WorldWideScience

Sample records for high vacuum conditions

  1. Ultra-High Speed Visualization of the Flashing Instability in Micron Size Nozzles under Vacuum Conditions

    KAUST Repository

    Alghamdi, Tariq A.

    2017-11-01

    I visualized the flash-boiling atomization of liquid jets released into a low pressure environment at frame rates of up to five million frames per second. Such a high temporal resolution allowed us to observe for the first time the bubble expansion mechanism that atomizes the jet. To visualize the dynamics in detail, I focused closely to the outflow of the nozzle using a long distance microscope objective. I documented an abrupt transition from a laminar to a fully external flashing jet by systematically reducing the ambient pressure. I performed experiments with different volatile liquids and using nozzles with different inner diameters. The inner diameters of the nozzles varied from 30 to 480 . Perfluorohexane (PFnH) was our main working fluid, but also methanol, ethanol and 1-bromopropane were tested. Surprisingly, minimum intensity profiles revealed spray angles close to ~360°, meaning drops are ejected in all directions. Also, I measured speeds of bubble expansion up to 140 m/s. That is 45 times faster than the upper bound for inertial growth speed in complete vacuum from the Rayleigh-Plesset equation. I also calculated the trajectories of the ejected droplets as well as the drop speed distribution using particle tracking. I expect that our results bring new insight into the flash-boiling atomization mechanism.

  2. Numerical analysis of high-speed Lithium jet flow under vacuum conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gordeev, Sergej, E-mail: sergej.gordeev@kit.edu; Groeschel, Friedrich; Stieglitz, Robert

    2016-11-01

    The EVEDA Li test loop (ELTL) [1] is aimed at validating the hydraulic stability of the Lithium (Li) target at a velocity up to 20 m/s at vacuum (≈10{sup −3} Pa). The ELTL has been designed to demonstrate the feasibility of the major components providing a neutron production liquid Li target for IFMIF. The rectangular shaped Li jet (cross-section 25 mm × 100 mm) necessitates for heat removal flow velocities of 15–20 m/s along a concave shaped back wall (curvature radius 250 mm) towards the outlet pipe, where the Li jet is subjected to vacuum before it finally enters the collecting quench tank. During the validation experiments within the ELTL acoustic waves within the target outlet pipe have been recorded, indicating potential cavitation processes in the jet impinging region, which may cause premature failures. In order to identify potential cavitation phenomena in correlation with the free jet flow in the outlet pipe a numerical study has been performed. The comparison measured and simulated acoustic emissions exhibits that experimentally deduced cavitation area coincides with the location of the jet wall impingement. The simulations further reveal that a part of the fluid after striking the wall even flows opposite to the gravity vector. This reversed flow is inherently unstable and characterized by waves at first growing and then bursting into droplets. The intense generation of small droplets increases significantly the Li free surface area and lead to a production of Li vapour, which is captured by the jet flow and reintroduced in the main flow. As the static pressure is recovered downstream due to jet impact, the vapour bubbles collapse and hence cavitation likely occurs.

  3. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    William S. McPhee

    1999-05-31

    construct a pre-prototype of the nozzle, blast head with wind curtain, sensors, and dust separator and test this system to assess the performance of the new design under controlled conditions at the contractor's facility. In phase III, the Contractor shall design and construct a prototype of the High Productivity Vacuum Blasting System, based on the results of the pre-prototype design and testing performed. This unit will be a full-scale prototype and will be tested at a designated Department of Energy (DOE) facility. Based on the results, the system performance, the productivity, and the economy of the improved vacuum blasting system will be evaluated.

  4. Ultra thin films of gadolinium deposited by evaporation in ultra high vacuum conditions: Composition, growth and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Sancho, O.A.; Castro-Gonzalez, D.; Araya-Pochet, J.A. [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Vargas-Castro, W.E., E-mail: william.vargascastro@ucr.ac.cr [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica)

    2011-02-01

    Ultra-thin gadolinium films with thicknesses between 8 and 101 A were deposited on AT-cut crystalline quartz substrates under ultra high vacuum conditions, and subsequently subjected to composition and morphologic characterization through X-ray photo-spectroscopy analysis and atomic force microscopy. Oxygen contamination is found on the samples, and its amount is estimated in terms of the thickness of an oxygen layer over the gadolinium films after subtracting the contribution to the XPS spectra of the underlying background. Atomic force microscope pictures provide evidence of having metal island films, with two growing regimes: the Volmer-Weber mode for the thinner films considered and the Stranski-Krastanov growing mode for the thicker ones. From evaluation of the sticking coefficient, the shape of the islands is approximated in terms of oblate spheroid caps and variation of the contact angle with film mass thickness is reported.

  5. Ultra high vacuum technology

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    A short introduction for some basic facts and equations. Subsquently, discussion about: Building blocks of an ultrahigh vacuum system - Various types of pumps required to reach uhv and methods to reduce these effects - Outgassing phenomena induced by the presence of a particle beam and the most common methods to reduce these effects It will be given some practical examples from existing CERN accelerators and discuss the novel features of the future LHC vacuum system.

  6. HIGH TEMPERATURE VACUUM MIXER

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2015-01-01

    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  7. A surface science compatible epifluorescence microscope for inspection of samples under ultra high vacuum and cryogenic conditions.

    Science.gov (United States)

    Marquardt, Christian; Paulheim, Alexander; Rohbohm, Nils; Merkel, Rudolf; Sokolowski, Moritz

    2017-08-01

    We modified an epi-illumination light microscope and mounted it on an ultra high vacuum chamber for investigating samples used in a surface science experiment. For easy access and bake out, all optical components are placed outside the vacuum and the sample is imaged through a glass window. The microscope can be operated in reflection brightfield or epifluorescence mode to image the sample surface or fluorescent dye molecules adsorbed on it. The homemade sample mounting was made compatible for the use under the microscope; sample temperatures as low as 6 K can be achieved. The performance of the microscope is demonstrated on two model samples: Brightfield-images of a well-prepared Ag(100) surface show a macroscopic corrugation of the surface, although low energy electron diffraction data indicate a highly ordered crystalline surface. The surface shows macroscopic protrusions with flat regions, about 20-200 μm in diameter, in between. Fluorescence images of diluted 3,4,9,10-perylene tetracarboxylicacid dianhydride (PTCDA) molecules adsorbed on an ultrathin epitaxial KCl film on the Ag(100) surface show a shading effect at surface protrusions due to an inclined angle of incidence of the PTCDA beam during deposition. For some preparations, the distribution of the fluorescence intensity is inhomogeneous and shows a dense network of bright patches about 5 μm in diameter related to the macroscopic corrugation of the surface. We propose that such a light microscope can aid many surface science experiments, especially those dealing with epitaxial growth or fluorescent materials.

  8. Preparation of DNA films for studies under vacuum conditions

    DEFF Research Database (Denmark)

    Smialek, M. A.; Balog, Richard; Jones, N. C.

    2010-01-01

    Experiments were carried out to determine the optimum conditions required for the preparation of uniform films of supercoiled plasmid DNA to be used in irradiation experiments under high vacuum conditions. Investigations reveal that significant damage to the DNA molecules occurs due to the evacua......Experiments were carried out to determine the optimum conditions required for the preparation of uniform films of supercoiled plasmid DNA to be used in irradiation experiments under high vacuum conditions. Investigations reveal that significant damage to the DNA molecules occurs due...... for the stability of the DNA molecules. The experimental results presented in this paper show that it may not be possible to perform experiments on so-called pure DNA under vacuum with no stabilizers being added to the sample before the evacuation process....

  9. Effect of High Temperature Storage in Vacuum, Air, and Humid Conditions on Degradation of Gold/Aluminum Wire Bonds in PEMs

    Science.gov (United States)

    Teverovsky, Alexander

    2006-01-01

    Microcircuits encapsulated in three plastic package styles were stored in different environments at temperatures varying from 130 C to 225 C for up to 4,000 hours in some cases. To assess the effect of oxygen, the parts were aged at high temperatures in air and in vacuum chambers. The effect of humidity was evaluated during long-term highly accelerated temperature and humidity stress testing (HAST) at temperatures of 130 C and 150 C. High temperature storage testing of decapsulated microcircuits in air, vacuum, and HAST chambers was carried out to evaluate the role of molding compounds in the environmentally-induced degradation and failure of wire bonds (WB). This paper reports on accelerating factors of environment and molding compound on WB failures. It has been shown that all environments, including oxygen, moisture, and the presence of molding compounds reduce time-to-failures compared to unencapsulated devices in vacuum conditions. The mechanism of the environmental effect on KB degradation is discussed.

  10. Novel vacuum conditions in inflationary collapse models

    Science.gov (United States)

    Bengochea, Gabriel R.; León, Gabriel

    2017-11-01

    Within the framework of inflationary models that incorporate a spontaneous reduction of the wave function for the emergence of the seeds of cosmic structure, we study the effects on the primordial scalar power spectrum by choosing a novel initial quantum state that characterizes the perturbations of the inflaton. Specifically, we investigate under which conditions one can recover an essentially scale free spectrum of primordial inhomogeneities when the standard Bunch-Davies vacuum is replaced by another one that minimizes the renormalized stress-energy tensor via a Hadamard procedure. We think that this new prescription for selecting the vacuum state is better suited for the self-induced collapse proposal than the traditional one in the semiclassical gravity picture. We show that the parametrization for the time of collapse, considered in previous works, is maintained. Also, we obtain an angular spectrum for the CMB temperature anisotropies consistent with the one that best fits the observational data. Therefore, we conclude that the collapse mechanism might be of a more fundamental character than previously suspected.

  11. Modification of Ultra-High Vacuum Surfaces Using Free Radicals

    CERN Document Server

    Vorlaufer, G

    2002-01-01

    In ultra-high vacuum systems outgassing from vacuum chamber walls and desorption of surface adsorbates are usually the factors which determine pressure and residual gas composition. In particular in beam vacuum systems of accelerators like the LHC, where surfaces are exposed to intense synchrotron radiation and bombardment by energetic ions and electrons, surface properties like the molecular desorption yield or secondary electron yield can strongly influence the performance of the accelerator. Well-established treatment methods like vacuum bake-out or glow-discharge cleaning have been successfully applied in the past to condition ultra-high vacuum surfaces, but these methods are sometimes difficult to carry out, for example if the vacuum chambers are not accessible. In this work, an alternative treatment method is investigated. This method is based on the strong chemical reactivity of free radicals, electrically neutral fragments of molecules. Free radicals (in the case of this work, nitrogen and oxygen radi...

  12. Physisorption of ammonia on AISI 304L stainless steel at different surface temperature under high vacuum conditions

    Directory of Open Access Journals (Sweden)

    A. de Castro

    2016-12-01

    Full Text Available The physisorption of ammonia molecules (sticking on the walls of a stainless steel pipe (AISI 304L has been studied at different wall temperatures (323-473K. The total amount of ammonia that is retained on the walls, once equilibrium is reached, has been measured by differentially-pumped mass spectrometry in gas exposure laboratory experiments. The results show ammonia retentions in the range of μg/cm2 resulting in a multilayer adsorption with lower amounts of stuck ammonia at higher temperatures of the stainless steel surface. The sticking coefficient follows an exponential decay evolution with time. The activation energy of the process has been estimated by an Arrhenius fit, assuming that the characteristic time for this decay is inversely proportional to the kinetic adsorption constant. A value of 0.15eV per ammonia molecule has been obtained, being in agreement with nominal values for the physisorption of small molecules or atoms (CO, N2, Ar… that can be found in the specialized literature. The implication of these results in the possible extrapolation to the ITER vacuum system under nitrogen seeded plasma operation is also addressed.

  13. Silicates materials of high vacuum technology

    CERN Document Server

    Espe, Werner

    2013-01-01

    Materials of High Vacuum Technology, Volume 2: Silicates covers silicate insulators of special importance to vacuum technology. The book discusses the manufacture, composition, and physical and chemical properties of technical glasses, quartz glass, quartzware, vycor glass, ceramic materials, mica, and asbestos.

  14. Anaerobic polymers as high vacuum leak sealants

    Science.gov (United States)

    Kendall, B. R. F.

    1982-01-01

    Anaerobic polymers are useful as solventless leak sealants with good vacuum properties at moderate temperatures. Loctite 290 can seal leaks in a range generally encountered in carefully constructed ultrahigh vacuum and high vacuum systems. It was found that small leaks are sealed best under vacuum, whereas large leaks should be sealed at atmospheric pressure. The high-temperature behavior of Loctite 290 is limited by its fast cure, which prevents deep penetration into small leaks; cracking eventually occurs at the entrance to the leak. Repeated thermal cycling to about 300 C is possible, however, provided viscosity, curing time, and leak size are properly matched to ensure penetration into the body of the leak. This may require special formulations for high temperature vacuum applications.

  15. Standard Model Vacuum Stability and Weyl Consistency Conditions

    DEFF Research Database (Denmark)

    Antipin, Oleg; Gillioz, Marc; Krog, Jens

    2013-01-01

    At high energy the standard model possesses conformal symmetry at the classical level. This is reflected at the quantum level by relations between the different beta functions of the model. These relations are known as the Weyl consistency conditions. We show that it is possible to satisfy them...... order by order in perturbation theory, provided that a suitable coupling constant counting scheme is used. As a direct phenomenological application, we study the stability of the standard model vacuum at high energies and compare with previous computations violating the Weyl consistency conditions....

  16. Ultra-high vacuum technology for accelerators

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Hilleret, Noël; Strubin, Pierre M

    2002-01-01

    The lectures will start with a review of the basics of vacuum physics required to build Ultra High Vacuum (UHV) systems, such as static and dynamic outgassing. Before reviewing the various pumping and measurement devices, including the most modern one like Non Evaporable Getter (NEG) coatings, an overview of adequate materials to be used in UHV systems will be given together with their treatment (e.g. cleaning procedures and bake out). Practical examples based on existing or future accelerators will be used to illustrate the topics. Finally, a short overview of modern vacuum controls and interlocks will be given.

  17. Modelling of nectarine drying under near infrared - Vacuum conditions.

    Science.gov (United States)

    Alaei, Behnam; Chayjan, Reza Amiri

    2015-01-01

    Drying of nectarine slices was performed to determine the thermal and physical properties in order to reduce product deterioration due to chemical reactions, facilitate storage and lower transportation costs. Because nectarine slices are sensitive to heat with long drying period, the selection of a suitable drying approach is a challenging task. Infrared-vacuum drying can be used as an appropriate method for susceptible materials with high moisture content such as nectarine slices. Modelling of nectarine slices drying was carried out in a thin layer near infraredvacuum conditions. Drying of the samples was implemented at the absolute pressures of 20, 40 and 60 kPa and drying temperatures of 50, 60 and 70°C. Drying behaviour of nectarine slices, as well as the effect of drying conditions on moisture loss trend, drying rate, effective diffusion coefficient, activation energy, shrinkage, colour and energy consumption of nectarine slices, dried in near infrared-vacuum dryer are discussed in this study. Six mathematical models were used to predict the moisture ratio of the samples in thin layer drying. The Midilli model had supremacy in prediction of nectarine slices drying behaviour. The maximum drying rates of the samples were between 0.014-0.047 gwater/gdry material·min. Effective moisture diffusivity of the samples was estimated in the ranges of 2.46·10-10 to 6.48·10-10 m2/s. Activation energy were computed between 31.28 and 35.23 kJ/mol. Minimum shrinkage (48.4%) and total colour difference (15.1) were achieved at temperature of 50°C and absolute pressure of 20 kPa. Energy consumption of the tests was estimated in the ranges of 0.129 to 0.247 kWh. Effective moisture diffusivity was increased with decrease of vacuum pressure and increase of drying temperature but effect of drying temperature on effective moisture diffusivity of nectarine slices was more than vacuum pressure. Activation energy was decreased with decrease in absolute pressure. Total colour

  18. Second-Order Nonlinear Optical Microscopy of a H–Si(1111 × 1 Surface in Ultra-High Vacuum Conditions

    Directory of Open Access Journals (Sweden)

    Yoshihiro Miyauchi

    2012-01-01

    Full Text Available This paper reviews the use of optical sum frequency generation (SFG and second harmonic generation (SHG microscopy under ultra-high vacuum (UHV conditions to observe the dynamics of a hydrogen terminated Si(1111 × 1 surface. First, we took SFG and SHG microscopic images of the surface after IR light pulse irradiation and found that the SHG and nonresonant SFG signals were enhanced, probably due to the formation of dangling bonds after hydrogen desorption. Second, we observed time-resolved SFG intensity images of a H–Si(1111 × 1 surface. After visible pump light irradiation, the nonresonant SFG signal increased at probe delay time 0 ps and then decreased over a life time of 565 ps. The resonant SFG signal reduced dramatically at 0 ps and then recovered with an anisotropic line shape over a life time of 305 ps. The areas of modulated SFG signals at delay time 277 ps were expanded with an anisotropic aspect. Finally, we observed SFG intensity images of hydrogen deficiency on a Si(1111 × 1 surface as a function of temperature. These images of the H–Si(111 surface, taken with a spatial resolution of 5 μm at several temperatures from 572 to 744 K, showed that the hydrogen desorbs homogeneously.

  19. Materials for high vacuum technology, an overview

    CERN Document Server

    Sgobba, Stefano

    2007-01-01

    In modern accelerators stringent requirements are placed on materials of vacuum systems. Their physical and mechanical properties, machinability, weldability or brazeability are key parameters. Adequate strength, ductility, magnetic properties at room as well as low temperatures are important factors for vacuum systems of accelerators working at cryogenic temperatures, such as the Large Hadron Collider (LHC) under construction at CERN. In addition, baking or activation of Non-Evaporable Getters (NEG) at high temperatures impose specific choices of material grades of suitable tensile and creep properties in a large temperature range. Today, stainless steels are the dominant materials of vacuum constructions. Their metallurgy is extensively treated. The reasons for specific requirements in terms of metallurgical processes are detailed, in view of obtaining adequate purity, inclusion cleanliness, and fineness of the microstructure. In many cases these requirements are crucial to guarantee the final leak tightnes...

  20. A squeezed light source operated under high vacuum.

    Science.gov (United States)

    Wade, Andrew R; Mansell, Georgia L; Chua, Sheon S Y; Ward, Robert L; Slagmolen, Bram J J; Shaddock, Daniel A; McClelland, David E

    2015-12-14

    Non-classical squeezed states of light are becoming increasingly important to a range of metrology and other quantum optics applications in cryptography, quantum computation and biophysics. Applications such as improving the sensitivity of advanced gravitational wave detectors and the development of space-based metrology and quantum networks will require robust deployable vacuum-compatible sources. To date non-linear photonics devices operated under high vacuum have been simple single pass systems, testing harmonic generation and the production of classically correlated photon pairs for space-based applications. Here we demonstrate the production under high-vacuum conditions of non-classical squeezed light with an observed 8.6 dB of quantum noise reduction down to 10 Hz. Demonstration of a resonant non-linear optical device, for the generation of squeezed light under vacuum, paves the way to fully exploit the advantages of in-vacuum operations, adapting this technology for deployment into new extreme environments.

  1. On High Vacuum Densification of Soft Foundation Treatment

    Directory of Open Access Journals (Sweden)

    Guo Mei Ling

    2016-01-01

    Full Text Available The high vacuum densification, which inserted the vacuum tube to increase the drainage channel, set up the improved drainage system so that it can effectively reduce the underground water level, can be used for the reinforcement of the deep soft foundation. According to analyze the preparation and process of high vacuum densification, and summarize the control points of high vacuum densification, it renders great value to the constuction of soft foundation treatment.

  2. High Vacuum Techniques for Anionic Polymerization

    KAUST Repository

    Ratkanthwar, Kedar

    2015-09-01

    Anionic polymerization high vacuum techniques (HVTs) are the most suitable for the preparation of polymer samples with well-defined complex macromolecular architectures. Though HVTs require glassblowing skill for designing and making polymerization reactor, it is the best way to avoid any termination of living polymers during the number of steps for the synthesis of polymers with complex structure. In this chapter, we describe the different polymerization reactors and HVTs for the purification of monomers, solvents, and other reagents for anionic polymerization as well as few model reactions for the synthesis of polymers with simple to complex structure.

  3. Understanding and Improving High Voltage Vacuum Insulators for Microsecond Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Javedani, J B; Goerz, D A; Houck, T L; Lauer, E J; Speer, R D; Tully, L K; Vogtlin, G E; White, A D

    2007-03-05

    High voltage insulation is one of the main areas of pulsed power research and development, and dielectric breakdown is usually the limiting factor in attaining the highest possible performance in pulsed power devices. For many applications the delivery of pulsed power into a vacuum region is the most critical aspect of operation. The surface of an insulator exposed to vacuum can fail electrically at an applied field more than an order or magnitude below the bulk dielectric strength of the insulator. This mode of breakdown, called surface flashover, imposes serious limitations on the power flow into a vacuum region. This is especially troublesome for applications where high voltage conditioning of the insulator and electrodes is not practical and for applications where relatively long pulses, on the order of several microseconds, are required. The goal of this project is to establish a sound fundamental understanding of the mechanisms that lead to surface flashover, and then evaluate the most promising techniques to improve vacuum insulators and enable high voltage operation at stress levels near the intrinsic bulk breakdown limits of the material. The approach we proposed and followed was to develop this understanding through a combination of theoretical and computation methods coupled with experiments to validate and quantify expected behaviors. In this report we summarize our modeling and simulation efforts, theoretical studies, and experimental investigations. The computational work began by exploring the limits of commercially available codes and demonstrating methods to examine field enhancements and defect mechanisms at microscopic levels. Plasma simulations with particle codes used in conjunction with circuit models of the experimental apparatus enabled comparisons with experimental measurements. The large scale plasma (LSP) particle-in-cell (PIC) code was run on multiprocessor platforms and used to simulate expanding plasma conditions in vacuum gap regions

  4. Conditioning of the vacuum vessel walls of tokamaks, a preliminary look

    Energy Technology Data Exchange (ETDEWEB)

    Sink, D.A.

    1976-03-01

    The main features and operating characteristics of the primary vacuum system of many of the presently operating tokamak devices are presented. Particular attention is paid to the methods used to condition and clean the vessel walls in situ. For the devices discussed, a combination of a high-temperature bakeout and/or discharge cleaning is employed. In addition, discussions of the vacuum systems and wall conditioning methods anticipated for the next generation of tokamaks are presented. Since this report was written during a limited time period, it should be considered as preliminary and is not intended to be a general review. Much of the information that is presented was obtained by private communication and there is no bibliography. This study was initiated to aid in the design of TFTR. As presently envisioned, the TFTR vacuum system and methods for wall conditioning are consistent with what is presently practiced.

  5. A Target Projector for Videogrammetry Under Vacuum Conditions

    Science.gov (United States)

    Roose, Stephane; Mazzoli, Alexandra; Barzin, Pascal; Jamotton, Pierre; Sablerolle, Steven; Tavares, Andre; Doyle, Dominic

    2012-07-01

    distortion of the materialized point can be tracked with respect to the test article itself. • Projected dots are not materialized on the object. Practically a specific point cannot be tracked by this method. The dense cloud of projected dots allows sampling the surface or the shape in an arbitrary way. The Target Projector System (TPS), described here (Fig.1), was designed and manufactured to operate in the Large Space Simulator (LSS) of ESAof ESA under thermal vacuum conditions and to have a minimized temperature exchange with its environment. It is operational over a temperature range of 90K to 350 K, and has a wavelength of 808 nm. Qualification tests and results under vacuum, along with an assessment of the videogrammetric accuracy achievable for various configurations of this unique device are presented.

  6. Conceptual design and application studies of piezoelectric crystal motors under ultra-high vacuum conditions; Konzepterstellung und Verwendungsmoeglichkeiten eines Piezokristallmotors im Ultrahochvakuum

    Energy Technology Data Exchange (ETDEWEB)

    Nagler, Jens

    2009-08-15

    For the operation of accelerators it is important that motions in the vacuum occur. The here produced diploma thesis deals with the possibility to perform thes motions with piezocrystal motors in order to abandon wear-susceptible membrane bellows. For this studies have been performed, which should show for which it is useful to apply a piezocrystal motor. Limits are shown, advances and disadvantages are weighted in the thesis. Construction with with subsequent test of a tandem facility and an outlook on possible future concepts form the main content. [German] Fuer den Betrieb von Beschleunigern ist es wichtig, dass Bewegungen im Vakuum stattfinden. Die hier angefertigte Diplomarbeit befasst sich mit der Moeglichkeit, diese Bewegungen mit Piezokristallmotoren durchzufuehren, um auf verschleissanfaellige Membranbaelge zu verzichten. Hierfuer sind Studien durchgefuehrt worden, die zeigen sollen, wofuer es ratsam ist, einen Piezokristallmotor zu verwenden. Grenzen werden aufgezeigt, Vor- und Nachteile werden in der Arbeit abgewogen. Konstruktion mit anschliessenden Tests eines Tandemaufbaus und ein Ausblick auf moegliche zukuenftige Konzepte bilden den Kerninhalt. (orig.)

  7. New Materials for Vacuum Chambers in High Energy Physics

    CERN Document Server

    Garion, Cédric

    2014-01-01

    Vacuum chambers must fulfil ultra-high vacuum requirements while withstanding thermo-mechanical loads. This is particularly true in high energy particle accelerator where interactions of particles with matter may induce thermal load, material activation, background… The choice of the material of the vacuum chamber is crucial for the final application. Metals such as stainless steel, copper and aluminium are usually used. Even with outstanding mechanical and physical properties, beryllium is used for very specific applications because of its cost and toxicity.Ceramics such as alumina are usually used for fast magnet vacuum chambers. With the next generation of high energy physics accelerator generation such as CLIC and TLEP, the problematic of high cyclic thermal load induced by synchrotron radiation is raised. This paper aims at defining some figures of merit of different materials with respect to several load scenarios and presents briefly their vacuum compatibility.

  8. Gauges for fine and high vacuum

    CERN Document Server

    Jousten, K

    2007-01-01

    Vacuum gauges for use in accelerators have to cover about 17 decades of pressure, from 10–12 Pa to 105 Pa. In this article we describe the history, measurement mode, design, accuracy and calibration of the gauges used down to 10–5 Pa. We focus on commercially available types of gauges, i.e., mechanical gauges, piezoresistive and capacitance diaphragm gauges, thermal conductivity gauges, and spinning rotor gauges.

  9. Highly sensitive vacuum ion pump current measurement system

    Science.gov (United States)

    Hansknecht, John Christopher [Williamsburg, VA

    2006-02-21

    A vacuum system comprising: 1) an ion pump; 2) power supply; 3) a high voltage DC--DC converter drawing power from the power supply and powering the vacuum pump; 4) a feedback network comprising an ammeter circuit including an operational amplifier and a series of relay controlled scaling resistors of different resistance for detecting circuit feedback; 5) an optional power block section intermediate the power supply and the high voltage DC--DC converter; and 6) a microprocessor receiving feedback information from the feedback network, controlling which of the scaling resistors should be in the circuit and manipulating data from the feedback network to provide accurate vacuum measurement to an operator.

  10. Icy Regolith Excavation and Volatile Capture under Vacuum Conditions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA Kennedy Space Center is developing a testbed for producing large volume mixtures of ice and regolith under low pressure inside a laboratory vacuum...

  11. A multipurpose ultra-high vacuum-compatible chamber for in situ X-ray surface scattering studies over a wide range of temperature and pressure environment conditions

    Science.gov (United States)

    Ferrer, P.; Rubio-Zuazo, J.; Heyman, C.; Esteban-Betegón, F.; Castro, G. R.

    2013-03-01

    A low/high temperature (60-1000K) and pressure (10-10-3x103 mbar) "baby chamber", specially adapted to the grazing-incidence X-ray scattering station, has been designed, developed and installed at the Spanish CRG BM25 SpLine beamline at European Synchrotron Radiation Facility. The chamber has a cylindrical form with 100 mm of diameter, built on a 360° beryllium nipple of 150 mm height. The UHV equipment and a turbo pump are located on the upper part of the chamber to leave a wide solid angle for exploring reciprocal space. The chamber features 4 CF16 and 5 CF40 ports for electrical feed through and leak valves, ion gun, etc. The heat exchanger is a customized compact LN2 (or LHe) continuous flow cryostat. The sample is mounted on a Mo support on the heat exchanger, which has in the back side a BORALECTRIC® Heater Elements. Experiments of surfaces/interfaces/ multilayer materials, thin films or single crystals in a huge variety of environments can be performed, also in situ studies of growth or evolution of the samples. Data measurement can be collected with a punctual and a bi-dimensional detector, being possible to simultaneously use them.

  12. Ultra-high vacuum in superconducting accelerator rings

    Science.gov (United States)

    Bazanov, A. M.; Butenko, A. V.; Galimov, A. R.; Lugovnin, A. K.; Smirnov, A. V.

    2016-12-01

    Achieving the ultra-high vacuum (UHV) in the collider and booster of the NICA project is one of the main challenges when creating this device. It determines the need for a serious approach to this issue and conducting research in this direction. First, it is necessary to understand the effect of the various components of the vacuum systems on the degree of vacuum. It is also necessary to carry out studies of pumping devices for producing the required vacuum (10-9 Pa) in the beam chamber and choose the most optimal pumping scheme. At the same time, it is necessary to figure out how various operations are carried out with the vacuum chamber: preparation of vacuum surfaces, letting in the atmosphere, and warming the chamber after closing the influence on the degree of vacuum and the composition of the residual gas. The temperature may vary from room temperature to liquid helium temperature due to the difficulty of keeping the beam-chamber walls at a constant temperature, including the inner components. This complicates the processes taking place within it. Additional complexity arises due the heating of the chamber walls by various processes during the operation of the accelerator (for example, cycling the magnetic field).

  13. New perspectives in vacuum high voltage insulation. II. Gas desorption

    CERN Document Server

    Diamond, W T

    1998-01-01

    An examination has been made of gas desorption from unbaked electrodes of copper, niobium, aluminum, and titanium subjected to high voltage in vacuum. It has been shown that the gas is composed of water vapor, carbon monoxide, and carbon dioxide, the usual components of vacuum outgassing, plus an increased yield of hydrogen and light hydrocarbons. The gas desorption was driven by anode conditioning as the voltage was increased between the electrodes. The gas is often desorbed as microdischarges-pulses of a few to hundreds of microseconds-and less frequently in a more continuous manner without the obvious pulsed structure characteristic of microdischarge activity. The quantity of gas released was equivalent to many monolayers and consisted mostly of neutral molecules with an ionic component of a few percent. A very significant observation was that the gas desorption was more dependent on the total voltage between the electrodes than on the electric field. It was not triggered by field-emitted electrons but oft...

  14. Large high-vacuum systems for CERN accelerators

    Science.gov (United States)

    Strubin, P.

    2008-05-01

    CERN operated over the more than 50 years of its existence particle accelerators and storage rings ranging from a few tens of metre to 27 km, the size of its latest project, the Large Hadron Collider (LHC) which is under construction and will be started in 2008. The challenges began with the Intersection Storage Rings (ISR) in the seventies. With a beam pipe length of 2 × 1 km, this accelerator required innovative solutions like bake-out and glow discharge to achieve the required static vacuum level, fight against beam-induced pressure increases and cancel beam neutralisation by trapped electrons. The vacuum system of the Large Electron Positron (LEP) storage ring (in operation between 1989 and 2001) of a total length of 27 km had to cope with very high levels of synchrotron power. The beam vacuum system of LHC (2 × 27 km) integrates some parts at 1.9 K and others at room temperature and will also have to cope with dynamic effects. In addition to the beam vacuum system, LHC requires insulation vacuum for the superconducting magnets and the helium distribution line. Whereas the required pressure is not very low, the leak detection and localisation is significantly more demanding for the insulation vacuum than for the beam vacuum because of the large volumes and the thermal insulation. When the size of an accelerator grows, the difficulties are not only to get a clean and leak tight vacuum system, but also to be able to measure reliably pressure or gas composition over long distances. Furthermore, in the case of LHC the integration of the beam vacuum system was particularly difficult because of the complexity induced by a superconducting magnet scheme and the reduced space available for the beam pipes. Planning and logistics aspects during installation, including the usage of mobile pumping and diagnostic means, were much more difficult to manage in LHC than in previous projects.

  15. Overview of High Power Vacuum Dry RF Load Designs

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  16. Design considerations for achieving high vacuum integrity in fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, G.M.; Haines, J.R.

    1983-01-01

    Achieving high vacuum integrity in fusion devices requires close attention to both the overall system configuration and the design details of joints and seals. This paper describes the factors in selecting the system configuration, from a vacuum standpoint, for the Princeton Plasma Physics Laboratory (PPPL) DCT-8 Tokamak device. The DCT-8 (driven current tokamak) is the eighth design in a series of tokamak concepts defined to cover the magnetic confinement and development gap between the Tokamak Fusion Test Reactor (TFTR) and the Engineering Test Reactor (ETR). Leak detection concept development is considered a vital activity, as well as the definition of a configuration that minimizes the consequences of leaks. A major part of the vacuum boundaries of the magnet system and the plasma system is common. For the major penetrations, primary and secondary seals are provided with vacuum control over the region between seals. The intent is to instrument these cavities and provide automated recordings of these measurements for leak maintenance.

  17. Vehicle-Level Oxygen/Methane Propulsion System Hotfire Testing at Thermal Vacuum Conditions

    Science.gov (United States)

    Morehead, Robert L.; Melcher, J. C.; Atwell, Matthew J.; Hurlbert, Eric A.; Desai, Pooja; Werlink, Rudy

    2017-01-01

    A prototype integrated liquid oxygen/liquid methane propulsion system was hot-fire tested at a variety of simulated altitude and thermal conditions in the NASA Glenn Research Center Plum Brook Station In-Space Propulsion Thermal Vacuum Chamber (formerly B2). This test campaign served two purposes: 1) Characterize the performance of the Plum Brook facility in vacuum accumulator mode and 2) Collect the unique data set of an integrated LOX/Methane propulsion system operating in high altitude and thermal vacuum environments (a first). Data from this propulsion system prototype could inform the design of future spacecraft in-space propulsion systems, including landers. The test vehicle for this campaign was the Integrated Cryogenic Propulsion Test Article (ICPTA), which was constructed for this project using assets from the former Morpheus Project rebuilt and outfitted with additional new hardware. The ICPTA utilizes one 2,800 lbf main engine, two 28 lbf and two 7 lbf reaction control engines mounted in two pods, four 48-inch propellant tanks (two each for liquid oxygen and liquid methane), and a cold helium system for propellant tank pressurization. Several hundred sensors on the ICPTA and many more in the test cell collected data to characterize the operation of the vehicle and facility. Multiple notable experiments were performed during this test campaign, many for the first time, including pressure-fed cryogenic reaction control system characterization over a wide range of conditions, coil-on-plug ignition system demonstration at the vehicle level, integrated main engine/RCS operation, and a non-intrusive propellant mass gauging system. The test data includes water-hammer and thermal heat leak data critical to validating models for use in future vehicle design activities. This successful test campaign demonstrated the performance of the updated Plum Brook In-Space Propulsion thermal vacuum chamber and incrementally advanced the state of LOX/Methane propulsion

  18. Lubricity and Tribochemical Reactivity of Advanced Materials Under High Vacuum

    Science.gov (United States)

    Igartua, A.; Berriozabal, E.; Zabala, B.; Pagano, F.; Minami, I.; Doerr, N.; Gabler, C.; Nevshupa, R.; Roman, E.; Pleth Nielsen, L.; Louring, S.; Muntada, L.

    2015-09-01

    The aim of this study was to develop and characterize advanced tribological materials for space applications. For this purpose a newly developed Ultra High Vacuum (UHV) tribometer CA3UHV was used to determine friction, wear and triboemission of gases and volatiles from atmospheric pressure down to high or ultrahigh vacuum. The study was focused on two classes of materials: a) advanced lubricants based on ionic liquids (ILs), b) engineered diamond-like carbon films as anti- wear and low-friction coatings. Tribochemical mechanisms were identified by analyzing gas triboemission involved in the generation of protective tribofilm layer and/or transfer film and surface chemical characterization.

  19. Direct-write polymer nanolithography in ultra-high vacuum

    Directory of Open Access Journals (Sweden)

    Woo-Kyung Lee

    2012-01-01

    Full Text Available Polymer nanostructures were directly written onto substrates in ultra-high vacuum. The polymer ink was coated onto atomic force microscope (AFM probes that could be heated to control the ink viscosity. Then, the ink-coated probes were placed into an ultra-high vacuum (UHV AFM and used to write polymer nanostructures on surfaces, including surfaces cleaned in UHV. Controlling the writing speed of the tip enabled the control over the number of monolayers of the polymer ink deposited on the surface from a single to tens of monolayers, with higher writing speeds generating thinner polymer nanostructures. Deposition onto silicon oxide-terminated substrates led to polymer chains standing upright on the surface, whereas deposition onto vacuum reconstructed silicon yielded polymer chains aligned along the surface.

  20. Sealing Materials for Use in Vacuum at High Temperatures

    Science.gov (United States)

    Pettit, Donald R.; Camarda, Charles J.; Lee Vaughn, Wallace

    2012-01-01

    Sealing materials that can be applied and left in place in vacuum over a wide range of temperatures (especially temperatures of a few thousand degrees Celsius) have been conceived and investigated for potential utility in repairing thermal-protection tiles on the space shuttles in orbit before returning to Earth. These materials are also adaptable to numerous terrestrial applications that involve vacuum processing and/or repair of structures that must withstand high temperatures. These materials can be formulated to have mechanical handling characteristics ranging from almost freely flowing liquid-like consistency through paste-like consistency to stiff puttylike consistency, and to retain these characteristics in vacuum until heated to high curing temperatures. A sealing material of this type can be formulated to be used in any of several different ways for example, to be impregnated into a high-temperature-fabric patch, impregnated into a high-temperature-fabric gasket for sealing a patch, applied under a patch, or applied alone in the manner of putty or wallboard compound. The sealing material must be formulated to be compatible with, and adhere to, the structural material(s) to be repaired. In general, the material consists of a vacuum-compatible liquid containing one or more dissolved compound(s) and/or mixed with suspended solid particles. Depending on the intended application, the liquid can be chosen to be of a compound that can remain in place in vacuum for a time long enough to be useful, and/or to evaporate or decompose in a controlled way to leave a useful solid residue behind. The evaporation rate is determined by proper choice of vapor pressure, application of heat, and/or application of ultraviolet light or other optical radiation. The liquid chosen for the original space shuttle application is a commercial silicone vacuum-pump oil.

  1. Vacuum stripping of ethanol during high solids fermentation of corn.

    Science.gov (United States)

    Shihadeh, Jameel K; Huang, Haibo; Rausch, Kent D; Tumbleson, Mike E; Singh, Vijay

    2014-05-01

    In corn-ethanol industry, yeast stress inducing glucose concentrations produced during liquefaction and subsequent high ethanol concentrations produced during fermentation restrict slurry solids to 32 % w/w. These limits were circumvented by combining two novel technologies: (1) granular starch hydrolyzing enzyme (GSHE) to break down starch simultaneously with fermentation and (2) vacuum stripping to remove ethanol. A vacuum stripping system was constructed and applied to fermentations at 30, 40, and 45 % solids. As solids increased from 30 to 40 %, ethanol yield decreased from 0.35 to 0.29 L/kg. Ethanol yield from 45 % solids was only 0.18 L/kg. An improvement was conducted by increasing enzyme dose from 0.25 to 0.75 g/g corn and reducing yeast inoculum by half. After improvement, ethanol yield from 40 % solids vacuum treatment increased to 0.36 L/kg, comparable to ethanol yield from 30 % solids (control).

  2. Shelf life of fresh foal meat under MAP, overwrap and vacuum packaging conditions.

    Science.gov (United States)

    Lorenzo, José M; Gómez, María

    2012-12-01

    The objective of this study was to investigate the physico-chemical properties, the microbial counts and the sensory properties' changes of foal steaks packed under various conditions. The experimental packaging systems were: (i) vacuum packaging (VP), (ii) overwrap packaging and (iii) two modified atmosphere packaging methods (MAP): high O₂ MAP (80% O₂+20% CO₂) and low O₂ MAP (30% O₂+70% CO₂). The meat was stored at 2 °C during 14 days and tested for pH, colour, lipid and protein oxidation, microbial counts and sensory assessment of odour, colour and appearance. Of the two MAP, overwrap and VP, both MAP were the most effective treatments for the inhibition of the total viable counts (TVC), Pseudomonas spp., psychrotrophic aerobic bacteria, lactic acid bacteria, Enterobacteriaceae as well as moulds and yeast. According to the sensory evaluation, foal steaks packed under overwrap and MAP treatments resulted unacceptable after 7 days of storage, whereas the vacuum-packed meat was still acceptable. Moreover, the redness value decreased significantly (Pfoal steaks from overwrap packaging and MAP conditions had a greater increase of TBAR'S values and carbonyl content during the storage time. High O₂ levels affected foal meat quality negatively, while anaerobic conditions extended the meat's shelf life up to 14 days. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Spectroscopic study of cystine adsorption on pyrite surface: From vacuum to solution conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Arenillas, M.; Mateo-Marti, E., E-mail: mateome@cab.inta-csic.es

    2015-09-08

    Highlights: • Successful adsorption of cystine on pyrite surface under several conditions. • Detailed XPS spectroscopic characterization of cystine adsorption on pyrite surface. • Spectroscopy evidence, oxidation and anoxic conditions adjust molecular adsorption. • Molecular chemistry on pyrite is driven depending on the surrounding conditions. • The cystine/pyrite(100) model is in good agreement with Wächtershäuser’s theory. - Abstract: We characterized the adsorption of cystine molecules on pyrite surface via X-ray photoelectron spectroscopy. Anoxic conditions were simulated under ultra-high-vacuum conditions. In contrast, to simulate oxidation conditions, the molecules were adsorbed on pyrite surface from solution. A novel comparative analysis revealed remarkable differences with respect to molecular adsorption and surface chemistry induced by environmental conditions. Molecular adsorption under anoxic conditions was observed to be more favorable, concentrating a large number of molecules on the surface and two different chemical species. In contrast, the presence of oxygen induced an autocatalytic oxidation process on the pyrite surface, which facilitated water binding on pyrite surface and partially blocked molecular adsorption. Pyrite is a highly reactive surface and contains two crucial types of surface functional groups that drive molecular chemistry on the surface depending on the surrounding conditions. Therefore, the system explored in this study holds interesting implications for supporting catalyzed prebiotic chemistry reactions.

  4. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    Science.gov (United States)

    Prasad, D. N.; Ayyappan, R.; Kamble, L. P.; Singh, J. P.; Muralikrishna, L. V.; Alex, M.; Balagi, V.; Mukhopadhyay, P. K.

    2008-05-01

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ~1 × 10-5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mm×160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face & diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6×10-9 m bar ltr/sec in vacuum mode and 2×10-7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5×10-5 mbar, the new valve achieved vacuum 7.4×10-6mbar in the same time under the same conditions.

  5. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum.

    Science.gov (United States)

    West, Adam D; Lasner, Zack; DeMille, David; West, Elizabeth P; Panda, Cristian D; Doyle, John M; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2017-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung x rays; indeed, this is the basic principle behind the operation of standard x-ray sources. However, in laboratory setups where x-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce x rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. The authors present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. They describe the characterization of the observed x-ray radiation, its relation to the observed leakage current in the device, the steps taken to contain and mitigate the radiation hazard, and suggested safety guidelines.

  6. An Underappreciated Radiation Hazard from High Voltage Electrodes in Vacuum

    CERN Document Server

    West, Adam; DeMille, David; West, Elizabeth; Panda, Cristian; Doyle, John; Gabrielse, Gerald; Kryskow, Adam; Mitchell, Corinne

    2016-01-01

    The use of high voltage (HV) electrodes in vacuum is commonplace in physics laboratories. In such systems, it has long been known that electron emission from an HV cathode can lead to bremsstrahlung X-rays; indeed, this is the basic principle behind the operation of standard X-ray sources. However, in laboratory setups where X-ray production is not the goal and no electron source is deliberately introduced, field-emitted electrons accelerated by HV can produce X-rays as an unintended hazardous byproduct. Both the level of hazard and the safe operating regimes for HV vacuum electrode systems are not widely appreciated, at least in university laboratories. A reinforced awareness of the radiation hazards associated with vacuum HV setups would be beneficial. We present a case study of a HV vacuum electrode device operated in a university atomic physics laboratory. We describe the characterisation of the observed X-ray radiation, its relation to the observed leakage current in the device, the steps taken to contai...

  7. Processing of extraterrestrial materials by high temperature vacuum vaporization

    Science.gov (United States)

    Grimley, R. T.; Lipschutz, M. E.

    1983-01-01

    It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

  8. Effects of vacuum packaging conditions on the quality, biochemical changes and the durability of ostrich meat.

    Science.gov (United States)

    Brenesselová, Martina; Koréneková, Beáta; Mačanga, Ján; Marcinčák, Slavomír; Jevinová, Pavlína; Pipová, Monika; Turek, Peter

    2015-03-01

    In this study, the effects of vacuum packaging conditions on the concentrations of lactic acid, malondialdehyde, pH, microbial and sensory analysis were determined during chilled storage of ostrich meat. Meat was packed as follows: vacuum packed from 1st day (VP-1), vacuum packed from 3rd day (VP-3) and non-vacuum packed (NVP). Analysis were performed at 1st, 7th, 14th, 21st day after slaughter. Meat consisted of 74.69% water, 2.29% fats, 20.95% proteins. Package conditions had significant effect on the pH (NVP: 6.54 on the 14th day, VP-1: 6.05 and VP-3: 6.07 on the 21th day pvacuum packed from 1st day is necessary for the 21 days storage of ostrich meat. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Chemical changes exhibited by latent fingerprints after exposure to vacuum conditions.

    Science.gov (United States)

    Bright, Nicholas J; Willson, Terry R; Driscoll, Daniel J; Reddy, Subrayal M; Webb, Roger P; Bleay, Stephen; Ward, Neil I; Kirkby, Karen J; Bailey, Melanie J

    2013-07-10

    The effect of vacuum exposure on latent fingerprint chemistry has been evaluated. Fingerprints were analysed using a quartz crystal microbalance to measure changes in mass, gas chromatography mass spectrometry to measure changes in lipid composition and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine changes in the content of water, fatty acids and their esters after exposure to vacuum. The results are compared with samples aged under ambient conditions. It was found that fingerprints lose around 26% of their mass when exposed to vacuum conditions, equivalent to around 5 weeks ageing under ambient conditions. Further exposure to vacuum causes a significant reduction in the lipid composition of a fingerprint, in particular with the loss of tetradecanoic and pentadecanoic acid, that was not observed in ambient aged samples. There are therefore implications for sequence in which fingerprint development procedures (for example vacuum metal deposition) are carried out, as well as the use of vacuum based methods such as secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption ionisation (MALDI) in the study of fingerprint chemistry. Copyright © 2013. Published by Elsevier Ireland Ltd.

  10. Vacuum Window Design for High-Power Lasers

    CERN Document Server

    Shaftan, T V

    2005-01-01

    One of the problems in the high-power lasers design is in outcoupling of a powerful laser beam out of a vacuum volume into atmosphere. Usually the laser device is located inside a vacuum tank. The laser radiation is transported to the outside world through the transparent vacuum window. While considered transparent, some of the light passing through the glass is absorbed and converted to heat. For most applications, these properties are academic curiosities; however, in multi-kilowatt lasers, the heat becomes significant and can lead to a failure. The absorbed power can result in thermal stress, reduction of light transmission and, consequently, window damage. Modern optical technology has developed different types of glass (Silica, BK7, diamond, etc.) that have high thermal conductivity and damage threshold. However, for kilo- and megawatt lasers the issue still remains open. In this paper we present a solution that may relieve the heat load on the output window. We discuss advantages and issues of this part...

  11. Drying characteristics of zucchini slices under periodic infrared-microwave vacuum conditions

    Science.gov (United States)

    Chayjan, Reza Amiri; Dibagar, Nesa; Alaei, Behnam

    2017-12-01

    The purpose of the presented study was to describe the effects of various drying conditions on the drying behavior of zucchini slices as well as specifications of diffusivity, activation energy, shrinkage, and color. Zucchini samples, as the richest fount of macronutrient and micronutrient, were subjected to periodic microwave vacuum drying (at 450 W) at three levels of temperature (40, 50 and 60 °C), absolute pressure (20, 40 and 60 kPa) and exposure time (20-3, 30-4.5 and 40-6 s-min). An increase in the drying temperature and exposure time along with a decrease in absolute pressure caused a reduction in total drying time, however, greater heat damages and adversely texture and color effects were observed in this case. The effective moisture diffusivity of zucchini varied between 5.41×10-10 and 1.75×10-9, indicating that under circumstances of high temperature, long exposure time and low absolute pressure water was able to rapidly diffuse out of the tissue in the experimental domain. Lowering the absolute pressure of vacuum flask and increasing the exposure time led to the reduction in the activation energy of samples. The shrinkage coefficient was within the range of 79.91 to 84.92%. As such, the greatest total color difference was calculated between the color of raw and dried samples for those experiments with the largest increase in temperature, exposure time and a decrease in absolute pressure.

  12. Low-Cost, Rugged High-Vacuum System

    Science.gov (United States)

    Sorensen, Paul; Kline-Schoder, Robert

    2012-01-01

    A need exists for miniaturized, rugged, low-cost high-vacuum systems. Recent advances in sensor technology have led to the development of very small mass spectrometer detectors as well as other analytical instruments such as scanning electron microscopes. However, the vacuum systems to support these sensors remain large, heavy, and power-hungry. To meet this need, a miniaturized vacuum system was developed based on a very small, rugged, and inexpensive-to-manufacture molecular drag pump (MDP). The MDP is enabled by a miniature, very-high-speed (200,000 rpm), rugged, low-power, brushless DC motor optimized for wide temperature operation and long life. The key advantages of the pump are reduced cost and improved ruggedness compared to other mechanical hig-hvacuum pumps. The machining of the rotor and stators is very simple compared to that necessary to fabricate rotor and stator blades for other pump designs. Also, the symmetry of the rotor is such that dynamic balancing of the rotor will likely not be necessary. Finally, the number of parts in the unit is cut by nearly a factor of three over competing designs. The new pump forms the heart of a complete vacuum system optimized to support analytical instruments in terrestrial applications and on spacecraft and planetary landers. The MDP achieves high vacuum coupled to a ruggedized diaphragm rough pump. Instead of the relatively complicated rotor and stator blades used in turbomolecular pumps, the rotor in the MDP consists of a simple, smooth cylinder of aluminum. This will turn at approximately 200,000 rpm inside an outer stator housing. The pump stator comprises a cylindrical aluminum housing with one or more specially designed grooves that serve as flow channels. To minimize the length of the pump, the gas is forced down the flow channels of the outer stator to the base of the pump. The gas is then turned and pulled toward the top through a second set of channels cut into an inner stator housing that surrounds the

  13. Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure

    Science.gov (United States)

    Ishigaki, Yasuhito; Nakamura, Yuka; Oikawa, Yosaburo; Yano, Yasuhiro; Kuwabata, Susumu; Nakagawa, Hideaki; Tomosugi, Naohisa; Takegami, Tsutomu

    2012-01-01

    Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10−3 Pa vacuum pressure and electron beam irradiation with accelerated voltages (2–5 kV), many ticks remained alive and moved their legs. After 30-min observation, we removed the ticks from the SEM stage; they could walk actively under atmospheric pressure. When we tested 20 ticks (8 female adults and 12 nymphs), they survived for two days after SEM observation. These results indicate the resistance of ticks against SEM observation. Our second survival test showed that the electron beam, not vacuum conditions, results in tick death. Moreover, we describe the reaction of their legs to electron beam exposure. These findings open the new possibility of SEM observation of living organisms and showed the resistance of living ticks to vacuum condition in SEM. These data also indicate, for the first time, the usefulness of tick as a model system for biology under extreme condition. PMID:22431980

  14. Lipid oxidation and color changes of goose meat stored under vacuum and modified atmosphere conditions.

    Science.gov (United States)

    Orkusz, A; Haraf, G; Okruszek, A; Werenska-Sudnik, M

    2017-03-01

    The objective of the work was to investigate the color and lipid oxidation changes of goose breast meat packaged in vacuum and modified atmosphere (MA) conditions consisting of 80% O2, 20% CO2, and stored in refrigerated conditions at 4°C. Color stability was monitored by determining total heme pigments concentration; relative concentration of myoglobin, oxymyoglobin, and metmyoglobin; parameters of color L*, a*, b*, and sensory evaluation of the surface color. Lipid stability was measured by determining thiobarbituric acid reactive substances (TBARS). The samples were examined in 24 h after slaughter (unpacked muscles) and on d 4, 7, 9, 11 of storage (muscles packed in vacuum and in MA). Through the time of storage, samples packed in MA had higher TBARS values in comparison to the meat packed in vacuum. For samples packed in two types of atmospheres, the total pigments concentration decreased gradually within 11 d of storage. It was observed that relative metmyoglobin concentration increased whereas relative oxymyoglobin concentration decreased in total heme pigments in the MA stored muscle. The relative concentration of all three myoglobin forms sample packed in vacuum remained unchanged. The color parameters (L*, a*, b*) did not change for 11 d of storage for the vacuum packed meat. The value of the color parameter a* decreased and the value of the color parameters L* and b* increased in the samples packaged in MA. The data prove that if you store goose meat in MA (consisting of 80% O2, 20% CO2) or vacuum, the unchanged surface color is preserved for 9 and 11 day, respectively.Vacuum appears to be a better method as regards the maintaining of lipid stability in goose meat. © 2016 Poultry Science Association Inc.

  15. High-temperature vacuum distillation separation of plutonium waste salts

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, E. [Los Alamos National Lab., NM (United States)

    1996-10-01

    In this task, high-temperature vacuum distillation separation is being developed for residue sodium chloride-potassium chloride salts resulting from past pyrochemical processing of plutonium. This process has the potential of providing clean separation of the salt and the actinides with minimal amounts of secondary waste generation. The process could produce chloride salt that could be discarded as low-level waste (LLW) or low actinide content transuranic (TRU) waste, and a concentrated actinide oxide powder that would meet long-term storage standards (DOE-DTD-3013-94) until a final disposition option for all surplus plutonium is chosen.

  16. Microfabricated Millimeter-Wave High-Power Vacuum Electronic Amplifiers

    Science.gov (United States)

    2015-01-01

    colin.joye@nrl.navy.mil Microfabricated Millimeter-Wave High-Power Vacuum Electronic Amplifiers Figure 2. Results from the 220 GHz TWT . (a) Small signal...Completed tube under hot test. 220 GHz TWT Demonstration The 220 GHz TWT device was based on spare parts from a commercially available CPI VKY2444T G...existing parts, our TWT bested this COTS EIK performance by a factor of 12x in power and 50x in bandwidth for the same size, weight and prime power

  17. dc breakdown conditioning and breakdown rate of metals and metallic alloys under ultrahigh vacuum

    CERN Document Server

    Descoeudres, A; Calatroni, S; Taborelli, M; Wuensch, W

    2009-01-01

    RF accelerating structures of the Compact Linear Collider (CLIC) require a material capable of sustaining high electric field with a low breakdown rate and low induced damage. Because of the similarity of many aspects of DC and RF breakdown, a DC breakdown study is underway at CERN in order to test candidate materials and surface preparations, and have a better understanding of the breakdown mechanism under ultra-high vacuum in a simple setup. Conditioning speeds and breakdown fields of several metals and alloys have been measured. The average breakdown field after conditioning ranges from 100 MV/m for Al to 850 MV/m for stainless steel, and is around 170 MV/m for Cu which is the present base-line material for CLIC structures. The results indicate clearly that the breakdown field is limited by the cathode. The presence of a thin cuprous oxide film at the surface of copper electrodes significantly increases the breakdown field. On the other hand, the conditioning speed of Mo is improved by removing oxides at t...

  18. Gas and RRR distribution in high purity Niobium EB welded in Ultra-High Vacuum

    Science.gov (United States)

    Anakhov, S.; Singer, X.; Singer, W.; Wen, H.

    2006-05-01

    Electron beam (EB) welding in UHV (ultra-high vacuum, 10-5÷10-8 mbar) is applied in the standard fabrication of high gradient niobium superconducting radio frequency (SRF) cavities of TESLA design. The quality of EB welding is critical for cavity performance. Experimental data of gas content (H2, O2, N2) and RRR (residual resistivity ratio) measurements in niobium (Nb) welding seams are presented. EB welding in UHV conditions allow to preserve low gas content (1÷3 wt. ppm hydrogen and 5÷7 ppm oxygen and nitrogen), essential for high values of RRR — 350÷400 units. Gas content redistribution in the electron beam welded and heat affected region take place in the welding process. Correlation between gas solubility parameters, RRR and thermal conductivity are presented. Mechanisms of gas solubility in EB welding process are discussed.

  19. Oxidation and Reduction of Liquid SnPb (60/40) under Ambient and Vacuum Conditions

    DEFF Research Database (Denmark)

    Kuhmann, Jochen Friedrich; Maly, K.; Preuss, A.

    1998-01-01

    One of the most straightforward approaches to fluxless solder bonding is using vacuum conditions to prevent further oxidation and, where needed, to reduce solder oxides by the use of molecular hydrogen (H-2).(1-3) This study On oxidation and reduction of solder oxides on SnPb (60/40) is aimed to ...

  20. High-efficiency vacuum cleaners increase personal mite allergen exposure, but only slightly.

    Science.gov (United States)

    Gore, R B; Durrell, B; Bishop, S; Curbishley, L; Woodcock, A; Custovic, A

    2006-01-01

    High-efficiency particulate-arrest-filter vacuum cleaners are recommended to allergy sufferers although their use increases personal cat allergen exposure. We aimed to measure personal mite allergen exposure during vacuum cleaning by nasal air sampling and to compare exposures while vacuuming and emptying the vacuum cleaner bag. Five brand new high-efficiency vacuum cleaners were selected. An old, previously used vacuum cleaner with its original microfilter in situ was used as a control. Nasal air samples were taken prior to and during vacuum cleaning in 10 homes. Samples were processed by HALOgen assay. Personal mite and cat allergen exposure was measured as the dust compartments were emptied. There was an increase in personal mite allergen exposure with vacuum cleaning, which approached significance (P = 0.058). There was no difference between the high-efficiency vacuum cleaners and the control vacuum cleaner (P = 0.141). When the dust compartments were emptied, personal mite and cat allergen exposure increased (P vacuum cleaning in an area with mild to moderate mite allergen exposure is small. High-efficiency vacuum cleaners confer no benefit and cannot currently be recommended to allergy sufferers as a means of reducing personal mite allergen exposure.

  1. Temperature and rate of dehydration of major constituents of carbonaceous chondrites under vacuum conditions

    Science.gov (United States)

    Pohl, Leos; Britt, Daniel

    2017-10-01

    Some sub-types of carbonaceous chondrites contain a significant amount of hydrated minerals which produce specific absorption lines, typically due to the presence of hydroxyls. However, if these asteroids have come close enough to the Sun during their history, the high temperatures might have resulted in mineral decomposition and consequent loss of hydroxyl (or water) molecules in the surface layer and even to certain depths. Determination of the hydration state of phyllosilicates typically found on asteroids as well as the relative quantities of hydrated to desiccated phyllosilicates relies on experimental data - the temperature and rate of dehydration. Both dehydration temperature and rate depend on pressure. The rate also depends on the temperature. Experimentally determined phase curves for serpentine, that show for example decomposition of antigorite to forsterite and enstatite or talc and water, exist for GPa pressure levels. For antigorite, these temperatures span the range 500-750°C for pressures between 0.1 GPa and 8 GPa. However, these data are not suitable for vacuum environment found on asteroids; further, at lower pressures, the available data suggest a monotonically decreasing dehydration temperature with decreasing pressure. Also, the available data suggest dependence of both dehydration temperature and rate on the grain size distribution of the mineral. We have determined the temperature and rate of dehydration of the serpentine polymorphs antigorite, lizardite, cronstedtite, under high vacuum conditions and for various grain size distributions. The grain size distributions have been determined by particle analyzer and each sample source was also analyzed using X-Ray Diffraction.

  2. Materials Outgassing Rate Decay in Vacuum at Isothermal Conditions

    Science.gov (United States)

    Huang, Alvin Y.; Kastanas, George N.; Kramer, Leonard; Soares, Carlos E.; Mikatarian, Ronald R.

    2016-01-01

    As a laboratory for scientific research, the International Space Station has been in Low Earth Orbit for nearly 20 years and is expected to be on-orbit for another 10 years. The ISS has been maintaining a relatively pristine contamination environment for science payloads. Materials outgassing induced contamination is currently the dominant source for sensitive surfaces on ISS and modeling the outgassing rate decay over a 20 to 30 year period is challenging. Materials outgassing is described herein as a diffusion-reaction process using ASTM E 1559 rate data. The observation of -1/2 (diffusion) or non-integers (reaction limited) as rate decay exponents for common ISS materials indicate classical reaction kinetics is unsatisfactory in modeling materials outgassing. Non-randomness of reactant concentrations at the interface is the source of this deviation from classical reaction kinetics. A diffusion limited decay was adopted as the result of the correlation of the contaminant layer thicknesses on returned ISS hardware, the existence of high outgassing silicone exhibiting near diffusion limited decay, and the confirmation of non-depleted material after ten years in the Low Earth Orbit.Keywords: Materials Outgassing, ASTM E 1559, Reaction Kinetics, Diffusion, Space Environments Effects, Contamination

  3. Advances in high voltage insulation and arc interruption in SF6 and vacuum

    CERN Document Server

    Maller, V N

    1982-01-01

    Advances in High Voltage Insulation and Arc Interruption in SF6 and Vacuum deals with high voltage breakdown and arc extinction in sulfur hexafluoride (SF6) and high vacuum, with special emphasis on the application of these insulating media in high voltage power apparatus and devices. The design and developmental aspects of various high voltage power apparatus using SF6 and high vacuum are highlighted. This book is comprised of eight chapters and opens with a discussion on electrical discharges in SF6 and high vacuum, along with the properties and handling of SF6 gas. The following chapters fo

  4. Micro-damage propagation in ultra-high vacuum seals

    CERN Document Server

    Lutkiewicz, P; Garion, C

    2010-01-01

    The paper addresses a fundamental problem of tightness of ultra-high vacuum systems (UHV) at cryogenic temperatures in the light of continuum damage mechanics (CDM). The problem of indentation of a rigid punch into an elastic-plastic half-space is investigated based on rate independent plasticity with mixed kinematic and isotropic hardening. The micro-damage fields are modeled by using an anisotropic approach with a kinetic law of damage evolution suitable for ductile materials and cryogenic temperatures. The model has been experimentally validated and the results are used to predict the onset of macro-cracking (loss of tightness) and the corresponding load (contact pressure). The algorithm is applied in the design of UHV systems for particle accelerators. (C) 2009 Published by Elsevier Ltd.

  5. A technique for high recoveries from vacuum distillations

    Directory of Open Access Journals (Sweden)

    Richard F. Langler

    2007-08-01

    Full Text Available The design and use of a novel apparatus for a variant of vacuum distillation is described. Relative to a conventional device, the apparatus/technique described permits superior recovery of multigram quantities of moderately volatile liquids from vacuum distillations.

  6. Adsorption of hydrogen fluoride onto activated carbon under vacuum conditions: Equilibrium, kinetic and thermodynamic investigations

    OpenAIRE

    Bahrami Hussein; Safdari Jaber; Moosavian Ali Mohammad; Torab-Mostaedi Meisam

    2012-01-01

    In this study, the adsorption of HF gas by three types of activated carbon has been investigated under vacuum condition. The effects of experimental parameters such as initial pressure of the HF gas, contact time and temperature on adsorption process have been investigated. The results showed that the adsorption of the HF gas onto activated carbon increased by increasing initial pressure of gas, while it decreased with increase in temperature. The Freundlich isotherm model fitted the eq...

  7. Avoiding vacuum arcs in high gradient normal conducting RF structures

    CERN Document Server

    Sjøbæk, Kyrre Ness; Adli, Erik; Grudiev, Alexej; Wuensch, Walter

    In order to build the Compact LInear Collider (CLIC), accelerating structures reaching extremely high accelerating gradients are needed. Such structures have been built and tested using normal-conducting copper, powered by X-band RF power and reaching gradients of 100 MV/m and above. One phenomenon that must be avoided in order to reliably reach such gradients, is vacuum arcs or “breakdowns”. This can be accomplished by carefully designing the structure geometry such that high surface fields and large local power flows are avoided. The research presented in this thesis presents a method for optimizing the geometry of accelerating structures so that these breakdowns are made less likely, allowing the structure to operate reliably at high gradients. This was done primarily based on a phenomenological scaling model, which predicted the maximum gradient as a function of the break down rate, pulse length, and field distribution in the structure. The model is written in such a way that it allows direct comparis...

  8. Jets with ALICE: from vacuum to high-temperature QCD

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    ALICE measures jets in pp, p-Pb and Pb-Pb collisions to study modifications of the jet fragmentation due to cold nuclear and hot QCD matter. In pp collisions ALICE has measured inclusive jet yields, the ratio of yields with different resolution R, a variety of jet shapes and the semi-inclusive rate of jets recoiling against a high transverse momentum hadron trigger. These measurements are compared to NLO calculations including hadronization corrections and to MC models. Jets in pp are primarily conceived as a vacuum reference for jet observables in p-Pb and Pb-Pb collisions. In p-Pb collisions ALICE explores cold nuclear matter effects on jet yields, jet fragmentation and dijet acoplanarity. The hot and dense medium created in heavy-ion collisions is expected to modify the fragmentation of high energy partonic projectiles leading to changes in the energy and structure of the reconstructed jets with respect to pp jets. The study of modified jets aims at understanding the detailed mechanisms of in-medium energy...

  9. A Versatile High-Vacuum Cryo-transfer System for Cryo-microscopy and Analytics

    Science.gov (United States)

    Tacke, Sebastian; Krzyzanek, Vladislav; Nüsse, Harald; Wepf, Roger Albert; Klingauf, Jürgen; Reichelt, Rudolf

    2016-01-01

    Cryogenic microscopy methods have gained increasing popularity, as they offer an unaltered view on the architecture of biological specimens. As a prerequisite, samples must be handled under cryogenic conditions below their recrystallization temperature, and contamination during sample transfer and handling must be prevented. We present a high-vacuum cryo-transfer system that streamlines the entire handling of frozen-hydrated samples from the vitrification process to low temperature imaging for scanning transmission electron microscopy and transmission electron microscopy. A template for cryo-electron microscopy and multimodal cryo-imaging approaches with numerous sample transfer steps is presented. PMID:26910419

  10. Ultra-high vacuum compatible induction-heated rod casting furnace

    OpenAIRE

    Bauer, Andreas; Neubauer, Andreas; Münzer, Wolfgang; Regnat, Alexander; Benka, Georg; Meven, Martin; Pedersen, Björn; Pfleiderer, Christian

    2016-01-01

    We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of the mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is a...

  11. A vacuum tube vee-trough collector for solar heating and air conditioning applications

    Science.gov (United States)

    Selcuk, M. K.

    1978-01-01

    An analysis is conducted of the performance of a vee-trough vacuum tube collector proposed for use in solar heating and cooling applications. The vee-trough reflector is a triangular sectioned, flat surfaced reflector, whose axis is laid in the East-West direction. A vacuum tube receiver placed at the bottom of the vee-trough collects solar heat most efficiently since convection is completely eliminated. Radiation losses are reduced by use of selective coatings on the absorber. Owing to its high temperature capabilities (300-400 F), the proposed scheme could also be used for power generation applications in combination with an organic Rankine conversion system. It is especially recommended for unattended pumping stations since the reflectors only require reversal once every six months.

  12. High-Speed Automated Tester for Vacuum Chamber Feedthrough Connectors and Cables

    Science.gov (United States)

    Swope, Robert H.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    The Goddard Space Flight Center's thermal vacuum laboratory has developed a high-speed automated system for testing the integrity of 37-pin MIL-C-5015 cylindrical electrical feedthrough connectors used on penetration plates of thermal vacuum chambers. The system consists of a desktop PC driving a data acquisition front end. The latter measures the resistance through each pin of the connector and the resistance from each pin to all other pins and the connector shell. In addition to identifying unacceptable feedthroughs, the system is also used for testing cables. In the special case of Type T thermocouples (used almost exclusively at the lab), the difference in resistance between the copper and constantan wires provides positive proof of accidentally reversed connector wiring. Data acquisition time to completely test a cable or feedthrough connector is less than thirty seconds. The system provides a hardcopy printout of the resistance readings. Connectors or cables with fewer wires are tested using simple adapter cables. Initial tests indicate that the performance of a given feedthrough connector can be predicted on the basis of measured resistance readings, reducing ongoing cost of connector replacement. The opportunity to positively certify the integrity of cables, cable connectors and feedthroughs before the start of a thermal vacuum test minimizes the likelihood of a circuit problem that would require returning the chamber to ambient conditions for repair. This system has two principal advantages for the Goddard thermal vacuum laboratory. Its only significant cost was the labor to fabricate the test cable and shorting cable -- about 40 man-hours total. The system was built around a computer and data acquisition unit that were already on hand. The second advantage is that it very quickly tests both of the parameters that are essential.

  13. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    Science.gov (United States)

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  14. Ultra-high vacuum compatible induction-heated rod casting furnace

    Science.gov (United States)

    Bauer, A.; Neubauer, A.; Münzer, W.; Regnat, A.; Benka, G.; Meven, M.; Pedersen, B.; Pfleiderer, C.

    2016-06-01

    We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of the mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bars. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely, the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb.

  15. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: a modular vacuum ultraviolet source.

    Science.gov (United States)

    Roberts, F Sloan; Anderson, Scott L

    2013-12-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

  16. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    Energy Technology Data Exchange (ETDEWEB)

    Sloan Roberts, F.; Anderson, Scott L. [Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 (United States)

    2013-12-15

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry.

  17. Design and performance of vacuum system for high heat flux test facility

    Science.gov (United States)

    Swamy Kidambi, Rajamannar; Mokaria, Prakash; Khirwadkar, Samir; Belsare, Sunil; Khan, M. S.; Patel, Tushar; Krishnan, Deepu S.

    2017-04-01

    High heat flux test facility (HHFTF) at IPR is used for testing thermal performance of plasma facing materials or components. It consists of various subsystems like vacuum system, high power electron beam system, diagnostic and calibration system, data acquisition and control system and high pressure high temperature water circulation system. Vacuum system consists of large D-shaped chamber, target handling system, pumping systems and support structure. The net volume of vacuum chamber is 5 m3 was maintained at the base pressure of the order of 10-6 mbar for operation of electron gun with minimum beam diameter which is achieved with turbo-molecular pump (TMP) and cryo pump. A variable conductance gate valve is used for maintaining required vacuum in the chamber. Initial pumping of the chamber was carried out by using suitable rotary and root pumps. PXI and PLC based faster real time data acquisition and control system is implemented for performing the various operations like remote operation, online vacuum data measurements, display and status indication of all vacuum equipments. This paper describes in detail the design and implementation of various vacuum system for HHFTF.

  18. New model for colour kinetics of plum under infrared vacuum condition and microwave drying.

    Science.gov (United States)

    Chayjan, Reza Amiri; Alaei, Behnam

    2016-01-01

    Quality of dried foods is affected by the drying method and physiochemical changes in tissue. The drying method affects properties such as colour. The colour of processed food is one of the most important quality indices and plays a determinant role in consumer acceptability of food materials and the processing method. The colour of food materials can be used as an indirect factor to determine changes in quality, since it is simpler and faster than chemical methods. The study focused on the kinetics of colour changes of plum slices, under infrared vacuum and microwave conditions. Drying the samples was implemented at the absolute pressures of 20 and 60 kPa, drying temperatures of 50 and 60°C and microwave power of 90, 270, 450 and 630 W. Colour changes were quantified by the tri-stimulus L* (whiteness/darkness), a* (redness/greenness) and b* (yellowness/blueness) model, which is an international standard for color measurement developed by the Commission Internationale d'Eclairage (CIE). These values were also used to calculate total colour change (∆E), chroma, hue angle, and browning index (BI). A new model was used for mathematical modelling of colour change kinetics. The drying process changed the colour parameters of L*, a*, and b*, causing a colour shift toward the darker region. The values of L* and hue angle decreased, whereas the values of a*, b*, ∆E, chroma and browning index increased during exposure to infrared vacuum conditions and microwave drying. Comparing the results obtained using the new model with two conventional models of zero-order and first-order kinetics indicated that the new model presented more compatibility with the data of colour kinetics for all colour parameters and drying conditions. All kinetic changes in colour parameters can be explained by the new model presented in this study. The hybrid drying system included infrared vacuum conditions and microwave power for initial slow drying of plum slices and provided the desired

  19. Development of precision numerical controlled high vacuum electron beam welding machine

    CERN Document Server

    Li Shao Lin

    2002-01-01

    The structure, main technical parameters and characteristics of the precision numerical controlled high vacuum electron beam welding machine are introduced. The design principle, some features and solutions to some key technique problems of this new type machine are described

  20. Cooling the Motion of Diamond Nanocrystals in a Magneto-Gravitational Trap in High Vacuum

    National Research Council Canada - National Science Library

    Hsu, Jen-Feng; Ji, Peng; Lewandowski, Charles W; D'Urso, Brian

    2016-01-01

    ... with currently available materials. Here, we study an alternative magneto-gravitational trap for diamagnetic particles, such as diamond nanocrystals, with stable levitation from atmospheric pressure to high vacuum...

  1. Very Low-Cost, Rugged, High-Vacuum System for Mass Spectrometers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA, DoD, DHS, and commercial industry have a pressing need for miniaturized, rugged, low-cost high-vacuum systems. Recent advances in sensor technology at NASA and...

  2. Very Low-Cost, Rugged, High-Vacuum System for Mass Spectrometers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA, the DoD, DHS, and commercial industry have a pressing need for miniaturized, rugged, low-cost, high vacuum systems. Recent advances in sensor technology at...

  3. Surface Effects and Challenges for Application of Piezoelectric Langasite Substrates in Surface Acoustic Wave Devices Caused by High Temperature Annealing under High Vacuum

    Directory of Open Access Journals (Sweden)

    Marietta Seifert

    2015-12-01

    Full Text Available Substrate materials that are high-temperature stable are essential for sensor devices which are applied at high temperatures. Although langasite is suggested as such a material, severe O and Ga diffusion into an O-affine deposited film was observed during annealing at high temperatures under vacuum conditions, leading to a damage of the metallization as well as a change of the properties of the substrate and finally to a failure of the device. Therefore, annealing of bare LGS (La 3 Ga 5 SiO 14 substrates at 800 ∘ C under high vacuum conditions is performed to analyze whether this pretreatment improves the suitability and stability of this material for high temperature applications in vacuum. To reveal the influence of the pretreatment on the subsequently deposited metallization, RuAl thin films are used as they are known to oxidize on LGS at high temperatures. A local study of the pretreated and metallized substrates using transmission electron microscopy reveals strong modification of the substrate surface. Micro cracks are visible. The composition of the substrate is strongly altered at those regions. Severe challenges for the application of LGS substrates under high-temperature vacuum conditions arise from these substrate damages, revealing that the pretreatment does not improve the applicability.

  4. Modeling of acetylene pyrolysis under steel vacuum carburizing conditions in a tubular flow reactor.

    Science.gov (United States)

    Khan, Rafi Ullah; Bajohr, Siegfried; Graf, Frank; Reimert, Rainer

    2007-03-02

    In the present work, the pyrolysis of acetylene was studied under steel vacuum carburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from 650 degrees C to 1050 degrees C. The partial pressure of acetylene in the feed mixture was 10 and 20 mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressure of the mixture was 1.6 bar. A kinetic mechanism which consists of seven species and nine reactions has been used in the commercial computational fluid dynamics (CFD) software Fluent. The species transport and reaction model of Fluent was used in the simulations. A comparison of simulated and experimental results is presented in this paper.

  5. LHCb: Design of a Highly Optimised Vacuum Chamber Support for the LHCb Experiment

    CERN Multimedia

    Leduc, L; Veness, R

    2011-01-01

    The beam vacuum chamber in the LHCb experimental area passes through the centre of a large aperture dipole magnet. The vacuum chamber and all its support systems lie in the acceptance of the detector, so must be highly optimised for transparency to particles. As part of the upgrade programme for the LHCb vacuum system, the support system has been re-designed using advanced lightweight materials. In this paper we discuss the physics motivation for the modifications, the criteria for the selection of materials and tests performed to qualify them for the particular environment of a particle physics experiment. We also present the design of the re-optimised support system.

  6. Search for Z′, vacuum (instability and hints of high-energy structures

    Directory of Open Access Journals (Sweden)

    Accomando Elena

    2016-01-01

    Full Text Available We study the high-energy behaviour of a class of anomaly-free abelian extensions of the Standard Model. We focus on the interplay among the phenomenological characterisation of the model and the use of precise renormalisation group methods. Using as boundary conditions regions of the parameter space at the verge of current LHC probe, interesting unification patterns emerge linked to thresholds belonging to a SO(10 grand unification theory (GUT. We stress how the evolution of the mixing between the two abelian factors may provide a valuable tool to address the candidate high-energy embedding. The emerging unification scenarios are then challenged to be perturbative and to allow for a stable vacuum.

  7. 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...

  8. UPGRADE OF RHIC VACUUM SYSTEMS FOR HIGH LUMINOSITY OPERATION.

    Energy Technology Data Exchange (ETDEWEB)

    HSEUH, H.C.; MAPES, M.; SMART, L.A.; TODD, R.; WEISS, D.

    2005-05-16

    With increasing ion beam intensity during recent RHIC operations, rapid pressure rises of several decades were observed at most warm 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 and anti-grazing ridges have been implemented. Several hundred meters of NEG coated beam pipes have been installed and activated. Vacuum monitoring and logging were enhanced. Preventive 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 and summarized.

  9. Vacuum-integrated electrospray deposition for highly reliable polymer thin film.

    Science.gov (United States)

    Park, Soohyung; Lee, Younjoo; Yi, Yeonjin

    2012-10-01

    Vacuum electrospray deposition (ESD) equipment was designed to prepare polymer thin films. The polymer solution can be injected directly into vacuum system through multi-stage pumping line, so that the solvent residues and ambient contaminants are highly reduced. To test the performance of ESD system, we fabricated organic photovoltaic cells (OPVCs) by injecting polymer solution directly onto the substrate inside a high vacuum chamber. The OPVC fabricated has the structure of Al∕P3HT:PCBM∕PEDOT:PSS∕ITO and was optimized by varying the speed of solution injection and concentration of the solution. The power conversion efficiency (PCE) of the optimized OPVC is 3.14% under AM 1.5G irradiation without any buffer layer at the cathode side. To test the advantages of the vacuum ESD, we exposed the device to atmosphere between the deposition steps of the active layer and cathode. This showed that the PCE of the vacuum processed device is 24% higher than that of the air exposed device and confirms the advantages of the vacuum prepared polymer film for high performance devices.

  10. Conditioning of the vacuum chamber of the Tokamak Novillo; Acondicionamiento de la camara de vacio del Tokamak Novillo

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-03-15

    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{sup -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)

  11. Mechanical behaviour of vacuum chambers and beam screens under quench conditions in dipole and quadrupole fields

    CERN Document Server

    Rathjen, C

    2002-01-01

    A method based on analytical formulas is described to calculate bending moments, stresses, and deformations of vacuum chambers and beam screens in dipole and in quadrupole fields during a magnet quench. Solutions are given for circular and racetrack shaped structures. Without the need of time consuming calculations the solutions enable a quick design and verification of vacuum chambers and beam screens.

  12. 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.

  13. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap.

    Science.gov (United States)

    Nikolaev, A G; Savkin, K P; Oks, E M; Vizir, A V; Yushkov, G Yu; Vodopyanov, A V; Izotov, I V; Mansfeld, D A

    2012-02-01

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap--axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  14. 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.

  15. The effect of excitation wavelength on plasma spectrum of metals in vacuum condition

    Science.gov (United States)

    Hidayah, A. N.; Suliyanti, M. M.; Isnaeni

    2017-04-01

    Pure metals Aluminum (Al), Copper (Cu) and Brass (CuZn) have been detected using laser-induced plasma spectroscopy technique using nanosecond laser. A Q-switch pulsed Nd:YAG laser operating at infrared (1064 nm), visible (532 nm) and ultraviolet (355 nm) wavelengths have been used. The energy laser used was 12 mJ and the experiment was carried out in vacuum condition (5 Torr). The plasma generated by a focused Nd:YAG laser beam was detected by a spectrometer to identify trace elements quantitatively. The result of quantitative trace element of pure metals at three different wavelengths gave the different results. Al metal excited by 355 nm, 532 nm and 1064 nm wavelengths has 5, 2 and 13 Al emission peaks, respectively. Whereas the analysis of Cu showed 5, 7 and 6 emission peaks upon excitation by 355 nm, 532 nm and 1064 nm wavelengths, respectively. Finally, CuZn metal produced 7 Cu lines and 2 Zn lines upon excitation by 355 nm wavelength, 8 Cu lines and 1 Zn line when excited by 532 nm wavelength, and 8 Cu lines and 3 Zn lines when excited by 1064 nm wavelength.

  16. Improvised Vacuum-Assisted Closure for severe neck infection in poorly equipped conditions.

    Science.gov (United States)

    Adam, S; Sama, H D; Chossegros, C; Bouassalo, M K; Akpoto, M Y; Kpemissi, E

    2017-06-01

    Dental infections are common and are mainly due to dental caries. When left untreated, these infections can lead to severe life-threatening sepsis. The authors reported a case of a severe odontogenic deep neck space infection in a 54-year-old male. The patient was a heavy smoker with incidentally discovered diabetes. He was successfully treated by surgical drainage combined with an improvised Vacuum-Assisted Closure (VAC) system. The results of surgical drainage followed by insertion of an improvised VAC system were spectacular. The abscess resolved in response to dual-agent antibiotic therapy on day 17 and blood glucose control was achieved with insulin. Full-thickness skin graft was performed to repair the necrotic zone of the neck. The use of VAC can be a valuable alternative to conventional dressings and hyperbaric oxygen therapy in poorly equipped conditions. Public awareness campaigns remain the most effective form of prevention against these odontogenic infections. Copyright © 2017. Published by Elsevier Masson SAS.

  17. Comparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere and vacuum conditions

    Science.gov (United States)

    Freeman, J. R.; Harilal, S. S.; Diwakar, P. K.; Verhoff, B.; Hassanein, A.

    2013-09-01

    In this study we examine the emission from brass plasma produced by ns and fs laser ablation under both vacuum and atmosphere environments using identical laser fluences in order to better understand the differences in emission features and plasma dynamics. Optical emission spectra show increased continuum and emission from lower-charged ions for ns laser-produced plasma (LPP), while fs plasma emission spectra show emission primarily from excited neutral species with negligible continuum. Plasma excitation temperature and electron density as a function of time show similar trends for both lasers, though fs LPP expansion appears to be approximately two times faster than ns LPP expansion for the conditions studied. Confinement by the ambient gas is shown to significantly enhance and maintain plasma temperature and density and hence, emission, at later times. ICCD images of plasma expansion showed a broader angular distribution for ns LPP, but narrower angular distribution for fs LPP. Images also confirm the significant effect that the ambient environment has in confining plume expansion.

  18. Comparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere and vacuum conditions

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, J.R., E-mail: freemaj@purdue.edu; Harilal, S.S., E-mail: sharilal@purdue.edu; Diwakar, P.K., E-mail: pdiwakar@purdue.edu; Verhoff, B., E-mail: bverhoff@purdue.edu; Hassanein, A., E-mail: hassanein@purdue.edu

    2013-09-01

    In this study we examine the emission from brass plasma produced by ns and fs laser ablation under both vacuum and atmosphere environments using identical laser fluences in order to better understand the differences in emission features and plasma dynamics. Optical emission spectra show increased continuum and emission from lower-charged ions for ns laser-produced plasma (LPP), while fs plasma emission spectra show emission primarily from excited neutral species with negligible continuum. Plasma excitation temperature and electron density as a function of time show similar trends for both lasers, though fs LPP expansion appears to be approximately two times faster than ns LPP expansion for the conditions studied. Confinement by the ambient gas is shown to significantly enhance and maintain plasma temperature and density and hence, emission, at later times. ICCD images of plasma expansion showed a broader angular distribution for ns LPP, but narrower angular distribution for fs LPP. Images also confirm the significant effect that the ambient environment has in confining plume expansion. - Highlights: • Emission from ns and fs LIBS plumes are compared under different pressure environments. • Ablation mechanisms for each laser are used to explain different emission features. • Ambient pressure plays a critical role in plume temperature and density evolution. • Visible emission from fs LIBS plume is almost entirely from neutral species. • Spectra collection time delay is shown to be very important in improving S/N and S/B.

  19. A vacuum-sealed, gigawatt-class, repetitively pulsed high-power microwave source

    Science.gov (United States)

    Xun, Tao; Fan, Yu-wei; Yang, Han-wu; Zhang, Zi-cheng; Chen, Dong-qun; Zhang, Jian-de

    2017-06-01

    A compact L-band sealed-tube magnetically insulated transmission line oscillator (MILO) has been developed that does not require bulky external vacuum pump for repetitive operations. This device with a ceramic insulated vacuum interface, a carbon fiber array cathode, and non-evaporable getters has a base vacuum pressure in the low 10-6 Pa range. A dynamic 3-D Monte-Carlo model for the molecular flow movement and collision was setup for the MILO chamber. The pulse desorption, gas evolution, and pressure distribution were exactly simulated. In the 5 Hz repetition rate experiments, using a 600 kV diode voltage and 48 kA beam current, the average radiated microwave power for 25 shots is about 3.4 GW in 45 ns pulse duration. The maximum equilibrium pressure is below 4.0 × 10-2 Pa, and no pulse shortening limitations are observed during the repetitive test in the sealed-tube condition.

  20. Thermal conductivity of aerogel blanket insulation under cryogenic-vacuum conditions in different gas environments

    Science.gov (United States)

    E Fesmire, J.; Ancipink, J. B.; Swanger, A. M.; White, S.; Yarbrough, D.

    2017-12-01

    Thermal conductivity of low-density materials in thermal insulation systems varies dramatically with the environment: cold vacuum pressure, residual gas composition, and boundary temperatures. Using a reference material of aerogel composite blanket (reinforcement fibers surrounded by silica aerogel), an experimental basis for the physical heat transmission model of aerogel composites and other low-density, porous materials is suggested. Cryogenic-vacuum testing between the boundary temperatures of 78 K and 293 K is performed using a one meter cylindrical, absolute heat flow calorimeter with an aerogel blanket specimen exposed to different gas environments of nitrogen, helium, argon, or CO2. Cold vacuum pressures include the full range from 1×10-5 torr to 760 torr. The soft vacuum region, from about 0.1 torr to 10 torr, is complex and difficult to model because all modes of heat transfer – solid conduction, radiation, gas conduction, and convection – are significant contributors to the total heat flow. Therefore, the soft vacuum tests are emphasized for both heat transfer analysis and practical thermal data. Results for the aerogel composite blanket are analyzed and compared to data for its component materials. With the new thermal conductivity data, future applications of aerogel-based insulation systems are also surveyed. These include Mars exploration and surface systems in the 5 torr CO2 environment, field joints for vacuum-jacketed cryogenic piping systems, common bulkhead panels for cryogenic tanks on space launch vehicles, and liquid hydrogen cryofuel systems with helium purged conduits or enclosures.

  1. Experimental observation of high-voltage, low-current vacuum arcs

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R.Y.; Puzanov, S.V.; Yashnov, Y.M. [Scientific-Research Inst. Titan, Moscow (Russian Federation)

    1995-12-01

    A poorly explored type of discharge has been investigated in high vacuum (10{sup {minus}7} to 10{sup {minus}6} torr), with a DC high voltage across 0.2- to 0.8-mm gaps. The discharge has been found to be quite different from other widely known types of vacuum and gas discharges by the combination of its voltage-current characteristics (hyperbola-type), source and carriers of current (mostly electrons), and spatial potential distribution (a considerable electric field across the gap and a steep potential fall near the cathode).

  2. Ultrasonic Spray Drying vs High Vacuum and Microwaves Technology for Blueberries

    Science.gov (United States)

    Candia-Muñoz, N.; Ramirez-Bunster, M.; Vargas-Hernández, Y.; Gaete-Garretón, L.

    Interest in high quality foods: good taste and a high content of nutrients with healthy beneficial effects are increasing. Fruits have good properties but, they are lost because the oxidation process, additionally, for different reasons a 40% of harvested fruit are lost. To conserve the fruit properties an ultrasonic assisted spray dryer was developed and tested, comparing its results with microwave-vacuum drying technology. Results did shown taste, color, smell, particle shape and size distribution better than the conventional one. The antioxidants conservation were quite good except in the anthocyanins, in which the microwave and vacuum technology shown best results.

  3. Effect of osmotic dehydration and vacuum-frying parameters to produce high-quality mango chips.

    Science.gov (United States)

    Nunes, Yolanda; Moreira, Rosana G

    2009-09-01

    Mango (Mangifera indica L.) is a fruit rich in flavor and nutritional values, which is an excellent candidate for producing chips. The objective of this study was to develop high-quality mango chips using vacuum frying. Mango ("Tommy Atkins") slices were pretreated with different maltodextrin concentrations (40, 50, and 65, w/v), osmotic dehydration times (45, 60, and 70 min), and solution temperatures (22 and 40 degrees C). Pretreated slices were vacuum fried at 120, 130, and 138 degrees C and product quality attributes (oil content, texture, color, carotenoid content) determined. The effect of frying temperatures at optimum osmotic dehydration times (65 [w/v] at 40 degrees C) was assessed. All samples were acceptable (scores > 5) to consumer panelists. The best mango chips were those pretreated with 65 (w/v) concentration for 60 min and vacuum fried at 120 degrees C. Mango chips under atmospheric frying had less carotenoid retention (32%) than those under vacuum frying (up to 65%). These results may help further optimize vacuum-frying processing of high-quality fruit-based snacks.

  4. Ethanol production from food waste at high solids content with vacuum recovery technology.

    Science.gov (United States)

    Huang, Haibo; Qureshi, Nasib; Chen, Ming-Hsu; Liu, Wei; Singh, Vijay

    2015-03-18

    Ethanol production from food wastes does not only solve environmental issues but also provides renewable biofuels. This study investigated the feasibility of producing ethanol from food wastes at high solids content (35%, w/w). A vacuum recovery system was developed and applied to remove ethanol from fermentation broth to reduce yeast ethanol inhibition. A high concentration of ethanol (144 g/L) was produced by the conventional fermentation of food waste without a vacuum recovery system. When the vacuum recovery is applied to the fermentation process, the ethanol concentration in the fermentation broth was controlled below 100 g/L, thus reducing yeast ethanol inhibition. At the end of the conventional fermentation, the residual glucose in the fermentation broth was 5.7 g/L, indicating incomplete utilization of glucose, while the vacuum fermentation allowed for complete utilization of glucose. The ethanol yield for the vacuum fermentation was found to be 358 g/kg of food waste (dry basis), higher than that for the conventional fermentation at 327 g/kg of food waste (dry basis).

  5. High-efficiency particulate arrest-filter vacuum cleaners increase personal cat allergen exposure in homes with cats.

    Science.gov (United States)

    Gore, Robin B; Durrell, Bethan; Bishop, Sophie; Curbishley, Lisa; Woodcock, Ashley; Custovic, Adnan

    2003-04-01

    On the basis of experimental chamber studies, vacuum cleaners with double-thickness bags and integral high-efficiency particulate arrest (HEPA) air filters are claimed to reduce airborne allergen levels and are currently recommended to allergic patients. The objective of this study was to investigate the effect of vacuum cleaning on personal inhaled cat allergen exposure in homes with cats. Five unused new vacuum cleaners were compared with an old non-HEPA filter vacuum cleaner. Each vacuum cleaner was tested in an experimental chamber and in 5 homes with cats. Inhaled cat allergen was measured by nasal air sampling. New vacuum cleaners failed to leak any allergen in the experimental chamber. There was a significant increase in inhaled cat allergen during vacuum cleaning in homes (F = 48.39, df = 1.4, P =.002) with no difference between the old vacuum cleaner and the unused new vacuum cleaners (5-fold and 3-fold increase compared to baseline, respectively; F = 0.005, df = 1.4, P =.95). The use of new HEPA-filter vacuum cleaners increases inhaled cat allergen in homes with cats. The use of HEPA-filter modern vacuum cleaners to reduce pet allergen exposure in the homes of pet owners should not be justified merely on the basis of experimental chamber data.

  6. Cleaning efficacy of high-efficiency particulate air-filtered vacuuming and "dry steam" cleaning on carpet.

    Science.gov (United States)

    Yiin, Lih-Ming; Yu, Chang Ho; Ashley, Peter; Rhoads, George

    2008-02-01

    Previous studies for lead exposure reduction have indicated the difficulty in reducing surface contamination of carpets with the use of regular vacuum cleaners. To find a solution, a household vacuum cleaner equipped with a high-efficiency particulate air (HEPA) filter and a dust finder indicator, and a "dry steam" cleaner previously reported effective in reducing dust mite allergens in carpets and mattresses were tested for effectiveness in reducing lead dust in carpets. Fifty homes of lead-exposed children were tested in New Jersey. A selected carpet in the living area of each home was tested with two interventions: half was cleaned by HEPA vacuuming twice (VAC-VAC) and the other half by dry steaming between the two HEPA vacuumings (VAC-DSC-VAC). Wipe and vacuum samples, representing surface dust and total dust collections, respectively, were taken before and after cleaning. The wipe and vacuum sample data indicated that both cleaning methods substantially reduced dust lead levels (p vacuum sampling (p = 0.072). A subset of sample data collected before repeat vacuuming (VAC-DSC) suggested that repeat vacuuming after dry steam cleaning is unnecessary. In summary, slow and steady HEPA vacuuming with the help of a dust finder indicator reduces surface and overall lead dust in carpets, and dry steam cleaning further reduces surface lead contamination as compared with HEPA vacuuming alone.

  7. Ethanol production from food waste at high solid contents with vacuum recovery technology

    Science.gov (United States)

    Ethanol production from food wastes does not only solve the environmental issues but also provide renewable biofuel to partially substitute fossil fuels. This study investigated the feasibility of utilization of food wastes for producing ethanol at high solid contents (35%, w/w). Vacuum recovery sys...

  8. Modeling the growth of Lactobacillus viridescens under non-isothermal conditions in vacuum-packed sliced ham.

    Science.gov (United States)

    Silva, Nathália Buss da; Longhi, Daniel Angelo; Martins, Wiaslan Figueiredo; Laurindo, João Borges; Aragão, Gláucia Maria Falcão de; Carciofi, Bruno Augusto Mattar

    2017-01-02

    Lactic acid bacteria (LAB) are responsible for spoiling vacuum-packed meat products, such as ham. Since the temperature is the main factor affecting the microbial dynamic, the use of mathematical models describing the microbial behavior into a non-isothermal environment can be very useful for predicting food shelf life. In this study, the growth of Lactobacillus viridescens was measured in vacuum-packed sliced ham under non-isothermal conditions, and the predictive ability of primary (Baranyi and Roberts, 1994) and secondary (Square Root) models were assessed using parameters estimated in MRS culture medium under isothermal conditions (between 4 and 30°C). Fresh ham piece was sterilized, sliced, inoculated, vacuum-packed, and stored in a temperature-controlled incubator at five different non-isothermal conditions (between 4 and 25°C) and one isothermal condition (8°C). The mathematical models obtained in MRS medium were assessed by comparing predicted values with L. viridescens growth data in vacuum-packed ham. Its predictive ability was assessed through statistical indexes, with good results (bias factor between 0.95 and 1.03; accuracy factor between 1.04 and 1.07, and RMSE between 0.76 and 1.33), especially in increasing temperature, which predictions were safe. The model parameters obtained from isothermal growth data in MRS medium enabled to estimate the shelf life of a commercial ham under non-isothermal conditions in the temperature range analyzed. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. A high precision flat crystal spectrometer compatible for ultra-high vacuum light source

    Science.gov (United States)

    Yang, Y.; Xiao, J.; Lu, D.; Shen, Y.; Yao, K.; Chen, C.; Hutton, R.; Zou, Y.

    2017-11-01

    We report on a flat crystal spectrometer (FCS) featuring a differently pumped rotary feedthrough and double detectors connected to a crystal chamber by extendable bellows built at the Shanghai EBIT Laboratory. It was designed to overcome defects such as oil contamination, little distance from the detector to the crystal and others of an early FCS equipped at the same laboratory, but still keeps a large detectable angle range of detectors and brings new features and functions such as the Bond method measurement and double-crystal measurement which are based on the two-detector and large bellow design. This new FCS could cover an energy range of measurable photons from 570 eV to 10 keV and reach a vacuum better than 6 × 10-10 Torr and thus is compatible for coupling directly to ultra-high vacuum light sources. Off-line tests of the FCS were undertaken where Kα x-rays from solid titanium were measured and analyzed. Measurements of transitions in He-like argon ions were performed when the spectrometer was directly connected to Shanghai EBIT, and the width of the x-ray source was monitored simultaneously using an x-ray slit imaging system. An observed spectral line broadening was 0.869 eV corresponding to a resolving power of 3600, including Doppler broadening of the x-ray source. Taking account of the measured source width, we made simulations using the SHADOW 3 code and got a nominal resolving power of 6500 for the spectrometer. This high nominal resolving power is due to a longer distance from the crystal to the detector, comparing with that in the early FCS.

  10. Ultra high vacuum adhesion testing of NERVA engine materials

    Science.gov (United States)

    1970-01-01

    The primary objective of this research program was to determine the effects of surface cleaning and deliberate gaseous contamination on the adhesion behavior of selected candidate materials for use in the NERVA nuclear rocket engine program. Using a torsion balance technique, the relationship between the normal compressive load applied to crossed rod samples and the resultant contact resistance was used to ascertain the extent of adhesion under each set of experimental conditions. In addition to an evaluation of the static adhesion behavior of selected materials combinations, the experimental apparatus was modified to permit a similar investigation relating to the effects of specific tangential displacements of the sample wires, i.e., their sliding friction behavior. During the course of this subcontract, the materials combinations 440 C vs. 440 C. pyrographite vs ZTA graphite, Nbc (graphite) vs. Nbc (graphite), and Electrolize Inconel 718 vs. Au electroplated 302 S/S were evaluated.

  11. Quality of Meat ( from Male Fallow Deer ( Packaged and Stored under Vacuum and Modified Atmosphere Conditions

    Directory of Open Access Journals (Sweden)

    N. Piaskowska

    2016-12-01

    Full Text Available This study evaluated the effect of vacuum and modified atmosphere (40% CO2+60% N2, MA packaging on the chemical composition, physicochemical properties and sensory attributes of chill-stored meat from 10 fallow deer (Dama dama bucks at 17 to 18 months of age. The animals were hunter-harvested in the forests of north-eastern Poland. During carcass dressing (48 to 54 h post mortem, both musculus longissimus muscles were cut out. Each muscle was divided into seven sections which were allocated to three groups: 0, A, and B. Samples 0 were immediately subjected to laboratory analyses. Samples A were vacuum-packaged, and samples B were packaged in MA. Packaged samples were stored for 7, 14, and 21 days at 2°C. The results of the present study showed that the evaluated packaging systems had no significant effect on the quality of fallow deer meat during chilled storage. However, vacuum-packaged meat samples were characterised by greater drip loss. Vacuum and MA packaging contributed to preserving the desired physicochemical properties and sensory attributes of meat during 21 days of storage. Regardless of the packaging method used, undesirable changes in the colour, water-holding capacity and juiciness of meat, accompanied by tenderness improvement, were observed during chilled storage.

  12. Spectroscopic study of amino acids adsorption on pyrite surface: From vacuum to solution conditions.

    Science.gov (United States)

    Mateo-Marti, E.; Sanchez-Arenillas, M.

    2015-10-01

    We characterized the adsorption of cystine molecules among other amino acids on pyrite surface via X-ray photoelectron spectroscopy. A novel comparative analysis revealed remarkable differences with respect to molecular adsorption and surface chemistry induced by environmental conditions. Pyrite is a highly reactive surface and contains two crucial types of surface functional groups that drive molecular chemistry on the surface depending on the surrounding conditions. Therefore, the systems explored in this study hold interesting implications for supporting catalyzed prebiotic chemistry reactions.

  13. Electron beam gun with kinematic coupling for high power RF vacuum devices

    Energy Technology Data Exchange (ETDEWEB)

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  14. High-Flux, High-Temperature Thermal Vacuum Qualification Testing of a Solar Receiver Aperture Shield

    Science.gov (United States)

    Kerslake, Thomas W.; Mason, Lee S.; Strumpf, Hal J.

    1997-01-01

    As part of the International Space Station (ISS) Phase 1 program, NASA Lewis Research Center (LERC) and the Russian Space Agency (RSA) teamed together to design, build and flight test the world's first orbital Solar Dynamic Power System (SDPS) on the Russian space station Mir. The Solar Dynamic Flight Demonstration (SDFD) program was to operate a nominal 2 kWe SDPS on Mir for a period up to 1-year starting in late 1997. Unfortunately, the SDFD mission was demanifested from the ISS phase 1 shuttle program in early 1996. However, substantial flight hardware and prototypical flight hardware was built including a heat receiver and aperture shield. The aperture shield comprises the front face of the cylindrical cavity heat receiver and is located at the focal plane of the solar concentrator. It is constructed of a stainless steel plate with a 1-m outside diameter, a 0.24-m inside diameter and covered with high-temperature, refractory metal Multi-Foil Insulation (MFI). The aperture shield must minimize heat loss from the receiver cavity, provide a stiff, high strength structure to accommodate shuttle launch loads and protect receiver structures from highly concentrated solar fluxes during concentrator off-pointing events. To satisfy Mir operational safety protocols, the aperture shield was required to accommodate direct impingement of the intensely concentrated solar image for a 1-hour period. To verify thermal-structural durability under the anticipated high-flux, high-temperature loading, an aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar flux for a period of 1-hour. In the first test, a near equilibrium temperature of 1862 K was attained in the center of the shield hot spot. In the second test, with increased incident flux, a near

  15. Gauge fields and gauge symmetry at high temperature: Possibility of a vacuum expectation value of O ( g sup 2 T )

    Energy Technology Data Exchange (ETDEWEB)

    Sawayanagi, H. (Kushiro National College of Technology, Kushiro, 084 (Japan))

    1992-05-15

    SU(2) gauge theory without fermions is studied at high temperature. The possibility that the temporal component of the gauge field {ital A}{sub 4} acquires a vacuum expectation value is considered. It is shown that in order to avoid tachyonic poles in a new vacuum, the magnitude of the vacuum expectation value {l angle}{ital gA}{sub 4}{r angle} is of order {ital g}{sup 2}{ital T}. We also consider an effective potential under the assumption that the effect of magneto- static gluons converges. We show that it is difficult to generate a vacuum expectation value of that order.

  16. A compact high vacuum heating chamber for in-situ x-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Bertram, F.; Deiter, C.; Pflaum, K.; Seeck, O. H. [Hamburger Synchrotronstrahlungslabor am Deutschen Elektronen-Synchrotron, Notkestr. 85, 22607 Hamburg (Germany)

    2012-08-15

    A very compact multi purpose high vacuum heating chamber for x-ray scattering techniques was developed. The compact design allows the chamber to be installed on high precision diffractometers which usually cannot support heavy and/or large equipment. The chamber is covered by a Be dome allowing full access to the hemisphere above the sample which is required for in-plane grazing incident x-ray diffraction and out-off plane wide angle x-ray diffraction.

  17. Preparation of High-Grade Powders from Tomato Paste Using a Vacuum Foam Drying Method.

    Science.gov (United States)

    Sramek, Martin; Schweiggert, Ralf Martin; van Kampen, Andreas; Carle, Reinhold; Kohlus, Reinhard

    2015-08-01

    We present a rapid and gentle drying method for the production of high-grade tomato powders from double concentrated tomato paste, comparing results with powders obtained by foam mat air drying and freeze dried powders. The principle of this method consists of drying tomato paste in foamed state at low temperatures in vacuum. The formulations were dried at temperatures of 50, 60, and 70 °C and vacuum of 200 mbar. Foam stability was affected by low serum viscosity and the presence of solid particles in tomato paste. Consequently, serum viscosity was increased by maltodextrin addition, yielding optimum stability at tomato paste:maltodextrin ratio of 2.4:1 (w/w) in dry matter. Material foamability was improved by addition of 0.5% (w/w, fresh weight) egg white. Because of solid particles in tomato paste, foam air filling had to be limited to critical air volume fraction of Φ = 0.7. The paste was first pre-foamed to Φ = 0.2 and subsequently expanded in vacuo. After drying to a moisture content of 5.6% to 7.5% wet base (w.b.), the materials obtained were in glassy state. Qualities of the resulting powders were compared with those produced by freeze and air drying. Total color changes were the least after vacuum drying, whereas air drying resulted in noticeable color changes. Vacuum foam drying at 50 °C led to insignificant carotenoid losses, being equivalent to the time-consuming freeze drying method. In contrast, air drying caused lycopene and β-carotene losses of 18% to 33% and 14% to 19% respectively. Thus, vacuum foam drying enables production of high-grade tomato powders being qualitatively similar to powders obtained by freeze drying. © 2015 Institute of Food Technologists®

  18. Ion effects in the SLC electron damping ring under exceptionally poor vacuum conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, F.; Krejcik, P.; Minty, M.; Pritzkau, D.; Raubenheimer, T.; Ross, M.; Woodley, M.

    1997-10-01

    In 1996, due to a catastrophic kicker chamber failure in the SLC electron damping ring, the ring vacuum system was contaminated for several months. During this time, the vertical emittance of the beam extracted from the ring was increased by a large factor (4--20). The emittance slowly decreased as the vacuum pressure gradually improved. At the same time, an intermittent vertical instability was observed. Both the emittance blow-up and the instability behavior depended strongly on beam current, ring pressure, number of bunches in the ring (1 or 2), duty cycle, store time and betatron tunes. In this report, the authors describe the observations, and compare them with predictions from classical ion-trapping and ion-instability theories.

  19. Ultra-High Vacuum Compatible Optical Chopper System for Synchrotron X-ray Scanning Tunneling Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hao; Cummings, Marvin L.; Shirato, Nozomi; Stripe, Benjamin D.; Rosenmann, Daniel; Preissner, Curt A.; Freeland, John W.; Kersell, Heath R.; Hla, Saw Wai; Rose, Volker

    2015-01-01

    High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the required beam attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.

  20. Ultra-high vacuum compatible optical chopper system for synchrotron x-ray scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hao, E-mail: hc000211@ohio.edu [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701 (United States); Cummings, Marvin; Shirato, Nozomi; Stripe, Benjamin; Preissner, Curt; Freeland, John W. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Rosenmann, Daniel [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Kersell, Heath; Hla, Saw-Wai [Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701 (United States); Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Rose, Volker, E-mail: vrose@anl.gov [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

    2016-01-28

    High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the required beam attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.

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

    Energy Technology Data Exchange (ETDEWEB)

    Vasileiadis, N.; Tatsios, G.; Misdanitis, S.; Valougeorgis, D., E-mail: diva@mie.uth.gr

    2016-02-15

    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.

  2. Effect of high solenoidal magnetic fields on breakdown voltages of high vacuum 805 MHz cavities

    Energy Technology Data Exchange (ETDEWEB)

    Moretti, A.; Bross, A.; Geer, S.; Qian, Z.; /Fermilab; Norem, J.; /Argonne; Li, D.; Zisman, M.; /LBL, Berkeley; Torun, Y.; /IIT, Chicago; Rimmer, R.; /Jefferson Lab; Errede,; /Illinois U., Urbana

    2005-10-01

    There is an on going international collaboration studying the feasibility and cost of building a muon collider or neutrino factory [1,2]. An important aspect of this study is the full understanding of ionization cooling of muons by many orders of magnitude for the collider case. An important muon ionization cooling experiment, MICE [3], has been proposed to demonstrate and validate the technology that could be used for cooling. Ionization cooling is accomplished by passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF Cavities within a multi-Tesla solenoidal field. To determine the effect of very large solenoidal magnetic fields on the generation of dark current, x-rays and on the breakdown voltage gradients of vacuum RF cavities, a test facility has been established at Fermilab in Lab G. This facility consists of a 12 MW 805 MHz RF station and a large warm bore 5 T solenoidal superconducting magnet containing a pill box type cavity with thin removable window apertures. This system allows dark current and breakdown studies of different window configurations and materials. The results of this study will be presented. The study has shown that the peak achievable accelerating gradient is reduced by a factor greater than 2 when solenoidal field of greater than 2 T are applied to the cavity.

  3. Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

    Directory of Open Access Journals (Sweden)

    Urs Gysin

    2015-12-01

    Full Text Available Background: The resolution in electrostatic force microscopy (EFM, a descendant of atomic force microscopy (AFM, has reached nanometre dimensions, necessary to investigate integrated circuits in modern electronic devices. However, the characterization of conducting or semiconducting power devices with EFM methods requires an accurate and reliable technique from the nanometre up to the micrometre scale. For high force sensitivity it is indispensable to operate the microscope under high to ultra-high vacuum (UHV conditions to suppress viscous damping of the sensor. Furthermore, UHV environment allows for the analysis of clean surfaces under controlled environmental conditions. Because of these requirements we built a large area scanning probe microscope operating under UHV conditions at room temperature allowing to perform various electrical measurements, such as Kelvin probe force microscopy, scanning capacitance force microscopy, scanning spreading resistance microscopy, and also electrostatic force microscopy at higher harmonics. The instrument incorporates beside a standard beam deflection detection system a closed loop scanner with a scan range of 100 μm in lateral and 25 μm in vertical direction as well as an additional fibre optics. This enables the illumination of the tip–sample interface for optically excited measurements such as local surface photo voltage detection.Results: We present Kelvin probe force microscopy (KPFM measurements before and after sputtering of a copper alloy with chromium grains used as electrical contact surface in ultra-high power switches. In addition, we discuss KPFM measurements on cross sections of cleaved silicon carbide structures: a calibration layer sample and a power rectifier. To demonstrate the benefit of surface photo voltage measurements, we analysed the contact potential difference of a silicon carbide p/n-junction under illumination.

  4. Generation of high charge state platinum ions on vacuum arc plasma heated by gyrotron radiation.

    Science.gov (United States)

    Yushkov, G Yu; Vodopyanov, A V; Nikolaev, A G; Izotov, I V; Savkin, K P; Golubev, S V; Oks, E M

    2014-02-01

    The hybrid high charge metal ion source based on vacuum arc plasma heated by gyrotron radiation into simple magnetic trap has been developed. Two types of magnetic traps were used: a mirror configuration and a cusp one with inherent "minimum-B" structure. Pulsed high power (>100 kW) gyrotrons with frequency 37.5 GHz and 75 GHz were used for heating the vacuum arc plasma injected into the traps. Two different ways were used for injecting the metal plasma-axial injection by a miniature arc source located on-axis near the microwave window, and simultaneous radial injection by a number of sources mounted radially at the midplane of the traps. This article represents all data gathered for platinum ions, thus making comparison of the experimental results obtained with different traps and injections convenient and accurate.

  5. Characterization of Magnetic Ni Clusters on Graphene Scaffold after High Vacuum Annealing

    CERN Document Server

    Zhang, Zhenjun; Grisafe, Benjamin; Lee, Ji Ung; Lloyd, James R

    2015-01-01

    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 x10-7 torr) annealing between 300 and 600 0C. 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 was 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 0C. Importantly, the resulting annealed clusters are relatively stable and no further oxidation was detectable after three weeks of air exposure at room temperature.

  6. Thermocouples of tantalum and rhenium alloys for more stable vacuum-high temperature performance

    Science.gov (United States)

    Morris, J. F. (Inventor)

    1977-01-01

    Thermocouples of the present invention provide stability and performance reliability in systems involving high temperatures and vacuums by employing a bimetallic thermocouple sensor wherein each metal of the sensor is selected from a group of metals comprising tantalum and rhenium and alloys containing only those two metals. The tantalum, rhenium thermocouple sensor alloys provide bare metal thermocouple sensors having advantageous vapor pressure compatibilities and performance characteristics. The compatibility and physical characteristics of the thermocouple sensor alloys of the present invention result in improved emf, temperature properties and thermocouple hot junction performance. The thermocouples formed of the tantalum, rhenium alloys exhibit reliability and performance stability in systems involving high temperatures and vacuums and are adaptable to space propulsion and power systems and nuclear environments.

  7. 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.

  8. Project W-320 high vacuum 241-AY-102 annulus ventilation system operability test report

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, J.W.

    1998-03-12

    This report documents the test results of OTP-320-001, Tank 241-AY-102 Annulus Ventilation System Testing. Included in the appendices are: (1) Supporting documentation prepared to demonstrate the structural integrity of the tank at high annulus vacuum (<20 INWG), and (2) a report that identifies potential cross connections between the primary and annulus ventilation systems. These cross connections were verified to be eliminated prior to the start of testing.

  9. Volatile Compounds Profile of Sous-Vide Cooked Pork Cheeks as Affected by Cooking Conditions (Vacuum Packaging, Temperature and Time

    Directory of Open Access Journals (Sweden)

    Jose Sanchez del Pulgar

    2013-10-01

    Full Text Available The volatile organic compound (VOC profile of pork cheeks as affected by the cooking conditions was investigated. Pork cheeks were cooked under different combinations of temperature (60 °C or 80 °C, time (5 or 12 h and vacuum (vacuum or air-packaged. As a general rule, the VOCs originating from lipid degradation were positively affected by the cooking temperature and negatively by the cooking time, reaching the highest amounts in pork cheeks cooked at 80 °C during 5 h and the lowest in samples cooked at 80 °C during 12 h. On the contrary, VOCs originated from amino acids and Maillard reactions were positively affected by both factors. The proportion between lipid degradation and amino acids reactions was estimated by the hexanal/3-methylbutanal ratio, which reached its highest values in samples cooked at 60 °C during 5 h in the presence of air and the lowest values in samples cooked at 80 °C during 12 h, regardless of the vacuum status.

  10. Simulations and Vacuum Tests of a CLIC Accelerating Structure

    CERN Document Server

    Garion, C

    2011-01-01

    The Compact LInear Collider, under study, is based on room temperature high gradient structures. The vacuum specificities of these cavities are low conductance, large surface areas and a non-baked system. The main issue is to reach UHV conditions (typically 10-7 Pa) in a system where the residual vacuum is driven by water outgassing. A finite element model based on an analogy thermal/vacuum has been built to estimate the vacuum profile in an accelerating structure. Vacuum tests are carried out in a dedicated set-up, the vacuum performances of different configurations are presented and compared with the predictions.

  11. Monte Carlo simulations of ultra high vacuum and synchrotron radiation for particle accelerators

    CERN Document Server

    AUTHOR|(CDS)2082330; Leonid, Rivkin

    With preparation of Hi-Lumi LHC fully underway, and the FCC machines under study, accelerators will reach unprecedented energies and along with it very large amount of synchrotron radiation (SR). This will desorb photoelectrons and molecules from accelerator walls, which contribute to electron cloud buildup and increase the residual pressure - both effects reducing the beam lifetime. In current accelerators these two effects are among the principal limiting factors, therefore precise calculation of synchrotron radiation and pressure properties are very important, desirably in the early design phase. This PhD project shows the modernization and a major upgrade of two codes, Molflow and Synrad, originally written by R. Kersevan in the 1990s, which are based on the test-particle Monte Carlo method and allow ultra-high vacuum and synchrotron radiation calculations. The new versions contain new physics, and are built as an all-in-one package - available to the public. Existing vacuum calculation methods are overvi...

  12. Vacuum Simulations in High Energy Accelerators and Distribution Properties of Continuous and Discrete Particle Motions

    CERN Document Server

    Aichinger, Ida; Kersevan, Roberto

    The underlying thesis on mathematical simulation methods in application and theory is structured into three parts. The first part sets up a mathematical model capable of predicting the performance and operation of an accelerator’s vacuum system based on analytical methods. A coupled species-balance equation system describes the distribution of the gas dynamics in an ultra-high vacuum system considering impacts of conductance limitations, beam induced effects (ion-, electron-, and photon-induced de- sorption), thermal outgassing and sticking probabilities of the chamber materials. A new solving algorithm based on sparse matrix representations, is introduced and presents a closed form solution of the equation system. The model is implemented in a Python environment, named PyVasco, and is supported by a graphical user interface to make it easy available for everyone. A sensitivity analysis, a cross-check with the Test-Particle Monte Carlo simulation program Molflow+ and a comparison of the simulation results t...

  13. High-energy vacuum birefringence and dichroism in an ultrastrong laser field

    Science.gov (United States)

    Meuren, Sebastian; Bragin, Sergey; Keitel, Christoph H.; di Piazza, Antonino

    2017-10-01

    The interaction between real photons in vacuum is a long-standing prediction of quantum electrodynamics, which has never been observed experimentally. Upcoming 10 PW laser systems like the Extreme Light Infrastructure (ELI) will provide laser pulses with unprecedented intensities. If combined with highly energetic gamma photons - obtainable via Compton backscattering from laser-wakefield accelerated electron beams - the QED critical field becomes accessible. In we have derived how a generally polarized probe photon beam is influenced by both vacuum birefringence and dichroism in a strong linearly polarized plane-wave laser field. We put forward an experimental scheme to measure these effects in the nontrivial high-energy regime, where the QED critical field is reached and the Euler-Heisenberg approximation, valid for low-frequency electromagnetic fields, breaks down. Our results suggest the feasibility of verifying/rejecting the QED prediction for vacuum birefringence/dichroism at the 3 σ confidence level on the time scale of a few days at several upcoming laser facilities. Now at Princeton University, Princeton, NJ.

  14. Densification control and analysis of outer shell of new high-temperature vacuum insulated composite

    Science.gov (United States)

    Wang, Yang; Chen, Zhaofeng; Jiang, Yun; Yu, Shengjie; Xu, Tengzhou; Li, Binbin; Chen, Zhou

    2017-11-01

    A novel high temperature vacuum insulated composite with low thermal conductivity composed of SiC foam core material and sealing outer shell is discussed, which will have a great potential to be used as thermal protection system material. In this composite, the outer shell is the key to maintain its internal vacuum, which is consisted of 2.5D C/C and SiC coating. So the densification processes of outer shell, including 2.5D braiding process, chemical vapor infiltration (CVI) pyrolytic carbon (PyC) process, polymer infiltration and pyrolysis (PIP) glassy carbon (GC) process and chemical vapor deposition (CVD) SiC process, are focused in this paper. The measuring result of the gas transmission quantity of outer shell is only 0.14 cm3/m2 · d · Pa after 5 times CVD processes, which is two order of magnitude lower than that sample deposited one time. After 10 times thermal shock cycles, the gas transmission quantity increases to 1.2 cm3/m2 · d · Pa. The effective thermal conductivity of high temperature vacuum insulated composite ranged from 0.19 W m‑1 K‑1 to 0.747 W m‑1 K‑1 within the temperature from 20 °C to 900 °C. Even after 10 thermal shock cycles, the variation of the effective thermal conductivity is still consistent with that without treatments.

  15. Windowless transition between atmospheric pressure and high vacuum via differential pumping for synchrotron radiation applications.

    Energy Technology Data Exchange (ETDEWEB)

    Gog, T.; Casa, D. M.; Kuzmenko, I.; Krakora, R. J.; Bolin, T. B.; X-Ray Science Division

    2007-07-01

    A differential pump assembly is introduced which can provide a windowless transition between the full atmospheric pressure of an in-air sample environment and the high-vacuum region of a synchrotron radiation beamline, while providing a clear aperture of approximately 1 mm to pass through the X-ray beam from a modern third-generation synchrotron radiation source. This novel pump assembly is meant to be used as a substitute for an exit vacuum window on synchrotron beamlines, where the existence of such a window would negatively impact the coherent nature of the X-ray beam or would introduce parasitic scattering, distorting weak scattering signals from samples under study. It is found that the length of beam pipe necessary to reduce atmospheric pressure to below 10 mbar is only about 130 mm, making the expected photon transmission for hard X-rays through this pipe competitive with that of a regular Be beamline window. This result is due to turbulent flow dominating the first pumping stage, providing a mechanism of strong gas conductance limitation, which is further enhanced by introducing artificial surface roughness in the pipe. Successive reduction of pressure through the transitional flow regime into the high-vacuum region is accomplished over a length of several meters, using beam pipes of increasing diameter. While the pump assembly has not been tested with X-rays, possible applications are discussed in the context of coherent and small-angle scattering.

  16. Proteometabolomic response of Deinococcus radiodurans exposed to UVC and vacuum conditions: Initial studies prior to the Tanpopo space mission.

    Science.gov (United States)

    Ott, Emanuel; Kawaguchi, Yuko; Kölbl, Denise; Chaturvedi, Palak; Nakagawa, Kazumichi; Yamagishi, Akihiko; Weckwerth, Wolfram; Milojevic, Tetyana

    2017-01-01

    The multiple extremes resistant bacterium Deinococcus radiodurans is able to withstand harsh conditions of simulated outer space environment. The Tanpopo orbital mission performs a long-term space exposure of D. radiodurans aiming to investigate the possibility of interplanetary transfer of life. The revealing of molecular machinery responsible for survivability of D. radiodurans in the outer space environment can improve our understanding of underlying stress response mechanisms. In this paper, we have evaluated the molecular response of D. radiodurans after the exposure to space-related conditions of UVC irradiation and vacuum. Notably, scanning electron microscopy investigations showed that neither morphology nor cellular integrity of irradiated cells was affected, while integrated proteomic and metabolomic analysis revealed numerous molecular alterations in metabolic and stress response pathways. Several molecular key mechanisms of D. radiodurans, including the tricarboxylic acid cycle, the DNA damage response systems, ROS scavenging systems and transcriptional regulators responded in order to cope with the stressful situation caused by UVC irradiation under vacuum conditions. These results reveal the effectiveness of the integrative proteometabolomic approach as a tool in molecular analysis of microbial stress response caused by space-related factors.

  17. Proteometabolomic response of Deinococcus radiodurans exposed to UVC and vacuum conditions: Initial studies prior to the Tanpopo space mission.

    Directory of Open Access Journals (Sweden)

    Emanuel Ott

    Full Text Available The multiple extremes resistant bacterium Deinococcus radiodurans is able to withstand harsh conditions of simulated outer space environment. The Tanpopo orbital mission performs a long-term space exposure of D. radiodurans aiming to investigate the possibility of interplanetary transfer of life. The revealing of molecular machinery responsible for survivability of D. radiodurans in the outer space environment can improve our understanding of underlying stress response mechanisms. In this paper, we have evaluated the molecular response of D. radiodurans after the exposure to space-related conditions of UVC irradiation and vacuum. Notably, scanning electron microscopy investigations showed that neither morphology nor cellular integrity of irradiated cells was affected, while integrated proteomic and metabolomic analysis revealed numerous molecular alterations in metabolic and stress response pathways. Several molecular key mechanisms of D. radiodurans, including the tricarboxylic acid cycle, the DNA damage response systems, ROS scavenging systems and transcriptional regulators responded in order to cope with the stressful situation caused by UVC irradiation under vacuum conditions. These results reveal the effectiveness of the integrative proteometabolomic approach as a tool in molecular analysis of microbial stress response caused by space-related factors.

  18. In situ preparation of biomimetic thin films and their surface-shielding effect for organisms in high vacuum.

    Directory of Open Access Journals (Sweden)

    Hiroshi Suzuki

    Full Text Available Self-standing biocompatible films have yet to be prepared by physical or chemical vapor deposition assisted by plasma polymerization because gaseous monomers have thus far been used to create only polymer membranes. Using a nongaseous monomer, we previously found a simple fabrication method for a free-standing thin film prepared from solution by plasma polymerization, and a nano-suit made by polyoxyethylene (20 sorbitan monolaurate can render multicellular organisms highly tolerant to high vacuum. Here we report thin films prepared by plasma polymerization from various monomer solutions. The films had a flat surface at the irradiated site and were similar to films produced by vapor deposition of gaseous monomers. However, they also exhibited unique characteristics, such as a pinhole-free surface, transparency, solvent stability, flexibility, and a unique out-of-plane molecular density gradient from the irradiated to the unirradiated surface of the film. Additionally, covering mosquito larvae with the films protected the shape of the organism and kept them alive under the high vacuum conditions in a field emission-scanning electron microscope. Our method will be useful for numerous applications, particularly in the biological sciences.

  19. Development of Sub-Ischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

    Science.gov (United States)

    2011-10-01

    hyperplasia are all skin conditions that are attributed to external pressures applied to the residual limb (Lyon et al., 2000). 1.1.3 VACUUM ASSISTED...C. C., Kulkarni, J., Zimerson, E., Ross, E. V., Beck, M. H. Skin Disorders in Amputees. Journal of the American Academy of Dermatology , 2000. 42(3...was filled with green colored water and vacuum turned on to see if the subatmospheric pressure would pull the fluid through the liner (Figure 7

  20. Lactobacillus role during conditioning of refrigerated and vacuum-packaged Argentinean meat.

    Science.gov (United States)

    Fadda, S; Chambon, C; Champomier-Vergès, M C; Talon, R; Vignolo, G

    2008-07-01

    The role of Lactobacillus strains with bioprotective and technological potential on raw beef during 15days of storage under vacuum at 7°C was investigated. The assayed strains were able to grow on the meat, Lactobacillus curvatus CRL705 and Lactobacillus sakei 23K showing the highest competitiveness. A net increase of amino acids was determined in inoculated samples when compared to the control, this being maximal for Lactobacillus plantarum CRL681. Although an important endogenous activity of meat sarcoplasmic proteins was observed, the disappearance of protein bands and the generation of a new one were detected as a consequence of Lactobacillus growth. A synergistic effect of Lactobacillus in combination with the muscle proteolytic enzyme complex can be suggested. From the studied strains, the bacteriocin producer L. curvatus CRL705 may be considered as a good candidate to contribute to meat ageing by means of small peptides and free amino acids generation while improving shelf life.

  1. Characterization of a Pressure-Fed LOX/LCH4 Reaction Control System Under Simulated Altitude and Thermal Vacuum Conditions

    Science.gov (United States)

    Atwell, Matthew J.; Melcher, John C.; Hurlbert, Eric A.; Morehead, Robert L.

    2017-01-01

    A liquid oxygen, liquid methane (LOX/LCH4) reaction control system (RCS) was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under simulated altitude and thermal vacuum conditions. The RCS is a subsystem of the Integrated Cryogenic Propulsion Test Article (ICPTA) and was initially developed under Project Morpheus. Composed of two 28 lbf-thrust and two 7 lbf-thrust engines, the RCS is fed in parallel with the ICPTA main engine from four propellant tanks. 40 tests consisting of 1,010 individual thruster pulses were performed across 6 different test days. Major test objectives were focused on system dynamics, and included characterization of fluid transients, manifold priming, manifold thermal conditioning, thermodynamic vent system (TVS) performance, and main engine/RCS interaction. Peak surge pressures from valve opening and closing events were examined. It was determined that these events were impacted significantly by vapor cavity formation and collapse. In most cases the valve opening transient was more severe than the valve closing. Under thermal vacuum conditions it was shown that TVS operation is unnecessary to maintain liquid conditions at the thruster inlets. However, under higher heat leak environments the RCS can still be operated in a self-conditioning mode without overboard TVS venting, contingent upon the engines managing a range of potentially severe thermal transients. Lastly, during testing under cold thermal conditions the engines experienced significant ignition problems. Only after warming the thruster bodies with a gaseous nitrogen purge to an intermediate temperature was successful ignition demonstrated.

  2. First high-convergence cryogenic implosion in a near-vacuum hohlraum.

    Science.gov (United States)

    Berzak Hopkins, L F; Meezan, N B; Le Pape, S; Divol, L; Mackinnon, A J; Ho, D D; Hohenberger, M; Jones, O S; Kyrala, G; Milovich, J L; Pak, A; Ralph, J E; Ross, J S; Benedetti, L R; Biener, J; Bionta, R; Bond, E; Bradley, D; Caggiano, J; Callahan, D; Cerjan, C; Church, J; Clark, D; Döppner, T; Dylla-Spears, R; Eckart, M; Edgell, D; Field, J; Fittinghoff, D N; Gatu Johnson, M; Grim, G; Guler, N; Haan, S; Hamza, A; Hartouni, E P; Hatarik, R; Herrmann, H W; Hinkel, D; Hoover, D; Huang, H; Izumi, N; Khan, S; Kozioziemski, B; Kroll, J; Ma, T; MacPhee, A; McNaney, J; Merrill, F; Moody, J; Nikroo, A; Patel, P; Robey, H F; Rygg, J R; Sater, J; Sayre, D; Schneider, M; Sepke, S; Stadermann, M; Stoeffl, W; Thomas, C; Town, R P J; Volegov, P L; Wild, C; Wilde, C; Woerner, E; Yeamans, C; Yoxall, B; Kilkenny, J; Landen, O L; Hsing, W; Edwards, M J

    2015-05-01

    Recent experiments on the National Ignition Facility [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] demonstrate that utilizing a near-vacuum hohlraum (low pressure gas-filled) is a viable option for high convergence cryogenic deuterium-tritium (DT) layered capsule implosions. This is made possible by using a dense ablator (high-density carbon), which shortens the drive duration needed to achieve high convergence: a measured 40% higher hohlraum efficiency than typical gas-filled hohlraums, which requires less laser energy going into the hohlraum, and an observed better symmetry control than anticipated by standard hydrodynamics simulations. The first series of near-vacuum hohlraum experiments culminated in a 6.8 ns, 1.2 MJ laser pulse driving a 2-shock, high adiabat (α∼3.5) cryogenic DT layered high density carbon capsule. This resulted in one of the best performances so far on the NIF relative to laser energy, with a measured primary neutron yield of 1.8×10(15) neutrons, with 20% calculated alpha heating at convergence ∼27×.

  3. Thermal Performance of Aged and Weathered Spray-On Foam Insulation (SOFI) Materials Under Cryogenic Vacuum Conditions (Cryostat-4)

    Science.gov (United States)

    2008-01-01

    The NASA Cryogenics Test Laboratory at Kennedy Space Center conducted long-term testing of SOFI materials under actual-use cryogenic conditions with Cryostat-4. The materials included in the testing were NCFI 24-124 (acreage foam), BX-265 (close-out foam, including intertank flange and bipod areas), and a potential alternate material, NCFI 27-68, (acreage foam with the flame retardant removed). Specimens of these materials were placed at two locations: a site that simulated aging (the Vehicle Assembly Building [VAB]) and a site that simulated weathering (the Atmospheric Exposure Test Site [beach site]). After aging/weathering intervals of 3, 6, and 12 months, the samples were retrieved and tested for their thermal performance under cryogenic vacuum conditions with test apparatus Cryostat-4.

  4. Case report of nipple shield trauma associated with breastfeeding an infant with high intra-oral vacuum.

    Science.gov (United States)

    Perrella, Sharon L; Lai, Ching T; Geddes, Donna T

    2015-07-26

    Nipple pain is associated with early cessation of breastfeeding and may be caused by high intra-oral vacuum. However identification of high intra-oral vacuum is typically restricted to the research setting. This is the first reported case of an infant with high intra-oral vacuum that was clinically identified through a specific pattern of nipple trauma associated with nipple shield use. Knowledge of clinical signs associated with high intra-oral vacuum may facilitate early recognition of this unusual breastfeeding challenge. The mother of an exclusively breastfed 3 month old infant had severe bilateral nipple pain with minimal trauma that persisted from birth. The nipples were not misshapen immediately after breastfeeding and adjustments to infant attachment at the breast did not attenuate the pain. Examination of the infant's oral anatomy was unremarkable with no ankyloglossia present. Microbiological cultures of nipple swabs and breast milk were negative for bacterial and fungal growth, and prescribed antimicrobial treatments did not reduce the nipple pain. Mild blanching and erythema of the nipples were occasionally observed, and were not consistent with nipple vasospasm. Nipple shields were used regularly as they modified the pain, although this resulted in blisters that corresponded with the nipple shield holes. Measurement of infant intra-oral vacuum during breastfeeding confirmed intra-oral vacuum up to 307 % higher than reference values. Breastfeeding gradually became less painful, and after 6 months was completely comfortable. High intra-oral vacuum is difficult to assess in the clinical setting and is likely an under-reported cause of early weaning that is not well understood. This original case report highlights high intra-oral vacuum as at differential diagnosis to be considered by health professionals when evaluating mothers experiencing strong nipple pain during the initiation of breastfeeding. A clinical screening tool is needed to enable prompt

  5. Use of high-thermal conductive aluminum nitride based ceramics in vacuum UHF electronic devices

    Directory of Open Access Journals (Sweden)

    Chasnyk V. I.

    2013-06-01

    Full Text Available Analysis of properties and characteristics of the alumina, beryllium oxide and aluminum nitride based ceramic materials used in UHF electronic devices has been made. It was shown that the complex of parameters including structural and functional characteristics of the high-thermal conductive aluminum nitride ceramics prevail over all types of alumina ceramics and is not lower than the same characteristics of the beryllium oxide ceramics especially at the temperatures higher than 450 °C. The examples of the prevailing use of the aluminum nitride ceramics inside vacuum UHF-region devices: TWT’s and klystrons.

  6. Head for high speed spinner having a vacuum chuck. [holding silicon dioxide chips for etching

    Science.gov (United States)

    Lombardi, F. (Inventor)

    1981-01-01

    The head for a high-speed spinner is characterized by a substantially cylindrical body adapted to be mounted at the distal end of a vertically oriented drive shaft. A vacuum chuck with an upwardly facing chamber is circumscribed by an annular surface for receiving in supported relation a silicon chip. An ordered array of low-pressure cavities is defined about the periphery of the body and connected in communication with the chamber via radially extended bores in order to translate low pressures to the chamber as the head is angularly displaced. A pressure differential is thereby established across the chip for securing it to the head.

  7. High Contrast Vacuum Nuller Testbed (VNT) Contrast, Performance and Null Control

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.

    2012-01-01

    Herein we report on our Visible Nulling Coronagraph high-contrast result of 109 contrast averaged over a focal planeregion extending from 14 D with the Vacuum Nuller Testbed (VNT) in a vibration isolated vacuum chamber. TheVNC is a hybrid interferometriccoronagraphic approach for exoplanet science. It operates with high Lyot stopefficiency for filled, segmented and sparse or diluted-aperture telescopes, thereby spanning the range of potential futureNASA flight telescopes. NASAGoddard Space Flight Center (GSFC) has a well-established effort to develop the VNCand its technologies, and has developed an incremental sequence of VNC testbeds to advance this approach and itsenabling technologies. These testbeds have enabled advancement of high-contrast, visible light, nulling interferometry tounprecedented levels. The VNC is based on a modified Mach-Zehnder nulling interferometer, with a W configurationto accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters.We give an overview of the VNT and discuss the high-contrast laboratory results, the optical configuration, criticaltechnologies and null sensing and control.

  8. Preparation methodology and possible treatments for improved ceramics for high voltage vacuum applications

    CERN Document Server

    Tan, J

    1998-01-01

    The flashover characteristics of an insulator bridged high voltage vacuum gap can play an important role in the overall performance of a high voltage device, for example in the extreme environments of high energy particle accelerators. The detailed preparation of the insulators is, at present, governed by the commercial production methods and by standard bulk cleaning processes, which for a particular application may be far from optimum. The influence of the mechanical preparation, thermal history and particular cleaning technique have been investigated for commercially available alumina samples, with measurement of surface characteristics by scanning electron microscopy and laser diffraction, measurement of the secondary electron emission curve and analysis of the high voltage performance with the possibility of applied fields up to 200kV/cm. The results of the different measurements are discussed in the overall context of the problems encountered in the full sized high voltage devices, and suggestions are m...

  9. Development of High Temperature Type Vacuum Insulation Panel using Soluble Polyimide and Characteristic Evaluation

    Science.gov (United States)

    Araki, Kuninari; Kamoto, Daigorou; Matsuoka, Shin-Ichi

    The utilization is expected from the high-insulated characteristic as a tool for energy saving also in the high temperature insulation fields as in vacuum insulation panels (VIP) in the future. For high temperature, the material composition and process of VIP were reviewed, the SUS foil was adopted as packaging material, and soluble polyimide was developed as the thermo compression bonding material for high temperature VIP at 150°C. To lower the glass-transition temperature (Tg) under 200°C, we elaborated the new soluble polyimide using aliphatic diamine copolymer, and controlled Tg to about 176°C. By making from trial VIP and evaluations, it was possible to be maintain high performance concerning the coefficient of thermal conductivity [λ<0.008 W/(m·K) at 150°C].

  10. arXiv Analytical methods for vacuum simulations in high energy accelerators for future machines based on LHC performances

    CERN Document Server

    Aichinger, Ida; Chiggiato, Paolo

    The Future Circular Collider (FCC), currently in the design phase, will address many outstanding questions in particle physics. The technology to succeed in this 100 km circumference collider goes beyond present limits. Ultra-high vacuum conditions in the beam pipe is one essential requirement to provide a smooth operation. Different physics phenomena as photon-, ion- and electron- induced desorption and thermal outgassing of the chamber walls challenge this requirement. This paper presents an analytical model and a computer code PyVASCO that supports the design of a stable vacuum system by providing an overview of all the gas dynamics happening inside the beam pipes. A mass balance equation system describes the density distribution of the four dominating gas species $\\text{H}_2, \\text{CH}_4$, $\\text{CO}$ and $\\text{CO}_2$. An appropriate solving algorithm is discussed in detail and a validation of the model including a comparison of the output to the readings of LHC gauges is presented. This enables the eval...

  11. INFLUENCE OF THE HIGHER ORDER DERIVATIVES ON THE PLANET PERIHELION PRECESSION IN THE EINSTEIN FIELD EQUATIONS FOR VACUUM CONDITION

    Directory of Open Access Journals (Sweden)

    Teguh Budi Prayitno

    2011-04-01

    Full Text Available This paper studies the effect of higher order derivative tensor in the Einstein field equations for vacuum condition on the planet perihelion precession. This tensor was initially proposed as the space-time curvature tensor by Deser and Tekin on discussions about the energy effects caused by this tensor. However, they include this tensor to Einstein field equations as a new model in general relativity theory. This is very interesting since there are some questions in cosmology and astrophysics that have no answers. Thus, they hoped this model could solve those problems by finding analytical or perturbative solution and interpreting it. In this case, the perturbative solution was used to find the Schwarzschild solution and it was also applied to consider the planetary motion in the solar gravitational field. Furthermore, it was proven that the tensor is divergence-free in order to keep the Einstein field equations remain valid.

  12. High Temperature Vacuum Annealing and Hydrogenation Modification of Exfoliated Graphite Nanoplatelets

    Directory of Open Access Journals (Sweden)

    Xiaobing Li

    2013-01-01

    Full Text Available Highly active defect sites on the edges of graphene automatically capture oxygen from air to form various oxygen groups. A two-step procedure to remove various oxygen functional groups from the defect sites of exfoliated graphene nanoplatelets (GNPs has been developed to reduce the atomic oxygen concentration from 9.5% to 4.8%. This two-step approach involves high temperature vacuum annealing followed by hydrogenation to protect the reduced edge carbon atoms from recombining with the atmospheric oxygen. The reduced GNPs exhibit decreased surface resistance and graphitic potential-dependent capacitance characteristics compared to the complex potential-dependent capacitance characteristics exhibited by the unreduced GNPs as a result of the removal of the oxygen functional groups present primarily at the edges. These reduced GNPs also exhibit high electrochemical cyclic stability for electrochemical energy storage applications.

  13. [Design and study of a high resolution vacuum ultraviolet imaging spectrometer carried by satellite].

    Science.gov (United States)

    Yu, Lei; Lin, Guan-yu; Qu, Yi; Wang, Shu-rong; Wang, Long-qi

    2011-12-01

    A high resolution vacuum ultraviolet imaging spectrometer prototype carried by satellite applied to the atmosphere detection of particles distribution in 115-300 nm was developed for remote sensing. First, based on the analysis of advanced loads, the optical system including an off-axis parabolic mirror as the telescope and Czerny-Turner structure as the imaging spectrometer was chosen Secondly, the 2-D photon counting detector with MCP was adopted for the characteristic that the radiation is weak in vacuum ultraviolet waveband. Then the geometric method and 1st order differential calculation were introduced to improve the disadvantages that aberrations in the traditional structure can not be corrected homogeneously to achieve perfect broadband imaging based on the aberration theory. At last, an advanced example was designed. The simulation and calculation of results demonstrate that the modulation transfer function (MTF) of total field of view is more than 0.6 in the broadband, and the spectral resolution is 1.23 nm. The structure is convenient and predominant. It proves that the design is feasible.

  14. Towards high-capacity fibre-optic communications at the speed of light in vacuum

    Science.gov (United States)

    Poletti, F.; Wheeler, N. V.; Petrovich, M. N.; Baddela, N.; Numkam Fokoua, E.; Hayes, J. R.; Gray, D. R.; Li, Z.; Slavík, R.; Richardson, D. J.

    2013-04-01

    Wide-bandwidth signal transmission with low latency is emerging as a key requirement in a number of applications, including the development of future exaflop-scale supercomputers, financial algorithmic trading and cloud computing. Optical fibres provide unsurpassed transmission bandwidth, but light propagates 31% slower in a silica glass fibre than in vacuum, thus compromising latency. Air guidance in hollow-core fibres can reduce fibre latency very significantly. However, state-of-the-art technology cannot achieve the combined values of loss, bandwidth and mode-coupling characteristics required for high-capacity data transmission. Here, we report a fundamentally improved hollow-core photonic-bandgap fibre that provides a record combination of low loss (3.5 dB km-1) and wide bandwidth (160 nm), and use it to transmit 37 × 40 Gbit s-1 channels at a 1.54 µs km-1 faster speed than in a conventional fibre. This represents the first experimental demonstration of fibre-based wavelength division multiplexed data transmission at close to (99.7%) the speed of light in vacuum.

  15. Simple, highly efficient vacuum-processed bulk heterojunction solar cells based on merocyanine dyes

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, Vera; Kronenberg, Nils M.; Lenze, Martin R.; Graf, Steven M.; Hertel, Dirk; Meerholz, Klaus [Department fuer Chemie, Universitaet Koeln, Luxemburger Strasse 116, 50939 Koeln (Germany); Buerckstuemmer, Hannah; Tulyakova, Elena V.; Wuerthner, Frank [Institut fuer Organische Chemie and Roentgen Research Center for Complex Material Systems, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany)

    2011-10-15

    In order to be competitive on the energy market, organic solar cells with higher efficiency are needed. To date, polymer solar cells have retained the lead with efficiencies of up to 8%. However, research on small molecule solar cells has been catching up throughout recent years and is showing similar efficiencies, however, only for more sophisticated multilayer device configurations. In this work, a simple, highly efficient, vacuum-processed small molecule solar cell based on merocyanine dyes - traditional colorants that can easily be mass-produced and purified - is presented. In the past, merocyanines have been successfully introduced in solution-processed as well as vacuum-processed devices, demonstrating efficiencies up to 4.9%. Here, further optimization of devices is achieved while keeping the same simple layer stack, ultimately leading to efficiencies beyond the 6% mark. In addition, physical properties such as the charge carrier transport and the cell performance under various light intensities are addressed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Highly transparent and conductive ZnO:Al thin films prepared by vacuum arc plasma evaporation

    Science.gov (United States)

    Miyata, Toshihiro; Minamino, Youhei; Ida, Satoshi; Minami, Tadatsugu

    2004-07-01

    A vacuum arc plasma evaporation (VAPE) method using both oxide fragments and gas sources as the source materials is demonstrated to be very effective for the preparation of multicomponent oxide thin films. Highly transparent and conductive Al-doped ZnO (AZO) thin films were prepared by the VAPE method using a ZnO fragment target and a gas source Al dopant, aluminum acethylacetonate (Al(C5H7O2)3) contained in a stainless steel vessel. The Al content in the AZO films was altered by controlling the partial pressure (or flow rate) of the Al dopant gas. High deposition rates as well as uniform distributions of resistivity and thickness on the substrate surface were obtained on large area glass substrates. A low resistivity on the order of 10-4 Ω cm and an average transmittance above 80% in the visible range were obtained in AZO thin films deposited on glass substrates. .

  17. Modelingof Acetylene Pyrolysis under Steel Vacuum Carburizing Conditions in a Tubular Flow Reactor

    OpenAIRE

    Rainer Reimert; Frank Graf; Siegfried Bajohr; Rafi Ullah Khan

    2007-01-01

    In the present work, the pyrolysis of acetylene was studied under steel vacuumcarburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from650 °C to 1050 °C. The partial pressure of acetylene in the feed mixture was 10 and 20mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressureof the mixture was 1.6 bar. A kinetic mechanism which consists of seven species andnine reactions has been used in the commercial computational fluid...

  18. Nano-materials for adhesive-free adsorbers for bakable extreme high vacuum cryopump surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stutzman, Marcy; Jordan, Kevin; Whitney, Roy R.

    2016-10-11

    A cryosorber panel having nanomaterials used for the cryosorption material, with nanomaterial either grown directly on the cryopanel or freestanding nanomaterials attached to the cryopanel mechanically without the use of adhesives. Such nanomaterial cryosorber materials can be used in place of conventional charcoals that are attached to cryosorber panels with special low outgassing, low temperature capable adhesives. Carbon nanotubes and other nanomaterials could serve the same purpose as conventional charcoal cryosorbers, providing a large surface area for cryosorption without the need for adhesive since the nanomaterials can be grown directly on a metallic substrate or mechanically attached. The nanomaterials would be capable of being fully baked by heating above 100.degree. C., thereby eliminating water vapor from the system, eliminating adhesives from the system, and allowing a full bake of the system to reduce hydrogen outgassing, with the goal of obtaining extreme high vacuum where the pump can produce pressures below 1.times.10.sup.-12 Torr.

  19. New perspectives in vacuum high voltage insulation. I. The transition to field emission

    CERN Document Server

    Diamond, W T

    1998-01-01

    Vacuum high-voltage insulation has been investigated for many years. Typically, electrical breakdown occurs between two broad-area electrodes at electric fields 100-1000 times lower than the breakdown field (about 5000 MV/m) between a well-prepared point cathode and a broad-area anode. Explanations of the large differences remain unsatisfactory, usually evoking field emission from small projections on the cathode that are subject to higher peak fields. The field emission then produces secondary effects that lead to breakdown. This article provides a significant resolution to this long standing problem. Field emission is not present at all fields, but typically starts after some process occurs at the cathode surface. Three effects have been identified that produce the transition to field emission: work function changes; mechanical changes produced by the strong electrical forces on the electrode surfaces; and gas desorption from the anode with sufficient density to support an avalanche discharge. Material adso...

  20. VAK, vacuum fluctuation and the mass spectrum of high energy particle physics

    CERN Document Server

    El-Naschie, M S

    2003-01-01

    We introduce a fundamental hypothesis identifying quantum vacuum fluctuation with the vague attractor of Kolmogorov, the so-called VAK. This Hamiltonian conterpart of a dissipative attractor is then modelled by epsilon sup ( supinfinity sup ) , topology as a 'limit set' of a wild dynamics generated by Moebius-like transformation of space. We proceed as follows: First we give an introduction to the epsilon sup ( supinfinity sup ) quantum spacetime theory from the point of view of nonlinear dynamics, complexity, string and KAM theory. Subsequently we give without proof several theorems and conjectures that we consider to be fundamental to the foundation of any general theory for high energy particles interaction. The final picture seems to be a synthesis between compactified Kleinian groups acting on an essentially nonlinear dynamics of a KAM system which enables us to give a very accurate estimation of the mass spectrum of the standard model and further still we are granted a glimpse into the physics of grand ...

  1. Vacuum electronics

    CERN Document Server

    Eichmeier, Joseph A

    2008-01-01

    Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. ""Vacuum Electronics"" covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

  2. Modelingof Acetylene Pyrolysis under Steel Vacuum Carburizing Conditions in a Tubular Flow Reactor

    Directory of Open Access Journals (Sweden)

    Rainer Reimert

    2007-03-01

    Full Text Available In the present work, the pyrolysis of acetylene was studied under steel vacuumcarburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from650 °C to 1050 °C. The partial pressure of acetylene in the feed mixture was 10 and 20mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressureof the mixture was 1.6 bar. A kinetic mechanism which consists of seven species andnine reactions has been used in the commercial computational fluid dynamics (CFDsoftware Fluent. The species transport and reaction model of Fluent was used in thesimulations. A comparison of simulated and experimental results is presented in thispaper.

  3. Internship Tasks Associated With CIF Icy Regolith Excavation and Volatile Capture Under Vacuum Conditions

    Science.gov (United States)

    Ballesteros, Erik Nicholas

    2014-01-01

    Understanding the surface and atmosphere of Mars is critical to current and future development of exploration systems. Dealing with the Martian regolith-the top layer of soil-remains a significant challenge, and much research is still needed. Addressing this need, the Cryogenics Test Lab and Granular Mechanics and Regolith Operations Lab at NASA's Kennedy Space Center are partnering to develop an apparatus that utilizes simulated Martian regolith in an analogous atmospheric environment to gather data about how the material behaves when exposed to water vapor. Martian surface temperatures range from 128 K (-145 C) to 308 K (35 C), and the average pressure is approximately 4.5 Torr; which presents an environment where water can potentially exist in vapor, solid or liquid form. And based on prior Mars missions such as the Phoenix Lander, it is known that water-ice exists just below the surface. This test apparatus will attempt to recreate the conditions that contributed to the Martian ice deposits by exposing a sample to water vapor at low pressure and temperature; thereby forming ice inside the simulant via diffusion. From this, we can better understand the properties and behavior of the regolith, and have more knowledge concerning its ability to store water-and subsequently, how to dig up and extract that water-which will be crucial to sample gathering when the first manned Mars mission takes place.

  4. Nanoscale Vacuum Channel Transistor.

    Science.gov (United States)

    Han, Jin-Woo; Moon, Dong-Il; Meyyappan, M

    2017-04-12

    Vacuum tubes that sparked the electronics era had given way to semiconductor transistors. Despite their faster operation and better immunity to noise and radiation compared to the transistors, the vacuum device technology became extinct due to the high power consumption, integration difficulties, and short lifetime of the vacuum tubes. We combine the best of vacuum tubes and modern silicon nanofabrication technology here. The surround gate nanoscale vacuum channel transistor consists of sharp source and drain electrodes separated by sub-50 nm vacuum channel with a source to gate distance of 10 nm. This transistor performs at a low voltage (3 microamperes). The nanoscale vacuum channel transistor can be a possible alternative to semiconductor transistors beyond Moore's law.

  5. Thermal properties of high temperature vacuum receivers used for parabolic trough solar thermal power system

    Directory of Open Access Journals (Sweden)

    Qinghe Yu

    2017-08-01

    Full Text Available The receiver's emittance and vacuum pressure are the two of great significance issues on the heat-loss which is the main factor reducing the efficiency of the parabolic though systems. In this paper, the thermal steady-state equilibrium method was used to test the receivers’ heat-loss. The receivers with increasing emittance were tested to study the variation of heat-loss. Meanwhile, the variable vacuum pressure in the annulus that affects the efficiency of the system was investigated. The influence of vacuumizing rate and getters on the vacuum pressure and heat-loss were discussed. The result shows that the emittance and vacuum pressure affect the receiver's heat-loss dramatically, and the emittance is the major influence factor on the thermal properties. The receiver with 0.08 emittance and 10−3 Pa vacuum pressure has a satisfactory heat-loss of 215.6 W/m at 400 °C. The analysis further reveals that the synergistic effect of both emittance and vacuum pressure on the heat-loss can be reflected by the packaging temperature of the glass tube, and a fitting formula has been established to estimate the receivers’ heat-loss according to the packaging temperature of the glass tube.

  6. Wound conditioning by vacuum assisted closure (V.A.C.) in postoperative infections after dorsal spine surgery

    Science.gov (United States)

    Keel, Marius; Trentz, Otmar; Heinzelmann, Michael

    2006-01-01

    The use of vacuum assisted closure (V.A.C.) therapy in postoperative infections after dorsal spinal surgery was studied retrospectively. Successful treatment was defined as a stable healed wound that showed no signs of acute or chronic infection. The treatment of the infected back wounds consisted of repeated debridement, irrigation and open wound treatment with temporary closure by V.A.C. The instrumentation was exchanged or removed if necessary. Fifteen patients with deep subfascial infections after posterior spinal surgery were treated. The implants were exchanged in seven cases, removed completely in five cases and left without changing in one case. In two cases spinal surgery consisted of laminectomy without instrumentation. In two cases only the wound defects were closed by muscle flap, the remaining ones were closed by delayed suturing. Antibiotic treatment was necessary in all cases. Follow up was possible in 14 patients. One patient showed a new infection after treatment. The study illustrates the usefulness of V.A.C. therapy as a new alternative management for wound conditioning of complex back wounds after deep subfascial infection. PMID:16835734

  7. Systematic study of the dolomite (104) surface by bimodal dynamic force microscopy in ultra-high vacuum.

    Science.gov (United States)

    Kawai, Shigeki; Pina, Carlos M; Bubendorf, Alexander; Fessler, Gregor; Glatzel, Thilo; Gnecco, Enrico; Meyer, Ernst

    2013-02-08

    We have investigated the morphology and structure of dolomite MgCa(CO(3))(2)(104) surfaces by bimodal dynamic force microscopy with flexural and torsional resonance modes in ultra-high vacuum at room temperature. We found that the surface slowly decomposes by degassing CO(2) in a vacuum and becomes covered by amorphous clusters, presumably MgO and CaO. By choosing an optimal sample preparation procedure (i.e. cleaving in a vacuum and mild annealing for stabilizing clusters for a short time), atomically clean surfaces were obtained. The complex tip-sample interaction, arising from carbonate groups and Mg and Ca atoms of the surface, induces a large variety of atomic-scale imaging features.

  8. Plasmon-assisted chemical reactions revealed by high-vacuum tip-enhanced Raman spectroscopy

    Science.gov (United States)

    Lu, Shuaicheng; Sheng, Shaoxiang; Zhang, Zhenglong; Xu, Hongxing; Zheng, Hairong

    2014-08-01

    Tip-enhanced Raman spectroscopy (TERS) is the technique that combines the nanoscale spatial resolution of a scanning probe microscope and the highly sensitive Raman spectroscopy enhanced by the surface plasmons. It is suitable for chemical analysis at nanometer scale. Recently, TERS exhibited powerful potential in analyzing the chemical reactions at nanoscale. The high sensitivity and spatial resolution of TERS enable us to learn the reaction processes more clearly. More importantly, the chemical reaction in TERS is assisted by surface plasmons, which provides us an optical method to manipulate the chemical reactions at nanoscale. Here using our home-built high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) setup, we successfully observed the plasmon-assisted molecule dimerization and dissociation reactions. In HV-TERS system, under laser illumination, 4-nitrobenzenethiol (4NBT) molecules can be dimerized to p,p'-dimercaptoazobenzene (DMAB), and dissociation reaction occurs for malachite green (MG) molecules. Using our HV-TERS setup, the dynamic processes of the reactions are clearly revealed. The chemical reactions can be manipulated by controlling the plasmon intensity through changing the power of the incident laser, the tunneling current and the bias voltage. We also investigated the role of plasmonic thermal effect in the reactions by measuring both the Stokes and anti- Stokes Raman peaks. Our findings extend the applications of TERS, which can help to study the chemical reactions and understand the dynamic processes at single molecular level, and even design molecules by the plasmon-assisted chemical reactions.

  9. Laterally self-oscillated and force-balanced microvibratory gyroscope packaged in a vacuum package with a conditioning ASIC

    Science.gov (United States)

    Park, Kyu-Yeon; Lee, Chong-Won; Oh, Yong-Soo; Lee, Byeungleul

    1997-11-01

    A novel concept self-oscillator and dynamically tunable micro vibratory gyroscope, where oscillating, position- sensing and force-balancing take place on the wafer surface, has been developed. The gyroscope consists of: a grid-type planar mass which oscillates on the wafer surface; pairs of the differential capacitor type with LT shape position sense electrodes; a pair of force-balancing electrodes; oppositely placed comb-drive and comb-sensor for mass self-oscillation; fish hook shape springs to match the first and second modes with the mass oscillating and position sensing modes, respectively. The natural frequency of the position sensing mode is lowered and tuned by the DC bias voltage applied to the position sense electrodes and then finely tuned by DC bias on a pair of force-balancing electrodes. To reduce the mass exciting along the sensing direction, we drive the mass by the same DC and opposite AC driving voltage on the oppositely placed comb-drives. It also features that the position sensing electric interference ins reduced. The mass is self-oscillated by the condition of limit cycle, so the mass is always oscillated in the natural frequency even if the natural frequency is varied by the environment and/or it has displacement-force nonlinear behavior. The gyroscope is fabricated on the silicon wafer by surface micromachining technology and the polysilicon is used as an active structure. The gyroscope has an active size of 700 by 600 micro meters, the thickness of the structure is 7 micron meters and the proof mass of 1 micro gram. To improve the resolution of the gyro, it is packaged in the 50 mili-torr vacuum package with a conditioning ASIC. Experimental results show that the gyroscope has the equivalent noise level of 0.1 deg/sec at 2 Hz, the bandwidth of 100 Hz, linearity of 1 percent FS and the sensing range of 90 deg/sec.

  10. Plasma evolution and dynamics in high-power vacuum-transmission-line post-hole convolutes

    Directory of Open Access Journals (Sweden)

    D. V. Rose

    2008-06-01

    Full Text Available Vacuum-post-hole convolutes are used in pulsed high-power generators to join several magnetically insulated transmission lines (MITL in parallel. Such convolutes add the output currents of the MITLs, and deliver the combined current to a single MITL that, in turn, delivers the current to a load. Magnetic insulation of electron flow, established upstream of the convolute region, is lost at the convolute due to symmetry breaking and the formation of magnetic nulls, resulting in some current losses. At very high-power operating levels and long pulse durations, the expansion of electrode plasmas into the MITL of such devices is considered likely. This work examines the evolution and dynamics of cathode plasmas in the double-post-hole convolutes used on the Z accelerator [R. B. Spielman et al., Phys. Plasmas 5, 2105 (1998PHPAEN1070-664X10.1063/1.872881]. Three-dimensional particle-in-cell (PIC simulations that model the entire radial extent of the Z accelerator convolute—from the parallel-plate transmission-line power feeds to the z-pinch load region—are used to determine electron losses in the convolute. The results of the simulations demonstrate that significant current losses (1.5 MA out of a total system current of 18.5 MA, which are comparable to the losses observed experimentally, could be caused by the expansion of cathode plasmas in the convolute regions.

  11. High-accuracy measurement of the emission spectrum of liquid xenon in the vacuum ultraviolet region

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Keiko, E-mail: fujii-keiko-nv@ynu.jp [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Endo, Yuya; Torigoe, Yui; Nakamura, Shogo [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Haruyama, Tomiyoshi; Kasami, Katsuyu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Mihara, Satoshi; Saito, Kiwamu; Sasaki, Shinichi [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); The Graduate School of Advanced Studies, Hayama, Kanagawa 240-0193 (Japan); Tawara, Hiroko [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan)

    2015-09-21

    The emission spectrum of cryogenic liquid xenon in the vacuum ultraviolet region was measured by irradiating liquid xenon with gamma-rays from a radioactive source. To achieve a high signal-to-noise ratio, we employed coincident photon counting. Additionally, the charge of the photo-sensor signals was measured to estimate the number of detected photons accurately. In addition, proper corrections were incorporated for the wavelength; response functions of the apparatus obtained using a low-pressure mercury lamp, and photon detection efficiencies of the optical system were considered. The obtained emission spectrum is found to be in the shape of a Gaussian function, with the center at 57,199±34 (stat.)±33 (syst.) cm{sup −1} (174.8±0.1 (stat.)±0.1 (syst.) nm) and the full width at half maximum of 3328±72 (stat.)±65 (syst.) cm{sup −1} (10.2±0.2 (stat.)±0.2 (sys.) nm). These results are the most accurate values obtained in terms of the data acquisition method and the calibration for the experimental system and provide valuable information regarding the high-precision instruments that employ a liquid-xenon scintillator.

  12. Design and Construction of a High Vacuum Surface Analysis Instrument to Study Chemistry at Nanoparticulate Surfaces

    Science.gov (United States)

    2011-04-21

    55 Figure 2.11 Drawing of the doser. (a) Vacuum side of flange and knife edge visible (b...a conical sealing edge on each of the flanges, also known as a knife edge, bites into the gasket resulting in a seal that is vacuum tight to...are basically miniature quadrupole mass spectrometers and are typically robust and relatively inexpensive. A Stanford Research Systems Residual Gas

  13. Development of spoilage bacterial community and volatile compounds in chilled beef under vacuum or high oxygen atmospheres.

    Science.gov (United States)

    Jääskeläinen, Elina; Hultman, Jenni; Parshintsev, Jevgeni; Riekkola, Marja-Liisa; Björkroth, Johanna

    2016-04-16

    Research into microbial community development and metabolism is essential to understand meat spoilage. Recent years have seen the emergence of powerful molecular techniques that are being used alongside conventional microbiology approaches. This enables more accurate studies on meat spoilage. The aim of this study was to investigate the influence of packaging (under vacuum and in high oxygen atmosphere) on the development of microbial communities and metabolic activities at 6 °C by using culture-dependent (cultivation, ribotyping) and culture-independent (amplicon sequencing) methods. At the beginning of shelf life, the microbial community mostly consisted of Carnobacterium and Lactobacillus. After two weeks of storage, Lactococcus and Lactobacillus were the dominant genera under vacuum and Leuconostoc in high oxygen meat packages. This indicates that oxygen favoured the genus Leuconostoc comprising only heterofermentative species and hence potential producers of undesirable compounds. Also the number of volatile compounds, such as diacetyl, 1-octen-3-ol and hexanoic acids, was higher in high oxygen packages than under vacuum packages. The beef in high oxygen atmosphere packaging was detected as spoiled in sensory evaluation over 10 days earlier than beef under vacuum packaging. Leuconostoc gelidum, Lactococcus piscium, Lactobacillus sakei and Lactobacillus algidus were the most common species of bacteria. The results obtained from identification of the isolates using ribotyping and amplicon sequencing correlated, except for L. algidus, which was detected in both types of packaging by amplicon sequencing, but only in vacuum packaged samples using the culture-based technique. This indicates that L. algidus grew, but was not cultivable in high oxygen beef using the Nordic Committee on Food Analysis standard method. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. 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, validationof the developed OSATS scale for vacuum...

  15. Vacuum ultra-violet damage and damage mitigation for plasma processing of highly porous organosilicate glass dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Marneffe, J.-F. de, E-mail: marneffe@imec.be; Lukaszewicz, M.; Porter, S. B.; Vajda, F.; Rutigliani, V.; Verdonck, P.; Baklanov, M. R. [IMEC v.z.w., 3001 Leuven (Belgium); Zhang, L.; Heyne, M.; El Otell, Z.; Krishtab, M. [IMEC v.z.w., 3001 Leuven (Belgium); Department of Chemistry, KULeuven, 3001 Leuven (Belgium); Goodyear, A.; Cooke, M. [Oxford Instruments Plasma Technology, BS49 4AP Bristol (United Kingdom)

    2015-10-07

    Porous organosilicate glass thin films, with k-value 2.0, were exposed to 147 nm vacuum ultra-violet (VUV) photons emitted in a Xenon capacitive coupled plasma discharge. Strong methyl bond depletion was observed, concomitant with a significant increase of the bulk dielectric constant. This indicates that, besides reactive radical diffusion, photons emitted during plasma processing do impede dielectric properties and therefore need to be tackled appropriately during patterning and integration. The detrimental effect of VUV irradiation can be partly suppressed by stuffing the low-k porous matrix with proper sacrificial polymers showing high VUV absorption together with good thermal and VUV stability. In addition, the choice of an appropriate hard-mask, showing high VUV absorption, can minimize VUV damage. Particular processing conditions allow to minimize the fluence of photons to the substrate and lead to negligible VUV damage. For patterned structures, in order to reduce VUV damage in the bulk and on feature sidewalls, the combination of both pore stuffing/material densification and absorbing hard-mask is recommended, and/or the use of low VUV-emitting plasma discharge.

  16. Ultra-high vacuum scanning thermal microscopy for nanometer resolution quantitative thermometry.

    Science.gov (United States)

    Kim, Kyeongtae; Jeong, Wonho; Lee, Woochul; Reddy, Pramod

    2012-05-22

    Understanding energy dissipation at the nanoscale requires the ability to probe temperature fields with nanometer resolution. Here, we describe an ultra-high vacuum (UHV)-based scanning thermal microscope (SThM) technique that is capable of quantitatively mapping temperature fields with ∼15 mK temperature resolution and ∼10 nm spatial resolution. In this technique, a custom fabricated atomic force microscope (AFM) cantilever, with a nanoscale Au-Cr thermocouple integrated into the tip of the probe, is used to measure temperature fields of surfaces. Operation in an UHV environment eliminates parasitic heat transport between the tip and the sample enabling quantitative measurement of temperature fields on metal and dielectric surfaces with nanoscale resolution. We demonstrate the capabilities of this technique by directly imaging thermal fields in the vicinity of a 200 nm wide, self-heated, Pt line. Our measurements are in excellent agreement with computational results-unambiguously demonstrating the quantitative capabilities of the technique. UHV-SThM techniques will play an important role in the study of energy dissipation in nanometer-sized electronic and photonic devices and the study of phonon and electron transport at the nanoscale.

  17. Development of a high-efficiency pulsed slow positron beam for measurements with orthopositronium in vacuum

    Science.gov (United States)

    Alberola, N.; Anthonioz, T.; Badertscher, A.; Bas, C.; Belov, A. S.; Crivelli, P.; Gninenko, S. N.; Golubev, N. A.; Kirsanov, M. M.; Rubbia, A.; Sillou, D.

    2006-05-01

    We have developed a high-efficiency pulsed slow positron beam for experiments with orthopositronium in vacuum. The new pulsing scheme is based on a double-gap coaxial buncher powered by an RF pulse of appropriate shape. The modulation of the positron velocity in the two gaps is used to adjust their time-of-flight to a target. This pulsing scheme allows to minimize non-linear aberrations in the bunching process and to efficiently compress positron pulses with an initial pulse duration ranging from ˜300 to 50 ns into bunches of 2.3 to 0.4 ns width, respectively, with a repetition period of 1 μs. The compression ratio achieved is ≃100, which is a factor 5 better than has been previously obtained with slow positron beams based on a single buncher. Requirements on the degree, to which the moderated positrons should be mono-energetic and on the precision of the waveform generation are presented. Possible applications of the new pulsed positron beam for measurements of thin films are discussed.

  18. High levels of polybrominated diphenyl ethers in vacuum cleaner dust from California fire stations.

    Science.gov (United States)

    Shen, Beverly; Whitehead, Todd P; McNeel, Sandra; Brown, F Reber; Dhaliwal, Joginder; Das, Rupali; Israel, Leslie; Park, June-Soo; Petreas, Myrto

    2015-04-21

    Firefighters are exposed to chemicals during fire events and may also experience chemical exposure in their fire stations. Dust samples from used vacuum cleaner bags were collected from 20 fire stations in California and analyzed for polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) using gas chromatography-mass spectrometry. Median dust concentrations were higher for PBDEs (e.g., 47 000 ng/g for BDE-209) than for PAHs (e.g., 220 ng/g for benzo[a]pyrene) or PCBs (e.g., 9.3 ng/g for PCB-180). BDE-209 concentrations in dust from California fire stations were among the highest of any previously documented homes or occupational settings in the world. We examined factors such as the frequency of emergency responses, the number of fire vehicles on site, and building age, but we could not account for the high levels of BDE-209 observed in fire station dust. Based on the findings of our pilot study, we hypothesize that possible sources of BDE-209 in fire stations include contaminated ash tracked back from fire events via boots, clothing, and other equipment as well as specialized equipment treated with BDE-209, including turnout gear and fire vehicles. We suggest possible follow-up studies to confirm these hypotheses.

  19. High rate deposition of transparent conducting oxide thin films by vacuum arc plasma evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Minami, Tadatsugu; Ida, Satoshi; Miyata, Toshihiro

    2002-09-02

    Transparent conducting oxide (TCO) thin films have been deposited at a high rate above 370 nm/min by vacuum arc plasma evaporation (VAPE) using sintered oxide fragments as the source material. It was found that the deposition rate of TCO films was strongly dependent on the deposition pressure, whereas the obtained electrical properties were relatively independent of the pressure. Resistivities of 5.6x10{sup -4} and 2.3x10{sup -4} {omega}{center_dot}cm and an average transmittance above 80% (with substrate included) in the visible range were obtained in Ga-doped ZnO (GZO) thin films deposited at 100 and 350 deg. C, respectively. In addition, a resistivity as low as 1.4x10{sup -4} {omega}{center_dot}cm and an average transmittance above 80% were also obtained in indium-tin-oxide (ITO) films deposited at 300 deg. C. The deposited TCO films exhibited uniform distributions of resistivity and thickness on large area substrates.

  20. Effect of deposition conditions on the characteristics of ZnO-SnO{sub 2} thin films deposited by filtered vacuum arc

    Energy Technology Data Exchange (ETDEWEB)

    Cetinoergue, E. [Electrical Discharge and Plasma Laboratory, Tel Aviv University, POB39040, Tel Aviv 69978 (Israel) and Cukurova University, Physics Department 01330 Adana (Turkey)]. E-mail: eda@eng.tau.ac.il; Goldsmith, S. [Electrical Discharge and Plasma Laboratory, Tel Aviv University, POB39040, Tel Aviv 69978 (Israel); School of Physics and Astronomy, Tel Aviv University, POB 39040, Tel Aviv 69978 (Israel); Boxman, R.L. [Electrical Discharge and Plasma Laboratory, Tel Aviv University, POB39040, Tel Aviv 69978 (Israel); Fleischman Faculty of Engineering, Tel Aviv University, POB 39040, Tel Aviv 69978 (Israel)

    2006-11-23

    ZnO-SnO{sub 2} thin films were deposited on microscope glass substrates by filtered vacuum arc deposition system. The effects of deposition conditions on film characteristics were studied using cathodes prepared with three different ratios of atomic concentrations of Zn to Sn. The micro and the macro properties of the films were investigated as a function of cathode composition, arc current, background oxygen deposition pressure, and deposition time. X-ray diffraction analysis indicated that deposited films were amorphous, independent of the cathode composition. The atomic concentration ratio of Zn to Sn in the film as determined by XPS analysis were 33.9%: 10.6%, 43.9%: 3.8%, 44.7%: 4.7% for 50%: 50%, 70%: 30% and 90%: 10% Zn-Sn alloy cathodes, respectively. Film transmission in the visible was 70 to 90%, affected by interference effects. The maximal and minimal values of the refractive index n and the absorption coefficient k in the visible were 2.11 to 1.94 and 0.07 to 0.001, respectively. The optical band gap was in the range of 3.13 to 3.59 eV. All films were highly resistive independent of deposition conditions used.

  1. Synthesis of DHA/EPA-rich phosphatidylcholine by immobilized phospholipase A1: effect of water addition and vacuum condition.

    Science.gov (United States)

    Li, Daoming; Qin, Xiaoli; Wang, Weifei; Li, Zhigang; Yang, Bo; Wang, Yonghua

    2016-08-01

    DHA/EPA-rich phosphatidylcholine (PC) was successfully synthesized by immobilized phospholipase A1 (PLA1)-catalyzed transesterification of PC and DHA/EPA-rich ethyl esters in a solvent-free system. Effects of reaction temperature, water addition and substrate mass ratio on the incorporation of DHA/EPA were evaluated using response surface methods (RSM). Water addition had most significant effect on the incorporation. Reaction temperature and substrate mass ratio, however, had no significant effect on the incorporation. The maximal incorporation was 19.09 % (24 h) under the following conditions: temperature 55.7 °C, water addition 1.1 wt % and substrate mass ratio (ethyl esters/PC) 6.8:1. Furthermore, effects of water addition (from 0 to 1.25 wt %) on DHA/EPA incorporation and the composition of products were further investigated. The immobilized PLA1 was more active when water addition was above 0.5 wt %. By monitoring the reaction processes with different water addition, a possible reaction scheme was proposed for transesterification of PC with DHA/EPA-rich ethyl esters. In summary, PC and sn2-lysophosphatidylocholine (LPC) were predominant in the mixtures at early stages of reaction, whereas sn1-LPC and glycerophosphocholine (GPC) predominant at later stages. The vacuum employed after 24 h significantly increased the incorporation of DHA/EPA and the composition of PC, and the highest incorporation (30.31 %) of DHA/EPA was obtained at 72 h and the yield of PC was 47.2 %.

  2. Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate--The effects of street sweeping, vacuum cleaning, high pressure washing, and milling.

    Science.gov (United States)

    Winston, Ryan J; Al-Rubaei, Ahmed M; Blecken, Godecke T; Viklander, Maria; Hunt, William F

    2016-03-15

    The surface infiltration rates (SIR) of permeable pavements decline with time as sediment and debris clog pore spaces. Effective maintenance techniques are needed to ensure the hydraulic functionality and water quality benefits of this stormwater control. Eight different small-scale and full-scale maintenance techniques aimed at recovering pavement permeability were evaluated at ten different permeable pavement sites in the USA and Sweden. Maintenance techniques included manual removal of the upper 2 cm of fill material, mechanical street sweeping, regenerative-air street sweeping, vacuum street sweeping, hand-held vacuuming, high pressure washing, and milling of porous asphalt. The removal of the upper 2 cm of clogging material did not significantly improve the SIR of concrete grid paves (CGP) and permeable interlocking concrete pavers (PICP) due to the inclusion of fines in the joint and bedding stone during construction, suggesting routine maintenance cannot overcome improper construction. For porous asphalt maintenance, industrial hand-held vacuum cleaning, pressure washing, and milling were increasingly successful at recovering the SIR. Milling to a depth of 2.5 cm nearly restored the SIR for a 21-year old porous asphalt pavement to like-new conditions. For PICP, street sweepers employing suction were shown to be preferable to mechanical sweepers; additionally, maintenance efforts may become more intensive over time to maintain a threshold SIR, as maintenance was not 100% effective at removing clogging material. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Dressing living organisms in a thin polymer membrane, the NanoSuit, for high-vacuum FE-SEM observation.

    Science.gov (United States)

    Ohta, Isao; Takaku, Yasuharu; Suzuki, Hiroshi; Ishii, Daisuke; Muranaka, Yoshinori; Shimomura, Masatsugu; Hariyama, Takahiko

    2014-08-01

    Scanning electron microscopy (SEM) has made remarkable progress and has become an essential tool for observing biological materials at microscopic level. However, various complex procedures have precluded observation of living organisms to date. Here, a new method is presented by which living organisms can be observed by field emission (FE)-SEM. Using this method, active movements of living animals were observed in vacuo (10(-5)-10(-7) Pa) by protecting them with a coating of thin polymer membrane, a NanoSuit, and it was found that the surface fine structure of living organisms is very different from that of traditionally fixed samples. After observation of mosquito larvae in the high vacuum of the FE-SEM, it was possible to rear them subsequently in normal culture conditions. This method will be useful for numerous applications, particularly for electron microscopic observations in the life sciences. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. High power spectrometer for the characterization of photovoltaic cells in a controlled atmosphere or vacuum

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Jørgensen, M.

    2003-01-01

    single monochromator grating. The photovoltaic sample under test is placed in a stainless-steel vacuum chamber allowing for operating pressures down to 10(-6) mbar equipped with a quartz window and electrical connections. The entire vacuum chamber was placed on a moving arm allowing for positioning...... in a selected part of the diffracted beam of the monochromator. The typical spectral resolution was 12 nm cm(-1) which gave bandwidths of 25 nm with a 2 cm sample width. The electrical characteristics of the photovoltaic device under test was measured using a source meter giving an experimental current...

  5. Technology handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is part of a series of publications that presents articles featuring the whole spectrum of vacuum physics. This particular volume presents materials that deal with technology concerns in vacuum mechanics. The first material talks about the utilization of ceramic materials in the construction of vacuum devices. The next paper details the application of vacuum physics in soldering and brazing process. The last article deals with the utilization of vacuum technology in high frequency heating. The book will be of great use to professionals involved

  6. High performance thermal insulation systems (HiPTI). Vacuum insulated products (VIP). Proceedings of the international conference and workshop

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, M.; Bertschinger, H.

    2001-07-01

    These are the proceedings of the International Conference and Workshop held at EMPA Duebendorf, Switzerland, in January 2001. The papers presented at the conference's first day included contributions on the role of high-performance insulation in energy efficiency - providing an overview of available technologies and reviewing physical aspects of heat transfer and the development of thermal insulation as well as the state of the art of glazing technologies such as high-performance and vacuum glazing. Also, vacuum-insulated products (VIP) with fumed silica, applications of VIP systems in technical building systems, nanogels, VIP packaging materials and technologies, measurement of physical properties, VIP for advanced retrofit solutions for buildings and existing and future applications for advanced low energy building are discussed. Finally, research and development concerning VIP for buildings are reported on. The workshops held on the second day covered a preliminary study on high-performance thermal insulation materials with gastight porosity, flexible pipes with high performance thermal insulation, evaluation of modern insulation systems by simulation methods as well as the development of vacuum insulation panels with a stainless steel envelope.

  7. VACUUM TRAP

    Science.gov (United States)

    Gordon, H.S.

    1959-09-15

    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  8. Treating osteoporotic vertebral compression fractures with intraosseous vacuum phenomena using high-viscosity bone cement via bilateral percutaneous vertebroplasty.

    Science.gov (United States)

    Guo, Dan; Cai, Jun; Zhang, Shengfei; Zhang, Liang; Feng, Xinmin

    2017-04-01

    Osteoporotic vertebral compression fractures with intraosseous vacuum phenomena could cause persistent back pains in patients, even after receiving conservative treatment. The aim of this study was to evaluate the efficacy of using high-viscosity bone cement via bilateral percutaneous vertebroplasty in treating patients who have osteoporotic vertebral compression fractures with intraosseous vacuum phenomena.Twenty osteoporotic vertebral compression fracture patients with intraosseous vacuum phenomena, who received at least 2 months of conservative treatment, were further treated by injecting high-viscosity bone cement via bilateral percutaneous vertebroplasty due to failure of conservative treatment. Treatment efficacy was evaluated by determining the anterior vertebral compression rates, visual analog scale (VAS) scores, and Oswestry disability index (ODI) scores at 1 day before the operation, on the first day of postoperation, at 1-month postoperation, and at 1-year postoperation.Three of 20 patients had asymptomatic bone cement leakage when treated via percutaneous vertebroplasty; however, no serious complications related to these treatments were observed during the 1-year follow-up period. A statistically significant improvement on the anterior vertebral compression rates, VAS scores, and ODI scores were achieved after percutaneous vertebroplasty. However, differences in the anterior vertebral compression rate, VAS score, and ODI score in the different time points during the 1-year follow-up period was not statistically significant (P > 0.05).Within the limitations of this study, the injection of high-viscosity bone cement via bilateral percutaneous vertebroplasty for patients who have osteoporotic vertebral compression fractures with intraosseous vacuum phenomena significantly relieved their back pains and improved their daily life activities shortly after the operation, thereby improving their life quality. In this study, the use of high-viscosity bone

  9. Microfabricated triggered vacuum switch

    Science.gov (United States)

    Roesler, Alexander W [Tijeras, NM; Schare, Joshua M [Albuquerque, NM; Bunch, Kyle [Albuquerque, NM

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  10. A 10 mK scanning tunneling microscope operating in ultra high vacuum and high magnetic fields.

    Science.gov (United States)

    Assig, Maximilian; Etzkorn, Markus; Enders, Axel; Stiepany, Wolfgang; Ast, Christian R; Kern, Klaus

    2013-03-01

    We present design and performance of a scanning tunneling microscope (STM) that operates at temperatures down to 10 mK providing ultimate energy resolution on the atomic scale. The STM is attached to a dilution refrigerator with direct access to an ultra high vacuum chamber allowing in situ sample preparation. High magnetic fields of up to 14 T perpendicular and up to 0.5 T parallel to the sample surface can be applied. Temperature sensors mounted directly at the tip and sample position verified the base temperature within a small error margin. Using a superconducting Al tip and a metallic Cu(111) sample, we determined an effective temperature of 38 ± 1 mK from the thermal broadening observed in the tunneling spectra. This results in an upper limit for the energy resolution of ΔE = 3.5 kBT = 11.4 ± 0.3 μeV. The stability between tip and sample is 4 pm at a temperature of 15 mK as demonstrated by topography measurements on a Cu(111) surface.

  11. A 10Â mK scanning tunneling microscope operating in ultra high vacuum and high magnetic fields

    Science.gov (United States)

    Assig, Maximilian; Etzkorn, Markus; Enders, Axel; Stiepany, Wolfgang; Ast, Christian R.; Kern, Klaus

    2013-03-01

    We present design and performance of a scanning tunneling microscope (STM) that operates at temperatures down to 10 mK providing ultimate energy resolution on the atomic scale. The STM is attached to a dilution refrigerator with direct access to an ultra high vacuum chamber allowing in situ sample preparation. High magnetic fields of up to 14 T perpendicular and up to 0.5 T parallel to the sample surface can be applied. Temperature sensors mounted directly at the tip and sample position verified the base temperature within a small error margin. Using a superconducting Al tip and a metallic Cu(111) sample, we determined an effective temperature of 38 ± 1 mK from the thermal broadening observed in the tunneling spectra. This results in an upper limit for the energy resolution of ΔE = 3.5kBT = 11.4 ± 0.3 μeV. The stability between tip and sample is 4 pm at a temperature of 15 mK as demonstrated by topography measurements on a Cu(111) surface.

  12. Integrating atomic layer deposition and ultra-high vacuum physical vapor deposition for in situ fabrication of tunnel junctions.

    Science.gov (United States)

    Elliot, Alan J; Malek, Gary A; Lu, Rongtao; Han, Siyuan; Yu, Haifeng; Zhao, Shiping; Wu, Judy Z

    2014-07-01

    Atomic Layer Deposition (ALD) is a promising technique for growing ultrathin, pristine dielectrics on metal substrates, which is essential to many electronic devices. Tunnel junctions are an excellent example which require a leak-free, ultrathin dielectric tunnel barrier of typical thickness around 1 nm between two metal electrodes. A challenge in the development of ultrathin dielectric tunnel barriers using ALD is controlling the nucleation of dielectrics on metals with minimal formation of native oxides at the metal surface for high-quality interfaces between the tunnel barrier and metal electrodes. This poses a critical need for integrating ALD with ultra-high vacuum (UHV) physical vapor deposition. In order to address these challenges, a viscous-flow ALD chamber was designed and interfaced to an UHV magnetron sputtering chamber via a load lock. A sample transportation system was implemented for in situ sample transfer between the ALD, load lock, and sputtering chambers. Using this integrated ALD-UHV sputtering system, superconductor-insulator-superconductor (SIS) Nb-Al/Al2O2/Nb Josephson tunnel junctions were fabricated with tunnel barriers of thickness varied from sub-nm to ~1 nm. The suitability of using an Al wetting layer for initiation of the ALD Al2O3 tunnel barrier was investigated with ellipsometry, atomic force microscopy, and electrical transport measurements. With optimized processing conditions, leak-free SIS tunnel junctions were obtained, demonstrating the viability of this integrated ALD-UHV sputtering system for the fabrication of tunnel junctions and devices comprised of metal-dielectric-metal multilayers.

  13. Integrating atomic layer deposition and ultra-high vacuum physical vapor deposition for in situ fabrication of tunnel junctions

    Science.gov (United States)

    Elliot, Alan J.; Malek, Gary A.; Lu, Rongtao; Han, Siyuan; Yu, Haifeng; Zhao, Shiping; Wu, Judy Z.

    2014-07-01

    Atomic Layer Deposition (ALD) is a promising technique for growing ultrathin, pristine dielectrics on metal substrates, which is essential to many electronic devices. Tunnel junctions are an excellent example which require a leak-free, ultrathin dielectric tunnel barrier of typical thickness around 1 nm between two metal electrodes. A challenge in the development of ultrathin dielectric tunnel barriers using ALD is controlling the nucleation of dielectrics on metals with minimal formation of native oxides at the metal surface for high-quality interfaces between the tunnel barrier and metal electrodes. This poses a critical need for integrating ALD with ultra-high vacuum (UHV) physical vapor deposition. In order to address these challenges, a viscous-flow ALD chamber was designed and interfaced to an UHV magnetron sputtering chamber via a load lock. A sample transportation system was implemented for in situ sample transfer between the ALD, load lock, and sputtering chambers. Using this integrated ALD-UHV sputtering system, superconductor-insulator-superconductor (SIS) Nb-Al/Al2O2/Nb Josephson tunnel junctions were fabricated with tunnel barriers of thickness varied from sub-nm to ˜1 nm. The suitability of using an Al wetting layer for initiation of the ALD Al2O3 tunnel barrier was investigated with ellipsometry, atomic force microscopy, and electrical transport measurements. With optimized processing conditions, leak-free SIS tunnel junctions were obtained, demonstrating the viability of this integrated ALD-UHV sputtering system for the fabrication of tunnel junctions and devices comprised of metal-dielectric-metal multilayers.

  14. Stable, high quantum efficiency silicon photodiodes for vacuum-UV applications

    Science.gov (United States)

    Korde, Raj; Canfield, L. Randall; Wallis, Brad

    1988-01-01

    Silicon photodiodes have been developed by defect-free phosphorus diffusion having practically no carrier recombination at the SiSiO2 interface or in the front diffused region. The quantum efficiency of these photodiodes was found to be around 120 percent at 100 nm. Unlike the previously tested silicon photodiodes, the developed photodiodes exhibit extremely stable quantum efficiency over extended periods of time. The possibility of using these photodiodes as vacuum ultraviolet detector standards is being currently investigated.

  15. Additive manufacturing of magnetic shielding and ultra-high vacuum flange for cold atom sensors.

    Science.gov (United States)

    Vovrosh, Jamie; Voulazeris, Georgios; Petrov, Plamen G; Zou, Ji; Gaber, Youssef; Benn, Laura; Woolger, David; Attallah, Moataz M; Boyer, Vincent; Bongs, Kai; Holynski, Michael

    2018-01-31

    Recent advances in the understanding and control of quantum technologies, such as those based on cold atoms, have resulted in devices with extraordinary metrological performance. To realise this potential outside of a lab environment the size, weight and power consumption need to be reduced. Here we demonstrate the use of laser powder bed fusion, an additive manufacturing technique, as a production technique relevant to the manufacture of quantum sensors. As a demonstration we have constructed two key components using additive manufacturing, namely magnetic shielding and vacuum chambers. The initial prototypes for magnetic shields show shielding factors within a factor of 3 of conventional approaches. The vacuum demonstrator device shows that 3D-printed titanium structures are suitable for use as vacuum chambers, with the test system reaching base pressures of 5 ± 0.5 × 10 -10 mbar. These demonstrations show considerable promise for the use of additive manufacturing for cold atom based quantum technologies, in future enabling improved integrated structures, allowing for the reduction in size, weight and assembly complexity.

  16. A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging

    Directory of Open Access Journals (Sweden)

    Zhenyu Luo

    2014-12-01

    Full Text Available This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS vacuum packaging. An approach to maintaining high-vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for vacuum packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.

  17. Influence of Crucible Materials on High-temperature Properties of Vacuum-melted Nickel-chromium-cobalt Alloy

    Science.gov (United States)

    Decker, R F; Rowe, John P; Freeman, J W

    1957-01-01

    A study of the effect of induction-vacuum-melting procedure on the high-temperature properties of a titanium-and-aluminum-hardened nickel-base alloy revealed that a major variable was the type of ceramic used as a crucible. Reactions between the melt and magnesia or zirconia crucibles apparently increased high-temperature properties by introducing small amounts of boron or zirconium into the melts. Heats melted in alumina crucibles had relatively low rupture life and ductility at 1,600 F and cracked during hot-working as a result of deriving no boron or zirconium from the crucible.

  18. Influence of drying conditions on the effective diffusivity and activation energy during convective air and vacuum drying of pumpkin

    Directory of Open Access Journals (Sweden)

    Liliana SEREMET (CECLU

    2015-12-01

    Full Text Available The main purpose of the work is to investigate the efficiency of convective air and vacuum processing on pumpkin drying kinetics. The pumpkin samples were of two different geometrical shapes (cylinder and cube and were dried in a laboratory scale hot air dryer using some specific parameters (constant air velocity of 1.0 m/s, three different temperatures 50, 60 and 70ºC suited to relative humidity (RH values of 9.8, 6.5, and 5.4% respectively. The vacuum drying was led at constant pressures of 5 kPa and accordance temperatures of 50, 60 and 70ºC. Moisture transfer from pumpkin slices was described by applying Fick’s diffusion model. Temperature dependence of the effective diffusivity was described by the Arrhenius-type equation. Cylindrical samples have a slightly better behaviour compared to cubic samples, due to the disposition of the tissues, and the mass and thermic transfer possibilities. Analysing the results of both drying methods, it was deduced that the most efficient method is convective air drying at 70ºC.

  19. Invariant vacuum

    Science.gov (United States)

    Robles-Pérez, Salvador

    2017-11-01

    We apply the Lewis-Riesenfeld invariant method for the harmonic oscillator with time dependent mass and frequency to the modes of a charged scalar field that propagates in a curved, homogeneous and isotropic spacetime. We recover the Bunch-Davies vacuum in the case of a flat DeSitter spacetime, the equivalent one in the case of a closed DeSitter spacetime and the invariant vacuum in a curved spacetime that evolves adiabatically. In the three cases, it is computed the thermodynamical magnitudes of entanglement between the modes of the particles and antiparticles of the invariant vacuum, and the modification of the Friedmann equation caused by the existence of the energy density of entanglement. The amplitude of the vacuum fluctuations are also computed.

  20. 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)

  1. Vacuum II

    CERN Document Server

    Franchetti, G

    2013-01-01

    This paper continues the presentation of pumps begun in ‘Vacuum I’. The main topic here is gauges and partial-pressure measurements. Starting from the kinetics of gases, the various strategies for measuring vacuum pressures are presented at an introductory level, with some reference to hardware devices. Partial-pressure measurement techniques are introduced, showing that the principles of ion selection have a direct similarity to particle dynamics in accelerators.

  2. A vacuum double-crystal spectrometer for reference-free highly charged ions X-ray spectroscopy

    CERN Document Server

    Amaro, P; Schlesser, S; Gumberidze, Alexandre; Kessler, Ernest G; Henins, Albert; Bigot, E -O Le; Trassinelli, M; Isac, Jean-Michel; Travers, Pascal; Guerra, Mauro; Santos, J P; Indelicato, Paul

    2012-01-01

    We have built a vacuum double crystal spectrometer, which coupled to an electron-cyclotron resonance ion source, allows to measure low-energy x-ray transitions in highly-charged ions with accuracies of the order of a few parts per million. We describe in detail the instrument and its performances. Furthermore, we present a few spectra of transitions in Ar$^{14+}$, Ar$^{15+}$ and Ar$^{16+}$. We have developed an \\emph{ab initio} simulation code that allows us to obtain accurate line profiles. It can reproduce experimental spectra with unprecedented accuracy. The quality of the profiles allows the direct determination of line width.

  3. A 'NanoSuit' surface shield successfully protects organisms in high vacuum: observations on living organisms in an FE-SEM.

    Science.gov (United States)

    Takaku, Yasuharu; Suzuki, Hiroshi; Ohta, Isao; Tsutsui, Takami; Matsumoto, Haruko; Shimomura, Masatsugu; Hariyama, Takahiko

    2015-03-07

    Although extremely useful for a wide range of investigations, the field emission scanning electron microscope (FE-SEM) has not allowed researchers to observe living organisms. However, we have recently reported that a simple surface modification consisting of a thin extra layer, termed 'NanoSuit', can keep organisms alive in the high vacuum (10(-5) to 10(-7) Pa) of the SEM. This paper further explores the protective properties of the NanoSuit surface-shield. We found that a NanoSuit formed with the optimum concentration of Tween 20 faithfully preserves the integrity of an organism's surface without interfering with SEM imaging. We also found that electrostatic charging was absent as long as the organisms were alive, even if they had not been coated with electrically conducting materials. This result suggests that living organisms possess their own electrical conductors and/or rely on certain properties of the surface to inhibit charging. The NanoSuit seems to prolong the charge-free condition and increase survival time under vacuum. These findings should encourage the development of more sophisticated observation methods for studying living organisms in an FE-SEM. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  4. A ‘NanoSuit’ surface shield successfully protects organisms in high vacuum: observations on living organisms in an FE-SEM

    Science.gov (United States)

    Takaku, Yasuharu; Suzuki, Hiroshi; Ohta, Isao; Tsutsui, Takami; Matsumoto, Haruko; Shimomura, Masatsugu; Hariyama, Takahiko

    2015-01-01

    Although extremely useful for a wide range of investigations, the field emission scanning electron microscope (FE-SEM) has not allowed researchers to observe living organisms. However, we have recently reported that a simple surface modification consisting of a thin extra layer, termed ‘NanoSuit’, can keep organisms alive in the high vacuum (10−5 to 10−7 Pa) of the SEM. This paper further explores the protective properties of the NanoSuit surface-shield. We found that a NanoSuit formed with the optimum concentration of Tween 20 faithfully preserves the integrity of an organism's surface without interfering with SEM imaging. We also found that electrostatic charging was absent as long as the organisms were alive, even if they had not been coated with electrically conducting materials. This result suggests that living organisms possess their own electrical conductors and/or rely on certain properties of the surface to inhibit charging. The NanoSuit seems to prolong the charge-free condition and increase survival time under vacuum. These findings should encourage the development of more sophisticated observation methods for studying living organisms in an FE-SEM. PMID:25631998

  5. Vacuum phenomenon.

    Science.gov (United States)

    Yanagawa, Youichi; Ohsaka, Hiromichi; Jitsuiki, Kei; Yoshizawa, Toshihiko; Takeuchi, Ikuto; Omori, Kazuhiko; Oode, Yasumasa; Ishikawa, Kouhei

    2016-08-01

    This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: if an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.

  6. Large-Area and High-Throughput PDMS Microfluidic Chip Fabrication Assisted by Vacuum Airbag Laminator

    Directory of Open Access Journals (Sweden)

    Shuting Xie

    2017-07-01

    Full Text Available One of the key fabrication steps of large-area microfluidic devices is the flexible-to-hard sheet alignment and pre-bonding. In this work, the vacuum airbag laminator (VAL which is commonly used for liquid crystal display (LCD production has been applied for large-area microfluidic device fabrication. A straightforward, efficient, and low-cost method has been achieved for 400 × 500 mm2 microfluidic device fabrication. VAL provides the advantages of precise alignment and lamination without bubbles. Thermal treatment has been applied to achieve strong PDMS–glass and PDMS–PDMS bonding with maximum breakup pressure of 739 kPa, which is comparable to interference-assisted thermal bonding method. The fabricated 152 × 152 mm2 microfluidic chip has been successfully applied for droplet generation and splitting.

  7. High reflectivity Ohmic contacts to n-GaN utilizing vacuum annealed aluminum

    KAUST Repository

    Yonkee, Benjamin P.

    2017-10-31

    Ohmic contacts to both c-plane and (202 ̅1 ̅) n-GaN are demonstrated using a pure aluminum layer which was vacuum annealed to prevent oxidation. Specific contact resistivities of 4.4 × 10-7 and 2.3 × 10-5 Ωcm2 were obtained without annealing for c-plane and (202 ̅1 ̅ ) samples respectively. A reflectivity of over 85% at 450 nm was measured for both samples. After a 300 °C anneal specific contact resistivities of 1.5 × 10-7 and 1.8 × 10-7 Ωcm2 were obtained for c-plane and (202 ̅1 ̅ ) samples respectively and the reflectivities remained higher than 80%.

  8. Improved design of a high-voltage vacuum-insulator interface

    Directory of Open Access Journals (Sweden)

    W. A. Stygar

    2005-05-01

    Full Text Available We have conducted a series of experiments designed to measure the flashover strength of various azimuthally symmetric 45° vacuum-insulator configurations. The principal objective of the experiments was to identify a configuration with a flashover strength greater than that of the standard design, which consists of a 45° polymethyl-methacrylate (PMMA insulator between flat electrodes. The thickness d and circumference C of the insulators tested were held constant at 4.318 and 95.74 cm, respectively. The peak voltage applied to the insulators ranged from 0.8 to 2.2 MV. The rise time of the voltage pulse was 40–60 ns; the effective pulse width [as defined in Phys. Rev. ST Accel. Beams 7, 070401 (2004PRABFM1098-440210.1103/PhysRevSTAB.7.070401] was on the order of 10 ns. Experiments conducted with flat aluminum electrodes demonstrate that the flashover strength of a crosslinked polystyrene (Rexolite insulator is (18±7% higher than that of PMMA. Experiments conducted with a Rexolite insulator and an anode plug, i.e., an extension of the anode into the insulator, demonstrate that a plug can increase the flashover strength by an additional (44±11%. The results are consistent with the Anderson model of anode-initiated flashover, and confirm previous measurements. It appears that a Rexolite insulator with an anode plug can, in principle, increase the peak electromagnetic power that can be transmitted across a vacuum interface by a factor of [(1.18(1.44]^{2}=2.9 over that which can be achieved with the standard design.

  9. Test of the beam effect on vacuum arc occurrence in a high-gradient accelerating structure for the CLIC project

    CERN Document Server

    AUTHOR|(CDS)2130409; Gagliardi, Martino

    A new generation of lepton colliders capable of reaching TeV energies is pres- ently under development, and to succeed in this task it is necessary to show that the technology for such a machine is available. The Compact Linear Collider (CLIC) is a possible design option among the future lepton collider projects. It consists of two normal-conducting linacs. Accelerating structures with a gradient of the order of 100 MV/m are necessary to reach the required high energies within a reasonable machine length. One of the strictest require- ments for such accelerating structures is a relatively low occurrence of vacuum arcs. CLIC prototype structures have been tested in the past, but only in absence of beam. In order to proof the feasibility of the high gradient technology for building a functional collider, it is necessary to understand the effect of the beam presence on the vacuum breakdowns. Tests of this type have never been performed previously. The main goal of this work is to provide a first measurement of t...

  10. Absorption spectroscopy of xenon and ethylene-noble gas mixtures at high pressure: Towards Bose-Einstein condensation of vacuum ultraviolet photons

    CERN Document Server

    Wahl, Christian; Schmitt, Julian; Vewinger, Frank; Christopoulos, Stavros; Weitz, Martin

    2016-01-01

    Bose-Einstein condensation is a phenomenon well known for material particles as cold atomic gases, and this concept has in recent years been extended to photons confined in microscopic optical cavities. Essential for the operation of such a photon condensate is a thermalization mechanism that conserves the average particle number, as in the visible spectral regime can be realized by subsequent absorption re-emission processes in dye molecules. Here we report on the status of an experimental effort aiming at the extension of the concept of Bose-Einstein condensation of photons towards the vacuum ultraviolet spectral regime, with gases at high pressure conditions serving as a thermalization medium for the photon gas. We have recorded absorption spectra of xenon gas at up to 30 bar gas pressure of the $5p^6 - 5p^56s$ transition with a wavelength close to 147 nm. Moreover, spectra of ethylene noble gas mixtures between 155 and 180 nm wavelength are reported.

  11. Advanced window incorporating vacuum glazing

    Science.gov (United States)

    Asano, Osamu; Misonou, Masao; Kato, Hidemi; Nagasaka, Shigeki

    1999-10-01

    Vacuum glazing product named SPACIATM, being an unique product with very high levels of thermal insulation properties in a very small thickness, is described in detail. The construction and manufacturing process of SPACIATM are reported. Its design, which was originally established by R.E. Collins et al. of the University of Sydney, has been adjusted in order to meet the requirements of the Japanese market and the requirements of mass production process. SPACIATM is found to have several unique features including airborne sound insulation as well as thermal insulation. Energy required for air conditioning was simulated for Japanese houses with various glazings, and it was revealed that SPACIATM could save the energy efficiently. Finally, hybrid IG unit, where vacuum glazing is incorporated into a conventional IG unit, is proposed for further improvement of thermal insulation.

  12. Electrical and structural R&D activities on high voltage dc solid insulator in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Pilan, N., E-mail: nicola.pilan@igi.cnr.it [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Marcuzzi, D.; Rizzolo, A.; Grando, L.; Gambetta, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Rosa, S. Dalla [Umicore – Italbras S.p.A., Strada del Balsego, n.6, 36100 Vicenza (Italy); Kraemer, V.; Quirmbach, T. [FRIATEC Ceramics Division, Steinzeugstrasse 50, 68229 Mannheim (Germany); Chitarin, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Gobbo, R.; Pesavento, G. [DII, Università di Padova, v. Gradenigo 6/A, I-35131 Padova (Italy); De Lorenzi, A.; Lotto, L.; Rizzieri, R.; Fincato, M.; Romanato, L.; Trevisan, L.; Cervaro, V.; Franchin, L. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2015-10-15

    Highlights: • A thorough R&D activity on the MITICA post insulator prototypes is being carried out. • The design has been numerically verified considering both mechanical and electrical aspects. • Experimental validation has been started, with positive results in both involved fields. • Alternative design solutions thickness have been proposed and successfully tested. - Abstract: This paper describes the R&D work performed in support of the design of the alumina insulators for the MITICA Neutral Beam Injector. The ceramic insulators are critical elements, both from the structural and electrical point of view, of the 1 MV electrostatic accelerator of the MITICA injector, as they are required to sustain both the mechanical loads due to the cantilevered weight of the ion source and the high electric field between the accelerator grids. This paper presents the results of numerical simulations and experimental tests on prototypes that have been carried out to validate the insulator design under realistic operating conditions.

  13. Tetrasilane and digermane for the ultra-high vacuum chemical vapor deposition of SiGe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hart, John, E-mail: hartjt@udel.edu [Department of Electrical Engineering, University of Delaware, 140 Evans Hall, Newark, DE 19716 (United States); Hazbun, Ramsey; Eldridge, David; Hickey, Ryan [Department of Electrical Engineering, University of Delaware, 140 Evans Hall, Newark, DE 19716 (United States); Fernando, Nalin [Department of Physics, University of New Mexico, MSC 3D, P.O. Box 30001, Las Cruces, New Mexico 88003-8001 (United States); Adam, Thomas [College of Nanoscale Science and Engineering, SUNY, New York 12203 (United States); Zollner, Stefan [Department of Physics, University of New Mexico, MSC 3D, P.O. Box 30001, Las Cruces, New Mexico 88003-8001 (United States); Kolodzey, James [Department of Electrical Engineering, University of Delaware, 140 Evans Hall, Newark, DE 19716 (United States)

    2016-04-01

    Tetrasilane and digermane were used to grow epitaxial silicon germanium layers on silicon substrates in a commercial ultra-high vacuum chemical vapor deposition tool. Films with concentrations up to 19% germanium were grown at temperatures from 400 °C to 550 °C. For all alloy compositions, the growth rates were much higher compared to using mono-silane and mono-germane. The quality of the material was assessed using X-ray diffraction, atomic force microscopy, and spectroscopic ellipsometry; all indicating high quality epitaxial films with low surface roughness suitable for commercial applications. Studies of the decomposition kinetics with regard to temperature were performed, revealing an unusual growth rate maximum between the high and low temperature deposition regimes. - Highlights: • Higher order precursors tetrasilane and digermane • Low temperature deposition • Thorough film characterization with temperature • Arrhenius growth rate peak.

  14. Study of sorption behavior, shelf life and colour kinetics of vacuum puffed honey powder at accelerated storage conditions.

    Science.gov (United States)

    Devi, K Deepika; Paul, Sanjib Kr; Sahu, Jatindra K

    2016-05-01

    In the study, the storage life of vacuum puffed honey powder at accelerated storage environment (90 % relative humidity and 36 °C) was computed by determining the sticky-point moisture content as the critical parameter of the honey powder. The value of monolayer moisture content in the GAB model was calculated to be 0.081 kg water/kg dry solids by fitting water activity and moisture sorption data. Shelf life of the honey powder was predicted to be 222 days when the powder was packaged in aluminum foil-laminated polyethylene pouches with permeability value of 5.427X10(-8) kg/m(2)//day/Pa. Actual shelf life of honey powder was experimentally determined as 189 days and analysis of mean relative percent derivation modulus (Rd) and root mean square (RMS) established the accuracy and acceptability of the technique for the prediction of shelf life of honey powder. Overall colour deviation pattern followed first order reaction kinetics with rate constant (k1) as 0.037 day(-1). This study revealed overall colour difference of 18.1 till the end of shelf life with drastic change during initial storage period.

  15. 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...

  16. Control of the Polarization of a Vacuum-Ultraviolet, High-Gain, Free-Electron Laser

    Directory of Open Access Journals (Sweden)

    Enrico Allaria

    2014-12-01

    Full Text Available The two single-pass, externally seeded free-electron lasers (FELs of the FERMI user facility are designed around Apple-II-type undulators that can operate at arbitrary polarization in the vacuum ultraviolet-to-soft x-ray spectral range. Furthermore, within each FEL tuning range, any output wavelength and polarization can be set in less than a minute of routine operations. We report the first demonstration of the full output polarization capabilities of FERMI FEL-1 in a campaign of experiments where the wavelength and nominal polarization are set to a series of representative values, and the polarization of the emitted intense pulses is thoroughly characterized by three independent instruments and methods, expressly developed for the task. The measured radiation polarization is consistently >90% and is not significantly spoiled by the transport optics; differing, relative transport losses for horizontal and vertical polarization become more prominent at longer wavelengths and lead to a non-negligible ellipticity for an originally circularly polarized state. The results from the different polarimeter setups validate each other, allow a cross-calibration of the instruments, and constitute a benchmark for user experiments.

  17. Fractal model for evaluating heat transfer of high temperature porous corundum shell in vacuum investment casting

    Directory of Open Access Journals (Sweden)

    WAN Xin

    2006-02-01

    Full Text Available Under vacuum, heat transfer in porous corundum shell of investment casting depends on the characteristics of the solid materials and the spatial arrangement of solids and pores. In this study, we present a modified fractal approach to model the pore structure of corundum shell and to describe its influence on the thermal conductivity. We assumed that there is no heat convection in the shell. A sectioned view of porous corundum shell was studied and used to describe the geometric structure and to calculate the fractal dimension d. Based on the fractal dimension d, we obtained the relationship between volumetric solid content and pore arrangement in different measure scales. A heat transfer model was thus established using a network of resistors in which we applied an equivalent approach to calculate the effective thermal conductivity of real porous corundum shell that include the effects of heat conduction and heat radiation of solid. From the obtained results we discuss these effects on the effective thermal conductivity including the scale of measurement, the structure of pore and the temperature. At last these results were compared with other empirical model, which computed by assuming even porosity in which effect of pore structure was not being considered. Though the thermal conductivity calculated essentially in agreement with that obtained from empirical model, model used in this study is more close to the real heat transfer process.

  18. Vacuum Valve

    CERN Multimedia

    1974-01-01

    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  19. High heat loading properties of vacuum plasma spray tungsten coatings on reduced activation ferritic/martensitic steel

    Science.gov (United States)

    Tokunaga, K.; Hotta, T.; Araki, K.; Miyamoto, Y.; Fujiwara, T.; Hasegawa, M.; Nakamura, K.; Ezato, K.; Suzuki, S.; Enoeda, M.; Akiba, M.; Nagasaka, T.; Kasada, R.; Kimura, A.

    2013-07-01

    High density W coatings on reduced activation ferritic martensitic steel (RAF/M) have been produced by Vacuum Plasma Spraying technique (VPS) and heat flux experiments on them have been carried out to evaluate their possibility as a plasma-facing armor in a fusion device. In addition, quantitative analyses of temperature profile and thermal stress have been carried out using the finite element analysis (FEA) to evaluate its thermal properties. No cracks or exfoliation has been formed by steady state and cyclic heat loading experiments under heat loading at 700 °C of surface temperature. In addition, stress distribution and maximum stress between interface of VPS-W and RAF/M have been obtained by FEA. On the other hand, exfoliation has occurred at interlayer of VPS-W coatings near the interface between VPS-W and RAF/M at 1300 °C of surface temperature by cyclic heat loading.

  20. Growth of high-quality CuInSe sub 2 polycrystalline films by magnetron sputtering and vacuum selenization

    CERN Document Server

    Xie Da Tao; Wang Li; Zhu Feng; Quan Sheng Wen; Meng Tie Jun; Zhang Bao Cheng; Chen J

    2002-01-01

    High-quality CuInSe sub 2 thin films have been prepared using a two stages process. Cu and In were co-deposited onto glass substrates by magnetron sputtering method to produce a predominant Cu sub 1 sub 1 In sub 9 phase. The alloy films were selenised and annealed in vacuum at different temperature in the range of 200-500 degree C using elemental selenium in a closed graphite box. X-ray diffraction and scanning electron microscopy were used to characterize the films. It is found that the polycrystalline and single-phase CuInSe sub 2 films were uniform and densely packed with a grain size of about 3.0 mu m

  1. Plume splitting and oscillatory behavior in transient plasmas generated by high-fluence laser ablation in vacuum

    Science.gov (United States)

    Focsa, C.; Gurlui, S.; Nica, P.; Agop, M.; Ziskind, M.

    2017-12-01

    We present a short overview of studies performed in our research groups over the last decade on the characterization of transient plasma plumes generated by laser ablation in various temporal regimes, from nanosecond to femtosecond. New results are also presented along with this overview, both being placed in the context of similar studies performed by other investigators. Optical (fast gate intensified CCD camera imaging and space- and time-resolved emission spectroscopy) and electrical (mainly Langmuir probe) methods have been applied to experimentally explore the dynamics of the plasma plume and its constituents. Peculiar effects as plume splitting and sharpening or oscillations onset have been evidenced in vacuum at high laser fluence. New theoretical approaches have been developed to account for the experimental observations.

  2. Flow injection of liquid samples to a mass spectrometer with ionization under vacuum conditions: a combined ion source for single-photon and electron impact ionization.

    Science.gov (United States)

    Schepler, Claudia; Sklorz, Martin; Passig, Johannes; Famiglini, Giorgio; Cappiello, Achille; Zimmermann, Ralf

    2013-09-01

    Electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photo-ionization (APPI) are the most important techniques for the ionization of liquid samples. However, working under atmospheric pressure conditions, all these techniques involve some chemical rather than purely physical processes, and therefore, side reactions often yield to matrix-dependent ionization efficiencies. Here, a system is presented that combines both soft single-photon ionization (SPI) and hard 70 eV electron impact ionization (EI) of dissolved compounds under vacuum conditions. A quadrupole mass spectrometer was modified to enable direct EI, a technique developed by Cappiello et al. to obtain library-searchable EI mass spectra as well as soft SPI mass spectra of sample solutions. An electron beam-pumped rare gas excimer lamp working at 126 nm was used as well as a focusable vacuum UV light source for single-photon ionization. Both techniques, EI and SPI, were applied successfully for flow injection experiments providing library-matchable EI fragment mass spectra and soft SPI mass spectra, showing dominant signals for the molecular ion. Four model compounds were analyzed: hexadecane, propofol, chlorpropham, and eugenol, with detection limits in the picomolar range. This novel combination of EI and SPI promises great analytical benefits, thanks to the possibility of combining database alignment for EI data and molecular mass information provided by SPI. Possible applications for the presented ionization technology system are a matrix-effect-free detection and a rapid screening of different complex mixtures without time-consuming sample preparation or separation techniques (e.g., for analysis of reaction solutions in combinatorial chemistry) or a switchable hard (EI) and soft (SPI) MS method as detection step for liquid chromatography.

  3. 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.

  4. 75 FR 76019 - Compliance Policy Guide Sec. 390.500 Definition of “High-Voltage Vacuum Switch”-21 CFR 1002.61(a...

    Science.gov (United States)

    2010-12-07

    ... HUMAN SERVICES Food and Drug Administration Compliance Policy Guide Sec. 390.500 Definition of ``High... the withdrawal of Compliance Policy Guide Sec. 390.500 Definition of ``High-Voltage Vacuum Switch... CONTACT: Sean M. Boyd, Center for Devices and Radiological Health, Office of Communication, Education, and...

  5. Development of Sub-Ischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

    Science.gov (United States)

    2013-10-01

    artificial leak in vacuum, and allowing the LimbLogic electrical system to activate in order to return vacuum to 17 inHg. Using the four-post design, the...Identifying the apex of the muscle belly in the software should be a good place to start. Task 12 Create education materials Task 12a Consult with

  6. High signal intensity on T1-weighted MR image related to vacuum cleft in the intervertebral disk; clinical and phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Tae Gyun; Kim, Yong Sun; Chang, Yongmin; Lee, Sang Kwon; Kim, Young Hwan; Ryeom, Hyun Kyu; Lee, Jong Min; Lee, Chang Hyon; Kim, Tae Hun [Kyungpook National Univ. College of Medicine , Taegu (Korea, Republic of); Suh, Kyung Jin [Suh and Joo MRI Center, Taegu (Korea, Republic of)

    2000-12-01

    To determine the possible mechanism by which an area of high signal intensity appears on T1-weighted MR images adjacent to a vacuum cleft in intervertebral disks. We analyzed a total of 14 disks in nine patients in whom a vacuum cleft with T1-signal hyperintensity was observed. Lesions were present from T11-12 to L5-S1 using a 1.5-T whole-body imager, sagittal spine-echo T1-weighted and gradient-echo images (flip angle, 20 .deg. and 60 .deg.) were obtained. In order to identify the vacuum cleft, using plain radiographs in all patients and CT scans in two were also obtained. A 3% agar-gel block containing empty slits to form a magnetic susceptibility difference, a phantom was designed. The air spaces were 1.6mm in thickness, 25mm in width, and 20 to 25mm in depth with 1.6-mm spacing. In all patients, vacuum clefts were confirmed by plain radiographs and CT scans. At the level containing air, T1-weighted images (both spin-echo and gradient-echo) showed a signal void resulting from the intervertebral disk vacuum cleft. A hyperintense band adjacent to the vacuum cleft was, however, observed. A gradient-echo image with a 60 .deg. flip angle showed a brighter signal intensity than one with a 20 .deg. angle. Our phantom study gave the same results. The magnetic susceptibility artifact may be responsible for the T1-signal hyperintensity observed adjacent to the vacuum cleft in intervertebral disks. In addition, in order to generate signal hyperintensity, the desiccating disk material must contain a certain amount of water molecules.

  7. High-risk lesions diagnosed at MRI-guided vacuum-assisted breast biopsy: can underestimation be predicted?

    Energy Technology Data Exchange (ETDEWEB)

    Crystal, Pavel [Mount Sinai Hospital, University Health Network, Division of Breast Imaging, Toronto, ON (Canada); Mount Sinai Hospital, Toronto, ON (Canada); Sadaf, Arifa; Bukhanov, Karina; Helbich, Thomas H. [Mount Sinai Hospital, University Health Network, Division of Breast Imaging, Toronto, ON (Canada); McCready, David [Princess Margaret Hospital, Department of Surgical Oncology, Toronto, ON (Canada); O' Malley, Frances [Mount Sinai Hospital, Department of Pathology, Laboratory Medicine, Toronto, ON (Canada)

    2011-03-15

    To evaluate the frequency of diagnosis of high-risk lesions at MRI-guided vacuum-assisted breast biopsy (MRgVABB) and to determine whether underestimation may be predicted. Retrospective review of the medical records of 161 patients who underwent MRgVABB was performed. The underestimation rate was defined as an upgrade of a high-risk lesion at MRgVABB to malignancy at surgery. Clinical data, MRI features of the biopsied lesions, and histological diagnosis of cases with and those without underestimation were compared. Of 161 MRgVABB, histology revealed 31 (19%) high-risk lesions. Of 26 excised high-risk lesions, 13 (50%) were upgraded to malignancy. The underestimation rates of lobular neoplasia, atypical apocrine metaplasia, atypical ductal hyperplasia, and flat epithelial atypia were 50% (4/8), 100% (5/5), 50% (3/6) and 50% (1/2) respectively. There was no underestimation in the cases of benign papilloma without atypia (0/3), and radial scar (0/2). No statistically significant differences (p > 0.1) between the cases with and those without underestimation were seen in patient age, indications for breast MRI, size of lesion on MRI, morphological and kinetic features of biopsied lesions. Imaging and clinical features cannot be used reliably to predict underestimation at MRgVABB. All high-risk lesions diagnosed at MRgVABB require surgical excision. (orig.)

  8. Gases and vacua handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 1: Gases and Vacua provides information on the many aspects of vacuum technology, from material on the quantum theoretical aspects of the complex semi-conductors used for thermionic and photo-electric emission to data on the performance of commercially available pumps, gauges, and high-vacuum materials. The handbook satisfies the need of workers using vacuum apparatuses or works on the diverse applications of high-vacuum technology in research and industry. The book is a compilation of long articles prepared by experts in vacuum technology. Sufficient theoret

  9. 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

  10. Experimental Evaluation and Comparison of Thermal Conductivity of High-Voltage Insulation Materials for Vacuum Electronic Devices

    Science.gov (United States)

    Suresh, C.; Srikrishna, P.

    2017-07-01

    Vacuum electronic devices operate with very high voltage differences between their sub-assemblies which are separated by very small distances. These devices also emit large amounts of heat that needs to be dissipated. Hence, there exists a requirement for high-voltage insulators with good thermal conductivity for voltage isolation and efficient heat dissipation. However, these voltage insulators are generally poor conductors of heat. In the present work, an effort has been made to obtain good high-voltage insulation materials with substantial improvement in their thermal conductivity. New mixtures of composites were formed by blending varying percentages (by volumes) of aluminum nitride powders with that of neat room-temperature vulcanizing (RTV) silicone elastomer compound. In this work, a thermal conductivity test setup has been devised for the quantification of the thermal conductivity of the insulators. The thermal conductivities and high-voltage isolation capabilities of various blended composites were quantified and were compared with that of neat RTV to evaluate the relative improvement.

  11. 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.)

  12. Behavior of sustained high-current arcs on molten-alloy electrodes during vacuum consumable-arc remelting

    Science.gov (United States)

    Zanner, F. J.; Bertram, L. A.

    Vacuum consumable arc remelting is a casting process carried out in a vacuum with the aim of remelting the consumable electrode in such a way that the new ingot has improved chemical and physical homogeneity. The power which causes the melting is supplied by a vacuum arc burning between the electrodes. In order to determine the furnace partitions of electrical power and current, experiments were conducted on molten faced round electrodes. The quasi-steady melt rate was determined for both horizontally opposed 15 cm dia. Ni electrodes and for vertically suspended 40 cm dia. Inconel 718 electrodes.

  13. Development of a high-speed vacuum ultraviolet (VUV) imaging system for the Experimental Advanced Superconducting Tokamak

    Science.gov (United States)

    Zhou, Fan; Ming, Tingfeng; Wang, Yumin; Wang, Zhijun; Long, Feifei; Zhuang, Qing; Li, Guoqiang; Liang, Yunfeng; Gao, Xiang

    2017-07-01

    A high-speed vacuum ultraviolet (VUV) imaging system for edge plasma studies is being developed on the Experimental Advanced Superconducting Tokamak (EAST). Its key optics is composed of an inverse type of Schwarzschild telescope made of a set of Mo/Si multilayer mirrors, a micro-channel plate (MCP) equipped with a P47 phosphor screen and a high-speed camera with CMOS sensors. In order to remove the contribution from low-energy photons, a Zr filter is installed in front of the MCP detector. With this optics, VUV photons with a wavelength of 13.5 nm, which mainly come from the line emission from intrinsic carbon (C vi: n = 4-2 transition) or the Ly-α line emission from injected Li iii on the EAST, can be selectively measured two-dimensionally with both high temporal and spatial resolutions. At present, this system is installed to view the plasma from the low field side in a horizontal port in the EAST. It has been operated routinely during the 2016 EAST experiment campaign, and the first result is shown in this work. To roughly evaluate the system performance, synthetic images are created. And it indicates that this system mainly measures the edge localized emissions by comparing the synthetic images and experimental data.

  14. Method for producing evaporation inhibiting coating for protection of silicon--germanium and silicon--molybdenum alloys at high temperatures in vacuum

    Science.gov (United States)

    Chao, P.J.

    1974-01-01

    A method is given for protecting Si--Ge and Si-- Mo alloys for use in thermocouples. The alloys are coated with silicon to inhibit the evaporation of the alloys at high tempenatures in a vacuum. Specific means and methods are provided. (5 fig) (Official Gazette)

  15. Effect of modified atmosphere and vacuum packaging conditions on selected chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber scombrus

    Directory of Open Access Journals (Sweden)

    Ivanović Jelena S.

    2016-01-01

    Full Text Available Chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber Scombrus, with emphasis on the quality and safety parameters in modified atmosphere packaging (MAP and vacuum packaging (VP, were investigated. Quality assessment of mackerel stored in MAP (40% CO2+60% N2 and VP for up to 50 days at 4±1 °C was done by the monitoring of pH value, total volatile basic nitrogen (TVB-N, thiobarbituric acid (TBA and histamine. The pH value of fish meat was significantly lower in the marinated samples. The highest concentration of TVB-N was recorded in the salted mackerel stored under VP whereas the lowest TVB-N in the marinated mackerel stored under MAP conditions. The formation of TBA increased with the time of storage and was the lowest in the marinated mackerel stored in MAP. The concentration of histamine increased during storage and its level reached over 10 mg/100 g for the salted mackerel stored under VP conditions. The marinated mackerel packed in MAP had extended shelf life at 4±1 °C compared to that packaged in VP according to physico-chemical analysis.

  16. A versatile elevated-pressure reactor combined with an ultrahigh vacuum surface setup for efficient testing of model and powder catalysts under clean gas-phase conditions

    Energy Technology Data Exchange (ETDEWEB)

    Morfin, Franck; Piccolo, Laurent [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256 CNRS and Université Lyon 1, 2 avenue Albert Einstein, F-69626 Villeurbanne (France)

    2013-09-15

    A small-volume reaction cell for catalytic or photocatalytic testing of solid materials at pressures up to 1000 Torr has been coupled to a surface-science setup used for standard sample preparation and characterization under ultrahigh vacuum (UHV). The reactor and sample holder designs allow easy sample transfer from/to the UHV chamber, and investigation of both planar and small amounts of powder catalysts under the same conditions. The sample is heated with an infrared laser beam and its temperature is measured with a compact pyrometer. Combined in a regulation loop, this system ensures fast and accurate temperature control as well as clean heating. The reaction products are automatically sampled and analyzed by mass spectrometry and/or gas chromatography (GC). Unlike previous systems, our GC apparatus does not use a recirculation loop and allows working in clean conditions at pressures as low as 1 Torr while detecting partial pressures smaller than 10{sup −4} Torr. The efficiency and versatility of the reactor are demonstrated in the study of two catalytic systems: butadiene hydrogenation on Pd(100) and CO oxidation over an AuRh/TiO{sub 2} powder catalyst.

  17. High-RRR thin-films of NB produced using energetic condensation from a coaxial, rotating vacuum ARC plasma (CEDTM)

    Science.gov (United States)

    Valderrama, Enrique Francisco; James, Colt; Krishnan, Mahadevan; Zhao, Xin; Phillips, Larry; Reece, Charles; Seo, Kang

    2012-06-01

    We have recently demonstrated unprecedentedly high values of RRR (up to 542) in thin-films of pure Nb deposited on a-plane sapphire and MgO crystal substrates. The Nb films were grown using a vacuum arc discharge struck between a reactor grade Nb cathode rod (RRR 30) and a coaxial, semi-transparent Mo mesh anode, with a heated substrate placed just outside it. The substrates were pre-heated for several hours prior to deposition at different temperatures. Low pre-heat temperatures (600°C) is correlated with better epitaxial crystal structure in both a-sapphire and MgO substrate grown films. However, the SIMS data reveal that the most important requirement for high-RRR Nb films on either substrate is the reduction of impurities in the film, especially hydrogen. The hydrogen content in the MgO grown films is 1000 times lower than in bulk Nb tested as a reference from SRF cavity grade Nb. This result has potential implications for SRF accelerators. Coating bulk Nb cavities with an MgO layer followed by our CEDTM deposited Nb films, might create superior SRF cavities that would avoid Q-slope and operate at higher peak fields. This research was supported by Department of Energy grants DE-SC0004994 and DE-FG02-08ER85162.

  18. An atomic beam source for fast loading of a magneto-optical trap under high vacuum

    DEFF Research Database (Denmark)

    McDowall, P.D.; Hilliard, Andrew; Grünzweig, T.

    2012-01-01

    We report on a directional atomic beam created using an alkali metal dispenser and a nozzle. By applying a high current (15 A) pulse to the dispenser at room temperature we can rapidly heat it to a temperature at which it starts dispensing, avoiding the need for preheating. The atomic beam produced...

  19. Matrix-assisted ionization vacuum for protein detection, fragmentation and PTM analysis on a high resolution linear ion trap-orbitrap platform.

    Science.gov (United States)

    Chen, Bingming; Lietz, Christopher B; OuYang, Chuanzi; Zhong, Xuefei; Xu, Meng; Li, Lingjun

    2016-04-15

    Matrix-assisted ionization vacuum (MAIV) is a novel ionization technique that generates multiply charged ions in vacuum without the use of laser ablation or high voltage. MAIV can be achieved in intermediate-vacuum and high-vacuum matrix-assisted laser desorption/ionization (MALDI) sources and electrospray ionization (ESI) sources without instrument modification. Herein, we adapt MAIV onto the MALDI-LTQ-Orbitrap XL platform for biomolecule analysis. As an attractive alternative to MALDI for in solution and in situ analysis of biomolecules, MAIV coupling to high resolution and accurate mass (HRAM) MS instrument has successfully expanded the mass detection range and improved the fragmentation efficiency due to the generation of multiply charged ions. Additionally, the softness of MAIV enables potential application in labile post-translational modification (PTM) analysis. In this study, proteins as large as 18.7 kDa were detected with up to 18 charges; intact peptides with labile PTM were well preserved during the ionization process and characterized MS/MS; peptides and proteins in complex tissue samples were detected and identified both in liquid extracts and in situ. Moreover, we demonstrated that this method facilitates MS/MS analysis with improved fragmentation efficiency compared to MALDI-MS/MS. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Effects of high pressure application (400 and 900 MPa) and refrigerated storage time on the oxidative stability of sliced skin vacuum packed dry-cured ham.

    Science.gov (United States)

    Clariana, Maria; Guerrero, Luis; Sárraga, Carmen; Garcia-Regueiro, José A

    2012-02-01

    The effect of high pressure processing at 400 MPa and 900 MPa on the oxidative stability of sliced and vacuum packaged commercial dry-cured ham was determined by analyzing the antioxidant enzyme activities, TBARS levels (thiobarbituric acid reactive substances), vitamin E content and physicochemical characteristics during refrigerated storage for 50 days in different light conditions. In dry-cured ham pressurized at 400 MPa color changes and sensory analyses were also assessed. The high pressure process at 900 MPa produced a decrease in superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) activities and increased vitamin E content. In contrast, pressurization at 400 MPa, increased SOD activity, and showed no effect on vitamin E content and GSHPx activity. In general the physicochemical parameters determined (fat, moisture and collagen) were unaffected by pressurization. Treatment at 400 MPa increased the instrumental color measurement of lightness (L* values, CIELAB). This level of pressure also modified the hardness, chewiness, saltiness and color intensity. These changes of the sensory attributes in dry-cured ham were significant, but small. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Reduction of Listeria innocua contamination in vacuum-packaged dry-cured Italian pork products after high hydrostatic pressure treatment

    Directory of Open Access Journals (Sweden)

    Giuseppe Merialdi

    2015-06-01

    Full Text Available The present work aims to present the results of the application of a treatment with high hydrostatic pressure (HHP on Italian fermented and dry-cured pork products. The products used in this study were portioned cured ham, portioned bacon and salami, vacuumpackaged and produced by a single processing company. Two studies were conducted on a single batch of the three products by means of an artificial contamination with Listeria innocua as a surrogate of L. monocytogenes. In the first trial a superficial contamination was obtained by immersion for 3 min in the culture broth with a concentration of approximately 9 log cfu/mL. At the end of the inoculum step, the pieces were dred at room temperature and vacuum packaged. In the second trial 50 kg of minced pork meat were contaminated before production of salami. In both cases the inoculum contained 5 strains of L. innocua. Subsequently, in both trials, 10 samples were randomly divided into two groups of 5 pieces each: i TH group, samples treated with HHP; ii group C, control samples, not subjected to any treatment. All samples were stored at refrigeration temperature at the end of HHP treatments (if applied, and analyzed for the determination of the surface (1st trial and deep (2nd trial quantitative contamination of L. innocua. pH and aW were also determined on 3 pieces of each products belonging to group C. The difference between the medians of the log cfu/cm2 or g established between controls and treated were compared using the non-parametric test (Kruskal-Wallis test with P<0.01. In all products and in both trials the level of contamination detected in treatment groups was always significantly lower than in controls (P<0.01. In particular, in vacuum-packaged ham, bacon and salami viability logarithmic viability reductions equal to -2.29, -2.54 and -2.51 were observed, respectively. This study aimed to evaluate a not-thermal treatment on Italian cured or fermented pork products. The results of

  2. Design and initial characterization of a compact, ultra high vacuum compatible, low frequency, tilt accelerometer

    Energy Technology Data Exchange (ETDEWEB)

    O’Toole, A., E-mail: amandajotoole@gmail.com, E-mail: riccardo.desalvo@gmail.com [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 405 Hilgard Ave, Los Angeles, California 90095 (United States); Peña Arellano, F. E. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Rodionov, A. V.; Kim, C. [California Institute of Technology, Pasadena, California 91125 (United States); Shaner, M.; Asadoor, M. [Mayfield Senior School, 500 Bellefontaine Street Pasadena, California 91105 (United States); Sobacchi, E. [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); Dergachev, V.; DeSalvo, R., E-mail: amandajotoole@gmail.com, E-mail: riccardo.desalvo@gmail.com [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, California 91125 (United States); Bhawal, A. [Arcadia High School, 180 Campus Drive, Arcadia, California 91007 (United States); Gong, P. [Department of Precision Instrument, Tsinghua University, Beijing 100084 (China); Lottarini, A. [Department of Computer Science, University of Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Minenkov, Y. [Sezione INFN Tor Vergata, via della Ricerca Scientfica 1, 00133 Roma (Italy); Murphy, C. [School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, Western Australia 6009 (Australia)

    2014-07-15

    A compact tilt accelerometer with high sensitivity at low frequency was designed to provide low frequency corrections for the feedback signal of the Advanced Laser Interferometer Gravitational Wave Observatory active seismic attenuation system. It has been developed using a Tungsten Carbide ceramic knife-edge hinge designed to avoid the mechanical 1/f noise believed to be intrinsic in polycrystalline metallic flexures. Design and construction details are presented; prototype data acquisition and control limitations are discussed. The instrument's characterization reported here shows that the hinge is compatible with being metal-hysteresis-free, and therefore also free of the 1/f noise generated by the dislocation Self-Organized Criticality in the metal. A tiltmeter of this kind will be effective to separate the ground tilt component from the signal of horizontal low frequency seismometers, and to correct the ill effects of microseismic tilt in advanced seismic attenuation systems.

  3. Experimental study of DC vacuum breakdown and application to high-gradient accelerating structures for CLIC

    CERN Document Server

    Shipman, Nicholas; Jones, Roger

    2016-01-01

    The compact linear collider (CLIC) is a leading candidate for the next generation high energy linear collider. As any breakdown would result in a partial or full loss of luminosity for the pulse in which it occurs, obtaining a low breakdown rate in CLIC accelerating structures is a critical requirement for the successful operation of the proposed collider. This thesis presents investigations into the breakdown phenomenon primarily in the low breakdown rate regime of interest to CLIC, performed using the CERN DC spark systems between 2011 and 2014. The design, construction and commissioning of several new pieces of hardware, as well as the development of improved techniques to measuring the inter-electrode gap distance are detailed. These hardware improvements were fundamental in enabling the exciting new experiments mentioned below, which in turn have provided significant additional insight into the phenomenon of breakdown. Experiments were performed to measure fundamental parameters of individual breakdowns...

  4. Vacuum-arc chromium-based coatings for protection of zirconium alloys from the high-temperature oxidation in air

    Energy Technology Data Exchange (ETDEWEB)

    Kuprin, A.S.; Belous, V.A.; Voyevodin, V.N., E-mail: voyev@kipt.kharkov.ua; Bryk, V.V.; Vasilenko, R.L.; Ovcharenko, V.D.; Reshetnyak, E.N.; Tolmachova, G.N.; V' yugov, P.N.

    2015-10-15

    Multilayer Cr–Zr/Cr/Cr–N coatings for protection of zirconium alloys from the high-temperature oxidation in air have been obtained by the vacuum-arc evaporation technique with application of filters for plasma cleaning from macroparticles. The effect of the coatings on the corrosion resistance of zirconium alloys at test temperatures between 660 and 1100 °C for 3600 s has been investigated. The thickness, structure, phase composition, mechanical properties of the coatings and oxide layers before and after oxidation tests were examined by scanning electron microscopy, X-ray diffraction analysis and nanoindentation technique. It is shown that the hard multilayer coating effectively protects zirconium from the oxidation in air for 1 h at test temperatures. As a result of the oxidation in the coating the CrO and Cr{sub 2}O{sub 3} oxides are formed which reduce the oxygen penetration through the coating. At maximum test temperature of 1100 °C the oxide layer thickness in the coating is about 5 μm. The tube shape remains unchanged independent of alloy type. It has been found that uncoated zirconium oxidizes rapidly throughout the temperature range under study. At 1100 °C a porous monoclinic ZrO{sub 2} oxide layer of ≥120 μm is formed that leads to the deformation of the samples, cracking and spalling of the oxide layer.

  5. Physical properties of nanometer graphene oxide films partially and fully reduced by annealing in ultra-high vacuum

    Science.gov (United States)

    Jernigan, Glenn G.; Nolde, Jill A.; Mahadik, Nadeem A.; Cleveland, Erin R.; Boercker, Janice E.; Katz, Michael B.; Robinson, Jeremy T.; Aifer, Edward H.

    2017-08-01

    The properties of reduced graphene oxide (GO) are reported from a non-chemical reduction method. Ultra-high vacuum annealing of GO films in the thickness of 1-80 nm was studied by XPS, AFM, UV-Vis-NIR, Raman, and TEM to observe the controlled removal of oxygen. We observed the loss of hydroxyl (C-OH) at low temperatures (layer spacing between the GO sheets and a concurrent decrease in the film resistance. While the Raman spectroscopy showed no change with reduction, indicating no change in the overall defect density or the general structure of the GO, the transmission spectra showed a shift in the transmission minimum from 245 nm to 260 nm, and a total decrease in transmission above 800 nm occurs as the films visibly darken. TEM indicated that there is turbostratic stacking of the graphene layers as the reduction occurs, leading us to conclude that at a certain threshold of reduction the film properties are similar to epitaxial graphene growth on the C-face of SiC, but that a reduction gone too far results in a layer spacing equivalent to graphite.

  6. Microbial thiocyanate utilization under highly alkaline conditions.

    Science.gov (United States)

    Sorokin, D Y; Tourova, T P; Lysenko, A M; Kuenen, J G

    2001-02-01

    Three kinds of alkaliphilic bacteria able to utilize thiocyanate (CNS-) at pH 10 were found in highly alkaline soda lake sediments and soda soils. The first group included obligate heterotrophs that utilized thiocyanate as a nitrogen source while growing at pH 10 with acetate as carbon and energy sources. Most of the heterotrophic strains were able to oxidize sulfide and thiosulfate to tetrathionate. The second group included obligately autotrophic sulfur-oxidizing alkaliphiles which utilized thiocyanate nitrogen during growth with thiosulfate as the energy source. Genetic analysis demonstrated that both the heterotrophic and autotrophic alkaliphiles that utilized thiocyanate as a nitrogen source were related to the previously described sulfur-oxidizing alkaliphiles belonging to the gamma subdivision of the division Proteobacteria (the Halomonas group for the heterotrophs and the genus Thioalkalivibrio for autotrophs). The third group included obligately autotrophic sulfur-oxidizing alkaliphilic bacteria able to utilize thiocyanate as a sole source of energy. These bacteria could be enriched on mineral medium with thiocyanate at pH 10. Growth with thiocyanate was usually much slower than growth with thiosulfate, although the biomass yield on thiocyanate was higher. Of the four strains isolated, the three vibrio-shaped strains were genetically closely related to the previously described sulfur-oxidizing alkaliphiles belonging to the genus Thioalkalivibrio. The rod-shaped isolate differed from the other isolates by its ability to accumulate large amounts of elemental sulfur inside its cells and by its ability to oxidize carbon disulfide. Despite its low DNA homology with and substantial phenotypic differences from the vibrio-shaped strains, this isolate also belonged to the genus Thioalkalivibrio according to a phylogenetic analysis. The heterotrophic and autotrophic alkaliphiles that grew with thiocyanate as an N source possessed a relatively high level of cyanase

  7. Vacuum fiber-fiber coupler

    Science.gov (United States)

    Heinrici, Axel; Bjelajac, Goran; Jonkers, Jeroen; Jakobs, Stefan; Olschok, Simon; Reisgen, Uwe

    2017-02-01

    Research and development carried out by the ISF Welding and Joining Institute of RWTH Aachen University has proven that combining high power laser and low vacuum atmosphere provides a welding performance and quality, which is comparable to electron beam welding. The developed welding machines are still using a beam forming which takes place outside the vacuum and the focusing laser beam has to be introduced to the vacuum via a suitable window. This inflexible design spoils much of the flexibility of modern laser welding. With the target to bring a compact, lightweight flying optics with flexible laser transport fibers into vacuum chambers, a high power fiber-fiber coupler has been adapted by II-VI HIGHYAG that includes a reliable vacuum interface. The vacuum-fiber-fiber coupler (V-FFC) is tested with up to 16 kW sustained laser power and the design is flexible in terms of a wide variety of laser fiber plug systems and vacuum flanges. All that is needed to implement the V-FFC towards an existing or planned vacuum chamber is an aperture of at least 100 mm (4 inch) diameter with any type of vacuum or pressure flange. The V-FFC has a state-of-the-art safety interface which allows for fast fiber breakage detection for both fibers (as supported by fibers) by electric wire breakage and short circuit detection. Moreover, the System also provides connectors for cooling and electric signals for the laser beam optics inside the vacuum. The V-FFC has all necessary adjustment options for coupling the laser radiation to the receiving fiber.

  8. A high-vacuum deposition system for in situ and real-time electrical characterization of organic thin-film transistors.

    Science.gov (United States)

    Quiroga, Santiago David; Shehu, Arian; Albonetti, Cristiano; Murgia, Mauro; Stoliar, Pablo; Borgatti, Francesco; Biscarini, Fabio

    2011-02-01

    We present a home-built high-vacuum system for performing organic semiconductor thin-film growth and its electrical characterization during deposition (real-time) or after deposition (in situ). Since the environment conditions remain unchanged during the deposition and electrical characterization process, a direct correlation between growth mode and electrical properties of thin film can be obtained. Deposition rate and substrate temperature can be systematically set in the range 0.1-10 ML∕min and RT-150 °C, respectively. The sample-holder configuration allows the simultaneous electrical monitoring of up to five organic thin-film transistors (OTFTs). The OTFTs parameters such as charge carrier mobility μ, threshold voltage V(TH), and the on-off ratio I(on)∕I(off) are studied as a function of the semiconductor thickness, with a submonolayer accuracy. Design, operation, and performance of the setup are detailed. As an example, the in situ and real-time electrical characterization of pentacene TFTs is reported.

  9. Vacuum properties of high quality value tuning fork in high magnetic field up to 8 Tesla and at mK temperatures

    Science.gov (United States)

    Človečko, M.; Kupka, M.; Skyba, P.; Vavrek, F.

    2014-12-01

    Tuning forks are very popular experimental tools widely applied in low and ultra low temperature physics as mechanical resonators and cantilevers in the study of quantum liquids, STM and AFM techniques, etc. As an added benefit, these forks being cooled, have very high Q-value, typically 106 and their properties seems to be magnetic field independent. We present preliminary vacuum measurements of a commercial tuning fork oscillating at frequency 32 kHz conducted in magnetic fields up to 8 T and at temperature ~ 10 mK. We found an additional weak damping of the tuning fork motion depending on magnetic field magnitude and we discuss physical nature of the observed phenomena.

  10. Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible 3He/10 T cryostat

    Science.gov (United States)

    von Allwörden, H.; Ruschmeier, K.; Köhler, A.; Eelbo, T.; Schwarz, A.; Wiesendanger, R.

    2016-07-01

    The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped 3He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where the tip and sample can be exchanged in situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).

  11. Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible (3)He/10 T cryostat.

    Science.gov (United States)

    von Allwörden, H; Ruschmeier, K; Köhler, A; Eelbo, T; Schwarz, A; Wiesendanger, R

    2016-07-01

    The design of an atomic force microscope with an all-fiber interferometric detection scheme capable of atomic resolution at about 500 mK is presented. The microscope body is connected to a small pumped (3)He reservoir with a base temperature of about 300 mK. The bakeable insert with the cooling stage can be moved from its measurement position inside the bore of a superconducting 10 T magnet into an ultra-high vacuum chamber, where the tip and sample can be exchanged in situ. Moreover, single atoms or molecules can be evaporated onto a cold substrate located inside the microscope. Two side chambers are equipped with standard surface preparation and surface analysis tools. The performance of the microscope at low temperatures is demonstrated by resolving single Co atoms on Mn/W(110) and by showing atomic resolution on NaCl(001).

  12. Vacuum production; Produccion de vacio

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, J. L. de

    2010-07-01

    Since the advent of ultra high vacuum in 1958 has been a great demand for new as means of production and to meet the process needs to be done: industry heavy, high technology and space research areas, large accelerator systems particles or nuclear fusion. In this paper we explore the modern media production: dry vacuum pumps, turbo pumps, pump status diffusion ion pumps and cryopumps. (Author)

  13. Household vacuum cleaners vs. the high-volume surface sampler for collection of carpet dust samples in epidemiologic studies of children.

    Science.gov (United States)

    Colt, Joanne S; Gunier, Robert B; Metayer, Catherine; Nishioka, Marcia G; Bell, Erin M; Reynolds, Peggy; Buffler, Patricia A; Ward, Mary H

    2008-02-21

    Levels of pesticides and other compounds in carpet dust can be useful indicators of exposure in epidemiologic studies, particularly for young children who are in frequent contact with carpets. The high-volume surface sampler (HVS3) is often used to collect dust samples in the room in which the child had spent the most time. This method can be expensive and cumbersome, and it has been suggested that an easier method would be to remove dust that had already been collected with the household vacuum cleaner. However, the household vacuum integrates exposures over multiple rooms, some of which are not relevant to the child's exposure, and differences in vacuuming equipment and practices could affect the chemical concentration data. Here, we compare levels of pesticides and other compounds in dust from household vacuums to that collected using the HVS3. Both methods were used in 45 homes in California. HVS3 samples were collected in one room, while the household vacuum had typically been used throughout the home. The samples were analyzed for 64 organic compounds, including pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls (PCBs), using GC/MS in multiple ion monitoring mode; and for nine metals using conventional microwave-assisted acid digestion combined with ICP/MS. The methods agreed in detecting the presence of the compounds 77% to 100% of the time (median 95%). For compounds with less than 100% agreement, neither method was consistently more sensitive than the other. Median concentrations were similar for most analytes, and Spearman correlation coefficients were 0.60 or higher except for allethrin (0.15) and malathion (0.24), which were detected infrequently, and benzo(k)fluoranthene (0.55), benzo(a)pyrene (0.55), PCB 105 (0.54), PCB 118 (0.54), and PCB 138 (0.58). Assuming that the HVS3 method is the "gold standard," the extent to which the household vacuum cleaner method yields relative risk estimates closer to unity by increasing random

  14. Household vacuum cleaners vs. the high-volume surface sampler for collection of carpet dust samples in epidemiologic studies of children

    Directory of Open Access Journals (Sweden)

    Buffler Patricia A

    2008-02-01

    Full Text Available Abstract Background Levels of pesticides and other compounds in carpet dust can be useful indicators of exposure in epidemiologic studies, particularly for young children who are in frequent contact with carpets. The high-volume surface sampler (HVS3 is often used to collect dust samples in the room in which the child had spent the most time. This method can be expensive and cumbersome, and it has been suggested that an easier method would be to remove dust that had already been collected with the household vacuum cleaner. However, the household vacuum integrates exposures over multiple rooms, some of which are not relevant to the child's exposure, and differences in vacuuming equipment and practices could affect the chemical concentration data. Here, we compare levels of pesticides and other compounds in dust from household vacuums to that collected using the HVS3. Methods Both methods were used in 45 homes in California. HVS3 samples were collected in one room, while the household vacuum had typically been used throughout the home. The samples were analyzed for 64 organic compounds, including pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls (PCBs, using GC/MS in multiple ion monitoring mode; and for nine metals using conventional microwave-assisted acid digestion combined with ICP/MS. Results The methods agreed in detecting the presence of the compounds 77% to 100% of the time (median 95%. For compounds with less than 100% agreement, neither method was consistently more sensitive than the other. Median concentrations were similar for most analytes, and Spearman correlation coefficients were 0.60 or higher except for allethrin (0.15 and malathion (0.24, which were detected infrequently, and benzo(kfluoranthene (0.55, benzo(apyrene (0.55, PCB 105 (0.54, PCB 118 (0.54, and PCB 138 (0.58. Assuming that the HVS3 method is the "gold standard," the extent to which the household vacuum cleaner method yields relative risk

  15. FOREWORD: The 4th CCM International Conference on Pressure Metrology from Ultra-High Vacuum to Very High Pressures (10-9 Pa to 109 Pa)

    Science.gov (United States)

    Legras, Jean-Claude; Jousten, Karl; Severn, Ian

    2005-12-01

    The fourth CCM (Consultative Committee for Mass and related quantities) International Conference on Pressure Metrology from Ultra-High Vacuum to Very High Pressures (10-9 Pa to 109 Pa) was held at the Institute of Physics in London from 19-21 April 2005. The event, which was organized by the Low, Medium and High Pressure working groups of the CCM, was attended by in excess of one hundred participants with representatives from five continents and every regional metrology organization. The purpose of this conference is to review all the work that is devoted to the highest quality of pressure measurement by primary standards as well as the dissemination of the pressure scale. A total of 52 papers were presented orally, and 26 as posters, in sessions that covered the following topics: Latest scientific advances in pressure and vacuum metrology Innovative transfer standards, advanced sensors and new instrument development Primary (top-level) measurement standards International and regional key comparisons New approaches to calibration It is interesting the note that since the third conference in 1999 the pressure range covered has increased by two orders of magnitude to 109 Pa, to take into account more exacting scientific and industrial demands for traceable vacuum measurement. A further feature of the conference was the increased range of instrumentation and techniques used in the realization and potential realization of pressure standards. Seton Bennett, Director of International Metrology at the National Physical Laboratory, opened the conference and Andrew Wallard, Director of the Bureau International des Poids et Mesures (BIPM), gave the keynote address which described the implementation of the mutual recognition arrangement and the resulting removal of metrological barriers to international trade. Many experts have contributed significant amounts of their time to organize the event and to review the submitted papers. Thanks are due to all of these people

  16. 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...

  17. Development of a control system for compression and expansion cycles of critical valve for high vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Jyoti, E-mail: jagarwal@ipr.res.in; Sharma, H.; Patel, Haresh; Gangradey, R.; Lambade, Vrushabh

    2016-11-15

    Highlights: • Control system with feedback loop of pressure gauge is developed for measuring the life cycle of vacuum isolation valve. • GUI based software developed for easy use and handling of control system. • Control system tested with an experiment showcasing the capability of the control system. • Control system can operate valve based on pressure inside the chamber, which helps to know the degradation of sealing capabilities of valve. • Control system can monitor the total closing and opening time of valve, cycles and pressure inside the vessel. - Abstract: A control system with feedback loop is designed, developed and tested to monitor the life cycles of the axial valve and bellows used in vacuum valves. The control system monitors number of compression cycles of any bellow or closing and opening cycle of a valve. It also interfaces vacuum gauges or pressure gauges to get pressure values inside the system. To find life cycle of valve, the developed control and monitoring system is integrated with an axial valve experimental test set up. In this system, feedback from the vacuum gauge attached to valve enclosure, is given and the life cycle test is automated. This paper describes the control and monitoring system in details and briefs the experiment carried out for valve life cycle. The same system can be used for life cycle estimate for bellows. A suitable GUI is also developed to control the function of the components and resister the number of cycles.

  18. Direct comparison of highly efficient solution- and vacuum-processed organic solar cells based on merocyanine dyes

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, Nils M.; Steinmann, Vera; Hertel, Dirk; Meerholz, Klaus [Department fuer Chemie, Universitaet Koeln, Luxemburger Strasse 116, 50939 Koeln (Germany); Buerckstuemmer, Hannah; Wuerthner, Frank [Institut fuer Organische Chemie and Roentgen Research Center for Complex Material Systems, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Hwang, Jaehyung [BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen (Germany)

    2010-10-01

    Identically configured bulk heterojunction organic solar cells based on merocyanine dye donor and fullerene acceptor compounds are manufactured either from solution or by vacuum deposition, to enable a direct comparison. Whereas the former approach is more suitable for screening purposes, the latter approach affords higher short-circuit current density and power conversion efficiency. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  19. Preparation and characterization of pixelated phosphor screens for high-resolution linear imaging in the vacuum ultraviolet and x-ray ranges

    Science.gov (United States)

    Rodríguez-Barquero, L.; Zurro, B.; Martin, P.; McCarthy, K. J.; Baciero, A.

    2004-10-01

    Indirect digital imaging sensors employ tailored phosphors screens to convert incident x-ray or vacuum-ultraviolet (VUV) photons to visible light quanta A convenient method to prepare pixelated phosphor screens that can be easily tailored in thickness, type, and spatial resolution is presented. The characterization and evaluation of these screens in the laboratory is addressed and their application to high-resolution VUV and x-ray cameras is discussed.

  20. The properties of ZnO films obtained by high-frequency magnetron deposition with subsequent vacuum annealing and plasma treatment

    Science.gov (United States)

    Redka, D. N.; Elanskaia, K. G.; Bakhchova, L. D.

    2017-07-01

    The method of high-frequency magnetron sputtering allows to obtain thin films of zinc oxide with nanostructured surface morphology and, consequently, with unique optical characteristics. Such coating can provide an increase in the number of particles penetrating the photovoltaic structure and the length of their optical path. Vacuum-plasma processing of ZnO films allows to change the morphology of their surface, and annealing largely influences the optical transmission.

  1. A modified ‘NanoSuit®’ preserves wet samples in high vacuum: direct observations on cells and tissues in field-emission scanning electron microscopy

    Science.gov (United States)

    Takaku, Yasuharu; Suzuki, Hiroshi; Kawasaki, Hideya; Ohta, Isao; Ishii, Daisuke; Hirakawa, Satoshi; Tsutsui, Takami; Matsumoto, Haruko; Takehara, Sayuri; Nakane, Chinatsu; Sakaida, Kana; Suzuki, Chiaki; Muranaka, Yoshinori; Kikuchi, Hirotoshi; Konno, Hiroyuki; Shimomura, Masatsugu

    2017-01-01

    Although field-emission scanning electron microscopy (FE-SEM) has proven very useful in biomedical research, the high vacuum required (10−3 to 10−7 Pa) precludes direct observations of living cells and tissues at high resolution and often produces unwanted structural changes. We have previously described a method that allows the investigator to keep a variety of insect larvae alive in the high vacuum environment of the electron microscope by encasing the organisms in a thin, vacuum-proof suit, the ‘NanoSuit®'. However, it was impossible to protect wet tissues freshly excised from intact organisms or cultured cells. Here we describe an improved ‘NanoSuit' technique to overcome this limitation. We protected the specimens with a surface shield enhancer (SSE) solution that consists of glycerine and electrolytes and found that the fine structure of the SSE-treated specimens is superior to that of conventionally prepared specimens. The SSE-based NanoSuit affords a much stronger barrier to gas and/or liquid loss than the previous NanoSuit did and, since it allows more detailed images, it could significantly help to elucidate the ‘real' organization of cells and their functions. PMID:28405375

  2. A modified 'NanoSuit®' preserves wet samples in high vacuum: direct observations on cells and tissues in field-emission scanning electron microscopy.

    Science.gov (United States)

    Takaku, Yasuharu; Suzuki, Hiroshi; Kawasaki, Hideya; Ohta, Isao; Ishii, Daisuke; Hirakawa, Satoshi; Tsutsui, Takami; Matsumoto, Haruko; Takehara, Sayuri; Nakane, Chinatsu; Sakaida, Kana; Suzuki, Chiaki; Muranaka, Yoshinori; Kikuchi, Hirotoshi; Konno, Hiroyuki; Shimomura, Masatsugu; Hariyama, Takahiko

    2017-03-01

    Although field-emission scanning electron microscopy (FE-SEM) has proven very useful in biomedical research, the high vacuum required (10-3 to 10-7 Pa) precludes direct observations of living cells and tissues at high resolution and often produces unwanted structural changes. We have previously described a method that allows the investigator to keep a variety of insect larvae alive in the high vacuum environment of the electron microscope by encasing the organisms in a thin, vacuum-proof suit, the 'NanoSuit®'. However, it was impossible to protect wet tissues freshly excised from intact organisms or cultured cells. Here we describe an improved 'NanoSuit' technique to overcome this limitation. We protected the specimens with a surface shield enhancer (SSE) solution that consists of glycerine and electrolytes and found that the fine structure of the SSE-treated specimens is superior to that of conventionally prepared specimens. The SSE-based NanoSuit affords a much stronger barrier to gas and/or liquid loss than the previous NanoSuit did and, since it allows more detailed images, it could significantly help to elucidate the 'real' organization of cells and their functions.

  3. Historical evolution toward achieving ultrahigh vacuum in JEOL electron microscopes

    CERN Document Server

    Yoshimura, Nagamitsu

    2014-01-01

    This book describes the developmental history of the vacuum system of the transmission electron microscope (TEM) at the Japan Electron Optics Laboratory (JEOL) from its inception to its use in today’s high-technology microscopes. The author and his colleagues were engaged in developing vacuum technology for electron microscopes (JEM series) at JEOL for many years. This volume presents a summary and explanation of their work and the technology that makes possible a clean ultrahigh vacuum. The typical users of the TEM are top-level researchers working at the frontiers of new materials or with new biological specimens. They often use the TEM under extremely severe conditions, with problems sometimes occurring in the vacuum system of the microscopes. JEOL engineers then must work as quickly as possible to improve the vacuum evacuation system so as to prevent the recurrence of such problems. Among the wealth of explanatory material in this book are examples of users’ reports of problems in the vacuum system of...

  4. Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

    DEFF Research Database (Denmark)

    Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.

    2017-01-01

    We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...

  5. Development of Subischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

    Science.gov (United States)

    2016-12-01

    limb amputation. Healthcare Quarterly 440 2008;11:117-121. 441 53. Kahle JT, Highsmith MJ. Transfemoral sockets with vacuum-assisted suspension442...in-patients following major lower-limb amputation. Healthcare Quarterly 302 2008;11:117-121. 303 2953. Kahle JT, Highsmith MJ. Transfemoral sockets...velocity is then the speed at which the generator spins . The generated voltage is then calculated by the equation: = "# × # Here, Kg is the

  6. Edge conduction in vacuum glazing

    Energy Technology Data Exchange (ETDEWEB)

    Simko, T.M.; Collins, R.E. [Sydney Univ., NSW (Australia). Dept. of Applied Physics; Beck, F.A.; Arasteh, D. [Lawrence Berkeley Lab., CA (United States)

    1995-03-01

    Vacuum glazing is a form of low-conductance double glazing using in internal vacuum between the two glass sheets to eliminate heat transport by gas conduction and convection. An array of small support pillars separates the sheets; fused solder glass forms the edge seal. Heat transfer through the glazing occurs by radiation across the vacuum gap, conduction through the support pillars, and conduction through the bonded edge seal. Edge conduction is problematic because it affects stresses in the edge region, leading to possible failure of the glazing; in addition, excessive heat transfer because of thermal bridging in the edge region can lower overall window thermal performance and decrease resistance to condensation. Infrared thermography was used to analyze the thermal performance of prototype vacuum glazings, and, for comparison, atmospheric pressure superwindows. Research focused on mitigating the edge effects of vacuum glazings through the use of insulating trim, recessed edges, and framing materials. Experimentally validated finite-element and finite-difference modeling tools were used for thermal analysis of prototype vacuum glazing units and complete windows. Experimental measurements of edge conduction using infrared imaging were found to be in good agreement with finite-element modeling results for a given set of conditions. Finite-element modeling validates an analytic model developed for edge conduction.

  7. [Endoscopic vacuum-assisted closure].

    Science.gov (United States)

    Wedemeyer, J; Lankisch, T

    2013-03-01

    Anastomotic leakage in the upper and lower intestinal tract is associated with high morbidity and mortality. Within the last 10 years endoscopic treatment options have been accepted as sufficient treatment option of these surgical complications. Endoscopic vacuum assisted closure (E-VAC) is a new innovative endoscopic therapeutic option in this field. E-VAC transfers the positive effects of vacuum assisted closure (VAC) on infected cutaneous wounds to infected cavities that can only be reached endoscopically. A sponge connected to a drainage tube is endoscopically placed in the leakage and a continuous vacuum is applied. Sponge and vacuum allow removal of infected fluids and promote granulation of the leakage. This results in clean wound grounds and finally allows wound closure. Meanwhile the method was also successfully used in the treatment of necrotic pancreatitis.

  8. Toward high-performance vacuum-deposited organic light-emitting diodes: novel sublimable cationic iridium(III) complexes with yellow and orange electroluminescence.

    Science.gov (United States)

    Duan, Lian; Ma, Dongxin; Zhang, Chen; Liu, Ruihuan; Qiu, Yong

    2018-01-28

    Great advances in the development of efficient luminescent materials are the driving force behind organic light-emitting diodes (OLEDs). Sublimable ionic transition metal complexes (iTMCs) have emerged as a large family of new emissive dopants applied for vacuum-deposited OLEDs, while the achievement of excellent performance remains arduous. A series of novel sublimable cationic iridium(III) complexes is designed and synthesized, containing an imidazole-type ancillary ligand and tetraphenylborate-type negative counter-ions with large steric hindrance and well-dispersed charges. The photophysical properties, electrochemical behaviors and thermal stability are fully investigated and discussed, then demonstrated by theoretical calculations. Yellow- and orange-emitting OLEDs thereof are fabricated by vacuum evaporation deposition, realizing high external quantum efficiency up to 11 %, maximum brightness over 27.3×103 cd/m2 and low turn-on voltages below 2.4 V, among the best results of analogous phosphorescent OLEDs based on iTMCs. This work indicates the promising applications of sublimable iTMCs in state-of-the-art vacuum-deposited optoelectronic devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. High risk of fistula formation in vacuum-assisted closure therapy in patients with open abdomen due to secondary peritonitis-a retrospective analysis.

    Science.gov (United States)

    Mintziras, Ioannis; Miligkos, Michael; Bartsch, Detlef Klaus

    2016-08-01

    The aim of this study was to evaluate the efficacy of vacuum-assisted closure therapy in patients with open abdomen due to secondary peritonitis and to identify possible risk factors of fistula formation. The hospital OPS-database (time period 2005-2014) was searched to identify patients treated with an open abdomen due to secondary peritonitis, who underwent vacuum-assisted closure therapy. Medical records were retrospectively analyzed for patients' characteristics, cause of peritonitis, duration of vacuum therapy, number of relaparotomies, fascial closure rates, and risk factors of fistula formation. Forty-three patients (19 male, 24 female) with a median age of 65 years (range 24-90 years) were identified. The major cause of secondary peritonitis was anastomotic leakage after intestinal anastomosis or bowel perforation, the median APACHE II score was 11. Median duration of VAC treatment was 12 days (range 3-88 days). Twenty of 43 (47 %) patients died from septic complications. Delayed fascial closure was obtained by suturing in 20 of 43 patients (47 %). Overall 16 of 43 (37 %) patients developed enteroatmospheric fistulas. Re-explorations after starting VAC treatment and duration of VAC therapy were significantly associated with the occurrence of enteroatmospheric fistulas (p peritonitis results in a relatively low fascial closure rate and a high risk of fistula formation.

  10. Design and performance of an ultra-high vacuum scanning tunneling microscope operating at dilution refrigerator temperatures and high magnetic fields

    Science.gov (United States)

    Misra, S.; Zhou, B. B.; Drozdov, I. K.; Seo, J.; Urban, L.; Gyenis, A.; Kingsley, S. C. J.; Jones, H.; Yazdani, A.

    2013-10-01

    We describe the construction and performance of a scanning tunneling microscope capable of taking maps of the tunneling density of states with sub-atomic spatial resolution at dilution refrigerator temperatures and high (14 T) magnetic fields. The fully ultra-high vacuum system features visual access to a two-sample microscope stage at the end of a bottom-loading dilution refrigerator, which facilitates the transfer of in situ prepared tips and samples. The two-sample stage enables location of the best area of the sample under study and extends the experiment lifetime. The successful thermal anchoring of the microscope, described in detail, is confirmed through a base temperature reading of 20 mK, along with a measured electron temperature of 250 mK. Atomically resolved images, along with complementary vibration measurements, are presented to confirm the effectiveness of the vibration isolation scheme in this instrument. Finally, we demonstrate that the microscope is capable of the same level of performance as typical machines with more modest refrigeration by measuring spectroscopic maps at base temperature both at zero field and in an applied magnetic field.

  11. Ultra high vacuum high precision low background setup with temperature control for thermal desorption mass spectroscopy (TDA-MS) of hydrogen in metals.

    Science.gov (United States)

    Merzlikin, Sergiy V; Borodin, S; Vogel, D; Rohwerder, M

    2015-05-01

    In this work, a newly developed UHV-based high precision low background setup for hydrogen thermal desorption analysis (TDA) of metallic samples is presented. Using an infrared heating with a low thermal capacity enables a precise control of the temperature and rapid cool down of the measurement chamber. This novel TDA-set up is superior in sensitivity to almost every standard hydrogen analyzer available commercially due to the special design of the measurement chamber, resulting in a very low hydrogen background. No effects of background drift characteristic as for carrier gas based TDA instruments were observed, ensuring linearity and reproducibility of the analysis. This setup will prove to be valuable for detailed investigations of hydrogen trapping sites in steels and other alloys. With a determined limit of detection of 5.9×10(-3)µg g(-1) hydrogen the developed instrument is able to determine extremely low hydrogen amounts even at very low hydrogen desorption rates. This work clearly demonstrates the great potential of ultra-high vacuum thermal desorption mass spectroscopy instrumentation. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. High-vacuum optical platform for cryo-CLEM (HOPE): A new solution for non-integrated multiscale correlative light and electron microscopy.

    Science.gov (United States)

    Li, Shuoguo; Ji, Gang; Shi, Yang; Klausen, Lasse Hyldgaard; Niu, Tongxin; Wang, Shengliu; Huang, Xiaojun; Ding, Wei; Zhang, Xiang; Dong, Mingdong; Xu, Wei; Sun, Fei

    2018-01-01

    Cryo-correlative light and electron microscopy (cryo-CLEM) offers a unique way to analyze the high-resolution structural information of cryo-vitrified specimen by cryo-electron microscopy (cryo-EM) with the guide of the search for unique events by cryo-fluorescence microscopy (cryo-FM). To achieve cryo-FM, a trade-off must be made between the temperature and performance of objective lens. The temperature of specimen should be kept below devitrification while the distance between the objective lens and specimen should be short enough for high resolution imaging. Although special objective lens was designed in many current cryo-FM approaches, the unavoided frosting and ice contamination are still affecting the efficiency of cryo-CLEM. In addition, the correlation accuracy between cryo-FM and cryo-EM would be reduced during the current specimen transfer procedure. Here, we report an improved cryo-CLEM technique (high-vacuum optical platform for cryo-CLEM, HOPE) based on a high-vacuum optical stage and a commercial cryo-EM holder. The HOPE stage comprises of a special adapter to suit the cryo-EM holder and a high-vacuum chamber with an anti-contamination system. It provides a clean and enduring environment for cryo specimen, while the normal dry objective lens in room temperature can be used via the optical windows. The 'touch-free' specimen transfer via cryo-EM holder allows least specimen deformation and thus maximizes the correlation accuracy between cryo-FM and cryo-EM. Besides, we developed a software to perform semi-automatic cryo-EM acquisition of the target region localized by cryo-FM. Our work provides a new solution for cryo-CLEM and can be adapted for different commercial fluorescence microscope and electron microscope. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Technical specification for vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Khaw, J. (ed.)

    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/sup -5/ to 10/sup -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. (LEW)

  14. Effect of chitosan treatments on quality parameters of fresh refrigerated swordfish (Xiphias gladius) steaks stored in air and under vacuum conditions.

    Science.gov (United States)

    Tsiligianni, Maria; Papavergou, Eikaterini; Soultos, Nikolaos; Magra, Taxiarhoula; Savvaidis, Ioannis N

    2012-10-01

    The present study examined the effect of chitosan (1.0% w/v) in combination with packaging on the shelf-life of fresh swordfish steaks. Treatments included the following: A (untreated, control samples stored in air), A-CH (treated with chitosan 1.0% w/v, stored in air), VP (untreated, stored under vacuum packaging) and VP-CH (treated with chitosan, stored under vacuum packaging). VP-CH significantly affected Total Viable Counts (TVC), Pseudomonas spp., H(2)S-producing bacteria (including Shewanella putrefaciens), lactic acid bacteria and Enterobacteriaceae. Production of TMA-N and TVB-N for A-CH, VP and VP-CH swordfish samples was significantly lower than for control (A) samples at day 8 of storage. Histamine formation for all treatments was low. A-CH and VP-CH resulted in significantly lower levels of putrescine, cadaverine and tyramine (day 8) as compared to A and VP swordfish samples. Results of this study indicate that the shelf-life of swordfish steaks can be extended using, either aerobic or vacuum packaging and in combination with chitosan, by approximately 4 (A-CH), 8 (VP) and 12 (VP-CH) days. Swordfish steaks treated with chitosan and stored under VP were sensorially acceptable up to 17days. The presence of chitosan (A-CH and VP-CH) did not negatively influence the taste of cooked swordfish. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Measurement of partial pressures in vacuum technology and vacuum physics

    Science.gov (United States)

    Huber, W. K.

    1986-01-01

    It is pointed out that the measurement of gaseous pressures of less than 0.0001 torr is based on the ionization of gas atoms and molecules due to collisions with electrons. The particle density is determined in place of the pressure. The ionization cross sections for molecules of various gases are discussed. It is found that the true pressure in a vacuum system cannot be determined with certainty if it is unknown which gas is present. Effects of partial pressure determination on the condition of the vacuum system are discussed together with ion sources, systems of separation, and ion detection.

  16. Vacuum alignment with and without elementary scalars

    DEFF Research Database (Denmark)

    Alanne, Tommi; Gertov, Helene; Meroni, Aurora

    2016-01-01

    We systematically elucidate differences and similarities of the vacuum alignment issue in composite and renormalizable elementary extensions of the Standard Model featuring a pseudo-Goldstone Higgs. We also provide general conditions for the stability of the vacuum in the elementary framework...

  17. Surface Emitting, High Efficiency Near-Vacuum Ultraviolet Light Source with Aluminum Nitride Nanowires Monolithically Grown on Silicon.

    Science.gov (United States)

    Zhao, S; Djavid, M; Mi, Z

    2015-10-14

    To date, it has remained challenging to realize electrically injected light sources in the vacuum ultraviolet wavelength range (∼200 nm or shorter), which are important for a broad range of applications, including sensing, surface treatment, and photochemical analysis. In this Letter, we have demonstrated such a light source with molecular beam epitaxially grown aluminum nitride (AlN) nanowires on low cost, large area Si substrate. Detailed angle dependent electroluminescence studies suggest that, albeit the light is TM polarized, the dominant light emission direction is from the nanowire top surface, that is, along the c axis, due to the strong light scattering effect. Such an efficient surface emitting device was not previously possible using conventional c-plane AlN planar structures. The AlN nanowire LEDs exhibit an extremely large electrical efficiency (>85%), which is nearly ten times higher than the previously reported AlN planar devices. Our detailed studies further suggest that the performance of AlN nanowire LEDs is predominantly limited by electron overflow. This study provides important insight on the fundamental emission characteristics of AlN nanowire LEDs and also offers a viable path to realize an efficient surface emitting near-vacuum ultraviolet light source through direct electrical injection.

  18. Time-resolved photoelectron spectroscopy of polyatomic molecules using 42-nm vacuum ultraviolet laser based on high harmonics generation

    Science.gov (United States)

    Nishitani, Junichi; West, Christopher W.; Higashimura, Chika; Suzuki, Toshinori

    2017-09-01

    Time-resolved photoelectron spectroscopy (TRPES) of gaseous polyatomic molecules using 266-nm (4.7 eV) pump and 42-nm (29.5 eV) probe pulses is presented. A 1-kHz Ti:sapphire laser with a 35 fs pulse duration is employed to generate high harmonics in Kr gas, and the 19th harmonic (42-nm) was selected using two SiC/Mg mirrors. Clear observation of the ultrafast electronic dephasing in pyrazine and photoisomerization of 1,3-cyclohexadiene demonstrates the feasibility of TRPES with the UV pump and VUV probe pulses under weak excitation conditions in the perturbation regime.

  19. Relationship of porcelain insulator temperature and flashover voltage measurement procedure in vacuum

    Science.gov (United States)

    Wańkowicz, J.

    In this paper the existence of a connection between a conditioning procedure and the solid insulator temperature changes in a vacuum is shown. The increase of an insulator temperature and consolidation of the other working-temperature in the system insulator-electrodes, is a predominant feature for the high voltage measurements performed on dimensionally small insulators in a vacuum. It was found that numerous surface breakdowns influence the insulator surface strength due to its temperature changes.

  20. RFQ Vacuum brazing at CERN

    CERN Document Server

    Mathot, S

    2008-01-01

    The aim of this paper is to describe the vacuum brazing procedure used at CERN for the brazing of Radio Frequency Quadrupole (RFQ). The RFQ is made of high precision machined OFE copper pieces assembled together. Vacuum brazing is one of the most promising techniques used to join the individual components leading to vacuum tightness and high precision alignment. The RFQ modules brazed at CERN are made of four 100 or 120 cm long vanes (two major and two minor vanes). Our brazing procedure consists of two steps. The first step involves the brazing of the four vanes in a horizontal position. The second step consists of brazing the vacuum stainless steel flanges to the copper structure in a vertical position. The paper describes the problems encountered with the alignment and the vacuum tightness. The difficulties related to the stress relaxation of the machined copper pieces during the brazing heat treatment are discussed. In addition, the solutions developed to improve the alignment of the brazed RFQ’s are...

  1. The potential of the lichen symbiosis to cope with extreme conditions of outer space - I. Influence of UV radiation and space vacuum on the vitality of lichen symbiosis and germination capacity

    Science.gov (United States)

    de Vera, J.-P.; Horneck, G.; Rettberg, P.; Ott, S.

    2002-10-01

    The lichen symbiotic organisms Fulgensia bracteata and Xanthoria elegans as well as their isolated photobionts and mycobionts were exposed to conditions simulating the extreme parameters of outer space in order to assess their limits of survival, e.g. during a potential interplanetary transfer or on the surface of an extraterrestrial body. Using the space simulation facilities at DLR, the test parameters under investigation were vacuum (10[minus sign]3 Pa) and ultraviolet (UV) radiation at wavelength ranges from vacuum-UV to UV-A, applied separately or in combination. An analysis of vitality was made using confocal laser scanning microscopy and LIVE/DEAD staining using FUN I or SYTOX green. Intact lichens were extremely resistant to vacuum exposure as well as to UV radiation up to doses of about 160 kJ m[minus sign]2 (200<[lambda]<400 nm). Removal of the upper-cortex structure significantly increased the sensitivity of the lichens to the space parameters: already a relatively short treatment of about 5 h and a UV dose of about 50 kJ m[minus sign]2 reduced the vitality rate to nearly 50%; however, the dose effect curves levelled off and continued treatment did not reduce the vitality further. Similar survival curves levelling off at higher UV doses were observed for the isolated photobionts; however, in the latter cases, the saturation occurred at five times lower doses (full UV spectrum). Also spores of the mycobionts showed a remarkable UV (254 nm) resistance up to doses of about 3 kJ m[minus sign]2. The data suggest that the symbiotic features peculiar to lichens allow them to cope with the extreme conditions of outer space or even with Martian surface conditions provided suitable niche habitats are available to serve as refuges and complementary endogenous or exogenous protection mechanisms are established.

  2. A new cluster-ion-beam source for secondary ion mass spectrometry (SIMS) using the electrospray of a pure ionic liquid under high vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Yukio, E-mail: yukio-fujiwara@aist.go.j [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba-shi, Ibaraki-ken 305-8568 (Japan); Saito, Naoaki; Nonaka, Hidehiko; Nakanaga, Taisuke; Ichimura, Shingo [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba-shi, Ibaraki-ken 305-8568 (Japan)

    2010-06-15

    Electrospray characteristics were studied using a pure room-temperature molten salt (i.e., an ionic liquid) at pressures around 10{sup -5} Pa as well as at atmospheric pressure. The ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide was tested, which has negligible vapor pressure and high conductivity. During electrospray, the ionic liquid was introduced at a constant flow rate into a stainless-steel capillary (i.d. 30 {mu}m). It was demonstrated that stable electrosprayed currents exceeding {+-}1 {mu}{Alpha} were continuously produced in both positive and negative modes. The electrosprayed currents in a high vacuum were twice those at atmospheric pressure. It was found that gas pressure rose slightly with increasing electrosprayed currents. Residual gas analysis revealed that gas component at negative mode was different from that at positive mode. Experimental results indicate that vacuum electrospray of pure ionic liquids is applicable to a massive-cluster beam source for SIMS.

  3. 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

  4. Vacuum arc localization in CLIC prototype radio frequency accelerating structures

    CERN Document Server

    AUTHOR|(CDS)2091976; Koivunen, Visa

    2016-04-04

    A future linear collider capable of reaching TeV collision energies should support accelerating gradients beyond 100 MV/m. At such high fields, the occurrence of vacuum arcs have to be mitigated through conditioning, during which an accelerating structure’s resilience against breakdowns is slowly increased through repeated radio frequency pulsing. Conditioning is very time and resource consuming, which is why developing more efficient procedures is desirable. At CERN, conditioning related research is conducted at the CLIC high-power X-band test stands. Breakdown localization is an important diagnostic tool of accelerating structure tests. Abnormal position distributions highlight issues in structure design, manufacturing or operation and may consequently help improve these processes. Additionally, positioning can provide insight into the physics of vacuum arcs. In this work, two established positioning methods based on the time-difference-ofarrival of radio frequency waves are extended. The first method i...

  5. Of vacuum and gas

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    A new LHCb programme is delving into uncharted waters for the LHC: exploring how protons interact with noble gases inside the machine pipe. While, at first glance, it may sound risky for the overall quality of the vacuum in the machine, the procedure is safe and potentially very rich in rewards. The results could uncover the high-energy helium-proton cross-section (with all the implications thereof), explore new boundaries of the quark-gluon plasma and much more.   As the beam passes through LHCb, interactions with neon gas allow the experiment to measure the full beam profile. In this diagram, beam 1 (blue) and beam 2 (red) are measured by the surrounding VELO detector. It all begins with luminosity. In 2011, LHCb set out to further improve its notoriously precise measurements of the beam profile, using the so-called Beam-Gas Imaging (BGI) method. BGI does exactly what it says on the tin: a small amount of gas is inserted into the vacuum, increasing the rate of collisions around the interaction ...

  6. Vacuum Cleaner Fan Being Improved

    Science.gov (United States)

    Tweedt, Daniel L.

    1997-01-01

    As part of the technology utilization program at the NASA Lewis Research Center, efforts are underway to transfer aerospace technologies to new areas of practical application. One such effort involves using advanced computational fluid dynamics (CFD) codes for turbomachinery to analyze the internal fluid dynamics of low-speed fans and blowers. This year, the Kirby Company in Cleveland, Ohio, approached NASA with a request for technologies that could help them improve their vacuum cleaners. Of particular interest to Kirby is the high-frequency blade-passing noise generation of their vacuum cleaner fan at low airflow rates.

  7. Influence of vacuum-ageing duration of whole beef on retail shelf life of steaks packaged with oregano (Origanum vulgare L.) active film under high O2.

    Science.gov (United States)

    Djenane, Djamel; Beltrán, José Antonio; Camo, Javier; Roncalés, Pedro

    2016-12-01

    Beef Longissimus lumborum (LL) was no aged (LL0), aged for 7 days (LL7) and 14 days (LL14) under vacuum at 1 ± 1 °C. The obtained beefsteaks were packaged in high oxygen (Hi-O2) with active packaging (AP) during 13-21 days at 1 ± 1 °C. Redness (CIE a* values), metmyoglobin percentage (MetMb%), total flora (PCA), thiobarbituric acid-reactive substances (TBA-RS), instrumental tenderness (Warner-Bratzler shear force: WBSF), and sensory analyses were performed. The various variables differed amongst the ageing times and packaging systems (AP vs. control). Three and ten additional days of retail shelf life were observed for steaks from LL7 and LL14, respectively. AP increased efficiently the retail shelf life of beefsteaks, but did not affect meat tenderness. The extended ageing from 7 to 14 days also induced higher tenderness in beefsteaks and did not show any affect negative effect on other quality parameters. Innovative technology referring to ageing under vacuum combined with Hi-O2 MA/AP would be desirable for beefsteaks during display and constituted a good alternative for meat supermarkets.

  8. In vitro pressure manifolding distribution evaluation of ABThera™ Active Abdominal Therapy System, V.A.C.® Abdominal Dressing System, and Barker’s vacuum packing technique conducted under dynamic conditions

    Directory of Open Access Journals (Sweden)

    Angel Delgado

    2016-01-01

    Full Text Available Objectives: Temporary abdominal closure methods allow for management of open abdomens where immediate primary closure is not possible and/or where repeat abdominal entries are necessary. We assessed pressure mapping and fluid extraction efficiency of three open abdomen dressing systems: ABThera™ Active Abdominal Therapy System, V.A.C.® Abdominal Dressing System, and Barker’s vacuum packing technique. Methods: An in vitro test model was designed to simulate physical conditions present in an open abdomen. The model consisted of a rigid rest platform with elevated central region and a flexible outer layer with centrally located incision. Constant −125 mmHg negative pressure was applied according to the type of system, under simulated dynamic conditions, using albumin-based solution with a viscosity of 14 cP. Data were collected by pressure sensors located circumferentially into three concentric zones: Zone 1 (closest to negative pressure source, Zone 2 (immediately outside of manifolding material edge, and Zone 3 (area most distal from negative pressure source. Each value was the result of approximately 100 pressure readings/zone/experiment with a total of three experiments for each system. Results: Pressure distribution of ABThera Therapy was significantly (p < 0.05 superior to Barker’s vacuum packing technique in all three evaluated zones. Similarly, V.A.C. Abdominal Dressing System pressure distribution was significantly (p < 0.05 improved compared to Barker’s vacuum packing technique in all zones. There were no pressure distribution differences in Zone 1 between ABThera Therapy and V.A.C. Abdominal Dressing System; however, in Zones 2 and 3, ABThera Therapy was significantly (p < 0.05 superior to V.A.C. Abdominal Dressing System. Conclusions: These data suggest that all approaches to negative pressure therapy for open abdomen treatment are not equal. Additional research should be conducted to elucidate clinical

  9. Robust High-Resolution Imaging and Quantitative Force Spectroscopy in Vacuum with Tuned-Oscillator Atomic Force Microscopy.

    Science.gov (United States)

    Schwarz, Udo; Dagdeviren, Omur; GöTzen, Jan; HöLscher, Hendrik; Altman, Eric

    Atomic force microscopy and spectroscopy are based on locally detecting the interactions between a surface and a sharp probe tip. For highest resolution imaging, noncontact modes that avoid tip-sample contact are used; control of the tip's vertical position is accomplished by oscillating the tip and detecting perturbations induced by its interaction with the surface potential. Due to this potential's nonlinear nature, however, achieving reliable control of the tip-sample distance is challenging, so much so that despite its power vacuum-based noncontact atomic force microscopy has remained a niche technique. Here we introduce a new pathway to distance control that prevents instabilities by externally tuning the oscillator's response characteristics. A major advantage of this operational scheme is that it delivers robust position control in both the attractive and repulsive regimes with only one feedback loop, thereby providing an easy-to-implement route to atomic resolution imaging and quantitative tip-sample interaction force measurement. Financial support from National Science Foundation through the Yale Materials Research Science and Engineering Center (Grant No. MRSEC DMR-1119826) is gratefully acknowledged.

  10. Energy Performance Assessment of a 2nd-Generation Vacuum Double Glazing Depending on Vacuum Layer Position and Building Type in South Korea

    Directory of Open Access Journals (Sweden)

    Seung-Chul Kim

    2017-08-01

    Full Text Available (1 Background: The application of high insulation to a building envelope helps reduce the heating load, but increases the cooling load. Evaluating the installation of high insulation glazing to buildings in climate zones with four distinct seasons, as in the case of South Korea, is very important; (2 Methods: This study compared the heating energy performance of four types of glazing, inside vacuum double glazing, outside vacuum double glazing, single vacuum glazing, and low-e double glazing, with fixed low-e coating positions on the inside of the room in a mock-up chamber under the same conditions. The annual energy consumption according to the building type was analyzed using a simulation; (3 Results: As the insulation performance of building envelopes has increased, the energy saving rate of inside vacuum double glazing has been increased further in office buildings. In residential buildings, the energy saving rate of inside vacuum double glazing with a low SHGC (solar heat gain coefficient has become higher than that of outside vacuum double glazing; (4 Conclusions: Since the effects of SHGC on the energy saving rates are greater in high insulation buildings, SHGC should be considered carefully when selecting glazing in climate zones with distinct winter and summer seasons.

  11. The vacuum disconnector

    Energy Technology Data Exchange (ETDEWEB)

    Schellekens, H.

    1989-05-01

    After showing the extended experience of Holec with vacuum disconnectors, the difficulties encountered in developing the type SVS vacuum bottle are indicated. The implications of demands imposed on price and dimensions are translated into design features. The function and the design of the getter is explained to show how Holec guarantees a 20 year approved vacuum in the bottle. Finally, the results of switching tests are mentioned to explain the reliability and capability of the new disconnector. 12 figs.

  12. A strategy for oxygen conditioning at high altitude: comparison with air conditioning.

    Science.gov (United States)

    West, John B

    2015-09-15

    Large numbers of people live or work at high altitude, and many visit to trek or ski. The inevitable hypoxia impairs physical working capacity, and at higher altitudes there is also cognitive impairment. Twenty years ago oxygen enrichment of room air was introduced to reduce the hypoxia, and this is now used in dormitories, hotels, mines, and telescopes. However, recent advances in technology now allow large amounts of oxygen to be obtained from air or cryogenic oxygen sources. As a result it is now feasible to oxygenate large buildings and even institutions such as hospitals. An analogy can be drawn between air conditioning that has improved the living and working conditions of millions of people who live in hot climates and oxygen conditioning that can do the same at high altitude. Oxygen conditioning is similar to air conditioning except that instead of cooling the air, the oxygen concentration is raised, thus reducing the equivalent altitude. Oxygen conditioning on a large scale could transform living and working conditions at high altitude, where it could be valuable in homes, hospitals, schools, dormitories, company headquarters, banks, and legislative settings. Copyright © 2015 the American Physiological Society.

  13. DC photogun vacuum characterization through photocathode lifetime studies

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-02

    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.

  14. Methodology of high-resolution photography for mural condition database

    Science.gov (United States)

    Higuchi, R.; Suzuki, T.; Shibata, M.; Taniguchi, Y.

    2015-08-01

    Digital documentation is one of the most useful techniques to record the condition of cultural heritage. Recently, high-resolution images become increasingly useful because it is possible to show general views of mural paintings and also detailed mural conditions in a single image. As mural paintings are damaged by environmental stresses, it is necessary to record the details of painting condition on high-resolution base maps. Unfortunately, the cost of high-resolution photography and the difficulty of operating its instruments and software have commonly been an impediment for researchers and conservators. However, the recent development of graphic software makes its operation simpler and less expensive. In this paper, we suggest a new approach to make digital heritage inventories without special instruments, based on our recent our research project in Üzümlü church in Cappadocia, Turkey. This method enables us to achieve a high-resolution image database with low costs, short time, and limited human resources.

  15. Vacuum Stability of Standard Model^{++}

    CERN Document Server

    Anchordoqui, Luis A.; Goldberg, Haim; Huang, Xing; Lust, Dieter; Taylor, Tomasz R.; Vlcek, Brian

    2013-01-01

    The latest results of the ATLAS and CMS experiments point to a preferred narrow Higgs mass range (m_h \\simeq 124 - 126 GeV) in which the effective potential of the Standard Model (SM) develops a vacuum instability at a scale 10^{9} -10^{11} GeV, with the precise scale depending on the precise value of the top quark mass and the strong coupling constant. Motivated by this experimental situation, we present here a detailed investigation about the stability of the SM^{++} vacuum, which is characterized by a simple extension of the SM obtained by adding to the scalar sector a complex SU(2) singlet that has the quantum numbers of the right-handed neutrino, H", and to the gauge sector an U(1) that is broken by the vacuum expectation value of H". We derive the complete set of renormalization group equations at one loop. We then pursue a numerical study of the system to determine the triviality and vacuum stability bounds, using a scan of 10^4 random set of points to fix the initial conditions. We show that, if there...

  16. A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence.

    Science.gov (United States)

    Wobrauschek, P; Prost, J; Ingerle, D; Kregsamer, P; Misra, N L; Streli, C

    2015-08-01

    The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm(2) active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

  17. A novel vacuum spectrometer for total reflection x-ray fluorescence analysis with two exchangeable low power x-ray sources for the analysis of low, medium, and high Z elements in sequence

    Energy Technology Data Exchange (ETDEWEB)

    Wobrauschek, P., E-mail: wobi@ati.ac.at; Prost, J.; Ingerle, D.; Kregsamer, P.; Streli, C. [Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna (Austria); Misra, N. L. [Fuel Chemistry Division, Bhabha Atomic Research Centre (BARC), Mumbai 400085 (India)

    2015-08-15

    The extension of the detectable elemental range with Total Reflection X-ray Fluorescence (TXRF) analysis is a challenging task. In this paper, it is demonstrated how a TXRF spectrometer is modified to analyze elements from carbon to uranium. Based on the existing design of a vacuum TXRF spectrometer with a 12 specimen sample changer, the following components were renewed: the silicon drift detector with 20 mm{sup 2} active area and having a special ultra-thin polymer window allowing the detection of elements from carbon upwards. Two exchangeable X-ray sources guarantee the efficient excitation of both low and high Z elements. These X-ray sources were two light-weighted easily mountable 35 W air-cooled low-power tubes with Cr and Rh anodes, respectively. The air cooled tubes and the Peltier-cooled detector allowed to construct a transportable tabletop spectrometer with compact dimensions, as neither liquid nitrogen cooling for the detector nor a water cooling circuit and a bulky high voltage generator for the X-ray tubes are required. Due to the excellent background conditions as a result of the TXRF geometry, detection limits of 150 ng for C, 12 ng for F, and 3.3 ng for Na have been obtained using Cr excitation in vacuum. For Rh excitation, the detection limits of 90 pg could be achieved for Sr. Taking 10 to 20 μl of sample volume, extrapolated detection limits in the ng/g (ppb) range are resulting in terms of concentration.

  18. A compact Ultra-High Vacuum (UHV) compatible instrument for time of flight-energy measurements of slow heavy reaction products

    CERN Document Server

    Kuznetsov, A V; Westerberg, L; Lyapin, V G; Aleklett, K; Loveland, W; Bondorf, J P; Jakobsson, B; Whitlow, H J; El-Bouanani, M

    2000-01-01

    A compact Ultra-High Vacuum (UHV) compatible instrument for time of flight-energy measurements of slow heavy reaction products from nuclear reactions has been designed and tested at the CELSIUS storage ring in Uppsala. The construction is based on MicroChannel Plate (MCP) time detectors of the electron mirror type and silicon p-i-n diodes, and permits the detectors to be stacked side-by-side to achieve large solid angle coverage. This kind of telescope measures the Time of Flight (ToF) and Energy (E) of the particle from which one can reconstruct mass. The combination of an ultra-thin cluster gas-jet target and thin carbon emitter foils allows one to measure heavy residues down to an energy of approx 35 keV/nucleon from the interactions of 400 MeV/nucleon sup 1 sup 6 O with sup n sup a sup t Xe gas targets.

  19. 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.

  20. Mass dependence of vacuum energy

    OpenAIRE

    Fulling, S. A.

    2005-01-01

    The regularized vacuum energy (or energy density) of a quantum field subjected to static external conditions is shown to satisfy a certain partial differential equation with respect to two variables, the mass and the "time" (ultraviolet cutoff parameter). The equation is solved to provide integral expressions for the regularized energy (more precisely, the cylinder kernel) at positive mass in terms of that for zero mass. Alternatively, for fixed positive mass all coefficients in the short-tim...

  1. Dual design resistor for high voltage conditioning and transmission lines

    Science.gov (United States)

    Siggins, Timothy Lynn [Newport News, VA; Murray, Charles W [Hayes, VA; Walker, Richard L [Norfolk, VA

    2007-01-23

    A dual resistor for eliminating the requirement for two different value resistors. The dual resistor includes a conditioning resistor at a high resistance value and a run resistor at a low resistance value. The run resistor can travel inside the conditioning resistor. The run resistor is capable of being advanced by a drive assembly until an electrical path is completed through the run resistor thereby shorting out the conditioning resistor and allowing the lower resistance run resistor to take over as the current carrier.

  2. The effect of sage, sodium erythorbate and a mixture of sage and sodium erythorbate on the quality of turkey meatballs stored under vacuum and modified atmosphere conditions.

    Science.gov (United States)

    Karpińska-Tymoszczyk, M

    2010-12-01

    1. The combined effect of sage (S), sodium erythorbate (SE), a mixture of sage and sodium erythorbate (MIX) and vacuum packaging (VP) and modified atmosphere packaging (MAP) on the quality of cooked turkey meatballs stored at 4°C was investigated. The physicochemical properties (colour, MDA, AV, pH, water activity), microbiological quality characteristics (counts of mesophilic and psychrotrophic bacteria, fungi, coliforms and Clostridium sp.) and flavour attributes of meatballs were determined. 2. The values of the colour parameters L*, a* and b* were affected by the additives and packaging method. The colour of meatballs was better protected by sodium erythorbate than by sage or a mixture of sage and sodium erythorbate. The additives effectively stabilised lipids against oxidation and slowed down hydrolytic changes in turkey meatballs. Sage and a mixture of sage and sodium erythorbate showed stronger antioxidant properties than sodium erythorbate added alone. Products with additives were characterised by better sensory quality than control samples. Sage and MIX prevented the growth of mesophilic and psychrotrophic bacteria. All additives inhibited the growth of coliforms. 3. MAP was more effective than VP in maintaining the microbial and sensory quality stability of cooked turkey meatballs. However, VP appears to be a better method as regards the maintaining of lipid stability in turkey meatballs.

  3. Vacuum and ultravacuum physics and technology

    CERN Document Server

    Bello, Igor

    2018-01-01

    Vacuum technology has enormous impact on human life in many aspects and fields, such as metallurgy, material development and production, food and electronic industry, microelectronics, device fabrication, physics, materials science, space science, engineering, chemistry, technology of low temperature, pharmaceutical industry, and biology. All decorative coatings used in jewelries and various daily products—including shiny decorative papers, the surface finish of watches, and light fixtures—are made using vacuum technological processes. Vacuum analytical techniques and vacuum technologies are pillars of the technological processes, material synthesis, deposition, and material analyses—all of which are used in the development of novel materials, increasing the value of industrial products, controlling the technological processes, and ensuring the high product quality. Based on physical models and calculated examples, the book provides a deeper look inside the vacuum physics and technology.

  4. Photodesorption of gases in vacuum glazing

    Science.gov (United States)

    Ng, N.; Collins, R. E.; So, L.

    2003-09-01

    When samples of vacuum glazing are exposed to sunlight, the pressure within these devices is observed to increase. The major gas species released have been identified using mass spectroscopic techniques, and are found to be carbon monoxide and carbon dioxide rather than water vapor as in thermally degraded vacuum glazing. Different measuring techniques, including the use of a spinning rotor gauge, were developed to study the time dependence of pressure in samples of vacuum glazing during sunlight exposure. The mechanism associated with optical stability of vacuum glazing has been studied. High temperature baking during the evacuation stage of the manufacturing process for vacuum glazing greatly improves the stability of these devices under optical illumination.

  5. Influence of different salting processes on the evolution of the volatile metabolites of vacuum-packed fillets of farmed and wild sea bass (Dicentrarchus labrax) stored under refrigeration conditions: a study by SPME-GC/MS.

    Science.gov (United States)

    Vidal, Natalia P; Manzanos, María J; Goicoechea, Encarnación; Guillén, María D

    2017-02-01

    Fish shelf-life extension is a topic of great interest. In this study the behaviour of salted and unsalted farmed and wild European sea bass (Dicentrarchus labrax) fillets during storage was analysed through the evolution of their volatile metabolites. Farmed and wild sea bass fillets were brine-salted for 15 or 75 min, or dry-salted, vacuum-packed and stored at 4 °C for up to 1 month, and their headspaces were studied by Solid Phase Micro extraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS). At the same storage time, unsalted wild fillets contained, in general, a higher number and abundance of volatile compounds coming from microbiological or endogenous enzymatic activity than unsalted farmed ones. The more intense the salting, the lower the number and abundance of microbiological spoilage metabolites, especially in wild samples. The appearance of oxidation metabolites only in dry-salted wild samples evidences that this kind of salting provokes a certain oxidation in these samples. The better performance of farmed than wild fillets suggests that salted farmed fillets, vacuum-packed and stored under refrigeration conditions, could be a successful alternative to diversify the presence of sea bass in the market. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  6. Fabrication of graphene from graphite by a thermal assisted vacuum arc discharge system

    Science.gov (United States)

    Cheng, Guo-Wei; Chu, Kevin; Chen, Jeng Shiung; Tsai, Jeff T. H.

    2017-04-01

    In this study, graphene was fabricated on copper foils using a high temperature furnace embedded in a vacuum arc discharge method. Combining the advantages of chemical vapor deposition and vacuum arc discharge, single-layer graphene can be fabricated at 600 °C base temperature from the mini furnace embedded with a fast heating via the photon radiation from the vacuum arc to 1100 °C on the substrates' surface. The optimal fabrication condition was determined through a series of experiments on ambient pressure, processing time, arc currents, and the cooling process. Observations by scanning electron microscopy, Raman spectroscopy, and optical microscopy showed that the main products were single-layer graphene, which has a uniform thickness across the entire substrate. The results demonstrated that the combination of a vacuum arc with a thermal method that uses graphite as a carbon source provides a low-cost and straight forward method to synthesize graphene films for graphene-based applications.

  7. Comparison of pesticides and other compounds in carpet dust samples collected from used vacuum cleaner bags and from a high-volume surface sampler.

    Science.gov (United States)

    Colt, J S

    1998-11-01

    Epidemiologic studies of the association between residential pesticide use and cancer risk require an assessment of past pesticide exposures. Pesticide levels in carpet dust are believed to reflect long-term pesticide use. Recent epidemiologic studies have found collection of dust samples using the high-volume surface sampler (HVS3) to be expensive and cumbersome. We compared the levels of pesticides and other compounds in dust obtained from subjects' personal used vacuum cleaner bags to that collected by the HVS3 to see if this simpler method could replace the HVS3 in epidemiologic research. We visited the homes of 15 subjects, took the used bags from their vacuums, and collected carpet dust samples with the HVS3. The samples were analyzed for 42 target compounds: 26 pesticides, 10 polycyclic aromatic hydrocarbons (PAHs), and six polychlorinated biphenyl (PCB) congeners using GC/MS in selected ion monitoring mode. The two methods agreed in detecting the presence of the target compounds between 80% and 100% of the time. Neither sampling method was consistently more sensitive. The median target compound concentrations were similar, and a paired t-test showed no significant differences. For many compounds, the concentrations of compounds in the HVS3 samples were higher than those in the used bag samples at the upper end of the concentration ranges. However, the Spearman rank correlation coefficients were 0.85 or higher for most compounds, indicating that homes would be ranked similarly using both methods. Overall, there appears to be no clear difference in the quality of the pesticide, PAH, or PCB concentration data for the two dust collection methods.

  8. Assessment of vacuum cleaners and vacuum cleaner bags recommended for allergic subjects.

    Science.gov (United States)

    Vaughan, J W; Woodfolk, J A; Platts-Mills, T A

    1999-11-01

    High-quality vacuum cleaners and vacuum cleaner bags are often recommended to allergic patients as a means of reducing indoor allergen exposure. A number of vacuum cleaners on the market today claim to capture 99.9% of particles 0.3 microm or larger entering the vacuum cleaner, and many vacuum cleaner bags are now being sold as microfiltration bags. The purpose of this study was to compare the allergen-trapping abilities of vacuum cleaners and to use a new technique for testing vacuum cleaner bags that are recommended for allergic patients. Vacuum cleaners were tested in an 18-m(3) laboratory room permeated with dust containing high levels of cat allergen by using techniques previously described. Air was sampled with parallel filters in conjunction with a particle counter. The filters were assayed by ELISA for cat allergen (Fel d 1). Vacuum cleaner bags were tested by using a modified dust trap to pull sieved house dust containing a known amount of Fel d 1 across the material used for the bag. Allergen passing through the bag was trapped on a filter covering the exit of the trap and analyzed for Fel d 1. In general, vacuum cleaners designed for allergic patients leaked lower amounts of allergen (vacuum cleaner bags performed poorly (1250-2640 ng recovered) compared with most of the 2- and 3-layer microfiltration bags (0.53-2450 ng recovered). The range of allergen recovered from the 2-layer bags (0.93-2450 ng recovered) highlighted the variability found between manufacturers. The results suggest that although allergen leakage has been reduced, there is still room for improvement. A method of testing allergen leakage by using Fel d 1 should be applied to vacuum cleaners and bags recommended for allergic patients.

  9. Vacuum decay in an interacting multiverse

    CERN Document Server

    Robles-Pérez, S; Bastos, C; Bertolami, O

    2015-01-01

    We examine a new multiverse scenario in which the component universes interact. We focus our attention to the process of "true" vacuum nucleation in the false vacuum within one single element of the multiverse. It is shown that the interactions lead to a collective behaviour that might lead, under specific conditions, to a pre-inflationary phase and ensued distinguishable imprints in the comic microwave background radiation.

  10. Vacuum decay in an interacting multiverse

    Directory of Open Access Journals (Sweden)

    S. Robles-Pérez

    2016-08-01

    Full Text Available We examine a new multiverse scenario in which the component universes interact. We focus our attention to the process of “true” vacuum nucleation in the false vacuum within one single element of the multiverse. It is shown that the interactions lead to a collective behavior that might lead, under specific conditions, to a pre-inflationary phase and ensued distinguishable imprints in the comic microwave background radiation.

  11. Vacuum decay in an interacting multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Robles-Pérez, S. [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado, 14, 06411 Medellín (Spain); Alonso-Serrano, A. [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado, 14, 06411 Medellín (Spain); School of Mathematics and Statistics, Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand); Bastos, C., E-mail: catarina.bastos@tecnico.ulisboa.pt [GoLP, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bertolami, O. [Departamento de Física e Astronomia and Centro de Física do Porto, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2016-08-10

    We examine a new multiverse scenario in which the component universes interact. We focus our attention to the process of “true” vacuum nucleation in the false vacuum within one single element of the multiverse. It is shown that the interactions lead to a collective behavior that might lead, under specific conditions, to a pre-inflationary phase and ensued distinguishable imprints in the comic microwave background radiation.

  12. High Power laser power conditioning system new discharge circuit research

    CERN Document Server

    Li Yi; Peng Han Sheng; Zhou Pei Zhang; Zheng Wan Guo; Guo Lang Fu; Chen Li Hua; Chen De Hui; Lai Gui You; Luan Yong Ping

    2002-01-01

    The new discharge circuit of power conditioning system for high power laser is studied. The theoretical model of the main discharge circuit is established. The pre-ionization circuit is studied in experiment. In addition, the explosion energy of the new large xenon lamp is successfully measured. The conclusion has been applied to 4 x 2 amplifier system

  13. Dual clearance squeeze film damper for high load conditions

    Science.gov (United States)

    Fleming, D. P.

    1985-01-01

    Squeeze film dampers are widely used to control vibrations in aircraft turbine engines and other rotating machinery. However, if shaft unbalance rises appreciably above the design value (e.g., due to a turbine blade loss), a conventional squeeze film becomes overloaded, and is no longer effective in controlling vibration amplitudes and bearing forces. A damper concept characterized by two oil films is described. Under normal conditions, only one low-clearance film is active, allowing precise location of the shaft centerline. Under high unbalance conditions, both films are active, controlling shaft vibration in a near-optimum manner, and allowing continued operation until a safe shutdown can be made.

  14. Discharge-produced plasma extreme ultraviolet (EUV) source and ultra high vacuum chamber for studying EUV-induced processes

    CERN Document Server

    Dolgov, A; Abrikosov, A; Snegirev, E; Krivtsun, V M; Lee, C J; Bijkerk, F

    2014-01-01

    An experimental setup that directly reproduces Extreme UV-lithography relevant conditions for detailed component exposure tests is described. The EUV setup includes a pulsed plasma radiation source, operating at 13.5 nm; a debris mitigation system; collection and filtering optics; and an UHV experimental chamber, equipped with optical and plasma diagnostics. The first results, identifying the physical parameters and evolution of EUV-induced plasmas are presented. Finally, the applicability and accuracy of the in situ diagnostics is briefly discussed.

  15. Vacuum insulation - Panel properties and building applications. HiPTI - High Performance Thermal Insulation - IEA/ECBCS Annex 39 - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Erb, M. (ed.)

    2005-12-15

    This paper takes a look at the properties of vacuum insulation panels (VIP) that have already been developed some time ago for use in appliances such as refrigerators and deep-freezers. Their insulation performance is a factor of five to ten times better than that of conventional insulation. The paper discusses the use of such panels in buildings to provide thin, highly-insulating constructions for walls, roofs and floors. The motivation for examining the applicability of high performance thermal insulation in buildings is discussed, including solutions where severe space limitations and other technical and aesthetic considerations exist. The use of nano-structured materials and laminated foils is examined and discussed. The questions arising from the use of such panels in buildings is discussed and the open questions and risks involved are examined. Finally, an outlook on the introduction of VIP technology is presented and quality assurance aspects are examined. This work was done within the framework of the Task 39 'High Performance Thermal Insulation' of the 'Energy Conservation in Buildings and Community Systems ECBCS' programme of the International Energy Agency IEA.

  16. Vacuum maintenance in hermetically sealed MEMs packages

    Science.gov (United States)

    Corazza, Alessio; Kullberg, Richard C.

    1998-09-01

    Packages for many high sensitivity MEM devices (Micro- Electro-Mechanical devices) such as accelerometers need to operate in a vacuum in order to obtain their full performance. This vacuum is destroyed by the outgassing of species such as hydrogen and water vapor from the surfaces of the package exposed to this vacuum. To control this outgassing a getter is needed. MEM packages are too small to accommodate traditional sintered porous getters. A solution has been developed using a high porosity thick film getter material. The getter consists of a highly porous, mechanically stable, getter coating on a metal substrate. This getter reacts with active gases such as water vapor, hydrogen, oxygen, nitrogen, and carbon monoxide that outgas from the inner surfaces of the package. The physical characteristics and performance of this material will be demonstrated per ASTM sorption testing. The results of this testing will be used to demonstrate the potential for vacuum performance in a real world MEM package.

  17. Investigation of several dynamic processes on solid surfaces and its application to the extreme high vacuum technology. Kotai hyomenjo no doteki katei no kaimei to sono goku koshinku gijutsu eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, D.; Honma, T. (The Univ. of Tokyo, Tokyo (Japan). Inst. of Industrial Science)

    1991-08-26

    This paper makes fundamental studies on several dynamic processes on solid surfaces such as adsorption, desorption, surface segregation, surface precipitation and initial oxidation. The studies aim at applying the information and knowledge obtained to development of an extreme high vacuum technology. Theoretical and technological consideration is given to quantification and precision of surface analytical methods necessary and indispensable for a base technology for the study. The paper pays particular attention to the following three surface analytical methods: Auger electron spectroscopy for a composition analysis, surface extended electron energy loss fine strucutre as a surface short-distance order structural analysis, and thermal sesorption spectroscopy as an adsorption/desorption process analysis. These methods are applied to fundamental studies for development of materials required for creation of an extreme high vacuum. Taking an outgassing phenomenon in the extreme high vacuum as a set of various dynamic processes, quantitative measurement and a mechanism analysis of outgassing are conducted. Actually, the extreme high vacuum is trially produced. 244 refs., 128 figs., 21 tabs.

  18. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Science.gov (United States)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Seiler, A.; Bondarchuk, O.; Hänsel-Ziegler, W.; Risse, T.; Freund, H.-J.

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  19. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  20. Experimental characterization of gasoline sprays under highly evaporating conditions

    Science.gov (United States)

    Khan, Muhammad Mahabat; Sheikh, Nadeem Ahmed; Khalid, Azfar; Lughmani, Waqas Akbar

    2017-12-01

    An experimental investigation of multistream gasoline sprays under highly evaporating conditions is carried out in this paper. Temperature increase of fuel and low engine pressure could lead to flash boiling. The spray shape is normally modified significantly under flash boiling conditions. The spray plumes expansion along with reduction in the axial momentum causes the jets to merge and creates a low-pressure area below the injector's nozzle. These effects initiate the collapse of spray cone and lead to the formation of a single jet plume or a big cluster like structure. The collapsing sprays reduces exposed surface and therefore they last longer and subsequently penetrate more. Spray plume momentum increase, jet plume reduction and spray target widening could delay or prevent the closure condition and limit the penetration (delayed formation of the cluster promotes evaporation). These spray characteristics are investigated experimentally using shadowgraphy, for five and six hole injectors, under various boundary conditions. Six hole injectors produce more collapsing sprays in comparison to five hole injector due to enhanced jet to jet interactions. The spray collapse tendency reduces with increase in injection pressure due high axial momentum of spray plumes. The spray evaporation rates of five hole injector are observed to be higher than six hole injectors. Larger spray cone angles of the six hole injectors promote less penetrating and less collapsing sprays.

  1. Vacuum spin squeezing

    Science.gov (United States)

    Hu, Jiazhong; Chen, Wenlan; Vendeiro, Zachary; Urvoy, Alban; Braverman, Boris; Vuletić, Vladan

    2017-11-01

    We investigate the generation of entanglement (spin squeezing) in an optical-transition atomic clock through the coupling to an optical cavity in its vacuum state. We show that if each atom is prepared in a superposition of the ground state and a long-lived electronic excited state, and viewed as a spin-1/2 system, then the collective vacuum light shift entangles the atoms, resulting in a squeezed distribution of the ensemble collective spin, without any light applied. This scheme reveals that even an electromagnetic vacuum can constitute a useful resource for entanglement and quantum manipulation. By rotating the spin direction while coupling to the vacuum, the scheme can be extended to implement two-axis twisting resulting in stronger squeezing.

  2. Handbook of vacuum technology

    CERN Document Server

    2016-01-01

    This comprehensive, standard work has been updated to remain an important resource for all those needing detailed knowledge of the theory and applications of vacuum technology. With many numerical examples and illustrations to visualize the theoretical issues.

  3. Cold Vacuum Drying Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Located near the K-Basins (see K-Basins link) in Hanford's 100 Area is a facility called the Cold Vacuum Drying Facility (CVDF).Between 2000 and 2004, workers at the...

  4. Vacuum-assisted delivery

    Science.gov (United States)

    ... the birth canal. The vacuum uses a soft plastic cup that attaches to the baby's head with suction. ... a numbing medicine placed in the vagina. The plastic cup will be placed on the baby's head. Then, ...

  5. Mask-free, vacuum-free fabrication of high-conductivity metallic nanowire by spatially shaped ultrafast laser (Conference Presentation)

    Science.gov (United States)

    Wang, Andong; Li, Xiaowei; Qu, Lianti; Lu, Yongfeng; Jiang, Lan

    2017-03-01

    Metal nanowire fabrication has drawn tremendous attention in recent years due to its wide application in electronics, optoelectronics, and plasmonics. However, conventional laser fabrication technologies are limited by diffraction limit thus the fabrication resolution cannot meet the increasingly high demand of modern devices. Herein we report on a novel method for high-resolution high-quality metal nanowire fabrication by using Hermite-Gaussian beam to ablate metal thin film. The nanowire is formed due to the intensity valley in the center of the laser beam while the surrounding film is ablated. Arbitrary nanowire can be generated on the substrate by dynamically adjusting the orientation of the intensity valley. This method shows obvious advantages compared to conventional methods. First, the minimum nanowire has a width of 60 nm (≍1/13 of the laser wavelength), which is much smaller than the diffraction limit. The high resolution is achieved by combining the ultrashort nature of the femtosecond laser and the low thermal conductivity of the thin film. In addition, the fabricated nanowires have good inside qualities. No inner nanopores and particle intervals are generated inside the nanowire, thus endowing the nanowire with good electronic characteristics: the conductivity of the nanowires is as high as 1.2×107 S/m (≍1/4 of buck material), and the maximum current density is up to 1.66×108 A/m2. Last, the nanowire has a good adhesion to the substrates, which can withstand ultrasonic bath for a long time. These advantages make our method a good approach for high-resolution high-quality nanowire fabrication as a complementary method to conventional lithography methods.

  6. Vacuum technology Practice for scientific instruments

    CERN Document Server

    Yoshimura, Nagamitsu

    2008-01-01

    Nanotechnology has reached a level where almost every new development and even every new product uses features of nanoscopic properties of materials. As a consequence, an enormous amount of scientific instruments is used in order to synthesize and analyze new structures and materials. Due to the surface sensitivity of such materials, many of these instruments require ultrahigh vacuum that has to be provided under extreme conditions like very high voltages. In this book, Yoshimura provides a review of the UHV related development during the last decades. His very broad experience in the design enables him to present us this detailed reference. After a general description how to design UHV systems, he covers all important issue in detail, like pumps, outgasing, Gauges, and Electrodes for high voltages. Thus, this book serves as reference for everybody using UVH in his scientific equipment

  7. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry

    2012-01-01

    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  8. A Planck Vacuum Cosmology

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-04-01

    Full Text Available Both the big-bang and the quasi-steady-state cosmologies originate in some type of Planck state. This paper presents a new cosmological theory based on the Planck- vacuum negative-energy state, a state consisting of a degenerate collection of negative- energy Planck particles. A heuristic look at the Einstein field equation provides a con- vincing argument that such a vacuum state could provide a theoretical explanation for the visible universe.

  9. Signal Conditioning in Process of High Speed Imaging

    Directory of Open Access Journals (Sweden)

    Libor Hargas

    2015-01-01

    Full Text Available The accuracy of cinematic analysis with camera system depends on frame rate of used camera. Specific case of cinematic analysis is in medical research focusing on microscopic objects moving with high frequencies (cilia of respiratory epithelium. The signal acquired by high speed video acquisition system has very amount of data. This paper describes hardware parts, signal condition and software, which is used for image acquiring thru digital camera, intelligent illumination dimming hardware control and ROI statistic creation. All software parts are realized as virtual instruments.

  10. High Quality Acquisition of Surface Electromyography - Conditioning Circuit Design

    Science.gov (United States)

    Shobaki, Mohammed M.; Malik, Noreha Abdul; Khan, Sheroz; Nurashikin, Anis; Haider, Samnan; Larbani, Sofiane; Arshad, Atika; Tasnim, Rumana

    2013-12-01

    The acquisition of Surface Electromyography (SEMG) signals is used for many applications including the diagnosis of neuromuscular diseases, and prosthesis control. The diagnostic quality of the SEMG signal is highly dependent on the conditioning circuit of the SEMG acquisition system. This paper presents the design of an SEMG conditioning circuit that can guarantee to collect high quality signal with high SNR such that it is immune to environmental noise. The conditioning circuit consists of four stages; consisting of an instrumentation amplifier that is used with a gain of around 250; 4th order band pass filter in the 20-500Hz frequency range as the two initial stages. The third stage is an amplifier with adjustable gain using a variable resistance; the gain could be changed from 1000 to 50000. In the final stage the signal is translated to meet the input requirements of data acquisition device or the ADC. Acquisition of accurate signals allows it to be analyzed for extracting the required characteristic features for medical and clinical applications. According to the experimental results, the value of SNR for collected signal is 52.4 dB which is higher than the commercial system, the power spectrum density (PSD) graph is also presented and it shows that the filter has eliminated the noise below 20 Hz.

  11. Adsorption geometry, conformation, and electronic structure of 2H-octaethylporphyrin on Ag(111) and Fe metalation in ultra high vacuum.

    Science.gov (United States)

    Borghetti, Patrizia; Di Santo, Giovanni; Castellarin-Cudia, Carla; Fanetti, Mattia; Sangaletti, Luigi; Magnano, Elena; Bondino, Federica; Goldoni, Andrea

    2013-04-14

    Due to the growing interest in the ferromagnetic properties of Fe-octaethylporphyrins (Fe-OEP) for applications in spintronics, methods to produce stable Fe-porphyrins with no Cl atoms are highly demanded. Here, we demonstrate the formation of Fe-OEP layers on Ag(111) single crystal by the ultra high vacuum in situ metalation of the free-base 2H-2,3,7,8,12,13,17,18-octaethylporphyrin (2H-OEP) molecules. The metalation proceeds exactly as in the case of 2H-5,10,15,20-tetraphenylporphyrin (2H-TPP) on the same substrate. An extensive surface characterization by means of X-ray photoemission spectroscopy, valence band photoemission, and NEXAFS with synchrotron radiation light provides information on molecular conformation and electronic structure in the monolayer and multilayer cases. We demonstrate that the presence of the ethyl groups affects the tilt of the adsorbed molecules, the conformation of the macrocycle, and the polarization screening in multilayers, but has only a minor effect in the metalation process with respect to 2H-TPP.

  12. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Meezan, N. B., E-mail: meezan1@llnl.gov; Hopkins, L. F. Berzak; Pape, S. Le; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; Milovich, J. L.; Pak, A. E.; Ross, J. S.; Thomas, C. A.; Benedetti, L. R.; Bradley, D. K.; Celliers, P. M.; Clark, D. S.; Field, J. E.; Haan, S. W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); and others

    2015-06-15

    High Density Carbon (or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a deuterium-tritium (DT) layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a tritium-hydrogen-deuterium (THD) layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 × 10{sup 15} neutrons, 40% of the 1D simulated yield.

  13. Ultra-high vacuum scanning tunnelling microscopy investigation of free radical adsorption to the Si(111)-7 x 7 surface

    Energy Technology Data Exchange (ETDEWEB)

    Guisinger, Nathan P; Elder, Shaun P; Yoder, Nathan L; Hersam, Mark C [Materials Science and Engineering Department, Northwestern University, 2220 Campus Drive, Evanston, IL 60208-3108 (United States)

    2007-01-31

    Room-temperature ultra-high vacuum (UHV) scanning tunnelling microscopy (STM) has been employed to investigate free radical chemistry on the Si(111)-7 x 7 surface with atomic-scale spatial resolution. In particular, due to its single-site binding mechanism and extensive previous study on the Si(100)-2 x 1 surface, the nitroxyl free radical 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) was explored. UHV STM imaging of isolated molecules revealed that TEMPO covalently reacts with adatom dangling bonds with high affinity. By monitoring TEMPO adsorption as a function of surface coverage, TEMPO was also found to preferentially bind to centre adatom sites at the initial stages of adsorption. On the other hand, as the surface coverage increased, TEMPO molecules adsorbed to centre adatoms and corner adatoms approached a ratio of 1:1. At all surface coverage levels, TEMPO showed minimal preference for binding to either the faulted or unfaulted half of the unit cell. Consequently, upon saturation, the TEMPO adlayer exhibited long-range ordering and preserved the underlying 7 x 7 surface reconstruction. This study provides fundamental insight into free radical surface chemistry and suggests a direct pathway for forming nearly perfectly ordered organic adlayers on the Si(111)-7 x 7 surface.

  14. Adsorption geometry, conformation, and electronic structure of 2H-octaethylporphyrin on Ag(111) and Fe metalation in ultra high vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Borghetti, Patrizia; Sangaletti, Luigi [I-LAMP and Department of Mathematics and Physics, Universita Cattolica del Sacro Cuore, Brescia (Italy); Santo, Giovanni Di; Castellarin-Cudia, Carla; Goldoni, Andrea [ST-INSTM micro- and nano-carbon lab., Elettra - Sincrotrone Trieste S.C.p.A., s.s.14 Km. 163.5, 34149 Trieste (Italy); Fanetti, Mattia [ST-INSTM micro- and nano-carbon lab., Elettra - Sincrotrone Trieste S.C.p.A., s.s.14 Km. 163.5, 34149 Trieste (Italy); Istituto Officina dei Materiali-CNR, Laboratorio TASC, s.s. 14 km 163.5, 34149 Trieste (Italy); Magnano, Elena; Bondino, Federica [Istituto Officina dei Materiali-CNR, Laboratorio TASC, s.s. 14 km 163.5, 34149 Trieste (Italy)

    2013-04-14

    Due to the growing interest in the ferromagnetic properties of Fe-octaethylporphyrins (Fe-OEP) for applications in spintronics, methods to produce stable Fe-porphyrins with no Cl atoms are highly demanded. Here, we demonstrate the formation of Fe-OEP layers on Ag(111) single crystal by the ultra high vacuum in situ metalation of the free-base 2H-2,3,7,8,12,13,17,18-octaethylporphyrin (2H-OEP) molecules. The metalation proceeds exactly as in the case of 2H-5,10,15,20-tetraphenylporphyrin (2H-TPP) on the same substrate. An extensive surface characterization by means of X-ray photoemission spectroscopy, valence band photoemission, and NEXAFS with synchrotron radiation light provides information on molecular conformation and electronic structure in the monolayer and multilayer cases. We demonstrate that the presence of the ethyl groups affects the tilt of the adsorbed molecules, the conformation of the macrocycle, and the polarization screening in multilayers, but has only a minor effect in the metalation process with respect to 2H-TPP.

  15. Integrated Cryogenic Propulsion Test Article Thermal Vacuum Hotfire Testing

    Science.gov (United States)

    Morehead, Robert L.; Melcher, J. C.; Atwell, Matthew J.; Hurlbert, Eric A.

    2017-01-01

    In support of a facility characterization test, the Integrated Cryogenic Propulsion Test Article (ICPTA) was hotfire tested at a variety of simulated altitude and thermal conditions in the NASA Glenn Research Center Plum Brook Station In-Space Propulsion Thermal Vacuum Chamber (formerly B2). The ICPTA utilizes liquid oxygen and liquid methane propellants for its main engine and four reaction control engines, and uses a cold helium system for tank pressurization. The hotfire test series included high altitude, high vacuum, ambient temperature, and deep cryogenic environments, and several hundred sensors on the vehicle collected a range of system level data useful to characterize the operation of an integrated LOX/Methane spacecraft in the space environment - a unique data set for this propellant combination.

  16. "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.

  17. Collision condition indicted by High Pressure Phases in a Chondrite

    Science.gov (United States)

    Kato, Y.; Sekine, T.; Kayama, M.; Miyahara, M.; Yamaguchi, A.

    2012-12-01

    It has been generally recognized that there were many collisions during planetary accretion. Chondrites include the materials at the time of formation of the solar system. It is essential to unravel the shock history in meteorites and the parent planet in order to understand such collisional processes. In this study, we investigate a thin section of ordinary chondrite Y-790729 classified as L6 in which high-pressure minerals are found in the about 620-μm-wide shock vein. The mineralogical and chemical features give us detailed information to constrain the shock conditions. We have tried to constrain the P-T condition from the viewpoints of the mineral assemblage and cathodoluminescense (CL) spectroscopy. Y-790729 consists mostly of olivine and pyroxene and has shock veins. To identify high pressure phases, we used an optical microscope, a scanning electron microscope (SEM), micro Raman spectroscopy, and electron probe micro analyzer (EPMA). In addition, scanning electron microscopy-cathodoluminescence (SEM-CL) analysis, detectable shock-induced defect centers, was used to characterize the shock metamorphism in feldspar minerals. The presence of shock vein, maskelynite, and high pressure phases confirms shock record. 7 high pressure phases of ringwoodite, high-pressure clinoenstatite (HPC), majorite, merrillite, lingunite, high-pressure chromite and akimotoite were found in this section. All of them exist only in a shock vein, but maskelynite occurs everywhere in the section. From these observations, it is obvious that the shock vein experienced the high pressure and high temperature generated by shock wave. If some of the high pressure minerals are equilibrated, the P-T condition can be estimated. Based on the equilibrium phase diagram of MgSiO3 polymorphs (Presnall. 1995), the P-T conditions for crystallization of majorite, HPC and akimotoite is about 17 GPa and 1600 oC, because the compositions of the three phases are close to MgSiO3. It is consistent with the

  18. Stabilization flyuorytopodibnoyi structure in oxide vacuum condensate

    Directory of Open Access Journals (Sweden)

    О.М. Заславський

    2006-01-01

    Full Text Available  The influence of the oxide-stabilizer content, M'-cation radius and film deposition temperature on the stabilization of the fluorite-like solid solutions in the zirconium and hafnium oxides-based vacuum condensates, obtained by Laser-evaporating method, was investigated. The optimum parameters of the coatication of the isotropic thermostable coverings was determined. This results were explained by using of the high-speed condensation in vacuum theory.

  19. Realization of matching conditions for high-resolution spectrometers

    CERN Document Server

    Fujita, H; Berg, G P A; Bacher, A D; Foster, C C; Hara, K; Hatanaka, K; Kawabata, T; Noro, T; Sakaguchi, H; Shimbara, Y; Shinada, T; Stephenson, E J; Ueno, H; Yosoi, M

    2002-01-01

    For precise measurements of nuclear-reaction spectra using a beam from an accelerator, a high-resolution magnetic spectrometer is a powerful tool. The full capability of a magnetic spectrometer, however, can be achieved only if the characteristics of the beam coming from the accelerator are matched to those required by the spectrometer by properly adjusting the beam line conditions. The matching methods, lateral dispersion matching, focus matching and also the kinematic correction compensate the spectrum line-broadening effects caused by the beam momentum spread and reaction kinematics. In addition, angular dispersion matching should be performed if good resolution of the scattering angle is important. Diagnostic methods developed to realize these matching conditions for the spectrometers K600 at IUCF and Grand Raiden at RCNP are presented.

  20. Current characteristics of quasi-planar vacuum diodes with explosive-emission cathodes made of various materials at a high-voltage pulse duration of a few nanoseconds

    Science.gov (United States)

    Afanas'ev, K. V.; Vagner, M. I.; Kutenkov, O. P.; Pegel, I. V.; Pribytkov, G. A.; Rostov, V. V.; Tarakanov, V. P.

    2012-12-01

    The currents of 5-ns pulsed high-current electron beams produced in a planar vacuum diode with explosive-emission cathodes made of various materials with no external magnetic field at an average electric field strength in the gap of about 300 kV/cm have been measured and time-integrated observation of the optical luminescence of the cathode surface have been performed. Cathodes with a ceramic bushing and spring metal contacts, with ceramic plates set in a magnetic iron matrix, with blades made of stamped exfoliated graphite (Graflex), with blades made of foil fiberglass plastic, and a composite cathode made of crystalline boron and copper powders were tested. The current carried by one emission center has been estimated to range between 5 and 20 A for various cathodes. For the metal-dielectric cathode, the velocity of expansion of the cathode plasma over the ceramic surface has been estimated as 2·107 cm/s. The lifetimes of the cathodes at a pulse repetition rate of 50 Hz have been investigated.

  1. Effect of non-vacuum thermal annealing on high indium content InGaN films deposited by pulsed laser deposition.

    Science.gov (United States)

    Wang, Tzu-Yu; Ou, Sin-Liang; Shen, Kun-Ching; Wuu, Dong-Sing

    2013-03-25

    InGaN films with 33% and 60% indium contents were deposited by pulsed laser deposition (PLD) at a low growth temperature of 300 °C. The films were then annealed at 500-800 °C in the non-vacuum furnace for 15 min with an addition of N(2) atmosphere. X-ray diffraction results indicate that the indium contents in these two films were raised to 41% and 63%, respectively, after annealing in furnace. In(2)O(3) phase was formed on InGaN surface during the annealing process, which can be clearly observed by the measurements of auger electron spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. Due to the obstruction of indium out-diffusion by forming In(2)O(3) on surface, it leads to the efficient increment in indium content of InGaN layer. In addition, the surface roughness was greatly improved by removing In(2)O(3) with the etching treatment in HCl solution. Micro-photoluminescence measurement was performed to analyze the emission property of InGaN layer. For the as-grown InGaN with 33% indium content, the emission wavelength was gradually shifted from 552 to 618 nm with increasing the annealing temperature to 800 °C. It reveals the InGaN films have high potential in optoelectronic applications.

  2. Potential method for gas production: high temperature co-pyrolysis of lignite and sewage sludge with vacuum reactor and long contact time.

    Science.gov (United States)

    Yang, Xiao; Yuan, Chengyong; Xu, Jiao; Zhang, Weijiang

    2015-03-01

    Lignite and sewage sludge were co-pyrolyzed in a vacuum reactor with high temperature (900°C) and long contact time (more than 2h). Beneficial synergetic effect on gas yield was clearly observed. Gas yield of blend fuel was evidently higher than that of both parent fuels. The gas volume yield, gas lower heating value (LHV), fixed carbon conversion and H2/CO ratio were 1.42 Nm(3)/kg(blend fuel), 10.57 MJ/Nm(3), 96.64% and 0.88% respectively, which indicated this new method a feasible one for gas production. It was possible that sewage sludge acted as gasification agents (CO2 and H2O) and catalyst (alkali and alkaline earth metals) provider during co-pyrolysis, promoting CO2-char and H2O-char gasification which, as a result, invited the improvement of gas volume yield, gas lower heating value and fixed carbon conversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Vacuum induced photoresist outgassing

    Science.gov (United States)

    Waterman, Justin; Mbanaso, Chimaobi; Denbeaux, Gregory

    2008-03-01

    In order to continue the trend toward smaller feature sizes in lithography, new methods of lithography will be needed. A likely method for printing features 32 nm and smaller is extreme ultraviolet (EUV) lithography. EUV allows for features to be printed that are smaller than the current methods can achieve. However, outgassing of the photoresist is a concern for EUV lithography. The outgassed components can lead to contamination of the optics, degrading the reflectivity and hence lowering throughput of the exposure tools. Outgassing due to EUV exposure has been investigated by many groups. However, there were no complete investigations available of vacuum induced outgassing. In this paper, several methods were employed to investigate the outgassing due to vacuum. It was found that the vacuum induced outgassing outgassed a similar number of molecules as the outgassing due to EUV exposure. Furthermore, almost all of the outgassing was completed after about two minutes in vacuum. To mitigate the potential concern of outgassing due to vacuum causing contamination of optics, this work shows that photoresist coated silicon wafers only require about two minutes of pumping prior to insertion near the optics within EUV lithography tools.

  4. Thermophysical Properties Measurement of High-Temperature Liquids Under Microgravity Conditions in Controlled Atmospheric Conditions

    Science.gov (United States)

    Watanabe, Masahito; Ozawa, Shumpei; Mizuno, Akotoshi; Hibiya, Taketoshi; Kawauchi, Hiroya; Murai, Kentaro; Takahashi, Suguru

    2012-01-01

    Microgravity conditions have advantages of measurement of surface tension and viscosity of metallic liquids by the oscillating drop method with an electromagnetic levitation (EML) device. Thus, we are preparing the experiments of thermophysical properties measurements using the Materials-Science Laboratories ElectroMagnetic-Levitator (MSL-EML) facilities in the international Space station (ISS). Recently, it has been identified that dependence of surface tension on oxygen partial pressure (Po2) must be considered for industrial application of surface tension values. Effect of Po2 on surface tension would apparently change viscosity from the damping oscillation model. Therefore, surface tension and viscosity must be measured simultaneously in the same atmospheric conditions. Moreover, effect of the electromagnetic force (EMF) on the surface oscillations must be clarified to obtain the ideal surface oscillation because the EMF works as the external force on the oscillating liquid droplets, so extensive EMF makes apparently the viscosity values large. In our group, using the parabolic flight levitation experimental facilities (PFLEX) the effect of Po2 and external EMF on surface oscillation of levitated liquid droplets was systematically investigated for the precise measurements of surface tension and viscosity of high temperature liquids for future ISS experiments. We performed the observation of surface oscillations of levitated liquid alloys using PFLEX on board flight experiments by Gulfstream II (G-II) airplane operated by DAS. These observations were performed under the controlled Po2 and also under the suitable EMF conditions. In these experiments, we obtained the density, the viscosity and the surface tension values of liquid Cu. From these results, we discuss about as same as reported data, and also obtained the difference of surface oscillations with the change of the EMF conditions.

  5. Characteristic of a triple-cathode vacuum arc plasma source.

    Science.gov (United States)

    Xiang, W; Li, M; Chen, L

    2012-02-01

    In order to generate a better ion beam, a triple-cathode vacuum arc plasma source has been developed. Three plasma generators in the vacuum arc plasma source are equally located on a circle. Each generator initiated by means of a high-voltage breakdown between the cathode and the anode could be operated separately or simultaneously. The arc plasma expands from the cathode spot region in vacuum. In order to study the behaviors of expanding plasma plume generated in the vacuum arc plasma source, a Langmuir probe array is employed to measure the saturated ion current of the vacuum arc plasma source. The time-dependence profiles of the saturated current density of the triple vacuum arc plasma source operated separately and simultaneously are given. Furthermore, the plasma characteristic of this vacuum arc plasma source is also presented in the paper.

  6. New Mathematical Functions for Vacuum System Analysis

    Science.gov (United States)

    Woronowicz, Michael S.

    2017-01-01

    A new bivariate function has been found that provides solutions of integrals having the form u (sup minus eta) e (sup u) du which arise when developing predictions for the behavior of pressure within a rigid volume under high vacuum conditions in the presence of venting as well as sources characterized by power law transient decay over the range [0,1] for eta and for u greater than or equal to 0. A few properties of the new function are explored in this work. For instance the eta equals 1/2 case reproduces the Dawson function. In addition, a slight variation of the solution technique reproduces the exponential integral for eta equals 1. The technique used to generate these functions leads to an approach for solving a more general class of nonlinear ordinary differential equations, with the potential for identifying other new functions that solve other integrals.

  7. In-Vacuum Photogrammetry of a 10-Meter Solar Sail

    Science.gov (United States)

    Meyer, Chris G.; Jones, Thomas W.; Lunsford, Charles B.; Pappa, Richard S.

    2005-01-01

    In July 2004, a 10-meter solar sail structure developed by L Garde, Inc. was tested in vacuum at the NASA Glenn 30-meter Plum Brook Space Power Facility in Sandusky, Ohio. The three main objections of the test were to demonstrate unattended deployment from a stowed configuration, to measure the deployed shape of the sail at both ambient and cryogenic room temperatures, and to measure the deployed structural dynamic characteristics (vibration modes). This paper summarizes the work conducted to fulfill the second test objective. The deployed shape was measured photogrammetrically in vacuum conditions with four 2-megapixel digital video cameras contained in custom made pressurized canisters. The canisters included high-intensity LED ring lights to illuminate a grid of retroreflective targets distributed on the solar sail. The test results closely matched pre-test photogrammetry numerical simulations and compare well with ABAQUS finite-element model predictions.

  8. Improving Vacuum Cleaners

    Science.gov (United States)

    1997-01-01

    Under a Space Act Agreement between the Kirby company and Lewis Research Center, NASA technology was applied to a commercial vacuum cleaner product line. Kirby engineers were interested in advanced operational concepts, such as particle flow behavior and vibration, critical factors to improve vacuum cleaner performance. An evaluation of the company 1994 home care system, the Kirby G4, led to the refinement of the new G5 and future models. Under the cooperative agreement, Kirby had access to Lewis' holography equipment, which added insight into how long a vacuum cleaner fan would perform, as well as advanced computer software that can simulate the flow of air through fans. The collaboration resulted in several successes including fan blade redesign and continuing dialogue on how to improve air-flow traits in various nozzle designs.

  9. Enhanced stability of magnetoelectric gyrators under high power conditions

    Science.gov (United States)

    Leung, Chung Ming; Zhuang, Xin; Gao, Min; Tang, Xiao; Xu, Junran; Li, Jiefang; Zhang, Jitao; Srinivasan, G.; Viehland, D.

    2017-10-01

    In this study, three different coil-based magnetoelectric (ME) gyrators of different geometries, including gyrators with high power output, have been designed and characterized. These included two magnetostrictive/piezoelectric/magnetostrictive (M-P-M) and one piezoelectric/magnetostrictive/piezoelectric (P-M-P) type ME gyrators, which consisted of nickel zinc ferrite (NZFO) and lead zirconate titanate (PZT) ceramic plates. Compared with M-P-M ME gyrators, the P-M-P ones exhibited a higher power efficiency (η) of 85% when operated at resonance under an optimal magnetic bias field (HBias) of 40 Oe at low power conditions. It retained a relatively high efficiency of η = 79% under a high input power density of 2.87 W/cm3. A low reduction in the magnetomechanical coupling and mechanical quality (k33,m and Qm) factors of the NZFO ferrite layer in the ME gyrator explains the resilience of the P-M-P type structure with increasing power drive. The findings open the possibility of using ME gyrators in high power applications.

  10. CHICSi-a compact ultra-high vacuum compatible detector system for nuclear reaction experiments at storage rings. III. readout system

    Science.gov (United States)

    Carlén, L.; Førre, G.; Golubev, P.; Jakobsson, B.; Kolozhvari, A.; Marciniewski, P.; Siwek, A.; van Veldhuizen, E. J.; Westerberg, L.; Whitlow, H. J.; Østby, J. M.

    2004-01-01

    (CHICSi) Celsius Heavy Ion Collaboration Si detector system is a high granularity, modular detector telescope array for operation around the cluster-jet target/circulating beam intersection of the CELSIUS storage ring at the The. Svedberg Laboratory in Uppsala, Sweden. It is able to provide identity and momentum vector of up to 100 charged particles and fragments from proton-nucleus and nucleus-nucleus collisions at intermediate energies, 50-1000AMeV. All detector telescopes as well as the major part of electronic readout system are placed inside the target chamber in ultra-high vacuum (UHV, 10-9-10-7Pa). This requires Very Large Scale Integrated (VLSI) microchip for the spectroscopic signal processing and the generation and transport of digital control signals. Eighteen telescopes, read out with chip-on-board technique by ceramics Mother Boards (MB) and corresponding 18 microchips are mounted on a 450×45mm2 Grand Mother Board (GMB), processed on FR4 glass-fibre material. Each of these 28GMB units contains a daisy-chain organisation of the VLSI chips and associated protection circuits. Analogue-to-digital conversion of the spectroscopic signals is performed on a board outside the chamber which is connected on one side to a power distribution board, directly attached to a UHV mounting flange, and on the other side to the VME-based data acquisition system (CHICSiDAQ). This in its turn is connected via a fibre-optic link to the general TSL acquisition system (SVEDAQ), and in this way data from auxiliary detector systems, read out in CAMAC mode, can be stored in coincidence with CHICSi data.

  11. A rotating quantum vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Lorenci, V.A. de; Svaiter, N.F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1996-11-01

    It was investigated which mapping has to be used to compare measurements made in a rotating frame to those made in an inertial frame. Using a non-Galilean coordinate transformation, the creation-annihilation operators of a massive scalar field in the rotating frame are not the same as those of an inertial observer. This leads to a new vacuum state(a rotating vacuum) which is a superposition of positive and negative frequency Minkowski particles. Polarization effects in circular accelerators in the proper frame of the electron making a connection with the inertial frame point of view were analysed. 65 refs.

  12. Handbook of vacuum physics

    CERN Document Server

    1964-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is a handbook of vacuum physics, with emphasis on the properties of miscellaneous materials such as mica, oils, greases, waxes, and rubber. Accurate modern tables of physical constants, properties of materials, laboratory techniques, and properties of commercial pumps, gauges, and leak detectors are presented. This volume is comprised of 12 chapters and begins with a discussion on pump oils, divided into rotary pump oils and vapor pump oils. The next chapter deals with the properties and applications of greases, including outgassing and vapor pr

  13. High temperature autoclave vacuum seals

    Science.gov (United States)

    Hoffman, J. R.; Simpson, W. G.; Walker, H. M.

    1971-01-01

    Aluminum sheet forms effective sealing film at temperatures up to 728 K. Soft aluminum wire rings provide positive seal between foil and platen. For applications at temperatures above aluminum's service temperature, stainless steel is used as film material and copper wire as sealant.

  14. Analysis of cryopreparated non-dehydrated sample systems by means of a newly developed Tof-SIMS instrument with integrated high-vacuum cutting apparature; Analysen kryopraeparierter nicht-dehydrierter Probensysteme mit Hilfe eines neu entwickelten ToF-SIMS-Instruments mit integrierter Hochvakuumkryoschnittapparatur

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Joerg

    2008-12-05

    Aim of the present thesis was to construct an analysis apparatus, which allows to perform on cryofixed samples a cryocutting respectively cryocracking preparation under vacuum conditions and in the following perform a Tof-SIMS analysis.

  15. A time-resolved current method and TSC under vacuum conditions of SEM: Trapping and detrapping processes in thermal aged XLPE insulation cables

    Energy Technology Data Exchange (ETDEWEB)

    Boukezzi, L. [Materials Science and Informatics Laboratory, MSIL, University of Djelfa, Djelfa (Algeria); Rondot, S., E-mail: sebastien.rondot@univ-reims.fr [Laboratoire d’Ingénierie & Sciences des Matériaux, UFR Sciences, BP1039, 51687 Reims cedex 2 (France); Jbara, O. [Laboratoire d’Ingénierie & Sciences des Matériaux, UFR Sciences, BP1039, 51687 Reims cedex 2 (France); Boubakeur, A. [L.R.E./Laboratory of High Voltage, Polytechnic National School, BP182, EL-Harrach, Algiers (Algeria)

    2017-03-01

    Thermal aging of cross-linked polyethylene (XLPE) can cause serious concerns in the safety operation in high voltage system. To get a more detailed picture on the effect of thermal aging on the trapping and detrapping process of XLPE in the melting temperature range, Thermal Stimulated Current (TSC) have been implemented in a Scanning Electron Microscope (SEM) with a specific arrangement. The XLPE specimens are molded and aged at two temperatures (120 °C and 140 °C) situated close to the melting temperature of the material. The use of SEM allows us to measure both leakage and displacement currents induced in samples under electron irradiation. The first represents the conduction process of XLPE and the second gives information on the trapping of charges in the bulk of the material. TSC associated to the SEM leads to show spectra of XLPE discharge under thermal stimulation using both currents measured after electron irradiation. It was found that leakage current in the charging process may be related to the physical defects resulting in crystallinity variation under thermal aging. However the trapped charge can be affected by the carbonyl groups resulting from the thermo-oxidation degradation and the disorder in the material. It is evidenced from the TSC spectra of unaged XLPE that there is no detrapping charge under heat stimulation. Whereas the presence of peaks in the TSC spectra of thermally aged samples indicates that there is some amount of trapped charge released by heating. The detrapping behavior of aged XLPE is supported by the supposition of the existence of two trap levels: shallow traps and deep traps. Overall, physico-chemical reactions under thermal aging at high temperatures leads to the enhancement of shallow traps density and changes in range of traps depth. These changes induce degradation of electrical properties of XLPE.

  16. Slow waves moving near the openings in highly stressed conditions

    Science.gov (United States)

    Guzev, Michail; Makarov, Vladimir

    2017-04-01

    In situ experiments have shown the unusual deformation waves near the openings on high depth of the construction. Process of the wave spreading is beginning after the mining and has two stages of the zonal mesocracking structure formation and development [1]. Extending in a radial direction, the wave poorly fades with distance. For phenomenon modelling the theoretical decision for non-Eucledian models about opening of round cross-section in strongly compressed rock massif is used [2]. The decision qualitatively repeats behaviour of a wave in a rock mass, adjustment of phenomenological parametres is executed. References [1] Vladimir V. Makarov, Mikhail A. Guzev, Vladimir N. Odintsev, Lyudmila S. Ksendzenko (2016) Periodical zonal character of damage near the openings in highly-stressed rock mass conditions. Journal of Rock Mechanics and Geotechnical Engineering. Volume 8, Issue 2, pp. 164-169. [2] M.A. Guzev, V.V. Makarov, 2007. Deforming and failure of the high stressed rocks around the openings, RAS Edit., Vladivostok, 2007, P. 232 (in Russian).

  17. Precise muon drift tube detectors for high background rate conditions

    CERN Document Server

    Engl, Albert; Dünnweber, Wolfgang

    The muon spectrometer of the ATLAS-experiment at the Large H adron Collider consists of drift tube chambers, which provide the precise m easurement of trajec- tories of traversing muons. In order to determine the moment um of the muons with high precision, the measurement of the position of the m uon in a single tube has to be more accurate than σ ≤ 100 m. The large cross section of proton-proton-collisions and th e high luminosity of the accelerator cause relevant background of neutrons and γ s in the muon spectrome- ter. During the next decade a luminosity upgrade [1] to 5 10 34 cm − 2 s − 1 is planned, which will increase the background counting rates consider ably. In this context this work deals with the further development of the existing drift chamber tech- nology to provide the required accuracy of the position meas urement under high background conditions. Two approaches of improving the dri ft tube chambers are described: • In regions of moderate background rates a faster and more lin ear ...

  18. An amorphous-to-crystalline phase transition within thin silicon films grown by ultra-high-vacuum evaporation and its impact on the optical response

    Science.gov (United States)

    Orapunt, Farida; Tay, Li-Lin; Lockwood, David J.; Baribeau, Jean-Marc; Noël, Mario; Zwinkels, Joanne C.; O'Leary, Stephen K.

    2016-02-01

    A number of thin silicon films are deposited on crystalline silicon, native oxidized crystalline silicon, and optical quality fused quartz substrates through the use of ultra-high-vacuum evaporation at growth temperatures ranging from 98 to 572 °C. An analysis of their grazing incidence X-ray diffraction and Raman spectra indicates that a phase transition, from amorphous-to-crystalline, occurs as the growth temperature is increased. Through a peak decomposition process, applied to the Raman spectroscopy results, the crystalline volume fractions associated with these samples are plotted as a function of the growth temperature for the different substrates considered. It is noted that the samples grown on the crystalline silicon substrates have the lowest crystallanity onset temperature, whereas those grown on the optical quality fused quartz substrates have the highest crystallanity onset temperature; the samples grown on the native oxidized crystalline silicon substrates have a crystallanity onset temperature between these two limits. These resultant dependencies on the growth temperature provide a quantitative means of characterizing the amorphous-to-crystalline phase transition within these thin silicon films. It is noted that the thin silicon film grown on an optical quality fused quartz substrate at 572 °C, possessing an 83% crystalline volume fraction, exhibits an optical absorption spectrum which is quite distinct from that associated with the other thin silicon films. We suggest that this is due to the onset of sufficient long-range order in the film for wave-vector conservation to apply, at least partially. Finally, we use a semi-classical optical absorption analysis to study how this phase transition, from amorphous-to-crystalline, impacts the spectral dependence of the optical absorption coefficient.

  19. Precise muon drift tube detectors for high background rate conditions

    Energy Technology Data Exchange (ETDEWEB)

    Engl, Albert

    2011-08-04

    The muon spectrometer of the ATLAS-experiment at the Large Hadron Collider consists of drift tube chambers, which provide the precise measurement of trajectories of traversing muons. In order to determine the momentum of the muons with high precision, the measurement of the position of the muon in a single tube has to be more accurate than {sigma}{<=}100 {mu}m. The large cross section of proton-proton-collisions and the high luminosity of the accelerator cause relevant background of neutrons and {gamma}s in the muon spectrometer. During the next decade a luminosity upgrade to 5.10{sup 34} cm{sup -2}s{sup -1} is planned, which will increase the background counting rates considerably. In this context this work deals with the further development of the existing drift chamber technology to provide the required accuracy of the position measurement under high background conditions. Two approaches of improving the drift tube chambers are described: - In regions of moderate background rates a faster and more linear drift gas can provide precise position measurement without changing the existing hardware. - At very high background rates drift tube chambers consisting of tubes with a diameter of 15 mm are a valuable candidate to substitute the CSC muon chambers. The single tube resolution of the gas mixture Ar:CO{sub 2}:N{sub 2} in the ratio of 96:3:1 Vol %, which is more linear and faster as the currently used drift gas Ar:CO{sub 2} in the ratio of 97:3 Vol %, was determined at the Cosmic Ray Measurement Facility at Garching and at high {gamma}-background counting rates at the Gamma Irradiation Facility at CERN. The alternative gas mixture shows similar resolution without background. At high background counting rates it shows better resolution as the standard gas. To analyse the data the various parts of the setup have to be aligned precisely to each other. The change to an alternative gas mixture allows the use of the existing hardware. The second approach are drift tubes

  20. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  1. The vacuum strikes back

    CERN Multimedia

    2007-01-01

    "Modern physics has shown that the vacuum, previously thought of as a stated of total nothingness, is really a seething background of virtual particles springing in and out of eixstence until they can seize enough energy to materialize as "real" particles." (1,5 page)

  2. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  3. ISR vacuum system

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    Some of the most important components of the vacuum system are shown. At the left, the rectangular box is a sputter-ion pump inside its bake-out oven. The assembly in the centre includes a sector valve, three roughing valves, a turbomolecular pump, a rotary backing pump and auxiliary equipment. At the right, the small elbow houses a Bayard-

  4. Highly variable Pliocene sea surface conditions in the Norwegian Sea

    Science.gov (United States)

    Bachem, Paul E.; Risebrobakken, Bjørg; De Schepper, Stijn; McClymont, Erin L.

    2017-09-01

    The Pliocene was a time of global warmth with small sporadic glaciations, which transitioned towards the larger-scale Pleistocene glacial-interglacial variability. Here, we present high-resolution records of sea surface temperature (SST) and ice-rafted debris (IRD) in the Norwegian Sea from 5.32 to 3.14 Ma, providing evidence that the Pliocene surface conditions of the Norwegian Sea underwent a series of transitions in response to orbital forcing and gateway changes. Average SSTs are 2 °C above the regional Holocene mean, with notable variability on millennial to orbital timescales. Both gradual changes and threshold effects are proposed for the progression of regional climate towards the Late Pliocene intensification of Northern Hemisphere glaciation. Cooling from 4.5 to 4.3 Ma may be linked to the onset of poleward flow through the Bering Strait. This cooling was further intensified by a period of cool summers due to weak obliquity forcing. A 7 °C warming of the Norwegian Sea at 4.0 Ma suggests a major increase in northward heat transport from the North Atlantic, leading to an enhanced zonal SST gradient in the Nordic Seas, which may be linked to the expansion of sea ice in the Arctic and Nordic Seas. A warm Norwegian Sea and enhanced zonal temperature gradient between 4.0 and 3.6 Ma may have been a priming factor for increased glaciation around the Nordic Seas due to enhanced evaporation and precipitation at high northern latitudes.

  5. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-04

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects.

  6. Furnace brazing under partial vacuum

    Science.gov (United States)

    Mckown, R. D.

    1979-01-01

    Brazing furnace utilizing partial-vacuum technique reduces tooling requirements and produces better bond. Benefit in that partial vacuum helps to dissociate metal oxides that inhibit metal flow and eliminates heavy tooling required to hold parts together during brazing.

  7. Tritium handling in vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Gill, J.T. [Monsanto Research Corp., Miamisburg, OH (United States). Mound Facility; Coffin, D.O. [Los Alamos National Lab., NM (United States)

    1986-10-01

    This report provides a course in Tritium handling in vacuum systems. Topics presented are: Properties of Tritium; Tritium compatibility of materials; Tritium-compatible vacuum equipment; and Tritium waste treatment.

  8. Comparing 193 nm photoresist roughening in an inductively coupled plasma system and vacuum beam system

    Science.gov (United States)

    Titus, M. J.; Nest, D. G.; Chung, T.-Y.; Graves, D. B.

    2009-12-01

    We present a comparison of blanket 193 nm photoresist (PR) roughening and chemical modifications of samples processed in a well-characterized argon (Ar) inductively coupled plasma (ICP) system and an ultra-high vacuum beam system. In the ICP system, PR samples are irradiated with Ar vacuum ultraviolet (VUV) and Ar ions, while in the vacuum beam system, samples are irradiated with either a Xe-line VUV source or Ar-lamp VUV source with Ar ions. Sample temperature, photon flux, ion flux and ion energy are controlled and measured. The resulting chemical modifications to bulk 193 nm PR and surface roughness are analysed with Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy. We demonstrate that under VUV-only conditions in the vacuum beam and ICP (with no substrate bias applied) systems 193 nm PR does not roughen. However, roughness increases with simultaneous high energy (>70 eV) ion bombardment and VUV irradiation and is a function of VUV fluence, substrate temperature and photon-to-ion flux ratio. PR processed in the ICP system experiences increased etching, probably due to release of H- and O-containing gaseous products and subsequent chemical etching, in contrast to samples in the vacuum beam system where etch-products are rapidly pumped away. The surface roughness structure and behaviour, however, remain similar and this is attributed to the synergy between VUV-photon and positive ions.

  9. Highly variable Pliocene sea surface conditions in the Norwegian Sea

    Directory of Open Access Journals (Sweden)

    P. E. Bachem

    2017-09-01

    Full Text Available The Pliocene was a time of global warmth with small sporadic glaciations, which transitioned towards the larger-scale Pleistocene glacial–interglacial variability. Here, we present high-resolution records of sea surface temperature (SST and ice-rafted debris (IRD in the Norwegian Sea from 5.32 to 3.14 Ma, providing evidence that the Pliocene surface conditions of the Norwegian Sea underwent a series of transitions in response to orbital forcing and gateway changes. Average SSTs are 2 °C above the regional Holocene mean, with notable variability on millennial to orbital timescales. Both gradual changes and threshold effects are proposed for the progression of regional climate towards the Late Pliocene intensification of Northern Hemisphere glaciation. Cooling from 4.5 to 4.3 Ma may be linked to the onset of poleward flow through the Bering Strait. This cooling was further intensified by a period of cool summers due to weak obliquity forcing. A 7 °C warming of the Norwegian Sea at 4.0 Ma suggests a major increase in northward heat transport from the North Atlantic, leading to an enhanced zonal SST gradient in the Nordic Seas, which may be linked to the expansion of sea ice in the Arctic and Nordic Seas. A warm Norwegian Sea and enhanced zonal temperature gradient between 4.0 and 3.6 Ma may have been a priming factor for increased glaciation around the Nordic Seas due to enhanced evaporation and precipitation at high northern latitudes.

  10. High cell density production of Deinococcus radiodurans under optimized conditions.

    Science.gov (United States)

    He, Yi

    2009-04-01

    Deinococcus radiodurans is a bacterium being investigated for mechanisms of extreme radiation resistance and for bioremediation of environmental radioactive waste sites. In both fundamental and applied research settings, methods for large-scale production of D. radiodurans are needed. In this study, a systematic investigation was carried out to optimize D. radiodurans production at the 20-L fermentor scale. In defined medium, the phosphate buffer typically used was found to be inhibitory to D. radiodurans growth, and caused cell aggregation. Substitution of HEPES and MOPS buffers for phosphate buffer improved D. radiodurans growth characteristics. Several antifoaming agents were investigated to support large-scale production with submerged aeration, and the defoamer KFO 673 was chosen based on its ability to prevent foaming without affecting D. radiodurans growth. The conventional undefined rich medium tryptone/glucose/yeast extract (TGY) maximally supported D. radiodurans growth to an OD(600) of 10. Using a 'design of experiments' approach, we found glucose, Mg and Mn to be critical in supporting high-density growth of D. radiodurans. The optimal pH and temperature for D. radiodurans growth in large-scale preparations were 7.0 and 37 degrees C, respectively. Growth was carried out in a 20-L fermentor using the newly developed media under the optimal conditions. With addition of 10 g/L glucose, 0.5 g/L MgSO(4) . 7H(2)O, 5 microM MnCl(2) into TGY media, an OD(600) of 40 was achieved.

  11. Quality Factor for the Hadronic Calorimeter in High Luminosity Conditions

    CERN Document Server

    Seixas, Jose; The ATLAS collaboration; Manhaes de Andrade Filho, Luciano; Sotto-Maior-Peralva, Bernardo

    2015-01-01

    The Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of ATLAS experiment and has about 10,000 eletronic channels. An Optimal Filter (OF) has been used to estimate the energy sampled by the calorimeter and applies a Quality Factor (QF) for signal acceptance. An approach using Matched Filter (MF) has also been pursued. In order to cope with the luminosity rising foreseen for LHC operation upgrade, different algorithms have been developed. Currently, the OF measure for signal acceptance is implemented through a chi-square test. At a low luminosity scenario, such QF measure has been used as a way to describe how the acquired signal is compatible to the pulse shape pattern. However, at high-luminosity conditions, due to pile up, this QF acceptance is no longer possible when OF is employed, and the QF becomes a measure to indicate whether the reconstructed signal suffers or not from pile up. Methods are being developed in order to recover the superposed information, and the QF may be us...

  12. Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface

    OpenAIRE

    Maier, Florian; Niedermaier, Inga; Steinrück, Hans-Peter

    2017-01-01

    This perspective analyzes the potential of X-ray photoelectron spectroscopy under ultrahigh vacuum (UHV) conditions to follow chemical reactions in ionic liquids in situ. Traditionally, only reactions occurring on solid surfaces were investigated by X-ray photoelectron spectroscopy (XPS) in situ. This was due to the high vapor pressures of common liquids or solvents, which are not compatible with the required UHV conditions. It was only recently realized that the situation is very different w...

  13. Gases vacuum dedusting and cooling

    Directory of Open Access Journals (Sweden)

    Alexey А. Burov

    2015-03-01

    Full Text Available Represented are the results of operating the ladle degassing vacuum plant (productivity: 120 tons of liquid steel with various dust collectors. The process gases’ cooling and dedusting, obtained in the closed loop buran study, provides opportunity to install a bag filter after that closed loop and its efficient use. Proven is the effectiveness of the cylindrical cyclone replacement with a multichannel (buran dust collector, based on a system of closed-loop (return coupling serially connected curved ducts, where the dusty gas flow rotation axis is vertically positioned. The system of closed-loop serially connected curvilinear channels creates preconditions for the emergence of a negative feedback at the curvilinear gas flow containing transit and circulating flows. These conditions are embodied with circulating flows connecting the in- and outputs of the whole system each channel. The transit flow multiple continuous filtration through the circulating dust layers leads to the formation and accumulation of particles aggregates in the collection chamber. The validity of such a dusty flow control mechanism is confirmed by experimental data obtained in a vacuum chamber. Therefore, replacing one of the two buran’s forevacuum pumps assemblies with the necessary number of curved channels (closed loop is estimated in a promising method.

  14. Nonperturbative QED vacuum birefringence

    Science.gov (United States)

    Denisov, V. I.; Dolgaya, E. E.; Sokolov, V. A.

    2017-05-01

    In this paper we represent nonperturbative calculation for one-loop Quantum Electrodynamics (QED) vacuum birefringence in presence of strong magnetic field. The dispersion relations for electromagnetic wave propagating in strong magnetic field point to retention of vacuum birefringence even in case when the field strength greatly exceeds Sauter-Schwinger limit. This gives a possibility to extend some predictions of perturbative QED such as electromagnetic waves delay in pulsars neighbourhood or wave polarization state changing (tested in PVLAS) to arbitrary magnetic field values. Such expansion is especially important in astrophysics because magnetic fields of some pulsars and magnetars greatly exceed quantum magnetic field limit, so the estimates of perturbative QED effects in this case require clarification.

  15. The effects of electrode cleaning and conditioning on the performance of high-energy, pulsed-power devices

    Energy Technology Data Exchange (ETDEWEB)

    Cuneo, M.E.

    1998-09-01

    High-energy pulsed-power devices routinely access field strengths above those at which broad-area, cathode-initiated, high-voltage vacuum-breakdown occur (> 1e7--3e7 V/m). Examples include magnetically-insulated-transmission-lines and current convolutes, high-current-density electron and ion diodes, high-power microwave devices, and cavities and other structures for electrostatic and RF accelerators. Energy deposited in anode surfaces may exceed anode plasma thermal-desorption creation thresholds on the time-scale of the pulse. Stimulated desorption by electron or photon bombardment can also lead to plasma formation on electrode or insulator surfaces. Device performance is limited above these thresholds, particularly in pulse length and energy, by the formation and expansion of plasmas formed primarily from electrode contaminants. In-situ conditioning techniques to modify and eliminate the contaminants through multiple high-voltage pulses, low base pressures, RF discharge cleaning, heating, surface coatings, and ion- and electron-beam surface treatment allow access to new regimes of performance through control of plasma formation and modification of the plasma properties. Experimental and theoretical progress from a variety of devices and small scale experiments with a variety of treatment methods will be reviewed and recommendations given for future work.

  16. Thermodynamical aspects of running vacuum models

    Energy Technology Data Exchange (ETDEWEB)

    Lima, J.A.S. [Universidade de Sao Paulo, Departamento de Astronomia, Sao Paulo (Brazil); Basilakos, Spyros [Academy of Athens, Research Center for Astronomy and Applied Mathematics, Athens (Greece); Sola, Joan [Univ. de Barcelona, High Energy Physics Group, Dept. d' Estructura i Constituents de la Materia, Institut de Ciencies del Cosmos (ICC), Barcelona, Catalonia (Spain)

    2016-04-15

    The thermal history of a large class of running vacuum models in which the effective cosmological term is described by a truncated power series of the Hubble rate, whose dominant term is Λ(H) ∝ H{sup n+2}, is discussed in detail. Specifically, by assuming that the ultrarelativistic particles produced by the vacuum decay emerge into space-time in such a way that its energy density ρ{sub r} ∝ T{sup 4}, the temperature evolution law and the increasing entropy function are analytically calculated. For the whole class of vacuum models explored here we find that the primeval value of the comoving radiation entropy density (associated to effectively massless particles) starts from zero and evolves extremely fast until reaching a maximum near the end of the vacuum decay phase, where it saturates. The late-time conservation of the radiation entropy during the adiabatic FRW phase also guarantees that the whole class of running vacuum models predicts the same correct value of the present day entropy, S{sub 0} ∝ 10{sup 87}-10{sup 88} (in natural units), independently of the initial conditions. In addition, by assuming Gibbons¨CHawking temperature as an initial condition, we find that the ratio between the late-time and primordial vacuum energy densities is in agreement with naive estimates from quantum field theory, namely, ρ{sub Λ0}/ρ{sub ΛI} 10{sup -123}. Such results are independent on the power n and suggests that the observed Universe may evolve smoothly between two extreme, unstable, non-singular de Sitter phases. (orig.)

  17. Comparison of the conditioning of High Gradient Accelerating Structures

    CERN Document Server

    Degiovanni, Alberto; Giner Navarro, Jorge

    2016-01-01

    Accelerating gradients in excess of 100 MV/m, at very low breakdown rates, have been successfully achieved in numerous CLIC prototype accelerating structures. The conditioning and operational histories of several structures, tested at KEK and CERN, have been compared and there is clear evidence that the conditioning progresses with the number of RF pulses and not the number of breakdowns. This observation opens the possibility that the optimum conditioning strategy, which minimizes the total number of breakdowns the structure is subject to without increasing conditioning time, may be to never exceed the breakdown rate target for operation. The result is also likely to have a strong impact on efforts to understand the physical mechanism underlying conditioning and may lead to preparation procedures which reduce conditioning time.

  18. Potentially Missing Physics of the Early Universe: Nonlinear Vacuum Polarization in Intense Blackbody Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, S Q; Hartemann, F V

    2010-04-13

    The standard Big Bang universe model is mainly based on linear interactions, except during exotic periods such as inflation. The purpose of the present proposal is to explore the effects, if any, of vacuum polarization in the very high energy density environment of the early universe. These conditions can be found today in astrophysical settings and may also be emulated in the laboratory using high intensity advanced lasers. Shortly after the Big Bang, there once existed a time when the energy density of the universe corresponded to a temperature in the range 10{sup 8} - 10{sup 9} K, sufficient to cause vacuum polarization effects. During this period, the nonlinear vacuum polarization may have had significant modifications on the propagation of radiation. Thus the thermal spectrum of the early universe may have been starkly non-Planckian. Measurements of the cosmic microwave background today show a spectrum relatively close to an ideal blackbody. Could the early universe have shown spectral deviations due to nonlinear vacuum effects? If so, is it possible to detect traces of those relic photons in the universe today? Found in galactic environments, compact objects such as blazars and magnetars can possess astronomically large energy densities that far exceed anything that can be created in the laboratory. Their field strengths are known to reach energy levels comparable to or surpassing the energy corresponding to the Schwinger critical field E {approx} 10{sup 18} V/m. Nonlinear vacuum effects become prominent under these conditions and have garnered much interest from the astronomical and theoretical physics communities. The effects of a nonlinear vacuum may be of crucial importance for our understanding of these objects. At energies of the order of the electron rest mass, the most important interactions are described by quantum electrodynamics (QED). It is predicted that nonlinear photon-photon interactions will occur at energies approaching the Schwinger

  19. Fault gouge rheology under confined, high-velocity conditions

    Science.gov (United States)

    Reches, Z.; Madden, A. S.; Chen, X.

    2012-12-01

    We recently developed the experimental capability to investigate the shear properties of fine-grain gouge under confined conditions and high-velocity. The experimental system includes a rotary apparatus that can apply large displacements of tens of meters, slip velocity of 0.001- 2.0 m/s, and normal stress of 35 MPa (Reches and Lockner, 2010). The key new component is a Confined ROtary Cell (CROC) that can shear a gouge layer either dry or under pore-pressure. The pore pressure is controlled by two syringe pumps. CROC includes a ring-shape gouge chamber of 62.5 mm inner diameter, 81.25 mm outer diameter, and up to 3 mm thick gouge sample. The lower, rotating part of CROC contains the sample chamber, and the upper, stationary part includes the loading, hollow cylinder and setting for temperature, and dilation measurements, and pore-pressure control. Each side of the gouge chamber has two pairs of industrial, spring-energized, self-lubricating, teflon-graphite seals, built for particle media and can work at temperature up to 250 ded C. The space between each of the two sets of seals is pressurized by nitrogen. This design generates 'zero-differential pressure' on the inner seal (which is in contact with the gouge powder), and prevents gouge leaks. For the preliminary dry experiments, we used ~2.0 mm thick layers of room-dry kaolinite powder. Total displacements were on the order of meters and normal stress up to 4 MPa. The initial shear was accommodated by multiple internal slip surfaces within the kaolinite layer accommodated as oriented Riedel shear structures. Later, the shear was localized within a thin, plate-parallel Y-surface. The kaolinite layer was compacted at a quasi-asymptotic rate, and displayed a steady-state friction coefficient of ~ 0.5 with no clear dependence on slip velocity up to 0.15 m/s. Further experiments with loose quartz sand (grain size ~ 125 micron) included both dry runs and pore-pressure (distilled water) controlled runs. The sand was

  20. Vacuum distillation device

    Energy Technology Data Exchange (ETDEWEB)

    Hamer, J.A.; Burg, C.J. Van Der; Kanbier, D.; Heijden, P. Van Der.

    1990-09-18

    This invention relates to a vacuum distillation device comprising a vacuum distillation column, a furnace provided with a heat exchange tube, and a connecting conduit between the column and the heat exchange tube. Such a device is used to fractionate a hydrocarbon-containing feed sometimes referred to as long residue. An object of this invention is to provide a vacuum distillation device which allows vaporization of a major part of the feed upstream of the column inlet. To this end, the device according to the invention comprises a vacuum distillation device as described above, in which the inner diameter of the heat exchange tube increases along its length to between 2.4 and 3 times the inner diameter of the tube inlet, and in which the inner diameter of the connecting conduit gradually increases along its length to between 2.5 and 5.4 times the inner diameter of the tube outlet. During normal operation of the device of the invention, only less than 50 wt % of the feed is vaporized in the heat exchange tube in the furnace, and more feed is vaporized in the connecting conduit, so that at the outlet end of the conduit the feed comprises about 0.9 kg vapor per kg of feed. The invention provides improved heat transfer in the heat exchange tubes such that fouling is reduced, consequently more heat can be applied per unit of time in the heat exchange tube. This allows either heating of the feed to a higher temperature or increasing the throughput for the same temperature.

  1. Inelastic X-ray scattering experiments at extreme conditions: high temperatures and high pressures

    Directory of Open Access Journals (Sweden)

    S.Hosokawa

    2008-03-01

    Full Text Available In this article, we review the present status of experimental techniques under extreme conditions of high temperature and high pressure used for inelastic X-ray scattering (IXS experiments of liquid metals, semiconductors, molten salts, molecular liquids, and supercritical water and methanol. For high temperature experiments, some types of single-crystal sapphire cells were designed depending on the temperature of interest and the sample thickness for the X-ray transmission. Single-crystal diamond X-ray windows attached to the externally heated high-pressure vessel were used for the IXS experiment of supercritical water and methanol. Some typical experimental results are also given, and the perspective of IXS technique under extreme conditions is discussed.

  2. Bake-Out Mobile Controls for Large Vacuum Systems

    CERN Document Server

    Blanchard, S; Gomes, P; Pereira, H; Kopylov, L; Merker, S; Mikheev, M

    2014-01-01

    Large vacuum systems at CERN (Large Hadron Collider - LHC, Low Energy Ion Rings - LEIR...) require bake-out to achieve ultra-high vacuum specifications. The bake-out cycle is used to decrease the outgassing rate of the vacuum vessel and to activate the Non-Evaporable Getter (NEG) thin film. Bake-out control is a Proportional-Integral-Derivative (PID) regulation with complex recipes, interlocks and troubleshooting management and remote control. It is based on mobile Programmable Logic Controller (PLC) cabinets, fieldbus network and Supervisory Control and Data Acquisition (SCADA) application. The CERN vacuum installations include more than 7 km of baked vessels; using mobile cabinets reduces considerably the cost of the control system. The cabinets are installed close to the vacuum vessels during the time of the bake-out cycle. Mobile cabinets can be used in any of the CERN vacuum facilities. Remote control is provided through a fieldbus network and a SCADA application

  3. HiPTI - High Performance Thermal Insulation, Annex 39 to IEA/ECBCS-Implementing Agreement. Vacuum insulation in the building sector. Systems and applications

    Energy Technology Data Exchange (ETDEWEB)

    Binz, A.; Moosmann, A.; Steinke, G.; Schonhardt, U.; Fregnan, F. [Fachhochschule Nordwestschweiz (FHNW), Muttenz (Switzerland); Simmler, H.; Brunner, S.; Ghazi, K.; Bundi, R. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Duebendorf (Switzerland); Heinemann, U.; Schwab, H. [ZAE Bayern, Wuerzburg (Germany); Cauberg, H.; Tenpierik, M. [Delft University of Technology, Delft (Netherlands); Johannesson, G.; Thorsell, T. [Royal Institute of Technology (KTH), Stockholm (Sweden); Erb, M.; Nussbaumer, B. [Dr. Eicher und Pauli AG, Basel and Bern (Switzerland)

    2005-07-01

    This final report on vacuum insulation panels (VIP) presents and discusses the work done under IEA/Energy Conservation in Buildings and Community Systems (ECBCS) Annex 39, subtask B on the basis of a wide selection of reports from practice. The report shows how the building trade deals with this new material today, the experience gained and the conclusions drawn from this work. As well as presenting recommendations for the practical use of VIP, the report also addresses questions regarding the effective insulation values to be expected with current VIP, whose insulation performance is stated as being a factor of five to eight times better than conventional insulation. The introduction of this novel material in the building trade is discussed. Open questions and risks are examined. The fundamentals of vacuum insulation panels are discussed and the prerequisites, risks and optimal application of these materials in the building trade are examined.

  4. PARAFFIN SEPARATION VACUUM DISTILLATION

    Directory of Open Access Journals (Sweden)

    Zaid A. Abdulrahman

    2013-05-01

    Full Text Available Simulated column performance curves were constructed for existing paraffin separation vacuum distillation column in LAB plant (Arab Detergent Company/Baiji-Iraq. The variables considered in this study are the thermodynamic model option, top vacuum pressure, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates composition were constructed. Four different thermodynamic model options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.The simulated results show that about 2% to 8 % of paraffin (C10, C11, C12, & C13 present at the bottom stream which may cause a problem in the LAB plant. The major variations were noticed for the top temperature & the  paraffin weight fractions at bottom section with top vacuum pressure. The bottom temperature above 240 oC is not recommended because the total bottom flow rate decreases sharply, where as  the weight fraction of paraffins decrease slightly. The study gives evidence about a successful simulation with CHEMCAD

  5. Prevention of Surgical Site Infection After Ankle Surgery Using Vacuum-Assisted Closure Therapy in High-Risk Patients With Diabetes.

    Science.gov (United States)

    Zhou, Zhen-Yu; Liu, Ya-Ke; Chen, Hong-Lin; Liu, Fan

    2016-01-01

    Patients with diabetes have a high risk of surgical site infection (SSI) after ankle surgery. The aim of the present study was to investigate the efficacy of vacuum-assisted closure (VAC) in the prevention of SSI after ankle surgery compared with the efficacy of standard moist wound care (SMWC). A retrospective study was performed of unstable ankle fractures for surgical fixation in patients with diabetes from January 2012 to December 2014. VAC and SMWC were used for surgical incision coverage. The primary outcome was the incidence of SSI, and the secondary outcomes were the length of hospital stay and crude hospital costs. The data from 76 patients were analyzed, with 22 (28.95%) in the VAC group and 54 (71.05%) in the SMWC group. The incidence of SSI was 4.6% in the VAC group compared with 27.8% in the SMWC group (chi-square 5.076; p = .024), and the crude odds ratio for SSI in the VAC group was 0.124 (95% confidence interval 0.002 to 0.938). The length of hospital stay was lower in the VAC group than in the SMWC group (12.6 ± 2.7 days and 15.2 ± 3.5 days, respectively; t = 3.122, p = .003). The crude hospital costs were also lower in the VAC group than in the SMWC group (Chinese yuan 8643.2 ± 1195.3 and 9456.2 ± 1106.3, respectively; t = 2.839, p = .006). After logistic regression analysis, the adjusted odds ratio for the total SSI rate comparing VAC and SMWC was 0.324 (95% confidence interval 0.092 to 0.804; p = .021). Compared with SMWC, VAC can decrease the SSI rate after ankle surgery in patients with diabetes. This finding should be confirmed by prospective, randomized controlled clinical trials. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Inter-Batch Variation and the Effect of Casting Vacuum on Ballistic and Mechanical Properties of a High Performing Cast Composite Rocket Propellant

    Science.gov (United States)

    2014-12-01

    Tensile testing of propellant in the form of ‘ dog bones’ or uniaxial tensile test pieces cut from cast slabs of propellant was performed to assess inter... dog bones were cut from the top of the mould. It is possible that the strands for both partial and full vacuum had a slightly higher solids content... Behaviour of AP/HTPB Propellant Using Coarse and Fine AP Particles. Propellants, Explosives, Pyrotechnics, 2011. 36: p. 57-64. 9. Smith, P.C

  7. Vacuum Attachment for XRF Scanner

    Science.gov (United States)

    Schramm, Harry F.; Kaiser, Bruce

    2005-01-01

    Vacuum apparatuses have been developed for increasing the range of elements that can be identified by use of x-ray fluorescent (XRF) scanners of the type mentioned in the two immediately preceding articles. As a consequence of the underlying physical principles, in the presence of air, such an XRF scanner is limited to analysis of chlorine and elements of greater atomic number. When the XRF scanner is operated in a vacuum, it extends the range of analysis to lower atomic numbers - even as far as aluminum and sodium. Hence, more elements will be available for use in XRF labeling of objects as discussed in the two preceding articles. The added benefits of the extended capabilities also have other uses for NASA. Detection of elements of low atomic number is of high interest to the aerospace community. High-strength aluminum alloys will be easily analyzed for composition. Silicon, a major contaminant in certain processes, will be detectable before the process is begun, possibly eliminating weld or adhesion problems. Exotic alloys will be evaluated for composition prior to being placed in service where lives depend on them. And in the less glamorous applications, such as bolts and fasteners, substandard products and counterfeit items will be evaluated at the receiving function and never allowed to enter the operation

  8. Coil-On-Plug Ignition for LOX/Methane Liquid Rocket Engines in Thermal Vacuum Environments

    Science.gov (United States)

    Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

    2017-01-01

    A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX) / liquid methane rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/methane propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. In order to successfully demonstrate ignition reliability in the vacuum conditions and eliminate corona discharge issues, a coil-on-plug ignition system has been developed. The ICPTA uses spark-plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark-plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp.-2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, Plum Brook testing demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/methane propulsion systems in future spacecraft.

  9. Particle emission characteristics of filter-equipped vacuum cleaners.

    Science.gov (United States)

    Trakumas, S; Willeke, K; Grinshpun, S A; Reponen, T; Mainelis, G; Friedman, W

    2001-01-01

    Industrial vacuum cleaners with final high-efficiency particulate air (HEPA) filters traditionally have been used for cleanup operations in which all of the nozzle-entrained dust must be collected with high efficiency, for example, after lead-based paint abatement in homes. In this study household vacuum cleaners ranging from $70 to $650 and an industrial vacuum cleaner costing more than $1400 were evaluated relative to their collection efficiency immediately after installing new primary dust collectors in them. Using newly developed testing technology, some of the low-cost household vacuum cleaners equipped with a final HEPA filter were found to have initial overall filtration efficiencies comparable to those of industrial vacuum cleaners equipped with a final HEPA filter. The household vacuum cleaners equipped with a final HEPA filter efficiently collect about 100% of the dry dust entrained by the nozzle. For extensive cleaning efforts and for vacuum cleaning of wet surfaces, however, industrial vacuum cleaners may have an advantage, including ruggedness and greater loading capacity. The methods and findings of this study are applicable to field evaluations of vacuum cleaners.

  10. The Planck Vacuum and the Schwarzschild Metrics

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-07-01

    Full Text Available The Planck vacuum (PV is assumed to be the source of the visible universe. So under conditions of sufficient stress, there must exist a pathway through which energy from the PV can travel into this universe. Conversely, the passage of energy from the visible universe to the PV must also exist under the same stressful conditions. The following examines two versions of the Schwarzschild metric equation for compatability with this open-pathway idea.

  11. Recent advances in vacuum sciences and applications

    Science.gov (United States)

    Mozetič, M.; Ostrikov, K.; Ruzic, D. N.; Curreli, D.; Cvelbar, U.; Vesel, A.; Primc, G.; Leisch, M.; Jousten, K.; Malyshev, O. B.; Hendricks, J. H.; Kövér, L.; Tagliaferro, A.; Conde, O.; Silvestre, A. J.; Giapintzakis, J.; Buljan, M.; Radić, N.; Dražić, G.; Bernstorff, S.; Biederman, H.; Kylián, O.; Hanuš, J.; Miloševič, S.; Galtayries, A.; Dietrich, P.; Unger, W.; Lehocky, M.; Sedlarik, V.; Stana-Kleinschek, K.; Drmota-Petrič, A.; Pireaux, J. J.; Rogers, J. W.; Anderle, M.

    2014-04-01

    Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid-liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented.

  12. Vacuum pumping for controlled thermonuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    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/sup 0/K to pump helium, but the unburned deuterium-tritium and other impurities could be pumped with cryocondensation panels (4.2/sup 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.

  13. Determination of Kicker Vacuum Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-15

    This note examines the effect of elevated vacuum pressures in the kicker region of the DARHT 2nd Axis which can lead to changes in the beam tune due to the long pulse length. The kicker uses Rexolite as an insulator supporting the electrodes. Rexolite is hygroscopic resulting is a large outgassing rate and prolonged pump down times after exposure to atmospheric conditions. LAMDA [1] is used to simulate the effect of ionization of the residual gas resulting in partial space charge neutralization and changes to the tune between the beginning and end of the pulse. The effect of the ion-hose instability is also examined. The purpose of this note is to establish/validate the required pressure in the downstream transport.

  14. Modeling Vacuum Arcs On Spacecraft Solar Panel Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft charging and subsequent vacuum arcing poses a significant threat to satellites in LEO and GEO plasma conditions. Localized arc discharges can cause a...

  15. Vacuum silicon photomultipliers: Recent developments

    Energy Technology Data Exchange (ETDEWEB)

    Barbarino, Giancarlo [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); INFN Napoli (Italy); Barbato, Felicia Carla Tiziana [INFN Napoli (Italy); Campajola, Luigi [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); Asmundis, Riccardo de [INFN Napoli (Italy); De Rosa, Gianfranca [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); Mollo, Carlos Maximiliano [INFN Napoli (Italy); Vivolo, Daniele, E-mail: vivolo@na.infn.it [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); INFN Napoli (Italy)

    2013-08-01

    VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a modern hybrid, high gain, silicon based photodetector based on the combination of a SiPM with a hemispherical vacuum glass PMT standard envelope. In such a device photoelectrons emitted by the photocathode are accelerated and focused by an electric field towards a small focal area covered by the SiPM which therefore acts as an amplifier, thus substituting the classical dynode chain of a PMT. With a view to the realization of a first prototype of VSiPMT our group is carrying out a preliminary work aimed at the study of SiPM performances as an electron detector, including an accurate Geant4-based simulation of the interaction between SiPM and electron beams. In order to perform a full characterization of the SiPM we developed an experimental setup for the extraction and the acceleration of a beam of backward secondary electrons emitted after the bombardment of a carbon foil by a proton beam extracted in a TTT-3 accelerator.

  16. THE THERMOELECTRIC VACUUM CROCK-POT AND THE AUTOMATED WORKPLACE FOR ITS RESEARCH AS A CONTROL OBJECT

    Directory of Open Access Journals (Sweden)

    S. Hudz

    2017-08-01

    Full Text Available The technologies of thermal treatment in vacuum are widely used in various fields of production, in particular in the food industry, but their application at farms, hotels or a for domestic purposes is limited because of the big sizes, high cost of processing equipment and complexity of its management at realization of foodstuff processing. Products, made with use of vacuum technologies, keep much more useful substances because they aren't exposed to high-temperature processing and oxidation while preparation. Development and production of the small-sized equipment for realization of heat treatment processes of foodstuff in vacuum would create technical and economic conditions for implementation of temperature processing processes of foodstuff at farms, hotels and even at home that would promote creation of new food, development of new recipes and, in general, development of the new direction in cookery. So the article describes the problem of equipment construction for the process of thermal processing of food in vacuum such as cooking jam, concentration of juices and dairy products, distillation, drying, pickling, and the possibility of building inexpensive compact vacuum unit for the implementation of these processes (crock-pot for use at hotels, farms and even for domestic purposes. The analysis of technological schemes for energy efficient evaporation process in vacuum crock-pot is provided. The developed technological scheme of vacuum crock-pot with thermoelectric converters and principle of its operation are considered. Microprocessor block diagram of a multichannel data acquisition system consisting workstation for investigation of thermoelectric vacuum crock-pot as a control object is presented and control algorithms helping to reduce energy consumption and to increase operational reliability in implementing processes and the quality of ready-made products are provided.

  17. Vacuum lubricants based on neutral oil

    Energy Technology Data Exchange (ETDEWEB)

    Artem' yeva, V.P.; Potanina, V.A.; Kucheryavaya, N.N.; Orlova, S.N.; Gorbacheva, S.G.

    1983-01-01

    Basic parameters for high-vacuum pumps such as minimal residual vapor pressure, rapid operation and vacuum collapse resistance depend on type and properties of hydraulic fluids, which include mineral oils, esters of organic alcohols and acids and organic silicon compounds. Mineral oils have been used most because of their thermal stability and low cost. This article reports studies of such oils based on domestic naphthene-paraffin hydrocarbons and medical vaseline processed from Balakhan petroleum. Neutral naphthene oil with 90% saturated hydrocarbons was found suitable for vacuum oils after purification and distillation. Its origin as a by-product of sulfonate additive production, and resultant low cost, recommend this oil for full production.

  18. Development of vacuum die-casting process

    Directory of Open Access Journals (Sweden)

    Masashi Uchida

    2009-05-01

    Full Text Available The vacuum die-casting process, started 25 years ago in Japan, has been widely applied. This technology contributes very much to improvement of castings quality. The main factor causing the defects of die castings is the trapped air in the mold cavity, while the key technology of vacuum die-casting process is to avoid the trapped air effectively by evacuating the cavity before casting. At the same time, due to the shot speed and the casting pressure reduced in half, the service life of the die is prolonged and the productivity is enhanced, as well. Vacuum die-casting process is of great signifi cance in improving the die castings quality and making up the shortcomings of super-high-speed shot casting.

  19. 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.

  20. Vacuum ultraviolet spectroscopy I

    CERN Document Server

    Samson, James A; Lucatorto, Thomas

    1998-01-01

    This volume is for practitioners, experimentalists, and graduate students in applied physics, particularly in the fields of atomic and molecular physics, who work with vacuum ultraviolet applications and are in need of choosing the best type of modern instrumentation. It provides first-hand knowledge of the state-of-the-art equipment sources and gives technical information on how to use it, along with a broad reference bibliography.Key Features* Aimed at experimentalists who are in need of choosing the best type of modern instrumentation in this applied field* Contains a detailed chapter on la

  1. Efficient Phosphorescent OLEDS Based on Vacuum Deposition ...

    African Journals Online (AJOL)

    Thereby, we demonstrate high-efficiency organic light-emitting diodes by incorporating a double emission layer {i.e. both doped with the green phosphorescent dye tris(phenylpyridine)iridium [Ir(ppy)3]} into p-i-n-type device structure based on vacuum deposition technology. The intrinsic and doped transports layers are ...

  2. Nutrition of pigs kept under low and high sanitary conditions

    NARCIS (Netherlands)

    Meer, van der Yvonne

    2017-01-01

    It is economically and environmentally important to match the nutrient supply to the nutrient requirements in pig production. Until now, the effects of different sanitary conditions on energy and nutrient requirements are not implemented in recommendations for nutrient composition of pig diets.

  3. 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...

  4. Compact Vacuum Pump for Titan Lander Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For a number of years Creare has developed, fabricated, and tested highly miniaturized, high vacuum pumps specifically designed for mass spectrometers used on NASA...

  5. Vacuum science, technology, and applications

    CERN Document Server

    Naik, Pramod K

    2018-01-01

    Vacuum plays an important role in science and technology. The study of interaction of charged particles, neutrals and radiation with each other and with solid surfaces requires a vacuum environment for reliable investigations. Vacuum has contributed immensely to advancements made in nuclear science, space, metallurgy, electrical/electronic technology, chemical engineering, transportation, robotics and many other fields. This book is intended to assist students, scientists, technicians and engineers to understand the basics of vacuum science and technology for application in their projects. The fundamental theories, concepts, devices, applications, and key inventions are discussed.

  6. Linear and nonlinear filters under high power microwave conditions

    Directory of Open Access Journals (Sweden)

    F. Brauer

    2009-05-01

    Full Text Available The development of protection circuits against a variety of electromagnetic disturbances is important to assure the immunity of an electronic system. In this paper the behavior of linear and nonlinear filters is measured and simulated with high power microwave (HPM signals to achieve a comprehensive protection against different high power electromagnetic (HPEM threats.

  7. Vacuum stability and perturbativity of SU(3) scalars

    Science.gov (United States)

    Heikinheimo, Matti; Kannike, Kristjan; Lyonnet, Florian; Raidal, Martti; Tuominen, Kimmo; Veermäe, Hardi

    2017-10-01

    We calculate the vacuum stability conditions and renormalisation group equations for the extensions of standard model with a higher colour multiplet scalar up to the representation 15' that leaves the strong interaction asymptotically free. In order to find the vacuum stability conditions, we calculate the orbit spaces for the self-couplings of the higher multiplets, which for the representations 15 and 15' of SU(3) c are highly complicated. However, if the scalar potential is linear in orbit space variables, it is sufficient to know the convex hull of the orbit space. Knowledge of the orbit spaces also facilitates the minimisation of the potentials. In contrast to the self-couplings of other multiplets, we find that the scalar quartic couplings of the representations 3 and 8 walk rather than run, remaining nearly constant and perturbative over a vast energy range. We describe the conditions for walking couplings using a schematic model. With these technical results at hand we revise earlier results of generation of new scales with large SU(3) c scalar multiplets. Our results are easily extendable to models of new physics with additional SU(3) or SU( N) gauge symmetries.

  8. Nonlinear Creep Model for Deep Rock under High Stress and High Pore Water Pressure Condition

    Directory of Open Access Journals (Sweden)

    Xie Yuanguang

    2016-05-01

    Full Text Available Conventional triaxial compression creep experiments for deep sandstone under high confining pressure and high pore water pressure were carried out, in order to predict the creep response of deep rock under these conditions. A nonlinear viscoelastic-plastic creep constitutive model was proposed based on the experimental results. The theory of component model was used as a basis for the formulation of this model. First, by using mathematical fitting and analogy, a new nonlinear viscous component was introduced based on the properties of the creep curves during the tertiary stage. Second, a timer component to judge whether the creep can get into the tertiary stage was presented. Finally, a nonlinear creep model was proposed. Results showed good agreement between theory curves from the nonlinear creep model and experimental data. This model can be applied to predict deep rock creep responses under high stress and high pore water pressure conditions. Hence, the obtained conclusions in this study are beneficial to deep rock engineering.

  9. Manufacture and cost of vacuum glazing

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, J.D. [San Diego State Univ., CA (United States); Collins, R.E. [Univ. of Sydney (Australia)

    1995-12-31

    The vacuum glazing project at the University of Sydney has progressed to the point where the main features of the vacuum glazing design are determined well. Over 500 glazings with areas up to one square meter have been formed. The stresses to which these glazings are or may be exposed have been studied extensively. The durability of the glazing structure and the internal vacuum has been demonstrated. Vacuum glazing of the type designed and formed at the University of Sydney has a center-of-glazing thermal conductance as low as 0.85 and 1.2 Wm{sup -2}/K{sup -1}, for glazings with two and one internal low emittance coatings, respectively. A method for the manufacture of the vacuum glazing is outlined from which the cost to manufacture the glazing can be estimated. A cost at the factory of about $40{+-}7 m{sup -2} for vacuum glazing using two sheets of low-e glass and about $32{+-}6 m{sup -2} for glazing using one sheet of low-e glass is obtained, when production volume is approx. 10{sup 5} m{sup 2}yr{sup -1} and is partially automated. This is about 25% higher than the estimated manufacturing cost of the high thermal resistance, argon filled, double glazing utilizing low-e glass, which are currently in production and being sold in the United States, Europe and Japan. These glazings typically have center-of-glazing thermal conductances of about 1.1 Wm{sup -2}K{sup -1} or more. 11 refs., 2 figs., 7 tabs.

  10. An overview of the technology of vacuum glazing

    Energy Technology Data Exchange (ETDEWEB)

    Simko, T. M.; Collins, R. E.; Turner, G. M.; Tang, J-Z. [Sydney Univ., NSW (Australia). School of Physics; Fischer-Cripps, A. C. [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Garrison, J. D. [San Diego State Univ., CA (United States). Dept. of Physics

    1995-12-01

    The technology of vacuum glazing was discussed as an alternative to the argon and krypton gas fills in double paned windows. A vacuum between the two panes insulates in the same way that a Dewar flask insulates. Aside from patent literature, few reports have been published in the scientific literature on the use of vacuum glazing. Over 500 samples of vacuum glazing have been produced in the laboratory. Manufacturing methods have been similar to those used in the production of picture tubes. It was shown that high internal vacuums may be maintained over several years. Design of vacuum glazing required a trade-off between heat flow through pillars and internal stresses. Modelling showed that internal stresses were tolerable for temperature differentials of up to 40 degrees. Relationships between mechanical stress, fracture probability and thermal performance were in the process of being quantified. Physical mechanisms of vacuum degradation were also being studied. Practical applicability of vacuum glazing will depend on the extent to which field trials confirm results of lab experiments and numerical modelling. High thermal insulation, with a very thin glazing and moderate cost were expected in the future. 4 figs., 14 refs.

  11. Flow separation in rocket nozzles under high altitude condition

    Science.gov (United States)

    Stark, R.; Génin, C.

    2017-01-01

    The knowledge of flow separation in rocket nozzles is crucial for rocket engine design and optimum performance. Typically, flow separation is studied under sea-level conditions. However, this disregards the change of the ambient density during ascent of a launcher. The ambient flow properties are an important factor concerning the design of altitude-adaptive rocket nozzles like the dual bell nozzle. For this reason an experimental study was carried out to study the influence of the ambient density on flow separation within conventional nozzles.

  12. Troubleshooting vacuum systems steam turbine surface condensers and refinery vacuum towers

    CERN Document Server

    Lieberman, Norman P

    2012-01-01

    Vacuum systems are in wide spread use in the petrochemical plants, petroleum refineries and power generation plants. The existing texts on this subject are theoretical in nature and only deal with how the equipment functions when in good mechanical conditions, from the viewpoint of the equipment vendor.  In this much-anticipated volume, one of the most well-respected and prolific process engineers in the world takes on troubleshooting vacuum systems, and especially steam ejectors, an extremely complex and difficult subject that greatly effects the profitability of the majority of the world'

  13. In-Season High-Intensity Interval Training Improves Conditioning In High School Soccer Players.

    Science.gov (United States)

    Howard, Neal; Stavrianeas, Stasinos

    2017-01-01

    Soccer is characterized by high aerobic demands interspersed with frequent bursts of anaerobic activity. High-intensity interval training (HIIT) is considered a viable alternative to traditional endurance conditioning and offers the additional time-saving benefits of anaerobic training. We hypothesized that HIIT will compare favorably to traditional (aerobic-based) soccer conditioning over the course of a high school soccer season. Junior varsity soccer players were split into control (CON, n=16) and experimental (HIIT, n=16) groups for the 10-week study. The HIIT group performed 4-6 "all-out" sprints lasting 30s each, with 4.5 minute recovery, 3 times a week. The CON group performed endurance running for the same duration. The groups did not differ in any other aspect of their training. Participants completed the Yo-Yo intermittent recovery test level 1 (IR1), a 40-yard dash, vertical jump, Illinois agility test, and a sit-and-reach test, in two different testing sessions (pre/post season). Both HIIT and CON groups exhibited significant increase in IR1 test performance with time (741.6±307.6m vs. 1067.6±356.8m, ptraining.

  14. Microminiature thermionic vacuum flat panel display prototype

    Energy Technology Data Exchange (ETDEWEB)

    Sadwick, L.P.; Baker, B.; Chen, C.C.; Petersen, R.; Johnson, S.; Hwu, R.J. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Electrical Engineering

    1996-12-31

    The authors report on the fabrication and electrical characteristics of low work microminiature thermionic vacuum (MTV) diodes for use in flat panel display applications. In this work advances in the technology and performance of a novel thermionic analog to field emission vacuum microelectronic emitters that will be referred to by the descriptive name microminiature thermionic vacuum (MTV) emitters will be presented. The salient feature of MTV emitter technology is the use of an air-bridge (suspended) filament that greatly reduces the thermal load and stress on the system. MTV devices can be fabricated using conventional semiconductor and micromachining processing techniques on any thermally stable, vacuum compatible substrate for which a high temperature stable insulating layer can be grown or deposited on. In addition, the small (micron to sub-micron) distances between the cathode and anode allow the possibility of intrinsic operation to high frequencies comparable to that of field emitters since these devices will not suffer from solid-state electron transport effects that limit the upper frequency of operation for all semiconductor devices.

  15. Suprathermal electrons in a vacuum spark discharge

    Energy Technology Data Exchange (ETDEWEB)

    Bashutin, O. A., E-mail: boa308@mail.ru; Savjolov, A. S., E-mail: savjolov@plasma.mephi.ru [National Research Nuclear University MEPhI (Russian Federation)

    2016-04-15

    Results of experiments on the detection of suprathermal electron beams in the plasma of a highcurrent low-inductance vacuum spark by means of space-resolved spectral X-ray polarimetry are presented. It is shown that the observed polarization of bremsstrahlung may be caused by an ~100-keV electron beam propagating along the discharge axis from the pinching region toward the anode. The influence of the discharge initiation conditions on the parameters of the generated electron beams is analyzed.

  16. Vacuum energy sequestering and graviton loops

    OpenAIRE

    Kaloper, Nemanja; Padilla, Antonio

    2017-01-01

    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  17. THERMOCOUPLE VACUUM GAUGE

    Science.gov (United States)

    Price, G.W.

    1954-08-01

    A protector device is described for use in controlling the pressure within a cyclotron. In particular, an electrical circuit functions to actuate a vacuum pump when a predetermined low pressure is reached and disconnect the pump when the pressure increases abcve a certain value. The principal feature of the control circuit lies in the use of a voltage divider network at the input to a relay control tube comprising two parallel, adjustable resistances wherein one resistor is switched into the circuit when the relay connects the pump to a power source. With this arrangement the relay is energized at one input level received from a sensing element within the cyclotron chamber and is de-energized when a second input level, representing the higher pressure limit, is reached.

  18. Western Grid Can Handle High Renewables in Challenging Conditions

    Energy Technology Data Exchange (ETDEWEB)

    2015-11-01

    Fact sheet outlining the key findings of Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3). NREL and GE find that with good system planning, sound engineering practices, and commercially available technologies, the Western grid can maintain reliability and stability during the crucial first minute after grid disturbances with high penetrations of wind and solar power.

  19. INTELLIGENT TOOL CONDITION MONITORING IN HIGH-SPEED ...

    African Journals Online (AJOL)

    MR PRINCE

    rate, and depth of cut), and cutting force and spindle power were used in isolation or in combi- nation as input dataset in training the neural network to predict wear ... Modern manufacturing technologies are con- tinually tending towards automation of the pro- duction process due to increasing demand for high productivity.

  20. Primary Crystallization of High Chromium Cast Steel in Metastable Conditions

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2012-12-01

    Full Text Available The analysis of the primary crystallization of wear corrosive-erosive high chromium cast steel was introduced in the article on the basis of investigations the widened method of the differential thermal analysis with testers DTA-C and DTA-Is. The use of these testers enabled the analysis of crystallization for the various rates of cooling.

  1. Adapting high-rate anaerobic treatment to Middle East conditions

    NARCIS (Netherlands)

    Mahmoud, N.A.; Zeeman, G.; Lier, van J.B.

    2008-01-01

    High-rate anaerobic technologies offer cost-effective solutions for sewage treatment in the Middle East and Palestine in particular. The sewage characteristics in Palestine are quite different from the values elsewhere and show solids contents of more than 1000 mg chemical oxygen demand (COD)ss/L

  2. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  3. Abdominal intrauterine vacuum aspiration.

    Science.gov (United States)

    Tjalma, W A A

    2014-01-01

    Evaluating and "cleaning" of the uterine cavity is probably the most performed operation in women. It is done for several reasons: abortion, evaluation of irregular bleeding in premenopausal period, and postmenopausal bleeding. Abortion is undoubtedly the number one procedure with more than 44 million pregnancies terminated every year. This procedure should not be underestimated and a careful preoperative evaluation is needed. Ideally a sensitive pregnancy test should be done together with an ultrasound in order to confirm a uterine pregnancy, excluding extra-uterine pregnancy, and to detect genital and/or uterine malformations. Three out of four abortions are performed by surgical methods. Surgical methods include a sharp, blunt, and suction curettage. Suction curettage or vacuum aspiration is the preferred method. Despite the fact that it is a relative safe procedure with major complications in less than one percent of cases, it is still responsible for 13% of all maternal deaths. All the figures have not declined in the last decade. Trauma, perforation, and bleeding are a danger triage. When there is a perforation, a laparoscopy should be performed immediately, in order to detect intra-abdominal lacerations and bleeding. The bleeding should be stopped as soon as possible in order to not destabilize the patient. When there is a perforation in the uterus, this "entrance" can be used to perform the curettage. This is particularly useful if there is trauma of the isthmus and uterine wall, and it is difficult to identify the uterine canal. A curettage is a frequent performed procedure, which should not be underestimated. If there is a perforation in the uterus, then this opening can safely be used for vacuum aspiration.

  4. ULTRARAPID VACUUM-MICROWAVE HISTOPROCESSING

    NARCIS (Netherlands)

    KOK, LP; BOON, ME

    A novel histoprocessing method for paraffin sections is presented in which the combination of vacuum and microwave exposure is the key element. By exploiting the decrease in boiling temperature under vacuum, the liquid molecules in the tissues have been successfully extracted and exchanged at

  5. Vacuum Technology for Superconducting Devices

    CERN Document Server

    Chiggiato, P

    2014-01-01

    The basic notions of vacuum technology for superconducting applications are presented, with an emphasis on mass and heat transport in free molecular regimes. The working principles and practical details of turbomolecular pumps and cryopumps are introduced. The specific case of the Large Hadron Collider’s cryogenic vacuum system is briefly reviewed.

  6. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    Energy Technology Data Exchange (ETDEWEB)

    Niemi, K.; O' Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l' Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

    2013-07-15

    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

  7. Ideal Menu and Boil Conditions for High Content Amilose Rice

    OpenAIRE

    坂井,堅太郎; 山内,真知子; 水羽,陽子; 清水池,綾子; 鉄穴森,陽子; 谷廣,佳奈子; 高松,寛子; 井原,久美; 井上, 明美; 中西,弘子; 谷田,真奈美; 出戸,綾子; 普家,由香理; 高橋,恵里; 渡邉,奈奈

    2007-01-01

    Dietetic therapy is a primary base for diabetes mellitus, therefore food items should be selected for the patients with this disease to control blood glucose level, which lightens the burden of the other medical treatment they need. High amilose content rice is an ideal food to supply carbohydrate as nutrient for the patients with diabetes mellitus, based on our recent research showing moderate increase of blood glucose level after eating cooked rice with this race in human and ra...

  8. Flow Visualization Proposed for Vacuum Cleaner Nozzle Designs

    Science.gov (United States)

    2005-01-01

    In 1995, the NASA Lewis Research Center and the Kirby Company (a major vacuum cleaner company) began negotiations for a Space Act Agreement to conduct research, technology development, and testing involving the flow behavior of airborne particulate flow behavior. Through these research efforts, we hope to identify ways to improve suction, flow rate, and surface agitation characteristics of nozzles used in vacuum cleaner nozzles. We plan to apply an advanced visualization technology, known as Stereoscopic Imaging Velocimetry (SIV), to a Kirby G-4 vacuum cleaner. Resultant data will be analyzed with a high-speed digital motion analysis system. We also plan to evaluate alternative vacuum cleaner nozzle designs. The overall goal of this project is to quantify both velocity fields and particle trajectories throughout the vacuum cleaner nozzle to optimize its "cleanability"--its ability to disturb and remove embedded dirt and other particulates from carpeting or hard surfaces. Reference

  9. Vacuum Control Systems of the Cyclotrons in VECC, Kolkata

    Science.gov (United States)

    Roy, Anindya; Akhtar, Javed; Yadav, R. C.; Bhole, R. B.; Pal, Sarbajit; Sarkar, D.; Bhandari, R. K.

    2012-11-01

    VECC has undertaken the modernization of the K-130 Room Temperature Cyclotron (RTC) (operational since 1978) and commissioning of K-500 Superconducting Cyclotron (SCC) at present. The control system of RTC vacuum system has been upgraded to Programmable Logic Controller (PLC) based automated system from relay based manual system. A distributed PLC based system is under installation for SCC vacuum system. The requirement of high vacuum in both the cyclotrons (1×10-6 mbar for RTC and 5 × 10-8 mbar SCC) imposes the reliable local and remote operation of all vacuum components and instrumentation. The design and development of the vacuum control system of two cyclotrons using the Experimental Physics and Industrial Control System (EPICS) distributed real-time software tools are presented.

  10. High Performance Palladium Supported on Nanoporous Carbon under Anhydrous Condition

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Xu, Guodong

    2016-11-01

    Due to the high cost of polymer electrolyte fuel cells (PEFCs), replacing platinum (Pt) with some inexpensive metal was carried out. Here, we deposited palladium nanoparticles (Pd-NPs) on nanoporous carbon (NC) after wrapping by poly[2,2‧-(2,6-pyridine)-5,5‧-bibenzimidazole] (PyPBI) doped with phosphoric acid (PA) and the Pd-NPs size was successfully controlled by varying the weight ratio between Pd precursor and carbon support doped with PA. The membrane electrode assembly (MEA) fabricated from the optimized electrocatalyst with 0.05 mgPd cm-2 for both anode and cathode sides showed a power density of 76 mW cm-2 under 120 °C without any humidification, which was comparable to the commercial CB/Pt, 89 mW cm-2 with 0.45 mgPt cm-2 loaded in both anode and cathode. Meanwhile, the power density of hybrid MEA with 0.45 mgPt cm-2 in cathode and 0.05 mgPd cm-2 in anode reached 188 mW cm-2. The high performance of the Pt-free electrocatalyst was attributed to the porous structure enhancing the gas diffusion and the PyPBI-PA facilitating the proton conductivity in catalyst layer. Meanwhile, the durability of Pd electrocatalyst was enhanced by coating with acidic polymer. The newly fabricated Pt-free electrocatalyst is extremely promising for reducing the cost in the high-temperature PEFCs.

  11. Relaxation of vacuum energy in q-theory

    Science.gov (United States)

    Klinkhamer, F. R.; Savelainen, M.; Volovik, G. E.

    2017-08-01

    The q-theory formalism aims to describe the thermodynamics and dynamics of the deep quantum vacuum. The thermodynamics leads to an exact cancellation of the quantum-field zero-point-energies in equilibrium, which partly solves the main cosmological constant problem. But, with reversible dynamics, the spatially flat Friedmann-Robertson-Walker universe asymptotically approaches the Minkowski vacuum only if the Big Bang already started out in an initial equilibrium state. Here, we extend q-theory by introducing dissipation from irreversible processes. Neglecting the possible instability of a de-Sitter vacuum, we obtain different scenarios with either a de-Sitter asymptote or collapse to a final singularity. The Minkowski asymptote still requires fine-tuning of the initial conditions. This suggests that, within the q-theory approach, the decay of the de-Sitter vacuum is a necessary condition for the dynamical solution of the cosmological constant problem.

  12. High temperature integrated ultrasonic transducers for engine condition monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M.; Jen, C.K. [National Research Council of Canada, Boucherville, PQ (Canada). Industrial Materials Inst.; Wu, K.T. [McGill Univ., Montreal, PQ (Canada). Dept. of Electrical and Computer Engineering; Bird, J.; Galeote, B. [National Research Council of Canada, Ottawa, ON (Canada). Inst. for Aerospace Research; Mrad, N. [Department of National Defence, Ottawa, ON (Canada). Air Vehicles Research Station

    2009-07-01

    Piezoelectric ultrasonic transducers (UTs) are used for real-time, in-situ or off-line nondestructive evaluation (NDE) of large metallic structures such as airplanes, automobiles, ships, pressure vessels and pipelines because of their subsurface inspection capability, fast inspection speed, simplicity and cost-effectiveness. The objective of this study was to develop and evaluate effective integrated ultrasonic transducers (IUT) technology to perform non-intrusive engine NDE and structural health monitoring (SHM). High temperature IUTs made of bismuth titanate piezoelectric film greater than 50 {mu}m in thickness were coated directly onto a modified CF700 turbojet engine outer casing, oil sump and supply lines and gaskets using sol-gel spray technology. The assessment was limited to temperatures up to 500 degrees C. The center frequencies of the IUTs were approximately 10 to 17 MHz. Ultrasonic signals obtained in pulse/echo measurements were excellent. High temperature ultrasonic performance will likely be obtained in the transmission mode as well. The potential applications of the developed IUTs include non-intrusive real-time temperature, lubricant oil quality and metal debris monitoring within a turbojet engine environment. 9 refs., 13 figs.

  13. Versatile Design Strategy for Highly Luminescent Vacuum-Evaporable and Solution-Processable Tridentate Gold(III) Complexes with Monoaryl Auxiliary Ligands and Their Applications for Phosphorescent Organic Light Emitting Devices.

    Science.gov (United States)

    Tang, Man-Chung; Lee, Chin-Ho; Lai, Shiu-Lun; Ng, Maggie; Chan, Mei-Yee; Yam, Vivian Wing-Wah

    2017-07-12

    A new class of brightly blue-green-emitting arylgold(III) complexes has been synthesized, characterized, and applied as phosphorescent dopants in the fabrication of solution-processable and vacuum-deposited organic light-emitting devices (OLEDs). These arylgold(III) complexes can be readily synthesized by reacting the corresponding arylboronic acids with the gold(III) precursor complexes in a one-pot Suzuki-Miyaura coupling reaction. When compared to the structurally related alkynylgold(III) complex, arylgold(III) complexes 1 and 2 exhibit much higher photoluminescence quantum yields in solution state. High photoluminescence quantum yields are also observed in solid-state thin films. More importantly, the solid-state emission spectra show strong resemblance to those in solution, irrespective of the dopant concentration, leading to significant improvement in the color purity of the OLEDs by suppressing any excimer emission resulting from the π-stacking of the tridentate ligand. High performance solution-processable and vacuum-deposited blue-green-emitting OLEDs have also been realized, with maximum external quantum efficiencies of 7.3% and 14.7%, respectively, representing the first demonstration of efficient blue-green-emitting OLEDs based on cyclometalated arylgold(III) complexes.

  14. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake systems...

  15. The HIE-ISOLDE Vacuum System

    CERN Document Server

    Vandoni, G; Radwan, K; Chiggiato, P

    2014-01-01

    The High Intensity and Energy Isolde (HIE-Isolde) project aims at increasing the energy and intensity of the radioactive ion beams (RIB) delivered by the present Rex-Isolde facility. Energy up to 10MeV/amu will be reached by a new post-accelerating, superconducting (SC) linac. Beam will be delivered via a HEBT to three experimental stations for nuclear physics. To keep the SC linac compact and avoid cold-warm transitions, the cryomodules feature a common beam and insulation vacuum. Radioactive ion beams require a hermetically sealed vacuum, with transfer of the effluents to the nuclear ventilation chimney. Hermetically sealed, dry, gas transfer vacuum pumps are preferred to gas binding pumps, for an optimized management of radioactive contamination risk during maintenance and intervention. The vacuum system of the SC-linac is isolated by two fast valves, triggered by fast reacting cold cathode gauges installed on the warm linac, the HEBT and the experimental stations. Rough pumping is distributed, while the H...

  16. Diffusion Creep of Enstatite at High Pressures Under Hydrous Conditions

    Science.gov (United States)

    Zhang, Guinan; Mei, Shenghua; Song, Maoshuang; Kohlstedt, David L.

    2017-10-01

    Mantle convection and large-scale plate motion depend critically on the nature of the lithosphere-asthenosphere boundary and thus on the viscosity structure of Earth's upper mantle, which is determined by the rheological properties of its constituent minerals. To constrain the flow behavior of orthopyroxene, the second most abundant constituent of the upper mantle, deformation experiments were carried out in triaxial compressive creep on fine-grained ( 6 μm) samples of enstatite at high pressures (3.8-6.3 GPa) and high temperatures (1323-1573 K) using a deformation-DIA apparatus. Based on results from this study, the deformation behavior of enstatite is quantitatively presented in the form of a flow law that describes the dependence of deformation rate on differential stress, water fugacity, temperature, and pressure. Specifically, the creep rate depends approximately linearly on stress, indicating deformation in the diffusion creep regime. A least squares regression fit to our data yielded a flow law for diffusion creep with an activation energy of 200 kJ/mol and an activation volume of 14 × 10-6 m3/mol. The magnitude of the water-weakening effect is similar to that for olivine with a water fugacity exponent of r ≈ 0.7. This strong dependence of viscosity on water fugacity (concentration) indicates that the viscosity of an orthopyroxene-bearing mantle varies from one geological setting to another, depending on the large-scale water distribution. Based on the rheology contrast between olivine and enstatite, we conclude that olivine is weaker than enstatite throughout most of the upper mantle except in some shallow regions in the diffusion creep regime.

  17. Numerical modeling and validation of squeezed-film damping in vacuum-packaged industrial MEMS

    Science.gov (United States)

    Syed, Wajih U.; Brimmo, Ayoola; Waheed, Owais; Bojesomo, Alabi; Hassan Ali, Mohamed; Ocak, Ilker; Chengliang, Sun; Chatterjee, Aveek; Elfadel, Ibrahim (Abe M.

    2017-07-01

    Several high-performance, industrial micro-electromechanical (MEM) devices, such as gyroscopes, magnetometers, high-Q resonators and piezoelectric energy harvesters, require wafer bonding and packaging under near-vacuum conditions. One very challenging aspect of the design, verification and characterisation of these devices is to predict their performance characteristics in the presence of any residual gases post-packaging. Such gases contribute to the energy losses resulting from device surfaces squeezing or sliding against the gas films within the device cavities. In this paper, we fully expose the modelling assumptions used in commercial FEM tools to estimate the squeezed-film damping (SFD) experienced by MEM devices that are packaged under near-vacuum conditions. We also explain the various meshing options to enable the extraction of the most accurate Q factors under existing SFD assumptions. In addition, we compare the computational results across a variety of commercial FEM codes against measurements obtained under realistic vacuum conditions for an industrial high-Q magnetometer. These measurements suggest that existing computational models may deviate by as much as 25% on Q factor values for gas flow regimes under operating cavity pressures of less than 1 Torr.

  18. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da Silva, F.; Lange, E. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Institut de Chimie-Bât. B6C, Université de Liège, B-4000 Liège 1 (Belgium); Brunger, M. J., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); and others

    2015-10-14

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  19. Vacuum-Ultraviolet Photovoltaic Detector.

    Science.gov (United States)

    Zheng, Wei; Lin, Richeng; Ran, Junxue; Zhang, Zhaojun; Ji, Xu; Huang, Feng

    2018-01-23

    Over the past two decades, solar- and astrophysicists and material scientists have been researching and developing new-generation semiconductor-based vacuum ultraviolet (VUV) detectors with low power consumption and small size for replacing traditional heavy and high-energy-consuming microchannel-detection systems, to study the formation and evolution of stars. However, the most desirable semiconductor-based VUV photovoltaic detector capable of achieving zero power consumption has not yet been achieved. With high-crystallinity multistep epitaxial grown AlN as a VUV-absorbing layer for photogenerated carriers and p-type graphene (with unexpected VUV transmittance >96%) as a transparent electrode to collect excited holes, we constructed a heterojunction device with photovoltaic detection for VUV light. The device exhibits an encouraging VUV photoresponse, high external quantum efficiency (EQE) and extremely fast tempera response (80 ns, 10 4 -10 6 times faster than that of the currently reported VUV photoconductive devices). This work has provided an idea for developing zero power consumption and integrated VUV photovoltaic detectors with ultrafast and high-sensitivity VUV detection capability, which not only allows future spacecraft to operate with longer service time and lower launching cost but also ensures an ultrafast evolution of interstellar objects.

  20. Synoptic conditions leading to extremely high temperatures in Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, R.; Prieto, L.; Hernandez, E.; Teso, T. del [Dept. Fisica de la Tierra II, Fac. CC. Fisicas, Univ. Camplutense de Madrid (Spain); Diaz, J. [Centro Universitario de Salud Publica, Univ. Autonoma de Madrid (Spain)

    2002-02-01

    Extremely hot days (EHD) in Madrid have been analysed to determine the synoptic patterns that produce EHDs during the period of 1955-1998. An EHD is defined as a day with maximum temperature higher than 36.5 C, a value which is the threshold for the intense effects on mortatility and it coincides with the 95 percentile of the series. Two different situations have been detected as being responsible for an EHD occurrence, one more dynamical, produced by southern fluxes, and another associated with a stagnation situation over Iberia of a longer duration. Both account for 92% of the total number of days, thus providing an efficient classification framework. A circulation index has been derived to characterise and forecast an EHD occurrence. This paper shows that EHD occur in Madrid during short duration events, and no long heat waves, like those recorded in other cities, are present. Additionally, no clear pattern can be detected in the EHD frequency; the occurrence is tied to changes in the summer location of the Azores high. (orig.)

  1. Engine Oil Condition Monitoring Using High Temperature Integrated Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Jeff Bird

    2011-01-01

    Full Text Available The present work contains two parts. In the first part, high temperature integrated ultrasonic transducers (IUTs made of thick piezoelectric composite films, were coated directly onto lubricant oil supply and sump lines of a modified CF700 turbojet engine. These piezoelectric films were fabricated using a sol-gel spray technology. By operating these IUTs in transmission mode, the amplitude and velocity of transmitted ultrasonic waves across the flow channel of the lubricant oil in supply and sump lines were measured during engine operation. Results have shown that the amplitude of the ultrasonic waves is sensitive to the presence of air bubbles in the oil and that the ultrasound velocity is linearly dependent on oil temperature. In the second part of the work, the sensitivity of ultrasound to engine lubricant oil degradation was investigated by using an ultrasonically equipped and thermally-controlled laboratory testing cell and lubricant oils of different grades. The results have shown that at a given temperature, ultrasound velocity decreases with a decrease in oil viscosity. Based on the results obtained in both parts of the study, ultrasound velocity measurement is proposed for monitoring oil degradation and transient oil temperature variation, whereas ultrasound amplitude measurement is proposed for monitoring air bubble content.

  2. Application of vacuum technology: Vacuum insulated glazing- improving the energy efficiency of buildings

    OpenAIRE

    Memon, S.

    2014-01-01

    Heat loss through the windows of buildings is one of the factors contributing to high energy consumption for space heating resulting in excessive CO2 emissions which lead to climate change. Replacing standard double air filled glazing, U value of 2.85 Wm-2K-1, with vacuum insulated glazing, U value of approximately 0.8 Wm-2K-1, reduces the heat loss by more than three times and reduces the frame thickness due to the thinness of vacuum insulated glazing (8.15mm) as illustrated in Fig.1. Furthe...

  3. Experimental tests of vacuum energy

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    While the current vacuum energy of the Universe is very small, in our standard cosmological picture it has been much larger at earlier epochs. We try to address the question of what are possible ways to try to experimentally verify this. One direction is to look for systems where vacuum energy constitutes a non-negligible fraction of the total energy, and study the properties of those. Another possibility is to focus on the epochs around cosmic phase transitions, when the vacuum energy is of the same order as the total energy. Along these lines we investigate properties of neutron stars and the imprint of phase transitions on primordial gravitational waves.

  4. Versatile high-repetition-rate phase-locked chopper system for fast timing experiments in the vacuum ultraviolet and x-ray spectral region.

    Science.gov (United States)

    Plogmaker, Stefan; Linusson, Per; Eland, John H D; Baker, Neville; Johansson, Erik M J; Rensmo, Håkan; Feifel, Raimund; Siegbahn, Hans

    2012-01-01

    A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of ~8 to ~120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses or pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.

  5. Versatile high-repetition-rate phase-locked chopper system for fast timing experiments in the vacuum ultraviolet and x-ray spectral region

    Energy Technology Data Exchange (ETDEWEB)

    Plogmaker, Stefan; Johansson, Erik M. J.; Rensmo, Haakan; Feifel, Raimund; Siegbahn, Hans [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Linusson, Per [Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm (Sweden); Eland, John H. D. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ (United Kingdom); Baker, Neville [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ (United Kingdom)

    2012-01-15

    A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of {approx}8 to {approx}120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses or pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.

  6. Thermodynamic modelling of phase equilibrium in system Ti-B-Si-C, synthesis and phases composition of borides and carbides layers on titanic alloyVT-1 at electron beam treatment in vacuum

    Science.gov (United States)

    Smirnyagina, N. N.; Khaltanova, V. M.; Lapina, A. E.; Dasheev, D. E.

    2017-01-01

    Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VT-1 are generated at diffused saturation in vacuum. Formation in a composite of MAX phase Ti3SiC2 is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.

  7. A modified pump-out technique used for fabrication of low temperature metal sealed vacuum glazing

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jun Fu; Hyde, Trevor J.; Fang, Yueping [Center for Sustainable Technologies, School of the Built Environment, University of Ulster, Newtownabbey, Co. Antrim BT37 0QB, Northern Ireland (United Kingdom); Eames, Philip C.; Wang, Jinlei [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2007-09-15

    A modified pump-out technique, incorporating a novel pump-out hole sealing process, has been developed that enables a high level of vacuum to be achieved between the panes of a vacuum glazing. The modified pump-out method provides several potential opportunities for the fabrication of a vacuum glazing with improved thermal performance. In particular, improved flexibility for production of a wide range of glazing sizes may allow a lower cost of manufacture to be achieved by avoiding the expense of a high vacuum oven which would otherwise be required for commercial production of high performance, large-scale vacuum glazings. The thermal performance of the vacuum glazing fabricated using the pump-out technique was characterized using a guarded hotbox calorimeter and theoretically analyzed using a finite volume model. The excellent experimentally determined thermal performance of the fabricated vacuum glazing was in good agreement with that predicted theoretically. (author)

  8. The potential of vacuum therapy in the treatment of a newborn infant with severe thermal injury

    Directory of Open Access Journals (Sweden)

    L. I. Budkevich

    2015-01-01

    Full Text Available The paper describes a clinical case of successful combination therapy in a newborn infant with severe thermal injury. When admitted to the hospital, the infant was diagnosed with third-degree flame burn covering 75% of the body surface and shock. Specialized emergency care involved antishock measures and replacement of vital functions, stepwise surgical interventions aimed to excise necrotic tissues and to restore lost skin tissue, and antimicrobial and symptomatic therapies. Topical treatment included the use of current wound coatings. Skin autocells were used for significant skin defect. Aacuum therapy was performed to stimulate repair processes and to prepare wounds for further skin plasty. The techniques of vacuum therapy included RENAS\\S-GO and PICO apparatuses. Its efficiency was evaluated by microbiological, immunohistochemical, and planimetric examinations. Analysis of the decontaminating impact of a vacuum coating could establish its substantial effect in reducing wound bacterial contamination by 65% in the study group and by an average of 21% in the comparison group. That of immunohistochemical findings during vacuum therapy could reveal the high expression of two markers characterizing wound an-giogenesis. Comparative analysis of planimetric readings showed no significant differences in the use of vacuum therapy and current wound coatings. Thus, negative-pressure therapy creates favorable conditions for a wound healing process, providing effective wound decontamination and stimulating granulation tissue maturation as a factor to prepare for skin plasty.

  9. Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

    Science.gov (United States)

    Penry, J F; Upton, J; Mein, G A; Rasmussen, M D; Ohnstad, I; Thompson, P D; Reinemann, D J

    2017-01-01

    The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece

  10. Alumina barrier for vacuum brazing

    Science.gov (United States)

    Beuyukian, C. S.

    1980-01-01

    Heating platens of vacuum-brazing press will not stick to workpiece if aluminum oxide "paper" is interposed. Paper does not disintegrate in press, will not contaminate braze alloy, and helps form smoothly contoured, regular fillet at brazed edges.

  11. SILICON REFINING BY VACUUM TREATMENT

    Directory of Open Access Journals (Sweden)

    André Alexandrino Lotto

    2014-12-01

    Full Text Available This work aims to investigate the phosphorus removal by vacuum from metallurgical grade silicon (MGSi (98.5% to 99% Si. Melting experiments were carried out in a vacuum induction furnace, varying parameters such as temperature, time and relation area exposed to the vacuum / volume of molten silicon. The results of chemical analysis were obtained by inductively coupled plasma (ICP, and evaluated based on thermodynamic and kinetic aspects of the reaction of vaporization of the phosphorus in the silicon. The phosphorus was decreased from 33 to approximately 1.5 ppm after three hours of vacuum treatment, concluding that the evaporation step is the controlling step of the process for parameters of temperature, pressure and agitation used and refining by this process is technically feasible.

  12. 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.

  13. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    To minimize eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical stength, it was corrugated in a hydro-forming process. The chamber is curved, to follow the beam's orbital path. Under vacuum, the chamber tends to staighten, the ceramic spacer along half of its length keeps it in place (see also 7402458).

  14. Rugged Preheaters For Vacuum Plasma Spraying

    Science.gov (United States)

    Woodford, William H.; Mckechnie, Timothy N.; Sander, Lewis D.; Power, Christopher A.; Sander, Heather L.; Nguyen, Dalton D.

    1994-01-01

    Electric preheater units built to ensure large workpieces to be coated with metals by vacuum plasma spraying heated uniformly to requisite high temperatures by time plasma torch arrives. Units similar to electrical-resistance ribbon heaters in toasters and in some small portable electric "space" heaters. Nichrome resistance-heating ribbons wrapped around ceramic insulating spools on rings and on plates. Round workpiece placed in middle of ring preheater. Plate preheaters stacked as needed near workpiece.

  15. Fabricate-On-Demand Vacuum Insulating Glazings

    Energy Technology Data Exchange (ETDEWEB)

    McCamy, James W. [PPG Industries, Inc., Pittsburgh, PA (United States)

    2017-09-19

    PPG proposed to design a fabricate-on-demand manufacturing process to overcome the cost and supply chain issues preventing widespread adoption of vacuum insulated glazing (VIG) units. To do so, we focused on improving three areas of VIG manufacturing that drive high costs and limit the ability for smaller manufacturers to enter the market: edge sealing, pillar design/placement, and evacuating the VIG.

  16. Energy Performance Assessment of a 2nd-Generation Vacuum Double Glazing Depending on Vacuum Layer Position and Building Type in South Korea

    OpenAIRE

    Seung-Chul Kim; Jong-Ho Yoon; Ru-Da Lee

    2017-01-01

    (1) Background: The application of high insulation to a building envelope helps reduce the heating load, but increases the cooling load. Evaluating the installation of high insulation glazing to buildings in climate zones with four distinct seasons, as in the case of South Korea, is very important; (2) Methods: This study compared the heating energy performance of four types of glazing, inside vacuum double glazing, outside vacuum double glazing, single vacuum glazing, and low-e double glazin...

  17. Soot measurements for diesel and biodiesel spray combustion under high temperature highly diluted ambient conditions

    KAUST Repository

    Zhang, Ji

    2014-11-01

    This paper presents the soot temperature and KL factor for biodiesel, namely fatty acid methyl ester (FAME) and diesel fuel combustion in a constant volume chamber using a two-color technique. The KL factor is a parameter for soot concentration, where K is an absorption coefficient and proportional to the number density of soot particles, L is the geometric thickness of the flame along the optical detection axis, and KL factor is proportional to soot volume fraction. The main objective is to explore a combustion regime called high-temperature and highly-diluted combustion (HTHDC) and compare it with the conventional and low-temperature combustion (LTC) modes. The three different combustion regimes are implemented under different ambient temperatures (800 K, 1000 K, and 1400 K) and ambient oxygen concentrations (10%, 15%, and 21%). Results are presented in terms of soot temperature and KL factor images, time-resolved pixel-averaged soot temperature, KL factor, and spatially integrated KL factor over the soot area. The time-averaged results for these three regimes are compared for both diesel and biodiesel fuels. Results show complex combined effects of the ambient temperature and oxygen concentration, and that two-color temperature for the HTHDC mode at the 10% oxygen level can actually be lower than the conventional mode. Increasing ambient oxygen and temperature increases soot temperature. Diesel fuel results in higher soot temperature than biodiesel for all three regimes. Results also show that diesel and biodiesel fuels have very different burning and sooting behavior under the three different combustion regimes. For diesel fuel, the HTHDC regime offers better results in terms of lower soot than the conventional and LTC regimes, and the 10% O2, 1400 K ambient condition shows the lowest soot concentration while maintaining a moderate two-color temperature. For biodiesel, the 15% O2, 800 K ambient condition shows some advantages in terms of reducing soot

  18. Brazing vacuum ceramic tubes for magnets applications

    Energy Technology Data Exchange (ETDEWEB)

    Bagnato, O.R.; Francisco, R.F. [Laboratorio Nacional de Luz Sincrotron (LNLS), SP (Brazil); Gobbi, A.L. [Laboratorio Nacional de Nanotecbologia (LNNano), SP (Brazil); Falvo, T. [Engecer Ltda, Sao Carlos, SP (Brazil)

    2014-07-01

    Full text: The Sirius Project is an initiative of the Brazilian Synchrotron Light Laboratory - LNLS (CNPEM - MCTI ), for the design, construction and operation of a new synchrotron radiation source 3rd generation, with high brightness and energy of the electrons of 3. 0 GeV. Among many other components, will be built 80 ceramic cameras embedded in specials magnets, whose function is to act to correct the orbit of the electron beam in the storage ring. The ceramic chamber is crucial for this application because this material is transparent to the magnetic field generated in the electro magnet and thus acts directly on the electron beam. The difficulty of these constructive components lies in the fact that, the ceramic components must be attached to metal components will join vacuum chambers that make up the ring, and then must present excellent mechanical and vacuum tight. The process of chemical bonding between the ceramic and metal components is performed by brazing in high vacuum. After brazing, is deposited a film of copper with 7 micrometers thickness. The objective of this paper is to describe the process of film deposition and brazing of copper and the excellent results obtained in the production, mechanical characterization, microstructural and tightness. The results obtained with the process indicate an homogeneous film with high adhesion and electrical resistance near the estimated values??. Tests are being carried out by XPS and SEM techniques for chemical and structural characterization. (author)

  19. Vacuum-assisted cesarean section

    Directory of Open Access Journals (Sweden)

    McQuivey RW

    2017-03-01

    Full Text Available Ross W McQuivey,1 Jon E Block2 1Clinical Innovations, Salt Lake City, UT, 2Independent consultant, San Francisco, CA, USA Abstract: There has been a dramatic rise in the frequency of cesarean sections, surpassing 30% of all deliveries in the US. This upsurge, coupled with a decreasing willingness to allow vaginal birth after cesarean section, has resulted in an expansion of the use of vacuum assistance to safely extract the fetal head. By avoiding the use of a delivering hand or forceps blade, the volume being delivered through the uterine incision can be decreased when the vacuum is used properly. Reducing uterine extensions with their associated complications (eg, excessive blood loss in difficult cases is also a theoretical advantage of vacuum delivery. Maternal discomfort related to excessive fundal pressure may also be lessened. To minimize the risk of neonatal morbidity, proper cup placement over the “flexion point” remains essential to maintain vacuum integrity and reduce the chance of inadvertent detachment and uterine extensions. Based on the published literature and pragmatic clinical experience, utilization of the vacuum device is a safe and effective technique to assist delivery during cesarean section. Keywords: cesarean section, vacuum, forceps, birth, delivery

  20. Assessment of penetration through vacuum cleaners and recommendation of wet cyclone technology.

    Science.gov (United States)

    Seo, Youngjin; Han, Taewon

    2013-04-01

    In many commercial vacuum cleaners, the captured aerosol particles contained in the dust collector may accidentally release from the exhaust filtration owing to leakage or penetration. Vacuum cleaners may cause dust to become airborne by exhausting air that is not completely filtered. This may cause the operator to inhale dust, in turn causing health problems. This study aimed to investigate the dust penetration rates from three commercial vacuum cleaners and suggest the best technique for completely filtering exhaust air using a combination of cyclonic separation and water filtration. The commercial vacuum cleaners were tested inside a custom-built hood, and the exhausted particles were monitored using a sampling probe in conjunction with an aerosol particle sizer Quartzose mineral dusts were added to each vacuum cleaner through the dust transport line. A 2400 L/min wet cyclone was employed as the proposed vacuum cleaner It was designed using Stokes scaling, and its collection characteristics were evaluated using polystyrene latex beads. Surprisingly, the conventional vacuum cleaners failed to capture an overall average of approximately 14% of the particles in the given size range. However, only approximately 3.8% of the collected particles escaped from the vacuum cleaner that used the wet cyclone technology. Thus, the proposed vacuum cleaner should potentially be an effective method for vacuuming household dust. The successful investigation of conventional vacuum cleaners is useful for both manufacturers and users. As an effective vacuum cleaning mechanism, household dust is able to migrate along the thin water, film that forms on the inner walls of the cyclone vacuum cleaner. It collects dust in a small water inflow (3 mL/min), which allows it to capture a higher percentage of contaminants than most of the currently available vacuum cleaners. The significantly low accidental exposure rates achieved by this new vacuum cleaner enable healthy conditions in various

  1. Vacuum Die Casting Process and Simulation for Manufacturing 0.8 mm-Thick Aluminum Plate with Four Maze Shapes

    Directory of Open Access Journals (Sweden)

    Chul Kyu Jin

    2015-02-01

    Full Text Available Using vacuum die casting, 0.8 mm-thick plates in complicated shapes are manufactured with the highly castable aluminum alloy Silafont-36 (AlSi9MgMn. The sizes and shapes of the cavities, made of thin plates, feature four different mazes. To investigate formability and mechanical properties by shot condition, a total of six parameters (melt temperatures of 730 °C and 710 °C; plunger speeds of 3.0 m/s and 2.5 m/s; vacuum pressure of 250 mbar and no vacuum are varied in experiments, and corresponding simulations are performed. Simulation results obtained through MAGMA software show similar tendencies to those of the experiments. When the melt pouring temperature is set to 730 °C rather than 710 °C, formability and mechanical properties are superior, and when the plunger speed is set to 3.0 m/s rather than to 2.5 m/s, a fine, even structure is obtained with better mechanical properties. The non-vacuumed sample is half unfilled. The tensile strength and elongation of the sample fabricated under a melt temperature of 730 °C, plunger speed of 3.0 m/s, and vacuum pressure of 250 mbar are 265 MPa and 8.5%, respectively.

  2. Development of self-aligned gated porous silicon microtip field emission arrays for vacuum microelectronic applications

    Science.gov (United States)

    Jessing, Jeffrey Richard

    Solid state microelectronics is the dominate technology in the present day electronics industry. However, as the physical dimensions decrease, it is becoming apparent that solid state devices have inherent performance limitations, such as finite saturation drift velocity, high temperature degradation, and failure in extreme radiation environments. To address these problems a relatively new technology, called vacuum microelectronics, has emerged. Vacuum microelectronics encompasses the fabrication, characterization, and application of various devices whose operation is based on vacuum ballistic transport of field emitted electrons from microminiature electrodes. The field of vacuum microelectronics has advanced at a rapid rate over the past decade; however, there remain key issues to be addressed prior to any widespread commercialization of this technology. Field emission arrays (FEAs) must operate at low voltages and generate high current densities with uniform, long-lifetime operation. The use of porous silicon cathodes in vacuum microelectronic applications is a promising alternative to existing silicon and metal field emitters. Surface modification of bulk crystalline silicon by electrochemical anodization in a concentrated hydrofluoric acid (HF) solution has been shown to produce large submicroscopic field enhancement and large emission area. The primary focus of this research was the development of novel gated FEAs based on porous silicon microtip cathodes. Device design consisted of both experimental and theoretical efforts. Employing semiconductor process technology, the successful fabrication of an operational self-aligned gated porous silicon microtip FEA was demonstrated. Small arrays exhibited Fowler-Nordheim characteristics over several decades of anode current. A peak stable current of approximately 60 to 70 nA per tip was obtained at less than 125 V. A correlation of anodization conditions with emission properties has been found, and a simple emission

  3. Mitigation of Radiation and EMI Effects on the Vacuum Control System of LHC

    CERN Document Server

    Pigny, G; Krakowski, P; Rio, B

    2014-01-01

    The 26 km of vacuum chambers where circulates the beam of the Large Hadron Collider (LHC) must be maintained under Ultra High Vacuum (UHV) to minimize the beam interactions with residual gases, and allow the operation of specific systems. The vacuum level is measured by several thousands of gauges along the accelerator. Bad vacuum quality may trigger a beam dump and close the associated sector valves. The effects of radiation or Electromagnetic Interferences (EMI) on components that may stop the machine must be evaluated and minimized. We report on the actions implemented to mitigate their impact on the vacuum control system.

  4. Oak Ridge TNS program: evaluation of a secondary vacuum enclosure for TNS

    Energy Technology Data Exchange (ETDEWEB)

    Sardella, C.

    1979-11-01

    This report investigates the use of a secondary vacuum enclosure (SVE) to eliminate the need for high vacuum joints between torus sectors and thereby improve device maintainability. Several conceptual SVE designs have been identified and evaluated and the vacuum building was selected as the most promising. A mechanically assembled torus having high impedance seals (rather than vacuum tight seals) between sectors is described and the mechanical characteristics of the device are discussed. The size of the vacuum pump system and the pumpdown time for the vacuum building were determined. Studied also were the many aspects of the effect a vacuum environment has on tokamak systems. The potential benefits of using a SVE on a commercial reactor were investigated and stated in terms of improved plant availability. (MOW)

  5. Achieving ultrahigh vacuum in an unbaked chamber with glow ...

    Indian Academy of Sciences (India)

    Glow discharge conditioning (GDC) has long been accepted as one of the basic wall conditioning techniques for achieving ultrahigh vacuum in an unbaked chamber. As a part of this fundamental experimental study, a test chamber has been fabricated from stainless steel 304 L with its inner surface electropolished on ...

  6. Characteristics of a miniature vacuum spark

    Science.gov (United States)

    Wong, C. S.; Ong, C. X.; Chin, O. H.; Lee, S.; Choi, P.

    1989-12-01

    The characteristics of a miniature vacuum spark device are investigated. It is powered by a 2-stage 50 kV Marx and operated without an external triggering source. Discharge initiation is effected by an electron beam produced by the Pseudospark effect behind the hollow cathode. For discharges performed in air at a pressure of below 10-2 mbar, intense X-ray is detected. Although this X-ray has been found to consist of predominantly the Fe-Kα line produced by the electron beam bombardment of the stainless steel anode, its high intensity, singly-pulsed short-duration temporal structure and nearly monochromatic spectrum make the present vacuum spark an ideal pulsed X-ray source for many applications. The device is also compact, low cost and easy to operate. As an example of its applications, the contact radiography of a living lizard has been obtained using this X-ray source.

  7. LHC Vacuum Upgrade during LS1

    CERN Document Server

    Jimenez, J M; 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 reengineering 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, th...

  8. Towards measuring the Archimedes force of vacuum

    CERN Document Server

    Calloni, Enrico; De Rosa, Rosario; Di Fiore, Luciano; Esposito, Giampiero; Garufi, Fabio; Rosa, Luigi; Rovelli, Carlo; Ruggi, Paolo; Tafuri, Francesco

    2014-01-01

    We discuss the force exerted by the gravitational field on a Casimir cavity in terms of Archimedes' force of vacuum, we identify the force that can be tested against observation and we show that the present technology makes it possible to perform the first experimental tests. We motivate the use of suitable high-Tc superconductors as modulators of Archimedes' force. We analyze the possibility of using gravitational wave interferometers as detectors of the force, transported through an optical spring from the Archimedes vacuum force apparatus to the gravitational interferometers test masses to maintain the two systems well separated. We also analyze the use of balances to actuate and detect the force, we compare different solutions and discuss the most important experimental issues.

  9. Impacts on Dissipative Sonic Vacuum

    Science.gov (United States)

    Xu, Yichao; Nesterenko, Vitali

    We investigate the propagating compression bell shape stress waves generated by the strikers with different masses impacting the sonic vacuum - the discrete dissipative strongly nonlinear metamaterial with zero long wave sound speed. The metamaterial is composed of alternating steel disks and Nitrile O-rings. Being a solid material, it has exceptionally low speed of the investigated stress waves in the range of 50 - 74 m/s, which is a few times smaller than the speed of sound or shock waves in air generated by blast. The shape of propagating stress waves was dramatically changed by the viscous dissipation. It prevented the incoming pulses from splitting into trains of solitary waves, a phenomenon characteristic of the non-dissipative strongly nonlinear discrete systems when the striker mass is larger than the cell mass. Both high-speed camera images and numerical simulations demonstrate the unusual rattling behavior of the top disk between the striker and the rest of the system. The linear momentum and energy from the striker were completely transferred to the metamaterial. This strongly nonlinear dissipative metamaterial can be designed for the optimal attenuation of dynamic loads generated by impact or contact explosion. Author 1 wants to acknowledge the support provided by UCSD.

  10. A Study of the Relationship between Building Conditions and Student Academic Achievement in Pennsylvania's High School

    OpenAIRE

    O'Sullivan, Sean

    2006-01-01

    This study investigated the relationship between school building conditions and student academic achievement in Pennsylvania's high schools. Research questions analyzed by step-wise multiple regression were: (a) Is there a relationship between overall school building conditions and student academic achievement in Pennsylvania's high schools when socio-economic status (SES) is held constant?; (b) Is there a relationship between the cosmetic conditions of school facilities and student academic ...

  11. The Isolation of Sitronellal and Rhodinol from Lemongrass Oil Using Vacuum Distillation Fractination

    Directory of Open Access Journals (Sweden)

    Fitriana Djafar

    2010-06-01

    Full Text Available The main componenet of lemongrass oil that is sitronellal and rhodinol (sitronellol and geraniol was isolated by using vacuum of distillation fraksinasi. Variably the research included the variable continue to, that is the sample weight (300 mL and process time (4 hours; and the variable changed, that is the pressure (80, 95 and 100 mbar and the temperature (145, 150, and 160o C. Results of the analysis of the ras material showed that lemongrass oil that came from Kota Panjang, Gayo Lues, Province Aceh had the content sitronellal that was high that is of 51.067% and rhodinol of 30.761%. The characteristics from lemongrass oil was yellow faded, the ray index 1.466, the specific gravity 0.889 solubility in alcohol 1:1 clear and the round of optics 19.15. The distillation sitronellal, 28.87% rhodinol (22.60% geraniol and 6.27% sitronellol and 11% other component. The condition for the process that was good enough in the isolation sitronellol used distillation vacuum of fraksinasi with the temperature and the pressure that were low that is 145o C and 80 mbar. The condition for the process that was quite good in the isolation rhodinol was use to use vacuum of distillation fraksinasi in the temperature and the pressure that were not too high and or low that is 150o C and 95 mbar.

  12. An investigation on 800 nm femtosecond laser ablation of K9 glass in air and vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shi-zhen, E-mail: xusz@uestc.edu.cn [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Yao, Cai-zhen [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Dou, Hong-qiang [Department of Material Science and Engineering, Sichuan Engineering Technical College, Deyang 618000 (China); Liao, Wei, E-mail: liaowei@caep.cn [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Li, Xiao-yang; Ding, Ren-jie [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Zhang, Li-juan; Liu, Hao; Yuan, Xiao-dong [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Zu, Xiao-tao [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2017-06-01

    Highlights: • The fs laser ablation of borosilicate glass (K9) were investigated under 35 and 500 fs pulses. • At high fluence regime, the ablation rate at 35 fs in air increased to a plateau, and 500 fs in air and vacuum decreased. • The mechanisms of multiple-photon ionization and impact ionization were included. • The ablation morphologies of smooth zone and laser-induced periodic surface structures were presented and illustrated. • The ablation mechanisms of non-thermal and thermal ablation were included. - Abstract: Ablation rates of K9 glass were studied as a function of femtosecond laser fluences. The central wavelength was 800 nm, and pulse durations of 35 fs and 500 fs in air and vacuum were employed. Ablation thresholds of 0.42 J/cm{sup 2} and 2.1 J/cm{sup 2} were obtained at 35 fs and 500 fs, respectively, which were independent with the ambient conditions and depend on the incident pulse numbers due to incubation effects. The ablation rate of 35 fs pulse laser increased with the increasing of laser fluence in vacuum, while in air condition, it slowly increased to a plateau at high fluence. The ablation rate of 500 fs pulse laser showed an increase at low fluence and a slow drop of ablation rate was observed at high fluence in air and vacuum, which may due to the strong defocusing effects associated with the non-equilibrium ionization of air, and/or the shielding effects of conduction band electrons (CBEs) produced by multi-photon ionization and impact ionization in K9 glass surface. The typical ablation morphologies, e.g. smooth zone and laser-induced periodic surface structures (LIPSS) were also presented and illustrated.

  13. KINETIC MODELS STUDY OF HYDRODESULPHURIZATION VACUUM DISTILLATE REACTION

    Directory of Open Access Journals (Sweden)

    AbdulMunem A. Karim

    2013-05-01

    Full Text Available    This study deals with  kinetics of hydrodesulphurization (HDS reaction of vacuum gas oil (611-833 K which was distillated from Kirkuk crude oil and which was obtained by blending the fractions, light vacuum gas oil (611 - 650 K, medium vacuum gas oil (650-690 K, heavy vacuum gas oil (690-727 K and very heavy vacuum gas oil (727-833 K.   The vacuum gas oil was hydrotreated on a commercial cobalt-molybdenum alumina catalyst presulfied at specified conditions in a laboratory trickle bed reactor. The reaction temperature range (583-643 K,liquid hourly space velocity range (1.5-3.75 h-1 and hydrogen pressure was kept constant at 3.5 MPa with hydrogen to oil ratio about 250 lt/lt.           The conversion results for desulphurization reaction appeared to obey the second order reaction. According to this model, the rate constants for desulphurization reaction were determined. Finally, the apparent activation energy (Ea, enthalpy of activation ( H* and entropy ( S* were calculated based on the values of rate constant (k2 and were equal 80.3792 KJ/mole, 75.2974 KJ/mole and 197.493 J/mole, respectively.

  14. Cryogenic Vacuum Insulation for Vessels and Piping

    Science.gov (United States)

    Kogan, A.; Fesmire, J.; Johnson, W.; Minnick, J.

    2010-01-01

    Cryogenic vacuum insulation systems, with proper materials selection and execution, can offer the highest levels of thermal performance. Three areas of consideration are vital to achieve the optimum result: materials, representative test conditions, and engineering approach for the particular application. Deficiency in one of these three areas can prevent optimum performance and lead to severe inefficiency. Materials of interest include micro-fiberglass, multilayer insulation, and composite arrangements. Cylindrical liquid nitrogen boil-off calorimetry methods were used. The need for standard thermal conductivity data is addressed through baseline testing. Engineering analysis and design factors such as layer thickness, density, and practicality are also considered.

  15. Resonance Fluorescence from an Artificial Atom in Squeezed Vacuum

    Directory of Open Access Journals (Sweden)

    D. M. Toyli

    2016-07-01

    Full Text Available We present an experimental realization of resonance fluorescence in squeezed vacuum. We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier. We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields. Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys. Rev. Lett. 58, 2539 (1987], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments.

  16. 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...

  17. Low emittance coatings and the thermal performance of vacuum glazing

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yueping; Hyde, Trevor J.; Zhao, Junfu; Wang, Jinlei; Huang, Ye [Centre for Sustainable Technologies, School of the Built Environment, University of Ulster, Newtownabbey, BT37 0QB, N. Ireland (United Kingdom); Eames, Philip C. [School of Engineering, University of Warwick, Coventry, CV4 7AL (United Kingdom); Norton, Brian [Dublin Institute of Technology, Aungier Street, Dublin 2 (Ireland)

    2007-01-15

    The thermal performances of vacuum glazings employing coatings with emittance between 0.02 and 0.16 were simulated using a three-dimensional finite volume model. Physical samples of vacuum glazings with hard and soft coatings with emittance of 0.04, 0.12 and 0.16 were fabricated and their thermal performance characterised experimentally using a guarded hot box calorimeter. Good agreement was found between experimental and theoretical thermal performances for both a vacuum glazing with a soft coating (emittance 0.04) and those with hard coatings (emittance 0.12 and 0.16). Simulations showed that for a low value of emittance (e.g. 0.02), the use of two low-emittance coatings gives limited improvement in thermal performance of the glazing system. The use of a single high performance low-emittance coating in a vacuum glazing has been shown to provide excellent performance. (author)

  18. Two year operational experience with the TPS vacuum system

    Science.gov (United States)

    Yang, Y. C.; Chan, C. K.; Sheng, I. C.; Huang, I. T.; Y Chung, J.; Liang, C. C.

    2017-07-01

    The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper.

  19. Observation of the Phononic Lamb Shift with a Synthetic Vacuum

    Directory of Open Access Journals (Sweden)

    T. Rentrop

    2016-11-01

    Full Text Available In contrast to classical empty space, the quantum vacuum fundamentally alters the properties of embedded particles. This paradigm shift allows one to explain the discovery of the celebrated Lamb shift in the spectrum of the hydrogen atom. Here, we engineer a synthetic vacuum, building on the unique properties of ultracold atomic gas mixtures, offering the ability to switch between empty space and quantum vacuum. Using high-precision spectroscopy, we observe the phononic Lamb shift, an intriguing many-body effect originally conjectured in the context of solid-state physics. We find good agreement with theoretical predictions based on the Fröhlich model. Our observations establish this experimental platform as a new tool for precision benchmarking of open theoretical challenges, especially in the regime of strong coupling between the particles and the quantum vacuum.

  20. The AD vacuum system construction and commissioning

    CERN Document Server

    Brouet, M; Klette, H; Strubin, Pierre M

    1999-01-01

    CERN has built a new experimental facility, called the Antiproton Decelerator (AD), by transforming two existing machines: the "Antiproton Collector" (AC) and the "Antiproton Accumulator" (AA). To achieve adequate beam performance once the antiproton beam is decelerated to its final value of 0.1 GeV/c, it was necessary to lower the average pressure by nearly two orders of magnitude. For this purpose, a large number of additional pumps were installed and a very careful preparation was applied to a variety of special machine equipment which, in its original construction, was not designed for ultra-high vacuum operation. An important improvement in the outgassing rates was achieved through an extended, mild bake-out of tanks and vacuum vessels containing large amounts of ferrite material and multi-layer thermal insulation. This paper describes the necessary modifications of the vacuum system and in more detail the various steps taken to obtain the required pressure in the low 10/sup -10/ mbar range. It will also...

  1. The AD Vacuum System Construction and Commissioning

    CERN Document Server

    Brouet, M; Klette, H; Strubin, Pierre M

    1999-01-01

    CERN has built a new experimental facility, called the Antiproton Decelerator (AD), by transforming two existing machines: the "Antiproton Collector" (AC) and the "Antiproton Accumulator" (AA). To achieve adequate beam performance once the antiproton beam is decelerated to its final value of 0.1 GeV/c, it was necessary to lower the average pressure by nearly two orders of magnitude. For this purpose, a large number of additional pumps were installed and a very careful preparation was applied to a variety of special machine equipment which, in its original construction, was not designed for ultra-high vacuum operation. An important improvement in the outgassing rates was achieved through an extended, mild bake-out of tanks and vacuum vessels containing large amounts of ferrite material and multi-layer thermal insulation. This paper describes the necessary modifications of the vacuum system and in more detail the various steps taken to obtain the required pressure in the low 10-10 mbar range. It will also repor...

  2. Vacuum evacuated thermal storage in Sengenthal

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, B.; Hofbeck, K. [Georg-Simon-Ohm Hochschule Nuernberg (Germany). Fakultaet Allgemeinwissenschaften; Faulstich, M. [Technische Univ. Muenchen (Germany). Lehrstuhl fuer Rohstoff- und Energietechnologie

    2010-07-01

    This paper describes a vacuum insulated and stratified thermal hot water storage which will be built in Sengenthal in March 2011. The thermal storage is loaded with different types of renewable energy sources, especially firewood and solar thermal energy. With the high efficient tank it is possible to reduce the carbon dioxide emission by 90% and reduce the thermal losses of the storage by 80%. Within the project in Sengenthal the vacuum evacuated storage saves expectedly about 7.500 Euro fuel costs each year without regarding the advance in prices. This fact is caused by the substitution of a gas boiler by using the described tank as a buffer tank within a local heating plant which is covered by a firewood boiler. The concrete problem of the local heating plant was the fact that the power of the firewood boiler is too low to cover the demand of a new building. Without the described thermal storage with vacuum insulation there would be a need of an additional gas boiler. (orig.)

  3. Vacuum window glazings for energy-efficient buildings

    Energy Technology Data Exchange (ETDEWEB)

    Benson, D.K.; Smith, L.K.; Tracy, C.E.; Potter, T.; Christensen, C. (Solar Energy Research Inst., Golden, CO (USA)); Soule, D.E. (Western Illinois Univ., Macomb, IL (USA))

    1990-05-01

    The technical feasibility of a patented, laser-welded, evacuated insulating window was studied. The window has two edge-sealed sheets of glass separated by 0.5-mm glass spheres spaced 30 mm apart in a regular array. A highly insulating frame is required and several designs were analyzed. The vacuum window's combination of high solar transmittance and low thermal conductance makes it superior to many other windows in cold climates. In the US Pacific Northwest, the vacuum window could save about 6 MJ of heating energy annually per square meter of window in comparison to conventional, double-glazed windows. A large, vacuum laser-welding facility was designed and installed to conduct glass welding experiments and to fabricate full-sized vacuum windows. Experiments confirmed the feasibility of laser-sealing glass in vacuum but identified two difficulties. Under some circumstances, bubbles of dissolved gases form during welding and weaken the seal. Glass also vaporizes and contaminates the laser beam steering mirror. A novel moving metal foil mirror was developed to circumvent the contamination problem, but it has not yet been used to complete welding experiments and fabricate full-sized vacuum windows. 63 refs., 53 figs., 19 tabs.

  4. Suppression of shunting current in a magnetically insulated coaxial vacuum diode

    Science.gov (United States)

    Yalandin, M. I.; Mesyats, G. A.; Rostov, V. V.; Sharypov, K. A.; Shpak, V. G.; Shunailov, S. A.; Ulmaskulov, M. R.

    2015-06-01

    Real-time investigations of the dynamics of explosive electron emission from a high-voltage cathode holder made of nonmagnetic stainless steel in a magnetically insulated coaxial vacuum diode have been performed. It has been shown that aging the cathode with several tens of voltage pulses at a field of 1-2 MV/cm provides a stray emission delay ranging from hundreds of picoseconds to a nanosecond or more. In addition, the magnetic field must be configured so that the magnetic lines would not cross the vacuum gap between the diode case and the cathode holder in the region behind the emitting edge of the cathode. These efforts provide conditions for stable emission of the working beam from a graphite cathode with a sharp emitting edge.

  5. The Epidemiology of Overuse Conditions in Youth Football and High School Football Players.

    Science.gov (United States)

    Morris, Kevin; Simon, Janet E; Grooms, Dustin R; Starkey, Chad; Dompier, Thomas P; Kerr, Zachary Y

    2017-10-01

    High-intensity sport training at the youth level has led to increased concern for overuse conditions. Few researchers have examined overuse conditions in youth sports.   To examine the rates, risks, and distributions of overuse conditions between youth and high school football players.   Descriptive epidemiologic study.   Youth and high school football teams.   The Youth Football Safety Study (YFSS) investigated youth football athletes from age 5 to 14 years. The National Athletic Treatment, Injury and Outcomes Network (NATION) focused on high school football athletes 14 to 18 years old. The YFSS data consisted of 210 team-seasons, and the NATION data consisted of 138 team-seasons.   Athletic trainers collected football injury and exposure data during the 2012 and 2013 seasons. Injury rates, risks, and distributions were calculated, with injury rate ratios, risk ratios, and injury proportion ratios with 95% confidence intervals (CIs) comparing youth and high school football players.   The YFSS reported 1488 injuries, of which 53 (3.6%) were overuse conditions. The NATION reported 12 013 injuries, of which 339 (2.8%) were overuse conditions. The overuse condition rate did not differ between high school and youth football (3.93 versus 3.72/10 000 athlete-exposures; injury rate ratio = 1.06; 95% CI = 0.79, 1.41). However, the 1-season risk of overuse condition was higher in high school than in youth football players (2.66% versus 1.05%; risk ratio = 2.53; 95% CI = 1.84, 3.47). Compared with high school football players, youth football players had greater proportions of overuse conditions that were nontime loss (ie, high school football players. However, differences existed between the 2 levels of competition. Although additional research on the incidence of overuse conditions across all youth and high school sports is needed, these findings may highlight the need for programming that is specific to competition level.

  6. Microscale Digital Vacuum Electronic Gates

    Science.gov (United States)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  7. 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.

  8. Enhanced Photocatalytic Activity of Vacuum activated TiO2 Induced by Oxygen Vacancies.

    Science.gov (United States)

    Dong, Guoyan; Wang, Xin; Chen, Zhiwu; Lu, Zhenya

    2017-12-18

    TiO2 (Degussa P25) photocatalysts harboring an abundant oxygen vacancies (vacuum P25) were manufactured using a simple and economic vacuum deoxidation process. Control experiments showed that temperature and time of vacuum deoxidation had a significant effect on vacuum P25 photocatalytic activity. After 240 min of visible light illumination, the optimal vacuum P25 photocatalysts (vacuum deoxidation treated at 330°C for 3h) reaches as high as 94% and 88% of photodegradation efficiency for Rhodamine B (RhB) and tetracycline respectively, which are around 4.5 and 4.9 times as that of pristine P25. The XPS, PL and EPR analyses indicated that the oxygen vacancies were produced in the vacuum P25 during the vacuum deoxidation process. The oxygen vacancies states can produce vacancy energy level located below the conduction band minimum, which resulting in the band gap narrowing, thus extending the photoresponse wavelength range of vacuum P25. The positron annihilation analysis indicated that the concentrations ratio of bulk and surface oxygen vacancies could be adjusted by changing the vacuum deoxidation temperature and time. Decreasing the ratio of bulk and surface oxygen vacancies was shown to improve photo-generated electron-hole pairs separation efficiency, which leads to an obvious enhancement of the visible photocatalytic activities of vacuum P25. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  9. Melt-Conditioned, High-Pressure Die Casting of Mg-Zn-Y Alloy

    Science.gov (United States)

    Xia, Mingxu; Mitra, Subhajit; Dhindaw, Brij; Liu, Guojun; Fan, Zhongyun

    2010-02-01

    The liquid Mg-Zn-Y alloy was conditioned by an application of high-intensive shearing with a pair of intermesh twin screws prior to high-pressure die casting (HPDC). Melt conditioning produces a uniform microstructure with fine grain size and high integrity. The microstructure was analyzed thoroughly, and the solidification characteristics of the melt-conditioned HPDC (MC-HPDC) structure were discussed. The enhancement in I-phase precipitation and the improvement in mechanical properties of MC-HPDC Mg-Zn-Y alloy can be achieved through cyclic annealing.

  10. BEHAVIOUR OF BACKFILL MATERIALS FOR ELECTRICAL GROUNDING SYSTEMS UNDER HIGH VOLTAGE CONDITIONS

    Directory of Open Access Journals (Sweden)

    S. C. LIM

    2015-06-01

    Full Text Available Backfill materials like Bentonite and cement are effective in lowering grounding resistance of electrodes for a considerable period. During lightning, switching impulses and earth fault occurrences in medium and high voltage networks, the grounding system needs to handle extremely high currents either for a short duration or prolonged period respectively. This paper investigates the behaviour of bentonite, cement and sand under impulse and alternating high voltage (50Hz conditions. Fulguritic-formation was observed in all materials under alternating high voltage. The findings reveal that performance of grounding systems under high voltage conditions may significantly change from the outcomes anticipated at design stage.

  11. Laboratory Experiments on Propagating Plasma Bubbles into Vacuum, Vacuum Magnetic Field, and Background Plasmas

    Science.gov (United States)

    Lynn, Alan G.; Zhang, Yue; Gilmore, Mark; Hsu, Scott

    2014-10-01

    We discuss the dynamics of plasma ``bubbles'' as they propagate through a variety of background media. These bubbles are formed by a pulsed coaxial gun with an externally applied magnetic field. Bubble parameters are typically ne ~1020 m-3, Te ~ 5 - 10 eV, and Ti ~ 10 - 15 eV. The structure of the bubbles can range from unmagnetized jet-like structures to spheromak-like structures with complex magnetic flux surfaces. Some of the background media the bubbles interact with are vacuum, vacuum with magnetic field, and other magnetized plasmas. These bubbles exhibit different qualitative behavior depending on coaxial gun parameters such as gas species, gun current, and gun bias magnetic field. Their behavior also depends on the parameters of the background they propagate through. Multi-frame fast camera imaging and magnetic probe data are used to characterize the bubble evolution under various conditions.

  12. In situ X-ray photoelectron spectroscopy study of complex oxides under gas and vacuum environments

    Science.gov (United States)

    Paloukis, F.; Papazisi, K. M.; Balomenou, S. P.; Tsiplakides, D.; Bournel, F.; Gallet, J.-J.; Zafeiratos, S.

    2017-11-01

    For several decades an open question in many X-ray photoelectron spectroscopy (XPS) studies was whether or not the results obtained in ultra-high vacuum conditions (UHV) were representative of the sample state in gas atmospheres. As a consequence, near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) was received by surface scientists as an important tool for in situ characterization of the gas-solid interactions. However, it is not yet clear how, if at all, the surface state formed in contact with the gas is modified when this gas is evacuated. In this work we compare synchrotron-based XPS results recorded at 300 °C on Ni/yttria- stabilized zirconia cermet and La0.75Sr0.25Cr0.9Fe0.1O3 perovskite, under 3.5 mbar O2 and UHV environments. We found that the surface state formed in O2 is maintained to a large extent under vacuum. In addition, we demonstrate that the correlation of XPS spectra recorded in the two conditions can provide information regarding the electrical conductivity of the specific surface sites of these complex oxides. Our findings suggest that comparison of XPS measurements in gas and in vacuum environments might be particularly useful in applications where the electronic conductivity at the surface plays a crucial role, as for example in solid oxide electrochemical devices.

  13. Vacuum chamber 'bicone'

    CERN Multimedia

    1977-01-01

    This chamber is now in the National Museum of History and Technology, Smithsonian Institution, Washington, DC, USA, where it was exposed in an exhibit on the History of High Energy Accelerators (1977).

  14. Endo-vacuum assisted closure treatment for rectal anastomotic insufficiency.

    Science.gov (United States)

    Mees, Soeren Torge; Palmes, Daniel; Mennigen, Rudolf; Senninger, Norbert; Haier, Joerg; Bruewer, Matthias

    2008-04-01

    Anastomotic insufficiency in patients with colorectal anastomosis is a major complication with high morbidity and mortality. Local treatment with transrectal lavage and drainage can be considered in patient without peritonitis. In order to prevent prolonged wound closure and secondary complications during conservative treatment we investigated the vacuum assisted closure (VAC) in this setting. Ten patients with anastomotic insufficiency after colorectal resections, who did not require transabdominal interventions, were treated with an Endo-vacuum assisted closure dressing (Group A; n = 5) or by transrectal lavage (Group B; n = 5). Time for wound healing, duration of hospitalization and pain assessment were compared in both groups. The Endo-vacuum assisted closure treatment was performed for a median time of 27 days without any vacuum assisted closure associated complications. Wound healing was significantly accelerated in Group A compared to Group B. Time in hospital was slightly shortened in patients with Endo-vacuum assisted closure. Pain assessment in both groups did not show any significant differences. Endo-vacuum assisted closure therapy is a novel approach that can be considered in diverted patients with failed colorectal anastomoses. Larger randomized trials that include complete cost-benefit analyses are needed to establish its role in this setting.

  15. 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.

  16. Sand in the salt marsh : Contribution of high-energy conditions to salt-marsh accretion

    NARCIS (Netherlands)

    de Groot, Alma V.; Veeneklaas, Roos M.; Bakker, Jan P.

    2011-01-01

    The environmental dynamics at barrier-island salt marshes are reflected in lateral and vertical textural patterns of the marsh sediment. During normal conditions, fine-grained sediment is deposited, whereas during high-energy conditions also sand accretion can occur. This paper describes the

  17. Sand in the salt marsh: Contribution of high-energy conditions to salt-marsh accretion

    NARCIS (Netherlands)

    Groot, de A.V.; Veeneklaas, R.M.; Bakker, J.P.

    2011-01-01

    The environmental dynamics at barrier-island salt marshes are reflected in lateral and vertical textural patterns of the marsh sediment. During normal conditions, fine-grained sediment is deposited, whereas during high-energy conditions also sand accretion can occur. This paper describes the

  18. Very-Low-Cost, Rugged Vacuum System

    Science.gov (United States)

    Kline-Schoder, Robert; Sorensen, Paul; Passow, Christian; Bilski, Steve

    2013-01-01

    NASA, DoD, DHS, and commercial industry have a need for miniaturized, rugged, low-cost vacuum systems. Recent advances in sensor technology have led to the development of very small mass spectrometer detectors as well as other miniature analytical instruments. However, the vacuum systems to support these sensors remain large, heavy, and power-hungry. To meet this need, a miniaturized vacuum system was created based on a very small, rugged, and inexpensive- to-manufacture molecular drag pump (MDP). The MDP is enabled by the development of a miniature, veryhigh- speed, rugged, low-power, brushless DC motor optimized for wide temperature operation and long life. Such a pump represents an order-of-magnitude reduction in mass, volume, and cost over current, commercially available, state-ofthe- art vacuum pumps. The vacuum system consists of the MDP coupled to a ruggedized rough pump (for terrestrial applications or for planets with substantial atmospheres). The rotor in the MDP consists of a simple smooth cylinder of aluminum spinning at approximately 200,000 RPM inside an outer stator housing. The pump stator comprises a cylindrical aluminum housing with one or more specially designed grooves that serve as flow channels. To minimize the length of the pump, the gas is forced down the flow channels of the outer stator to the base of the pump. The gas is then turned and pulled toward the top through a second set of channels cut into an inner stator housing that surrounds the motor. The compressed gas then flows down channels in the motor housing to the exhaust port of the pump. The exhaust port of the pump is connected to a diaphragm or scroll pump. This pump delivers very high performance in a very small envelope. The design was simplified so that a smaller compression ratio, easier manufacturing process, and enhanced ruggedness can be achieved at the lowest possible cost. The machining of the rotor and stators is very simple compared to that necessary to fabricate TMP

  19. Cleaner Vacuum-Bag Curing

    Science.gov (United States)

    Clemons, J. M.; Penn, B. G.; Ledbetter, Frank E., III; Daniels, J. G.

    1987-01-01

    Improvement upon recommended procedures saves time and expense. Autoclave molding in vacuum bag cleaner if adhesive-backed covering placed around caul plate as well as on mold plate. Covering easy to remove after curing and leaves caul plate free of resin deposits.

  20. Brine Distribution after Vacuum Saturation

    DEFF Research Database (Denmark)

    Hedegaard, Kathrine; Andersen, Bertel Lohmann

    1999-01-01

    Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs...