times the well-known Jeans mass. K words: COSMOLOGY - GRAVITATION - INSTABILITIES

  5. Regulation and market power in the Spanish liquefied petroleum gas industry: Progress or failure?

    Energy Technology Data Exchange (ETDEWEB)

    Bello, Alejandro; Huerta, Emilio [Departamento de Gestion de Empresas, Universidad Publica de Navarra, Campus de Arrosadia, 31006 Pamplona, Navarra (Spain)

    2007-07-15

    This paper presents a detailed study of the structure, market power and competition in the distribution sector for liquefied petroleum gas (LPG), within Spain. It is a segment of energy consumption and supply that is not often given serious attention, despite the fact that LPG is a crucial source of energy to many households, in many countries in Europe and in the rest of the world. Despite formally being an open and liberalized sector, the Spanish LPG market is characterized by high concentration within the industry; Repsol Butano, the dominant operator, practically controls the entire value chain. These structural characteristics probably justify state intervention in the form of price fixing, in order to guarantee accessible prices for final consumers. Nevertheless, applying this tool has had negative effects on the opening and liberalization process. On the one hand, it fails to encourage entry or an increase in the participation of new operators; on the other, it has considerably deteriorated the economic and financial performance of the distribution agents that are subjected to two strong forces. First, the dominant operator looks after its own interests and its income; and second, the Government tries to defend the interests of final consumers by fixing prices that inadequately remunerate the activity. This shows the contradictory regulatory actions that try to promote competition, and then establish mechanisms to regulate activity by fixing prices that act as price limits. These government set prices discourage new competitors from entering. (author)

  6. Calculation models for prediction of Liquefied Natural Gas (LNG) ageing during ship transportation

    Energy Technology Data Exchange (ETDEWEB)

    Miana, Mario; Hoyo, Rafael del; Rodrigalvarez, Vega; Valdes, Jose Ramon [Instituto Tecnologico de Aragon, Area de Investigacion, Desarrollo y Servicios Tecnologicos, Maria de Luna 7, 50018 Zaragoza (Spain); Llorens, Raul [ENAGAS SA, Direccion de Ingenieria y Tecnologia del Gas, Autovia A - 2, km. 306.4, 50012 Zaragoza (Spain)

    2010-05-15

    A group of European gas transportation companies within the European Gas Research Group launched in 2007 the 'MOLAS' Project to provide a software program for the analysis of the Liquefied Natural Gas (LNG) ageing process during ship transportation. This program contains two different modeling approaches: a physical algorithm and an 'intelligent' model. Both models are fed with the same input data, which is composed of the ship characteristics (BOR and capacity), voyage duration, LNG composition, temperature, pressure, and volume occupied by liquid phase at the port of origin, together with pressure at the port of destination. The results obtained are the LNG composition, temperature and liquid volume at the port of destination. Furthermore, the physical model obtains the evolution over time of such variables en route as it is based on unsteady mass balances over the system, while the i-model applies neural networks to obtain regression coefficients from historical data composed only of origin and destination measurements. This paper describes both models and validates them from previous published models and experimental data measured in ENAGAS LNG regasification plants. (author)

  7. Compressed natural gas and liquefied petroleum gas conversions: The National Renewable Energy Laboratory`s experience

    Energy Technology Data Exchange (ETDEWEB)

    Motta, R.C.; Kelly, K.J.; Warnock, W.W.

    1996-04-01

    The National Renewable Energy Laboratory (NREL) contracted with conversion companies in six states to convert approximately 900 light-duty Federal fleet vehicles to operate on compressed natural gas (CNG) or liquefied petroleum gas (LPG). The contracts were initiated in order to help the Federal government meet the vehicle acquisition requirements of the Energy Policy Act of 1992 (EPACT) during a period of limited original equipment manufacturer (OEM) model availability. Approximately 90% of all conversions were performed on compact of full-size vans and pickups, and 90% of the conversions were to bi-fuel operation. With a positive response from the fleet managers, this program helped the Federal government meet the vehicle acquisition requirements of EPACT for fiscal years 1993 and 1994, despite limited OEM model availability. The conversions also helped to establish the infrastructure needed to support further growth in the use of alternative fuel vehicles. In conclusion, the program has been successful in helping the Federal government meet the vehicle acquisition requirements of EPACT, establishing infrastructure, increasing the displacement of imported oil, and evaluating the emissions performance of converted vehicles. With the relatively widespread availability of OEM vehicles in the 1996 model year, the program is now being phased out.

  8. Comparative investigation of diesel and mixed liquefied petroleum gas/diesel injection engines

    Energy Technology Data Exchange (ETDEWEB)

    Cao, J.; Bian, Y.; Qi, D.; Cheng, Q.; Wu, T. [Changan University, Xian (China). Automobile Faculty

    2004-05-01

    Experiments are conducted on engine performance and sprays and a characteristics analysis is made between diesel and mixed liquefied petroleum gas (LPG)/diesel injection engines. The performance test results show that with LPG the mixed ratio increases, engine power reduces slightly, fuel consumption and engine noise have almost no change, pollutant emissions of smoke, CO and NO{sub x} at full load are improved significantly, but the amount of unburned HC increases. The experimental results of the sprays indicate that because of flash boiling injection of mixed fuel, mean diameters in a spray decrease, the number distribution curve of fuel droplet size moves towards smaller diameters, small-size droplet numbers increase, spray quality is good and engine smoke reduces accordingly. Because large-size droplet diameters show almost no change and small-size droplet diameters decrease, the relative span factor and dispersion boundary factor of the droplet diameter increase. High-resolution digital camera photography is invaluable when carrying out a comparative investigation of spray. (author)

  9. Effect of liquefied petroleum gas on ozone formation in Guadalajara and Mexico City.

    Science.gov (United States)

    Jaimes-López, J Luis; Sandoval-Fernández, Julio; González-Ortíz, Emmanuel; Vázquez-García, Marcos; González-Macías, Uriel; Zambrano-García, Angel

    2005-06-01

    Leakages of liquefied petroleum gas (LPG) are suspected to contribute greatly to ozone (O3) formation in Mexico City. We tested such a hypothesis by outdoor captive-air irradiation (CAI) experiments in the two largest Mexican metropolitan areas: Guadalajara (GMA) in 1997 and Mexico City (MCMA) in 2000. O3 was monitored in each city for 20 days (8:00 a.m.-6:00 p.m.) in smog chambers containing unaltered morning air or morning air enriched with either commercial LPG or LPG synthetic mixture 60/40 (propane and butane). Tested additions of both components were 35% (by volume) in GMA and 60% (by volume) in MCMA. The addition effects on O3 (max) were compared with effects from diluting LPG components or total nonmethane hydrocarbons (tNMHCs) by 50%. Diluting tNMHCs had the greatest absolute effect at both cities: it lowered O3 (max) by 24% in GMA and 55% in MCMA. Adding commercial LPG increased O3 (max) by 6% in GMA and 28% in MCMA; whereas adding LPG synthetic mixture 60/40 caused a similar increase in O3 (max), 4 and 21% in GMA and MCMA, respectively. Compared with dilution of tNMHCs, dilution of LPG-associated compounds had a smaller decreasing effect on O3 (max), only 4% in GMA and 15% in MCMA. These results show that commercial LPG and LPG synthetic mixture 60/40 affect O3 formation to a lesser extent than estimated previously.

  10. The Effect of Polymer-Cement Stabilization on the Unconfined Compressive Strength of Liquefiable Soils

    Directory of Open Access Journals (Sweden)

    Ali Ateş

    2013-01-01

    Full Text Available Soil stabilization has been widely used as an alternative to substitute the lack of suitable material on site. The use of nontraditional chemical stabilizers in soil improvement is growing daily. In this study a laboratory experiment was conducted to evaluate the effects of waterborne polymer on unconfined compression strength and to study the effect of cement grout on pre-venting of liquefiable sandy soils. The laboratory tests were performed including grain size of sandy soil, unit weight, ultrasonic pulse velocity, and unconfined compressive strength test. The sand and various amounts of polymer (1%, 2%, 3%, and 4% and cement (10%, 20%, 30%, and 40% were mixed with all of them into dough using mechanical kneader in laboratory conditions. Grouting experiment is performed with a cylindrical mould of  mm. The samples were subjected to unconfined compression tests to determine their strength after 7 and 14 days of curing. The results of the tests indicated that the waterborne polymer significantly improved the unconfined compression strength of sandy soils which have susceptibility of liquefaction.

  11. Blanketing effect of expansion foam on liquefied natural gas (LNG) spillage pool.

    Science.gov (United States)

    Zhang, Bin; Liu, Yi; Olewski, Tomasz; Vechot, Luc; Mannan, M Sam

    2014-09-15

    With increasing consumption of natural gas, the safety of liquefied natural gas (LNG) utilization has become an issue that requires a comprehensive study on the risk of LNG spillage in facilities with mitigation measures. The immediate hazard associated with an LNG spill is the vapor hazard, i.e., a flammable vapor cloud at the ground level, due to rapid vaporization and dense gas behavior. It was believed that high expansion foam mitigated LNG vapor hazard through warming effect (raising vapor buoyancy), but the boil-off effect increased vaporization rate due to the heat from water drainage of foam. This work reveals the existence of blocking effect (blocking convection and radiation to the pool) to reduce vaporization rate. The blanketing effect on source term (vaporization rate) is a combination of boil-off and blocking effect, which was quantitatively studied through seven tests conducted in a wind tunnel with liquid nitrogen. Since the blocking effect reduces more heat to the pool than the boil-off effect adds, the blanketing effect contributes to the net reduction of heat convection and radiation to the pool by 70%. Water drainage rate of high expansion foam is essential to determine the effectiveness of blanketing effect, since water provides the boil-off effect.

  12. Distribution and Chain Pattern of Liquefied Natural Gas Industry in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The production and consumption of natural gas in China has been developing rapidly in recent years. It is expected that the annual growth rate of the demand for natural gas will reach 12% in the next 15 years, and the gas consumption in the primary energy will increase from 0.3% to 10% or more by 2020. However, since the supply of natural gas cannot satisfy the requirements, China has begun to build liquefied natural gas (LNG) terminals in the coastal regions such as Guangdong and Fujian, and solve this problem by importing LNG from foreign countries. LNG needs to be transported by LNG ships from abroad. With the rapid growth of global gas production, the volume of LNG trade also increases, and the interregional production increased from 0.3% in 1970 to 26.2% in 2004. So, we need LNG ships more than before. This article puts forward the distribution of LNG ships and the speculation of the future of LNG transportation based on the studies on foreign LNG production, the LNG trade, the building of LNG ships, the LNG transportation, the chain model of LNG distribution, etc.

  13. Life-cycle greenhouse gas assessment of Nigerian liquefied natural gas addressing uncertainty.

    Science.gov (United States)

    Safaei, Amir; Freire, Fausto; Henggeler Antunes, Carlos

    2015-03-17

    Natural gas (NG) has been regarded as a bridge fuel toward renewable sources and is expected to play a greater role in future global energy mix; however, a high degree of uncertainty exists concerning upstream (well-to-tank, WtT) greenhouse gas (GHG) emissions of NG. In this study, a life-cycle (LC) model is built to assess uncertainty in WtT GHG emissions of liquefied NG (LNG) supplied to Europe by Nigeria. The 90% prediction interval of GHG intensity of Nigerian LNG was found to range between 14.9 and 19.3 g CO2 eq/MJ, with a mean value of 16.8 g CO2 eq/MJ. This intensity was estimated considering no venting practice in Nigerian fields. The mean estimation can shift up to 25 g CO2 eq when considering a scenario with a higher rate of venting emissions. A sensitivity analysis of the time horizon to calculate GHG intensity was also performed showing that higher GHG intensity and uncertainty are obtained for shorter time horizons, due to the higher impact factor of methane. The uncertainty calculated for Nigerian LNG, specifically regarding the gap of data for methane emissions, recommends initiatives to measure and report emissions and further LC studies to identify hotspots to reduce the GHG intensity of LNG chains.

  14. ANALISIS INVESTASI PROYEK PEMBANGUNAN TERMINAL LIQUEFIED NATURAL GAS (LNG DI LABUAN MARINGGAI BERDASARKAN ANALISA BEBAN MODAL

    Directory of Open Access Journals (Sweden)

    Lebinner Sinaga

    2015-02-01

    Full Text Available Meningkatnya kebutuhan akan energi gas bumi tidak terlepas dari kondisi makro ekonomi di Indonesia. Dampak yang paling besar adalah dengan semakin berkembangnya sektor industri dalam negeri terutama di wilayah Jawa Barat dan Lampung, maka kebutuhan gas di wilayah ini meningkat untuk masa mendatang.Kondisi ini oleh PGN harus disikapi dengan serius dikarenakan kemampuan supply untuk gas saat ini tidak bisa untuk memenuhi kenaikan gas di masa mendatang yaitu sekitar 44% kenaikan kebutuhan gas. Saat ini PGN untuk wilayah Jawa Barat dan Lampung hanya mampu untuk mensupply sekitar 590 MMscfd, dengan target PGN untuk sepuluh tahun mendatang yaitu 1000 MMscfd, maka terjadi defisit supply gas sekitar 410 MMscfd. Dalam mencapai target supply gas yang telah ditetapkan yaitu 1000 Mmscfd dikarenakan terbatasnya pasokan gas dari sumber gas, maka PGN akan melakukan terobosan baru dengan keluar dari konsep supplay gas konvesional yakni dengan menggunakan gas alam cair atau Liquefied Natural Gas  (LNG. Dengan konsep ini, maka pasokan gas menjadi tidak terbatas, karena dapat didatangkan dari berbagai tempat ataupun dari negara lain. Dalam mendatangkan gas alam cair ini, dibutuhkan suatu stasiun penerima gas yang biasa disebut LNG Receiving yang penempatannya dengan berbagai pertimbangan dipilih di darat (onshore. Pembangunan terminal LNG ini sangat dibutuhkan untuk meningkatkan supply gas PGN. Pembangunan terminal LNG ini diperlukan satu arahan secara economical value. Dengan menggunakan metode Nilai Sekarang Bersih (NSB, Nilai Tahunan Bersih (NTB, dan Tingkat Pengembalian Internal (IRR maka proyek Pembangunan Terminal LNG ini layak untuk dilaksanakan.

  15. VidaGas : powering health clinics and households in Mozambique with liquefied petroleum gas

    Energy Technology Data Exchange (ETDEWEB)

    Sprague, C. [Witwatersand Univ. (South Africa). Graduate School of Business Administration; Woolman, S. [Pretoria Univ., Pretoria (South Africa)

    2008-07-01

    This paper described a pro-poor venture established to provide a sustainable supply of liquefied petroleum gas (LPG) in northern Mozambique. The venture is needed in order to become a venue-generating entity within 3 years. Challenges to the success of the VidaGas project include insufficient LPG supply and storage facilities, and a lack of commercial and industrial infrastructure. Retailers and consumers in the region have little experience in dealing with LPG. Most households and medical practices in the region rely on wood or charcoal for cooking. The deforestation of local mangroves is now imperilling the region's commercial fishing industry. To date, the venture has replaced kerosene refrigerators in health facilities with LPG refrigerators. Staff have also been trained to deliver LPG and lamps to healthcare workers on a regular basis. The healthcare initiative has increased interest in the use of LPG in the region, and the VidaGas project now involves several large commercial and industrial consumers. LPG emits fewer greenhouse gases (GHGs) than many other fuels, and is highly portable. The LPG in Mozambique is supplied by South Africa. It was concluded that VidaGas is now achieving financial sustainability in the region. 24 refs., 2 figs.

  16. Activities to support the liquefied gaseous fuels spill test facility program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sheesley, D.; King, S.B.; Routh, T.

    1997-03-01

    Approximately a hundred years ago the petrochemical industry was in its infancy, while the chemical industry was already well established. Today, both of these industries, which are almost indistinguishable, are a substantial part of the makeup of the U.S. economy and the lifestyle we enjoy. It is difficult to identify a single segment of our daily lives that isn`t affected by these industries and the products or services they make available for our use. Their survival and continued function in a competitive world market are necessary to maintain our current standard of living. The occurrence of accidents in these industries has two obvious effects: (1) the loss of product during the accident and future productivity because of loss of a portion of a facility or transport medium, and (2) the potential loss of life or injury to individuals, whether workers, emergency responders, or members of the general public. A great deal of work has been conducted at the Liquefied Gaseous Fuels Spill test Facility (LGFSTF) on hazardous spills. WRI has conducted accident investigations as well as provided information on the research results via the internet and bibliographies.

  17. Cooperation among liquefied natural gas suppliers. Is rationalization the sole objective?

    Energy Technology Data Exchange (ETDEWEB)

    Massol, Olivier [Center for Economics and Management, IFP School, 228-232 av. Napoleon Bonaparte, F-92852 Rueil-Malmaison (France); Department of Economics, City University, Northampton Square, London EC1V 0HB (United Kingdom); Tchung-Ming, Stephane [Economic Studies Division, IFP, 1-4 av. de Bois-Preau, F-92852 Rueil Malmaison (France); CREDEN, Universite Montpellier I, Av. de la mer, BP 9606, F-34054, Montpellier (France)

    2010-07-15

    This paper examines the development of cooperative strategies between countries exporting Liquefied Natural Gas (LNG) and members of the Gas Exporting Countries Forum (GECF). This economic study focuses specifically on an often-raised scenario: the emergence of a cooperative approach designed with the sole aim of logistic rationalization, and which would not have any effect on LNG prices. We first assess the annual gains that may result from this market-power-free cooperative approach using a simple static transportation model. The numerical results obtained suggest that, in the absence of a gain redistribution policy, this cooperative strategy will probably not be adopted because cooperation would not be a rational move for some exporters. The problem of gain sharing is then formulated using cooperative game theory concepts. Several gain-sharing methods have been studied, including the Shapley value and various nucleolus-inspired concepts. Our results suggest that the choice of a redistribution policy appears relatively restricted. Out of the methods studied, only one - per capita nucleolus - satisfies two key requirements. core belonging and monotonicity (in the aggregate). Lastly, we look at how cooperation may give rise to a coordination cost and try to determine the maximum amount of this cost. In view of the low level of this amount and the relative complexity of the sharing method implemented, we consider that the credibility of a logistic cooperation scenario exempt from market power should be reappraised. (author)

  18. The risks of Bobtail truck LPG (Liquefied Petroleum Gases) distribution in urban areas

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Cesar A. [Det Norske Veritas (DNV), Oslo (Norway)], e-mail: cesar.leal@dnv.com

    2008-07-01

    The use of 'Bobtail' trucks (6 and 9 ton) for distribution of Liquefied Petroleum Gas (LPG) in Brazilian cities represents a new and mobile source of risk. In this paper, it will be presented a discussion about some of the possible accident scenarios that can occur with this kind of vehicle, with emphasis on the possible consequences (BLEVE/fireball). The goal is to spread information and call attention of Government Authorities and gas distribution companies, as well as the general public, about this source of risk. In the case of a 9 ton fireball, fatalities could be expected up to 176 m, according to TNO models. Collapse of the tank engulfed in fire is expected in 10 to 20 minutes, a too short time interval for the arrival of a fire brigade and control of the situation. Suggestions are presented for the use of insulating coating in the tanks capable of withstanding an external fire for two hours without collapsing and the realization of a risk study for estimation of the impact of the use of insulation in terms of risk reduction for the population and a comparison of risks associated to the two forms of LPG distribution. (author)

  19. Supernovae from direct collisions of white dwarfs and the role of helium shell ignition

    CERN Document Server

    Papish, Oded

    2015-01-01

    Models for supernovae (SNe) arising from thermonuclear explosions of white dwarfs (WDs) have been extensively studied over the last few decades, mostly focusing on the single degenerate (accretion of material of a WD) and double degenerate (WD-WD merger) scenarios. In recent years it was suggested that WD-WD direct collisions provide an additional channel for such explosions. Here we extend the studies of such explosions, and explore the role of Helium-shells in affecting the thermonuclear explosions. We study both the impact of low-mass helium ($\\sim0.01$ M$_{\\odot})$ shells, as well as high mass shells ($\\ge0.1$ M$_{\\odot}$). We find that detonation of the massive helium layers precede the detonation of the WD Carbon-Oxygen (CO) bulk during the collision and can change the explosive evolution and outcomes for the cases of high mass He-shells. In particular, the He-shell detonation propagates on the WD surface and inefficiently burns material prior to the CO detonation that later follows in the central parts...

  20. Thermal Desorption of Helium Implanted in Tungsten at RT

    Institute of Scientific and Technical Information of China (English)

    ZHANGFu; XUZengyu; LIUXiang; CHENJiming; XUYing; N.Yoshida; H.Iwakiri

    2002-01-01

    Tungsten is envisaged as one of the main candidate materials for divertor plate of ITER and future fusion reactors. Due to D-T reaction, PFMs would suffer helium irradiation from plasma additional to the high heat loads. Helium retention and thermal desorption behavior are largely concerned.

  1. Deposition, milling, and etching with a focused helium ion beam

    NARCIS (Netherlands)

    Alkemade, P.F.A.; Veldhoven, E. van

    2012-01-01

    The recent successful development of the helium ion microscope has produced both a new type of microscopy and a new tool for nanoscale manufacturing. This chapter reviews the first explorations in this new field in nanofabrication. The studies that utilize the Orion helium ion microscope to grow or

  2. Helium on Venus - Implications for uranium and thorium

    Science.gov (United States)

    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.

  3. The Orsay polarized electron source from a flowing helium afterglow

    Science.gov (United States)

    Arianer, J.; Brissaud, I.; Essabaa, S.; Humblot, H.; Zerhouni, W.

    1993-12-01

    A polarized electron source was designed at Orsay. We have chosen to adapt the flowing helium afterglow source working at Rice University because it provides a very high polarization. We have investigated a new way for the optical pumping of the helium metastables. An 85% electron polarization was reached.

  4. Submersion of potassium clusters in helium nanodroplets

    Science.gov (United States)

    An der Lan, Lukas; Bartl, Peter; Leidlmair, Christian; Schöbel, Harald; Denifl, Stephan; Märk, Tilmann D.; Ellis, Andrew M.; Scheier, Paul

    2012-03-01

    Small alkali clusters do not submerge in liquid helium nanodroplets but instead survive predominantly in high spin states that reside on the surface of the nanodroplet. However, a recent theoretical prediction by Stark and Kresin [Phys. Rev. BPLRBAQ1098-012110.1103/PhysRevB.81.085401 81, 085401 (2010)], based on a classical description of the energetics of bubble formation for a fully submerged alkali cluster, suggests that the alkali clusters can submerge on energetic grounds when they exceed a critical size. Following recent work on sodium clusters, where ion yield data from electron impact mass spectrometry was used to obtain the first experimental evidence for alkali cluster submersion, we report here on similar experiments for potassium clusters. Evidence is presented for full cluster submersion at n>80 for Kn clusters, which is in good agreement with the recent theoretical prediction. In an additional observation, we report “magic number” sizes for both Kn+ and Kn2+ ions derived from helium droplets, which are found to be consistent with the jellium model.

  5. Neutrons on a surface of liquid helium

    Science.gov (United States)

    Grigoriev, P. D.; Zimmer, O.; Grigoriev, A. D.; Ziman, T.

    2016-08-01

    We investigate the possibility of ultracold neutron (UCN) storage in quantum states defined by the combined potentials of the Earth's gravity and the neutron optical repulsion by a horizontal surface of liquid helium. We analyze the stability of the lowest quantum state, which is most susceptible to perturbations due to surface excitations, against scattering by helium atoms in the vapor and by excitations of the liquid, comprised of ripplons, phonons, and surfons. This is an unusual scattering problem since the kinetic energy of the neutron parallel to the surface may be much greater than the binding energies perpendicular. The total scattering time of these UCNs at 0.7 K is found to exceed 1 h, and rapidly increases with decreasing temperature. Such low scattering rates should enable high-precision measurements of the sequence of discrete energy levels, thus providing improved tests of short-range gravity. The system might also be useful for neutron β -decay experiments. We also sketch new experimental propositions for level population and trapping of ultracold neutrons above a flat horizontal mirror.

  6. Mining for helium: Site selection and evaluation

    Science.gov (United States)

    Cameron, Eugene N.

    1988-09-01

    Part of the University of Wisconsin study of the feasibility of recovering He-3 from the moon is selection and evaluation of potential mining sites. Selection and evaluation are based primarily on salient findings by investigators: (1) Regoliths from areas underlain by highland materials contain less than 20 wppm He; (2) Regoliths of certain maria or parts of maria also contain less than 20 wppm He, but mare regoliths at the Apollo 11 and 17 sites contain 25 to 49 wppm He; (3) The helium content of a regolith is a function of its composition; and (4) Helium is concentrated in the -50 micron size fractions of regoliths. In site selection, the concern is with the compositions of lunar regoliths, in particular with their titanium contents. It is widely accepted that compositions of mare regoliths are controlled by the nature of the underlying basalts from which the regoliths are largely derived. The distribution and extent of the three groups of basalts and the regoliths derived from them are the first basis for site selection and evaluation. Other considerations are briefly discussed.

  7. Liquid uranium alloy-helium fission reactor

    Science.gov (United States)

    Minkov, V.

    1984-06-13

    This invention describes a nuclear fission reactor which has a core vessel and at least one tandem heat exchanger vessel coupled therewith across upper and lower passages to define a closed flow loop. Nuclear fuel such as a uranium alloy in its liquid phase fills these vessels and flow passages. Solid control elements in the reactor core vessel are adapted to be adjusted relative to one another to control fission reaction of the liquid fuel therein. Moderator elements in the other vessel and flow passages preclude fission reaction therein. An inert gas such as helium is bubbled upwardly through the heat exchanger vessel operable to move the liquid fuel upwardly therein and unidirectionally around the closed loop and downwardly through the core vessel. This helium gas is further directed to heat conversion means outside of the reactor vessels to utilize the heat from the fission reaction to generate useful output. The nuclear fuel operates in the 1200 to 1800/sup 0/C range, and even higher to 2500/sup 0/C.

  8. Neutrons on a surface of liquid helium

    CERN Document Server

    Grigoriev, P D; Ziman, T; Grigoriev, A D

    2015-01-01

    We investigate the possibility of ultracold neutron (UCN) storage in quantum states defined by the combined potentials of the Earth's gravity and the neutron optical repulsion by a horizontal surface of liquid helium. We analyse the stability of the lowest quantum state, which is most susceptible to perturbations due to surface excitations, against scattering by helium atoms in the vapor and by excitations of the liquid, comprised of ripplons, phonons and surfons. This is an unusual scattering problem since the kinetic energy of the neutron parallel to the surface may be much greater than the binding energies perpendicular. The total scattering time constant of these UCNs at 0.7 K is found to exceed one hour, and rapidly increasing with decreasing temperature. Such low scattering rates should enable high-precision measurements of the scheme of discrete energy levels, thus providing improved access to short-range gravity. The system might also be useful for neutron beta-decay experiments. We also sketch new ex...

  9. High-precision spectroscopy of antiprotonic helium

    CERN Document Server

    Widmann, E

    2001-01-01

    We present first results of laser and microwave spectroscopy experiments of antiprotonic helium performed at the new Antiproton Decelerator (AD) at CERN. Extending a series of previous measurements done at the Low Energy Antiproton Ring (LEAR) of CERN, several laser- induced transitions of the antiproton in the exotic three-body system He/sup 2+/-e/sup -/-p could be determined with a precision down to 1.3*10/sup -7/. This constitutes an improvement of a factor 3 over previous measurements, and allows to test accurate three-body calculations of this system that include QED corrections. The observed agreement on the same level can be used to infer CPT limits on the antiproton charge and mass. Furthermore, a first indication of a resonance signal of a two-laser microwave triple experiment to measure the hyperfine splitting of antiprotonic helium could been observed. Such a measurement has the potential to determine the antiproton magnetic moment to a higher precision that it is known today. (19 refs).

  10. Localized helium excitations in 4He_N-benzene clusters

    CERN Document Server

    Huang, P; Huang, Patrick

    2003-01-01

    We compute ground and excited state properties of small helium clusters 4He_N containing a single benzene impurity molecule. Ground-state structures and energies are obtained for N=1,2,3,14 from importance-sampled, rigid-body diffusion Monte Carlo (DMC). Excited state energies due to helium vibrational motion near the molecule surface are evaluated using the projection operator, imaginary time spectral evolution (POITSE) method. We find excitation energies of up to ~23 K above the ground state. These states all possess vibrational character of helium atoms in a highly anisotropic potential due to the aromatic molecule, and can be categorized in terms of localized and collective vibrational modes. These results appear to provide precursors for a transition from localized to collective helium excitations at molecular nanosubstrates of increasing size. We discuss the implications of these results for analysis of anomalous spectral features in recent spectroscopic studies of large aromatic molecules in helium clu...

  11. Helium Burning Reaction Rate Uncertainties and Consequences for Supernovae

    Science.gov (United States)

    Tur, C.; Heger, A.; Austin, S. M.

    2007-10-01

    The triple alpha and ^12C(,)^16O reaction rates determine the carbon to oxygen ratio at the completion of core helium burning in stars, which, in turn, influences the later stellar burning stages. We explored the dependence of massive star evolution and nucleosynthesis yields on the experimental uncertainties in the triple alpha rate (10 to 12%) and the ^12C(,)^16O rate (25 to 35%) using full stellar models followed to core collapse and including supernova explosion. The production factors of medium-weight elements obtained by using the Lodders (2003) solar abundances for the initial star composition, rather than the abundances of Anders & Grevesse (1989), provide a less stringent constraint on the ^12C(,)^16O rate. Variations within the current uncertainties in both reaction rates, however, induce significant changes in the central carbon abundance at core carbon ignition and in the mass of the supernova remnant. An experiment is being carried out by an NSCL/WMU collaboration to improve the accuracy of the triple alpha reaction rate.

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

    Science.gov (United States)

    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…

  13. Helium-Charged Titanium Films Deposited by Pulsed Laser Deposition in an Electron-Cyclotron-Resonance Helium Plasma Environment

    Institute of Scientific and Technical Information of China (English)

    金钦华; 胡佩钢; 凌浩; 吴嘉达; 施立群; 周筑颖

    2003-01-01

    Titanium thin films incorporated with helium are produced by pulsed laser deposition in an electron cyclotron resonance helium plasma environment. Helium is distributed evenly in the film and a relatively high He/Ti atomic ratio (~ 20%) is obtained from the proton backscattering spectroscopy. This high concentration ofhelium leads to a surface blistering which is observed by scanning electron microscopy. Laser repetition rate has little influence on film characters. Substrate bias voltage is also changed for the helium incorporating mechanism study, and this is a helium ion implantation process during the film growth. Choosing suitable substrate bias voltage, one can avoid the damage produced by ion implantation, which is always present in general implantation case.

  14. Application of computational chemistry methods to obtain thermodynamic data for hydrogen production from liquefied petroleum gas

    Directory of Open Access Journals (Sweden)

    J. A. Sousa

    2013-03-01

    Full Text Available The objective of this study was to estimate thermodynamic data, such as standard enthalpy, entropy and Gibbs free energy changes of reaction and, consequently, chemical equilibrium constants, for a reaction system describing the hydrogen production from Liquefied Petroleum Gas (LPG. The acquisition of those properties was made using computational chemistry methods and the results were compared with experimental data reported in the literature. The reaction system of steam reforming of LPG was reported as a set of seven independent reactions involving the chemical species n-C4H10, C3H8, C2H6, C2H4, CH4, CO2, CO, H2O, H2 and solid carbon. Six computational approaches were used: Density Functional Theory (DFT employing Becke's three parameter hybrid exchange functional, and the Lee-Yang-Parr correlation functional (B3LYP using the 6-31G++(d,p basis set and the composite methods CBS-QB3, Gaussian-1 (G1, Gaussian-2 (G2, Gaussian-3 (G3 and Gaussian-4 (G4. Mole fractions of the system components were also determined between 873.15 and 1173.15 K, at 1 atm and a feed with a stoichiometric amount of water. Results showed that the hybrid functional B3LYP/6-31G++(d,p, G3 and G4 theories were the most appropriated methods to predict the properties of interest. Gaussian-3 and Gaussian-4 theories are expected to be good thermodynamic data predictors and the known efficient prediction of vibrational frequencies by B3LYP is probably the source of the good agreement found in this study. This last methodology is of special interest since it presents low computational cost, which is important when more complex molecular systems are considered.

  15. AIR QUALITY IMPACTS OF LIQUEFIED NATURAL GAS IN THE SOUTH COAST AIR BASIN OF CALIFORNIA

    Energy Technology Data Exchange (ETDEWEB)

    Carerras-Sospedra, Marc; Brouwer, Jack; Dabdub, Donald; Lunden, Melissa; Singer, Brett

    2011-07-01

    The effects of liquefied natural gas (LNG) on pollutant emission inventories and air quality in the South Coast Air Basin of California were evaluated using recent LNG emission measurements by Lawrence Berkeley National Laboratory and the Southern California Gas Company (SoCalGas), and with a state-of-the-art air quality model. Pollutant emissions can be affected by LNG owing to differences in composition and physical properties, including the Wobbe index, a measure of energy delivery rate. This analysis uses LNG distribution scenarios developed by modeling Southern California gas flows, including supplies from the LNG receiving terminal in Baja California, Mexico. Based on these scenarios, the projected penetratino of LNG in the South Coast Air Basin is expected to be limited. In addition, the increased Wobbe index of delivered gas (resulting from mixtures of LNG and conventional gas supplies) is expected to cause increases smaller than 0.05 percent in overall (area-wide) emissions of nitrogen oxides (NOx). BAsed on the photochemical state of the South Coast Air Basin, any increase in NOx is expected to cause an increase in the highest local ozone concentrations, and this is reflected in model results. However, the magnitude of the increase is well below the generally accepted accuracy of the model and would not be discernible with the existing monitoring network. Modeling of hypothetical scenarios indicates that discernible changes to ambient ozone and particulate matter concentrations would occur only at LNG distribution rates that are not achievable with current or planned infrastructure and with Wobbe index vlaues that exceed current gas quality tariffs. Results of these hypothetical scenarios are presented for consideration of any proposed substantial expansion of LNG supply infrastructure in Southern California.

  16. Ventilation of liquefied petroleum gas components from the Valley of Mexico

    Science.gov (United States)

    Elliott, Scott; Blake, Donald R.; Rowland, F. Sherwood; Lu, Rong; Brown, Michael J.; Williams, Michael D.; Russell, Armistead G.; Bossert, James E.; Streit, Gerald E.; Santoyo, Marisa Ruiz; Guzman, Francisco; Porch, William M.; McNair, Laurie A.; Keyantash, John; Kao, Chih-Yue Jim; Turco, Richard P.; Eichinger, William E.

    1997-09-01

    The saturated hydrocarbons propane and the butane isomers are both indirect greenhouse gases and key species in liquefied petroleum gas (LPG). Leakage of LPG and its component alkanes/alkenes is now thought to explain a significant fraction of the volatile organic burden and oxidative potential in the basin which confines Mexico City. Propane and the butanes, however, are stable enough to escape from the basin. The gas Chromatographie measurements which have drawn attention to their sources within the urban area are used here to estimate rates of ventilation into the free troposphere. The calculations are centered on several well studied February/March pollution episodes. Carbon monoxide observations and emissions data are first exploited to provide a rough time constant for the removal of typical inert pollutant species from the valley. The timescale obtained is validated through an examination of meteorological simulations of three-dimensional flow. Heuristic arguments and transport modeling establish that propane and the butanes are distributed through the basin in a manner analogous to CO despite differing emissions functions. Ventilation rates and mass loadings yield outbound fluxes in a box model type computation. Estimated in this fashion, escape from the Valley of Mexico constitutes of the order of half of 1% of the northern hemispheric inputs for both propane and n-butane. Uncertainties in the calculations are detailed and include factors such as flow into the basin via surface winds and the size of the polluted regime. General quantification of the global propane and butane emissions from large cities will entail studies of this type in a variety of locales.

  17. Economic and environmental assessment of liquefied natural gas as a supplemental aircraft fuel

    Science.gov (United States)

    Withers, Mitch R.; Malina, Robert; Gilmore, Christopher K.; Gibbs, Jonathan M.; Trigg, Chris; Wolfe, Philip J.; Trivedi, Parthsarathi; Barrett, Steven R. H.

    2014-04-01

    In 2013, natural gas is 70-80% cheaper than jet fuel on an energy basis. As an alternative aviation fuel, natural gas may reduce operating costs. In this paper, we assess the use of liquefied natural gas (LNG) as a supplemental aircraft fuel in a military context, with detailed assessments of the Lockheed Martin C-130H and C-130J transport aircraft. We estimate the cost of retrofitting these aircraft to use LNG and the savings from reduced fuel expenses. We evaluate the societal impacts of LNG within a cost-benefit framework, taking into account resource consumption, human health impacts related to air quality, and climate damage. In order to compare alternative uses of natural gas in aviation, we include in our analysis Fischer-Tropsch (FT) jet fuel from natural gas as a drop-in alternative. Uncertainty analysis is performed with Monte Carlo simulations. We find that aircraft operators can save up to 14% on fuel expenses (retrofit costs included) by employing LNG retrofits, with a 95% confidence interval of 2-23%. Society can also benefit by 12% (3-20%) from LNG use as a result of improved surface air quality, lower resource consumption, and net climate neutrality. These results are highly dependent on fuel prices, the quantity and cost of the LNG retrofits, and the frequency and length of missions. FT jet fuel is not cost-competitive with conventional fuel and results in increased fuel expenses by 17%. FT fuel provides marginal societal benefits relative to jet fuel.

  18. The impact of liquefied petroleum gas usage on air quality in Mexico City

    Science.gov (United States)

    Gasca, J.; Ortiz, E.; Castillo, H.; Jaimes, J. L.; González, U.

    Liquefied petroleum gas (LPG) is the main fuel used in the residential sector of the Metropolitan Zone in the Valley of Mexico (MZVM). LPG represents 16% of the total fuel consumption in the MZVM and its demand increased 14% from 1986 to 1999. Propane and butanes, the main compounds of LPG, constituted 29% of all non-methane hydrocarbons found in the air of Mexico City. Some researchers have reported that LPG losses are a significant cause of high ozone concentration in MZVM. Three analyses are carried out in this work to estimate LPG's share of responsibility for MZVM pollution problems. First, the correlation between LPG consumption and three ozone pollution indicators was calculated for the period of 1986-1999. The non-significant correlation of these indicators with LPG consumption in a monthly basis suggests that LPG associated emissions are not the foremost cause of ozone formation. Second, a simulation model is applied to three LPG related emission control strategies to estimate the reduction in the maximum ozone concentration. The most noticeable effect was obtained when both hydrocarbon (HC) and oxides of nitrogen (NO x) emissions associated with LPG use were totally reduced. The other two strategies, that only reduce HC emissions, had a minimum effect on the ozone concentration. Third, organic compounds consumption in air samples captured and irradiated in outdoor smog chambers is used to determine the chemical loss rate of LPG associated species and aromatics in the MZVM. The smog chamber results showed that 70% of propane and n-butane remain at the end of a 1-day irradiation, therefore they remain in the MZVM atmosphere for several days being the reason for the high concentration of these compounds. LPG associated compounds only account for 18% of ozone formed but aromatics contribute 35% to ozone in smog chamber.

  19. Ventilation of liquefied petroleum gas components from the Valley of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, S. [Earth and Environmental Science Division, Geoanalysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Blake, D.R.; Sherwood Rowland, F. [Chemistry Department, University of California, Irvine (United States); Lu, R. [Atmospheric Sciences Department, University of California, Los Angeles (United States); Brown, M.J.; Williams, M.D. [Technology and Safety Assessment Division, Energy and Environmental Analysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Russell, A.G. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania (United States); Bossert, J.E. [Earth and Environmental Science Division, Geoanalysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Streit, G.E. [Technology and Safety Assessment Division, Energy and Environmental Analysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Santoyo, M.R.; Guzman, F. [Instituto Mexicano del Petroleo, Gerencia de Ciencias del Ambiente, (Mexico) D.F.; Porch, W.M. [Earth and Environmental Science Division, Geoanalysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); McNair, L.A. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania (United States); Keyantash, J. [Atmospheric Sciences Department, University of California, Los Angeles (United States); Kao, C.J. [Earth and Environmental Science Division, Geoanalysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Turco, R.P. [Atmospheric Sciences Department, University of California, Los Angeles (United States); Eichinger, W.E. [Earth and Environmental Science Division, Geoanalysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

    1997-09-01

    The saturated hydrocarbons propane and the butane isomers are both indirect greenhouse gases and key species in liquefied petroleum gas (LPG). Leakage of LPG and its component alkanes/alkenes is now thought to explain a significant fraction of the volatile organic burden and oxidative potential in the basin which confines Mexico City. Propane and the butanes, however, are stable enough to escape from the basin. The gas chromatographic measurements which have drawn attention to their sources within the urban area are used here to estimate rates of ventilation into the free troposphere. The calculations are centered on several well studied February/March pollution episodes. Carbon monoxide observations and emissions data are first exploited to provide a rough time constant for the removal of typical inert pollutant species from the valley. The timescale obtained is validated through an examination of meteorological simulations of three-dimensional flow. Heuristic arguments and transport modeling establish that propane and the butanes are distributed through the basin in a manner analogous to CO despite differing emissions functions. Ventilation rates and mass loadings yield outbound fluxes in a box model type computation. Estimated in this fashion, escape from the Valley of Mexico constitutes of the order of half of 1{percent} of the northern hemispheric inputs for both propane and n-butane. Uncertainties in the calculations are detailed and include factors such as flow into the basin via surface winds and the size of the polluted regime. General quantification of the global propane and butane emissions from large cities will entail studies of this type in a variety of locales.{copyright} 1997 American Geophysical Union

  20. The impact of liquefied petroleum gas usage on air quality in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Gasca, J.; Ortiz, E.; Castillo, H.; Jaimes, J.L.; Gonzalez, U. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas, Mexico City (Mexico)

    2004-07-01

    Liquefied petroleum gas (LPG) is the main fuel used in the residential sector of the Metropolitan Zone in the Valley of Mexico (MZVM). LPG represents 16% of the total fuel consumption in the MZVM and its demand increased 14% from 1986 to 1999. Propane and butanes, the main compounds of LPG, constituted 29% of all non-methane hydrocarbons found in the air of Mexico City. Some researchers have reported that LPG losses are a significant cause of high ozone concentration in MZVM. Three analyses are carried out in this work to estimate LPG's share of responsibility for MZVM pollution problems. First, the correlation between LPG consumption and three ozone pollution indicators was calculated for the period of 1986-1999. The non-significant correlation of these indicators with LPG consumption on a monthly basis suggests that LPG associated emissions are not the foremost cause of ozone formation. Second, a simulation model is applied to three LPG related emission control strategies to estimate the reduction in the maximum ozone concentration. The most noticeable effect was obtained when both hydrocarbon (HC) and oxides of nitrogen (NO{sub x}) emissions associated with LPG use were totally reduced. The other two strategies, that only reduce HC emissions, had a minimum effect on the ozone concentration. Third, organic compounds consumption in air samples captured and irradiated in outdoor smog chambers is used to determine the chemical loss rate of LPG associated species and aromatics in the MZVM. The smog chamber results showed that 70% of propane and n-butane remain at the end of a 1-day irradiation, therefore they remain in the MZVM atmosphere for several days being the reason for the high concentration of these compounds. LPG associated compounds only account for 18% of ozone formed but aromatics contribute 35% to ozone in smog chamber. (Author)

  1. Experimental and numerical investigation of the roll motion behavior of a floating liquefied natural gas system

    Science.gov (United States)

    Zhao, WenHua; Yang, JianMin; Hu, ZhiQiang; Xiao, LongFei; Peng, Tao

    2013-03-01

    The present paper does an experimental and numerical investigation of the hydrodynamic interaction and the response of a single point turret-moored Floating Liquefied Natural Gas (FLNG) system, which is a new type of floating LNG (Liquid Natural Gas) platform that consists of a ship-type FPSO hull equipped with LNG storage tanks and liquefaction plants. In particular, this study focuses on the investigation of the roll response of FLNG hull in free-decay motions, white noise waves and also in irregular waves. Model tests of the FLNG system in 60%H filling condition excited by both white noise waves and irregular waves combined with steady wind and current have been carried out. Response Amplitude Operators (RAOs) and time histories of the responses are obtained for sway, roll and yaw motions. Obvious Low Frequency (LF) components of the roll motions are observed, which may be out of expectation. To facilitate the physical understanding of this phenomenon, we filter the roll motions at the period of 30 s into two parts: the Wave Frequency (WF) motions and the Low Frequency (LF) motions respectively. The results indicate that the LF motions are closely related to the sway and yaw motions. Possible reasons for the presence of the LF motions of roll have been discussed in detail, through the comparison with the sway and yaw motions. As for the numerical part, the simulation of the modeled case is conducted with the help of the software SESAM®. A good agreement between experiments and calculations is reported within the scope of trends. However, the numerical simulations should be further improved for the prediction of the FLNG system in the heading sea.

  2. Feasibility of landfill gas as a liquefied natural gas fuel source for refuse trucks.

    Science.gov (United States)

    Zietsman, Josias; Bari, Muhammad Ehsanul; Rand, Aaron J; Gokhale, Bhushan; Lord, Dominique; Kumar, Sunil

    2008-05-01

    The purpose of this paper is to develop a methodology to evaluate the feasibility of using landfill gas (LFG) as a liquefied natural gas (LNG) fuel source for heavy-duty refuse trucks operating on landfills. Using LFG as a vehicle fuel can make the landfills more self-sustaining, reduce their dependence on fossil fuels, and reduce emissions and greenhouse gases. Acrion Technologies Inc. in association with Mack Trucks Inc. developed a technology to generate LNG from LFG using the CO2 WASH process. A successful application of this process was performed at the Eco Complex in Burlington County, PA. During this application two LNG refuse trucks were operated for 600 hr each using LNG produced from gases from the landfill. The methodology developed in this paper can evaluate the feasibility of three LFG options: doing nothing, electricity generation, and producing LNG to fuel refuse trucks. The methodology involved the modeling of several components: LFG generation, energy recovery processes, fleet operations, economic feasibility, and decision-making. The economic feasibility considers factors such as capital, maintenance, operational, and fuel costs, emissions and tax benefits, and the sale of products such as surplus LNG and food-grade carbon dioxide (CO2). Texas was used as a case study. The 96 landfills in Texas were prioritized and 17 landfills were identified that showed potential for converting LFG to LNG for use as a refuse truck fuel. The methodology was applied to a pilot landfill in El Paso, TX. The analysis showed that converting LFG to LNG to fuel refuse trucks proved to be the most feasible option and that the methodology can be applied for any landfill that considers this option.

  3. Imprints from the solar cycle on the helium atom and helium pickup ion distributions

    Directory of Open Access Journals (Sweden)

    D. Rucinski

    Full Text Available Neutral interstellar helium atoms penetrate into the solar system almost unaffected by gas–plasma interactions in the heliospheric interface region, and thus can be considered as carriers of original information on the basic parameters (like density, temperature, bulk velocity of the Very Local Interstellar Medium (VLISM. Such information can nowadays be derived from analysis of data obtained from different experimental methods: in situ measurements of He atoms (Ulysses, observations of the solar backscattered He 584 A radiation (EUVE, in situ measurements of He + pickup ions (AMPTE, Ulysses, Wind, SOHO, ACE. In view of the current coordinated international ISSI campaign devoted to the study of the helium focusing cone structure and its evolution, we analyze expected variations of neutral He density, of He + pickup fluxes and of their phase space distributions at various phases of the solar activity cycle based on a realistic time-dependent modelling of the neutral helium and He + pickup ion distributions, which reflect solar cycle-induced variations of the photoionization rate. We show that the neutral helium density values are generally anticorrelated with the solar activity phase and in extreme cases (near the downwind axis the maximum-to-minimum density ratio may even exceed factors of ~ 3 at 1 AU. We also demonstrate that in the upwind hemisphere (at 1 AU and beyond the He + fluxes are correlated with the solar cycle activity, whereas on the downwind side the maximum of the expected flux up to distances of ~ 3 AU occurs around solar minimum epoch, and only further away does the correlation with solar activity become positive. Finally, we present the response of the phase space distribution spectra of He + pickup ions (in the solar wind frame for different epochs of the solar cycle and heliocentric distances from 1 to 5 AU covering the range of Ulysses, Wind and ACE observations.

    Key words. Solar physics, astrophysics and astronomy

  4. Harmonic oscillator model for the helium atom

    CERN Document Server

    Carlsen, Martin

    2015-01-01

    A harmonic oscillator model in four dimensions is presented for the helium atom to estimate the distance to the inner and outer electron from the nucleus, the angle between electrons and the energy levels. The method is algebraic and is not based on the choice of correct trial wave function. Three harmonic oscillators and thus three quantum numbers are sufficient to describe the two-electron system. We derive a simple formula for the energy in the general case and in the special case of the Wannier Ridge. For a set of quantum numbers the distance to the electrons and the angle between the electrons are uniquely determined as the intersection between three surfaces. We show that the excited states converge either towards ionization thresholds or towards extreme parallel or antiparallel states and provide an estimate of the ground state energy.

  5. A Study of Confined Helium Atom

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The helium atom confined by a spherical parabolic potential well is studied employing the adiabatic hyperspherical approach method. Total energies of the ground and three low-excited states are obtained as a function of the confined potential radii. We find that the energies of a spherical parabolic potential well are in good agreement with those of an impenetrable spherical box for the larger confined potential radius. We find also that the confinement may cause accidental degeneracies between levels with different low-excited states and the inversion of the energy values. The results for the three-dimensional spherical potential well and the two-dimensional disc-like potential well are compared with each other. We find that the energy difference between states in a two-dimensional parabolic potential is also obviously larger than the corresponding levels for a spherical parabolic potential.

  6. Radiative corrections to the polarizability of helium.

    Science.gov (United States)

    Łach, Grzegorz; Jeziorski, Bogumił; Szalewicz, Krzysztof

    2004-06-11

    The complete alpha(3) QED correction to the helium atom polarizability is computed assuming an infinite nuclear mass and found to be equal to 0.000030666(3) a.u., with the contribution from the electric-field dependence of the Bethe logarithm amounting to 0.000000193(2) a.u. After including the alpha(2) and alpha(3) corrections for the nuclear recoil and the leading part of the alpha(4) QED correction, we find that the molar polarizability of 4He is 0.51725419(9)(4) cm(3)/mol. The first of the two error bounds is dominated by the uncertainty of alpha(4) and higher-order QED corrections and the second reflects the uncertainty of the Avogadro constant.

  7. The Zeeman effect for helium atom

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The g-factors of the 23P, 21P, and 33P states of the helium atom are calculated by using the vatiational wave functions constructed from the linear combinations of Slater-type basis sets. The relativistic corrections to order α2(a.u.) and the effect of the motion of the center of mass are treated by using first-order perturbation theory. Most of our predicted results are in good agreement with recent results of Yan and Drake, which were obtained by using the wave functions with doubled Hylleraas coordinates. Based on the analysis of the convergence pattern in our calculation, we believe that our predicted value of the δgL-factor for 33P state in 4He, 2.914 15×10-7, ought to be reasonable and accurate, although there are no corresponding experimental data available in the liteature yet to be compared with.

  8. Lunar helium-3 and fusion power

    Energy Technology Data Exchange (ETDEWEB)

    1988-09-01

    The NASA Office of Exploration sponsored the NASA Lunar helium-3 and fusion power Workshop. The meeting was held to understand the potential of using He-3 from the moon for terrestrial fusion power production. It provided an overview, two parallel working sessions, a review of sessions, and discussions. The lunar mining session concluded that mining, beneficiation, separation, and return of He-3 from the moon would be possible but that a large scale operation and improved technology is required. The fusion power session concluded that: (1) that He-3 offers significant, possibly compelling, advantages over fusion of tritium, principally increased reactor life, reduced radioactive wastes, and high efficiency conversion, (2) that detailed assessment of the potential of the D/He-3 fuel cycle requires more information, and (3) D/He-3 fusion may be best for commercial purposes, although D/T fusion is more near term.

  9. Lunar Helium-3 and Fusion Power

    Science.gov (United States)

    1988-01-01

    The NASA Office of Exploration sponsored the NASA Lunar Helium-3 and Fusion Power Workshop. The meeting was held to understand the potential of using He-3 from the moon for terrestrial fusion power production. It provided an overview, two parallel working sessions, a review of sessions, and discussions. The lunar mining session concluded that mining, beneficiation, separation, and return of He-3 from the moon would be possible but that a large scale operation and improved technology is required. The fusion power session concluded that: (1) that He-3 offers significant, possibly compelling, advantages over fusion of tritium, principally increased reactor life, reduced radioactive wastes, and high efficiency conversion, (2) that detailed assessment of the potential of the D/He-3 fuel cycle requires more information, and (3) D/He-3 fusion may be best for commercial purposes, although D/T fusion is more near term.

  10. Helium and carbon isotopes in Indian diamonds

    Science.gov (United States)

    Wiens, R.; Lal, D.; Craig, H.

    1990-09-01

    Helium and carbon isotope measurements in Indian diamonds (from Andhra Pradesh) were carried out using samples that included mined diamonds from primary kimberlite source rocks and alluvial diamonds from river gravel. The He and C isotope concentrations in diamonds from these two sources were compared, and the Indian diamonds were compared to those from other regions. Results indicate that most of the He-3 in the alluvial diamonds is of cosmogenic origin and that the alluvial diamonds may also have a significant He-4 component due to alpha particles implanted during storage in a secondary matrix. One diamond, a mined kimberlite specimen, was found to have the lowest He-4 content (0.018 microcc/g) so far recorded in diamonds.

  11. An Update of the Primordial Helium Abundance

    Science.gov (United States)

    Peimbert, Antonio; Peimbert, Manuel; Luridiana, Valentina

    2015-08-01

    Three of the best determinations of the primordial helium abundance (Yp) are those obtained from low metallicity HII regions by Aver, Olive, Porter, & Skillman (2013); Izotov, Thuan, & Guseva (2014); and Peimbert, Peimbert, & Luridiana (2007). In this poster we update the Yp determination by Peimbert et al. taking into account, among other aspects, recent advances in the determination of the He atomic physical parameters, the temperature structure, the collisional effects of high temperatures on the Balmer lines, as well as the effect of H and He bound-bound absorption.We compare our results with those of Aver et al. and Izotov et al. and point out possible explanations for the differences among the three determinations. We also compare our results with those obtained with the Plank satellite considering recent measurements of the neutron mean life; this comparison has implications on the determination of the number of light neutrino families.

  12. The primordial helium abundance from updated emissivities

    CERN Document Server

    Aver, Erik; Porter, R L; Skillman, Evan D

    2013-01-01

    Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Y_p. The He I emissivities are the foundation of the model of the H II region's emission. Porter, Ferland, Storey, & Detisch (2012) have recently published updated He I emissivities based on improved photoionization cross-sections. We incorporate these new atomic data and update our recent Markov Chain Monte Carlo analysis of the dataset published by Izotov, Thuan, & Stasinska (2007). As before, cuts are made to promote quality and reliability, and only solutions which fit the data within 95% confidence level are used to determine the primordial He abundance. The previously qualifying dataset is almost entirely retained and with strong concordance between the physical parameters. Overall, an upward bias from the new emissivities leads to a decrease in Y_p. In addition, we find a general trend to larger uncertainties in individual objects (due to changes in the emissivities) and an increase...

  13. Helium and Sulfur Hexafluoride in Musical Instruments

    Science.gov (United States)

    Forinash, Kyle; Dixon, Cory L.

    2014-11-01

    The effects of inhaled helium on the human voice were investigated in a recent article in The Physics Teacher.1 As mentioned in that article, demonstrations of the effect are a popular classroom activity. If the number of YouTube videos is any indication, the effects of sulfur hexafluoride on the human voice are equally popular. However, there appears to be little information available on the effects of either of these gases on musical instruments.2 We describe here the results of a student project that involved measuring the frequency shifts in an organ pipe, a trumpet, and a trombone as the result of filling the instruments with these two gases. The project was one of several possible end-of-semester projects required in an elective science of sound course for non-science majors.

  14. Frequency metrology in quantum degenerate helium

    Directory of Open Access Journals (Sweden)

    Vassen Wim

    2013-08-01

    Full Text Available We have measured the absolute frequency of the 1557-nm doubly forbidden transition between the two metastable states of helium, 2 3S1 (lifetime 8000 s and 2 1S0 (lifetime 20 ms, with 1 kHz precision. With an Einstein coefficient of 10−7 s−1 this is one of weakest optical transitions ever measured. The measurement was performed in a Bose-Einstein condensate of 4He* as well as in a Degenerate Fermi Gas of 3He*, trapped in a crossed dipole trap. From the isotope shift we deduced the nuclear charge radius difference between the α-particle and the helion. Our value differs by 4σ with a very recent result obtained on the 2 3S → 2 3P transition.

  15. Photoionization of helium dimers; Photoionisation von Heliumdimeren

    Energy Technology Data Exchange (ETDEWEB)

    Havermeier, Tilo

    2010-06-09

    The helium dimer is one of the most weakly bound systems in the universe. This makes it an interesting quantum mechanical object for investigation. These Van der Waals Clusters can be produced in an expansion of a cryogenic gas jet through a small nozzle into vacuum. In the present experiment we examine the interaction of He dimers with synchrotron radiation at an energy range from 64 to 78 eV. We observed different pathways leading to single ionization of both He atoms of the dimer compound. This two close standing ions begin now to dissociate in cause of their coulomb potential. All charged fragments were detected in coincidence with a COLTRIMS system. Especially Interatomic Coulombic Decay (ICD) and the two step process (TS1) were clearly identified. Furthermore a distribution of the internuclear distance was obtained from the measured Kinetic Energy Release (KER). (orig.)

  16. Photoionizaton of Pure and Doped Helium Nanodroplets

    CERN Document Server

    Mudrich, M

    2014-01-01

    Helium nanodroplets, commonly regarded as the "nearly ideal spectroscopic matrix", are being actively studied for more than two decades now. While they mostly serve as cold, weakly perturbing and transparent medium for high-resolution spectroscopy of embedded molecules, their intrinsic quantum properties such as microscopic superfluidity still are subject-matter of current research. This article reviews recent work on pure and doped He nanodroplets using PI spectroscopy, an approach which has greatly advanced in the past years. While the notion of the ideal spectroscopic matrix mostly no longer holds in this context, photoionization techniques provide detailed insights into the photo-physical properties of pure and doped He nanodroplets and their relaxation dynamics following electronic excitation. Exploiting nowadays available high laser fields, even highly ionized states of matter on the nanoscale can be formed. Our particular focus lies on recent experimental progress including fs time-resolved spectroscop...

  17. Two-phase flows during a discharge of liquefied gases, initially at saturation. Effect of the nature of the fluid; Ecoulements diphasiques lors de la vidange de gaz liquefies initialement a saturation. Influence de la nature du fluide

    Energy Technology Data Exchange (ETDEWEB)

    Alix, P.

    1997-10-03

    In the case of a confinement loss (breakage of a connection piece) on a pressurized liquefied gas tank, a critical two-phase (liquid-vapour) flow is generated. This thesis is aimed at the validation of models describing these flows with various fluids (water, R 11, methanol, ethyl acetate, pure butane, commercial butane), using a pilot experimental plant. Results show that reduced upstream pressure is the main parameter, thus indicating that a model can be validated using minimal fluids. The homogenous models DEM and HRM appear to be more precise

  18. The primordial helium abundance from updated emissivities

    Energy Technology Data Exchange (ETDEWEB)

    Aver, Erik [Department of Physics, Gonzaga University, 502 E Boone Ave, Spokane, WA, 99258 (United States); Olive, Keith A.; Skillman, Evan D. [School of Physics and Astronomy, University of Minnesota, 116 Church St. SE, Minneapolis, MN, 55455 (United States); Porter, R.L., E-mail: aver@gonzaga.edu, E-mail: olive@umn.edu, E-mail: ryanlporter@gmail.com, E-mail: skillman@astro.umn.edu [Department of Physics and Astronomy, University of Georgia, Athens, GA, 30602 (United States)

    2013-11-01

    Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Y{sub p}. The He I emissivities are the foundation of the model of the H II region's emission. Porter, Ferland, Storey, and Detisch (2012) have recently published updated He I emissivities based on improved photoionization cross-sections. We incorporate these new atomic data and update our recent Markov Chain Monte Carlo analysis of the dataset published by Izotov, Thuan, and Stasi'nska (2007). As before, cuts are made to promote quality and reliability, and only solutions which fit the data within 95% confidence level are used to determine the primordial He abundance. The previously qualifying dataset is almost entirely retained and with strong concordance between the physical parameters. Overall, an upward bias from the new emissivities leads to a decrease in Y{sub p}. In addition, we find a general trend to larger uncertainties in individual objects (due to changes in the emissivities) and an increased variance (due to additional objects included). From a regression to zero metallicity, we determine Y{sub p} = 0.2465 ± 0.0097, in good agreement with the BBN result, Y{sub p} = 0.2485 ± 0.0002, based on the Planck determination of the baryon density. In the future, a better understanding of why a large fraction of spectra are not well fit by the model will be crucial to achieving an increase in the precision of the primordial helium abundance determination.

  19. STIRAP on helium: Excitation to Rydberg states

    Science.gov (United States)

    Yuan, Deqian

    Research in optically induced transitions between dierent atomic levels has a long history. For transitions between states driven by a coherent optical eld, the theoretical eciency could be ideally high as 100% but there could be many factors preventing this. In the three state helium atom excitation process, i.e. 23S→33P→nL , the stimulated emission from intermediate state makes it hard to achieve ecient population transfer to the nal state through an intuitive excitation order. One technique to achieve a higher eciency is Stimulated Raman Adiabatic Passage (STIRAP) which is being studied and under research in our lab. Unlike traditional three level excitation processes, STIRAP actually uses a counter intuitive pulsed laser beams timing arrangement. The excitation objects are metastable helium atoms traveling in a vacuum system with a longitudinal velocity of ~ 1070 m/s. We are using a 389 nm UV laser to connect the 23S and the 33P state and a frequency tunable ~790 nm IR laser to connect the 33P state and the dierent Rydberg states. A third 1083 nm wavelength laser beam drives the 23S → 23P transition to transversely separate the residual metastable atoms and the Rydberg atoms for eciency measurements. The data is taken by a stainless steel detector in the vacuum system. As the Rydberg atoms will get ionized by blackbody radiation under room temperature, we can utilize this for their detection. An ion detector sitting on the eld plate is capable to collect the ion signals of the Rydberg atoms for detection. So far the whole system has not been ready for data collection and measurement, so here we are using data and results from previous theses for discussions. The highest transition frequency that has ever been achieved in our lab is around 70% after corrections.

  20. Focused helium-ion-beam-induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Alkemade, P.F.A.; Miro, H. [Delft University of Technology, Kavli Institute of Nanoscience, Delft (Netherlands)

    2014-12-15

    The recent introduction of the helium ion microscope (HIM) offers new possibilities for materials modification and fabrication with spatial resolution below 10 nm. In particular, the specific interaction of He{sup +} ions in the tens of keV energy range with materials - i.e., minimal deflection and mainly energy loss via electronic excitations - renders the HIM a special tool for ion-beam-induced deposition. In this work, an overview is given of all studies of helium-ion-beam-induced deposition (He-IBID) that appeared in the literature before summer 2014. Continuum models that describe the deposition processes are presented in detail, with emphasis on precursor depletion and replenishment. In addition, a Monte Carlo model is discussed. Basic experimental He-IBID studies are critically examined. They show deposition rates of up to 0.1 nm{sup 3}/ion. Analysis by means of a continuum model yields the precursor diffusion constant and the cross sections for beam-induced precursor decomposition and beam-induced desorption. Moreover, it is shown that deposition takes place only in a small zone around the beam impact point. Furthermore, the characterization of deposited materials is discussed in terms of microstructure and resistivity. It is shown that He-IBID material resembles more electron-beam-induced-deposition (EBID) material than Ga-ion-beam-induced-deposition (Ga-IBID) material. Nevertheless, the spatial resolution for He-IBID is in general better than for EBID and Ga-IBID; in particular, proximity effects are minimal. (orig.)

  1. Analytical modeling of helium turbomachinery using FORTRAN 77

    Science.gov (United States)

    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.

  2. Molecular dynamics study of helium bubble pressure in titanium

    Science.gov (United States)

    Zhang, Bao-Ling; Wang, Jun; Hou, Qing

    2011-03-01

    In this paper, the pressure state of the helium bubble in titanium is simulated by a molecular dynamics (MD) method. First, the possible helium/vacancy ratio is determined according to therelation between the bubble pressure and helium/vacancy ratio; then the dependences of the helium bubble pressure on the bubble radius at different temperatures are studied. It is shown that the product of the bubble pressure and the radius is approximately a constant, a result justifying the pressure-radius relation predicted by thermodynamics-based theory for gas bubble. Furthermore, a state equation of the helium bubble is established based on the MD calculations. Comparison between the results obtained by the state equation and corresponding experimental data shows that the state equation can describe reasonably the state of helium bubble and thus could be used for Monte Carlo simulations of the evolution of helium bubble in metals. Project supported by the National Natural Science Foundation of China (Grant No. 10775101) and National Magnetic Confinement Fusion Program of China (Grant No. 2009GB106004).

  3. European standardization activities on safety of liquid helium cryostats

    CERN Document Server

    CERN. Geneva

    2016-01-01

    This talk gives a general overview on the challenges of designing safety units for liquid helium cryostats with regard to existing industry standards. It reviews the work of a national working group that published the technical guideline DIN SPEC 4683 in April 2015, which is dedicated to the particular conditions in liquid helium cryostats. Based on both this guideline and equivalent documents from e.g. CEA, CERN, a working group is being formed at the European Committee for Standardization, associated to CEN/TC 268, which will work on a European standard on safety of liquid helium cryostats. The actual status and the schedule of this project are presented.

  4. Superfluid Helium On-Orbit Transfer (SHOOT) operations

    Science.gov (United States)

    Kittel, P.; Dipirro, M. J.

    1989-01-01

    The in-flight tests and the operational sequences of the Superfluid Helium On-Orbit Transfer (SHOOT) experiment are outlined. These tests include the transfer of superfluid helium at a variety of rates, the transfer into cold and warm receivers, the operation of an extravehicular activity coupling, and tests of a liquid acquisition device. A variety of different types of instrumentation will be required for these tests. These include pressure sensors and liquid flow meters that must operate in liquid helium, accurate thermometry, two types of quantity gauges, and liquid-vapor sensors.

  5. Helium at white dwarf photospheric conditions: preliminary laboratory results

    CERN Document Server

    Schaeuble, Marc; Gomez, Thomas A; Winget, Don E; Montgomery, Michael H; Bailey, James E

    2016-01-01

    We present preliminary results of an experimental study exploring helium at photospheric conditions of white dwarf stars. These data were collected at Sandia National Laboratories' Z-machine, the largest x-ray source on earth. Our helium results could have many applications ranging from validating current DB white dwarf model atmospheres to providing accurate He pressure shifts at varying temperatures and densities. In a much broader context, these helium data can be used to guide theoretical developments in new continuum-lowering models for two-electron atoms. We also discuss future applications of our updated experimental design, which enables us to sample a greater range of densities, temperatures, and gas compositions.

  6. Development of 18 K helium refrigeration system for CERN

    CERN Document Server

    CERN. Geneva

    2004-01-01

    The Conseil Europeen pour Ia Recherche Nucleaire (CERN) placed an order for a 1.8 K helium refrigeration system with IHI for the Large Hadron Collider project in 1999. IHI formed a consortium with Linde Kryotechnik AG (Switzerland), which has long experience with helium refrigeration systems. IHI designed and manufactured cold compressors based on leading technologies and expertise for turbo machinery. The cold compressor has the highest efficiency in the world. This paper describes the 1.8 K helium refrigeration system and performance test results at CERN. (5 refs).

  7. Solvation of Na+, K+, and Their Dimers in Helium

    OpenAIRE

    An der Lan, Lukas; Bartl, Peter; Leidlmair, Christian; Jochum, Roland; Denifl, Stephan; Echt, Olof; Scheier, Paul

    2012-01-01

    Helium atoms bind strongly to alkali cations which, when embedded in liquid helium, form so-called snowballs. Calculations suggest that helium atoms in the first solvation layer of these snowballs form rigid structures and that their number (n) is well defined, especially for the lighter alkalis. However, experiments have so far failed to accurately determine values of n. We present high-resolution mass spectra of Na+He n , K+He n , Na2 +He n and K2 +He n , formed by electron ionization of do...

  8. Method for laser spectroscopy of metastable pionic helium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Hori, M., E-mail: Masaki.Hori@mpq.mpg.de; Sótér, A.; Aghai-Khozani, H. [Max-Planck-Institut für Quantenoptik (Germany); Barna, D. [CERN (Switzerland); Dax, A. [Paul Scherrer Institut (Switzerland); Hayano, R. S.; Murakami, Y.; Yamada, H. [University of Tokyo, Department of Physics (Japan)

    2015-08-15

    The PiHe collaboration is currently attempting to carry out laser spectroscopy of metastable pionic helium atoms using the high-intensity π{sup −} beam of the ring cyclotron facility of the Paul Scherrer Institute. These atoms are heretofore hypothetical three-body Coulomb systems each composed of a helium nucleus, a π{sup −} occupying a Rydberg state, and an electron occupying the 1s ground state. We briefly review the proposed method by which we intend to detect the laser spectroscopic signal. This complements our experiments on metastable antiprotonic helium atoms at CERN.

  9. Helium at White Dwarf Photospheric Conditions: Preliminary Laboratory Results

    Science.gov (United States)

    Schaeuble, M.; Falcon, R. E.; Gomez, T. A.; Winget, D. E.; Montgomery, M. H.; Bailey, J. E.

    2017-03-01

    We present preliminary results of an experimental study exploring helium at photospheric conditions of white dwarf stars. These data were collected at Sandia National Laboratories' Z-machine, the largest x-ray source on earth. Our helium results could have many applications ranging from validating current DB white dwarf model atmospheres to providing accurate He pressure shifts at varying temperatures and densities. In a much broader context, these helium data can be used to guide theoretical developments in new continuum-lowering models for two-electron atoms. We also discuss future applications of our updated experimental design, which enables us to sample a greater range of densities, temperatures, and gas compositions.

  10. High resolution spectroscopy of six new extreme helium stars

    Science.gov (United States)

    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.

  11. Nucleation, solvation and boiling of helium excimer clusters

    CERN Document Server

    Luna, Luis G Mendoza; Watkins, Mark J; Bonifaci, Nelly; Aitken, Frederic; von Haeften, Klaus

    2015-01-01

    Helium excimers generated by a corona discharge were investigated in the gas and normal liquid phases of helium as a function of temperature and pressure between 3.8 and 5.0 K and 0.2 and 5.6 bar. Intense fluorescence in the visible region showed the rotationally resolved $d^3\\Sigma_u^+ \\rightarrow b^3\\Pi_g$ transition of He$_2^*$. With increasing pressure, the rotational lines merged into single features. The observed pressure dependence of linewidths, shapes and lineshifts established phases of coexistence and separation of excimer-helium mixtures, providing detailed insight into nucleation, solvation and boiling of He$_2^*$-He$_n$ clusters.

  12. Performance of Oil-Injected Scroll Compressors for Helium Refrigerators

    Science.gov (United States)

    Shiibayashi, Masao; Izunaga, Yasushi; Sado, Shintaro

    In recent years there arises growing demand of helium liquefaction refrigerators for the magnetic resonance imaging systems, magnetically levitated vehicles and other systems using superconducting magnet. From this background, a small size, scroll type of hermetic helium compressor capable of compressing helium gas to the pressure ratio of 20 in a single stage is developed. Main features of this compressor are as follows. 1) Discharge capacity can be varied from 7 to 20 Nm3/h by changing driving motor frequency from 30 to 80 Hz. 2) The overall adiabatic efficiency showed 72%∼79% under the pressure ratio range of 11∼20 at 60 Hz using oil injection cooling device.

  13. Roles and expectations of cold compressor for helium refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Saji, Nobuyoshi; Asakura, Hiroshi; Yoshinaga, Seiichiro; Ishizawa, Takehiko [Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama, Kanagawa (Japan)

    2002-12-01

    Since around 1970, cryogenic systems have required the use of cold compressors. The requirement appeared for two reasons. The first was reduce the pressure of liquid helium with the intention of realizing the stable operation of large superconducting magnets with the best superconducting ability by decreasing operating temperature. The other was to improve the reliability of helium refrigerator compressors by introducing a turbo-compressor with oil-free bearings. This paper describes the circumstances and particular development of cold compressors, requirements related to helium refrigeration systems and cold compressors and future prospects. (author)

  14. International thermodynamic tables of the fluid state helium-4

    CERN Document Server

    Angus, S; McCarty, R D

    2013-01-01

    International Thermodynamic Tables of the Fluid State Helium-4 presents the IUPAC Thermodynamic Tables for the thermodynamic properties of helium. The IUPAC Thermodynamic Tables Project has therefore encouraged the critical analysis of the available thermodynamic measurements for helium and their synthesis into tables. This book is divided into three chapters. The first chapter discusses the experimental results and compares with the equations used to generate the tables. These equations are supplemented by a vapor pressure equation, which represents the 1958 He-4 scale of temperature that is

  15. ENVIR IONMENTAL ISSUES OF COMPETITIVENESS OF RUSSIAN MULTINATIONAL OIL AND GAS CORPORATIONS IN LIQUEFIED NATURAL GAS MARKETS

    Directory of Open Access Journals (Sweden)

    N. A. Piskulova

    2011-01-01

    Full Text Available Owing to tough state environmental management requirements and ecological regulations, oil and gas multinational corporations (MNC make more and more attempts to mitigate negative environmental impacts resulting from their industrial activities, their competitiveness beingstrengthened therewith. The use of liquefied natural gas (LNG is associated with less environmental impact in comparison with oil and coal, particularly so far as the hotbed effect is concerned. In the field of innovative technological development, Russian MNC drag so far well behind most advanced western corporations who provide for less negative impact of their production activities upon environment.

  16. Investigation on the heat transfer characteristics during flow boiling of liquefied natural gas in a vertical micro-fin tube

    Science.gov (United States)

    Xu, Bin; Shi, Yumei; Chen, Dongsheng

    2014-03-01

    This paper presents an experimental investigation on the heat transfer characteristics of liquefied natural gas flow boiling in a vertical micro-fin tube. The effect of heat flux, mass flux and inlet pressure on the flow boiling heat transfer coefficients was analyzed. The Kim, Koyama, and two kinds of Wellsandt correlations with different Ftp coefficients were used to predict the flow boiling heat transfer coefficients. The predicted results showed that the Koyama correlation was the most accurate over the range of experimental conditions.

  17. Gaseous Helium Reclamation at Rocket Test Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ability to restore large amounts of vented gaseous helium (GHe) at rocket test sites preserves the GHe and reduces operating cost. The used GHe is vented into...

  18. Helium-3 Microscopic Optical Model Potential Based on Skyrme Interaction

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The helium-3 microscopic optical potential is obtained by Green function method through nuclear matter approximation and local density approximation based on the effective Skyrme interaction. The reaction cross

  19. Transport and extraction of radioactive ions stopped in superfluid helium

    CERN Document Server

    Huang Wan Xia; Gloos, K; Takahashi, N; Arutyunov, K; Pekola, J P; Äystö, J

    2003-01-01

    A new approach to convert a high energy beam to a low energy one, which is essential for the next generation radioactive ion beam facilities, has been proposed and tested at Jyvaeskylae, Finland. An open sup 2 sup 2 sup 3 Ra alpha-decay-recoil source has been used to produce radioactive ions in superfluid helium. The alpha spectra demonstrate that the recoiling sup 2 sup 1 sup 9 Rn ions have been extracted out of liquid helium. This first observation of the extraction of heavy positive ions across the superfluid helium surface was possible thanks to the high sensitivity of radioactivity detection. An efficiency of 36% was obtained for the ion extraction out of liquid helium.

  20. One of the Helium Liquifiers in the North Area

    CERN Multimedia

    1979-01-01

    Several Helium Liquifiers were installed in the North Area to cool superconducting magnets used in the experiments. At center top is M.Dykes, at bottom right J.Dozio. See CERN Annual Report 1979 p.82.

  1. Turbine flowmeter for liquid helium with the rotor magnetically levitated

    Science.gov (United States)

    Rivetti, A.; Martini, G.; Goria, R.; Lorefice, S.

    A turbine flowmeter with no mechanical contact between rotor and body is described, to be used as a reference standard in our liquid helium flow rate calibration facility. The absence of contact, zeroing the bearings friction factor, ensures a good measurement repeatability, even at very low liquid helium flow rate values. The rotor is magnetically suspended by the Meissner effect: at liquid helium temperatures two magnetic fields generate sustaining forces against the surface of the two rotor ends, which are made of niobium. Due to the repulsive nature of the acting forces, the rotor equilibrium is intrinsically stable and no external electronics are required for its levitation. A particular configuration of the superconducting windings and of the rotor ends allow the rotor to levitate and hold good axial and radial stability. A detailed description of the solutions adopted for the realization of the prototype and the operation conditions are reported. The first results, made with the absolute liquid helium calibration facility, are shown.

  2. Self-Calibrating Vector Helium Magnetometer (SVHM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR proposal describes proposed development of a conceptual design for a Self-Calibrating Vector Helium Magnetometer (SVHM) for design and fabrication...

  3. Self-Calibrating Vector Helium Magnetometer (SVHM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase 2 SBIR proposal describes the design, fabrication and calibration of a brass-board Self-Calibrating Vector Helium Magnetometer (SVHM). The SVHM instrument...

  4. Communication: Barium ions and helium nanodroplets: solvation and desolvation.

    Science.gov (United States)

    Zhang, Xiaohang; Drabbels, Marcel

    2012-08-07

    The solvation of Ba(+) ions created by the photoionization of barium atoms located on the surface of helium nanodroplets has been investigated. The excitation spectra corresponding to the 6p (2)P(1/2) ← 6s (2)S(1/2) and 6p (2)P(3/2) ← 6s (2)S(1/2) transitions of Ba(+) are found to be identical to those recorded in bulk He II [H. J. Reyher, H. Bauer, C. Huber, R. Mayer, A. Schafer, and A. Winnacker, Phys. Lett. A 115, 238 (1986)], indicating that the ions formed at the surface of the helium droplets become fully solvated by the helium. Time-of-flight mass spectra suggest that following the excitation of the solvated Ba(+) ions, these are being ejected from the helium droplets either as bare Ba(+) ions or as small Ba(+)He(n) (n < 20) complexes.

  5. General mechanism for helium blistering involving displaced atom transport

    Energy Technology Data Exchange (ETDEWEB)

    McDonell, W.R.

    1979-01-01

    A mechanism developed to account for formation of vertically elongated blisters in high displacement environments produced by /sup 252/Cf alpha particles and fission fragments has been extended to formation of done-shaped blisters in the low displacement environments produced by simple helium ion beams. In this mechanism, transport of displaced atoms to relieve compressive stresses in the helium-implanted layer allows interconnections of small, subsurface bubbles to form the blister cavity. The same transport may cause thickening of the blister caps at low implantation energies. The transition from dome-shaped to vertically elongated blistering occurs between the 300 and 3000 displacements per helium atom produced by simple helium ions and /sup 252/Cf radiations respectively.

  6. Heat capacity and thermal expansion of water and helium

    Science.gov (United States)

    Putintsev, N. M.; Putintsev, D. N.

    2017-04-01

    Original expressions for heat capacity CV and its components, vibrational and configurational components of thermal expansion coefficient were established. The values of CV, Cvib, Cconf, αvib and αconf for water and helium 4He were calculated.

  7. Heat transfer to near-critical helium in horizontal channels

    Energy Technology Data Exchange (ETDEWEB)

    Dolgoy, M.L.; Kirichenko, Y.A.; Sklovsky, Y.B.; Troyanov, A.M.; Chernyakov, P.S. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur)

    1983-03-01

    Experimental results on heat transfer and pressure losses during a forced motion of helium of near-critical state parameters in a horizontal channel are reported. A method of calculation of temperature and pressure distributions along the channel is proposed.

  8. The effects of He I 10830 on helium abundance determinations

    CERN Document Server

    Aver, Erik; Skillman, Evan D

    2015-01-01

    Observations of helium and hydrogen emission lines from metal-poor extragalactic H II regions provide an independent method for determining the primordial helium abundance, Y_p. Traditionally, the emission lines employed are in the visible wavelength range, and the number of suitable lines is limited. Furthermore, when using these lines, large systematic uncertainties in helium abundance determinations arise due to the degeneracy of physical parameters, such as temperature and density. Recently, Izotov, Thuan, & Guseva (2014) have pioneered adding the He 10830 infrared emission line in helium abundance determinations. The strong electron density dependence of He 10830 makes it ideal for better constraining density, potentially breaking the degeneracy with temperature. We revisit our analysis of the dataset published by Izotov, Thuan, & Stasinska (2007) and incorporate the newly available observations of He 10830 by scaling them using the observed-to-theoretical Paschen-gamma ratio. The solutions are b...

  9. Gaseous Helium Reclamation at Rocket Test Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — GHe reclamation is critical in reducing operating costs at rocket engine test facilities. Increases in cost and shortages of helium will dramatically impact testing...

  10. High-Range Scalar Helium Magnetometer (HSHM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal describes development of a conceptual design for a High-range Scalar Helium Magnetometer (HSHM) for the field range +/-16 Gauss. The HSHM...

  11. Study of Thermal Desorption of Helium from Hydrogenated Zirconium

    Institute of Scientific and Technical Information of China (English)

    SUN Wei-Ming; WEI Yu-Cheng; SHI Li-Qun

    2006-01-01

    @@ A new method prepared for helium and hydrogen co-containing Zr films is presented to simulate aging metal tritides, in which direct current magnetron sputtering with a He/H/Ar mixture is used. The retained amount and depth profiles of helium and hydrogen are determined by elastic recoil detection analysis. Thermal desorption spectrometry is applied to investigate He thermal release and the effect of hydrogen. It is found that the hightemperature peaks with a large mount of helium release obviously shifted toward lower temperature at high hydrogen concentration, especially at the hydride transformation region, and that the shapes of the release peaks also changed due to the additional hydrogen. However, at the low-temperature releasing region the peak intense decreases when phase transformation takes place. The mechanism of helium thermal release and the effect of hydrogen are also discussed.

  12. Helium Controller%Helium系列处理器

    Institute of Scientific and Technical Information of China (English)

    刘坛春; 石冰心

    2002-01-01

    @@ Helium系列处理器是Virata公司(现在是GlobespanVirata)的通信处理器,主要为针对宽频调制解调器、桥接器与住宅路由器在不同价格、效能与产品特性上的市场需求,主要有He-liuml00,Helium200,Helium210-80.

  13. Corrections to the Nonrelativistic Ground Energy of a Helium Atom

    Institute of Scientific and Technical Information of China (English)

    段一士; 刘玉孝; 张丽杰

    2004-01-01

    Considering the nuclear motion, we present the nonrelativistic ground energy of a helium atom by using a simple effective variational wavefunction with a flexible parameter k. Based on the result, the relativistic and radiative corrections to the nonrelativistic Hamiltonian are discussed. The high precision value of the helium ground energy is evaluated to be -2.90338 a.u. With the relative error 0.00034%.

  14. Density shift and broadening of transition lines in antiprotonic helium

    Science.gov (United States)

    Bakalov; Jeziorski; Korona; Szalewicz; Tchoukova

    2000-03-13

    The density shift and broadening of the transition lines of antiprotonic helium have been evaluated in the impact approximation using an interatomic potential calculated ab initio with the symmetry-adapted perturbation theory. The results help to remove an uncertainty of up to 10 ppm in the laser spectroscopy data on antiprotonic helium and are of importance in experimental tests of bound state QED and CPT invariance.

  15. Wave packet dynamics of potassium dimers attached to helium nanodroplets

    OpenAIRE

    Claas, P.; Droppelmann, G.; Schulz, C. P.; Mudrich, M.; Stienkemeier, F.

    2006-01-01

    The dynamics of vibrational wave packets excited in K$_2$ dimers attached to superfluid helium nanodroplets is investigated by means of femtosecond pump-probe spectroscopy. The employed resonant three-photon-ionization scheme is studied in a wide wavelength range and different pathways leading to K$^+_2$-formation are identified. While the wave packet dynamics of the electronic ground state is not influenced by the helium environment, perturbations of the electronically excited states are obs...

  16. Helium segregation on surfaces of plasma-exposed tungsten.

    Science.gov (United States)

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

    2016-02-17

    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.

  17. Helium Behaviour in Waste Conditioning Matrices during Thermal Annealing

    Energy Technology Data Exchange (ETDEWEB)

    Wiss, Thierry A.; Hiernaut, J-P; Damen, P; Lutique, Stphanie; Fromknecht, R; Weber, William J.

    2006-06-30

    Reprocessing of spent fuel produces high level waste including minor actinides and long living fission products that might be disposed in waste conditioning matrices. Several natural mineral phases were proven to be able to incorporate fission products or actinides in their crystalline structure for long periods of time. In this study, synthetic compounds of zirconolite (CaZrTi2O7) and pyrochlores (Gd2Ti2O7 and Nd2Zr2O7) were fabricated and doped with the short-lived alpha-emitter 244Cm to increase the total amount of helium and damage generated in a laboratory time scale. Helium implantations were also used to simulate the damage caused by the alpha-decay and the build-up of helium in the matrix. The samples were annealed in a Knudsen cell, and the helium release profile interpreted in conjunction with radiation damage studies and previous analysis of annealing behaviour. Several processes like diffusion, trapping or phase changes could then be attributed to the helium behaviour depending on the material considered. Despite high damage and large amount of helium accumulated, the integrity of the studied materials was preserved during storage.

  18. Helium behaviour in waste conditioning matrices during thermal annealing

    Science.gov (United States)

    Wiss, T. A. G.; Hiernaut, J.-P.; Damen, P. M. G.; Lutique, S.; Fromknecht, R.; Weber, W. J.

    2006-06-01

    Reprocessing of spent fuel produces high level waste including minor actinides and long living fission products that might be disposed in waste conditioning matrices. Several natural mineral phases were proven to be able to incorporate fission products or actinides in their crystalline structure for long periods of time. In this study, synthetic compounds of zirconolite (CaZrTi2O7) and pyrochlores (Gd2Ti2O7 and Nd2Zr2O7) were fabricated and doped with the short-lived alpha-emitter 244Cm to increase the total amount of helium and damage generated in a laboratory time scale. Helium implantations were also used to simulate the damage caused by the alpha-decay and the build-up of helium in the matrix. The samples were annealed in a Knudsen cell, and the helium release profile interpreted in conjunction with radiation damage studies and previous analysis of annealing behaviour. Several processes like diffusion, trapping or phase changes could then be attributed to the helium behaviour depending on the material considered. Despite high damage and large amount of helium accumulated, the integrity of the studied materials was preserved during storage.

  19. Atomistic simulation of helium bubble nucleation in palladium

    Energy Technology Data Exchange (ETDEWEB)

    Wang Liang [Department of Applied Physics, Hunan University, Changsha 410082 (China); Hu, Wangyu [Department of Applied Physics, Hunan University, Changsha 410082 (China)], E-mail: wangyuhu2001cn@yahoo.com.cn; Xiao Shifang [Department of Applied Physics, Hunan University, Changsha 410082 (China)], E-mail: sfxiao@yahoo.com.cn; Yang Jianyu [Department of Maths and Physics, Hunan Institute of Engineering, Xiangtan 411104 (China); Deng Huiqiu [Department of Applied Physics, Hunan University, Changsha 410082 (China)

    2009-09-15

    A palladium crystal has been constructed with 11808 atoms. 55 helium atoms occupied the octahedral position of palladium crystal are introduced and retained in a spherical region. Molecular dynamic simulations are performed in a constant temperature and constant volume ensemble (NVT) with temperature controlled by Nose-Hoover thermostat. The interactions between palladium atoms are described with modified analytic embedded atom method (MAEAM), the interactions between palladium atom and helium atom are in the form of Morse potential, and the interactions between helium atoms are in the form of L-J potential function. With the analysis of the radial distribution function (RDF) and microstructure, it reveals that some of helium atoms form a series of clusters with different size, and the nucleation core is random at low temperature, and which is the embryo of helium bubble. Increasing temperature can accelerate the process of bubble nucleation, and the clusters will aggregate and coalesce into a bigger one in which there are no palladium atoms, and it is considered as a helium bubble.

  20. Cryocooled Facilities for Superconducting Coils Testing in Gaseous Helium

    Science.gov (United States)

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

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

  1. Suspension of superfluid helium using cesium-coated surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Williams, M.C.; Giese, C.F.; Halley, J.W. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    1996-03-01

    We report results of an experiment which demonstrates that a layer of superfluid helium can be suspended over a cesium-coated orifice. By measuring the layer thickness with a capacitance bridge, we have shown in two runs that fluid layers up to 2 mm thick were suspended over a 70-{mu}m-diam cesium-coated orifice in a platinum foil for over 2 h in a cryostat held at 1.2 K. The effect depends on the recently established fact that superfluid helium does not wet cesium-coated surfaces. As a consequence, superfluid helium is expected to form a stable meniscus across such a cesium-coated hole. The observed depths of suspended helium are consistent with a simple theoretical model based on this picture. We briefly discuss the possible application of this method to the performance of a proposed experiment to study quantum coherence in superfluid helium by directing pulsed beams of helium atoms at such a suspended layer of fluid. {copyright} {ital 1996 The American Physical Society.}

  2. Formation of the helium extreme-UV resonance lines

    Science.gov (United States)

    Golding, T. P.; Leenaarts, J.; Carlsson, M.

    2017-01-01

    Context. While classical models successfully reproduce intensities of many transition region lines, they predict helium extreme-UV (EUV) line intensities roughly an order of magnitude lower than the observed value. Aims: Our aim is to determine the relevant formation mechanism(s) of the helium EUV resonance lines capable of explaining the high intensities under quiet Sun conditions. Methods: We synthesised and studied the emergent spectra from a 3D radiation-magnetohydrodynamics simulation model. The effects of coronal illumination and non-equilibrium ionisation of hydrogen and helium are included self-consistently in the numerical simulation. Results: Radiative transfer calculations result in helium EUV line intensities that are an order of magnitude larger than the intensities calculated under the classical assumptions. The enhanced intensity of He iλ584 is primarily caused by He ii recombination cascades. The enhanced intensity of He iiλ304 and He iiλ256 is caused primarily by non-equilibrium helium ionisation. Conclusions: The analysis shows that the long standing problem of the high helium EUV line intensities disappears when taking into account optically thick radiative transfer and non-equilibrium ionisation effects.

  3. Determination of trace anions in liquefied petroleum gas using liquid absorption and electrokinetic migration for enrichment followed by ion chromatography.

    Science.gov (United States)

    Li, Meilan; Yang, Jianmin; Li, Hai-Fang; Lin, Jin-Ming

    2012-06-01

    A simple sample enrichment technique, electrokinetic migration enrichment in single phase using a designed device, coupled with ion chromatography is presented for the determination of four anions (H(2)PO(4)(-), Cl(-), NO(3)(-), and SO(4)(2-)) in liquefied petroleum gas by liquid adsorption. The electrokinetic migration enrichment is based on the phenomenon of ion electrokinetic migration to the opposite electrode. When the anions migrated to the anode in a smaller volume chamber under the electric field, the concentration was realized. The main parameters affecting enrichment efficiency of applied voltage and enrichment time were investigated. The ion chromatography condition for anions separation was also studied. Under the optimal electrokinetic migration enrichment and ion chromatography conditions, the four anions were detected simultaneously with good linear relationship (r(2) = 0.9908-0.9968) and high precisions (less than 5% of the relative standard deviations of peak areas). The limits of detection of anions (S/N of 3) were in the range of 8-600 μg L(-1). The enrichment factors of the four anions ranged from 3.1 to 5.8. The established method was successfully applied to the analysis of the trace anions in liquefied petroleum gas by liquid adsorption with satisfactory results. The advantages of this method are simple operation and low cost.

  4. The Fire Protection Design of Liquefied Hydrocarbon Spherical Tank%液化烃球罐的消防设计

    Institute of Scientific and Technical Information of China (English)

    邵军

    2012-01-01

    Through the analysis of the composition and fire characteristics of liquefied hydrocarbon,the fire control cooling method and system of liquefied hydrocarbon spherical tank were described.According to the design experience,taking the spherical tank of 3000 m3 as an example,starting from the protection area of water spray cone,the number of nozzles and water quantity of the cooling device was estimated,and the economy and rationality of the entire cooling system was back calculated.%通过分析液化烃的组成和着火特点,阐述液化烃球罐发生火灾时的消防冷却方式及系统组成,并根据自己的设计经历,以容积为3000 m3的球罐为例,从水雾喷头水雾锥的保护面积入手,估算出冷却装置所需要的喷头数量和水量,反向核算整个冷却系统的经济性和合理性。

  5. Effect of temperature and time on microstructure and surface functional groups of activated carbon fibers prepared from liquefied wood

    Directory of Open Access Journals (Sweden)

    Wenjing Liu

    2012-11-01

    Full Text Available Activated carbon fibers were prepared from liquefied wood through stream activation. The effects of activation temperature and time on the microstructure and surface functional groups of the liquefied wood activated carbon fibers (LWACFs were studied using analysis of burning behavior, X-ray diffraction, nitrogen adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and SEM. The results showed that the burn-off value of the LWACFs increased gradually with the increase in temperature or time. All the LWACFs were far from being structurally graphitized, and in general, as temperature or time increased, the degree of graphitization and thickness of crystal structure increased. In addition, the LWACFs possessed rich micropores, and their specific surface area, pore volume, micropore size, and mesopore quantity were directly related to the activation temperature or time. The maximum specific surface area was found to be 2641 m2/g. The fractal dimension values of all samples were close to 3, indicating that their surfaces were very rough. Furthermore, with an increase in temperature or time, the elemental content of carbon increased, while that of oxygen decreased. Meanwhile, as the temperature or time increased, the relative content of graphitic carbon decreased, whereas that of carbon bonded to oxygen-containing functions increased. The surface of samples prepared at higher temperature or with longer time formed a considerable amount of holes.

  6. Measurement of helium production cross sections of iron for d-T neutrons by helium accumulation method

    Energy Technology Data Exchange (ETDEWEB)

    Takao, Yoshiyuki; Kanda, Yukinori; Nagae, Koji; Fujimoto, Toshihiro [Kyushu Univ., Fukuoka (Japan); Ikeda, Yujiro

    1997-03-01

    Helium production cross sections of Iron were measured by helium accumulation method for neutron energies from 13.5 to 14.9 MeV. Iron samples were irradiated with FNS, an intense d-T neutron source of JAERI. As the neutron energy varies according to the emission angle at the neutron source, the samples were set around the neutron source and were irradiated by neutrons of different energy depending on each sample position. The amount of helium produced in a sample was measured by Helium Atoms Measurement System at Kyushu University. The results of this work are in good agreement with other experimental data in the literature and also compared with the evaluated values in JENDL-3. (author)

  7. Design of the Helium Purifier for IHEP-ADS Helium Purification System

    OpenAIRE

    2015-01-01

    Helium Purification System is an important sub-system in the Accelerator Driven Subcritical System of the Institute of High Energy Physics(IHEP ADS). The purifier is designed to work at the temperature of 77K. The purifier will work in a flow rate of 5g/s at 20MPa in continuous operation of 12 hours. The oil and moisture are removed by coalescing filters and a dryer, while nitrogen and oxygen are condensed by a phase separator and then adsorbed in several activated carbon adsorption cylinders...

  8. Near field characteristics of buoyant helium plumes

    Indian Academy of Sciences (India)

    Kuchimanchi K Bharadwaj; Debopam Das; Pavan K Sharma

    2015-05-01

    Puffing and entrainment characteristics of helium plumes emanating out into ambient air from a circular orifice are investigated in the present study. Velocity and density fields are measured across a diametric plane using Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF) respectively in phase resolved manner. Experiments are performed in Froude numbers range 0.2–0.4 and for Reynolds numbers 58–248. Puffing frequency measurements reveal that the plume puffing frequencies are insensitive to the plume exit conditions, since the instability is buoyancy driven. The frequencies obtained in the present case are in agreement with frequencies obtained by Cetegen & Kasper (1996) for plumes originating from circular nozzles of various L/D ratios. Velocity and density measurements reveal that toroidal vortex formed during a puffing cycle entrains ambient air as it traverses downstream and this periodic engulfment governs the entrainment mechanism in pulsating plumes. The obtained velocity and density fields are used to calculate mass entrainment rates. It is revealed that though the flow is unsteady, the contribution of unsteady term in mass conservation to entrainment is negligible, and it becomes zero over a puff cycle. Finally, an empirical relation for variation of mass entrainment with height has been proposed, in which the non-dimensional mass entrainment is found to follow a power law with the non-dimensional height.

  9. Helium Loop Cooling Channel Hydraulic Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Olivas, Eric Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Morgan, Robert Vaughn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-02

    New methods for generating ⁹⁹Mo are being explored in an effort to eliminate proliferation issues and provide a domestic supply of ⁹⁹mTc for medical imaging. Electron accelerating technology is used by sending an electron beam through a series of ¹⁰⁰Mo targets. During this process a large amount of heat is created, which directly affects the operating temperature set for the system. In order to maintain the required temperature range, helium gas is used to serve as a cooling agent that flows through narrow channels between the target disks. Currently we are tailoring the cooling channel entrance and exits to decrease the pressure drop through the targets. Currently all hardware has be procured and manufactured to conduct flow measurements and visualization via solid particle seeder. Pressure drop will be studied as a function of mass flow and diffuser angle. The results from these experiments will help in determining target cooling geometry and validate CFD code results.

  10. Classical helium atom with radiation reaction.

    Science.gov (United States)

    Camelio, G; Carati, A; Galgani, L

    2012-06-01

    We study a classical model of helium atom in which, in addition to the Coulomb forces, the radiation reaction forces are taken into account. This modification brings in the model a new qualitative feature of a global character. Indeed, as pointed out by Dirac, in any model of classical electrodynamics of point particles involving radiation reaction one has to eliminate, from the a priori conceivable solutions of the problem, those corresponding to the emission of an infinite amount of energy. We show that the Dirac prescription solves a problem of inconsistency plaguing all available models which neglect radiation reaction, namely, the fact that in all such models, most initial data lead to a spontaneous breakdown of the atom. A further modification is that the system thus acquires a peculiar form of dissipation. In particular, this makes attractive an invariant manifold of special physical interest, the zero-dipole manifold that corresponds to motions in which no energy is radiated away (in the dipole approximation). We finally study numerically the invariant measure naturally induced by the time-evolution on such a manifold, and this corresponds to studying the formation process of the atom. Indications are given that such a measure may be singular with respect to that of Lebesgue.

  11. Abundance analyses of cool extreme helium stars

    CERN Document Server

    Pandey, G; Lambert, D L; Jeffery, C S; Asplund, M; Pandey, Gajendra; Lambert, David L.; Asplund, Martin

    2001-01-01

    Extreme helium stars (EHe) with effective temperatures from 8000K to 13000K are among the coolest EHe stars and overlap the hotter R CrB stars in effective temperature. The cool EHes may represent an evolutionary link between the hot EHes and the R CrBs. Abundance analyses of four cool EHes are presented. To test for an evolutionary connection, the chemical compositions of cool EHes are compared with those of hot EHes and R CrBs. Relative to Fe, the N abundance of these stars is intermediate between those of hot EHes and R CrBs. For the R CrBs, the metallicity M derived from the mean of Si and S appears to be more consistent with the kinematics than that derived from Fe. When metallicity M derived from Si and S replaces Fe, the observed N abundances of EHes and R CrBs fall at or below the upper limit corresponding to thorough conversion of initial C and O to N. There is an apparent difference between the composition of R CrBs and EHes; the former having systematically higher [N/M] ratios. The material present...

  12. An NMR study of adsorbed helium films

    Science.gov (United States)

    Kent, Anthony Joseph

    The properties of sub-monolayer Helium-3 films adsorbed on two totally different but planar substrates, Mylar† film and exfoliated graphite have been studied using NMR. The nuclear magnetic relaxation times T1 and T 2 have been measured as functions of fractional monolayer completion, temperature, substrate plane orientation and Larmor frequency using a specially designed and constructed NMR spectrometer system. The results obtained with a Mylar film substrate are consistent3with the formation of patches of solid 3He at regions of preferential adsorption on the substrate. Measurements of T2 m very low coverage 3He films on exfoliated graphite also indicate that the adsorbate forms areas of relatively high density solid, in agreement with the thermodynamic analysis of Elgin and Goodstein. Finally, detailed measurements of T2 as a function of all of the above parameters at low areal densities will help us to characterise the relaxation processes for the fluid phase of 33He on exfoliated graphite. †Mylar is the tradename of poly(ethelene-terephthalate) film, marketed by Du Pont.

  13. Observation of the antimatter helium-4 nucleus.

    Science.gov (United States)

    2011-05-19

    High-energy nuclear collisions create an energy density similar to that of the Universe microseconds after the Big Bang; in both cases, matter and antimatter are formed with comparable abundance. However, the relatively short-lived expansion in nuclear collisions allows antimatter to decouple quickly from matter, and avoid annihilation. Thus, a high-energy accelerator of heavy nuclei provides an efficient means of producing and studying antimatter. The antimatter helium-4 nucleus (4He), also known as the anti-α (α), consists of two antiprotons and two antineutrons (baryon number B = -4). It has not been observed previously, although the α-particle was identified a century ago by Rutherford and is present in cosmic radiation at the ten per cent level. Antimatter nuclei with B Collider (RHIC; ref. 6) in 10(9) recorded gold-on-gold (Au+Au) collisions at centre-of-mass energies of 200 GeV and 62 GeV per nucleon-nucleon pair. The yield is consistent with expectations from thermodynamic and coalescent nucleosynthesis models, providing an indication of the production rate of even heavier antimatter nuclei and a benchmark for possible future observations of 4He in cosmic radiation.

  14. Diffusion Monte Carlo calculation of rate of elastic transmission of a helium vapor beam through a slab of superfluid helium

    Science.gov (United States)

    Lutsyshyn, Y.; Halley, J. W.

    2011-01-01

    We present the results of diffusion Monte Carlo calculations of the elastic transmission of a low-energy beam of helium atoms through a suspended slab of superfluid helium. These calculations represent a significant improvement on variational Monte Carlo methods which were previously used to study this problem. The results are consistent with the existence of a condensate-mediated transmission mechanism, which would result in very fast transmission of pulses through a slab.

  15. Detection of significant differences between absorption spectra of neutral helium and low temperature photoionized helium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bartnik, A.; Wachulak, P.; Fiedorowicz, H.; Fok, T.; Jarocki, R.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)

    2013-11-15

    In this work, spectral investigations of photoionized He plasmas were performed. The photoionized plasmas were created by irradiation of helium stream, with intense pulses from laser-plasma extreme ultraviolet (EUV) source. The EUV source was based on a double-stream Xe/Ne gas-puff target irradiated with 10 ns/10 J Nd:YAG laser pulses. The most intense emission from the source spanned a relatively narrow spectral region below 20 nm, however, spectrally integrated intensity at longer wavelengths was also significant. The EUV radiation was focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulse. The long-wavelength part of the EUV radiation was used for backlighting of the photoionized plasmas to obtain absorption spectra. Both emission and absorption spectra in the EUV range were investigated. Significant differences between absorption spectra acquired for neutral helium and low temperature photoionized plasmas were demonstrated for the first time. Strong increase of intensities and spectral widths of absorption lines, together with a red shift of the K-edge, was shown.

  16. Phonon amplification using evaporation and adsorption of helium

    Energy Technology Data Exchange (ETDEWEB)

    More, T.; Adams, J.S.; Bandler, S.R.; Broueer, S.M.; Lanou, R.E.; Maris, H.J.; Seidel, G.M. [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)

    1996-07-01

    We report the results of experiments designed to investigate the feasibility of amplifying a phonon signal using the evaporation of helium from a superfluid film and its subsequent readsorption onto a helium-free surface. We envision a multistage amplifier in which helium is evaporated from a wafer with a helium film only on one side and then adsorbed onto the film-free surface of a similar wafer. The phonons created by the adsorption reach the film on the opposite side of the wafer and potentially desorb more helium than was evaporated by the first wafer. The amplification would come from the high ratio of the binding energy of a helium atom to a film-free surface relative to the binding energy to the liquid. A number of experiments are reported that investigate the efficiencies of the individual steps of the process. The gain per stage is found to be about 3 for high-energy densities in which multiphonon processes are possible. At low-energy densities, the energy deposited into a film-free wafer is found to be less than the original input energy, with the ratio of output to input energy 0.2. Since in applications requiring amplification the phonon density produced by the adsorption of helium on a wafer will be low, the configuration we have studied{emdash}phonons produced in silicon coated with a saturated {sup 4}He film{emdash}will not result in amplification. However, other configurations might improve the efficiency enough to make an amplifier possible. {copyright} {ital 1996 The American Physical Society.}

  17. Effects of nitrogen and helium on CNS oxygen toxicity in the rat.

    Science.gov (United States)

    Arieli, R; Ertracht, O; Oster, I; Vitenstein, A; Adir, Y

    2005-01-01

    The contribution of inert gases to the risk of central nervous system (CNS) oxygen toxicity is a matter of controversy. Therefore, diving regulations apply strict rules regarding permissible oxygen pressures (Po(2)). We studied the effects of nitrogen and helium (0, 15, 25, 40, 50, and 60%) and different levels of Po(2) (507, 557, 608, and 658 kPa) on the latency to the first electrical discharge (FED) in the EEG in rats, with repeated measurements in each animal. Latency as a function of the nitrogen pressure was not homogeneous for each rat. The prolongation of latency observed in some rats at certain nitrogen pressures, mostly in the range 100 to 500 kPa, was superimposed on the general trend for a reduction in latency as nitrogen pressure increased. This pattern was an individual trait. In contrast with nitrogen, no prolongation of latency to CNS oxygen toxicity was observed with helium, where an increase in helium pressure caused a reduction in latency. This bimodal response and the variation in the response between rats, together with a possible effect of ambient temperature on metabolic rate, may explain the conflicting findings reported in the literature. The difference between the two inert gases may be related to the difference in the narcotic effect of nitrogen. Proof through further research of a correlation between individual sensitivity to nitrogen narcosis and protection by N(2) against CNS oxygen toxicity in rat may lead to a personal O(2) limit in mixed-gas diving based on the diver sensitivity to N(2) narcosis.

  18. Thermal Annealing Behavior of Helium in Ti Films Deposited by Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; HE Zhi-Jiang; LIU Chao-Zhuo; WANG Xu-Fei; SHI Li-Qun

    2012-01-01

    Helium contents of up to 30at.% are prepared in sputter-deposited Ti Silms. Isochronal annealing behaviors of helium including the depth profiles and the evolution of helium bubbles in the fi1ms at different temperatures are examined by ion beam analysis including Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA), as well as thermal helium desorption spectroscopy (THDS). It is found that the energy spreading induced by structural inhomogeneities in the spectra of RBS and ERDA as well as the increment in the width of spectra occurs, which corresponds to the change of stopping cross-section of helium atoms in the Ti 61m due to the change of physical-state of helium in the evolution of helium bubble. The ion beam analysis on the helium evolution is consistent with the THDS measurement. Ion beam technique opens interesting possibilities in the characterizing on the growth of helium bubbles.%Helium contents of up to 30at.% are prepared in sputter-deposited Ti films.Isochronal annealing behaviors of helium including the depth profiles and the evolution of helium bubbles in the films at different temperatures are examined by ion beam analysis including Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA),as well as thermal helium desorption spectroscopy (THDS).It is found that the energy spreading induced by structural inhomogeneities in the spectra of RBS and ERDA as well as the increment in the width of spectra occurs,which corresponds to the change of stopping cross-section of helium atoms in the Ti film due to the change of physical-state of helium in the evolution of helium bubble.The ion beam analysis on the helium evolution is consistent with the THDS measurement.Ion beam technique opens interesting possibilities in the characterizing on the growth of helium bubbles.

  19. Development of a cryogenic flexible pipe for the transfer of liquefied natural gas; Mise au point d'un flexible cryogenique pour le transfert du gaz naturel liquefie

    Energy Technology Data Exchange (ETDEWEB)

    Rigaud, J.; Gerez, J.M.; Dieumegard, C. [Coflexip Stena Offshore, 75 - Paris (France)

    2000-07-01

    For historical reasons, the liquefaction of natural gas is performed with onshore equipments and LNG tanker-ships are loaded and unloaded using rigid articulated arms. When these operations are performed in harbors, the movement of the ship with respect to the pier are relatively limited. Today, several companies aim at liquefying natural gas using floating facilities. The loading of tanker-ships is performed offshore, and thus movements between the ship and the floating facility are enhanced. The use of a flexible pipe can be an interesting alternative solution to the articulated arm. This article describes the state-of-the-art of the LNG flexible technology developed by Coflexip Stena Offshore and the progress of the program of development of a cryogenic flexible: structure, fittings, safety (leaks detection), thermal calculations, optimization of the corrugated hose profile, pressure drops, fatigue tests and service life, materials development, prototype and real tests. (J.S.)

  20. Deployable centralizers

    Energy Technology Data Exchange (ETDEWEB)

    Grubelich, Mark C.; Su, Jiann-Cherng; Knudsen, Steven D.

    2017-02-28

    A centralizer assembly is disclosed that allows for the assembly to be deployed in-situ. The centralizer assembly includes flexible members that can be extended into the well bore in situ by the initiation of a gas generating device. The centralizer assembly can support a large load carrying capability compared to a traditional bow spring with little or no installation drag. Additionally, larger displacements can be produced to centralize an extremely deviated casing.

  1. The Evolutionary Population Synthesis Model for Helium-Enhanced Stellar Populations

    Science.gov (United States)

    Chung, Chul; Yoon, Suk-Jin; Lee, Young-Wook

    2017-01-01

    The discovery of multiple stellar populations in the Milky Way globular clusters has stimulated a great deal of researches on the helium enhanced stellar populations. Here, we present the evolutionary population synthesis models for integrated spectro-photometric evolution of simple stellar populations (SSPs) with varied initial helium abundances. The integrated properties of helium-enhanced SSPs depend on metallicity and age as are the normal-helium SSPs, but the properties vary greatly with the initial helium abundance. We will discuss how helium-enhanced stellar populations explain many interesting observations of globular clusters and their host galaxies.

  2. Theoretical model of the helium zone plate microscope

    Science.gov (United States)

    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

  3. LRO-LAMP Observations of Lunar Exospheric Helium

    Science.gov (United States)

    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

  4. Diffusion and retention of helium in titanium carbide

    Science.gov (United States)

    Agarwal, S.; Trocellier, P.; Vaubaillon, S.; Miro, S.

    2014-05-01

    The knowledge of helium migration in TiC is an important issue due to its possible use as fuel coating in fission reactors and as first wall material coating in fusion reactors. Helium release measurements and diffusion coefficient calculations of helium in polycrystalline TiC have been carried out in the temperature range (1000-1600 °C) for the time period of 2 h. Polished bars of TiC were implanted with 3 MeV 3He+ ions in normal incidence at a dose of 5 × 1020 at./m2 at room temperature. Helium depth profile was measured at each step using the 3He(d, p0)4He nuclear reaction by varying the incident deuteron energy from 900 to 1800 keV. Effective diffusion coefficients vary from 4.20 × 10-18 to 2.59 × 10-17 m2 s-1 and activation energy values obtained are in the range 0.8-2.5 eV. Due to scarce availability of stoichiometric TiC, challenges in this study came from native vacancies present in the samples. The helium distribution and its release were affected by the presence of grain boundaries. He is considered to undergo two distinct populations into the sample and different values of diffusion coefficient have been determined for each population.

  5. Diffusion and retention of helium in titanium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, S., E-mail: shradha.agarwal@cea.fr [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Trocellier, P. [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Vaubaillon, S. [CEA, INSTN, UEPTN, Laboratoire JANNUS, F-91191 Gif sur Yvette (France); Miro, S. [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France)

    2014-05-01

    The knowledge of helium migration in TiC is an important issue due to its possible use as fuel coating in fission reactors and as first wall material coating in fusion reactors. Helium release measurements and diffusion coefficient calculations of helium in polycrystalline TiC have been carried out in the temperature range (1000–1600 °C) for the time period of 2 h. Polished bars of TiC were implanted with 3 MeV {sup 3}He{sup +} ions in normal incidence at a dose of 5 × 10{sup 20} at./m{sup 2} at room temperature. Helium depth profile was measured at each step using the {sup 3}He(d, p{sub 0}){sup 4}He nuclear reaction by varying the incident deuteron energy from 900 to 1800 keV. Effective diffusion coefficients vary from 4.20 × 10{sup −18} to 2.59 × 10{sup −17} m{sup 2} s{sup −1} and activation energy values obtained are in the range 0.8–2.5 eV. Due to scarce availability of stoichiometric TiC, challenges in this study came from native vacancies present in the samples. The helium distribution and its release were affected by the presence of grain boundaries. He is considered to undergo two distinct populations into the sample and different values of diffusion coefficient have been determined for each population.

  6. Helium shells and faint emission lines from slitless flash spectra

    Directory of Open Access Journals (Sweden)

    Cyril Bazin

    2013-05-01

    Full Text Available At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

  7. Analysis of a low-temperature magnetic helium pump

    Science.gov (United States)

    Prenger, Coyne; Stewart, Walter

    In an effort to improve reliability of cryocoolers, concepts involving no moving parts are being investigated. One concept utilizes an Active Magnetic Regenerator, AMR, to produce refrigeration. However, circulation of the helium working fluid is required for operation of the device. Currently available helium pumps have moving parts and; therefore, result in poor reliability. We propose a magnetically driven pump to provide the helium circulation for the AMR. The pump utilizes the magnetocaloric effect to produce an oscillatory helium flow and; has no moving parts. An analytical model has been developed to analyze the pump's performance in conjunction with an AMR operating between 7 and 20 K. At a frequency of 1 Hz a 0.5 liter pump can produce a 0.75 g/s flow rate at 20 K at an operating pressure of 5 atm. At the liquid helium temperature a two-phase version of this pump would perform substantially better than the single-phase version. A design concept has been developed and will be presented along with the model results.

  8. Validation of Helium Inlet Design for ITER Toroidal Field Coil

    CERN Document Server

    Boyer, C; Hamada, K; Foussat, A; Le Rest, M; Mitchell, N; Decool, P; Savary, F; Sgobba, S; Weiss, K-P

    2014-01-01

    The ITER organization has performed design and its validation tests on a helium inlet structure for the ITER Toroidal Field (TF) coil under collaboration with CERN, KIT, and CEA-Cadarache. Detailed structural analysis was performed in order to optimize the weld shape. A fatigue resistant design on the fillet weld between the shell covers and the jacket is an important point on the helium inlet structure. A weld filler material was selected based on tensile test at liquid helium temperature after Nb3Sn reaction heat treatment. To validate the design of the weld joint, fatigue tests at 7 K were performed using heat-treated butt weld samples. A pressure drop measurement of a helium inlet mock-up was performed by using nitrogen gas at room temperature in order to confirm uniform flow distribution and pressure drop characteristic. These tests have validated the helium inlet design. Based on the validation, Japanese and European Union domestic agencies, which have responsibilities of the TF coil procurement, are pr...

  9. Study of helium embrittlement in boron doped EUROFER97 steels

    Science.gov (United States)

    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.

  10. Electronically excited rubidium atom in a helium cluster or film

    Science.gov (United States)

    Leino, Markku; Viel, Alexandra; Zillich, Robert E.

    2008-11-01

    We present theoretical studies of helium droplets and films doped with one electronically excited rubidium atom Rb∗ (P2). Diffusion and path integral Monte Carlo approaches are used to investigate the energetics and the structure of clusters containing up to 14 helium atoms. The surface of large clusters is approximated by a helium film. The nonpair additive potential energy surface is modeled using a diatomic in molecule scheme. Calculations show that the stable structure of Rb∗Hen consists of a seven helium atom ring centered at the rubidium, surrounded by a tirelike second solvation shell. A very different structure is obtained when performing a "vertical Monte Carlo transition." In this approach, a path integral Monte Carlo equilibration starts from the stable configuration of a rubidium atom in the electronic ground state adsorbed to the helium surface after switching to the electronically excited surface. In this case, Rb∗Hen relaxes to a weakly bound metastable state in which Rb∗ sits in a shallow dimple. The interpretation of the results is consistent with the recent experimental observations [G. Auböck et al., Phys. Rev. Lett. 101, 035301 (2008)].

  11. Helium shells and faint emission lines from slitless flash spectra.

    Science.gov (United States)

    Bazin, Cyril; Koutchmy, Serge

    2013-05-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

  12. Numerical simulation of ejected molten metal-nanoparticles liquefied by laser irradiation: Interplay of geometry and dewetting

    CERN Document Server

    Afkhami, S

    2013-01-01

    Metallic nanoparticles, liquefied by fast laser irradiation, go through a rapid change of shape attempting to minimize their surface energy. The resulting nanodrops may be ejected from the substrate when the mechanisms leading to dewetting are sufficiently strong, as in the experiments involving gold nanoparticles [Habenicht et al., Science 309, 2043 (2005)]. We use a direct continuum-level approach to accurately model the process of liquid nanodrop formation and the subsequent ejection from the substrate. Our computations show a significant role of inertial effects and an elaborate interplay of initial geometry and wetting properties: e.g., we can control the direction of ejection by prescribing appropriate initial shape and/or wetting properties. We validate our computations by comparing directly with the experiments specified above involving the length scales measured in hundreds of nanometers, and with molecular dynamics simulations on much shorter scales measured in tens of atomic diameters, as in M. Fue...

  13. Large scale production of carbon nanotube arrays on the sphere surface from liquefied petroleum gas at low cost

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Liquefied petroleum gas (LPG), a cheap industrial material, is used as carbon source to produce carbon nanotube (CNT) arrays on ceramic spherical surface on a large scale in the floating catalyst process. The ceramic spheres provide huge surface area and good mobility, leading to the mass production of CNT arrays continuously. The arrays obtained from the surface are of good alignment, and the purity is as high as 97.5%. With the decrease of the growth temperature, CNTs in the array form with small-diameter of about 13 nm can be obtained. Therefore, with the industrial fuel as carbon source and the ceramic sphere as substrate, CNT arrays can easily be produced on large scale at low cost.

  14. LNG低温管道支架设计%Introduce the Designing for Liquefied Natural Gas Cryogenic Support

    Institute of Scientific and Technical Information of China (English)

    方锦坤

    2012-01-01

    管道支架是用以保持管道稳固和保证管线安全运行的重要组成部分。文章介绍了LNG低温管道支架设计中支架保冷结构和管部设计的要求,以及一种常用的滑动支架结构详图。%Pipe support is a significant part for fixing the pipeline and ensuring the safely operation of pipeline.The paper introduced the requirement for the structure of heat proof and support design in Liquefied Natural Gas cryogenic support,as well as a detail structural drawing of slide support in common use.

  15. Application of RAM Analyses in Liquefied Natural Gas Terminal%RAM分析在LNG接收站中的应用

    Institute of Scientific and Technical Information of China (English)

    赵静

    2011-01-01

    The reliability engineering and its application were summarized.The importance to modern companies and product were emphasized.The application of RAM in liquefied natural gas terminal was introduced, interrelated application case was provided, and improvement suggestions according to the analysis result were recommended.%概述了可靠性工程的发展和应用,阐明了可靠性对现代企业和产品的重要意义.介绍了RAM(可靠性、可用性、可维护性)分析在液化天然气接收站中的应用过程,并且提供了应用案例和改进建议.

  16. Analysis of Influence of Heat Insulation on the Thermal Regime of Storage Tanks with Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Maksimov Vyacheslav I.

    2016-01-01

    Full Text Available Is numerically investigated the process of convective heat transfer in the reservoirs of liquefied natural gas (LNG. The regimes of natural convection in a closed rectangular region with different intensity of heat exchange at the external borders are investigated. Is solved the time-dependent system of energy and Navier-Stokes equations in the dimensionless variables “vorticity – the stream function”. Are obtained distributions of the hydrodynamic parameters and temperatures, that characterize basic regularities of the processes. The special features of the formation of circulation flows are isolated and the analysis of the temperature distribution in the solution region is carried out. Is shown the influence of geometric characteristics and intensity of heat exchange on the outer boundaries of reservoir on the temperature field in the LNG storage.

  17. Guidance on risk analysis and safety implications of a large liquefied natural gas (LNG) spill over water.

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Gerald William; Melof, Brian Matthew; Luketa-Hanlin, Anay Josephine; Hightower, Marion Michael; Covan, John Morgan; Gritzo, Louis Alan; Irwin, Michael James; Kaneshige, Michael Jiro; Morrow, Charles W.

    2004-12-01

    While recognized standards exist for the systematic safety analysis of potential spills or releases from LNG (Liquefied Natural Gas) storage terminals and facilities on land, no equivalent set of standards or guidance exists for the evaluation of the safety or consequences from LNG spills over water. Heightened security awareness and energy surety issues have increased industry's and the public's attention to these activities. The report reviews several existing studies of LNG spills with respect to their assumptions, inputs, models, and experimental data. Based on this review and further analysis, the report provides guidance on the appropriateness of models, assumptions, and risk management to address public safety and property relative to a potential LNG spill over water.

  18. Energy consumption, destruction of exergy and boil off during the process of liquefaction, transport and regasification of liquefied natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Stradioto, Diogo Angelo; Schneider, Paulo Smith [Dept. of Mechanical Engineering. Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)], e-mail: pss@mecanica.ufrgs.br

    2010-07-01

    A supply chain of Liquefied Natural Gas (LNG) is composed by several processes like extraction, purification, liquefaction, storage, transport, regasification and distribution. In all these stages, processes need of energy. The main objective of this work is to quantify the energy consumption, mass loss and exergy destruction occurred throughout the chain. Results show that the process of liquefaction is the largest consumer of energy. Storage and transport by ship are responsible for the bigger mass losses and regasification is the process of larger destruction of exergy. A case study is performed considering a stream of pure methane at the input of a liquefaction plant, and evaluates energy along the chain, ending up at the distribution of NG after its regasification. (author)

  19. Preconditions for the development of land-based infrastructure for liquefied natural gas (LNG / LBG); Foerutsaettningar foer utbyggnad av landbaserad infrastruktur foer flytande gas (LNG/LBG)

    Energy Technology Data Exchange (ETDEWEB)

    Stenkvist, Maria; Paradis, Hanna; Haraldsson, Kristina; Beijer, Ronja; Stensson, Peter (AaF Industry AB(Sweden))

    2011-06-15

    The conversion potential to replace oil in the energy intensive industries and diesel in heavy transport is estimated in the study to 6.8 TWh and 10 TWh per year, respectively. Several alternative fuels compete for this conversion potential. What fuels will take market share depends on several factors such as price, availability of fuel, availability of process technology and vehicles, technology development and possible future technological advances. For liquid methane to compete a new infrastructure is required that in a cost effective manner makes it possible to distribute the liquid methane to the regions where the need is the greatest. With today's distribution system, including truck delivery from import terminals in Nynaeshamn and Fredrikstad, virtually the entire southern Sweden is within reach of LNG deliveries. The study points out three nodes, Gaevle, Sundsvall and Luleaa, which is suitable for distribution of liquid methane to the central and northern Sweden. The three hubs are suitable for freight transfer to trucks as well as rail and shipping. A strategic nationwide network of refueling stations is also proposed, with a total of 18 new stations, in addition to the filling stations in southern and central Sweden that are already planned or in operation. Both the availability and use of liquid methane in Sweden today is limited. Liquid natural gas, LNG (liquefied natural gas), is primarily used as a backup to biogas plants, in a few industries and as supply for a few filling stations for compressed gas. The availability of LNG and also liquid biogas (LBG liquefied biogas), will increase in coming years. In 2011, two new LNG import terminals are put into operation in Nynaeshamn and Fredrikstad in Norway and two additional import terminals are planned in Gothenburg and Lysekil. Furthermore, two production plants for liquid biogas production have started, and four additional plants are planned, which together will produce around 0.5 TWh LBG annually

  20. Preconditions for the development of land-based infrastructure for liquefied natural gas (LNG / LBG); Foerutsaettningar foer utbyggnad av landbaserad infrastruktur foer flytande gas (LNG/LBG)

    Energy Technology Data Exchange (ETDEWEB)

    Stenkvist, Maria; Paradis, Hanna; Haraldsson, Kristina; Beijer, Ronja; Stensson, Peter (AaF Industry AB(Sweden))

    2011-06-15

    The conversion potential to replace oil in the energy intensive industries and diesel in heavy transport is estimated in the study to 6.8 TWh and 10 TWh per year, respectively. Several alternative fuels compete for this conversion potential. What fuels will take market share depends on several factors such as price, availability of fuel, availability of process technology and vehicles, technology development and possible future technological advances. For liquid methane to compete a new infrastructure is required that in a cost effective manner makes it possible to distribute the liquid methane to the regions where the need is the greatest. With today's distribution system, including truck delivery from import terminals in Nynaeshamn and Fredrikstad, virtually the entire southern Sweden is within reach of LNG deliveries. The study points out three nodes, Gaevle, Sundsvall and Luleaa, which is suitable for distribution of liquid methane to the central and northern Sweden. The three hubs are suitable for freight transfer to trucks as well as rail and shipping. A strategic nationwide network of refueling stations is also proposed, with a total of 18 new stations, in addition to the filling stations in southern and central Sweden that are already planned or in operation. Both the availability and use of liquid methane in Sweden today is limited. Liquid natural gas, LNG (liquefied natural gas), is primarily used as a backup to biogas plants, in a few industries and as supply for a few filling stations for compressed gas. The availability of LNG and also liquid biogas (LBG liquefied biogas), will increase in coming years. In 2011, two new LNG import terminals are put into operation in Nynaeshamn and Fredrikstad in Norway and two additional import terminals are planned in Gothenburg and Lysekil. Furthermore, two production plants for liquid biogas production have started, and four additional plants are planned, which together will produce around 0.5 TWh LBG annually

  1. Interactions of satellite-speed helium atoms with satellite-surfaces. 1. Spatial distributions of reflected helium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Liu, S.M.; Rodgers, W.E.; Knuth, E.L.

    1975-06-01

    Interactions of satellite-speed helium atoms with practical satellite surfaces were investigated experimentally, and spatial distributions of satellite-speed helium beams scattered from four different engineering surfaces were measured. The 7000-m/s helium beams were produced using an arc-heated supersonic molecular beam source. The test surfaces included cleaned 6061-T6 aluminum plate, anodized aluminum foil, white paint, and quartz surfaces. Both in-plane (in the plane containing the incident beam and the surface normal) and out-of-plane spatial distributions of reflected helium atoms were measured for six different incidence angles (0, 15, 30, 45, 60, and 75 deg from the surface normal). It was found that a large fraction of the incident helium atoms were scattered back in the vicinity of the incoming beam, particularly in the case of glancing incidence angles. This unexpected scattering feature results perhaps from the gross roughness of these test surfaces. This prominent backscattering could yield drag coefficients which are higher than for surfaces with either forward-lobed or diffusive (cosine) scattering patterns. (auth)

  2. Helium and neon isotopes in deep Pacific Ocean sediments

    Science.gov (United States)

    Nier, A. O.; Schlutter, D. J.; Brownlee, D. E.

    1990-01-01

    Helium and neon concentration measurements, along with isotope ratio determinations, have been made for particles collected in the deep Pacific with a magnetic sled, and they are believed to be of extraterrestrial origin. Analyses were made for samples consisting of composites of many extremely fine particles and for several individual particles large enough to contain sufficient gas for analysis but small enough to escape melting in their passage through the atmosphere. Step-heating was employed to extract the gas. Cosmic-ray spallation products or solar-wind helium and neon, if present, were not abundant enough to account for the isotopic compositions measured. In the case of the samples of magnetic fines, the low temperature extractions provided elemental and isotopic ratios in the general range found for the primordial gas in carbonaceous chondrites and gas-rich meteorites. The isotopic ratios found in the high temperature extractions suggest the presence of solar-flare helium and neon.

  3. Four-Parameter Scheme for Ground Level of Helium Atom

    Institute of Scientific and Technical Information of China (English)

    HU Xian-Quan; XU Jie; MA Yong; ZHENG Rui-Lun

    2006-01-01

    In this paper, the ground state wave function of four parameters is developed and the expression of the ground state level is derived for the helium atom when the radial Schrodinger equation of the helium atom is solved.The ground energy is respectively computed by the optimized algorithms of Matlab 7.0 and the Monte Carlo methods.Furthermore, the ground state wave function is obtained. Compared with the experiment value and the value with the variation calculus in reference, the results of this paper show that in the four-parameter scheme, not only the calculations become more simplified and precise, but also the radial wave function of the helium atom meets the space symmetry automatically in ground state.

  4. Characterizing uniform discharge in atmospheric helium by numerical modelling

    Institute of Scientific and Technical Information of China (English)

    Lü Bo; Wang Xin-Xin; Luo Hai-Yun; Liang Zhuo

    2009-01-01

    One-dimensional fluid model of dielectric barrier discharge (DBD) in helium at atmospheric pressure was estab-lished and the discharge was numerically simulated. It was found that not only the spatial distributions of the internal parameters such as the electric field, the electron density and ion density are similar to those in a low-pressure glow discharge, but also the visually apparent attribute (light emission) is exactly the same as the observable feature of a low-pressure glow discharge. This confirms that the uniform DBD in atmosphcric helium is a glow type discharge. The fact that the thickness of the cathode fall layer is about 0.5 ram, much longer than that of a normal glow dischargc in helium at atmospheric pressure, indicates the discharge being a sub-normal glow discharge close to normal one. The multipulse phenomenon was reproduced in the simulation and a much less complicated explanation for this phenomenon was given.

  5. Financing strategies for lunar energy enterprises: The helium-3 initiative

    Science.gov (United States)

    Schmitt, Harrison H.

    1995-01-01

    Governments presently have little individual or collective interest in financing large scale lunar enterprises, either for science or potential resource utilization. For example, preliminary technical and economic considerations of the return of lunar helium-3 (3He) for terrestrial fusion power plants suggest positive economic and enviromental returns, however, no significant governmental activity has been focused on this or other space related energy options. General analysis of both short and long term returns on investment for a lunar helium-3 enterprise, including considerations of future launch costs, strongly suggests that private financing may be attracted to this endeavor. A privately organized ``catalytic financing'' approach to providing start-up capital for a lunar helium-3 enterprise appears to be worth consideration.

  6. Nonradiative formation of the positron-helium triplet bound state

    Science.gov (United States)

    di Rienzi, Joseph; Drachman, Richard J.

    2007-02-01

    We have previously calculated the cross section for radiative formation of the interesting bound state consisting of a positron bound to helium, where the atomic electrons are in the triplet spin state. That process uses the metastable triplet helium system as target, and, as expected, it has a very small cross section. In this paper we examine a more probable process in which the state of interest is produced in an exchange rearrangement collision between a positronium atom and the singlet helium ground state: Ps+He(Se1)→PsHe+(Se3)+e- . The present calculation is done in the plane-wave Born approximation, using simple initial and final wave functions and compares post and prior forms.

  7. Effect of helium on tensile properties of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.M.; Billone, M.C.; Smith, D.L. [Argonne National Lab., IL (United States)

    1997-08-01

    Tensile properties of V-4Cr-4Ti (Heat BL-47), 3Ti-1Si (BL-45), and V-5Ti (BL-46) alloys after irradiation in a conventional irradiation experiment and in the Dynamic Helium Charging Experiment (DHCE) were reported previously. This paper presents revised tensile properties of these alloys, with a focus on the effects of dynamically generated helium of ductility and work-hardening capability at <500{degrees}C. After conventional irradiation (negligible helium generation) at {approx}427{degrees}C, a 30-kg heat of V-4Cr-4Ti (BL-47) exhibited very low uniform elongation, manifesting a strong susceptibility to loss of work-hardening capability. In contrast, a 15-kg heat of V-3Ti-1Si (BL -45) exhibited relatively high uniform elongation ({approx}4%) during conventional irradiation at {approx}427{degrees}C, showing that the heat is resistant to loss of work-hardening capability.

  8. Two phase coexistence for the hydrogen-helium mixture

    CERN Document Server

    Fantoni, Riccardo

    2015-01-01

    We use our newly constructed quantum Gibbs ensemble Monte Carlo algorithm to perform computer experiments for the two phase coexistence of a hydrogen-helium mixture. Our results are in quantitative agreement with the experimental results of C. M. Sneed, W. B. Streett, R. E. Sonntag, and G. J. Van Wylen. The difference between our results and the experimental ones is in all cases less than 15% relative to the experiment, reducing to less than 5% in the low helium concentration phase. At the gravitational inversion between the vapor and the liquid phase, at low temperatures and high pressures, the quantum effects become relevant. At extremely low temperature and pressure the first component to show superfluidity is the helium in the vapor phase.

  9. An MCMC determination of the primordial helium abundance

    CERN Document Server

    Aver, Erik; Skillman, Evan D

    2011-01-01

    Spectroscopic observations of the chemical abundances in metal-poor H II regions provide an independent method for estimating the primordial helium abundance. H II regions are described by several physical parameters such as electron density, electron temperature, and reddening, in addition to y, the ratio of helium to hydrogen. It had been customary to estimate or determine self-consistently these parameters to calculate y. Frequentist analyses of the parameter space have been shown to be successful in these determinations, and Markov Chain Monte Carlo (MCMC) techniques have proven to be very efficient in sampling this parameter space. Nevertheless, accurate determination of the primordial helium abundance from observations of H II regions is constrained by both systematic and statistical uncertainties. In an attempt to better reduce the latter, and better characterize the former, we apply MCMC methods to the large dataset recently compiled by Izotov, Thuan, & Stasinska (2007). To improve the reliability...

  10. Simulation of Helium Behaviour in Titanium Crystals Using Molecular Dynamics

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; HOU Qing; SUN Tie-Ying; WU Zhong-Cheng; LONG Xing-Gui; WU Xing-Chun; LUO Shun-Zhong

    2006-01-01

    @@ The behaviour of helium in Ti crystals at 300 K has been investigated by means of the molecular dynamics. The study is focused on the influences of He-Ti interaction on the aggregation of helium atoms in the substrate. When a Born-Mayer potential is used to describe the He-Ti interaction, the He atoms are unable to cluster with each other due to the weak bridge barrier that cannot trap the helium atoms, Whereas using a He-Ti potential that is constructed by fitting the ab initio pairwise He-Ti potential, the clustering of He atoms can be observed. The results indicate that suitable He-Ti potential plays an important role in the formation of He clusters in metals.Moreover, it is noted that the shape of the formed He cluster is irregular, and the produced defect prefers to congregating on one side of the He cluster rather than spreading symmetrically around it.

  11. Experience with Dry Running Vacuum Pumps in Helium Service

    Science.gov (United States)

    Arztmann, R.

    2008-03-01

    A process vacuum system for helium using dry running vacuum pumps only was shop tested and installed in a refrigeration plant to serve cavities operating at 2K for a cryogenic storage ring. The paper explains the joint development steps of Busch AG and Linde Kryotechnik AG to use dry running vacuum pumps for helium service at ambient temperature. A roots type booster pump followed by a non lube rotary screw pump provides very good performance in a helium vacuum pump system. Variable frequency drives on both pumps allow to adjust the pump characteristics to a wide range of operating parameters. Operation without friction of sealing elements in the compression space also of the screw pump promises extended maintenance intervals and virtually no wear on the rotors. The current plant operation at Max Plank Institute in Heidelberg, Germany Laboratory will provide additional experience for further applications.

  12. Supersonic jets of hydrogen and helium for laser wakefield acceleration

    CERN Document Server

    Svensson, K.; Wojda, F.; Senje, L.; Burza, M.; Aurand, B.; Genoud, G.; Persson, A.; Wahlström, C.-G.; Lundh, O.

    2016-01-01

    The properties of laser wakefield accelerated electrons in supersonic gas flows of hydrogen and helium are investigated. At identical backing pressure, we find that electron beams emerging from helium show large variations in their spectral and spatial distributions, whereas electron beams accelerated in hydrogen plasmas show a higher degree of reproducibility. In an experimental investigation of the relation between neutral gas density and backing pressure, it is found that the resulting number density for helium is ∼30% higher than for hydrogen at the same backing pressure. The observed differences in electron beam properties between the two gases can thus be explained by differences in plasma electron density. This interpretation is verified by repeating the laser wakefield acceleration experiment using similar plasma electron densities for the two gases, which then yielded electron beams with similar properties.

  13. A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

    CERN Document Server

    Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

    1997-01-01

    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

  14. The Story of Helium and the Birth of Astrophysics

    CERN Document Server

    Nath, Biman B

    2013-01-01

    Biman Nath The Story of Helium and the Birth of Astrophysics Helium was the first element ever discovered by astronomers. Its presence was first indicated in the Sun and not on Earth. Further, its discovery marked the birth of the new science of astrophysics. However, it turns out that the events leading to the discovery of helium have been rather misrepresented in books, journals, and even encyclopedias. The usual story about its joint discovery during a solar eclipse in 1868 by French astronomer Pierre Janssen and late in England by Norman Lockyer, is far from the truth. Janssen never mentioned any new spectral line in his reports. The actual story turns out to be as dramatic as in fiction. This book tells the story without jargon, using the words of the scientists themselves (from their letters and reports), and rescues the real story from the backwaters of history.

  15. Experimental characterization of turbulent superfluid helium

    Science.gov (United States)

    Paoletti, Matthew S.

    Fundamental processes in turbulent superfluid 4He are experimentally characterized by refining a visualization technique recently introduced by Bewley et al.. A mixture of hydrogen and helium gas is injected into the bulk fluid, which produces a distribution of micron-sized hydrogen tracer particles that are visualized and individually tracked allowing for local velocity measurements. Tracer trajectories are complex since some become trapped on the quantized vortices while others flow with the normal fluid. This technique is first applied to study the dynamics of a thermal counterflow. The resulting observations constitute the first direct confirmation of two-fluid motions in He II and provide a quantitative test of the expression for the dependence of the normal fluid velocity, vn, on the applied heat flux, q, derived by L. D. Landau in 1941. Nearly 20,000 individual reconnection events are identified for the first time and used to characterize the dynamics by the minimum separation distance, delta( t), between two reconnecting vortices. Dimensional arguments predict that this separation behaves asymptotically as delta(t) ≈ A(kappa∣t -- t0∣) 1/2, where kappa = h/m is the quantum of circulation. The major finding of the experiments is strong support for this asymptotic form with kappa as the dominant controlling quantity. Nevertheless there are significant event-to-event fluctuations that are equally well fit by two modified expressions: (a) an arbitrary power-law expression delta( t) = B∣t -- t0∣alpha and (b) a correction-factor expression delta(t) = A(kappa∣t -- t 0)1/2 (1 + c∣t -- t0∣). In light of various physical interpretations we regard the correction-factor expression (b), which attributes the observed deviations from the predicted asymptotic form to fluctuations in the local environment and boundary conditions, as best describing the experimental data. The observed dynamics appear statistically time-reversible, suggesting that an effective

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

    Science.gov (United States)

    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.

  17. 76 FR 30362 - Federal Acquisition Regulation; Submission for OMB Review; Acquisition of Helium

    Science.gov (United States)

    2011-05-25

    ... ADMINISTRATION [OMB Control No. 9000-0113; Docket 2011-0079; Sequence 5] Federal Acquisition Regulation; Submission for OMB Review; Acquisition of Helium AGENCY: Department of Defense (DOD), General Services... approved information collection requirement concerning acquisition of helium. Public comments...

  18. An investigation of high fractions of metastable helium atoms

    Institute of Scientific and Technical Information of China (English)

    X.P.Feng(冯贤平); B.W.James

    2003-01-01

    Penning type discharge was adopted to excite helium atoms. It is suitable for generating high densitymetastables at a range from 0.1 mTorr to 0.5 Tort. The highest metastable density of 3.5 × 1010 cm-3was observed at a static gas pressure of 0.5 Torr. The highest fraction of metastables (N21s/NHe) of 10-3in a low gas pressure was obtained. The variation of the magnetic field strength on the discharge doesnot result in a significant density change of the metastable helium atoms. When no magnetic field wasapplied, no discharge took place.

  19. A Neutron Scattering Study of Collective Excitations in Superfluid Helium

    DEFF Research Database (Denmark)

    Graf, E. H.; Minkiewicz, V. J.; Bjerrum Møller, Hans;

    1974-01-01

    Extensive inelastic-neutron-scattering experiments have been performed on superfluid helium over a wide range of energy and momentum transfers. A high-resolution study has been made of the pressure dependence of the single-excitation scattering at the first maximum of the dispersion curve over...... of the multiexcitation scattering was also studied. It is shown that the multiphonon spectrum of a simple Debye solid with the phonon dispersion and single-excitation cross section of superfluid helium qualitatively reproduces these data....

  20. The Erosion of Frozen Argon by Swift Helium Ions

    DEFF Research Database (Denmark)

    Besenbacher, F.; Bøttiger, Jørgen; Graversen, O.

    1981-01-01

    The temperature, energy, and thickness dependence of the erosion rates of frozen argon films when irradiated with 0.1–3 MeV helium ions have been measured. The erosion yields Y are much too high to be explained by the concentional collisional cascade-sputtering theory and are furthermore unequivo......The temperature, energy, and thickness dependence of the erosion rates of frozen argon films when irradiated with 0.1–3 MeV helium ions have been measured. The erosion yields Y are much too high to be explained by the concentional collisional cascade-sputtering theory and are furthermore...

  1. Radioactive core ions of microclusters, ``snowballs`` in superfluid helium

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, N. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Shimoda, T. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Fujita, Y. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Miyatake, H. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Mizoi, Y. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Kobayashi, H. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Sasaki, M. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Shirakura, T. [Osaka Univ., Toyonaka (Japan). Dept. of Physics; Itahashi, T. [Research Center for Nuclear Physics, Osaka Univ., Ibaraki (Japan); Mitsuoka, S. [Research Center for Nuclear Physics, Osaka Univ., Ibaraki (Japan); Matsukawa, T. [Naruto Univ. of Education, Tokushima (Japan); Ikeda, N. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Morinobu, S. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Hinde, D.J. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences; Asahi, K. [Tokyo Inst. of Tech. (Japan). Dept. of Physics; Ueno, H. [Tokyo Inst. of Tech. (Japan). Dept. of Physics; Izumi, H. [Tokyo Inst. of Tech. (Japan). Dept. of Physics

    1996-12-01

    Short-lived beta-ray emitters, {sup 12}B, sustaining nuclear spin polarization were introduced into superfluid helium. The nuclear polarization of {sup 12}B was observed via measurement of beta-ray asymmetry. It was found that the nuclear polarization was preserved throughout the lifetime of {sup 12}B (20.3 ms). This suggests that the ``snowball``, an aggregation of helium atoms produced around an alien ion, constitutes a suitable milieu for freezing-out the nuclear spin of the core ion and that most likely the solidification takes place at the interior of the aggregation. (orig.).

  2. A design for a pinhole scanning helium microscope

    Energy Technology Data Exchange (ETDEWEB)

    Barr, M.; Fahy, A. [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia); Jardine, A.; Ellis, J.; Ward, D. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); MacLaren, D.A. [Dept. of Physics, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Allison, W. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Dastoor, P.C., E-mail: Paul.Dastoor@newcastle.edu.au [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia)

    2014-12-01

    We present a simplified design for a scanning helium microscope (SHeM) which utilises almost entirely off the shelf components. The SHeM produces images by detecting scattered neutral helium atoms from a surface, forming an entirely surface sensitive and non-destructive imaging technique. This particular prototype instrument avoids the complexities of existing neutral atom optics by replacing them with an aperture in the form of an ion beam milled pinhole, resulting in a resolution of around 5 microns. Using the images so far produced, an initial investigation of topological contrast has been performed.

  3. Operation of an opamp at liquid helium temperature.

    Science.gov (United States)

    Ng, K.-W.

    1994-02-01

    The stray capacitance between long wires in a cryogenics systems will slow down measurement rate, and also introduce unnecessary noise pick up. It is necessary to install the preamplifier as close to the signal source as possible to diminish the capacitive coupling effects. The most commonly used semiconducting device for this purpose is the MOSFET, which can function at liquid helium temperatures. Under special operation procedures, an all MOSFET operational amplifier can also be operated at liquid helium temperature. The use of opamp will simplify the construction of more complicated circuitry for low temperature applications.

  4. Dynamic simulator of helium refrigeration system; Hemiumu reitoki doteki shumyureta

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, H.; Mori, M.; Miyake, A. [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan)

    1999-06-07

    The helium refrigerator has various operation modes. Therefore, it is insufficient for developing the refrigerating machine only by the static simulator, which simulates only one design point. It is necessary to carry out the design, which can deal with the change of the operation mode and construction of the appropriate controllability of the system. The construction of the dynamic simulator is required in the reason. This time, the heat exchanger in the helium refrigerator cool-down was unsteadily analyzed, and it was compared with the measured value. (NEDO)

  5. Detectability of Light Dark Matter with Superfluid Helium.

    Science.gov (United States)

    Schutz, Katelin; Zurek, Kathryn M

    2016-09-16

    We show that a two-excitation process in superfluid helium, combined with sensitivity to meV energy depositions, can probe dark matter down to the ∼keV warm dark matter mass limit. This mass reach is 3 orders of magnitude below what can be probed with ordinary nuclear recoils in helium at the same energy resolution. For dark matter lighter than ∼100  keV, the kinematics of the process requires the two athermal excitations to have nearly equal and opposite momentum, potentially providing a built-in coincidence mechanism for controlling backgrounds.

  6. Detection and Imaging of He_2 Molecules in Superfluid Helium

    CERN Document Server

    Rellergert, W G; Garvan, A; Hanson, J C; Lippincott, W H; Nikkel, J A; McKinsey, D N

    2007-01-01

    We present data supporting our previous proposal [1] for using cycling transitions to detect and image metastable He_2 triplet molecules in superfluid helium. We demonstrate that limitations on the cycling efficiency due to the vibrational structure of the molecule can be mitigated by the use of repumping lasers. Images of the molecules obtained using the method are also shown. This technique gives rise to a new kind of ionizing radiation detector. The use of He_2 triplet molecules as tracer particles in the superfluid promises to be a powerful tool for visualization of both quantum [2-4] and classical [5] turbulence in liquid helium.

  7. Transmission Electron Microscopy Characterization of Helium Bubbles in Aged Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, A J; Wall, M A; Zocco, T G; Blobaum, K M

    2004-11-02

    The self-irradiation damage generated by alpha decay of plutonium results in the formation of lattice defects, helium, and uranium atoms. Over time, microstructural evolution resulting from the self-irradiation may influence the physical and mechanical properties of the material. In order to assess microstructural changes, we have developed and applied procedures for the specimen preparation, handling, and transmission electron microscopy characterization of Pu alloys. These transmission electron microscopy investigations of Pu-Ga alloys ranging in age up to 42-years old reveal the presence of nanometer-sized helium bubbles. The number density of bubbles and the average size have been determined for eight different aged materials.

  8. Nanocrystalline silicon prepared at high growth rate using helium dilution

    Indian Academy of Sciences (India)

    Koyel Bhattacharya; Debajyoti Das

    2008-06-01

    Growth and optimization of the nanocrystalline silicon (nc-Si : H) films have been studied by varying the electrical power applied to the helium diluted silane plasma in RF glow discharge. Wide optical gap and conducting intrinsic nanocrystalline silicon network of controlled crystalline volume fraction and oriented crystallographic lattice planes have been obtained at a reasonably high growth rate from helium diluted silane plasma, without using hydrogen. Improving crystallinity in the network comprising ∼ 10 nm Si-nanocrystallites and contributing optical gap widening, conductivity ascending and that obtained during simultaneous escalation of the deposition rate, promises significant technological impact.

  9. Methods of Helium Injection and Removal for Heat Transfer Augmentation

    Science.gov (United States)

    Haight, Harlan; Kegley, Jeff; Bourdreaux, Meghan

    2008-01-01

    While augmentation of heat transfer from a test article by helium gas at low pressures is well known, the method is rarely employed during space simulation testing because the test objectives usually involve simulation of an orbital thermal environment. Test objectives of cryogenic optical testing at Marshall Space Flight Center's X-ray Cryogenic Facility (XRCF) have typically not been constrained by orbital environment parameters. As a result, several methods of helium injection have been utilized at the XRCF since 1999 to decrease thermal transition times. A brief synopsis of these injection (and removal) methods including will be presented.

  10. Sodium dopants in helium clusters: Structure, equilibrium and submersion kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, F. [Laboratoire Interdisciplinaire de Physique, Rue de La Piscine, Campus Saint Martin d’Hères, 38000 Grenoble (France)

    2015-12-31

    Alkali impurities bind to helium nanodroplets very differently depending on their size and charge state, large neutral or charged dopants being wetted by the droplet whereas small neutral impurities prefer to reside aside. Using various computational modeling tools such as quantum Monte Carlo and path-integral molecular dynamics simulations, we have revisited some aspects of the physical chemistry of helium droplets interacting with sodium impurities, including the onset of snowball formation in presence of many-body polarization forces, the transition from non-wetted to wetted behavior in larger sodium clusters, and the kinetics of submersion of small dopants after sudden ionization.

  11. Inelastic collisions of excited helium atoms with normal rubidium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Blagoev, K.B.; Kasyanenko, S.V.; Krauze, U.; Tolmachev, Y.A.

    1986-05-01

    The afterglow of helium lines in a helium--rubidium mixture excited by a pulsed electron beam has been studied. The effective quenching probabilities at different concentrations of rubidium have been measured, and the rate constants and effective quenching cross sections have been determined. An analysis of possible mechanisms of an inelastic collision is given. A major role of the ionic term in the interaction of the particles during collisions is indicated. The experimental values of the cross sections are compared with the results of a calculation in different approximations.

  12. Superelastic rescattering in single ionization of helium in strong laser fields

    Science.gov (United States)

    Li, Zhi-Chao; Jaron-Becker, Agnieszka; He, Feng

    2016-10-01

    Rescattering is a central process in ultrafast physics, in which an electron, freed from an atom and accelerated by a laser field, loses its energy by producing high-order harmonics or multiple ionization. Here, taking helium as a prototypical atom, we demonstrate numerically superelastic rescattering in single ionization of an atom. In this scenario, the absorption of a high-energy extreme ultraviolet photon leads to emission of one electron and excitation of the second one into its first excited state, forming He+*. A time-delayed midinfrared laser pulse accelerates the freed electron, drives it back to the He+*, and induces the transition of the bound electron to the ground state of the ion. Identification of the superelastic rescattering process in the photoelectron momentum spectra provides a means to determine the photoelectron momentum at the time of rescattering without using any information of the time-delayed probe laser pulse.

  13. Membrane Thickness Dependence of Nanopore Formation with a Focused Helium Ion Beam

    Directory of Open Access Journals (Sweden)

    Furat Sawafta

    2014-05-01

    Full Text Available Solid-state nanopores are emerging as a valuable tool for the detection and characterization of individual biomolecules. Central to their success is the realization of fabrication strategies that are both rapid and flexible in their ability to achieve diverse device dimensions. In this paper, we demonstrate the membrane thickness dependence of solid-state nanopore formation with a focused helium ion beam. We vary membrane thickness in situ and show that the rate of pore expansion follows a reproducible trend under all investigated membrane conditions. We show that this trend shifts to lower ion dose for thin membranes in a manner that can be described quantitatively, allowing devices of arbitrary dimension to be realized. Finally, we demonstrate that thin, small-diameter nanopores formed with our approach can be utilized for high signal-to-noise ratio resistive pulse sensing of DNA.

  14. 43 CFR 16.1 - Agreements to dispose of helium in natural gas.

    Science.gov (United States)

    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...

  15. Calculations of Electron Structure of Endohedrally Confined Helium Atom with B-Spline Type Functions

    Institute of Scientific and Technical Information of China (English)

    QIAO HaoXue; SHI TingYun; LI BaiWen

    2002-01-01

    The B-spline basis set method is used to study the properties of helium confined endohedrally at thegeometrical centre of a fullerene. The boundary conditions of the wavefunctions can be simply satisfied with thismethod. From our results, the phenomenon of "mirror collapse" is found in the case of confining helium. The interestingbehaviors of confining helium are also discussed.

  16. Sputtering of solid nitrogen by keV helium ions

    DEFF Research Database (Denmark)

    Ellegaard, O.; Schou, Jørgen; Sørensen, H.;

    1993-01-01

    Solid nitrogen has become a standard material among the frozen molecular gases for electronic sputtering. We have combined measurements of sputtering yields and energy spectra from nitrogen bombarded by 4-10 keV helium ions. The data show that the erosion is electronic rather than knockon...

  17. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    Science.gov (United States)

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  18. Pulsations in Hydrogen Burning Low Mass Helium White Dwarfs

    CERN Document Server

    Steinfadt, Justin D R; Arras, Phil

    2010-01-01

    Helium core white dwarfs (WDs) with mass M < 0.20 M_sun undergo several Gyrs of stable hydrogen burning as they evolve. We show that in a certain range of WD and hydrogen envelope masses, these WDs may exhibit g-mode pulsations similar to their passively cooling, more massive carbon/oxygen core counterparts, the ZZ Cetis. Our models with stably burning hydrogen envelopes on helium cores yield g-mode periods and period spacings longer than the canonical ZZ Cetis by nearly a factor of two. We show that core composition and structure can be probed using seismology since the g-mode eigenfunctions predominantly reside in the helium core. Though we have not carried out a fully nonadiabatic stability analysis, the scaling of the thermal time in the convective zone with surface gravity highlights several low mass helium WDs that should be observed in search of pulsations: NLTT 11748, SDSS J0822+2753, and the companion to PSR J1012+5307. Seismological studies of these He core WDs may prove especially fruitful, as t...

  19. Bose-Einstein condensation in helium white dwarf stars. I

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera, M.E. [Faculty of Astronomy and Geophysics, University of La Plata, Paseo del Bosque s.n., La Plata (Argentina); Department of Physics, University of La Plata, c.c. 67 1900, La Plata (Argentina); Civitarese, O., E-mail: osvaldo.civitarese@fisica.unlp.edu.a [Department of Physics, University of La Plata, c.c. 67 1900, La Plata (Argentina); Benvenuto, O.G.; De Vito, M.A. [Faculty of Astronomy and Geophysics, University of La Plata, Paseo del Bosque s.n., La Plata (Argentina); Instituto de Astrofisica La Plata, CCT (Argentina)

    2010-01-18

    The formation of a Bose-Einstein condensate in the interior of helium white dwarfs stars is discussed. Following the proposal made by Gabadadze and Rosen, we have explored the consequences of such a mechanism by calculating the cooling time of the stars. We have found that it is shorter than the value predicted by the standard model.

  20. US Congress considers bill to relieve helium shortage

    Science.gov (United States)

    Gwynne, Peter

    2013-04-01

    A bill to alleviate the threat of a significant shortage of helium was set to be debated in the US House of Representatives as Physics World went to press with the House's Natural Resources Committee putting the finished touches to the motion.

  1. Direct Three-body Triple-$\\alpha$ in Helium Novae

    CERN Document Server

    Connolly, Ryan; Brown, Edward F

    2016-01-01

    In AM CVn binaries, a white dwarf primary accretes material from a helium-rich white dwarf or stellar companion. The unstable ignition of nuclear burning via the $3\\alpha$ reaction in an accumulated helium layer powers a thermonuclear runaway near accretion rates $\\dot{M} \\lesssim 10^{-6} \\, \\mathrm{M_{\\odot} \\ yr^{-1}}$ that may be observed as helium nova or .Ia supernova. Helium burning in the primary's envelope at temperatures $T \\lesssim 10^{8} \\, \\mathrm{K}$ may proceed via the direct three-body fusion of $\\alpha$-particles. Here we show that the direct three-body rate by Nguyen et al. (2012) -- which is reduced relative to the extrapolated resonant rate at temperatures $T \\gtrsim 5 \\times 10^{7} \\, \\mathrm{K}$ -- results in novae with longer recurrence times and larger ignition masses. By contrast, we find that the enhancement in the direct three-body rate at temperatures below $T \\lesssim 5 \\times 10^{7} \\, \\mathrm{K}$ does not result in significant differences in nova outburst properties. The most mas...

  2. A catalogue of helium abundance indicators from globular cluster photometry

    Science.gov (United States)

    Sandquist, Eric L.

    2000-04-01

    We present a survey of helium abundance indicators derived from a comprehensive study of globular cluster photometry in the literature. For each of the three indicators used, we conduct a thorough error analysis, and identify systematic errors in the computational procedures. For the population ratio RNHBNRGB, we find that there is no evidence of a trend with metallicity, although there appears to be real scatter in the values derived. Although this indicator is the one best able to provide useful absolute helium abundances, the mean value is Y~0.20, indicating the probable presence of additional systematic error. For the magnitude difference from the horizontal branch to the main sequence Δ and the RR Lyrae mass-luminosity exponent A, it is only possible to determine relative helium abundances reliably. This is due to continuing uncertainties in the absolute metallicity scale for Δ, and uncertainty in the RR Lyrae temperature scale for A. Both indicators imply that the helium abundance is approximately constant as a function of [Fe/H]. According to the A indicator, both Oosterhoff I and II group clusters have constant values independent of [Fe/H] and horizontal branch type. In addition, the two groups have slopes dlog/d[Fe/H] that are consistent with each other, but significantly smaller than the slope for the combined sample.

  3. Hot-wire anemometry in hypersonic helium flow

    Science.gov (United States)

    Wagner, R. D.; Weinstein, L. M.

    1974-01-01

    Hot-wire anemometry techniques are described that have been developed and used for hypersonic-helium-flow studies. The short run time available dictated certain innovations in applying conventional hot-wire techniques. Some examples are given to show the application of the techniques used. Modifications to conventional equipment are described, including probe modifications and probe heating controls.

  4. Transport and extraction of radioactive ions stopped in superfluid helium

    NARCIS (Netherlands)

    Huang, WX; Dendooven, P; Gloos, K; Takahashi, N; Arutyunov, K; Pekola, JP; Aysto, J

    2003-01-01

    A new approach to convert a high energy beam to a low energy one, which is essential for the next generation radioactive ion beam facilities, has been proposed and tested at Jyvaskyla, Finland. An open Ra-223 alpha-decay-recoil source has been used to produce radioactive ions in superfluid helium. T

  5. Modes of Homogeneous Barrier Discharge at Atmospheric Pressure in Helium

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-Hui; WANG De-Zhen

    2004-01-01

    @@ The discharge modes of a homogeneous barrier discharge at atmospheric pressure in helium are investigated with a one-dimensional fluid model It is found that, either in single peak discharge or in multipeak discharge, there are two discharge modes: glow and Townsend modes. The structure and features of the two modes are compared.The conditions forming the two modes are discussed.

  6. Measurement of strong interaction effects in antiprotonic helium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J.D.; Gorringe, T.P.; Lowe, J.; Nelson, J.M.; Playfer, S.M.; Pyle, G.J.; Squier, G.T.A. (Birmingham Univ. (UK). Dept. of Physics); Baker, C.A.; Batty, C.J.; Clark, S.A.

    1984-09-27

    The strong interaction shift and width for the 2 p level and the width for the 3d level have been measured for antiprotonic helium atoms. The results are compared with optical model calculations. The possible existence of strongly bound antiproton states in nuclei is discussed.

  7. Helium effects on tungsten surface morphology and deuterium retention

    NARCIS (Netherlands)

    Ueda, Y.; H. Y. Peng,; H. T. Lee,; N. Ohno,; S. Kajita,; Yoshida, N.; Doerner, R.; De Temmerman, G.; V. Alimov,; G. Wright,

    2013-01-01

    Recent experimental results on tungsten surface morphology, especially nano-structure (fuzz), induced by helium plasma exposure at temperatures between 1000 K and 2000 K are reviewed. This structure was firstly reported in 2006. In this review, most of experimental results reported

  8. Solvation of Na+, K+, and their dimers in helium.

    Science.gov (United States)

    An der Lan, Lukas; Bartl, Peter; Leidlmair, Christian; Jochum, Roland; Denifl, Stephan; Echt, Olof; Scheier, Paul

    2012-04-02

    Helium atoms bind strongly to alkali cations which, when embedded in liquid helium, form so-called snowballs. Calculations suggest that helium atoms in the first solvation layer of these snowballs form rigid structures and that their number (n) is well defined, especially for the lighter alkalis. However, experiments have so far failed to accurately determine values of n. We present high-resolution mass spectra of Na(+)He(n), K(+)He(n), Na(2)(+)He(n) and K(2)(+)He(n), formed by electron ionization of doped helium droplets; the data allow for a critical comparison with several theoretical studies. For sodium and potassium monomers the spectra indicate that the value of n is slightly smaller than calculated. Na(2)(+)He(n) displays two distinct anomalies at n=2 and n=6, in agreement with theory; dissociation energies derived from experiment closely track theoretical values. K(2)(+)He(n) distributions are fairly featureless, which also agrees with predictions.

  9. Microstructure of helium-implanted Nimonic PE16

    Energy Technology Data Exchange (ETDEWEB)

    Czyrska-Filemonowicz, A.; Gadalla, A.A.; Kesternich, W.; Weckermann, B.

    1987-09-01

    Transmission electron microsocpy has been used to investigate the microstructure in Nimonic PE16 after room temperature a-implementation followed by subsequent annealing. Helium bubble formation in the matrix, at dislocations, at grain boundaries and at precipitates of ..gamma..', M/sub 23/C/sub 6/, and MC type has been studied.

  10. Experimental studies of amplification using evaporation and adsorption of helium

    Energy Technology Data Exchange (ETDEWEB)

    More, T. [Brown Univ., Providence, RI (United States). Dept. of Physics; Adams, J.S. [Brown Univ., Providence, RI (United States). Dept. of Physics; Bandler, S.R. [Brown Univ., Providence, RI (United States). Dept. of Physics; Brouer, S.M. [Brown Univ., Providence, RI (United States). Dept. of Physics; Lanou, R.E. [Brown Univ., Providence, RI (United States). Dept. of Physics; Maris, H.J. [Brown Univ., Providence, RI (United States). Dept. of Physics; Seidel, G.M. [Brown Univ., Providence, RI (United States). Dept. of Physics

    1996-02-11

    The design of a phonon amplifier based on the evaporation of helium atoms from a superfluid film and their adsorption onto a bare solid surface is discussed. Experimental results indicate that substantial improvement in efficiency is required to be able to construct such an amplifier. A possible modification to achieve this improvement is considered. (orig.).

  11. Projected performance of a large superfluid helium solar neutrino detector

    Energy Technology Data Exchange (ETDEWEB)

    Bandler, S.R.; Enss, C.; Goldhaber, G.; Lanou, R.E.; Maris, H.J.; More, T.; Porter, F.S.; Seidel, G.M. (Brown Univ., Providence, RI (United States))

    1993-11-01

    Based upon experiments carried out using radioactive sources to investigate the particle detection properties of superfluid helium the authors project a configuration for and the response of a full scale detector for solar neutrinos employing the roton/quantum evaporation technique.

  12. Apparatus to measure low level helium for neutron dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, Shuji; Takao, Yoshiyuki; Muramasu, Masatomo; Hida, Tomoya; Sou, Hirofumi; Nakashima, Hideki [Kyushu Univ., Fukuoka (Japan); Kanda, Yukinori

    1998-03-01

    An apparatus to measure low level helium in a solid sample for neutron dosimetry in the practical use such as area monitoring in the long-term and reactor surveillance was reported. In our previous work, the helium atoms measurement system (HAMS) was developed. A sample was evaporated in the furnace and the released gas from the sample was analyzed with the mass spectrometer of the system to determine the amount of helium contained in it. The system has been improved to advance the lower helium measurement limit in a solid sample for its application to an area monitoring system. The mass of a solid is up to 100mg. Two important points should be considered to advance the lower limit. One was to produce a high quality vacuum in the system chamber for suppressing background gases during the sample measurement. The other important point was to detect very small output from the mass spectrometer. A pulse counting system was used to get high sensitivity in the mass 4 analyzing. (author)

  13. Field Ionization detection of supersonic helium atom beams

    Science.gov (United States)

    Doak, R. B.

    2003-10-01

    Field ionization detectors (FID) may offer near-unity detection efficiency and nanoscale spatial resolution. To date, FID detection of molecular beams has been limited to effusive beams of broad Maxwellian velocity distributions. We report FID measurements on monoenergetic helium beams, including intensity measurements and time-of-flight measurements. The FID tips were carefully prepared and characterized in a field ionization microscope prior to use. With the supersonic helium beam we find a much smaller effective detection area ( 50 sq. nm) than was reported in the effusive helium beam experiments ( 200,000 sq. nm). This suggests that the FID ionization yield depends strongly on energy loss by the impinging atom during its initial collision with the FID surface: Our thermal energy, monoenergetic helium beam atoms likely lose little or no energy upon scattering from the clean tungsten FID surface, allowing the scattered atoms to escape the FID polarization field and therby reducing the ionization yield. To improve signal levels, inelastic scattering might be enhanced by use of lower beam velocities (present in the tails of a Maxwellian) or by adsorbing an overlayer on the FID tip (present at cryogenic tip temperatures). These factors likely explain the higher detection yields measured in the effusive beam experiments.

  14. Impulsive Laser Induced Alignment of Molecules Dissolved in Helium Nanodroplets

    DEFF Research Database (Denmark)

    Pentlehner, Dominik; H. Nielsen, Jens; Slenczka, Alkwin

    2013-01-01

    We show that a 450 fs nonresonant, moderately intense, linearly polarized laser pulse can induce field-free molecular axis alignment of methyliodide (CH3I) molecules dissolved in a helium nanodroplet. Time-resolved measurements reveal rotational dynamics much slower than that of isolated molecule...

  15. Numerical simulation of losses along a natural circulation helium loop

    Science.gov (United States)

    Knížat, Branislav; Urban, František; Mlkvik, Marek; RidzoÅ, František; Olšiak, Róbert

    2016-06-01

    A natural circulation helium loop appears to be a perspective passive method of a nuclear reactor cooling. When designing this device, it is important to analyze the mechanism of an internal flow. The flow of helium in the loop is set in motion due to a difference of hydrostatic pressures between cold and hot branch. Steady flow at a requested flow rate occurs when the buoyancy force is adjusted to resistances against the flow. Considering the fact that the buoyancy force is proportional to a difference of temperatures in both branches, it is important to estimate the losses correctly in the process of design. The paper deals with the calculation of losses in branches of the natural circulation helium loop by methods of CFD. The results of calculations are an important basis for the hydraulic design of both exchangers (heater and cooler). The analysis was carried out for the existing model of a helium loop of the height 10 m and nominal heat power 250 kW.

  16. Suicidal asphyxiation by using helium – two case reports

    Directory of Open Access Journals (Sweden)

    Anna Smędra

    2015-05-01

    Full Text Available Helium is one of inert gases causing physical asphyxiation, whose excess content in the breathing atmosphere reduces the partial pressure of oxygen and may be fatal after short-term exposure. When breathing a mixture of an inert gas (helium, nitrogen, argon with a small amount of oxygen, with the possibility of exhaling carbon dioxide, no warning signs characteristic of suffocation are perceived by the subject. Freedom from discomfort and pain, effectiveness, rapid effect and relatively easy availability of required accessories have resulted in the use of inert gases for suicidal purposes. The paper reports two cases of suicide committed by using a special kit consisting of the so-called “suicide bag” (or “exit bag” filled with helium supplied through a plastic tube. In both cases, examination of the sites where the corpses were found and analysis of collected material allowed to establish that before their death the subjects had searched the Internet for instructions on how to commit suicide using helium. Due to the advanced putrefaction process, the autopsies failed to determine the causes of their death unequivocally. However, the circumstances surrounding the deaths suggested rapid asphyxiation as a result of oxygen deficiency in the breathing mixture. Since in cases of the type discussed here the cause of death cannot generally be established by autopsy, knowledge of the circumstances of disclosure of the corpse, as well as examination of the cadaver and the death scene is of utmost importance.

  17. 43 CFR 16.2 - Applications for helium disposition agreements.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Applications for helium disposition agreements. 16.2 Section 16.2 Public Lands: Interior Office of the Secretary of the Interior CONSERVATION OF... lost to Federal ownership or use, and to evaluate the suitability of the proposal....

  18. Resonances of the helium atom in a strong magnetic field

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Al-Hujaj, Omar-Alexander; Schmelcher, Peter

    2007-01-01

    We present an investigation of the resonances of a doubly excited helium atom in a strong magnetic field covering the regime B=0–100  a.u. A full-interaction approach which is based on an anisotropic Gaussian basis set of one-particle functions being nonlinearly optimized for each field strength...

  19. The Helium Atom and Isoelectronic Ions in Two Dimensions

    Science.gov (United States)

    Patil, S. H.

    2008-01-01

    The energy levels of the helium atom and isoelectronic ions in two dimensions are considered. The difficulties encountered in the analytical evaluation of the perturbative and variational expressions for the ground state, promote an interesting factorization of the inter-electronic interaction, leading to simple expressions for the energy. This…

  20. Stopping Power of Solid Argon for Helium Ions

    DEFF Research Database (Denmark)

    Besenbacher, F.; Bøttiger, Jørgen; Grauersen, O.

    1981-01-01

    By means of the Rutherford-backscattering method, the stopping cross section of solid argon has been measured for 0.5–3 MeV helium ions to an accuracy of not, vert, similar3%. The results agree within the experimental accuracies with our earlier measurements for gaseous argon over the energy region...