Development of a large lithium coolant system for operation under vacuum

International Nuclear Information System (INIS)

Kolowith, R.; Schwartz, K.E.; Meadows, G.E.; Berg, J.D.

1983-11-01

Argon and vacuum systems for the Experimental Lithium System (ELS) were tested to demonstrate vacuum-break capability, vacuum pumping performance, and vacuum sensor compatibility with a hostile liquid metal vapor/aerosol environment. Mechanical, diffusion and cryogenic vacuum pumps were evaluated. High-vacuum levels in the 10 -3 Pa range were achieved over a 270 0 C flowing lithium system. Ionization, thermal conductivity, capacitance manometer, and compound-type pressure sensors were evaluated to determine the effects of this potentially deleterious environment. Screening elbows were evaluated as pressure sensor protective devices. A dual-purpose vacuum-level/nitrogen partial-pressure sensor was evaluated as a means of detecting air in-leakage. Several types of static mechanical vacuum seals were also evaluated. Measurements of the vapor/aerosol generation were made at several system locations and operating conditions

Distribution of a vacuum charge near supercharged nuclei

International Nuclear Information System (INIS)

Migdal, A.B.; Popov, V.S.; Voskresenskij, D.N.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Teoreticheskoj i Ehksperimental'noj Fiziki)

1977-01-01

The distribution of a vacuum charge near super-critical nuclei (Ze 2 > > 1) is found. The calculation is performed in the Thomas - Fermi approximation extended to the relativistic case. The characteristic parameter in the present problem is Ze 3 approximately Z/1600. For Ze 3 approximately 1 the total charge of the vacuum shell becomes comparable to the nuclear charge Z. The relativistic Thomas - Fermi equation for the vacuum shell of a supercritical atom is solved analytically for two extreme cases, Ze 3 3 > > 1. In the intermediate region, Ze 3 approximately 1, the equation is solved numerically. The Thomas - Fermi equation for a neutral atom (in which not only the vacuum but external electron shells as well are filled up) and also the equation in which allowance is made for exchange and correlation corrections (relativistic generalization of the Thomas -Fermi - Dirac equation) are also considered

A design chart for long vacuum pipes and shells

International Nuclear Information System (INIS)

Krempetz, K.; Grimson, J.; Kelly, P.

1986-01-01

This paper presents a design chart to aid designers in the selection of a wall thickness for long cylindrical shells having atmospheric pressure outside the shell and a pressure less than atmospheric inside the shell. The chart indicates a conservative value for the minimum wall thickness for a given shell diameter and material when the shell is completely evacuated

Spent Nuclear Fuel (SNF) Project Cold Vacuum Drying (CVD) Facility Operations Manual

Energy Technology Data Exchange (ETDEWEB)

IRWIN, J.J.

2000-02-03

This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of the Processing Systems (Garvin 1998) and, the HNF-SD-SNF-DRD-002, 1997, Cold Vacuum Drying Facility Design Requirements, Rev. 3a. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence, and has been developed for the spent nuclear fuel project (SNFP) Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved.

Spent Nuclear Fuel (SNF) Cold Vacuum Drying (CVD) Facility Operations Manual; FINAL

International Nuclear Information System (INIS)

IRWIN, J.J.

1999-01-01

This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-553, Spent Nuclear Fuel Project Final Safety Analysis Report Annex B-Cold Vacuum Drying Facility. The HNF-SD-SNF-DRD-002, 1999, Cold Vacuum Drying Facility Design Requirements, Rev. 4, and the CVDF Final Design Report. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence and references to the CVDF System Design Descriptions (SDDs). This manual has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

Spent Nuclear Fuel (SNF) Project Cold Vacuum Drying (CVD) Facility Operations Manual

International Nuclear Information System (INIS)

IRWIN, J.J.

2000-01-01

This document provides the Operations Manual for the Cold Vacuum Drying Facility (CVDF). The Manual was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of the Processing Systems (Garvin 1998) and, the HNF-SD-SNF-DRD-002, 1997, Cold Vacuum Drying Facility Design Requirements, Rev. 3a. The Operations Manual contains general descriptions of all the process, safety and facility systems in the CVDF, a general CVD operations sequence, and has been developed for the spent nuclear fuel project (SNFP) Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

The proposal of recommendations for the operation of vacuum sewerage

Science.gov (United States)

Mazák, J.; Dvorský, T.; Václavík, V.; Zajac, R.; Hluštík, P.

2017-10-01

This article deals with a comparison of vacuum sewerage system and gravity based sewerage system. It also includes the results of the comparison of both of these systems from various cities, and there are measures suggested on the basis of the findings focused on increasing the efficiency and reducing the operational costs of the selected vacuum sewerage system.

Design of vacuum vessel for Indian Test Facility (INTF) for 100 keV neutral beams

International Nuclear Information System (INIS)

Joshi, Jaydeep; Yadav, Ashish; Gangadharan, Roopesh; Prasad, Rambilas; Ulahannan, Shino; Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun

2015-01-01

Highlights: • Thickness calculation and optimization for the main shell, ducts, Dishends and top lid on the main shell. • Nozzle and flange design for the port openings. • Support structure design for the main shell and ducts. • FEA validation of the INTF vessel for operational, seismic and lifting condition. - Abstract: The Indian Test Facility (INTF) vacuum vessel is designed to install a full-scale test set-up of Diagnostic Neutral Beam (DNB) [1] for the qualification of beam parameters and the behavior of beam-line components prior to installation and operation in ITER. Vacuum vessel is designed in cylindrical shape having length of ∼9 m with diameter of ∼4.5 m and has a detachable top-lid for mounting as well as removal of internal components during installation and maintenance phases. The Vessel has hemispherical dish-ends with large openings for high-voltage bushing on one side and duct on another side. Vessel is provided with openings for hydraulic, cryo, gas-feed and diagnostics. Vessel duct is composed of three segments with length ranges from 3 m to 5 m with diameter of ∼1.5 m and one vessel at the end to house the second calorimeter. The objective of this paper is to present the design and analysis of vacuum vessel, with respect to its functional and operational requirements. The design calculations are done as per ASME-BPVC SectionVIII-Div.1 and subsequently Finite Element Analysis (FEM) method has been adopted to verify the design.

Design of vacuum vessel for Indian Test Facility (INTF) for 100 keV neutral beams

Energy Technology Data Exchange (ETDEWEB)

Joshi, Jaydeep, E-mail: Jaydeep.joshi@iter-india.org [ITER-India, Institute for Plasma Research, A29, GIDC Electronics Estate, Gandhinagar 382016, Gujarat (India); Yadav, Ashish; Gangadharan, Roopesh [ITER-India, Institute for Plasma Research, A29, GIDC Electronics Estate, Gandhinagar 382016, Gujarat (India); Prasad, Rambilas [Madan Mohan Malaviya University of Technology, Gorakhpur, Uttar Pradesh 273001 (India); Ulahannan, Shino [Airframe Aerodesigns Pvt. Ltd., HAL Airport Exit Road, Old Airport Road, Bengaluru 17 (India); Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun [ITER-India, Institute for Plasma Research, A29, GIDC Electronics Estate, Gandhinagar 382016, Gujarat (India)

2015-10-15

Highlights: • Thickness calculation and optimization for the main shell, ducts, Dishends and top lid on the main shell. • Nozzle and flange design for the port openings. • Support structure design for the main shell and ducts. • FEA validation of the INTF vessel for operational, seismic and lifting condition. - Abstract: The Indian Test Facility (INTF) vacuum vessel is designed to install a full-scale test set-up of Diagnostic Neutral Beam (DNB) [1] for the qualification of beam parameters and the behavior of beam-line components prior to installation and operation in ITER. Vacuum vessel is designed in cylindrical shape having length of ∼9 m with diameter of ∼4.5 m and has a detachable top-lid for mounting as well as removal of internal components during installation and maintenance phases. The Vessel has hemispherical dish-ends with large openings for high-voltage bushing on one side and duct on another side. Vessel is provided with openings for hydraulic, cryo, gas-feed and diagnostics. Vessel duct is composed of three segments with length ranges from 3 m to 5 m with diameter of ∼1.5 m and one vessel at the end to house the second calorimeter. The objective of this paper is to present the design and analysis of vacuum vessel, with respect to its functional and operational requirements. The design calculations are done as per ASME-BPVC SectionVIII-Div.1 and subsequently Finite Element Analysis (FEM) method has been adopted to verify the design.

Chiral vacuum alignment and spontaneous CP violation by four-Fermi operators

International Nuclear Information System (INIS)

Rador, Tonguc

2009-01-01

In models where there is a global chiral symmetry which spontaneously breaks to its vectorial subgroup, the introduction of an explicit symmetry breaking perturbation will define the true vacuum of the theory. This true vacuum is found via the minimization of the expectation value of the perturbing Hamiltonian between different vacua as prescribed by Dashen. The procedure of finding the correct vacuum of the theory may result in the spontaneous breaking of CP symmetry even if one initially demands CP invariance on the perturbation. In this work we study, in detail, models where the perturbation is provided by four-Fermi operators. We present the exact treatment for models with two fermion flavors and study the three flavor case in depth numerically. We show that after the Dashen procedure is applied the solutions for the true vacuum fall in three classes with different CP breaking patterns. Critical transitions are possible between these classes as one varies the parameters of the perturbation. We rigorously show that at these transitions a pseudo-Goldstone boson mass vanishes. We also advocate, and substantiate with numerical statistical analysis for various types of models, that if one imposes CP invariance on the perturbation before solving the vacuum alignment, the resulting vacuum structure will have a sizable probability for a light pseudo-Goldstone boson mass. That is a statistical variant of Peccei-Quinn mechanism can be speculated to operate.

Optimal Operation of a Josephson Parametric Amplifier for Vacuum Squeezing

Science.gov (United States)

Malnou, M.; Palken, D. A.; Vale, Leila R.; Hilton, Gene C.; Lehnert, K. W.

2018-04-01

A Josephson parametric amplifier (JPA) can create squeezed states of microwave light, lowering the noise associated with certain quantum measurements. We experimentally study how the JPA's pump influences the phase-sensitive amplification and deamplification of a coherent tone's amplitude when that amplitude is commensurate with vacuum fluctuations. We predict and demonstrate that, by operating the JPA with a single current pump whose power is greater than the value that maximizes gain, the amplifier distortion is reduced and, consequently, squeezing is improved. Optimizing the singly pumped JPA's operation in this fashion, we directly observe 3.87 ±0.03 dB of vacuum squeezing over a bandwidth of 30 MHz.

Operating status of TARN vacuum system and future tasks

International Nuclear Information System (INIS)

Chida, Katsuhisa; Tsujikawa, Hiroshi; Mizobuchi, Akira

1981-01-01

TARN (Test Accumulation Ring for Numatron) was constructed for the purpose of obtaining the fundamental data for high energy heavy ion accelerator (Numatron) project, which accelerates heavy ions up to uranium to 1 GeV/nucleon. Its vacuum is required to be 1 x 10 - 10 Torr or less on beam. In February, 1972, only the vacuum system was temporarily assembled, and the vacuum of 2 x 10 - 11 Torr was realized by baking at 300 deg C alone. In July, 1972, the assembling of the vacuum chamber into magnets was completed, and several test experiments were performed using the H 2+ beam from the SF cyclotron. In this report, first, the outline of the vacuum system, and next, its operation are described. For the reason of the purpose of the ring, the vacuum system is required to be atmospheric pressure to attach beam monitors and other measuring instruments just before the machine time. Therefore, it is an important task to make the evacuation time as short as possible. As future tasks, the examination on the material and shape of the chamber, the investigation of pump system (appropriate combination of ion pump, titanium sublimation pump, cryo-pump, molecular pump, etc.), the study on the measuring and control systems (accurate measurement of total pressure and partial pressure and the feedback to the protecting system), the studies of problems on the vacuum wall surface (surface treatment prior to assembling the chamber into the ring and the methods and the effects of baking and electric discharge cleaning) are included. (Wakatsuki, Y.)

The thin-wall tube drift chamber operating in vacuum (prototype)

Science.gov (United States)

Alexeev, G. D.; Glonti, L. N.; Kekelidze, V. D.; Malyshev, V. L.; Piskun, A. A.; Potrbenikov, Yu. K.; Rodionov, V. K.; Samsonov, V. A.; Tokmenin, V. V.; Shkarovskiy, S. N.

2013-08-01

The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. "Self-centering" spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

The thin-wall tube drift chamber operating in vacuum (prototype)

International Nuclear Information System (INIS)

Alexeev, G.D.; Glonti, L.N.; Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N.

2013-01-01

The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum

The thin-wall tube drift chamber operating in vacuum (prototype)

Energy Technology Data Exchange (ETDEWEB)

Alexeev, G.D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Glonti, L.N., E-mail: glonti@sunse.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

2013-08-01

The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

Vacuum boundary modifications of the RFX-mod machine

Energy Technology Data Exchange (ETDEWEB)

Patel, Nisarg, E-mail: nisarg.patel@igi.cnr.it [University of Padova,Via 8 Febbraio 2, Padova 35122 (Italy); Consorzio RFX, Corso StatiUniti 4, Padova 35127 (Italy); Dalla Palma, Mauro; Dal Bello, Samuele; Grando, Luca; Peruzzo, Simone [Consorzio RFX, Corso StatiUniti 4, Padova 35127 (Italy); Sonato, Piergiorgio [University of Padova,Via 8 Febbraio 2, Padova 35122 (Italy); Consorzio RFX, Corso StatiUniti 4, Padova 35127 (Italy)

2016-11-01

Highlights: • Different vacuum sealing solutions are designed for cuts of Toroidal Support Structure. • New supporting rings are designed for In-TSS components. • Identified integration of the sub-assemblies. • Thermo-mechanical behaviour of components are verified against standard design rules. - Abstract: The results produced by experimental campaigns of RFX-mod shows the need to improve passive MHD control and minimise braking torque on plasma. These improvements require major mechanical changes on the present components of the machine including first wall, vacuum vessel, and toroidal support structure (TSS). The vacuum vessel will be removed and the first wall tiles will be directly supported by the passive stabilising shell, so increasing the poloidal cross section by 28 mm radially and bringing the passive stabilising shell as close as possible to the plasma boundary. This paper presents the mechanical design modifications of the torus assembly. Composite rings are designed to support the passive stabilising shell on the TSS. The vacuum boundary is shifted at the TSS by developing different joint solutions compatible with the stringent requirements of the present components: ceramic-metal brazed rings at the two poloidal joints, fully welded solution at the external equatorial joint, and resistive weld plate at the internal equatorial joint. The vacuum vessel portholes for pumping, fuelling, diagnostics, and sensor cable routing are redesigned to be integrated onto the TSS. The design is supported by thermo-mechanical analyses and verifications carried out applying load combinations corresponding to the expected load cases.

On-shell gauge-parameter independence of contributions to electroweak quark self-energies

International Nuclear Information System (INIS)

Ahmady, M.R.; Elias, V.; Mendel, R.R.; Scadron, M.D.; Steele, T.

1989-01-01

We allow an external condensate to enter standard SU(2) x U(1) electroweak theory via the vacuum expectation value , as in QCD sum-rule applications. For a given flavor, we then find that any gauge-parameter dependence of quark self-energies on the ''mass shell'' is eliminated provided that the mass shell is made to coincide with both the expansion-parameter mass occurring in the operator-product expansion of and the standard electroweak mass acquired via the Yukawa coupling to the usual scalar vacuum expectation value of spontaneous symmetry breaking. This result indicates that if the QCD-generated order parameter and associated dynamical mass(es) m/sub q//sup dyn/ are utilized as external input parameters in electroweak calculations involving hadrons, then new corrections must be introduced into the q-barqW and q-barqZ vertices in order to preserve SU(2) x U(1) Ward identities

Fermionic vacuum polarization by a cylindrical boundary in the cosmic string spacetime

International Nuclear Information System (INIS)

Bezerra de Mello, E. R.; Bezerra, V. B.; Saharian, A. A.; Tarloyan, A. S.

2008-01-01

The vacuum expectation values of the energy-momentum tensor and the fermionic condensate are analyzed for a massive spinor field obeying the MIT bag boundary condition on a cylindrical shell in the cosmic string spacetime. Both regions inside and outside the shell are considered. By applying to the corresponding mode sums a variant of the generalized Abel-Plana formula, we explicitly extract the parts in the expectation values corresponding to the cosmic string geometry without boundaries. In this way the renormalization procedure is reduced to that for the boundary-free cosmic string spacetime. The parts induced by the cylindrical shell are presented in terms of integrals rapidly convergent for points away from the boundary. The behavior of the vacuum densities is investigated in various asymptotic regions of the parameters. In the limit of large values of the planar angle deficit, the boundary-induced expectation values are exponentially suppressed. As a special case, we discuss the fermionic vacuum densities for the cylindrical shell on the background of the Minkowski spacetime.

Modal analysis of a stiffened toroidal shell sector

International Nuclear Information System (INIS)

Cerreta, R.; Di Pietro, E.; Pizzuto, A.

1987-01-01

This paper presents the results of the modal analysis of a sector of the toroidal vacuum vessel of a new experimental machine for research in the field of controlled thermonuclear fusion (FTU - Frascati Tokamak Upgrade). The vacuum vessel, one of the most critical components of the experimental device, consist of 12 stainless steel toroidal sectors, and it is designed to withstand pulsed electromagnetic loads during operation. Results of the modal analysis of the stiffened toroidal shell sector are compared and discussed with regard to the experimental data. Theoretical eigenvalues and eigenvectors have been predicted by means of ABAQUS finite element code. Experimental analysis has been carried out on a full scale model and natural frequencies have been measured. Satisfactory agreement between experimental and theoretical eigenvalues has been found

Design of the ITER vacuum vessel

International Nuclear Information System (INIS)

Ioki, K.; Johnson, G.; Shimizu, K.; Williamson, D.

1995-01-01

The ITER vacuum vessel is a major safety barrier and must support electromagnetic loads during plasma disruptions and vertical displacement events (VDE) and withstand plausible accidents without losing confinement.The vacuum vessel has a double wall structure to provide structural and electrical continuity in the toroidal direction. The inner and outer shells and poloidal stiffening ribs between them are joined by welding, which gives the vessel the required mechanical strength. The space between the shells will be filled with steel balls and plate inserts to provide additional nuclear shielding. Water flowing in this space is required to remove nuclear heat deposition, which is 0.2-2.5% of the total fusion power. The minor and major radii of the tokamak are 3.9 m and 13 m respectively, and the overall height is 15 m. The total thickness of the vessel wall structure is 0.4-0.7 m.The inboard and outboard blanket segments are supported from the vacuum vessel. The support structure is required to withstand a large total vertical force of 200-300 MN due to VDE and to allow for differential thermal expansion.The first candidate for the vacuum vessel material is Inconel 625, due to its higher electric resistivity and higher yield strength, even at high temperatures. Type 316 stainless steel is also considered a vacuum vessel material candidate, owing to its large database and because it is supported by more conventional fabrication technology. (orig.)

Analysis of the steady-state operation of vacuum systems for fusion machines

International Nuclear Information System (INIS)

Roose, T.R.; Hoffman, M.A.; Carlson, G.A.

1975-01-01

A computer code named GASBAL was written to calculate the steady-state vacuum system performance of multi-chamber mirror machines as well as rather complex conventional multichamber vacuum systems. Application of the code, with some modifications, to the quasi-steady tokamak operating period should also be possible. Basically, GASBAL analyzes free molecular gas flow in a system consisting of a central chamber (the plasma chamber) connected by conductances to an arbitrary number of one- or two-chamber peripheral tanks. Each of the peripheral tanks may have vacuum pumping capability (pumping speed), sources of cold gas, and sources of energetic atoms. The central chamber may have actual vacuum pumping capability, as well as a plasma capable of ionizing injected atoms and impinging gas molecules and ''pumping'' them to a peripheral chamber. The GASBAL code was used in the preliminary design of a large mirror machine experiment--LLL's MX

Electric circuit breaker comprising a plurality of vacuum interrupters simultaneously operated by a common operator

Science.gov (United States)

Barkan, Philip; Imam, Imdad

1980-01-01

This circuit breaker comprises a plurality of a vacuum-type circuit interrupters, each having a movable contact rod. A common operating device for the interrupters comprises a linearly-movable operating member. The interrupters are mounted at one side of the operating member with their movable contact rods extending in a direction generally toward the operating member. Means is provided for mechanically coupling the operating member to the contact rods, and this means comprises a plurality of insulating operating rods, each connected at one end to the operating member and at its opposite end to one of the movable contact rods. The operating rods are of substantially equal length and have longitudinal axes that converge and intersect at substantially a common point.

Operator product expansions on the vacuum in conformal quantum field theory in two spacetime dimensions

International Nuclear Information System (INIS)

Luescher, M.

1975-11-01

Let phi 1 (x) and phi 2 (y) be two local fields in a conformal quantum field theory (CQFT) in two-dimensional spacetime. It is then shown that the vector-valued distribution phi 1 (x) phi 2 (y) /0 > is a boundary value of a vector-valued holomorphic function which is defined on a large conformally invariant domain. By group theoretical arguments alone it is proved that phi 1 (x) phi 2 (y) /0 > can be expanded into conformal partial waves. These have all the properties of a global version of Wilson's operator product expansions when applied to the vacuum state /0 >. Finally, the corresponding calculations are carried out more explicitly in the Thirring model. Here, a complete set of local conformally covariant fields is found, which is closed under vacuum expansion of any two of its elements (a vacuum expansion is an operator product expansion applied to the vacuum). (orig.) [de

Darlington GS vacuum building - containment shell

International Nuclear Information System (INIS)

Huterer, J.; Ha, E.C.; Brown, D.G.; Cheng, P.C.

1985-01-01

The paper describes the consequences of new design requirements for the Darlington vacuum building on its structural configuration, analytical and reinforcing steel layout. Attention focuses on the ring girder where the juncture of dome and perimeter wall produces a complex post-tensioning layout, and attendant difficulties in design and construction. At the wall base, full fixity imposes large local stresses. Long-term, shrinkage and creep, and temperature effects become significant. A research program and in-house analytical procedure established time-dependent concrete behaviour and corresponding wall-sectional stresses. The outcome is examined in terms of reinforcement, temperature controls, and wall liner requirements. (orig.)

Corrections to the neutrinoless double-β-decay operator in the shell model

Science.gov (United States)

Engel, Jonathan; Hagen, Gaute

2009-06-01

We use diagrammatic perturbation theory to construct an effective shell-model operator for the neutrinoless double-β decay of Se82. The starting point is the same Bonn-C nucleon-nucleon interaction that is used to generate the Hamiltonian for recent shell-model calculations of double-β decay. After first summing high-energy ladder diagrams that account for short-range correlations and then adding diagrams of low order in the G matrix to account for longer-range correlations, we fold the two-body matrix elements of the resulting effective operator with transition densities from the recent shell-model calculation to obtain the overall nuclear matrix element that governs the decay. Although the high-energy ladder diagrams suppress this matrix element at very short distances as expected, they enhance it at distances between one and two fermis, so that their overall effect is small. The corrections due to longer-range physics are large, but cancel one another so that the fully corrected matrix element is comparable to that produced by the bare operator. This cancellation between large and physically distinct low-order terms indicates the importance of a reliable nonperturbative calculation.

The hadronic vacuum polarization and automatic O(a) improvement for twisted mass fermions

International Nuclear Information System (INIS)

Burger, Florian; Hotzel, Grit

2014-12-01

The vacuum polarization tensor and the corresponding vacuum polarization function are the basis for calculations of numerous observables in lattice QCD. Examples are the hadronic contributions to lepton anomalous magnetic moments, the running of the electroweak and strong couplings and quark masses. Quantities which are derived from the vacuum polarization tensor often involve a summation of current correlators over all distances in position space leading thus to the appearance of short-distance terms. The mechanism of O(a) improvement in the presence of such short-distance terms is not directly covered by the usual arguments of on-shell improvement of the action and the operators for a given quantity. If such short-distance contributions appear, the property of O(a) improvement needs to be reconsidered. We discuss the effects of these short-distance terms on the vacuum polarization function for twisted mass lattice QCD and find that even in the presence of such terms automatic O(a) improvement is retained if the theory is tuned to maximal twist.

Operational characteristics of VEC vacuum system

International Nuclear Information System (INIS)

Viswanadham, C.; Bhavsar, S.T.; Bose, D.K.; Chintalapudi, S.N.; Das, S.K.; Tiwary, S.D.

1979-01-01

The main vacuum system of the Variable Energy Cyclotron which has been built indigenously has fulfilled the requirements for the smooth operation of the machine. By running two 88.9 cm diffusion pumps with freon cooled baffles and backed by 600 l/m rotary pumps, a pressure of 5 x 10 -6 torr in absence of the beam and 1 x 10 -5 torr in presence of the beam is readily achieved in the 23 m 3 volume. Various means have been adopted to maintain the system in order and contamination-free, by maintaining a pressure level of 1 x 10 -4 torr throughout the working week by a 30 cm diffusion pump, which can run even on emergency power. Cryopanels have also been installed and tried out. Details of pump-down characteristics and system performance are discussed. (auth.)

Vacuum expectation values of high-dimensional operators and their contributions to the Bjorken and Ellis-Jaffe sum rules

International Nuclear Information System (INIS)

Oganesian, A.G.

1998-01-01

A method is proposed for estimating unknown vacuum expectation values of high-dimensional operators. The method is based on the idea that the factorization hypothesis is self-consistent. Results are obtained for all vacuum expectation values of dimension-7 operators, and some estimates for dimension-10 operators are presented as well. The resulting values are used to compute corrections of higher dimensions to the Bjorken and Ellis-Jaffe sum rules

HANFORD DOUBLE SHELL TANK (DST) THERMAL & SEISMIC PROJECT SUMMARY OF COMBINED THERMAL & OPERATING LOADS

Energy Technology Data Exchange (ETDEWEB)

MACKEY, T.C.

2006-03-17

This report summarizes the results of the Double-Shell Tank Thermal and Operating Loads Analysis (TOLA) combined with the Seismic Analysis. This combined analysis provides a thorough, defensible, and documented analysis that will become a part of the overall analysis of record for the Hanford double-shell tanks (DSTs).

Spinor Casimir densities for a spherical shell in the global monopole spacetime

International Nuclear Information System (INIS)

Saharian, A A; Mello, E R Bezerra de

2004-01-01

We investigate the vacuum expectation values of the energy-momentum tensor and the fermionic condensate associated with a massive spinor field obeying the MIT bag boundary condition on a spherical shell in the global monopole spacetime. In order to do that, we use the generalized Abel-Plana summation formula. As we shall see, this procedure allows us to extract from the vacuum expectation values the contribution coming from the unbounded spacetime and to explicitly present the boundary induced parts. As regards the boundary induced contribution, two distinct situations are examined: the vacuum average effects inside and outside the spherical shell. The asymptotic behaviour of the vacuum densities is investigated near the sphere centre and near the surface, and at large distances from the sphere. In the limit of strong gravitational field corresponding to small values of the parameter describing the solid angle deficit in the global monopole geometry, the sphere induced expectation values are exponentially suppressed. We discuss, as a special case, the fermionic vacuum densities for the spherical shell on the background of the Minkowski spacetime. Previous approaches to this problem within the framework of the QCD bag models have been global and our calculation is a local extension of these contributions

Preparation of hydrosol suspensions of elemental and core–shell nanoparticles by co-deposition with water vapour from the gas-phase in ultra-high vacuum conditions

International Nuclear Information System (INIS)

Binns, Chris; Prieto, Pilar; Baker, Stephen; Howes, Paul; Dondi, Ruggero; Burley, Glenn; Lari, Leonardo; Kröger, Roland; Pratt, Andrew; Aktas, Sitki; Mellon, John K.

2012-01-01

We report a new method to produce liquid suspensions of nanoparticles by co-deposition with water vapour from the gas-phase in ultra-high vacuum (UHV) conditions. The water is injected from outside the vacuum as a molecular beam onto a substrate maintained at 77 K and forms an ice layer with a UHV vapour pressure. Molecular dynamics simulations confirm that the nanoparticles are soft-landed close to the surface of the growing ice layer. We show that the un-agglomerated size distribution within the liquid is similar to the gas-phase size distribution and demonstrate that the inclusion of surfactants in the injected water prevents agglomeration. The method allows the flexibility and tight size control available with gas-phase production methods to be applied to making nanoparticle suspensions with any desired properties. This is important for practical applications, especially in medicine. We have extended the method to include core–shell nanoparticles, in which there is flexible control over the core size and shell thickness and free choice of the material in either. Here, we report the production of suspensions of Cu, Ag and Au elemental nanoparticles and Fe-Au and Fe-Fe-oxide core–shell nanoparticles with diameters in the range 5–15 nm. We demonstrate the power of the method in practical applications in the case of Fe-Fe-oxide nanoparticles, which have a specific absorption rate of an applied oscillating magnetic field that is significantly higher than available Fe-oxide nanoparticle suspensions and the highest yet reported. These will thus have a very high-performance in the treatment of tumours by magnetic nanoparticle hyperthermia.

Thermal structural analysis of SST-1 vacuum vessel and cryostat assembly using ANSYS

International Nuclear Information System (INIS)

Santra, Prosenjit; Bedakihale, Vijay; Ranganath, Tata

2009-01-01

Steady state super-conducting tokamak-1 (SST-1) is a medium sized tokamak, which has been designed to produce a 'D' shaped double null divertor plasma and operate in quasi steady state (1000 s). SST-1 vacuum system comprises of plasma chamber (vacuum vessel, interconnecting rings, baking and cooling channels), and cryostat all made of SS 304L material designed to meet ultra high vacuum requirements for plasma generation and confinement. Prior to plasma shot and operation the vessel assembly is baked to 250/150 deg. C from room temperature and discharge cleaned to remove impurities/trapped gases from wall surfaces. Due to baking the non-uniform temperature pattern on the vessel assembly coupled with atmospheric pressure loading and self-weight give rise to high thermal-structural stresses, which needs to be analyzed in detail. In addition the vessel assembly being a thin shell vessel structure needs to be checked for critical buckling load caused by atmospheric and baking thermal loads. Considering symmetry of SST-1, 1/16th of the geometry is modeled for finite element (FE) analysis using ANSYS for different loading scenarios, e.g. self-weight, pressure loading considering normal operating conditions, and off-normal loads coupled with baking of vacuum vessel from room temperature 250 deg. C to 150 deg. C, buckling and modal analysis for future dynamic analysis. The paper will discuss details about SST-1 vacuum system/cryostat, solid and FE model of SST-1, different loading scenarios, material details and the stress codes used. We will also present the thermal structural results of FE analysis using ANSYS for various load cases being investigated and our observations under different loading conditions.

MEA vacuum system

International Nuclear Information System (INIS)

Stroo, R.; Schwebke, H.; Heine, E.

1984-01-01

This report describes construction and operation of the MEA vacuum system of NIKHEF (Netherlands). First, the klystron vacuum system, beam transport system, diode pump and a triode pump are described. Next, the isolation valve and the fast valves of the vacuum system are considered. Measuring instruments, vacuum system commands and messages of failures are treated in the last chapter. (G.J.P.)

Advanced light source vacuum policy and vacuum guidelines for beamlines and experiment endstations

International Nuclear Information System (INIS)

Hussain, Z.

1995-08-01

The purpose of this document is to: (1) Explain the ALS vacuum policy and specifications for beamlines and experiment endstations. (2) Provide guidelines related to ALS vacuum policy to assist in designing beamlines which are in accordance with ALS vacuum policy. This document supersedes LSBL-116. The Advanced Light Source is a third generation synchrotron radiation source whose beam lifetime depends on the quality of the vacuum in the storage ring and the connecting beamlines. The storage ring and most of the beamlines share a common vacuum and are operated under ultra-high-vacuum (UHV) conditions. All endstations and beamline equipment must be operated so as to avoid contamination of beamline components, and must include proper safeguards to protect the storage ring vacuum from an accidental break in the beamline or endstation vacuum systems. The primary gas load during operation is due to thermal desorption and electron/photon induced desorption of contaminants from the interior of the vacuum vessel and its components. The desorption rates are considerably higher for hydrocarbon contamination, thus considerable emphasis is placed on eliminating these sources of contaminants. All vacuum components in a beamline and endstation must meet the ALS vacuum specifications. The vacuum design of both beamlines and endstations must be approved by the ALS Beamline Review Committee (BRC) before vacuum connections to the storage ring are made. The vacuum design is first checked during the Beamline Design Review (BDR) held before construction of the beamline equipment begins. Any deviation from the ALS vacuum specifications must be approved by the BRC prior to installation of the equipment on the ALS floor. Any modification that is incorporated into a vacuum assembly without the written approval of the BRC is done at the user's risk and may lead to rejection of the whole assembly

Demonstration tests for manufacturing the ITER vacuum vessel

International Nuclear Information System (INIS)

Shimizu, Katsusuke; Onozuka, Masanori; Usui, Yukinori; Urata, Kazuhiro; Tsujita, Yoshihiro; Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Ohmori, Junji; Shibanuma, Kiyoshi

2007-01-01

Demonstration tests for manufacturing and assembly of the International Thermonuclear Experimental Reactor (ITER) vacuum vessel have been conducted to confirm manufacturing and assembly process of the vacuum vessel (VV). The full-scale partial mock-up fabrication was planned and is in progress. The results will be available in the near future. Field-joint assembly procedure has been demonstrated using a test stand. Due to limited accessibility to the outer shell at the field joint, some operations, including alignment of the splice plates, field-joint welding, and examination, were found to be very difficult. In addition, a demonstration test on the selected back-seal structures was performed. It was found that the tested structures have insufficient sealing capabilities and need further improvement. The applicability of ultrasonic testing methods has been investigated. Although side drilled holes of 2.4 mm in diameter were detected, detection of the slit-type defects and defect characterization were found to be difficult. Feasibility test of liquid penetrant testing has revealed that the selected liquid penetrant testing (LPT) solutions have sufficient low outgas rates and are applicable to the VV

Demonstration tests for manufacturing the ITER vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Katsusuke [Mitsubishi Heavy Industries, Ltd., Kobe Shipyard and Machinery Works, Wadasaki-cho 1-1-1, Hyogo-ku, Kobe 652-8585 (Japan)], E-mail: katsusuke_shimizu@mhi.co.jp; Onozuka, Masanori [Mitsubishi Heavy Industries, Ltd., Konan 2-16-5, Minato-ku, Tokyo 108-8215 (Japan); Usui, Yukinori; Urata, Kazuhiro; Tsujita, Yoshihiro [Mitsubishi Heavy Industries, Ltd., Kobe Shipyard and Machinery Works, Wadasaki-cho 1-1-1, Hyogo-ku, Kobe 652-8585 (Japan); Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Ohmori, Junji; Shibanuma, Kiyoshi [Japan Atomic Energy Agency, Mukouyama 801-1, Naka-machi, Naka-gun, Ibaraki 311-0193 (Japan)

2007-10-15

Demonstration tests for manufacturing and assembly of the International Thermonuclear Experimental Reactor (ITER) vacuum vessel have been conducted to confirm manufacturing and assembly process of the vacuum vessel (VV). The full-scale partial mock-up fabrication was planned and is in progress. The results will be available in the near future. Field-joint assembly procedure has been demonstrated using a test stand. Due to limited accessibility to the outer shell at the field joint, some operations, including alignment of the splice plates, field-joint welding, and examination, were found to be very difficult. In addition, a demonstration test on the selected back-seal structures was performed. It was found that the tested structures have insufficient sealing capabilities and need further improvement. The applicability of ultrasonic testing methods has been investigated. Although side drilled holes of 2.4 mm in diameter were detected, detection of the slit-type defects and defect characterization were found to be difficult. Feasibility test of liquid penetrant testing has revealed that the selected liquid penetrant testing (LPT) solutions have sufficient low outgas rates and are applicable to the VV.

Production of bio-fertilizer from microwave vacuum pyrolysis of waste palm shell for cultivation of oyster mushroom (Pleurotus ostreatus

Directory of Open Access Journals (Sweden)

Nam Wai Lun

2017-01-01

Full Text Available Microwave vacuum pyrolysis of waste palm shell (WPS was performed to produce biochar, which was then tested as bio-fertilizer in growing Oyster mushroom (Pleurotus ostreatus. The pyrolysis approach generated a biochar containing a highly porous structure with a high BET surface area (up to 1250 m2/g and a low moisture content (≤ 10 wt%, exhibiting desirable adsorption properties to be used as bio-fertilizer since it can act as a housing that provides many sites on which living microorganisms (mycelium or plant-growth promoting bacteria and organic nutrients can be attached or adsorbed onto. This could in turn stimulate plant growth by increasing the availability and supply of nutrients to the targeted host plant. The results from growing Oyster mushroom using the biochar record an impressive growth rate and a monthly production of up to about 550 g of mushroom. The shorter time for mycelium growth on whole baglog (30 days and the highest yield of Oyster mushroom (550 g was obtained from the cultivation medium added with 20 g of biochar. Our results demonstrate that the biochar-based bio-fertilizer produce from microwave vacuum pyrolysis of WPS show exceptional promise as an alternative growing substrate for mushroom cultivation.

Production of bio-fertilizer from microwave vacuum pyrolysis of waste palm shell for cultivation of oyster mushroom (Pleurotus ostreatus)

Science.gov (United States)

Lun Nam, Wai; Huan Su, Man; Phang, Xue Yee; Chong, Min Yee; Keey Liew, Rock; Ma, Nyuk Ling; Lam, Su Shiung

2017-11-01

Microwave vacuum pyrolysis of waste palm shell (WPS) was performed to produce biochar, which was then tested as bio-fertilizer in growing Oyster mushroom (Pleurotus ostreatus). The pyrolysis approach generated a biochar containing a highly porous structure with a high BET surface area (up to 1250 m2/g) and a low moisture content (≤ 10 wt%), exhibiting desirable adsorption properties to be used as bio-fertilizer since it can act as a housing that provides many sites on which living microorganisms (mycelium or plant-growth promoting bacteria) and organic nutrients can be attached or adsorbed onto. This could in turn stimulate plant growth by increasing the availability and supply of nutrients to the targeted host plant. The results from growing Oyster mushroom using the biochar record an impressive growth rate and a monthly production of up to about 550 g of mushroom. The shorter time for mycelium growth on whole baglog (30 days) and the highest yield of Oyster mushroom (550 g) was obtained from the cultivation medium added with 20 g of biochar. Our results demonstrate that the biochar-based bio-fertilizer produce from microwave vacuum pyrolysis of WPS show exceptional promise as an alternative growing substrate for mushroom cultivation.

Vacuum Exhaust Process in Pilot-Scale Vacuum Pressure Swing Adsorption for Coal Mine Ventilation Air Methane Enrichment

Directory of Open Access Journals (Sweden)

Xiong Yang

2018-04-01

Full Text Available Recovery and treatment of methane from coal mine ventilation air methane (VAM with cost-effective technologies have been an ongoing challenge due to low methane concentrations. In this study, a type of coconut shell-based active carbon was employed to enrich VAM with a three-bed vacuum pressure swing adsorption unit. A new vacuum exhaust step for the VPSA process was introduced. The results show that the vacuum exhaust step can increase the methane concentration of the product without changing adsorption and desorption pressure. Under laboratory conditions, the concentration of product increased from 0.4% to 0.69% as the vacuum exhaust ratio increased from 0 to 3.1 when the feed gas concentration was 0.2%. A 500 m³/h pilot-scale test system for VAM enrichment was built rendering good correlation with the laboratory results in terms of the vacuum exhaust step. By using a two-stage three-bed separation unit, the VAM was enriched from 0.2% to over 1.2%.

Bingham Sealing and Application in Vacuum Clamping

Science.gov (United States)

Yao, S. M.; Teo, Wee Kin; Geng, Zunmin; Turner, Sam; Ridgway, Keith

2011-12-01

Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of "O"ring sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with "O" ring sealing.

Bingham Sealing and Application in Vacuum Clamping

International Nuclear Information System (INIS)

Yao, S M; Teo, Wee Kin; Geng Zunmin; Turner, Sam; Ridgway, Keith

2011-01-01

Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of Or ing sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with 'O' ring sealing.

Vacuum system for ISABELLE

International Nuclear Information System (INIS)

Hobson, J.P.

1975-01-01

An analysis is presented of the proposed vacuum system for the planned ISABELLE storage rings with respect to acceptability and practicality from the vacuum viewport. A comparison is made between the proposed vacuum system and the vacuum system at the CERN ISR, and some comments on various design and operational parameters are made

Butterfly tachyons in vacuum string field theory

International Nuclear Information System (INIS)

Matlock, Peter

2003-01-01

We use geometrical conformal field theory methods to investigate tachyon fluctuations about the butterfly projector state in vacuum string field theory. We find that the on-shell condition for the tachyon field is equivalent to the requirement that the quadratic term in the string-field action vanish on shell. This further motivates the interpretation of the butterfly state as a D-brane. We begin a calculation of the tension of the butterfly, and conjecture that this will match the case of the sliver and further strengthen this interpretation

Enhancing Ethanol Production by Fermentation Using Saccharomyces cereviseae under Vacuum Condition in Batch Operation

Directory of Open Access Journals (Sweden)

A Abdullah

2012-02-01

Full Text Available Ethanol is one of renewable energy, which considered being an excellent alternative clean-burning fuel to replaced gasoline. In fact, the application of ethanol as fuel still blended with gasoline. The advantages of using ethanol as fuel are that the raw material mostly from renewable resources and the product has low emission which means environmental friendly. Ethanol can be produced by fermentation of sugars (glucose/fructose. The constraint in the ethanol fermentation batch or continuous process is the ethanol product inhibition. Inhibition in ethanol productivity and cell growth can be overcome by taking the product continuously from the fermentor. The process can be done by using a vacuum fermentation. The objective of this research is to investigate the effect of pressure and glucose concentration in ethanol fermentation. The research was conducted in laboratory scale and batch process. Equipment consists of fermentor with vacuum system. The observed responses were dried cells of yeast, concentration of glucose, and concentration of ethanol. Observations were made every 4 hours during a day of experiment. The results show that the formation of ethanol has a growth-associated product characteristic under vacuum operation. Vacuum condition can increase the cell formation productivity and the ethanol formation, as it is compared with fermentation under atmospheric condition. The maximum cells productivity and ethanol formation in batch operation under vacuum condition was reached at 166.6 mmHg of pressure. The maximum numbers of cells and ethanol formation was reached at 141.2 mm Hg of pressure. High initial glucose concentration significantly can affect the productivity and the yield of ethanol.

Entanglement between smeared field operators in the Klein-Gordon vacuum

International Nuclear Information System (INIS)

Zych, Magdalena; Costa, Fabio; Kofler, Johannes; Brukner, Caslav

2010-01-01

Quantum field theory is the application of quantum physics to fields. It provides a theoretical framework widely used in particle physics and condensed matter physics. One of the most distinct features of quantum physics with respect to classical physics is entanglement or the existence of strong correlations between subsystems that can even be spacelike separated. In quantum fields, observables restricted to a region of space define a subsystem. While there are proofs on the existence of local observables that would allow a violation of Bell's inequalities in the vacuum states of quantum fields as well as some explicit but technically demanding schemes requiring an extreme fine-tuning of the interaction between the fields and detectors, an experimentally accessible entanglement witness for quantum fields is still missing. Here we introduce smeared field operators which allow reducing the vacuum to a system of two effective bosonic modes. The introduction of such collective observables is motivated by the fact that no physical probe has access to fields in single spatial (mathematical) points but rather smeared over finite volumes. We first give explicit collective observables whose correlations reveal vacuum entanglement in the Klein-Gordon field. We then show that the critical distance between the two regions of space above which two effective bosonic modes become separable is of the order of the Compton wavelength of the particle corresponding to the massive Klein-Gordon field.

Thin-shell bubbles and information loss problem in anti de Sitter background

Energy Technology Data Exchange (ETDEWEB)

Sasaki, Misao [Yukawa Institute for Theoretical Physics,Kyoto University, Kyoto 606-8502 (Japan); Tomsk State Pedagogical University,634050 Tomsk (Russian Federation); Yeom, Dong-han [Yukawa Institute for Theoretical Physics,Kyoto University, Kyoto 606-8502 (Japan); Leung Center for Cosmology and Particle Astrophysics, National Taiwan University,Taipei 10617, Taiwan (China)

2014-12-24

We study the motion of thin-shell bubbles and their tunneling in anti de Sitter (AdS) background. We are interested in the case when the outside of a shell is a Schwarzschild-AdS space (false vacuum) and the inside of it is an AdS space with a lower vacuum energy (true vacuum). If a collapsing true vacuum bubble is created, classically it will form a Schwarzschild-AdS black hole. However, this collapsing bubble can tunnel to a bouncing bubble that moves out to spatial infinity. Then, although the classical causal structure of a collapsing true vacuum bubble has the singularity and the event horizon, quantum mechanically the wavefunction has support for a history without any singularity nor event horizon which is mediated by the non-perturbative, quantum tunneling effect. This may be regarded an explicit example that shows the unitarity of an asymptotic observer in AdS, while a classical observer who only follows the most probable history effectively lose information due to the formation of an event horizon.

Thin-shell bubbles and information loss problem in anti de Sitter background

International Nuclear Information System (INIS)

Sasaki, Misao; Yeom, Dong-han

2014-01-01

We study the motion of thin-shell bubbles and their tunneling in anti de Sitter (AdS) background. We are interested in the case when the outside of a shell is a Schwarzschild-AdS space (false vacuum) and the inside of it is an AdS space with a lower vacuum energy (true vacuum). If a collapsing true vacuum bubble is created, classically it will form a Schwarzschild-AdS black hole. However, this collapsing bubble can tunnel to a bouncing bubble that moves out to spatial infinity. Then, although the classical causal structure of a collapsing true vacuum bubble has the singularity and the event horizon, quantum mechanically the wavefunction has support for a history without any singularity nor event horizon which is mediated by the non-perturbative, quantum tunneling effect. This may be regarded an explicit example that shows the unitarity of an asymptotic observer in AdS, while a classical observer who only follows the most probable history effectively lose information due to the formation of an event horizon.

General and crevice corrosion study of the in-wall shielding materials for ITER vacuum vessel

Science.gov (United States)

Joshi, K. S.; Pathak, H. A.; Dayal, R. K.; Bafna, V. K.; Kimihiro, Ioki; Barabash, V.

2012-11-01

Vacuum vessel In-Wall Shield (IWS) will be inserted between the inner and outer shells of the ITER vacuum vessel. The behaviour of IWS in the vacuum vessel especially concerning the susceptibility to crevice of shielding block assemblies could cause rapid and extensive corrosion attacks. Even galvanic corrosion may be due to different metals in same electrolyte. IWS blocks are not accessible until life of the machine after closing of vacuum vessel. Hence, it is necessary to study the susceptibility of IWS materials to general corrosion and crevice corrosion under operations of ITER vacuum vessel. Corrosion properties of IWS materials were studied by using (i) Immersion technique and (ii) Electro-chemical Polarization techniques. All the sample materials were subjected to a series of examinations before and after immersion test, like Loss/Gain weight measurement, SEM analysis, and Optical stereo microscopy, measurement of surface profile and hardness of materials. After immersion test, SS 304B4 and SS 304B7 showed slight weight gain which indicate oxide layer formation on the surface of coupons. The SS 430 material showed negligible weight loss which indicates mild general corrosion effect. On visual observation with SEM and Metallography, all material showed pitting corrosion attack. All sample materials were subjected to series of measurements like Open Circuit potential, Cyclic polarization, Pitting potential, protection potential, Critical anodic current and SEM examination. All materials show pitting loop in OC2 operating condition. However, its absence in OC1 operating condition clearly indicates the activity of chloride ion to penetrate oxide layer on the sample surface, at higher temperature. The critical pitting temperature of all samples remains between 100° and 200°C.

Structural analysis of the ITER vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Sannazzaro, G.; Ioki, K.; Johnson, G.; Onozuka, M.; Utin, Y. [ITER Joint Work Site, Garching (Germany); Nelson, B. [Oak Ridge National Lab., TN (United States); Swanson, J. [USHT, Raytheon, Princeton (United States)

1998-07-01

The ITER Vacuum Vessel (VV) must withstand a large number of loading conditions including electromagnetic, seismic, operational and upset pressure, thermal and test loads. All of the loading conditions and load combinations have been categorized and classified to permit the allowable stress to be defined in accordance with the recommendations of the ASME code. The most severe loading conditions for the VV are the toroidal field coil fast discharge (TFCFD) and the load combination of seismic and electromagnetic loads due to a plasma vertical instability. The areas of high stress are the regions around the VV and the blanket supports, and the attachment of the ports to the main shell. In all of the loading conditions and load combinations the calculated stresses are below the allowable values. (authors)

Anomalous vacuum expectation values

International Nuclear Information System (INIS)

Suzuki, H.

1986-01-01

The anomalous vacuum expectation value is defined as the expectation value of a quantity that vanishes by means of the field equations. Although this value is expected to vanish in quantum systems, regularization in general produces a finite value of this quantity. Calculation of this anomalous vacuum expectation value can be carried out in the general framework of field theory. The result is derived by subtraction of divergences and by zeta-function regularization. Various anomalies are included in these anomalous vacuum expectation values. This method is useful for deriving not only the conformal, chiral, and gravitational anomalies but also the supercurrent anomaly. The supercurrent anomaly is obtained in the case of N = 1 supersymmetric Yang-Mills theory in four, six, and ten dimensions. The original form of the energy-momentum tensor and the supercurrent have anomalies in their conservation laws. But the modification of these quantities to be equivalent to the original one on-shell causes no anomaly in their conservation laws and gives rise to anomalous traces

Safety and operational aspects in in-situ electrical baking of large vacuum systems of Indus accelerators

International Nuclear Information System (INIS)

Bhatnagar, Prateek; Bhange, Nilesh; Joshi, Sujata; Sridhar, R.

2016-01-01

In order to achieve pressures in UHV (Ultra High Vacuum) range, the vacuum chambers and associated vacuum components, necessarily made of UHV compatible materials, should be baked sufficiently long enough so as to reduce outgassing rates. The baking period usually ranges from 48 hours to 72 hours for an electrical load of more than 30 kW per sector, in which baking temperatures, a characteristic parameter and specific to material, range from 150°C-180°C for Aluminium alloy and 250°C-300°C for SS (stainless steel). Indus accelerators vacuum installations include more than 300 m long vacuum chamber which are subjected to rigorous, standardized and labour intensive electrical baking procedure involving an intelligent ON-OFF distributed temperature control system with in-built defence of electrical safety and expandability as per the needs. The paper discusses various in built electrical safely features, operational aspects, work practices and challenges involved in accomplishing an interrupt free continuous electrical baking for distributed electrical load of more than 30 kW for a typical vacuum segment of Indus accelerator. (author)

HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SUMMARY OF COMBINED THERMAL AND OPERATING LOADS WITH SEISMIC ANALYSIS

Energy Technology Data Exchange (ETDEWEB)

MACKEY TC; DEIBLER JE; RINKER MW; JOHNSON KI; ABATT FG; KARRI NK; PILLI SP; STOOPS KL

2009-01-15

This report summarizes the results of the Double-Shell Tank Thermal and Operating Loads Analysis (TaLA) combined with the Seismic Analysis. This combined analysis provides a thorough, defensible, and documented analysis that will become a part of the overall analysis of record for the Hanford double-shell tanks (DSTs). The bases of the analytical work presented herein are two ANSYS{reg_sign} finite element models that were developed to represent a bounding-case tank. The TaLA model includes the effects of temperature on material properties, creep, concrete cracking, and various waste and annulus pressure-loading conditions. The seismic model considers the interaction of the tanks with the surrounding soil including a range of soil properties, and the effects of the waste contents during a seismic event. The structural evaluations completed with the representative tank models do not reveal any structural deficiencies with the integrity of the DSTs. The analyses represent 60 years of use, which extends well beyond the current date. In addition, the temperature loads imposed on the model are significantly more severe than any service to date or proposed for the future. Bounding material properties were also selected to provide the most severe combinations. While the focus of the analyses was a bounding-case tank, it was necessary during various evaluations to conduct tank-specific analyses. The primary tank buckling evaluation was carried out on a tank-specific basis because of the sensitivity to waste height, specific gravity, tank wall thickness, and primary tank vapor space vacuum limit. For this analysis, the occurrence of maximum tank vacuum was classified as a service level C, emergency load condition. The only area of potential concern in the analysis was with the buckling evaluation of the AP tank, which showed the current limit on demand of l2-inch water gauge vacuum to exceed the allowable of 10.4 inches. This determination was based on analysis at the

ALICE's first vacuum bakeout a success

CERN Multimedia

2007-01-01

At the beginning of April, the ALICE central beryllium beam pipe and absorber beam pipes were successfully conditioned. The installation and bakeout shell surround the beam pipe (lower left), running through the middle of the ITS and TPC. Notice the high-tech cooling system, an additional precaution to avoid overheating the ALICE detection equipment.One end of the vacuum sector during the bakeout and pure gas refill. It is unusual for a vacuum sector to end as it does in the middle of a non-accessible detector and made the installation and cabling of the bakeout equipment a more difficult procedure. Just before Easter, the first bakeout and NEG activation of experimental chambers in the LHC was carried out, followed by ultra pure gas refill. The bakeout consisted of externally heating the chambers under vacuum in order to lower their outgassing. This same heating process also activates the NEG, a coating on the inside surface of the beam vacuum chambers, which pumps the residual gas. ALICE's bakeout was pa...

Particle contamination in vacuum systems

International Nuclear Information System (INIS)

Martignac, J.; Bonin, B.; Henriot, C.; Poupeau, J.P.; Koltchakian, I.; Kocic, D.; Herbeaux, Ch.; Marx, J.P.

1996-01-01

Many vacuum devices, like RF cavities, are sensitive to particle contamination. This fact has motivated a considerable effort of cleanliness from the SRF community. The present paper reports the first results of a general study trying to identify the most contaminating steps during assembly and vacuum operation of the cavity. The steps investigated here are gasket assembly, evacuation and venting of the vacuum system, and operation of sputter ion pumps. (author)

Particle contamination in vacuum systems

International Nuclear Information System (INIS)

Martignac, J.; Bonin, B.; Henriot, C.; Poupeau, J.P.; Koltchakian, I.; Kocic, D.; Herbeaux, Ch.; Marx, J.P.

1996-01-01

Many vacuum devices, like RF cavities, are sensitive to particle contamination. This fact has motivated a considerable effort of cleanliness from the SRF community. The first results of a general study trying to identify the most contaminating steps during assembly and vacuum operation of the cavity is reported. The steps investigated here are gasket assembly, evacuation and venting of the vacuum system, and operation of sputter ion pumps. (author)

On the dynamics of relativistic multi-layer spherical shell systems

Energy Technology Data Exchange (ETDEWEB)

Gaspar, Merse E; Racz, Istvan, E-mail: merse@rmki.kfki.hu, E-mail: iracz@rmki.kfki.hu [RMKI, H-1121 Budapest, Konkoly Thege Miklos ut 29-33, Budapest (Hungary)

2011-04-21

The relativistic time evolution of multi-layer spherically symmetric shell systems-consisting of infinitely thin shells separated by vacuum regions-is examined. Whenever two shells collide the evolution is continued with the assumption that the collision is totally transparent. The time evolution of various multi-layer shell systems-comprising large number of shells thereby mimicking the behavior of a thick shell making it possible to study the formation of acoustic singularities-is analyzed numerically and compared in certain cases to the corresponding Newtonian time evolution. The analytic setup is chosen such that the developed code is capable of following the evolution even inside the black hole region. This, in particular, allowed us to investigate the mass inflation phenomenon in the chosen framework.

A dictionary between R-operators, on-shell graphs and Yangian algebras

Energy Technology Data Exchange (ETDEWEB)

Broedel, Johannes; Leeuw, Marius de; Rosso, Matteo [Institut für Theoretische Physik, Eidgenössische Technische Hochschule Zürich,Wolfgang-Pauli-Strasse 27, 8093 Zürich (Switzerland)

2014-06-27

We translate between different formulations of Yangian invariants relevant for the computation of tree-level scattering amplitudes in N=4 super-Yang–Mills theory. While the R-operator formulation allows to relate scattering amplitudes to structures well known from integrability, it can equally well be connected to the permutations encoded by on-shell graphs.

Analysis Bounding Double Shell Tank (DST) Performance for the Hanford Tank Waste Operation Simulator Case 2

International Nuclear Information System (INIS)

SMITH, D.F.

2002-01-01

The purpose of this analysis is to compare the latest Tank Farm Contractor Operation and Utilization Plan (HNF-SD-WM-SP-012, Rev. 3) ''Case 2'' operating scenarios with a previous bounding analysis for the Double-Shell Tank (DST) System in order to provide a technical assessment against the current set of DST System performance requirements. A later update to HNF-SD-WM-SP-012 (i.e., Rev. 3A), released in late December 2001, did not impact the results of this analysis. This analysis provides technical support for revising the Performance Requirements for the Double-Shell Tank System, HNF-2168, Rev. 3, used as the basis for defining performance requirements noted in System Specification for the Double-Shell Tank System, HNF-SD-WM-TRD-007. Rev. 1

HANFORD DOUBLE SHELL TANK (DST) THERMAL & SEISMIC PROJECT BUCKLING EVALUATION METHODS & RESULTS FOR THE PRIMARY TANKS

Energy Technology Data Exchange (ETDEWEB)

MACKEY TC; JOHNSON KI; DEIBLER JE; PILLI SP; RINKER MW; KARRI NK

2007-02-14

This report documents a detailed buckling evaluation of the primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office of Environment, Safety, and Health (ES&H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation of the aging waste facility (AWF) primary tank ventilation system. The current buckling review focuses on the following tasks: (1) Evaluate the potential for progressive I-bolt failure and the appropriateness of the safety factors that were used for evaluating local and global buckling. The analysis will specifically answer the following questions: (a) Can the EH-22 scenario develop if the vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? (b) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario can develop? (c) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario cannot develop? (2) Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations of tank loads, based on detailed finite element analysis. The analysis must account for the variation in design details and operating conditions between the different DSTs. The analysis must also address the imperfection sensitivity of the primary tank to buckling. (3) Perform a detailed buckling analysis to determine the maximum allowable differential pressure for each of the DST primary tanks at the current specified limits on waste temperature, height, and specific gravity. Based on the I-bolt loads analysis and the small deformations that are predicted at the unfactored limits on vacuum and axial loads, it is very unlikely that the EH-22 scenario (i.e., progressive I-bolt failure leading to global

Vacuum Technology

Energy Technology Data Exchange (ETDEWEB)

Biltoft, P J

2004-10-15

The environmental condition called vacuum is created any time the pressure of a gas is reduced compared to atmospheric pressure. On earth we typically create a vacuum by connecting a pump capable of moving gas to a relatively leak free vessel. Through operation of the gas pump the number of gas molecules per unit volume is decreased within the vessel. As soon as one creates a vacuum natural forces (in this case entropy) work to restore equilibrium pressure; the practical effect of this is that gas molecules attempt to enter the evacuated space by any means possible. It is useful to think of vacuum in terms of a gas at a pressure below atmospheric pressure. In even the best vacuum vessels ever created there are approximately 3,500,000 molecules of gas per cubic meter of volume remaining inside the vessel. The lowest pressure environment known is in interstellar space where there are approximately four molecules of gas per cubic meter. Researchers are currently developing vacuum technology components (pumps, gauges, valves, etc.) using micro electro mechanical systems (MEMS) technology. Miniature vacuum components and systems will open the possibility for significant savings in energy cost and will open the doors to advances in electronics, manufacturing and semiconductor fabrication. In conclusion, an understanding of the basic principles of vacuum technology as presented in this summary is essential for the successful execution of all projects that involve vacuum technology. Using the principles described above, a practitioner of vacuum technology can design a vacuum system that will achieve the project requirements.

Applicability assessment of plug weld to ITER vacuum vessel by crack propagation analysis

International Nuclear Information System (INIS)

Ohmori, Junji; Nakahira, Masataka; Takeda, Nobukazu; Shibanuma, Kiyoshi; Sago, Hiromi; Onozuka, Masanori

2006-03-01

In order to improve the fabricability of the vacuum vessel (VV) of International Thermonuclear Experimental Reactor (ITER), applicability of plug weld between VV outer shell and stiffening ribs/blanket support housings has been assessed using crack propagation analysis for the plug weld. The ITER VV is a double-wall structure of inner and outer shells with ribs and housings between the shells. For the fabrication of VV, ribs and housings are welded to outer shell after welding to inner shell. A lot of weld grooves should be adjusted for welding outer shell. The plug weld is that outer shells with slit at the weld region are set on ribs/housings then outer shells are welded to them by filling the slits with weld metal. The plug weld can allow larger tolerance of weld groove gap than ordinary butt weld. However, un-welded lengths parallel to outer sell surface remain in the plug weld region. It is necessary to evaluate the allowable un-welded length to apply the plug weld to ITER VV fabrication. For the assessment, the allowable un-welded lengths have been calculated by crack propagation analyses for load conditions, conservatively assuming the un-welded region is a crack. In the analyses, firstly allowable crack lengths are calculated from the stresses of the weld region. Then assuming initial crack length, crack propagation is calculated during operation period. Allowable initial crack lengths are determined on the condition that the propagated cracks should not exceed the allowable crack lengths. The analyses have been carried out for typical inboard straight region and inboard upper curved region with the maximum housing stress. The allowable initial cracks of ribs are estimated to be 8.8mm and 38mm for the rib and the housing, respectively, considering inspection error of 4.4mm. Plug weld between outer shell and ribs/housings could be applicable. (author)

"Flat-Fish" Vacuum Chamber

CERN Multimedia

CERN PhotoLab

1978-01-01

The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.

Fabrication of Ni@Ti core-shell nanoparticles by modified gas aggregation source

Science.gov (United States)

Hanuš, J.; Vaidulych, M.; Kylián, O.; Choukourov, A.; Kousal, J.; Khalakhan, I.; Cieslar, M.; Solař, P.; Biederman, H.

2017-11-01

Ni@Ti core-shell nanoparticles were prepared by a vacuum based method using the gas aggregation source (GAS) of nanoparticles. Ni nanoparticles fabricated in the GAS were afterwards coated by a Ti shell. The Ti shell was deposited by means of magnetron sputtering. The Ni nanoparticles were decelerated in the vicinity of the magnetron to the Ar drift velocity in the second deposition chamber. X-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy analysis of the nanoparticles showed the core-shell structure. It was shown that the thickness of the shell can be easily tuned by the process parameters with a maximum achieved thickness of the Ti shell ~2.5 nm. The core-shell structure was confirmed by the STEM analysis of the particles.

Vacuum mechatronics

Science.gov (United States)

Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

1989-01-01

The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

Charged shells in Lovelock gravity: Hamiltonian treatment and physical implications

International Nuclear Information System (INIS)

Dias, Goncalo A. S.; Gao, Sijie; Lemos, Jose P. S.

2007-01-01

Using a Hamiltonian treatment, charged thin shells, static and dynamic, in spherically symmetric spacetimes, containing black holes or other specific types of solutions, in d dimensional Lovelock-Maxwell theory are studied. The free coefficients that appear in the Lovelock theory are chosen to obtain a sensible theory, with a negative cosmological constant appearing naturally. Using an Arnowitt-Deser-Misner (ADM) description, one then finds the Hamiltonian for the charged shell system. Variation of the Hamiltonian with respect to the canonical coordinates and conjugate momenta, and the relevant Lagrange multipliers, yields the dynamic and constraint equations. The vacuum solutions of these equations yield a division of the theory into two branches, namely d-2k-1>0 (which includes general relativity, Born-Infeld type theories, and other generic gravities) and d-2k-1=0 (which includes Chern-Simons type theories), where k is the parameter giving the highest power of the curvature in the Lagrangian. There appears an additional parameter χ=(-1) k+1 , which gives the character of the vacuum solutions. For χ=1 the solutions, being of the type found in general relativity, have a black hole character. For χ=-1 the solutions, being of a new type not found in general relativity, have a totally naked singularity character. Since there is a negative cosmological constant, the spacetimes are asymptotically anti-de Sitter (AdS), and AdS when empty (for zero cosmological constant the spacetimes are asymptotically flat). The integration from the interior to the exterior vacuum regions through the thin shell takes care of a smooth junction, showing the power of the method. The subsequent analysis is divided into two cases: static charged thin shell configurations, and gravitationally collapsing charged dust shells (expanding shells are the time reversal of the collapsing shells). In the collapsing case, into an initially nonsingular spacetime with generic character or an empty

Electromagnetic forces on a metallic Tokamak vacuum vessel following a disruptive instability

International Nuclear Information System (INIS)

Eckhartt, D.

1979-04-01

During a 'hard' disruptive instability of a Tokamak plasma the current-carrying plasma is lost within a very short time, typically few milliseconds. If the plasma is contained in a metallic vacuum vessel, electric currents are set up in the vessel following the disappearance of the plasma current. These vessel currents together with the magnetic fields intersecting the vessel generate electromagnetic forces which appear as mechanical loads on the vessel. In the following note it is assumed that the vacuum vessel is surrounded by an 'outer equivalent' or 'flux-conserving' shell having a characteristic time of magnetic field penetration which is long compared to the time of existence of the vessel currents. This property defines the distribution of vessel current densities (and hence the load distribution) without referring to the exact mechanism or time sequence of events by which the plasma current is lost. Numerical examples of the electromagnetic force distribution from this model refer to parameters of the JET-device with the simplifying assumption of circular cross-sections for plasma current, vacuum vessel, and outer equivalent shell. (orig.)

HANFORD DOUBLE-SHELL TANK (DST) THERMAL and SEISMIC PROJECT-BUCKLING EVALUATION METHODS and RESULTS FOR THE PRIMARY TANKS

International Nuclear Information System (INIS)

Mackey, T.C.; Johnson, K.I.; Deibler, J.E.; Pilli, S.P.; Rinker, M.W.; Karri, N.K.

2007-01-01

This report documents a detailed buckling evaluation of the primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office of Environment, Safety, and Health (ES and H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation of the aging waste facility (AWF) primary tank ventilation system. The current buckling review focuses on the following tasks: (1) Evaluate the potential for progressive I-bolt failure and the appropriateness of the safety factors that were used for evaluating local and global buckling. The analysis will specifically answer the following questions: (a) Can the EH-22 scenario develop if the vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? (b) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario can develop? (c) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario cannot develop? (2) Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations of tank loads, based on detailed finite element analysis. The analysis must account for the variation in design details and operating conditions between the different DSTs. The analysis must also address the imperfection sensitivity of the primary tank to buckling. (3) Perform a detailed buckling analysis to determine the maximum allowable differential pressure for each of the DST primary tanks at the current specified limits on waste temperature, height, and specific gravity. Based on the I-bolt loads analysis and the small deformations that are predicted at the unfactored limits on vacuum and axial loads, it is very unlikely that the EH-22 scenario (i.e., progressive I-bolt failure leading to

Scroll vacuum pump

Energy Technology Data Exchange (ETDEWEB)

Morishita, Etsuo; Suganami, Takuya; Nishida, Mitsuhiro; Kitora, Yoshihisa; Yamamoto, Sakuei; Fujii, Kosaburo

1988-02-25

An effort is made to apply a scroll machine to development of a vacuum pump. In view of mechanical simplification and load patterns, the vacuum pump uses a rotating mechanism to produce paired vortices rotating around each center. Chip seal and atmospheric pressure are utilized for axial gap sealing while a spring and atmospheric pressure for the radial gap sealing. In both gaps, the sealing direction is stationary relative to the environment during rotation, making it much easier to achieve effective sealing as compared to oscillating pumps. Since the compression ratio is high in vacuum pumps, a zero top clearance form is adopted for the central portion of vortices and an gas release valve is installed in the rotating axis. A compact Oldham coupling with a small inertia force is installed behind the vortices to maintain the required phase relations between the vortices. These improvements result in a vacuum of 1 Pa for dry operation and 10/sup -2/ Pa for oil flooded operation of a single-stage scroll machine at 1800 rpm. (5 figs, 1 tab, 4 refs)

Vacuum considerations summary

International Nuclear Information System (INIS)

1977-01-01

The vacuum system for Heavy Ion Fusion machines can be divided according to pressure into 4 parts: (a) Ion Sources; (b) Linear Accelerators; (c) Circular Accelerators, Accumulators and Storage Rings; and (d) Reactors. Since ion sources will need rather conventional pumping arrangements and reactors will operate with greater pressures, depending on their mode of operation, only items b and c will be treated in this report. In particular, the vacuum system design will be suggested for the machines proposed by various scenarios arrived at during the workshop. High mass numbers will be assumed

Application of vacuum membrane distillation to lithium bromide absorption refrigeration system

Energy Technology Data Exchange (ETDEWEB)

Wang, Zanshe; Feng, Shiyu; Li, Yun [School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Gu, Zhaolin [School of Human Settlement and Civil Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

2009-11-15

Conventional generator in lithium bromide absorption refrigeration system is too bulky and heavy to be fitted into small scale device, and the temperature of the driving heater in the generator seems much higher than low grade energy such as regenerative energy or waste heat energy. In this paper, desorption of aqueous lithium bromide solution by vacuum membrane distillation process was presented. Hollow fiber membrane module made by polyvinylidene fluoride was used as desorption device of aqueous lithium bromide solution. Influencing factors of feed flux, feed temperature in lumen side and vacuum pressure in shell side were tested and analyzed with orthogonal test. The results showed that permeation flux of water vapor increased with the feed temperature increasing and the feed flux increasing in lumen side, and the permeation flux also went up along with absolute pressure drop in shell side. Feasibility and potential application analysis shows that the temperature of the driving heat was low and the volume and weight of the desorption device was light. In this study, vacuum membrane distillation to the lithium bromide absorption refrigeration system has proved to be an efficient and cheap desorption mode. (author)

Spent nuclear fuel project cold vacuum drying facility vacuum and purge system design description

Energy Technology Data Exchange (ETDEWEB)

IRWIN, J.J.

1998-11-30

This document provides the System Design Description (SDD) for the Cold Vacuum Drying Facility (CVDF) Vacuum and Purge System (VPS) . The SDD was developed in conjunction with HNF-SD-SNF-SAR-O02, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of Processing Systems (Garvin 1998), The HNF-SD-SNF-DRD-002, 1998, Cold Vacuum Drying Facility Design Requirements, and the CVDF Design Summary Report. The SDD contains general descriptions of the VPS equipment, the system functions, requirements and interfaces. The SDD provides references for design and fabrication details, operation sequences and maintenance. This SDD has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved.

Spent nuclear fuel project cold vacuum drying facility vacuum and purge system design description

International Nuclear Information System (INIS)

IRWIN, J.J.

1998-01-01

This document provides the System Design Description (SDD) for the Cold Vacuum Drying Facility (CVDF) Vacuum and Purge System (VPS) . The SDD was developed in conjunction with HNF-SD-SNF-SAR-O02, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of Processing Systems (Garvin 1998), The HNF-SD-SNF-DRD-002, 1998, Cold Vacuum Drying Facility Design Requirements, and the CVDF Design Summary Report. The SDD contains general descriptions of the VPS equipment, the system functions, requirements and interfaces. The SDD provides references for design and fabrication details, operation sequences and maintenance. This SDD has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

Transient heat transfer analysis of superconducting magnetic levitating flywheel rotor operating in vacuum

Energy Technology Data Exchange (ETDEWEB)

Mochida, A.; Kudo, K.; Higasa, H.

1999-07-01

In the present study, transient temperature rise is analyzed in a flywheel type power storage system operated in vacuum environment. The flywheel rotor is levitated by high-temperature-superconducting magnetic bearing to reduce the bearing loss. Though the superconductor is cooled by liquid nitrogen, the temperature of the whole system rises due to Joule heating in the coils of the bearings and the motor during the operation. If the temperature should reach the critical temperature of the permanent magnet used for the magnetic bearings after long time operation, the magnetic bearings lose their effect. The heat generated in the levitated rotor diffuses within it by heat conduction and finally emitted to its surrounding solid materials by thermal radiation from the rotor surfaces across vacuum layer. Numerical simulation is carried out calculating the transient radiative-conductive heat transfer and time-dependent profiles of temperature within the rotor are obtained. The results are compared with the experimentally obtained temperatures by measured a test model of 1kWh power storage and the measured profiles of the temperature rise of the rotor fit very well with the calculated ones. Using this simulation tool, the effects of the surface emissivity of the materials of the rotor and the stator, the temperature of the surrounding casings and the thermal conductivity of the materials on the temperature profiles in the system are estimated.

Technical specification for vacuum systems

International Nuclear Information System (INIS)

Khaw, J.

1987-01-01

The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10 -5 to 10 -11 Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing and designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components

Shiva and Argus target diagnostics vacuum systems

International Nuclear Information System (INIS)

Glaros, S.S.; Mayo, S.E.; Campbell, D.; Holeman, D.

1978-09-01

The normal operation of LLL's Argus and Shiva laser irradiation facilities demand a main vacuum system for the target chamber and a separate local vacuum system for each of the larger appendage dianostics. This paper will describe the Argus and Shiva main vacuum systems, their respective auxiliary vacuum systems and the individual diagnostics with their respective special vacuum requirements and subsequent vacuum systems. Our latest approach to automatic computer-controlled vacuum systems will be presented

Resistor cooling in a vacuum

International Nuclear Information System (INIS)

Crittenden, R.; Krider, J.

1987-01-01

This note describes thermal measurements which were done on a resistor operating both in air at one atmosphere pressure and in a vacuum of a few milliTorr. The motivation for this measurement was our interest in operating a BGO crystal-photomultiplier tube-base assembly in a vacuum, as a synchrotron radiation detector to tag electrons in the MT beam. We wished to determine what fraction of the total resistor power was dissipated by convection in air, in order to know whether there would be excessive heating of the detector assembly in a vacuum. 3 figs

Stability time of a DT-filled cryogenic ICF target in a high vacuum environment

International Nuclear Information System (INIS)

Ebey, P.S.; Hoffer, J.K.

1998-01-01

Following the successful pressure loading with DT of a thin-walled plastic inertial fusion target shell (such as those designed for use at the OMEGA facility at the University of Rochester's Laboratory for Laser Energetics (UR/LLE)), continual care must be taken to safeguard the shell from being exposed to unacceptable pressure differentials across its wall. In particular, once the DT has been condensed into a liquid or solid phase and the outside pressure has been reduced, the target must be maintained below some upper cutoff temperature such that the vapor pressure of the DT is below the bursting pressure for the shell. Through the process of β-decay the DT self-heats, but while the shell is in a high vacuum environment (P much-lt 0.8 Pa (6 mtorr) for the OMEGA layering sphere) there is only a negligible heat loss mechanism. This will cause the temperature to increase. A calculation has been done to estimate the rate of temperature increase of the loaded target under high vacuum conditions. A functional form for calculating the target's temperature increase given its starting temperature is presented. An overall result is that under high vacuum conditions the DT changes from a solid at 10 K to a liquid at 37 K (T c = 39.4 K) in about 19 minutes. This holding time is significantly less if the initial temperature is higher, the initial state is liquid, or the upper allowed temperature is lower. Simplifying assumptions which were made and their impact on interpreting the results of this calculation are discussed

Vacuum expectation values for four-fermion operators. Model estimates

International Nuclear Information System (INIS)

Zhitnitskij, A.R.

1985-01-01

Some simple models (a system with a heavy quark, the rarefied insatanton gas) are used to investigate the problem of factorizability. Characteristics of vacuum fluctuations responsible for saturation of four-fermion vacuum expectation values which are known phenomenologically are discussed. A qualitative agreement between the model and phenomenologic;l estimates has been noted

Vacuum expectation values of four-fermion operators. Model estimates

International Nuclear Information System (INIS)

Zhitnitskii, A.R.

1985-01-01

Simple models (a system with a heavy quark, a rarefied instanton gas) are used to study problems of factorizability. A discussion is given of the characteristics of the vacuum fluctuations responsible for saturation of the phenomenologically known four-fermion vacuum expectation values. Qualitative agreement between the model and phenomenological estimates is observed

ITER diagnostic system: Vacuum interface

Energy Technology Data Exchange (ETDEWEB)

Patel, K.M., E-mail: Kaushal.Patel@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Udintsev, V.S.; Hughes, S.; Walker, C.I.; Andrew, P.; Barnsley, R.; Bertalot, L. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Drevon, J.M. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Encheva, A. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France); Kashchuk, Y. [Institution “PROJECT CENTER ITER”, 1, Akademika Kurchatova pl., Moscow (Russian Federation); Maquet, Ph. [Bertin Technologies, BP 22, 13762 Aix-en Provence cedex 3 (France); Pearce, R.; Taylor, N.; Vayakis, G.; Walsh, M.J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-Lez-Durance (France)

2013-10-15

Diagnostics play an essential role for the successful operation of the ITER tokamak. They provide the means to observe control and to measure plasma during the operation of ITER tokamak. The components of the diagnostic system in the ITER tokamak will be installed in the vacuum vessel, in the cryostat, in the upper, equatorial and divertor ports, in the divertor cassettes and racks, as well as in various buildings. Diagnostic components that are placed in a high radiation environment are expected to operate for the life of ITER. There are approx. 45 diagnostic systems located on ITER. Some diagnostics incorporate direct or independently pumped extensions to maintain their necessary vacuum conditions. They require a base pressure less than 10{sup −7} Pa, irrespective of plasma operation, and a leak rate of less than 10{sup −10} Pa m{sup 3} s{sup −1}. In all the cases it is essential to maintain the ITER closed fuel cycle. These directly coupled diagnostic systems are an integral part of the ITER vacuum containment and are therefore subject to the same design requirements for tritium and active gas confinement, for all normal and accidental conditions. All the diagnostics, whether or not pumped, incorporate penetration of the vacuum boundary (i.e. window assembly, vacuum feedthrough etc.) and demountable joints. Monitored guard volumes are provided for all elements of the vacuum boundary that are judged to be vulnerable by virtue of their construction, material, load specification etc. Standard arrangements are made for their construction and for the monitoring, evacuating and leak testing of these volumes. Diagnostic systems are incorporated at more than 20 ports on ITER. This paper will describe typical and particular arrangements of pumped diagnostic and monitored guard volume. The status of the diagnostic vacuum systems, which are at the start of their detailed design, will be outlined and the specific features of the vacuum systems in ports and extensions

ITER diagnostic system: Vacuum interface

International Nuclear Information System (INIS)

Patel, K.M.; Udintsev, V.S.; Hughes, S.; Walker, C.I.; Andrew, P.; Barnsley, R.; Bertalot, L.; Drevon, J.M.; Encheva, A.; Kashchuk, Y.; Maquet, Ph.; Pearce, R.; Taylor, N.; Vayakis, G.; Walsh, M.J.

2013-01-01

Diagnostics play an essential role for the successful operation of the ITER tokamak. They provide the means to observe control and to measure plasma during the operation of ITER tokamak. The components of the diagnostic system in the ITER tokamak will be installed in the vacuum vessel, in the cryostat, in the upper, equatorial and divertor ports, in the divertor cassettes and racks, as well as in various buildings. Diagnostic components that are placed in a high radiation environment are expected to operate for the life of ITER. There are approx. 45 diagnostic systems located on ITER. Some diagnostics incorporate direct or independently pumped extensions to maintain their necessary vacuum conditions. They require a base pressure less than 10 −7 Pa, irrespective of plasma operation, and a leak rate of less than 10 −10 Pa m 3 s −1 . In all the cases it is essential to maintain the ITER closed fuel cycle. These directly coupled diagnostic systems are an integral part of the ITER vacuum containment and are therefore subject to the same design requirements for tritium and active gas confinement, for all normal and accidental conditions. All the diagnostics, whether or not pumped, incorporate penetration of the vacuum boundary (i.e. window assembly, vacuum feedthrough etc.) and demountable joints. Monitored guard volumes are provided for all elements of the vacuum boundary that are judged to be vulnerable by virtue of their construction, material, load specification etc. Standard arrangements are made for their construction and for the monitoring, evacuating and leak testing of these volumes. Diagnostic systems are incorporated at more than 20 ports on ITER. This paper will describe typical and particular arrangements of pumped diagnostic and monitored guard volume. The status of the diagnostic vacuum systems, which are at the start of their detailed design, will be outlined and the specific features of the vacuum systems in ports and extensions will be described

Algorithm for study on the stressed-strained state of thermonuclear device vacuum chambers under dynamic loads

International Nuclear Information System (INIS)

Zhuravleva, A.M.; Litvinov, V.B.

1982-01-01

The problem of dynamic analysis of stressed-strained state of vacuum chambers is vital for large thermonuclear devices during the stall of the plasma-filament apd other tpansitional operation regimes when loading for a chamber are nonstationary. To plot a mathematical model the design of the vacuum chamber is discreted on the basis of the method of final elements. To approximate vacuum shell, a plate triangular element with 3 joint points and 5 parameters in the joint is used. It is obtained due to the unity of the bemded element and the element for the flat problem. To investigate nonstationary oscillations of vacuum chambers discreted on the basis of the method of final elements, it is suggested to use the numeric conversion of the Japlace transformation. On the basis of the algorithm suggested a program of numerical function conversion is developed. Test calculations have shown a good stability of the algorithm when selecting the values of transformation parameter in the range of lower intrinsic system frequencies. The advantage of the above method is in the fact that the time-structure shift function is found instantly in the form of the series for the whole time interval and does not require temporary steps, which bring about large expenses of counting time and error accumulation

R&D ERL: Vacuum

Energy Technology Data Exchange (ETDEWEB)

Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.

2010-01-01

The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the {approx}10{sup -9} torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2{sup o}K is reduced to low 10{sup -11} torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The

Past, Present and Future of Linac 2 Vacuum System

CERN Document Server

Mahner, E

2011-01-01

This note aims to review the past, present, and future operation of CERN's Linac 2 vacuum system. The machine vacuum system layout with its major components is summarized. Operational problems arising in 2006 yielded to a leak test campaign of the whole machine, which detected a new, major leak on tank 3. Details about the mitigation of this leak are described as well as additional diagnostics installed during shutdown 2006/07. The pressure evolution of the most critical vacuum sector is analyzed. A statistics of vacuum system faults observed since 2000 is presented and compared with other systems. Finally, a perspective for the vacuum system operation until 2017/18 is outlined.

Enhancing Ethanol Production by Fermentation Using Saccharomyces cereviseae under Vacuum Condition in Batch Operation

Directory of Open Access Journals (Sweden)

A Abdullah

2012-04-01

Full Text Available Ethanol is one of renewable energy, which considered being an excellent alternativeclean-burning fuel to replaced gasoline. In fact, the application of ethanol as fuel still blended withgasoline. The advantages of using ethanol as fuel are that the raw material mostly from renewableresources and the product has low emission which means environmental friendly. Ethanol can beproduced by fermentation of sugars (glucose/fructose. The constraint in the ethanol fermentationbatch or continuous process is the ethanol product inhibition. Inhibition in ethanol productivityand cell growth can be overcome by taking the product continuously from the fermentor. Theprocess can be done by using a vacuum fermentation. The objective of this research is toinvestigate the effect of pressure and glucose concentration in ethanol fermentation. The researchwas conducted in laboratory scale and batch process. Equipment consists of fermentor withvacuum system. The observed responses were dried cells of yeast, concentration of glucose, andconcentration of ethanol. Observations were made every 4 hours during a day of experiment. Theresults show that the formation of ethanol has a growth-associated product characteristic undervacuum operation. Vacuum condition can increase the cell formation productivity and the ethanolformation, as it is compared with fermentation under atmospheric condition. The maximum cellsproductivity and ethanol formation in batch operation under vacuum condition was reached at166.6 mmHg of pressure. The maximum numbers of cells and ethanol formation was reached at141.2 mm Hg of pressure. High initial glucose concentration significantly can affect the productivityand the yield of ethanol.

Spent Nuclear Fuel (SNF) Project Cold Vacuum Drying (CVD) Facility Operations Manual

International Nuclear Information System (INIS)

IRWIN, J.J.

2000-01-01

The mission of the Spent Nuclear Fuel (SNF) Project Cold Vacuum Drying Facility (CVDF) is to achieve the earliest possible removal of free water from Multi-Canister Overpacks (MCOs). The MCOs contain metallic uranium SNF that have been removed from the 100K Area fuel storage water basins (i.e., the K East and K West Basins) at the US. Department of Energy Hanford Site in Southeastern Washington state. Removal of free water is necessary to halt water-induced corrosion of exposed uranium surfaces and to allow the MCOs and their SNF payloads to be safely transported to the Hanford Site 200 East Area and stored within the SNF Project Canister Storage Building (CSB). The CVDF is located within a few hundred yards of the basins, southwest of the 165KW Power Control Building and the 105KW Reactor Building. The site area required for the facility and vehicle circulation is approximately 2 acres. Access and egress is provided by the main entrance to the 100K inner area using existing roadways. The CVDF will remove free. water from the MCOs to reduce the potential for continued fuel-water corrosion reactions. The cold vacuum drying process involves the draining of bulk water from the MCO and subsequent vacuum drying. The MCO will be evacuated to a pressure of 8 torr or less and backfilled with an inert gas (helium). The MCO will be sealed, leak tested, and then transported to the CSB within a sealed shipping cask. (The MCO remains within the same shipping Cask from the time it enters the basin to receive its SNF payload until it is removed from the Cask by the CSB MCO handling machine.) The CVDF subproject acquired the required process systems, supporting equipment, and facilities. The cold vacuum drying operations result in an MCO containing dried fuel that is prepared for shipment to the CSB by the Cask transportation system. The CVDF subproject also provides equipment to dispose of solid wastes generated by the cold vacuum drying process and transfer process water removed

On the spectral properties of Dirac operators with electrostatic delta-shell interactions

Czech Academy of Sciences Publication Activity Database

Behrndt, J.; Exner, Pavel; Holzmann, M.; Lotoreichik, Vladimir

2018-01-01

Roč. 111, č. 3 (2018), s. 47-78 ISSN 0021-7824 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : Dirac operator * self-adjoint extension * shell interaction * spectral properties Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 1.802, year: 2016

Analysis of effective electrical parameters for CFETR vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Liu, Xufeng; Xu, Weiwei, E-mail: wwxu@ipp.ac.cn; Du, Shuangsong; Zheng, Jinxing

2016-11-15

Highlights: • The eddy current distribution and variation of CFETR vacuum vessel during plasma disruption have been calculated. • Effective electrical parameters can be derived from the eddy current characters. • The method for eddy current and effective electrical parameters is suit for the complex shell with arbitrary shape. - Abstract: The electrical parameters of CFETR (China Fusion Engineering Test Reactor) vacuum vessel are very important to the design of control system and power supply system. Effective electrical parameters are relevant to the dynamic of eddy current. For complex structure, the distribution of eddy current can’t be obtained by analytical form. A method is presented to solve the eddy current of the vacuum vessel in this paper. The effective electrical parameters can be got from the eddy current distribution and variation. The time constant of the CFETR vacuum vessel is derived from the decay characteristics of the eddy current. And the effective resistance and inductance can be derived from the viewpoint of energy for a certain distribution of eddy current.

He leaks in the CERN LHC beam vacuum chambers operating at cryogenic temperatures

CERN Document Server

Baglin, V

2007-01-01

The 27 km long large hadron collider (LHC), currently under construction at CERN, will collide protons beam at 14 TeV in the centre of mass. In the 8 arcs, the superconducting dipoles and quadrupoles of the FODO cells operate with superfluid He at 1.9 K. In the 8 long straight sections, the cold bores of the superconducting magnets are held at 1.9 or 4.5 K. Thus, in the LHC, 75% of the beam tube vacuum chamber is cooled with He. In many areas of the machine, He leaks could appear in the beam tube. At cryogenic temperature, the gas condenses onto the cold bores or beam screens, and interacts with the circulating beam. He leaks creates a He front propagating along the vacuum chambers, which might cause magnet quench. We discuss the consequences of He leaks, the possible means of detections, the strategies to localise them and the methods to measure their size.

Evaluation of CBA first string full cell vacuum system

International Nuclear Information System (INIS)

Foerster, C.L.; Briggs, J.; Christianson, C.; Stattel, P.

1983-01-01

The CBA (Colliding Beam Accelerator, formerly known as ISABELLE) Full Cell Magnet System consisting of six superconducting dipole magnets and two superconducting quadrupole magnets requires two separate vacuum systems. One, known as beam vacuum operates below 3 x 10 -11 Torr and the other, known as insulating vacuum, operates at less than 10 -7 Torr to isolate cryo circuits from atmosphere and from the uhv beam tubes. The uhv bore tube is isolated from the 4.0 0 K magnet by thirty-six (36) layers of superinsulation and insulating vacuum. Heat load measurements on the bore tube have been completed and found to agree with data obtained in smaller controlled experiments. Measurements of helium, accumulated on cryogenic pumped charcoal panels over many weeks, have verified sensitive helium mass spectrometer leak detection methods for vacuum integrity, providing sound design of the welded complex. The Full Cell was assembled and operated under conditions that would exist in the completed machine. Pressures below 2 x 10 -11 Torr beam vacuum requirement and below 2 x 10 -7 Torr insulating vacuum, were routinely achieved during all phases of the Full Cell operation and support systems testing

Plasma-column instabilities in a reversed-field pinch without a shell

Energy Technology Data Exchange (ETDEWEB)

Schmid, P.G.

1988-01-01

Plasma column instabilities in a Reversed Field Pinch (RFP) without a shell were investigated in the Colorado Reversatron RFP. The Reversatron RFP (aspect ration R/a = 50 cm/8cm) is a toroidal plasma containment device consisting of a vacuum chamber, a thick conducting shell, modular shells, magnetic field producing coils and diagnostics to characterize the plasma. RFP discharges were set up in the Reversatron in three different experimental configurations: with a thick conducting shell, with a modular shell and with no shell. In two of the configurations, a shell enclosed the plasma column to provide some plasma stability. A vertical magnetic field provided equilibrium in experiments without a shell. Data from discharges without a shell indicated that the plasma duration was greatly reduced and the plasma resistance increased compared to the discharges with a thick shell. Plasma position probes indicated large plasma centriod displacements corresponding to a n = 1 and a n = 3 kink coincident with the peak of the plasma current and the start of a discharge termination phase. The modular shell lengthened the discharge duration and lowered the plasma resistance to values intermediate between the plasma with a thick shell and the plasma with no shell. The modular shell suppressed the large plasma column displacements observed in the RFP plasma without a shell.

Plasma-column instabilities in a reversed-field pinch without a shell

International Nuclear Information System (INIS)

Schmid, P.G.

1988-01-01

Plasma column instabilities in a Reversed Field Pinch (RFP) without a shell were investigated in the Colorado Reversatron RFP. The Reversatron RFP (aspect ration R/a = 50 cm/8cm) is a toroidal plasma containment device consisting of a vacuum chamber, a thick conducting shell, modular shells, magnetic field producing coils and diagnostics to characterize the plasma. RFP discharges were set up in the Reversatron in three different experimental configurations: with a thick conducting shell, with a modular shell and with no shell. In two of the configurations, a shell enclosed the plasma column to provide some plasma stability. A vertical magnetic field provided equilibrium in experiments without a shell. Data from discharges without a shell indicated that the plasma duration was greatly reduced and the plasma resistance increased compared to the discharges with a thick shell. Plasma position probes indicated large plasma centriod displacements corresponding to a n = 1 and a n = 3 kink coincident with the peak of the plasma current and the start of a discharge termination phase. The modular shell lengthened the discharge duration and lowered the plasma resistance to values intermediate between the plasma with a thick shell and the plasma with no shell. The modular shell suppressed the large plasma column displacements observed in the RFP plasma without a shell

HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT BUCKLING EVALUATION METHODS AND RESULTS FOR THE PRIMARY TANKS

Energy Technology Data Exchange (ETDEWEB)

MACKEY TC; JOHNSON KI; DEIBLER JE; PILLI SP; RINKER MW; KARRI NK

2009-01-14

This report documents a detailed buckling evaluation of the primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office of Environment, Safety, and Health (ES&H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation of the aging waste facility (AWF) primary tank ventilation system. The current buckling review focuses on the following tasks: (1) Evaluate the potential for progressive anchor bolt failure and the appropriateness of the safety factors that were used for evaluating local and global buckling. The analysis will specifically answer the following questions: (a) Can the EH-22 scenario develop if the vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? (b) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario can develop? (c) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario cannot develop? (2) Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations of tank loads based on detailed finite element analysis. The analysis must account for the variation in design details and operating conditions between the different DSTs. The analysis must also address the imperfection sensitivity of the primary tank to buckling. (3) Perform a detailed buckling analysis to determine the maximum allowable differential pressure for each of the DST primary tanks at the current specified limits on waste temperature, height, and specific gravity. Based on the concrete anchor bolt loads analysis and the small deformations that are predicted at the unfactored limits on vacuum and axial loads, it is very unlikely that the EH-22 scenario (i.e., progressive anchor bolt

HANFORD DOUBLE-SHELL TANK THERMAL AND SEISMIC PROJECT-BUCKLING EVALUATION METHODS AND RESULTS FOR THE PRIMARY TANKS

International Nuclear Information System (INIS)

Mackey, T.C.; Johnson, K.I.; Deibler, J.E.; Pilli, S.P.; Rinker, M.W.; Karri, N.K.

2009-01-01

This report documents a detailed buckling evaluation of the primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office of Environment, Safety, and Health (ES and H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation of the aging waste facility (AWF) primary tank ventilation system. The current buckling review focuses on the following tasks: (1) Evaluate the potential for progressive anchor bolt failure and the appropriateness of the safety factors that were used for evaluating local and global buckling. The analysis will specifically answer the following questions: (a) Can the EH-22 scenario develop if the vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? (b) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario can develop? (c) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario cannot develop? (2) Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations of tank loads based on detailed finite element analysis. The analysis must account for the variation in design details and operating conditions between the different DSTs. The analysis must also address the imperfection sensitivity of the primary tank to buckling. (3) Perform a detailed buckling analysis to determine the maximum allowable differential pressure for each of the DST primary tanks at the current specified limits on waste temperature, height, and specific gravity. Based on the concrete anchor bolt loads analysis and the small deformations that are predicted at the unfactored limits on vacuum and axial loads, it is very unlikely that the EH-22 scenario (i.e., progressive anchor

Point-like structure and off-shell dual strings

International Nuclear Information System (INIS)

Green, M.B.

1977-01-01

It is argued that in a consistent off-shell dual formalism the amplitude for the emission of a scalar off-shell state by a string consists of two components. One of these contains the particle poles in the off-shell leg and the other is intimately related to the insertion of a point-like energy density on the string. As a result, the amplitude for a string to emit a zero momentum scalar state into the vacuum (which may be relevant for spontaneous symmetry breaking) is described by the amplitude for a finite fraction of the energy in the string to collapse to a spatial point at some time (this fraction and its space-time position being integrated over). The off-shell amplitudes have an elegant formulation in terms of a set of 'confined modes' which can be assigned quark flavour quantum numbers to reproduce the Chan-Paton scheme. It is suggested that the dual model be modified by allowing for the coupling of scalar closed strings to the vacuum and the resulting effect on the space-time structure of dual Green functions is described. It is found that even the emission of a single zero-momentum closed string modifies the elastic amplitude in a significant manner, leading to a power-behaved fixed-angle cross section in contrast to the usual exponential decrease of the dual model. This arises from point-like scattering between energy densities accumulating in the colliding strings. The relationship between the fixed angle and Regge limits is discussed. The fixed angle behaviour is found to be the asymptotic limit in momentum transfer of a fixed pole that arises in the Regge limit. (Auth.)

Thick SS316 materials TIG welding development activities towards advanced fusion reactor vacuum vessel applications

Science.gov (United States)

Kumar, B. Ramesh; Gangradey, R.

2012-11-01

Advanced fusion reactors like ITER and up coming Indian DEMO devices are having challenges in terms of their materials design and fabrication procedures. The operation of these devices is having various loads like structural, thermo-mechanical and neutron irradiation effects on major systems like vacuum vessel, divertor, magnets and blanket modules. The concept of double wall vacuum vessel (VV) is proposed in view of protecting of major reactor subsystems like super conducting magnets, diagnostic systems and other critical components from high energy 14 MeV neutrons generated from fusion plasma produced by D-T reactions. The double walled vacuum vessel is used in combination with pressurized water circulation and some special grade borated steel blocks to shield these high energy neutrons effectively. The fabrication of sub components in VV are mainly used with high thickness SS materials in range of 20 mm- 60 mm of various grades based on the required protocols. The structural components of double wall vacuum vessel uses various parts like shields, ribs, shells and diagnostic vacuum ports. These components are to be developed with various welding techniques like TIG welding, Narrow gap TIG welding, Laser welding, Hybrid TIG laser welding, Electron beam welding based on requirement. In the present paper the samples of 20 mm and 40 mm thick SS 316 materials are developed with TIG welding process and their mechanical properties characterization with Tensile, Bend tests and Impact tests are carried out. In addition Vickers hardness tests and microstructural properties of Base metal, Heat Affected Zone (HAZ) and Weld Zone are done. TIG welding application with high thick SS materials in connection with vacuum vessel requirements and involved criticalities towards welding process are highlighted.

Thick SS316 materials TIG welding development activities towards advanced fusion reactor vacuum vessel applications

International Nuclear Information System (INIS)

Kumar, B Ramesh; Gangradey, R

2012-01-01

Advanced fusion reactors like ITER and up coming Indian DEMO devices are having challenges in terms of their materials design and fabrication procedures. The operation of these devices is having various loads like structural, thermo-mechanical and neutron irradiation effects on major systems like vacuum vessel, divertor, magnets and blanket modules. The concept of double wall vacuum vessel (VV) is proposed in view of protecting of major reactor subsystems like super conducting magnets, diagnostic systems and other critical components from high energy 14 MeV neutrons generated from fusion plasma produced by D-T reactions. The double walled vacuum vessel is used in combination with pressurized water circulation and some special grade borated steel blocks to shield these high energy neutrons effectively. The fabrication of sub components in VV are mainly used with high thickness SS materials in range of 20 mm- 60 mm of various grades based on the required protocols. The structural components of double wall vacuum vessel uses various parts like shields, ribs, shells and diagnostic vacuum ports. These components are to be developed with various welding techniques like TIG welding, Narrow gap TIG welding, Laser welding, Hybrid TIG laser welding, Electron beam welding based on requirement. In the present paper the samples of 20 mm and 40 mm thick SS 316 materials are developed with TIG welding process and their mechanical properties characterization with Tensile, Bend tests and Impact tests are carried out. In addition Vickers hardness tests and microstructural properties of Base metal, Heat Affected Zone (HAZ) and Weld Zone are done. TIG welding application with high thick SS materials in connection with vacuum vessel requirements and involved criticalities towards welding process are highlighted.

Greenhouse Effect: Temperature of a Metal Sphere Surrounded by a Glass Shell and Heated by Sunlight

Science.gov (United States)

Nguyen, Phuc H.; Matzner, Richard A.

2012-01-01

We study the greenhouse effect on a model satellite consisting of a tungsten sphere surrounded by a thin spherical, concentric glass shell, with a small gap between the sphere and the shell. The system sits in vacuum and is heated by sunlight incident along the "z"-axis. This development is a generalization of the simple treatment of the…

R and D ERL: Vacuum

International Nuclear Information System (INIS)

Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.

2010-01-01

The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the ∼10 -9 torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2 o K is reduced to low 10 -11 torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The cryostat vacuum thermally

The vacuum interlock system for the PETRA III beamlines

Energy Technology Data Exchange (ETDEWEB)

Degenhardt, Markus; Hahn, Ulrich; Hesse, Mathias; Schulte-Schrepping, Horst [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2008-07-01

The storage ring PETRA at DESY in Hamburg is being reconstructed into the third generation source for synchrotron radiation, PETRA III. The up to 100 m long beamlines are large UHV-systems that guide the synchrotron radiation from the storage ring to the experiments. Each beamline will be equipped with a vacuum interlock system to ensure the safe operation of the vacuum components. In particular the task of the vacuum interlock is to prevent faulty operations that can cause a ventilation of the vacuum system or a damage of vacuum components by the high power synchrotron radiation beam. The interlock system will be implemented as a PLC that is connected to a distributed input/output layer via a field bus system. As a specialty, the PLC will be realised as a soft-PLC running on a PC with a real time windows operating system. Another specialty is the visualisation and remote control of the vacuum interlock system by means of a website. At the beamline the interlock will be operated via a touch panel that displays the visualisation website. Additionally, the interlock can be remotely operated from any location by opening the visualisation website with a browser. The interlock is protected against unauthorised operation by a login page. All relevant interlock data will be fed into the existing network-based archive system.

Shell morphology and Raman spectra of epitaxial Ge-SixGe1-x and Si-SixGe1-x core-shell nanowires

Science.gov (United States)

Wen, Feng; Dillen, David C.; Kim, Kyounghwan; Tutuc, Emanuel

2017-06-01

We investigate the shell morphology and Raman spectra of epitaxial Ge-SixGe1-x and Si-SixGe1-x core-shell nanowire heterostructures grown using a combination of a vapor-liquid-solid (VLS) growth mechanism for the core, followed by in-situ epitaxial shell growth using ultra-high vacuum chemical vapor deposition. Cross-sectional transmission electron microscopy reveals that the VLS growth yields cylindrical Ge, and Si nanowire cores grown along the ⟨111⟩, and ⟨110⟩ or ⟨112⟩ directions, respectively. A hexagonal cross-sectional morphology is observed for Ge-SixGe1-x core-shell nanowires terminated by six {112} facets. Two distinct morphologies are observed for Si-SixGe1-x core-shell nanowires that are either terminated by four {111} and two {100} planes associated with the ⟨110⟩ growth direction or four {113} and two {111} planes associated with the ⟨112⟩ growth direction. We show that the Raman spectra of Si- SixGe1-x are correlated with the shell morphology thanks to epitaxial growth-induced strain, with the core Si-Si mode showing a larger red shift in ⟨112⟩ core-shell nanowires compared to their ⟨110⟩ counterparts. We compare the Si-Si Raman mode value with calculations based on a continuum elasticity model coupled with the lattice dynamic theory.

Vacuum technology in the chemical industry

CERN Document Server

Jorisch, Wolfgang

2015-01-01

Based on the very successful German edition and a seminar held by the German Engineers` Association (VDI) on a regular basis for years now, this English edition has been thoroughly updated and revised to reflect the latest developments. It supplies in particular the special aspects of vacuum technology, applied vacuum pump types and vacuum engineering in the chemical, pharmaceutical and process industry application-segments. The text includes chapters dedicated to latest European regulations for operating in hazardous zones with vacuum systems, methods for process pressure control and regulati

Upgrade of RHIC Vacuum Systems for High Luminosity Operation

CERN Document Server

Hseuh Hsiao Chaun; Smart, Loralie; Todd, Robert J; Weiss, Daniel

2005-01-01

With increasing ion beam intensity during recent RHIC operations, pressure rises of several decades were observed at most room temperature sections and at a few cold sections. The pressure rises are associated with electron multi-pacting, electron stimulated desorption and beam ion induced desorption and have been one of the major intensity and luminosity limiting factors for RHIC. Improvement of the warm sections has been carried out in the last few years. Extensive in-situ bakes, additional UHV pumping, anti-grazing ridges and beam tube solenoids have been implemented. Several hundred meters of NEG coated beam pipes have been installed and activated. Vacuum monitoring and interlock were enhanced to reduce premature beam aborts. Preliminary measures, such as pumping before cool down to reduce monolayer condensates, were also taken to suppress the pressure rises in the cold sections. The effectiveness of these measures in reducing the pressure rises during machine studies and during physics runs are discussed...

CERN Vacuum-System Activities during the Long Shutdown 1: The LHC Beam Vacuum

CERN Document Server

Baglin, V; Chiggiato, P; Jimenez, JM; Lanza, G

2014-01-01

After the Long Shutdown 1 (LS1) and the consolidation of the magnet bus bars, the CERN Large Hadron Collider (LHC) will operate with nominal beam parameters. Larger beam energy, beam intensities and luminosity are expected. Despite the very good performance of the beam vacuum system during the 2010-12 physics run (Run 1), some particular areas require attention for repair, consolidation and upgrade. Among the main activities, a large campaign aiming at the repair of the RF bridges of some vacuum modules is conducted. Moreover, consolidation of the cryogenic beam vacuum systems with burst disk for safety reasons is implemented. In addition, NEG cartridges, NEG coated inserts and new instruments for the vacuum system upgrade are installed. Besides these activities, repair, consolidation and upgrades of other beam equipment such as collimators, kickers and beam instrumentations are carried out. In this paper, the motivation and the description for such activities, together with the expected beam vacuum performa...

Filling the vacuum at LHCb

CERN Multimedia

Katarina Anthony

2013-01-01

Last month, the Vacuum, Surfaces and Coatings (VSC) group was tasked with an unusually delicate operation in the LHCb experiment cavern: removing the LHC beam pipe while keeping the sensitive Vertex Locator vacuum vessel (VELO) completely isolated from the action.   The VSC group seal off the VELO beam pipe with a flange. Image: Gloria Corti. LHCb’s VELO detector is one of the crown jewels of the experiment. With detector elements surrounded by a vacuum, it gets as close as 5 cm from the beam. Fantastic for physics, but difficult for all-important access. “Because of the sensitivity of the VELO detector and its proximity to the beam, the collaboration decided not to bake (see box) its portion of the beam pipe,” says Giulia Lanza (TE-VSC-LBV), the expert in charge of the beam vacuum operation. “Our group was therefore asked to remove the rest of the LHC beam pipe while keeping the VELO portion of the pipe completely isolated. This work...

Modeling of complex gas distribution systems operating under any vacuum conditions: Simulations of the ITER divertor pumping system

International Nuclear Information System (INIS)

Vasileiadis, N.; Tatsios, G.; Misdanitis, S.; Valougeorgis, D.

2016-01-01

Highlights: • An integrated s/w for modeling complex rarefied gas distribution systems is presented. • Analysis is based on kinetic theory of gases. • Code effectiveness is demonstrated by simulating the ITER divertor pumping system. • The present s/w has the potential to support design work in large vacuum systems. - Abstract: An integrated software tool for modeling and simulation of complex gas distribution systems operating under any vacuum conditions is presented and validated. The algorithm structure includes (a) the input geometrical and operational data of the network, (b) the definition of the fundamental set of network loops and pseudoloops, (c) the formulation and solution of the mass and energy conservation equations, (d) the kinetic data base of the flow rates for channels of any length in the whole range of the Knudsen number, supporting, in an explicit manner, the solution of the conservation equations and (e) the network output data (mainly node pressures and channel flow rates/conductance). The code validity is benchmarked under rough vacuum conditions by comparison with hydrodynamic solutions in the slip regime. Then, its feasibility, effectiveness and potential are demonstrated by simulating the ITER torus vacuum system with the six direct pumps based on the 2012 design of the ITER divertor. Detailed results of the flow patterns and paths in the cassettes, in the gaps between the cassettes and along the divertor ring, as well as of the total throughput for various pumping scenarios and dome pressures are provided. A comparison with previous results available in the literature is included.

Coherently Strained Si-SixGe1-x Core-Shell Nanowire Heterostructures.

Science.gov (United States)

Dillen, David C; Wen, Feng; Kim, Kyounghwan; Tutuc, Emanuel

2016-01-13

Coherently strained Si-SixGe1-x core-shell nanowire heterostructures are expected to possess a positive shell-to-core conduction band offset, allowing for quantum confinement of electrons in the Si core. We report the growth of epitaxial, coherently strained Si-SixGe1-x core-shell heterostructures through the vapor-liquid-solid mechanism for the Si core, followed in situ by the epitaxial SixGe1-x shell growth using ultrahigh vacuum chemical vapor deposition. The Raman spectra of individual nanowires reveal peaks associated with the Si-Si optical phonon mode in the Si core and the Si-Si, Si-Ge, and Ge-Ge vibrational modes of the SixGe1-x shell. The core Si-Si mode displays a clear red-shift compared to unstrained, bare Si nanowires thanks to the lattice mismatch-induced tensile strain, in agreement with calculated values using a finite-element continuum elasticity model combined with lattice dynamic theory. N-type field-effect transistors using Si-SixGe1-x core-shell nanowires as channel are demonstrated.

Design consideration on the synchrotron ultrahigh vacuum system

International Nuclear Information System (INIS)

Tsujikawa, H.; Chida, K.; Mizobuchi, A.; Miyahara, A.

1982-01-01

Ultrahigh vacuum production for the high-energy heavy-ion accelerator poses special problems concerning beam-gas molecule and beam-wall interactions. In this paper, summary of the TARN ultrahigh vacuum system and design criteria of the synchrotron ultrahigh vacuum system are presented. On-beam pressure of 4 x 10 -11 Torr is achieved in the TARN ultrahigh vacuum system, of which experiences through the construction and the operation are described and discussed. With emphasis on the application of newly developed technique in the fabrication of vacuum chamber and ultrahigh vacuum pump for the synchrotron ultrahigh vacuum system. (author)

All-metal vacuum chamber for the ZT-40 experiment

International Nuclear Information System (INIS)

Dike, R.S.; Downing, J.N.

1981-10-01

We discuss the design and fabrication of the all-metal vacuum chamber presently in use in the ZT-40 device. ZT-40 is the current experiment in the Los Alamos Reversed-Field Pinch (RFP) program. The new vessel, which replaces a ceramic one, is made of Inconel 625 and has major and minor diameters of 228 cm and 40 cm, respectively. It consists of 24 convoluted and straight sections welded into a single toroidal geometry. Presented are several design features showing diagnostic and vacuum port tubulations and thermal-electrical insulation isolating the unit from its conducting shell. We also discuss fabrication techniques and our procedure for cleaning and heat treatment designed to eliminate residual gas contamination in the Inconel material

Development of a vacuum superinsulation panel

Energy Technology Data Exchange (ETDEWEB)

Timm, H; Seefeldt, D; Nitze, C

1983-05-01

After completion of the investigations the vacuum-insulated panel is available as prototype. The aim of the investigations was to optimize and to finalize the vacuum superinsulation system with regard to a pressure-resistant, temperature-resistant thermal insulation of high efficiency. In this connection, particularly investigations with regard to vacuum-tight sealing, compression and evacuation of powder filling as well as special material investigations were performed. The application-specific utilization of the vacuum-insulated panel and the adjustment to special operational conditions can now be started. Application possibilities are at present seen in coverings or linings with high temperature and/or pressure requirements.

MicroShell Minimalist Shell for Xilinx Microprocessors

Science.gov (United States)

Werne, Thomas A.

2011-01-01

discovered in a routine but the system cannot be rebooted: Shell allows a skilled operator to directly edit the binary executable in memory. With some forethought, MicroShell code can be located in a different memory location from custom code, permitting the custom functionality to be overwritten at any time without stopping the controlling shell.

Accelerator tube vacuum conditions in the NSF tandem

International Nuclear Information System (INIS)

Groome, A.E.

1979-08-01

The Nuclear Structure Facility currently under construction at the Daresbury Laboratory contains a 30 MV tandem Van de Graaff accelerator with a modular design of accelerator tube. The vacuum system requirements are specified to limit beam loss due to charge-state-changing collisions in the residual gas. This report gives an assessment of some of the parameters affecting the vacuum pressure in an operational machine. Measurements are made of the vacuum conductance and outgassing rate of accelerator tube modules. An assessment is made of the effects of temperature rise, beam mis-steering and the presence of suppression magnets on the ultimate vacuum obtainable. Predictions are made of the pressure profile throughout the machine and consideration is given to operational problems such as tube conditioning and temporary loss of pumping. A schematic diagram of the tandem and its vacuum system is shown. (author)

SNS Cryogenic Test Facility Kinney Vacuum Pump Commissioning and Operation at 2 K

Energy Technology Data Exchange (ETDEWEB)

Degraff, Brian D. [ORNL; Howell, Matthew P. [ORNL; Kim, Sang-Ho [ORNL; Neustadt, Thomas S. [ORNL

2017-07-01

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) has built and commissioned an independent Cryogenic Test Facility (CTF) in support of testing in the Radio-frequency Test Facility (RFTF). Superconducting Radio-frequency Cavity (SRF) testing was initially conducted with the CTF cold box at 4.5 K. A Kinney vacuum pump skid consisting of a roots blower with a liquid ring backing pump was recently added to the CTF system to provide testing capabilities at 2 K. System design, pump refurbishment and installation of the Kinney pump will be presented. During the commissioning and initial testing period with the Kinney pump, several barriers to achieve reliable operation were experienced. Details of these lessons learned and improvements to skid operations will be presented. Pump capacity data will also be presented.

SNS Cryogenic Test Facility Kinney Vacuum Pump Commissioning and Operation at 2 K

Science.gov (United States)

DeGraff, B.; Howell, M.; Kim, S.; Neustadt, T.

2017-12-01

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) has built and commissioned an independent Cryogenic Test Facility (CTF) in support of testing in the Radio-frequency Test Facility (RFTF). Superconducting Radio-frequency Cavity (SRF) testing was initially conducted with the CTF cold box at 4.5 K. A Kinney vacuum pump skid consisting of a roots blower with a liquid ring backing pump was recently added to the CTF system to provide testing capabilities at 2 K. System design, pump refurbishment and installation of the Kinney pump will be presented. During the commissioning and initial testing period with the Kinney pump, several barriers to achieve reliable operation were experienced. Details of these lessons learned and improvements to skid operations will be presented. Pump capacity data will also be presented.

AA, vacuum tank for stochastic precooling

CERN Multimedia

CERN PhotoLab

1979-01-01

The vaccum tank in which the fast stochastic precooling kicker was installed. It is clad with heating jackets for bake-out to 200 deg C, indispensable for reaching the operational vacuum of 7E-11 Torr. Alain Poncet, responsible for AA vacuum, is looking on. See also 7910268, 8002234.

Use of vacuum in processing of uranium

International Nuclear Information System (INIS)

Saify, M.T.; Rai, C.B.; Singh, S.P.; Singh, R.P.

2003-01-01

Full text: Natural uranium in the form of metal and alloys with suitable heat treatment are being used as fuel in research and some of the power reactors. The fuel is required to satisfy the purity specification from the criteria of neutron economy, corrosion resistance and fabricability. Uranium and its alloys fall under the category of reactive materials. They readily react with atmospheric air to form oxides. If molten uranium is exposed to atmosphere, it reacts violently with atmospheric gases and moisture, leading to explosion in extreme cases. Hence, protective inert atmosphere or high vacuum is required in processing of the materials especially during the melting and casting operation. Vacuum is preferred for melting and remelting of metals and alloys to remove the gaseous and high volatile impurities, to improve the mechanical properties of the material. Also, under vacuum sound castings are produced for further processing by mechanical working or use in casting forms. The addition of reactive alloying elements in uranium is efficiently carried out under vacuum. The paper highlights vacuum systems deployed and applications of vacuum in various operations involved in the processing of uranium and its alloys

The theory of spherically symmetric thin shells in conformal gravity

Science.gov (United States)

Berezin, Victor; Dokuchaev, Vyacheslav; Eroshenko, Yury

The spherically symmetric thin shells are the nearest generalizations of the point-like particles. Moreover, they serve as the simple sources of the gravitational fields both in General Relativity and much more complex quadratic gravity theories. We are interested in the special and physically important case when all the quadratic in curvature tensor (Riemann tensor) and its contractions (Ricci tensor and scalar curvature) terms are present in the form of the square of Weyl tensor. By definition, the energy-momentum tensor of the thin shell is proportional to Diracs delta-function. We constructed the theory of the spherically symmetric thin shells for three types of gravitational theories with the shell: (1) General Relativity; (2) Pure conformal (Weyl) gravity where the gravitational part of the total Lagrangian is just the square of the Weyl tensor; (3) Weyl-Einstein gravity. The results are compared with these in General Relativity (Israel equations). We considered in detail the shells immersed in the vacuum. Some peculiar properties of such shells are found. In particular, for the traceless ( = massless) shell, it is shown that their dynamics cannot be derived from the matching conditions and, thus, is completely arbitrary. On the contrary, in the case of the Weyl-Einstein gravity, the trajectory of the same type of shell is completely restored even without knowledge of the outside solution.

2XIIB vacuum vessel: a unique design

International Nuclear Information System (INIS)

Hibbs, S.M.; Calderon, M.O.

1975-01-01

The 2XIIB mirror confinement experiment makes unique demands on its vacuum system. The confinement coil set encloses a cavity whose surface is comprised of both simple and compound curves. Within this cavity and at the core of the machine is the operating vacuum which is on the order of 10 -9 Torr. The vacuum container fits inside the cavity, presenting an inside surface suitable for titanium getter pumping and a means of removing the heat load imposed by incandescent sublimator wires. In addition, the cavity is constructed of nonmagnetic and nonconducting materials (nonmetals) to avoid distortion of the pulsed confinement field. It is also isolated from mechanical shocks induced in the machine's main structure when the coils are pulsed. This paper describes the design, construction, and operation of the 2XIIB high-vacuum vessel that has been performing successfully since early 1974

High-vacuum plasma pump

International Nuclear Information System (INIS)

Dorodnov, A.M.; Minajchev, V.E.; Miroshkin, S.I.

1980-01-01

The action of an electric-arc high-vacuum pump intended for evacuating the volumes in which the operation processes are followed by a high gas evolution is considered. The operation of the pump is based on the principle of controlling the getter feed according to the gas load and effect of plasma sorbtion pumping. The pump performances are given. The starting pressure is about 5 Pa, the limiting residual pressure is about 5x10 -6 Pa, the pumping out rate of nitrogen in the pressure range 5x10 -5 -5x10 -3 Pa accounts for about 4000 l/s, the power consumption comes to 6 kW. Analyzing the results of the test operation of the pump, it has been concluded that its principal advantages are the high starting pressure, controlled getter feed rate and possibility of pumping out the gases which are usually pumped out with difficulty. The operation reliability of the pump is defined mainly by reliable operation of the ignition system of the vacuum arc [ru

Structure of Nonlocal quark vacuum condensate in non-perturbative QCD vacuum

International Nuclear Information System (INIS)

Xiang Qianfei; Ma Weixing; Zhou Lijuan; Jiang Weizhou

2014-01-01

Based on the Dyson-Schwinger Equations (DSEs) with the rainbow truncation, and Operator Product Expansion, the structure of nonlocal quark vacuum condensate in QCD, described by quark self-energy functions A_f and B_f given usually by the solutions of the DSEs of quark propagator, is predicted numerically. We also calculate the local quark vacuum condensate, quark-gluon mixed local vacuum condensate, and quark virtuality. The self-energy functions A_f and B_f are given by the parameterized quark propagator functions σ_v"f (p"2) and σ_s"f (p"2) of Roberts and Williams, instead of the numerical solutions of the DSEs. Our calculated results are in reasonable agreement with those of QCD sum rules, Lattice QCD calculations, and instanton model predictions, although the resulting local quark vacuum condensate for light quarks, u, d, s, are a little bit larger than those of the above theoretical predictions. We think the differences are caused by model dependence. The larger of strange quark vacuum condensate than u, d quark is due to the s quark mass which is more larger than u, d quark masses. Of course, the Roberts-Williams parameterized quark propagator is an empirical formulism, which approximately describes quark propagation. (authors)

EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS (TBACT) DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEM SUPPORTING WASTE TRANSFER OPERATIONS

International Nuclear Information System (INIS)

Kelly, S.E.; Haass, C.C.; Kovach, J.L.; Turner, D.A.

2010-01-01

This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste through out the DST storage system to the Waste Treatment and Immobilization Plant (WTP).

EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS (TBACT) DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEMS SUPPORTING WASTE TRANSFER OPERATIONS

International Nuclear Information System (INIS)

Haas, C.C.; Kovach, J.L.; Kelly, S.E.; Turner, D.A.

2010-01-01

This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste through the DST storage system to the Waste Treatment and Immobilization Plant (WTP).

EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS (TBACT) DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEM SUPPORTING WASTE TRANSFER OPERATIONS

Energy Technology Data Exchange (ETDEWEB)

KELLY SE; HAASS CC; KOVACH JL; TURNER DA

2010-06-03

This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste throught the DST storage system to the Waste Treatment and Immobilization Plant (WTP).

EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS -TBACT- DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEMS SUPPORTING WASTE TRANSFER OPERATIONS

Energy Technology Data Exchange (ETDEWEB)

HAAS CC; KOVACH JL; KELLY SE; TURNER DA

2010-06-24

This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste through the DST storage system to the Waste Treatment and Immobilizaiton Plant (WTP).

Analysis of a cylindrical shell vibrating in a cylindrical fluid region

International Nuclear Information System (INIS)

Chung, H.; Turula, P.; Mulcahy, T.M.; Jendrzejczyk, J.A.

1976-08-01

Analytical and experimental methods are presented for evaluating the vibration characteristics of cylindrical shells such as the thermal liner of the Fast Flux Test Facility (FFTF) reactor vessel. The NASTRAN computer program is used to calculate the natural frequencies, mode shapes, and response to a harmonic loading of a thin, circular cylindrical shell situated inside a fluid-filled rigid circular cylinder. Solutions in a vacuum are verified with an exact solution method and the SAP IV computer code. Comparisons between analysis and experiment are made, and the accuracy and utility of the fluid-solid interaction package of NASTRAN is assessed

Vacuum Bellows, Vacuum Piping, Cryogenic Break, and Copper Joint Failure Rate Estimates for ITER Design Use

Energy Technology Data Exchange (ETDEWEB)

L. C. Cadwallader

2010-06-01

The ITER international project design teams are working to produce an engineering design in preparation for construction of the International Thermonuclear Experimental Reactor (ITER) tokamak. During the course of this work, questions have arisen in regard to safety barriers and equipment reliability as important facets of system design. The vacuum system designers have asked several questions about the reliability of vacuum bellows and vacuum piping. The vessel design team has asked about the reliability of electrical breaks and copper-copper joints used in cryogenic piping. Research into operating experiences of similar equipment has been performed to determine representative failure rates for these components. The following chapters give the research results and the findings for vacuum system bellows, power plant stainless steel piping (amended to represent vacuum system piping), cryogenic system electrical insulating breaks, and copper joints.

Water cooling thermal power measurement in a vacuum diffusion pump

Directory of Open Access Journals (Sweden)

Luís Henrique Cardozo Amorin

2012-04-01

Full Text Available Diffusion vacuum pumps are used both in industry and in laboratory science for high vacuum production. For its operation they must be refrigerated, and it is done by circulating water in open circuit. Considering that, vacuum systems stays operating by hours, the water consumption may be avoided if the diffusion vacuum pumps refrigeration were done in closed circuit. However, it is necessary to know the diffusion vacuum pump thermal power (the heat transferred to circulate water by time units to implement one of these and get in the refrigeration system dimension. In this paper the diffusion vacuum pump thermal power was obtained by measuring water flow and temperature variation and was calculated through the heat quantity variation equation time function. The thermal power value was 935,6 W, that is 397 W smaller and 35 W bigger than, respectively, the maximum and minimum diffusion pump thermal power suggested by its operation manual. This procedure have been shown useful to precisely determine the diffusion pump thermal power or of any other system that needs to be refrigerated in water closed circuit.

Role of vacuum in food preservation

International Nuclear Information System (INIS)

Bongirwar, D.R.

1997-01-01

Considerable progress has been made in the processing of foods using operations viz. drying, evaporation, distillation, concentration, centrifugation, filtration, irradiation, freeze drying, osmotic drying etc. to get ready to eat food, convenience food, pre cooked dried food. Vacuum technology in direct or indirect way has played a vital role in carrying out these food processing operations. The role of vacuum in getting these processes developed and its use in the development of these high quality products with respect to colour, flavour, texture and other attributes has been highlighted along with process details. (author)

Fabrication of full-size mock-up for 10° section of ITER vacuum vessel thermal shield

Energy Technology Data Exchange (ETDEWEB)

Kang, Dong Kwon [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Nam, Kwanwoo, E-mail: kwnam@nfri.re.kr [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Kang, Kyoung-O; Noh, Chang Hyun; Chung, Wooho [ITER Korea, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Lim, Kisuk; Kang, Youngkil [SFA Engineering Corp., Asan-si, Chungcheongnam-do 336-873 (Korea, Republic of); Hamlyn-Harris, Craig; Her, Namil; Robby, Hicks [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

2015-10-15

In this paper, a full-scale prototype fabrication for vacuum vessel thermal shield (VVTS) of ITER tokamak is described and test results are reported. All the manufacturing processes except for silver coating were performed in the fabrication of 10° section of VVTS. Pre-qualification test was conducted to compare the vertical and the horizontal welding positions. After shell welding, shell distortion was measured and adjusted. Shell thickness change was also measured after buffing process. Specially, VVTS ports need large bending and complex welding of shell and flange. Bending method for the complex and long cooling tube layout especially for the VVTS ports was developed in detail. Dimensional inspection of the fabricated mock-up was performed with a 3D laser scanner and the scanning data was analyzed.

Functions and Requirements for Automated Liquid Level Gauge Instruments in Single-Shell and Double-Shell Tank Farms

International Nuclear Information System (INIS)

CARPENTER, K.E.

1999-01-01

This functions and requirements document defines the baseline requirements and criteria for the design, purchase, fabrication, construction, installation, and operation of automated liquid level gauge instruments in the Tank Farms. This document is intended to become the technical baseline for current and future installation, operation and maintenance of automated liquid level gauges in single-shell and double-shell tank farms

242-A evaporator vacuum condenser system

International Nuclear Information System (INIS)

Smith, V.A.

1994-01-01

This document is written for the 242-A evaporator vacuum condenser system (VCS), describing its purpose and operation within the evaporator. The document establishes the operating parameters specifying pressure, temperature, flow rates, interlock safety features and interfacing sub-systems to support its operation

Changing MFTF vacuum environment

International Nuclear Information System (INIS)

Margolies, D.; Valby, L.

1982-12-01

The Mirror Fusion Test Facility (MFTF) vacuum vessel will be about 60m long and 10m in diameter at the widest point. The allowable operating densities range from 2 x 10 9 to 5 x 10 10 particles per cc. The maximum leak rate of 10 - 6 tl/sec is dominated during operation by the deliberately injected cold gas of 250 tl/sec. This gas is pumped by over 1000 square meters of cryopanels, external sorption pumps and getters. The design and requirements have changed radically over the past several years, and they are still not in final form. The vacuum system design has also changed, but more slowly and less radically. This paper discusses the engineering effort necessary to meet these stringent and changing requirements. Much of the analysis of the internal systems has been carried out using a 3-D Monte Carlo computer code, which can estimate time dependent operational pressures. This code and its use will also be described

Quantum vacuum energy in graphs and billiards

International Nuclear Information System (INIS)

Kaplan, L.

2010-01-01

The vacuum (Casimir) energy in quantum field theory is a problem relevant both to new nanotechnology devices and to dark energy in cosmology. The crucial question is the dependence of the energy on the system geometry. Despite much progress since the first prediction of the Casimir effect in 1948 and its subsequent experimental verification in simple geometries, even the sign of the force in nontrivial situations is still a matter of controversy. Mathematically, vacuum energy fits squarely into the spectral theory of second-order self-adjoint elliptic linear differential operators. Specifically one promising approach is based on the small-t asymptotics of the cylinder kernel e -t√(H) , where H is the self-adjoint operator under study. In contrast with the well-studied heat kernel e -tH , the cylinder kernel depends in a non-local way on the geometry of the problem. We discuss some results by the Louisiana-Oklahoma-Texas collaboration on vacuum energy in model systems, including quantum graphs and two-dimensional cavities. The results may shed light on general questions, including the relationship between vacuum energy and periodic or closed classical orbits, and the contribution to vacuum energy of boundaries, edges, and corners.

UHV testing of upgraded vacuum chambers for Indus-1

International Nuclear Information System (INIS)

Sindal, B.K.; Kumar, K.V.A.N.P.S.; Ramshiroman; Bhange, Nilesh; Yadav, D.P.; Sridhar, R.; Shukla, S.K.

2013-01-01

Indus-1 is a 450 MeV, 100 mA dedicated electron storage ring operating at pressure 10 -10 mbar range without beam and 10 -9 mbar range with beam using triode sputter ion pump (SIP) and titanium sublimation pump (TSP) combination. Indus-1 storage ring is presently working with six operational beam lines installed at three bending magnets. To accommodate two more beam lines and to reduce number of demountable joints, up-gradation of Indus-1 UHV system was planned. Salient features of upgraded vacuum system are bending magnet vacuum chambers with one extra port for additional beam line and straight section vacuum chambers with integrated TSP body. Half of the Indus-1 storage ring vacuum envelope with two bending magnet vacuum chamber and six straight section vacuum chambers were assembled with pumps, gauges etc, leak tested and tested for its UHV performance. Ultimate vacuum 5x10 -10 mbar with SIP and 2x10 -10 mbar after TSP pumping were achieved. Residual gas analyser (RGA) spectrum recorded for residual gas analysis indicated the imprints of a typical all metal UHV system having H 2 as major gas. This paper describes UHV testing of upgraded, newly fabricated vacuum chambers for Indus-1 storage ring. (author)

Exact two-loop vacuum polarization correction to the Lamb shift in hydrogenlike ions

International Nuclear Information System (INIS)

Plunien, G.; Beier, T.; Soff, G.

1998-01-01

We present a calculation scheme for the two-loop vacuum polarization correction of order α 2 to the Lamb shift of hydrogenlike high-Z atoms. The interaction with the external Coulomb field is taken into account to all orders in (Zα). By means of a modified potential approach the problem is reduced to the evaluation of effective one-loop vacuumpolarization potentials. An expression for the energy shift is deduced within the framework of partial wave decomposition performing appropriate subtractions. Exact results for the two-loop vacuum polarization contribution to the Lamb shift of K- and L-shell electron states in hydrogenlike lead and uranium are presented. (orig.)

Vacuum fusion of uranium

International Nuclear Information System (INIS)

Stohr, J.A.

1957-01-01

After having outlined that vacuum fusion and moulding of uranium and of its alloys have some technical and economic benefits (vacuum operations avoid uranium oxidation and result in some purification; precision moulding avoids machining, chip production and chemical reprocessing of these chips; direct production of the desired shape is possible by precision moulding), this report presents the uranium fusion unit (its low pressure enclosure and pumping device, the crucible-mould assembly, and the MF supply device). The author describes the different steps of cast production, and briefly comments the obtained results

TPX vacuum vessel transient thermal and stress conditions

International Nuclear Information System (INIS)

Feldshteyn, Y.; Dinkevich, S.; Feng, T.; Majumder, D.

1995-01-01

The TPX vacuum vessel provides the vacuum boundary for the plasma and the mechanical support for the internal components. Another function of the vacuum vessel is to contain neutron shielding water in the double wall space during normal operation. This double wall space serves as a heat reservoir for the entire vacuum vessel during bakeout. The vacuum vessel and the internal components are subjected to thermal stresses induced by a nonuniform temperature distribution within the structure during bakeout. A successful Conceptual Design Review in March 1993 has established superheated steam as the heating source of the vacuum vessel. A transient bakeout mode of the vacuum vessel and in-vessel components has been analyzed to evaluate transient period duration, proper temperature level, actual thermal stresses and performance of the steam equipment. Thermally, the vacuum vessel structure may be considered as an adiabatic system because it is perfectly insulated by the strong surrounding vacuum and multiple layers of superinsulation. Important aspects of the analysis are described herein

Electrostatically driven plasma hydrodynamic instability. I. The failure of vacuum-insulated, long wavelength laser fusion pellets

International Nuclear Information System (INIS)

Levermore, C.D.; Caflisch, R.E.; Wood, L.L.

1977-10-01

Longer wavelength (e.g., lambda = 10.5 μm) laser radiation generates relatively large fluxes of superthermal electrons that penetrate and preheat the cores of such pellets at early times in their implosion history, precluding their efficient subsequent compression. It has been proposed to separate the outermost shell of such pellets (onto which the laser light is directed) from its inner regions by a vacuum layer, thereby ''insulating'' these inner portions from superthermal electron degradation. We consider this proposal analytically and computationally, and find it to be questionable, due to the rapid penetration of the vacuum insulation layer by plasma streamers from the laser heated shells, which are accelerated to velocities of the order of those of the superthermal electrons by an electrostatic analog of the Rayleigh-Taylor instability. Results of such considerations are presented. The results developed also apply to a variety of formally similar phenomena, ranging from the relativistic edge of supernova photospheres to diode breakdown in REB machines

Continuous vacuum processing system for quartz crystal resonators

International Nuclear Information System (INIS)

Ney, R.J.; Hafner, E.

1979-01-01

An ultrahigh vacuum continuous cycle quartz crystal fabrication facility has been developed that assures an essentially contamination-free environment throughout the final manufacturing steps of the crystal unit. The system consists of five essentially tubular vacuum chambers that are interconnected through gate valves. The unplated crystal resonators, mounted in ceramic flatback frames and loaded on carrier trays, enter the vacuum system through an entrance air lock, are UV/ozone cleaned, baked at 300 0 C, plated to frequency, thermocompression sealed, and exit as completed crystal units through an exit air lock, while the bake, plate and seal chambers remain under continuous vacuum permanently. In-line conveyor belts are used, in conjunction with balanced vacuum manipulators, to move the resonator components to the various work stations. Unique high density, highly directional nozzle beam evaporation sources, capable of long term operation without reloading, are used for electroding the resonators simultaneously on both sides. The design goal for the system is a production rate of 200 units per 8 hour day; it is adaptable to automatic operation

Computational models for electromagnetic transients in ITER vacuum vessel, cryostat and thermal shield

International Nuclear Information System (INIS)

Alekseev, A.; Arslanova, D.; Belov, A.; Belyakov, V.; Gapionok, E.; Gornikel, I.; Gribov, Y.; Ioki, K.; Kukhtin, V.; Lamzin, E.; Sugihara, M.; Sychevsky, S.; Terasawa, A.; Utin, Y.

2013-01-01

A set of detailed computational models are reviewed that covers integrally the system “vacuum vessel (VV), cryostat, and thermal shields (TS)” to study transient electromagnetics (EMs) in the ITER machine. The models have been developed in the course of activities requested and supervised by the ITER Organization. EM analysis is enabled for all ITER operational scenarios. The input data are derived from results of DINA code simulations. The external EM fields are modeled accurate to the input data description. The known magnetic shell approach can be effectively applied to simulate thin-walled structures of the ITER machine. Using an integral–differential formulation, a single unknown is determined within the shells in terms of the vector electric potential taken only at the nodes of a finite-element (FE) mesh of the conducting structures. As a result, the FE mesh encompasses only the system “VV + Cryostat + TS”. The 3D model requires much higher computational resources as compared to a shell model based on the equivalent approximation. The shell models have been developed for all principal conducting structures in the system “VV + Cryostat + TS” including regular ports and neutral beam ports. The structures are described in details in accordance with the latest design. The models have also been applied for simulations of EM transients in components of diagnostic systems and cryopumps and estimation of the 3D effects of the ITER structures on the plasma performance. The developed models have been elaborated and applied for the last 15 years to support the ITER design activities. The finalization of the ITER VV design enables this set of models to be considered ready to use in plasma-physics computations and the development of ITER simulators

Baking results of KSTAR vacuum vessel

International Nuclear Information System (INIS)

Kim, S. T.; Kim, Y. J.; Kim, K. M.; Im, D. S.; Joung, N. Y.; Yang, H. L.; Kim, Y. S.; Kwon, M.

2009-01-01

The Korea Superconducting Tokamak Advanced Research (KSTAR) is an advanced superconducting tokamak designed to establish a scientific and technological basis for an attractive fusion reactor. The fusion energy in the tokamak device is released through fusion reactions of light atoms such as deuterium or helium in hot plasma state, of which temperature reaches several hundreds of millions Celsius. The high temperature plasma is created in the vacuum vessel that provides ultra high vacuum status. Accordingly, it is most important for the vacuum condition to keep clean not only inner space but also surface of the vacuum vessel to make high quality plasma. There are two methods planned to clean the wall surface of the KSTAR vacuum vessel. One is surface baking and the other is glow discharge cleaning (GDC). To bake the vacuum vessel, De-Ionized (DI) water is heated to 130 .deg. C and circulated in the passage between double walls of the vacuum vessel (VV) in order to bake the surface. The GDC operation uses hydrogen and inert gas discharges. In this paper, general configuration and brief introduction of the baking result will be reported

Baking results of KSTAR vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Kim, S. T.; Kim, Y. J.; Kim, K. M.; Im, D. S.; Joung, N. Y.; Yang, H. L.; Kim, Y. S.; Kwon, M. [National Fusion Research Institute, Daejeon (Korea, Republic of)

2009-05-15

The Korea Superconducting Tokamak Advanced Research (KSTAR) is an advanced superconducting tokamak designed to establish a scientific and technological basis for an attractive fusion reactor. The fusion energy in the tokamak device is released through fusion reactions of light atoms such as deuterium or helium in hot plasma state, of which temperature reaches several hundreds of millions Celsius. The high temperature plasma is created in the vacuum vessel that provides ultra high vacuum status. Accordingly, it is most important for the vacuum condition to keep clean not only inner space but also surface of the vacuum vessel to make high quality plasma. There are two methods planned to clean the wall surface of the KSTAR vacuum vessel. One is surface baking and the other is glow discharge cleaning (GDC). To bake the vacuum vessel, De-Ionized (DI) water is heated to 130 .deg. C and circulated in the passage between double walls of the vacuum vessel (VV) in order to bake the surface. The GDC operation uses hydrogen and inert gas discharges. In this paper, general configuration and brief introduction of the baking result will be reported.

Vacuum Mechatronics And Insvection For Self-Contained Manufacturing

Science.gov (United States)

Belinski, Steve E.; Shirazi, Majid; Seidel, Thomas E.; Hackwood, Susan

1990-02-01

The vacuum environment is increasingly being used in manufacturing operations, especially in the semiconductor industry. Shrinking linewidths and feature sizes dictate that cleanliness standards become continually more strict. Studies at the Center for Robotic Systems in Microelectronics (CRSM) indicate that a controlled vacuum enclosure can provide a superior clean environment. In addition, since many microelectronic fabrication steps are already carried out under vacuum, self-contained multichamber processing systems are being developed at a rapid pace. CRSM support of these systems includes the development of a research system, the Self-contained Automated Robotic Factory (SCARF), a vacuum-compatible robot, and investigations of particulate characterization in vacuum and inspection for multichamber systems. Successful development of complex and expensive multichamber systems is, to a great extent, dependent upon the discipline called vacuum mechatronics, which includes the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. Here the constituents of the vacuum mechatronics discipline are defined and reviewed in the context of the importance to self-contained in-vacuum manufacturing.

Vacuum-plasma coverings on the aircraft

International Nuclear Information System (INIS)

Shvetsov, V.D.; Teksin, Eh.K.; Lysyak, A.A.

1998-01-01

In the article are considered the perspectives of vacuum-plasma coverings using for engine components protection. The influence of operating factors on the durability of components which has the vacuum-plasma coverings is show.Leads in using the concept of informational parameter of quality.The recommendation about organization of engine with abolished components maintenance by methods of flyable conditions or reliability level are given

The vacuum interlock system for the CELSIUS ring

International Nuclear Information System (INIS)

Gajewski, K.

1990-01-01

A vacuum interlock system has been designed and built for the CELSIUS storage ring. The ultrahigh-vacuum system of CELSIUS has a design pressure of 10 -11 mbar. This is achieved by using vacuum-fired stainless-steel chambers, baking the whole ring to 300degC and running some 50 sputter ion and titanium sublimation pumps. The turbopumps, combined with roughing pumps, are used during the pump-down and the bake-out. The pressure is monitored by Penning vacuum gauges. There is a number of programmable pressure thresholds set to trigger various events (like closing the sector valves, disabling the bake-out, etc.). The interlock system is based on the Mitsubishi programmable logic controller (PLC). An IBM PC is used as an operator's console. The operation and performance of the system is described. On the basis of present experience an upgrading of the system is suggested. (orig.)

Vacuum chamber-free centrifuge with magnetic bearings.

Science.gov (United States)

Park, Cheol Hoon; Kim, Soohyun; Kim, Kyung-Soo

2013-09-01

Centrifuges are devices that separate particles of different densities and sizes through the application of a centrifugal force. If a centrifuge could be operated under atmospheric conditions, all vacuum-related components such as the vacuum chamber, vacuum pump, diffusion pump, and sealing could be removed from a conventional centrifuge system. The design and manufacturing procedure for centrifuges could then be greatly simplified to facilitate the production of lightweight centrifuge systems of smaller volume. Furthermore, the maintenance costs incurred owing to wear and tear due to conventional ball bearings would be eliminated. In this study, we describe a novel vacuum chamber-free centrifuge supported by magnetic bearings. We demonstrate the feasibility of the vacuum chamber-free centrifuge by presenting experimental results that verify its high-speed support capability and motoring power capacity.

IWR-solution for the ITER vacuum vessel assembly

Energy Technology Data Exchange (ETDEWEB)

Wu, H., E-mail: huapeng@lut.fi [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland); Handroos, H. [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland); Pela, P. [Tekes (Finland); Wang, Y. [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland)

2011-10-15

The assembly of ITER vacuum vessel (VV) is still a very big challenge as the process can only be done from inside the VV. The welding of the VV assembly is carried out using the dedicated robotic systems. The main functions of the robots are: (i) measuring the actual space between every two sectors, (ii) positioning of the 150 kg splice plates between the sector shells, (iii) welding the splice plates to the sector shells, (iv) NDT of the welds, (v) repairing, including machining of the welds, (vi) He-leak tests of the welds, and (vii) the non-planned functions that may turn out. This paper presents a reasonable method to assemble the ITER VV. In this article, one parallel mobile robot, running on the track rail fixed on the wall inside the VV, is designed and tested. The assembling process, carried out by the mobile robot together with the welding robot, is presented.

DC photogun vacuum characterization through photocathode lifetime studies

International Nuclear Information System (INIS)

Marcy Stutzman; Joseph Grames; Matt Poelker; Kenneth Surles-Law; Philip Adderley

2007-01-01

Excellent vacuum is essential for long photocathode lifetimes in DC high voltage photoelectron guns. Vacuum Research at Thomas Jefferson National Accelerator Facility has focused on characterizing the existing vacuum systems at the CEBAF polarized photoinjector and on quantifying improvements for new systems. Vacuum chamber preprocessing, full activation of NEG pumps and NEG coating the chamber walls should improve the vacuum within the electron gun, however, pressure measurement is difficult at pressures approaching the extreme-high-vacuum (XHV) region and extractor gauge readings are not significantly different between the improved and original systems. The ultimate test of vacuum in a DC high voltage photogun is the photocathode lifetime, which is limited by the ionization and back-bombardment of residual gasses. Discussion will include our new load-locked gun design as well as lifetime measurements in both our operational and new photo-guns, and the correlations between measured vacuum and lifetimes will be investigated

CAS CERN Accelerator School vacuum technology. Proceedings

International Nuclear Information System (INIS)

Turner, S.

1999-01-01

These proceedings present the lectures given at the twelfth specialized course organized by the CERN Accelerator School (CAS), the topic this time being 'Vacuum Technology'. Despite the importance of vacuum technology in the design and operation of particle accelerators at CERN and at the many other accelerators already installed around the world, this was the first time that CAS has organized a course devoted entirely to this topic. Perhaps this reflects the facts that vacuum has become one of the more critical aspects of future accelerators, and that many of the pioneers in the accelerator field are being replaced by new, younger personnel. The lectures start with the basic concepts of the physics and technology of vacuum followed by detailed descriptions of the many different types of gas-pumping devices and methods to measure the pressures achieved. The outgassing characteristics of the different materials used in the construction of vacuum systems and the optimisation of cleaning methods to reduce this outgassing are then explained together with the effects of the residual gases on the particle beams. Then follow chapters on leak detection, materials and vacuum system engineering. Finally, seminars are presented on designing vacuum systems, the history of vacuum devices, the LHC (large hadron collider) vacuum system, vacuum systems for electron storage rings, and quality assurance for vacuum. (orig.)

Characterization of magnetic Ni clusters on graphene scaffold after high vacuum annealing

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhenjun, E-mail: zzhang1@albany.edu; Matsubayashi, Akitomo, E-mail: norwegianwood.1984@gmail.com; Grisafe, Benjamin, E-mail: bgrisafe@albany.edu; Lee, Ji Ung, E-mail: jlee1@albany.edu; Lloyd, James R., E-mail: JLloyd@sunycnse.com

2016-02-15

Magnetic Ni nanoclusters were synthesized by electron beam deposition utilizing CVD graphene as a scaffold. The subsequent clusters were subjected to high vacuum (5−8 x10{sup −7} torr) annealing between 300 and 600 °C. The chemical stability, optical and morphological changes were characterized by X-ray photoemission microscopy, Raman spectroscopy, atomic force microscopy and magnetic measurement. Under ambient exposure, nickel nanoparticles were observed to be oxidized quickly, forming antiferromagnetic nickel oxide. Here, we report that the majority of the oxidized nickel is in non-stoichiometric form and can be reduced under high vacuum at temperature as low as 300 °C. Importantly, the resulting annealed clusters were relatively stable and no further oxidation was detectable after three weeks of air exposure at room temperature. - Highlights: • Random oriented nickel clusters were assembled on monolayer graphene scaffold. • Nickel oxide shell was effectively reduced at moderate temperature. • Coercivity of nickel clusters are greatly improved after high vacuum annealing.

Big Bang Titanic: New Dark Energy (Vacuum Gravity) Cosmic Model Emerges Upon Falsification of The Big Bang By Disproof of Its Central Assumptions

Science.gov (United States)

Gentry, Robert

2011-04-01

Physicists who identify the big bang with the early universe should have first noted from Hawking's A Brief History of Time, p. 42, that he ties Hubble's law to Doppler shifts from galaxy recession from a nearby center, not to bb's unvalidated and thus problematical expansion redshifts. Our PRL submission LJ12135 describes such a model, but in it Hubble's law is due to Doppler and vacuum gravity effects, the 2.73K CBR is vacuum gravity shifted blackbody cavity radiation from an outer galactic shell, and its (1 + z)-1 dilation and (M,z) relations closely fit high-z SNe Ia data; all this strongly implies our model's vacuum energy is the elusive dark energy. We also find GPS operation's GR effects falsify big bang's in-flight expansion redshift paradigm, and hence the big bang, by showing λ changes occur only at emission. Surprisingly we also discover big bang's CBR prediction is T 0, while galactic photons shrink dλ/dt < 0. Contrary to a PRL editor's claim, the above results show LJ12135 fits PRL guidelines for papers that replace established theories. For details see alphacosmos.net.

Baryogenesis in false vacuum

Energy Technology Data Exchange (ETDEWEB)

Hamada, Yuta [KEK Theory Center, IPNS, KEK, Tsukuba, Ibaraki (Japan); Yamada, Masatoshi [Kanazawa University, Institute for Theoretical Physics, Kanazawa (Japan)

2017-09-15

The null result in the LHC may indicate that the standard model is not drastically modified up to very high scales, such as the GUT/string scale. Having this in the mind, we suggest a novel leptogenesis scenario realized in the false vacuum of the Higgs field. If the Higgs field develops a large vacuum expectation value in the early universe, a lepton number violating process is enhanced, which we use for baryogenesis. To demonstrate the scenario, several models are discussed. For example, we show that the observed baryon asymmetry is successfully generated in the standard model with higher-dimensional operators. (orig.)

Corrections to the free-nucleon values of the single-particle matrix elements of the M1 and Gamow-Teller operators, from a comparison of shell-model predictions with sd-shell data

International Nuclear Information System (INIS)

Brown, B.A.; Wildenthal, B.H.

1983-01-01

The magnetic dipole moments of states in mirror pairs of the sd-shell nuclei and the strengths of the Gamow-Teller beta decays which connect them are compared with predictions based on mixed-configuration shell-model wave functions. From this analysis we extract the average effective values of the single-particle matrix elements of the l, s, and [Y/sup( 2 )xs]/sup( 1 ) components of the M1 and Gamow-Teller operators acting on nucleons in the 0d/sub 5/2/, 1s/sub 1/2/, and 0d/sub 3/2/ orbits. These results are compared with the recent calculations by Towner and Khanna of the corrections to the free-nucleon values of these matrix elements which arise from the effects of isobar currents, mesonic-exchange currents, and mixing with configurations outside the sd shell

Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

International Nuclear Information System (INIS)

Amendt, Peter; Cerjan, C.; Hamza, A.; Hinkel, D. E.; Milovich, J. L.; Robey, H. F.

2007-01-01

The goal of demonstrating ignition on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2003)] has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include noncryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (≅4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT (≅790 atm) in the inner shell, strict concentricity requirements on the two shells ( 2 nanoporous aerogels with suspended Cu particles. A prototype demonstration of an ignition DS is planned for 2008, incorporating the needed novel nanomaterials science developments and the required fabrication tolerances for a realistic ignition attempt after 2010

Automation of Aditya vacuum control system based on CODAC Core System

Energy Technology Data Exchange (ETDEWEB)

Raulji, Vismaysinh D., E-mail: vismay@ipr.res.in; Pujara, Harshad; Arambhadiya, Bharat; Jadeja, Kumarpalsinh; Bhatt, Shailesh; Rajpal, Rachana

2016-11-15

Highlights: • Monitor and control of vacuum control system based on CODAC Core System. • Communication between SIEMENS PLC and open source software EPICS. • With CODAC Core easy to configure and programming of slow controller. - Abstract: The main objective of vacuum control system is to provide ultrahigh vacuum for Aditya Tokamak operations. Aditya Vacuum vessel is having four vacuum pumping lines. To demonstrate implementation of automation; a study case is under taken by automating single Pumping Line of the Aditya vacuum system using CODAC Core System (CCS). Currently, vacuum system is operated manually. The CCS based control system allows remote control, monitoring, alarm handling of vacuum parameters. The CODAC Core System is the Linux based software package that is distributed by ITER Organization for the development of Plant System I&C software. CODAC Core System includes EPICS, CSS (Control System Studio) etc. CSS is used for HMI (Human Machine Interface), alarms and archives. SDD (Self Description Data) tool is used to configure plant system I&C. SDD Editor is an Eclipse based application to define the plant system, interface, I&C component, interfaced signals, configure variable. SCADA (Supervisory Control and Data Acquisition) system is developed in CSS. Data is transferred between PLC and CSS through EPICS. The complete system is tested with Aditya Vacuum Control System with process interlocks. Operator interface is also developed using Lab VIEW as a choice of the user. This paper will describe the salient features of the developed control system in detail.

The SPEAR3 Vacuum System - An Analysis of the First Two Years of Operation (2004 and 2005)

International Nuclear Information System (INIS)

Armenta, R.

2005-01-01

SPEAR 3, a synchrotron radiation source at the Stanford Linear Accelerator Center, has been in operation for the past two years. SPEAR 3 was designed to achieve high beam lifetimes while operating at a higher current level than previously achieved with SPEAR 2. Maintaining high electron beam lifetimes within the ring allows users to perform their experiments with a consistent supply of high current synchrotron radiation. The purpose of this analysis is to evaluate the SPEAR 3 vacuum system's performance during the 2004 and 2005 runs while considering methods to optimize and improve vacuum system conditioning, especially within the pumping system, so that a recommended plan of action can be created for the FY 2006 run. Monitoring the dynamics of the electron beam within the ring can be a difficult task. Pressure data obtained from the gages attached to pumps, temperature data obtained from thermocouples located at various locations around the ring, and beam lifetime projections help to provide some indication of the health of the electron beam, but the true conditions within the beam chamber can only be extrapolated. Data collected from sensors (gauges, thermocouples, etc.) located around the ring can be viewed and extracted from a program created at the Stanford Synchrotron Radiation Laboratory (SSRL) called Historyplot. Manipulation and analysis of data was performed with the commercially available programs Matlab and Excel. The data showed that the beam lifetimes in 2005 were much greater than they were in 2004, but it did not provide a clear indication as to why this occurred. One variable of major importance between the 2004 and 2005 runs is the Titanium Sublimation Pump (TSP) flash frequency (flashing is the process in which Titanium from filaments within the pump is sublimated onto the wall surfaces of the pump, where it removes gas molecules from the system by chemisorption). The data indicated that pressures in 2005 could have been lower, based on a

Vacuum ARC ion sources - activities ampersand developments at LBL

International Nuclear Information System (INIS)

Brown, I.

1996-01-01

The author describes work at LBL on the development and application of vacuum arc ion sources. Work has been done on vacuum spark sources - to produce very high charge states, studies of high charge states in magnetic field, hybrid ion source operation on metal/gas plasma, multipole operation, work on MEVVA V for implantation applications, development of broad beam sources, and removal of particles from the output of the source

LHC vacuum system

CERN Document Server

Gröbner, Oswald

1999-01-01

The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the inner 'cold bore' walls of the magnets. These magnets operate at 1.9 K, and thus serve as very good cryo-pumps. In order to reduce the cryogenic power consumption, both the heat load from synchrotron radiation emitted by the proton beams and the resistive power dissipation by the beam image currents have to be absorbed on a 'beam screen', which operates between 5 and 20 K and is inserted inside the vacuum chamber. The design of this beam screen represents a technological challenge in view of the numerous and often conflicting requirements and the very tight mechanical tolerances imposed. The synchrotron radiation produces strong outgassing from the...

The Remotely Operated Nondestructive Examination System for Examining the Knuckle Region of Hanford's Double Shell Waste Tanks

International Nuclear Information System (INIS)

Crawford, Susan L.; Pardini, Allan F.; Donald Thompson and Dale Chimenti

2005-01-01

The Pacific Northwest National Laboratory has developed a technology to address the examination requirements associated with the knuckle region of Hanford's double shell waste tanks. This examination poses a significant technical challenge because the area that requires examination is in a confined space, high radiation region and is not accessible using conventional measurement techniques. This paper describes the development, deployment, and modification of the remotely operated nondestructive examination (RONDE) system that utilizes a technique known as Synthetic Aperture Focusing (SAFT). The system detects stress corrosion cracking in the high stress region of the knuckle and characterizes the crack with tandem SAFT. PNNL has qualified the system to perform inspections on the entire knuckle region of Hanford's double shell waste tanks

Improvement of the operational performance of SRF cavities via in situ helium processing and waveguide vacuum processing

International Nuclear Information System (INIS)

Reece, C.E.; Drury, M.; Rao, M.G.; Nguyen-Tuong, V.

1997-01-01

The useful performance range of the superconducting rf (SRF) cavities in the CEBAF accelerator at Jefferson Lab is frequently limited by electron field emission and derived phenomena. Improvements are required to support future operation of the accelerator at higher than 5 GeV. Twelve operational cryomodules have been successfully processed to higher useful operating gradients via rf-helium processing. Progress against field emission was evidenced by improved high-field Q, reduced x-ray production and greatly reduced incidence of arcing at the cold ceramic window. There was no difficulty reestablishing beamline vacuum following the processing. Cavities previously limited to 4-6 MV/m are now operating stably at 6-9 MV/m. By applying a pulsed-rf processing technique, we have also improved the pressure stability of the thermal transition region of the input waveguide for several cavities

Development of vacuum brazing furnace

International Nuclear Information System (INIS)

Singh, Rajvir; Yedle, Kamlesh; Jain, A.K.

2005-01-01

In joining of components where welding process is not possible brazing processes are employed. Value added components, high quality RF systems, UHV components of high energy accelerators, carbide tools etc. are produced using different types of brazing methods. Furnace brazing under vacuum atmosphere is the most popular and well accepted method for production of the above mentioned components and systems. For carrying out vacuum brazing successfully it is essential to have a vacuum brazing furnace with latest features of modern vacuum brazing technology. A vacuum brazing furnace has been developed and installed for carrying out brazing of components of copper, stainless steel and components made of dissimilar metals/materials. The above furnace has been designed to accommodate jobs of 700mm diameter x 2000mm long sizes with job weight of 500kgs up to a maximum temperature of 1250 degC at a vacuum of 5 x 10 -5 Torr. Oil diffusion pumping system with a combination of rotary and mechanical booster pump have been employed for obtaining vacuum. Molybdenum heating elements, radiation shield of molybdenum and Stainless Steel Grade 304 have been used. The above furnace is computer controlled with manual over ride facility. PLC and Pentium PC are integrated together to maneuver steps of operation and safety interlocks of the system. Closed loop water supply provides cooling to the system. The installation of the above system is in final stage of completion and it will be ready for use in next few months time. This paper presents insights of design and fabrication of a modern vacuum brazing furnace and its sub-system. (author)

Human machine interface based on labview for vacuum system operation of cyclotron proton DECY-13 MeV

International Nuclear Information System (INIS)

Fajar Sidik Permana; Saminto; Kurnia Wibowo; Vika Arwida Fanita Sari

2016-01-01

Center of Accelerator Science and Technology (CAST), BATAN is designing DECY-13 MeV Proton Cyclotron. So far, this operation system has been conducted conventionally. In this research, an Human Machine Interface system has been successfully built for simplifying operation and monitoring pressure inside vacuum chamber of cyclotron DECY-13 MeV. HMI system is built with LabVIEW software and integrated with Programmable Logic Controller FX-2424 series and NI cRIO (NI-9025 and NI-9870) module. HMI system consist of turning on/of pumps (rotary and diffusion), opening/ closing valve automatically, and retrieving of data from sensor in real time. (author)

Recent advances in vacuum arc ion sources

International Nuclear Information System (INIS)

Brown, I.G.; Anders, A.; Anders, S.; Dickinson, M.R.; MacGill, R.A.; Oks, E.M.

1995-07-01

Intense beams of metal ions can be formed from a vacuum arc ion source. Broadbeam extraction is convenient, and the time-averaged ion beam current delivered downstream can readily be in the tens of milliamperes range. The vacuum arc ion source has for these reasons found good application for metallurgical surface modification--it provides relatively simple and inexpensive access to high dose metal ion implantation. Several important source developments have been demonstrated recently, including very broad beam operation, macroparticle removal, charge state enhancement, and formation of gaseous beams. The authors have made a very broad beam source embodiment with beam formation electrodes 50 cm in diameter, producing a beam of width ∼35 cm for a nominal beam area of ∼1,000 cm 2 , and a pulsed Ti beam current of about 7 A was formed at a mean ion energy of ∼100 keV. Separately, they've developed high efficiency macroparticle-removing magnetic filters and incorporated such a filter into a vacuum arc ion source so as to form macroparticle-free ion beams. Jointly with researchers at the High Current Electronics Institute at Tomsk, Russia, and the Gesellschaft fuer Schwerionenforschung at Darmstadt, Germany, they've developed a compact technique for increasing the charge states of ions produced in the vacuum arc plasma and thus providing a simple means of increasing the ion energy at fixed extractor voltage. Finally, operation with mixed metal and gaseous ion species has been demonstrated. Here, they briefly review the operation of vacuum marc ion sources and the typical beam and implantation parameters that can be obtained, and describe these source advances and their bearing on metal ion implantation applications

Vacuum Arc Ion Sources

CERN Document Server

Brown, I.

2013-12-16

The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the source has grown, so also have the operational characteristics been improved in a variety of different ways. Here we review the principles, design, and performance of vacuum arc ion sources.

Accounting of possibilities of blade oscillation emergence at the calculation of operating wheel of turbomolecular vacuum pump

International Nuclear Information System (INIS)

Pereslavlev, A.V.

1988-01-01

Possibilities of blade oscillation emergence in the operating wheel of turbomolecular vacuum pump (TVP) are considered. Permissible value of safety factor for tensile strength in the operating wheel blade root section, at which the necessary fatigue limit of a material is provided for (k=2 for aluminium alloys and k=1.5 for VT-8 titanium alloy) is determined. Methods of calculating the main dimensions of blade operating wheel on the basis of the specified maximum pumping speed, taking account of possibilities of blade oscillation emergence are presented. Results of calculating the 4S max/πD 2 2 complex, characterizing maximum speed of operating wheel pumping, depending on permissible tensipn in the blade root section (σ), are given. It is shown that (σ increase above (2.5 2.7)x10 8 Pa for aluminium alloys and above ∼ 4x10 8 Pa for VT titanium alloy don't cause increase of operating wheel maximum pumping speed. 8 refs.; 6 figs

Design of the vacuum control system for DIII-D

International Nuclear Information System (INIS)

Campbell, G.L.; Callis, R.W.; Haskovec, J.S.; Heckman, E.J.; Moore, C.D.; Scoville, J.T.

1986-01-01

The vacuum control and instrumentation for the DIII-D upgrade was designed using a new large programmable controller with color graphic operator interfaces and intelligent distributed devices. Remote, optically isolated input and output is used as well as optical isolation for the operator and programming consoles. Gate valves between experimental equipment and the vacuum vessel are interlocked for machine safety by an intelligent interface based upon a commercially available microcontroller card. Complete automatic operation with capability for remote operator intervention was one goal of this design effort. The design of the system with emphasis on the graphics, optical isolation and microcontroller implementation will be discussed

Bio oil from pyrolysis of cashew nut shell-characterisation and related properties

International Nuclear Information System (INIS)

Das, Piyali; Sreelatha, T.; Ganesh, Anuradda

2004-01-01

Biomass in the form of cashew nut shell represents a renewable and abundant source of energy in India. Cashew nut shell (CNS) was pyrolysed in a fixed bed pyrolysis reactor under vacuum. The CNS on heating upto 175 deg. C produced dark brown oil (oil CO1), which was extracted, and the CNS, after the removal of oil CO1, was pyrolysed under vacuum. The pyrolysis vapours were condensed to get a combustible oil fraction (oil CO2) as well as a noncombustible aqueous fraction. The detailed chemical compositional analysis of both the oils as well as aqueous fractions were carried out by various techniques like liquid column chromatography 1 HNMR, 13 CNMR, FTIR, GC-MS. The CNS oils (CO1 and CO2) were found to be a renewable natural resource of unsaturated phenols with long linear chains and marked absence of anacardic acid. Unlike other bio oils, the CNS oils have been found to be fairly stable. The oils were completely miscible in diesel and were found to have low corrosivity towards Copper and Stainless steel, and thus promise to be a potential fuel

Design and construction of Alborz tokamak vacuum vessel system

International Nuclear Information System (INIS)

Mardani, M.; Amrollahi, R.; Koohestani, S.

2012-01-01

Highlights: ► The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. ► As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. ► A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma–surface interaction and localizes the particle recycling. ► Structural analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. - Abstract: The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. At the heart of the tokamak is the vacuum vessel and limiter which collectively are referred to as the vacuum vessel system. As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. The VV systems need upper and lower vertical ports, horizontal ports and oblique ports for diagnostics, vacuum pumping, gas puffing, and maintenance accesses. A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma–surface interaction and localizes the particle recycling. Basic structure analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. Stresses at general part of the VV body are lower than the structure material allowable stress (117 MPa) and this analysis show that the maximum stresses occur near the gravity support, and is about 98 MPa.

Commissioning of the vacuum straw tracker for the COSY-TOF spectrometer

Energy Technology Data Exchange (ETDEWEB)

Roeder, Matthias; Ritman, James; Voigtlaender, Pierre; Wintz, Peter [Institut fuer Kernphysik I, Forschungszentrum Juelich GmbH (Germany)

2009-07-01

The Straw-Tracker at COSY-TOF is a system of 3120 Straws arranged in 30 layers. These are operated at 1.2 bar drift-gas pressure in the TOF vacuum so that they are self-supporting, despite their mylar wrapping being only 30 {mu}m thick. As a result the total radiation length amounts to only 1 %. The operation with 1500 V anode voltage in medium vacuum at {approx}5.10{sup -3} mbar imposes stringent demands on detector design and handling. In this talk the system is introduced and it is reported on the commissioning during the year 2008. The emphasis is placed on vacuum operation and results on the efficiency and resolution under experiment conditions.

Analytical and numerical tools for vacuum systems

CERN Document Server

Kersevan, R

2007-01-01

Modern particle accelerators have reached a level of sophistication which require a thorough analysis of all their sub-systems. Among the latter, the vacuum system is often a major contributor to the operating performance of a particle accelerator. The vacuum engineer has nowadays a large choice of computational schemes and tools for the correct analysis, design, and engineering of the vacuum system. This paper is a review of the different type of algorithms and methodologies which have been developed and employed in the field since the birth of vacuum technology. The different level of detail between simple back-of-the-envelope calculations and more complex numerical analysis is discussed by means of comparisons. The domain of applicability of each method is discussed, together with its pros and cons.

Carbon nanotubes based vacuum gauge

Science.gov (United States)

Rudyk, N. N.; Il'in, O. I.; Il'ina, M. V.; Fedotov, A. A.; Klimin, V. S.; Ageev, O. A.

2017-11-01

We have created an ionization type Vacuum gauge with sensor element based on an array of vertically aligned carbon nanotubes. Obtained asymmetrical current-voltage characteristics at different voltage polarity on the electrode with the CNTs. It was found that when applying a negative potential on an electrode with the CNTs, the current in the gap is higher than at a positive potential. In the pressure range of 1 ÷ 103 Torr vacuum gauge sensitivity was 6 mV/Torr (at a current of 4.5·10-5 A) and in the range of 10-5 ÷ 1 Torr was 10 mV/Torr (at a current of 1.3·10-5 A). It is shown that the energy efficiency of vacuum gauge can be increased in the case where electrode with CNT operates as an emitter of electrons.

A continuous wave RF vacuum window

International Nuclear Information System (INIS)

Walton, R.

1999-09-01

An essential part of an ICRF system to be used in fusion reactor is the RF window. This is fitted in a coaxial transmission line. It forms a vacuum and tritium boundary between the antenna, situated inside the machine, and the transmission line, which feeds it. A double window is required with a vacuum inter-space. The dielectric, which forms the vacuum boundary, must be brazed into its housing. The window must be of a robust construction, and capable of withstanding both axial and radial loads. The vacuum boundaries should be thick walled in order act as a suitable tritium barrier. A further requirement is that the window is capable of continuous operation. The design of such a window is presented below. A half scale prototype has been manufactured, which has successfully completed RF, vacuum, and mechanical testing at JET, but has no water cooling, which is a requirement for continuous operation. The design presented here is for a window to match the existing 30 Ω main transmission lines at JET. It employs two opposed ceramic dielectric cones with a much increased angle of incidence compared with existing JET windows. The housing is machined from titanium. Small corona rings are used, and the tracking distance along the ceramic surface is large. The geometry minimizes the peak electric field strength. The design uses substantial pre-stressing during manufacture, to produce a compressive stress field throughout the dielectric material. Significant tensile stresses in the ceramic, and therefore the possibility of fracture due to applied thermal and mechanical loading, are eliminated in this way. A full-scale actively cooled RF window using this basic design should be capable of continuous use at 50 kV in the 20 - 90 MHz range. A half scale, inertially cooled prototype window has been designed, built and tested successfully at JET to 48 kV for up to 20 seconds. The prototype uses alumina for the dielectric, whereas beryllia is more appropriate for continuous

Vacuum distillation/vapor filtration water recovery

Science.gov (United States)

Honegger, R. J.; Neveril, R. B.; Remus, G. A.

1974-01-01

The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine.

Shell report 2001; Les personnes, la planete, les profits. Shell rapport 2001

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

In 2001, Shell saw mixed results across the social, environmental and economic spectrum. In order to contribute to the sustainable development, the Group is on track towards meeting its target to reduce greenhouse gas emissions to 10 % below 1990 levels by the end of 2002, although there was a significant increase in spill volumes and greenhouse gas emissions rose. Shell has articulated the business case and defined seven principles of sustainable development for use across the Group in business plans and daily operations: generating robust profitability; delivering value to customers; protecting the environment; managing resources; respecting and safeguarding people; benefiting communities; and working with stakeholders. Key points from the Shell Report include: in the framework of Managing, an independent review of the Shell Nigeria Community Development programme and testing of a human rights assessment tool in Shell South Africa and the implementing of a new Diversity and Inclusiveness Standard; in the framework of the economy the cost improvements of 5,1 billion dollars, ahead of target, the second highest earnings ever in difficult market conditions and the election of Shell top brand for fifth year running by motorists; in the framework of the Social, the safety performance, the avoidance of 100 contracts for incompatibility with Shell Business Principles; in the framework of the Environment, the publication of the Fresh water usage report for the first time, the Greenhouse gas emissions, the increase of spills as a result of a small number of incidents including a pipeline rupture in Nigeria and a well blow out in Oman. The economic, environmental and social data of the Shell Report are externally verified. (A.L.B.)

Shell model Monte Carlo methods

International Nuclear Information System (INIS)

Koonin, S.E.

1996-01-01

We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, thermal behavior of γ-soft nuclei, and calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. 87 refs

Baking of SST-1 vacuum vessel modules and sectors

International Nuclear Information System (INIS)

Pathan, Firozkhan S; Khan, Ziauddin; Yuvakiran, Paravastu; George, Siju; Ramesh, Gattu; Manthena, Himabindu; Shah, Virendrakumar; Raval, Dilip C; Thankey, Prashant L; Dhanani, Kalpesh R; Pradhan, Subrata

2012-01-01

SST-1 Tokamak is a steady state super-conducting tokamak for plasma discharge of 1000 sec duration. The plasma discharge of such long time duration can be obtained by reducing the impurities level, which will be possible only when SST-1 vacuum chamber is pumped to ultra high vacuum. In order to achieve UHV inside the chamber, the baking of complete vacuum chamber has to be carried out during pumping. For this purpose the C-channels are welded inside the vacuum vessel. During baking of vacuum vessel, these welded channels should be helium leak tight. Further, these U-channels will be in accessible under operational condition of SST-1. So, it will not possible to repair if any leak is developed during experiment. To avoid such circumstances, a dedicated high vacuum chamber is used for baking of the individual vacuum modules and sectors before assembly so that any fault during welding of the channels will be obtained and repaired. This paper represents the baking of vacuum vessel modules and sectors and their temperature distribution along the entire surface before assembly.

The Control System of CERN Accelerators Vacuum (Current Status and Recent Improvements)

CERN Document Server

Gomes, P; Blanchard, S; Boccioli, M; Girardot, G; Vestergard, H; Kopylov, L; Mikheev, M

2011-01-01

The vacuum control system of most of the CERN accelerators is based on Siemens PLCs and on PVSS SCADA. After the transition from the LHC commissioning phase to its regular operation, there has been a number of additions and improvements to the vacuum control system. They were driven by new technical requirements and by feedback from the accelerator operators and vacuum specialists. New control functions have been implemented in the PLCs; new tools have been developed for the SCADA, while its ergonomics and navigation have been enhanced.

Decision 99-8 : Shell Canada Limited application to construct and operate an oil sands bitumen upgrader in the Fort Saskatchewan area : Shell Canada Products Limited application to amend refinery approval in the Fort Saskatchewan area

International Nuclear Information System (INIS)

1999-01-01

The Alberta Energy and Utilities Board considered an application by Shell Canada Limited to construct and operate an oil sands bitumen upgrader on Shell's property adjoining the existing Scotford refinery in the County of Strathcona. The upgrader would process bitumen from Shell's proposed Muskeg River Mine, located 70 km north of Fort McMurray, and other feedstocks available in the area. The Board also considered an application for an amendment to the existing Scotford refinery approval, Industrial Development Permit 89-10, for the processing of 3.75 million cubic metres per year of sour conversion feedstock. Under a coordinated application process, Shell filed a joint Shell Scotford Upgrader application/Environmental Impact Assessment. Issues considered with respect to these applications were: technology selection, air/health, sulphur recovery, noise/traffic, and land use conflict. Shell stated that its Scotford refinery is the most energy efficient refinery in the Americas and that is has the highest liquid yield per unit volume of crude oil feedstock of any refinery in the world. The refinery's hydrocracking capacity would make it possible to use hydro-conversion technology for its upgrader which is environmentally advantageous. After examining all of the evidence pertaining to the applications, the Board found the projects to be in the public interest and is prepared to approve the Scotford Upgrader and Scotford Refinery modifications assuming that certain prescribed conditions are met

Fast ignition upon the implosion of a thin shell onto a precompressed deuterium-tritium ball

Science.gov (United States)

Gus'kov, S. Yu.; Zmitrenko, N. V.

2012-11-01

Fast ignition of a precompressed inertial confinement fusion (ICF) target by a hydrodynamic material flux is investigated. A model system of hydrodynamic objects consisting of a central deuterium-tritium (DT) ball and a concentric two-layer shell separated by a vacuum gap is analyzed. The outer layer of the shell is an ablator, while the inner layer consists of DT ice. The igniting hydrodynamic flux forms as a result of laser-driven acceleration and compression of the shell toward the system center. A series of one-dimensional numerical simulations of the shell implosion, the collision of the shell with the DT ball, and the generation and propagation of thermonuclear burn waves in both parts of the system are performed. Analytic models are developed that describe the implosion of a thin shell onto a central homogeneous ball of arbitrary radius and density and the initiation and propagation of a thermonuclear burn wave induced by such an implosion. Application of the solution of a model problem to analyzing the implosion of a segment of a spherical shell in a conical channel indicates the possibility of fast ignition of a spherical ICF target from a conical target driven by a laser pulse with an energy of 500-700 kJ.

Development of a master model concept for DEMO vacuum vessel

International Nuclear Information System (INIS)

Mozzillo, Rocco; Marzullo, Domenico; Tarallo, Andrea; Bachmann, Christian; Di Gironimo, Giuseppe

2016-01-01

Highlights: • The present work concerns the development of a first master concept model for DEMO vacuum vessel. • A parametric-associative CAD master model concept of a DEMO VV sector has been developed in accordance with DEMO design guidelines. • A proper CAD design methodology has been implemented in view of the later FEM analyses based on “shell elements”. - Abstract: This paper describes the development of a master model concept of the DEMO vacuum vessel (VV) conducted within the framework of the EUROfusion Consortium. Starting from the VV space envelope defined in the DEMO baseline design 2014, the layout of the VV structure was preliminarily defined according to the design criteria provided in RCC-MRx. A surface modelling technique was adopted and efficiently linked to the finite element (FE) code to simplify future FE analyses. In view of possible changes to shape and structure during the conceptual design activities, a parametric design approach allows incorporating modifications to the model efficiently.

Development of a master model concept for DEMO vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Mozzillo, Rocco; Marzullo, Domenico; Tarallo, Andrea [CREATE, University of Naples Federico II, DII, P.le Tecchio 80, 80125, Naples (Italy); Bachmann, Christian [EUROfusion PMU, Boltzmannstraße 2, 85748 Garching (Germany); Di Gironimo, Giuseppe, E-mail: peppe.digironimo@gmail.com [CREATE, University of Naples Federico II, DII, P.le Tecchio 80, 80125, Naples (Italy)

2016-11-15

Highlights: • The present work concerns the development of a first master concept model for DEMO vacuum vessel. • A parametric-associative CAD master model concept of a DEMO VV sector has been developed in accordance with DEMO design guidelines. • A proper CAD design methodology has been implemented in view of the later FEM analyses based on “shell elements”. - Abstract: This paper describes the development of a master model concept of the DEMO vacuum vessel (VV) conducted within the framework of the EUROfusion Consortium. Starting from the VV space envelope defined in the DEMO baseline design 2014, the layout of the VV structure was preliminarily defined according to the design criteria provided in RCC-MRx. A surface modelling technique was adopted and efficiently linked to the finite element (FE) code to simplify future FE analyses. In view of possible changes to shape and structure during the conceptual design activities, a parametric design approach allows incorporating modifications to the model efficiently.

Hardware design of a microcomputer controlled diagnostic vacuum controller

International Nuclear Information System (INIS)

Marsala, R.J.

1983-01-01

The TFTR diagnostic vacuum controller (DVC) has been designed and built to control and monitor the pumps, valves and gauges which comprise a diagnostic vacuum system. The DVC is a microcomputer based self-contained controller with battery backup which may be controlled manually from front panel controls or remotely via CICADA. The DVC implements all pump and valve sequencing and provides protection against incorrect operation. There are presently two versions of the DVC operating on TFTR and a third version being used on the S-1 machine

Optimization of a near-field thermophotovoltaic system operating at low temperature and large vacuum gap

Science.gov (United States)

Lim, Mikyung; Song, Jaeman; Kim, Jihoon; Lee, Seung S.; Lee, Ikjin; Lee, Bong Jae

2018-05-01

The present work successfully achieves a strong enhancement in performance of a near-field thermophotovoltaic (TPV) system operating at low temperature and large-vacuum-gap width by introducing a hyperbolic-metamaterial (HMM) emitter, multilayered graphene, and an Au-backside reflector. Design variables for the HMM emitter and the multilayered-graphene-covered TPV cell are optimized for maximizing the power output of the near-field TPV system with the genetic algorithm. The near-field TPV system with the optimized configuration results in 24.2 times of enhancement in power output compared with that of the system with a bulk emitter and a bare TPV cell. Through the analysis of the radiative heat transfer together with surface-plasmon-polariton (SPP) dispersion curves, it is found that coupling of SPPs generated from both the HMM emitter and the multilayered-graphene-covered TPV cell plays a key role in a substantial increase in the heat transfer even at a 200-nm vacuum gap. Further, the backside reflector at the bottom of the TPV cell significantly increases not only the conversion efficiency, but also the power output by generating additional polariton modes which can be readily coupled with the existing SPPs of the HMM emitter and the multilayered-graphene-covered TPV cell.

The control system of CERN accelerators vacuum (current status and recent improvements)

International Nuclear Information System (INIS)

Gomes, P.; Antoniotti, F.; Blanchard, S.; Boccioli, M.; Girardot, G.; Vestergard, H.; Kopylov, L.; Mikheev, M.

2012-01-01

The vacuum control system of most of the CERN accelerators is based on Siemens PLCs and on PVSS SCADA. After the transition from the LHC commissioning phase to its regular operation, there has been a number of additions and improvements to the vacuum control system. They were driven by new technical requirements and by feedback from the accelerator operators and vacuum specialists. New control functions have been implemented in the PLCs; new tools have been developed for the SCADA, while its ergonomic and navigation have been enhanced. (authors)

Method of fabricating nested shells and resulting product

Science.gov (United States)

Henderson, Timothy M.; Kool, Lawrence B.

1982-01-01

A multiple shell structure and a method of manufacturing such structure wherein a hollow glass microsphere is surface treated in an organosilane solution so as to render the shell outer surface hydrophobic. The surface treated glass shell is then suspended in the oil phase of an oil-aqueous phase dispersion. The oil phase includes an organic film-forming monomer, a polymerization initiator and a blowing agent. A polymeric film forms at each phase boundary of the dispersion and is then expanded in a blowing operation so as to form an outer homogeneously integral monocellular substantially spherical thermoplastic shell encapsulating an inner glass shell of lesser diameter.

Results from HBTX1C with close and distant resistive shells

International Nuclear Information System (INIS)

Alper, B.; Bevir, M.K.; Bodin, H.A.

1989-01-01

HBTX1C has operated with resistive shells to study, in particular, reversed field pinch (RFP) confinement where pulse lengths (τ p ) exceed the time constant for vertical field penetration of the wall (τ w ). Initial operation with τ w =0.5ms for a shell located at 1.15 times the minor radius, lead to the growth of low frequency (thin shell) modes which grew to termination in less than 5 ms. Mode numbers and growth rates were in agreement with linear MHD theory. The installation of a secondary shell distant from the plasma at 1.6 times the minor radius has significantly altered plasma properties and improved confinement. Thin shell operation permits dynamic control of plasma equilibrium. Using high current switching circuitry, feedback control of the horizontal position of the plasma has been successfully implemented. This has been followed by control of one phase of the external kink mode, (m,n)=(1,2), as a first step towards suppression of the growth of thin shell modes. Operation in the ultra-low-q (ULQ) regime of unreversed discharges with 0< q≤1 has been studied for currents ranging from 80 to 260 kA. (author) 6 refs., 3 figs

Resistive wall instabilities and tearing mode dynamics in the EXTRAP T2R thin shell reversed-field pinch

Science.gov (United States)

Malmberg, J.-A.; Brunsell, P. R.

2002-01-01

Observations of resistive wall instabilities and tearing mode dynamics in the EXTRAP T2R thin shell (τw=6 ms) reversed field pinch are described. A nonresonant mode (m=1,n=-10) with the same handedness as the internal field grows nearly exponentially with an average growth time of about 2.6 ms (less than 1/2 of the shell time) consistent with linear stability theory. The externally nonresonant unstable modes (m=1,n>0), predicted by linear stability theory, are observed to have only low amplitudes (in the normal low-Θ operation mode of the device). The radial field of the dominant internally resonant tearing modes (m=1,n=-15 to n=-12) remain low due to spontaneous fast mode rotation, corresponding to angular phase velocities up to 280 krad/s. Phase aligned mode structures are observed to rotate toroidally with an average angular velocity of 40 krad/s, in the opposite direction of the plasma current. Toward the end of the discharge, the radial field of the internally resonant modes grows as the modes slow down and become wall-locked, in agreement with nonlinear computations. Fast rotation of the internally resonant modes has been observed only recently and is attributed to a change of the front-end system (vacuum vessel, shell, and TF coil) of the device.

Leybold vacuum handbook

CERN Document Server

Diels, K; Diels, Kurt

1966-01-01

Leybold Vacuum Handbook presents a collection of data sets that are essential for numerical calculation of vacuum plants and vacuum processes. The title first covers vacuum physics, which includes gas kinetics, flow phenomena, vacuum gauges, and vapor removal. Next, the selection presents data on vacuum, high vacuum process technology, and gas desorption and gettering. The text also deals with materials, vapor pressure, boiling and melting points, and gas permeability. The book will be of great interest to engineers and technicians that deals with vacuum related technologies.

Indian Vacuum Society: The Indian Vacuum Society

Science.gov (United States)

Saha, T. K.

2008-03-01

The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of

Dutch supplier rewarded for manufacture of the two vacuum vessels for the ATLAS end-cap toroids

CERN Multimedia

Maximilien Brice

2003-01-01

The ATLAS collaboration has presented an award for outstanding supplier performance to Dutch firm Schelde Exotech. Based on a design by Rutherford Appleton Laboratory, UK, Schelde Exotech manufactured under a NIKHEF contract the two 500 m3 large vacuum vessels for the cryostats of the ATLAS end-cap toroids. These 11-metre diameter castellated aluminium vessels with stainless-steel bore tube are essentially made up of 40-mm-thick plates for the shells, 75-mm-thick plates for the endplates, and 150-mm-thick bars for the flanges. Because of transport constraints, the vessels were made in halves, temporarily sealed and vacuum tested at the works, then transported to CERN for final assembly and acceptance tests. Both vessels were vacuum-tight and the meticulous and clean way of working ensured that a high vacuum was obtained within a few days of pumping. The delivery to CERN was completed in July 2002. Representatives of Schelde Exotech are seen here receiving their award in the ATLAS assembly hall. In the backgro...

Selection and evaluation of an ultra high vacuum gate valve for Isabelle beam line vacuum system

International Nuclear Information System (INIS)

Foerster, C.L.; McCafferty, D.

1980-01-01

A minimum of eighty-four (84) Ultra High Vacuum Gate Valves will be utilized in ISABELLE to protect proton beam lines from catastrophic vacuum failure and to provide sector isolation for maintenance requirements. The valve to be selected must function at less than 1 x 10 -11 Torr pressure and be bakeable to 300 0 C in its open or closed position. In the open position, the valve must have an RF shield to make the beam line walls appear continuous. Several proposed designs were built and evaluated. The evaluation consisted mainly of leak testing, life tests, thermal cycling, mass spectrometer analysis, and 10 -12 Torr operation. Problems with initial design and fabrication were resolved. Special requirements for design and construction were developed. This paper describes the tests on two final prototypes which appear to be the best candidates for ISABELLE operation

Phenomenological study of the QCD vacuum. Problems relevant to factorizability of four-fermion operators

International Nuclear Information System (INIS)

Zhitnitskij, A.R.

1985-01-01

The method of QCD sum rules is used here to evaluate vacuUm expectation values (VEV) for various four-fermion operators. It is found that the VEV (anti uσsub(μν) lambda sup(α)d anti d σsub(μν) lambda sup(α)u) is by a factor of 3-3.5 larger than the factorized quantity, while the VEV (anti u lambda sup(α) d anti d lambda sup(α) u) is smaller by a factor of 3-5 A by-product of the work is a phenomenological estimate for the VEV (gsup(3)fsup(abc)Gsub(μν)sup(α)Gsub(ν lambda)sup(b)Gsub(lambda μ)sup(c)) approximately equal to 0.06 GeV 6

Internal motion in high vacuum systems

Science.gov (United States)

Frank, J. M.

Three transfer and positioning mechanisms have been developed for the non-air exposed, multistep processing of components in vacuum chambers. The functions to be performed in all of the systems include ultraviolet/ozone cleaning, vacuum baking, deposition of thin films, and thermocompression sealing of the enclosures. Precise positioning of the components is required during the evaporation and sealing processes. The three methods of transporting and positioning the components were developed to accommodate the design criteria and goals of each individual system. The design philosophy, goals, and operation of the three mechanisms are discussed.

Summary compilation of shell element performance versus formulation.

Energy Technology Data Exchange (ETDEWEB)

Heinstein, Martin Wilhelm; Hales, Jason Dean (Idaho National Laboratory, Idaho Falls, ID); Breivik, Nicole L.; Key, Samuel W. (FMA Development, LLC, Great Falls, MT)

2011-07-01

This document compares the finite element shell formulations in the Sierra Solid Mechanics code. These are finite elements either currently in the Sierra simulation codes Presto and Adagio, or expected to be added to them in time. The list of elements are divided into traditional two-dimensional, plane stress shell finite elements, and three-dimensional solid finite elements that contain either modifications or additional terms designed to represent the bending stiffness expected to be found in shell formulations. These particular finite elements are formulated for finite deformation and inelastic material response, and, as such, are not based on some of the elegant formulations that can be found in an elastic, infinitesimal finite element setting. Each shell element is subjected to a series of 12 verification and validation test problems. The underlying purpose of the tests here is to identify the quality of both the spatially discrete finite element gradient operator and the spatially discrete finite element divergence operator. If the derivation of the finite element is proper, the discrete divergence operator is the transpose of the discrete gradient operator. An overall summary is provided from which one can rank, at least in an average sense, how well the individual formulations can be expected to perform in applications encountered year in and year out. A letter grade has been assigned albeit sometimes subjectively for each shell element and each test problem result. The number of A's, B's, C's, et cetera assigned have been totaled, and a grade point average (GPA) has been computed, based on a 4.0-system. These grades, combined with a comparison between the test problems and the application problem, can be used to guide an analyst to select the element with the best shell formulation.

Greenhouse effect: temperature of a metal sphere surrounded by a glass shell and heated by sunlight

International Nuclear Information System (INIS)

Nguyen, Phuc H; Matzner, Richard A

2012-01-01

We study the greenhouse effect on a model satellite consisting of a tungsten sphere surrounded by a thin spherical, concentric glass shell, with a small gap between the sphere and the shell. The system sits in vacuum and is heated by sunlight incident along the z-axis. This development is a generalization of the simple treatment of the greenhouse effect given by Kittel and Kroemer (1980 Thermal Physics (San Francisco: Freeman)) and can serve as a very simple model demonstrating the much more complex Earth greenhouse effect. Solution of the model problem provides an excellent pedagogical tool at the Junior/Senior undergraduate level.

The Effect of Forcing on Vacuum Radiation

OpenAIRE

Jones-Smith, Katherine; Mathur, Harsh; Lowenstein, Ashton

2018-01-01

Vacuum radiation has been the subject of theoretical study in both cosmology and condensed matter physics for many decades. Recently there has been impressive progress in experimental realizations as well. Here we study vacuum radiation when a field mode is driven both parametrically and by a classical source. We find that in the Heisenberg picture the field operators of the mode undergo a Bogolyubov transformation combined with a displacement, in the Schr\\"odinger picture the oscillator evol...

Shell model Monte Carlo methods

International Nuclear Information System (INIS)

Koonin, S.E.; Dean, D.J.; Langanke, K.

1997-01-01

We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; the resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo (SMMC) methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, the thermal and rotational behavior of rare-earth and γ-soft nuclei, and the calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. (orig.)

The vacuum structure of light-front φ41+1-theory

International Nuclear Information System (INIS)

Heinzl, T.; Stern, C.; Werner, E.; Zellermann, B.

1996-01-01

We discuss the vacuum structure of φ 4 -theory in 1+1 dimensions quantised on the light-front x + =0. To this end, one has to solve a non-linear, operator-valued constraint equation. It expresses that mode of the field operator having longitudinal light-front momentum equal to zero, as a function of all the other modes in the theory. We analyse whether this zero mode can lead to a non-vanishing vacuum expectation value of the field φ and thus to spontaneous symmetry breaking. In perturbation theory, we get no symmetry breaking. If we solve the constraint, however, non-perturbatively, within a mean-field type Fock ansatz, the situation changes: while the vacuum state itself remains trivial, we find a non-vanishing vacuum expectation value above a critical coupling. Exactly the same result is obtained within a light-front Tamm-Dancoff approximation, if the renormalisation is done in the correct way. (orig.). With 1 fig

Walnut shells: replacement for natural gas

Energy Technology Data Exchange (ETDEWEB)

Goss, J R; Williams, R O

1977-11-01

A method of extracting useful energy from cracked walnut shells has been developed by the University of California in co-operation with Diamond/Sunsweet, Inc., and the California Energy Resources Conservation and Development Commission. The technique involves converting the shells to producer gas, a low-Btu gas in which the major combustible components are carbon monoxide (20 to 30%) and hydrogen (10 to 15%).

ERATO-code analysis of vacuum magnetic field oscillations in JT-60 divertor configuration

International Nuclear Information System (INIS)

Ozeki, Takahisa; Tokuda, Shinji; Tsunematsu, Toshihide; Ishida, Shinichi; Neyatani, Yuzuru; Itami, Kiyoshi; Azumi, Masafumi

1989-07-01

Magnetic field oscillations caused by external kink instabilities are numerically studied by using the ideal MHD stability code ERATO-J. Dependence of a spatial distribution of their amplitude and phase on aspect-ratio, beta-poloidal, shaping of conducting shell and divertor/limiter configurations is examined in detail. In the low aspect ratio plasma, the amplitude of magnetic oscillations in the inner side of the torus is larger than that in the outer. On the contrary, as the poloidal beta increases, the amplitude in the outer side of the torus becomes larger than that in the inner. In the divertor configuration, the amplitude of oscillations reduces near the X-point and the phase is locally modulated. The coherent magnetic oscillations observed in JT-60 agree well with the theoretical results, where the vacuum vessel is assumed to be an ideal conducting shell. The non-uniformity of the poloidal distribution observed in JT-60 can be explained by the combined effects of the finite beta, the X-point and the shape of shell. (author)

Production of Lunar Oxygen Through Vacuum Pyrolysis

National Research Council Canada - National Science Library

Matchett, John

2006-01-01

.... The vacuum pyrolysis method of oxygen production from lunar regolith presents a viable option for in situ propellant production because of its simple operation involving limited resources from earth...

Vacuum pumping for controlled thermonuclear reactors

International Nuclear Information System (INIS)

Watson, J.S.; Fisher, P.W.

1976-01-01

Thermonuclear reactors impose unique vacuum pumping problems involving very high pumping speeds, handling of hazardous materials (tritium), extreme cleanliness requirements, and quantitative recovery of pumped materials. Two principal pumping systems are required for a fusion reactor, a main vacuum system for evacuating the torus and a vacuum system for removing unaccelerated deuterium from neutral beam injectors. The first system must pump hydrogen isotopes and helium while the neutral beam system can operate by pumping only hydrogen isotopes (perhaps only deuterium). The most promising pumping techniques for both systems appear to be cryopumps, but different cryopumping techniques can be considered for each system. The main vacuum system will have to include cryosorption pumps cooled to 4.2 0 K to pump helium, but the unburned deuterium-tritium and other impurities could be pumped with cryocondensation panels (4.2 0 K) or cryosorption panels at higher temperatures. Since pumping speeds will be limited by conductance through the ducts and thermal shields, the pumping performance for both systems will be similar, and other factors such as refrigeration costs are likely to determine the choice. The vacuum pumping system for neutral beam injectors probably will not need to pump helium, and either condensation or higher temperature sorption pumps can be used

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

International Nuclear Information System (INIS)

McPhee, William S.

1999-01-01

The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and

Computer controlled vacuum control system for synchrotron radiation beam lines

International Nuclear Information System (INIS)

Goldberg, S.M.; Wang, C.; Yang, J.

1983-01-01

The increasing number and complexity of vacuum control systems at the Stanford Synchrotron Radiation Laboratory has resulted in the need to computerize its operations in order to lower costs and increase efficiency of operation. Status signals are transmitted through digital and analog serial data links which use microprocessors to monitor vacuum status continuously. Each microprocessor has a unique address and up to 256 can be connected to the host computer over a single RS232 data line. A FORTRAN program on the host computer will request status messages and send control messages via only one RS232 line per beam line, signal the operator when a fault condition occurs, take automatic corrective actions, warn of impending valve failure, and keep a running log of all changes in vacuum status for later recall. Wiring costs are thus greatly reduced and more status conditions can be monitored without adding excessively to the complexity of the system. Operators can then obtain status reports at various locations in the lab quickly without having to read a large number of meter and LED's

Evaluation of ISABELLE full cell ultra high vacuum system

International Nuclear Information System (INIS)

Foerster, C.L.; Briggs, J.; Chou, T.S.; Stattel, P.

1980-01-01

The ISABELLE Full Cell Vacuum System consisting of a 40 m long, by 8.8 cm diameter stainless steel tube pumped by seven pumping stations was assembled and processed for 10 -12 Torr operation. Evaluation and testing of the system and its sub-assemblies has been completed. Detail design of system components and the determination of the conditioning process was completed. The best procedure to rough pump, leak test, vacuum bake the system, condition pumps, degas gauges, turn on ion pumps and flash sublimation pumps was established. Pressures below 2 x 10 -11 Torr are now routinely achieved in normal operation of the Full Cell. This includes pump down after replacement of various components and pump down after back fill with moist unfiltered air. The techniques developed for the Full Cell will be used to build the ISABELLE Ultra High Vacuum System

Thermodynamic performance of multi-stage gradational lead screw vacuum pump

Science.gov (United States)

Zhao, Fan; Zhang, Shiwei; Sun, Kun; Zhang, Zhijun

2018-02-01

As a kind of dry mechanical vacuum pump, the twin-screw vacuum pump has an outstanding pumping performance during operation, widely used in the semiconductor industry. Compared with the constant lead screw (CLS) vacuum pump, the gradational lead screw (GLS) vacuum pump is more popularly applied in recent years. Nevertheless, not many comparative studies on the thermodynamic performance of GLS vacuum pump can be found in the literature. Our study focuses on one type of GLS vacuum pump, the multi-stage gradational lead screw (MGLS) vacuum pump, gives a detailed description of its construction and illustrates it with the drawing. Based on the structural analysis, the thermodynamic procedure is divided into four distinctive processes, including sucking process, transferring (compressing) process, backlashing process and exhausting process. The internal mechanism of each process is qualitatively illustrated and the mathematical expressions of seven thermodynamic parameters are given under the ideal situation. The performance curves of MGLS vacuum pump are plotted by MATLAB software and compared with those of the CLS vacuum pump in the same case. The results can well explain why the MGLS vacuum pump has more favorable pumping performance than the CLS vacuum pump in saving energy, reducing noise and heat dissipation.

Thermal Vacuum Integrated System Test at B-2

Science.gov (United States)

Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.

2012-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Space Propulsion Research Facility, commonly referred to as B-2, is NASA s third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility during pump down of the vacuum chamber, operation of the liquid nitrogen heat sink (or cold wall) and the infrared lamp array. A vacuum level of 1.3x10(exp -4)Pa (1x10(exp -6)torr) was achieved. The heat sink provided a uniform temperature environment of approximately 77 K (140deg R) along the entire inner surface of the vacuum chamber. The recently rebuilt and modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m at a chamber diameter of 6.7 m (22 ft) and along 11 m (36 ft) of the chamber s cylindrical vertical interior. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface. The data acquired matched pretest predictions and demonstrated system functionality.

The JET vacuum interspace system

International Nuclear Information System (INIS)

Orchard, J.; Scales, S.

1999-01-01

In the past JET has suffered from a number of vacuum leaks on components such as bellows, windows and feedthroughs due, in part, to the adverse conditions, including high mechanical forces, which may prevail during plasma operation. Therefore before the recent Tritium experiments on JET it was deemed prudent to manufacture and install items with a secondary containment or interspace in order to minimise the effect of failure of the primary vacuum barrier on both the leak integrity of the machine and the outcome of the experiments. This paper describes the philosophy, logistics, method and implementation of an integrated connection and monitoring system on the 330 interspaces currently in position on the JET machine. Using the JET leak database comparisons are drawn of leak failure rates of the components allied to the number of operational hours, prior to the system being present and after installation and commissioning, and the case of detection compared to the previous situation. An argument is also presented on the feasibility and adaptability of this system to any large complex machine and the benefits to be obtained in reduction of leaks and operational down time. (author)

Multiple (Two) Met Bel 601 In Series Ultimate Vacuum Testing

Energy Technology Data Exchange (ETDEWEB)

Restivo, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-09-30

SRNL Environmental and Chemical Process Technology (E&CPT) was requested to perform testing of vacuum pumps per a verbal request from the Customer, SRNL Hydrogen Processing Technology. Tritium Operations is currently having difficulties procuring the Normetex™® Model 15 m³/hr (9 CFM) vacuum pump (formerly Normetex Pompes, now Eumeca_SARL). One possible solution proposed by Hydrogen Processing Technology personnel is to use two Senior Aerospace Metal Bellows MB-601 vacuum pumps piped with the heads in series, and the pumps in series (Figure 1 below). This memorandum documents the ultimate vacuum testing that was performed to determine if this concept was a viable alternate vacuum pump strategy. This testing dovetails with previous pump evaluations documented in references 1 and 2.

Actively-stabilized photomultiplier tube base for vacuum operation

International Nuclear Information System (INIS)

Bryan, M.A; Morris, C.L.; Idzorek, G.C.

1992-01-01

An actively stabilized photomultiplier tube (PMT) base design for an Amperex XP-2262B PMT is described. Positive-negative-positive transistors are used as low-impedance current sources to maintain constant voltages on the last three dynodes. This technique results in a highly stable, low-power tube base ideal for use with low-duty-factor beams, such as those found at the Clinton P. Anderson Meson Physics Facility. Furthermore, because of the low power usage of this large design, these bases can be sealed in a heat-conductive, electrically insulating material and used in a vacuum

LHC : The World's Largest Vacuum Systems being commissioned at CERN

CERN Document Server

Jiménez, J M

2008-01-01

When it switches on in 2008, the 26.7 km Large Hadron Collider (LHC) at CERN, will have the world's largest vacuum system operating over a wide range of pressures and employing an impressive array of vacuum technologies. This system is composed by 54 km of UHV vacuum for the circulating beams and 50 km of insulation vacuum around the cryogenic magnets and the liquid helium transfer lines. Over the 54 km of UHV beam vacuum, 48 km of this are at cryogenic temperature (1.9 K). The remaining 6 km of beam vacuum containing the insertions for "cleaning" the proton beams, radiofrequency cavities for accelerating the protons as well as beam-monitoring equipment is at ambient temperature and uses non-evaporable getter (NEG) coatings - a vacuum technology that was born and industrialized at CERN. The pumping scheme is completed using 780 ion pumps to remove noble gases and to provide pressure interlocks to the 303 vacuum safety valves. Pressure readings are provided by 170 Bayard-Alpert gauges and 1084 gauges (Pirani a...

Design concept of conducting shell and in-vessel components suitable for plasma vertical stability and remote maintenance scheme in DEMO reactor

Energy Technology Data Exchange (ETDEWEB)

Utoh, Hiroyasu, E-mail: uto.hiroyasu@jaea.go.jp [Japan Atomic Energy Agency, Obuchi, Rokkasho-mura, Aomori-ken 039-3212 (Japan); International Fusion Energy Research Centre, 2-166, Obuchi, Rokkasho, Aomori 039-3212 (Japan); Takase, Haruhiko [Japan Atomic Energy Agency, Obuchi, Rokkasho-mura, Aomori-ken 039-3212 (Japan); International Fusion Energy Research Centre, 2-166, Obuchi, Rokkasho, Aomori 039-3212 (Japan); Sakamoto, Yoshiteru; Tobita, Kenji [Japan Atomic Energy Agency, Obuchi, Rokkasho-mura, Aomori-ken 039-3212 (Japan); Mori, Kazuo; Kudo, Tatsuya [Japan Atomic Energy Agency, Obuchi, Rokkasho-mura, Aomori-ken 039-3212 (Japan); International Fusion Energy Research Centre, 2-166, Obuchi, Rokkasho, Aomori 039-3212 (Japan); Someya, Youji; Asakura, Nobuyuki; Hoshino, Kazuo; Nakamura, Makoto; Tokunaga, Shinsuke [Japan Atomic Energy Agency, Obuchi, Rokkasho-mura, Aomori-ken 039-3212 (Japan)

2016-02-15

Highlights: • Conceptual design of in-vessel component including conducting shell has been investigated. • The conducting shell design for plasma vertical stability was clarified from the plasma vertical stability analysis. • The calculation results showed that the double-loop shell has the most effect on plasma vertical stability. - Abstract: In order to realize a feasible DEMO, we designed an in-vessel component including the conducting shell. The project is affiliated with the broader approach DEMO design activities and is conceptualized from a plasma vertical stability and engineering viewpoint. The dependence of the plasma vertical stability on the conducing shell parameters and the electromagnetic force at plasma disruption were investigated in numerical simulations (programmed in the 3D eddy current analysis code and a plasma position control code). The simulations assumed the actual shape and position of the vacuum vessel and in-vessel components. The plasma vertical stability was most effectively maintained by the double-loop shell.

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

International Nuclear Information System (INIS)

McPhee, William S.

2001-01-01

The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites

Mirror Fusion vacuum technology developments

International Nuclear Information System (INIS)

Batzer, T.H.; Call, W.R.

1983-01-01

Magnetic Mirror Fusion experiments, such as MFTF-B+T (Mirror Fusion Test Facility-B, Tritium Upgrade) and foreseeable follow-on devices, have operational and maintenance requirements that have not yet been fully demonstrated. Among those associated with vacuum technology are the very-high continuous-pumping speeds, 10 7 to 10 8 l/s for D 2 , T 2 and, to a lesser extent, He; the early detection of water leaks from the very-high heat-flux neutral-beam dumps and the detection and location of leaks in the superconducting magnets not protected by guard vacuums. Possible solutions to these problems have been identified and considerable progress has been made toward successfully demonstrating their feasibility

Mirror fusion vacuum technology developments

International Nuclear Information System (INIS)

Batzer, T.H.; Call, W.R.

1983-01-01

Magnetic Mirror Fusion experiments, such as MFTF-B+T (Mirror Fusion Test Facility-B, Tritium Upgrade) and foreseeable follow-on devices, have operational and maintenance requirements that have not yet been fully demonstrated. Among those associated with vacuum technology are the very-high continuous-pumping speeds, 10 7 to 10 8 l/s for D 2 , T 2 and, to a lesser extent, He; the early detection of water leaks from the very-high heat-flux neutral-beam dumps and the detection and location of leaks in the superconducting magnets not protected by guard vacuums. Possible solutions to these problems have been identified and considerable progress has been made toward successfully demonstrating their feasibility

Multi-scenario evaluation and specification of electromagnetic loads on ITER vacuum vessel

International Nuclear Information System (INIS)

Rozov, Vladimir; Martinez, J.-M.; Portafaix, C.; Sannazzaro, G.

2014-01-01

Highlights: • We present the results of multi-scenario analysis of EM loads on ITER vacuum vessel (VV). • The differentiation of models provides the economic way to perform big amount of calculations. • Functional approximation is proposed for distributed data/FE/numerical results specification. • Examples of specification of the load profiles by trigonometric polynomials (DHT) are given. • Principles of accounting for toroidal asymmetry at EM interactions in tokamak are considered. - Abstract: The electro-magnetic (EM) transients cause mechanical forces, which represent one of the most critical loads for the ITER vacuum vessel (VV). The paper is focused on the results of multi-scenario analysis and systematization of these EM loads, including specifically addressed pressures on shells and the net vertical force. The proposed mathematical model and computational technology, based on the use of integral parameters and operational analysis methods, enabled qualitative and quantitative analysis of the problem, time-efficient computations and systematic assessment of a large number of scenarios. The obtained estimates, found envelopes and peak values exemplify the principal loads on the VV and provide a database to support engineering load specifications. Special attention is given to the challenge of specification and documenting of the results in a form, suitable for using the data in engineering applications. The practical aspects of specification of distributed data, such as experimental and finite-element (FE) results, by analytical interpolants are discussed. The example of functional approximation of the load profiles by trigonometric polynomials based on discrete Hartley transform (DHT) is given

Multi-scenario evaluation and specification of electromagnetic loads on ITER vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Rozov, Vladimir, E-mail: vladimir.rozov@iter.org; Martinez, J.-M.; Portafaix, C.; Sannazzaro, G.

2014-10-15

Highlights: • We present the results of multi-scenario analysis of EM loads on ITER vacuum vessel (VV). • The differentiation of models provides the economic way to perform big amount of calculations. • Functional approximation is proposed for distributed data/FE/numerical results specification. • Examples of specification of the load profiles by trigonometric polynomials (DHT) are given. • Principles of accounting for toroidal asymmetry at EM interactions in tokamak are considered. - Abstract: The electro-magnetic (EM) transients cause mechanical forces, which represent one of the most critical loads for the ITER vacuum vessel (VV). The paper is focused on the results of multi-scenario analysis and systematization of these EM loads, including specifically addressed pressures on shells and the net vertical force. The proposed mathematical model and computational technology, based on the use of integral parameters and operational analysis methods, enabled qualitative and quantitative analysis of the problem, time-efficient computations and systematic assessment of a large number of scenarios. The obtained estimates, found envelopes and peak values exemplify the principal loads on the VV and provide a database to support engineering load specifications. Special attention is given to the challenge of specification and documenting of the results in a form, suitable for using the data in engineering applications. The practical aspects of specification of distributed data, such as experimental and finite-element (FE) results, by analytical interpolants are discussed. The example of functional approximation of the load profiles by trigonometric polynomials based on discrete Hartley transform (DHT) is given.

"Flat-Fish" vacuum chamber for the ISR

CERN Multimedia

CERN PhotoLab

1983-01-01

The "Flat-Fish" vacuum chamber was a very special one for the ISR beam intersection I-4, inside the Split-Field Magnet. Technical descriptions are given with pictures 7802042 and 7712182. There were several generations of this chamber. This picture was taken during the last year of ISR operation. See also 7510230X, 7511123X, 7802039, 7802041. A flat-fish type vacuum chamber was also used at I-8, inside the Open Axial Field Magnet (OAFM, experiment 807 on large transverse momentum collision products), see 7901358.

Ultra-high vacuum system of the Brookhaven National Synchrotron Light Source

Energy Technology Data Exchange (ETDEWEB)

Foerster, C.L.

1995-12-31

The rings of the National Synchrotron Light Source (NSLS) have been supplying light to numerous users for approximately a decade and we recently enjoyed a fully conditioned machine vacuum at design currents. A brief description of the X-Ray storage ring, the VUV storage ring and their current supply is given along with some of their features. The ultra-high vacuum system employed for the storage rings and their advantages for the necessary stored beam environments are discussed including, a brief history of time. After several hundred amp hours of stored beam current operation, very little improvement in machine performance was seen due to conditioning. Sections of the rings were vented, to dry nitrogen and replacement components were pre-baked and pre-argon glow conditioned prior to installation. Very little machine conditioning was needed to return to operation after recovering vacuum due to well established conditioning procedures. All straight sections in the X-Ray ring and the VUV ring have been filled with various insertion devices and most are fully operational. Each storage ring has a computer controlled total pressure and partial pressure monitoring system for the ring and its beam ports, to insure good vacuum.

NIF Double Shell outer/inner shell collision experiments

Science.gov (United States)

Merritt, E. C.; Loomis, E. N.; Wilson, D. C.; Cardenas, T.; Montgomery, D. S.; Daughton, W. S.; Dodd, E. S.; Desjardins, T.; Renner, D. B.; Palaniyappan, S.; Batha, S. H.; Khan, S. F.; Smalyuk, V.; Ping, Y.; Amendt, P.; Schoff, M.; Hoppe, M.

2017-10-01

Double shell capsules are a potential low convergence path to substantial alpha-heating and ignition on NIF, since they are predicted to ignite and burn at relatively low temperatures via volume ignition. Current LANL NIF double shell designs consist of a low-Z ablator, low-density foam cushion, and high-Z inner shell with liquid DT fill. Central to the Double Shell concept is kinetic energy transfer from the outer to inner shell via collision. The collision determines maximum energy available for compression and implosion shape of the fuel. We present results of a NIF shape-transfer study: two experiments comparing shape and trajectory of the outer and inner shells at post-collision times. An outer-shell-only target shot measured the no-impact shell conditions, while an `imaging' double shell shot measured shell conditions with impact. The `imaging' target uses a low-Z inner shell and is designed to perform in similar collision physics space to a high-Z double shell but can be radiographed at 16keV, near the viable 2DConA BL energy limit. Work conducted under the auspices of the U.S. DOE by LANL under contract DE-AC52-06NA25396.

TFTR ultrahigh-vacuum pumping system incorporating mercury diffusion pumps

International Nuclear Information System (INIS)

Sink, D.A.; Sniderman, M.

1976-06-01

The TFTR vacuum vessel will have a system of four 61 cm diameter mercury diffusion pumps to provide a base pressure in the 10 -8 to 10 -9 Torr range as well as a low impurity level within the vessel. The system, called the Torus Vacuum Pumping System (TVPS), will be employed with the aid of an occasional 250 0 C bakeout in situ as well as periodic applications of aggressive discharge cleaning. The TVPS is an ultrahigh-vacuum (UHV) system using no elastomers as well as being a closed system with respect to tritium or any tritiated gases. The backing system employing approximately 75 all-metal isolation valves is designed with the features of redundancy and flexibility employed in a variety of ways to meet the fundamental requirements and functions enumerated for the TVPS. Since the design, is one which is a modification of the conceptual design of the TVPS, those features which have changed are discussed. Calculations are presented for the major performance parameters anticipated for the TVPS and include conductances, effective pumping speeds, base pressures, operating parameters, getter pump parameters, and calculations of time constants associated with leak checking. Modifications in the vacuum pumping system for the guard regions on the twelve bellows sections are presented so that it is compatible with the main TVPS. The bellows pumping system consists of a mechanical pump unit, a zirconium aluminum getter pump unit and a residual gas analyzer. The control and management of the TVPS is described with particular attention given to providing both manual and automatic control at a local station and at the TFTR Central Control. Such operations as testing, maintenance, leak checking, startup, bakeout, and various other operations are considered in some detail. Various aspects related to normal pulsing, discharge cleaning, non-tritium operations and tritium operations are also taken into consideration. A cost estimate is presented

Vacuum system in the first operation of SuperKEKB

International Nuclear Information System (INIS)

Suetsugu, Yusuke; Shibata, Kyo; Ishibashi, Takuya; Shirai, Mitsuru; Terui, Shinji; Kanazawa, Ken-ichi; Hisamatsu, Hiromi

2017-01-01

The first (Phase-1) commissioning of SuperKEKB, an asymmetric-energy electron-positron collider at KEK, began in February 2016, after more than 5 years of upgrade work on KEKB and successfully ended in June 2016. A major task of the Phase-1 commissioning was the vacuum scrubbing of new beam pipes in anticipation of a sufficiently long beam lifetime in the next commissioning. The pressure rise per unit beam current decreased steadily with increasing beam dose, as expected. Another important task was to check the stabilities of various new vacuum components at high beam currents of approximately 1 A. The temperature increases of the bellows chambers, gate valves, connection flanges, and so on were less than several degrees at 1 A, and no serious problems were found. The effectiveness of the antechambers and TiN coating in suppressing the electron-cloud effect (ECE) in the positron ring was also confirmed. However, the ECE in the Al-alloy bellows chambers was observed where TiN had not been coated. The use of permanent magnets with an axial magnetic field of approximately 100 G successfully suppressed this effect. Pressure bursts accompanying beam losses were also frequently observed in the positron ring. The preparation for the next Phase-2 commissioning, such as the installations of new beam pipes at the collision point and of six more beam collimators, are now in progress. (author)

Influence of a high vacuum on the precise positioning using an ultrasonic linear motor.

Science.gov (United States)

Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu

2011-01-01

This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.

Influence of a high vacuum on the precise positioning using an ultrasonic linear motor

International Nuclear Information System (INIS)

Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu

2011-01-01

This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.

Shell Canada Limited 1998 annual report

International Nuclear Information System (INIS)

1999-01-01

A report of operational and financial achievements is reported. Shell Canada's Resources Division is one of Canada's largest producers of crude oil, natural gas, natural gas liquids, sulphur and bitumen. This report presents an operations review, provides consolidated financial statements, and common share information, and summarizes revenue and expenditure statements. The company was one of Canada's most profitable integrated oil and gas companies in 1998. It was the second most profitable year in the company's history for continuing operations. Oil products earnings for 1998 were a record $275 million, mostly because of strong sales volumes and increased retail market share. The company also confronted several environmental issues in 1998, including climate change and the reduction of greenhouse gases. Construction of the Sable Project, offshore Nova Scotia, continued on budget and on schedule to bring natural gas to market by early 2000. Plans for the three elements of the Oil Sands project (the Muskeg River mine in the Athabaska Region, an upgrader at Shell's Scotford site and the Corridor Pipeline) proceeded on schedule. The Caroline complex made its expected contribution to the company's overall performance. Improved seismic technology helped to add new reserves through Shell's interest in wells in southern Alberta. Exploration activity in northeastern British Columbia and northern Alberta produced encouraging results. The work will continue in 1999. The company plans to invest some 4.9 billion dollars over the next five years in capital expenditures. Shell remains committed to the Voluntary Challenge and Registry Program. Annual reduction of CO 2 emissions increased by an estimated 800,000 tonnes

Investigation of Thermal and Vacuum Transients on the LHC Prototype Magnet String

CERN Document Server

Cruikshank, P; Riddone, G; Tavian, L

1996-01-01

The prototype magnet string, described in a companion paper, is a full-scale working model of a 50-m length of the future Large Hadron Collider (LHC), CERN's new accelerator project, which will use high-field superconducting magnets operating below 2 K in superfluid helium. As such, it provides an excellent test bed for practising standard operating modes of LHC insulation vacuum and cryogenics, as well as for experimentally assessing accidental behaviour and failure modes, and thus verifying design calculations. We present experimental investigation of insulation vacuum pumpdown, magnet forced-flow cooldown and warmup, and evolution of residual vacuum pressures and temperatures in natural warmup, as well as catastrophic loss of insulation vacuum. In all these transient modes, experimental results are compared with simulated behaviour, using a non-linear, one-dimensional thermal model of the magnet string.

Tests of a vacuum breaker for the FTU commutation system

International Nuclear Information System (INIS)

Andreani, R.; Lovisetto, L.; Cornago, F.

1984-01-01

A two poles vacuum breaker, equipped with saturable inductances and capacitor banks to produce an artificial current zero, appears the most suitable solution to satisfy these requirements with high reliability of operation and limited maintenance. Two series of tests have been conducted to evaluate the performance and reliability of the system and in particular the erosion of the electrodes as a function of number of operations. The test results have been very satisfactory. At least 1000 full power pulses can be envisaged before replacing the vacuum bottles. (author)

Vacuum system of SST-1 Tokamak

International Nuclear Information System (INIS)

Khan, Ziauddin; Pathan, Firozkhan; George, Siju; Semwal, Pratibha; Dhanani, Kalpesh; Paravastu, Yuvakiran; Thankey, Prashant; Ramesh, Gattu; Himabindu, Manthena; Pradhan, Subrata

2013-01-01

Highlights: ► Air leaks developed during ongoing SST-1 cooldown campaign were detected online using RGA. ► The presence of N 2 and O 2 gases with the ratio of their partial pressures with ∼3.81:1 confirmed the air leaks. ► Baking of SST-1 was done efficiently by flowing hot N 2 gas in C-channels welded on inner surfaces without any problem. ► In-house fabricated demountable bull nose couplers were demonstrated for high temperature and pressure applications. ► Cryopumping effect was observed when liquid helium cooled superconducting magnets reached below 63 K. -- Abstract: Vacuum chambers of Steady State Superconducting (SST-1) Tokamak comprises of the vacuum vessel and the cryostat. The plasma will be confined inside the vacuum vessel while the cryostat houses the superconducting magnet systems (TF and PF coils), LN 2 cooled thermal shields and hydraulics for these circuits. The vacuum vessel is an ultra-high (UHV) vacuum chamber while the cryostat is a high-vacuum (HV) chamber. In order to achieve UHV inside the vacuum vessel, it would be baked at 150 °C for longer duration. For this purpose, U-shaped baking channels are welded inside the vacuum vessel. The baking will be carried out by flowing hot nitrogen gas through these channels at 250 °C at 4.5 bar gauge pressure. During plasma operation, the pressure inside the vacuum vessel will be raised between 1.0 × 10 −4 mbar and 1.0 × 10 −5 mbar using piezoelectric valves and control system. An ultimate pressure of 4.78 × 10 −6 mbar is achieved inside the vacuum vessel after 100 h of pumping. The limitation is due to the development of few leaks of the order of 10 −5 mbar l/s at the critical locations of the vacuum vessel during baking which was confirmed with the presence of nitrogen gas and oxygen gas with the ratio of ∼3.81:1 indicating air leak. Similarly an ultimate vacuum of 2.24 × 10 −5 mbar is achieved inside the cryostat. Baking of the vacuum vessel up to 110 °C with ±10 �

Design and performance of main vacuum pumping system of SST-1 Tokamak

Energy Technology Data Exchange (ETDEWEB)

Khan, Ziauddin, E-mail: ziauddin@ipr.res.in; Pathan, Firozkhan; George, Siju; Dhanani, Kalpesh; Paravastu, Yuvakiran; Semwal, Pratibha; Pradhan, Subrata

2014-01-15

Highlights: •SST-1 Tokamak was successfully commissioned. •Vacuum vessel and cryostat were pumped down to 6.3 × 10{sup −7} mbar and 1.3 × 10{sup −5} mbar. •Leaks developed during baking were detected in-situ by RGA and confirmed later on. •Cryo-pumping effect was observed when LN2 thermal shields reached below 273 K. •Non-standard aluminum wire-seals have shown leak tightness < 1.0 × 10{sup −9} mbar l/s. -- Abstract: Steady-state Superconducting Tokamak (SST-1) was installed and it is commissioning for overall vacuum integrity, magnet systems functionality in terms of successful cool down to 4.5 K and charging up to 10 kA current was started from August 2012. Plasma operation of 100 kA current for more than 100 ms was also envisaged. It is comprised of vacuum vessel (VV) and cryostat (CST). Vacuum vessel, an ultra-high (UHV) vacuum chamber with net volume of 23 m{sup 3} was maintained at the base pressure of 6.3 × 10{sup −7} mbar for plasma confinement. Cryostat, a high-vacuum (HV) chamber with empty volume 39 m{sup 3} housing superconducting magnet system, bubble thermal shields and hydraulics for these circuits, maintained at 1.3 × 10{sup −5} mbar in order to provide suitable environment for these components. In order to achieve these ultimate vacuums, two numbers of turbo-molecular pumps (TMP) are installed in vacuum vessel while three numbers of turbo-molecular pumps are installed in cryostat. Initial pumping of both the chambers was carried out by using suitable Roots pumps. PXI based real time controlled system is used for remote operation of the complete pumping operation. In order to achieve UHV inside the vacuum vessel, it was baked at 150 °C for longer duration. Aluminum wire-seals were used for all non-circular demountable ports and a leak tightness < 1.0 × 10{sup −9} mbar l/s were achieved.

Design of large aperture, low mass vacuum windows

International Nuclear Information System (INIS)

Leonhardt, W.J.; Mapes, M.

1993-01-01

Large vacuum vessels are employed downstream of fixed targets in High Energy Physics experiments to provide a long path for particles to traverse without interacting with air molecules. These vessels generally have a large aperture opening known as a vacuum window which employs a thin membrane to preserve the vacuum environment yet allows the particles to pass through with a minimal effect on them. Several large windows have been built using a composite of Kevlar/Mylar including circular windows to a diameter of 96.5 cm and rectangular windows up to 193 cm x 86 cm. This paper describes the design, fabrication, testing and operating experience with these windows and relates the actual performance to theoretical predictions

Combined electron beam and vacuum ARC melting for barrier tube shell material

International Nuclear Information System (INIS)

Worcester, S.A.; Woods, C.R.

1989-01-01

This patent describes a process of the type wherein zirconium tetrachloride is reduced to produce a metallic zirconium sponge. The sponge is distilled to generally remove residual magnesium and magnesium chloride, and the distilled sponge is melted to produce an ingot, the improvement for making a non-crystal bar material for use in lining the interior of zirconium alloy fuel element cladding which comprises: a. forming the distilled sponge into a consumable electrode; b. melting the consumable electrode in a multiple swept beam electron furnace with a feed rate between 1 and 20 inches per hour to form an intermediate ingot; and c. vacuum arc melting the intermediate ingot to produce a homogeneous final ingot, having 50-500 ppm iron

Vacuum nanoelectronic devices novel electron sources and applications

CERN Document Server

Evtukh, Anatoliy; Yilmazoglu, Oktay; Mimura, Hidenori; Pavlidis, Dimitris

2015-01-01

Introducing up-to-date coverage of research in electron field emission from nanostructures, Vacuum Nanoelectronic Devices outlines the physics of quantum nanostructures, basic principles of electron field emission, and vacuum nanoelectronic devices operation, and offers as insight state-of-the-art and future researches and developments.  This book also evaluates the results of research and development of novel quantum electron sources that will determine the future development of vacuum nanoelectronics. Further to this, the influence of quantum mechanical effects on high frequency vacuum nanoelectronic devices is also assessed. Key features: In-depth description and analysis of the fundamentals of Quantum Electron effects in novel electron sources. Comprehensive and up-to-date summary of the physics and technologies for THz sources for students of physical and engineering specialties and electronics engineers. Unique coverage of quantum physical results for electron-field emission and novel electron sourc...

Analysis of anisotropic shells containing flowing fluid

International Nuclear Information System (INIS)

Lakis, A.A.

1983-01-01

A general theory for the dynamic analysis of anisotropic thin cylindrical shells containing flowing fluid is presented. The shell may be uniform or non-uniform, provided it is geometrically axially symmetric. This is a finite- element theory, using cylindrical finite elements, but the displacement functions are determined by using classical shell theory. A new solution of the wave equation of the liquid finite element leads to an expression of the fluid pressure, p, as a function of the nodal displacements of the element and three operative forces (inertia, centrifugal and Coriolis) of the moving fluid. (Author) [pt

The New Control System for the Vacuum of ISOLDE

CERN Document Server

Blanchard, S; Bernard, FB; Blanco, E; Gomes, P; Vestergard, H; Willeman, D

2011-01-01

The On-Line Isotope Mass Separator (ISOLDE) is a facility dedicated to the production of radioactive ion beams for nuclear and atomic physics. From ISOLDE vacuum sectors to the pressurized exhaust gas storage tanks there are up to five stages of pumping for a total of more than one hundred pumps including turbo-molecular, cryogenic, dry, membrane and oil pumps. The ISOLDE vacuum control system is critical; the volatile radioactive elements present in the exhaust gases and the high and ultra high vacuum pressure specifications require a complex control and interlock system. This paper describes the reengineering of the control system developed using the CERN UNICOS-CPC framework. An additional challenge has been the usage of the UNICOS-CPC in a vacuum domain for the first time. The process automation provides multiple operating modes (rough pumping, bake-out, high vacuum pumping, regeneration for cryo-pumped sectors, venting, etc). The control system is composed of local controllers driven by...

Vacuum Systems Consensus Guideline for Department of Energy Accelerator Laboratories

Energy Technology Data Exchange (ETDEWEB)

Casey,R.; Haas, E.; Hseuh, H-C.; Kane, S.; Lessard, E.; Sharma, S.; Collins, J.; Toter, W. F.; Olis, D. R.; Pushka, D. R.; Ladd, P.; Jobe, R. K.

2008-09-09

Vacuum vessels, including evacuated chambers and insulated jacketed dewars, can pose a potential hazard to equipment and personnel from collapse, rupture due to back-fill pressurization, or implosion due to vacuum window failure. It is therefore important to design and operate vacuum systems in accordance with applicable and sound engineering principles. 10 CFR 851 defines requirements for pressure systems that also apply to vacuum vessels subject to back-fill pressurization. Such vacuum vessels are potentially subject to the requirements of the American Society of Mechanical Engineers (ASME) Pressure Vessel Code Section VIII (hereafter referred to as the 'Code'). However, the scope of the Code excludes vessels with internal or external operating pressure that do not exceed 15 pounds per square inch gauge (psig). Therefore, the requirements of the Code do not apply to vacuum systems provided that adequate pressure relief assures that the maximum internal pressure within the vacuum vessel is limited to less than 15 psig from all credible pressure sources, including failure scenarios. Vacuum vessels that cannot be protected from pressurization exceeding 15 psig are subject to the requirements of the Code. 10 CFR 851, Appendix A, Part 4, Pressure Safety, Section C addresses vacuum system requirements for such cases as follows: (c) When national consensus codes are not applicable (because of pressure range, vessel geometry, use of special materials, etc.), contractors must implement measures to provide equivalent protection and ensure a level of safety greater than or equal to the level of protection afforded by the ASME or applicable state or local code. Measures must include the following: (1) Design drawings, sketches, and calculations must be reviewed and approved by a qualified independent design professional (i.e., professional engineer). Documented organizational peer review is acceptable. (2) Qualified personnel must be used to perform examinations

Vacuum system for the Stanford-LBL storage ring (PEP)

International Nuclear Information System (INIS)

Bostic, D.; Cummings, U.; Dean, N.; Jeong, B.; Jurow, J.

1975-03-01

The vacuum system for PEP will be similar in design, construction and operation to the system currently in operation at SPEAR. There will, of course, be quantitative differences since the closed path of PEP will be 10 times longer than the SPEAR path. Some qualitative differences will also arise since the radiated synchrotron power for PEP will be about 13 times greater than for SPEAR giving rise to an increased linear power density incident on the chamber wall. Other differences arise from the higher energy spectrum of the synchrotron radiation. The SPEAR vacuum system has been in operation since April 1972 and has proven satisfactory in design, construction and operation. The chamber has been subject to synchrotron radiation for approximately 300 ampere-hours and beam lifetimes are now more than several hours. The details of the PEP design and the SPEAR operating experience will be further discussed in this paper. 1 ref., 4 figs

Low mass large aperture vacuum window development at CEBAF

International Nuclear Information System (INIS)

Keppel, C.

1995-01-01

Large aperture low mass vacuum windows are being developed for the HMS (High Momentum Spectrometer) and SOS (Short Orbit Spectrometer) spectrometers in Hall C at CEBAF. Because multiple scattering degrades the performance of a spectrometer it is important that the volume be evacuated and that the entrance and exit windows be as low mass as possible. The material used for such windows must be thin and light enough so as to have minimum effect of the beam, and at the same time, be thick and strong enough to operate reliably and safely. To achieve these goals, composite vacuum windows have been constructed of a thin sheet of Mylar with a reinforcing fabric. Reinforcing fabrics such as Kevlar and Spectra are available with tensile strengths significantly greater than that of Mylar. A thin layer of Myler remains necessary since the fabrics cannot achieve any sort of vacuum seal. The design, fabrication, testing, and operating experience with such composite windows for the Hall C spectrometers will be discussed

Reversed field pinch operation with intelligent shell feedback control in EXTRAP T2R

Science.gov (United States)

Brunsell, P. R.; Kuldkepp, M.; Menmuir, S.; Cecconello, M.; Hedqvist, A.; Yadikin, D.; Drake, J. R.; Rachlew, E.

2006-11-01

Discharges in the thin shell reversed field pinch (RFP) device EXTRAP T2R without active feedback control are characterized by growth of non-resonant m = 1 unstable resistive wall modes (RWMs) in agreement with linear MHD theory. Resonant m = 1 tearing modes (TMs) exhibit initially fast rotation and the associated perturbed radial fields at the shell are small, but eventually TMs wall-lock and give rise to a growing radial field. The increase in the radial field at the wall due to growing RWMs and wall-locked TMs is correlated with an increase in the toroidal loop voltage, which leads to discharge termination after 3-4 wall times. An active magnetic feedback control system has been installed in EXTRAP T2R. A two-dimensional array of 128 active saddle coils (pair-connected into 64 independent m = 1 coils) is used with intelligent shell feedback control to suppress the m = 1 radial field at the shell. With feedback control, active stabilization of the full toroidal spectrum of 16 unstable m = 1 non-resonant RWMs is achieved, and TM wall locking is avoided. A three-fold extension of the pulse length, up to the power supply limit, is observed. Intelligent shell feedback control is able to maintain the plasma equilibrium for 10 wall times, with plasma confinement parameters sustained at values comparable to those obtained in thick shell devices of similar size.

Reversed field pinch operation with intelligent shell feedback control in EXTRAP T2R

International Nuclear Information System (INIS)

Brunsell, P.R.; Kuldkepp, M.; Menmuir, S.; Cecconello, M.; Hedqvist, A.; Yadikin, D.; Drake, J.R.; Rachlew, E.

2006-01-01

Discharges in the thin shell reversed field pinch (RFP) device EXTRAP T2R without active feedback control are characterized by growth of non-resonant m = 1 unstable resistive wall modes (RWMs) in agreement with linear MHD theory. Resonant m = 1 tearing modes (TMs) exhibit initially fast rotation and the associated perturbed radial fields at the shell are small, but eventually TMs wall-lock and give rise to a growing radial field. The increase in the radial field at the wall due to growing RWMs and wall-locked TMs is correlated with an increase in the toroidal loop voltage, which leads to discharge termination after 3-4 wall times. An active magnetic feedback control system has been installed in EXTRAP T2R. A two-dimensional array of 128 active saddle coils (pair-connected into 64 independent m = 1 coils) is used with intelligent shell feedback control to suppress the m = 1 radial field at the shell. With feedback control, active stabilization of the full toroidal spectrum of 16 unstable m = 1 non-resonant RWMs is achieved, and TM wall locking is avoided. A three-fold extension of the pulse length, up to the power supply limit, is observed. Intelligent shell feedback control is able to maintain the plasma equilibrium for 10 wall times, with plasma confinement parameters sustained at values comparable to those obtained in thick shell devices of similar size

Vacuum system design considerations of the Los Alamos Accelerator Test Stand (ATS)

International Nuclear Information System (INIS)

Wilson, N.G.

1986-01-01

The accelerator test stand (ATS), in operation at the Los Alamos National Laboratory, includes a hydrogen ion source, low- and high-energy beam-transport sections, and a 425-MHz radio-frequency quadrupole (RFQ) linear accelerator. A 425-MHz drift-tube linac (DTL) and a powered ''buncher'' matching section have been constructed and will be installed on the ATS. The vacuum systems required for the various sections of the ATS are designed to provide: (1) high gas-load capability, as required in the ion source, and (2) high-vacuum capability in the high-power, radio-frequency accelerator sections (where fast vacuum-system response time is of importance) through the use of distributed, differential pumping as a principal vacuum-system feature. This paper describes properties of accelerator materials, vacuum-systems engineering and analysis, vacuum equipment used, and ATS vacuum-system performance

Safety Analysis in Large Volume Vacuum Systems Like Tokamak: Experiments and Numerical Simulation to Analyze Vacuum Ruptures Consequences

Directory of Open Access Journals (Sweden)

A. Malizia

2014-01-01

Full Text Available The large volume vacuum systems are used in many industrial operations and research laboratories. Accidents in these systems should have a relevant economical and safety impact. A loss of vacuum accident (LOVA due to a failure of the main vacuum vessel can result in a fast pressurization of the vessel and consequent mobilization dispersion of hazardous internal material through the braches. It is clear that the influence of flow fields, consequence of accidents like LOVA, on dust resuspension is a key safety issue. In order to develop this analysis an experimental facility is been developed: STARDUST. This last facility has been used to improve the knowledge about LOVA to replicate a condition more similar to appropriate operative condition like to kamaks. By the experimental data the boundary conditions have been extrapolated to give the proper input for the 2D thermofluid-dynamics numerical simulations, developed by the commercial CFD numerical code. The benchmark of numerical simulation results with the experimental ones has been used to validate and tune the 2D thermofluid-dynamics numerical model that has been developed by the authors to replicate the LOVA conditions inside STARDUST. In present work, the facility, materials, numerical model, and relevant results will be presented.

Quality Management of CERN Vacuum Controls

CERN Document Server

Antoniotti, F; Fortescue-Beck, E; Gama, J; Gomes, P; Le Roux, P; Pereira, H; Pigny, G

2014-01-01

The vacuum controls Section (TE-VSC-ICM) is in charge of the monitoring, maintenance and consolidation of the control systems of all accelerators and detectors in CERN; this represents 6 000 instruments distributed along 128 km of vacuum chambers, often of heterogeneous architectures and of diverse technical generations. In order to improve the efficiency of the services provided by ICM, to vacuum experts and to accelerator operators, a Quality Management Plan is being put into place. The first step was the standardization of the naming convention across different accelerators. The traceability of problems, requests, repairs, and other actions, has also been put into place (VTL). This was combined with the effort to identify each individual device by a coded label, and register it in a central database (MTF). Occurring in parallel, was the gathering of old documents and the centralization of information concerning architectures, procedures, equipment and settings (EDMS). To describe the topology of control c...

Vacuum engineering for fusion research and fusion reactors

International Nuclear Information System (INIS)

Pittenger, L.C.

1976-01-01

The following topics are described: (1) surface pumping by cryogenic condensation, (2) operation of large condensing cryopumps, (3) pumping for large fusion experiments, and (4) vacuum technology for fusion reactors

Vacuum-assisted drainage in cardiopulmonary bypass: advantages and disadvantages.

Science.gov (United States)

Carvalho Filho, Elio Barreto de; Marson, Fernando Augusto de Lima; Costa, Loredana Nilkenes Gomes da; Antunes, Nilson

2014-01-01

Systematic review of vacuum assisted drainage in cardiopulmonary bypass, demonstrating its advantages and disadvantages, by case reports and evidence about its effects on microcirculation. We conducted a systematic search on the period 1997-2012, in the databases PubMed, Medline, Lilacs and SciELO. Of the 70 selected articles, 26 were included in the review. Although the vacuum assisted drainage has significant potential for complications and requires appropriate technology and professionalism, prevailed in literature reviewed the concept that vacuum assisted drainage contributed in reducing the rate of transfusions, hemodilutions, better operative field, no significant increase in hemolysis, reduced complications surgical, use of lower prime and of smaller diameter cannulas.

Design of large aperture, low mass vacuum windows

International Nuclear Information System (INIS)

Leonhardt, W.J.; Mapes, M.

1993-01-01

Large vacuum vessels are employed downstream of fixed targets in High Energy Physics experiments to provide a long path for particles to transverse without interacting with air molecules. These vessels generally have a large aperture opening known as a open-quotes vacuum windowclose quotes which employs a thin membrane to preserve the vacuum environment yet allows the particles to pass through with a minimal effect on them. Several large windows have been built using a composite of Kevlar/Mylar including circular windows to a diameter of 96.5 cm and rectangular windows up to 193 cm x 86 cm. This paper describes the design, fabrication, testing and operating experience with these windows and relates the actual performance to theoretical predictions

Vacuum system of SST-1 Tokamak

Energy Technology Data Exchange (ETDEWEB)

Khan, Ziauddin, E-mail: ziauddin@ipr.res.in [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India); Pathan, Firozkhan; George, Siju; Semwal, Pratibha; Dhanani, Kalpesh; Paravastu, Yuvakiran; Thankey, Prashant; Ramesh, Gattu; Himabindu, Manthena; Pradhan, Subrata [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India)

2013-10-15

Highlights: ► Air leaks developed during ongoing SST-1 cooldown campaign were detected online using RGA. ► The presence of N{sub 2} and O{sub 2} gases with the ratio of their partial pressures with ∼3.81:1 confirmed the air leaks. ► Baking of SST-1 was done efficiently by flowing hot N{sub 2} gas in C-channels welded on inner surfaces without any problem. ► In-house fabricated demountable bull nose couplers were demonstrated for high temperature and pressure applications. ► Cryopumping effect was observed when liquid helium cooled superconducting magnets reached below 63 K. -- Abstract: Vacuum chambers of Steady State Superconducting (SST-1) Tokamak comprises of the vacuum vessel and the cryostat. The plasma will be confined inside the vacuum vessel while the cryostat houses the superconducting magnet systems (TF and PF coils), LN{sub 2} cooled thermal shields and hydraulics for these circuits. The vacuum vessel is an ultra-high (UHV) vacuum chamber while the cryostat is a high-vacuum (HV) chamber. In order to achieve UHV inside the vacuum vessel, it would be baked at 150 °C for longer duration. For this purpose, U-shaped baking channels are welded inside the vacuum vessel. The baking will be carried out by flowing hot nitrogen gas through these channels at 250 °C at 4.5 bar gauge pressure. During plasma operation, the pressure inside the vacuum vessel will be raised between 1.0 × 10{sup −4} mbar and 1.0 × 10{sup −5} mbar using piezoelectric valves and control system. An ultimate pressure of 4.78 × 10{sup −6} mbar is achieved inside the vacuum vessel after 100 h of pumping. The limitation is due to the development of few leaks of the order of 10{sup −5} mbar l/s at the critical locations of the vacuum vessel during baking which was confirmed with the presence of nitrogen gas and oxygen gas with the ratio of ∼3.81:1 indicating air leak. Similarly an ultimate vacuum of 2.24 × 10{sup −5} mbar is achieved inside the cryostat. Baking of the

Improved simulation design factors for unconventional crude vacuum units : cracked gas make and stripping section performance

Energy Technology Data Exchange (ETDEWEB)

Remesat, D. [Koch-Glitsch Canada LP, Calgary, AB (Canada)

2008-10-15

Operating data for unconventional heavy oil vacuum crude units were reviewed in order to optimize the design of vacuum columns. Operational data from heavy crude vacuum units operating with stripping and velocity were used to investigate the application of a proven vacuum distillation tower simulation topology designed for use with heavy oil and bitumen upgrader feeds. Design factors included a characterization of the crude oils or bitumens processed in the facility; the selection of thermodynamic models; and the non-equilibrium simulation topology. Amounts of generated cracked gas were calculated, and entrainment and stripping section performance was evaluated. Heater designs for ensuring the even distribution of heat flux were discussed. Data sets from vacuum units processing crude oils demonstrated that the amount of offgas flow increased as the transfer line temperature increased. The resulting instability caused increased coke generation and light hydrocarbon formation. Results also indicated that overhead vacuum ejector design and size as well as heat transfer capabilities of quench and pumparound zones must be considered when designing vacuum column units. Steam stripping lowered hydrocarbon partial pressure to allow materials to boil at lower temperatures. It was concluded that setting appropriate entrainment values will ensure the accuracy of sensitivity analyses for transfer line designs, inlet feed devices, and wash bed configurations. 9 refs., figs.

Improvement of operational properties of shell limestone building materials by polysulfide solution impregnation

Directory of Open Access Journals (Sweden)

MASSALIMOV Ismail Alexandrovich

2017-06-01

Full Text Available The data of studies on the effectiveness of impregnation with polysulfide solutions of shell limestone used as facing and wall material, as well as for the manufacture of road products are presented. Modification of the limestone with the impregnating composition «Akvastat» created by the authors which is sulfur-containing water-based solution of calcium polysulfide containing alcohols and surfactants, can significantly reduce water absorption and increase durability of limestone. Impregnating composition on the basis of calcium polysulfide possesses density of 1.22–1.24 g/cm3, the infiltrant penetrates into the pore structure of limestone to a depth of 4 cm or more, depending on the density and structure of the sample. While the material is drying, sulfur nanoparticles are crystallized from the polysulfide solution in its pores. They partially fill pore space and form protective durable insoluble hydrophobic coating that impedes the penetration of water into the pores of the limestone, but preserves its vapor permeability, which is important for wall and decoration materials. The evaluation of protective coatings was performed with laser particle size analyzer, scanning probe microscope and a diffractometer. It showed that the average size of the particles forming the protective coating is in the range of 20–25 nm, the particles shape is spherical, the particles are elemental sulfur with orthorhombic structure of the crystal lattice. The processing of shell limestone with calcium polysulphide solution provides formation of coating based on nanosized sulfur on the surface of stone pores. The coating partially fills the pore space and, as it is hydrophobic, reduces the water absorption of the samples by a factor of 5–8, increases their average density by 22–27%, strength in 1,2–1,3 times, the softening factor by 6–19%, that makes possible to predict the increase of the durability of building materials based on shell limestone to 1

Distributed remote temperature monitoring system for INDUS-2 vacuum chambers

International Nuclear Information System (INIS)

Bhange, N.J.; Gothwal, P.; Fatnani, P.; Shukla, S.K.

2011-01-01

Indus-2, a 2.5 GeV Synchrotron Radiation Source (SRS) at Indore has a large vacuum system. The vacuum envelope of Indus-2 ring comprises of 16 dipole chambers as vital parts. Each chamber has 4 photon absorbers and three beam line ports blanked with end flanges. Temperature monitoring of critical vacuum components during operation of Indus-2 ring is an important requirement. The paper discusses a distributed, 160 channel remote temperature monitoring system developed and deployed for this purpose using microcontroller based, modular Temperature Monitoring Units (TMU). The cabling has been extensively minimized using RS485 system and keeping trip relay contacts of all units in series. For ensuring proper signal conditioning of thermocouple outputs (K-type) and successful operation over RS485 bus, many precautions were taken considering the close proximity to the storage ring. We also discuss the software for vacuum chamber temperature monitoring and safety system. The software developed using LabVIEW, has important features like modularity, client-server architecture, local and global database logging, alarms and trips, event and error logging, provision of various important configurations, communications handling etc. (author)

Contribution of apparently non-operating loadings to the buckling of thin shells and plates

International Nuclear Information System (INIS)

Delaigue, Didier.

1980-02-01

This work includes four parts: in the first part, the Kirchhoff-Love theory of thin shells is described, a theory taken up and developed by Koiter and whose modelling seems to meet the problems of engineers. The second part deals with the buckling of a thin plate subjected to a load along a part of its edge, of which a part or all is seemingly inoperative. In the third part the study is extended to shells of any shape subjected to a conservative loading of the ''dead-loading'' type along part of their edges. On the basis of the results of the previous study, a study is then made on the taking into account of any load applied to the edge of a thin shell. In the fourth part the previous results are applied to the study of the buckling of a thin shell with a circular base subjected along a part of its edge to a normal prestress and to twisting moments linear density [fr

Characterization of selective solar absorber under high vacuum.

Science.gov (United States)

Russo, Roberto; Monti, Matteo; di Giamberardino, Francesco; Palmieri, Vittorio G

2018-05-14

Total absorption and emission coefficients of selective solar absorbers are measured under high vacuum conditions from room temperature up to stagnation temperature. The sample under investigation is illuminated under vacuum @1000W/m 2 and the sample temperature is recorded during heat up, equilibrium and cool down. During stagnation, the absorber temperature exceeds 300°C without concentration. Data analysis allows evaluating the solar absorptance and thermal emittance at different temperatures. These in turn are useful to predict evacuated solar panel performances at operating conditions.

Vacuum pumping of tritium in fusion power reactors

International Nuclear Information System (INIS)

Coffin, D.O.; Walthers, C.R.

1979-01-01

Compound cryopumps of three different designs will be tested with deuterium-tritium (DT) mixtures under simulated fusion reactor conditions at the Tritium Systems Test Assembly (TSTA) now being constructed at the Los Alamos Scientific Laboratory (LASL). The first of these pumps is already in operation, and its preliminary performance is presented. The supporting vacuum facility necessary to regenerate these fusion facility cryopumps is also described. The next generation of fusion system vacuum pumps may include non-cryogenic or conventional-cryogenic hybrid systems, several of which are discussed

Insulation vacuum and beam vacuum overpressure release

CERN Document Server

Parma, V

2009-01-01

There is evidence that the incident of 19th September caused a high pressure build-up inside the cryostat insulation vacuum which the existing overpressure devices could not contain. As a result, high longitudinal forces acting on the insulation vacuum barriers developed and broke the floor and the floor fixations of the SSS with vacuum barriers. The consequent large longitudinal displacements of the SSS damaged chains of adjacent dipole cryo-magnets. Estimates of the helium mass flow and the pressure build- up experienced in the incident are presented together with the pressure build-up for an even more hazardous event, the Maximum Credible Incident (MCI). The strategy of limiting the maximum pressure by the installation of addition pressure relieve devices is presented and discussed. Both beam vacuum lines were ruptured during the incident in sector 3-4 giving rise to both mechanical damage and pollution of the system. The sequence, causes and effects of this damage will be briefly reviewed. We will then an...

Miniature piezo electric vacuum inlet valve

Science.gov (United States)

Keville, Robert F.; Dietrich, Daniel D.

1998-03-24

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

Unified description of pf-shell nuclei by the Monte Carlo shell model calculations

Energy Technology Data Exchange (ETDEWEB)

Mizusaki, Takahiro; Otsuka, Takaharu [Tokyo Univ. (Japan). Dept. of Physics; Honma, Michio

1998-03-01

The attempts to solve shell model by new methods are briefed. The shell model calculation by quantum Monte Carlo diagonalization which was proposed by the authors is a more practical method, and it became to be known that it can solve the problem with sufficiently good accuracy. As to the treatment of angular momentum, in the method of the authors, deformed Slater determinant is used as the basis, therefore, for making angular momentum into the peculiar state, projected operator is used. The space determined dynamically is treated mainly stochastically, and the energy of the multibody by the basis formed as the result is evaluated and selectively adopted. The symmetry is discussed, and the method of decomposing shell model space into dynamically determined space and the product of spin and isospin spaces was devised. The calculation processes are shown with the example of {sup 50}Mn nuclei. The calculation of the level structure of {sup 48}Cr with known exact energy can be done with the accuracy of peculiar absolute energy value within 200 keV. {sup 56}Ni nuclei are the self-conjugate nuclei of Z=N=28. The results of the shell model calculation of {sup 56}Ni nucleus structure by using the interactions of nuclear models are reported. (K.I.)

Ultra high vacuum systems for accelerators

International Nuclear Information System (INIS)

Loefgren, P.

2001-01-01

mbar, a combination of pumps is needed. At these low pressures there are, however, some pumps that are disqualified, such as pumps which not are bakable (some cryopumps) and pumps that are using organic fluids for pumping (diffusion pumps) or as lubricants (turbopumps). Instead a combination of pumps like sputter-ion pumps, getter pumps and cryo pumps are routinely used today at accelerator facilities to reach this extreme vacuum regime. In addition to pumping efficiency aspects like operation stability and costs have to be considered when choosing the appropriate pumps for the vacuum system. Even if quite a lot of work has been devoted to develop vacuum gauges for measuring pressures below 10 -11 mbar, only a few commercial gauges are available. It is of great importance that the gauge is capable of measuring without influencing the pressure to be measured, which often is the case. Most gauges used today in this pressure range are improved versions of the old Bayard-Alpert type developed in 1950. Using the storage ring, CRYRING, at the Manne Siegbahn Laboratory in Stockholm Sweden as an example it will be shown how it, with the right combination of vacuum pumps and materials, is possible to reach and keep the pressure below 10 -11 mbar over a long time during an experiment. Since a vacuum system of this type consists of more than just the chamber walls, pumps and gauges there are several other aspects that have to be considered in order to maintain low pressures. Detectors, electric wiring and all kinds of feedthroughs are just a few examples of weak links in the vacuum system. Other issues that will discussed are how to measure pressure when commercial gauges fail and how it is possible to use the background gas in a more constructive way instead of just considering it as a problem. (author)

Wireless Integrated Microelectronic Vacuum Sensor System

Science.gov (United States)

Krug, Eric; Philpot, Brian; Trott, Aaron; Lawrence, Shaun

2013-01-01

-gauge measurements automatically and wirelessly, in near-real time - using a low-maintenance, lowpower sensor mesh network. The WIMVSS operates by using a self-configuring mesh network of wireless sensor units. Mesh networking is a type of networking where each sensor or node can capture and disseminate its own data, but also serve as a relay to receive and transmit data from other sensors. Each sensor node can synchronize with adjacent sensors, and propagate data from one sensor to the next, until the destination is reached. In this case, the destination is a Network Interface Unit (NIU). The WIMVSS sensors are mounted on the existing vacuum gauges. Information gathered by the sensors is sent to the NIU. Because of the mesh networking, if a sensor cannot directly send the data to the NIU, it can be propagated through the network of sensors. The NIU requires antenna access to the sensor units, AC power, and an Ethernet connection. The NIU bridges the sensor network to a WIMVSS server via an Ethernet connection. The server is configured with a database, a Web server, and proprietary interface software that makes it possible for the vacuum measurements from vacuum jacketed fluid lines to be saved, retrieved, and then displayed from any Web-enabled PC that has access to the Internet. Authorized users can then simply access the data from any PC with Internet connection. Commands can also be sent directly from the Web interface for control and maintenance of the sensor network. The technology enabled by the WIMVSS decreases labor required for gathering vacuum measurements, increases access to vacuum data by making it available on any computer with access to the Internet, increases the frequency with which data points can be acquired for evaluating the system, and decreases the recurring cost of the sensors by using off-the-shelf components and integrating these with heritage vacuum gauges.

A vacuum disengager for tritium removal from HYLIFE-II Reactor Flibe

International Nuclear Information System (INIS)

Dolan, T.J.; Longhurst, G.R.; Garcia-Otero, E.

1992-01-01

We have designed a vacuum disengager system to remove tritium from the Flibe (Li 2 BeF 4 ) molten salt coolant of the HYLIFE-II fusion reactor. There is a two-stage vacuum disengager in each of three intermediate heat exchanger (IHX) loops. Each stage consists of a vacuum chamber 4 m in diameter and 7 m tall. As 0.2 mm diameter molten salt droplets fall vertically downward into the vacuum, most of the tritium diffuses out of the droplets and is pumped away. A fraction Φ ∼10 -5 of the 8.6 MCi/day tritium source (from breeding in the Flibe and from unburned fuel) remains in the Flibe as it leaves the vacuum disengagers, and about 21% of that permeates into the intermediate coolant loop, so about 20 Ci/day leak into the steam system. With Flibe primary coolant and a vacuum disengager, it appears that an intermediate coolant loop is not needed to prevent tritium from leaking into the steam system. An experiment is needed to demonstrate Flibe vacuum disengager operation

Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

Science.gov (United States)

Roy, Anindya; Bhole, R. B.; Nandy, Partha P.; Yadav, R. C.; Pal, Sarbajit; Roy, Amitava

2015-03-01

The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system.

Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

Energy Technology Data Exchange (ETDEWEB)

Roy, Anindya, E-mail: r-ani@vecc.gov.in; Bhole, R. B.; Nandy, Partha P.; Yadav, R. C.; Pal, Sarbajit; Roy, Amitava [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India)

2015-03-15

The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system.

Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

International Nuclear Information System (INIS)

Roy, Anindya; Bhole, R. B.; Nandy, Partha P.; Yadav, R. C.; Pal, Sarbajit; Roy, Amitava

2015-01-01

The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system

Dust processing device for inside of vacuum vessel of thermonuclear reactor

Energy Technology Data Exchange (ETDEWEB)

Okumura, Atsushi; Tsujimura, Seiichi; Takahashi, Kenji; Ueda, Yasutoshi; Kuwata, Masayasu; Onozuka, Masaki

1995-05-02

The device of the present invention can occasionally recover dusts in a vacuum vessel of a thermonuclear reactor. In addition, fine powdery dusts are never scattered to the vacuum vessel. Namely, a processing device main body comprises a locally sealed space in the vacuum vessel. A blow-up device blows up and floats dusts accumulated in the vacuum vessel to the processing device main body. A discharge plate electrically charges the floating dusts by discharge. An electrode collects the charged dusts. Collected dusts are recovered together with a pressurized gas through a dust recovering port to the outside of the processing device. With such a constitution, it is not necessary to release the vacuum vessel to the atmosphere and evacuate after the completion of the collection of the dusts on every time when the dusts are generated as in the prior art. It is no more necessary for an operator to enter into the vacuum vessel and recover the dusts. Since fine powdery dusts are never scattered in the vacuum vessel, no undesired effects are given to exhaustion facilities and instruments of the vacuum vessel. (I.S.).

Dust processing device for inside of vacuum vessel of thermonuclear reactor

International Nuclear Information System (INIS)

Okumura, Atsushi; Tsujimura, Seiichi; Takahashi, Kenji; Ueda, Yasutoshi; Kuwata, Masayasu; Onozuka, Masaki.

1995-01-01

The device of the present invention can occasionally recover dusts in a vacuum vessel of a thermonuclear reactor. In addition, fine powdery dusts are never scattered to the vacuum vessel. Namely, a processing device main body comprises a locally sealed space in the vacuum vessel. A blow-up device blows up and floats dusts accumulated in the vacuum vessel to the processing device main body. A discharge plate electrically charges the floating dusts by discharge. An electrode collects the charged dusts. Collected dusts are recovered together with a pressurized gas through a dust recovering port to the outside of the processing device. With such a constitution, it is not necessary to release the vacuum vessel to the atmosphere and evacuate after the completion of the collection of the dusts on every time when the dusts are generated as in the prior art. It is no more necessary for an operator to enter into the vacuum vessel and recover the dusts. Since fine powdery dusts are never scattered in the vacuum vessel, no undesired effects are given to exhaustion facilities and instruments of the vacuum vessel. (I.S.)

Optimization of Edwards vacuum coating unit model E12E for the production of thin films

International Nuclear Information System (INIS)

Ruiz P, H.S.

1995-01-01

This work is about an Edwards vacuum coating unit model E12E, it shows the principle of vacuum thermal evaporation, some observations in the operation of vacuum diffusion pumps, mechanical pumps, vacuum gauge, Penning and Pirani, and some equations of leak vacuum, after the modifications and additions of Edwards vacuum coating unit for optimization, the last part contains a concise introduction about thin films and one specific application, it also contains the recommendations and requirements to keep the system in good conditions. (Author)

Quantitative plasma spectroscopy in a resistive shell reversed-field pinch

International Nuclear Information System (INIS)

Hedqvist, Anders

1999-10-01

The subject addressed in this thesis is quantitative plasma spectroscopy. Measurements of electron temperature and impurity ion density, performed at EXTRAP-T2, are aimed to investigate the effects of operating a reversed- field pinch with a resistive shell and a graphite wall. The spectroscopic measurements are analyzed with a collisional-radiative model and a consistency check is performed for the measurements and the model itself. The resistive shell results in wall-locked modes, enhanced plasma-wall interaction and degraded confinement. Measurements of vacuum ultraviolet resonant transitions of carbon and oxygen show that the local heating of the wall, at the position of the locking, leads to influxes of hydrogen and impurities, resulting in a cold and resistive plasma. Effects on the local scale are also observed. Spatially-resolved measurements of line emission originating from charge exchange collisions are used to investigate the change in neutral hydrogen profile. Temporal correlations between soft x-ray emission and poloidal loop voltage at the position of the wall-locked modes are observed and in connection, a decrease in central electron temperature, indicating there is a direct energy loss channel between the center and the edge. The hydrogen recycling properties of the graphite wall are investigated in an isotope exchange experiment. The density of the hydrogen isotopes are measured from spectral line emission and compared with recycling models. In charge exchange collisions between fully stripped chlorine and thermal deuterium, observed in JET plasmas, only a single n-level is populated. This is different from most ions and may be used to test models for calculating charge exchange collision cross-sections

Quantitative plasma spectroscopy in a resistive shell reversed-field pinch

Energy Technology Data Exchange (ETDEWEB)

Hedqvist, Anders

1999-10-01

The subject addressed in this thesis is quantitative plasma spectroscopy. Measurements of electron temperature and impurity ion density, performed at EXTRAP-T2, are aimed to investigate the effects of operating a reversed- field pinch with a resistive shell and a graphite wall. The spectroscopic measurements are analyzed with a collisional-radiative model and a consistency check is performed for the measurements and the model itself. The resistive shell results in wall-locked modes, enhanced plasma-wall interaction and degraded confinement. Measurements of vacuum ultraviolet resonant transitions of carbon and oxygen show that the local heating of the wall, at the position of the locking, leads to influxes of hydrogen and impurities, resulting in a cold and resistive plasma. Effects on the local scale are also observed. Spatially-resolved measurements of line emission originating from charge exchange collisions are used to investigate the change in neutral hydrogen profile. Temporal correlations between soft x-ray emission and poloidal loop voltage at the position of the wall-locked modes are observed and in connection, a decrease in central electron temperature, indicating there is a direct energy loss channel between the center and the edge. The hydrogen recycling properties of the graphite wall are investigated in an isotope exchange experiment. The density of the hydrogen isotopes are measured from spectral line emission and compared with recycling models. In charge exchange collisions between fully stripped chlorine and thermal deuterium, observed in JET plasmas, only a single n-level is populated. This is different from most ions and may be used to test models for calculating charge exchange collision cross-sections.

Shell Venster

International Nuclear Information System (INIS)

De Wit, P.; Looijesteijn, B.; Regeer, B.; Stip, B.

1995-03-01

In the bi-monthly issues of 'Shell Venster' (window on Shell) attention is paid to the activities of the multinational petroleum company Shell Nederland and the Koninklijke/Shell Groep by means of non-specialist articles

The Insulation Vacuum Barrier for the Large Hadron Collider (LHC) Magnet Cryostats

CERN Document Server

Castoldi, M; Parma, Vittorio; Skoczen, Blazej; Trilhe, P

2000-01-01

The sectorisation of the insulation vacuum of the LHC magnet cryostats, housing the superconducting magnets, which operate in a 1.9 K superfluid helium bath, is achieved by means of vacuum barriers. Each vacuum barrier is a leak-tight austenitic stainless steel thin-wall structure, mainly composed of large diameter (between 0.6 m and 0.9 m) bellows and concentric corrugated cylinders. It is mounted in the Short Straight Section (SSS) [1], between the magnet helium enclosure and the vacuum vessel. This paper presents the design of the vacuum barrier, concentrating mostly on its expected thermal performance, to fulfil the tight LHC heat in-leak budgets. Pressure and leak test results, confirming the mechanical design of two prototypes manufactured in industry, and the preparation of one of these vacuum barriers for cryogenic testing in an SSS prototype, are also mentioned.

Thermogravimetric characterization and gasification of pecan nut shells.

Science.gov (United States)

Aldana, Hugo; Lozano, Francisco J; Acevedo, Joaquín; Mendoza, Alberto

2015-12-01

This study focuses on the evaluation of pecan nut shells as an alternative source of energy through pyrolysis and gasification. The physicochemical characteristics of the selected biomass that can influence the process efficiency, consumption rates, and the product yield, as well as create operational problems, were determined. In addition, the thermal decomposition kinetics necessary for prediction of consumption rates and yields were determined. Finally, the performance of a downdraft gasifier fed with pecan nut shells was analyzed in terms of process efficiency and exit gas characteristics. It was found that the pyrolytic decomposition of the nut shells can be modeled adequately using a single equation considering two independent parallel reactions. The performance of the gasification process can be influenced by the particle size and air flow rate, requiring a proper combination of these parameters for reliable operation and production of a valuable syngas. Copyright © 2015 Elsevier Ltd. All rights reserved.

Using vacuum in the treatment of surgical wounds complications

Directory of Open Access Journals (Sweden)

Drašković Miroljub

2011-01-01

Full Text Available Background/Aim. Using vacuum in medicine has been known from long ago, however, it has not been used for the treatment of wounds. The first experiments in this field were performed by Wagner Fleischmann, University of Ulm, Ulm, West Germany, in 1993. The aim of this study was to present our clinical experience with the treatment of surgical wounds complications in vascular patients by the use of controled vacuum. Method. In a period October 2006 - December 2009 a total of 18 patients with infection and surgical wound dehiscence were treated by the use of vacuum. Vacuum was applied to wounds by placing a polyurethane sponge on them and by fixing a polyurethane foil and a sponge to the surrounding healthy skin so to completely airtight wounds. Over a foil vacuum of - 150 mmHg was applied for a 5-day period, and on the day 6 a foil and a sponge were removed. Results. In all the 18 wounds treated by the use of vacuum secondary wound closing was achieved with no complications and with a significantly shortened time period treatment. Wound infections were healed using this method and only in 2 patients antibiotics were used at the same time. Conclusion. The use of vacuum in the treatment of operative wounds complications is an easy and reliable method contributing significantly to wounds better healing.

Snap-Through Buckling Problem of Spherical Shell Structure

Directory of Open Access Journals (Sweden)

Sumirin Sumirin

2014-12-01

Full Text Available This paper presents results of a numerical study on the nonlinear behavior of shells undergoing snap-through instability. This research investigates the problem of snap-through buckling of spherical shells applying nonlinear finite element analysis utilizing ANSYS Program. The shell structure was modeled by axisymmetric thin shell of finite elements. Shells undergoing snap-through buckling meet with significant geometric change of their physical configuration, i.e. enduring large deflections during their deformation process. Therefore snap-through buckling of shells basically is a nonlinear problem. Nonlinear numerical operations need to be applied in their analysis. The problem was solved by a scheme of incremental iterative procedures applying Newton-Raphson method in combination with the known line search as well as the arc- length methods. The effects of thickness and depth variation of the shell is taken care of by considering their geometrical parameter l. The results of this study reveal that spherical shell structures subjected to pressure loading experience snap-through instability for values of l≥2.15. A form of ‘turn-back’ of the load-displacement curve took place at load levels prior to the achievement of the critical point. This phenomenon was observed for values of l=5.0 to l=7.0.

Large vacuum system for experiences in magnetic confined plasmas

International Nuclear Information System (INIS)

Honda, R.Y.; Kayama, M.E.; Boeckelmann, H.K.; Aihara, S.

1984-01-01

It is presented the operation method of a theta-pinch system capable of generating and confine plasmas with high densities and temperatures. Some characteristics of Tupa theta-pinch, which is operating at UNICAMP, emphasizing the cleaning mode of the vacuum chamber, are also presented. (M.C.K.) [pt

Combustion of palm kernel shell in a fluidized bed: Optimization of biomass particle size and operating conditions

International Nuclear Information System (INIS)

Ninduangdee, Pichet; Kuprianov, Vladimir I.

2014-01-01

Highlights: • Safe burning of palm kernel shell is achievable in a FBC using alumina as the bed material. • Thermogravimetric analysis of the shell with different particle sizes is performed. • Optimal values of the shell particle size and excess air lead to the minimum emission costs. • Combustion efficiency of 99.4–99.7% is achievable when operated under optimal conditions. • CO and NO emissions of the FBC are at levels substantially below national emission limits. - Abstract: This work presents a study on the combustion of palm kernel shell (PKS) in a conical fluidized-bed combustor (FBC) using alumina sand as the bed material to prevent bed agglomeration. Prior to combustion experiments, a thermogravimetric analysis was performed in nitrogen and dry air to investigate the effects of biomass particle size on thermal and combustion reactivity of PKS. During the combustion tests, the biomass with different mean particle sizes (1.5 mm, 4.5 mm, 7.5 mm, and 10.5 mm) was burned at a 45 kg/h feed rate, while excess air was varied from 20% to 80%. Temperature and gas concentrations (O 2 , CO, C x H y as CH 4 , and NO) were recorded along the axial direction in the reactor as well as at stack. The experimental results indicated that the biomass particle size and excess air had substantial effects on the behavior of gaseous pollutants (CO, C x H y , and NO) in different regions inside the reactor, as well as on combustion efficiency and emissions of the conical FBC. The CO and C x H y emissions can be effectively controlled by decreasing the feedstock particle size and/or increasing excess air, whereas the NO emission can be mitigated using coarser biomass particles and/or lower excess air. A cost-based approach was applied to determine the optimal values of biomass particle size and excess air, ensuring minimum emission costs of burning the biomass in the proposed combustor. From the optimization analysis, the best combustion and emission performance of the

Cask for concrete shells transportation

International Nuclear Information System (INIS)

Labergri, F.

2001-01-01

Nowadays, nuclear plant radioactive waste are conditioned in situ into concrete shells. Most of them enter in the industrial waste category defined by the regulations of radioactive material transportation. However, the content of a few ones exceeds the limits set for low specific activity substances. Thus, these shells must be transported into type B packagings. To this end, Robatel has undertaken, for EDF (Electricite de France), the development of a container, named ROBATEL TM R68, for further licensing. The particularity of this packaging is that the lid must have a wide opening to allow the usual handling operations of the concrete shells. This leads to a non-conventional conception, and makes the package more vulnerable to drop test solicitations. In order to define a minimal drop test program on a reduced scale model, we use a simple method to find the most damageable drop angle. (author)

Cold Vacuum Drying (CVD) Facility Technical Safety Requirements

International Nuclear Information System (INIS)

KRAHN, D.E.

2000-01-01

The Technical Safety Requirements (TSRs) for the Cold Vacuum Drying Facility define acceptable conditions, safe boundaries, bases thereof, and management or administrative controls required to ensure safe operation during receipt of multi-canister overpacks (MCOs) containing spent nuclear fuel. removal of free water from the MCOs using the cold vacuum drying process, and inerting and testing of the MCOs before transport to the Canister Storage Building. Controls required for public safety, significant defense in depth, significant worker safety, and for maintaining radiological and toxicological consequences below risk evaluation guidelines are included

Multistage charged particle accelerator, with high-vacuum insulation

International Nuclear Information System (INIS)

Holl, P.

1976-01-01

A multistage charged-particle accelerator for operating with accelerating voltages higher than 150 kV is described. The device consists essentially of a high-voltage insulator, a source for producing charged particles, a Wehnelt cylinder, an anode, and a post-accelerating tube containing stack-wise positioned post-accelerating electrodes. A high vacuum is used for insulating the parts carrying the high voltages, and at least one cylindrical screen surrounding these parts is interposed between them and the vacuum vessel, which can itself also function as a cylindrical screen

A remote joint system for large vacuum ducts

International Nuclear Information System (INIS)

Hagmann, D.B.; Coughlan, J.B.

1983-01-01

A large remote vacuum duct joining system has been developed for fusion machines that uses several two-jaw screwdriven clamps. The preferred location for clamp installation is inside the vacuum duct where access space is available for the actuating device. It also decreases space needed for handling operations exterior to the duct. The clamp system is unique in that it is low cost, applies force directly over the seal, permits leak testing to the seal annulus, is highly reliable, can be remotely replaced, and is usable on a variety of other applications

An evaluation of Shell's approach to conflict resolution in the Niger ...

African Journals Online (AJOL)

of Shell's successes and failures as well as of Nigeria's power relations and institutional architecture ..... there is a gross deficiency of transparent and credible public participation in ..... Shell's social licence to operate: A case study of Ogoni. In:.

Manufacturing progress on the first sector and lower ports for ITER vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Ahn, H.J., E-mail: hjahn@nfri.re.kr [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Kim, H.S.; Kim, G.H.; Park, C.K.; Hong, G.H.; Jin, S.W.; Lee, H.G.; Jung, K.J. [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Lee, J.S.; Kim, T.S.; Won, J.G.; Roh, B.R.; Park, K.H. [Hyundai Heavy Industries Co. Ltd., Ulsan 682-792 (Korea, Republic of); Sa, J.W.; Choi, C.H.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance (France)

2016-11-01

Highlights: • All manufacturing drawings of the first sector of VV have been completed. • Full scale mock-ups have been constructed to verify fabrication procedure. • Qualifications for welding and forming are done and for NDE are ongoing. • Manufacturing progress is around 40% for the sector and LPSE up to the end of 2015. - Abstract: Manufacturing design of Korean sectors and ports for the ITER Vacuum Vessel (VV) has been developed to comply with the tight tolerance and severe inspection requirements. The first VV sector and lower ports are being fabricated slowly under strict regulations after verification using several real scale mock-ups and qualifications for welding, forming and NDE. During three years after start of fabrication, manufacturing progress on four poloidal segments of the first sector is that (1) all inner shells were welded, (2) forgings for complicate components have been machined, (3) port stubs and poloidal T-ribs were assembled, and (4) machined components are welded on the inner shells by narrow-gap TIG welding and electron beam welding. The progress of lower ports is that (1) inner shells of stub extensions were bent and treated with heat, (2) T-ribs were fabricated and examined by qualified phased array UT, (3) supporting pads and gussets have been machined, and (4) inner shells are assembled with T-ribs and machined forgings. The progress rate of manufacturing is around 40% up to the end of 2015 for the first sector and lower port stub extensions.

Vacuum vessel for the tandem Mirror Fusion Test Facility

International Nuclear Information System (INIS)

Gerich, J.W.

1986-01-01

In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10 -8 torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200-m 3 internal volume) has been fabricated and erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system

Importance-truncated shell model for multi-shell valence spaces

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Christina; Vobig, Klaus; Roth, Robert [Institut fuer Kernphysik, TU Darmstadt (Germany)

2016-07-01

The valence-space shell model is one of the work horses in nuclear structure theory. In traditional applications, shell-model calculations are carried out using effective interactions constructed in a phenomenological framework for rather small valence spaces, typically spanned by one major shell. We improve on this traditional approach addressing two main aspects. First, we use new effective interactions derived in an ab initio approach and, thus, establish a connection to the underlying nuclear interaction providing access to single- and multi-shell valence spaces. Second, we extend the shell model to larger valence spaces by applying an importance-truncation scheme based on a perturbative importance measure. In this way, we reduce the model space to the relevant basis states for the description of a few target eigenstates and solve the eigenvalue problem in this physics-driven truncated model space. In particular multi-shell valence spaces are not tractable otherwise. We combine the importance-truncated shell model with refined extrapolation schemes to approximately recover the exact result. We present first results obtained in the importance-truncated shell model with the newly derived ab initio effective interactions for multi-shell valence spaces, e.g., the sdpf shell.

On the atomic shell structure calculation (1)

International Nuclear Information System (INIS)

Choe Sun Chol

1986-01-01

We have considered the problem of atomic shell structure calculation using operator technique. We introduce reduced matrix elements of annihilation operators according to eg. (4). The normalized basis function is denoted as || ...>. The reduced matrix elements of the pair annihilation operators are expressed throw one-electron matrix elements. Some numerical results are represented and the problem of sign assignment is discussed. (author)

Vacuum arc ion charge state distributions

International Nuclear Information System (INIS)

Brown, I.G.; Godechot, X.

1990-06-01

We have measured vacuum arc ion charge state spectra for a wide range of metallic cathode materials. The charge state distributions were measured using a time-of-flight diagnostic to monitor the energetic ion beam produced by a metal vapor vacuum arc ion source. We have obtained data for 48 metallic cathode elements: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U. The arc was operated in a pulsed mode with pulse length 0.25 msec; arc current was 100 A throughout. This array of elements extends and completes previous work by us. In this paper the measured distributions are cataloged and compared with our earlier results and with those of other workers. We also make some observations about the performance of the various elements as suitable vacuum arc cathode materials

Vacuum arc ion charge-state distributions

International Nuclear Information System (INIS)

Brown, I.G.; Godechot, X.

1991-01-01

The authors have measured vacuum arc ion charge-state spectra for a wide range of metallic cathode materials. The charge-state distributions were measured using a time-of-flight diagnostic to monitor the energetic ion beam produced by a metal vapor vacuum arc ion source. They have obtained data for 48 metallic cathode elements: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th, and U. The arc was operated in a pulsed mode with pulse length 0.25 ms; arc current was 100 A throughout. This array of elements extends and completes previous work by the authors. In this paper the measured distributions are cataloged and compared with their earlier results and those of other workers. They also make some observations about the performance of the various elements as suitable vacuum arc cathode materials

Beam Dump TIDV #1 - Vacuum Failure of 17 Oct. 97

CERN Document Server

Ross, M; CERN. Geneva. SPS and LEP Division

1997-01-01

A vacuum leak on the internal beam dump TIDV precipitated its replacement in the LSS1 on Monday the 20th of October 1997, the SPS consequently being shut down for three days. The dump had fulfilled its design function since it was installed in the SPS at the beginning of 1988. Prior to the intervention, the Vacuum Group LHC/VAC carried out a number of leak tests, which led to the decision being taken to replace the dump. After the successful intervention, normal machine operation was resumed. Out-gassing of the ten-year-old replacement was initially high, but vacuum pressure is slowly descending to the SPS standard level.

Technological plasma source equipped with combined system of vacuum-arc discharge initiation

International Nuclear Information System (INIS)

Sysoev, Yu.O.

2013-01-01

The construction and the operation principle of erosion plasma source with a three-stage system of vacuum-arc discharge excitation is described. As first two step was used the modified contactless start system with plasma injector, which was widely used in standard plasma sources of the ''Bulat'' systems. The operation principle of the third stage was based on the transition of glow discharge to arc discharge. Coordinated operation of three stages during various stages of coating deposition provided significant increasing of service life and reliability of the system of vacuum-arc discharge initiation and extended the functionality of the plasma source

Noncommutative geometry and the standard model vacuum

International Nuclear Information System (INIS)

Barrett, John W.; Dawe Martins, Rachel A.

2006-01-01

The space of Dirac operators for the Connes-Chamseddine spectral action for the standard model of particle physics coupled to gravity is studied. The model is extended by including right-handed neutrino states, and the S 0 -reality axiom is not assumed. The possibility of allowing more general fluctuations than the inner fluctuations of the vacuum is proposed. The maximal case of all possible fluctuations is studied by considering the equations of motion for the vacuum. While there are interesting nontrivial vacua with Majorana-type mass terms for the leptons, the conclusion is that the equations are too restrictive to allow solutions with the standard model mass matrix

Vacuum mechatronics first international workshop

Energy Technology Data Exchange (ETDEWEB)

Belinski, S.E.; Shirazi, M.; Hackwood, S.; Beni, G. (eds.) (California Univ., Santa Barbara, CA (USA))

1989-01-01

This report contains papers on the following topics: proposed epitaxial thin film growth in the ultra-vacuum of space; particle monitoring and control in vacuum processing equipment; electrostatic dust collector for use in vacuum systems; materials evaluation of an electrically noisy vacuum slip ring assembly; an overview of lubrication and associated materials for vacuum service; the usage of lubricants in a vacuum environment; guidelines and practical applications for lubrication in vacuum; recent development in leak detector and calibrator designs; the durability of ballscrews for ultrahigh vacuum; vacuum-compatible robot for self-contained manufacturing systems; the design, fabrication, and assembly of an advanced vacuum robotics system for space payload calibration; design criteria for mechanisms used in space; and concepts and requirements for semiconductor multiprocess integration in vacuum. These papers are indexed separately elsewhere.

Definition and means of maintaining the process vacuum liquid detection interlock systems portion of the PFP safety envelope

International Nuclear Information System (INIS)

THOMAS, R.J.

1999-01-01

The Process Vacuum Liquid Detection interlock systems prevent intrusion of process liquids into the HEPA filters downstream of demisters No.6 and No.7 during Process Vacuum System operation. This prevents liquid intrusion into the filters, which could cause a criticality. The Safety Envelope (SE) includes the equipment, which detects the presence of liquids in the vacuum headers; isolates the filters; shuts down the vacuum pumps; and alarms the condition. This report identifies the equipment in the SE operating, maintenance, and surveillance procedures needed to maintain the SE equipment; and rationale for exclusion of some equipment and testing from the SE

A safety equipment list for rotary mode core sampling systems operation in single shell flammable gas tanks

International Nuclear Information System (INIS)

SMALLEY, J.L.

1999-01-01

This document identifies all interim safety equipment to be used for rotary mode core sampling of single-shell flammable gas tanks utilizing Rotary Mode Core Sampling systems (RMCS). This document provides the safety equipment for RMCS trucks HO-68K-4600, HO-68K-4647, trucks three and four respectively, and associated equipment. It is not intended to replace or supersede WHC-SD-WM-SEL-023, (Kelly 1991), or WHC-SD-WM-SEL-032, (Corbett 1994), which classifies 80-68K-4344 and HO-68K-4345 respectively. The term ''safety equipment'' refers to safety class (SC) and safety significant (SS) equipment, where equipment refers to structures, systems and components (SSC's). The identification of safety equipment in this document is based on the credited design safety features and analysis contained in the Authorization Basis (AB) for rotary mode core sampling operations in single-shell flammable gas tanks. This is an interim safety classification since the AB is interim. This document will be updated to reflect the final RMCS equipment safety classification designations upon completion of a final AB which will be implemented with the release of the Final Safety Analysis Report (FSAR)

REQUIREMENTS AND GUIDELINES FOR NSLS EXPERIMENTAL BEAM LINE VACUUM SYSTEMS-REVISION B

International Nuclear Information System (INIS)

FOERSTER, C.

1999-01-01

Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas after a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, more energetic photons of the x-ray ring, beryllium windows are used at various beam line locations so that the monochromator, mirror box or sample chamber may be used in a helium atmosphere or rough vacuum. The window separates ring vacuum from the environment of the downstream beam line components. The stored beam lifetime in the storage rings and the maintenance of desirable reflection properties of optical surfaces depend upon hydrocarbon-free, ultra-high vacuum systems. Storage ring vacuum systems will operate at pressures of ∼ 1 x 10 -10 Torr without beam and ∼ 1 x 10 -9 Torr with beam. Systems are free of hydrocarbons in the sense that no pumps, valves, etc. containing organics are used. Components are all-metal, chemically cleaned and bakeable. To the extent that beam lines share a common vacuum with the storage ring, the same criteria will hold for beam line components. The design philosophy for NSLS beam lines is to use all-metal, hydrocarbon-free front end components and recommend that experimenters use this approach for common vacuum hardware downstream of front ends. O-ring-sealed valves, if used, are not

Solar radiation for sea-water desalination and electric power generation via vacuum solar collectors

International Nuclear Information System (INIS)

Mottinelli, L.; Reali, M.; El-Nashar, A.M.; Giusiano, F.; Vigotti, R.

1996-01-01

The present report concerns the energetic potential of vacuum solar which are rather versatile and efficient devices for converting solar energy into thermal energy. Two main energetic applications have been analysed: the first one for a solar sea water desalination plant which has been operated in Abu Dhabi for the past ten years, the other for a conceptual solar thermoelectric-power plant having a fair thermodynamic efficiency (15-20%). A simple technology for the manufacture of vacuum solar collectors in a standard mechanical shop is being developed in collaboration between ENEL Sp A (DSR-CRIS, Milano) and WED (Abu Dhabi). Such technology should have an important economy-saving potential per se and would also make repair and substitution operations simple enough for the actual operators of the vacuum solar collector system without any need of external assistance. The technic-operative-economical features of the Abu Dhabi solar desalination plant suggest that the use novel simplified vacuum solar collectors could have a considerable technic economical potential. The analysis of the conceptual solar thermo-electric-power plant focuses on its general layout and singles out key technological issues which ought to be addressed in an overall feasibility study. 5 figs., 3 tabs

A highly miniaturized vacuum package for a trapped ion atomic clock

Energy Technology Data Exchange (ETDEWEB)

Schwindt, Peter D. D., E-mail: pschwin@sandia.gov; Jau, Yuan-Yu; Partner, Heather; Casias, Adrian; Wagner, Adrian R.; Moorman, Matthew; Manginell, Ronald P. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Kellogg, James R.; Prestage, John D. [Jet Propulsion Laboratory, Pasadena, California 91109 (United States)

2016-05-15

We report on the development of a highly miniaturized vacuum package for use in an atomic clock utilizing trapped ytterbium-171 ions. The vacuum package is approximately 1 cm{sup 3} in size and contains a linear quadrupole RF Paul ion trap, miniature neutral Yb sources, and a non-evaporable getter pump. We describe the fabrication process for making the Yb sources and assembling the vacuum package. To prepare the vacuum package for ion trapping, it was evacuated, baked at a high temperature, and then back filled with a helium buffer gas. Once appropriate vacuum conditions were achieved in the package, it was sealed with a copper pinch-off and was subsequently pumped only by the non-evaporable getter. We demonstrated ion trapping in this vacuum package and the operation of an atomic clock, stabilizing a local oscillator to the 12.6 GHz hyperfine transition of {sup 171}Y b{sup +}. The fractional frequency stability of the clock was measured to be 2 × 10{sup −11}/τ{sup 1/2}.

Effects of multiple resistive shells and transient electromagnetic torque on the dynamics of mode locking in reversed field pinch plasmas

International Nuclear Information System (INIS)

Guo, S.C.; Chu, M.S.

2002-01-01

The effects of multiple resistive shells and transient electromagnetic torque on the dynamics of mode locking in the reversed field pinch (RFP) plasmas are studied. Most RFP machines are equipped with one or more metal shells outside of the vacuum vessel. These shells have finite resistivities. The eddy currents induced in each of the shells contribute to the braking electromagnetic (EM) torque which slows down the plasma rotation. In this work we study the electromagnetic torque acting on the plasma (tearing) modes produced by a system of resistive shells. These shells may consist of several nested thin shells or several thin shells enclosed within a thick shell. The dynamics of the plasma mode is investigated by balancing the EM torque from the resistive shells with the plasma viscous torque. Both the steady state theory and the time-dependent theory are developed. The steady state theory is shown to provide an accurate account of the resultant EM torque if (dω/dt)ω -2 <<1 and the time scale of interest is much longer than the response (L/R) time of the shell. Otherwise, the transient theory should be adopted. As applications, the steady state theory is used to evaluate the changes of the EM torque response from the resistive shells in two variants of two RFP machines: (1) modification from Reversed Field Experiment (RFX) [Gnesotto et al., Fusion Eng. Des. 25, 335 (1995)] to the modified RFX: both of them are equipped with one thin shell plus one thick shell; (2) modification from Extrap T2 to Extrap T2R [Brunsell et al., Plasma Phys. Controlled Fusion 43, 1457 (2001)]: both of them are equipped with two thin shells. The transient theory has been applied numerically to study the time evolution of the EM torque during the unlocking of a locked tearing mode in the modified RFX

Magnetically induced vacuum decay

International Nuclear Information System (INIS)

Xue Shesheng

2003-01-01

We study the fermionic vacuum energy of vacua with and without application of an external magnetic field. The energetic difference of two vacua leads to the vacuum decaying and the vacuum energy being released. In the context of quantum field theories, we discuss why and how the vacuum energy can be released by spontaneous photon emission and/or paramagnetically screening the external magnetic field. In addition, we quantitatively compute the vacuum energy released, the paramagnetic screening effect, and the rate and spectrum of spontaneous photon emission. The possibilities of experimentally detecting such an effect of vacuum-energy release and that this effect accounts for the anomalous x-ray pulsar are discussed

PC driven integrated vacuum system

International Nuclear Information System (INIS)

Curuia, Marian; Culcer, Mihai; Brandea, Iulian; Anghel, Mihai

2001-01-01

The monitoring of industrial plants by virtual instrumentation represents the most modern trend in the domain of electronic equipment. The integrated vacuum system presented here has several facilities, including the automated data storing of measurement results on hard disk and providing warning messages for operators when the measured parameters are lower or higher upper than the fixed values. The system can also work stand-alone, receiving the commands from the keyboards placed on his front panel but, when it is included in a automation complex system, a remote control from PC is necessary . Both parts of the system, power supply unit for turbo-molecular pump and the vacuum gage, are controlled by an 80C31 microcontroller. Because this microcontroller has a built-in circuitry for a serial communication, we established a serial communication between the PC and the power supply unit for turbo-molecular pump and the vacuum gage, according to the RS-232 hardware standard. As software, after careful evaluation of several options, we chose to develop a hybrid software packing using two different software development tools: LabVIEW, and assembly language. We chose LabVIEW because it is dedicated to data acquisition and communications, containing libraries for data collection, analysis, display and storage. (authors)

Electroweak vacuum instability and renormalized Higgs field vacuum fluctuations in the inflationary universe

Energy Technology Data Exchange (ETDEWEB)

Kohri, Kazunori [Institute of Particle and Nuclear Studies, KEK, 1-1 Oho, Tsukuba 305-0801 (Japan); Matsui, Hiroki, E-mail: kohri@post.kek.jp, E-mail: matshiro@post.kek.jp [The Graduate University for Advanced Studies (SOKENDAI), 1-1 Oho, Tsukuba 305-0801 (Japan)

2017-08-01

In this work, we investigated the electroweak vacuum instability during or after inflation. In the inflationary Universe, i.e., de Sitter space, the vacuum field fluctuations < δ φ {sup 2} > enlarge in proportion to the Hubble scale H {sup 2}. Therefore, the large inflationary vacuum fluctuations of the Higgs field < δ φ {sup 2} > are potentially catastrophic to trigger the vacuum transition to the negative-energy Planck-scale vacuum state and cause an immediate collapse of the Universe. However, the vacuum field fluctuations < δ φ {sup 2} >, i.e., the vacuum expectation values have an ultraviolet divergence, and therefore a renormalization is necessary to estimate the physical effects of the vacuum transition. Thus, in this paper, we revisit the electroweak vacuum instability from the perspective of quantum field theory (QFT) in curved space-time, and discuss the dynamical behavior of the homogeneous Higgs field φ determined by the effective potential V {sub eff}( φ ) in curved space-time and the renormalized vacuum fluctuations < δ φ {sup 2} >{sub ren} via adiabatic regularization and point-splitting regularization. We simply suppose that the Higgs field only couples the gravity via the non-minimal Higgs-gravity coupling ξ(μ). In this scenario, the electroweak vacuum stability is inevitably threatened by the dynamical behavior of the homogeneous Higgs field φ, or the formations of AdS domains or bubbles unless the Hubble scale is small enough H < Λ {sub I} .

Optical properties of core-shell and multi-shell nanorods

Science.gov (United States)

Mokkath, Junais Habeeb; Shehata, Nader

2018-05-01

We report a first-principles time dependent density functional theory study of the optical response modulations in bimetallic core-shell (Na@Al and Al@Na) and multi-shell (Al@Na@Al@Na and Na@Al@Na@Al: concentric shells of Al and Na alternate) nanorods. All of the core-shell and multi-shell configurations display highly enhanced absorption intensity with respect to the pure Al and Na nanorods, showing sensitivity to both composition and chemical ordering. Remarkably large spectral intensity enhancements were found in a couple of core-shell configurations, indicative that optical response averaging based on the individual components can not be considered as true as always in the case of bimetallic core-shell nanorods. We believe that our theoretical results would be useful in promising applications depending on Aluminum-based plasmonic materials such as solar cells and sensors.

Vacuum extraction

DEFF Research Database (Denmark)

Maagaard, Mathilde; Oestergaard, Jeanett; Johansen, Marianne

2012-01-01

Objectives. To develop and validate an Objective Structured Assessment of Technical Skills (OSATS) scale for vacuum extraction. Design. Two-part study design: Primarily, development of a procedure-specific checklist for vacuum extraction. Hereafter, validation of the developed OSATS scale for vac...

Theoretical spectroscopy and the fp shell

International Nuclear Information System (INIS)

Poves, A.; Zuker, A.

1980-01-01

The recently developed quasiconfiguration method is applied to fp shell nuclei. Second order degenerate perturbation theory is shown to be sufficient to produce, for low lying states, the same results as large diagonalizations in the f(7/2)p(3/2)p(1/2)f(5/2)sup(n) full space. due to the operation of linked cluster mechanisms. Realistic interactions with minimal monopole changes are shown to be successful in reproducing spectra, binding energies, quadrupole moments and transition rates. Large shell model spaces are seen to exhibit typical many body behaviour. Quasiconfigurations allow insight into the underlying coupling schemes

Load responsive multilayer insulation performance testing

Energy Technology Data Exchange (ETDEWEB)

Dye, S.; Kopelove, A. [Quest Thermal Group, 6452 Fig Street Suite A, Arvada, CO 80004 (United States); Mills, G. L. [Ball Aerospace and Technologies Corp, 1600 Commerce Street, Boulder, CO 80301 (United States)

2014-01-29

Cryogenic insulation designed to operate at various pressures from one atmosphere to vacuum, with high thermal performance and light weight, is needed for cryogenically fueled space launch vehicles and aircraft. Multilayer insulation (MLI) performs well in a high vacuum, but the required vacuum shell for use in the atmosphere is heavy. Spray-on foam insulation (SOFI) is often used in these systems because of its light weight, but can have a higher heat flux than desired. We report on the continued development of Load Responsive Multilayer Insulation (LRMLI), an advanced thermal insulation system that uses dynamic beam discrete spacers that provide high thermal performance both in atmosphere and vacuum. LRMLI consists of layers of thermal radiation barriers separated and supported by micromolded polymer spacers. The spacers have low thermal conductance, and self-support a thin, lightweight vacuum shell that provides internal high vacuum in the insulation. The dynamic load responsive spacers compress to support the external load of a vacuum shell in one atmosphere, and decompress under reduced atmospheric pressure for lower heat leak. Structural load testing was performed on the spacers with various configurations. LRMLI was installed on a 400 liter tank and boil off testing with liquid nitrogen performed at various chamber pressures from one atmosphere to high vacuum. Testing was also performed with an MLI blanket on the outside of the LRMLI.

Load responsive multilayer insulation performance testing

International Nuclear Information System (INIS)

Dye, S.; Kopelove, A.; Mills, G. L.

2014-01-01

Cryogenic insulation designed to operate at various pressures from one atmosphere to vacuum, with high thermal performance and light weight, is needed for cryogenically fueled space launch vehicles and aircraft. Multilayer insulation (MLI) performs well in a high vacuum, but the required vacuum shell for use in the atmosphere is heavy. Spray-on foam insulation (SOFI) is often used in these systems because of its light weight, but can have a higher heat flux than desired. We report on the continued development of Load Responsive Multilayer Insulation (LRMLI), an advanced thermal insulation system that uses dynamic beam discrete spacers that provide high thermal performance both in atmosphere and vacuum. LRMLI consists of layers of thermal radiation barriers separated and supported by micromolded polymer spacers. The spacers have low thermal conductance, and self-support a thin, lightweight vacuum shell that provides internal high vacuum in the insulation. The dynamic load responsive spacers compress to support the external load of a vacuum shell in one atmosphere, and decompress under reduced atmospheric pressure for lower heat leak. Structural load testing was performed on the spacers with various configurations. LRMLI was installed on a 400 liter tank and boil off testing with liquid nitrogen performed at various chamber pressures from one atmosphere to high vacuum. Testing was also performed with an MLI blanket on the outside of the LRMLI

The vacuum system for technological unit development and design

Science.gov (United States)

Zhukeshov, A. M.; Gabdullina, A. T.; Amrenova, A. U.; Giniyatova, Sh G.; Kaibar, A.; Sundetov, A.; Fermakhan, K.

2015-11-01

The paper shows results of development of plasma technological unit on the basis of accelerator of vacuum arc and automated system. During the previous years, the authors investigated the operation of pulsed plasma accelerator and developed unique technologies for hardening of materials. Principles of plasma formation in pulsed plasma accelerator were put into basis of the developed unit. Operation of the pulsed arc accelerator was investigated at different parameters of the charge. The developed vacuum system is designed for production of hi-tech plasma units in high technologies in fields of nanomaterials, mechanical and power engineering and production with high added value. Unlike integrated solutions, the system is a module one to allow its low cost, high reliability and simple maintenance. The problems of use of robots are discussed to modernize the technological process.

The vacuum system for technological unit development and design

International Nuclear Information System (INIS)

Zhukeshov, A M; Gabdullina, A T; Amrenova, A U; Giniyatova, Sh G; Kaibar, A; Sundetov, A; Fermakhan, K

2015-01-01

The paper shows results of development of plasma technological unit on the basis of accelerator of vacuum arc and automated system. During the previous years, the authors investigated the operation of pulsed plasma accelerator and developed unique technologies for hardening of materials. Principles of plasma formation in pulsed plasma accelerator were put into basis of the developed unit. Operation of the pulsed arc accelerator was investigated at different parameters of the charge. The developed vacuum system is designed for production of hi-tech plasma units in high technologies in fields of nanomaterials, mechanical and power engineering and production with high added value. Unlike integrated solutions, the system is a module one to allow its low cost, high reliability and simple maintenance. The problems of use of robots are discussed to modernize the technological process. (paper)

Vacuum source-field correlations and advanced waves in quantum optics

Directory of Open Access Journals (Sweden)

Adam Stokes

2018-01-01

Full Text Available The solution to the wave equation as a Cauchy problem with prescribed fields at an initial time $t=0$ is purely retarded. Similarly, in the quantum theory of radiation the specification of Heisenberg picture photon annihilation and creation operators at time $t \\gt 0$ in terms of operators at $t=0$ automatically yields purely retarded source-fields. However, we show that two-time quantum correlations between the retarded source-fields of a stationary dipole and the quantum vacuum-field possess advanced wave-like contributions. Despite their advanced nature, these correlations are perfectly consistent with Einstein causality. It is shown that while they do not significantly contribute to photo-detection amplitudes in the vacuum state, they do effect the statistics of measurements involving the radiative force experienced by a point charge in the field of the dipole. Specifically, the dispersion in the charge's momentum is found to increase with time. This entails the possibility of obtaining direct experimental evidence for the existence of advanced waves in physical reality, and provides yet another signature of the quantum nature of the vacuum.

Space Suit Portable Life Support System (PLSS) 2.0 Unmanned Vacuum Environment Testing

Science.gov (United States)

Watts, Carly; Vogel, Matthew

2016-01-01

For the first time in more than 30 years, an advanced space suit Portable Life Support System (PLSS) design was operated inside a vacuum chamber representative of the flight operating environment. The test article, PLSS 2.0, was the second system-level integrated prototype of the advanced PLSS design, following the PLSS 1.0 Breadboard that was developed and tested throughout 2011. Whereas PLSS 1.0 included five technology development components with the balance the system simulated using commercial-off-the-shelf items, PLSS 2.0 featured first generation or later prototypes for all components less instrumentation, tubing and fittings. Developed throughout 2012, PLSS 2.0 was the first attempt to package the system into a flight-like representative volume. PLSS 2.0 testing included an extensive functional evaluation known as Pre-Installation Acceptance (PIA) testing, Human-in-the-Loop testing in which the PLSS 2.0 prototype was integrated via umbilicals to a manned prototype space suit for 19 two-hour simulated EVAs, and unmanned vacuum environment testing. Unmanned vacuum environment testing took place from 1/9/15-7/9/15 with PLSS 2.0 located inside a vacuum chamber. Test sequences included performance mapping of several components, carbon dioxide removal evaluations at simulated intravehicular activity (IVA) conditions, a regulator pressure schedule assessment, and culminated with 25 simulated extravehicular activities (EVAs). During the unmanned vacuum environment test series, PLSS 2.0 accumulated 378 hours of integrated testing including 291 hours of operation in a vacuum environment and 199 hours of simulated EVA time. The PLSS prototype performed nominally throughout the test series, with two notable exceptions including a pump failure and a Spacesuit Water Membrane Evaporator (SWME) leak, for which post-test failure investigations were performed. In addition to generating an extensive database of PLSS 2.0 performance data, achievements included requirements and

Second generation "Flat-Fish" vacuum chamber for an ISR intersection

CERN Multimedia

CERN PhotoLab

1977-01-01

The picture shows the part of the "Flat-Fish" chamber covering one side of the beam intersection region. The other side is covered by an equal part and both are welded toghether at their small end. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of stainless steel strings to the Split Field Magnet poles in order to take the atmospheric pressure forces. This was the thinnest vacuum chamber made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature.

Cold Vacuum Drying (CVD) OCRWM Loop Error Determination

International Nuclear Information System (INIS)

PHILIPP, B.L.

2000-01-01

Characterization is specifically identified by the Richland Operations Office (RL) for the Office of Civilian Radioactive Waste Management (OCRWM) of the US Department of Energy (DOE), as requiring application of the requirements in the Quality Assurance Requirements and Description (QARD) (RW-0333P DOE 1997a). Those analyses that provide information that is necessary for repository acceptance require application of the QARD. The cold vacuum drying (CVD) project identified the loops that measure, display, and record multi-canister overpack (MCO) vacuum pressure and Tempered Water (TW) temperature data as providing OCRWM data per Application of the Office of Civilian Radioactive Waste Management (OCRWM) Quality Assurance Requirements to the Hanford Spent Nuclear Fuel Project HNF-SD-SNF-RPT-007. Vacuum pressure transmitters (PT 1*08, 1*10) and TW temperature transmitters (TIT-3*05, 3*12) are used to verify drying and to determine the water content within the MCO after CVD

Design of large aperture, low mass vacuum windows

International Nuclear Information System (INIS)

Mapes, M.; Leonhardt, W.J.

1993-01-01

Large aperture, low mass, thin vacuum windows are required to minimize beam loss in the beam lines of particle accelerators as the products of nuclear collisions move from upstream targets to downstream detectors. This article describes the design, fabrication, testing, and operating experience of a large rectangular vacuum window, 122 cmx61 cm, and two circular windows of 91.4 and 96.5 cm diam. These window designs utilize a composite Kevlar 29 fabric and Mylar laminate as a window material with a typical combined thickness of 0.35 mm. Data for several material thicknesses are also presented. The windows are usually designed to withstand a pressure differential of two to three atmospheres to achieve the required factor of safety. These windows are typically used in the medium vacuum range of 10 -4 Torr. The equations used to predict the behavior of the window material will also be discussed

The application of vacuum redistillation of patchouli oil to improve patchouli alcohol compound

Science.gov (United States)

Asnawi, T. M.; Alam, P. N.; Husin, H.; Zaki, M.

2018-04-01

Patchouli oil produced by traditional distillation of patchouli leaves and stems by farmers in Aceh still has low patchouli alcohol compound. In order to increase patchouli alcohol concentration, vacuum redistillation process using packed column was introduced. This research was conducted to fractionate terpene (alpha-copinene) from oxygenated hydrocarbon (patchouli alcohol) compound. The operation condition was conducted at two variables that was dependent variable and independent variable. The dependent variable was the 30 cm height distillation packed column, by using raschig ring with 8 mm x 8 mm dimension. And the independent variable was operating temperature 130 °C and 140 °C., vacuum pressure 143,61 mbar, 121,60 mbar and 88,59 mbar and operation time 2 hours, 3 hours and 5 hours. Total of treatments applied in this works were 3 x 3 x 3 or equal to 27 treatments. Patchouli oil used in this research was obtained from Desa Teladan-Lembah Seulawah, Aceh Province. The initial patchouli alcohol compound which analyzed with GC-MS contained 16,02% before treatment applied. After vacuum redistillation process treatment applied patchouli oil concentration increase up to 34,67%. Physico-chemical test of patchouli oil after vacuum redistillation is in accordance with SNI 06-23852006 standard.

The Wigner distribution function for squeezed vacuum superposed state

International Nuclear Information System (INIS)

Zayed, E.M.E.; Daoud, A.S.; AL-Laithy, M.A.; Naseem, E.N.

2005-01-01

In this paper, we construct the Wigner distribution function for a single-mode squeezed vacuum mixed-state which is a superposition of the squeezed vacuum state. This state is defined as a P-representation for the density operator. The obtained Wigner function depends, beside the phase-space variables, on the mean number of photons occupied by the coherent state of the mode. This mean number relates to the mean free path through a given relation, which enables us to measure this number experimentally by measuring the mean free path

Vacuum-ultraviolet circular dichroism spectrophotometer using synchrotron radiation

International Nuclear Information System (INIS)

Matsuo, K.; Fukuyama, T.; Yonehara, R.; Namatame, H.; Taniguchi, M.; Gekko, K.

2005-01-01

We have constructed a vacuum-ultraviolet circular dichroism (VUVCD) spectrophotometer using a synchrotron radiation and an assembled-type MgF 2 cell endurable under a high vacuum, to measure the CD spectra of biomaterials in aqueous solutions from 310 to 140 nm. To avoid the absorption of light by air and water vapor, all optical devices of the spectrophotometer were set up under a high vacuum (10 -4 Pa). A path length of the optical cell can be adjusted by various Teflon spacers in the range from 1.3 to 50 μm and its temperature can be controlled to an accuracy of ±1 deg. C over the range from -30 to 70 deg. C by a temperature-control unit using a Peltier thermoelectric element. The performance of the spectrophotometer and the optical cell constructed was tested by measuring the CD spectra of ammonium d-camphor-10-sulfonate, D- and L-isomers of amino acids, and myoglobin in aqueous solutions. The spectra obtained demonstrate that the optical system and the sample cell constructed operate normally under a high vacuum and provide useful information on the structure of biomolecules based on the higher energy chromophores

Development of a novel rf waveguide vacuum valve

CERN Document Server

Grudiev, A

2006-01-01

The development of a novel rf waveguide vacuum valve is presented. The rf design is based on the use of TE0n modes of circular waveguides. In the device, the TE01 mode at the input is converted into a mixture of several TE0n modes which provide low-loss rf power transmission across the vacuum valve gap, these modes are then converted back into the TE01 mode at the output. There are a number of advantages associated with the absence of surface fields in the region of the valve: • Possibility to use commercially available vacuum valves equipped with two specially designed mode converter sections. • No necessity for an rf contact between these two sections. • Increased potential for high power rf transmission. This technology can be used for all frequencies for which vacuum waveguides are used. In rectangular waveguides, mode converters from the operating mode into the TE01 mode and back again are necessary. Experimental results for the 30 GHz valves developed for the CLIC Test Facility 3 (CTF3) a...

A login shell interface for INFN-GRID

Energy Technology Data Exchange (ETDEWEB)

Pardi, S [INFN - Sezione di Napoli, Complesso di Monte S.Angelo - Via Cintia 80126 Napoli (Italy); Calloni, E; Rosa, R De; Garufi, F; Milano, L; Russo, G [Universita degli Studi di Napoli ' Federico M' , Dipartimento di Scienze Fisiche, Complesso di Monte S.Angelo - Via Cintia 80126 Napoli (Italy)], E-mail: silvio.pardi@na.infn.it

2008-12-15

The user interface is a crucial service to guarantee the Grid accessibility. The goal to achieve, is the implementation of an environment able to hide the grid complexity and offer a familiar interface to the final user. Currently many graphical interfaces have been proposed to simplify the grid access, but the GUI approach appears not very congenital to UNIX developers and users accustomed to work with command line interface. In 2004 the GridShell project proposed an extension of popular UNIX shells such as TCSH and BASH with features supporting Grid computing. Starting from the ideas included in GridShell, we propose IGSH (INFN-GRID SHELL) a new login shell for the INFN-GRID middleware, that interact with the Resource Broker services and integrates in a 'naturally way' the grid functionality with a familiar interface. The architecture of IGSH is very simple, it consist of a software layer on the top of the INFN-GRID middleware layer. When some operation is performed by the user, IGSH takes in charge to parse the syntax and translate it in the correspondents INFN-GRID commands according to some semantic rules specified in the next sections. The final user interacts with the underlying distributed infrastructure by using IGSH instead of his default login shell, with the sensation to work on a local machine.

A login shell interface for INFN-GRID

International Nuclear Information System (INIS)

Pardi, S; Calloni, E; Rosa, R De; Garufi, F; Milano, L; Russo, G

2008-01-01

The user interface is a crucial service to guarantee the Grid accessibility. The goal to achieve, is the implementation of an environment able to hide the grid complexity and offer a familiar interface to the final user. Currently many graphical interfaces have been proposed to simplify the grid access, but the GUI approach appears not very congenital to UNIX developers and users accustomed to work with command line interface. In 2004 the GridShell project proposed an extension of popular UNIX shells such as TCSH and BASH with features supporting Grid computing. Starting from the ideas included in GridShell, we propose IGSH (INFN-GRID SHELL) a new login shell for the INFN-GRID middleware, that interact with the Resource Broker services and integrates in a 'naturally way' the grid functionality with a familiar interface. The architecture of IGSH is very simple, it consist of a software layer on the top of the INFN-GRID middleware layer. When some operation is performed by the user, IGSH takes in charge to parse the syntax and translate it in the correspondents INFN-GRID commands according to some semantic rules specified in the next sections. The final user interacts with the underlying distributed infrastructure by using IGSH instead of his default login shell, with the sensation to work on a local machine.

The Diagnostic Value of the Vacuum Phenomenon during Hip Arthroscopy

Science.gov (United States)

Rath, Ehud; Gortzak, Yair; Schwarzkopf, Ran; Benkovich, Vadim; Cohen, Eugene; Atar, Dan

2011-01-01

The diagnostic value of the vacuum phenomenon between the femoral head and the acetabulum, and time frame of its occurrence after application of traction is an important clinical question. The resulting arthrogram may outline the shape, location, and extent of cartilage lesions prior to arthroscopy of the hip joint. The presence, duration, and diagnostic information of the vacuum phenomenon were evaluated in 24 hips that underwent arthroscopy. The operative diagnosis was compared to the results of imaging studies and to findings obtained during a traction trial prior to arthroscopy. Indications for arthroscopy included avascular necrosis, labral tears, loose bodies, osteoarthrosis, and intractable hip pain. In 22 hips the vacuum phenomenon developed within 30 seconds after application of traction. The most important data obtained from the vacuum phenomenon was the location and extent of femoral head articular cartilage detachment and the presence of nonossified loose bodies. The vacuum phenomenon did not reveal labral or acetabular cartilage pathology in any of these patients. The vacuum phenomenon obtained during the trial of traction can add valuable information prior to hip arthroscopy. Femoral head articular cartilage detachment was best documented by this method. The hip arthroscopist should utilize this diagnostic window routinely prior to hip arthroscopy. PMID:24977068

ITER cryostat main chamber and vacuum vessel pressure suppression system design

International Nuclear Information System (INIS)

Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke; Nakashima, Yoshitane; Ueno, Osamu

1999-03-01

Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10 -4 Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

ITER cryostat main chamber and vacuum vessel pressure suppression system design

Energy Technology Data Exchange (ETDEWEB)

Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakashima, Yoshitane; Ueno, Osamu

1999-03-01

Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10{sup -4} Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

Design of dry scroll vacuum pumping system for efficient pumping of corrosive gas at medium vacuum range

International Nuclear Information System (INIS)

Banerjee, I.; Chandresh, B.G.; Guha, K.C.; Sarkar, S.

2015-01-01

Dry vacuum pumping systems attracts many applications because of its inherent capability of corrosion free pumping. It becomes a common trait of application in Thermo Nuclear Fusion, Semi conductor, Isotope separation industries etc. Thermo nuclear fusion requires a train of specially sealed roots pump backed by suitable capacity dry screw or reciprocating pump. Similarly corrosive fluoride gas pumping requires hermetically sealed specially designed dry scroll vacuum pump. Plant emergency operation however involves train of specially sealed roots pump backed with scroll pump for faster evacuation. In our attempt an indigenously designed scroll pump and associated system are designed to pump corrosive gases in a way to confine the corrosion product within the system. In order to execute the design, a numerical code for low pressure application is developed

Vacuum mammotomy under ultrasound guidance

International Nuclear Information System (INIS)

Luczynska, E.; Kocurek, A.; Pawlik, T.; Aniol, J.; Herman, K.; Skotnicki, P.

2007-01-01

Breast ultrasound is a non-invasive method of breast examination. You can use it also for fine needle biopsy, core needle biopsy, vacuum mammotomy and for placing the '' wire '' before open surgical biopsy. 106 patients (105 women and 1 man) aged 20-71 years (mean age 46.9) were treated in Cancer Institute in Cracow by vacuum mammotomy under ultrasound guidance. The lesions found in ultrasonography were divided into three groups: benign lesions (BI RADS II), ambiguous lesions (BI RADS 0, III and IVa), and suspicious lesions (BI RADS IV B, IV C and V). Then lesions were qualified to vacuum mammotomy. According to USG, fibroadenoma or '' fibroadenoma-like '' lesions were found in 75 women, in 6 women complicated cysts, in 6 women cyst with dense fluid (to differentiate with FA), and in 19 patients undefined lesions. Fibroadenoma was confirmed in histopathology in 74% patients among patients with fibroadenoma or '' fibroadenoma-like '' lesions in ultrasound (in others also benign lesions were found). Among lesions undefined after ultrasound examination (total 27 patients) cancer was confirmed in 6 % (DCIS and IDC). In 6 patients with complicated cysts in ultrasound examination, histopathology confirmed fibroadenoma in 4 women, an intraductal lesion in 1 woman and inflamatory process in 1 woman. Also in 6 women with a dense cyst or fibroadenoma seen in ultrasound, histopathology confirmed fibroadenoma in 3 women and fibrosclerosis in 3 women. Any breast lesions undefined or suspicious after ultrasound examination should be verified. The method of verification or kind of operation of the whole lesion (vacuum mammotomy or '' wire '') depends on many factors, for example: lesion localization; lesion size; BI RADS category. (author)

Cosmic vacuum

International Nuclear Information System (INIS)

Chernin, Artur D

2001-01-01

Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered. (reviews of topical problems)

Cosmic vacuum

Energy Technology Data Exchange (ETDEWEB)

Chernin, Artur D [P.K. Shternberg State Astronomical Institute at the M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

2001-11-30

Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered. (reviews of topical problems)

The design of high vacuum system for baby electron beam machine (baby ebm): a comparison between theoretical and experimental

International Nuclear Information System (INIS)

Mohd Rizal Mamat; Rosli Darmawan; Lee Chee Huei; Mohd Rizal Md Chulan; Leo Kwee Wah; Muhamad Zahidee Taat; Fadzlie Nordin; Abu Bakar Mhd Ghazali

2005-01-01

Baby ebm which was developed to study the engineering and physics of electrons requires the use of high vacuum system in order to prevent electron loss and ionization of air molecules. In selecting the high vacuum system for baby ebm two main factors were considered: the ultimate pressure and the pump down time. The ultimate pressure required for the operation of the baby ebm is in 10-7 torr range. The pump down time was estimated from calculations, taking into account the vacuum pump and chamber size. The turbomolecular pump system (tmp), which is capable of achieving the required vacuum level was selected as the high vacuum system and installed to baby ebm. The tmp is currently fully operational. It was found that the vacuum pumping performance of the tmp differs considerably from what the calculations indicate. Compared to the calculations, it takes a much longer time to achieve the required operating pressure of baby ebm. This could be due to the fact that the formula used for the calculations was a very simplified formula that takes into account the main factors only which are the vacuum pump and chamber size. This paper attempts to present the comparison of the tmp performance between the theoretical and experimental. (Author)

REQUIREMENTS AND GUIDELINES FOR NSLS EXPERIMENTAL BEAM LINE VACUUM SYSTEMS-REVISION B.

Energy Technology Data Exchange (ETDEWEB)

FOERSTER,C.

1999-05-01

Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas after a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, more energetic photons of the x-ray ring, beryllium windows are used at various beam line locations so that the monochromator, mirror box or sample chamber may be used in a helium atmosphere or rough vacuum. The window separates ring vacuum from the environment of the downstream beam line components. The stored beam lifetime in the storage rings and the maintenance of desirable reflection properties of optical surfaces depend upon hydrocarbon-free, ultra-high vacuum systems. Storage ring vacuum systems will operate at pressures of {approximately} 1 x 10{sup {minus}10} Torr without beam and {approximately} 1 x 10{sup {minus}9} Torr with beam. Systems are free of hydrocarbons in the sense that no pumps, valves, etc. containing organics are used. Components are all-metal, chemically cleaned and bakeable. To the extent that beam lines share a common vacuum with the storage ring, the same criteria will hold for beam line components. The design philosophy for NSLS beam lines is to use all-metal, hydrocarbon-free front end components and recommend that experimenters use this approach for common vacuum hardware

Advanced performance of small diaphragm vacuum pumps through the use of mechatronics

Science.gov (United States)

Lachenmann, R.; Dirscherl, J.

Oil-free diaphragm vacuum pumps have proven to be the best way in vacuum generation for the chemical laboratory and they also find increasing use as backing pumps for modern wide-range turbo molecular pumps. The majority of vacuum pumps in practical use pump only a rather small percentage of their lifetime at full gas load. A pump backing a turbo molecular pump does not have to pump a significant gas load when the high-vacuum pump is running at ultimate vacuum pressure. Also, for a vacuum distillation the vacuum pump has to operate at full speed only at the beginning to lower the pressure inside the system to a vacuum level where evaporation starts. In a rather leak-tight system the distillation process continues by evaporating from the hot liquid and condensing at the cold condenser without the need of a mechanical vacuum pump. Rotational speed controlled diaphragm pumps are now available through progress in mechatronics and offer high pumping speed capability for fast pump-down cycles and precise pressure control for distillations. At low gas load the rotational speed can be reduced, improving maintenance intervals, power consumption, noise, vibration and - surprisingly - also ultimate pressure. The different behaviour in pumping speed and ultimate pressure of rotational speed controlled diaphragm pumps in comparison to constant-speed pumps is related to the mechanical properties of the valves and gas dynamics .

Vacuum level effects on gait characteristics for unilateral transtibial amputees with elevated vacuum suspension.

Science.gov (United States)

Xu, Hang; Greenland, Kasey; Bloswick, Donald; Zhao, Jie; Merryweather, Andrew

2017-03-01

The elevated vacuum suspension system has demonstrated unique health benefits for amputees, but the effect of vacuum pressure values on gait characteristics is still unclear. The purpose of this study was to investigate the effects of elevated vacuum levels on temporal parameters, kinematics and kinetics for unilateral transtibial amputees. Three-dimensional gait analysis was conducted in 9 unilateral transtibial amputees walking at a controlled speed with five vacuum levels ranging from 0 to 20inHg, and also in 9 able-bodied subjects walking at self-preferred speed. Repeated ANOVA and Dunnett's t-test were performed to determine the effect of vacuum level and limb for within subject and between groups. The effect of vacuum level significantly affected peak hip external rotation and external knee adduction moment. Maximum braking and propulsive ground reaction forces generally increased for the residual limb and decreased for the intact limb with increasing vacuum. Additionally, the intact limb experienced an increased loading due to gait asymmetry for several variables. There was no systematic vacuum level effect on gait. Higher vacuum levels, such as 15 and 20inHg, were more comfortable and provided some relief to the intact limb, but may also increase the risk of osteoarthritis of the residual limb due to the increased peak external hip and knee adduction moments. Very low vacuum should be avoided because of the negative effects on gait symmetry. A moderate vacuum level at 15inHg is suggested for unilateral transtibial amputees with elevated vacuum suspension. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pressure measurements in the AGS Booster ultra-high vacuum system

International Nuclear Information System (INIS)

Gabusi, J.; Geller, J.; Hseuh, H.C.; Mapes, M.; Stattel, P.

1992-01-01

An average pressure of mid 10 -11 Torr has been achieved and maintained in the AGS Booster ring vacuum system during its first year of operation. This ultra-high vacuum system is monitored through remote controlled Bayard-Alpert Gauges (BAGs). The characteristics of the pressure measurements with BAGs over the long cable lengths (up to 200 m) and under various accelerator operating conditions will be described. Two types of noise in the pressure readouts have been identified; the electromagnetic interference (EMI) associated with the acceleration cycles of the Booster and the environment noise associated with the temperature of the collector cables. The magnitude of the noise pickup depends on the routing of the collector cables and reaches the equivalent pressure of low 10 -9 Torr

Synthesis of soft shell poly(styrene) colloids for filtration experiments

DEFF Research Database (Denmark)

Hinge, Mogens

Separating a solid from a liquid is an important unit operation in many different industries e.g. mining, chemical, pharmaceutical and food industries. Solid liquid separation can roughly be divided into three groups. 1) Separation by gravity forces e.g. sedimentation, centrifugation, 2) Separation...... consisting of a solid poly(styrene) (PS) core with a water swollen shell have been employed in investigating the effect from varying amounts and type of water swollen material on filtration dewatering properties. Three series of model material have been used in this investigation 1) poly......(styrene-co-acrylic acid) core-shell colloids with varying thickness of the poly(acrylic acid) (PAA) shell. 2) poly(styrene-co-acrylic acid) core-shell colloids with varying diameter of the PS core and 3) poly(styrene-co-N-isopropylacrylamide) core-shell colloids with varying thickness of the poly...

K-shell ionization and double-ionization of Au atoms with 1.33 MeV photons

International Nuclear Information System (INIS)

Belkacem, A.; Dauvergne, D.; Feinberg, B.; Ionescu, D.; Maddi, J.; Sorensen, A.H.

2000-01-01

At relativistic energies, the cross section for the atomic photoelectric effect drops off as does the cross section for liberating any bound electron through Compton scattering. However, when the photon energy exceeds twice the rest mass of the electron, ionization may proceed via electron-positron pair creation. We used 1.33 MeV photons impinging on Au thin foils to study double K-shell ionization and vacuum-assisted photoionization. The preliminary results yield a ratio of vacuum-assisted photoionization and pair creation of 2x10 -3 , a value that is substantially higher than the ratio of photo double ionization to single photoionization that is found to be 0.5-1x10 -4 . Because of the difficulties and large error bars associated with the small cross sections additional measurements are needed to minimize systematic errors

Function and operation of the Doublet III E-coil vacuum breaker system

International Nuclear Information System (INIS)

Callis, R.W.; Jackson, G.; DeGrassie, J.; Peterson, P.; LeVine, F.

1979-11-01

The ohmic heating system for the Doublet III fusion research device at General Atomic is required to provide the voltage for the initial breakdown phase (there is no preionization) along with the energy to drive the plasma current to a value of 2.5 MA or greater. This requires a peak one turn voltage of 250 volts (16 kV across coil terminals) and a magnetic flux swing of 5 volt-seconds (peak coil current of 110 kA). This voltage and flux swing is accomplished by reverse biasing the ohmic heating coil (E-coil) where, upon reaching a value of 110 ka the coil current is interrupted and commutated into a RC network producing 16 kV across the coil. The interrruption of the E-coil current is accomplished by the use of an array of vacuum circuit breakers (VCB's) and a counter plus network. A description is given of the ohmic heating circuit and the performance of the vacuum circuit breaker array and its counter pulse system

Introduction to vacuum technology: supplementary study material developed for IVS sponsored vacuum courses

International Nuclear Information System (INIS)

Bhusan, K.G.

2008-01-01

Vacuum technology has advanced to a large extent mainly from the demands of experimental research scientists who have more than ever understood the need for clean very low pressure environments. This need only seems to increase as the lowest pressures achievable in a laboratory setup are dropping down by the decade. What is not usually said is that conventional techniques of producing ultrahigh vacuum have also undergone a metamorphosis in order to cater to the multitude of restrictions in modern day scientific research. This book aims to give that practical approach to vacuum technology. The basics are given in the first chapter with more of a definition oriented approach - which is practically useful. The second chapter deals with the production of vacuum and ultrahigh vacuum with an emphasis on the working principles of several pumps and their working pressure ranges. Measurement of low pressures, both total and partial is presented in the third chapter with a note on leak detection and mass spectrometric techniques. Chapter 4 gives an overview of the materials that are vacuum compatible and their material properties. Chapter 5 gives the necessary methods to be followed for cleaning of vacuum components especially critical if ultrahigh vacuum environment is required. The practical use of a ultrahigh vacuum environment is demonstrated in Chapter 6 for production of high quality thin films through vapour deposition

Assessment of differences between products obtained in conventional and vacuum spray dryer

Directory of Open Access Journals (Sweden)

Fernanda de Melo RAMOS

Full Text Available Abstract In this work, an experimental unit of a vacuum spray dryer was built. This prototype attempted to combine the advantages of freeze-drying (drying at low temperatures due to vacuum and spray drying (increase of surface area aiming the improvement of heat transfer efficiency. Maltodextrin solutions were dried in the vacuum operated equipment and in conventional spray dryer. The vacuum spray dryer system allowed obtaining powder at low temperatures due to the lowering of pressure conditions (2-5 kPa inside the drying chamber. The products obtained in the two systems were characterized and compared for particle size distribution, moisture content, water activity, bulk density and solubility in water. The processes yields were also evaluated and compared. The vacuum spray dryer system allowed the production of larger, more soluble and less dense particles than those obtained in the conventional configuration of the equipment, resulting in drier and, therefore, with lower water activity particles. Thus, the use of the vacuum spray dryer as a drying technique may be an alternative for the production of powder rich in thermosensitive compounds.

EAST-AIA deployment under vacuum: Calibration of laser diagnostic system using computer vision

Energy Technology Data Exchange (ETDEWEB)

Yang, Yang, E-mail: yangyang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, 350 Shushanhu Rd, Hefei, Anhui (China); Song, Yuntao; Cheng, Yong; Feng, Hansheng; Wu, Zhenwei; Li, Yingying; Sun, Yongjun; Zheng, Lei [Institute of Plasma Physics, Chinese Academy of Sciences, 350 Shushanhu Rd, Hefei, Anhui (China); Bruno, Vincent; Eric, Villedieu [CEA-IRFM, F-13108 Saint-Paul-Lez-Durance (France)

2016-11-15

Highlights: • The first deployment of the EAST articulated inspection arm robot under vacuum is presented. • A computer vision based approach to measure the laser spot displacement is proposed. • An experiment on the real EAST tokamak is performed to validate the proposed measure approach, and the results shows that the measurement accuracy satisfies the requirement. - Abstract: For the operation of EAST tokamak, it is crucial to ensure that all the diagnostic systems are in the good condition in order to reflect the plasma status properly. However, most of the diagnostic systems are mounted inside the tokamak vacuum vessel, which makes them extremely difficult to maintain under high vacuum condition during the tokamak operation. Thanks to a system called EAST articulated inspection arm robot (EAST-AIA), the examination of these in-vessel diagnostic systems can be performed by an embedded camera carried by the robot. In this paper, a computer vision algorithm has been developed to calibrate a laser diagnostic system with the help of a monocular camera at the robot end. In order to estimate the displacement of the laser diagnostic system with respect to the vacuum vessel, several visual markers were attached to the inner wall. This experiment was conducted both on the EAST vacuum vessel mock-up and the real EAST tokamak under vacuum condition. As a result, the accuracy of the displacement measurement was within 3 mm under the current camera resolution, which satisfied the laser diagnostic system calibration.

Grassmannian integral for general gauge invariant off-shell amplitudes in N=4 SYM

Energy Technology Data Exchange (ETDEWEB)

Bork, L.V. [Institute for Theoretical and Experimental Physics,Moscow (Russian Federation); The Center for Fundamental and Applied Research,All-Russia Research Institute of Automatics, Moscow (Russian Federation); Onishchenko, A.I. [Bogoliubov Laboratory of Theoretical Physics,JointInstitute for Nuclear Research, Dubna (Russian Federation); Moscow Institute of Physics and Technology, State University,Dolgoprudny (Russian Federation); Skobeltsyn Institute of Nuclear Physics, Moscow State University,Moscow (Russian Federation)

2017-05-08

In this paper we consider tree-level gauge invariant off-shell amplitudes (Wilson line form factors) in N=4 SYM with arbitrary number of off-shell gluons or equivalently Wilson line operator insertions. We make a conjecture for the Grassmannian integral representation for such objects and verify our conjecture on several examples. It is remarkable that in our formulation one can consider situation when on-shell particles are not present at all, i.e. we have Grassmannian integral representation for purely off-shell object. In addition we show that off-shell amplitude with arbitrary number of off-shell gluons could be also obtained using quantum inverse scattering method for auxiliary gl(4|4) super spin chain.

A safety equipment list for rotary mode core sampling systems operation in single shell flammable gas tanks; TOPICAL

International Nuclear Information System (INIS)

SMALLEY, J.L.

1999-01-01

This document identifies all interim safety equipment to be used for rotary mode core sampling of single-shell flammable gas tanks utilizing Rotary Mode Core Sampling systems (RMCS). This document provides the safety equipment for RMCS trucks HO-68K-4600, HO-68K-4647, trucks three and four respectively, and associated equipment. It is not intended to replace or supersede WHC-SD-WM-SEL-023, (Kelly 1991), or WHC-SD-WM-SEL-032, (Corbett 1994), which classifies 80-68K-4344 and HO-68K-4345 respectively. The term ''safety equipment'' refers to safety class (SC) and safety significant (SS) equipment, where equipment refers to structures, systems and components (SSC's). The identification of safety equipment in this document is based on the credited design safety features and analysis contained in the Authorization Basis (AB) for rotary mode core sampling operations in single-shell flammable gas tanks. This is an interim safety classification since the AB is interim. This document will be updated to reflect the final RMCS equipment safety classification designations upon completion of a final AB which will be implemented with the release of the Final Safety Analysis Report (FSAR)

The vacuum platform

Science.gov (United States)

McNab, A.

2017-10-01

This paper describes GridPP’s Vacuum Platform for managing virtual machines (VMs), which has been used to run production workloads for WLCG and other HEP experiments. The platform provides a uniform interface between VMs and the sites they run at, whether the site is organised as an Infrastructure-as-a-Service cloud system such as OpenStack, or an Infrastructure-as-a-Client system such as Vac. The paper describes our experience in using this platform, in developing and operating VM lifecycle managers Vac and Vcycle, and in interacting with VMs provided by LHCb, ATLAS, ALICE, CMS, and the GridPP DIRAC service to run production workloads.

Removal of salt from rare earth precipitates by vacuum distillation

International Nuclear Information System (INIS)

Yang, Hee-Chul; Eun, Hee-Chul; Cho, Yong-Zun; Park, Hwan-Seo; Kim, In-Tae

2008-01-01

This study investigated the distillation rates of LiCl-KCl eutectic salt from the rare earth (RE) precipitates originating from the oxygen-sparging RE precipitation process. The first part study investigated distillation rates of eutectic salt under different vacuums at high temperatures by using thermo-gravimetric furnace system. The second part study tested the removal efficiency of eutectic salt from RE precipitates by using the laboratory vacuum distillation furnace system. Investigated variables were the temperature, the degree of vacuum and the time. Salt distillation operation with a moderated distillation rate of 10 -4 - 10 -5 mole sec -1 cm -2 is possible at temperature less than 1300 K and vacuums of 5-50 Torr, by minimizing the potentials of the RE particle entrainment. An increase in the vaporizing surface area is relatively effective for removing the residual salt in pores of bulk of the precipitated RE particles, when compared to that for the vaporizing time. Over 99.9% of the salt removal from the salt-RE precipitate mixture could be achieved by increasing the vaporizing surface area under moderate vacuum conditions of 50 Torr at 1200 K. (author)

Core-shell microspheres with porous nanostructured shells for liquid chromatography.

Science.gov (United States)

Ahmed, Adham; Skinley, Kevin; Herodotou, Stephanie; Zhang, Haifei

2018-01-01

The development of new stationary phases has been the key aspect for fast and efficient high-performance liquid chromatography separation with relatively low backpressure. Core-shell particles, with a solid core and porous shell, have been extensively investigated and commercially manufactured in the last decade. The excellent performance of core-shell particles columns has been recorded for a wide range of analytes, covering small and large molecules, neutral and ionic (acidic and basic), biomolecules and metabolites. In this review, we first introduce the advance and advantages of core-shell particles (or more widely known as superficially porous particles) against non-porous particles and fully porous particles. This is followed by the detailed description of various methods used to fabricate core-shell particles. We then discuss the applications of common silica core-shell particles (mostly commercially manufactured), spheres-on-sphere particles and core-shell particles with a non-silica shell. This review concludes with a summary and perspective on the development of stationary phase materials for high-performance liquid chromatography applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hi shells, supershells, shell-like objects, and ''worms''

International Nuclear Information System (INIS)

Heiles, C.

1984-01-01

We present photographic representations of the combination of two Hi surveys, so as to eliminate the survey boundaries at Vertical BarbVertical Bar = 10 0 . We also present high-contrast photographs for particular velocities to exhibit weak Hi features. All of these photographs were used to prepare a new list of Hi shells, supershells, and shell-like objects. We discuss the structure of three shell-like objects that are associated with high-velocity gas, and with gas at all velocities that is associated with radio continuum loops I, II, and III. We use spatial filtering to find wiggly gas filaments: ''worms'': crawling away from the galactic plane in the inner Galaxy. The ''worms'' are probably parts of shells that are open at the top; such shells should be good sources of hot gas for the galactic halo

Vacuum fluctuations in an ancestor vacuum: A possible dark energy candidate

Science.gov (United States)

Aoki, Hajime; Iso, Satoshi; Lee, Da-Shin; Sekino, Yasuhiro; Yeh, Chen-Pin

2018-02-01

We consider an open universe created by bubble nucleation, and study possible effects of our "ancestor vacuum," a de Sitter space in which bubble nucleation occurred, on the present universe. We compute vacuum expectation values of the energy-momentum tensor for a minimally coupled scalar field, carefully taking into account the effect of the ancestor vacuum by the Euclidean prescription. We pay particular attention to the so-called supercurvature mode, a non-normalizable mode on a spatial slice of the open universe, which has been known to exist for sufficiently light fields. This mode decays in time most slowly, and may leave residual effects of the ancestor vacuum, potentially observable in the present universe. We point out that the vacuum energy of the quantum field can be regarded as dark energy if mass of the field is of order the present Hubble parameter or smaller. We obtain preliminary results for the dark energy equation of state w (z ) as a function of the redshift.

Design for ANL 7 GeV storage ring vacuum system

International Nuclear Information System (INIS)

Wehrle, R.B.; Nielsen, R.W.

1988-01-01

The 7-GeV Advanced Photon Source (APS) design includes a storage ring having a 1060-m circumference with the capability of accommodating 34 insertion devices (ID) and their associated photon beam lines. An additional 35 photon lines can be provided from bending magnets. The vacuum system for the storage ring is designed to maintain a beam-on operating pressure of 1n Torr or less to achieve a positron beam lifetime of approximately 20 hours. The vacuum system and it's current developmental status are described

Progress and Achievements on the R&D Activities for ITER Vacuum Vessel

Energy Technology Data Exchange (ETDEWEB)

Nakahira, M. [Japan Atomic Energy Research Institute (JAERI); Koizumi, K. [Japan Atomic Energy Research Institute (JAERI); Takahashi, H. [Japan Atomic Energy Research Institute (JAERI); Onozuka, M. [ITER Joint Central Team, Garching, Germany; Ioki, K. [ITER Joint Central Team, Garching, Germany; Kuzumin, E. [D.V. Efremov Scientific Research Institute, St. Petersburg, Russia; Krylov, V. [D.V. Efremov Scientific Research Institute, St. Petersburg, Russia; Maslakowski, J. [Oak Ridge National Laboratory (ORNL); Nelson, Brad E [ORNL; Jones, L. [Max-Planck Institute, Garching, Germany; Danner, W. [Max-Planck Institute, Garching, Germany; Maisonnier, D. [Max-Planck Institute, Garching, Germany

2001-01-01

The ITER vacuum vessel (VV) is designed to be large double-walled structure with a D-shaped crosssection. The achievable fabrication tolerance of this structure was unknown due to the size and complexity of shape. The Full-scale Sector Model of ITER Vacuum Vessel, which was 15m in height, was fabricated and tested to obtain the fabrication and assembly tolerances. The model was fabricated within the target tolerance of 5mm and welding deformation during assembly operation was obtained. The port structure was also connected using remotized welding tools to demonstrate the basic maintenance activity. In parallel, the tests of advanced welding, cutting and inspection system were performed to improve the efficiency of fabrication and maintenance of the Vacuum Vessel. These activities show the feasibility of ITER Vacuum Vessel as feasible in a realistic way. This paper describes the major progress, achievement and latest status of the R&D activities on the ITER vacuum vessel.

LLNL Tandem Mirror Experiment (TMX) upgrade vacuum system

International Nuclear Information System (INIS)

Pickles, W.L.; Chargin, A.K.; Drake, R.P.

1981-01-01

TMX Upgrade is a large, tandem, magnetic-mirror fusion experiment with stringent requirements on base pressure (10 -8 torr), low H reflux from the first walls, and peak gas pressure (5 x 10 -7 torr) due to neutral beam gas during plasma operation. The 225 m 3 vacuum vessel is initially evacuated by turbopumps. Cryopumps provide a continuous sink for gases other than helium, deuterium, and hydrogen. The neutral beam system introduces up to 480 l/s of H or D. The hydrogen isotopes are pumped at very high speed by titanium sublimed onto two cylindrical radially separated stainless steel quilted liners with a total surface area of 540 m 2 . These surfaces (when cooled to about 80 0 K) provide a pumping speed of 6 x 10 7 l/s for hydrogen. The titanium getter system is programmable and is used for heating as well as gettering. The inner plasma liner can be operated at elevated temperatures to enhance migration of gases away from the surfaces close to the plasma. Glow discharge cleaning is part of the pumpdown procedure. The design features are discussed in conjunction with the operating procedures developed to manage the dynamic vacuum conditions

Changing MFTF vacuum environment

International Nuclear Information System (INIS)

Margolies, D.; Valby, L.

1982-01-01

The Mirror Fusion Test Facility (MFTF) vaccum vessel will be about 60m long and 10m in diameter at the widest point. The allowable operating densities range from 2 x 10 9 to 5 x 10 10 particles per cc. The maximum leak rate of 10 -6 tl/sec is dominated during operation by the deliberately injected cold gas of 250 tl/sec. This gas is pumped by over 1000 square meters of cryopanels, external sorbtion pumps and getters. The design and requirements have changed radically over the past several years, and they are still not in final form. The vacuum system design has also changed, but more slowly and less radically. This paper discusses the engineering effort necessary to meet these stringent and changing requirements. Much of the analysis of the internal systems has been carried out using a 3-D Monte Carlo computer code, which can estimate time dependent operational pressures. This code and its use will also be described

Quantum measurement information as a key to energy extraction from local vacuums

International Nuclear Information System (INIS)

Hotta, Masahiro

2008-01-01

In this paper, a protocol is proposed in which energy extraction from local vacuum states is possible by using quantum measurement information for the vacuum state of quantum fields. In the protocol, Alice, who stays at a spatial point, excites the ground state of the fields by a local measurement. Consequently, wave packets generated by Alice's measurement propagate the vacuum to spatial infinity. Let us assume that Bob stays away from Alice and fails to catch the excitation energy when the wave packets pass in front of him. Next Alice announces her local measurement result to Bob by classical communication. Bob performs a local unitary operation depending on the measurement result. In this process, positive energy is released from the fields to Bob's apparatus of the unitary operation. In the field systems, wave packets are generated with negative energy around Bob's location. Soon afterwards, the negative-energy wave packets begin to chase after the positive-energy wave packets generated by Alice and form loosely bound states.

Spent nuclear fuel project cold vacuum drying facility process water conditioning system design description

International Nuclear Information System (INIS)

IRWIN, J.J.

1998-01-01

This document provides the System Design Description (SDD) for the Cold Vacuum Drying Facility (CVDF) Process Water Conditioning (PWC) System. The SDD was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of Processing Systems (Garvin 1998), the HNF-SD-SNF-DRD-O02, 1998, Cold Vacuum Drying Facility Design Requirements, and the CVDF Design Summary Report. The SDD contains general descriptions of the PWC equipment, the system functions, requirements and interfaces. The SDD provides references for design and fabrication details, operation sequences and maintenance. This SDD has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

Does vacuum delivery carry a higher risk of shoulder dystocia? Review and meta-analysis of the literature.

Science.gov (United States)

Dall'Asta, Andrea; Ghi, Tullio; Pedrazzi, Giuseppe; Frusca, Tiziana

2016-09-01

Vacuum extractor has been increasingly used over the last decades and is acknowledged as a risk factor for shoulder dystocia (SD). In this meta-analysis we assess the actual risk of SD following a vacuum delivery compared to spontaneous vaginal delivery (SVD) and forceps. Systematic literature search (English literature only) on MEDLINE, EMBASE, ScienceDirect, the Cochrane library and ClinicalTrials.gov conducted up to May 2015. Key search terms included: Operative/Vacuum/Forceps delivery [Mesh] and shoulder dystocia and subheadings. 2 stage-process study selection. We included only studies where data concerning the occurrence of SD following operative vaginal delivery were reported as adjusted odds ratio (AOR) and no significant difference in confounding factors for SD was recorded. Included trials clustered according to the delivery mode (1) vacuum vs. SVD, (2) forceps vs. vacuum. Methodological quality of each study evaluated with the Newcastle-Ottawa System (NOS). 87 potentially relevant papers. After applying inclusion and exclusion criteria only 7 were selected for the meta-analysis. Vacuum delivery appeared associated with a higher risk of SD than SVD in both fixed and random model (OR 2.87 and 2.98 respectively). No difference in the rate of SD was found between vacuum and forceps (p>0.05). Vacuum extractor carries an increased risk of SD compared with spontaneous vaginal delivery whereas the occurrence of SD does not seem to vary following vacuum or forceps. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Calculations in the tokamak vacuum region: δWυ and diagnostic capabilities

International Nuclear Information System (INIS)

Chance, M.S.

1993-01-01

The calculational methods used for the magnetic energy, δW v , in the vacuum region surrounding tokamak plasmas permit a natural extension to more general toroidal configurations, and also for calculating useful ancillary quantities like the simulation of the Mirnov-loop measurements, and the eddy currents generated in the conducting materials outside the plasma discharge. The generalizations include the capabilities for topologically spherical shells, and toroidally symmetric unlinked (with respect to the plasma discharge) solid conductors. The former was motivated by spheromak-like configurations, and the latter for simulating the segmented shell of PBX-M. The collocation method and Green's second identity is used for solving ∇ 2 χ = 0 for the magnetic scalar potential. This lends itself readily to incorporating the necessary boundary conditions, and once χ is known on the surfaces, a second application of Green's identity enables the simulation of the Mirnov-loop measurements. The eddy currents on the surface of the conductors, K c , is given by n x ∇χ. This is useful for visualizing the proposed coil currents needed for stabilizing the external kink modes by feedback mechanisms, and also for estimating the stresses in the shell due to disruptions, etc. The code is modular and can be easily interfaced to various stability codes like the PEST, NOVA, GATO, etc. system of codes, or can be used in a stand-alone mode for diagnostic purposes. Details of the numerical method and results are presented. These include the efficient treatment of the singularities inherently present in the Green's function method

Fast-opening vacuum switches for high-power inductive energy storage

International Nuclear Information System (INIS)

Cooperstein, G.

1988-01-01

The subject of fast-opening vacuum switches for high-power inductive energy storage is emerging as an exciting new area of plasma science research. This opening switch technology, which generally involves the use of plasmas as the switching medium, is key to the development of inductive energy storage techniques for pulsed power which have a number of advantages over conventional capacitive techniques with regard to cost and size. This paper reviews the state of the art in this area with emphasis on applications to inductive storage pulsed power generators. Discussion focuses on fast-opening vacuum switches capable of operating at high power (≥10 12 W). These include plasma erosion opening switches, ion beam opening switches, plasma filled diodes, reflex diodes, plasma flow switches, and other novel vacuum opening switches

Cold Vacuum Drying Instrument Air System Design Description. System 12

International Nuclear Information System (INIS)

SHAPLEY, B.J.; TRAN, Y.S.

2000-01-01

This system design description (SDD) addresses the instrument air (IA) system of the spent nuclear fuel (SNF). This IA system provides instrument quality air to the Cold Vacuum Drying (CVD) Facility. The IA system is a general service system that supports the operation of the heating, ventilation, and air conditioning (HVAC) system, the process equipment skids, and process instruments in the CVD Facility. The following discussion is limited to the compressor, dryer, piping, and valving that provide the IA as shown in Drawings H-1-82222, Cold Vacuum Drying Facility Mechanical Utilities Compressed and Instrument Air PandID, and H-1.82161, Cold Vacuum Drying Facility Process Equipment Skid PandID MCO/Cusk Interface. Figure 1-1 shows the physical location of the 1A system in the CVD Facility

Cold Vacuum Drying Instrument Air System Design Description (SYS 12)

Energy Technology Data Exchange (ETDEWEB)

SHAPLEY, B.J.; TRAN, Y.S.

2000-06-05

This system design description (SDD) addresses the instrument air (IA) system of the spent nuclear fuel (SNF). This IA system provides instrument quality air to the Cold Vacuum Drying (CVD) Facility. The IA system is a general service system that supports the operation of the heating, ventilation, and air conditioning (HVAC) system, the process equipment skids, and process instruments in the CVD Facility. The following discussion is limited to the compressor, dryer, piping, and valving that provide the IA as shown in Drawings H-1-82222, Cold Vacuum Drying Facility Mechanical Utilities Compressed & Instrument Air P&ID, and H-1.82161, Cold Vacuum Drying Facility Process Equipment Skid P&ID MCO/Cusk Interface. Figure 1-1 shows the physical location of the 1A system in the CVD Facility.

LHC vacuum upgrade during LS1

International Nuclear Information System (INIS)

Jimenez, J.M.; Baglin, V.; Chiggiato, P.; Cruikshank, P.; Gallilee, M.; Garion, C.; Gomes, P.

2012-01-01

The last two years of LHC operation have highlighted concerns on the levels of the dynamic vacuum in the long straight sections in presence of high intensity beams. The analysis of the existing data has shown relationship between pressures spikes and beam screen temperature oscillations or micro-sparking in the RF fingers of the bellows on one side and coincidence of pressure bumps with stimulated desorption by electron cloud, beam losses and/or thermal out gassing stimulated by higher order modes (HOM) losses. The electron cloud mitigation solutions will be adapted to the different configurations: cold/warm transitions, non-coated surfaces in direct view of beams, photoelectrons, etc. All scenarios will be presented together with their efficiencies. Additional pumping and re-engineering of components will reduce the sensitivity of the vacuum system to beam losses or HOM inducing out gassing. The expected margin at nominal intensity and energy resulting from these consolidations will be summarized. Finally, the challenges of the Experimental areas will be addressed, more specifically the status of the new Beryllium pipes (ATLAS and CMS) which are in the critical path and the consolidation of vacuum instrumentation, pumping and electron cloud mitigation. The risk corresponding to the proposed consolidations will be shown and the margins with respect to the schedule analysed. (authors)

Superconductivity, magnetics, cryogenics, and vacuum coating

International Nuclear Information System (INIS)

Akin, J.E.; Ballou, J.K.; Beaver, R.J.

1975-01-01

The Engineering Sciences Department continued to provide consultation, design, and experiment to support the plasma physics activities of the Division while inaugurating a comprehensive program to develop superconducting magnets for toroidal fusion devices. This newly funded program is aimed at producing toroidal superconducting magnets for an experimental power reactor by the mid 1980's. Other superconducting work, such as the 14-T niobium tin solenoid designed last year for use in Moessbauer experiments, has been fabricated, successfully tested, and delivered to the Physics Division. This coil, which used a 1.27-cm wide Nb 3 Sn conductor operating at 14 T with a coil current density of 11,000 A/cm, represents an advance in the state-of-the-art. The conceptual design was provided for a subcooler to extend the ORMAK operating temperature to 70 0 K and thus allow operation at fields up to 25 kG with the present generators. The detailed design, fabrication, installation supervision, and acceptance testing of the subcooler were provided by the UCCND engineering organization. Further support to the ORMAK program was provided by the vacuum-coating activity through an investigation of sputtering erosion of the ORMAK liner. In addition, a program was undertaken to develop a variety of refractory surfaces of metals, alloys, and intermetallic compounds on stainless steel for use as first walls in future fusion devices. Adherent thick-film metallic and compound coatings deposited in vacuum by several mechanisms were produced and tested. (U.S.)

Vacuum fusion of uranium; Fusion de l'uranium sous vide

Energy Technology Data Exchange (ETDEWEB)

Stohr, J. A.

1957-06-04

After having outlined that vacuum fusion and moulding of uranium and of its alloys have some technical and economic benefits (vacuum operations avoid uranium oxidation and result in some purification; precision moulding avoids machining, chip production and chemical reprocessing of these chips; direct production of the desired shape is possible by precision moulding), this report presents the uranium fusion unit (its low pressure enclosure and pumping device, the crucible-mould assembly, and the MF supply device). The author describes the different steps of cast production, and briefly comments the obtained results.

Vacuum boilers developed heating surfaces technic and economic efficiency evaluation

Science.gov (United States)

Slobodina, E. N.; Mikhailov, A. G.; Semenov, B. A.

2018-01-01

The vacuum boilers as manufacturing proto types application analysis was carried out, the possible directions for the heating surfaces development are identified with a view to improving the energy efficiency. Economic characteristics to evaluate the vacuum boilers application efficiency (Net Discounted Income (NDI), Internal Rate of Return (IRR), Profitability Index (PI) and Payback Period) are represented. The given type boilers application technic and economic efficiency criteria were established. NDI changing curves depending on the finning coefficient and operating pressure were obtained as a result of the conducted calculation studies.

Thermally Stable Gold Nanoparticles with a Crosslinked Diblock Copolymer Shell

Science.gov (United States)

Jang, Se Gyu; Khan, Anzar; Hawker, Craig J.; Kramer, Edward J.

2010-03-01

The use of polymer-coated Au nanoparticles prepared using oligomeric- or polymeric-ligands tethered by Au-S bonds for incorporation into block copolymer templates under thermal processing has been limited due to dissociation of the Au-S bond at T > 100^oC where compromises their colloidal stability. We report a simple route to prepare sub-5nm gold nanoparticles with a thermally stable polymeric shell. An end-functional thiol ligand consisting of poly(styrene-b-1,2&3,4-isoprene-SH) is synthesized by anionic polymerization. After a standard thiol ligand synthesis of Au nanoparticles, the inner PI block is cross-linked through reaction with 1,1,3,3-tetramethyldisiloxane. Gold nanoparticles with the cross-linked shell are stable in organic solvents at 160^oC as well as in block copolymer films of PS-b-P2VP annealed in vacuum at 170^oC for several days. These nanoparticles can be designed to strongly segregate to the PS-P2VP interface resulting in very large Au nanoparticle volume fractions φp without macrophase separation as well as transitions between lamellar and bicontinuous morphologies as φp increases.

Off-shell sensitivity, repulsive correlations and the pion-nucleus optical potential

Energy Technology Data Exchange (ETDEWEB)

Keister, B D [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

1977-07-01

Repulsive nucleon-nucleon correlations tend to reduce the dependence of pion-nucleus elastic scattering upon the off-shell pion-nucleon dynamics. However, optical potential calculations can in practice be quite sensitive to the particular choice of off-shell model parameters. It is argued that this sensitivity results from the nature of the optical potential as a one-body operator which introduces extra off-shell dependence not found in physical many-body process itself. Thus, one must be very careful in any attempt to extract correlation or off-shell information, or to predict pion-nucleus phase shifts, by means of an optical potential theory. Results of model calculations are presented for purposes of illustration.

A drift chamber with a new type of straws for operation in vacuum

Science.gov (United States)

Azorskiy, N.; Glonti, L.; Gusakov, Yu.; Elsha, V.; Enik, T.; Kakurin, S.; Kekelidze, V.; Kislov, E.; Kolesnikov, A.; Madigozhin, D.; Movchan, S.; Polenkevich, I.; Potrebenikov, Yu.; Samsonov, V.; Shkarovskiy, S.; Sotnikov, S.; Zinchenko, A.; Danielsson, H.; Bendotti, J.; Degrange, J.; Dixon, N.; Lichard, P.; Morant, J.; Palladino, V.; Gomez, F. Perez; Ruggiero, G.; Vergain, M.

2016-07-01

A 2150×2150 mm2 registration area drift chamber capable of working in vacuum is presented. Thin-wall tubes (straws) of a new type are used in the chamber. A large share of these 9.80 mm diameter drift tubes are made in Dubna from metalized 36 μm Mylar film welded along the generatrix using an ultrasonic welding machine created at JINR. The main features of the chamber and some characteristics of the drift tubes are described. Four such chambers with the X, Y, U, V coordinates each, containing 7168 straws in total, are designed and produced at JINR and CERN. They are installed in the vacuum volume of the NA62 setup in order to study the ultra-rare decay K+ →π+ vv bar and to search for and study rare meson decays. In autumn 2014 the chambers were used for the first time for the data taking in the experimental run of the NA62 at CERN's SPS.

Retrieval technology development for Hanford double-shell tanks

International Nuclear Information System (INIS)

Bamberger, J.A.; Wise, B.M.; Miller, W.C.

1992-05-01

This paper describes the combined analytical, computational, and experimental program developed for identifying operating strategies for mobilization and retrieval of radioactive waste stored in double-shell tanks at Hanford. Sludge mobilization, slurry uniformity, and slurry retrieval investigations will produce guidelines for mixer pump and retrieval pump operation based on the physical properties of the waste and the geometric properties of the system (number of operating pumps and pump design and placement)

Economical evaluation of damaged vacuum insulation panels in buildings

Science.gov (United States)

Kim, Y. M.; Lee, H. Y.; Choi, G. S.; Kang, J. S.

2015-12-01

In Korea, thermal insulation standard of buildings have been tightened annually to satisfy the passive house standard from the year 2009. The current domestic policies about disseminating green buildings are progressively conducted. All buildings should be the zero energy building in the year 2025, obligatorily. The method is applied to one of the key technologies for high-performance insulation for zero energy building. The vacuum insulation panel is an excellent high performance insulation. But thermal performance of damaged vacuum insulation panels is reduced significantly. In this paper, the thermal performance of damaged vacuum insulation panels was compared and analyzed. The measurement result of thermal performance depends on the core material type. The insulation of building envelope is usually selected by economic feasibility. To evaluate the economic feasibility of VIPs, the operation cost was analyzed by simulation according to the types and damaged ratio of VIPs

Influence of Gap Distance on Vacuum Arc Characteristics of Cup Type AMF Electrode in Vacuum Interrupters

International Nuclear Information System (INIS)

Cheng Shaoyong; Xiu Shixin; Wang Jimei; Shen Zhengchao

2006-01-01

The greenhouse effect of SF 6 is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling technique are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device (CCD) video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 mm. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters

Experiments with background gas in a vacuum arc centrifuge

International Nuclear Information System (INIS)

Dallaqua, R.S.; Simpson, S.W.; Del Bosco, E.

1996-01-01

Since promising isotope separation results were first reported by Krishnan et al. in 1981, a range of vacuum arc centrifuge experiments have been conducted in laboratories around the world. The PCEN (Plasma CENtrifuge) vacuum arc centrifuge at the Brazilian National Institute for Space Research has been used for isotope separation studies with cathode materials of carbon and magnesium and also to investigate the performance in terms of the rotational velocity attained for different cathode materials. Here, a vacuum arc centrifuge has been operated with an initial filling gas of either argon or hydrogen for pressures ranging from 10 -3 to 10 -1 Pa. The angular velocity ω of the plasma has been determined by cross-correlating the signals from potential probes, and the electron temperature T has been deduced from Langmuir probe data. At high gas pressures and early times during the 14 ms plasma lifetime, high-frequency nonuniformities frequently observed in the vacuum discharge disappear, suggesting that the associated instability is suppressed. Under the same conditions, nonuniformities rotating with much lower angular velocities are observed in the plasma. Temperatures are reduced in the presence of the background gas, and the theoretical figure of merit for separation proportional to ω 2 /T is increased compared to its value in the vacuum discharge for both argon and hydrogen gas fillings

Vacuum-assisted delivery

Science.gov (United States)

... medlineplus.gov/ency/patientinstructions/000514.htm Vacuum-assisted delivery To use the sharing features on this page, ... through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is fully dilated ( ...

Single-step generation of metal-plasma polymer multicore@shell nanoparticles from the gas phase.

Science.gov (United States)

Solař, Pavel; Polonskyi, Oleksandr; Olbricht, Ansgar; Hinz, Alexander; Shelemin, Artem; Kylián, Ondřej; Choukourov, Andrei; Faupel, Franz; Biederman, Hynek

2017-08-17

Nanoparticles composed of multiple silver cores and a plasma polymer shell (multicore@shell) were prepared in a single step with a gas aggregation cluster source operating with Ar/hexamethyldisiloxane mixtures and optionally oxygen. The size distribution of the metal inclusions as well as the chemical composition and the thickness of the shells were found to be controlled by the composition of the working gas mixture. Shell matrices ranging from organosilicon plasma polymer to nearly stoichiometric SiO 2 were obtained. The method allows facile fabrication of multicore@shell nanoparticles with tailored functional properties, as demonstrated here with the optical response.

The TPX vacuum vessel and in-vessel components

International Nuclear Information System (INIS)

Heitzenroeder, P.; Bialek, J.; Ellis, R.; Kessel, C.; Liew, S.

1994-01-01

The Tokamak Physics Experiment (TPX) is a superconducting tokamak with double-null diverters. TPX is designed for 1,000-second discharges with the capability of being upgraded to steady state operation. High neutron yields resulting from the long duration discharges require that special consideration be given to materials and maintainability. A unique feature of the TPX is the use of a low activation, titanium alloy vacuum vessel. Double-wall vessel construction is used since it offers an efficient solution for shielding, bakeout and cooling. Contained within the vacuum vessel are the passive coil system, Plasma Facing Components (PFCs), magnetic diagnostics, and the internal control coils. All PFCs utilize carbon-carbon composites for exposed surfaces

Ultra high vacuum system for Isabelle full cell

International Nuclear Information System (INIS)

Skelton, R.; Briggs, J.; Chou, T.S.; Foerster, C.; Stattel, P.

1979-01-01

A vacuum system consisting of a 40 m long 8.8 cm diameter stainless steel tube, pumped by 7 pumping stations, has been assembled using automatic welding methods. All components have been fired at 950 0 C in a vacuum furnace at a pressure -4 Torr. Each pumping station contains a Ti-sublimator, a 30 liter/s ion pump and an UHV gauge. After assembly, the entire system was baked out at 250 0 C for 24 hours. A pressure -11 Torr was reached after titanium flash. Surface treatment of stainless for 10 -11 Torr operation, bake out and conditioning cycle to read 1 x 10 -11 Torr, and leak checking at low pressures are discussed

Effective electromagnetic operators in light nuclei

International Nuclear Information System (INIS)

Pintar, J.A.

1974-01-01

The effective operator method is used to calculate matrix elements of the magnetic dipole and electric quadrupole operator in the nuclear 1p shell. The calculational obstacles involved in obtaining the many-body model wavefunctions from an exact application of the effective interaction approach are bypassed by using eigenfunctions determined by a shell model phenomenological fit. The effective operators are assumed to be at most two-body. Realistic two-body (correlated) wavefunctions, which are generated by solving the Bethe-Goldstone equation using a modern nuclear potential, are used to determine the matrix elements of the operators. These are then combined with the appropriate angular momentum coefficients and the many-body wavefunctions, and the results compared with the experimental transition rates and moments throughout the shell. The absence of improvement over the results using the bare operators indicates that the effects of channel coupling and core exclusion are insufficient. A detailed analysis of the M1 data is carried out for the low-lying states in 14 N. Using an unmodified operator, the many-body wavefunctions are phenomenologically adjusted to reproduce the experimental results. In addition, an effective interaction is extracted from these wavefunctions. The definite inconsistencies between this analysis and previous shell model results of other au []hors indicate unequivocally that some alteration of the M1 operator is necessary. A two parameter phenomenological operator is constructed using the sum of the orbital g-factors as one of the adjustable parameters. The operator is fit to two pieces of data in 14 N. The moments and transition widths are recalculated, resulting in improved agreement with experiment throughout the shell. (Diss. Abstr. Int., B)

Free vibration analysis of delaminated composite shells using different shell theories

International Nuclear Information System (INIS)

Nanda, Namita; Sahu, S.K.

2012-01-01

Free vibration response of laminated composite shells with delamination is presented using the finite element method based on first order shear deformation theory. The shell theory used is the extension of dynamic, shear deformable theory according to the Sanders' first approximation for doubly curved shells, which can be reduced to Love's and Donnell's theories by means of tracers. An eight-noded C 0 continuity, isoparametric quadrilateral element with five degrees of freedom per node is used in the formulation. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code. The natural frequencies of the delaminated cylindrical (CYL), spherical (SPH) and hyperbolic paraboloid (HYP) shells are determined by using the above mentioned shell theories, namely Sanders', Love's, and Donnell's. The validity of the present approach is established by comparing the authors' results with those available in the literature. Additional studies on free vibration response of CYL, SPH and HYP shells are conducted to assess the effects of delamination size and number of layers considering all three shell theories. It is shown that shell theories according to Sanders and Love always predict practically identical frequencies. Donnell's theory gives reliable results only for shallow shells. Moreover, the natural frequency is found to be very sensitive to delamination size and number of layers in the shell.

TFCX pumped limiter and vacuum pumping system design and analysis

International Nuclear Information System (INIS)

Haines, J.R.

1985-04-01

Impurity control system design and performance studies were performed in support of the Tokamak Fusion Core Experiment (TFCX) pre-conceptual design. Efforts concentrated on pumped limiter and vacuum pumping system design configuration, thermal/mechanical and erosion lifetime performance of the limiter protective surface, and helium ash removal performance. The reference limiter design forms a continuous toroidal belt at the bottom of the device and features a flat surface with a single leading edge. The vacuum pumping system features large vacuum ducts (diameter approximately 1 m) and high-speed, compound cryopumps. Analysis results indicate that the limiter/vacuum pumping system design provides adequate helium ash removal. Erosion, primarily by disruption-induced vaporization and/or melting, limits the protective surface lifetime to about one calendar year or only about 60 full-power hours of operation. In addition to evaluating impurity control system performance for nominal TFCX conditions, these studies attempt to focus on the key plasma physics and engineering design issues that should be addressed in future research and development programs

A comparison between atmospheric/humidity and vacuum cyanoacrylate fuming of latent fingermarks.

Science.gov (United States)

Farrugia, Kevin J; Fraser, Joanna; Friel, Lauren; Adams, Duncan; Attard-Montalto, Nicola; Deacon, Paul

2015-12-01

A number of pseudo-operational trials were set up to compare the atmospheric/humidity and vacuum cyanoacrylate fuming processes on plastic carrier bags. The fuming processes were compared using two-step cyanoacrylate fuming with basic yellow 40 (BY40) staining and a one-step fluorescent cyanoacrylate fuming, Lumicyano 4%. Preliminary work using planted fingermarks and split depletions were performed to identify the optimum vacuum fuming conditions. The first pseudo-operational trial compared the different fuming conditions (atmospheric/humidity vs. vacuum) for the two-step process where an additional 50% more marks were detected with the atmospheric/humidity process. None of the marks by the vacuum process could be observed visually; however, a significant number of marks were detected by fluorescence after BY40 staining. The second trial repeated the same work in trial 1 using the one-step cyanoacrylate process, Lumicyano at a concentration of 4%. Trial 2 provided comparable results to trial 1 and all the items were then re-treated with Lumicyano 4% at atmospheric/humidity conditions before dyeing with BY40 to provide the sequences of process A (Lumicyano 4% atmospheric-Lumicyano 4% atmospheric-BY40) and process B (Lumicyano 4% vacuum-Lumicyano 4% atmospheric-BY40). The number of marks (visual and fluorescent) was counted after each treatment with a substantial increase in the number of detected marks in the second and third treatments of the process. The increased detection rate after the double Lumicyano process was unexpected and may have important implications. Trial 3 was performed to investigate whether the amount of cyanoacrylate and/or fuming time had an impact on the results observed in trial 2 whereas trial 4 assessed if the double process using conventional cyanoacrylate, rather than Lumicyano 4%, provided an increased detection rate. Trials 3 and 4 confirmed that doubling the amount of Lumicyano 4% cyanoacrylate and fuming time produced a lower

Vacuum in the presence of electromagnetic fields and rotating boundaries

International Nuclear Information System (INIS)

Manogue, C.A.

1984-01-01

Two investigations of the properties of the vacuum are made. The first is a reconsideration of the classic Klein paradox, particle creation due to the presence of very strong external electromagnetic potentials. Expectation values of the current, momentum, and number operators, each of which is a measure of particle creation, are calculated for both massive spin zero and massive spin one half fields. The relationship between super-radiance and pair creation is explained. A review of past work by other authors is included and common conceptual errors are pointed out. The second investigation concerns the rotation of the vacuum caused by the rotation of boundaries. Just as the presence of boundaries can create a change in the vacuum expectation value of the energy density (the Casimir effect), the rotation of such boundaries can create changes in the vacuum expectation value of the momentum density. Calculations of the Casimir effect are made for a massless scalar field confined to an infinitely long square box. The change in the vacuum expectation value of the momentum density is calculated if this same box is rotating around its long central axis. In contrast, it is shown that for an infinitely long circular cylinder there is no change in the momentum density

High Charge State Ions Extracted from Metal Plasmas in the Transition Regime from Vacuum Spark to High Current Vacuum Arc

International Nuclear Information System (INIS)

Yushkov, Georgy Yu.; Anders, A.

2008-01-01

Metal ions were extracted from pulsed discharge plasmas operating in the transition region between vacuum spark (transient high voltage of kV) and vacuum arc (arc voltage ∼ 20 V). At a peak current of about 4 kA, and with a pulse duration of 8 (micro)s, we observed mean ion charges states of about 6 for several cathode materials. In the case of platinum, the highest average charge state was 6.74 with ions of charge states as high as 10 present. For gold we found traces of charge state 11, with the highest average charge state of 7.25. At currents higher than 5 kA, non-metallic contaminations started to dominate the ion beam, preventing further enhancement of the metal charge states

Physical states at the tachyonic vacuum of open string field theory

International Nuclear Information System (INIS)

Giusto, S.; Imbimbo, C.

2004-01-01

We illustrate a method for computing the number of physical states of open string theory at the stable tachyonic vacuum in level truncation approximation. The method is based on the analysis of the gauge-fixed open string field theory quadratic action that includes Fadeev-Popov ghost string fields. Computations up to level 9 in the scalar sector are consistent with Sen's conjecture about the absence of physical open string states at the tachyonic vacuum. We also derive a long exact cohomology sequence that relates relative and absolute cohomologies of the BRS operator at the non-perturbative vacuum. We use this exact result in conjunction with our numerical findings to conclude that the higher ghost number non-perturbative BRS cohomologies are non-empty

Calculation of period processing solution syrup in vacuum apparatus

Directory of Open Access Journals (Sweden)

A. A. Slavyanskii

2016-01-01

Full Text Available Important and crucial element in the management of the technological flow of production of sugar product standards is the period of time the enrichment of massecuite, since its neutralization in the process of crystal formation in vacuum apparatus, excess sugar solution. Although currently proposed and implemented in the industry, including as a front-end accompany the process, a number of ways in the real world sugar production in many cases have to resort to the services of an experienced operator. It is obvious that in any case it is necessary to have a surround-dependent glucose solution data on time for the excess sugar solution into the vacuum apparatus. With regard to the period of the enrichment of depleted sucrose solution are entered into this substance excess sucrose solution, it should be noted that this problem is theoretically still insufficiently developed. It is obvious that for practical purposes it is desirable to have a simple and convenient for engineering calculation of sugar processing time dependencies of the specified volume of water from the operating parameters of the process (the required concentration of sucrose, temperature of the solution stirring. The problem is the quantitative analysis of sucrose crystallization in vacuum apparatus, including the timing of enrichment solution to the excess syrup, period of time processing massecuite total this apparatus has been investigated in many works. However, due to its importance to the task of obtaining commercial sugar high standards this issue required further in-depth examination. In the article to support the enrichment process solution sucrose due to neutralize this solvent system in vacuum apparatus, from the standpoint of diffusion theory provides a more reasonable compared to known so far, quantitative analysis of this process. Where as sucrose crystals team are considering a system of balls, uniformly distributed in vacuum apparatus. On the basis of the solution

Running jobs in the vacuum

International Nuclear Information System (INIS)

McNab, A; Stagni, F; Garcia, M Ubeda

2014-01-01

We present a model for the operation of computing nodes at a site using Virtual Machines (VMs), in which VMs are created and contextualized for experiments by the site itself. For the experiment, these VMs appear to be produced spontaneously 'in the vacuum' rather having to ask the site to create each one. This model takes advantage of the existing pilot job frameworks adopted by many experiments. In the Vacuum model, the contextualization process starts a job agent within the VM and real jobs are fetched from the central task queue as normal. An implementation of the Vacuum scheme, Vac, is presented in which a VM factory runs on each physical worker node to create and contextualize its set of VMs. With this system, each node's VM factory can decide which experiments' VMs to run, based on site-wide target shares and on a peer-to-peer protocol in which the site's VM factories query each other to discover which VM types they are running. A property of this system is that there is no gate keeper service, head node, or batch system accepting and then directing jobs to particular worker nodes, avoiding several central points of failure. Finally, we describe tests of the Vac system using jobs from the central LHCb task queue, using the same contextualization procedure for VMs developed by LHCb for Clouds.

Properties of DLC coatings deposited by dc and dc with superimposed pulsed vacuum arc

International Nuclear Information System (INIS)

Zavaleyev, V.; Walkowicz, J.; Aksyonov, D.S.; Luchaninov, A.A.; Reshetnyak, E.N.; Strel'nitskij, V.E.

2014-01-01

Comparative studies of the structure, mechanical and tribological properties of DLC coatings deposited in DC and DC with superimposed high current pulse modes of operation vacuum-arc plasma source with the graphite cathode are presented. Imposition the pulses of high current on DC vacuum-arc discharge allows both increase the deposition rate of DLC coating and reduce the residual compressive stress in the coatings what promotes substantial improvement the adhesion to the substrate. Effect of vacuum arc plasma filtration with Venetian blind filter on the deposition rate and tribological characteristics of the coatings analyzed.

Shell launches its Claus off-gas desulfurization process

Energy Technology Data Exchange (ETDEWEB)

Groenendaal, W; van Meurs, H C.A.

1972-01-01

The Shell Flue Gas Desulfurization (SFGD) Process was developed for removal of sulfur oxides from flue gases originating from oil-fired boilers or furnaces. It can also be used to remove sulfur dioxide from Claus sulfur recovery tail gases if they are combined with boiler/furnace flue gases. For Claus tail gas only, the Shell Claus off-gas desulfurization process was developed. Claus unit operation and desulfurization by low temperature Claus processes and conversion/concentration processes are discussed. The new Shell process consists of a conversion/concentration process involving a reduction section and an amine absorption section. In the reduction section, all sulfur compounds and free sulfur are completely reduced to hydrogen sulfide with hydrogen, or hydrogen plus carbon monoxide, over a cobalt/molybdenum-on-alumina catalyst at a temperature of about 300/sup 0/C. Extensive bench scale studies on the reduction system have been carried out. A life test of more than 4000 hr showed a stable activity of the reduction catalyst, which means that in commercial units, very long catalyst lives can be expected. The commercial feasibility of the reduction section was further demonstrated in the Godorf refinery of Deutsche Shell AG. More than 80 absorption units using alkanolamine (AIDP) solutions have been installed. Bench scale studies of the ADIP absorption units were compared to commercial experience.The total capital investment of the new Shell process is 0.7, 2.0, and 3.2 $ times 10 to the 6th power for 100, 500, and 1000 tons of sulfur/sd capacity Claus units, respectively. The total operating costs for these units are, respectively, 610, 1930 and 3310 $/stream day. The capital investment corresponds to about 75% of the capital investment of the preceding Claus unit.

Composted oyster shell as lime fertilizer is more effective than fresh oyster shell.

Science.gov (United States)

Lee, Young Han; Islam, Shah Md Asraful; Hong, Sun Joo; Cho, Kye Man; Math, Renukaradhya K; Heo, Jae Young; Kim, Hoon; Yun, Han Dae

2010-01-01

Physio-chemical changes in oyster shell were examined, and fresh and composted oyster shell meals were compared as lime fertilizers in soybean cultivation. Structural changes in oyster shell were observed by AFM and FE-SEM. We found that grains of the oyster shell surface became smoother and smaller over time. FT-IR analysis indicated the degradation of a chitin-like compound of oyster shell. In chemical analysis, pH (12.3+/-0.24), electrical conductivity (4.1+/-0.24 dS m(-1)), and alkaline powder (53.3+/-1.12%) were highest in commercial lime. Besides, pH was higher in composted oyster shell meal (9.9+/-0.53) than in fresh oyster shell meal (8.4+/-0.32). The highest organic matter (1.1+/-0.08%), NaCl (0.54+/-0.03%), and moisture (15.1+/-1.95%) contents were found in fresh oyster shell meal. A significant higher yield of soybean (1.33 t ha(-1)) was obtained by applying composted oyster shell meal (a 21% higher yield than with fresh oyster shell meal). Thus composting of oyster shell increases the utility of oyster shell as a liming material for crop cultivation.

Improvement of the long pulse operation of the s-band klystron

Energy Technology Data Exchange (ETDEWEB)

Sakai, T. [Graduate School of Sceince and Technology, Nihon Univ., Funabashi, Chiba (Japan); Sato, I.; Hayakawa, K. [Nihon Univ., Funabashi, Chiba (Japan). Atomic Energy Research Inst

2000-07-01

The long pulse operation of the PV3030 klystron for FEL linac at LEBRA in Nihon University has been improved considerably by the additional vacuum system placed immediately downstream the klystron output rf window. With the new vacuum system, the large conductance has enabled a high vacuum in normal operation and a quick recovery when the dielectric breakdown occurred. A high vacuum near the rf window may be essentially important for a stable operation of the high power klystron with long pulse duration. Now the PV3030 klystron can be operated at the condition of 20 MW x 20 {mu}s x 12.5 Hz. (author)

On the core-mass-shell-luminosity relation for shell-burning stars

International Nuclear Information System (INIS)

Jeffery, C.S.; Saint Andrews Univ.

1988-01-01

Core-mass-shell-luminosity relations for several types of shell-burning star have been calculated using simultaneous differential equations derived from simple homology approximations. The principal objective of obtaining a mass-luminosity relation for helium giants was achieved. This relation gives substantially higher luminosities than the equivalent relation for H-shell stars with core masses greater than 1 solar mass. The algorithm for calculating mass-luminosity relations in this fashion was investigated in detail. Most of the assumptions regarding the physics in the shell do not play a critical role in determining the core-mass-shell-luminosity relation. The behaviour of the core-mass-core-radius relation for a growing degenerate core as a single unique function of mass and growth rate needs to be defined before a single core-mass-shell-luminosity relation for all H-shell stars can be obtained directly from the homology approximations. (author)

Modifications in the vacuum loop of the distillation system - Annex 7; Prilog 7 - Izmene u vakuumskoj grani destilacionog sistema

Energy Technology Data Exchange (ETDEWEB)

Milosevic, D [Institute of Nuclear Sciences Boris Kidric, Reaktor RA, Vinca, Beograd (Serbia and Montenegro)

1964-12-15

The heavy water distillation system is foreseen to operate in a continuous regime during reactor operation. The vacuum loop is designed to achieve absolute pressure of 70 mmHg in the evaporator. Modifications in the vacuum loop of the distillation system were necessary in order to attain good efficiency of the distillation, i.e clean heavy water coolant.

Are vacuum-filtrated reduced graphene oxide membranes symmetric?

KAUST Repository

Tang, Bo; Zhang, Lianbin; Li, Renyuan; Wu, Jinbo; Hedhili, Mohamed Neijib; Wang, Peng

2015-01-01

Graphene or reduced graphene oxide (rGO) membrane-based materials are promising for many advanced applications due to their exceptional properties. One of the most widely used synthesis methods for rGO membranes is vacuum filtration of graphene oxide (GO) on a filter membrane, followed by reduction, which shows great advantages such as operational convenience and good controllability. Despite vacuum-filtrated rGO membranes being widely used in many applications, a fundamental question is overlooked: are the top and bottom surfaces of the membranes formed at the interfaces with air and with the filter membrane respectively symmetric or asymmetric? This work, for the first time, reports the asymmetry of the vacuum-filtrated rGO membranes and discloses the filter membranes’ physical imprint on the bottom surface of the rGO membrane, which takes place when the filter membrane surface pores have similar dimension to GO sheets. This result points out that the asymmetric surface properties should be cautiously taken into consideration while designing the surface-related applications for GO and rGO membranes.

Are vacuum-filtrated reduced graphene oxide membranes symmetric?

KAUST Repository

Tang, Bo

2015-12-02

Graphene or reduced graphene oxide (rGO) membrane-based materials are promising for many advanced applications due to their exceptional properties. One of the most widely used synthesis methods for rGO membranes is vacuum filtration of graphene oxide (GO) on a filter membrane, followed by reduction, which shows great advantages such as operational convenience and good controllability. Despite vacuum-filtrated rGO membranes being widely used in many applications, a fundamental question is overlooked: are the top and bottom surfaces of the membranes formed at the interfaces with air and with the filter membrane respectively symmetric or asymmetric? This work, for the first time, reports the asymmetry of the vacuum-filtrated rGO membranes and discloses the filter membranes’ physical imprint on the bottom surface of the rGO membrane, which takes place when the filter membrane surface pores have similar dimension to GO sheets. This result points out that the asymmetric surface properties should be cautiously taken into consideration while designing the surface-related applications for GO and rGO membranes.

First Half Of The ATLAS Vacuum Chamber Arrives

CERN Multimedia

2001-01-01

The ATLAS detector, built to observe and record the products of head-on collisions of protons in the Large Hadron Collider, is one of the largest and most elaborate particle physics experiments ever designed. It is the product of a world-wide effort by over 1800 scientists from more than 150 laboratories and institutions in 34 countries. With the detector due to begin operation in 2005, its various components have started to arrive from their manufacturers around the world, the most recent being the first of the two vacuum chambers for the two end cap toroid magnets. As it is too big to transport all at once it is comes in two halves. Each half of the vacuum chamber weighs 40 tonnes and is about 11x5.5x5 cubic meters in size. The huge 500 cubic meter vacuum vessles are an in kind contribution to ATLAS from NIKHEF (the Netherlands Institute for High Energy Physics) following a design by the Rutherford Appleton Laboratory in the UK. The chamber was built and delivered by the Royal Schelde Exotech shipyards i...

Calibration apparatus for precise barometers and vacuum gauges

International Nuclear Information System (INIS)

Woo, S.Y.; Choi, I.M.; Lee, Y.J.; Hong, S.S.; Chung, K.H.

2004-01-01

In order to calibrate highly accurate absolute pressure gauges, such as barometers and vacuum gauges, laser, or ultrasonic mercury manometers have been used. However, the complexity and cost of manometers have greatly reduced the use of this method in most calibration laboratories. As a substitute, a gas-operated pressure balance is used to calibrate precise gauges. In such cases, many commercially available pressure balances are unsuitable because the necessary exposure of the piston, cylinder, and masses to the atmosphere causes contamination problems and allows dust particles into the gap between the piston and cylinder. In this article, a weight-loading device is described that allows masses to be changed in situ without breaking the vacuum. This device makes it possible to add or remove weights easily during the calibration, thereby greatly reducing the time between observations. Using this device, we efficiently calibrated a precise quartz resonance barometer (Paroscientific, model 760-16B) over a pressure range of 940-1050 h Pa and a precise vacuum gauge (MKS, CDG 100 Torr) over a pressure range of 0-100 h Pa

Variation in Orthologous Shell-Forming Proteins Contribute to Molluscan Shell Diversity.

Science.gov (United States)

Jackson, Daniel J; Reim, Laurin; Randow, Clemens; Cerveau, Nicolas; Degnan, Bernard M; Fleck, Claudia

2017-11-01

Despite the evolutionary success and ancient heritage of the molluscan shell, little is known about the molecular details of its formation, evolutionary origins, or the interactions between the material properties of the shell and its organic constituents. In contrast to this dearth of information, a growing collection of molluscan shell-forming proteomes and transcriptomes suggest they are comprised of both deeply conserved, and lineage specific elements. Analyses of these sequence data sets have suggested that mechanisms such as exon shuffling, gene co-option, and gene family expansion facilitated the rapid evolution of shell-forming proteomes and supported the diversification of this phylum specific structure. In order to further investigate and test these ideas we have examined the molecular features and spatial expression patterns of two shell-forming genes (Lustrin and ML1A2) and coupled these observations with materials properties measurements of shells from a group of closely related gastropods (abalone). We find that the prominent "GS" domain of Lustrin, a domain believed to confer elastomeric properties to the shell, varies significantly in length between the species we investigated. Furthermore, the spatial expression patterns of Lustrin and ML1A2 also vary significantly between species, suggesting that both protein architecture, and the regulation of spatial gene expression patterns, are important drivers of molluscan shell evolution. Variation in these molecular features might relate to certain materials properties of the shells of these species. These insights reveal an important and underappreciated source of variation within shell-forming proteomes that must contribute to the diversity of molluscan shell phenotypes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Analysis of an innovative solar water desalination system using gravity induced vacuum

International Nuclear Information System (INIS)

Ayhan, T.; Al-Madani, H.

2007-01-01

This study presents the theoretical analysis, design and appropriate models of a new desalination system using gravity induced vacuum. The system utilizes natural means (gravity and atmospheric pressure) to create a vacuum under which water can be rapidly evaporated at much lower temperatures with less energy than conventional techniques. This technique is developed to overcome water storage, in the areas where good solar radiation (or waste heat sources) and sea water (or waste water sources). The developed system consists of an evaporator connected to condenser by means of a vacuum tank. The vapour produced in the evaporator is driven to condenser through the vacuum tank, where it condenses and collected as a product. Vacuum equivalent to 7 kPa (abs) or less can be created depending on ambient temperature of Bahrain climatic conditions. The effect of various operating conditions, namely water levels in condensation and evaporating columns on the system performance were studied. The theoretical analysis and preliminary experimental results show that the performance of this system depends on the condensation temperature

State-of-the-art of recycling e-wastes by vacuum metallurgy separation.

Science.gov (United States)

Zhan, Lu; Xu, Zhenming

2014-12-16

In recent era, more and more electric and electronic equipment wastes (e-wastes) are generated that contain both toxic and valuable materials in them. Most studies focus on the extraction of valuable metals like Au, Ag from e-wastes. However, the recycling of metals such as Pb, Cd, Zn, and organics has not attracted enough attentions. Vacuum metallurgy separation (VMS) processes can reduce pollution significantly using vacuum technique. It can effectively recycle heavy metals and organics from e-wastes in an environmentally friendly way, which is beneficial for both preventing the heavy metal contaminations and the sustainable development of resources. VMS can be classified into several methods, such as vacuum evaporation, vacuum carbon reduction and vacuum pyrolysis. This paper respectively reviews the state-of-art of these methods applied to recycling heavy metals and organics from several kinds of e-wastes. The method principle, equipment used, separating process, optimized operating parameters and recycling mechanism of each case are illustrated in details. The perspectives on the further development of e-wastes recycling by VMS are also presented.

Design and Construction of the NSTX Bakeout, Cooling and Vacuum Systems

International Nuclear Information System (INIS)

Dudek, L.E.; Kalish, M.; Gernhardt, R.; Parsells, R.F.; Blanchard, W.

1999-01-01

This paper will describe the design, construction and initial operation of the NSTX bakeout, water cooling and vacuum systems. The bakeout system is designed for two modes of operation. The first mode allows heating of the first wall components to 350 degrees C while the external vessel is cooled to 150 degrees C. The second mode cools the first wall to 150 degrees C and the external vessel to 50 degrees C. The system uses a low viscosity heat transfer oil which is capable of high temperature low pressure operation. The NSTX Torus Vacuum Pumping System (TVPS) is designed to achieve a base pressure of approximately 1x10 (superscript -8) Torr and to evacuate the plasma fuel gas loads in less than 5 minutes between discharges. The vacuum pumping system is capable of a pumping speed of approximately 3400 l/s for deuterium. The hardware consists of two turbo molecular pumps (TMPs) and a mechanical pump set consisting of a mechanical and a Roots blower pump. A PLC is used as the control system to provide remote monitoring, control and software interlock capability. The NSTX cooling water provides chilled, de ionized water for heat removal in the TF, OH and PF, power supplies, bus bar systems, and various diagnostics. The system provides flow monitoring via a PLC to prevent damage due to loss of flow

JT-60SA vacuum vessel manufacturing and assembly

Energy Technology Data Exchange (ETDEWEB)

Masaki, Kei, E-mail: masaki.kei@jaea.go.jp [Japan Atomic Energy Agency, Naka, Ibaraki-ken 311-0193 (Japan); Shibama, Yusuke K.; Sakurai, Shinji; Shibanuma, Kiyoshi; Sakasai, Akira [Japan Atomic Energy Agency, Naka, Ibaraki-ken 311-0193 (Japan)

2012-08-15

Highlights: Black-Right-Pointing-Pointer The design of the JT-60SA vacuum vessel body was completed with the demonstration of manufacturing procedure by the mock-up fabrication of the 20 Degree-Sign upper half of VV. Black-Right-Pointing-Pointer The actual VV manufacturing has started since November 2009. Black-Right-Pointing-Pointer The first product of the VV 40 Degree-Sign sector was completed in May 2011. Black-Right-Pointing-Pointer A basic VV assembly scenario and procedure were studied to complete the 360 Degree-Sign VV including positioning method and joint welding. - Abstract: The JT-60SA vacuum vessel (VV) has a D-shaped poloidal cross section and a toroidal configuration with 10 Degree-Sign segmented facets. A double wall structure is adopted to ensure high rigidity at operational load and high toroidal one-turn resistance. The material is 316L stainless steel with low cobalt content (<0.05%). The design temperatures of the VV at plasma operation and baking are 50 Degree-Sign C and 200 Degree-Sign C, respectively. In the double wall, boric-acid water is circulated at plasma operation to reduce the nuclear heating of the superconducting magnets. For baking, nitrogen gas is circulated in the double wall after draining of the boric-acid water. The manufacturing of the VV started in November 2009 after a fundamental welding R and D and a trial manufacturing of 20 Degree-Sign upper half mock-up. The manufacturing of the first VV 40 Degree-Sign sector was completed in May 2011. A basic concept and required jigs of the VV assembly were studied. This paper describes the design and manufacturing of the vacuum vessel. A plan of VV assembly in torus hall is also presented.

Conditioning of the vacuum chamber of the Tokamak Novillo

International Nuclear Information System (INIS)

Valencia A, R.; Lopez C, R.; Melendez L, L.; Chavez A, E.; Colunga S, S.; Gaytan G, E.

1992-03-01

The obtained experimental results of the implementation of two techniques of present time for the conditioning of the internal wall of the chamber of discharges of the Tokamak Novillo are presented, which has been designed, built and put in operation in the Laboratory of Plasma Physics of the National Institute of Nuclear Research (ININ). These techniques are: the vacuum baking and the low energy pulsed discharges, which were applied after having reached an initial pressure of the order of 10 -7 Torr. with a system of turbomolecular pumping previous preparation of surfaces and vacuum seals. The analysis of residual gases was carried out with a mass spectrometer before and after conditioning. The obtained results show that the vacuum baking it was of great effectiveness to reduce the value of the initial pressure in short time, in more of a magnitude order and the low energy discharges reduced the oxygen at worthless levels with regard to the initial values. (Author)

Field installed brazed thermocouple feedthroughs for high vacuum experiments

International Nuclear Information System (INIS)

Anderson, P.; Messick, C.

1983-01-01

In order to reduce the occurrence of vacuum leaks and to increase the availability of the DIII vacuum vessel for experimental operation, effort was applied to developing a vacuum-tight brazed feedthrough system for sheathed thermocouples, stainless steel sheathed conductor cables and tubes for cooling fluids. This brazed technique is a replacement for elastomer ''O'' ring sealed feedthroughs that have proven vulnerable to leaks caused by thermal cycling, etc. To date, about 200 feedthroughs have been used. Up to 91 were grouped on a single conflat flange mounted in a bulkhead connector configuration which facilitates installation and removal. Investigation was required to select a suitable braze alloy, flux and installation procedure. Braze alloy selection was challenging since the alloy was required to have: 1) Melting temperature in excess of the 250 0 C (482 0 F) bakeout temperature. 2) No high vapor pressure elements. 3) Good wetting properties when used in air with acceptable flux. 4) Good wettability to 300 series stainless steel and inconel

Fabrication of a full-size mock-up for inboard 10o section of ITER vacuum vessel thermal shield

International Nuclear Information System (INIS)

Chung, W.; Nam, K.; Noh, C.H.; Kang, D.K.; Kang, S.M.; Oh, Y.G.; Choi, S.W.; Kang, S.H.; Utin, Y.; Ioki, K.; Her, N.; Yu, J.

2011-01-01

A full-scale mock-up of VVTS inboard section was made in order to validate its manufacturing processes before manufacturing the vacuum vessel thermal shield (VVTS) for ITER tokamak. VVTS inboard 10 o section consists of 20 mm shells on which cooling tubes are welded and flange joints that connect adjacent thermal shield sectors. The whole VVTS inboard is divided into two by bisectional flange joint located at the center. All the manufacturing processes except silver coating were tested and verified in the fabrication of mock-up. For the forming and the welding, pre-qualification tests were conducted to find proper process conditions. Shell thickness change was measured after bending, forming and buffing processes. Shell distortion was adjusted after the welding. Welding was validated by non-destructive examination. Bisectional flange joint was successfully assembled by inserting pins and tightening with bolt/nut. Bolt hole margin of 2 mm for sector flange was revealed to be sufficient by successful sector assembly of upper and lower parts of mock-up. Handling jig was found to be essential because the inboard section was flexible. Dimensional inspection of the fabricated mock-up was performed with a 3D laser scanner.

Off-shell CHY amplitudes

Energy Technology Data Exchange (ETDEWEB)

Lam, C.S., E-mail: Lam@physics.mcgill.ca [Department of Physics, McGill University, Montreal, Q.C., H3A 2T8 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Yao, York-Peng, E-mail: yyao@umich.edu [Department of Physics, The University of Michigan Ann Arbor, MI 48109 (United States)

2016-06-15

The Cachazo–He–Yuan (CHY) formula for on-shell scattering amplitudes is extended off-shell. The off-shell amplitudes (amputated Green's functions) are Möbius invariant, and have the same momentum poles as the on-shell amplitudes. The working principles which drive the modifications to the scattering equations are mainly Möbius covariance and energy momentum conservation in off-shell kinematics. The same technique is also used to obtain off-shell massive scalars. A simple off-shell extension of the CHY gauge formula which is Möbius invariant is proposed, but its true nature awaits further study.

HV Test of the CTS Edgeless Silicon Detector in Vacuum and Close to a Grounded Plate

CERN Document Server

Eremin, Vladimir; Ruggiero, Gennaro

2007-01-01

The TOTEM Roman Pot Silicon sensors will be operated in vacuum to minimise the mechanical stress of the thin metal window which separates the detector package from the ultra high vacuum of the beam. To approach the beam axis as close as possible the detectors will be mounted with their edge at a distance of the order 100 - 200 um from the thin metal window. As the detectors will be run in overdepletion mode to allow the full charge collection within the shaping time of the readout electronics, there will be a potential drop of more than 100 V across their edge. Moreover this potential drop might need to be further increased with the accumulated radiation dose. The main goals of the tests described in this note are: - Characterisation of the voltage-current characteristics when the detector edge is in the direct vicinity of a grounded metal plate which simulates the above mentioned vacuum window; - Demonstration of the detector operation in vacuum at different pressures.

Open loop, auto reversing liquid nitrogen circulation thermal system for thermo vacuum chamber

International Nuclear Information System (INIS)

Naidu, M C A; Nolakha, Dinesh; Saharkar, B S; Kavani, K M; Patel, D R

2012-01-01

In a thermo vacuum chamber, attaining and controlling low and high temperatures (-100 Deg. C to +120 Deg. C) is a very important task. This paper describes the development of 'Open loop, auto reversing liquid nitrogen based thermal system'. System specifications, features, open loop auto reversing system, liquid nitrogen flow paths etc. are discussed in this paper. This thermal system consists of solenoid operated cryogenic valves, double embossed thermal plate (shroud), heating elements, temperature sensors and PLC. Bulky items like blowers, heating chambers, liquid nitrogen injection chambers, huge pipe lines and valves were not used. This entire thermal system is very simple to operate and PLC based, fully auto system with auto tuned to given set temperatures. This system requires a very nominal amount of liquid nitrogen (approx. 80 liters / hour) while conducting thermo vacuum tests. This system was integrated to 1.2m dia thermo vacuum chamber, as a part of its augmentation, to conduct extreme temperature cycling tests on passive antenna reflectors of satellites.

Vacuum considerations: summary

International Nuclear Information System (INIS)

Blechschmidt, D.; Halama, H.J.

1978-01-01

A summary is given of the efforts of a vacuum systems study group of the workshop on a Heavy Ion Demonstration Experiment (HIDE) for heavy ion fusion. An inadequate knowledge of cross-sections prevents a more concrete vacuum system design. Experiments leading to trustworthy numbers for charge exchange, stripping and capture cross-sections are badly needed and should start as soon as possible. In linacs, beam loss will be almost directly proportional to the pressure inside the tanks. The tanks should, therefore, be built in such a way that they can be baked-out in situ to improve their vacuum, especially if the cross-sections turn out to be higher than anticipated. Using standard UHV techniques and existing pumps, an even lower pressure can be achieved. The vacuum system design for circular machines will be very difficult, and in some cases, beyond the present state-of-the-art

A review of the use of Al-alloy vacuum components for operation at 10-13 Torr

Science.gov (United States)

Ishimaru, Hajime

1990-02-01

An extremely high vacuum (XHV) chamber was fabricated and tested. The vacuum chamber was made of special surface finished (EX-process) aluminum alloy in oxygen and argon atmosphere. The chamber was assembled using TIG welding in an argon atmosphere and by electron beam welding. The system was evacuated with a turbo-backed 300 l/s turbomolecular pump separated from the main chamber using a right angle valve. The liquid nitrogen shroud is installed inside the main vacuum chamber. The XHV is maintained by two 300 l/s sputter ion pumps and a titanium sublimation pump with a liquid nitrogen shroud. These pumps are also made of aluminum alloys. An ultimate pressure of 3×10-13 Torr was measured with a point collector gauge with a spherical anode mounted on an Al-flange. Residual gas analysis in the order 10-13 Torr was performed by a newly developed Q-mass filter. To suppress outgassing from the quadrupole electrode, the ion source is mounted on an Al-flange separated from the quadrupole electrode.

ECO-TECHNIQUE OF SEWER RENOVATION USING COMPOSITE SHELLS: STRUCTURAL ANALYSIS

Directory of Open Access Journals (Sweden)

B. Attaf

2015-07-01

Full Text Available An eco-technical renovation of the sewage system is developed in this paper; this technique involves incorporating into the existing sewer a series of jointed prefabricated sandwich or composite shells. The purpose of his study is to determine the structural shell deflection, the high displacement areas and to validate the non-failure criterion for each ply constituting the inner and outer laminate facings. The numerical results were obtained at low cost by using the finite element method. Studies have focused on structural analysis of a typical shell unit with an ovoid form (egg-shaped section when it is subjected, during annular space filling operation, to pressure forces generated by wet concrete. To ensure the safety of the composite shell structure, Tsai-Hill criterion function is applied and results are presented for the most stressed plies

The influence of hydrogen on the fatigue life of metallic leaf spring components in a vacuum environment

NARCIS (Netherlands)

Kouters, M.H.M.; Slot, H.M.; Zwieten, W. van; Veer, J. van der

2014-01-01

Hydrogen is used as a process gas in vacuum environments for semiconductor manufacturing equipment. If hydrogen dissolves in metallic components during operation it can result in hydrogen embrittlement. In order to assess if hydrogen embrittlement occurs in such a vacuum environment a special

Design and R and D for the ITER vacuum vessel

International Nuclear Information System (INIS)

Ioki, K.; Johnson, G.; Onozuka, M.; Sannazzaro, G.; Utin, Y.; Iizuka, T.; Parker, R.; Koizumi, K.; Kuzmin, E.; Maisonnier, D.; Nelson, B.

1998-01-01

The current design and key R and D results for the Vacuum Vessel (VV) for the International Thermonuclear Experimental Reactor (ITER) are presented. During the past two years the basic VV design has remained unchanged. Additional details have been defined in key areas and recent R and D results have indicated where further improvements can be made. R and D results have also confirmed the feasibility of important aspects of the design such as limiting weld distortions to acceptable levels and achieving required tolerances with a large welded structure. Recent design progress includes the development of a structural design strategy for the VV, modification of the inboard structure, employment of ferromagnetic material between the VV shells, and confirmation of the cooling characteristics for the VV. This report presents the current design and how it has been affected by R and D results. (authors)

Design and R and D for the ITER vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Ioki, K.; Johnson, G.; Onozuka, M.; Sannazzaro, G.; Utin, Y.; Iizuka, T.; Parker, R. [ITER Joint Work Site, Garching (Germany); Koizumi, K. [Japan Atomic Energy Research Inst., Naka (Japan); Kuzmin, E. [Efremov Insitute, Saint Petersburg (Russian Federation); Maisonnier, D. [NET Team, Garching (Germany); Nelson, B. [Oak Ridge National Lab., TN (United States)

1998-07-01

The current design and key R and D results for the Vacuum Vessel (VV) for the International Thermonuclear Experimental Reactor (ITER) are presented. During the past two years the basic VV design has remained unchanged. Additional details have been defined in key areas and recent R and D results have indicated where further improvements can be made. R and D results have also confirmed the feasibility of important aspects of the design such as limiting weld distortions to acceptable levels and achieving required tolerances with a large welded structure. Recent design progress includes the development of a structural design strategy for the VV, modification of the inboard structure, employment of ferromagnetic material between the VV shells, and confirmation of the cooling characteristics for the VV. This report presents the current design and how it has been affected by R and D results. (authors)

Modern vacuum physics

CERN Document Server

Chambers, Austin

2005-01-01

Modern Vacuum Physics presents the principles and practices of vacuum science and technology along with a number of applications in research and industrial production. The first half of the book builds a foundation in gases and vapors under rarefied conditions, The second half presents examples of the analysis of representative systems and describes some of the exciting developments in which vacuum plays an important role. The final chapter addresses practical matters, such as materials, components, and leak detection. Throughout the book, the author''s explanations are presented in terms of first principles and basic physics, augmented by illustrative worked examples and numerous figures.

Gravitation and vacuum field

International Nuclear Information System (INIS)

Tevikyan, R.V.

1986-01-01

This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E → ∞. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory

Surge-damping vacuum valve

International Nuclear Information System (INIS)

Bullock, J.C.; Kelley, B.E.

1977-01-01

A valve for damping out flow surges in a vacuum system is described. The surge-damping mechanism consists of a slotted, spring-loaded disk adjacent to the valve's vacuum port (the flow passage to the vacuum roughing pump). Under flow surge conditions, the differential pressure forces the disk into a sealing engagement with the vacuum port, thereby restricting the gas flow path to narrow slots in the disk's periphery. The increased flow damps out the flow surge. When pressure is equalized on both sides of the valve, the spring load moves the disk away from the port to restore full flow conductance through the valve

Design package for vacuum wand for fuel retrieval system

International Nuclear Information System (INIS)

ROACH, H.L.

1999-01-01

This is a design package that contains the details for the design, fabrication, and testing of a vacuum wand that will pick up sludge and corrosion products generated during fuel assembly handling operations at K-Basin. This document contains requirements, development design information, design calculations, tests, and test reports

Comparison of vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification systems.

Science.gov (United States)

Han, Young Keun; Miller, Kevin M

2009-08-01

To compare vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification machines. Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA. The vacuum rise time under normal and enhanced aspiration modes, vacuum limit accuracy, and occlusion break surge of the Infiniti Vision System, Stellaris Vision Enhancement System, and WhiteStar Signature Phacoemulsification System were tested. Vacuum rise time and limit accuracy were measured at limit settings of 400 mm Hg and 600 mm Hg. Surge area was recorded at vacuum limit settings of 200 mm Hg, 300 mm Hg, 400 mm Hg, and 500 mm Hg. The Infiniti had the fastest vacuum rise times under normal and enhanced aspiration modes. At 4 seconds, the vacuum limit accuracy was greatest with the Infiniti at the 400 mm Hg limit and the Signature at the 600 mm Hg limit. The Stellaris did not reach either vacuum target. The Infiniti performed better than the other 2 machines during testing of occlusion break surge at all vacuum limit settings above 200 mm Hg. Under controlled laboratory test conditions, the Infiniti had the fastest vacuum rise time, greatest vacuum limit accuracy at 400 mm Hg, and least occlusion break surge. These results can be explained by the lower compliance of the Infiniti system.

APS storage ring vacuum system performance

International Nuclear Information System (INIS)

Noonan, J.R.; Gagliano, J.; Goeppner, G.A.

1997-01-01

The Advanced Photon Source (APS) storage ring was designed to operated with 7-GeV, 100-mA positron beam with lifetimes > 20 hours. The lifetime is limited by residual gas scattering and Touschek scattering at this time. Photon-stimulated desorption and microwave power in the rf cavities are the main gas loads. Comparison of actual system gas loads and design calculations will be given. In addition, several special features of the storage ring vacuum system will be presented

Hawking from Catalan

Science.gov (United States)

Fitzpatrick, A. Liam; Kaplan, Jared; Walters, Matthew T.; Wang, Junpu

2016-05-01

The Virasoro algebra determines all `graviton' matrix elements in AdS3/CFT2. We study the explicit exchange of any number of Virasoro gravitons between heavy and light CFT2 operators at large central charge. These graviton exchanges can be written in terms of new on-shell tree diagrams, organized in a perturbative expansion in h H /c, the heavy operator dimension divided by the central charge. The Virasoro vacuum conformal block, which is the sum of all the tree diagrams, obeys a differential recursion relation generalizing that of the Catalan numbers. We use this recursion relation to sum the on-shell diagrams to all orders, computing the Virasoro vacuum block. Extrapolating to large h H /c determines the Hawking temperature of a BTZ black hole in dual AdS3 theories.

The baking analysis for vacuum vessel and plasma facing components of the KSTAR tokamak

International Nuclear Information System (INIS)

Lee, K. H.; Woo, H. K.; Im, K. H.; Cho, S. Y.; Kim, J. B.

2000-01-01

The base pressure of vacuum vessel of the KSTAR (Korea Superconducting Tokamak Advanced Research) Tokamak is to be a ultra high vacuum, 10 -6 ∼10 -7 Pa, to produce clean plasma with low impurity containments. For this purpose, the KSTAR vacuum vessel and plasma facing components need to be baked up to at least 250 .deg. C, 350 .deg. C respectively, within 24 hours by hot nitrogen gas from a separate baking/cooling line system to remove impurities from the plasma-material interaction surfaces before plasma operation. Here by applying the implicit numerical method to the heat balance equations of the system, overall temperature distributions of the KSTAR vacuum vessel and plasma facing components are obtained during the whole baking process. The model for 2-dimensional baking analysis are segmented into 9 imaginary sectors corresponding to each plasma facing component and has up-down symmetry. Under the resulting combined loads including dead weight, baking gas pressure, vacuum pressure and thermal loads, thermal stresses in the vacuum vessel during bakeout are calculated by using the ANSYS code. It is found that the vacuum vessel and its supports are structurally rigid based on the thermal stress analyses

The baking analysis for vacuum vessel and plasma facing components of the KSTAR tokamak

Energy Technology Data Exchange (ETDEWEB)

Lee, K. H.; Woo, H. K. [Chungnam National Univ., Taejon (Korea, Republic of); Im, K. H.; Cho, S. Y. [korea Basic Science Institute, Taejon (Korea, Republic of); Kim, J. B. [Hyundai Heavy Industries Co., Ltd., Ulsan (Korea, Republic of)

2000-07-01

The base pressure of vacuum vessel of the KSTAR (Korea Superconducting Tokamak Advanced Research) Tokamak is to be a ultra high vacuum, 10{sup -6}{approx}10{sup -7}Pa, to produce clean plasma with low impurity containments. For this purpose, the KSTAR vacuum vessel and plasma facing components need to be baked up to at least 250 .deg. C, 350 .deg. C respectively, within 24 hours by hot nitrogen gas from a separate baking/cooling line system to remove impurities from the plasma-material interaction surfaces before plasma operation. Here by applying the implicit numerical method to the heat balance equations of the system, overall temperature distributions of the KSTAR vacuum vessel and plasma facing components are obtained during the whole baking process. The model for 2-dimensional baking analysis are segmented into 9 imaginary sectors corresponding to each plasma facing component and has up-down symmetry. Under the resulting combined loads including dead weight, baking gas pressure, vacuum pressure and thermal loads, thermal stresses in the vacuum vessel during bakeout are calculated by using the ANSYS code. It is found that the vacuum vessel and its supports are structurally rigid based on the thermal stress analyses.

Vacuum type D initial data

Science.gov (United States)

García-Parrado Gómez-Lobo, Alfonso

2016-09-01

A vacuum type D initial data set is a vacuum initial data set of the Einstein field equations whose data development contains a region where the space–time is of Petrov type D. In this paper we give a systematic characterisation of a vacuum type D initial data set. By systematic we mean that the only quantities involved are those appearing in the vacuum constraints, namely the first fundamental form (Riemannian metric) and the second fundamental form. Our characterisation is a set of conditions consisting of the vacuum constraints and some additional differential equations for the first and second fundamental forms These conditions can be regarded as a system of partial differential equations on a Riemannian manifold and the solutions of the system contain all possible regular vacuum type D initial data sets. As an application we particularise our conditions for the case of vacuum data whose data development is a subset of the Kerr solution. This has applications in the formulation of the nonlinear stability problem of the Kerr black hole.

Vacuum pumping concepts for ETF

International Nuclear Information System (INIS)

Homeyer, W.G.

1980-09-01

The Engineering Test Facility (ETF) poses unique vacuum pumping requirements due to its large size and long burn characteristics. These requirements include torus vacuum pumping initially and between burns and pumping of neutralized gas from divertor collector chambers. It was found that the requirements could be met by compound cryopumps in which molecular sieve 5A is used as the cryosorbent. The pumps, ducts, and vacuum valves required are large but fit with other ETF components and do not require major advances in vacuum pumping technology. Several additional design, analytical, and experimental studies were identified as needed to optimize designs and provide better design definition for the ETF vacuum pumping systems

Single-shell tank interim stabilization project plan

Energy Technology Data Exchange (ETDEWEB)

Ross, W.E.

1998-05-11

This project plan establishes the management framework for conduct of the TWRS Single-Shell Tank Interim Stabilization completion program. Specifically, this plan defines the mission needs and requirements; technical objectives and approach; organizational structure, roles, responsibilities, and interfaces; and operational methods. This plan serves as the project executional baseline.

Semi-automated high-efficiency reflectivity chamber for vacuum UV measurements

Science.gov (United States)

Wiley, James; Fleming, Brian; Renninger, Nicholas; Egan, Arika

2017-08-01

This paper presents the design and theory of operation for a semi-automated reflectivity chamber for ultraviolet optimized optics. A graphical user interface designed in LabVIEW controls the stages, interfaces with the detector system, takes semi-autonomous measurements, and monitors the system in case of error. Samples and an optical photodiode sit on an optics plate mounted to a rotation stage in the middle of the vacuum chamber. The optics plate rotates the samples and diode between an incident and reflected position to measure the absolute reflectivity of the samples at wavelengths limited by the monochromator operational bandpass of 70 nm to 550 nm. A collimating parabolic mirror on a fine steering tip-tilt motor enables beam steering for detector peak-ups. This chamber is designed to take measurements rapidly and with minimal oversight, increasing lab efficiency for high cadence and high accuracy vacuum UV reflectivity measurements.

Single-shell tank retrieval program mission analysis report

Energy Technology Data Exchange (ETDEWEB)

Stokes, W.J.

1998-08-11

This Mission Analysis Report was prepared to provide the foundation for the Single-Shell Tank (SST) Retrieval Program, a new program responsible for waste removal for the SSTS. The SST Retrieval Program is integrated with other Tank Waste Remediation System activities that provide the management, technical, and operations elements associated with planning and execution of SST and SST Farm retrieval and closure. This Mission Analysis Report provides the basis and strategy for developing a program plan for SST retrieval. This Mission Analysis Report responds to a US Department of Energy request for an alternative single-shell tank retrieval approach (Taylor 1997).

Single-shell tank retrieval program mission analysis report

International Nuclear Information System (INIS)

Stokes, W.J.

1998-01-01

This Mission Analysis Report was prepared to provide the foundation for the Single-Shell Tank (SST) Retrieval Program, a new program responsible for waste removal for the SSTS. The SST Retrieval Program is integrated with other Tank Waste Remediation System activities that provide the management, technical, and operations elements associated with planning and execution of SST and SST Farm retrieval and closure. This Mission Analysis Report provides the basis and strategy for developing a program plan for SST retrieval. This Mission Analysis Report responds to a US Department of Energy request for an alternative single-shell tank retrieval approach (Taylor 1997)

Dossier Shell Eco-Marathon; Dossier Shell Eco-Marathon

Energy Technology Data Exchange (ETDEWEB)

Matla, P.

2012-05-15

Three articles address subjects concerning the annual race with highly energy efficient cars: the Shell Eco-Marathon. [Dutch] In 3 artikelen wordt aandacht besteed aan de ontwerpen voor de jaarlijkse race met superzuinige auto's, de Shell Eco-Marathon.

Dominant thermogravimetric signatures of lignin in cashew shell as compared to cashew shell cake.

Science.gov (United States)

Gangil, Sandip

2014-03-01

Dominant thermogravimetric signatures related to lignin were observed in cashew shell as compared to these signatures in cashew shell cake. The phenomenon of weakening of lignin from cashew shell to cashew shell cake was explained on the basis of changes in the activation energies. The pertinent temperature regimes responsible for the release of different constituents of both the bio-materials were identified and compared. The activation energies of cashew shell and cashew shell cake were compared using Kissinger-Akahira-Sunose method. Thermogravimetric profiling of cashew shell and cashew shell cake indicated that these were different kinds of bio-materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

LAr calorimeter for SCC with a common vacuum bulkhead---a concept to improve hermeticity

International Nuclear Information System (INIS)

Pope, W.L.; Watt, R.D.

1989-11-01

A new concept for a Barrel/Endcap LAr Calorimeter (LAC) is described in which the Barrel and Endcaps are in separate vacuum enclosures but share a common vacuum bulkhead (CVB). We explore 2 possible bulkhead construction types; welded plate sandwich panels, and brazed sandwich panels in which the core is an isotropic cellular solid--foamed aluminum. Gas lines and electric cables from he innermost Drift Chamber pass through radial holes in the core of the sandwich bulkhead. The CVB concept offers the potential to obtain a more hermetic calorimeter with significantly reduced dead material and/or space in the interface region common to conventional design LAr detectors for the SSC with Endcap features. To utilize a common additional steps to remove the Drift Chamber, a large increase in Endcap standby heat leak, and perhaps, new cryogenic safety issues. We find that significant amount of dead mass can be removed from critical regions of the vacuum shells when compared to a promising SSC LAC reference design. It is also shown that the increased standby heat leak of this concept can be easily removed by existing cooling capacity in another large LAr calorimeter. It is further shown that shut-downs need not be appreciably longer. Finally, it is argued that cryogen spill hazards can be avoided if the Endcap's LAr is removed during Drift chamber maintenance shutdowns, and that cryogenic safety is not compromised

The AGS Booster vacuum systems

International Nuclear Information System (INIS)

Hseuh, H.C.

1989-01-01

The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of low 10 -11 mbar is required to minimize beam loss of the partially stripped heavy ions. To remove contaminants and to reduce outgassing, the vacuum chambers and the components located in them will be chemically cleaned, vacuum fired, baked then treated with nitric oxide. The vacuum sector will be insitu baked to a minimum of 200 degree C and pumped by the combination of sputter ion pumps and titanium sublimation pumps. This paper describes the design and the processing of this ultra high vacuum system, and the performance of some half-cell vacuum chambers. 9 refs., 7 figs

Simple method for evaluating Goldstone diagrams in an angular momentum coupled representation