Germanium detector vacuum encapsulation

NASA Technical Reports Server (NTRS)

Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

1991-01-01

This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

Progress in vacuum susceptibilities and their applications to the chiral phase transition of QCD

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

Cui, Zhu-Fang, E-mail: phycui@nju.edu.cn; State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, CAS, Beijing, 100190; Hou, Feng-Yao

2015-07-15

The QCD vacuum condensates and various vacuum susceptibilities are all important parameters which characterize the nonperturbative properties of the QCD vacuum. In the QCD sum rules external field formula, various QCD vacuum susceptibilities play important roles in determining the properties of hadrons. In this paper, we review the recent progress in studies of vacuum susceptibilities together with their applications to the chiral phase transition of QCD. The results of the tensor, the vector, the axial–vector, the scalar, and the pseudo-scalar vacuum susceptibilities are shown in detail in the framework of Dyson–Schwinger equations.

Milking performance evaluation and factors affecting milking claw vacuum levels with flow simulator.

PubMed

Enokidani, Masafumi; Kawai, Kazuhiro; Shinozuka, Yasunori; Watanabe, Aiko

2017-08-01

Milking performance of milking machines that matches the production capability of dairy cows is important in reducing the risk of mastitis, particularly in high-producing cows. This study used a simulated milking device to examine the milking performance of the milking system of 73 dairy farms and to analyze the factors affecting claw vacuum. Mean claw vacuum and range of fluctuation of claw vacuum (claw vacuum range) were measured at three different flow rates: 5.7, 7.6 and 8.7 kg/min. At the highest flow rate, only 16 farms (21.9%) met both standards of mean claw vacuum ≥35 kPa and claw vacuum range ≤ 7 kPa, showing that milking systems currently have poor milking performance. The factors affecting mean claw vacuum were claw type, milk-meter and vacuum shut-off device; the factor affecting claw vacuum range was claw type. Examination of the milking performance of the milking system using a simulated milking device allows an examination of the performance that can cope with high producing cows, indicating the possibility of reducing the risk of mastitis caused by inappropriate claw vacuum. © 2016 Japanese Society of Animal Science.

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

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

Kohri, Kazunori; Matsui, Hiroki, E-mail: kohri@post.kek.jp, E-mail: matshiro@post.kek.jp

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

Proceedings of the twenty sixth international symposium on discharges and electrical insulation in vacuum. V. 2

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

NONE

2014-07-01

Vacuum science and technology has made vital contributions in high technology areas like space, high energy particle accelerators, plasma devices, pulse power, electronics, vacuum interrupters, thin films, melting and refining of metals/alloys, extraction and processing of advanced materials. Vacuum discharges, vacuum arc physics and technology and various applications towards vacuum interrupters, pulse power and particle accelerator are the main themes for this symposium. Papers relevant to INIS are indexed separately.

Proceedings of the twenty sixth international symposium on discharges and electrical insulation in vacuum. V. 1

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

NONE

2014-07-01

Vacuum science and technology has made vital contributions in high technology areas like space, high energy particle accelerators, plasma devices, pulse power, electronics, vacuum interrupters, thin films, melting and refining of metals/alloys, extraction and processing of advanced materials. Vacuum discharges, vacuum arc physics and technology and various applications towards vacuum interrupters, pulse power and particle accelerator are the main themes for this symposium. Papers relevant to INIS are indexed separately.

Evacuated optical structure comprising optical bench mounted to sidewall of vacuum chamber in a manner which inhibits deflection and rotation of the optical bench

DOEpatents

Bowers, Joel M.

1994-01-01

An improved evacuated optical structure is disclosed comprising an optical bench mounted in a vacuum vessel in a manner which inhibits transmission of movement of the vacuum vessel to the optical bench, yet provides a compact and economical structure. The vacuum vessel is mounted, through a sidewall thereof, to a support wall at four symmetrically positioned and spaced apart areas, each of which comprises a symmetrically positioned group of mounting structures passing through the sidewall of the vacuum vessel. The optical bench is pivotally secured to the vacuum vessel by four symmetrically spaced apart bolts and spherical bearings, each of which is centrally positioned within one of the four symmetrically positioned groups of vacuum vessel mounting structures. Cover plates and o-ring seals are further provided to seal the vacuum vessel mounting structures from the interior of the vacuum vessel, and venting bores are provided to vent trapped gases in the bores used to secure the cover plates and o-rings to the vacuum vessel. Provision for detecting leaks in the mounting structures from the rear surface of the vacuum vessel sidewall facing the support wall are also provided. Deflection to the optical bench within the vacuum vessel is further minimized by tuning the structure for a resonant frequency of at least 100 Hertz.

Enhanced Photocatalytic Activity of Vacuum-activated TiO2 Induced by Oxygen Vacancies.

PubMed

Dong, Guoyan; Wang, Xin; Chen, Zhiwu; Lu, Zhenya

2018-05-01

TiO 2 (Degussa P25) photocatalysts harboring 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 3 h) reach 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 vacancy states can produce vacancy energy level located below the conduction band minimum, which resulting in the bandgap 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 photogenerated electron-hole pair separation efficiency, which leads to an obvious enhancement of the visible photocatalytic activities of Vacuum P25. © 2017 The American Society of Photobiology.

Evacuated optical structure comprising optical bench mounted to sidewall of vacuum chamber in a manner which inhibits deflection and rotation of the optical bench

DOEpatents

Bowers, J.M.

1994-04-19

An improved evacuated optical structure is disclosed comprising an optical bench mounted in a vacuum vessel in a manner which inhibits transmission of movement of the vacuum vessel to the optical bench, yet provides a compact and economical structure. The vacuum vessel is mounted, through a sidewall thereof, to a support wall at four symmetrically positioned and spaced apart areas, each of which comprises a symmetrically positioned group of mounting structures passing through the sidewall of the vacuum vessel. The optical bench is pivotally secured to the vacuum vessel by four symmetrically spaced apart bolts and spherical bearings, each of which is centrally positioned within one of the four symmetrically positioned groups of vacuum vessel mounting structures. Cover plates and o-ring seals are further provided to seal the vacuum vessel mounting structures from the interior of the vacuum vessel, and venting bores are provided to vent trapped gases in the bores used to secure the cover plates and o-rings to the vacuum vessel. Provision for detecting leaks in the mounting structures from the rear surface of the vacuum vessel sidewall facing the support wall are also provided. Deflection to the optical bench within the vacuum vessel is further minimized by tuning the structure for a resonant frequency of at least 100 Hertz. 10 figures.

Comparison of work rates, energy expenditure, and perceived exertion during a 1-h vacuuming task with a backpack vacuum cleaner and an upright vacuum cleaner.

PubMed

Mengelkoch, Larry J; Clark, Kirby

2006-03-01

The purpose of this study was to evaluate two types of industrial vacuum cleaners, in terms of cleaning rates, energy expenditure, and perceived exertion. Twelve industrial cleaners (six males and six females, age 28-39 yr) performed two 1-h vacuuming tasks with an upright vacuum cleaner (UVC) and a backpack vacuum cleaner (BPVC). Measures for oxygen uptake (VO2) and ratings of perceived exertion (RPE) were collected continuously during the 1-h vacuuming tasks. Cleaning rates for the UVC and BPVC were 7.23 and 14.98 m2min(-1), respectively. On a separate day subjects performed a maximal treadmill exercise test to determine their maximal aerobic capacity (peak VO2). Average absolute energy costs (in Metabolic equivalents), relative energy costs of the vacuum task compared to the subjects' maximal aerobic capacity (% peak VO2), and RPE responses for the 1-h vacuuming tasks were similar between vacuum cleaners, but % peak VO2 and RPE values differed between genders. These results indicate that the BPVC was more efficient than the UVC. With the BPVC, experienced workers vacuumed at a cleaning rate 2.07 times greater than the UVC and had similar levels of energy expenditure and perceived effort, compared to the slower cleaning rate with the UVC.

Assembly of a Vacuum Chamber: A Hands-On Approach to Introduce Mass Spectrometry

ERIC Educational Resources Information Center

Bussie`re, Guillaume; Stoodley, Robin; Yajima, Kano; Bagai, Abhimanyu; Popowich, Aleksandra K.; Matthews, Nicholas E.

2014-01-01

Although vacuum technology is essential to many aspects of modern physical and analytical chemistry, vacuum experiments are rarely the focus of undergraduate laboratories. We describe an experiment that introduces students to vacuum science and mass spectrometry. The students first assemble a vacuum system, including a mass spectrometer. While…

21 CFR 864.9125 - Vacuum-assisted blood collection system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

21 CFR 864.9125 - Vacuum-assisted blood collection system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

21 CFR 864.9125 - Vacuum-assisted blood collection system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

21 CFR 864.9125 - Vacuum-assisted blood collection system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

21 CFR 864.9125 - Vacuum-assisted blood collection system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

Demonstrations with a Vacuum: Old Demonstrations for New Vacuum Pumps.

ERIC Educational Resources Information Center

Greenslade, Thomas B., Jr.

1989-01-01

Explains mechanisms of 19th-century vacuum pumps. Describes demonstrations using the pump including guinea and feather tube, aurora tube, electric egg, Gassiots cascade, air mill, bell in vacuum, density and buoyancy of air, fountain in vacuum, mercury shower, palm and bladder glasses, Bacchus demonstration, pneumatic man-lifter, and Magdeburg…

Effective Porosity Measurements by Wet- and Dry-type Vacuum Saturations using Process-Programmable Vacuum Saturation System

NASA Astrophysics Data System (ADS)

Lee, T. J.; Lee, K. S., , Dr; Lee, S. K.

2017-12-01

One of the most important factors in measuring effective porosity by vacuum saturation method is that the air in the pore space can be fully substituted by water during the vacuum saturation process. International Society of Rock Mechanics (ISRM) suggests vacuuming a rock sample submerged in the water, while American Society of Test and Materials (ASTM) vacuuming the sample and water separately and then pour the water to the sample. In this study, we call the former wet-type vacuum saturation (WVS) method and the latter dry-type vacuum saturation (DVS) method, and compare the effective porosity measured by the two different vacuum saturation processes. For that purpose, a vacuum saturation system has been developed, which can support both WVS and DVS by only changing the process by programming. Comparison of effective porosity has been made for a cement mortar and rock samples. As a result, DVS can substitute more void volume to water than WVS, which in turn insists that DVS can provide more exact value of effective porosity than WVS.

Lightweight Vacuum Jacket for Cryogenic Insulation. Volume 1

NASA Technical Reports Server (NTRS)

Barclay, D. L.; Bell, J. E.; Brogren, E. W.; Straayer, J. W.

1975-01-01

The feasibility of producing a lightweight vacuum jacket using state-of-the-art technology and materials was examined. Design and analytical studies were made on a full-scale, orbital maneuvering system fuel tank. Preliminary design details were made for the tank assembly, including an optimized vacuum jacket and multilayer insulation system. A half-scale LH2 test model was designed and fabricated, and a force/stiffness proof test was conducted on the vacuum jacket. A vacuum leak rate of .000001 atmosphere ml of helium per second was measured, approximately 1500 hours of vacuum pressure were sustained, and 29 vacuum-pressure cycles were experienced prior to failure.

Lightweight Vacuum Jacket for Cryogenic Insulation - Appendices to Final Report. Volume 2

NASA Technical Reports Server (NTRS)

Barclay, D. L.; Bell, J. E.; Brogren, E. W.; Straayer, J. W.

1975-01-01

The feasibility is demonstrated of producing a lightweight vacuum jacket using state-of-the-art technology and materials. Design and analytical studies were made on an orbital maneuvering system fuel tank. Preliminary design details were completed for the tank assembly which included an optimized vacuum jacket and multilayered insulation system. A half-scale LH2 test model was designed and fabricated and a force/stiffness proof test was conducted on the vacuum jacket. A vacuum leak rate of 0.00001 was measured, approximately 1500 hours of vacuum pressure was sustained, and 29 vacuum pressure cycles were experienced prior to failure. For vol. 1, see N75-26192.

Redesigning the continuous vacuum sealer packaging machine to improve the processing speed

NASA Astrophysics Data System (ADS)

Belo, J. B.; Widyanto, S. A.; Jamari, J.

2017-01-01

Vacuum sealer as a product packaging tool of food products to be able to vacuum air inside the plastic which is filled with food products and it causes the pressure lower. In this condition, the optimal heating temperature is reached in a shorter time, so that damage on plastic sealer of vacuumed food products could be prevented to be more effective and efficient. The purpose of this redesigning is to design a vacuum sealer packaging machine continuously through a conveyor mechanism on the packaging quality, time of processing speed of vacuuming food product in the plastic package. This designing process is conducted through several steps of designing and constructing tools until the products are ready to operate. Data analysis is done through quality test of vacuum and sealer to the plastic thickness of 75 µm, 80 µm, and 100 µm with temperature of 170°C, 180°C, 190°C and vacuum duration of 5 seconds, 8 seconds, and 60 seconds. Results of this designing process indicate that vacuum sealer works practically and more optimally with the time of vacuum processing speed of 0 to 1 minute/s; whereas, the pressure of vacuuming suction is until 1e-5 MPa. The results of tensile strength test are at a maximum of 32,796 (N/mm2) and a minimum of 20,155 (N/mm2) and the analysis of plastic composite with EDX. This result shows that the vacuum pressure and the quality of vacuum sealer are better and more efficient.

Research on Melt Degassing Processes of High Conductivity Hard Drawn Aluminum Wire

NASA Astrophysics Data System (ADS)

Xu, Xuexia; Feng, Yanting; Wang, Qing; Li, Wenbin; Fan, Hui; Wang, Yong; Li, Guowei; Zhang, Daoqian

2018-03-01

Degassing effects of ultrasonic and vacuum processes on high conductivity hard drawn aluminum melt were studied. Results showed that the degassing efficiency improved with the increase of ultrasonic power within certain range, stabilizing at 70% with 240W. For vacuum degassing process, hydrogen content of aluminum melt decreased with the loading time and was linear with logarithm of vacuum degree. Comparison of degassing effects of ultrasonic, vacuum, vacuum-ultrasonic degassing process showed that vacuum-ultrasonic process presented optimal effect.

Investigation of Dielectric Breakdown Characteristics for Double-break Vacuum Interrupter and Dielectric Breakdown Probability Distribution in Vacuum Interrupter

NASA Astrophysics Data System (ADS)

Shioiri, Tetsu; Asari, Naoki; Sato, Junichi; Sasage, Kosuke; Yokokura, Kunio; Homma, Mitsutaka; Suzuki, Katsumi

To investigate the reliability of equipment of vacuum insulation, a study was carried out to clarify breakdown probability distributions in vacuum gap. Further, a double-break vacuum circuit breaker was investigated for breakdown probability distribution. The test results show that the breakdown probability distribution of the vacuum gap can be represented by a Weibull distribution using a location parameter, which shows the voltage that permits a zero breakdown probability. The location parameter obtained from Weibull plot depends on electrode area. The shape parameter obtained from Weibull plot of vacuum gap was 10∼14, and is constant irrespective non-uniform field factor. The breakdown probability distribution after no-load switching can be represented by Weibull distribution using a location parameter. The shape parameter after no-load switching was 6∼8.5, and is constant, irrespective of gap length. This indicates that the scatter of breakdown voltage was increased by no-load switching. If the vacuum circuit breaker uses a double break, breakdown probability at low voltage becomes lower than single-break probability. Although potential distribution is a concern in the double-break vacuum cuicuit breaker, its insulation reliability is better than that of the single-break vacuum interrupter even if the bias of the vacuum interrupter's sharing voltage is taken into account.

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

Vacuum Energy and Inflation: 4. An Inflationary Universe

ERIC Educational Resources Information Center

Huggins, Elisha

2013-01-01

This is the fourth paper in a series of four. The first paper in the series, "Vacuum Energy and Inflation: 1. A Liter of Vacuum Energy" [EJ1024183] discusses an example of vacuum energy. Vacuum energy is explained as an energy with a negative pressure whose energy density remains constant in an expanding space. Paper 2, "Vacuum…

Microbial analysis of meatballs cooled with vacuum and conventional cooling.

PubMed

Ozturk, Hande Mutlu; Ozturk, Harun Kemal; Koçar, Gunnur

2017-08-01

Vacuum cooling is a rapid evaporative cooling technique and can be used for pre-cooling of leafy vegetables, mushroom, bakery, fishery, sauces, cooked food, meat and particulate foods. The aim of this study was to apply the vacuum cooling and the conventional cooling techniques for the cooling of the meatball and to show the vacuum pressure effect on the cooling time, the temperature decrease and microbial growth rate. The results of the vacuum cooling and the conventional cooling (cooling in the refrigerator) were compared with each other for different temperatures. The study shows that the conventional cooling was much slower than the vacuum cooling. Moreover, the microbial growth rate of the vacuum cooling was extremely low compared with the conventional cooling. Thus, the lowest microbial growth occurred at 0.7 kPa and the highest microbial growth was observed at 1.5 kPa for the vacuum cooling. The mass loss ratio for the conventional cooling and vacuum cooling was about 5 and 9% respectively.

21 CFR 884.4340 - Fetal vacuum extractor.

Code of Federal Regulations, 2011 CFR

2011-04-01

... means of a suction cup attached to the scalp and is powered by an external vacuum source. This generic type of device may include the cup, hosing, vacuum source, and vacuum control. (b) Classification...

21 CFR 884.4340 - Fetal vacuum extractor.

Code of Federal Regulations, 2010 CFR

2010-04-01

... means of a suction cup attached to the scalp and is powered by an external vacuum source. This generic type of device may include the cup, hosing, vacuum source, and vacuum control. (b) Classification...

Robot design for a vacuum environment

NASA Technical Reports Server (NTRS)

Belinski, S.; Trento, W.; Imani-Shikhabadi, R.; Hackwood, S.

1987-01-01

The cleanliness requirements for many processing and manufacturing tasks are becoming ever stricter, resulting in a greater interest in the vacuum environment. Researchers discuss the importance of this special environment, and the development of robots which are physically and functionally suited to vacuum processing tasks. Work is in progress at the Center for robotic Systems in Microelectronics (CRSM) to provide a robot for the manufacture of a revolutionary new gyroscope in high vacuum. The need for vacuum in this and other processes is discussed as well as the requirements for a vacuum-compatible robot. Finally, researchers present details on work done at the CRSM to modify an existing clean-room compatible robot for use at high vacuum.

Instrument for measurement of vacuum in sealed thin wall packets

DOEpatents

Kollie, T.G.; Thacker, L.H.; Fine, H.A.

1995-04-18

An instrument is disclosed for the measurement of vacuum within sealed packets, the packets having a wall that it can be deformed by the application of an external dynamic vacuum to an area thereof. The instrument has a detector head for placement against the deformable wall of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall with this deformation or lift monitored by the application of light as via a bifurcated light pipe. Retro-reflected light through the light pipe is monitored with a photo detector. A change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the dynamic vacuum applied through the head be to achieve this initiation of movement is equal to the vacuum within the packet. In a preferred embodiment a vacuum plate is placed beneath the packet to ensure that no deformation occurs on the reverse surface of the packet. A vacuum can be applied to a recess in this vacuum plate, the value of which can be used to calibrate the vacuum transducer in the detector head. 4 figs.

Instrument for measurement of vacuum in sealed thin wall packets

DOEpatents

Kollie, Thomas G.; Thacker, Louis H.; Fine, H. Alan

1995-01-01

An instrument for the measurement of vacuum within sealed packets 12, the packets 12 having a wall 14 that it can be deformed by the application of an external dynamic vacuum to an area thereof. The instrument has a detector head 18 for placement against the deformable wall 14 of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall 14, with this deformation or lift monitored by the application of light as via a bifurcated light pipe 20. Retro-reflected light through the light pipe is monitored with a photo detector 26. A change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the dynamic vacuum applied through the head be to achieve this initiation of movement is equal to the vacuum within the packet 12. In a preferred embodiment a vacuum plate 44 is placed beneath the packet 12 to ensure that no deformation occurs on the reverse surface 16 of the packet. A vacuum can be applied to a recess in this vacuum plate, the value of which can be used to calibrate the vacuum transducer in the detector head.

Investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non-vacuum or vacuum processes.

PubMed

Winter, S; Smith, A; Lappin, D; McDonagh, G; Kirk, B

2017-12-01

Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam sterilizers were tested: a non-vacuum benchtop sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop sterilizer (Lisa; W&H, Bürmoos, Austria). Each sterilizer cycle was completed with three handpieces and each cycle in triplicate. A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0-150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs (N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Vacuum Strength of Two Candidate Glasses for a Space Observatory

NASA Technical Reports Server (NTRS)

Manning, Timothy Andrew; Tucker, Dennis S.; Herren, Kenneth A.; Gregory, Don A.

2007-01-01

The strengths of two candidate glass types for use in a space observatory were measured. Samples of ultra-low expansion glass (ULE) and borosilicate (Pyrex) were tested in air and in vacuum at room temperature (20 degrees C) and in vacuum after being heated to 200 degrees C. Both glasses tested in vacuum showed a significant increase in strength over those tested in air. However, there was no statistical difference between the strength of samples tested in vacuum at room temperature and those tested in vacuum after heating to 200 degrees C.

Vacuum Strength of Two Candidate Glasses for a Space Observatory

NASA Technical Reports Server (NTRS)

Manning, T. a.; Tucker, D. S.; Herren, K. A.; Gregory, D. A.

2007-01-01

The strengths of two candidate glass types for use in a space observatory were measured. Samples of ultra-low expansion glass (ULE) and borosilicate (Pyrex) were tested in air and in vacuum at room temperature (20 C) and in vacuum after being heated to 200 C. Both glasses tested in vacuum showed an increase in strength over those tested in air. However, there was no statistical difference between the strength of samples tested in vacuum at room temperature and those tested in vacuum after heating to 200 C.

Hydrogen detector

DOEpatents

Kanegae, Naomichi; Ikemoto, Ichiro

1980-01-01

A hydrogen detector of the type in which the interior of the detector is partitioned by a metal membrane into a fluid section and a vacuum section. Two units of the metal membrane are provided and vacuum pipes are provided independently in connection to the respective units of the metal membrane. One of the vacuum pipes is connected to a vacuum gauge for static equilibrium operation while the other vacuum pipe is connected to an ion pump or a set of an ion pump and a vacuum gauge both designed for dynamic equilibrium operation.

Running vacuum cosmological models: linear scalar perturbations

NASA Astrophysics Data System (ADS)

Perico, E. L. D.; Tamayo, D. A.

2017-08-01

In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ(H2) or Λ(R). Such models assume an equation of state for the vacuum given by bar PΛ = - bar rhoΛ, relating its background pressure bar PΛ with its mean energy density bar rhoΛ ≡ Λ/8πG. This equation of state suggests that the vacuum dynamics is due to an interaction with the matter content of the universe. Most of the approaches studying the observational impact of these models only consider the interaction between the vacuum and the transient dominant matter component of the universe. We extend such models by assuming that the running vacuum is the sum of independent contributions, namely bar rhoΛ = Σibar rhoΛi. Each Λ i vacuum component is associated and interacting with one of the i matter components in both the background and perturbation levels. We derive the evolution equations for the linear scalar vacuum and matter perturbations in those two scenarios, and identify the running vacuum imprints on the cosmic microwave background anisotropies as well as on the matter power spectrum. In the Λ(H2) scenario the vacuum is coupled with every matter component, whereas the Λ(R) description only leads to a coupling between vacuum and non-relativistic matter, producing different effects on the matter power spectrum.

Improved Vacuum Bazooka

NASA Astrophysics Data System (ADS)

Cockman, John

2003-04-01

This apparatus is a modification to the well-known "vacuum bazooka" (PIRA 2B30.70). My vacuum bazooka is easy to construct and demonstrate, requires no precise fittings, foil, or vacuum grease, and propels ping-pong balls at a tremendous velocity!

Apparatus For Metal/Inert-Gas Welding In Vacuum

NASA Technical Reports Server (NTRS)

Stocks, C. O.

1994-01-01

Metal/inert-gas welding-torch assembly operates in vacuum. Plasma generated in interior chamber and focused onto workpiece in vacuum. Pinch rollers feed wire to weld puddle. Controlled flow of plasma reduces dispersal in vacuum, preventing extinction.

Vacuum status-display and sector-conditioning programs

NASA Astrophysics Data System (ADS)

Skelly, J.; Yen, S.

1990-08-01

Two programs have been developed for observation and control of the AGS vacuum system, which include the following notable features: (1) they incorporate a graphical user interface and (2) they are driven by a relational database which describes the vacuum system. The vacuum system comprises some 440 devices organized into 28 vacuum sectors. The status-display program invites menu selection of a sector, interrogates the relational database for relevant vacuum devices, acquires live readbacks and posts a graphical display of their status. The sector-conditioning program likewise invites sector selection, produces the same status display and also implements process control logic on the sector devices to pump the sector down from atmospheric pressure to high vacuum over a period extending several hours. As additional devices are installed in the vacuum system, the devices are added to the relational database; these programs then automatically include the new devices.

Radiation hard vacuum switch

DOEpatents

Boettcher, Gordon E.

1990-01-01

A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

A radiation hard vacuum switch

DOEpatents

Boettcher, G.E.

1988-07-19

A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

Radiation hard vacuum switch

DOEpatents

Boettcher, Gordon E.

1990-03-06

A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

Outgassing of solid material into vacuum thermal insulation spaces

NASA Technical Reports Server (NTRS)

Wang, Pao-Lien

1994-01-01

Many cryogenic storage tanks use vacuum between inner and outer tank for thermal insulation. These cryogenic tanks also use a radiation shield barrier in the vacuum space to prevent radiation heat transfer. This shield is usually constructed by using multiple wraps of aluminized mylar and glass paper as inserts. For obtaining maximum thermal performance, a good vacuum level must be maintained with the insulation system. It has been found that over a period of time solid insulation materials will vaporize into the vacuum space and the vacuum will degrade. In order to determine the degradation of vacuum, the rate of outgassing of the insulation materials must be determined. Outgassing rate of several insulation materials obtained from literature search were listed in tabular form.

Switching Circuit for Shop Vacuum System

NASA Technical Reports Server (NTRS)

Burley, R. K.

1987-01-01

No internal connections to machine tools required. Switching circuit controls vacuum system draws debris from grinders and sanders in machine shop. Circuit automatically turns on vacuum system whenever at least one sander or grinder operating. Debris safely removed, even when operator neglects to turn on vacuum system manually. Pickup coils sense alternating magnetic fields just outside operating machines. Signal from any coil or combination of coils causes vacuum system to be turned on.

Development of a MEMS-Scale Turbomachinery Based Vacuum Pump

DTIC Science & Technology

2012-06-01

MEMS -SCALE TURBOMACHINERY BASED VACUUM PUMP by Michael J. Shea June 2012 Thesis Advisor: Anthony J. Gannon Second Reader...June 2012 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Development of a MEMS -Scale Turbomachinery Based Vacuum Pump 5...to develop a MEMS scale turbomachinery based vacuum pump. This would allow very high vacuum to be drawn for handheld mass spectroscopy. This

Air bearing vacuum seal assembly

DOEpatents

Booth, Rex

1978-01-01

An air bearing vacuum seal assembly capable of rotating at the speed of several thousand revolutions per minute using an air cushion to prevent the rotating and stationary parts from touching, and a two stage differential pumping arrangement to maintain the pressure gradient between the air cushion and the vacuum so that the leak rate into the vacuum is, for example, less than 1 .times. 10.sup.-4 Pa m.sup.3 /s. The air bearing vacuum seal has particular application for mounting rotating targets to an evacuated accelerator beam tube for bombardment of the targets with high-power charged particle beams in vacuum.

Vacuum extraction failure is associated with a large head circumference.

PubMed

Kabiri, Doron; Lipschuetz, Michal; Cohen, Sarah M; Yagel, Oren; Levitt, Lorinne; Herzberg, Shmuel; Ezra, Yossef; Yagel, Simcha; Amsalem, Hagai

2018-04-24

To determine whether large head circumference increases the risk of vacuum extraction failure. This EMR-based study included all attempted vacuum extractions performed in a tertiary center between January 2010 and June 2015. All term singleton live births were eligible. Cases were divided into four groups: head circumference ≥90th percentile both with birth weight ≥90th percentile and <90th percentile and fetal head circumference <90th percentile with birth weight ≥90th and <90th percentile. Risk of failed vacuum extraction was compared among these groups. Other neonatal and maternal parameters were also evaluated as potential risk factors. Multinomial multivariable regression provided adjusted odds ratio for vacuum extraction failure while controlling for potential confounders. During the study period, 48,007 deliveries met inclusion criteria, of which 3835 had an attempt at vacuum extraction. We identified 215 (5.6%) cases of vacuum extraction failure. The adjusted odds ratios (aOR) for vacuum extraction failure in cases of large fetal head circumference was 2.31 (95%CI, 1.7-3.15, p < .001). Primiparity, prolonged second stage and occipito-posterior presentation were also found to be significant risk factors for failed vacuum extraction. In this study, we found that large head circumference was associated with vacuum extraction failure rather than high birth weight.

Running vacuum cosmological models: linear scalar perturbations

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

Perico, E.L.D.; Tamayo, D.A., E-mail: elduartep@usp.br, E-mail: tamayo@if.usp.br

In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ( H {sup 2}) or Λ( R ). Such models assume an equation of state for the vacuum given by P-bar {sub Λ} = - ρ-bar {sub Λ}, relating its background pressure P-bar {sub Λ} with its mean energy density ρ-bar {sub Λ} ≡ Λ/8π G . This equation of state suggests that the vacuum dynamics is due to an interaction with the matter content of the universe. Most of the approaches studying the observational impact of these models only consider the interactionmore » between the vacuum and the transient dominant matter component of the universe. We extend such models by assuming that the running vacuum is the sum of independent contributions, namely ρ-bar {sub Λ} = Σ {sub i} ρ-bar {sub Λ} {sub i} . Each Λ i vacuum component is associated and interacting with one of the i matter components in both the background and perturbation levels. We derive the evolution equations for the linear scalar vacuum and matter perturbations in those two scenarios, and identify the running vacuum imprints on the cosmic microwave background anisotropies as well as on the matter power spectrum. In the Λ( H {sup 2}) scenario the vacuum is coupled with every matter component, whereas the Λ( R ) description only leads to a coupling between vacuum and non-relativistic matter, producing different effects on the matter power spectrum.« less

[The evolution of vacuum extraction in obstetrics].

PubMed

Nikolov, A

2010-01-01

Vacuum extraction is one of the methods for assisted vaginal delivery. In this article the evolution of vacuum extraction in obstetrics is been discussed. Historical facts and data from the invention up to state-of-the-art vacuum systems in modern obstetrics are presented.

7 CFR 58.423 - Cheese vacuumizing chamber.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Cheese vacuumizing chamber. 58.423 Section 58.423 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....423 Cheese vacuumizing chamber. The vacuum chamber shall be satisfactorily constructed and maintained...

7 CFR 58.423 - Cheese vacuumizing chamber.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Cheese vacuumizing chamber. 58.423 Section 58.423 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....423 Cheese vacuumizing chamber. The vacuum chamber shall be satisfactorily constructed and maintained...

[Laser-induced breakdown spectroscopy system for elements analysis in high-temperature and vacuum environment].

PubMed

Pan, Cong-Yuan; Du, Xue-Wei; An, Ning; Han, Zhen-Yu; Wang, Sheng-Bo; Wei, Wei; Wang, Qiu-Ping

2013-12-01

Laser-induced breakdown spectroscopy (LIBS) is one of the most promising technologies to be applied to metallurgical composition online monitoring in these days. In order to study the spectral characters of LIBS spectrum and to investigate the quantitative analysis method of material composition under vacuum and high temperature environment, a LIBS measurement system was designed and set up which can be used for conducting experiments with high-temperature or molten samples in different vacuum environment. The system consists of a Q-switched Nd : YAG laser used as the light source, lens with different focus lengths used for laser focusing and spectrum signal collecting, a spectrometer used for detecting the signal of LIBS spectrums, and a vacuum system for holding and heating the samples while supplying a vacuum environment. The vacuum was achieved and maintained by a vacuum pump and an electric induction furnace was used for heating the system. The induction coil was integrated to the vacuum system by attaching to a ceramic sealing flange. The system was installed and testified, and the results indicate that the vacuum of the system can reach 1X 10(-4) Pa without heating, while the heating temperature could be about 1 600 degreeC, the system can be used for melting metal samples such as steel and aluminum and get the LIBS spectrum of the samples at the same time. Utilizing this system, LIBS experiments were conducted using standard steel samples under different vacuum or high-temperature conditions. Results of comparison between LIBS spectrums of solid steel samples under different vacuum were achieved, and so are the spectrums of molten and solid steel samples under vacuum environment. Through data processing and theoretical analyzing of these spectrums, the initial results of those experiments are in good agreement with the results that are presently reported, which indicates that the whole system functions well and is available for molten metal LIBS experiment under vacuum environment.

The Classical Vacuum.

ERIC Educational Resources Information Center

Boyer, Timothy H.

1985-01-01

The classical vacuum of physics is not empty, but contains a distinctive pattern of electromagnetic fields. Discovery of the vacuum, thermal spectrum, classical electron theory, zero-point spectrum, and effects of acceleration are discussed. Connection between thermal radiation and the classical vacuum reveals unexpected unity in the laws of…

Troubleshooting crude vacuum tower overhead ejector systems

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

Lines, J.R.; Frens, L.L.

1995-03-01

Routinely surveying tower overhead vacuum systems can improve performance and product quality. These vacuum systems normally provide reliable and consistent operation. However, process conditions, supplied utilities, corrosion, erosion and fouling all have an impact on ejector system performance. Refinery vacuum distillation towers use ejector systems to maintain tower top pressure and remove overhead gases. However, as with virtually all refinery equipment, performance may be affected by a number of variables. These variables may act independently or concurrently. It is important to understand basic operating principles of vacuum systems and how performance is affected by: utilities, corrosion and erosion, fouling, andmore » process conditions. Reputable vacuum-system suppliers have service engineers that will come to a refinery to survey the system and troubleshoot performance or offer suggestions for improvement. A skilled vacuum-system engineer may be needed to diagnose and remedy system problems. The affect of these variables on performance is discussed. A case history is described of a vacuum system on a crude tower in a South American refinery.« less

Characteristics of ring type traveling wave ultrasonic motor in vacuum.

PubMed

Qu, Jianjun; Zhou, Ningning; Tian, Xiu; Jin, Long; Xu, Zhike

2009-03-01

The characteristics of ultrasonic motor strongly depend on the properties of stator/rotor contact interface which are affected by ambient environment. With the developed apparatus, load properties of two ring type traveling wave ultrasonic motors in atmosphere, low vacuum and high vacuum were studied, respectively. Wear of friction material, variations of vacuum degree and the temperature of motor during the experiment were also measured. The results show that load properties of motor A in vacuum were poorer than those in atmosphere, when load torque M(f) was less than 0.55 N m. Compared to motor A, load properties of motor B were affected a little by environmental pressure. Wear of friction material in vacuum was more severe than wear in atmosphere. The temperature of motor in vacuum rose more quickly than it in atmosphere and had not reached equilibrium in 2 h experiment. However, the temperature of motor in atmosphere had reached equilibrium in about forth minutes. Furthermore, outgas was also observed during experiment under vacuum conditions.

Tunneling decay of false vortices

NASA Astrophysics Data System (ADS)

Lee, Bum-Hoon; Lee, Wonwoo; MacKenzie, Richard; Paranjape, M. B.; Yajnik, U. A.; Yeom, Dong-han

2013-10-01

We consider the decay of vortices trapped in the false vacuum of a theory of scalar electrodynamics in 2+1 dimensions. The potential is inspired by models with intermediate symmetry breaking to a metastable vacuum that completely breaks a U(1) symmetry, while in the true vacuum, the symmetry is unbroken. The false vacuum is unstable through the formation of true vacuum bubbles; however, the rate of decay can be extremely long. On the other hand, the false vacuum can contain metastable vortex solutions. These vortices contain the true vacuum inside in addition to a unit of magnetic flux and the appropriate topologically nontrivial false vacuum outside. We numerically establish the existence of vortex solutions which are classically stable; however, they can decay via tunneling. In general terms, they tunnel to a configuration which is a large, thin-walled vortex configuration that is now classically unstable to the expansion of its radius. We compute an estimate for the tunneling amplitude in the semiclassical approximation. We believe our analysis would be relevant to superconducting thin films or superfluids.

Feed-through connector couples RF power into vacuum chamber

NASA Technical Reports Server (NTRS)

Grandy, G. L.

1967-01-01

Feed-through device connects RF power to an RF coil in a vacuum chamber. The coil and leads are water cooled and vacuum tight seals are provided at the junctions. The device incorporates silver soldered copper tubes, polytetrafluoroethylene electrical insulators, and O-ring vacuum seals.

14 CFR 29.1433 - Vacuum systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. (b) Each vacuum air system line and fitting on the discharge side of the pump that might contain...

7 CFR 58.913 - Evaporators and vacuum pans.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

7 CFR 58.913 - Evaporators and vacuum pans.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

7 CFR 58.913 - Evaporators and vacuum pans.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

7 CFR 58.913 - Evaporators and vacuum pans.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

7 CFR 58.913 - Evaporators and vacuum pans.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

Effects of vacuum exposure on stress and spectral shift of high reflective coatings

NASA Astrophysics Data System (ADS)

Stolz, C. J.; Taylor, J. R.; Eickelberg, W. K.; Lindh, J. D.

1992-06-01

The Atomic Vapor Laser Isotope Laser Separation (AVLIS) program operates the world's largest average power dye laser; the dye laser beams are combined, formatted, and transported in vacuum. The optical system is aligned at atmosphere, while the system must meet requirements in vacuum. Therefore, coating performance must be characterized in both atmosphere and vacuum. Changes in stress and spectral shift in ambient and vacuum environments are reported for conventional and dense multilayer dielectric coatings.

Quantum vacuum noise in physics and cosmology.

PubMed

Davies, P. C. W.

2001-09-01

The concept of the vacuum in quantum field theory is a subtle one. Vacuum states have a rich and complex set of properties that produce distinctive, though usually exceedingly small, physical effects. Quantum vacuum noise is familiar in optical and electronic devices, but in this paper I wish to consider extending the discussion to systems in which gravitation, or large accelerations, are important. This leads to the prediction of vacuum friction: The quantum vacuum can act in a manner reminiscent of a viscous fluid. One result is that rapidly changing gravitational fields can create particles from the vacuum, and in turn the backreaction on the gravitational dynamics operates like a damping force. I consider such effects in early universe cosmology and the theory of quantum black holes, including the possibility that the large-scale structure of the universe might be produced by quantum vacuum noise in an early inflationary phase. I also discuss the curious phenomenon that an observer who accelerates through a quantum vacuum perceives a bath of thermal radiation closely analogous to Hawking radiation from black holes, even though an inertial observer registers no particles. The effects predicted raise very deep and unresolved issues about the nature of quantum particles, the role of the observer, and the relationship between the quantum vacuum and the concepts of information and entropy. (c) 2001 American Institute of Physics.

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

NASA Astrophysics Data System (ADS)

Lachenmann, R.; Dirscherl, J.

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

Recycling of waste lead storage battery by vacuum methods.

PubMed

Lin, Deqiang; Qiu, Keqiang

2011-07-01

Waste lead storage battery is the most important recyclable lead material not only in various European and other OECD countries but also in China. Pollution control of lead has become the focus of people's attention in the world. A vacuum process for recycling waste lead storage battery was developed in this work. The experimental results showed that all the valuable materials in waste lead storage battery could be satisfactorily recycled by vacuum technologies. The vacuum melting of lead grids and the vacuum reduction of lead pastes produce the lead bullion with the direct recovery ratio of 96.29% and 98.98%, respectively. The vacuum pyrolysis of plastics can produce pyrolysis oil with yield of more than 93 wt.%. These vacuum recycling technologies offer improvements in metallurgical and environmental performance. Copyright © 2011 Elsevier Ltd. All rights reserved.

Window-assisted nanosphere lithography for vacuum micro-nano-electronics

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

Li, Nannan; Institute of Electronic Engineering, Chinese Academy of Engineering Physics, Mianyang, 621900; Pang, Shucai

2015-04-15

Development of vacuum micro-nano-electronics is quite important for combining the advantages of vacuum tubes and solid-state devices but limited by the prevailing fabricating techniques which are expensive, time consuming and low-throughput. In this work, window-assisted nanosphere lithography (NSL) technique was proposed and enabled the low-cost and high-efficiency fabrication of nanostructures for vacuum micro-nano-electronic devices, thus allowing potential applications in many areas. As a demonstration, we fabricated high-density field emitter arrays which can be used as cold cathodes in vacuum micro-nano-electronic devices by using the window-assisted NSL technique. The details of the fabricating process have been investigated. This work provided amore » new and feasible idea for fabricating nanostructure arrays for vacuum micro-nano-electronic devices, which would spawn the development of vacuum micro-nano-electronics.« less

Vacuum characteristics of the sucking cycle and relationships with milk removal from the breast in term infants.

PubMed

Cannon, Anna Maria; Sakalidis, Vanessa Susanna; Lai, Ching Tat; Perrella, Sharon Lisa; Geddes, Donna Tracy

2016-05-01

The importance of an infant's intra-oral vacuum in milk removal from the breast has been established. However, the relationship between the vacuum curve and milk transfer is not well understood. To investigate the parameters of the infant suck cycle in relation to the volume of milk removed from the breast. Cross-sectional study to elucidate the role of infant intra-oral vacuum in efficient milk removal from the breast. Nineteen fully breastfed term infants. Intra-oral vacuum was recorded during monitored breastfeeds using a pressure transducer. Ultrasound imaging (milk flow) and respiratory inductive plethysmography (swallowing) were used to determine the nutritive sucking (NS) portion of the feed. Milk intake was determined by weighing infants before and after feeds. Vacuum traces of the first and next 2min of NS from the first breast were analysed. The volumes of milk removed during both NS periods were negatively associated with peak vacuum (p<0.001) and rate of vacuum application (p<0.001), and positively related to area under first half of the suck cycle (p<0.001). Most parameters changed significantly from the first 2min of NS to the next 2min including significant reduction in peak vacuum and area under first half of the suck cycle. These results further support the role of intra-oral vacuum, specifically optimal peak vacuum, in effective and efficient milk removal during breastfeeding. It also appears that infants modify their sucking dynamics to adapt to changes in milk flow during milk ejection as the breast empties. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

14 CFR 29.1433 - Vacuum systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a.... (b) Each vacuum air system line and fitting on the discharge side of the pump that might contain...

21 CFR 884.5070 - Vacuum abortion system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

Velocity Plume Profiles for Hall Thrusters Using Laser Diagnostic

DTIC Science & Technology

2010-06-01

53 Collecting LIF Using Fiber Optics .............................................................................58 Vacuum ...54 Figure 40. Etalon Issue Through Vacuum Chamber Window [25]. ................................. 55 Figure 41. Collimator with Adapter in a...Methodology Facility Set-up Vacuum Chamber Testing took place within a vacuum chamber located at the AFIT Space Propulsion Analysis and System Simulation

7 CFR 58.217 - Evaporators and/or vacuum pans.

Code of Federal Regulations, 2011 CFR

2011-01-01

....217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers shall be equipped with an automatic condenser water level control, barometric leg, or so constructed so... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. When enclosed type condensers...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

46 CFR 153.368 - Pressure-vacuum valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

21 CFR 884.5070 - Vacuum abortion system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

21 CFR 884.5070 - Vacuum abortion system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

21 CFR 884.5070 - Vacuum abortion system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

21 CFR 884.5070 - Vacuum abortion system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

Vacuum Technology Considerations For Mass Metrology

PubMed Central

Abbott, Patrick J.; Jabour, Zeina J.

2011-01-01

Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology1 required for mass metrology and suggest procedures and hardware for successful and reproducible operation. PMID:26989593

Lightweight Tanks for Storing Liquefied Natural Gas

NASA Technical Reports Server (NTRS)

DeLay, Tom

2008-01-01

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

VACUUM TRAP

DOEpatents

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.

Determination of thermal contact conductance in vacuum-bagged thermoplastic prepreg stacks using infrared thermography

NASA Astrophysics Data System (ADS)

Baumard, Théo; De Almeida, Olivier; Menary, Gary; Le Maoult, Yannick; Schmidt, Fabrice; Bikard, Jérôme

2016-10-01

The infrared heating of a vacuum-bagged, thermoplastic prepreg stack of glass/PA66 was studied to investigate the influence of vacuum level on thermal contact resistance between plies. A higher vacuum level was shown experimentally to decrease the transverse heat transfer efficiency, indicating that considering only the effect of heat conduction at the plies interfaces is not sufficient to predict the temperature distribution. An inverse analysis was used to retrieve the contact resistance coefficients as a function of vacuum pressure.

Microfabricated triggered vacuum switch

DOEpatents

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.

Changes in CR-39 proton sensitivity due to prolonged exposure to high vacuums relevant to the National Ignition Facility and OMEGA.

PubMed

Manuel, M J-E; Rosenberg, M J; Sinenian, N; Rinderknecht, H; Zylstra, A B; Séguin, F H; Frenje, J; Li, C K; Petrasso, R D

2011-09-01

When used at facilities like OMEGA and the NIF, CR-39 is exposed to high vacuum environments before and after irradiation by charged particles and neutrons. Using an electrostatic linear accelerator at MIT, studies have been conducted to investigate the effects of high vacuum exposure on the sensitivity of CR-39 to fusion protons in the ~1-9 MeV energy range. High vacuum conditions, of order 10(-5) Torr, experienced by CR-39 samples at these facilities were emulated. It is shown that vacuum exposure times longer than ~16 h before proton irradiation result in a decrease in proton sensitivity, whereas no effect was observed for up to 67 h of vacuum exposure after proton irradiation. CR-39 sensitivity curves are presented for samples with prolonged exposure to high vacuum before and after proton irradiation. © 2011 American Institute of Physics

A large high vacuum, high pumping speed space simulation chamber for electric propulsion

NASA Technical Reports Server (NTRS)

Grisnik, Stanley P.; Parkes, James E.

1994-01-01

Testing high power electric propulsion devices poses unique requirements on space simulation facilities. Very high pumping speeds are required to maintain high vacuum levels while handling large volumes of exhaust products. These pumping speeds are significantly higher than those available in most existing vacuum facilities. There is also a requirement for relatively large vacuum chamber dimensions to minimize facility wall/thruster plume interactions and to accommodate far field plume diagnostic measurements. A 4.57 m (15 ft) diameter by 19.2 m (63 ft) long vacuum chamber at NASA Lewis Research Center is described. The chamber utilizes oil diffusion pumps in combination with cryopanels to achieve high vacuum pumping speeds at high vacuum levels. The facility is computer controlled for all phases of operation from start-up, through testing, to shutdown. The computer control system increases the utilization of the facility and reduces the manpower requirements needed for facility operations.

Developing a vacuum cooking equipment prototype to produce strawberry jam and optimization of vacuum cooking conditions.

PubMed

Okut, Dilara; Devseren, Esra; Koç, Mehmet; Ocak, Özgül Özdestan; Karataş, Haluk; Kaymak-Ertekin, Figen

2018-01-01

Purpose of this study was to develop prototype cooking equipment that can work at reduced pressure and to evaluate its performance for production of strawberry jam. The effect of vacuum cooking conditions on color soluble solid content, reducing sugars total sugars HMF and sensory properties were investigated. Also, the optimum vacuum cooking conditions for strawberry jam were optimized for Composite Rotatable Design. The optimum cooking temperature and time were determined targeting maximum soluble solid content and sensory attributes (consistency) and minimum Hue value and HMF content. The optimum vacuum cooking conditions determined were 74.4 °C temperature and 19.8 time. The soluble solid content strawberry jam made by vacuum process were similar to those prepared by traditional method. HMF contents of jams produced with vacuum cooking method were well within limit of standards.

Study on convection improvement of standard vacuum tube

NASA Astrophysics Data System (ADS)

He, J. H.; Du, W. P.; Qi, R. R.; He, J. X.

2017-11-01

For the standard all-glass vacuum tube collector, enhancing the vacuum tube axial natural convection can improve its thermal efficiency. According to the study of the standard all-glass vacuum tube, three kinds of guide plates which can inhibit the radial convection and increase axial natural convection are designed, and theory model is established. Experiments were carried out on vacuum tubes with three types of baffles and standard vacuum tubes without the improvement. The results show that T-type guide plate is better than that of Y-type guide plate on restraining convection and increasing axial radial convection effect, Y type is better than that of flat plate type, all guide plates are better than no change; the thermal efficiency of the tube was 2.6% higher than that of the unmodified standard vacuum tube. The efficiency of the system in the experiment can be increased by 3.1%.

Bakeout Chamber Within Vacuum Chamber

NASA Technical Reports Server (NTRS)

Taylor, Daniel M.; Soules, David M.; Barengoltz, Jack B.

1995-01-01

Vacuum-bakeout apparatus for decontaminating and measuring outgassing from pieces of equipment constructed by mounting bakeout chamber within conventional vacuum chamber. Upgrade cost effective: fabrication and installation of bakeout chamber simple, installation performed quickly and without major changes in older vacuum chamber, and provides quantitative data on outgassing from pieces of equipment placed in bakeout chamber.

Tubing vs. buckets: a cost comparison

Treesearch

Neil K. Huyler

1975-01-01

Equipment investment for tubing-vacuum systems was significantly less than that for bucket systems. Tubing-vacuum systems required about 22 percent less labor input, the major labor input being completed before sap-flow periods. Annual cost of operation was less for tubing-vacuum than the bucket system. Small tubing-vacuum operations showed more profit potential than...

Moving characteristics of electrodes for vacuum circuit breaker

NASA Astrophysics Data System (ADS)

Yuan, Shun; Wang, Jimei

1994-05-01

This paper analyzes the effect of the gap of electrodes on the state of vacuum arc by experiment and theory. And the model of vacuum arc is set up. The optimal gap can be deduced from controlling the vacuum arc to be diffusion state, in order to get the optimal moving characteristics of electrodes.

21 CFR 880.6740 - Vacuum-powered body fluid suction apparatus.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vacuum-powered body fluid suction apparatus. 880... Personal Use Miscellaneous Devices § 880.6740 Vacuum-powered body fluid suction apparatus. (a) Identification. A vacuum-powered body fluid suction apparatus is a device used to aspirate, remove, or sample...

21 CFR 880.6740 - Vacuum-powered body fluid suction apparatus.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vacuum-powered body fluid suction apparatus. 880... Personal Use Miscellaneous Devices § 880.6740 Vacuum-powered body fluid suction apparatus. (a) Identification. A vacuum-powered body fluid suction apparatus is a device used to aspirate, remove, or sample...

Researches on Position Detection for Vacuum Switch Electrode

NASA Astrophysics Data System (ADS)

Dong, Huajun; Guo, Yingjie; Li, Jie; Kong, Yihan

2018-03-01

Form and transformation character of vacuum arc is important influencing factor on the vacuum switch performance, and the dynamic separations of electrode is the chief effecting factor on the transformation of vacuum arcs forms. Consequently, how to detect the position of electrode to calculate the separations in the arcs image is of great significance. However, gray level distribution of vacuum arcs image isn’t even, the gray level of burning arcs is high, but the gray level of electrode is low, meanwhile, the forms of vacuum arcs changes sharply, the problems above restrict electrode position detection precisely. In this paper, algorithm of detecting electrode position base on vacuum arcs image was proposed. The digital image processing technology was used in vacuum switch arcs image analysis, the upper edge and lower edge were detected respectively, then linear fitting was done using the result of edge detection, the fitting result was the position of electrode, thus, accurate position detection of electrode was realized. From the experimental results, we can see that: algorithm described in this paper detected upper and lower edge of arcs successfully and the position of electrode was obtained through calculation.

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

NASA Astrophysics Data System (ADS)

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.

Carbon nanotube vacuum gauges with wide-dynamic range and processes thereof

NASA Technical Reports Server (NTRS)

Manohara, Harish (Inventor); Kaul, Anupama B. (Inventor)

2013-01-01

A miniature thermal conductivity gauge employs a carbon single-walled-nanotube. The gauge operates on the principle of thermal exchange between the voltage-biased nanotube and the surrounding gas at low levels of power and low temperatures to measure vacuum across a wide dynamic range. The gauge includes two terminals, a source of constant voltage to the terminals, a single-walled carbon nanotube between the terminals, a calibration of measured conductance of the nanotube to magnitudes of surrounding vacuum and a current meter in electrical communication with the source of constant voltage. Employment of the nanotube for measuring vacuum includes calibrating the electrical conductance of the nanotube to magnitudes of vacuum, exposing the nanotube to a vacuum, applying a constant voltage across the nanotube, measuring the electrical conductance of the nanotube in the vacuum with the constant voltage applied and converting the measured electrical conductance to the corresponding calibrated magnitude of vacuum using the calibration. The nanotube may be suspended to minimize heat dissipation through the substrate, increasing sensitivity at even tower pressures.

Vacuum mechatronics

NASA Technical Reports Server (NTRS)

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.

Robust Multilayer Insulation for Cryogenic Systems

NASA Technical Reports Server (NTRS)

Fesmire, J. E.; Scholtens, B. F.; Augustynowicz, S. D.

2007-01-01

New requirements for thermal insulation include robust Multilayer insulation (MU) systems that work for a range of environments from high vacuum to no vacuum. Improved MLI systems must be simple to install and maintain while meeting the life-cycle cost and thermal performance objectives. Performance of actual MLI systems has been previously shown to be much worse than ideal MLI. Spacecraft that must contain cryogens for both lunar service (high vacuum) and ground launch operations (no vacuum) are planned. Future cryogenic spacecraft for the soft vacuum environment of Mars are also envisioned. Industry products using robust MLI can benefit from improved cost-efficiency and system safety. Novel materials have been developed to operate as excellent thermal insulators at vacuum levels that are much less stringent than the absolute high vacuum requirement of current MLI systems. One such robust system, Layered Composite Insulation (LCI), has been developed by the Cryogenics Test Laboratory at NASA Kennedy Space Center. The experimental testing and development of LCI is the focus of this paper. LCI thermal performance under cryogenic conditions is shown to be six times better than MLI at soft vacuum and similar to MLI at high vacuum. The experimental apparent thermal conductivity (k-value) and heat flux data for LCI systems are compared with other MLI systems.

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

PubMed

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

2016-09-01

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

Ejector/liquid ring pump provides <0. 30 mm Hg vacuum for polymerization vessel

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

Lockwood, A.; Gaines, A.

1982-03-01

Firestone Fibers and Textiles Company, a division of Firestone Tire and Rubber Company, manufactures tire and industrial yarns of polyester and nylon-6. Nylon-6 molding and extrusion resins are also produced at the plant in Hopewell, Virginia. The process for making polyester requires an extremely low vacuum on the polymerization reactor. A consistent polymerization vessel vacuum of 0.3 mm Hg is needed, but the existing vacuum source, a five-stage steam jet ejector, could only provide a 0.5 mm Hg level. Two options were considered when the company decided to replace the original system with a system designed for 0.15 mm Hgmore » with a non-condensible gas load of 10.8 lb/hr. A new five-stage jet ejector system to meet these requirements would use 1395 lb/hr of 100 psig steam. The other option was a hybrid vacuum source composed of a three-stage steam ejector system and a liquid ring vacuum pump that is more energy efficient than ejectors for low vacuum applications. The hybrid system was selected because the three-stage jet ejector would use only 1240 lb/hr of 100 psig steam. The liquid ring vacuum pump would increase the material and installation cost of the system by about $4000, but the savings in steam consumption would pay back the added cost in less than two years. The jet ejector/liquid ring vacuum pump system has provided both the capacity and the extremely low vacuum needed for the polyester polymerization vessel, after making a small modification. The hybrid vacuum source is reliable, requires only routine maintenance, and will contiue to save substantial amounts of steam each year compared to the five-stage steam jet ejector.« less

Fast MRI-guided vacuum-assisted breast biopsy: initial experience.

PubMed

Liberman, Laura; Morris, Elizabeth A; Dershaw, D David; Thornton, Cynthia M; Van Zee, Kimberly J; Tan, Lee K

2003-11-01

The purpose of this study was to evaluate a new method for performing MRI-guided vacuum-assisted breast biopsy in a study of lesions that had subsequent surgical excision. SUBJECTS AND METHODS. Twenty women scheduled for MRI-guided needle localization and surgical biopsy were prospectively entered in the study. MRI-guided biopsy was performed with a vacuum-assisted probe, followed by placement of a localizing clip, and then needle localization for surgical excision. Vacuum-assisted biopsy and surgical histology were correlated. Vacuum-assisted biopsy was successfully performed in 19 (95%) of the 20 women. The median size of 27 MRI-detected lesions that had biopsy was 1.0 cm (range, 0.4-6.4 cm). Cancer was present in eight (30%) of 27 lesions and in six (32%) of 19 women; among these eight cancers, five were infiltrating and three were ductal carcinoma in situ (DCIS). Among these 27 lesions, histology was benign at vacuum-assisted biopsy and at surgery in 19 (70%), cancer at vacuum-assisted biopsy in six (22%), atypical ductal hyperplasia at vacuum-assisted biopsy and DCIS at surgery in one (4%), and benign at vacuum-assisted biopsy with surgery showing microscopic DCIS that was occult at MRI in one (4%). The median time to perform vacuum-assisted biopsy of a single lesion was 35 min (mean, 35 min; range, 24-48 min). Placement of a localizing clip, attempted in 26 lesions, was successful in 25 (96%) of 26, and the clip was retrieved on specimen radiography in 22 (96%) of 23. One complication occurred: a hematoma that resolved with compression. MRI-guided vacuum-assisted biopsy is a fast, safe, and accurate alternative to surgical biopsy for breast lesions detected on MRI.

Research on thermal conductivity of HGMs at vacuum in room temperature

NASA Astrophysics Data System (ADS)

Wang, Ping; Liao, Bin; An, Zhenguo; Yan, Kaiqi; Zhang, Jingjie

2018-05-01

Hollow glass microspheres (HGMs) can be used as thermal insulation materials owing to its hollow structure which brings excellent thermal insulation property and low density. At present, most researches on thermal conductivity of HGMs are focused on polymer matrix/HGMs composite materials. However, thermal conductivity of HGMs at vacuum in room temperature has rarely been investigated. In this work, thermal conductivity of six types of HGMs (T17 (0.17g/cm3), T20 (0.20g/cm3), T22 (0.22g/cm3), T25 (0.25g/cm3), T32 (0.32g/cm3) and T40 (0.40g/cm3)) at vacuum in room temperature were calculated by heat transfer of solid conduction and radiation. The calculation results showed that thermal conductivity of HGMs would be decreased by an order of magnitude compared with no vacuum. In order to verify the calculation and study vacuum thermal insulation properties of HGMs, thermal conductivity of above-mentioned HGMs at no vacuum and high vacuum in room temperature were measured by a self-made thermal conductivity measuring apparatus which was based on the transient plane source (TPS) method. The experimental results showed that thermal conductivity of HGMs were in the range of 4.2030E-02 to 6.3300E-02 W/m.K (at no vacuum) and 3.8160E-03 to 4.9660E-03 W/m.K (at high vacuum). The results indicated that experimental thermal conductivity was consistent with the calculation results and both of them were all decreased by 8-13 times at vacuum compared with no vacuum. In addition, the relationship with physical properties and thermal conductivity of HGMs has been discussed in detail. In conclusion, HGMs possess excellent thermal insulation performance at high vacuum in room temperature and have potential to further reduce thermal conductivity at the same conditions.

Development of a Modified Vacuum Cleaner for Lunar Surface Systems

NASA Technical Reports Server (NTRS)

Toon, Katherine P.; Lee, Steve A.; Edgerly, Rachel D.

2009-01-01

The National Aeronautics and Space Administration (NASA) mission to expand space exploration will return humans to the Moon with the goal of maintaining a long-term presence. One challenge that NASA will face returning to the Moon is managing the lunar regolith found on the Moon's surface, which will collect on extravehicular activity (EVA) suits and other equipment. Based on the Apollo experience, the issues astronauts encountered with lunar regolith included eye/lung irritation, and various hardware failures (seals, screw threads, electrical connectors and fabric contamination), which were all related to inadequate lunar regolith mitigation. A vacuum cleaner capable of detaching, transferring, and efficiently capturing lunar regolith has been proposed as a method to mitigate the lunar regolith problem in the habitable environment on lunar surface. In order to develop this vacuum, a modified "off-the-shelf" vacuum cleaner has been used to determine detachment efficiency, vacuum requirements, and optimal cleaning techniques to ensure efficient dust removal in habitable lunar surfaces, EVA spacesuits, and air exchange volume. During the initial development of the Lunar Surface System vacuum cleaner, systematic testing was performed with varying flow rates on multiple surfaces (fabrics and metallics), atmospheric (14.7 psia) and reduced pressures (10.2 and 8.3 psia), different vacuum tool attachments, and several vacuum cleaning techniques to determine the performance requirements for the vacuum cleaner. The data recorded during testing was evaluated by calculating percent removal, relative to the retained simulant on the tested surface. In addition, Scanning Electron Microscopy (SEM) imaging was used to determine particle size distribution retained on the surface. The scope of this paper is to explain the initial phase of vacuum cleaner development, including historical Apollo mission data, current state-of-the-art vacuum cleaner technology, and vacuum cleaner testing that has focused on detachment capabilities varying pressure environments.

Development of a Modified Vacuum Cleaner for Lunar Surface Systems

NASA Technical Reports Server (NTRS)

Toon, Katherine P.; Lee, Steve A.; Edgerly, Rachel D.

2010-01-01

The National Aeronautics and Space Administration (NASA) mission to expand space exploration will return humans to the Moon with the goal of maintaining a long-term presence. One challenge that NASA will face returning to the Moon is managing the lunar regolith found on the Moon's surface, which will collect on extravehicular activity (EVA) suits and other equipment. Based on the Apollo experience, the issues astronauts encountered with lunar regolith included eye/lung irritation, and various hardware failures (seals, screw threads, electrical connectors and fabric contamination), which were all related to inadequate lunar regolith mitigation. A vacuum cleaner capable of detaching, transferring, and efficiently capturing lunar regolith has been proposed as a method to mitigate the lunar regolith problem in the habitable environment on lunar surface. In order to develop this vacuum, a modified "off-the-shelf' vacuum cleaner will be used to determine detachment efficiency, vacuum requirements, and optimal cleaning techniques to ensure efficient dust removal in habitable lunar surfaces, EVA spacesuits, and air exchange volume. During the initial development of the Lunar Surface System vacuum cleaner, systematic testing was performed with varying flow rates on multiple surfaces (fabrics and metallics), atmospheric (14.7 psia) and reduced pressures (10.2 and 8.3 psia), different vacuum tool attachments, and several vacuum cleaning techniques in order to determine the performance requirements for the vacuum cleaner. The data recorded during testing was evaluated by calculating particulate removal, relative to the retained simulant on the tested surface. In addition, optical microscopy was used to determine particle size distribution retained on the surface. The scope of this paper is to explain the initial phase of vacuum cleaner development, including historical Apollo mission data, current state-of-the-art vacuum cleaner technology, and vacuum cleaner testing that has focused on detachment capabilities at varying pressure environments.

Dark matter as an effect of the quantum vacuum

NASA Astrophysics Data System (ADS)

Santos, Emilio

2018-04-01

The interaction between the quantum vacuum and a weak gravitational field is calculated for the vacuum fields of quantum electrodynamics. The result shows that the vacuum state is modified by the gravitational field, giving rise to a nonzero interaction energy. This suggests a model that fits in the main properties of the hypothetical dark matter in galactic haloes.

Resonant Circuits and Introduction to Vacuum Tubes, Industrial Electronics 2: 9325.03. Course Outline.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

The 135 clock-hour course for the 11th year consists of outlines for blocks of instruction on series resonant circuits, parallel resonant circuits, transformer theory and application, vacuum tube fundamentals, diode vacuum tubes, triode tube construction and parameters, vacuum tube tetrodes and pentodes, beam-power and multisection tubes, and…

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2013 CFR

2013-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2011 CFR

2011-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2012 CFR

2012-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2014 CFR

2014-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2010 CFR

2010-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... freely and does not remain in the open position. (c) A liquid filled pressure-vacuum breaker may be used... 46 Shipping 1 2014-10-01 2014-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... freely and does not remain in the open position. (c) A liquid filled pressure-vacuum breaker may be used... 46 Shipping 1 2013-10-01 2013-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

Scalar field vacuum expectation value induced by gravitational wave background

NASA Astrophysics Data System (ADS)

Jones, Preston; McDougall, Patrick; Ragsdale, Michael; Singleton, Douglas

2018-06-01

We show that a massless scalar field in a gravitational wave background can develop a non-zero vacuum expectation value. We draw comparisons to the generation of a non-zero vacuum expectation value for a scalar field in the Higgs mechanism and with the dynamical Casimir vacuum. We propose that this vacuum expectation value, generated by a gravitational wave, can be connected with particle production from gravitational waves and may have consequences for the early Universe where scalar fields are thought to play an important role.

Vacuum leak detector and method

DOEpatents

Edwards, Jr., David

1983-01-01

Apparatus and method for detecting leakage in a vacuum system involves a moisture trap chamber connected to the vacuum system and to a pressure gauge. Moisture in the trap chamber is captured by freezing or by a moisture adsorbent to reduce the residual water vapor pressure therein to a negligible amount. The pressure gauge is then read to determine whether the vacuum system is leaky. By directing a stream of carbon dioxide or helium at potentially leaky parts of the vacuum system, the apparatus can be used with supplemental means to locate leaks.

Ceramic vacuum tubes for geothermal well logging

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

Kelly, R.D.

1977-01-12

The results of investigations carried out into the availability and suitability of ceramic vacuum tubes for the development of logging tools for geothermal wells are summarized. Design data acquired in the evaluation of ceramic vacuum tubes for the development of a 500/sup 0/C instrumentation amplifier are presented. The general requirements for ceramic vacuum tubes for application to the development of high temperature well logs are discussed. Commercially available tubes are described and future contract activities that specifically relate to ceramic vacuum tubes are detailed. Supplemental data is presented in the appendix. (MHR)

An ultra-high vacuum chamber for scattering experiments featuring in-vacuum continuous in-plane variation of the angle between entrance and exit vacuum ports

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

Englund, Carl-Johan; Agåker, Marcus, E-mail: marcus.agaker@physics.uu.se; Fredriksson, Pierre

2015-09-15

A concept that enables in-vacuum continuous variation of the angle between two ports in one plane has been developed and implemented. The vacuum chamber allows for measuring scattering cross sections as a function of scattering angle and is intended for resonant inelastic X-ray scattering experiments. The angle between the ports can be varied in the range of 30°-150°, while the pressure change is less than 2 × 10{sup −10} mbars.

Method for sequentially processing a multi-level interconnect circuit in a vacuum chamber

NASA Technical Reports Server (NTRS)

Routh, D. E.; Sharma, G. C. (Inventor)

1984-01-01

An apparatus is disclosed which includes a vacuum system having a vacuum chamber in which wafers are processed on rotating turntables. The vacuum chamber is provided with an RF sputtering system and a dc magnetron sputtering system. A gas inlet introduces various gases to the vacuum chamber and creates various gas plasma during the sputtering steps. The rotating turntables insure that the respective wafers are present under the sputtering guns for an average amount of time such that consistency in sputtering and deposition is achieved. By continuous and sequential processing of the wafers in a common vacuum chamber without removal, the adverse affects of exposure to atmospheric conditions are eliminated providing higher quality circuit contacts and functional device.

Method for sequentially processing a multi-level interconnect circuit in a vacuum chamber

NASA Technical Reports Server (NTRS)

Routh, D. E.; Sharma, G. C. (Inventor)

1982-01-01

The processing of wafer devices to form multilevel interconnects for microelectronic circuits is described. The method is directed to performing the sequential steps of etching the via, removing the photo resist pattern, back sputtering the entire wafer surface and depositing the next layer of interconnect material under common vacuum conditions without exposure to atmospheric conditions. Apparatus for performing the method includes a vacuum system having a vacuum chamber in which wafers are processed on rotating turntables. The vacuum chamber is provided with an RF sputtering system and a DC magnetron sputtering system. A gas inlet is provided in the chamber for the introduction of various gases to the vacuum chamber and the creation of various gas plasma during the sputtering steps.

Effect of surface polishing and vacuum firing on electron stimulated desorption from 316LN stainless steel

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

Malyshev, Oleg B., E-mail: oleg.malyshev@stfc.ac.uk; Hogan, Benjamin T.; Pendleton, Mark

2014-09-01

The reduction of thermal outgassing from stainless steel by surface polishing or vacuum firing is well-known in vacuum technology, and the consequent use of both techniques allows an even further reduction of outgassing. The aim of this study was to identify the effectiveness of surface polishing and vacuum firing for reducing electron-stimulated desorption (ESD) from 316LN stainless steel, which is a frequently used material for particle accelerator vacuum chambers and components. It was found that, unlike for thermal outgassing, surface polishing does not reduce the ESD yield and may even increase it, while vacuum firing of nonpolished sample reduces onlymore » the H{sub 2} ESD yield by a factor 2.« less

Triggering vacuum capillaries for pneumatic pumping and metering liquids in point-of-care immunoassays.

PubMed

Weng, Kuo-Yao; Chou, Nien-Jen; Cheng, Jya-Wei

2008-07-01

An innovative vacuum capillary pneumatic actuation concept that can be used for point-of-care testing has been investigated. The vacuum glass capillaries are encapsulated within a laminated pouch and incorporated into the fluidic card. Vacuum glass capillaries broken by external force such as finger pressure, generate the pneumatic forces to induce liquid flow in the fluidic system. The sizes of vacuum capillary play a vital role in the pumping and metering functions of the system. The luteinizing hormone (LH) chromatographic immunoassay performances in the fluidic cards show consistency comparable to that obtained by manual micropipetting. The vacuum capillary pneumatic actuation will be applied in other complex handling step bioassays and lab-on-a-chip devices.

Method and apparatus for in-cell vacuuming of radiologically contaminated materials

DOEpatents

Spadaro, Peter R.; Smith, Jay E.; Speer, Elmer L.; Cecconi, Arnold L.

1987-01-01

A vacuum air flow operated cyclone separator arrangement for collecting, handling and packaging loose contaminated material in accordance with acceptable radiological and criticality control requirements. The vacuum air flow system includes a specially designed fail-safe prefilter installed upstream of the vacuum air flow power supply. The fail-safe prefilter provides in-cell vacuum system flow visualization and automatically reduces or shuts off the vacuum air flow in the event of an upstream prefilter failure. The system is effective for collecting and handling highly contaminated radiological waste in the form of dust, dirt, fuel element fines, metal chips and similar loose material in accordance with radiological and criticality control requirements for disposal by means of shipment and burial.

Vacuum delivery at The Maternity Hospital Kuala Lumpur: a comparison of metal and silicone cups.

PubMed

Lee, H Y; Subramaniam, N; Nordin, M M

1996-02-01

To compare the advantages and disadvantages of the New Bird metal cups and silicone cups in terms of maternal and foetal outcome. To study the adverse effects and factors associated with failed vacuum deliveries. A prospective randomised study of all vacuum deliveries from 1 December 1991 to 31 April 1992. The Hanshin electrical vacuum pump was used. A large obstetric unit-The Maternity Hospital Kuala Lumpur (MHKL). Seventy-two consecutive patients where vacuum deliveries were indicated. Forty had metal and 32 had silicone cups. Another 7 vacuum deliveries using the manual vacuum pump were excluded. Success rate of vaginal delivery, birth canal injuries, post-partum haemorrhage, duration of hospital stay, Apgar score, foetal injuries (scalp-ecchymosis, haematomas) neonatal jaundice, the rate of special care nursery (SCN) admission and neonatal mortality rate. Failure to deliver with silicone cups alone was 21.9% compared to 10% for metal cups alone. Material morbidities and serious foetal scalp injuries were almost the same in both cups. However, minor foetal scalp injuries were significantly lower with silicone cups. Maternal height and baby's weight had no independent predictive values for successful vacuum delivery. When the foetal head was palpable per abdomen, the failure rate was 54.5% compared to 8.2% when it was not. Failed vacuum deliveries were associated with increased maternal and foetal morbidities. Silicone cups and metal cups can be equally dangerous to the baby. Although our sample size was small, we recommend that vacuum delivery be avoided if the foetal head is palpable per abdomen.

Vacuum cleaner emissions as a source of indoor exposure to airborne particles and bacteria.

PubMed

Knibbs, Luke D; He, Congrong; Duchaine, Caroline; Morawska, Lidia

2012-01-03

Vacuuming can be a source of indoor exposure to biological and nonbiological aerosols, although there are few data that describe the magnitude of emissions from the vacuum cleaner itself. We therefore sought to quantify emission rates of particles and bacteria from a large group of vacuum cleaners and investigate their potential determinants, including temperature, dust bags, exhaust filters, price, and age. Emissions of particles between 0.009 and 20 μm and bacteria were measured from 21 vacuums. Ultrafine (<100 nm) particle emission rates ranged from 4.0 × 10(6) to 1.1 × 10(11) particles min(-1). Emission of 0.54-20 μm particles ranged from 4.0 × 10(4) to 1.2 × 10(9) particles min(-1). PM(2.5) emissions were between 2.4 × 10(-1) and 5.4 × 10(3) μg min(-1). Bacteria emissions ranged from 0 to 7.4 × 10(5) bacteria min(-1) and were poorly correlated with dust bag bacteria content and particle emissions. Large variability in emission of all parameters was observed across the 21 vacuums, which was largely not attributable to the range of determinant factors we assessed. Vacuum cleaner emissions contribute to indoor exposure to nonbiological and biological aerosols when vacuuming, and this may vary markedly depending on the vacuum used.

Multipurpose Vacuum Induction Processing System

NASA Astrophysics Data System (ADS)

Govindaraju, M.; Kulkarni, Deepak; Balasubramanian, K.

2012-11-01

Multipurpose vacuum processing systems are cost effective; occupy less space, multiple functional under one roof and user friendly. A multipurpose vacuum induction system was designed, fabricated and installed in a record time of 6 months time at NFTDC Hyderabad. It was designed to function as a) vacuum induction melting/refining of oxygen free electronic copper/pure metals, b) vacuum induction melting furnace for ferrous materials c) vacuum induction melting for non ferrous materials d) large vacuum heat treatment chamber by resistance heating (by detachable coil and hot zone) e) bottom discharge vacuum induction melting system for non ferrous materials f) Induction heat treatment system and g) directional solidification /investment casting. It contains provision for future capacity addition. The attachments require to manufacture multiple shaped castings and continuous rod casting can be added whenever need arises. Present capacity is decided on the requirement for 10years of development path; presently it has 1.2 ton liquid copper handling capacity. It is equipped with provision for capacity addition up to 2 ton liquid copper handling capacity in future. Provision is made to carry out the capacity addition in easy steps quickly. For easy operational maintenance and troubleshooting, design was made in easily detachable sections. High vacuum system is also is detachable, independent and easily movable which is first of its kind in the country. Detailed design parameters, advantages and development history are presented in this paper.

Vacuum transfer system increases sugar maple sap yield

Treesearch

Russell S. Walters

1978-01-01

Yields of sugar maple sap collected from three plastic pipeline systems by gravity, vacuum pump, and a vacuum pump with a transfer tank were compared during 2 years in northern Vermont. The transfer system yielded 27 percent more sap one year and 17 percent more the next year. Higher vacuum levels at the tapholes were observed in the transfer system.

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

Code of Federal Regulations, 2011 CFR

2011-10-01

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

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

Code of Federal Regulations, 2014 CFR

2014-10-01

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

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

Code of Federal Regulations, 2010 CFR

2010-10-01

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

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

Code of Federal Regulations, 2012 CFR

2012-10-01

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

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

Code of Federal Regulations, 2013 CFR

2013-10-01

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

Comparison of vacuum and gravity sap flows from paired sugar maple trees

Treesearch

H. Clay Smith; Carter B. Gibbs

1970-01-01

Paired sugar maple trees with single tapholes were used to compare sap yields from vacuum-pumping with sap yields from gravity flow. Results indicated that vacuum yields were approximately twice as great as gravity flows. These results support previous findings from studies in which vacuum and gravity were compared with two tapholes on the same tree.

Effect of vacuum roasting on acrylamide formation and reduction in coffee beans.

PubMed

Anese, Monica; Nicoli, Maria Cristina; Verardo, Giancarlo; Munari, Marina; Mirolo, Giorgio; Bortolomeazzi, Renzo

2014-02-15

Coffea arabica beans were roasted in an oven at 200 °C for increasing lengths of time under vacuum (i.e. 0.15 kPa). The samples were then analysed for colour, weight loss, acrylamide concentration and sensory properties. Data were compared with those obtained from coffee roasted at atmospheric pressure (i.e. conventional roasting), as well as at atmospheric pressure for 10 min followed by vacuum treatment (0.15 kPa; i.e. conventional-vacuum roasting). To compare the different treatments, weight loss, colour and acrylamide changes were expressed as a function of the thermal effect received by the coffee beans during the different roasting processes. Vacuum-processed coffee with medium roast degree had approximately 50% less acrylamide than its conventionally roasted counterpart. It was inferred that the low pressure generated inside the oven during the vacuum process exerted a stripping effect preventing acrylamide from being accumulated. Vacuum-processed coffee showed similar colour and sensory properties to conventionally roasted coffee. Copyright © 2013 Elsevier Ltd. All rights reserved.

A highly miniaturized vacuum package for a trapped ion atomic clock

DOE PAGES

Schwindt, Peter D. D.; Jau, Yuan-Yu; Partner, Heather; ...

2016-05-12

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

Double Vacuum Bag Process for Resin Matrix Composite Manufacturing

NASA Technical Reports Server (NTRS)

Hou, Tan-Hung (Inventor); Jensen, Brian J. (Inventor)

2007-01-01

A double vacuum bag molding assembly with improved void management and laminate net shape control which provides a double vacuum enviromnent for use in fabricating composites from prepregs containing air and/or volatiles such as reactive resin matrix composites or composites from solvent containing prepregs with non-reactive resins matrices. By using two vacuum environments during the curing process, a vacuum can be drawn during a B-stage of a two-step cycle without placing the composite under significant relative pressure. During the final cure stage, a significant pressure can be applied by releasing the vacuum in one of the two environments. Inner and outer bags are useful for creating the two vacuum environments with a perforated tool intermediate the two. The composite is placed intermediate a tool plate and a caul plate in the first environment with the inner bag and tool plate defining the first environment. The second environment is characterized by the outer bag which is placed over the inner bag and the tool plate.

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

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

Fiber Bragg grating sensors for real-time monitoring of evacuation process

NASA Astrophysics Data System (ADS)

Guru Prasad, A. S.; Hegde, Gopalkrishna M.; Asokan, S.

2010-03-01

Fiber bragg grating (FBG) sensors have been widely used for number of sensing applications like temperature, pressure, acousto-ultrasonic, static and dynamic strain, refractive index change measurements and so on. Present work demonstrates the use of FBG sensors in in-situ measurement of vacuum process with simultaneous leak detection capability. Experiments were conducted in a bell jar vacuum chamber facilitated with conventional Pirani gauge for vacuum measurement. Three different experiments have been conducted to validate the performance of FBG sensor in monitoring vacuum creating process and air bleeding. The preliminary results of FBG sensors in vacuum monitoring have been compared with that of commercial Pirani gauge sensor. This novel technique offers a simple alternative to conventional method for real time monitoring of evacuation process. Proposed FBG based vacuum sensor has potential applications in vacuum systems involving hazardous environment such as chemical and gas plants, automobile industries, aeronautical establishments and leak monitoring in process industries, where the electrical or MEMS based sensors are prone to explosion and corrosion.

Preparation of Mirror Coatings for the Vacuum Ultraviolet in a 2-m Evaporator.

PubMed

Bradford, A P; Hass, G; Osantowski, J F; Toft, A R

1969-06-01

The design and features of a 2-m evaporator suitable for coating large mirrors uniformly with Al + MgF(2) and Al + LiF films of high reflectance in the vacuum uv are described. The techniques used for monitoring film thicknesses during the film deposition and for producing films of uniform thicknesses over large areas are discussed. It is shown that the Al films for MgF(2)_ and LiF-protected mirrors of highest reflectance in the vacuum uv down to 1000 A should be 700-800 A thick. Data on the vacuum uv reflectance of Al coated with MgF(2) films of various thicknesses are presented. It was found that mirror coatings prepared in a large evaporator have a higher reflectance in the vacuum uv than those deposited under the same vacuum and deposition conditions in a small vacuum unit. At lambda = 1216 A, the reflectance of Al overcoated with 250 A of MgF(2) was measured to be about 85%.

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

PubMed

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

2011-01-01

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

A novel dehydration technique for carrot slices implementing ultrasound and vacuum drying methods.

PubMed

Chen, Zhi-Gang; Guo, Xiao-Yu; Wu, Tao

2016-05-01

A novel drying technique using a combination of ultrasound and vacuum dehydration was developed to shorten the drying time and improve the quality of carrot slices. Carrot slices were dried with ultrasonic vacuum (USV) drying and vacuum drying at 65 °C and 75 °C. The drying rate was significantly influenced by the drying techniques and temperatures. Compared with vacuum drying, USV drying resulted in a 41-53% decrease in the drying time. The drying time for the USV and vacuum drying techniques at 75 °C was determined to be 140 and 340 min for carrot slices, respectively. The rehydration potential, nutritional value (retention of β-carotene and ascorbic acid), color, and textural properties of USV-dried carrot slices are predominately better compared to vacuum-dried carrot slices. Moreover, lower energy consumption was used in the USV technique. The drying data (time versus moisture ratio) were successfully fitted to Wang and Singh model. Copyright © 2015. Published by Elsevier B.V.

Wireless Integrated Microelectronic Vacuum Sensor System

NASA Technical Reports Server (NTRS)

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

2013-01-01

NASA Stennis Space Center's (SSC's) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer. A vacuum jacketed pipe is essentially two pipes in one. There is an inner carrier pipe, in which the cryogenic liquid is actually transferred, and an outer jacket pipe that supports and seals the vacuum insulation, forming the "vacuum jacket." The integrity of the vacuum jacketed transmission lines that transfer the cryogenic fluid from delivery barges to the test stand must be maintained prior to and during engine testing. To monitor the vacuum in these vacuum jacketed transmission lines, vacuum gauge readings are used. At SSC, vacuum gauge measurements are done on a manual rotation basis with two technicians, each using a handheld instrument. Manual collection of vacuum data is labor intensive and uses valuable personnel time. Additionally, there are times when personnel cannot collect the data in a timely fashion (i.e., when a leak is detected, measurements must be taken more often). Additionally, distribution of this data to all interested parties can be cumbersome. To simplify the vacuum-gauge data collection process, automate the data collection, and decrease the labor costs associated with acquiring these measurements, an automated system that monitors the existing gauges was developed by Invocon, Inc. For this project, Invocon developed a Wireless Integrated Microelectronic Vacuum Sensor System (WIMVSS) that provides the ability to gather vacuum-gauge measurements automatically and wirelessly, in near-real time - using a low-maintenance, lowpower sensor mesh network. The WIMVSS operates by using a self-configuring mesh network of wireless sensor units. Mesh networking is a type of networking where each sensor or node can capture and disseminate its own data, but also serve as a relay to receive and transmit data from other sensors. Each sensor node can synchronize with adjacent sensors, and propagate data from one sensor to the next, until the destination is reached. In this case, the destination is a Network Interface Unit (NIU). The WIMVSS sensors are mounted on the existing vacuum gauges. Information gathered by the sensors is sent to the NIU. Because of the mesh networking, if a sensor cannot directly send the data to the NIU, it can be propagated through the network of sensors. The NIU requires antenna access to the sensor units, AC power, and an Ethernet connection. The NIU bridges the sensor network to a WIMVSS server via an Ethernet connection. The server is configured with a database, a Web server, and proprietary interface software that makes it possible for the vacuum measurements from vacuum jacketed fluid lines to be saved, retrieved, and then displayed from any Web-enabled PC that has access to the Internet. Authorized users can then simply access the data from any PC with Internet connection. Commands can also be sent directly from the Web interface for control and maintenance of the sensor network. The technology enabled by the WIMVSS decreases labor required for gathering vacuum measurements, increases access to vacuum data by making it available on any computer with access to the Internet, increases the frequency with which data points can be acquired for evaluating the system, and decreases the recurring cost of the sensors by using off-the-shelf components and integrating these with heritage vacuum gauges.

Vacuum chamber-free centrifuge with magnetic bearings.

PubMed

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

2013-09-01

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

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, J.D.

1993-11-09

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of standard polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, J.D.

1995-03-07

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Main Vacuum Technical Issues of Evacuated Tube Transportation

NASA Astrophysics Data System (ADS)

Zhang, Y. P.; Li, S. S.; Wang, M. X.

In the future, Evacuated Tube Transportation (ETT) would be built and faster than jets. ETT tube with diameter 2∼4m and length over 1000 km will be the largest scale vacuum equipment on earth. This paper listed some main vacuum technical issues to be solved in ETT as follow. How to build ultra-large-scale vacuum chamber like ETT tube with low cost and high reliability? How to pump gas out off the ETT tube in short time? How to release heat or reduce temperature in the vacuum tube? Hot to avoid vacuum electricity discharge? How to manufacture vehicles with airproof shells and equip the life support system? How to detect leakage and find leakage position efficiently and fast as possible? Some relative solutions and suggestions are put up.

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, John D.

1993-01-01

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Vacuum deposition and curing of liquid monomers apparatus

DOEpatents

Affinito, John D.

1996-01-01

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Vacuum deposition and curing of liquid monomers

DOEpatents

Affinito, John D.

1995-01-01

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

Refrigerated cryogenic envelope

DOEpatents

Loudon, John D.

1976-11-16

An elongated cryogenic envelope including an outer tube and an inner tube coaxially spaced within said inner tube so that the space therebetween forms a vacuum chamber for holding a vacuum. The inner and outer tubes are provided with means for expanding or contracting during thermal changes. A shield is located in the vacuum chamber intermediate the inner and outer tubes; and, a refrigeration tube for directing refrigeration to the shield is coiled about at least a portion of the inner tube within the vacuum chamber to permit the refrigeration tube to expand or contract along its length during thermal changes within said vacuum chamber.

Radiation force on a single atom in a cavity

NASA Technical Reports Server (NTRS)

Kim, M. S.

1992-01-01

We consider the radiation pressure microscopically. Two perfectly conducting plates are parallelly placed in a vacuum. As the vacuum field hits the plates they get pressure from the vacuum. The excessive outside modes of the vacuum field push the plates together, which is known as the Casimer force. We investigate the quantization of the standing wave between the plates to study the interaction between this wave and the atoms on the plates or between the plates. We show that even the vacuum field pushes the atom to place it at nodes of the standing wave.

Metal vapor vacuum arc switching - Applications and results. [for launchers

NASA Technical Reports Server (NTRS)

Cope, D.; Mongeau, P.

1984-01-01

The design of metal-vapor vacuum-arc switches (MVSs) for electromagnetic launchers is discussed, and preliminary results are presented for an experimental MVS. The general principles of triggered-vacuum-gap and vacuum-interrupter MVSs are reviewed, and the requirements of electromagnetic launchers are analyzed. High-current design problems such as electrode erosion, current sharing, magnetic effects, and thermal effects are examined. The experimental MVS employs stainless-steel flanges, a glass vacuum vessel, an adjustable electrode gap, autonomous internal magnetic-field coils, and a tungsten-pin trigger assembly. Some results from tests without magnetic augmentation are presented graphically.

Vacuum probe surface sampler

NASA Technical Reports Server (NTRS)

Zahlava, B. A. (Inventor)

1973-01-01

A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacuum source is frictionally attached to a cone assembly terminating in a flared tip adapted to be passed over the surface to be sampled. A fine mesh screen carried by the vacuum head provides support for a membrane filter which collects the microorganisms or other particles. The head assembly is easily removed from the cone assembly without contacting the cone assembly with human hands.

Vacuum fluctuations of the supersymmetric field in curved background

NASA Astrophysics Data System (ADS)

Bilić, Neven; Domazet, Silvije; Guberina, Branko

2012-01-01

We study a supersymmetric model in curved background spacetime. We calculate the effective action and the vacuum expectation value of the energy momentum tensor using a covariant regularization procedure. A soft supersymmetry breaking induces a nonzero contribution to the vacuum energy density and pressure. Assuming the presence of a cosmic fluid in addition to the vacuum fluctuations of the supersymmetric field an effective equation of state is derived in a self-consistent approach at one loop order. The net effect of the vacuum fluctuations of the supersymmetric fields in the leading adiabatic order is a renormalization of the Newton and cosmological constants.

Quantum Mechanics, vacuum, particles, Gödel-Cohen incompleteness and the Universe

NASA Astrophysics Data System (ADS)

Gonzalez-Mestres, Luis

2017-12-01

Are the standard laws of Physics really fundamental principles? Does the physical vacuum have a more primordial internal structure? Are quarks, leptons, gauge bosons… ultimate elementary objects? These three basic questions are actually closely related. If the deep vacuum structure and dynamics turn out to be less trivial than usually depicted, the conventional "elementary" particles will most likely be excitations of such a vacuum dynamics that remains by now unknown. We then expect relativity and quantum mechanics to be low-energy limits of a more fundamental dynamical pattern that generates them at a deeper level. It may even happen that vacuum drives the expansion of the Universe from its own inner dynamics. Inside such a vacuum structure, the speed of light would not be the critical speed for vacuum constituents and propagating signals. The natural scenario would be the superbradyon (superluminal preon) pattern we postulated in 1995, with a new critical speed cs much larger than the speed of light c just as c is much larger than the speed of sound. Superbradyons are assumed to be the bradyons of a super-relativity associated to cs (a Lorentz invariance with cs as the critical speed). Similarly, the standard relativistic space-time with four real coordinates would not necessarily hold beyond low-energy and comparatively local distance scales. Instead, the spinorial space-time (SST) with two complex coordinates we introduced in 1996-97 may be the suitable one to describe the internal structure of vacuum and standard "elementary" particles and, simultaneously, Cosmology at very large distance scales. If the constituents of the preonic vacuum are superluminal, quantum entanglement appears as a natural property provided cs ≫ c . The value of cs can even be possibly found experimentally by studying entanglement at large distances. It is not excluded that preonic constituents of vacuum can exist in our Universe as free particles ("free" superbradyons), in which case we expect them to be weakly coupled to standard matter. If a preonic vacuum is actually leading the basic dynamics of Particle Physics and Cosmology, and standard particles are vacuum excitations, the Gödel-Cohen incompleteness will apply to vacuum dynamics whereas the conventional laws of physics will actually be approximate and have error bars. We discuss here the possible role of the superbradyonic vacuum and of the SST in generating Quantum Mechanics, as well as the implications of such a dynamical origin of the conventional laws of Physics and possible evidences in experiments and observations. Black holes, gravitational waves, possible "free" superbradyons or preonic waves, unconventional vacuum radiation… are considered from this point of view paying particular attention to LIGO, VIRGO and CERN experiments. This lecture is dedicated to the memory of John Bell

Vacuum casting of thick polymeric films

NASA Technical Reports Server (NTRS)

Cuddihy, E. F.; Moacanin, J.

1979-01-01

Bubble formation and layering, which often plague vacuum-evaporated films, are prevented by properly regulating process parameters. Vacuum casting may be applicable to forming thick films of other polymer/solvent solutions.

14 CFR 25.1433 - Vacuum systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. [Doc. No...

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

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

FOERSTER,C.

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

Vacuum collection of Douglas-fir pollen for supplemental mass pollinations.

Treesearch

D.L. Copes; N.C. Vance; W.K. Randall; A. Jasumback; R. Hallman

1991-01-01

An Aget Cyclone dust collector and peripheral equipment were fieldtested for use in vacuuming large quantities of pollen from 30- to 40-foot trees in a Douglas-fir seed orchard. The Cyclone machine (Model 20SN31P) operated without a vacuum bag or filter device, so no blockage or reduction in vacuum efficiency occurred when large volumes of pollen were collected....

Ceramic vacuum tubes for geothermal well logging

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

Kelly, R.D.

1977-01-01

Useful design data acquired in the evaluation of ceramic vacuum tubes for the development of a 500/sup 0/C instrumentation amplifier are presented. The general requirements for ceramic vacuum tubes are discussed for application to the development of high temperature well logs. Commercially available tubes are described and future contract activities that specifically relate to ceramic vacuum tubes are detailed. Supplemental data are presented in the appendix.

92. VIEW OF PRECIPITATION AREA FROM SOUTHWEST. VACUUM CLARIFIER TANK ...

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

92. VIEW OF PRECIPITATION AREA FROM SOUTHWEST. VACUUM CLARIFIER TANK No. 1 AT LOWER LEFT, UNDER LAUNDER FEED TO GOLD TANK No. 2, AND VACUUM CLARIFIER TANK No. 2, AT MIDRIGHT. VACUUM RECEIVER TANK ON UPPER LEFT. PIPE TO TOP CENTER OF TANK TAKES OUTFLOW FROM CLARIFIER LEAVES. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

Vacuum frying as a route to produce novel snacks with desired quality attributes according to new health trends.

PubMed

Dueik, V; Bouchon, P

2011-03-01

Consumers look for products that contribute to their wellness and health, however, even health-conscious consumers are not willing to sacrifice organoleptic properties, and intense full-flavor snacks remain an important trend. The objective of this study was to examine most important quality parameters of vacuum (1.92 inHg) and atmospheric-fried carrot, potato, and apple slices to determine specific advantages of vacuum technology. Slices were fried using equivalent thermal driving forces, maintaining a constant difference between oil temperature and the boiling point of water at the working pressure (ΔT = 60 and 80 °C). This resulted in frying temperatures of 160 and 180 °C, and 98 and 118 °C, for atmospheric and vacuum frying, respectively. Vacuum-fried carrot and potato chips absorbed about 50% less oil than atmospheric-fried chips, whereas vacuum-fried apple chips reduced oil absorption by 25%. Total carotenoids and ascorbic acid (AA) were greatly preserved during vacuum frying. Carrot chips vacuum fried at 98 °C retained about 90% of total carotenoids, whereas potato and apple slices vacuum fried at 98 °C, preserved around 95% of their initial AA content. Interestingly, results showed that the antioxidant capacity of chips may be related to both the presence of natural antioxidants and brown pigments developed at elevated temperatures. A way to reduce detrimental effects of deep-fat frying is through operating-pressure reduction, the essence behind vacuum deep-fat frying. In this way, it is possible to remove product moisture at a low temperature in a low-oxygen environment. The objective of this research was to study the effect of oil temperature reduction when vacuum frying traditional (potatoes) and nontraditional products (carrots and apples) on most important quality attributes (vitamins, color, and oil uptake). Results are promising and show that vacuum frying can be an alternative to produce nutritious and novel snacks with desired quality attributes, since vitamins and color were greatly preserved and oil absorption could be substantially reduced.

Optimal application of the Contura multilumen balloon breast brachytherapy catheter vacuum port to deliver accelerated partial breast irradiation.

PubMed

Tokita, Kenneth M; Cuttino, Laurie W; Vicini, Frank A; Arthur, Douglas W; Todor, Dorin A; Julian, Thomas B; Lyden, Maureen R

2011-01-01

The impact of using the Contura multilumen balloon (MLB) (SenoRx, Inc., Irvine, CA) breast brachytherapy catheter's vacuum port in patients treated with accelerated partial breast irradiation (APBI) was analyzed. Data from 32 patients at two sites were reviewed. Variables analyzed included the seroma fluid (SF):air volume around the MLB before and after vacuum port use and on its ability to improve (1) the eligibility of patients for APBI and (2) dose coverage of the planning target volume for evaluation (PTV_EVAL) in eligible patients. The median SF/air volume before vacuum removal was 6.8 cc vs. 0.8 cc after vacuum removal (median reduction in SF/air volume was 90.5%). Before vacuum port use, the median SF/air volume expressed as percentage of the PTV_EVAL was 7.8% (range, 1.9-26.6) in all patients. After application of the vacuum, this was reduced to 1.2%. Before vacuum port use, 10 (31.3%) patients were not considered acceptable candidates for APBI because the SF/air volume:PTV_EVAL ratio (SF:PTV) was greater than 10% (range, 10.1-26.6%; median, 15.2%). After vacuum port use, the median SF:PTV ratio was 1.6% for a median reduction of 91.5%. In addition, the percentage of the prescribed dose covering greater than or equal to 90% of the PTV_EVAL proportionally increased a median of 8% (range, 3-10%) in eligible patients. Use of the Contura MLB vacuum port significantly improved the conformity of the target tissue to the balloon surface, leading to reproducible dose delivery and increased target volume coverage. In addition, application of the vacuum allowed the safe treatment of unacceptable patients with APBI. Copyright © 2011 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Numerical modeling of high-voltage circuit breaker arcs and their interraction with the power system

NASA Astrophysics Data System (ADS)

Orama, Lionel R.

In this work the interaction between series connected gas and vacuum circuit breaker arcs has been studied. The breakdown phenomena in vacuum interrupters during the post arc current period have been of special interest. Numerical models of gas and vacuum arcs were developed in the form of black box models. Especially, the vacuum post arc model was implemented by combining the existing transition model with an ion density function and expressions for the breakdown mechanisms. The test series studied reflect that for electric fields on the order of 10sp7V/m over the anode, the breakdown of the vacuum gap can result from a combination of both thermal and electrical stresses. For a particular vacuum device, the vacuum model helps to find the interruption limits of the electric field and power density over the anode. The series connection of gas and vacuum interrupters always performs better than the single gas device. Moreover, to take advantage of the good characteristics of both devices, the time between the current zero crossing in each interrupter can be changed. This current zero synchronization is controlled by changing the capacitance in parallel to the gas device. This gas/vacuum interrupter is suitable for interruption of very stressful short circuits in which the product of the dI/dt before current zero and the dV/dt after current zero is very high. Also, a single SF6 interrupter can be replaced by an air circuit breaker of the same voltage rating in series with a vacuum device without compromising the good performance of the SF6 device. Conceptually, a series connected vacuum device can be used for high voltage applications with equal distribution of electrical stresses between the individual interrupters. The equalization can be made by a sequential opening of the individual contact pairs, beginning with the interruptors that are closer to ground potential. This could eliminate the use of grading capacitors.

Axial bone-socket displacement for persons with a traumatic transtibial amputation: The effect of elevated vacuum suspension at progressive body-weight loads.

PubMed

Darter, Benjamin J; Sinitski, Kirill; Wilken, Jason M

2016-10-01

Elevated vacuum suspension systems use a pump to draw air from the socket with the intent of reducing bone-socket motion as compared to passive suction systems. However, it remains unknown if elevated vacuum suspension systems decrease limb displacement uniformly during transitions from unloaded to full-body-weight support. To compare limb-socket motion between elevated vacuum and passive suction suspension sockets using a controlled loading paradigm. Comparative analysis. Persons with transtibial amputation were assessed while wearing either an elevated vacuum or passive suction suspension socket. Digital video fluoroscopy was used to measure axial bone-socket motion while the limb was loaded in 20% body-weight increments. An analysis of variance model was used to compare between suspension types. Total axial displacement (0%-100% body weight) was significantly lower using the elevated vacuum (vacuum: 1.3 cm, passive suction: 1.8 cm; p < 0.0001). Total displacement decreased primarily due to decreased motion during initial loading (0%-20%; p < 0.0001). Other body-weight intervals were not significantly different between systems. Elevated vacuum suspension reduced axial limb-socket motion by maintaining position of the limb within the socket during unloaded conditions. Elevated vacuum provided no meaningful improvement in limb-socket motion past initial loading. Excessive bone-socket motion contributes to poor residual limb health. Our results suggest elevated vacuum suspensions can reduce this axial displacement. Visual assessment of the images suggests that this occurs through the reduction or elimination of the air pocket between the liner and socket wall while the limb is unloaded. © The International Society for Prosthetics and Orthotics 2015.

Traction force during vacuum extraction: a prospective observational study.

PubMed

Pettersson, K; Ajne, J; Yousaf, K; Sturm, D; Westgren, M; Ajne, G

2015-12-01

To investigate the traction force employed during vacuum extractions. Observational cross-sectional study. Obstetric Department, Karolinska University Hospital, Sweden, and the Swedish National Congress of Obstetrics and Gynaecology, 2013. Two hundred women with vacuum extraction at term and 130 obstetricians participating in a simulated setting. In a normal clinical setting, we used a specially adapted device to measure and record the force used to undertake vacuum extraction. In a subsequent part of the study, the force employed for vacuum extraction by a group of obstetricians in a fictive setting was estimated and objectively measured. Applied force during vacuum extraction in relation to the estimated level of difficulty in the delivery; perinatal diagnoses of asphyxia or head trauma; estimated force compared with objectively measured force employed in the fictive setting. The median (minimum-maximum) peak forces for minimum, average and excessive vacuum extraction in the clinical setting were 176 N (5-360 N), 225 N (115-436 N), and 241 N (164-452 N), respectively. In 34% of cases a force in excess of 216 N was employed. There was no correlation between the umbilical arterial pH at delivery and the traction force employed during extraction. Four cases of mild hypoxic ischaemic encephalopathy were observed, three of which were associated with a delivery whereby excessive traction force was employed during the vacuum extraction. In the fictive setting, the actual exerted force was twice the quantitative estimation. The measured forces in the clinical setting were four times higher than that estimated in the fictive setting. Higher than expected levels of traction force were used for vacuum extraction delivery. As obstetricians tend to underestimate the force applied during vacuum extraction, objective measurement with instantaneous feedback may be valuable in raising awareness. © 2015 Royal College of Obstetricians and Gynaecologists.

PREFACE: International Symposium on `Vacuum Science and Technology' (IVS 2007)

NASA Astrophysics Data System (ADS)

Mittal, K. C.; Gupta, S. K.

2008-03-01

The Indian Vacuum Society (established in 1970) has organized a symposium every alternate year on various aspects of vacuum science and technology. There has been considerable participation from R & D establishments, universities and Indian industry in this event. In view of the current global scenario and emerging trends in vacuum technology, this year, the executive committee of IVS felt it appropriate to organize an international symposium at Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 from 29-30 November 2007. This symposium provided a forum for exchange of information among vacuum scientists, technologists and industrialists on recent advances made in the areas of large vacuum systems, vacuum production, its measurement and applications in industry, and material processing in vacuum. Vacuum science and technology has made vital contributions in high tech areas like space, high energy particle accelerators, large plasma systems, electronics, thin films, melting and refining of metals, extraction and processing of advanced materials etc. The main areas covered in the symposium were the production and measurement of vacuums, leak detection, large vacuum systems, vacuum metallurgy, vacuum materials and processing inclusive of applications of vacuum in industry. Large vacuum systems for high energy particle accelerators, plasma devices and light sources are of special significance for this symposium. Vacuum evaporation, hard coatings, thin films, joining techniques, sintering, melting and heat treatment, furnaces and thermo dynamics are also covered in this symposium. There were eighteen invited talks from the best experts in the respective fields and more than one hundred contributed papers. This fact itself indicates the interest that has been generated amongst the scientists, technologists and industrialists in this field. In view of the industrial significance of the vacuum technology, an exhibition of vacuum and vacuum processing related equipments, accessories, products etc by different manufacturers and suppliers has been organized at the venue of the symposium hall for the benefit of the participants. The interest shown by the exhibitors reveals that the industry has come of age and the advances that have taken place over the years is quite significant. During the symposium, the Indian Vacuum Society felicitated two distinguished personalities who have contributed significantly for the development of vacuum science and technology in the country. The C AMBASANKARAN memorial and Smt SHAKUNTALABAI VYAWAHARE memorial Awards were also conferred on the two best contributed papers. A committee constituted by the Symposium Organizing Committee evaluated the relevance, scientific content, and clarity of presentation to decide the award winning papers. It is hoped that the discussion generated by the delegates at the symposium will help in a better understanding vacuum science and technology. K C Mittal Convener S K Gupta Co Convener International Advisory Committee Kakodkar, Anil DAE/India, Chairman Badve, Cdr A.V.(IN Retd.) Pfeiffer Vac India Banerjee, S. BARC/India Bhandari, R.K. BRNS/India Chander, Shekhar CEERI/India Chopra, K.L. IIT Delhi/India Day, Chris ITER Grover, R.B DAE,BARC/India Jakub, Szajman VSA/ Australia Jayaraj, R.N. NFC/India Kamath, H.S. BARC/India Kaw, P.K. IPR/India Kobayashi, M. VSJ/Japan Kumar, Lalit MTRDC, India Kumar, Vikram NPL., India Langley, Robert AVS, USA Larour, Jean Ecole/France Mendonsa, R.H. Lawrence and Mayo Myneni, Ganapatirao Jlab/USA Narsaiah, S.V. HHV Padamsee, Hasan Cornell/USA Pillay, R.G. TIFR Raj, Baldev IGCAR/India Raju, P.T. IVS/India Ramasami, T. DST/India Ray, A.K. BARC/India Reid, RJ IUVSTA/UK Roy, Amit IUAC/india Sahni, V.C. RRCAT, BARC/India Schamiloglu, E. UNM/USA Shankara, K.N. VSSC,ISRO/India Sinha, Bikash VEC,SINP/India Strubin, P. CERN/Switzerland Local Organizing Committee Ray, A.K. BARC (Chairman) Kailas, S. BARC, (Co Chairman) Chakravarty, D.P. BARC Chandrachoodan, P.P. BRNS Desai, Tushar Mumbai Univ. Dhamija, Lokesh BOC Edwards Dixit, Anand New Poona Ind. Gadkari, S.C. BARC Gantayet, L.M BARC Gupta, A.C. NPL Gupta, S.K. BARC (Co Convener) Handu, V.K. BARC Jathar, Rajendra Varian Joshi, S.N. CEERI Korgaonkar, A.V. IVS Kotaiah, S. CAT Kumar, Vijay BARC Matkar, A.W. BARC Mittal, K.C. BARC (Convener) Nema, P.K. BRNS Pandit, V.S. VEC Puranik, S.G. Ashwani Enterprises Puri, R.R. BARC Ranga Rao, Y. Vac. Techniques Sabharwal, Rajat Alcatel Sakhamuri, Prashant HHV Bangalore Sanyal, T. NFC Sarkar, S.K. TIFR Sarma, K.R. Atomic Vacuum Saxena, Y.C. IPR Sharma, B.P. BARC Shukla, S.K. RRCAT Singh, R.P. BARC Suri, A.K. BARC Suthar ,R.L. BARC Venugopa,l V. BARC Vyavahare, Mohan Ultimate Technologies Yakhmi, J.V. BARC

Breakdown-Resistant RF Connectors for Vacuum

NASA Technical Reports Server (NTRS)

Caro, Edward R.; Bonazza, Walter J.

1987-01-01

Resilient inserts compensate for insulation shrinkage. Coaxial-cable connector for radio-frequency (RF) energy resists electrical breakdown in vacuum. Used on RF equipment in vacuum chambers as well as in spaceborne radar and communication gear.

Safety shield for vacuum/pressure-chamber windows

NASA Technical Reports Server (NTRS)

Shimansky, R. A.; Spencer, R.

1980-01-01

Optically-clear shatter-resistant safety shield protects workers from implosion and explosion of vacuum and pressure windows. Plastic shield is inexpensive and may be added to vacuum chambers, pressure chambers, and gas-filling systems.

Vacuum system transient simulator and its application to TFTR

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

Sredniawski, J.

The vacuum system transient simulator (VSTS) models transient gas transport throughout complex networks of ducts, valves, traps, vacuum pumps, and other related vacuum system components. VSTS is capable of treating gas models of up to 10 species, for all flow regimes from pure molecular to continuum. Viscous interactions between species are considered as well as non-uniform temperature of a system. Although this program was specifically developed for use on the Tokamak Fusion Test Reactor (TFTR) project at Princeton, it is a generalized tool capable of handling a broad range of vacuum system problems. During the TFTR engineering design phase, VSTSmore » has been used in many applications. Two applications selected for presentation are: torus vacuum pumping system performance between 400 Ci tritium pulses and tritium backstreaming to neutral beams during pulses.« less

Color stability of ground beef packaged in a low carbon monoxide atmosphere or vacuum.

PubMed

Jeong, Jong Youn; Claus, James R

2011-01-01

Ground beef was either packaged in an atmosphere of 0.4% CO, 30% CO₂, and 69.6% N₂ (CO-MAP) or vacuum. After storage (48 h, 2-3°C), packages of CO-MAP and vacuum were opened and overwrapped with polyvinyl chloride. Other CO-MAP and vacuum packages were left intact. Packages were initially displayed for 7 days (2-3°C). Intact packages were further displayed up to 35 days before being opened and displayed (1 or 3 days). Intact CO-MAP packaged ground beef was always more red than intact vacuum-packaged ground beef. Color was relatively stable for both types of intact packages over 35 days of display. Upon opening CO-MAP packaged ground beef, the red color decreased slower than in ground beef from vacuum packages. Published by Elsevier Ltd.

Vacuum deposition and curing of liquid monomers apparatus

DOEpatents

Affinito, J.D.

1996-08-20

The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface. 3 figs.

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

DTIC Science & Technology

2014-10-01

Award Number: W81XWH-10-1-0744 TITLE: Development of Subischial Prosthetic Sockets with Vacuum...REPORT TYPE Annual 3. DATES COVERED 15 Sep 2013 – 14 Sep 2014 4. TITLE AND SUBTITLE Development of Subischial Prosthetic Sockets with Vacuum...to develop a highly flexible sub-ischial prosthetic socket with assisted-vacuum suspension for highly active persons with transfemoral amputation. The

Advanced Photon Source accelerator ultrahigh vacuum guide

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

Liu, C.; Noonan, J.

1994-03-01

In this document the authors summarize the following: (1) an overview of basic concepts of ultrahigh vacuum needed for the APS project, (2) a description of vacuum design and calculations for major parts of APS, including linac, linac waveguide, low energy undulator test line, positron accumulator ring (PAR), booster synchrotron ring, storage ring, and insertion devices, and (3) cleaning procedures of ultrahigh vacuum (UHV) components presently used at APS.

Radio frequency coaxial feedthrough device

DOEpatents

Owens, Thomas L.; Baity, Frederick W.; Hoffman, Daniel J.; Whealton, John H.

1987-01-01

A radio frequency coaxial vacuum feedthrough is provided which utilizes a cylindrical ceramic vacuum break formed of an alumina ceramic. The cylinder is coaxially disposed and brazed between tapered coaxial conductors to form a vacuum sealed connection between a pressurized upstream coaxial transmission line and a utilization device located within a vacuum container. The feedthrough provides 50 ohm matched impedance RF feedthrough up to about 500 MHz at power levels in the multimegawatt range.

Preparation, Delivery, and Evaluation of Picomole Vapor Standards

DTIC Science & Technology

2013-07-10

brass bellows vacuum valve (Part No. BFLM-K40, Duniway Stockroom Corp., Mountain View, CA USA). A scroll pump was used rather than a mechanical...evacuated 1 L ballast canister, while the dead volume of the quick connect is evacuated with a turbomolecular vacuum pump . 3 Figure 1: Valve layout...mL canister for 2 min. GC Splitless Inlet GC Splitless Inlet Turbomolecular Vacuum Pump Turbomolecular Vacuum Pump QT Quick

Steam-jet Chiller for Army Field Kitchens

DTIC Science & Technology

2009-08-01

Steam-Jet Test-Loop Schematic A vacuum pump removes air from the entire system on startup, and is occasionally used to expel air during...delivered to the tube and shell condenser. The steam is condensed and drains to the vacuum sump tank. 11 Periodically, the condensate pump ... Vacuum Roughing Pump The condenser must be held at vacuum to prevent air from insulating the condenser tubes or create a back-pressure that would

Flow chamber

DOEpatents

Morozov, Victor [Manassas, VA

2011-01-18

A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.

In-Vacuum Dissociator for Atomic-Hydrogen Masers

NASA Technical Reports Server (NTRS)

Vessot, R. F.

1987-01-01

Thermal control and vacuum sealing achieved while contamination avoided. Simple, relatively inexpensive molecular-hydrogen dissociator for atomic-hydrogen masers used on Earth or in vacuum of space. No air cooling required, and absence of elastomeric O-ring seals prevents contamination. In-vacuum dissociator for atomic hydrogen masers, hydrogen gas in glass dissociator dissociated by radio-frequency signal transmitted from surrounding 3-turn coil. Heat in glass conducted away by contacting metal surfaces.

Effect of vacuum and of strong adsorbed water films on micropore formation in aluminum hydroxide xerogel powders.

PubMed

Beruto, Dario T; Botter, Rodolfo; Converti, Attilio

2009-02-01

Aluminum hydroxide gels were washed with water, ethanol, methanol and isopropanol to obtain new gels with different liquid phases that were dried either in air at 120 degrees C or under vacuum at 80 degrees C. Drying in air leads to alcoholic xerogels with BET surface areas larger than the aqueous ones. The effect of the alcoholic groups as substitutes of the hydroxyl ones has been discussed to account for the final size of xerogel crystallites. Drying under vacuum decreases the BET surface of the methanol xerogels, but no micropores are formed in all the alcoholic xerogel matrixes. On the contrary, the vacuum drying process changes significantly the microstructure of the aqueous xerogels. Their BET surface increases by 34 m(2)/g, and micropores are formed within their crystallite aggregates. It has been experimentally shown that these changes are due to a shear transformation that occurs in the boehmite xerogels obtained under vacuum. To discuss these data, the existence of chemical compounds such as AlOOHnH(2)O was postulated. On this ground, a neat analogy between vacuum drying process and vacuum interfacial decomposition reactions of inorganic salts can be drawn. This analogy explains how a state of stresses forms in aqueous xerogel matrix during vacuum drying process.

Load responsive multilayer insulation performance testing

NASA Astrophysics Data System (ADS)

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

2014-01-01

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

Development of a Control System for the Teat-End Vacuum in Individual Quarter Milking Systems

PubMed Central

Ströbel, Ulrich; Rose-Meierhöfer, Sandra; Öz, Hülya; Brunsch, Reiner

2013-01-01

Progress in sensor technique and electronics has led to a decrease in the costs of electronic and sensor components. In modern dairy farms, having udders in good condition, a lower frequency of udder disease and an extended service life of dairy cows will help ensure competitiveness. The objective of this study was to develop a teat-end vacuum control system with individual quarter actor reaction. Based on a review of the literature, this system is assumed to protect the teat tissue. It reduces the mean teat-end vacuum in the maximum vacuum phase (b) to a level of 20 kPa at a flow rate of 0.25 L/min per quarter. At flow rates higher than 1.50 L/min per quarter, the teat-end vacuum can be controlled to a level of 30 kPa, because in this case it is desirable to have a higher vacuum for the transportation of the milk to the receiver. With this system it is possible for the first time to supply the teat end with low vacuum at low flow rates and with higher vacuum at increasing flow rates in a continuous process with a three second reaction-rate on individual quarter level. This system is completely automated. PMID:23765272

Research on influence of different cover to the characteristic of FBG reflectance spectrum in vacuum thermal environment

NASA Astrophysics Data System (ADS)

Pei, Yifei; Zhang, Jingchuan; Zhang, Luosha; Liu, Yang; Zhang, Lina; Chen, Shiyu

2018-01-01

To satisfy the application of fiber grating sensor technology in high vacuum thermal environment, two different kinds of sleeve compactly single model fiber covered by acrylate and polyimide are researched. Influence of the cover to the characteristic of FBG reflectance spectrum in high vacuum thermal environment is analyzed and verified. First, transmission characteristic of single model fiber in high vacuum thermal environment is analyzed by solve the equation of heat conduction. Then, experimental program of influence on FBG reflection spectrum characteristics is designed and a hardware-in-the-loop detection platform is set up. Finally, the influence of temperature and vacuum on the reflection peak power of FBG in different coating single-mode transmission fiber under high vacuum thermal environment is studied and verified. Experimental results indicate that: when vacuum varied from normal pressure to 10-4Pa level and then return to normal pressure, temperature of two different coating single-mode transmission fiber dropped to -196 ° from room temperature and then returned to room temperature, after 224 hours, the peak power of the FBG reflectance spectrum did not change. It provided the theoretical and experimental basis for the application of optical fiber sensing technology in high vacuum (pressure about 10-4Pa level) and thermal environment (-196 ° 25 ° temperature cycle) .

Red rubber bulb, cheap and effective vacuum drainage.

PubMed

Vatanasapt, V; Areemit, S; Jeeravipoolvarn, P; Kuyyakanond, T; Kuptarnond, C

1989-04-01

Red rubber bulbs have been used for vacuum drainage in head, neck, breast and several other operations by the authors since 1975 quite effectively without any major problems. The vacuum pressure of the red rubber bulbs was found to be higher than the expensive commercially available vacuum wound drainage device. The question of remaining old blood and infective microorganisms inside the reservoir for the reused ones were tested by the manual cleaning process and the standard sterile technique using steam under increased pressure (autoclave). The result is quite satisfactory. We encourage the use of this cheap and effective (made in Thailand) vacuum wound drainage in Thai hospitals and Thai medical schools.

NSLS II Vacuum System

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

Ferreira, M.; Doom, L.; Hseuh, H.

2009-09-13

National Synchrotron Light Source II, being constructed at Brookhaven, is a 3-GeV, 500 mA, 3rd generation synchrotron radiation facility with ultra low emittance electron beams. The storage ring vacuum system has a circumference of 792 m and consists of over 250 vacuum chambers with a simulated average operating pressure of less than 1 x 10{sup -9} mbar. A summary of the update design of the vacuum system including girder supports of the chambers, gauges, vacuum pumps, bellows, beam position monitors and simulation of the average pressure will be shown. A brief description of the techniques and procedures for cleaning andmore » mounting the chambers are given.« less

Study of Vacuum Energy Physics for Breakthrough Propulsion

NASA Technical Reports Server (NTRS)

Millis, Marc G. (Technical Monitor); Maclay, G. Jordan; Hammer, Jay; Clark, Rod; George, Michael; Kim, Yeong; Kir, Asit

2004-01-01

This report summarizes the accomplishments during a three year research project to investigate the use of surfaces, particularly in microelectromechanical systems (MEMS), to exploit quantum vacuum forces. During this project, we developed AFM instrumentation to repeatably measure Casimir forces in the nanoNewton range at 10 6 torr, designed an experiment to measure attractive and repulsive quantum vacuum forces, developed a QED based theory of Casimir forces that includes non-ideal material properties for rectangular cavities and for multilayer slabs, developed theoretical models for a variety of microdevices utilizing vacuum forces, applied vacuum physics to a gedanken spacecraft, and investigated a new material with a negative index of refraction.

Use of space ultra-vacuum for high quality semiconductor thin film growth

NASA Technical Reports Server (NTRS)

Ignatiev, A.; Sterling, M.; Sega, R. M.

1992-01-01

The utilization of space for materials processing is being expanded through a unique concept of epitaxial thin film growth in the ultra-vacuum of low earth orbit (LEO). This condition can be created in the wake of an orbiting space vehicle; and assuming that the vehicle itself does not pertub the environment, vacuum levels of better than 10 exp -14 torr can be attained. This vacuum environment has the capacity of greatly enhancing epitaxial thin film growth and will be the focus of experiments conducted aboard the Wake Shield Facility (WSF) currently being developed by the Space Vacuum Epitaxy Center (SVEC), Industry, and NASA.

Torsion pendulum measurements on viscoelastic materials during vacuum exposure

NASA Technical Reports Server (NTRS)

Ward, T. C.; Evans, M. L.

1972-01-01

A torsional pendulum apparatus designed for testing in situ in vacuum, the dynamic mechanical properties of materials is described. The application of this apparatus to an experimental program to measure the effects of vacuum on the mechanical properties of two ablator materials (a foamed material and a filled elastomer) and a solid rocket propellant (a filled elastomer) is presented. Results from the program are discussed as to the effects of vacuum on the mechanical properties of these three materials. In addition, time-temperature-superposition, as a technique for accelerating vacuum induced changes in mechanical properties, is discussed with reference to the three materials tested in the subject program.

Approximating Fluid Flow from Ambient to Very Low Pressures: Modeling ISS Experiments that Vent to Vacuum

NASA Technical Reports Server (NTRS)

Minor, Robert

2002-01-01

Two ISS (International Space Station) experiment payloads will vent a volume of gas overboard via either the ISS Vacuum Exhaust System or the Vacuum Resource System. A system of ducts, valves and sensors, under design, will connect the experiments to the ISS systems. The following tasks are required: Create an analysis tool that will verify the rack vacuum system design with respect to design requirements, more specifically approximate pressure at given locations within the vacuum systems; Determine the vent duration required to achieve desired pressure within the experiment modules; Update the analysis as systems and operations definitions mature.

Method for producing titanium aluminide weld rod

DOEpatents

Hansen, Jeffrey S.; Turner, Paul C.; Argetsinger, Edward R.

1995-01-01

A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.

Analysis of RFQ vacuum system for HINS tests at MDB

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

Piekarz, Henryk; /Fermilab

The arrangement of RFQ vacuum system is briefly described. The projections of the vacuum level using standard out-gassing rates for the RFQ major components are compared with measurements. The permeation of water through the Viton O-rings of the LCW manifold inside the RFQ vacuum vessel is analyzed and compared with RGA data. A model where the out-gassing water from the vanes inner surfaces affects seriously RFQ operation is devised and compared with RFQ performance. The rate of a hydrogen gas spill from the LEBT into the RFQ vacuum space is also projected. Suggestions to correct and improve RFQ operation aremore » presented.« less

[Evaluation of the quality of poultry meat and its processing for vacuum packaging].

PubMed

Swiderski, F; Russel, S; Waszkiewicz-Robak, B; Cholewińska, E

1997-01-01

The aim of study was to evaluate the quality of poultry meat, roasted and smoked chicken and poultry pie packing under low and high vacuum. All investigated products were stored at +4 degrees C and evaluated by microbiological analysis. It was showed that packing under low and high vacuum inhibited development of aerobic microorganisms, proteolytic bacteria, yeasts and moulds. Vacuum-packaged storage of poultry meat and its products stimulated activity of anaerobic, nonsporeforming bacteria. The fast spoilage of fresh poultry meat was observed both under vacuum and conventional storage. The microbiology quality of poultry products depended on technology of production and microbiological quality of raw material.

Potential and field produced by a uniform or non-uniform elliptical beam inside a confocal elliptic vacuum chamber

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

Regenstreif, E.

The potential produced by an isolated beam of elliptic cross-section seems to have been considered first by L.C. Teng. Image effects of line charges in elliptic vacuum chambers were introduced into accelerator theory by L. J. Laslett. Various approximate solutions for elliptic beams of finite cross-section coasting inside an elliptic vacuum chamber were subsequently proposed by P. Lapostolle and C. Bovet. A rigorous expression is derived for the potential produced by an elliptic beam inside an elliptic vacuum chamber, provided the beam envelope and the vacuum chamber can be assimilated to confocal ellipses.

Vacuum Chamber Documentation for U of H Collection

NASA Image and Video Library

2006-06-16

Documentation for the University of Houston (UH) Clear Lake collection of their library books after the Vacuum Chamber runs were performed to remove the water from them. Vacuum Chamber B in Building 32 was used.

Indian Vacuum Society: The Indian Vacuum Society

NASA Astrophysics Data System (ADS)

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 expert members on the subject to deliver lectures and take part in devising courses in the universities. IVS publishes a quarterly called the `Bulletin of Indian Vacuum Society' since its inception, in which articles on vacuum and related topics are published. NIRVAT, news, announcements, and reports are the other features of the Bulletin. The articles in the Bulletin are internationally abstracted. The Bulletin is distributed free to all the members of the society. The society also publishes proceedings of national/international symposia and seminars, manuals, lecture notes etc. It has published a `Vacuum Directory' containing very useful information on vacuum technology. IVS has also set up its own website http://www.ivsnet.org in January 2002. The website contains information about IVS, list of members, list of EC members, events and news, abstracts of articles published in the `Bulletin of Indian Vacuum Society', utilities, announcements, reports, membership and other forms which can be completed online and also gives links to other vacuum societies. Our Society has been a member of the executive council of the International Union of Vacuum Science, Techniques and Applications (IUVSTA) and its various committees since 1970. In 1983 IVS conducted an International Symposium on Vacuum Technology and Nuclear Applications in BARC, Mumbai, under the sponsorship of IUVSTA. In 1987 IVS arranged the Triennial International Conference on Thin Films in New Delhi, where more than 200 foreign delegates participated. IVS also hosted the IUVSTA Executive Council Meeting along with the conference. The society organized yet again an International Conference on Vacuum Science and Technology and SRS Vacuum Systems at CAT, Indore in1995. IVS arranges the prestigious Professor Balakrishnan Memorial Lecture in memory of its founder vice-president. Leading scientists from India and abroad in the field are invited to deliver the talks. So far 23 lectures have been held in this series. IVS has instituted the `IVS- Professor D Y Phadke Memorial Prize' in memory of our founder president, the late Professor D Y Phadke at the University of Mumbai. The prize is given every year to the student ranked top in the MSc (PHY.) examination conducted by the university. The IVS Kolkata Chapter has established the Dr A S Divatia Memorial Trust with the objective of organizing the Dr A S Divatia Memorial Lecture and a seminar once a year and to set up a vacuum testing and calibration facility. IVS has instituted an award in memory of the late Shri C Ambasankaran, its past president and pioneer of vacuum technology in India. This award is given to one of the best papers presented in the national symposium conducted by IVS. One more best paper award `Smt. Shakuntalabai Vyawahare Memorial Prize' is established from a donation given by Shri Mohan R Vyawahare, a life member and a present EC member of the society, in memory of his mother. During the symposia, IVS felicitates two of its members, one from Industry and one from an R & D Institution for their lifetime contribution to vacuum science and technology. Dr A K Gupta, Ex BARC, Ex Generla Manager, IBP, Head, Energy Group, Shapoorji Pallonji & Co Ltd (Industry), and Dr S R Gowariker, Ex BARC, Ex Director, CSIO, Chandigarh, Director, Tolani Education Foundation (R & D) are being honoured this year. T K Saha Geneneral Secretary, IVS

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

PubMed

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.

Three stage vacuum system for ultralow temperature installation

NASA Astrophysics Data System (ADS)

Das, N. K.; Pradhan, J.; Naser, Md Z. A.; Mandal, B. Ch; Roy, A.; Kumar, P.; Mallik, C.; Bhandari, R. K.

2012-11-01

We use a three stage vacuum system for developing a dilution fridge at VECC, Kolkata. We aim at achieving a cooling power of 20μW at 100mK for various experiments especially in the field of condensed matter and nuclear physics. The system is essentially composed of four segments-bath cryostat, vacuum system, dilution insert and 3He circulation circuit. Requirement of vacuum system at different stages are different. The vacuum system for cryostat and for internal vacuum chamber located within the helium bath is a common turbo molecular pump backed by scroll pump as to maintain a vacuum ~10-6mbar. For bringing down the temperature of the helium evaporator, we use a high throughput Roots pump backed by a dry pump. The pumping system for 3He distillation chamber (still) requires a high pumping speed, so a turbo drag pump backed by a scroll pump has been installed. As the fridge use precious 3He gas for operation, the entire system has been made to be absolutely leak proof with respect to the 3He gas.

A highly miniaturized vacuum package for a trapped ion atomic clock

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

Schwindt, Peter D. D., E-mail: pschwin@sandia.gov; Jau, Yuan-Yu; Partner, Heather

2016-05-15

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

Apple snack enriched with L-arginine using vacuum impregnation/ohmic heating technology.

PubMed

Moreno, Jorge; Echeverria, Julian; Silva, Andrea; Escudero, Andrea; Petzold, Guillermo; Mella, Karla; Escudero, Carlos

2017-07-01

Modern life has created a high demand for functional food, and in this context, emerging technologies such as vacuum impregnation and ohmic heating have been applied to generate functional foods. The aim of this research was to enrich the content of the semi-essential amino acid L-arginine in apple cubes using vacuum impregnation, conventional heating, and ohmic heating. Additionally, combined vacuum impregnation/conventional heating and vacuum impregnation/ohmic heating treatments were evaluated. The above treatments were applied at 30, 40 and 50  ℃ and combined with air-drying at 40 ℃ in order to obtain an apple snack rich in L-arginine. Both the impregnation kinetics of L-arginine and sample color were evaluated. The impregnated samples created using vacuum impregnation/ohmic heating at 50 ℃ presented a high content of L-arginine, an effect attributed primarily to electropermeabilization. Overall, vacuum impregnation/ohmic heating treatment at 50 ℃, followed by drying at 40 ℃, was the best process for obtaining an apple snack rich in L-arginine.

Instrument for measurement of vacuum in sealed thin wall packets

DOEpatents

Kollie, T.G.; Thacker, L.H.; Fine, H.A.

1993-10-05

An instrument is described for the measurement of vacuum within sealed packets, the packets having a wall sufficiently thin that it can be deformed by the application of an external vacuum to small area thereof. The instrument has a detector head for placement against the deformable wall of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall, with this deformation or lift monitored by the application of light as via a bifurcated light pipe. Retro-reflected light through the light pipe is monitored with a photo detector. An abrupt change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the vacuum applied through the head to achieve this initiation of movement is equal to the vacuum within the packet. In a preferred embodiment a vacuum reference plate is placed beneath the packet to ensure that no deformation occurs on the reverse surface of the packet. A packet production line model is also described. 3 figures.

Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System

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

Stutzman, M L; Adderley, P; Brittian, J

A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower partmore » of the UHV range. Measured NEG pump speed is high at pressures above 5×10 -11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.« less

Technical specification for vacuum systems

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

Khaw, J.

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 andmore » 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)« less

A novel post-arc current measuring equipment based on vacuum arc commutation and arc blow

NASA Astrophysics Data System (ADS)

Liao, Minfu; Ge, Guowei; Duan, Xiongying; Huang, Zhihui

2017-07-01

The paper proposes a novel post-arc current measuring equipment (NPACME), which is based on the vacuum arc commutation and magnetic arc blow. The NPACME is composed of the vacuum circuit breaker (VCB), shunt resistor, protective gap, high-precision current sensor and externally applied transverse magnetic field (ETMF). The prototype of the NPACME is designed and controlled by optical fiber communications. The vacuum arc commutation between the vacuum arc and the shunt resistor with ETMF is investigated. The test platform is established in the synthetic short-circuit test and the vacuum arc is observed by the high speed CMOS camera. The mathematic description of the vacuum arc commutation is obtained. Based on the current commutation characteristic, the parameters of the NPACME are optimized and the post-arc current is measured. The measuring result of the post-arc current is accurate with small interference and the post-arc charge is obtained. The experimental results verify that the NPACME is correct and accurate, which can be used to measure the post-arc characteristic in breaking test.

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

PubMed

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.

Instrument for measurement of vacuum in sealed thin wall packets

DOEpatents

Kollie, Thomas G.; Thacker, Louis H.; Fine, H. Alan

1993-01-01

An instrument for the measurement of vacuum within sealed packets 12, the packets 12 having a wall 14 sufficiently thin that it can be deformed by the application of an external vacuum to small area thereof. The instrument has a detector head 18 for placement against the deformable wall 14 of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall 14, with this deformation or lift monitored by the application of light as via a bifurcated light pipe 20. Retro-reflected light through the light pipe is monitored with a photo detector 26. An abrupt change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the vacuum applied through the head 18 to achieve this initiation of movement is equal to the vacuum Within the packet 12. In a preferred embodiment a vacuum reference plate 44 is placed beneath the packet 12 to ensure that no deformation occurs on the reverse surface 16 of the packet. A packet production line model is also described.

Nonperturbative vacuum polarization effects in two-dimensional supercritical Dirac-Coulomb system I. Vacuum charge density

NASA Astrophysics Data System (ADS)

Davydov, A.; Sveshnikov, K.; Voronina, Yu.

2018-01-01

Based on the original combination of analytical methods, computer algebra tools and numerical calculations, proposed recently in Refs. 1-3, the nonperturbative vacuum polarization effects in the 2+1D supercritical Dirac-Coulomb system with Z > Zcr,1 are explored. Both the vacuum charge density ρV P(r→) and vacuum energy ℰV P are considered. The main result of the work is that in the overcritical region ℰV P turns out to be a rapidly decreasing function ˜-ηeffZ3/R with ηeff > 0 and R being the size of the external Coulomb source. Due to a lot of details of calculation the whole work is divided into two parts I and II. In the present part I, we consider the evaluation and behavior of the vacuum density ρV P, which further is used in part II for evaluation of the vacuum energy, with emphasis on the renormalization, convergence of the partial expansion for ρV P and behavior of the integral induced charge QV P in the overcritical region.

500(deg)C electronics for harsh environments

NASA Technical Reports Server (NTRS)

Sadwick, Laurence P.; Hwu, R. Jennifer; Chern, J. H. Howard; Lin, Ching-Hsu; Castillo, Linda Del; Johnson, Travis

2005-01-01

Solid state vacuum devices (SSVDs) are a relatively new class of electronic devices. Innosys is a leading producer of high frequency SSVDs for a number of applications, including RF communications. SSVDs combine features inherent to both solid state and vacuum transistors. Electron transport can be by solid state or vacuum or both. The focus of this talk is on thermionic SSVDs, in which the primary vacuum transport is by thermionically liberated electron emission.

Basic Research on Plasma Cathode for HPM Sources (NE - Luginsland)

DTIC Science & Technology

2011-11-30

to NEPP Vacuum Pump for Mock Magnetron 12 (b) Borosilicate glass (Insulator)  Anode Cathode Vacuum chamber Ion gauge controller Charge...channeling may be one physical mechanism that can explain the stability of the pinch in the discharge. (a) Scroll Pump High Voltage Power Supply DC... vacuum and/or low vacuum slow wave devices and cross field devices) in burst mode? Here, burst mode effectively implies an impulse-like (short pulse

A 2.5 Gigawatt Liquid Dielectric Coaxial Pulse Forming Line

DTIC Science & Technology

1987-06-01

operation. The fuses provide protection against long term faults. The 3 phase vacuum contactor is a convenient means of remotely applying or...is electronically sensed and the vacuum contactor opens thereby interrupting the input power. The opening time of the vacuum contactor is less than...less than 5 microseconds and at the same time a trigger signal is sent to the vacuum contactor which opens and interrupts the primary power. The PFL

40 CFR Table 31 to Subpart G of... - Typical Number of Vacuum Breakers, NF6 and Roof Drains, a NF7

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Typical Number of Vacuum Breakers, NF6..., and Wastewater Pt. 63, Subpt. G, Table 31 Table 31 to Subpart G of Part 63—Typical Number of Vacuum Breakers, NF6 and Roof Drains, a NF7 Tank diameter D (feet) b No. of vacuum breakers, NF6 Pontoon roof...

Latest Trends of Vacuum Circuit Breaker and Related Technologies

NASA Astrophysics Data System (ADS)

Kozono, Hideaki; Tanimizu, Toru

Vacuum Circuit Breakers (VCBs) have been widely used for medium voltage level, because of their performance: compact size, light weight, maintenance free operations and environment-friendly characteristics. They become most comfortable breakers for our needs from other breakers: oil, air, magnetic blast and gas. In this paper the history of vacuum, and latest trends of circuit breakers and related technologies are described, as well as merits or demerits of using vacuum technologies.

Investigation of Re-X glass ceramic for acceleration insulating columns

NASA Astrophysics Data System (ADS)

Faltens, A.; Rosenblum, S.

1985-05-01

In an induction linac the accelerating voltage appears along a voltage-graded vacuum insulator column which is a performance limiting and major cost component. Re-X glass ceramic insulators have the long-sought properties of allowing cast-in gradient electrodes, good breakdown characteristics, and compatibility with high vacuum systems. Re-X is a glass ceramic developed by General Electric for use in the manufacture of electrical apparatus, such as vacuum arc interrupters. We have examined vacuum outgassing behavior and voltage breakdown in vacuum and find excellent performance. The housings are in the shape of tubes with type 430 stainless steel terminations. Due to a matched coefficient of thermal expansion between metal and insulator, no vacuum leaks have resulted from any welding operation. The components should be relatively inexpensive to manufacture in large sizes and appear to be a very attractive accelerator column. We are planning to use a standard GE housing in our MBE-4 induction linac.

Quantum vacuum effects from boundaries of designer potentials

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

Konopka, Tomasz

2009-04-15

Vacuum energy in quantum field theory, being the sum of zero-point energies of all field modes, is formally infinite but yet, after regularization or renormalization, can give rise to finite observable effects. One way of understanding how these effects arise is to compute the vacuum energy in an idealized system such as a large cavity divided into disjoint regions by pistons. In this paper, this type of calculation is carried out for situations where the potential affecting a field is not the same in all regions of the cavity. It is shown that the observable parts of the vacuum energymore » in such potentials do not fall off to zero as the region where the potential is nontrivial becomes large. This unusual behavior might be interesting for tests involving quantum vacuum effects and for studies on the relation between vacuum energy in quantum field theory and geometry.« less

A squeezed light source operated under high vacuum

PubMed Central

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

2015-01-01

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. PMID:26657616

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

Furuya, K.; Yago, T.

A system is disclosed for rapidly warming up a catalytic converter provided to an automotive internal combustion engine to purify the exhaust gas. The system includes a vacuum-operated device to increase the opening degree of the throttle valve by a predetermined degree to thereby increase the quantity of the exhaust gas and another vacuum-operated device to retard the ignition timing of the engine to a predetermined extent to thereby raise the temperature of the exhaust gas. The two devices are connected by a vacuum passage to the intake passage of the engine at a section downstream of the throttle valvemore » in series, and an electromagnetic valve renders the vacuum passage effective to thereby actuate the vacuum-operated devices only when the engine is idling under cold condition. Because of the series connection of the two devices, an intake vacuum is applied to the two devices in desirable sequence.« less

Development of a large low-cost double-chamber vacuum laminator

NASA Technical Reports Server (NTRS)

Burger, D. R.

1983-01-01

A double-chamber vacuum laminator was required to investigate the processing and control of the fabrication of large terrestrial photovoltaic modules, and economic problems arising therefrom. Major design considerations were low cost, process flexibility and the exploration of novel equipment approaches. Spherical end caps for industrial tanks were used for the vacuum chambers. A stepping programmer and adjustable timers were used for process flexibility. New processing options were obtained by use of vacuum sensors. The upper vacuum chamber was provided with a diaphragm support to reduce diaphragm stress. A counterweight was used for handling ease and safety. Heat was supplied by a large electrical strip heater. Thermal isolation and mechanical support were provided inexpensively by a bed of industrial marbles. Operational testing disclosed the need for a differential vacuum gauge and proportional valve. Reprogramming of the process control system was simple and quick.

Upgrade of The Thermal Vacuum Data System at NASA/GSFC

NASA Technical Reports Server (NTRS)

Palmer, John; Powers, Edward I. (Technical Monitor)

2000-01-01

The Goddard Space Flight Center's new thermal vacuum data acquisition system is a networked client-sever application that enables lab operations crews to monitor all tests from a central location. The GSFC thermal vacuum lab consists of eleven chambers in Building 7 and one chamber in Building 10. The new data system was implemented for several reasons. These included the need for centralized data collection, more flexible and easier to use operator interface, greater data accessibility, a reduction in testing time and cost, and increased payload and personnel safety. Additionally, a new data system was needed for year-2000 compliance. This paper discusses the incorporation of the Thermal Vacuum Data System (TVDS) within the thermal vacuum lab at GSFC, its features and capabilities and lessons learned in its implementation. Additional topics include off-center (Internet) capability for remote monitoring and the role of TVDS in the efforts to automate thermal vacuum chamber operations.

Flow Visualization Proposed for Vacuum Cleaner Nozzle Designs

NASA Technical Reports Server (NTRS)

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

A squeezed light source operated under high vacuum

NASA Astrophysics Data System (ADS)

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

2015-12-01

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.

Upgrade of the Thermal Vacuum Data System at NASA/GSFC

NASA Technical Reports Server (NTRS)

Palmer, John

2000-01-01

The Goddard Space Flight Center's new thermal vacuum data acquisition system is a networked client-sever application that enables lab operations crews to monitor all tests from a central location. The GSFC thermal vacuum lab consists of eleven chambers in Building 7 and one chamber in Building 10. The new data system was implemented for several reasons. These included the need for centralized data collection, more flexible and easier to use operator interface, greater data accessibility, a reduction in testing time and cost, and increased payload and personnel safety. Additionally, a new data system was needed for year-2000 compliance. This paper discusses the incorporation of the Thermal Vacuum Data System (TVDS) within the thermal vacuum lab at GSFC, its features and capabilities and lessons learned in its implementation. Additional topics include off-center (Internet) capability for remote monitoring and the role of TVDS in the efforts to automate thermal vacuum chamber operations.

Simulation of the synergistic low Earth orbit effects of vacuum thermal cycling, vacuum UV radiation, and atomic oxygen

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Degroh, Kim K.; Stidham, Curtis R.; Stueber, Thomas J.; Dever, Therese M.; Rodriguez, Elvin; Terlep, Judith A.

1992-01-01

In order to assess the low Earth orbit (LEO) durability of candidate space materials, it is necessary to use ground laboratory facilities which provide LEO environmental effects. A facility combining vacuum thermal cycling and vacuum ultraviolet (VUV) radiation has been designed and constructed at NASA Lewis Research Center for this purpose. This facility can also be operated without the VUV lamps. An additional facility can be used to provide VUV exposure only. By utilizing these facilities, followed by atomic oxygen exposure in an RF plasma asher, the effects of the individual vacuum thermal cycling and VUV environments can be compared to the effect of the combined vacuum thermal cycling/VUV environment on the atomic oxygen durability of materials. The synergistic effects of simulated LEO environmental conditions on materials were evaluated by first exposing materials to vacuum thermal cycling, VUV, and vacuum thermal cycling/VUV environments followed by exposure to atomic oxygen in an RP plasma asher. Candidate space power materials such as atomic oxygen protected polyimides and solar concentrator mirrors were evaluated using these facilities. Characteristics of the Vacuum Thermal Cycling/VUV Exposure Facility which simulates the temperature sequences and solar ultraviolet radiation exposure that would be experienced by a spacecraft surface in LEO are discussed. Results of durability evaluations of some candidate space power materials to the simulated LEO environmental conditions will also be discussed. Such results have indicated that for some materials, atomic oxygen durability is affected by previous exposure to thermal cycling and/or VUV exposure.

Management of hidradenitis suppurativa wounds with an internal vacuum-assisted closure device.

PubMed

Chen, Y Erin; Gerstle, Theodore; Verma, Kapil; Treiser, Matthew D; Kimball, Alexandra B; Orgill, Dennis P

2014-03-01

Hidradenitis suppurativa is a chronic, debilitating disease that is difficult to treat. Once medical management fails, wide local excision offers the best chance for cure. However, the resultant wound often proves too large or contaminated for immediate closure. The authors performed a retrospective chart review of hidradenitis cases managed surgically between 2005 and 2010. Data collected included patient characteristics, management method, and outcomes. Approximately half of the patients received internal vacuum-assisted closure therapy using the vacuum-assisted closure system and delayed closure and half of the patients received immediate primary closure at the time of their excision. Delayed closure consisted of closing the majority of the wound in a linear fashion following internal vacuum-assisted closure while accepting healing by means of secondary intention for small wound areas. Patients managed with internal vacuum-assisted closure had wounds on average four times larger in area than patients managed without internal vacuum-assisted closure. In both groups, all wounds were eventually closed primarily. Healing times averaged 2.2 months with internal vacuum-assisted closure and 2.7 months without. At an average follow-up time of 2.3 months, all patients with internal vacuum-assisted closure had no recurrence of their local disease. Severe hidradenitis presents a treatment challenge, as surgical excisions are often complicated by difficult closures and unsatisfactory recurrence rates. This study demonstrates that wide local excision with reasonable outcomes can be achieved using accelerated delayed primary closure. This method uses internal vacuum-assisted closure as a bridge between excision and delayed primary closure, facilitating closure without recurrence in large, heavily contaminated wounds. Therapeutic, III.

Viability of Cladosporium herbarum spores under 157 nm laser and vacuum ultraviolet irradiation, low temperature (10 K) and vacuum

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

Sarantopoulou, E., E-mail: esarant@eie.gr; Stefi, A.; Kollia, Z.

Ultraviolet photons can damage microorganisms, which rarely survive prolonged irradiation. In addition to the need for intact DNA, cell viability is directly linked to the functionality of the cell wall and membrane. In this work, Cladosporium herbarum spore monolayers exhibit high viability (7%) when exposed to 157 nm laser irradiation (412 kJm⁻²) or vacuum-ultraviolet irradiation (110–180 nm) under standard pressure and temperature in a nitrogen atmosphere. Spore viability can be determined by atomic-force microscopy, nano-indentation, mass, μ-Raman and attenuated reflectance Fourier-transform far-infrared spectroscopies and DNA electrophoresis. Vacuum ultraviolet photons cause molecular damage to the cell wall, but radiation resistance inmore » spores arises from the activation of a photon-triggered signaling reaction, expressed via the exudation of intracellular substances, which, in combination with the low penetration depth of vacuum-ultraviolet photons, shields DNA from radiation. Resistance to phototoxicity under standard conditions was assessed, as was resistance to additional environmental stresses, including exposure in a vacuum, under different rates of change of pressure during pumping time and low (10 K) temperatures. Vacuum conditions were far more destructive to spores than vacuum-ultraviolet irradiation, and UV-B photons were two orders of magnitude more damaging than vacuum-ultraviolet photons. The viability of irradiated spores was also enhanced at 10 K. This work, in addition to contributing to the photonic control of the viability of microorganisms exposed under extreme conditions, including decontamination of biological warfare agents, outlines the basis for identifying bio-signaling in vivo using physical methodologies.« less

Vacuum enhanced cutaneous biopsy instrument

DOEpatents

Collins, Joseph

2000-01-01

A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.

Analysis of influence of different pressure and different depth of pvd on soft foundation treatment

NASA Astrophysics Data System (ADS)

Li, Bin; Wang, XueKui

2018-02-01

According to the depth of plastic vertical drainage (pvd), the arrangement mode and the loading mode to analyze the influence of Vacuum preloading near the existing road. An arrangement mode of vacuum preloading to reduce the impact was put forward. The combination of different depth of pvd and loading modes are used to analyze the effect of vacuum preloading treatment and its influence range. The calculations show that the deformation and the influence distance are smaller by using the 40kPa vacuum loading and 41kPa surcharge load preloading. Reducing the depth of the pvd and vacuum combined surcharge preloading can weaken the influence to the existing highway.

Vacuum system design and tritium inventory for the TFTR charge exchange diagnostic

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

Medley, S.S.

The charge exchange diagnostic for the TFTR is comprised of two analyzer systems which contain a total of twenty independent mass/energy analyzers and one diagnostic neutral beam tentatively rated at 80 keV, 15 A. The associated vacuum systems were analyzed using the Vacuum System Transient Simulator (VSTS) computer program which models the transient transport of multi-gas species through complex networks of ducts, valves, traps, vacuum pumps, and other related vacuum system components. In addition to providing improved design performance at reduced cost, the analysis yields estimates for the exchange of tritium from the torus to the diagnostic components and ofmore » the diagnostic working gases to the torus.« less

Gravitational collapse and the vacuum energy

NASA Astrophysics Data System (ADS)

Campos, M.

2014-03-01

To explain the accelerated expansion of the universe, models with interacting dark components (dark energy and dark matter) have been considered recently in the literature. Generally, the dark energy component is physically interpreted as the vacuum energy of the all fields that fill the universe. As the other side of the same coin, the influence of the vacuum energy on the gravitational collapse is of great interest. We study such collapse adopting different parameterizations for the evolution of the vacuum energy. We discuss the homogeneous collapsing star fluid, that interacts with a vacuum energy component, using the stiff matter case as example. We conclude this work with a discussion of the Cahill-McVittie mass for the collapsed object.

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

Restivo, M.

SRNL Environmental and Chemical Process Technology (E&CPT) was requested to perform testing of vacuum pumps per a verbal request from the Customer, SRNL Hydrogen Processing Technology. Tritium Operations is currently having difficulties procuring the Normetex™® Model 15 m 3/hr (9 CFM) vacuum pump (formerly Normetex Pompes, now Eumeca SARL). One possible solution proposed by Hydrogen Processing Technology personnel is to use two Senior Aerospace Metal Bellows MB-601 vacuum pumps piped with the heads in series, and the pumps in series (Figure 1 below). This memorandum documents the ultimate vacuum testing that was performed to determine if this concept was amore » viable alternate vacuum pump strategy. This testing dovetails with previous pump evaluations documented in references 1 and 2.« less

Dynamics of the Vacuum and Casimir Analogs to the Hydrogen Atom

NASA Technical Reports Server (NTRS)

White, Harold; Vera, Jerry; Bailey, Paul; March, Paul; Lawrence, Tim; Sylvester, Andre; Brady, David

2015-01-01

This paper will discuss the current viewpoint of the vacuum state and explore the idea of a "natural" vacuum as opposed to immutable, non-degradable vacuum. This concept will be explored for all primary quantum numbers to show consistency with observation at the level of Bohr theory. A comparison with the Casimir force per unit area will be made, and an explicit function for the spatial variation of the vacuum density around the atomic nucleus will be derived. This explicit function will be numerically modeled using the industry multi-physics tool, COMSOL(trademark), and the eigenfrequencies for the n = 1 to n = 7 states will be found and compared to expectation.

Four wave mixing as a probe of the vacuum

NASA Astrophysics Data System (ADS)

Tennant, Daniel M.

2016-06-01

Much attention has been paid to the quantum structure of the vacuum. Higher order processes in quantum electrodynamics are strongly believed to cause polarization and even breakdown of the vacuum in the presence of strong fields soon to be accessible in high intensity laser experiments. Less explored consequences of strong field electrodynamics include effects from Born-Infeld type of electromagnetic theories, a nonlinear electrodynamics that follows from classical considerations as opposed to coupling to virtual fluctuations. In this article, I will demonstrate how vacuum four wave mixing has the possibility to differentiate between these two types of vacuum responses: quantum effects on one hand and nonlinear classical extensions on the other.

A study of LC-39 cryogenic systems. Part 1: A study of the vacuum insulated transfer lines at Kennedy Space Center. Part 2: Cooldown pressure surges

NASA Technical Reports Server (NTRS)

Ludtke, P. R.; Voth, R. O.

1971-01-01

The vacuum liquid hydrogen and liquid oxygen transfer lines at Kennedy Space Center were studied to evaluate the feasibility of using a condensing gas such as CO2 inside the vacuum spaces to achieve a condensing-vacuum. The study indicates that at ambient temperature, a maximum vacuum hyphen space pressure of 4000 microns is acceptable for the LH2 transfer lines. In addition, the cooldown procedures for the 14-inch cross-country liquid oxygen line was studied using a simplified mathematical model. Preliminary cooldown times are presented for various heat leak rates to the line and for two vent configurations.

Gravitational baryogenesis in running vacuum models

NASA Astrophysics Data System (ADS)

Oikonomou, V. K.; Pan, Supriya; Nunes, Rafael C.

2017-08-01

We study the gravitational baryogenesis mechanism for generating baryon asymmetry in the context of running vacuum models. Regardless of whether these models can produce a viable cosmological evolution, we demonstrate that they produce a nonzero baryon-to-entropy ratio even if the universe is filled with conformal matter. This is a sound difference between the running vacuum gravitational baryogenesis and the Einstein-Hilbert one, since in the latter case, the predicted baryon-to-entropy ratio is zero. We consider two well known and most used running vacuum models and show that the resulting baryon-to-entropy ratio is compatible with the observational data. Moreover, we also show that the mechanism of gravitational baryogenesis may constrain the running vacuum models.

Cathode surface effects and H.F.-behaviour of vacuum arcs

NASA Astrophysics Data System (ADS)

Fu, Yan Hong

To gain a better understanding of the essential processes occurring during a vacuum arc interruption for the further development of the vacuum arc circuit breaker, cathode spot behavior, current interruption, dielectrical recovery and overvoltage generation are investigated. An experimental study on cathode spot behavior of the DC vacuum arc in relation to cathode surface roughness and a qualitative physical model to interpret the results are reported. An experimental investigation on the High Frequency (HF) current interruption, multiple recognitions and voltage escalation phenomena is reported. A calculation program to predict the level of overvoltages generated by the operation of a vacuum breaker in a realistic single phase circuit is developed. Detailed results are summarized.

Continuous Manufacturing of Nitrocellulose by Magnesium Nitrate Method. Volume 1

DTIC Science & Technology

1979-06-01

enters a scrubber . The scrubber removes entrained acid, water, and NC fines from the air before it enters a Roots water sealed (lobe type) vacuum pump...and is exhausted to the atmosphere. The air enters the bottom of the scrubber and is forced (by vacuum) sequentially through two weir arrangements...the panel from left to right, the Eimco dewatering filter drive, vacuum pressure, receiver, vacuum scrubber , and pump controls may be seen along with

High specific surface area aerogel cryoadsorber for vacuum pumping applications

DOEpatents

Hill, Randal M.; Fought, Eric R.; Biltoft, Peter J.

2000-01-01

A cryogenic pumping system is provided, comprising a vacuum environment, an aerogel sorbent formed from a carbon aerogel disposed within the vacuum environment, and cooling means for cooling the aerogel sorbent sufficiently to adsorb molecules from the vacuum environment onto the aerogel sorbent. Embodiments of the invention include a liquid refrigerant cryosorption pump, a compressed helium cryogenic pump, a cryopanel and a Meissner coil, each of which uses carbon aerogel as a sorbent material.

Cryostat including heater to heat a target

DOEpatents

Pehl, Richard H.; Madden, Norman W.; Malone, Donald F.

1990-01-01

A cryostat is provided which comprises a vacuum vessel; a target disposed within the vacuum vessel; a heat sink disposed within the vacuum vesssel for absorbing heat from the detector; a cooling mechanism for cooling the heat sink; a cryoabsorption mechanism for cryoabsorbing residual gas within the vacuum vessel; and a heater for maintaining the target above a temperature at which the residual gas is cryoabsorbed in the course of cryoabsorption of the residual gas by the cryoabsorption mechanism.

Apollo telescope mount thermal systems unit thermal vacuum test

NASA Technical Reports Server (NTRS)

Trucks, H. F.; Hueter, U.; Wise, J. H.; Bachtel, F. D.

1971-01-01

The Apollo Telescope Mount's thermal systems unit was utilized to conduct a full-scale thermal vacuum test to verify the thermal design and the analytical techniques used to develop the thermal mathematical models. Thermal vacuum test philosophy, test objectives configuration, test monitoring, environment simulation, vehicle test performance, and data correlation are discussed. Emphasis is placed on planning and execution of the thermal vacuum test with particular attention on problems encountered in conducting a test of this maguitude.

Evaluation of a Prototype Hybrid Vacuum Pump to Provide Vacuum-Assisted Suspension for Above-Knee Prostheses

PubMed Central

Major, Matthew J.; Caldwell, Ryan; Fatone, Stefania

2015-01-01

Vacuum-assisted suspension (VAS) of prosthetic sockets utilizes a pump to evacuate air from between the prosthetic liner and socket, and are available as mechanical or electric systems. This technical note describes a hybrid pump that benefits from the advantages of mechanical and electric systems, and evaluates a prototype as proof-of-concept. Cyclical bench testing of the hybrid pump mechanical system was performed using a materials testing system to assess the relationship between compression cycles and vacuum pressure. Phase 1 in vivo testing of the hybrid pump was performed by an able-bodied individual using prosthesis simulator boots walking on a treadmill, and phase 2 involved an above-knee prosthesis user walking with the hybrid pump and a commercial electric pump for comparison. Bench testing of 300 compression cycles produced a maximum vacuum of 24 in-Hg. In vivo testing demonstrated that the hybrid pump continued to pull vacuum during walking, and as opposed to the commercial electric pump, did not require reactivation of the electric system during phase 2 testing. The novelty of the hybrid pump is that while the electric system provides rapid, initial vacuum suspension, the mechanical system provides continuous air evacuation while walking to maintain suspension without reactivation of the electric system, thereby allowing battery power to be reserved for monitoring vacuum levels. PMID:27462383

Load responsive multilayer insulation performance testing

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

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

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

Development of a modified dry curing process for beef.

PubMed

Hayes, J E; Kenny, T A; Ward, P; Kerry, J P

2007-11-01

The development of a dry curing process using physical treatments to promote the diffusion of the cure ingredients was studied. Vacuum pulsing with and without tumbling, continuous vacuum, and tumbling only treatments were compared with a conventional static dry cure control method on beef M. supraspinatus. Vacuum tumble and tumble only treatments gave highest core salt content after 7 days conditioning (3.3% and 3.1%, respectively). All test treatments resulted in higher colour uniformity and lower % cook loss in comparison to control (P<0.001). The control and vacuum pulsed samples were tougher (P<0.001). Vacuum tumble and tumble only treatments gave higher acceptability (P<0.001). Based on these findings for M. supraspinatus, indicating that the vacuum tumble treatments gave the best results, further testing of this method was conducted using the M. biceps femoris in addition to the M. supraspinatus. Cured beef slices were stored in modified atmosphere packs (MAP) (80%N(2):20%CO(2)) for up to 28 day at 4°C. Redness (a(∗), P<0.001) decreased over storage time in M. biceps femoris. Vacuum tumble treatment increased (P<0.05) redness in M. supraspinatus. Results obtained demonstrate the benefits of vacuum tumbling over the other physical treatments as a method for accelerating the dry curing process, producing dry cured beef products with enhanced organoleptic quality and increased yields.

Vacuum Brazing of Accelerator Components

NASA Astrophysics Data System (ADS)

Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

2012-11-01

Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

Antimicrobial susceptibility and internalization of Salmonella Typhimurium in vacuum-tumbled marinated beef products.

PubMed

Pokharel, S; Brooks, J C; Martin, J N; Brashears, M M

2016-12-01

As the incidence of multidrug resistance (MDR) Salmonella enterica serotype Typhimurium is increasing, data regarding the antimicrobial interventions and pathogen internalization in marinated meat products are important. This study evaluated the antimicrobial intervention and internalization of Salm. Typhimurium in marinated beef sirloin steaks. Beef bottom sirloin flaps (IMPS #185A; USDA Select) inoculated (10 8  log 10  CFU ml -1 ) with Salm. Typhimurium were sprayed (lactic acid (4%) and buffered vinegar (2%)) prior to vacuum-tumbled marination (0·35% sodium chloride and 0·45% sodium tripolyphosphate) for 30 min. Pathogen presence after antimicrobial spray, vacuum-tumbled marination, and translocation was determined by direct plating on Xylose Lysine Deoxycholate (XLD) agar with tryptic soy agar (TSA) overlay. The data imply varied internalization and antimicrobial susceptibility pattern of Salm. Typhimurium in marinated meat. Lactic acid (4%) spray (P < 0·0001) and buffered vinegar (2%; P < 0·0001) reduced surface populations of Salm. Typhimurium on inoculated beef sirloin flaps prior to vacuum marination. However, lactic acid treated sirloin flaps had greater reductions (~2 log 10  CFU cm -2 ) than buffered vinegar when compared with control prior to vacuum marination. However, the translocation of Salm. Typhimurium following vacuum marination was not influenced (P < 0·333) by the application of a surface organic acid spray prior to marination. As detailed in the Federal Register FSIS final rule (9 CFR part 317), vacuum-marinated, vacuum-tumbled meat products are not designated as 'mechanically tenderized'. As such, the internalization and potential survival of Salmonella spp. in marinated beef products is a major concern. These results highlight the internalization of pathogens in vacuum-tumbled meat products and emphasize the importance of considering these products as nonintact. Similarly, these data confirm the efficacy and utility of interventions prior to vacuum-tumbled marination. Further research is needed to identify additional strategies to mitigate internalization and translocation of pathogens into vacuum-marinated meat products. © 2016 The Society for Applied Microbiology.

Comparison of home lead dust reduction techniques on hard surfaces: the New Jersey assessment of cleaning techniques trial.

PubMed Central

Rich, David Q; Rhoads, George G; Yiin, Lih-Ming; Zhang, Junfeng; Bai, Zhipeng; Adgate, John L; Ashley, Peter J; Lioy, Paul J

2002-01-01

High efficiency particulate air filter (HEPA) vacuums, which collect particles > 0.3 micro m, and trisodium phosphate (TSP), a detergent claimed to selectively remove lead, have been included in the HUD Guidelines for the Evaluation and Control of Lead Based Paint Hazards in Housing without systematic validation of their effectiveness. At the time the study was initiated, both HEPA vacuums and TSP were relatively expensive, they were not readily found in urban retail centers, and there were environmental concerns about the use and disposal of high-phosphate detergents. A randomized, controlled trial was conducted in urban high-risk homes in northern New Jersey to determine whether a more readily available and less expensive low-phosphate, non-TSP detergent and non-HEPA vacuum could perform as well as TSP and a HEPA vacuum in a cleaning protocol. Homes were randomized to one of three cleaning methods: TSP/HEPA vacuum, TSP/non-HEPA vacuum, or non-TSP/non-HEPA vacuum. Change in log-transformed lead loading was used in mixed models to compare the efficacy of the three cleaning techniques separately for uncarpeted floors, window sills, and window troughs. After we adjusted for baseline lead loading, the non-HEPA vacuum produced larger reductions on hard floors [19%; 95% confidence interval (CI), 3-38%], but the HEPA vacuum produced larger reductions on window sills (22%; 95% CI, 11-32%) and larger reductions on window troughs (16%; 95% CI, -4 to 33%). The non-TSP produced larger reductions on window troughs (21%; 95% CI, -2 to 50%), but TSP produced larger reductions on hard floors (5%; 95% CI, -12 to 19%) and window sills (8%; 95% CI, -5 to 20%). TSP/HEPA produced larger reductions on window sills (28%; 95% CI, 18-37%) and larger reductions on window troughs (2%; 95% CI, -24 to 23%), whereas the non-TSP/non-HEPA method produced larger reductions on hard floors (13%; 95% CI, -5 to 34%). Because neither vacuum nor detergent produced consistent results across surface types, the use of low-phosphate detergents and non-HEPA vacuums in a temporary control measure is supported. PMID:12204823

A Plasma Window for Transmission of Radiation and Particle Beams from Vacuum to Atmosphere for Various Applications

NASA Astrophysics Data System (ADS)

Hershcovitch, Ady

1997-11-01

Many industrial and scientific processes like electron beam melting and welding, material modification by ion implantation, dry etching, and micro-fabrication, as well as generation of synchrotron radiation are performed almost exclusively in vacuum nowadays, since the electron and ion guns and their extractors must be kept at a reasonably high vacuum. Consequently, there are numerous drawbacks, among which are low production rates due to required pumping time, limits the vacuum volume sets on the size of target objects. In a small number of applications like non-vacuum electron beam welding, and various processes involving UV and x-ray radiation, thin vacuum walls or long stages of differential pumping are used. But, the resultant degradations of particle and radiation beams severely limit those applications. A novel apparatus, which utilized a short plasma arc, was successfully used to maintain a pressure of 7.6 x exp(-6) Torr in a vacuum chamber with a 2.36mm aperture to atmosphere, i.e., a plasma was successfully used to "plug" a hole to atmosphere while maintaining a reasonably high vacuum in the chamber. Successful transmission of charged particle beams from a vacuum through the plasma to atmosphere was accomplished. More details can be found in A. Hershcovitch, J. Appl. Physics 78, p. 5283 (1995). In addition to sustaining a vacuum atmosphere interface, the plasma has very strong lensing effect on charged particles. The plasma current generates an azimuthal magnetic field which exerts a radial Lorentz on charged particles moving parallel to the current channel. With proper orientation of the current direction, the Lorentz force is radially inward. This feature can be used to focus in beams to a very small spot size, and to overcome beam dispersion due to scattering by atmospheric atoms and molecules. Relatively hot plasma at the atmosphere boundary rarefies the atmospheric gases to further enhance particle beam propagation to the materials to target. Recent experimental results, with a plasma window coupled to a venturi, show a factor of three further enhancement in vacuum-atmosphere separation.

FOREWORD: 7th Symposium on Vacuum-based Science and Technology (SVBST2013)

NASA Astrophysics Data System (ADS)

Gulbiński, W.

2014-11-01

These are the proceedings of the 7th Symposium on Vacuum based Science and Technology organized in Kołobrzeg (PL) on November 19-21, 2013 by the Institute of Technology and Education, Koszalin University of Technology and the Clausius Tower Society under auspices of the Polish Vacuum Society (PTP) and the German Vacuum Society (DVG) and in collaboration with the BalticNet PlasmaTec and the Society of Vacuum Coaters (SVC). It was accompanied by the 12-th Annual Meeting of the German Vacuum Society. The mission of the Symposium is to provide a forum for presentation and exchange of expertise and research results in the field of vacuum and plasma science. After already six successful meetings organized alternately in Poland and Germany our goal is to continue and foster cooperation within the vacuum and plasma science community. This year, the Rudolf-Jaeckel Prize, awarded by the DVG for outstanding achievements in the field of vacuum based sciences, was presented to Dr Ute Bergner, president of the VACOM Vakuum Komponenten & Messtechnik GmbH and a member of our community. The full-day course organized in the framework of the Educational Program by the Society of Vacuum Coaters (SVC) and entitled: An Introduction to Physical Vapor Deposition (PVD) Processes was held on November 18, 2013 as a satellite event of the Symposium. The instructor was Prof. Ismat Shah from Delaware University (US). The Clausius Session, already traditionally organized during the Symposium was addressed this year to young generation. We invited our young colleagues to attend a series of educational lectures reporting on achievements in graphene science, scanning probe microscopy and plasma science. Lectures were given by: Prof. Jacek Baranowski from the Institute of Electronic Materials Technology in Warsaw, Prof. Teodor Gotszalk from the Wroclaw University of Technology and Prof. Holger Kersten from the Christian Albrechts University in Kiel. The Symposium was accompanied by an industry exhibition attended by the representatives of leading companies offering vacuum equipment, complete solutions for plasma based technology as well as advanced research equipment. Witold Gulbiński Michael Kopnarski Frank Richter Jan Walkowicz

Comparison of home lead dust reduction techniques on hard surfaces: the New Jersey assessment of cleaning techniques trial.

PubMed

Rich, David Q; Rhoads, George G; Yiin, Lih-Ming; Zhang, Junfeng; Bai, Zhipeng; Adgate, John L; Ashley, Peter J; Lioy, Paul J

2002-09-01

High efficiency particulate air filter (HEPA) vacuums, which collect particles > 0.3 micro m, and trisodium phosphate (TSP), a detergent claimed to selectively remove lead, have been included in the HUD Guidelines for the Evaluation and Control of Lead Based Paint Hazards in Housing without systematic validation of their effectiveness. At the time the study was initiated, both HEPA vacuums and TSP were relatively expensive, they were not readily found in urban retail centers, and there were environmental concerns about the use and disposal of high-phosphate detergents. A randomized, controlled trial was conducted in urban high-risk homes in northern New Jersey to determine whether a more readily available and less expensive low-phosphate, non-TSP detergent and non-HEPA vacuum could perform as well as TSP and a HEPA vacuum in a cleaning protocol. Homes were randomized to one of three cleaning methods: TSP/HEPA vacuum, TSP/non-HEPA vacuum, or non-TSP/non-HEPA vacuum. Change in log-transformed lead loading was used in mixed models to compare the efficacy of the three cleaning techniques separately for uncarpeted floors, window sills, and window troughs. After we adjusted for baseline lead loading, the non-HEPA vacuum produced larger reductions on hard floors [19%; 95% confidence interval (CI), 3-38%], but the HEPA vacuum produced larger reductions on window sills (22%; 95% CI, 11-32%) and larger reductions on window troughs (16%; 95% CI, -4 to 33%). The non-TSP produced larger reductions on window troughs (21%; 95% CI, -2 to 50%), but TSP produced larger reductions on hard floors (5%; 95% CI, -12 to 19%) and window sills (8%; 95% CI, -5 to 20%). TSP/HEPA produced larger reductions on window sills (28%; 95% CI, 18-37%) and larger reductions on window troughs (2%; 95% CI, -24 to 23%), whereas the non-TSP/non-HEPA method produced larger reductions on hard floors (13%; 95% CI, -5 to 34%). Because neither vacuum nor detergent produced consistent results across surface types, the use of low-phosphate detergents and non-HEPA vacuums in a temporary control measure is supported.

Gage measures total radiation, including vacuum UV, from ionized high-temperature gases

NASA Technical Reports Server (NTRS)

Wood, A. D.

1969-01-01

Transient-heat transfer gage measures the total radiation intensity from vacuum ultraviolet and ionized high temperature gases. The gage includes a sensitive piezoelectric crystal that is completely isolated from any ionized flow and vacuum ultraviolet irradiation.

14 CFR 25.1433 - Vacuum systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vacuum systems. 25.1433 Section 25.1433 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There...

Properties data for opening the Galileo's partially unfurled main antenna

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa; Pepper, Stephen V.

1992-01-01

An investigation was conducted into the friction and wear behavior of both unlubricated and dry-film-lubricated (Tiolube 460) titanium alloy (Ti-6Al-4V) in contact with an uncoated high-nickel-content superalloy (Inconel 718) both in vacuum and in air. The acquisition of friction and wear data for this sliding couple was motivated by the need for input data for the 'antenna stuck ribs model' effort to free Galileo's High Gain Antenna. The results of the investigation indicate that galling occurred in the unlubricated system in vacuum and that the coefficient of friction increased to 1.2. The abnormally high friction (1.45) was observed when relatively large wear debris clogged at the sliding interface. The coefficient of friction for the dry-film-lubricated system in vacuum is 0.04, while the value in air is 0.13. The endurance life of the dry-film lubricant is about three orders of magnitude greater in vacuum than in air. The worn surfaces of the dry-film-lubricated Ti-6Al-4V pin and Inconel 718 disk first run in humid air and then rerun in vacuum was completely different from that of the pin and disk run only in vacuum. When galling occurred in the humid-air and vacuum contact, coefficient of friction rose to 0.32 when sliding in humid air and to 1.4 when sliding in vacuum. The galling was accompanied by severe surface damage and extensive transfer of the Ti-6Al-4V to the Inconel 718, or vice versa. When spalling occurred in the dry-film-lubricated Ti-6Al-4V pin run only in vacuum, the coefficient of friction rose to 0.36 or greater. The wear damage caused by spalling can self-heal when rerun in vacuum - the coefficient of friction decreased to 0.05. The friction and wear data obtained can be used for the 'antenna stuck ribs model' effort to free Galileo's high gain antenna.

Vacuum-assisted venous return reduces blood usage.

PubMed

Banbury, Michael K; White, Jennifer A; Blackstone, Eugene H; Cosgrove, Delos M

2003-09-01

To determine whether vacuum-assisted venous return has clinical advantages over conventional gravity drainage apart from allowing the use of smaller cannulas and shorter tubing. A total of 150 valve operations were performed at our institution between February and July 1999 using vacuum-assisted venous return with small venous cannulas connected to short tubing. These were compared with (1) 83 valve operations performed between April 1997 and January 1998 using the initial version of vacuum-assisted venous return, and (2) 124 valve operations performed between January and April of 1997 using conventional gravity drainage. Priming volume, hematocrit value, red blood cell usage, and total blood product usage were compared multivariably. These comparisons were covariate and propensity adjusted for dissimilarities between the groups and confirmed by propensity-matched pairs analysis. Priming volume was 1.4 +/- 0.4 L for small-cannula vacuum-assisted venous return, 1.7 +/- 0.4 L for initial vacuum-assisted venous return, and 2.0 +/- 0.4 L for gravity drainage (P <.0001). Smaller priming resulted in higher hematocrit values both at the beginning of cardiopulmonary bypass (27% +/- 5% compared with 26% +/- 4% and 25% +/- 4%, respectively, P <.0001) and at the end (30% +/- 4% compared with 28% +/- 4% and 27% +/- 4%, respectively, P <.0001). Red cell transfusions were used in 17% of the patients having small-cannula vacuum-assisted venous return, 27% of the initial patients having vacuum-assisted venous return, and 37% of the patients having gravity drainage (P =.001); total blood product usage was 19%, 27%, and 39%, respectively (P =.002). Although ministernotomy also was associated with reduced blood product usage (P <.004), propensity matching on type of sternotomy confirmed the association of vacuum-assisted venous return with lowered blood product usage. Vacuum-assisted venous return results in (1) higher hematocrit values during cardiopulmonary bypass and (2) decreased red cell and total blood product usage.

Vacuum system of the cyclotrons in VECC, Kolkata

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

Roy, Anindya; Bhole, R.B.; Akhtar, J.

2011-07-01

The vacuum system of the K=130 Room Temperature Cyclotron (RTC) (operational since 1978) has been recently modernized and the same of the K{sub bend}=520 Superconducting Cyclotron (SCC), currently under commissioning, is being deployed for remote monitoring and control. The vacuum system of RTC is designed to achieve and maintain vacuum level of 2 X 10{sup -6} mbar inside 23 m{sup 3} volume of Resonator tank and DEE tank. This has been upgraded by replacing several valves, Freon units, gauges and pumps. The relay based manual control system has been replaced by PLC based automated system. The SCC vacuum system alsomore » has an elaborate arrangement comprising of turbo molecular pumping modules with associated isolation valves and characteristic gauges. This paper describes essential elements, typically used to obtain high (1X10{sup -7} mbar) vacuum using rotary pumps, diffusion pumps and cold traps/turbo-molecular pumps and other system components such as valves, gauges and baffles. The supervisory control methodology/scheme of both the vacuum systems, developed in-house using EPICS (Experimental Physics and Industrial Control System), a standard open-source software tool for designing distributed control system, is also elaborated here. (author)« less

Extension of the shelf life of prawns (Penaeus japonicus) by vacuum packaging and high-pressure treatment.

PubMed

López-Caballero, M E; Pérez-Mateos, M; Borderías, J A; Montero, P

2000-10-01

The present study has investigated the application of high pressures (200 and 400 MPa) in chilled prawn tails, both conventionally stored (air) and vacuum packaged. Vacuum packaging and high-pressure treatment did extend the shelf life of the prawn samples, although it did affect muscle color very slightly, giving it a whiter appearance. The viable shelf life of 1 week for the air-stored samples was extended to 21 days in the vacuum-packed samples, 28 days in the samples treated at 200 MPa, and 35 days in the samples pressurized at 400 MPa. Vacuum packaging checked the onset of blackening, whereas high-pressure treatment aggravated the problem. From a microbiological point of view, batches conventionally stored reached about 6 log CFU/g or even higher at 14 days. Similar figures were reached in total number of bacteria in vacuum-packed samples and in pressurized at 200-MPa samples at 21 days. When samples were pressurized at 400 MPa, total numbers of bacteria were below 5.5 log CFU/g at 35 days of storage. Consequently, a combination of vacuum packaging and high-pressure treatment would appear to be beneficial in prolonging freshness and preventing spotting.

Dyonic Flux Tube Structure of Nonperturbative QCD Vacuum

NASA Astrophysics Data System (ADS)

Chandola, H. C.; Pandey, H. C.

We study the flux tube structure of the nonperturbative QCD vacuum in terms of its dyonic excitations by using an infrared effective Lagrangian and show that the dyonic condensation of QCD vacuum has a close connection with the process of color confinement. Using the fiber bundle formulation of QCD, the magnetic symmetry condition is presented in a gauge covariant form and the gauge potential has been constructed in terms of the magnetic vectors on global sections. The dynamical breaking of the magnetic symmetry has been shown to lead the dyonic condensation of QCD vacuum in the infrared energy sector. Deriving the asymptotic solutions of the field equations in the dynamically broken phase, the dyonic flux tube structure of QCD vacuum is explored which has been shown to lead the confinement parameters in terms of the vector and scalar mass modes of the condensed vacuum. Evaluating the charge quantum numbers and energy associated with the dyonic flux tube solutions, the effect of electric excitation of monopole is analyzed using the Regge slope parameter (as an input parameter) and an enhancement in the dyonic pair correlations and the confining properties of QCD vacuum in its dyonically condensed mode has been demonstrated.

Phacoemulsification tip vacuum pressure: Comparison of 4 devices.

PubMed

Payne, Marielle; Georgescu, Dan; Waite, Aaron N; Olson, Randall J

2006-08-01

To determine the vacuum pressure generated by 4 phacoemulsification devices measured at the phacoemulsification tip. University ophthalmology department. The effective vacuum pressures generated by the Sovereign (AMO), Millennium (Bausch & Lomb), Legacy AdvanTec (Alcon Laboratories), and Infiniti (Alcon Laboratories) phacoemulsification machines were measured with a device that isolated the phacoemulsification tip in a chamber connected to a pressure gauge. The 4 machines were tested at multiple vacuum limit settings, and the values were recorded after the foot pedal was fully depressed and the pressure had stabilized. The AdvanTec and Infiniti machines were tested with and without occlusion of the Aspiration Bypass System (ABS) side port (Alcon Laboratories). The Millennium machine was tested using venturi and peristaltic pumps. The machines generated pressures close to the expected at maximum vacuum settings between 100 mm Hg and 500 mm Hg with few intermachine variations. There was no significant difference between pressures generated using 19- or 20-gauge tips (Millennium and Sovereign). The addition of an ABS side port decreased vacuum by a mean of 12.1% (P < .0001). Although there were some variations in vacuum pressures among phacoemulsification machines, particularly when an aspiration bypass tip was used, these discrepancies are probably not clinically significant.

Diffraction-limited storage-ring vacuum technology

PubMed Central

Al-Dmour, Eshraq; Ahlback, Jonny; Einfeld, Dieter; Tavares, Pedro Fernandes; Grabski, Marek

2014-01-01

Some of the characteristics of recent ultralow-emittance storage-ring designs and possibly future diffraction-limited storage rings are a compact lattice combined with small magnet apertures. Such requirements present a challenge for the design and performance of the vacuum system. The vacuum system should provide the required vacuum pressure for machine operation and be able to handle the heat load from synchrotron radiation. Small magnet apertures result in the conductance of the chamber being low, and lumped pumps are ineffective. One way to provide the required vacuum level is by distributed pumping, which can be realised by the use of a non-evaporable getter (NEG) coating of the chamber walls. It may not be possible to use crotch absorbers to absorb the heat from the synchrotron radiation because an antechamber is difficult to realise with such a compact lattice. To solve this, the chamber walls can work as distributed absorbers if they are made of a material with good thermal conductivity, and distributed cooling is used at the location where the synchrotron radiation hits the wall. The vacuum system of the 3 GeV storage ring of MAX IV is used as an example of possible solutions for vacuum technologies for diffraction-limited storage rings. PMID:25177979

Vacuum packing: a model system for laboratory-scale silage fermentations.

PubMed

Johnson, H E; Merry, R J; Davies, D R; Kell, D B; Theodorou, M K; Griffith, G W

2005-01-01

To determine the utility of vacuum-packed polythene bags as a convenient, flexible and cost-effective alternative to fixed volume glass vessels for lab-scale silage studies. Using perennial ryegrass or red clover forage, similar fermentations (as assessed by pH measurement) occurred in glass tube and vacuum-packed silos over a 35-day period. As vacuum-packing devices allow modification of initial packing density, the effect of four different settings (initial packing densities of 0.397, 0.435, 0.492 and 0.534 g cm(-3)) on the silage fermentation over 16 days was examined. Significant differences in pH decline and lactate accumulation were observed at different vacuum settings. Gas accumulation was apparent within all bags and changes in bag volume with time was observed to vary according to initial packing density. Vacuum-packed silos do provide a realistic model system for lab-scale silage fermentations. Use of vacuum-packed silos holds potential for lab-scale evaluations of silage fermentations, allowing higher throughput of samples, more consistent packing as well as the possibility of investigating the effects of different initial packing densities and use of different wrapping materials.

The Diagnostic Value of the Vacuum Phenomenon during Hip Arthroscopy

PubMed Central

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

2011-01-01

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

Analysis on the impact of FBG reflectance spectrum with different optical fiber connection in vacuum thermal environment

NASA Astrophysics Data System (ADS)

Zhang, Jingchuan; Zhang, Wen; Lv, Jianfeng; Liang, Shuo; Wang, Lei; Li, Xiyuan

2018-01-01

To satisfy the application of fiber grating sensor technology in high vacuum thermal environment, FBG on sleeve compactly single model fiber with two typical different kind of connection such as fiber splicing and optical fiber connector are researched. Influence of the different connection to the characteristic of FBG reflectance spectrum in high vacuum thermal environment is analyzed and verified. First, experimental program of influence on FBG reflection spectrum characteristics is designed. Then, a hardware-in-the-loop detection platform is set up. Finally, the influence of temperature and vacuum on the reflection peak power of FBG with two typical different connections under high vacuum thermal environment is studied and verified. Experimental results indicate that: when vacuum varied from normal pressure to 10-4Pa level and then return to normal pressure, temperature of two different single-mode optical fiber connection dropped to -196 °C from room temperature and then returned to room temperature, after 224 hours, the peak power of the FBG reflectance spectrum did not change. It provided the experimental basis for the application of optical fiber sensing technology in high vacuum (pressure about 10-4Pa level) and thermal environment (-196 °C temperature cycle).

The Diagnostic Value of the Vacuum Phenomenon during Hip Arthroscopy.

PubMed

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

2011-01-01

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

Targeted Cleaning.

ERIC Educational Resources Information Center

Frank, David J.

1998-01-01

Discusses the creation of an effective carpet vacuuming program by combining area usage assessment and vacuuming requirements with a scheduling plan. Also explains vacuum cleaner suction and filtration and how it makes custodian work more efficient. A complementary article discusses creating an effective floor-maintenance plan for resilient…

Portable mass spectrometer with one or more mechanically adjustable electrostatic sectors and a mechanically adjustable magnetic sector all mounted in a vacuum chamber

DOEpatents

Andresen, B.D.; Eckels, J.D.; Kimmons, J.F.; Martin, W.H.; Myers, D.W.; Keville, R.F.

1992-10-06

A portable mass spectrometer is described having one or more electrostatic focusing sectors and a magnetic focusing sector, all of which are positioned inside a vacuum chamber, and all of which may be adjusted via adjustment means accessible from outside the vacuum chamber. Mounting of the magnetic sector entirely within the vacuum chamber permits smaller magnets to be used, thus permitting reductions in both weight and bulk. 13 figs.

Cryostat including heater to heat a target

DOEpatents

Pehl, R.H.; Madden, N.W.; Malone, D.F.

1990-09-11

A cryostat is provided which comprises a vacuum vessel; a target disposed within the vacuum vessel; a heat sink disposed within the vacuum vessel for absorbing heat from the detector; a cooling mechanism for cooling the heat sink; a cryoabsorption mechanism for cryoabsorbing residual gas within the vacuum vessel; and a heater for maintaining the target above a temperature at which the residual gas is cryoabsorbed in the course of cryoabsorption of the residual gas by the cryoabsorption mechanism. 2 figs.

Self contained, independent, in-vacuum spinner motor

DOEpatents

Ayers, Marion J.

2002-01-01

An independent, self contained apparatus for operation within a vacuum chamber. A sealed enclosure is located in the chamber. The enclosure contains its own atmosphere independent of the vacuum in the chamber. A motor, power unit, and controls are located entirely within the enclosure. They do not have a direct structural connection outside of the enclosure in any way that would effect the atmosphere within the enclosure. The motor, power unit, and controls drive a spinner plate located outside the enclosure but within the vacuum chamber.

The vacuum system reform and test of the super-critical 600mw unit

NASA Astrophysics Data System (ADS)

Yan, Tao; Wan, Zhonghai; Lu, Jin; Chen, Wen; Cai, Wen

2017-11-01

The deficiencies of the designed vacuum system of the super-critical unit is pointed out in this paper, and then it is reformed by the steam ejector. The experimental results show that the vacuum of the condenser can be improved, the coal consumption can be reduced and the plant electricity consumption can be lowered dramatically at a small cost of the steam energy consumption. Meanwhile, the water-ring vacuum pumps cavitation problems can be solved.

Rapid Ascent Simulation at NASA-MSFC

NASA Technical Reports Server (NTRS)

Sisco, Jimmy D.

2004-01-01

The Environmental Test Facility (ETF), located at NASA-Marshall Space Flight Center, Huntsville, Alabama, has provided thermal vacuum testing for several major programs since the 1960's. The ETF consists of over 13 thermal vacuum chambers sized and configured to handle the majority of test payloads. The majority of tests require a hard vacuum with heating and cryogenics. NASA's Return-to-Flight program requested testing to simulate a launch from the ground to flight using vacuum, heating and cryogenics. This paper describes an effective method for simulating a launch.

A Study of Alternative Approaches to Produce Obscuring Smoke with JP-8 in Vehicle Engine Exhaust Smoke Systems (VEESS)

DTIC Science & Technology

1989-12-01

fuel. Full D 2887 distillation data are also shown in the Appendix. Fractionation ADparatus - The glass vacuum distillation apparatus used was from a...liter - 3-neck glass round bottom flask 2. 120 cm (4 ft), 50-mm diameter vacuum -jacketed column packed with No. 2918 Helipak coils 12 TABLE 3. ASTM D...swinging bucket for variable reflux ratios and an integral condenser, all of which are vacuum jacketed 4. Product receiver of 1-liter capacity, vacuum

[Dual chamber safety vacuum--initial experiences with a new suction cup].

PubMed

Korell, M; King, S; Hepp, H

1994-06-01

The main problem with vacuum extraction methods, alongside the cephalhaematoma produced, is the premature separation of the suction cup under traction, since the resulting sudden change in pressure can lead to severe intra-cerebral damage to the child. To reduce the risk of vaginal operative delivery, a new double-chamber safety vacuum extractor has been developed by Hepp/King. The basic feature of this instrument is an additional chamber with a thin overlapping area, which surrounds the actual suction cup and serves as a safety vacuum. If the suction cup starts to slip, the external vacuum is released and sounds an alarm. In addition, the inner vacuum has been designed to be convex and to reduce the volume of scalp, which is sucked into the vacuum, thus reducing the size of the cephalhaematoma produced. First experiences in clinical use demonstrated the reliability of the early warning signal, if the direction of traction is false or the applied traction is too strong. The inner vacuum remains constant at 0.8 atu, so that with care, the extraction can continue without interruption. We have used the new instrument in 18 deliveries. In 15 cases, the indication was failure to progress into the second stage of labour; in one case history of retinal detachment and in two cases signs of foetal asphyxia. In all cases, the child was delivered following one or two contractions with traction, without losing the vacuum. The average weight of the newborn was 3566 g. As expected, the cephalohaematoma produced was very much smaller than usual. Further clinical trials are necessary before the value of this new instrument can be assessed.

The moisture outgassing kinetics of a silica reinforced polydimethylsiloxane

NASA Astrophysics Data System (ADS)

Sharma, H. N.; McLean, W.; Maxwell, R. S.; Dinh, L. N.

2016-09-01

A silica-filled polydimethylsiloxane (PDMS) composite M9787 was investigated for potential outgassing in a vacuum/dry environment with the temperature programmed desorption/reaction method. The outgassing kinetics of 463 K vacuum heat-treated samples, vacuum heat-treated samples which were subsequently re-exposed to moisture, and untreated samples were extracted using the isoconversional and constrained iterative regression methods in a complementary fashion. Density functional theory (DFT) calculations of water interactions with a silica surface were also performed to provide insight into the structural motifs leading to the obtained kinetic parameters. Kinetic analysis/model revealed that no outgassing occurs from the vacuum heat-treated samples in subsequent vacuum/dry environment applications at room temperature (˜300 K). The main effect of re-exposure of the vacuum heat-treated samples to a glove box condition (˜30 ppm by volume of H2O) for even a couple of days was the formation, on the silica surface fillers, of ˜60 ppm by weight of physisorbed and loosely bonded moisture, which subsequently outgasses at room temperature in a vacuum/dry environment in a time span of 10 yr. However, without any vacuum heat treatment and even after 1 h of vacuum pump down, about 300 ppm by weight of H2O would be released from the PDMS in the next few hours. Thereafter the outgassing rate slows down substantially. The presented methodology of using the isoconversional kinetic analysis results and some appropriate nature of the reaction as the constraints for more accurate iterative regression analysis/deconvolution of complex kinetic spectra, and of checking the so-obtained results with first principle calculations such as DFT can serve as a template for treating other complex physical/chemical processes as well.

Gas propagation in a liquid helium cooled vacuum tube following a sudden vacuum loss

NASA Astrophysics Data System (ADS)

Dhuley, Ram C.

This dissertation describes the propagation of near atmospheric nitrogen gas that rushes into a liquid helium cooled vacuum tube after the tube suddenly loses vacuum. The loss-of-vacuum scenario resembles accidental venting of atmospheric air to the beam-line of a superconducting radio frequency particle accelerator and is investigated to understand how in the presence of condensation, the in-flowing air will propagate in such geometry. In a series of controlled experiments, room temperature nitrogen gas (a substitute for air) at a variety of mass flow rates was vented to a high vacuum tube immersed in a bath of liquid helium. Pressure probes and thermometers installed on the tube along its length measured respectively the tube pressure and tube wall temperature rise due to gas flooding and condensation. At high mass in-flow rates a gas front propagated down the vacuum tube but with a continuously decreasing speed. Regression analysis of the measured front arrival times indicates that the speed decreases nearly exponentially with the travel length. At low enough mass in-flow rates, no front propagated in the vacuum tube. Instead, the in-flowing gas steadily condensed over a short section of the tube near its entrance and the front appeared to `freeze-out'. An analytical expression is derived for gas front propagation speed in a vacuum tube in the presence of condensation. The analytical model qualitatively explains the front deceleration and flow freeze-out. The model is then simplified and supplemented with condensation heat/mass transfer data to again find the front to decelerate exponentially while going away from the tube entrance. Within the experimental and procedural uncertainty, the exponential decay length-scales obtained from the front arrival time regression and from the simplified model agree.

Low vacuum and discard tubes reduce hemolysis in samples drawn from intravenous catheters.

PubMed

Heiligers-Duckers, Connie; Peters, Nathalie A L R; van Dijck, Jose J P; Hoeijmakers, Jan M J; Janssen, Marcel J W

2013-08-01

In-vitro hemolysis is a great challenge to emergency departments where blood is drawn from intravenous catheters (IVCs). Although high quality samples can be obtained by straight needle venipuncture, IVCs are preferred for various reasons. The aim of this study was to identify blood collection practices that reduce hemolysis while using IVC. The study was conducted at an emergency department where blood is drawn in ≥ 90% of patients from IVC. Hemolysis, measured spectrophotometrically, was compared between syringe and vacuum tubes. The following practices were tested in combination with vacuum collection; a Luer-slip adapter, a Luer-lock adapter, discard tubes and low vacuum tubes. Each intervention lasted 1 week and retrieved 154 to 297 samples. As reference, hemolysis was also measured in vacuum tubes retrieved from departments where only straight needle venipuncture is performed. Vacuum collection led to more hemolytic samples compared with syringe tubes (24% versus 16% respectively, p=0.008). No difference in hemolysis was observed between the Luer-slip and the Luer-lock adapter. The use of discard (17% hemolytic, p=0.045) and low vacuum tubes (12% hemolytic, p<0.001) substantially decreased hemolysis. None of the interventions reduced the hemolysis rate to the level observed when drawing blood by straight needle venipuncture (3%, p<0.02). In summary, both discard and low vacuum tubes reduce hemolysis while drawing blood from IVC. Of these practices the use of a low vacuum tube is preferred considering the less volume of blood and the amount of tubes drawn. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

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

Sharma, H. N.; McLean, W.; Maxwell, R. S.

We investigated a silica-filled polydimethylsiloxane (PDMS) composite M9787 for potential outgassing in a vacuum/dry environment with the temperature programmed desorption/reaction method. The outgassing kinetics of 463 K vacuum heat-treated samples, vacuum heat-treated samples which were subsequently re-exposed to moisture, and untreated samples were extracted using the isoconversional and constrained iterative regression methods in a complementary fashion. Density functional theory (DFT) calculations of water interactions with a silica surface were also performed to provide insight into the structural motifs leading to the obtained kinetic parameters. Kinetic analysis/model revealed that no outgassing occurs from the vacuum heat-treated samples in subsequent vacuum/dry environmentmore » applications at room temperature (~300 K). Moreover, the main effect of re-exposure of the vacuum heat-treated samples to a glove box condition (~30 ppm by volume of H 2O) for even a couple of days was the formation, on the silica surface fillers, of ~60 ppm by weight of physisorbed and loosely bonded moisture, which subsequently outgasses at room temperature in a vacuum/dry environment in a time span of 10 yr. However, without any vacuum heat treatment and even after 1 h of vacuum pump down, about 300 ppm by weight of H 2O would be released from the PDMS in the next few hours. Thereafter the outgassing rate slows down substantially. Our presented methodology of using the isoconversional kinetic analysis results and some appropriate nature of the reaction as the constraints for more accurate iterative regression analysis/deconvolution of complex kinetic spectra, and of checking the so-obtained results with first principle calculations such as DFT can serve as a template for treating other complex physical/chemical processes as well.« less

Development and Testing of an ISRU Soil Mechanics Vacuum Test Facility

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie E.; Wilkinson, R. Allen

2014-01-01

For extraterrestrial missions, earth based testing in relevant environments is key to successful hardware development. This is true for both early component level development and system level integration. For In-Situ Resource Utilization (ISRU) on the moon, hardware must interface with the surface material, or regolith, in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, properly conditioned bed of lunar regolith simulant. However, in earth-based granular media, such as lunar regolith simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. A mid-size chamber (3.66 m tall, 1.5 m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64 m deep by 0.914 m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types were used. Data obtained from an electric cone penetrometer can be used to determine strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off-gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5 Torr, regardless of the pump rate. The slow off-gassing of the soil at low pressure lead to long test times; a full week to reach 10(exp -5) Torr. Robotic soil manipulation would enable multiple ISRU hardware test within the same vacuum cycle. The feasibility of a robotically controlled auger and tamper was explored at vacuum conditions.

ISRU Soil Mechanics Vacuum Facility: Soil Bin Preparation and Simulant Strength Characterization

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie; Wilkinson, Allen

2012-01-01

Testing in relevant environments is key to exploration mission hardware development. This is true on both the component level (in early development) and system level (in late development stages). During ISRU missions the hardware will interface with the soil (digging, roving, etc) in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, conditioned simulant bed. However, in earth-based granular media, such as lunar soil simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. The Vacuum Facility #13, a mid-size chamber (3.66m tall, 1.5m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64m deep by 0.914m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types have been used. An electric cone penetrometer was used to measure simulant strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5Torr, regardless of the pump rate. However, slow off gassing of the soil lead to long test times, a full week, to reach 10-5Torr. This work highlights the need for robotic machine-simulant hardware and operations in vacuum to expeditiously perform (sub-)systems tests.

Evaluation of sample hemolysis in blood collected by S-Monovette using vacuum or aspiration mode.

PubMed

Lippi, Giuseppe; Avanzini, Paola; Musa, Roberta; Sandei, Franca; Aloe, Rosalia; Cervellin, Gianfranco

2013-01-01

In vitro hemolysis can be induced by several biological and technical sources, and may be worsened by forced aspiration of blood in vacuum tubes. This study was aimed to compare the probability of hemolysis by drawing blood with a commercial evacuated blood collection tube, and S-Monovette used either in the "vacuum" or "aspiration" mode. The study population consisted in 20 healthy volunteers. A sample was drawn into 4.0 mL BD Vacutainer serum tube from a vein of one upper arm. Two other samples were drawn with a second venipuncture from a vein of the opposite arm, into 4.0 mL S-Monovette serum tubes, by both vacuum an aspiration modes. After separation, serum potassium, lactate dehydrogenase (LD) and hemolysis index (HI) were tested on Beckman Coulter DxC. In no case the HI exceed the limit of significant hemolysis. As compared with BD Vacutainer, no significant differences were observed for potassium and LD using S-Monovette with vacuum method. Significant increased values of both parameters were however found in serum collected into BD Vacutainer and S-Monovette by vacuum mode, compared to serum drawn by S-Monovette in aspiration mode. The mean potassium bias was 2.2% versus BD Vacutainer and 2.4% versus S-Monovette in vacuum mode, that of LD was 2.7% versus BD Vacutainer and 2.1% versus S-Monovette in vacuum mode. None of these variations exceeded the allowable total error. Although no significant macro-hemolysis was observed with any collection system, the less chance of producing micro-hemolysis by S-Monovette in aspiration mode suggest that this device may be used when a difficult venipuncture combined with the vacuum may increase the probability of spurious hemolysis.

The moisture outgassing kinetics of a silica reinforced polydimethylsiloxane

DOE PAGES

Sharma, H. N.; McLean, W.; Maxwell, R. S.; ...

2016-09-21

We investigated a silica-filled polydimethylsiloxane (PDMS) composite M9787 for potential outgassing in a vacuum/dry environment with the temperature programmed desorption/reaction method. The outgassing kinetics of 463 K vacuum heat-treated samples, vacuum heat-treated samples which were subsequently re-exposed to moisture, and untreated samples were extracted using the isoconversional and constrained iterative regression methods in a complementary fashion. Density functional theory (DFT) calculations of water interactions with a silica surface were also performed to provide insight into the structural motifs leading to the obtained kinetic parameters. Kinetic analysis/model revealed that no outgassing occurs from the vacuum heat-treated samples in subsequent vacuum/dry environmentmore » applications at room temperature (~300 K). Moreover, the main effect of re-exposure of the vacuum heat-treated samples to a glove box condition (~30 ppm by volume of H 2O) for even a couple of days was the formation, on the silica surface fillers, of ~60 ppm by weight of physisorbed and loosely bonded moisture, which subsequently outgasses at room temperature in a vacuum/dry environment in a time span of 10 yr. However, without any vacuum heat treatment and even after 1 h of vacuum pump down, about 300 ppm by weight of H 2O would be released from the PDMS in the next few hours. Thereafter the outgassing rate slows down substantially. Our presented methodology of using the isoconversional kinetic analysis results and some appropriate nature of the reaction as the constraints for more accurate iterative regression analysis/deconvolution of complex kinetic spectra, and of checking the so-obtained results with first principle calculations such as DFT can serve as a template for treating other complex physical/chemical processes as well.« less

Vacuum-Induction, Vacuum-Arc, and Air-Induction Melting of a Complex Heat-Resistant Alloy

NASA Technical Reports Server (NTRS)

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

1959-01-01

The relative hot-workability and creep-rupture properties at 1600 F of a complex 55Ni-20Cr-15Co-4Mo-3Ti-3Al alloy were evaluated for vacuum-induction, vacuum-arc, and air-induction melting. A limited study of the role of oxygen and nitrogen and the structural effects in the alloy associated with the melting process was carried out. The results showed that the level of boron and/or zirconium was far more influential on properties than the melting method. Vacuum melting did reduce corner cracking and improve surface during hot-rolling. It also resulted in more uniform properties within heats. The creep-rupture properties were slightly superior in vacuum heats at low boron plus zirconium or in heats with zirconium. There was little advantage at high boron levels and air heats were superior at high levels of boron plus zirconium. Vacuum heats also had fewer oxide and carbonitride inclusions although this was a function of the opportunity for separation of the inclusions from high oxygen plus nitrogen heats. The removal of phosphorous by vacuum melting was not found to be related to properties. Oxygen plus nitrogen appeared to increase ductility in creep-rupture tests suggesting that vacuum melting removes unidentified elements detrimental to ductility. Oxides and carbonitrides in themselves did not initiate microcracks. Carbonitrides in the grain boundaries of air heats did initiate microcracks. The role of microcracking from this source and as a function of oxygen and nitrogen content was not clear. Oxygen and nitrogen did intensify corner cracking during hot-rolling but were not responsible for poor surface which resulted from rolling heats melted in air.

Atmospheres and spectra of strongly magnetized neutron stars - II. The effect of vacuum polarization

NASA Astrophysics Data System (ADS)

Ho, Wynn C. G.; Lai, Dong

2003-01-01

We study the effect of vacuum polarization on the atmosphere structure and radiation spectra of neutron stars with surface magnetic fields B= 1014-1015 G, as appropriate for magnetars. Vacuum polarization modifies the dielectric property of the medium and gives rise to a resonance feature in the opacity; this feature is narrow and occurs at a photon energy that depends on the plasma density. Vacuum polarization can also induce resonant conversion of photon modes via a mechanism analogous to the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism for neutrino oscillation. We construct atmosphere models in radiative equilibrium with an effective temperature of a few ×106 K by solving the full radiative transfer equations for both polarization modes in a fully ionized hydrogen plasma. We discuss the subtleties in treating the vacuum polarization effects in the atmosphere models and present approximate solutions to the radiative transfer problem which bracket the true answer. We show from both analytic considerations and numerical calculations that vacuum polarization produces a broad depression in the X-ray flux at high energies (a few keV <~E<~ a few tens of keV) as compared to models without vacuum polarization; this arises from the density dependence of the vacuum resonance feature and the large density gradient present in the atmosphere. Thus the vacuum polarization effect softens the high-energy tail of the thermal spectrum, although the atmospheric emission is still harder than the blackbody spectrum because of the non-grey opacities. We also show that the depression of continuum flux strongly suppresses the equivalent width of the ion cyclotron line and therefore makes the line more difficult to observe.

A step towards long-wavelength protein crystallography: subjecting protein crystals to a vacuum

PubMed Central

Panjikar, Santosh; Thomsen, Lars; O’Donnell, Kane Michael; Riboldi-Tunnicliffe, Alan

2015-01-01

Using the UHV experimental endstation on the soft X-ray beamline at the Australian Synchrotron, lysozyme and proteinase K crystals have been exposed to a vacuum of 10−5 mbar, prior to flash-cooling in a bath of liquid nitrogen. Subsequent data collection on the MX2 beamline at the Australian Synchrotron demonstrated that, for lysozyme and proteinase K, it is possible to subject these mounted crystals to a vacuum pressure of 10−5 mbar without destroying the crystal lattice. Despite the lower data quality of the vacuum-pumped crystals compared with control crystals, it is demonstrated that the protein crystals can survive in a vacuum under suitable conditions. PMID:26089765

Mass spectrometer vacuum housing and pumping system

DOEpatents

Coutts, G.W.; Bushman, J.F.; Alger, T.W.

1996-07-23

A vacuum housing and pumping system is described for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof. 7 figs.

Mass spectrometer vacuum housing and pumping system

DOEpatents

Coutts, Gerald W.; Bushman, John F.; Alger, Terry W.

1996-01-01

A vacuum housing and pumping system for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof.

Dynamical emergence of the Universe into the false vacuum

NASA Astrophysics Data System (ADS)

Rafelski, Johann; Birrell, Jeremiah

2015-11-01

We study how the hot Universe evolves and acquires the prevailing vacuum state, demonstrating that in specific conditions which are believed to apply, the Universe becomes frozen into the state with the smallest value of Higgs vacuum field v=langle hrangle, even if this is not the state of lowest energy. This supports the false vacuum dark energy Λ-model. Under several likely hypotheses we determine the temperature in the evolution of the Universe at which two vacuua v1, v2 can swap between being true and false. We evaluate the dynamical surface pressure on domain walls between low and high mass vaccua due to the presence of matter and show that the low mass state remains the preferred vacuum of the Universe.

Vacuum Pump System Optimization Saves Energy at a Dairy Farm

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

None

In 1998, S&S Dairy optimized the vacuum pumping system at their dairy farm in Modesto, California. In an effort to reduce energy costs, S&S Dairy evaluated their vacuum pumping system to determine if efficiency gains and energy savings were possible.

7 CFR 319.8-8 - Lint, linters, and waste.

Code of Federal Regulations, 2013 CFR

2013-01-01

... vacuum fumigation by approved methods at any port where approved fumigation facilities are available. (ii... facilities are available, for the required vacuum fumigation. (iii) Such lint, linters, and waste compressed... where approved fumigation facilities are available, there to receive the required vacuum fumigation...

7 CFR 319.8-8 - Lint, linters, and waste.

Code of Federal Regulations, 2014 CFR

2014-01-01

... vacuum fumigation by approved methods at any port where approved fumigation facilities are available. (ii... facilities are available, for the required vacuum fumigation. (iii) Such lint, linters, and waste compressed... where approved fumigation facilities are available, there to receive the required vacuum fumigation...

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

DTIC Science & Technology

2012-10-01

materials to facilitate dissemination of this technique. 15. SUBJECT TERMS Transfemoral amputation, sub-ischial socket, prosthesis , vacuum-assisted...an appropriate mechanical pump to create suitable vacuum for suspension of the prosthesis ...sockets of highly active prosthesis users

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

Vacuum-jacketed transfer line installation technique

NASA Technical Reports Server (NTRS)

Bowers, W. M.

1968-01-01

Rolling-type spacers in the form of steel balls retained in appropriate sleeves affixed at intervals to the exterior of the transfer line facilitate the installation of a vacuum-jacketed line. They act as standoffs to position the transfer line concentrically within the vacuum jacket line.

Active hold-down for heat treating

NASA Technical Reports Server (NTRS)

Collins, E. R., Jr. (Inventor)

1986-01-01

The object of the disclosure is to provide a vacuum hold-down for holding thin sheets to a support surface, which permits the thin sheet to change dimensions as it is held down. The hold-down includes numerous holes in the support surface, through which a vacuum is applied from a vacuum source. The holes are arranged in zones. The vacuum is repeatedly interrupted at only one or a few zones, while it continues to be applied to other zones, to allow the workpiece to creep along that interrupted zone. The vacuum to different zones is interrupted at different times, as by a slowly turning valve number, to allow each zone of the workpiece to creep. A positive pressure may be applied from a pressured air source to a zone when the vacuum is interrupted there, to help lift the corresponding workpiece zone off the surface to aid in creeping. The workpiece may undergo dimensional changes because of heating, cooling, drying, or other procedure.

Controlling superconductivity in La 2-xSr xCuO 4+δ by ozone and vacuum annealing

DOE PAGES

Leng, Xiang; Bozovic, Ivan

2014-11-21

In this study we performed a series of ozone and vacuum annealing experiments on epitaxial La 2-xSr xCuO 4+δ thin films. The transition temperature after each annealing step has been measured by the mutual inductance technique. The relationship between the effective doping and the vacuum annealing time has been studied. Short-time ozone annealing at 470 °C oxidizes an underdoped film all the way to the overdoped regime. The subsequent vacuum annealing at 350 °C to 380 °C slowly brings the sample across the optimal doping point back to the undoped, non-superconducting state. Several ozone and vacuum annealing cycles have beenmore » done on the same sample and the effects were found to be repeatable and reversible Vacuum annealing of ozone-loaded LSCO films is a very controllable process, allowing one to tune the doping level of LSCO in small steps across the superconducting dome, which can be used for fundamental physics studies.« less

Fiber-Reinforced Epoxy Composites and Methods of Making Same Without the Use of Oven or Autoclave

NASA Technical Reports Server (NTRS)

Barnell, Thomas J. (Inventor); Rauscher, Michael D. (Inventor); Stienecker, Rick D. (Inventor); Nickerson, David M. (Inventor); Tong, Tat H. (Inventor)

2016-01-01

Method embodiments for producing a fiber-reinforced epoxy composite comprise providing a mold defining a shape for a composite, applying a fiber reinforcement over the mold, covering the mold and fiber reinforcement thereon in a vacuum enclosure, performing a vacuum on the vacuum enclosure to produce a pressure gradient, insulating at least a portion of the vacuum enclosure with thermal insulation, infusing the fiber reinforcement with a reactive mixture of uncured epoxy resin and curing agent under vacuum conditions, wherein the reactive mixture of uncured epoxy resin and curing agent generates exothermic heat, and producing the fiber-reinforced epoxy composite having a glass transition temperature of at least about 100.degree. C. by curing the fiber reinforcement infused with the reactive mixture of uncured epoxy resin and curing agent by utilizing the exothermically generated heat, wherein the curing is conducted inside the thermally insulated vacuum enclosure without utilization of an external heat source or an external radiation source.

Apollo Experiment Report: Lunar-Sample Processing in the Lunar Receiving Laboratory High-Vacuum Complex

NASA Technical Reports Server (NTRS)

White, D. R.

1976-01-01

A high-vacuum complex composed of an atmospheric decontamination system, sample-processing chambers, storage chambers, and a transfer system was built to process and examine lunar material while maintaining quarantine status. Problems identified, equipment modifications, and procedure changes made for Apollo 11 and 12 sample processing are presented. The sample processing experiences indicate that only a few operating personnel are required to process the sample efficiently, safely, and rapidly in the high-vacuum complex. The high-vacuum complex was designed to handle the many contingencies, both quarantine and scientific, associated with handling an unknown entity such as the lunar sample. Lunar sample handling necessitated a complex system that could not respond rapidly to changing scientific requirements as the characteristics of the lunar sample were better defined. Although the complex successfully handled the processing of Apollo 11 and 12 lunar samples, the scientific requirement for vacuum samples was deleted after the Apollo 12 mission just as the vacuum system was reaching its full potential.

High-Energy Vacuum Birefringence and Dichroism in an Ultrastrong Laser Field

NASA Astrophysics Data System (ADS)

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

2017-12-01

A long-standing prediction of quantum electrodynamics, yet to be experimentally observed, is the interaction between real photons in vacuum. As a consequence of this interaction, the vacuum is expected to become birefringent and dichroic if a strong laser field polarizes its virtual particle-antiparticle dipoles. Here, we derive how a generally polarized probe photon beam is influenced by both vacuum birefringence and dichroism in a strong linearly polarized plane-wave laser field. Furthermore, we consider an experimental scheme to measure these effects in the nonperturbative high-energy regime, where the Euler-Heisenberg approximation breaks down. By employing circularly polarized high-energy probe photons, as opposed to the conventionally considered linearly polarized ones, the feasibility of quantitatively confirming the prediction of nonlinear QED for vacuum birefringence at the 5 σ confidence level on the time scale of a few days is demonstrated for upcoming 10 PW laser systems. Finally, dichroism and anomalous dispersion in vacuum are shown to be accessible at these facilities.

Engineering Matter Interactions Using Squeezed Vacuum

NASA Astrophysics Data System (ADS)

Zeytinoǧlu, Sina; Imamoǧlu, Ataç; Huber, Sebastian

2017-04-01

Virtually all interactions that are relevant for atomic and condensed matter physics are mediated by quantum fluctuations of the electromagnetic field vacuum. Consequently, controlling the vacuum fluctuations can be used to engineer the strength and the range of interactions. Recent experiments have used this premise to demonstrate novel quantum phases or entangling gates by embedding electric dipoles in photonic cavities or wave guides, which modify the electromagnetic fluctuations. Here, we show theoretically that the enhanced fluctuations in the antisqueezed quadrature of a squeezed vacuum state allow for engineering interactions between electric dipoles without the need for a photonic structure. Thus, the strength and range of the interactions can be engineered in a time-dependent way by changing the spatial profile of the squeezed vacuum in a traveling-wave geometry, which also allows the implementation of chiral dissipative interactions. Using experimentally realized squeezing parameters and including realistic losses, we predict single-atom cooperativities C of up to 10 for the squeezed-vacuum-enhanced interactions.

Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes

PubMed Central

Fujimoto, Hiroshi; Suekane, Takashi; Imanishi, Katsuya; Yukiwaki, Satoshi; Wei, Hong; Nagayoshi, Kaori; Yahiro, Masayuki; Adachi, Chihaya

2016-01-01

We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility. PMID:27958304

Compact vacuum tubes with GaAs(Cs,O) photocathodes for studying spin-dependent phenomena

NASA Astrophysics Data System (ADS)

Alperovich, V. L.; Orlov, D. A.; Grishaev, V. G.; Kosolobov, S. N.; Jaroshevich, A. S.; Scheibler, H. E.; Terekhov, A. S.

2009-08-01

Compact proximity focused vacuum tubes with GaAs(Cs,O) photocathodes are used for experimental studying spindependent phenomena. Firstly, spin-dependent emission of optically oriented electrons from p-GaAs(Cs,O) into vacuum in a magnetic field normal to the surface was observed in a nonmagnetic vacuum diode. This phenomenon is explained by the jump in the electron g-factor at the semiconductor-vacuum interface. Due to this jump, the effective electron affinity on the semiconductor surface depends on the mutual direction of optically oriented electron spins and the magnetic field, resulting in the spin-dependent photoemission. It is demonstrated that the observed effect can be used for the determination of spin diffusion length in semiconductors. Secondly, we developed a prototype of a new spin filter, which consists of a vacuum tube with GaAs(Cs,O) photocathode and a nickel-covered venetian blind dynode. Preliminary results on spin-dependent reflection of electrons from the oxidized polycrystal nickel layer are presented.

On thermionic emission and the use of vacuum tubes in the advanced physics laboratory

NASA Astrophysics Data System (ADS)

Angiolillo, Paul J.

2009-12-01

Two methods are outlined for measuring the charge-to-mass ratio e /me of the electron using thermionic emission as exploited in vacuum tube technology. One method employs the notion of the space charge in the vacuum tube diode as described by the Child-Langmuir equation; the other method uses the electron trajectories in vacuum tube pentodes with cylindrical electrodes under conditions of orthogonally related electric and magnetic fields (the Hull magnetron method). The vacuum diode method gave e /me=1.782±0.166×10+11 C/kg (averaged over the vacuum diodes studied), and the Hull magnetron method gave e /me=1.779±0.208×10+11 C/kg (averaged over both pentodes and the anode voltages studied). These methods afford opportunities for students to determine the e /me ratio without using the Bainbridge tube method and to become familiar with phenomena not normally covered in a typical experimental methods curriculum.

The dynamic volume changes of polymerising polymethyl methacrylate bone cement.

PubMed

Muller, Scott D; Green, Sarah M; McCaskie, Andrew W

2002-12-01

The Swedish hip register found an increased risk of early revision of vacuum-mixed cemented total hip replacements. The influence of cement mixing technique on the dynamic volume change in polymerising PMMA is not well understood and may be relevant to this observation. Applying Archimedes' principle, we have investigated the dynamic volume changes in polymerising cement and determined the influence of mixing technique. All specimens showed an overall volume reduction: hand-mixed 3.4% and vacuum-mixed 6.0%. Regression analysis of sectional porosity and volume reduction showed a highly significant relationship. Hand-mixed porous cement showed a transient volume increase before solidification. However, vacuum-mixed cement showed a progressive volume reduction throughout polymerisation. Transient expansion of porous cement occurs at the critical time of micro-interlock formation, possibly improving fixation. Conversely, progressive volume reduction of vacuum-mixed cement throughout the formation of interlock may damage fixation. Stable fixation of vacuum-mixed cement may depend on additional techniques to offset the altered volumetric behaviour of vacuum-mixed cement.

Controlling superconductivity in La 2-xSr xCuO 4+δ by ozone and vacuum annealing

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

Leng, Xiang; Bozovic, Ivan

In this study we performed a series of ozone and vacuum annealing experiments on epitaxial La 2-xSr xCuO 4+δ thin films. The transition temperature after each annealing step has been measured by the mutual inductance technique. The relationship between the effective doping and the vacuum annealing time has been studied. Short-time ozone annealing at 470 °C oxidizes an underdoped film all the way to the overdoped regime. The subsequent vacuum annealing at 350 °C to 380 °C slowly brings the sample across the optimal doping point back to the undoped, non-superconducting state. Several ozone and vacuum annealing cycles have beenmore » done on the same sample and the effects were found to be repeatable and reversible Vacuum annealing of ozone-loaded LSCO films is a very controllable process, allowing one to tune the doping level of LSCO in small steps across the superconducting dome, which can be used for fundamental physics studies.« less

Impact of Vacuum Cooling on Escherichia coli O157:H7 Infiltration into Lettuce Tissue▿

PubMed Central

Li, Haiping; Tajkarimi, Mehrdad; Osburn, Bennie I.

2008-01-01

Vacuum cooling is a common practice in the California leafy green industry. This study addressed the impact of vacuum cooling on the infiltration of Escherichia coli O157:H7 into lettuce as part of the risk assessment responding to the E. coli O157:H7 outbreaks associated with leafy green produce from California. Vacuum cooling significantly increased the infiltration of E. coli O157:H7 into the lettuce tissue (2.65E+06 CFU/g) compared to the nonvacuumed condition (1.98E+05 CFU/g). A stringent surface sterilization and quadruple washing could not eliminate the internalized bacteria from lettuce. It appeared that vacuuming forcibly changed the structure of lettuce tissue such as the stomata, suggesting a possible mechanism of E. coli O157:H7 internalization. Vacuuming also caused a lower reduction rate of E. coli O157:H7 in stored lettuce leaves than that for the nonvacuumed condition. PMID:18344328

Vacuum Radiance-Temperature Standard Facility for Infrared Remote Sensing at NIM

NASA Astrophysics Data System (ADS)

Hao, X. P.; Song, J.; Xu, M.; Sun, J. P.; Gong, L. Y.; Yuan, Z. D.; Lu, X. F.

2018-06-01

As infrared remote sensors are very important parts of Earth observation satellites, they must be calibrated based on the radiance temperature of a blackbody in a vacuum chamber prior to launch. The uncertainty of such temperature is thus an essential component of the sensors' uncertainty. This paper describes the vacuum radiance-temperature standard facility (VRTSF) at the National Institute of Metrology of China, which will serve to calibrate infrared remote sensors on Chinese meteorological satellites. The VRTSF can be used to calibrate vacuum blackbody radiance temperature, including those used to calibrate infrared remote sensors. The components of the VRTSF are described in this paper, including the VMTBB, the LNBB, the FTIR spectrometer, the reduced-background optical system, the vacuum chamber used to calibrate customers' blackbody, the vacuum-pumping system and the liquid-nitrogen-support system. The experimental methods and results are expounded. The uncertainty of the radiance temperature of VMTBB is 0.026 °C at 30 °C over 10 μm.

Impact of vacuum frying on quality of potato crisps and frying oil.

PubMed

Belkova, Beverly; Hradecky, Jaromir; Hurkova, Kamila; Forstova, Veronika; Vaclavik, Lukas; Hajslova, Jana

2018-02-15

This research was focused on a critical assessment of vacuum frying as a technology enabling minimization of acrylamide formation in potato crisps and reducing undesirable chemical changes that occur in frying oil at high temperatures. The potato slices were fried in rapeseed oil under vacuum at 125°C and atmospheric pressure at 165°C. The experiments were performed on two potato varieties, Saturna and Impala. Vacuum frying reduced the formation of acrylamide by 98% and also other Maillard reaction products, specifically alkylpyrazines. Concurrently a lower extent of oxidative changes was observed in the frying oil, while 3-MCPD esters decreased fairly quickly during conventional frying. Sensory characteristics of the vacuum and conventionally fried potato crisps were evaluated by a 23-member panel. The majority of panellists preferred the flavour of 'conventional crisps', while only a few of them appreciated potato-like fresh flavour of 'vacuum crisps' and classified this product as 'tasty'. Copyright © 2017. Published by Elsevier Ltd.

Influence of vacuum chamber impurities on the lifetime of organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Fujimoto, Hiroshi; Suekane, Takashi; Imanishi, Katsuya; Yukiwaki, Satoshi; Wei, Hong; Nagayoshi, Kaori; Yahiro, Masayuki; Adachi, Chihaya

2016-12-01

We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility.

Can Vacuum Assisted Venous Drainage be Achieved using a Roller Pump in an Emergency? A Pilot Study using Neonatal Circuitry

PubMed Central

Hill, S. L.; Holt, D. W.

2007-01-01

Abstract: There has been much advancement in perfusion technology over its 50 years of progression. One of these techniques is vacuum-assisted venous drainage (VAVD). Many perfusionists augment venous drainage using VAVD, typically from a wall vacuum source. This study explores alternates to providing VAVD if the wall vacuum fails. In two porcine laboratories, ∼36 in. of 3/16-in. tubing was connected to a sucker return port and placed into the roller head next to the arterial pump. The vacuum was monitored with a DLP pressure monitoring system (Medtronic). This system was connected to small-bore tubing and attached to a stopcock on top of the reservoir. The vacuum was regulated using another stopcock connected to a non-filtered luer lock port on top of the reservoir or by a segment of 3 × 0.25-in.-diameter tubing attached to the vent port with a c-clamp. Vacuum drainage was achieved, ranging from −18 mmHg to −71 mmHg by manipulating the stopcock or c-clamp. Changes in venous drainage were seen by volume fluctuations in the venous reservoir. The vacuum was adjusted to account for dramatic changes. Augmented venous drainage using a roller pump can be achieved successfully during cardiopulmonary bypass (CPB). This method of active drainage can be used in lieu of wall suction or during times of emergency if wall suction fails. PMID:18293812

Preservation Effect of Two-Stage Cinnamon Bark (Cinnamomum Burmanii) Oleoresin Microcapsules On Vacuum-Packed Ground Beef During Refrigerated Storage

NASA Astrophysics Data System (ADS)

Irfiana, D.; Utami, R.; Khasanah, L. U.; Manuhara, G. J.

2017-04-01

The purpose of this study was to determine the effect of two stage cinnamon bark oleoresin microcapsules (0%, 0.5% and 1%) on the TPC (Total Plate Count), TBA (thiobarbituric acid), pH, and RGB color (Red, Green, and Blue) of vacuum-packed ground beef during refrigerated storage (at 0, 4, 8, 12, and 16 days). This study showed that the addition of two stage cinnamon bark oleoresin microcapsules affected the quality of vacuum-packed ground beef during 16 days of refrigerated storage. The results showed that the TPC value of the vacuum-packed ground beef sample with the addition 0.5% and 1% microcapsules was lower than the value of control sample. The TPC value of the control sample, sample with additional 0.5% and 1% microcapsules were 5.94; 5.46; and 5.16 log CFU/g respectively. The TBA value of vacuum-packed ground beef were 0.055; 0.041; and 0.044 mg malonaldehyde/kg, resepectively on the 16th day of storage. The addition of two-stage cinnamon bark oleoresin microcapsules could inhibit the growth of microbia and decrease the oxidation process of vacuum-packed ground beef. Moreover, the change of vacuum-packed ground beef pH and RGB color with the addition 0.5% and 1% microcapsules were less than those of the control sample. The addition of 1% microcapsules showed the best effect in preserving the vacuum-packed ground beef.

[Assessment of vacuum-assisted vaginal delivery in a frank breech presentation].

PubMed

Bleu, G; Deruelle, P; Demetz, J; Michel, S; Dufour, P; Depret, S; Subtil, D

2015-02-01

After verification of the eligibility criteria and with an obstetrician familiar with the specific maneuvers likely to be needed, vaginal delivery of breech presentations is possible. If problems arise during the active pushing phase of labor, vacuum extraction has been described in the literature for this uncommon condition with limited series. The aim of this study is to assess retrospectively vacuum extraction in frank breech presentation in our center. This retrospective study of trials of vaginal delivery of fetuses in breech presentation at term compares cases according to whether they did or did not use a vacuum extraction. During a two-year period, 83 patients, whom had trials of vaginal delivery in breech presentations, reached the active pushing/bearing down stage after complete cervical dilatation. Vacuum assistance was applied in six of these (7.2 %). The failure rate for vaginal delivery was significantly higher in the group with compared to without vacuum extraction (33.3 % versus 6.5 %, P<0.05). Moreover, the mean pH at birth was significantly lower in the group with vacuum extraction (7.12±0.11 versus 7.20±0.08, P<0.05), and these infants more frequently had deep cutaneous injuries (66.7 % versus 26.0 %, P<0.05). In fetuses in breech presentation, when vaginal delivery failed, it seems to be safer for the fetuses to perform caesarean section rather than attempt vacuum extraction. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Comparison of occlusion break responses and vacuum rise times of phacoemulsification systems.

PubMed

Sharif-Kashani, Pooria; Fanney, Douglas; Injev, Val

2014-07-30

Occlusion break surge during phacoemulsification cataract surgery can lead to potential surgical complications. The purpose of this study was to quantify occlusion break surge and vacuum rise time of current phacoemulsification systems used in cataract surgery. Occlusion break surge at vacuum pressures between 200 and 600 mmHg was assessed with the Infiniti® Vision System, the WhiteStar Signature® Phacoemulsification System, and the Centurion® Vision System using gravity-fed fluidics. Centurion Active FluidicsTM were also tested at multiple intraoperative pressure target settings. Vacuum rise time was evaluated for Infiniti, WhiteStar Signature, Centurion, and Stellaris® Vision Enhancement systems. Rise time to vacuum limits of 400 and 600 mmHg was assessed at flow rates of 30 and 60 cc/minute. Occlusion break surge was analyzed by 2-way analysis of variance. The Centurion system exhibited substantially less occlusion break surge than the other systems tested. Surge area with Centurion Active Fluidics was similar to gravity fluidics at an equivalent bottle height. At all Centurion Active Fluidics intraoperative pressure target settings tested, surge was smaller than with Infiniti and WhiteStar Signature. Infiniti had the fastest vacuum rise time and Stellaris had the slowest. No system tested reached the 600-mmHg vacuum limit. In this laboratory study, Centurion had the least occlusion break surge and similar vacuum rise times compared with the other systems tested. Reducing occlusion break surge may increase safety of phacoemulsification cataract surgery.

Comparison of occlusion break responses and vacuum rise times of phacoemulsification systems

PubMed Central

2014-01-01

Background Occlusion break surge during phacoemulsification cataract surgery can lead to potential surgical complications. The purpose of this study was to quantify occlusion break surge and vacuum rise time of current phacoemulsification systems used in cataract surgery. Methods Occlusion break surge at vacuum pressures between 200 and 600 mmHg was assessed with the Infiniti® Vision System, the WhiteStar Signature® Phacoemulsification System, and the Centurion® Vision System using gravity-fed fluidics. Centurion Active FluidicsTM were also tested at multiple intraoperative pressure target settings. Vacuum rise time was evaluated for Infiniti, WhiteStar Signature, Centurion, and Stellaris® Vision Enhancement systems. Rise time to vacuum limits of 400 and 600 mmHg was assessed at flow rates of 30 and 60 cc/minute. Occlusion break surge was analyzed by 2-way analysis of variance. Results The Centurion system exhibited substantially less occlusion break surge than the other systems tested. Surge area with Centurion Active Fluidics was similar to gravity fluidics at an equivalent bottle height. At all Centurion Active Fluidics intraoperative pressure target settings tested, surge was smaller than with Infiniti and WhiteStar Signature. Infiniti had the fastest vacuum rise time and Stellaris had the slowest. No system tested reached the 600-mmHg vacuum limit. Conclusions In this laboratory study, Centurion had the least occlusion break surge and similar vacuum rise times compared with the other systems tested. Reducing occlusion break surge may increase safety of phacoemulsification cataract surgery. PMID:25074069

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

33 CFR 159.111 - Pressure and vacuum pulse test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Pressure and vacuum pulse test... (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.111 Pressure and vacuum pulse test. Liquid retention components of the device with manufacturer specified venting...

Copyboard Quickly Makes Clean Printing Plates

NASA Technical Reports Server (NTRS)

Balandis, W. D.

1985-01-01

Vacuum-chuck eliminates glass and sponge artwork support. Vacuum copyboard allows camera-ready original slid on top plate for proper positioning, then holds securely for photography. Bleed valve allows vacuum in copyboard box adjusted for small or large originals. With new copyboard, time-consuming and costly procedures unnecessary.

13. VIEW OF VACUUM CHAMBER AND WELDING EQUIPMENT IN MODULE ...

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

13. VIEW OF VACUUM CHAMBER AND WELDING EQUIPMENT IN MODULE E. PARTS WERE WELDED UNDER A VACUUM TO PREVENT CORROSION. (11/6/73) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

Working in a Vacuum

ERIC Educational Resources Information Center

Rathey, Allen

2005-01-01

In this article, the author discusses several myths about vacuum cleaners and offers tips on evaluating and purchasing this essential maintenance tool. These myths are: (1) Amps mean performance; (2) Everyone needs high-efficiency particulate air (HEPA): (3) Picking up a "bowling ball" shows cleaning power; (4) All vacuum bags are the same; (5)…

A portable vacuum for collecting arthropods from drop cloths.

Treesearch

H.G. Paul; R.R. Mason

1985-01-01

A hand-held vacuum modified for collecting insects and spiders in the field is described. The vacuum with battery is mounted on a lightweight pack-frame and is portable and versatile. It is especially useful for collecting arthropods that are dislodged from foliage samples and drop onto cloths.

Purifying Aluminum by Vacuum Distillation

NASA Technical Reports Server (NTRS)

Du Fresne, E. R.

1985-01-01

Proposed method for purifying aluminum employs one-step vacuum distillation. Raw material for process impure aluminum produced in electrolysis of aluminum ore. Impure metal melted in vacuum. Since aluminum has much higher vapor pressure than other constituents, boils off and condenses on nearby cold surfaces in proportions much greater than those of other constituents.

High Stability Metal-Protein Interactions Evaluated by Microcalorimetry

DTIC Science & Technology

2016-04-29

microprocessor -controlled internal vacuum pump runs for a 90 second period, then it evaluates the vacuum pressure attained, and if that value meets spec...and the other with the software. There is a place in the wash module program where the ITC’s microprocessor - controlled internal vacuum pump runs for

Vacuum Virtues

ERIC Educational Resources Information Center

Rathey, Allen

2007-01-01

Upright vacuums, like cars, vary in quality, features and performance. Like automobiles, some uprights are reliable, others may be problematic, and some become a problem as a result of neglect or improper use. So, how do education institutions make an informed choice and, having done so, ensure that an upright vacuum goes the distance? In this…

14. VIEW OF VACUUM COATING CHAMBER. THE SYSTEM USED TITANIUM ...

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

14. VIEW OF VACUUM COATING CHAMBER. THE SYSTEM USED TITANIUM VAPORS TO DEPOSIT TITANIUM COATING ONTO URANIUM PARTS UNDER A VACUUM. (1/11/83) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

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

DTIC Science & Technology

2013-10-01

15. SUBJECT TERMS Transfemoral amputation, sub-ischial socket, prosthesis , vacuum-assisted suspension 16. SECURITY CLASSIFICATION OF: 17...vacuum for suspension of the prosthesis ...14 Task 6 Determine range of volumes to be evacuated from transfemoral sockets of highly active prosthesis users

7 CFR 58.230 - Heavy duty vacuum cleaners.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Heavy duty vacuum cleaners. 58.230 Section 58.230 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....230 Heavy duty vacuum cleaners. Each plant handling dry milk products shall be equipped with a heavy...

40 CFR 63.1063 - Floating roof requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... opening except those for automatic bleeder vents (vacuum breaker vents) and rim space vents shall have its... vents (vacuum breaker vents), rim space vents, leg sleeves, and deck drains shall be equipped with a... automatic bleeder vent (vacuum breaker vent) and rim space vent shall be equipped with a gasketed lid...

40 CFR 63.1063 - Floating roof requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... opening except those for automatic bleeder vents (vacuum breaker vents) and rim space vents shall have its... vents (vacuum breaker vents), rim space vents, leg sleeves, and deck drains shall be equipped with a... automatic bleeder vent (vacuum breaker vent) and rim space vent shall be equipped with a gasketed lid...

40 CFR 63.1063 - Floating roof requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... opening except those for automatic bleeder vents (vacuum breaker vents) and rim space vents shall have its... vents (vacuum breaker vents), rim space vents, leg sleeves, and deck drains shall be equipped with a... automatic bleeder vent (vacuum breaker vent) and rim space vent shall be equipped with a gasketed lid...

40 CFR 63.1063 - Floating roof requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... opening except those for automatic bleeder vents (vacuum breaker vents) and rim space vents shall have its... vents (vacuum breaker vents), rim space vents, leg sleeves, and deck drains shall be equipped with a... automatic bleeder vent (vacuum breaker vent) and rim space vent shall be equipped with a gasketed lid...

Vacuum coupling of rotating superconducting rotor

DOEpatents

Shoykhet, Boris A.; Zhang, Burt Xudong; Driscoll, David Infante

2003-12-02

A rotating coupling allows a vacuum chamber in the rotor of a superconducting electric motor to be continually pumped out. The coupling consists of at least two concentric portions, one of which is allowed to rotate and the other of which is stationary. The coupling is located on the non-drive end of the rotor and is connected to a coolant supply and a vacuum pump. The coupling is smaller in diameter than the shaft of the rotor so that the shaft can be increased in diameter without having to increase the size of the vacuum seal.

The cosmic vacuum and the rotation of galaxies

NASA Astrophysics Data System (ADS)

Chechin, L. M.

2010-08-01

The rotational effect of the cosmic vacuum is investigated. The induced rotation of elliptical galaxies due to the anti-gravity of the vacuum is found to be 10-21 s-1 for real elliptical galaxies. The effect of the vacuum rotation of the entire Universe is discussed, and can be described by the invariant ω ν = ω 0 ˜ sqrt {Gρ v} . The corresponding numerical angular velocity of the Universe is 10-19 s-1, in good agreement with modern data on the temperature fluctuations of the cosmic background radiation.

Convenient mounting method for electrical measurements of thin samples

NASA Technical Reports Server (NTRS)

Matus, L. G.; Summers, R. L.

1986-01-01

A method for mounting thin samples for electrical measurements is described. The technique is based on a vacuum chuck concept in which the vacuum chuck simultaneously holds the sample and established electrical contact. The mounting plate is composed of a glass-ceramic insulating material and the surfaces of the plate and vacuum chuck are polished. The operation of the vacuum chuck is examined. The contacts on the sample and mounting plate, which are sputter-deposited through metal masks, are analyzed. The mounting method was utilized for van der Pauw measurements.

Single Qubit Manipulation in a Microfabricated Surface Electrode Ion Trap (Open Access, Publisher’s Version)

DTIC Science & Technology

2013-09-13

electric fields due to charge build up on the vacuum viewport. For some experiments a non-evaporable getter (NEG) pump is placed 3.3mm away from the...trap, between the trap and the solid aluminum ground shield, to reduce the vacuum pressure close to the ion. The vacuum chamber is constantly pumped by...an ion pump , a titanium sublimation pump and the NEG pump . The pressure of the vacuum system was below what is measurable by the ion gage used (ə.9

MoS2-Filled PEEK Composite as a Self-Lubricating Material for Aerospace Applications

NASA Technical Reports Server (NTRS)

Theiler, Geraldine; Gradt, Thomas

2010-01-01

At BAM, several projects were conducted in the past years dealing with the tribological properties of friction couples at cryogenic temperature and in vacuum environment. Promising candidates for vacuum application are MoS2-filled PEEK/PTFE composites, which showed a friction coefficient as low as 0.03 in high vacuum. To complete the tribological profile of these composites, further tests were performed in ultra-high vacuum (UHV) at room temperature. In this paper, friction and stick slip behavior, as well as outgassing characteristics during the test are presented.

Vacuum Energy Induced by AN Impenetrable Flux Tube of Finite Radius

NASA Astrophysics Data System (ADS)

Gorkavenko, V. M.; Sitenko, Yu. A.; Stepanov, O. B.

2011-06-01

We consider the effect of the magnetic field background in the form of a tube of the finite transverse size on the vacuum of the quantized charged massive scalar field which is subject to the Dirichlet boundary condition at the edge of the tube. The vacuum energy is induced, being periodic in the value of the magnetic flux enclosed in the tube. The dependence of the vacuum energy density on the distance from the tube and on the coupling to the space-time curvature scalar is comprehensively analyzed.

Vacuum Energy Induced by AN Impenetrable Flux Tube of Finite Radius

NASA Astrophysics Data System (ADS)

Gorkavenko, V. M.; Sitenko, Yu. A.; Stepanov, O. B.

We consider the effect of the magnetic field background in the form of a tube of the finite transverse size on the vacuum of the quantized charged massive scalar field which is subject to the Dirichlet boundary condition at the edge of the tube. The vacuum energy is induced, being periodic in the value of the magnetic flux enclosed in the tube. The dependence of the vacuum energy density on the distance from the tube and on the coupling to the space-time curvature scalar is comprehensively analyzed.

Cosmological implications of Higgs near-criticality

NASA Astrophysics Data System (ADS)

Espinosa, J. R.

2018-01-01

The Standard Model electroweak (EW) vacuum, in the absence of new physics below the Planck scale, lies very close to the boundary between stability and metastability, with the last option being the most probable. Several cosmological implications of this so-called `near-criticality' are discussed. In the metastable vacuum case, the main challenges that the survival of the EW vacuum faces during the evolution of the Universe are analysed. In the stable vacuum case, the possibility of implementing Higgs inflation is critically examined. This article is part of the Theo Murphy meeting issue `Higgs cosmology'.

Infrared detector Dewars - Increased LN2 hold time and vacuum jacket life spans

NASA Technical Reports Server (NTRS)

Jennings, D. E.; Boyd, W. J.; Blass, W. E.

1976-01-01

IR detector Dewars commonly suffer from shorter than desired LN2 hold times and insulation jacket vacuum corruption over relatively short time periods. In an attempt to solve this problem for a 9144 detector Dewar, small 1 liter/s appendage ion pumps were selected for continuous pumping of the vacuum jackets. This procedure extended LN2 hold times from 20 to 60 h and virtually eliminated vacuum jacket corruption. Thus the detector systems are usable continuously over periods of 6 months or more.

Conditioning of the vacuum system of the TPS storage ring without baking in situ

NASA Astrophysics Data System (ADS)

Chan, C. K.; Chang, C. C.; Shueh, C.; Yang, I. C.; Wu, L. H.; Chen, B. Y.; Cheng, C. M.; Huang, Y. T.; Chuang, J. Y.; Cheng, Y. T.; Hsiao, Y. M.; Sheng, Albert

2017-04-01

To shorten the machine downtime, a maintenance procedure without baking in situ has been developed and applied to maintain and to upgrade the vacuum system of the TPS storage ring. The data of photon-stimulated desorption (PSD) reveal no obvious discrepancy between baking and not baking the vacuum system in situ. A beam-conditioning dose of extent only 11.8 A h is required to recover quickly the dynamic pressure of an unbaked vacuum system to its pre-intervention value according to the TPS maintenance experience.

Breakdown Conditioning Chacteristics of Precision-Surface-Treatment-Electrode in Vacuum

NASA Astrophysics Data System (ADS)

Kato, Kastumi; Fukuoka, Yuji; Inagawa, Yukihiko; Saitoh, Hitoshi; Sakaki, Masayuki; Okubo, Hitoshi

Breakdown (BD) characteristics in vacuum are strongly dependent on the electrode surface condition, like the surface roughness etc. Therefore, in order to develop a high voltage vacuum circuit breaker, it is important to optimize the surface treatment process. This paper discusses about the effect of precision-surface-treatment of the electrode on breakdown conditioning characteristics under non-uniform electric field in vacuum. Experimental results reveal that the electrode surface treatment affects the conditioning process, especially the BD voltage and the BD field strength at the initial stage of the conditioning.

Casimir switch: steering optical transparency with vacuum forces.

PubMed

Liu, Xi-Fang; Li, Yong; Jing, H

2016-06-03

The Casimir force, originating from vacuum zero-point energy, is one of the most intriguing purely quantum effects. It has attracted renewed interests in current field of nanomechanics, due to the rapid size decrease of on-chip devices. Here we study the optomechanically-induced transparency (OMIT) with a tunable Casimir force. We find that the optical output rate can be significantly altered by the vacuum force, even terminated and then restored, indicating a highly-controlled optical switch. Our result addresses the possibility of designing exotic optical nano-devices by harnessing the power of vacuum.

Dynamical emergence of the Universe into the false vacuum

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

Rafelski, Johann; Birrell, Jeremiah, E-mail: rafelski@physics.arizona.edu, E-mail: jbirrell@email.arizona.edu

We study how the hot Universe evolves and acquires the prevailing vacuum state, demonstrating that in specific conditions which are believed to apply, the Universe becomes frozen into the state with the smallest value of Higgs vacuum field v=( h), even if this is not the state of lowest energy. This supports the false vacuum dark energy Λ-model. Under several likely hypotheses we determine the temperature in the evolution of the Universe at which two vacuua v{sub 1}, v{sub 2} can swap between being true and false. We evaluate the dynamical surface pressure on domain walls between low and high mass vaccuamore » due to the presence of matter and show that the low mass state remains the preferred vacuum of the Universe.« less

Extreme-UV lithography vacuum chamber zone seal

DOEpatents

Haney, Steven J.; Herron, Donald Joe; Klebanoff, Leonard E.; Replogle, William C.

2001-01-01

Control of particle contamination on the reticle and carbon contamination of optical surfaces in photolithography systems can be achieved by the establishment of multiple pressure zones in the photolithography systems. The different zones will enclose the reticle, projection optics, wafer, and other components of system. The system includes a vacuum apparatus that includes: a housing defining a vacuum chamber; one or more metrology trays situated within the vacuum chamber each of which is supported by at least one support member, wherein the tray separates the vacuum chamber into a various compartments that are maintained at different pressures; and conductance seal devices for adjoining the perimeter of each tray to an inner surface of the housing wherein the tray is decoupled from vibrations emanating from the inner surface of the housing.

Extreme-UV lithography vacuum chamber zone seal

DOEpatents

Haney, Steven J.; Herron, Donald Joe; Klebanoff, Leonard E.; Replogle, William C.

2003-04-08

Control of particle contamination on the reticle and carbon contamination of optical surfaces in photolithography systems can be achieved by the establishment of multiple pressure zones in the photolithography systems. The different zones will enclose the reticle, projection optics, wafer, and other components of system. The system includes a vacuum apparatus that includes: a housing defining a vacuum chamber; one or more metrology trays situated within the vacuum chamber each of which is supported by at least one support member, wherein the tray separates the vacuum chamber into a various compartments that are maintained at different pressures; and conductance seal devices for adjoining the perimeter of each tray to an inner surface of the housing wherein the tray is decoupled from vibrations emanating from the inner surface of the housing.

Extreme-UV lithography vacuum chamber zone seal

DOEpatents

Haney, Steven J.; Herron, Donald Joe; Klebanoff, Leonard E.; Replogle, William C.

2003-04-15

Control of particle contamination on the reticle and carbon contamination of optical surfaces in photolithography systems can be achieved by the establishment of multiple pressure zones in the photolithography systems. The different zones will enclose the reticle, projection optics, wafer, and other components of system. The system includes a vacuum apparatus that includes: a housing defining a vacuum chamber; one or more metrology trays situated within the vacuum chamber each of which is supported by at least one support member, wherein the tray separates the vacuum chamber into a various compartments that are maintained at different pressures; and conductance seal devices for adjoining the perimeter of each tray to an inner surface of the housing wherein the tray is decoupled from vibrations emanating from the inner surface of the housing.

An assessment of the hardness of miniature vacuum tubes to high-voltage transients

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

Orvis, W.J.

1990-03-01

Miniature vacuum tubes are vacuum switching and control devices fabricated on a silicon wafer, using the same technology as is used to make integrated circuits. They operate in much the same manner as conventional vacuum tubes, but with two important differences: they are micron sized devices, and they employ field emission instead of thermionic emission as the electron source. As these devices have a vacuum as their active region, they will be extremely hard to nuclear radiation and relatively insensitive to temperature effects, they are also expected to be extremely fast devices. We have estimated here that their hardness tomore » high-voltage transients will be at least as good as existing semiconductor devices and possibly better. 5 figs.« less

Negative vacuum energy densities and the causal diamond measure

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

Salem, Michael P.

2009-07-15

Arguably a major success of the landscape picture is the prediction of a small, nonzero vacuum energy density. The details of this prediction depend in part on how the diverging spacetime volume of the multiverse is regulated, a question that remains unresolved. One proposal, the causal diamond measure, has demonstrated many phenomenological successes, including predicting a distribution of positive vacuum energy densities in good agreement with observation. In the string landscape, however, the vacuum energy density is expected to take positive and negative values. We find the causal diamond measure gives a poor fit to observation in such a landscapemore » - in particular, 99.6% of observers in galaxies seemingly just like ours measure a vacuum energy density smaller than we do, most of them measuring it to be negative.« less

MASS SEPARATORS

DOEpatents

Oppenheimer, F.; Bell, J.W.

1959-02-17

An improvement in the mounting arrangement for the ion source within the vacuum tank of a calutron is presented. The entire source is supported by the vacuum envelope through the medium of a bracket secured to a removable face plate. The bracket forms a supporting platform that is generally transverse to the magnetic field. The ion generator is mounted on a pedestal-type insulator supported on the bracket, and the hot leads are brought into the vacuum envelope through a tubular elbow connected to the vacuum envelope, having the axis of its outer opening aligned with the magnetic field at which point a bushing-type insulator is employed. With this arrangement thc ion source is maintained at a positive potential with respect to the vacuum tank and the problem of electron bombardment of the insulator is considerably reduced.

Study on the Removal of Gases in RH Refining Progress through Experiments Using Vacuum Induction Furnace

NASA Astrophysics Data System (ADS)

Niu, Deliang; Liu, Qingcai; Wang, Zhu; Ren, Shan; Lan, Yuanpei; Xu, Minren

Removal of gas is the major function of RH degasser. To optimize the RH refining craft in Chongqing Iron and Steel Co. Ltd, the degassing effect of RH degasser at different degrees of vacuum was investigated using a vacuum induction furnace. In addition, the effect of processing time on the gas content dissolved in molten steel was also studied. The results showed that degree of vacuum was one of the important factors that determined the degassing efficiency in RH refining process. High vacuum degree is helpful in the removal of gas, especially in the removal of [H] dissolved in molten steel. The processing time could be reduced from 25-30 min to 15 minutes and gas content could also meet the demand of RH refining.

High vacuum measurements and calibrations, molecular flow fluid transient effects

DOE PAGES

Leishear, Robert A.; Gavalas, Nickolas A.

2015-04-29

High vacuum pressure measurements and calibrations below 1 × 10 -8 Torr are problematic. Specifically, measurement accuracies change drastically for vacuum gauges when pressures are suddenly lowered in vacuum systems. How can gauges perform like this? A brief system description is first required to answer this question. Calibrations were performed using a vacuum calibration chamber with attached vacuum gauges. To control chamber pressures, vacuum pumps decreased the chamber pressure while nitrogen tanks increased the chamber pressure. By balancing these opposing pressures, equilibrium in the chamber was maintained at selected set point pressures to perform calibrations. When pressures were suddenly decreasedmore » during set point adjustments, a sudden rush of gas from the chamber also caused a surge of gas from the gauges to decrease the pressures in those gauges. Gauge pressures did not return to equilibrium as fast as chamber pressures due to the sparse distribution of gas molecules in the system. This disparity in the rate of pressure changes caused the pressures in different gauges to be different than expected. This discovery was experimentally proven to show that different gauge designs return to equilibrium at different rates, and that gauge accuracies vary for different gauge designs due to fluid transients in molecular flow.« less

Cryogenic Insulation System for Soft Vacuum

NASA Technical Reports Server (NTRS)

Augustynowicz, S. D.; Fesmire, J. E.

1999-01-01

The development of a cryogenic insulation system for operation under soft vacuum is presented in this paper. Conventional insulation materials for cryogenic applications can be divided into three levels of thermal performance, in terms of apparent thermal conductivity [k-value in milliwatt per meter-kelvin (mW/m-K)]. System k-values below 0.1 can be achieved for multilayer insulation operating at a vacuum level below 1 x 10(exp -4) torr. For fiberglass or powder operating below 1 x 10(exp -3) torr, k-values of about 2 are obtained. For foam and other materials at ambient pressure, k-values around 30 are typical. New industry and aerospace applications require a versatile, robust, low-cost thermal insulation with performance in the intermediate range. The target for the new composite insulation system is a k-value below 4.8 mW/m-K (R-30) at a soft vacuum level (from 1 to 10 torr) and boundary temperatures of approximately 77 and 293 kelvin (K). Many combinations of radiation shields, spacers, and composite materials were tested from high vacuum to ambient pressure using cryostat boiloff methods. Significant improvement over conventional systems in the soft vacuum range was demonstrated. The new layered composite insulation system was also shown to provide key benefits for high vacuum applications as well.

Long-life micro vacuum chamber for a micromachined cryogenic cooler

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

Cao, Haishan, E-mail: H.Cao@utwente.nl, E-mail: HaishanCao@gmail.com; Vermeer, Cristian H.; Vanapalli, Srinivas

2015-11-15

Micromachined cryogenic coolers can be used for cooling small electronic devices to improve their performance. However, for reaching cryogenic temperatures, they require a very good thermal insulation from the warm environment. This is established by a vacuum space that for adequate insulation has to be maintained at a pressure of 0.01 Pa or lower. In this paper, the challenge of maintaining a vacuum chamber with a volume of 3.6 × 10{sup −5} m{sup 3} and an inner wall area of 8.1 × 10{sup −3} m{sup 2} at a pressure no higher than 0.01 Pa for five years is theoretically analyzed. The possiblemore » sources of gas, the mechanisms by which these gases enter the vacuum space and their effects on the pressure in the vacuum chamber are discussed. In a long-duration experiment with four stainless steel chambers of the above dimensions and equipped with a chemical getter, the vacuum pressures were monitored for a period of two years. In that period, the measured pressure increase stayed within 0.01 Pa. This study can be used to guide the design of long-lifetime micro vacuum chambers that operate without continuous mechanical pumping.« less

Fetal macrosomia as a risk factor for shoulder dystocia during vacuum extraction.

PubMed

Herzberg, Shmuel; Kabiri, Doron; Mordechai, Tzlil; Haj Yahya, Rani; Chill, Henry; Levitt, Lorinne; Amsalem, Hagai; Ezra, Yossef

2017-08-01

Vacuum extraction of a macrosomic fetus is considered a risk factor for shoulder dystocia (SD). We evaluated maternal and fetal outcomes following vacuum extraction of macrosomic infants. A retrospective cohort study conducted in two large teaching hospitals. All deliveries of macrosomic infants by vacuum extraction and vaginal delivery were compared. The primary outcome measure was SD. Secondary outcome measures were severe perineal lacerations and postpartum hemorrhage. For statistical analysis, we used McNemar's test and χ 2 or Fisher's exact tests. Odds ratios were analyzed via a logistic regression model. From 2003 to 2013, there were 6019 (5.45%) deliveries of macrosomic fetuses, and 230 (0.21%) were delivered by vacuum extraction. There were 23 (10%) and seven (3.04%) cases of SD in the study and control groups, respectively. The risk of SD was significantly higher in the study group (p > 0.05). We found a significant association between SD and vacuum delivery [p = 0.003; OR = 3.54 (95% CI: 1.49-8.42)]. The composite adverse neonatal outcome rate was 6.5% (15/230) and 1.7% (4/230) in the study and control groups, respectively (p = 0.009). Vacuum extraction of a macrosomic infant is a risk factor for shoulder dystocia but not for postpartum hemorrhage or severe vaginal tears.

Comparative Evaluation of Vacuum-based Surface Sampling ...

EPA Pesticide Factsheets

Journal Article Following a biological contamination incident, collection of surface samples is necessary to determine the extent and level of contamination, and to deem an area safe for reentry upon decontamination. Current sampling strategies targeting Bacillus anthracis spores prescribe vacuum-based methods for rough and/or porous surfaces. In this study, four commonly-used B. anthracis spore sampling devices (vacuum socks, 37 mm 0.8 µm MCE filter cassettes, 37 mm 0.3 µm PTFE filter cassettes, and 3MTM forensic filters) were comparatively evaluated for their ability to recover surface-associated spores. The vacuum sock device was evaluated at two sampling speeds (slow and fast), resulting in five total methods evaluated. Aerosolized spores (~105 cm-2) of a surrogate Bacillus species (Bacillus atrophaeus) were allowed to settle onto three material types (concrete, carpet, and upholstery). Ten replicate samples were collected using each vacuum method, from each of the three material types. In addition, stainless steel (i.e., nonporous) surfaces inoculated simultaneously were sampled with pre-moistened wipes. Recoveries from wipes of steel surfaces were utilized to verify the inoculum, and to normalize vacuum-based recoveries across trials. Recovery (CFU cm-2) and relative recovery (vacuum recovery/wipe recovery) were determined for each method and material type. Relative recoveries were compared by one-way and three-way ANOVA. Data analysis by one-

Vacuum-driven power-free microfluidics utilizing the gas solubility or permeability of polydimethylsiloxane (PDMS).

PubMed

Xu, Linfeng; Lee, Hun; Jetta, Deekshitha; Oh, Kwang W

2015-10-21

Suitable pumping methods for flow control remain a major technical hurdle in the path of biomedical microfluidic systems for point-of-care (POC) diagnostics. A vacuum-driven power-free micropumping method provides a promising solution to such a challenge. In this review, we focus on vacuum-driven power-free microfluidics based on the gas solubility or permeability of polydimethylsiloxane (PDMS); degassed PDMS can restore air inside itself due to its high gas solubility or gas permeable nature. PDMS allows the transfer of air into a vacuum through it due to its high gas permeability. Therefore, it is possible to store or transfer air into or through the gas soluble or permeable PDMS in order to withdraw liquids into the embedded dead-end microfluidic channels. This article provides a comprehensive look at the physics of the gas solubility and permeability of PDMS, a systematic review of different types of vacuum-driven power-free microfluidics, and guidelines for designing solubility-based or permeability-based PDMS devices, alongside existing applications. Advanced topics and the outlook in using micropumping that utilizes the gas solubility or permeability of PDMS will be also discussed. We strongly recommend that microfluidics and lab-on-chip (LOC) communities harness vacuum energy to develop smart vacuum-driven microfluidic systems.

Effect of drying methods with the application of vacuum microwaves on the bioactive compounds, color, and antioxidant activity of strawberry fruits.

PubMed

Wojdyło, Aneta; Figiel, Adam; Oszmiański, Jan

2009-02-25

The objective of this study was to evaluate the application of vacuum-microwave drying (240, 360, and 480 W) in the production process of dehydrated strawberry and to compare and contrast the quality of these dehydrated strawberries in terms of their polyphenol compounds, concentration of some heat liable components, and color to that of freeze-dried, convective, and vacuum-dried strawberry. Thus, the effect of vacuum-microwave drying and other drying methods on the antioxidant activity of berries was evaluated. Whole fresh and dried fruits were assessed for phenolics (anthocyanins, flavanols, hydroxycinnamic acids, and flavonols), ascorbic acid, and antioxidant activity (all parameters were calculated on a dry matter basis). Analysis of data shows that ellagic acid and flavanol changes were affected by drying techniques and cultivar. Drying destroyed anthocyanins, flavanols, and ascorbic acid, and there was a significant decrease in antioxidant activity. The most striking result was that conventional and vacuum drying decreased antioxidant activity in both cultivars, whereas contradictory results were found for vacuum-microwave processed strawberry. This study has demonstrated that vacuum-microwave drying, especially at 240 W, can produce high-quality products, with the additional advantage of reduced processing times, compared to other processes such as freeze-drying.

Vacuum-isolation vessel and method for measurement of thermal noise in microphones

NASA Technical Reports Server (NTRS)

Zuckerwar, Allan J. (Inventor); Ngo, Kim Chi T. (Inventor)

1992-01-01

The vacuum isolation vessel and method in accordance with the present invention are used to accurately measure thermal noise in microphones. The apparatus and method could be used in a microphone calibration facility or any facility used for testing microphones. Thermal noise is measured to determine the minimum detectable sound pressure by the microphone. Conventional isolation apparatus and methods have been unable to provide an acoustically quiet and substantially vibration free environment for accurately measuring thermal noise. In the present invention, an isolation vessel assembly comprises a vacuum sealed outer vessel, a vacuum sealed inner vessel, and an interior suspension assembly coupled between the outer and inner vessels for suspending the inner vessel within the outer vessel. A noise measurement system records thermal noise data from the isolation vessel assembly. A vacuum system creates a vacuum between an internal surface of the outer vessel and an external surface of the inner vessel. The present invention thus provides an acoustically quiet environment due to the vacuum created between the inner and outer vessels and a substantially vibration free environment due to the suspension assembly suspending the inner vessel within the outer vessel. The thermal noise in the microphone, effectively isolated according to the invention, can be accurately measured.

System for Continuous Deaeration of Hydraulic Oil

NASA Technical Reports Server (NTRS)

Anderson, Christopher W.

2006-01-01

A system for continuous, rapid deaeration of hydraulic oil has been built to replace a prior system that effected deaeration more slowly in a cyclic pressure/ vacuum process. Such systems are needed because (1) hydraulic oil has an affinity for air, typically containing between 10 and 15 volume percent of air and (2) in the original application for which these systems were built, there is a requirement to keep the proportion of dissolved air below 1 volume percent because a greater proportion can lead to pump cavitation and excessive softness in hydraulic-actuator force-versus-displacement characteristics. In addition to overcoming several deficiencies of the prior deaeration system, the present system removes water from the oil. The system (see figure) includes a pump that continuously circulates oil at a rate of 10 gal/min (38 L/min) between an 80-gal (303-L) airless reservoir and a tank containing a vacuum. When the circulation pump is started, oil is pumped, at a pressure of 120 psi (827 kPa), through a venturi tube below the tank with a connection to a stand-pipe in the tank. This action draws oil out of the tank via the standpipe. At the same time, oil is sprayed into the tank in a fine mist, thereby exposing a large amount of oil to the vacuum. When the oil level in the tank falls below the lower of two level switches, a vacuum pump is started, drawing a hard vacuum on the tank through a trap that collects any oil and water entrained in the airflow. When the oil level rises above higher of the two level switches or when the system is shut down, a solenoid valve between the tank and the vacuum pump is closed to prevent suction of oil into the vacuum pump. Critical requirements that the system is designed to satisfy include the following: 1) The circulation pump must have sufficient volume and pressure to operate the venturi tube and spray nozzles. 2) The venturi tube must be sized to empty the tank (except for the oil retained by the standpipe) and maintain a vacuum against the vacuum pump. 3) The tank must be strong enough to withstand atmospheric pressure against the vacuum inside and must have sufficient volume to enable exposure of a sufficiently large amount of sprayed oil to the vacuum. 4) The spray nozzles must be sized to atomize the oil and to ensure that the rate of flow of sprayed oil does not exceed the rate at which the venturi action can empty the tank. 5) The vacuum pump must produce a hard vacuum against the venturi tube and continue to work when it ingests some oil and water. 6) Fittings must be made vacuum tight (by use of O-rings) to prevent leakage of air into the system. The system is fully automatic, and can be allowed to remain in operation with very little monitoring. It is capable of reducing the air content of the oil from 11 to less than 1 volume percent in about 4 hours and to keep the water content below 100 parts per million.

Comparison of intraocular pressure during the application of a liquid patient interface (FEMTO LDV Z8) for femtosecond laser-assisted cataract surgery using two different vacuum levels.

PubMed

Ebner, Martina; Mariacher, Siegfried; Januschowski, Kai; Boden, Katrin; Seuthe, Anna-Maria; Szurman, Peter; Boden, Karl Thomas

2017-08-01

To evaluate intraocular pressure (IOP) using the application of a novel liquid patient interface for femtosecond laser-assisted cataract surgery with the FEMTO LDV Z8. IOP was evaluated in enucleated porcine eyes prior, during and after the application of the Femto LDV Z8 liquid patient interface (Ziemer Ophthalmic Systems, Switzerland) using intracameral cannulation (n=20), intravitreal cannulation (n=20), rebound tonometry (n=20) and indentation tonometry (n=20). Pressure was assessed prior vacuum, during vacuum (30 s, 1 min, 2 min, 3 min) and after releasing the vacuum (1 min and 2 min). Two groups with different predefined vacuum levels (350 mbar, 420 mbar) were investigated. Mean intracameral pressure (±SD) increased during vacuum application from 20 mm Hg to 52.00 mm Hg (±6.35mm Hg; p=0.005) and 45.18 mmHg (±4.34 mm Hg; p=0.005) for the 420 mbar and the 350 mbar vacuum levels, respectively. Mean intravitreal pressure increased from 20 mm Hg to 25.60 mm Hg (±9.85 mm Hg; p=0.058) and 28.10 mm Hg (±2.54 mm Hg; p=0.059) for the 420 mbar and the 350 mbar vacuum levels, respectively. Pressure values from indentation and rebound tonometry were in between intracameral and intravitreal values. Mean intracameral IOP was 18.1% higher (p=0.019) in the 420 mbar group compared with the 350 mbar group. During vacuum application of the liquid patient interface of the Femto LDV Z8 for femtosecond laser-assisted cataract surgery, IOP values were higher in the anterior chamber compared with the intravitreal pressure measurements. The higher predefined vacuum level (350 mbar vs 420 mbar) resulted in significant higher intracameral IOP. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Short-term effects of vacuum massage on epidermal and dermal thickness and density in burn scars: an experimental study.

PubMed

Meirte, Jill; Moortgat, Peter; Anthonissen, Mieke; Maertens, Koen; Lafaire, Cynthia; De Cuyper, Lieve; Hubens, Guy; Van Daele, Ulrike

2016-01-01

Vacuum massage is a non-invasive mechanical massage technique invented to treat burns and scars. To date, no effects of vacuum massage on thickness and density of human scar tissue have been reported. The process in which external stimuli are converted into biochemical responses in the cell is known as mechanotransduction. In the skin endothelial cells, fibroblasts and myofibroblasts embedded in the extracellular matrix (ECM) sense mechanical stimuli (created by vacuum massage) and may promote intracellular processes leading to matrix remodelling. Since mechanotransduction could be a plausible working mechanism for vacuum massage as an anti-scarring therapy, this study aims to investigate the short-term effects of vacuum massage on thickness and density of epidermis and dermis in burn scars in order to find proof of ECM remodelling. A one group experimental study was performed. Patients with burn scars on upper extremities, lower extremities, and trunk were recruited for participation in this study. The DUB®cutis 22 MHz ultrasound scanner was used to assess thickness and density of the epidermal and dermal skin layers. After baseline measurements, vacuum massage was performed according to a pre-defined protocol. Measurements were carried out at 5 min, 30 min, 1 h, and 2 h post-intervention. Thirteen scar sites from 9 different patients were investigated. In 8 out of the 13 scar sites, a disruption of the epidermis was noticed after the vacuum massage. Five minutes after the intervention, epidermal density decreased statistically significantly (p = .022) and dermal thickness increased (p = .018). Both changes lasted for more than 1 h, but after 2 h, the changes were no longer statistically significant. Dermal density decreased significantly (p = .048) immediately after the intervention, and this decrease was still present after 2 h (p = .011). Preliminary results show that the disruption of the epidermis may indicate that vacuum massage could be able to actually breach the skin barrier. The statistically significant changes in the dermal layers could suggest an increased ECM production after vacuum massage.

A review of vacuum ARC ion source research at ANSTO

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

Evans, P.J.; Noorman, J.T.; Watt, G.C.

1996-08-01

The authors talk briefly describes the history and current status of vacuum arc ion source research at the Australian Nuclear Science and Technology Organization (ANSTO). In addition, the author makes some mention of the important role of previous Vacuum Arc Ion Source Workshops in fostering the development of this research field internationally. During the period 1986 - 89, a type of plasma centrifuge known as a vacuum arc centrifuge was developed at ANSTO as part of a research project on stable isotope separation. In this device, a high current vacuum arc discharge was used to produce a metal plasma whichmore » was subsequently rotated in an axial magnetic field. The high rotational speeds (10{sup 5} - 10{sup 6} rad sec{sup {minus}1}) achievable with this method produce centrifugal separation of ions with different mass:charge ratios such as isotopic species. The first portent of things to come occurred in 1985 when Dr. Ian Brown visited ANSTO`s Lucas Heights Research Laboratories and presented a talk on the metal vapour vacuum arc (MEVVA) ion source which had only recently been invented by Brown and co-workers, J. Galvin and R. MacGill, at Lawrence Berkeley Laboratory. For those of us involved in vacuum arc centrifuge research, this was an exciting development primarily because the metal vapour vacuum arc plasma source was common to both devices. Thus, a type of arc, which had since the 1930`s been extensively investigated as a means of switching high current loads, had found wider application as a useful plasma source.« less

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

Haseler, Luke J., E-mail: l.haseler@griffith.edu.au; Sibbitt, Randy R., E-mail: THESIBB2@aol.com; Sibbitt, Wilmer L., E-mail: wsibbitt@salud.unm.edu

Purpose: Syringes are used for diagnostic fluid aspiration and fine-needle aspiration biopsy in interventional procedures. We determined the benefits, disadvantages, and patient safety implications of syringe and needle size on vacuum generation, hand force requirements, biopsy/fluid yield, and needle control during aspiration procedures. Materials and Methods: Different sizes (1, 3, 5, 10, and 20 ml) of the conventional syringe and aspirating mechanical safety syringe, the reciprocating procedure device, were studied. Twenty operators performed aspiration procedures with the following outcomes measured: (1) vacuum (torr), (2) time to vacuum (s), (3) hand force to generate vacuum (torr-cm{sup 2}), (4) operator difficulty duringmore » aspiration, (5) biopsy yield (mg), and (6) operator control of the needle tip position (mm). Results: Vacuum increased tissue biopsy yield at all needle diameters (P < 0.002). Twenty-milliliter syringes achieved a vacuum of -517 torr but required far more strength to aspirate, and resulted in significant loss of needle control (P < 0.002). The 10-ml syringe generated only 15% less vacuum (-435 torr) than the 20-ml device and required much less hand strength. The mechanical syringe generated identical vacuum at all syringe sizes with less hand force (P < 0.002) and provided significantly enhanced needle control (P < 0.002). Conclusions: To optimize patient safety and control of the needle, and to maximize fluid and tissue yield during aspiration procedures, a two-handed technique and the smallest syringe size adequate for the procedure should be used. If precise needle control or one-handed operation is required, a mechanical safety syringe should be considered.« less

Effect of fabrication parameters on coating properties of tubular solid oxide fuel cell electrolyte prepared by vacuum slurry coating

NASA Astrophysics Data System (ADS)

Son, Hui-Jeong; Song, Rak-Hyun; Lim, Tak-Hyoung; Lee, Seung-Bok; Kim, Sung-Hyun; Shin, Dong-Ryul

The process of vacuum slurry coating for the fabrication of a dense and thin electrolyte film on a porous anode tube is investigated for application in solid oxide fuel cells. 8 mol% yttria stabilized zirconia is coated on an anode tube by vacuum slurry-coating process as a function of pre-sintering temperature of the anode tube, vacuum pressure, slurry concentration, number of coats, and immersion time. A dense electrolyte layer is formed on the anode tube after final sintering at 1400 °C. With decrease in the pre-sintering temperature of the anode tube, the grain size of the coated electrolyte layer increases and the number of surface pores in the coating layer decreases. This is attributed to a reduced difference in the respective shrinkage of the anode tube and the electrolyte layer. The thickness of the coated electrolyte layer increases with the content of solid powder in the slurry, the number of dip-coats, and the immersion time. Although vacuum pressure has no great influence on the electrolyte thickness, higher vacuum produces a denser coating layer, as confirmed by low gas permeability and a reduced number of defects in the coating layer. A single cell with the vacuum slurry coated electrolyte shows a good performance of 620 mW cm -2 (0.7 V) at 750 °C. These experimental results indicate that the vacuum slurry-coating process is an effective method to fabricate a dense thin film on a porous anode support.

Recovery of materials from waste printed circuit boards by vacuum pyrolysis and vacuum centrifugal separation.

PubMed

Zhou, Yihui; Wu, Wenbiao; Qiu, Keqiang

2010-11-01

In this research, a two-step process consisting of vacuum pyrolysis and vacuum centrifugal separation was employed to treat waste printed circuit boards (WPCBs). Firstly, WPCBs were pyrolysed under vacuum condition at 600 °C for 30 min in a lab-scale reactor. Then, the obtained pyrolysis residue was heated under vacuum until the solder was melted, and then the molten solder was separated from the pyrolysis residue by the centrifugal force. The results of vacuum pyrolysis showed that the type-A of WPCBs (the base plates of which was made from cellulose paper reinforced phenolic resin) pyrolysed to form an average of 67.97 wt.% residue, 27.73 wt.% oil, and 4.30 wt.% gas; and pyrolysis of the type-B of WPCBs (the base plates of which was made from glass fiber reinforced epoxy resin) led to an average mass balance of 72.20 wt.% residue, 21.45 wt.% oil, and 6.35 wt.% gas. The results of vacuum centrifugal separation showed that the separation of solder was complete when the pyrolysis residue was heated at 400 °C, and the rotating drum was rotated at 1200 rpm for 10 min. The pyrolysis oil and gas can be used as fuel or chemical feedstock after treatment. The pyrolysis residue after solder separation contained various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The recovered solder can be reused directly and it can also be a good resource of lead and tin for refining. Copyright © 2010 Elsevier Ltd. All rights reserved.

Nonperturbative vacuum polarization effects in two-dimensional supercritical Dirac-Coulomb system II. Vacuum energy

NASA Astrophysics Data System (ADS)

Davydov, A.; Sveshnikov, K.; Voronina, Yu.

2018-01-01

Nonperturbative vacuum polarization effects are explored for a supercritical Dirac-Coulomb system with Z > Zcr,1 in 2+1D, based on the original combination of analytical methods, computer algebra and numerical calculations, proposed recently in Refs. 1-3. Both the vacuum charge density ρV P(r→) and vacuum energy ℰV P are considered. Due to a lot of details of calculation the whole work is divided into two parts I and II. Taking account of results, obtained in the part I4 for ρV P, in the present part II, the evaluation of the vacuum energy ℰV P is investigated with emphasis on the renormalization and convergence of the partial expansion for ℰV P. It is shown that the renormalization via fermionic loop turns out to be the universal tool, which removes the divergence of the theory both in the purely perturbative and essentially nonperturbative regimes of the vacuum polarization. The main result of calculation is that for a wide range of the system parameters in the overcritical region ℰV P turns out to be a rapidly decreasing function ˜-ηeffZ3/R with ηeff > 0 and R being the size of the external Coulomb source. To the end the similarity in calculations of ℰV P in 2+1 and 3+1D is discussed, and qualitative arguments are presented in favor of the possibility for complete screening of the classical electrostatic energy of the Coulomb source by the vacuum polarization effects for Z ≫ Zcr,1 in 3+1D.

Rubber-coated bellows improves vibration damping in vacuum lines

NASA Technical Reports Server (NTRS)

Hegland, D. E.; Smith, R. J.

1966-01-01

Compact-vibration damping systems, consisting of rubber-coated metal bellows with a sliding O-ring connector, are used in vacuum lines. The device presents a metallic surface to the vacuum system and combines flexibility with the necessary stiffness. It protects against physical damage, reduces fatigue failure, and provides easy mating of nonparallel lines.

Breather cloth for vacuum curing

NASA Technical Reports Server (NTRS)

Reed, M. W.

1979-01-01

Finely-woven nylon cloth that has been treated with Teflon improves vacuum adhesive bonding of coatings to substrates. Cloth is placed over coating; entire assembly, including substrate, coating, and cloth, is placed in plastic vacuum bag for curing. Cloth allows coating to "breathe" when bag is evacuated. Applications include bonding film coatings to solar concentrators and collectors.

Flux tubes in the SU(3) vacuum

NASA Astrophysics Data System (ADS)

Cardaci, M. S.; Cea, P.; Cosmai, L.; Falcone, R.; Papa, A.

We analyze the distribution of the chromoelectric field generated by a static quark-antiquark pair in the SU(3) vacuum. We find that the transverse profile of the flux tube resembles the dual version of the Abrikosov vortex field distribution and give an estimate of the London penetration length in the confined vacuum.

46 CFR 154.1335 - Pressure and vacuum protection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Pressure and vacuum protection. 154.1335 Section 154... Equipment Instrumentation § 154.1335 Pressure and vacuum protection. (a) Each cargo tank must have the following: (1) A pressure gauge that: (i) Monitors the vapor space; (ii) Is readable at the tank; and (iii...

PERFORMANCE OF AIR SPARGING AND SOIL VACUUM EXTRACTION FOR TREATMENT OF MTBE AND BENZENE AT UST SITES IN KANSAS

EPA Science Inventory

The efficacy of soil vacuum extraction or air sparging and soil vacuum extraction for remediation of ground water contamination with MTBE was compared to remediation of contamination with benzene. There was no practical difference.
Sites were identified that met the followin...

49 CFR 195.264 - Impoundment, protection against entry, normal/emergency venting or pressure/vacuum relief for...

Code of Federal Regulations, 2010 CFR

2010-10-01

... devices must be provided for each low-pressure and high-pressure breakout tank. (e) For normal/emergency... and vacuum-relieving devices installed on high pressure tanks built to API Standard 2510 (incorporated.../emergency venting or pressure/vacuum relief for aboveground breakout tanks. 195.264 Section 195.264...

Vacuum Gas Tungsten Arc Welding

NASA Technical Reports Server (NTRS)

Weeks, J. L.; Todd, D. T.; Wooten, J. R.

1997-01-01

A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

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

NASA Astrophysics Data System (ADS)

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

2015-03-01

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

Vacuum Vaporization Technique for Latent Fingerprints Development on Thermal Papers using Lawsone Natural Products

NASA Astrophysics Data System (ADS)

Phungyimnoi, N.; Eksinitkun, G.; Phutdhawong, W.

2017-09-01

The vacuum vaporization technique is widely used to develop of visualized latent fingerprints on substrate surface for forensics investigation. In this study, we reported the first utilization of lawsone in the vacuum vaporization technique. The lawsone was sublimation in vacuum and showed the detected latent fingerprints on thermal papers. The method involves hanging the thermal paper samples 5, 10, 15 cm above a heating source with dispersed lawsone solids in a vacuum chamber. The optimized condition for lawsone sublimation are 50, 100, 150 mg with low-vacuum (0.1 mbar) and vaporizing temperature at 40-60°C. The sample fingerprints were left for 1, 3, 7 and 30 days before examination comparison between lawsone and fingerprint ink pad using an Automated Fingerprint Identification (AFIS). The resulted showed that using 100 mg lawsone sublimation on thermal paper at the range of 10 cm evidenced the clear, detectable minutiae which can be used for visualization and identification of latent prints without the background black staining known. Thus, this study might be interested application for developing latent fingerprints as a solvent free technique and non-hazardous materials.

Effect of a commercial steam-vacuuming treatment implemented after slaughtering for the decontamination of cattle carcasses

PubMed Central

Hochreutener, Mirjam; Zweifel, Claudio; Corti, Sabrina; Stephan, Roger

2017-01-01

To assess the antimicrobial effect of a commercial steam-vacuuming system newly implemented after slaughtering, 105 cattle carcasses were examined for total viable counts (TVC) at four different areas. Before steam vacuuming, mean TVC of the excision samples were comparable at the perineal area and brisket (3.0-3.1 log CFU cm-2) or the hind leg and shoulder (2.6-2.7 log CFU cm-2). Steam vacuuming reduced mean TVC by 0.9, 0.7, 0.6, and 0.4 log CFU cm-2 at the perineal area, hind leg, shoulder, and brisket, respectively. With regard to the distribution of counts, steam vacuuming increased the proportion of TVC results <3.0 log CFU cm-2 from 74.8% (62.9-87.6% at carcass areas) to 86.7% (71.4-97.1% at carcass areas). Thus, steam vacuuming after slaughtering might be useful for the reduction of contamination in designated carcass areas, but the effect must not be overestimated and decontamination treatments always must be seen part of an integral food safety system. PMID:29071245

Global Resolution of the Physical Vacuum Singularity for Three-Dimensional Isentropic Inviscid Flows with Damping in Spherically Symmetric Motions

NASA Astrophysics Data System (ADS)

Zeng, Huihui

2017-10-01

For the gas-vacuum interface problem with physical singularity and the sound speed being {C^{{1}/{2}}}-Hölder continuous near vacuum boundaries of the isentropic compressible Euler equations with damping, the global existence of smooth solutions and the convergence to Barenblatt self-similar solutions of the corresponding porous media equation are proved in this paper for spherically symmetric motions in three dimensions; this is done by overcoming the analytical difficulties caused by the coordinate's singularity near the center of symmetry, and the physical vacuum singularity to which standard methods of symmetric hyperbolic systems do not apply. Various weights are identified to resolve the singularity near the vacuum boundary and the center of symmetry globally in time. The results obtained here contribute to the theory of global solutions to vacuum boundary problems of compressible inviscid fluids, for which the currently available results are mainly for the local-in-time well-posedness theory, and also to the theory of global smooth solutions of dissipative hyperbolic systems which fail to be strictly hyperbolic.

Maximum Expected Wall Heat Flux and Maximum Pressure After Sudden Loss of Vacuum Insulation on the Stratospheric Observatory for Infrared Astronomy (SOFIA) Liquid Helium (LHe) Dewars

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.

2014-01-01

The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared observation experiments. The experiments carry sensors cooled to liquid helium (LHe) temperatures. A question arose regarding the heat input and peak pressure that would result from a sudden loss of the dewar vacuum insulation. Owing to concerns about the adequacy of dewar pressure relief in the event of a sudden loss of the dewar vacuum insulation, the SOFIA Program engaged the NASA Engineering and Safety Center (NESC). This report summarizes and assesses the experiments that have been performed to measure the heat flux into LHe dewars following a sudden vacuum insulation failure, describes the physical limits of heat input to the dewar, and provides an NESC recommendation for the wall heat flux that should be used to assess the sudden loss of vacuum insulation case. This report also assesses the methodology used by the SOFIA Program to predict the maximum pressure that would occur following a loss of vacuum event.

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

PubMed

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.

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

PubMed

Zhan, Lu; Xu, Zhenming

2014-12-16

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

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

PubMed

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).

The influence of a central vacuum system on quality life in patients with house dust-associated allergic rhinitis.

PubMed

Naguwa, S M; Gershwin, M E

2001-01-01

Indoor pollution is one of the most common problems addressed by allergists and troublesome for their patients. Although a large variety of products are available for removing such pollutants, including house dust, there is a relative paucity of data on the effectiveness of such devices. In many cases, central vacuum systems are recommended, particularly in new homes. To specifically address the question of whether a central vacuum system produces an improvement in the well characterized domains of Juniper Rhinoconjunctivitis Quality of Life Questionnaire, we selected 25 individuals with a history of documented type I hypersensitivity to house dust. Each of these individuals used either a Beam Central Vacuum System or their own conventional vacuum for a period of 3 months. At the end of this period, the individual switched over to the opposite limb of the study for 3 additional months. Interestingly, in all seven domains of the evaluation, including activity, sleep, nonnasal symptoms, practical problems, nasal symptoms, eye symptoms and emotions, use of the central vacuum proved to be superior.

VACUUM TRAP AND VALVE COMBINATION

DOEpatents

Milleron, N.; Levenson, L.

1963-02-19

This patent relates to a vacuum trap and valve combination suitable for use in large ultra-high vacuum systems. The vacuum trap is a chamber having an inlet and outlet opening which may be made to communicate with a chamber to be evacuated and a diffusion pump, respectively. A valve is designed to hermeticaliy seal with inlet opening and, when opened, block the line-of- sight'' between the inlet and outlet openings, while allowing a large flow path between the opened vaive and the side walls of the trap. The interior of the trap and the side of the valve facing the inlet opening are covered with an impurity absorbent, such as Zeolite or activated aluminum. Besides the advantage of combining two components of a vacuum system into one, the present invention removes the need for a baffle between the pump and the chamber to be evacuated. In one use of a specific embodiment of this invention, the transmission probability was 45 and the partial pressure of the pump fluid vapor in the vacuum chamber was at least 100 times lower than its vapor pressure. (AEC)

Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters

PubMed Central

Calfee, M. Worth; Rose, Laura J.; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

2016-01-01

The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37 mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p ≤ 0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p > 0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident. PMID:24184312

Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters.

PubMed

Calfee, M Worth; Rose, Laura J; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

2014-01-01

The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p≤0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p>0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident. Published by Elsevier B.V.

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

PubMed

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

2015-03-01

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

Evaluation of supercapacitors for space applications under thermal vacuum conditions

NASA Astrophysics Data System (ADS)

Chin, Keith C.; Green, Nelson W.; Brandon, Erik J.

2018-03-01

Commercially available supercapacitor cells from three separate vendors were evaluated for use in a space environment using thermal vacuum (Tvac) testing. Standard commercial cells are not hermetically sealed, but feature crimp or double seam seals between the header and the can, which may not maintain an adequate seal under vacuum. Cells were placed in a small vacuum chamber, and cycled between three separate temperature set points. Charging and discharging of cells was executed following each temperature soak, to confirm there was no significant impact on performance. A final electrical performance check, visual inspection and mass check following testing were also performed, to confirm the integrity of the cells had not been compromised during exposure to thermal cycling under vacuum. All cells tested were found to survive this testing protocol and exhibited no significant impact on electrical performance.

Fate of electroweak vacuum during preheating

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

Ema, Yohei; Mukaida, Kyohei; Nakayama, Kazunori

2016-10-28

Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after inflation, the additional mass term oscillates, and it can destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper, we study whether or not the Higgs-inflaton/-curvature coupling can save our vacuum bymore » properly taking account of Higgs production during the preheating stage. We put upper bounds on the Higgs-inflaton and -curvature couplings, and discuss possible dynamics that might relax them.« less

Effect of double vacuum melting and retained austenite on rolling-element fatigue life of AMS 5749 bearing steel

NASA Technical Reports Server (NTRS)

Parker, R. J.; Hodder, R. S.

1977-01-01

AMS 5749 steel combines the tempering, hot hardness, and hardness retention characteristics of AISI M-50 steel with the corrosion and oxidation resistance of AISI 440C stainless steel. The five-ball fatigue tester was used to evaluate the rolling-element fatigue life of AMS 5749. Double vacuum melting (vacuum induction melting plus vacuum arc remelting, VIM-VAR) produced AMS 5749 material with a rolling-element fatigue life at least 14 times that of vacuum induction melting alone. The VIM-VAR AMS 5749 steel balls gave lives from 6 to 12 times greater than VIM-VAR AISI M-50 steel balls. The highest level of retained austenite, 14.6 percent, was significantly detrimental to rolling-element fatigue life relative to the intermediate level of 11.1 percent.

Cosmic R-string, R-tube and vacuum instability

NASA Astrophysics Data System (ADS)

Eto, Minoru; Hamada, Yuta; Kamada, Kohei; Kobayashi, Tatsuo; Ohashi, Keisuke; Ookouchi, Yutaka

2013-03-01

We show that a cosmic string associated with spontaneous U(1) R symmetry breaking gives a constraint for supersymmetric model building. In some models, the string can be viewed as a tube-like domain wall with a winding number interpolating a false vacuum and a true vacuum. Such string causes inhomogeneous decay of the false vacuum to the true vacuum via rapid expansion of the radius of the tube and hence its formation would be inconsistent with the present Universe. However, we demonstrate that there exist metastable solutions which do not expand rapidly. Furthermore, when the true vacua are degenerate, the structure inside the tube becomes involved. As an example, we show a "bamboo"-like solution, which suggests a possibility observing an information of true vacua from outside of the tube through the shape and the tension of the tube.

Evaluation tests of industrial vacuum bearings for space use

NASA Astrophysics Data System (ADS)

Obara, S.; Sasaki, A.; Haraguchi, M.; Imagawa, K.; Nishimura, M.; Kawashima, N.

2001-09-01

Tribological performance of industrial vacuum bearings was experimentally evaluated for space use. The bearings selected for investigation were an 8 mm bore-sized deep-groove ball bearing lubricated with a sputtered MoS2 film and that lubricated with an ion-plated Ag film, commercially delivered from three Japanese domestic bearing-manufacturers. Based on survey results of tribological requirements for the existing satellite mechanisms, four types of bearing tests were defined and conducted: a vacuum test at room temperature, an atmosphere-resistant test, a thermal vacuum test and a vibration test. In addition to these tests, variation in tribological performance of the industrial bearings was also investigated. The results of more than eighty tests demonstrated that the industrial vacuum bearings had sufficient lubrication lives with low frictional torque and their data were reasonably repeatable, indicating very good potentiality for space use.

Improved Thermal-Vacuum Compatible Flat Plate Radiometric Source For System-Level Testing Of Optical Sensors

NASA Technical Reports Server (NTRS)

Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

2016-01-01

In this work, we describe an improved thermal-vacuum compatible flat plate radiometric source which has been developed and utilized for the characterization and calibration of remote optical sensors. This source is unique in that it can be used in situ, in both ambient and thermal-vacuum environments, allowing it to follow the sensor throughout its testing cycle. The performance of the original flat plate radiometric source was presented at the 2009 SPIE1. Following the original efforts, design upgrades were incorporated into the source to improve both radiometric throughput and uniformity. The pre-thermal-vacuum (pre-TVAC) testing results of a spacecraft-level optical sensor with the improved flat plate illumination source, both in ambient and vacuum environments, are presented. We also briefly discuss potential FPI configuration changes in order to improve its radiometric performance.

Quantitative study of sniffer leak rate and pressure drop leak rate of liquid nitrogen panels of SST-1 tokamak

NASA Astrophysics Data System (ADS)

Pathan, F. S.; Khan, Z.; Semwal, P.; Raval, D. C.; Joshi, K. S.; Thankey, P. L.; Dhanani, K. R.

2008-05-01

Steady State Super-conducting (SST-1) Tokamak is in commissioning stage at Institute for Plasma Research. Vacuum chamber of SST-1 Tokamak consists of 1) Vacuum vessel, an ultra high vacuum (UHV) chamber, 2) Cryostat, a high vacuum (HV) chamber. Cryostat encloses the liquid helium cooled super-conducting magnets (TF and PF), which require the thermal radiation protection against room temperature. Liquid nitrogen (LN2) cooled panels are used to provide thermal shield around super-conducting magnets. During operation, LN2 panels will be under pressurized condition and its surrounding (cryostat) will be at high vacuum. Hence, LN2 panels must have very low leak rate. This paper describes an experiment to study the behaviour of the leaks in LN2 panels during sniffer test and pressure drop test using helium gas.

National Synchrotron Light Source II storage ring vacuum systems

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

Hseuh, Hsiao-Chaun, E-mail: hseuh@bnl.gov; Hetzel, Charles; Leng, Shuwei

2016-05-15

The National Synchrotron Light Source II, completed in 2014, is a 3-GeV synchrotron radiation (SR) facility at Brookhaven National Laboratory and has been in steady operation since. With a design electron current of 500 mA and subnanometer radians horizontal emittance, this 792-m circumference storage ring is providing the highest flux and brightness x-ray beam for SR users. The majority of the storage ring vacuum chambers are made of extruded aluminium. Chamber sections are interconnected using low-impedance radiofrequency shielded bellows. SR from the bending magnets is intercepted by water-cooled compact photon absorbers resided in the storage ring chambers. This paper presents themore » design of the storage ring vacuum system, the fabrication of vacuum chambers and other hardware, the installation, the commissioning, and the continuing beam conditioning of the vacuum systems.« less

Relaxation of vacuum energy in q-theory

NASA Astrophysics Data System (ADS)

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.

Development of High vacuum facility for baking and cool down experiments for SST-1 Tokamak components

NASA Astrophysics Data System (ADS)

Khan, Ziauddin; Pathan, Firozkhan S.; Yuvakiran, Paravastu; George, Siju; Manthena, Himabindu; Raval, Dilip C.; Thankey, Prashant L.; Dhanani, Kalpesh R.; Gupta, Manoj Kumar; Pradhan, Subrata

2012-11-01

SST-1 Tokamak, a steady state super-conducting device, is under refurbishment to demonstrate the plasma discharge for the duration of 1000 second. The major fabricated components of SST-1 like vacuum vessel, thermal shields, superconducting magnets etc have to be tested for their functional parameters. During machine operation, vacuum vessel will be baked at 150 °C, thermal shields will be operated at 85 K and magnet system will be operated at 4.5 K. All these components must have helium leak tightness under these conditions so far as the machine operation is concerned. In order to validate the helium leak tightness of these components, in-house high vacuum chamber is fabricated. This paper describes the analysis, design and fabrication of high vacuum chamber to demonstrate these functionalities. Also some results will be presented.

The Effect of Temperature on the Survival of Microorganisms in a Deep Space Vacuum

NASA Technical Reports Server (NTRS)

Hagen, C. A.; Godfrey, J. F.; Green, R. H.

1971-01-01

A space molecular sink research facility (Molsink) was used to evaluate the ability of microorganisms to survive the vacuum of outer space. This facility could be programmed to simulate flight spacecraft vacuum environments at pressures in the .1 nanotorr range and thermal gradients (30 to 60 C) closely associated to surface temperatures of inflight spacecraft. Initial populations of Staphylococcus epidermidis and a Micrococcus sp. were reduced approximately 1 log while exposed to -105 and 34 C, and approximately 2 logs while exposed to 59 C for 14 days in the vacuum environment. Spores of Bacillus subtilis var. niger were less affected by the environment. Initial spore populations were reduced 0.2, 0.3, and 0.8 log during the 14-day vacuum exposure at -124, 34, and 59 C, respectively.

Extreme ultraviolet (EUV) and FUV calibration facility for special sensor ultraviolet limb imager (SSULI)

NASA Astrophysics Data System (ADS)

Boyer, Craig N.; Osterman, Steven N.; Thonnard, Stefan E.; McCoy, Robert P.; Williams, J. Z.; Parker, S. E.

1994-09-01

A facility for calibrating far ultraviolet and extreme ultraviolet instruments has recently been completed at the Naval Research Laboratory. Our vacuum calibration vessel is 2-m in length, 1.67-m in diameter, and can accommodate optical test benches up to 1.2-m wide by 1.5-m in length. A kinematically positioned frame with four axis precision pointing capability of 10 microns for linear translation and .01 degrees for rotation is presently used during vacuum optical calibration of SSULI. The chamber was fabricated from 304 stainless steel and polished internally to reduce surface outgassing. A dust-free environment is maintained at the rear of the vacuum chamber by enclosing the 2-m hinged vacuum access door in an 8 ft. by 8 ft. class 100 clean room. Every effort was made to obtain an oil-free environment within the vacuum vessel. Outgassing products are continually monitored with a 1 - 200 amu residual gas analyzer. An oil-free claw and vane pump evacuates the chamber to 10-2 torr through 4 in. diameter stainless steel roughing lines. High vacuum is achieved and maintained with a magnetically levitated 480 l/s turbo pump and a 3000 l/s He4 cryopump. Either of two vacuum monochrometers, a 1-m f/10.4 or a 0.2-m f/4.5 are coaxially aligned with the optical axis of the chamber and are used to select single UV atomic resonance lines from a windowless capillary or penning discharge UV light source. A calibrated channeltron detector is coaxially mounted with the SSULI detector during calibration. All vacuum valves, the cooling system for the cryopump compressor, and the roughing pump are controlled through optical fibers which are interfaced to a computer through a VME board. Optical fibers were chosen to ensure that complete electrical isolation is maintained between the computer and the vacuum system valves-solenoids and relays.

Effects of vigorous mixing of blood vacuum tubes on laboratory test results.

PubMed

Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Gelati, Matteo; Volanski, Waldemar; Boritiza, Katia Cristina; Picheth, Geraldo; Guidi, Gian Cesare

2013-02-01

To evaluate the effect of tubes mixing (gentle vs. vigorous) on diagnostic blood specimens collected in vacuum tube systems by venipuncture. Blood was collected for routine coagulation, immunochemistry and hematological testing from one hundred volunteers into six vacuum tubes: two 3.6 mL vacuum tubes containing 0.4 mL of buffered sodium citrate (9NC) 0.109 mol/L: 3.2 W/V%; two 3.5 mL vacuum tubes with clot activator and gel separator; and two 3.0 mL vacuum tubes containing 5.9 mg K(2)EDTA (Terumo Europe, Belgium). Immediately after the venipuncture all vacuum tubes (each of one additive type) were processed through two different procedures: i) Standard: blood specimens in K(2)EDTA- or sodium citrate-vacuum tubes were gently inverted five times whereas the specimens in tubes with clot activator and gel separator were gently inverted ten times, as recommended by the manufacturer; ii) Vigorous mix: all blood specimens were shaken up vigorously during 3-5s independently of the additive type inside the tubes. The significance of the differences between samples was assessed by Student's t-test or Wilcoxon ranked-pairs test after checking for normality. The level of statistical significance was set at P<0.05. No significant difference (P<0.05) was detected between the procedures for all tested parameters. Surprisingly only a visual alteration (presence of foam on the top) was shown by all the tubes mixed vigorously before centrifugation (Fig. 1 A, B and C). Moreover the serum tubes from vigorous mixing procedure shows a "blood ring" on the tube top after stopper removal (Fig. 1 D). Our results drop out a paradigm suggesting that the incorrect primary blood tubes mixing promotes laboratory variability. We suggest that similar evaluation should be done using other brands of vacuum tubes by each laboratory manager. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Measurement of partial pressures in vacuum technology and vacuum physics

NASA Technical Reports Server (NTRS)

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.

Entanglement Equilibrium and the Einstein Equation.

PubMed

Jacobson, Ted

2016-05-20

A link between the semiclassical Einstein equation and a maximal vacuum entanglement hypothesis is established. The hypothesis asserts that entanglement entropy in small geodesic balls is maximized at fixed volume in a locally maximally symmetric vacuum state of geometry and quantum fields. A qualitative argument suggests that the Einstein equation implies the validity of the hypothesis. A more precise argument shows that, for first-order variations of the local vacuum state of conformal quantum fields, the vacuum entanglement is stationary if and only if the Einstein equation holds. For nonconformal fields, the same conclusion follows modulo a conjecture about the variation of entanglement entropy.

Variational methods in supersymmetric lattice field theory: The vacuum sector

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

Duncan, A.; Meyer-Ortmanns, H.; Roskies, R.

1987-12-15

The application of variational methods to the computation of the spectrum in supersymmetric lattice theories is considered, with special attention to O(N) supersymmetric sigma models. Substantial cancellations are found between bosonic and fermionic contributions even in approximate Ansa$uml: tze for the vacuum wave function. The nonlinear limit of the linear sigma model is studied in detail, and it is shown how to construct an appropriate non-Gaussian vacuum wave function for the nonlinear model. The vacuum energy is shown to be of order unity in lattice units in the latter case, after infinite cancellations.

Large numbers hypothesis. IV - The cosmological constant and quantum physics

NASA Technical Reports Server (NTRS)

Adams, P. J.

1983-01-01

In standard physics quantum field theory is based on a flat vacuum space-time. This quantum field theory predicts a nonzero cosmological constant. Hence the gravitational field equations do not admit a flat vacuum space-time. This dilemma is resolved using the units covariant gravitational field equations. This paper shows that the field equations admit a flat vacuum space-time with nonzero cosmological constant if and only if the canonical LNH is valid. This allows an interpretation of the LNH phenomena in terms of a time-dependent vacuum state. If this is correct then the cosmological constant must be positive.

The effect of vacuum devices on penile hemodynamics

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

Katz, P.G.; Haden, H.T.; Mulligan, T.

1990-01-01

External vacuum devices are being used increasingly for the management of erectile dysfunction. There is limited information regarding the effect of vacuum devices on penile blood flow and potential for ischemic penile injury. The penile xenon washout rate was measured before and after application of 2 vacuum systems in 15 subjects. Compared to flaccid state measurements the xenon washout rate did not change significantly with the Synergist Erection System but it was significantly reduced with the Osbon ErecAid System. However, the degree and duration of decrease in penile blood flow that may result in ischemic changes are unknown.

Implementation of Individual System Qualification (ISQ) in a CBRN Respiratory Protection Program, Part B: Standard Operating Procedures

DTIC Science & Technology

2014-10-01

or V2) on the side that is being tested. f. Plug the threaded hole in the face-form with a wetted finger. g. Gently pump the vacuum bulb enough to...a stop watch for a 45 second count down. 8. Close the bleed valve on the appropriate vacuum squeeze bulb (V1 or V2). Pump the bulb to draw a... vacuum into the mask until the gauge reaches or exceeds the green section of the dial (Figure 6). Generally 2 pumps will be sufficient. If the vacuum will

Power and Thermal Technologies for Air and Space -- Scientific Research Program. Delivery Order 0016: Developing and Processing High Energy Density Polymer Film Dielectrics for High Temperature Air Force Power Electronic Applications

DTIC Science & Technology

2010-01-01

a vacuum controller. A vacuum of < 1 µ torr was achieved with a combination of a turbo pump and a scroll pump system. The sample probing is...the polymer was reprecipitated in heptane non-solvent. The filtered polymer was washed with heptane and was finally dried in vacuum at 100ºC for three...solution was added to a large excess of methanol to precipitate the polymer. After soxhlet extraction with methanol and vacuum drying, the polymer was

The Influence of AN Interacting Vacuum Energy on the Gravitational Collapse of a Star Fluid

NASA Astrophysics Data System (ADS)

Campos, M.

2014-02-01

To explain the accelerated expansion of the universe, models with interacting dark components has been considered in the literature. Generally, the dark energy component is physically interpreted as the vacuum energy. However, at the other side of the same coin, the influence of the vacuum energy in the gravitational collapse is a topic of scientific interest. Based in a simple assumption on the collapsed rate of the matter fluid density that is altered by the inclusion of a vacuum energy component that interacts with the matter fluid, we study the final fate of the collapse process.

The Quantum Phase-Dynamical Properties of the Squeezed Vacuum State Intensity-Couple Interacting with the Atom

NASA Technical Reports Server (NTRS)

Fan, An-Fu; Sun, Nian-Chun; Zhou, Xin

1996-01-01

The Phase-dynamical properties of the squeezed vacuum state intensity-couple interacting with the two-level atom in an ideal cavity are studied using the Hermitian phase operator formalism. Exact general expressions for the phase distribution and the associated expectation value and variance of the phase operator have been derived. we have also obtained the analytic results of the phase variance for two special cases-weakly and strongly squeezed vacuum. The results calculated numerically show that squeezing has a significant effect on the phase properties of squeezed vacuum.

Vacuum-induced Berry phases in single-mode Jaynes-Cummings models

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

Liu, Yu; Wei, L. F.; Jia, W. Z.

2010-10-15

Motivated by work [Phys. Rev. Lett. 89, 220404 (2002)] for detecting the vacuum-induced Berry phases with two-mode Jaynes-Cummings models (JCMs), we show here that, for a parameter-dependent single-mode JCM, certain atom-field states also acquired photon-number-dependent Berry phases after the parameter slowly changed and eventually returned to its initial value. This geometric effect related to the field quantization still exists, even if the field is kept in its vacuum state. Specifically, a feasible Ramsey interference experiment with a cavity quantum electrodynamics system is designed to detect the vacuum-induced Berry phase.

Things One Can Learn by Putting a Quadcopter in a Vacuum Chamber

NASA Astrophysics Data System (ADS)

Ayars, Eric; Goff, Tori; Williams, Kirk

2018-05-01

Quadcopters (also known as "drones") do not fly in vacuum. This is obvious enough that experimenting on one in a vacuum chamber would seem rather uninteresting, but there is one question that may be usefully addressed by such an experiment: the mechanism for yaw control. Quadcopters control yaw (rotation about the vertical axis) by differential rotor speed, and the question of whether those changes in rotor speed create yaw torque via conservation of angular momentum or via atmospheric drag can be addressed by "flying" a quadcopter in a vacuum where there is effectively zero atmospheric drag.

Cosmological implications of Higgs near-criticality.

PubMed

Espinosa, J R

2018-03-06

The Standard Model electroweak (EW) vacuum, in the absence of new physics below the Planck scale, lies very close to the boundary between stability and metastability, with the last option being the most probable. Several cosmological implications of this so-called 'near-criticality' are discussed. In the metastable vacuum case, the main challenges that the survival of the EW vacuum faces during the evolution of the Universe are analysed. In the stable vacuum case, the possibility of implementing Higgs inflation is critically examined.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).

The Influence of Vacuum Circuit Breakers and Different Motor Models on Switching Overvoltages in Motor Circuits

NASA Astrophysics Data System (ADS)

Wong, Cat S. M.; Snider, L. A.; Lo, Edward W. C.; Chung, T. S.

Switching of induction motors with vacuum circuit breakers continues to be a concern. In this paper the influence on statistical overvoltages of the stochastic characteristics of vacuum circuit breakers, high frequency models of motors and transformers, and network characteristics, including cable lengths and network topology are evaluated and a general view of the overvoltages phenomena is presented. Finally, a real case study on the statistical voltage levels and risk-of-failure resulting from switching of a vacuum circuit breaker in an industrial installation in Hong Kong is presented.

Vaporizable Scaffolds for Fabricating Thermoelectric Modules

NASA Technical Reports Server (NTRS)

Sakamoto, Jeffrey; Yen, Shiao-pin; Fleurial, Jean-Pierre; Paik, Jong-Ah

2006-01-01

A process for fabricating thermoelectric modules with vacuum gaps separating the thermoelectric legs has been conceived, and the feasibility of some essential parts of the process has been demonstrated. The vacuum gaps are needed to electrically insulate the legs from each other. The process involves the use of scaffolding in the form of sheets of a polymer to temporarily separate the legs by the desired distance, which is typically about 0.5 mm. During a bonding subprocess that would take place in a partial vacuum at an elevated temperature, the polymer would be vaporized, thereby creating the vacuum gaps.

Stabilities of Dried Suspensions of Influenza Virus Sealed in a Vacuum or Under Different Gases

PubMed Central

Greiff, Donald; Rightsel, Wilton A.

1969-01-01

Suspensions of purified influenza virus, dried to a 1.4% content of residual moisture by sublimation of ice in vacuo, were sealed in a vacuum or under different gases of high purity. The stabilities of the several preparations were determined by an accelerated storage test. Based on the times predicted for the dried preparations stored at different temperatures to lose 1 log of infectivity titer, the order of stabilities in relation to sealing in vacuum or under different gases was as follows: helium > hydrogen > vacuum > argon > nitrogen > oxygen > carbon dioxide. Images PMID:5797938

Cold cathode vacuum gauging system

DOEpatents

Denny, Edward C.

2004-03-09

A vacuum gauging system of the cold cathode type is provided for measuring the pressure of a plurality of separate vacuum systems, such as in a gas centrifuge cascade. Each casing is fitted with a gauge tube assembly which communicates with the vacuum system in the centrifuge casing. Each gauge tube contains an anode which may be in the form of a slender rod or wire hoop and a cathode which may be formed by the wall of the gauge tube. The tube is provided with an insulated high voltage connector to the anode which has a terminal for external connection outside the vacuum casing. The tube extends from the casing so that a portable magnet assembly may be inserted about the tube to provide a magnetic field in the area between the anode and cathode necessary for pressure measurements in a cold cathode-type vacuum gauge arrangement. The portable magnetic assembly is provided with a connector which engages the external high voltage terminal for providing power to the anode within in the gauge tube. Measurement is made in the same manner as the prior cold cathode gauges in that the current through the anode to the cathode is measured as an indication of the pressure. By providing the portable magnetic assembly, a considerable savings in cost, installation, and maintenance of vacuum gauges for pressure measurement in a gas centrifuge cascade is realizable.

Progress Toward Optimizing Prosthetic Socket Fit and Suspension Using Elevated Vacuum to Promote Residual Limb Health.

PubMed

Wernke, Matthew M; Schroeder, Ryan M; Haynes, Michael L; Nolt, Lonnie L; Albury, Alexander W; Colvin, James M

2017-07-01

Objective: Prosthetic sockets are custom made for each amputee, yet there are no quantitative tools to determine the appropriateness of socket fit. Ensuring a proper socket fit can have significant effects on the health of residual limb soft tissues and overall function and acceptance of the prosthetic limb. Previous work found that elevated vacuum pressure data can detect movement between the residual limb and the prosthetic socket; however, the correlation between the two was specific to each user. The overall objective of this work is to determine the relationship between elevated vacuum pressure deviations and prosthetic socket fit. Approach: A tension compression machine was used to apply repeated controlled forces onto a residual limb model with sockets of different internal volume. Results: The vacuum pressure-displacement relationship was dependent on socket fit. The vacuum pressure data were sensitive enough to detect differences of 1.5% global volume and can likely detect differences even smaller. Limb motion was reduced as surface area of contact between the limb model and socket was maximized. Innovation: The results suggest that elevated vacuum pressure data provide information to quantify socket fit. Conclusions: This study provides evidence that the use of elevated vacuum pressure data may provide a method for prosthetists to quantify and monitor socket fit. Future studies should investigate the relationship between socket fit, limb motion, and limb health to define optimal socket fit parameters.

Vacuum system design and tritium inventory for the charge exchange diagnostic on the Tokamak Fusion Test Reactor

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

Medley, S.S.

The application of charge exchange analyzers for the measurement of ion temperature in fusion plasma experiments requires a direct connection between the diagnostic and plasma-discharge vacuum chambers. Differential pumping of the gas load from the diagnostic stripping cell operated at > or approx. = 10/sup -3/ Torr is required to maintain the analyzer chamber at a pressure of < or approx. = 10/sup -6/ Torr. The migration of gases between the diagnostic and plasma vacuum chambers must be minimized. In particular, introduction of the analyzer stripping cell gas into the plasma chamber having a base pressure of < or approx.more » = 10/sup -8/ Torr must be suppressed. The charge exchange diagnostic for the Tokamak Fusion Test Reactor (TFTR) is comprised of two analyzer systems designed to contain a total of 18 independent mass/energy analyzers and one diagnostic neutral beam rated at 80 keV, 15 A. The associated arrays of multiple, interconnected vacuum systems were analyzed using the Vacuum System Transient Simulator (Vsts) computer program which models the transient transport of multigas species through complex networks of ducts, valves, traps, vacuum pumps, and other related vacuum system components. In addition to providing improved design performance at reduced costs, the analysis yields estimates for the exchange of tritium from the torus to the diagnostic components and of the diagnostic working gases to the torus.« less

Modification of fast-growing Chinese Fir wood with unsaturated polyester resin: Impregnation technology and efficiency

NASA Astrophysics Data System (ADS)

Ma, Qing; Zhao, Zijian; Yi, Songlin; Wang, Tianlong

In this study, Chinese Fir was impregnated with unsaturated polyester resin to enhance its properties. Samples 20 mm × 20 mm × 20 mm in size were split into different sections with epoxy resin and tinfoil and subjected to an impregnation experiment under various parameters. Vacuum degree was -0.04 MPa, -0.06 MPa or -0.08 MPa and vacuum duration was 15 min, 30 min, or 45 min. The results indicated that impregnation weight percent gain is linearly dependent on curing weight percent gain. Vacuum duration appears to have less influence on the curing weight percent gain than vacuum degree, and impregnation was most successful at the transverse section compared to other sections. The optimal impregnation parameters were 30 min modification under -0.08 MPa vacuum followed by 120 min at atmospheric pressure for samples 200 mm × 100 mm × 20 mm in size. Uneven distribution of weight percent gain and cracking during the curing process suggested that 30 min post-processing at -0.09 MPa vacuum was the most effective way to complete the impregnation process. The sample's bending strength and modulus of elasticity increased after impregnation treatment. Bending strength after impregnation without post-processing reached 112.85%, but reached 71.65% with vacuum-processing; modulus of elasticity improved 67.13% and 58.28% without and with post-processing, respectively.

Cosmological constant problem and renormalized vacuum energy density in curved background

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

Kohri, Kazunori; Matsui, Hiroki, E-mail: kohri@post.kek.jp, E-mail: matshiro@post.kek.jp

The current vacuum energy density observed as dark energy ρ{sub dark}≅ 2.5×10{sup −47} GeV{sup 4} is unacceptably small compared with any other scales. Therefore, we encounter serious fine-tuning problem and theoretical difficulty to derive the dark energy. However, the theoretically attractive scenario has been proposed and discussed in literature: in terms of the renormalization-group (RG) running of the cosmological constant, the vacuum energy density can be expressed as ρ{sub vacuum}≅ m {sup 2} H {sup 2} where m is the mass of the scalar field and rather dynamical in curved spacetime. However, there has been no rigorous proof to derivemore » this expression and there are some criticisms about the physical interpretation of the RG running cosmological constant. In the present paper, we revisit the RG running effects of the cosmological constant and investigate the renormalized vacuum energy density in curved spacetime. We demonstrate that the vacuum energy density described by ρ{sub vacuum}≅ m {sup 2} H {sup 2} appears as quantum effects of the curved background rather than the running effects of cosmological constant. Comparing to cosmological observational data, we obtain an upper bound on the mass of the scalar fields to be smaller than the Planck mass, m ∼< M {sub Pl}.« less

Overview of High Power Vacuum Dry RF Load Designs

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

Krasnykh, Anatoly

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 tomore » 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.« less

Construction of vacuum system for Tristan accumulation ring

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

Ishimaru, H.; Horikoshi, G.; Kobayashi, M.

1983-08-01

An all aluminum-alloy vacuum system for the TRISTAN accumulation ring is now under construction. Aluminum and aluminum alloys are preferred materials for ultrahigh vacuum systems of large electron storage rings because of their good thermal conductivity, extremely low outgassing rate, and low residual radioactivity. Vacuum beam chambers for the dipole and quadrupole magnets are extruded using porthole dies. The aluminum alloy 6063-T6 provides superior performance in extrusion. For ultrahigh vacuum performance, a special extrusion technique is applied which, along with the outgassing procedure used, is described in detail. Aluminum alloy 3004 seamless elliptical bellows are inserted between the dipole andmore » quadrupole magnet chambers. These bellows are produced by the hydraulic forming of a seamless tube. The seamless bellows and the beam chambers are joined by fully automatic welding. The ceramic chambers for the kicker magnets, the fast bump magnets, and the slow beam intensity monitor are inserted in the aluminum alloy beam chambers. The ceramic chamber (98% alumina) and elliptical bellows are brazed with brazing sheets (4003-3003-4003) in a vacuum furnace. The brazing technique is described. The inner surface of the ceramic chamber is coated with a TiMo alloy by vacuum evaporation to permit a smooth flow of the RF wall current. Other suitable aluminum alloy components, including fittings, feedthroughs, gauges, optical windows, sputter ion pumps, turbomolecular pumps, and valves have been developed; their fabrication is described.« less

Radio Frequency Trap for Containment of Plasmas in Antimatter Propulsion Systems Using Rotating Wall Electric Fields

NASA Technical Reports Server (NTRS)

Sims, William Herbert, III (Inventor); Martin, James Joseph (Inventor); Lewis, Raymond A. (Inventor)

2003-01-01

A containment apparatus for containing a cloud of charged particles comprises a cylindrical vacuum chamber having a longitudinal axis. Within the vacuum chamber is a containment region. A magnetic field is aligned with the longitudinal axis of the vacuum chamber. The magnetic field is time invariant and uniform in strength over the containment region. An electric field is also aligned with the longitudinal axis of the vacuum chamber and the magnetic field. The electric field is time invariant, and forms a potential well over the containment region. One or more means are disposed around the cloud of particles for inducing a rotating electric field internal to the vacuum chamber. The rotating electric field imparts energy to the charged particles within the containment region and compress the cloud of particles. The means disposed around the outer surface of the vacuum chamber for inducing a rotating electric field are four or more segments forming a segmented ring, the segments conforming to the outer surface of the vacuum chamber. Each of the segments is energized by a separate alternating voltage. The sum of the voltages imposed on each segment establishes the rotating field. When four segments form a ring, the rotating field is obtained by a signal generator applying a sinusoidal signal phase delayed by 90,180 and 270 degrees in sequence to the four segments.

An Analysis of Multiple Configurations of Next-Generation Cathodes in a Low Power Hall Thruster

DTIC Science & Technology

2009-03-01

compressor, the roughing pump , and the cryo-head temperature indicators. Figure 6. SPASS lab vacuum chamber and associated components. To measure...in progress to add additional cryo- pumps to the existing vacuum chamber that may allow higher propellant flow rates without exceeding ~1x10-5 torr... Vacuum Facility .........................................................................................................45 Test Assembly

46 CFR 154.452 - External pressure.

Code of Federal Regulations, 2012 CFR

2012-10-01

...: P1=the vacuum relief valve setting for tanks with a vacuum relief valve, or 24.5 kPa gauge (3.55 psig) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an enclosed... weight of the tank, including corrosion allowance, weight of insulation, weight of dome, weight of pipe...

46 CFR 154.452 - External pressure.

Code of Federal Regulations, 2013 CFR

2013-10-01

...: P1=the vacuum relief valve setting for tanks with a vacuum relief valve, or 24.5 kPa gauge (3.55 psig) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an enclosed... weight of the tank, including corrosion allowance, weight of insulation, weight of dome, weight of pipe...

46 CFR 154.452 - External pressure.

Code of Federal Regulations, 2010 CFR

2010-10-01

...: P1=the vacuum relief valve setting for tanks with a vacuum relief valve, or 24.5 kPa gauge (3.55 psig) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an enclosed... weight of the tank, including corrosion allowance, weight of insulation, weight of dome, weight of pipe...

46 CFR 154.452 - External pressure.

Code of Federal Regulations, 2014 CFR

2014-10-01

...: P1=the vacuum relief valve setting for tanks with a vacuum relief valve, or 24.5 kPa gauge (3.55 psig) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an enclosed... weight of the tank, including corrosion allowance, weight of insulation, weight of dome, weight of pipe...

46 CFR 154.452 - External pressure.

Code of Federal Regulations, 2011 CFR

2011-10-01

...: P1=the vacuum relief valve setting for tanks with a vacuum relief valve, or 24.5 kPa gauge (3.55 psig) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an enclosed... weight of the tank, including corrosion allowance, weight of insulation, weight of dome, weight of pipe...

Preliminary results of sugar maple carbohydrate and growth response under vacuum and gravity sap extraction

Treesearch

Mark L. Isselhardt; Timothy D. Perkins; Abby K. van den Berg; Paul G. Schaberg

2016-01-01

Recent technological advancements have increased the amount of sugar-enriched sap that can be extracted from sugar maple (Acer saccharum). This pilot study quantified overall sugar removal and the impacts of vacuum (60 cm Hg) and gravity sap extraction on residual nonstructural carbohydrate (NSC) concentrations and on stem and twig growth. Vacuum...

21 CFR 155.120 - Canned green beans and canned wax beans.

Code of Federal Regulations, 2010 CFR

2010-04-01

... net weight, and the container is closed under conditions creating a high vacuum in the container. (d... processed by heat, in an appropriate manner before or after being sealed in a container, as to prevent...”. (c) The words “vacuum pack” or “vacuum packed” when the weight of the liquid in the container, as...

Computation of Neutral Gas Flow from a Hall Thruster into a Vacuum Chamber

DTIC Science & Technology

2002-10-18

try to quantify these effects, the direct simulation Monte Carlo method is applied to model a cold flow of xenon gas expanding from a Hall thruster into...a vacuum chamber. The simulations are performed for the P5 Hall thruster operating in a large vacuum tank at the University of Michigan. Comparison

Vacuum Energy and Inflation: 3. Newtonian Cosmology & GR

ERIC Educational Resources Information Center

Huggins, Elisha

2013-01-01

This is paper #3 in a series of four papers on "vacuum energy" and inflation. In paper #1 [see EJ1024183] we discussed an example of what we have been calling vacuum energy. It is an energy with negative pressure whose energy density remains constant in an expanding space. We showed that an energy density with these properties exists…

9 CFR 113.29 - Determination of moisture content in desiccated biological products.

Code of Federal Regulations, 2014 CFR

2014-01-01

... bottles with airtight glass stoppers. (2) Vacuum oven equipped with validated thermometer and thermostat... samples of completed product shall be tested. The weight loss of the sample due to drying in a vacuum oven... labeled sample-weighing bottles with stoppers should be allowed to dry at 60 ±3 °C under vacuum at less...

9 CFR 113.29 - Determination of moisture content in desiccated biological products.

Code of Federal Regulations, 2013 CFR

2013-01-01

... bottles with airtight glass stoppers. (2) Vacuum oven equipped with validated thermometer and thermostat... samples of completed product shall be tested. The weight loss of the sample due to drying in a vacuum oven... labeled sample-weighing bottles with stoppers should be allowed to dry at 60 ±3 °C under vacuum at less...

9 CFR 113.29 - Determination of moisture content in desiccated biological products.

Code of Federal Regulations, 2012 CFR

2012-01-01

... bottles with airtight glass stoppers. (2) Vacuum oven equipped with validated thermometer and thermostat... samples of completed product shall be tested. The weight loss of the sample due to drying in a vacuum oven... labeled sample-weighing bottles with stoppers should be allowed to dry at 60 ±3 °C under vacuum at less...

2016 Summer Series - Jin-Woo Han: Vacuum Electronics in a Nanometer Era

NASA Image and Video Library

2016-06-07

Modern space vehicles rely on transistors. Radiation tolerance of space electronics is critical for space exploration beyond low Earth orbit. NASA Ames Research Center is investigating ways to overcome this issue using vacuums. Dr. Jin-Woo Han's lecture will present advancements in the use of vacuums to improve radiation immunity in space circuitry.

Vacuum Potentials for the Two Only Permanent Free Particles, Proton and Electron. Pair Productions

NASA Astrophysics Data System (ADS)

Zheng-Johansson, J. X.

2012-02-01

The two only species of isolatable, smallest, or unit charges +e and -e present in nature interact with the universal vacuum in a polarisable dielectric representation through two uniquely defined vacuum potential functions. All of the non-composite subatomic particles containing one-unit charges, +e or -e, are therefore formed in terms of the IED model of the respective charges, of zero rest masses, oscillating in either of the two unique vacuum potential fields, together with the radiation waves of their own charges. In this paper we give a first principles treatment of the dynamics of charge in a dielectric vacuum, based on which, combined with solutions for the radiation waves obtained previously, we subsequently derive the vacuum potential function for a given charge q, which we show to be quadratic and consist each of quantised potential levels, giving therefore rise to quantised characteristic oscillation frequencies of the charge and accordingly quantised, sharply-defined masses of the IED particles. By further combining with relevant experimental properties as input information, we determine the IED particles built from the charges +e, -e at their first excited states in the respective vacuum potential wells to be the proton and the electron, the observationally two only stable (permanently lived) and "free" particles containing one-unit charges. Their antiparticles as produced in pair productions can be accordingly determined. The characteristics of all of the other more energetic single-charged non-composite subatomic particles can also be recognised. We finally discuss the energy condition for pair production, which requires two successive energy supplies to (1) first disintegrate the bound pair of vaculeon charges +e, -e composing a vacuuon of the vacuum and (2) impart masses to the disintegrated charges.

Failure of non-vacuum steam sterilization processes for dental handpieces.

PubMed

Winter, S; Smith, A; Lappin, D; McDonagh, G; Kirk, B

2017-12-01

Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8-2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods. All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process. Non-vacuum downward/gravity displacement, type N steam sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

The cost effectiveness of vacuum-assisted versus core-needle versus surgical biopsy of breast lesions.

PubMed

Fernández-García, P; Marco-Doménech, S F; Lizán-Tudela, L; Ibáñez-Gual, M V; Navarro-Ballester, A; Casanovas-Feliu, E

To determine the cost effectiveness of breast biopsy by 9G vacuum-assisted guided by vertical stereotaxy or ultrasonography in comparison with breast biopsy by 14G core-needle biopsy and surgical biopsy. We analyzed a total of 997 biopsies (181 vacuum-assisted, 626 core, and 190 surgical biopsies). We calculated the total costs (indirect and direct) of the three types of biopsy. We did not calculate intangible costs. We measured the percentage of correct diagnoses obtained with each technique. To identify the most cost-effective option, we calculated the mean ratios for the three types of biopsies. Total costs were €225.09 for core biopsy, €638.90 for vacuum-assisted biopsy, and €1780.01 for surgical biopsy. The overall percentage of correct diagnoses was 91.81% for core biopsy, 94.03% for vacuum-assisted biopsy, and 100% for surgical biopsy; however, these differences did not reach statistical significance (p=0.3485). For microcalcifications, the percentage of correct diagnoses was 50% for core biopsy and 96.77% for vacuum-assisted biopsy (p<0.0001). For nodules, there were no significant differences among techniques. The mean cost-effectiveness ratio considering all lesions was 2.45 for core biopsy, 6.79 for vacuum-assisted biopsy, and 17.80 for surgical biopsy. Core biopsy was the dominant option for the diagnosis of suspicious breast lesions in general. However, in cases with microcalcifications, the low percentage of correct diagnoses achieved by core biopsy (50%) advises against its use in this context, where vacuum-assisted biopsy would be the technique of choice because it is more cost-effective than surgical biopsy, the other technique indicated for biopsying microcalcifications. Copyright © 2016 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

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

PubMed

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.

An investigation of the effect of rapid slurry chilling on blown pack spoilage of vacuum-packaged beef primals.

PubMed

Reid, R; Fanning, S; Whyte, P; Kerry, J; Bolton, D

2017-02-01

The aim of this study was to investigate if rapid slurry chilling would retard or prevent blown pack spoilage (BPS) of vacuum-packaged beef primals. Beef primals were inoculated with Clostridium estertheticum subspp. estertheticum (DSMZ 8809), C. estertheticum subspp. laramenise (DSMZ 14864) and C. gasigenes (DSMZ 12272), and vacuum-packaged with and without heat shrinkage (90°C for 3 s). These packs were then subjected to immediate chilling in an ice slurry or using conventional blast chilling systems and stored at 2°C for up to 100 days. The onset and progress of BPS was monitored using the following scale; 0-no gas bubbles in drip; 1-gas bubbles in drip; 2-loss of vacuum; 3-'blown'; 4-presence of sufficient gas inside the packs to produce pack distension and 5-tightly stretched, 'overblown' packs/packs leaking. Rapid slurry chilling (as compared to conventional chilling) did not significantly affect (P > 0.05) the time to the onset or progress of BPS. It was therefore concluded that rapid chilling of vacuum-packaged beef primals, using an ice slurry system, may not be used as a control intervention to prevent or retard blown pack spoilage. This study adds to our growing understanding of blown pack spoilage of vacuum-packaged beef primals and suggests that rapid chilling of vacuum-packaged beef primals is not a control option for the beef industry. The results suggest that neither eliminating the heat shrinkage step nor rapid chilling of vacuum-packaged beef retard the time to blown pack spoilage. © 2016 The Society for Applied Microbiology.

Short communication: Effects of vacuum freeze-drying on inactivation of Cronobacter sakazakii ATCC29544 in liquid media with different initial inoculum levels.

PubMed

Jiao, Rui; Gao, Jina; Zhang, Xiyan; Zhang, Maofeng; Chen, Jiren; Wu, Qingping; Zhang, Jumei; Ye, Yingwang

2017-03-01

Vacuum freeze-drying is an important food-processing technology for valid retention of nutrients and bioactive compounds. Cronobacter sakazakii has been reported to be associated with severe infections in neonates through consumption of contaminated powdered infant formula. In this study, effects of vacuum freeze-drying treatment for 12, 24, and 36 h on inactivation of C. sakazakii with different initial inoculum levels in sterile water, tryptic soy broth (TSB), skim milk, and whole milk were determined. Results indicated that the lethality rate of C. sakazakii in each sample increased with the extension of vacuum freeze-drying time. With initial inoculum levels of 10 2 and 10 3 cfu/mL, the survival of C. sakazakii in different liquid media was significantly affected by vacuum freeze-drying for 12, 24, and 36 h. In addition, the lethality rates of C. sakazakii in whole milk, skim milk, and TSB was significantly reduced compared with those in sterile water. Furthermore, whole milk showed the strongest protective role for C. sakazakii cells, followed by skim milk and TSB medium. Using the scanning electron microscope, the intracellular damage and obvious distortion of C. sakazakii cells were observed after vacuum freeze-drying for 24 and 36 h compared with the untreated sample, and the injured cells increased with the extension of vacuum-drying time. We concluded that inactivation of vacuum freeze-drying on C. sakazakii cells is related to the food matrix, and a combination with other methods for inactivating C. sakazakii is required for ensuring microbial safety of powdered infant formula. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

[Vacuum-assisted therapy for various wound types including diabetic foot ulcer].

PubMed

Farah, Raymond; Gantus, Maher; Kogan, Leonid

2011-03-01

Vacuum is a noninvasive system that creates a localized controlled negative pressure environment. In this study, vacuum was provided by the V.A.C. Therapy system, which promotes wound healing by delayed primary or secondary intention through creating a moist wound environment, preparing the wound bed for closure, reducing edema, and promoting formation and perfusion of granulation tissue. Vacuum-assisted closure therapy is indicated for use in all care settings and for a variety of wound types including diabetic foot ulcers. The purpose of this study was to evaluate safety and clinical efficacy of negative pressure wound therapy (NPWT) compared with advanced moist wound therapy and standard treatment to treat foot ulcers in diabetic patients. This trial enrolled 43 patients; most of them were diabetic patients at any age with various skin ulcers and diabetic foot. These patients were divided into two groups, 17 patients were treated with vacuum and the 26 patients in the control group were treated with standard therapy including debridement. A greater proportion of foot and skin ulcers achieved complete ulcer closure with vacuum-assisted therapy p<0.001 compared with the standard therapy. Vacuum therapy significantly decreased the duration and frequency of admission p=0.032 and decreased the rate of amputation p<0.001. Results of our trial support other studies and demonstrate that vacuum is as safe as and more efficacious than standard therapy in the treatment of diabetic foot ulcers. A significantly greater number of patients achieved complete ulcer closure and granulation tissue formation with this therapy. The study group showed a significant reduction in the median time needed to heal ulcers, reduction of the number of admissions and amputation frequency.

Ultrasound-Guided Core-Needle Versus Vacuum-Assisted Breast Biopsy: A Cost Analysis Based on the American Society of Breast Surgeons' Mastery of Breast Surgery Registry.

PubMed

Grady, Ian; Vasquez, Tony; Tawfik, Sara; Grady, Sean

2017-03-01

To evaluate the cost-efficacy of vacuum-assisted ultrasound-guided breast biopsy instruments compared to ultrasound-guided 14-gauge spring-loaded core-needle biopsy. The American Society of Breast Surgeons' Mastery of Breast Surgery Registry was reviewed. Biopsy findings, any rebiopsy, and the instrument used were abstracted for 31,451 ultrasound-guided biopsy procedures performed between 2001 and July 2014. Rates of cancer diagnosis and rebiopsy were calculated for each instrument. A linear mathematical model was developed to calculate total cost per cancer diagnosis, including procedural costs and the costs of any additional surgical rebiopsy procedures. Mean cost per cancer diagnosis with confidence limits was then determined for 14-gauge spring-loaded core-needle biopsy and 14 different vacuum-assisted instruments. For 14-gauge spring-loaded core-needle biopsy, mean cost per cancer diagnosis was $4346 (4327-$4366). For the vacuum-assisted instruments, mean cost per cancer diagnosis ranged from a low of $3742 ($3732-$3752) to a high of $4779 ($4750-$4809). Vacuum-assisted instruments overall were more cost-effective than core with a mean cost per cancer diagnosis of $4052 ($4038-$4067) (p < 0.05). Tethered vacuum-assisted instruments performed best with a mean cost per cancer diagnosis of $3978 ($3964-$3991) (p < 0.05). Nontethered devices had a mean cost per cancer diagnosis of $4369 ($4350-$4388), a result no better than core (p < 0.05). Ultrasound-guided vacuum-assisted breast biopsy had a lower mean cost per cancer diagnosis than 14-gauge spring-loaded core-needle biopsy. This advantage was only seen in tethered vacuum-assisted instruments. Within device families, larger instruments tended to outperform smaller instruments.

Microbial effect of steam vacuum pasteurisation implemented after slaughtering and dressing of sheep and lamb.

PubMed

Hassan, Ammar Ali; Skjerve, Eystein; Bergh, Claus; Nesbakken, Truls

2015-01-01

The main objective of the study was to assess the effect of steam vacuum pasteurisation on carcass contamination with focus on Escherichia coli, Enterobacteriaceae and total plate count (TPC). Additionally, the effect of an additional tryptone soy agar (TSA) step for resuscitation of Enterobacteriaceae after steam vacuum pasteurisation was investigated. Steam vacuum pasteurisation was applied at a temperature of >82°C for a duration of 10s on sheep and lamb carcasses (n=120). Samples were taken immediately: i) after trimming just before the use of steam vacuum and ii) after use of steam vacuum. Nordic Committee on Food Analysis methods were used in microbial analyses. The differences in log reduction were found significant for all of the three microorganisms (p<0.05). For TPC, the general reduction was a 0.65 log10 in the number of colony forming units (CFU) per cm(2). For E. coli, the median reduction effect on carcasses positive before decontamination was 1.1 log10 CFU/cm(2). A large variability of the effect was however found, with 50% of the figures ranging from a 0.24 to 1.62 log10 CFU/cm(2) reduction and a 10-90% range of 0-2.1. The number of positive carcasses with Enterobacteriaceae after steam vacuum pasteurisation was higher in samples where TSA+violet red bile glucose agar (VRBGA) was used compared to samples where only VRBGA was used (p<0.01). Steam vacuum pasteurisation was found efficient in reducing the total count, read as TPC, as well as the level of E. coli and Enterobacteriaceae. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pseudo ribbon metal ion beam source.

PubMed

Stepanov, Igor B; Ryabchikov, Alexander I; Sivin, Denis O; Verigin, Dan A

2014-02-01

The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

Multivariate Analysis of Fruit Antioxidant Activities of Blackberry Treated with 1-Methylcyclopropene or Vacuum Precooling

PubMed Central

Li, Jian; Ma, Guowei; Ma, Lin; Bao, Xiaolin; Li, Liping; Zhao, Qian

2018-01-01

Effects of 1-methylcyclopropene (1-MCP) and vacuum precooling on quality and antioxidant properties of blackberries (Rubus spp.) were evaluated using one-way analysis of variance, principal component analysis (PCA), partial least squares (PLS), and path analysis. Results showed that the activities of antioxidant enzymes were enhanced by both 1-MCP treatment and vacuum precooling. PCA could discriminate 1-MCP treated fruit and the vacuum precooled fruit and showed that the radical-scavenging activities in vacuum precooled fruit were higher than those in 1-MCP treated fruit. The scores of PCA showed that H2O2 content was the most important variables of blackberry fruit. PLSR results showed that peroxidase (POD) activity negatively correlated with H2O2 content. The results of path coefficient analysis indicated that glutathione (GSH) also had an indirect effect on H2O2 content. PMID:29487622

REVIEWS OF TOPICAL PROBLEMS: Cosmic vacuum

NASA Astrophysics Data System (ADS)

Chernin, Artur D.

2001-11-01

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

Two year operational experience with the TPS vacuum system

NASA Astrophysics Data System (ADS)

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.

Superconducting Vacuum-Gap Crossovers for High Performance Microwave Applications

NASA Technical Reports Server (NTRS)

Denis, Kevin L.; Brown, Ari D.; Chang, Meng-Ping; Hu, Ron; U-Yen, Kongpop; Wollack, Edward J.

2016-01-01

The design and fabrication of low-loss wide-bandwidth superconducting vacuum-gap crossovers for high performance millimeter wave applications are described. In order to reduce ohmic and parasitic losses at millimeter wavelengths a vacuum gap is preferred relative to dielectric spacer. Here, vacuum-gap crossovers were realized by using a sacrificial polymer layer followed by niobium sputter deposition optimized for coating coverage over an underlying niobium signal layer. Both coplanar waveguide and microstrip crossover topologies have been explored in detail. The resulting fabrication process is compatible with a bulk micro-machining process for realizing waveguide coupled detectors, which includes sacrificial wax bonding, and wafer backside deep reactive ion etching for creation of leg isolated silicon membrane structures. Release of the vacuum gap structures along with the wax bonded wafer after DRIE is implemented in the same process step used to complete the detector fabrication. ?

Vacuum birefringence detection in all-optical scenarios

NASA Astrophysics Data System (ADS)

Ataman, Stefan

2018-06-01

In this paper we propose an all-optical vacuum birefringence experiment and evaluate its feasibility for various scenarios. Many petawatt-class lasers became operational and many more are expected to enter operation in the near future, therefore unprecedented electromagnetic fields (EL˜1014-1015 V/m and intensities IL˜1021-1023W/cm 2 ) will become available for experiments. In our proposal a petawatt-class laser disturbs the quantum vacuum and creates a delay in a counterpropagating probe laser beam. Placing this delayed beam in one arm of a Mach-Zehnder interferometer (MZI), allows the measurement of the vacuum refraction coefficient via a phase shift. Coherent as well as squeezed light are both considered and the minimum phase sensitivity evaluated. We show that using existing technology with some moderately optimistic assumptions, at least part of the discussed scenarios are feasible for a vacuum birefringence detection experiment.

Source replenishment device for vacuum deposition

DOEpatents

Hill, Ronald A.

1988-01-01

A material source replenishment device for use with a vacuum deposition apparatus. The source replenishment device comprises an intermittent motion producing gear arrangement disposed within the vacuum deposition chamber. An elongated rod having one end operably connected to the gearing arrangement is provided with a multiarmed head at the opposite end disposed adjacent the heating element of the vacuum deposition apparatus. An inverted U-shaped source material element is releasably attached to the outer end of each arm member whereby said multiarmed head is moved to locate a first of said material elements above said heating element, whereupon said multiarmed head is lowered to engage said material element with the heating element and further lowered to release said material element on the heating element. After vaporization of said material element, second and subsequent material elements may be provided to the heating element without the need for opening the vacuum deposition apparatus to the atmosphere.

Source replenishment device for vacuum deposition

DOEpatents

Hill, R.A.

1986-05-15

A material source replenishment device for use with a vacuum deposition apparatus is described. The source replenishment device comprises an intermittent motion producing gear arrangement disposed within the vacuum deposition chamber. An elongated rod having one end operably connected to the gearing arrangement is provided with a multiarmed head at the opposite end disposed adjacent the heating element of the vacuum deposition apparatus. An inverted U-shaped source material element is releasably attached to the outer end of each arm member whereby said multiarmed head is moved to locate a first of said material elements above said heating element, whereupon said multiarmed head is lowered to engage said material element with the heating element and further lowered to release said material element on the heating element. After vaporization of said material element, second and subsequent material elements may be provided to the heating element without the need for opening the vacuum deposition apparatus to the atmosphere.

Electric Propulsion Laboratory Vacuum Chamber

NASA Image and Video Library

1964-06-21

Engineer Paul Reader and his colleagues take environmental measurements during testing of a 20-inch diameter ion engine in a vacuum tank at the Electric Propulsion Laboratory (EPL). Researchers at the Lewis Research Center were investigating the use of a permanent-magnet circuit to create the magnetic field required power electron bombardment ion engines. Typical ion engines use a solenoid coil to create this magnetic field. It was thought that the substitution of a permanent magnet would create a comparable magnetic field with a lower weight. Testing of the magnet system in the EPL vacuum tanks revealed no significant operational problems. Reader found the weight of the two systems was similar, but that the thruster’s efficiency increased with the magnet. The EPL contained a series of large vacuum tanks that could be used to simulate conditions in space. Large vacuum pumps reduced the internal air pressure, and a refrigeration system created the cryogenic temperatures found in space.

Preparation of W/CuCrZr mono-block test mock-up using vacuum brazing technique

NASA Astrophysics Data System (ADS)

Premjit Singh, K.; Khirwadkar, S.; Bhope, Kedar; Patel, Nikunj; Mokaria, Prakash

2017-04-01

Development of the joining for W/CuCrZr mono-block PFC test mock-up is an interesting area in Fusion R&D. W/Cu bimetallic material has been prepared using OFHC Copper casting approach on the radial surface of W mono-block tile surface. The W/Cu bimetallic material has been joined with CuCrZr tube (heat sink) material with the vacuum brazing route. Vacuum brazing of W/Cu-CuCrZr has been performed @ 970°C for 10 min using NiCuMn-37 filler material under deep vacuum environment (10-6 mbar). Graphite fixture was used for OFHC Copper casting and vacuum brazing experiments. The joint integrity of W/Cu-CuCrZr mono-block mock-up of W/Cu and Cu-CuCrZr interface has been checked using ultrasonic immersion technique. The result of the experimental work is presented in the paper.

Vacuum-insulated catalytic converter

DOEpatents

Benson, David K.

2001-01-01

A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

Vacuum and low oxygen pressure influence on BaFe12O19 film deposited by pulse laser deposition

NASA Astrophysics Data System (ADS)

Kumar, Pawan; Gaur, Anurag; Choudhary, R. J.

2018-05-01

BaFe12O19 hexaferrite thin films are deposited on Si (111) substrate by the pulse laser deposition (PLD) technique in high vacuum 10-6 Torr and low oxygen pressure (10 mTorr) at 650°C substrate temperature. The effects of high vacuum and low pressure on magnetic and optical properties are studied. These films are characterized by the x-ray diffractometer (XRD), SQUID-VSM magnetometer, and Photo-luminescence spectroscopy. XRD pattern reveals that the BaFe12O19 film well formed in both environments without any impurity pick. High magnetic saturazation 317 emu/cm3 and coercivity 130 Oe are observed for the film deposited in vacuum. Photoluminescence emission spectrum of BaFe12O19 film reveals that the higher intensity emission peak at ˜372 nm under the excitation wavelength of 270 nm is observed for the film grown in vacuum.

Complex technology of vacuum-arc processing of structural material surface

NASA Astrophysics Data System (ADS)

Arustamov, V. N.; Ashurov, Kh. B.; Kadyrov, Kh. Kh.; Khudoikulov, I. Kh.

2015-08-01

The development of environmentally friendly and energy-resource-saving technologies based on vacuum arc discharge is a topical problem in science and engineering. In view of their unique properties, cathode spots of a vacuum arc induce cleaning of the surface of an article (cathode) from various contaminations and pulsed thermal action on the surface layers. These processes occur in complex with vacuum-arc deposition of coatings in the same technological cycle, which makes it possible to considerably increase the efficiency of methods for changing physical, mechanical, and chemical properties of the surface of steel articles, which considerably increase their service life. Analysis of the formation of the temperature regime of the surface during vacuum arc action and of the parameters of the deposited coating will make it possible to optimize the regimes of complex treatment of the surfaces of articles and is of considerable theoretical and practical importance.

Cold-welding test environment

NASA Technical Reports Server (NTRS)

Wang, J. T.

1972-01-01

A flight test was conducted and compared with ground test data. Sixteen typical spacecraft material couples were mounted on an experimental research satellite in which a motor intermittently drove the spherical moving specimens across the faces of the fixed flat specimens in an oscillating motion. Friction coefficients were measured over a period of 14-month orbital time. Surface-to-surface sliding was found to be the controlling factor of generating friction in a vacuum environment. Friction appears to be independent of passive vacuum exposure time. Prelaunch and postlaunch tests identical to the flight test were performed in an oil-diffusion-pumped ultrahigh vacuum chamber. Only 50% of the resultant data agreed with the flight data owing to pump oil contamination. Identical ground tests were run in an ultrahigh vacuum facility and a ion-pumped vacuum chamber. The agreement (90%) between data from these tests and flight data established the adequacy of these test environments and facilities.

Improvement of an Atomic Clock using Squeezed Vacuum

NASA Astrophysics Data System (ADS)

Kruse, I.; Lange, K.; Peise, J.; Lücke, B.; Pezzè, L.; Arlt, J.; Ertmer, W.; Lisdat, C.; Santos, L.; Smerzi, A.; Klempt, C.

2016-09-01

Since the pioneering work of Ramsey, atom interferometers are employed for precision metrology, in particular to measure time and to realize the second. In a classical interferometer, an ensemble of atoms is prepared in one of the two input states, whereas the second one is left empty. In this case, the vacuum noise restricts the precision of the interferometer to the standard quantum limit (SQL). Here, we propose and experimentally demonstrate a novel clock configuration that surpasses the SQL by squeezing the vacuum in the empty input state. We create a squeezed vacuum state containing an average of 0.75 atoms to improve the clock sensitivity of 10000 atoms by 2.05-0.37 +0 .34 dB . The SQL poses a significant limitation for today's microwave fountain clocks, which serve as the main time reference. We evaluate the major technical limitations and challenges for devising a next generation of fountain clocks based on atomic squeezed vacuum.

National Synchrotron Light Source II storage ring vacuum systems

DOE PAGES

Hseuh, Hsiao-Chaun; Hetzel, Charles; Leng, Shuwei; ...

2016-04-05

The National Synchrotron Light Source II, completed in 2014, is a 3-GeV synchrotron radiation (SR) facility at Brookhaven National Laboratory and has been in steady operation since. With a design electron current of 500 mA and subnanometer radians horizontal emittance, this 792-m circumference storage ring is providing the highest flux and brightness x-ray beam for SR users. Also, the majority of the storage ring vacuum chambers are made of extruded aluminium. Chamber sections are interconnected using low-impedance radiofrequency shielded bellows. SR from the bending magnets is intercepted by water-cooled compact photon absorbers resided in the storage ring chambers. Finally, thismore » paper presents the design of the storage ring vacuum system, the fabrication of vacuum chambers and other hardware, the installation, the commissioning, and the continuing beam conditioning of the vacuum systems.« less

Design and fabrication of the vacuum systems for TPS pulsed septum magnets

NASA Astrophysics Data System (ADS)

Chan, C. K.; Chang, C. C.; Chen, C. L.; Yang, C. S.; Chen, C. S.; Lin, F. Y.; Chen, J. R.

2014-11-01

Three in-air pulsed septum magnets were developed to inject and extract electron beams for the 3 GeV synchrotron facility, the Taiwan Photon Source (TPS). The vacuum chamber is a novel combined aluminium-stainless steel design, using a bimetallic flange to connect the two material types. To evaluate the vacuum performances of these vacuum chambers, we set up a test bench at which we simultaneously measure the rates of thermal outgassing of the aluminium chamber and the septum tube with a throughput method. The test result indicates that the rate q72 of thermal outgassing measured after 1 day from baking at 150 °C was 1×10-13 mbar L s-1 cm-2. The magnetic leakage measurements show the combination of conductor slitting, magnetic shielding and the aluminium vacuum chamber reduce the peak value of the leakage field integral to ~10 G cm along the trajectory of the stored beam.

Alaskan refiner raced against winter to relocate vacuum unit

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

Gdula, L.M.; Wentworth, J.A.

In late November 1994, San Antonio-based Tesoro Petroleum Corp. and Litwin Engineers and Constructors Inc. completed the relocation and refurbishment of a $25 million vacuum unit at Tesoro`s 72,000 b/d Kenai refinery. The addition of the vacuum distillation unit is a critical component in Tesoro`s market-driven strategy to enhance operating profits by maximizing production of higher-margin products such as gasoline and jet fuel. With its new vacuum distillation unit, Tesoro has reduced production of lower-value residual fuel oil while recovering more lighter, high-value material. The paper discusses the economic and strategic merits of purchasing and relocating an existing vacuum unit,more » the project schedule, new equipment, dismantling and transport, installation, tie-ins and start-up, products, operating changes, corrosion concerns, off gas, steam generation, design changes, environmental issues, reporting requirements, and accomplishments.« less

Opto-mechanical design of vacuum laser resonator for the OSQAR experiment

NASA Astrophysics Data System (ADS)

Hošek, Jan; Macúchová, Karolina; Nemcová, Šárka; Kunc, Štěpán.; Šulc, Miroslav

2015-01-01

This paper gives short overview of laser-based experiment OSQAR at CERN which is focused on search of axions and axion-like particles. The OSQAR experiment uses two experimental methods for axion search - measurement of the ultra-fine vacuum magnetic birefringence and a method based on the "Light shining through the wall" experiment. Because both experimental methods have reached its attainable limits of sensitivity we have focused on designing a vacuum laser resonator. The resonator will increase the number of convertible photons and their endurance time within the magnetic field. This paper presents an opto-mechanical design of a two component transportable vacuum laser resonator. Developed optical resonator mechanical design allows to be used as a 0.8 meter long prototype laser resonator for laboratory testing and after transportation and replacement of the mirrors it can be mounted on the LHC magnet in CERN to form a 20 meter long vacuum laser resonator.

Solid-state acquisition of fingermark topology using dense columnar thin films.

PubMed

Lakhtakia, Akhlesh; Shaler, Robert C; Martín-Palma, Raúl J; Motyka, Michael A; Pulsifer, Drew P

2011-05-01

Various vacuum techniques are employed to develop fingermarks on evidentiary items. In this work, a vacuum was used to deposit columnar thin films (CTFs) on untreated, cyanoacrylate-fumed or dusted fingermarks on a limited selection of nonporous surfaces (microscope glass slides and evidence tape). CTF deposition was not attempted on fingermarks deposited on porous surfaces. The fingermarks were placed in a vacuum chamber with the fingermark side facing an evaporating source boat containing either chalcogenide glass or MgF(2). Thermal evaporation of chalcogenide glass or MgF(2) under a 1 μTorr vacuum for 30 min formed dense CTFs on fingermark ridges, capturing the topographical features. The results show that it is possible to capture fingermark topology using CTFs on selected untreated, vacuumed cyanoacrylate-fumed or black powder-dusted nonporous surfaces. Additionally, the results suggested this might be a mechanism to help elucidate the sequence of deposition. © 2011 American Academy of Forensic Sciences.

Solid Lubrication by Multiwalled Carbon Nanotubes in Air and in Vacuum for Space and Aeronautics Applications

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa; Street, Kenneth W., Jr.; Andraws, Rodney; Jacques, David; VanderWal, Randy L.; Sayir, Ali

2005-01-01

To evaluate recently developed aligned multiwalled carbon nanotubes (MWNTs) and dispersed MWNTs for solid lubrication applications, unidirectional sliding friction experiments were conducted with 440 C stainless steel balls and hemispherical alumina-yttria stabilized zirconia pins in sliding contact with the MWNTs deposited on quartz disks in air and in vacuum. The results indicate that MWNTs have superior solid lubrication friction properties and endurance lives in air and vacuum under dry conditions. The coefficient of friction of the dispersed MWNTs is close to 0.05 and 0.009 in air and in vacuum, respectively, showing good dry lubricating ability. The wear life of MWNTs exceeds 1 million passes in both air and vacuum showing good durability. In general, the low coefficient of friction can be attributed to the combination of the transferred, agglomerated patches of MWNTs on the counterpart ball or pin surfaces and the presence of tubular MWNTs at interfaces.

Vapor-barrier Vacuum Isolation System

NASA Technical Reports Server (NTRS)

Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

2014-01-01

A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

Mechanical properties and production quality of hand-layup and vacuum infusion processed hybrid composite materials for GFRP marine structures

NASA Astrophysics Data System (ADS)

Kim, Sang-Young; Shim, Chun Sik; Sturtevant, Caleb; Kim, Dave (Dae-Wook); Song, Ha Cheol

2014-09-01

Glass Fiber Reinforced Plastic (GFRP) structures are primarily manufactured using hand lay-up or vacuum infusion techniques, which are cost-effective for the construction of marine vessels. This paper aims to investigate the mechanical properties and failure mechanisms of the hybrid GFRP composites, formed by applying the hand lay-up processed exterior and the vacuum infusion processed interior layups, providing benefits for structural performance and ease of manufacturing. The hybrid GFRP composites contain one, two, and three vacuum infusion processed layer sets with consistent sets of hand lay-up processed layers. Mechanical properties assessed in this study include tensile, compressive and in-plane shear properties. Hybrid composites with three sets of vacuum infusion layers showed the highest tensile mechanical properties while those with two sets had the highest mechanical properties in compression. The batch homogeneity, for the GFRP fabrication processes, is evaluated using the experimentally obtained mechanical properties

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, G.T.; Jackson, J.W.

1990-03-19

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, Gordon T.; Jackson, John W.

1991-01-01

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Triviality of entanglement entropy in the Galilean vacuum

NASA Astrophysics Data System (ADS)

Hason, Itamar

2018-05-01

We study the entanglement entropy of the vacuum in non-relativistic local theories with Galilean or Schrödinger symmetry. We clear some confusion in the literature on the free Schrödinger case. We find that with only positive U (1) charge particles (states) and a unique zero U (1) charge state (the vacuum) the entanglement entropy must vanish in that state.

Vacuum aperture isolator for retroreflection from laser-irradiated target

DOEpatents

Benjamin, Robert F.; Mitchell, Kenneth B.

1980-01-01

The disclosure is directed to a vacuum aperture isolator for retroreflection of a laser-irradiated target. Within a vacuum chamber are disposed a beam focusing element, a disc having an aperture and a recollimating element. The edge of the focused beam impinges on the edge of the aperture to produce a plasma which refracts any retroreflected light from the laser's target.

Container Prevents Oxidation Of Metal Powder

NASA Technical Reports Server (NTRS)

Woodford, William H.; Power, Christopher A.; Mckechnie, Timothy N.; Burns, David H.

1992-01-01

Sealed high-vacuum container holds metal powder required free of contamination by oxygen from point of manufacture to point of use at vacuum-plasma-spraying machine. Container protects powder from air during filling, storage, and loading of spraying machine. Eliminates unnecessary handling and transfer of powder from one container to another. Stainless-steel container sits on powder feeder of vacuum-plasma-spraying machine.

Lightweight evacuated multilayer insulation systems for the space shuttle vehicle

NASA Technical Reports Server (NTRS)

Barclay, D. L.; Bell, J. E.; Zimmerman, D. K.

1973-01-01

The elements in the evacuated multilayer insulation system were investigated, and the major weight contributors for optimization selected. Outgassing tests were conducted on candidate vacuum jacket materials and experiments were conducted to determine the vacuum and structural integrity of selected vacuum jacket configurations. A nondestructive proof test method, applicable to externally pressurized shells, was validated on this program.

The proposal of recommendations for the operation of vacuum sewerage

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Maple sugaring with vacuum pumping during the fall season

Treesearch

H. Clay Smith; Alan G., Jr. Snow

1971-01-01

Vacuum pumping of sugar maple trees during the late fall and early winter months is not advisable in northern Vermont. However, fall pumping may be profitable in other areas of the sugar maple range. It is recommended that the weather pattern in a given locale be observed; and if conditions are favorable, vacuum pumping should be tried on a small scale before...