Compressed Air/Vacuum Transportation Techniques

Science.gov (United States)

Guha, Shyamal

2011-03-01

General theory of compressed air/vacuum transportation will be presented. In this transportation, a vehicle (such as an automobile or a rail car) is powered either by compressed air or by air at near vacuum pressure. Four version of such transportation is feasible. In all versions, a ``c-shaped'' plastic or ceramic pipe lies buried a few inches under the ground surface. This pipe carries compressed air or air at near vacuum pressure. In type I transportation, a vehicle draws compressed air (or vacuum) from this buried pipe. Using turbine or reciprocating air cylinder, mechanical power is generated from compressed air (or from vacuum). This mechanical power transferred to the wheels of an automobile (or a rail car) drives the vehicle. In type II-IV transportation techniques, a horizontal force is generated inside the plastic (or ceramic) pipe. A set of vertical and horizontal steel bars is used to transmit this force to the automobile on the road (or to a rail car on rail track). The proposed transportation system has following merits: virtually accident free; highly energy efficient; pollution free and it will not contribute to carbon dioxide emission. Some developmental work on this transportation will be needed before it can be used by the traveling public. The entire transportation system could be computer controlled.

High Vacuum Techniques for Anionic Polymerization

KAUST Repository

Ratkanthwar, Kedar; Hadjichristidis, Nikolaos; Mays, Jimmy

2015-01-01

Anionic polymerization high vacuum techniques (HVTs) are the most suitable for the preparation of polymer samples with well-defined complex macromolecular architectures. Though HVTs require glassblowing skill for designing and making polymerization

Vacuum leak test technique of JT-60

International Nuclear Information System (INIS)

Kaminaga, Atsushi; Arai, Takashi; Kodama, Kozo; Sasaki, Noboru; Saidoh, Masahiro

1998-01-01

Since a vacuum vessel of JT-60 is very large (167 m 3 ) and is combined with many components, such as magnetic coils, neutral beam injection systems and RF heating systems, etc., the position of leak testing exceeds 700. The two kind of techniques for vacuum leak test used in JT-60 has been described. Firstly the probe helium gas can be fed remotely in the three-dimensionally sectioned 54 regions of the JT-60 torus. The leak test was very rapidly performed by using this method. Secondly the helium detector system has been modified by the additional installation of the cryopump, which reduced the background level of the deuterium gas. The sensitivity of vacuum leak test with the cryopump was two orders of magnitude larger than that of without it. The examples of the performed vacuum leak test are stated. The vacuum leaks during experiments were 9 times. They were caused by thermal strain and plasma discharge. The vacuum leaks just after maintenance are 36 times which mainly caused by mis-installation. (author)

Instant Sublime Text starter

CERN Document Server

Haughee, Eric

2013-01-01

A starter which teaches the basic tasks to be performed with Sublime Text with the necessary practical examples and screenshots. This book requires only basic knowledge of the Internet and basic familiarity with any one of the three major operating systems, Windows, Linux, or Mac OS X. However, as Sublime Text 2 is primarily a text editor for writing software, many of the topics discussed will be specifically relevant to software development. That being said, the Sublime Text 2 Starter is also suitable for someone without a programming background who may be looking to learn one of the tools of

Thermionic vacuum arc (TVA) technique for magnesium thin film deposition

Energy Technology Data Exchange (ETDEWEB)

Balbag, M.Z., E-mail: zbalbag@ogu.edu.t [Eskisehir Osmangazi University, Education Faculty, Primary Education, Meselik Campus, Eskisehir 26480 (Turkey); Pat, S.; Ozkan, M.; Ekem, N. [Eskisehir Osmangazi University, Art and Science Faculty, Physics Department, Eskisehir 26480 (Turkey); Musa, G. [Ovidius University, Physics Department, Constanta (Romania)

2010-08-15

In this study, magnesium thin films were deposited on glass substrate by the Thermionic Vacuum Arc (TVA) technique for the first time. We present a different technique for deposition of high-quality magnesium thin films. By means of this technique, the production of films is achieved by condensing the plasma of anode material generated using Thermionic Vacuum Arc (TVA) under high vacuum conditions onto the surface to be coated. The crystal orientation and morphology of the deposited films were investigated by using XRD, EDX, SEM and AFM. The aim of this study is to search the use of TVA technique to coat magnesium thin films and to determine some of the physical properties of the films generated. Furthermore, this study will contribute to the scientific studies which search the thin films of magnesium or the compounds containing magnesium. In future, this study will be preliminary work to entirely produce magnesium diboride (MgB{sub 2}) superconductor thin film with the TVA technique.

Enthalpies of sublimation of fullerenes by thermogravimetry

Energy Technology Data Exchange (ETDEWEB)

Martínez-Herrera, Melchor; Campos, Myriam; Torres, Luis Alfonso; Rojas, Aarón, E-mail: arojas@cinvestav.mx

2015-12-20

Graphical abstract: - Highlights: • Enthalpies of sublimation of fullerenes were measured by thermogravimetry. • Results of enthalpies of sublimation are comparable with data reported in literature. • Not previously reported enthalpy of sublimation of C{sub 78} is supplied in this work. • Enthalpies of sublimation show a strong dependence with the number of carbon atoms in the cluster. • Enthalpies of sublimation are congruent with dispersion forces ruling cohesion of solid fullerene. - Abstract: The enthalpies of sublimation of fullerenes, as measured in the interval of 810–1170 K by thermogravimetry and applying the Langmuir equation, are reported. The detailed experimental procedure and its application to fullerenes C{sub 60}, C{sub 70}, C{sub 76}, C{sub 78} and C{sub 84} are supplied. The accuracy and uncertainty associated with the experimental results of the enthalpy of sublimation of these fullerenes show that the reliability of the measurements is comparable to that of other indirect high-temperature methods. The results also indicate that the enthalpy of sublimation increases proportionally to the number of carbon atoms in the cluster but there is also a strong correlation between the enthalpy of sublimation and the polarizability of each fullerene.

DEVELOPMENT OF VACUUM SUBLIMATION DRYERS USING THERMOELECTRIC MODULES

Directory of Open Access Journals (Sweden)

R. A. Barykin

2014-01-01

Full Text Available Summary. The main directions of use of freeze-dryed products and ingredients are revealed. The analysis of sales markets of freeze-dryed products is provided. It is shown that introduction of innovative production technologies will allow to develop dynamically not only to the large companies, but also small firms that will create prerequisites for growth of the Russian market of freeze-dryed products. Tendencies of development of the freeze-drying equipment are analysed. Relevance of development of energy saving freeze-dryers is proved The integrated approach to creation of competitive domestic technologies and the equipment for sublimation dehydration of thermolabile products consists in use of the effective combined remedies of a power supply, a process intensification, reduction of specific energy consumption and, as a result, decrease in product cost at achievement of high quality indicators. Advantages of thermoelectric modules as alternative direction to existing vapor-compression and absorbing refrigerating appliances are given. Researches of process of freeze-drying dehydration with use of thermoelectric modules are conducted. It is scientifically confirmed, that the thermoelectric module working at Peltier effect, promotes increase in refrigerating capacity due to use of the principle of the thermal pump. Options of use of thermoelectric modules in designs of dryers are offered. Optimum operating modes and number of modules in section are defined. Ways of increase of power efficiency of freeze-dryers with use of thermoelectric modules are specified. The received results will allow to make engineering calculations and design of progressive freeze-drying installations with various ways of a power supply.

The Sublime in churches and mosques

NARCIS (Netherlands)

Doudouh, N.; van Ginderen, S.

2012-01-01

Fear gives us the ability to experience the sublime in various situations when we talk about the sublime in architecture.According to Edmund Burke what causes this fear on a person, is darkness and vastness. Can it be that places of worship have been built for the purpose of expressing the sublime?

Sublime science: Teaching for scientific sublime experiences in middle school classrooms

Science.gov (United States)

Cavanaugh, Shane

Due to a historical separation of cognition and emotion, the affective aspects of learning are often seen as trivial in comparison to the more 'essential' cognitive qualities - particularly in the domain of science. As a result of this disconnect, feelings of awe, wonder, and astonishment as well as appreciation have been largely ignored in the working lives of scientists. In turn, I believe that science education has not accurately portrayed the world of science to our students. In an effort to bring the affective qualities of science into the science classroom, I have drawn on past research in the field of aesthetic science teaching and learning as well as works by, Burke, Kant, and Dewey to explore a new construct I have called the "scientific sublime". Scientific sublime experiences represent a sophisticated treatment of the cognitive as well as affective qualities of science learning. The scientific sublime represents feelings of awe, wonder, and appreciation that come from a deep understanding. It is only through this understanding of a phenomenon that we can appreciate its true complexity and intricacies, and these understandings when mixed with the emotions of awe and reverence, are sublime. Scientific sublime experiences are an attempt at the re-integration of cognition and feeling. The goal of this research was twofold: to create and teach a curriculum that fosters scientific sublime experiences in middle school science classes, and to better understand how these experiences are manifested in students. In order to create an approach to teaching for scientific sublime experiences, it was first necessary for me to identify key characteristics of such an experience and a then to create a pedagogical approach, both of which are described in detail in the dissertation. This research was conducted as two studies in two different middle schools. My pedagogical approach was used to create and teach two five-week 7 th grade science units---one on weather

Por uma metafísica do sublime

Directory of Open Access Journals (Sweden)

Martha de Almeida

2009-12-01

Full Text Available The sublime has been analyzed since ancient times with a striking compared with tragedy, whether as a literary genre, whether through Poetics, Aristotle's catharsis we translate the feeling the sublime. In modernity, new names were coming to work with this theory: Hume himself, in his essay The Tragedy, was impressed by the ability of this art form has to produce such strong effects on the viewer. But who else has strengthened analysis of the sublime in modernity, providing the basis for their own Kant was Edmund Burke, with his piece A philosophical investigation on the ideas of the sublime and the beautiful. The third criticism of Kant devoted a special moment to the analysis of the sublime, which had served as basis also for Schopenhauer, however, from her built his own aesthetic that would be of paramount importance Nieztsche for the young, mainly due to the consideration of music as sublime art. Nietzsche, then built his tragic wisdom, with based on the experience of the sublime tragedy.The question this paper wants to treat it exactly: It is possible think of a metaphysics of the sublime, based on Nietzsche?

Enthalpy of sublimation as measured using a silicon oscillator

Science.gov (United States)

Shakeel, Hamza; Pomeroy, J. M.

In this study, we report the enthalpy of sublimation of common gases (nitrogen, oxygen, argon, carbon dioxide, neon, krypton, xenon, and water vapor) using a large area silicon oscillator with a sub-ng (~0.027 ng/cm2) mass sensitivity. The double paddle oscillator design enables high frequency stability (17 ppb) at cryogenic temperatures and provides a consistent technique for enthalpy measurements. The enthalpies of sublimation are derived from the rate of mass loss during programmed thermal desorption and are detected as a change in the resonance frequency of the self-tracking oscillator. These measured enthalpy values show excellent agreement with the accepted literature values.

Vacuum system and cleaning techniques in the FTU machines

International Nuclear Information System (INIS)

Alessandrini, C.; Apicella, M.L.; Ferro, C.

1988-01-01

FTU (Frascati Tokamak Upgrade) is a high magnetic field (8T) tokamak under construction at the Frascati Energy Research Center (ENEA). Its vacuum systems has been already manifactured and is presently being assembled. It consist of an all metallic fully welded vessel, pumped by six turbomolecular pumps. The vacuum system has been dimensioned to allow a base pressure lower than 2.6 x 10 -6 Pa. The paper reports the design philosophy of the vacuum system. The results of the cleaning techniques performed on a 1:1 scale toroidal sector of FTU are also presented and discussed

Sublime Imperfections : Annotated Reading List

NARCIS (Netherlands)

Rutten, E.

2016-01-01

In this reading list, I share thoughts on scholars and journalists from which the Sublime Imperfections project takes its inspiration. The authors of the texts that I clustered ponder the nexus between the imperfect and the sublime, they rethink repair and breakdown, they critically interrogate and

2XIIB vacuum vessel: a unique design

International Nuclear Information System (INIS)

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

1975-01-01

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

"Rendezvous technique" for intraluminal vacuum therapy of anastomotic leakage of the jejunum.

Science.gov (United States)

Krajinovic, K; Reimer, S; Kudlich, T; Germer, C T; Wiegering, A

2016-12-01

Anastomotic leakage (AL) is one of the most common and serious complications following visceral surgery. In recent years, endoluminal vacuum therapy has dramatically changed therapeutic options for AL, but its use has been limited to areas easily accessible by endoscope. We describe the first use of endoluminal vacuum therapy in the small intestine employing a combined surgical and endoscopic "rendezvous technique" in which the surgeon assists the endoscopic placement of an endoluminal vacuum therapy sponge in the jejunum by means of a pullback string. This technique led to a completely closed AL after 27 days and 7 changes of the endosponge. The combined surgical and endoscopic rendezvous technique can be useful in cases of otherwise difficult endosponge placement.

Modelling Sublimation of Carbon Dioxide

Science.gov (United States)

Winkel, Brian

2012-01-01

In this article, the author reports results in their efforts to model sublimation of carbon dioxide and the associated kinetics order and parameter estimation issues in their model. They have offered the reader two sets of data and several approaches to determine the rate of sublimation of a piece of solid dry ice. They presented several models…

Practical sublimation source for large-scale chromium gettering in fusion devices

International Nuclear Information System (INIS)

Simpkins, J.E.; Emerson, L.C.; Mioduszewski, P.K.

1983-01-01

This paper describes the technique of chromium gettering with a large-scale sublimation source which resembles in its design the VARIAN Ti-Ball. It consists of a hollow chromium sphere with a diameter of approximately 3 cm and an incandescent filament for radiation heating from inside the ball. While the fabrication of the source is described in a companion paper, we discuss here the gettering technique. The experimental arrangement consists of an UHV system instrumented for total- and partial-pressure measurements, a film-thickness monitor, thermocouples, an optical pyrometer, and appropriate instrumentation to measure the heating power. The results show the temperature and corresponding sublimation rate of the Cr-Ball as function of input power. In addition, an example of the total pumping speed of a gettered surface is shown

O Sublime explicado às crianças

Directory of Open Access Journals (Sweden)

Virginia Figueiredo

2011-01-01

Full Text Available Como o próprio título indica, este ensaio pretende dialogar com a recepção do sublime kantiano pela filosofia francesa contemporânea, sobretudo com Jean-François Lyotard. Dessa forma, ao invés de ressaltar as consequências inevitável ou sistematicamente morais do sublime kantiano, como fez, de um modo geral, o comentário mais tradicional da filosofia crítica de Kant, este ensaio tenta interpretar o sublime como sendo essencialmente uma experiência da arte, seguindo assim de perto aquela tradição francesa. Mas, ao mesmo tempo, tomando alguma distância, este texto quer fazer uma objeção ao fundamento exclusivamente burkiano da concepção de sublime de Lyotard. Em suma, quero defender que é possível privilegiar o tempo (aspecto central do sublime de Edmund Burke, segundo Lyotard também na experiência do sublime kantiano.

Early counterpulse technique applied to vacuum interrupters

International Nuclear Information System (INIS)

Warren, R.W.

1979-11-01

Interruption of dc currents using counterpulse techniques is investigated with vacuum interrupters and a novel approach in which the counterpulse is applied before contact separation. Important increases have been achieved in this way in the maximum interruptible current as well as large reductions in contact erosion. The factors establishing these new limits are presented and ways are discussed to make further improvements

Sacred Space and Sublime Sacramental Piety

DEFF Research Database (Denmark)

Petersen, Nils Holger

2012-01-01

Analyses and Discussions of Mozart's Sacramental Litanies K. 125 and K. 243 in relation to the notions of the Sacred and the Sublime.......Analyses and Discussions of Mozart's Sacramental Litanies K. 125 and K. 243 in relation to the notions of the Sacred and the Sublime....

The vacuum interlock system for the CELSIUS ring

International Nuclear Information System (INIS)

Gajewski, K.

1990-01-01

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

Schopenhauer, Nietzsche, and the Aesthetically Sublime

Science.gov (United States)

Vandenabeele, Bart

2003-01-01

Much has been written on the relationship between Arthur Schopenhauer and Friedrich Nietzsche. Much remains to be said, however, concerning their respective theories of the sublime. In this article, the author first argues against the traditional, dialectical view of Schopenhauer's theory of the sublime that stresses the crucial role the sublime…

Early counterpulse technique applied to vacuum interrupters

International Nuclear Information System (INIS)

Warren, R.W.

1979-01-01

Interruption of dc currents using counterpulse techniques is investigated with vacuum interrupters and a novel approach in which the counterpulse is applied before contact separation. Important increases have been achieved in this way in the maximum interruptible current and large reductions in contact erosion. The factors establishing these new limits are presented and ways are discussed to make further improvements to the maximum interruptible current

Enhanced performance of CdS/CdTe thin-film devices through temperature profiling techniques applied to close-spaced sublimation deposition

Energy Technology Data Exchange (ETDEWEB)

Xiaonan Li; Sheldon, P.; Moutinho, H.; Matson, R. [National Renewable Energy Lab., Golden, CO (United States)

1996-05-01

The authors describe a methodology developed and applied to the close-spaced sublimation technique for thin-film CdTe deposition. The developed temperature profiles consisted of three discrete temperature segments, which the authors called the nucleation, plugging, and annealing temperatures. They have demonstrated that these temperature profiles can be used to grow large-grain material, plug pinholes, and improve CdS/CdTe photovoltaic device performance by about 15%. The improved material and device properties have been obtained while maintaining deposition temperatures compatible with commercially available substrates. This temperature profiling technique can be easily applied to a manufacturing environment by adjusting the temperature as a function of substrate position instead of time.

Sublimity and beauty: A view from nursing aesthetics.

Science.gov (United States)

Siles-González, José; Solano-Ruiz, Carmen

2016-03-01

Several authors have focused on the aesthetics of nursing care from diverse perspectives; however, there are few studies about the sublime and the beautiful in nursing. To identify beautiful and sublime moments in the context of the aesthetics of nursing care. A theoretical reflection has been contemplated about sublime and beautiful values in the context of the aesthetics of nursing care from the cultural history perspective. For that purpose, a revision of this issue has been completed. The terms 'beautiful' and 'sublime' have been analysed to identify the characteristics of both in the context of nursing care. We have followed all ethical requirements regarding the sources, conducting research and authorship. There is no conflict of interest in this paper. With aesthetic knowledge, the nurse expresses the artistic nature of nursing care by appreciating the act of caring for individuals. The sublime is a complex phenomenon, since apparently contrary feelings are interwoven. Nursing care is an art with an anthropological object-subject on which the 'artist' applies their prior knowledge and skills. Feelings and emotions that develop during the clinical nursing practice - especially at times sublime and beautiful, aesthetic - constitute experiences which are professionally significant. © The Author(s) 2015.

The enthalpy of sublimation of cubane

International Nuclear Information System (INIS)

Bashir-Hashemi, A.; Chickos, James S.; Hanshaw, William; Zhao Hui; Farivar, Behzad S.; Liebman, Joel F.

2004-01-01

The sublimation enthalpy of cubane, a key reference material for force field and quantum mechanical computations, was measured by combining the vaporization enthalpy at T = 298.15 K to the sum of the fusion enthalpy measured at T = 405 K and a solid-solid phase transition that occurs at T 394 K. The fusion and solid-solid phase transitions were measured previously. A sublimation enthalpy value of (55.2 ± 2.0) kJ mol -1 at T = 298.15 K was obtained. This value compares quite favorably the value obtained by comparing the sublimation enthalpy of similar substances as a function of their molar masses but is at odds with earlier measurements

The enthalpy of sublimation of cubane

Energy Technology Data Exchange (ETDEWEB)

Bashir-Hashemi, A.; Chickos, James S.; Hanshaw, William; Zhao Hui; Farivar, Behzad S.; Liebman, Joel F

2004-12-15

The sublimation enthalpy of cubane, a key reference material for force field and quantum mechanical computations, was measured by combining the vaporization enthalpy at T = 298.15 K to the sum of the fusion enthalpy measured at T = 405 K and a solid-solid phase transition that occurs at T 394 K. The fusion and solid-solid phase transitions were measured previously. A sublimation enthalpy value of (55.2 {+-} 2.0) kJ mol{sup -1} at T = 298.15 K was obtained. This value compares quite favorably the value obtained by comparing the sublimation enthalpy of similar substances as a function of their molar masses but is at odds with earlier measurements.

Obtention of thin depositions by the vacuum evaporation technique

International Nuclear Information System (INIS)

Gonzalez Mateu, D.; Labrada, A.; Voronin, A.

1991-01-01

The vacuum evaporating technique used to prepare thin depositions, and the technical characteristics of the constructed installation are described. 235 U y 238 U nuclear target for the fission researches were obtained. Aluminium and gold self-supporting foils were obtained too

O paradoxo sublime ou a alforria da arte

Directory of Open Access Journals (Sweden)

Virgínia Figueiredo

2015-01-01

Full Text Available Neste texto, pretendo analisar a tese principal do ensaio “A verdade sublime” de Philippe Lacoue-Labarthe, a qual poderia ser formulada do seguinte modo: a verdade sublime é o Ereignis, esse é o fundamento a partir do qual se desenvolveu uma dificílima operação que consistiu em modificar a tradição do sublime sempre apresentado negativamente naquilo que Lacoue-Labarthe chamou de "compreensão afirmativa do sublime ou da grande arte". O autor estabelece uma astuciosa aliança entre o que há de mais radical no pensamento de Heidegger e o sublime, tratado de maneira bastante polêmica, como a principal teoria da arte de Kant. Dessa articulação fundamental, pode-se concluir que ele não está apenas à procura de uma “Estética” (sequer de uma “Teoria da Arte” sublime, mas, em busca de algo que é muito mais ambicioso, a saber: de um pensamento do sublime. Portanto, na minha opinião, o ensaio lacouelabarthiano constitui, por um lado, uma referência indispensável não só a quem quer que pretenda estudar a tradição do sublime, mas, por outro, compreender o pensamento heideggeriano sobre a arte e sua tentativa de encontrar uma determinação mais essencial e, sobretudo, ousaria dizer, mais política da arte.

Alan Paton's Sublime: Race, Landscape and the Transcendence of ...

African Journals Online (AJOL)

This article develops a postcolonial reading of the sublime by suggesting that aesthetic theories of the sublime were, in their classical philosophical formulations by Edmund Burke and Immanuel Kant, founded on problematic assumptions of racial difference. In the colonial sphere, it is argued, the sublime could discursively ...

Kinetics of dihydro-dibenz[b,f]azepine derivatives sublimation

International Nuclear Information System (INIS)

Krongauz, V.V.; Ling, M.T.K.; Woo, L.; Purohit, U.

2007-01-01

Sublimation of dihydro-dibenz[b,f]azepine derivatives upon heating was studied and confirmed by thermogravimetry (TGA) and differential scanning calorimetry (DSC). DSC was used to analyze thermodynamics of melting. The kinetics of dihydro-dibenz[b,f]azepine derivatives sublimation were monitored by TGA as a function of temperature. Activation energies of sublimation were deduced and correlated with melting enthalpies and molecular structure. The results indicated that the sublimation was controlled by intermolecular forces in the crystalline lattice of dihydro-dibenz[b,f]azepine derivatives

Schopenhauer e os paradoxos do sublime

Directory of Open Access Journals (Sweden)

François Arnaud

2012-08-01

Full Text Available http://dx.doi.org/10.5007/1677-2954.2012v11nesp1p153 A principal distinção entre a concepção schopenhaueriana e kantiana do sublime reside, segundo este artigo, no fato que o observador, no último caso, deve ser submetido a um perigo apenas possível, enquanto no primeiro caso ele deve ser realmente amedrontado. O principal impulso do sentimento do sublime é de fato, em Schopenhauer, a intervenção da vontade, que deve ser portanto realmente ameaçada. Daí resultam alguns paradoxos e originalidades da teoria do sublime de Schopenhauer, principalmente de um ponto de vista ético, cujos vestígios eu tento seguir.

Sublimation From Snow in Northern Environments

Science.gov (United States)

Pomeroy, J. W.

2002-12-01

Sublimation from snow is an often neglected component of water and energy balances. Research under the Mackenzie GEWEX Study has attempted to understand the snow and atmospheric processes controlling sublimation and to estimate the magnitude of sublimation in high latitude catchments. Eddy correlation units were used to measure vertical water vapour fluxes from a high latitude boreal forest, snow-covered tundra and shrub-covered tundra in Wolf Creek Research Basin, near Whitehorse Yukon, Territory Canada. Over Jan-Apr. water vapour fluxes from the forest canopy amounted to 18.3 mm, a significant loss from winter snowfall of 54 mm. Most of this loss occurred when the canopy was snow-covered. The weight of snow measured on a suspended, weighed tree indicates that this flux is dominated by sublimation of intercepted snow. In the melt period (April), water vapour fluxes were uniformly small ranging from 0.21 mm/day on the tundra slope, 0.23 mm/day for the forest and 0.27 mm/day for the shrub-tundra. During the melt period the forest and shrub canopies was snow-free and roots were frozen, so the primary source of water vapour from all sites was the surface snow.

Modified sandwich vacuum pack technique for temporary closure of abdominal wounds: an African perspective.

Science.gov (United States)

van As, A B; Navsaria, P; Numanoglu, A; McCulloch, M

2007-01-01

South Africa has very high levels of accidental trauma as well as interpersonal violence. There are more admissions for trauma in South Africa than for any other disease; therefore it can be regarded as the Number 1 disease in the country. Complex abdominal injuries are common, requiring specific management techniques. The aim is to document our experience with the Modified Sandwich Vacuum Pack technique for temporary closure of abdominal wounds. After providing a short historical overview, we will demonstrate the technique which we carefully adapted over the last decade to the present Modified Sandwich Vacuum Pack technique. In the Last 5 years we utilized our Modified Sandwich Vacuum Pack technique 153 times in 69 patients. Five (5) patients were under the age of 12 years. In the patient group over 12 years the most common indication for using our technique were penetrating injuries (40), abdominal sepsis (28), visceral edema (10), abdominal compartment syndrome (9), abdominal packs (6),Abdominal wall defects (2). In the group under 12-years the 2 children had liver ruptures (posttraumatic) and 3 liver transplantations. The average cost for the materials used with our technique was ZAR 96. (10 Euro and 41 cents). In our experience the Modified Sandwich Vacuum Pack technique is an effective, cheap methodology to deal with open abdomens in the African setting.A drawback may be the technical expertise required, particular in centers dealing with low numbers of complex abdominal trauma.

Sublimation thermodynamics of four fluoroquinolone antimicrobial compounds

International Nuclear Information System (INIS)

Blokhina, Svetlana; Sharapova, Angelica; Ol’khovich, Marina; Perlovich, German

2017-01-01

Highlights: • The vapor pressures of ciprofloxacin, enrofloxacin, norfloxacin and levofloxacin were measured. • The values of enthalpies, entropies and Gibbs energies of sublimation were calculated at T = 298.15 K. • Thermophysical characteristics of the studied compounds were determined. • The influence hydrogen bonds in crystal lattices on the sublimation enthalpy was discussed. - Abstract: The transpiration method was used to measure the vapor pressures as a function of temperature of the following antimicrobial drugs: ciprofloxacin, enrofloxacin, norfloxacin and levofloxacin. Based on these results standard molar enthalpies, entropies and Gibbs energies of sublimation at T = 298.15 K were calculated and a correlation between the crystal lattice energy and the saturation vapor pressure in a number of fluoroquinolones was found. The thermophysical characteristics of the compounds studied were determined by DSC. The influence of different structural fragments of molecules substituents and the effects of hydrogen bonds in crystal lattices on the sublimation enthalpy was discussed.

Ultra high vacuum system for Isabelle full cell

International Nuclear Information System (INIS)

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

1979-01-01

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

High Vacuum Techniques for Anionic Polymerization

KAUST Repository

Ratkanthwar, Kedar

2015-09-01

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

Application of ion beam analysis to the selective sublimation processing of thin films for gas sensing

International Nuclear Information System (INIS)

Vomiero, A.; Scian, C.; Della Mea, G.; Guidi, V.; Martinelli, G.; Schiffrer, G.; Comini, E.; Ferroni, M.; Sberveglieri, G.

2006-01-01

Ion beam analysis was successfully applied to a novel technique, named selective sublimation process (SSP), for deposition of nanostructured gas-sensing films through reactive sputtering. The method consists of the co-deposition of a mixed oxide, one of which has a relatively low sublimation temperature. Annealing at suitable temperature causes the sublimation of the most volatile compound, leaving a layer with adjustable composition. The appropriate choice of thermal treatments and the consequent tailoring of the composition play a crucial role in the determination of the microstructural properties. We developed a model based on diffusion equations that provides a useful guide to control the deposition and processing parameters and we applied the model on the systems TiO 2 -WO 3 and TiO 2 -MoO 3 . Rutherford backscattering (RBS) was demonstrated to be effective for the characterization of the diffusion and sublimation processes during SSP. Experimental results fully agree with theoretical prediction, and allowed the calculation of all the parameters involved in SSP

The Sublime, Ugliness and Contemporary Art: A Kantian Perspective

Directory of Open Access Journals (Sweden)

Mojca Kuplen

2015-06-01

Full Text Available The aim of this paper is twofold. First, to explain the distinction between Kant’s notions of the sublime and ugliness, and to answer an important question that has been left unnoticed in contemporary studies, namely why it is the case that even though both sublime and ugliness are contrapurposive for the power of judgment, occasioning the feeling of displeasure, yet that after all we should feel pleasure in the former, while not in the latter. Second, to apply my interpretation of the sublime and ugliness to contemporary art, and to resolve certain issues that have been raised in accounting for the possibility of artistic sublimity. I argue that an experience of a genuine artistic sublimity is an uncommon occurrence. I propose that the value of contemporary art can be best explained by referring to Kant’s notion of ugliness and his theory of aesthetic ideas.

UHV testing of upgraded vacuum chambers for Indus-1

International Nuclear Information System (INIS)

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

2013-01-01

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

Snow sublimation in mountain environments and its sensitivity to forest disturbance and climate warming

Science.gov (United States)

Sexstone, Graham A.; Clow, David W.; Fassnacht, Steven R.; Liston, Glen E.; Hiemstra, Christopher A.; Knowles, John F.; Penn, Colin A.

2018-01-01

Snow sublimation is an important component of the snow mass balance, but the spatial and temporal variability of this process is not well understood in mountain environments. This study combines a process‐based snow model (SnowModel) with eddy covariance (EC) measurements to investigate (1) the spatio‐temporal variability of simulated snow sublimation with respect to station observations, (2) the contribution of snow sublimation to the ablation of the snowpack, and (3) the sensitivity and response of snow sublimation to bark beetle‐induced forest mortality and climate warming across the north‐central Colorado Rocky Mountains. EC‐based observations of snow sublimation compared well with simulated snow sublimation at stations dominated by surface and canopy sublimation, but blowing snow sublimation in alpine areas was not well captured by the EC instrumentation. Water balance calculations provided an important validation of simulated sublimation at the watershed scale. Simulated snow sublimation across the study area was equivalent to 28% of winter precipitation on average, and the highest relative snow sublimation fluxes occurred during the lowest snow years. Snow sublimation from forested areas accounted for the majority of sublimation fluxes, highlighting the importance of canopy and sub‐canopy surface sublimation in this region. Simulations incorporating the effects of tree mortality due to bark‐beetle disturbance resulted in a 4% reduction in snow sublimation from forested areas. Snow sublimation rates corresponding to climate warming simulations remained unchanged or slightly increased, but total sublimation losses decreased by up to 6% because of a reduction in snow covered area and duration.

Feasibilty study of renewable energy powered seawater desalination technology using natural vacuum technique

Energy Technology Data Exchange (ETDEWEB)

Ayhan, Teoman; Al Madani, Hussain [Mechanical Engineering Department, College of Engineering, University of Bahrain, P.O. box 32038, Isatown 32036 (Bahrain)

2010-02-15

With an ever-increasing population and rapid growth of industrialization, there is great demand for fresh water. Desalination has been a key proponent to meet the future challenges due to decreasing availability of fresh water. However, desalination uses significant amount of energy, today mostly from fossil fuels. It is, therefore, reasonable to rely on renewable energy sources such as solar energy, wind energy, ocean thermal energy, waste heat from the industry and other renewable sources. The present study deals with the energy-efficient seawater desalination system utilizing renewable energy sources and natural vacuum technique. A new desalination technology named Natural Vacuum Desalination is proposed. The novel desalination technique achieve remarkable energy efficiency through the evaporation of seawater under vacuum and will be described in sufficient detail to demonstrate that it requires much less electric energy compared to any conventional desalination plant of fresh water production of similar capacity. The discussion will highlight the main operative and maintenance features of the proposed natural vacuum seawater desalination technology which seems to have promising techno-economic potential providing also advantageous coupling with renewable energy sources. (author)

The Religious-Sublime in Music, Literature and Architecture

DEFF Research Database (Denmark)

Cifuentes-Aldunate, Claudio

2018-01-01

The present article is an attempt to propose the semiotic aspect that produces the ”religious- sublime”. Most of the semiotic characteristics that we use to represent (and produce) the signifiers of the religious-sublime, nevertheless, share their mechanisms with other modalities of ”sublimeness......”. The sublime will be regarded as the representation (in the sense of staging) of a perception. I will propose how the subjective perception – in this case of the divinity - is (re)constructed by the subject in a piece of Spanish Gothic literature, in sacred music and in architecture – the room which houses...

New Perspectives on Blowing Snow Transport, Sublimation, and Layer Thermodynamic Structure over Antarctica

Science.gov (United States)

Palm, Steve; Kayetha, Vinay; Yang, Yuekui; Pauly, Rebecca M.

2017-01-01

Blowing snow over Antarctica is a widespread and frequent event. Satellite remote sensing using lidar has shown that blowing snow occurs over 70% of the time over large areas of Antarctica in winter. The transport and sublimation of blowing snow are important terms in the ice sheet mass balance equation and the latter is also an important part of the hydrological cycle. Until now the only way to estimate the magnitude of these processes was through model parameterization. We present a technique that uses direct satellite observations of blowing snow and model (MERRA-2) temperature and humidity fields to compute both transport and sublimation of blowing snow over Antarctica for the period 2006 to 2016. The results show a larger annual continent-wide integrated sublimation than current published estimates and a significant transport of snow from continent to ocean. The talk will also include the lidar backscatter structure of blowing snow layers that often reach heights of 200 to 300 m as well as the first dropsonde measurements of temperature, moisture and wind through blowing snow layers.

R&D ERL: Vacuum

Energy Technology Data Exchange (ETDEWEB)

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

2010-01-01

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

Spectroscopy of lithium atoms sublimated from isolation matrix of solid Ne.

Science.gov (United States)

Sacramento, R L; Scudeller, L A; Lambo, R; Crivelli, P; Cesar, C L

2011-10-07

We have studied, via laser absorption spectroscopy, the velocity distribution of (7)Li atoms released from a solid neon matrix at cryogenic temperatures. The Li atoms are implanted into the Ne matrix by laser ablation of a solid Li precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms at around 12 K. We find interesting differences in the velocity distribution of the released Li atoms from the model developed for our previous experiment with Cr [R. Lambo, C. C. Rodegheri, D. M. Silveira, and C. L. Cesar, Phys. Rev. A 76, 061401(R) (2007)]. This may be due to the sublimation regime, which is at much lower flux for the Li experiment than for the Cr experiment, as well as to the different collisional cross sections between those species to the Ne gas. We find a drift velocity compatible with Li being thermally sublimated at 11-13 K, while the velocity dispersion around this drift velocity is low, around 5-7 K. With a slow sublimation of the matrix we can determine the penetration depth of the laser ablated Li atoms into the Ne matrix, an important information that is not usually available in most matrix isolation spectroscopy setups. The present results with Li, together with the previous results with Cr suggest this to be a general technique for obtaining cryogenic atoms, for spectroscopic studies, as well as for trap loading. The release of the isolated atoms is also a useful tool to study and confirm details of the matrix isolated atoms which are masked or poorly understood in the solid. © 2011 American Institute of Physics

Sublime frequencies:  The construction of sublime listening experiences in the sonification of scientific data.

Science.gov (United States)

Supper, Alexandra

2014-02-01

In the past two decades, the sonification of scientific data - an auditory equivalent of data visualization in which data are turned into sounds - has become increasingly widespread, particularly as an artistic practice and as a means of popularizing science. Sonification is thus part of the recent trend, discussed in public understanding of science literature, towards increased emphasis on 'interactivity' and 'crossovers' between science and art as a response to the perceived crisis in the relationship between the sciences and their publics. However, sonification can also be understood as the latest iteration in a long tradition of theorizing the relations between nature, science and human experience. This article analyses the recent public fascination with sonification and argues that sonification grips public imaginations through the promise of sublime experiences. I show how the 'auditory sublime' is constructed through varying combinations of technological, musical and rhetorical strategies. Rather than maintain a singular conception of the auditory sublime, practitioners draw on many scientific and artistic repertoires. However, sound is often situated as an immersive and emotional medium in contrast to the supposedly more detached sense of vision. The public sonification discourse leaves intact this dichotomy, reinforcing the idea that sound has no place in specialist science.

Vacuum system for the LBL Advanced Light Source (ALS)

International Nuclear Information System (INIS)

Kennedy, K.; Henderson, T.; Meneghetti, J.

1989-03-01

A 1.5 to 1.9 GeV synchrotron light source is being built at LBL. The vacuum system is designed to permit most synchrotron photons to escape the electron channel and be absorbed in an antechamber. The gas generated by the photons hitting the absorbers in the antechambers will be pumped by titanium sublimation pumps located directly under the absorbers. The electron channel and the antechamber are connected by a 10-mm-high slot that offers good electrodynamic isolation of the two chambers of frequencies affecting the store electron orbit. Twelve 10-meter-long vessels constitute the vacuum chambers for all the lattice magnets. Each chamber will be machined from two thick plates of 5083-H321 aluminum and welded at the perimeter. Machining both the inside and outside of the vacuum chamber permits the use of complex and accurate surfaces. The use of thick plates allows flanges to be machined directly into the wall of each chamber, thus avoiding much welding. 1 ref., 3 figs

Relationships between fusion, solution, vaporization and sublimation enthalpies of substituted phenols

International Nuclear Information System (INIS)

Yagofarov, Mikhail I.; Nagrimanov, Ruslan N.; Solomonov, Boris N.

2017-01-01

Highlights: • Method for determination of sublimation and vaporization enthalpies of phenols was developed. • Vaporization enthalpies of 28 phenols at 298 K were calculated. • Sublimation enthalpies of 26 phenols at 298 K were calculated using fusion enthalpies at melting temperatures. • Obtained values are in good agreement with the results of conventional methods. - Abstract: In this work a method for determination of sublimation and vaporization enthalpies of substituted phenols was developed. This method is a modification of solution calorimetry approach. Modification is based on the novel relations, which bind solution, vaporization and sublimation enthalpies at 298.15 K and fusion enthalpy at the melting temperature. According to novel relations the equations for calculating sublimation and vaporization enthalpies at 298.15 K were offered. Calculated values of sublimation and vaporization enthalpies of phenol derivatives containing alkyls, halogens, –OCH 3 , –NO 2 , –COCH 3 , –COOCH 3 groups, and dihydroxybenzenes were compared with literature data (298.15 K) obtained by conventional methods. In most of the cases divergence does not exceed 2–3%.

Investigation of the process of vacuum freeze drying of bacterial concentrates for the meat industry with cryogenic freezing

Directory of Open Access Journals (Sweden)

V. V. Poymanov

2016-01-01

Full Text Available The research results of the nutritional value of the products manufactured are presented in the article. The main directions of bacterial concentrates application in the meat industry were determined. The analysis of starter cultures was given. The range of products manu-factured with bacterial concentrates was analyzed. It was shown that the introduction of innovative technologies will enable dynamic development of both large and small enterprises, which will create prerequisites for the growth of the Russian market of meat products. Economic efficiency of the studied substances treatment methods was proved. The relevance of the development of technology of pro-duction of dry bacterial concentrates with cryogenic freezing was proved. An integrated approach to the development of competitive domestic technologies and equipment for cryofreezing and sublimation dehydration by the use of granulation for the intensification of the internal heat and mass transfer, reducing specific energy consumption through the use of a combined cold supply system was pro-posed. Results of the study of the kinetics of the freezing process with the traditional method and cryofreezing are given in the paper. Rational parameters of the cryofreezing process were proposed. The optimum composition of cryoprotective medium was recommended. The research of the process of bacterial concentrate vacuum sublimation dehydration in the layer and granular form were conducted. The research confirmed that the use of the cryofreezing and granulation can increase the number of viable microorganisms in the bacterial concentrate and reduce the drying time. Rational vacuum sublimation dehydration modes were proposed. Methods of reduc-ing the defects of the processed products and improvement of the efficiency of production facilities were specified. Quality indicators of dried bacterial concentrates were given. The results obtained allow to carry out engineering calculations

Sublimation, culture, and creativity.

Science.gov (United States)

Kim, Emily; Zeppenfeld, Veronika; Cohen, Dov

2013-10-01

Combining insights from Freud and Weber, this article explores whether Protestants (vs. Catholics and Jews) are more likely to sublimate their taboo feelings and desires toward productive ends. In the Terman sample (Study 1), Protestant men and women who had sexual problems related to anxieties about taboos and depravity had greater creative accomplishments, as compared to those with sexual problems unrelated to such concerns and to those reporting no sexual problems. Two laboratory experiments (Studies 2 and 3) found that Protestants produced more creative artwork (sculptures, poems, collages, cartoon captions) when they were (a) primed with damnation-related words, (b) induced to feel unacceptable sexual desires, or (c) forced to suppress their anger. Activating anger or sexual attraction was not enough; it was the forbidden or suppressed nature of the emotion that gave the emotion its creative power. The studies provide possibly the first experimental evidence for sublimation and suggest a cultural psychological approach to defense mechanisms.

Comparative study of CdTe sources used for deposition of CdTe thin films by close spaced sublimation technique

Directory of Open Access Journals (Sweden)

Wagner Anacleto Pinheiro

2006-03-01

Full Text Available Unlike other thin film deposition techniques, close spaced sublimation (CSS requires a short source-substrate distance. The kind of source used in this technique strongly affects the control of the deposition parameters, especially the deposition rate. When depositing CdTe thin films by CSS, the most common CdTe sources are: single-crystal or polycrystalline wafers, powders, pellets or pieces, a thick CdTe film deposited onto glass or molybdenum substrate (CdTe source-plate and a sintered CdTe powder. In this work, CdTe thin films were deposited by CSS technique from different CdTe sources: particles, powder, compact powder, a paste made of CdTe and propylene glycol and source-plates (CdTe/Mo and CdTe/glass. The largest deposition rate was achieved when a paste made of CdTe and propylene glycol was used as the source. CdTe source-plates led to lower rates, probably due to the poor heat transmission, caused by the introduction of the plate substrate. The results also showed that compacting the powder the deposition rate increases due to the better thermal contact between powder particles.

The sublime and the grotesque: obscenity in Hilda Hilst

Directory of Open Access Journals (Sweden)

Jo A-mi

2016-08-01

Full Text Available The present work aims to discuss the dialogical relationship between sublime and grotesque in the work A obscena Senhora D by Hilda Hilst, based on its status of contemporary fiction permeated by reconditioning of the language in its performance in the non-linear time. In this sense, it was used studies of the sublime, as a historical and philosophical and literary concept in the works of Longinus, Edmund Burke, Immanuel Kant, Victor Hugo and François Lyotard; issues relating to discussions on the grotesque and its dialogue with the sublime ways, the works of Mikhail Bakhtin and Michel Maffesoli had great importance - the poetic and obscene relationship of the work discussed in convergent concepts such as obscenity, eroticism, sacred and profane. From these analyzes, it was concluded that in A obscena senhora D the sublime and the grotesque show in a multifaceted character, contradictory, interlocutory, and therefore not exclusionary: solidifying the hybrid linguistic-imagistic flow of the hilstiana literature.

Sublimation as a landform-shaping process on Pluto

Science.gov (United States)

Moore, Jeffrey M.; Howard, Alan D.; Umurhan, Orkan M.; White, Oliver L.; Schenk, Paul M.; Beyer, Ross A.; McKinnon, William B.; Spencer, John R.; Grundy, Will M.; Lauer, Tod R.; Nimmo, Francis; Young, Leslie A.; Stern, S. Alan; Weaver, Harold A.; Olkin, Cathy B.; Ennico, Kimberly; New Horizons Science Team

2017-05-01

Fields of pits, both large and small, in Tombaugh Regio (Sputnik Planitia, and the Pitted Uplands to the east), and along the scarp of Piri Rupes, are examples of landscapes on Pluto where we conclude that sublimation drives their formation and evolution. Our heuristic modeling closely mimics the form, spacing, and arrangement of a variety of Tombaugh Regio's pits. Pluto's sublimation modified landforms appear to require a significant role for (diffusive) mass wasting as suggested by our modeling. In our models, the temporal evolution of pitted surfaces is such that initially lots of time passes with little happening, then eventually, very rapid development of relief and rapid sublimation. Small pits on Sputnik Planitia are consistent with their formation in N2-dominated materials. As N2-ice readily flows, some other ``stiffer'' volatile ice may play a role in supporting the relief of sublimation degraded landforms that exhibit several hundred meters of relief. A strong candidate is CH4, which is spectroscopically observed to be associated with these features, but the current state of rheological knowledge for CH4 ice at Pluto conditions is insufficient for a firm assessment.

Measured and modelled sublimation on the tropical Glaciar Artesonraju, Perú

Science.gov (United States)

Winkler, M.; Juen, I.; Mölg, T.; Wagnon, P.; Gómez, J.; Kaser, G.

2009-02-01

Sublimation plays a decisive role in the surface energy and mass balance of tropical glaciers. During the dry season (May-September) low specific humidity and high surface roughness favour the direct transition from ice to vapour and drastically reduce the energy available for melting. However, field measurements are scarce and little is known about the performance of sublimation parameterisations in glacier mass balance and runoff models. During 15 days in August 2005 sublimation was measured on the tongue of Glaciar Artesonraju (8°58' S, 77°38' W) in the Cordillera Blanca, Perú, using simple lysimeters. Indicating a strong dependence on surface roughness, daily totals of sublimation range from 1-3 kg m-2 for smooth to 2-5 kg m-2 for rough conditions. (The 15-day means at that time of wind speed and specific humidity were 4.3 m s-1 and 3.8 g kg-1, respectively.) Measured sublimation was related to characteristic surface roughness lengths for momentum (zm) and for the scalar quantities of temperature and water vapour (zs), using a process-based mass balance model. Input data were provided by automatic weather stations, situated on the glacier tongue at 4750 m a.s.l. and 4810 m a.s.l., respectively. Under smooth conditions the combination zm=2.0 mm and zs=1.0 mm appeared to be most appropriate, for rough conditions zm=20.0 mm and zs=10.0 mm fitted best. Extending the sublimation record from April 2004 to December 2005 with the process-based model confirms, that sublimation shows a clear seasonality. 60-90% of the energy available for ablation is consumed by sublimation in the dry season, but only 10-15% in the wet season (October-April). The findings are finally used to evaluate the parameterisation of sublimation in the lower-complexity mass balance model ITGG, which has the advantage of requiring precipitation and air temperature as only input data. It turns out that the implementation of mean wind speed is a possible improvement for the representation of

Freezer-sublimer for gaseous diffusion plant

International Nuclear Information System (INIS)

Reti, G.R.

1978-01-01

A method and apparatus is disclosed for freezing and subliming uranium hexafluoride (UF 6 ) as part of a gaseous diffusion plant from which a quantity of the UF 6 inventory is intermittently withdrawn and frozen to solidify it. A plurality of upright heat pipes holds a coolant and is arranged in a two compartment vessel, the lower compartment is exposed to UF 6 , the higher one serves for condensing the evaporated coolant by means of cooling water. In one embodiment, each pipe has a quantity of coolant such as freon, hermetically sealded therein. In the other embodiment, each pipe is sealed only at the lower end while the upper end communicates with a common vapor or cooling chamber which contains a water cooled condenser. The cooling water has a sufficiently low temperature to condense the evaporated coolant. The liquid coolant flows gravitationally downward to the lower end portion of the pipe. UF 6 gas is flowed into the tank where it contacts the finned outside surface of the heat pipes. Heat from the gas evaporates the coolant and the gas in turn is solidified on the exterior of the heat pipe sections in the tank. To recover UF 6 gas from the tank, the solidified UF 6 is sublimed by passing compressed UF 6 gas over the frozen UF 6 gas on the pipes or by externally heating the lower ends of the pipes sufficiently to evaporate the coolant therein above the subliming temperature of the UF 6 . The subliming UF 6 gas then condenses the coolant in the vertical heat pipes, so that it can gravitationally flow back to the lower end portions

Standard molar enthalpies of formation and of sublimation of the terphenyl isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.; Lima, Luis M. Spencer S.

2008-01-01

The standard (p 0 = 0.1 MPa) molar enthalpies of formation in the crystalline phases of ortho, meta and para-terphenyl isomers, at T = 298.15 K, were derived from the standard molar energies of combustion, measured by mini-bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the dependence of the vapour pressure of the crystals with the temperature, thus deriving their standard molar enthalpies of sublimation by means of the Clausius-Clapeyron equation. Combining the standard molar enthalpies of formation and sublimation of the crystalline terphenyls, the standard molar enthalpies of formation in the gaseous state, at T = 298.15 K, were derived for the three isomers. Results are provided in a table. The results show small but detectable isomerization enthalpies between the terphenyls, indicating the following relative enthalpic stabilities: m- > p- ∼ o-terphenyl

Implementation of complex nanosystems using a versatile ultrahigh vacuum nonlithographic technique

International Nuclear Information System (INIS)

Das, Biswajit; Banerjee, Arghya

2007-01-01

We have developed an ultrahigh vacuum technique for the implementation of complex nanosystems incorporating nonlithographic nanoparticles, ohmic contact metals and isolation dielectrics. The technique is compatible with the silicon integrated circuit manufacturing process and is versatile, allowing the deposition of nanoparticles of any metal, semiconductor or insulator with diameters as small as 2 nm with less than 5% size variation. In addition, the technique allows the creation of multi-layered structures of nanoparticles of different dimensions. The flexibility and the versatility of the technique have been demonstrated by depositing nanoparticles of various materials as well as fabricating multi-layered structures incorporating nanoparticles

R and D ERL: Vacuum

International Nuclear Information System (INIS)

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

2010-01-01

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

The enthalpy of sublimation and thermodynamic functions of fermium

International Nuclear Information System (INIS)

Haire, R.G.; Gibson, J.K.

1989-01-01

The enthalpy of sublimation of fermium (Fm), element 100, has now been determined directly by measuring the partial pressure of Fm over alloys, for the temperature range of 642 to 905 K. The partial pressures were determined using Knudsen effusion and target collection techniques. Dilute (10 -5 --10 -7 atom %) solid alloys of Fm and mixtures of Fm and Es in both Sm and Yb solvents were studied. The presence of Es in two of the alloys allowed a direct comparison of the behavior of Fm and Es, where the latter could be used as a reference. It was possible to calculate enthalpies of sublimation and a hypothetical vapor pressure/temperature relationship for pure Fm metal by selecting Yb as the solvent most likely to form a nearly ideal alloy with Fm. From the experimental vapor pressure data, we derived average Second Law values of 33.8±3 kcal/mol and 23.5±3 cal/mol deg for the enthalpy and entropy of sublimation of Fm at 298 K. Third Law enthalpy values were also calculated using the experimental partial pressure data and entropies estimated from derived free energy functions and heat capacities for the solid and gaseous forms of Fm. The average Third Law values (34.8 kcal/mol and 25.1 cal/mol deg, respectively, at 298 K) are in agreement with those obtained via the Second Law. These results establish that Fm, like Es (element 99), is a divalent metal. The finding that Fm metal is the second divalent actinide element experimentally establishes the trend towards metallic divalency expected in the second half of the actinide series

Reassessing Aesthetic Appreciation of Nature in the Kantian Sublime

Science.gov (United States)

Brady, Emily

2012-01-01

The sublime has been a relatively neglected topic in recent work in philosophical aesthetics, with existing discussions confined mainly to problems in Kant's theory. Given the revival of interest in his aesthetic theory and the influence of the Kantian sublime compared to other eighteenth-century accounts, this focus is not surprising. Kant's…

Scanning electron microscope observations of sublimates from Merapi Volcano, Indonesia

Science.gov (United States)

Symonds, R.

1993-01-01

Sublimates were sampled from high-temperature (up to 800??C) fumaroles at Merapi volcano in January 1984. Sampling is accomplished by inserting silica tubes into high-temperature vents. Volcanic glass flows through the tubes and sublimates precipitate on the inner walls in response to the temperature gradient. With decreasing temperature (800-500??C) in the tubes, there are five sublimate zones. Texturally, the sublimate phases grade from large, well-formed crystals at their highest-temperature occurrence to more numerous, smaller crystals that are less perfect at lower temperatures. These changes imply that the crystal nucleation and growth rates increase and decrease, respectively, as temperature decreases. Overall, the textural data suggest that the gas is saturated or slightly super-saturated with the phases at their hottest occurrence, but that the gas becomes increasingly super-saturated with the phases at lower temperatures. -from Author

Measured and modelled sublimation on the tropical Glaciar Artesonraju, Perú

Directory of Open Access Journals (Sweden)

M. Winkler

2009-02-01

Full Text Available Sublimation plays a decisive role in the surface energy and mass balance of tropical glaciers. During the dry season (May–September low specific humidity and high surface roughness favour the direct transition from ice to vapour and drastically reduce the energy available for melting. However, field measurements are scarce and little is known about the performance of sublimation parameterisations in glacier mass balance and runoff models.

During 15 days in August 2005 sublimation was measured on the tongue of Glaciar Artesonraju (8°58' S, 77°38' W in the Cordillera Blanca, Perú, using simple lysimeters. Indicating a strong dependence on surface roughness, daily totals of sublimation range from 1–3 kg m⁻² for smooth to 2–5 kg m⁻² for rough conditions. (The 15-day means at that time of wind speed and specific humidity were 4.3 m s⁻¹ and 3.8 g kg⁻¹, respectively.

Measured sublimation was related to characteristic surface roughness lengths for momentum (z_m and for the scalar quantities of temperature and water vapour (z_s, using a process-based mass balance model. Input data were provided by automatic weather stations, situated on the glacier tongue at 4750 m a.s.l. and 4810 m a.s.l., respectively. Under smooth conditions the combination z_m=2.0 mm and z_s=1.0 mm appeared to be most appropriate, for rough conditions z_m=20.0 mm and z_s=10.0 mm fitted best.

Extending the sublimation record from April 2004 to December 2005 with the process-based model confirms, that sublimation shows a clear seasonality. 60–90% of the energy available for ablation is consumed by sublimation in the dry season, but only 10–15% in the wet season (October–April. The findings are finally used to evaluate the parameterisation of sublimation in the lower-complexity mass

Measured and modelled sublimation on the tropical Glaciar Artesonraju, Perú

OpenAIRE

M. Winkler; I. Juen; T. Mölg; G. Kaser

2008-01-01

Sublimation plays a decisive role in the surface energy balance of tropical glaciers. During the dry season low specific humidity and high surface roughness favour the direct transition from ice to vapour and drastically reduce the energy available for melting. However, field measurements are scarce and little is known about the performance of sublimation parametrisations in glacier mass balance and runoff models.

During 15 days in August 2005 sublimation was measured on ...

Peculiarities of fullerenes condensation from molecular beam in vacuum

Directory of Open Access Journals (Sweden)

Neluba P. L.

2011-12-01

Full Text Available There was investigated С60 fullerenes condensation in vacuum on unheated Si, GaAs, isinglass stone substrates. There were used atomic-force microscopy, Raman scattering and measurement of mechanical stresses in films. It is established that the С60 molecule can decay on the substrates with the formation of other carbon structures in the condensate without supplementary physical effects on the sublimated beam in «evaporator — substrate» space. The possibility was found to increase the grain size and reduce the mechanical stresses in the condensate.

Effect of Dipping and Vacuum Impregnation Coating Techniques with Alginate Based Coating on Physical Quality Parameters of Cantaloupe Melon.

Science.gov (United States)

Senturk Parreidt, Tugce; Schmid, Markus; Müller, Kajetan

2018-04-01

Edible coating based on sodium alginate solution was applied to fresh-cut cantaloupe melon by dipping and vacuum impregnation coating methods. One aim of this work is to produce more technical information concerning these conventional and novel coating processes. For this purpose, the effect of various coating parameters (dipping time, draining time, time length of the vacuum period, vacuum pressure, atmospheric restoration time) with several levels on physical quality parameters (percentage of weight gain, color, and texture) of noncoated and coated samples were determined in order to define adequate coating process parameters to achieve a successful coating application. Additionally, the effects of dipping and vacuum impregnation processes were compared. Both processes improved the firmness of the melon pieces. However, vacuum impregnation application had higher firmness and weight gain results, and had significant effect (P coating technique and the parameters used significantly affect the physical quality characteristics of coated food products. The work presented produced more technical information concerning dipping and vacuum impregnation coating techniques, along with evaluating the effects of various coating parameters with several levels. The results revealed that vacuum impregnation technique is a successful coating method; however the effects should be carefully assessed for each product. © 2018 Institute of Food Technologists®.

Sublime Views and Beautiful Explanations

DEFF Research Database (Denmark)

Barry, Daved; Meisiek, Stefan; Hatch, Mary Jo

To create a generative theory that provides beautiful explanations and sublime views requires both a crafts and an art approach to scientific theorizing. The search for generativity leads scholars to perform various theorizing moves between the confines of simple, yet eloquent beauty...

A Low Cost Inflatable CubeSat Drag Brake Utilizing Sublimation

Science.gov (United States)

Horn, Adam Charles

The United Nations Inter-Agency Debris Coordination Committee has adopted a 25-year post-mission lifetime requirement for any satellite orbiting below 2000 km in order to mitigate the growing orbital debris threat. Low-cost CubeSats have become important satellite platforms with startling capabilities, but this guideline restricts them to altitudes below 600 km because they remain in orbit too long. In order to enable CubeSat deployments at higher release altitudes, a low-cost, ultra-reliable deorbit device is needed. This thesis reports on efforts to develop a deployable and passively inflatable drag brake that can deorbit from higher orbital altitudes, thereby complying with the 25-year orbital lifetime guideline. On the basis of concepts first implemented during the NASA Echo Satellite Project, this study investigated the design of an inflatable CubeSat drag device that utilizes sublimating benzoic acid powder as the inflation propellant. Testing has focused on demonstrating the functionality of charging a Mylar drag brake bladder with appropriate quantities of benzoic acid powder, and the exposure to a controlled-temperature vacuum chamber causing the bladder to inflate. Although results show a measureable increase in internal pressure when introduced to anticipated orbital temperatures, a significant air-derived expansion prior to sublimation was encountered due to the undetectable volume of ambient residual air in the fabricated membrane bladders. These tests have demonstrated the feasibility of this approach, thereby demonstrating that this concept can create a potentially smaller and less expensive drag device, eliminating inflation gas tanks and valves. In that way, this system can provide a low-cost, miniaturized system that reduces a CubeSat's orbital lifetime to less than 25 years, when placed at higher orbital altitude.

Modular Porous Plate Sublimator /MPPS/ requires only water supply for coolant

Science.gov (United States)

Rathbun, R. J.

1966-01-01

Modular porous plate sublimators, provided for each location where heat must be dissipated, conserve the battery power of a space vehicle by eliminating the coolant pump. The sublimator requires only a water supply for coolant.

Contributions to the analytical control of polyphenolic mixture

Energy Technology Data Exchange (ETDEWEB)

Barrera Pinero, R

1961-07-01

Separation and identification experiences of polyphenylic mixtures are described. the following technique are used: vacuum fractional distillation, vacuum sublimation and chromatography on acetylated paper. Also new coloured reactions of polyphenyls with aldehyde chlorides and their spectrophotometric application are studied. (Author) 17 refs.

Contributions to the analytical control of polyphenylic mixture

International Nuclear Information System (INIS)

Barrera Pinero, R.

1961-01-01

Separation and identification experiences of polyphenylic mixtures are described. the following technique are used: vacuum fractional distillation, vacuum sublimation and chromatography on acetylated paper. Also new coloured reactions of polyphenyls with aldehyde chlorides and their spectrophotometric application are studied. (Author) 17 refs

Formulation and evaluation of fast dissolving tablets of cinnarizine using superdisintegrant blends and subliming material

Directory of Open Access Journals (Sweden)

Biswajit Basu

2011-01-01

Full Text Available The aim of this investigation was to develop fast dissolving tablet of cinnarizine. A combination of super disintegrants, i.e., sodium starch glycolate (SSG and crosscarmellose sodium (CCS were used along with camphor as a subliming material. An optimized concentration of camphor was added to aid the porosity of the tablet. A 3 2 full factorial design was applied to investigate the combined effect of two formulation variables: Amount of SSG and CCS. Infrared (IR spectroscopy was performed to identify the physicochemical interaction between drug and polymer. IR spectroscopy showed that there is no interaction of drug with polymer. In the present study, direct compression was used to prepare the tablets. The powder mixtures were compressed into tablet using flat face multi punch tablet machine. Camphor was sublimed from the tablet by exposing the tablet to vacuum drier at 60°C for 12 hours. All the formulations were evaluated for their characteristics such as average weight, hardness, wetting time, friability, content uniformity, dispersion time (DT, and dissolution rate. An optimized tablet formulation (F 9 was found to have good hardness of 3.30 ± 0.10 kg/cm 2 , wetting time of 42.33 ± 4.04 seconds, DT of 34.67 ± 1.53 seconds, and cumulative drug release of not less than 99% in 16 minutes.

Operating status of TARN vacuum system and future tasks

International Nuclear Information System (INIS)

Chida, Katsuhisa; Tsujikawa, Hiroshi; Mizobuchi, Akira

1981-01-01

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

Thermodynamics of sublimation and solvation for bicyclo-derivatives of 1,3-thiazine

International Nuclear Information System (INIS)

Ol’khovich, Marina V.; Blokhina, Svetlana V.; Sharapova, Angelica V.; Perlovich, German L.; Proshin, Alexey N.

2013-01-01

Highlights: • Temperature dependencies of saturated vapor pressure of new bicyclo-derivatives were obtained. • Thermodynamic functions of sublimation and solvation were calculated. • The correlations between thermodynamic functions and molecular descriptors are discussed. - Abstract: Temperature dependencies of saturated vapor pressure of novel bicyclo-derivatives of 1,3-thiazine with methoxy- and carbonyl-substituents have been obtained by method of transference by means of an inert gas carrier. Thermodynamic functions of sublimation have been calculated. Correlations between thermodynamic functions of sublimation and thermophysical properties of the substances and molecular descriptors have been established. The enthalpies of solvation of compounds were calculated using the measured values of enthalpies of sublimation and of standard enthalpies of solution in hexane and buffer

Development of multi-channel high power rectangular RF window for LHCD system employing high temperature vacuum brazing technique

International Nuclear Information System (INIS)

Sharma, P K; Ambulkar, K K; Parmar, P R; Virani, C G; Thakur, A L; Joshi, L M; Nangru, S C

2010-01-01

A 3.7 GHz., 120 kW (pulsed), lower hybrid current drive (LHCD) system is employed to drive non-inductive plasma current in ADITYA tokamak. The rf power is coupled to the plasma through grill antenna and is placed in vacuum environment. A vacuum break between the pressurized transmission line and the grill antenna is achieved with the help of a multi (eight) channel rectangular RF vacuum window. The phasing between adjacent channels of 8-channel window (arranged in two rows) is important for launching lower hybrid waves and each channel should have independent vacuum window so that phase information is retained. The geometrical parameter of the grill antenna, like periodicity (9mm), channel dimensions (cross sectional dimension of 76mm x 7mm), etc. is to be maintained. These design constraint demanded a development of a multi channel rectangular RF vacuum window. To handle rf losses and thermal effects, high temperature vacuum brazing techniques is desired. Based on the above requirements we have successfully developed a multi channel rectangular rf vacuum window employing high temperature vacuum brazing technique. During the development process we could optimize the chemical processing parameters, brazing process parameters, jigs and fixtures for high temperature brazing and leak testing, etc. Finally the window is tested for low power rf performance using VNA. In this paper we would present the development of the said window in detail along with its mechanical, vacuum and rf performances.

Development of multi-channel high power rectangular RF window for LHCD system employing high temperature vacuum brazing technique

Energy Technology Data Exchange (ETDEWEB)

Sharma, P K; Ambulkar, K K; Parmar, P R; Virani, C G; Thakur, A L [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Joshi, L M; Nangru, S C, E-mail: pramod@ipr.res.i [Central Electronics Engineering Research Institute, Pilani, Rajasthan 333 031 (India)

2010-02-01

A 3.7 GHz., 120 kW (pulsed), lower hybrid current drive (LHCD) system is employed to drive non-inductive plasma current in ADITYA tokamak. The rf power is coupled to the plasma through grill antenna and is placed in vacuum environment. A vacuum break between the pressurized transmission line and the grill antenna is achieved with the help of a multi (eight) channel rectangular RF vacuum window. The phasing between adjacent channels of 8-channel window (arranged in two rows) is important for launching lower hybrid waves and each channel should have independent vacuum window so that phase information is retained. The geometrical parameter of the grill antenna, like periodicity (9mm), channel dimensions (cross sectional dimension of 76mm x 7mm), etc. is to be maintained. These design constraint demanded a development of a multi channel rectangular RF vacuum window. To handle rf losses and thermal effects, high temperature vacuum brazing techniques is desired. Based on the above requirements we have successfully developed a multi channel rectangular rf vacuum window employing high temperature vacuum brazing technique. During the development process we could optimize the chemical processing parameters, brazing process parameters, jigs and fixtures for high temperature brazing and leak testing, etc. Finally the window is tested for low power rf performance using VNA. In this paper we would present the development of the said window in detail along with its mechanical, vacuum and rf performances.

A centre-triggered magnesium fuelled cathodic arc thruster uses sublimation to deliver a record high specific impulse

Science.gov (United States)

Neumann, Patrick R. C.; Bilek, Marcela; McKenzie, David R.

2016-08-01

The cathodic arc is a high current, low voltage discharge that operates in vacuum and provides a stream of highly ionised plasma from a solid conducting cathode. The high ion velocities, together with the high ionisation fraction and the quasineutrality of the exhaust stream, make the cathodic arc an attractive plasma source for spacecraft propulsion applications. The specific impulse of the cathodic arc thruster is substantially increased when the emission of neutral species is reduced. Here, we demonstrate a reduction of neutral emission by exploiting sublimation in cathode spots and enhanced ionisation of the plasma in short, high-current pulses. This, combined with the enhanced directionality due to the efficient erosion profiles created by centre-triggering, substantially increases the specific impulse. We present experimentally measured specific impulses and jet power efficiencies for titanium and magnesium fuels. Our Mg fuelled source provides the highest reported specific impulse for a gridless ion thruster and is competitive with all flight rated ion thrusters. We present a model based on cathode sublimation and melting at the cathodic arc spot explaining the outstanding performance of the Mg fuelled source. A further significant advantage of an Mg-fuelled thruster is the abundance of Mg in asteroidal material and in space junk, providing an opportunity for utilising these resources in space.

Aerosol volatility and enthalpy of sublimation of carboxylic acids.

Science.gov (United States)

Salo, Kent; Jonsson, Asa M; Andersson, Patrik U; Hallquist, Mattias

2010-04-08

The enthalpy of sublimation has been determined for nine carboxylic acids, two cyclic (pinonic and pinic acid) and seven straight-chain dicarboxylic acids (C(4) to C(10)). The enthalpy of sublimation was determined from volatility measurements of nano aerosol particles using a volatility tandem differential mobility analyzer (VTDMA) set-up. Compared to the previous use of a VTDMA, this novel method gives enthalpy of sublimation determined over an extended temperature range (DeltaT approximately 40 K). The determined enthalpy of sublimation for the straight-chain dicarboxylic acids ranged from 96 to 161 kJ mol(-1), and the calculated vapor pressures at 298 K are in the range of 10(-6)-10(-3) Pa. These values indicate that dicarboxylic acids can take part in gas-to-particle partitioning at ambient conditions and may contribute to atmospheric nucleation, even though homogeneous nucleation is unlikely. To obtain consistent results, some experimental complications in producing nanosized crystalline aerosol particles were addressed. It was demonstrated that pinonic acid "used as received" needed a further purification step before being suspended as a nanoparticle aerosol. Furthermore, it was noted from distinct differences in thermal properties that aerosols generated from pimelic acid solutions gave two types of particles. These two types were attributed to crystalline and amorphous configurations, and based on measured thermal properties, the enthalpy of vaporization was 127 kJ mol(-1) and that of sublimation was 161 kJ mol(-1). This paper describes a new method that is complementary to other similar methods and provides an extension of existing experimental data on physical properties of atmospherically relevant compounds.

The Kantian theory of the sublime and humanist politics

OpenAIRE

Ayas, Tuğba

2013-01-01

Ankara : The Department of Art, Design and Architecture, İhsan Doğramacı Bilkent University, 2013. Thesis (Ph. D.) -- Bilkent University, 2013. Includes bibliographical refences. The German philosopher Immanuel Kant’s rendition of cosmopolitanism and the sublime have been quite popular separately in various discussions on politics and aesthetics since the late 90s. In today’s political conjuncture the Kantian sublime is consulted in describing the social disasters that had b...

Preparation of W/CuCrZr monoblock test mock-up using vacuum brazing technique

International Nuclear Information System (INIS)

Singh, Kongkham Premjit; Khirwadkar, Samir S.; Bhope, Kedar; Patel, Nikunj; Mokaria, Prakash K.; Mehta, Mayur

2015-01-01

Development of the joining for W/CuCrZr monoblock PFC test mock-up is an interest area in Fusion R and D. W/Cu bimetallic material has prepared using OFHC copper casting approach on the radial surface of W monoblock 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 mins using NiCuMn-37 filler material under deep vacuum environment (10 -6 mbar). Graphite fixtures were used for OFHC copper casting and vacuum brazing experiments. The joint integrity of W/Cu-CuCrZr monoblock mock-up on W/Cu and Cu-CuCrZr has been checked using ultrasonic immersion technique. Micro-structural examination and Spot-wise elemental analysis have been carried out using HR-SEM and EDAX. The results of the experimental work will be discussed in the paper. (author)

Calculational criticality analyses of 10- and 20-MW UF6 freezer/sublimer vessels

International Nuclear Information System (INIS)

Jordan, W.C.

1993-02-01

Calculational criticality analyses have been performed for 10- and 20-MW UF 6 freezer/sublimer vessels. The freezer/sublimers have been analyzed over a range of conditions that encompass normal operation and abnormal conditions. The effects of HF moderation of the UF 6 in each vessel have been considered for uranium enriched between 2 and 5 wt % 235 U. The results indicate that the nuclearly safe enrichments originally established for the operation of a 10-MW freezer/sublimer, based on a hydrogen-to-uranium moderation ratio of 0.33, are acceptable. If strict moderation control can be demonstrated for hydrogen-to-uranium moderation ratios that are less than 0.33, then the enrichment limits for the 10-MW freezer/sublimer may be increased slightly. The calculations performed also allow safe enrichment limits to be established for a 20-NM freezer/sublimer under moderation control

Applications of vacuum technology to novel accelerator problems

International Nuclear Information System (INIS)

Garwin, E.L.

1983-01-01

Vacuum requirements for electron storage rings are most demanding to fulfill, due to the presence of gas desorption caused by large quantities of synchrotron radiation, the very limited area accessible for pumping ports, the need for 10 -9 torr pressures in the ring, and for pressures a decade lower in the interaction regions. Design features of a wide variety of distributed ion sublimation pumps (DIP) developed at SLAC to meet these requirements are discussed, as well as NEG (non-evaporable getter) pumps tested for use in the Large Electron Positron Collider at CERN. Application of DIP to much higher pressures in electron damping rings for the Stanford Linear Collider are discussed

Experimental Studies of Spray Deposition on a Flat Surface in a Vacuum Environment

Science.gov (United States)

Golliher, Eric L.; Yao, S. C.

2015-01-01

Cooling of spacecraft components in the space environment is an on-going research effort. The electronics used in modern spacecraft are always changing and the heat flux is increasing. New, one-of-a-kind missions require new approaches to thermal control. In this research, under vacuum conditions, a pulsed water spray impinged on a small disc, while a high speed data acquisition system recorded the temperature histories of this copper disc. The water droplets froze quickly and accumulated on the disc as the spray continued. After the spray stopped, the frozen water that remained on the disc then sublimated into the vacuum environment and cooled the disc. This paper examines two important aspects of this process: 1) the difference in spray start up and shutdown in a vacuum environment versus in a standard atmospheric pressure environment, and 2) the water utilization efficiency in a vacuum environment due to the effects of drop trajectories and drop bouncing on the surface. Both phenomena play a role during spray cooling in a vacuum. This knowledge should help spacecraft designers plan for spray cooling as an option to cool spacecraft electronics, human metabolic generated heat, and heat from other sources.

Calibration technique for radiation measurements in vacuum ultraviolet - soft x-ray region

International Nuclear Information System (INIS)

Mizui, Jun-ichi

1986-05-01

This is a collection of the papers presented at the workshop on ''Calibration Technique for Radiation Measurements in Vacuum Ultraviolet - Soft X-ray Region'' held at the Institute of Plasma Physics, Nagoya University, on December 19 - 20, 1985, under the Collaborating Research Program at the Institute. The following topics were discussed at the workshop: the needs for the calibration of plasma diagnostic devices, present status of the calibration technique, use of the Synchrotron Orbit Radiations for radiometry, and others. (author)

An investigation on the mechanism of sublimed DHB matrix on molecular ion yields in SIMS imaging of brain tissue.

Science.gov (United States)

Dowlatshahi Pour, Masoumeh; Malmberg, Per; Ewing, Andrew

2016-05-01

We have characterized the use of sublimation to deposit matrix-assisted laser desorption/ionization (MALDI) matrices in secondary ion mass spectrometry (SIMS) analysis, i.e. matrix-enhanced SIMS (ME-SIMS), a common surface modification method to enhance sensitivity for larger molecules and to increase the production of intact molecular ions. We use sublimation to apply a thin layer of a conventional MALDI matrix, 2,5-dihydroxybenzoic acid (DHB), onto rat brain cerebellum tissue to show how this technique can be used to enhance molecular yields in SIMS while still retaining a lateral resolution around 2 μm and also to investigate the mechanism of this enhancement. The results here illustrate that cholesterol, which is a dominant lipid species in the brain, is decreased on the tissue surface after deposition of matrix, particularly in white matter. The decrease of cholesterol is followed by an increased ion yield of several other lipid species. Depth profiling of the sublimed rat brain reveals that the lipid species are de facto extracted by the DHB matrix and concentrated in the top most layers of the sublimed matrix. This extraction/concentration of lipids directly leads to an increase of higher mass lipid ion yield. It is also possible that the decrease of cholesterol decreases the potential suppression of ion yield caused by cholesterol migration to the tissue surface. This result provides us with significant insights into the possible mechanisms involved when using sublimation to deposit this matrix in ME-SIMS.

The oxidation kinetics for sublimates formed during niobium electron-beam remelting

International Nuclear Information System (INIS)

Chumarev, V.M.; Gulyaeva, R.I.; Mar'evich, V.P.; Upolovnikova, A.G.; Udoeva, L.Yu.

2003-01-01

The oxidation of sublimates of Nb-Al electron beam remelting is investigated under conditions of isothermal and continuous heating in the air. It is stated that basic oxidation products are niobium and aluminium oxides, as well as aluminium niobates of variable composition of Al 2 O 3 · mNb 2 O 5 . The more aluminium enriched sublimates possess an increased resistance to oxidation. Formed in sublimates NbAl 3 intermetallic compound features the highest heat resistance. Oxidation parameters are determined by the method of nonisothermic kinetics. It is noted that the running processes exhibit a multistage nature and are limited by internal diffusion [ru

Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

Directory of Open Access Journals (Sweden)

W. Thiery

2012-08-01

Full Text Available In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance during 2009 and 2010. Comparison to three other AWSs in Dronning Maud Land with 11 to 13 yr of observations shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23% of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (17 mm w.e. yr⁻¹ compared to 42 mm w.e. yr⁻¹ at Svea Cross and 52 mm w.e. yr⁻¹ at Wasa/Aboa. This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and, therefore, on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. This wind speed class turns out to contribute most to the total snowdrift sublimation mass flux, given its ability to lift a high number of particles while still allowing for considerable undersaturation.

Mechanism and kinetics for ammonium dinitramide (ADN) sublimation: a first-principles study.

Science.gov (United States)

Zhu, R S; Chen, Hui-Lung; Lin, M C

2012-11-08

The mechanism for sublimation of NH(4)N(NO(2))(2) (ADN) has been investigated quantum-mechanically with generalized gradient approximation plane-wave density functional theory calculations; the solid surface is represented by a slab model and the periodic boundary conditions are applied. The calculated lattice constants for the bulk ADN, which were found to consist of NH(4)(+)[ON(O)NNO(2)](-) units, instead of NH(4)(+)[N(NO(2))(2)](-), agree quite well with experimental values. Results show that three steps are involved in the sublimation/decomposition of ADN. The first step is the relaxation of the surface layer with 1.6 kcal/mol energy per NH(4)ON(O)NNO(2) unit; the second step is the sublimation of the surface layer to form a molecular [NH(3)]-[HON(O)NNO(2)] complex with a 29.4 kcal/mol sublimation energy, consistent with the experimental observation of Korobeinichev et al. (10) The last step is the dissociation of the [H(3)N]-[HON(O)NNO(2)] complex to give NH(3) and HON(O)NNO(2) with the dissociation energy of 13.9 kcal/mol. Direct formation of NO(2) (g) from solid ADN costs a much higher energy, 58.3 kcal/mol. Our calculated total sublimation enthalpy for ADN(s) → NH(3)(g) + HON(O)NNO(2)) (g), 44.9 kcal/mol via three steps, is in good agreement with the value, 42.1 kcal/mol predicted for the one-step sublimation process in this work and the value 44.0 kcal/mol computed by Politzer et al. (11) using experimental thermochemical data. The sublimation rate constant for the rate-controlling step 2 can be represented as k(sub) = 2.18 × 10(12) exp (-30.5 kcal/mol/RT) s(-1), which agrees well with available experimental data within the temperature range studied. The high pressure limit decomposition rate constant for the molecular complex H(3)N···HON(O)NNO(2) can be expressed by k(dec) = 3.18 × 10(13) exp (-15.09 kcal/mol/RT) s(-1). In addition, water molecules were found to increase the sublimation enthalpy of ADN, contrary to that found in the ammonium

Vapor pressures and sublimation enthalpies of novel bicyclic heterocycle derivatives

International Nuclear Information System (INIS)

Blokhina, Svetlana V.; Ol’khovich, Marina V.; Sharapova, Angelica V.; Perlovich, German L.; Proshin, Alexey N.

2014-01-01

Highlights: • The vapor pressures of novel bicyclo-derivatives of amine were measured. • Thermodynamic functions of sublimation were calculated. • The influence of substituent structure and chemical nature on the vapor pressure was studied. -- Abstract: The vapor pressures of five novel bicyclic heterocycle derivatives were measured over the temperature 341.15 to 396.15 K using the transpiration method by means of an inert gas carrier. From these results the standard enthalpies and Gibbs free energies of sublimation at the temperature 298.15 K were calculated. The effects of alkyl- and chloro-substitutions on changes in the thermodynamic functions have been investigated. Quantitative structure–property relationship on the basis HYBOT physico-chemical descriptors for biologically active compounds have been developed to predict the sublimation enthalpies and Gibbs free energies of the compounds studied

Los cuerpos sublimes

Directory of Open Access Journals (Sweden)

Juan Pablo Zangara

2015-09-01

Full Text Available La narración de crímenes en la prensa de masas y las pantallas parece constituir una versión contemporánea del magnetismo según Edgar Allan Poe. La estetización mediática (ya no la información de una serie reciente de feminicidios permite reconocer una cierta lógica de lo sublime como clave de la producción de noticias-mercancías. En su variante clásica, la ficción policial funciona como una matriz ideológica decisiva de la enunciación periodística.

TRIGGERING SUBLIMATION-DRIVEN ACTIVITY OF MAIN BELT COMETS

Energy Technology Data Exchange (ETDEWEB)

Haghighipour, N. [Institute for Astronomy, University of Hawaii-Manoa, Honolulu, HI 96825 (United States); Maindl, T. I.; Dvorak, R. [Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Schäfer, C. [Institut für Astronomie und Astrophysik, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen (Germany); Speith, R., E-mail: nader@ifa.hawaii.edu [Physikalisches Institut, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen (Germany)

2016-10-10

It has been suggested that the comet-like activity of main belt comets (MBCs) is due to the sublimation of sub-surface water–ice that has been exposed as a result of their surfaces being impacted by meter-sized bodies. We have examined the viability of this scenario by simulating impacts between meter-sized and kilometer-sized objects using a smooth particle hydrodynamics approach. Simulations have been carried out for different values of the impact velocity and impact angle, as well as different target material and water-mass fractions. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m, suggesting that if the activation of MBCs is due to the sublimation of sub-surface water–ice, this ice has to exist no deeper than a few meters from the surface. Results also show that ice exposure occurs in the bottom and on the interior surface of impact craters, as well as on the surface of the target where some of the ejected icy inclusions are re-accreted. While our results demonstrate that the impact scenario is indeed a viable mechanism to expose ice and trigger the activity of MBCs, they also indicate that the activity of the current MBCs is likely due to ice sublimation from multiple impact sites and/or the water contents of these objects (and other asteroids in the outer asteroid belt) is larger than the 5% that is traditionally considered in models of terrestrial planet formation, providing more ice for sublimation. We present the details of our simulations and discuss their results and implications.

Transient thermal protection of film covering circular aperture by sublimation and weak decomposition

Energy Technology Data Exchange (ETDEWEB)

Havstad, Mark A.; Miles, Robin R.; Hsieh, Henry, E-mail: hsieh6@llnl.gov

2015-03-15

Highlights: • Precise sublimating layers can provide protection in transient thermal environments. • Sensitivity analysis shows that the uncertainty in properties has modest influence. • It is likely that methane layers are a good choice for IFE targets. - Abstract: Unwanted heating of sensitive surfaces in harsh thermal environments can be prevented by precise application of sacrificial materials such as sublimation layers and pyrolyzing films. The use of sublimation for the protection of circular polyimide membranes subjected to brief (∼100 ms) heating by infrared radiation and hot (6000 K) inert gas convection is analyzed. Selection of sublimation material and sublimation layer and membrane thickness is considered with emphasis on providing sufficient thermal protection yet negligible unwanted material remaining at the end of a specified heating period. Though the analysis here is general, the motivation is protection of the polyimide films covering the laser entrance holes on IFE (inertial fusion energy) hohlraums being injected into the hot gas (xenon) protecting IFE reactor chambers. Both one and two dimensional thermal models are used to develop a robust thermal concept. Sensitivity analyses (SA) methods are exercised to show where the design may be vulnerable and which input parameters have the greatest effect on performance and likelihood of success. For the design and conditions considered, methane sublimating layers are probably preferred over xenon or pentane.

Experimental Analysis of Sublimation Dynamics for Buried Glacier Ice in Beacon Valley, Antarctica

Science.gov (United States)

Ehrenfeucht, S.; Dennis, D. P.; Marchant, D. R.

2017-12-01

The age of the oldest known buried ice in Beacon Valley, McMurdo Dry Valleys (MDV) Antarctica is a topic of active debate due to its implications for the stability of the East Antarctic Ice Sheet. Published age estimates range from as young as 300 ka to as old as 8.1 Ma. In the upland MDV, ablation occurs predominantly via sublimation. The relict ice in question (ancient ice from Taylor Glacier) lies buried beneath a thin ( 30-70 cm) layer of sublimation till, which forms as a lag deposit as underlying debris-rich ice sublimes. As the ice sublimates, the debris held within the ice accumulates slowly on the surface, creating a porous boundary between the buried-ice surface and the atmosphere, which in turn influences gas exchange between the ice and the atmosphere. Additionally, englacial debris adds several salt species that are ultimately concentrated on the ice surface. It is well documented the rate of ice sublimation varies as a function of overlying till thickness. However, the rate-limiting dynamics under varying environmental conditions, including the threshold thicknesses at which sublimation is strongly retarded, are not yet defined. To better understand the relationships between sublimation rate, till thickness, and long-term surface evolution, we build on previous studies by Lamp and Marchant (2017) and evaluate the role of till thickness as a control on ice loss in an environmental chamber capable of replicating the extreme cold desert conditions observed in the MDV. Previous work has shown that this relationship exhibits exponential decay behavior, with sublimation rate significantly dampened under less than 10 cm of till. In our experiments we pay particular attention to the effect of the first several cm of till in order to quantify the dynamics that govern the transition from bare ice to debris-covered ice. We also examine this transition for various forms of glacier ice, including ice with various salt species.

Applications of vacuum technology to novel accelerator problems

Energy Technology Data Exchange (ETDEWEB)

Garwin, E.L.

1983-01-01

Vacuum requirements for electron storage rings are most demanding to fulfill, due to the presence of gas desorption caused by large quantities of synchrotron radiation, the very limited area accessible for pumping ports, the need for 10/sup -9/ torr pressures in the ring, and for pressures a decade lower in the interaction regions. Design features of a wide variety of distributed ion sublimation pumps (DIP) developed at SLAC to meet these requirements are discussed, as well as NEG (non-evaporable getter) pumps tested for use in the Large Electron Positron Collider at CERN. Application of DIP to much higher pressures in electron damping rings for the Stanford Linear Collider are discussed.

Ad infinitum: implicaciones de lo sublime en la contemporaneidad

Directory of Open Access Journals (Sweden)

Miguel Ángel Gaete Cáceres

2014-12-01

Full Text Available El presente texto es un estudio que ofrece una revisión crítica al concepto de lo sublime basándose en la teorización clásica de esta idea, es decir, la adjudicada a Longino, Edmund Burke e Immanuel Kant. A partir de aquí, se intentará descubrir la presencia de lo sublime como un factor relevante en la configuración cultural del mundo contemporáneo, pasando por su presencia innegable en el arte de las vanguardias o en la concepción de la Naturaleza y el entorno. Finalmente, el objetivo central de este escrito es demostrar como lo sublime ofrece también una alternativa para comprender el problema de "lo infinito" y "lo ilimitado" en el marco de las tecnologías, la eclosión de las grandes ciudades y su filtración en el sustrato retórico del capitalismo, ofreciendo así una vía diferente en el estudio de este tema clásico de la estética.

On the use of semiempirical models of (solid + supercritical fluid) systems to determine solid sublimation properties

International Nuclear Information System (INIS)

Tabernero, Antonio; Martin del Valle, Eva M.; Galan, Miguel A.

2011-01-01

Research highlights: → We propose a method to determine sublimation properties of solids. → Low deviations were produced calculating sublimation enthalpies and pressures. → It is a required step to determine the vaporization enthalpy of the solid. → It is possible to determine solid properties using semiempirical models solid-SCF. - Abstract: Experimental solubility data of solid-supercritical fluids have significantly increased in the last few years, and semiempirical models are emerging as one of the best choices to fit this type of data. This work establishes a methodology to calculate sublimation pressures using this type of equations. It requires the use of Bartle's equation to model equilibria data solid-supercritical fluids with the aim of determining the vaporization enthalpy of the compound. Using this method, low deviations were obtained by calculating sublimation pressures and sublimation enthalpies. The values of the sublimation pressures were subsequently used to successfully model different multiphasic equilibria, as solid-supercritical fluids and solid-solvent-supercritical fluids with the Peng-Robinson equation of state (without considering the sublimation pressure as an adjustable parameter). On the other hand, the sublimation pressures were also used to calculate solid sublimation properties and acetaminophen solvation properties in some solvents. Also, solubility data solid-supercritical fluids from 62 pharmaceuticals were fitted with different semiempirical equations (Chrastil, Kumar-Johnston and Bartle models) in order to present the values of solvation enthalpies in sc-CO 2 and vaporization enthalpies for these compounds. All of these results highlight that semiempirical models can be used for any other purpose as well as modeling (solid + supercritical fluids) equilibria.

Mimeses do sublime: a recepção de Kant pelo Romantismo e pelo Expressionismo Mimesis of sublime: the Romantism and Expressionism reception of Kant

Directory of Open Access Journals (Sweden)

Priscila Rossinetti Rufinoni

2007-01-01

Full Text Available Partindo das analises do criticismo kantiano, este texto investiga as concepções romântica e moderna de sublime e de imaginação. Se, por um lado, a concepção romântica inaugura o mundo moderno, por outro, a expressionista mostra os limites dessa mesma modernidade. Para ambas, entretanto, a Crítica do Juízo de Kant é o âmbito privilegiado no qual podemos precisar as distinções.Starting from the analysis of the Kantian criticism, this text investigates the romantic and the modern conceptions of sublime and imagination. On the one hand, the romantic conceptions of sublime inaugurate the modern world. On the other hand, the expressionist conceptions show the confines of this world. The Critique of Judgment is the very locus where such distinctions can be drawn with precision.

Studies of CdS/CdTe interface: Comparison of CdS films deposited by close space sublimation and chemical bath deposition techniques

Energy Technology Data Exchange (ETDEWEB)

Han, Jun-feng, E-mail: pkuhjf@bit.edu.cn [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Institute of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Fu, Gan-hua; Krishnakumar, V.; Schimper, Hermann-Josef [Institute of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); Liao, Cheng [Department of Physics, Peking University, Beijing 100871 (China); Jaegermann, Wolfram [Institute of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt (Germany); Besland, M.P. [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France)

2015-05-01

The CdS layers were deposited by two different methods, close space sublimation (CSS) and chemical bath deposition (CBD) technique. The CdS/CdTe interface properties were investigated by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The TEM images showed a large CSS-CdS grain size in the range of 70-80 nm. The interface between CSS-CdS and CdTe were clear and sharp, indicating an abrupt hetero-junction. On the other hand, CBD-CdS layer had much smaller grain size in the 5-10 nm range. The interface between CBD-CdS and CdTe was not as clear as CSS-CdS. With the stepwise coverage of CdTe layer, the XPS core levels of Cd 3d and S 2p in CSS-CdS had a sudden shift to lower binding energies, while those core levels shifted gradually in CBD-CdS. In addition, XPS depth profile analyses indicated a strong diffusion in the interface between CBD-CdS and CdTe. The solar cells prepared using CSS-CdS yielded better device performance than the CBD-CdS layer. The relationships between the solar cell performances and properties of CdS/CdTe interfaces were discussed. - Highlights: • Studies of CdS deposited by close space sublimation and chemical bath deposition • An observation of CdS/CdTe interface by transmission electron microscope • A careful investigation of CdS/CdTe interface by X ray photoelectron spectra • An easier diffusion at the chemical bath deposition CdS and CdTe interface.

Of images and ills. Uses and malaises of sublimation

Directory of Open Access Journals (Sweden)

Georges Didi-Huberman

2017-05-01

Full Text Available This text is published as postface to the new edition of Invention de l'hystérie. Charcot et l’iconographie photographique de l’hystérie (Macula, Paris, 2012, pp. 364-405 with the title Des images et des maux. It’s also the full version of the lecture organized by the Association Psychanalytique de France (September 24, 2011, entitled L’Usage de la sublimation. Starting from some considerations on his first book, the Author examines limits and potentials of the notion of sublimation in reference with art and artistic creation, and suggests a different way to approach it.

Sublimation-Induced Shape Evolution of Silver Cubes

KAUST Repository

Ding, Yong; Fan, Fengru; Tian, Zhongqun; Wang, Zhong Lin

2009-01-01

The heat is on: Surface sublimation and shape transformation of silver cubes, enclosed by {100} surfaces and about 100nm in size, are examined by in situ transmission electron microscopy (see picture). High-index surfaces, such as {110}, of face

El Silencio de la Sirena: lo Sublime en Alejandra Pizarnik

Directory of Open Access Journals (Sweden)

Julieta Lerman

2012-12-01

Full Text Available Algunas poéticas de las décadas del cincuenta y del sesenta parecerían constituirse en torno a un vacío, un silencio que a veces inspira la palabra poética y otras veces la aborta. Esa ambigüedad, característica de la poética de Alejandra Pizarnik, podemos entenderla como una “reedición” de la estética de lo sublime. Lo sublime es un concepto estético-filosófico que plantearon filósofos como Inmanuel Kant y Edmund Burke para pensar el arte romántico y, en el siglo XX, otros autores como Jean-François Lyotard, lo retomaron para analizar el arte de vanguardia. Así, lo sublime nos permite repensar la poética de Pizarnik en sus coincidencias y oposiciones a otras de la tradición moderna (como la de Charles Baudelaire o de las vanguardias latinoamericanas (como Oliverio Girondo y Vicente Huidobro.

Laboratory model study of newly deposited dredger fills using improved multiple-vacuum preloading technique

Directory of Open Access Journals (Sweden)

Jingjin Liu

2017-10-01

Full Text Available Problems continue to be encountered concerning the traditional vacuum preloading method in field during the treatment of newly deposited dredger fills. In this paper, an improved multiple-vacuum preloading method was developed to consolidate newly dredger fills that are hydraulically placed in seawater for land reclamation in Lingang Industrial Zone of Tianjin City, China. With this multiple-vacuum preloading method, the newly deposited dredger fills could be treated effectively by adopting a novel moisture separator and a rapid improvement technique without sand cushion. A series of model tests was conducted in the laboratory for comparing the results from the multiple-vacuum preloading method and the traditional one. Ten piezometers and settlement plates were installed to measure the variations in excess pore water pressures and moisture content, and vane shear strength was measured at different positions. The testing results indicate that water discharge–time curves obtained by the traditional vacuum preloading method can be divided into three phases: rapid growth phase, slow growth phase, and steady phase. According to the process of fluid flow concentrated along tiny ripples and building of larger channels inside soils during the whole vacuum loading process, the fluctuations of pore water pressure during each loading step are divided into three phases: steady phase, rapid dissipation phase, and slow dissipation phase. An optimal loading pattern which could have a best treatment effect was proposed for calculating the water discharge and pore water pressure of soil using the improved multiple-vacuum preloading method. For the newly deposited dredger fills at Lingang Industrial Zone of Tianjin City, the best loading step was 20 kPa and the loading of 40–50 kPa produced the highest drainage consolidation. The measured moisture content and vane shear strength were discussed in terms of the effect of reinforcement, both of which indicate

Recommended sublimation pressure and enthalpy of benzene

Czech Academy of Sciences Publication Activity Database

Růžička, K.; Fulem, Michal; Červinka, C.

2014-01-01

Roč. 68, Jan (2014), s. 40-47 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal - gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014

Debate on sublime in the end of 18th century: Burke, Kant, Schiller

Directory of Open Access Journals (Sweden)

Jeremić-Molnar Dragana

2009-01-01

Full Text Available In the article the authors are examining three positions within the 18th Century aesthetic discussion on the sublime - Edmund Burke's, Immanuel Kant's and Friedrich Schiller's. They are also trying to reconstruct the political backgrounds of each of this theoretical positions: old regime conservatism (Burke, republican liberalism (Schiller and romantic longing for the 'third way' (Kant. The most sophisticated and mature theory of sublime is found in Schiller's aesthetic works, especially in those following his disappointment in French Revolution, in which the relationship between sublime and paradoxes of historical violence is most thoroughly reflected.

Blowing snow sublimation and transport over Antarctica from 11 years of CALIPSO observations

Directory of Open Access Journals (Sweden)

S. P. Palm

2017-11-01

Full Text Available Blowing snow processes commonly occur over the earth's ice sheets when the 10 m wind speed exceeds a threshold value. These processes play a key role in the sublimation and redistribution of snow thereby influencing the surface mass balance. Prior field studies and modeling results have shown the importance of blowing snow sublimation and transport on the surface mass budget and hydrological cycle of high-latitude regions. For the first time, we present continent-wide estimates of blowing snow sublimation and transport over Antarctica for the period 2006–2016 based on direct observation of blowing snow events. We use an improved version of the blowing snow detection algorithm developed for previous work that uses atmospheric backscatter measurements obtained from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization lidar aboard the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite. The blowing snow events identified by CALIPSO and meteorological fields from MERRA-2 are used to compute the blowing snow sublimation and transport rates. Our results show that maximum sublimation occurs along and slightly inland of the coastline. This is contrary to the observed maximum blowing snow frequency which occurs over the interior. The associated temperature and moisture reanalysis fields likely contribute to the spatial distribution of the maximum sublimation values. However, the spatial pattern of the sublimation rate over Antarctica is consistent with modeling studies and precipitation estimates. Overall, our results show that the 2006–2016 Antarctica average integrated blowing snow sublimation is about 393 ± 196 Gt yr−1, which is considerably larger than previous model-derived estimates. We find maximum blowing snow transport amount of 5 Mt km−1 yr−1 over parts of East Antarctica and estimate that the average snow transport from continent to ocean is about 3.7 Gt yr−1. These

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

International Nuclear Information System (INIS)

Bhusan, K.G.

2008-01-01

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

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

International Nuclear Information System (INIS)

Cheng Shaoyong; Xiu Shixin; Wang Jimei; Shen Zhengchao

2006-01-01

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

Distributed modelling of climate change impacts on snow sublimation in Northern Mongolia

Directory of Open Access Journals (Sweden)

L. Menzel

2009-08-01

Full Text Available Sublimation of snow is an important factor of the hydrological cycle in Mongolia and is likely to increase according to future climate projections. In this study the hydrological model TRAIN was used to assess spatially distributed current and future sublimation rates based on interpolated daily data of precipitation, air temperature, air humidity, wind speed and solar radiation. An automated procedure for the interpolation of the input data is provided. Depending on the meteorological parameter and the data availability for the individual days, the most appropriate interpolation method is chosen automatically from inverse distance weighting, Ordinary Least Squares interpolation, Ordinary or Universal Kriging. Depending on elevation simulated annual sublimation in the period 1986–2006 was 23 to 35 mm, i.e. approximately 80% of total snowfall. Moreover, future climate projections for 2071–2100 of ECHAM5 and HadCM3, based on the A1B emission scenario of the Intergovernmental Panel on Climate Change, were analysed with TRAIN. In the case of ECHAM5 simulated sublimation increases by up to 17% (26...41 mm while it remains at the same level for HadCM3 (24...34 mm. The differences are mainly due to a distinct increase in winter precipitation for ECHAM5. Simulated changes of the all-season hydrological conditions, e.g. the sublimation-to-precipitation ratio, were ambiguous due to diverse precipitation patterns derived by the global circulation models.

Measured and modelled sublimation on the tropical Glaciar Artesonraju, Perú

OpenAIRE

Winkler , M.; Juen , I.; Mölg , T.; Wagnon , Patrick; Gómez , J.; Kaser , G.

2009-01-01

Sublimation plays a decisive role in the surface energy and mass balance of tropical glaciers. During the dry season (May–September) low specific humidity and high surface roughness favour the direct transition from ice to vapour and drastically reduce the energy available for melting. However, field measurements are scarce and little is known about the performance of sublimation parameterisations in glacier mass balance and runoff models.

During 15 days in August 2005 su...

Measuring Enthalpy of Sublimation of Volatiles by Means of Piezoelectric Crystal Microbalances

Science.gov (United States)

Dirri, Fabrizio; Palomba, Ernesto; Longobardo, Andrea; Zampetti, Emiliano

2017-12-01

Piezoelectric Crystal Microbalances (PCM's) are widely used to study the chemical processes involving volatile compounds in any environment, such as condensation process. Since PCM's are miniaturized sensor, they are very suitable for planetary in situ missions, where can be used to detect and to measure the mass amount of astrobiologically significant compounds, such as water and organics. This work focuses on the realization and testing of a new experimental setup, able to characterize volatiles which can be found in a planetary environment. In particular the enthalpy of sublimation of some dicarboxylic acids has been measured. The importance of dicarboxylic acids in planetology and astrobiology is due to the fact that they have been detected in carbonaceous chondritic material (e.g. Murchinson), among the most pristine material present in our Solar System. In this work, a sample of acid was heated in an effusion cell up to its sublimation. For a set of temperatures (from 30 °C to 75 °C), the deposition rate on the PCM surface has been measured. From these measurements, it has been possible to infer the enthalpy of sublimation of Adipic acid, i.e. ΔH = 141.6 ± 0.8 kJ/mol and Succinic acid, i.e. ΔH = 113.3 ± 1.3 kJ/mol. This technique has so demonstrated to be a good choice to recognise a single compound or a mixture (with an analysis upstream) even if some improvements concerning the thermal stabilization of the system will be implemented in order to enhance the results' accuracy. The experiment has been performed in support of the VISTA (Volatile In Situ Thermogravimetry Analyzer) project, which is included in the scientific payload of the ESA MarcoPolo-R mission study.

Experiments On Sublimating Carbon Dioxide Ice And Implications For Contemporary Surface Processes On Mars.

Science.gov (United States)

Mc Keown, L E; Bourke, M C; McElwaine, J N

2017-10-27

Carbon dioxide is Mars' primary atmospheric constituent and is an active driver of Martian surface evolution. CO 2 ice sublimation mechanisms have been proposed for a host of features that form in the contemporary Martian climate. However, there has been very little experimental work or quantitative modelling to test the validity of these hypotheses. Here we present the results of the first laboratory experiments undertaken to investigate if the interaction between sublimating CO 2 ice blocks and a warm, porous, mobile regolith can generate features similar in morphology to those forming on Martian dunes today. We find that CO 2 sublimation can mobilise grains to form (i) pits and (ii) furrows. We have documented new detached pits at the termini of linear gullies on Martian dunes. Based on their geomorphic similarity to the features observed in our laboratory experiments, and on scaling arguments, we propose a new hypothesis that detached pits are formed by the impact of granular jets generated by sublimating CO 2 . We also study the erosion patterns formed underneath a sublimating block of CO 2 ice and demonstrate that these resemble furrow patterns on Mars, suggesting similar formation mechanisms.

Proceedings of the 5th meeting on ultra high vacuum techniques for accelerators and storage rings

International Nuclear Information System (INIS)

Horikoshi, Gen-ichi

1984-08-01

This is the proceedings of the 5th meeting on UHV Techniques for Accelerators and Storage Rings held at KEK, March 26-27, 1984. More than 110 vacuum scientists attended the meeting, and 23 reports were presented. Main subjects were, of course, concerning with the vacuum systems for large accelerators and plasma devices under planning or construction in Japan. At the same time, many reports on the general problems of vacumm science were also presented. The subjects of these reports were outgassing phenomenon, surface problems, new type UHV pumps and others. (author)

Nietzsche's View of Sublimation in the Educational Process

Science.gov (United States)

Sharp, Ann Margaret

1975-01-01

Article outlined Nietzsche's beliefs on the primary aim of education, the conscious production of the free man through the process of sublimation, the active redirecting of one's life energy in the service of creativity. (Editor/RK)

Baking system for vacuum components in INDUS-2

International Nuclear Information System (INIS)

Bhange, Nilesh J.; Bhatnagar, Prateek; Shukla, S.K.

2005-01-01

Optimized bake-out procedures are very important for the overall reliability of vacuum system. In this process the UHV components like Sputter ion pump (SIP), Titanium sublimation pump (TSP) are subjected to temperature rise for sufficiently long period of time. Baking is necessary for obtaining low out gassing rates. In order to provide controlled baking of UHV (Ultra High Vacuum) components for INDUS-II an intelligent ON/OFF control system was needed. For that purpose distributed control system was suitable. For fulfillment of this need modular baking system was developed. This system contains Temperature controller unit (TCU), Pressure Monitoring Unit (PMU), and Temperature control and pressure Monitoring Interface Software (TCPMIS). Each TCU is an eight channel temperature controlling unit. PMU is eight channel pressure monitoring unit to which analog data from gauges like Penning, BA Gauge controllers is given. TCPMIS is a user interface software developed for, controlling up to 5 TCU's. In this way 40 channel temperature control, data logging of 40 channel temperature and logging of eight channel pressures was realized. The present paper describes details about computer controlled baking system. (author)

LLNL Tandem Mirror Experiment (TMX) upgrade vacuum system

International Nuclear Information System (INIS)

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

1981-01-01

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

Structure-property relationships in halogenbenzoic acids: Thermodynamics of sublimation, fusion, vaporization and solubility.

Science.gov (United States)

Zherikova, Kseniya V; Svetlov, Aleksey A; Kuratieva, Natalia V; Verevkin, Sergey P

2016-10-01

Temperature dependences of vapor pressures for 2-, 3-, and 4-bromobenzoic acid, as well as for five isomeric bromo-methylbenzoic acids were studied by the transpiration method. Melting temperatures and enthalpies of fusion for all isomeric bromo-methylbenzoic acids and 4-bromobenzoic acid were measured with a DSC. The molar enthalpies of sublimation and vaporization were derived. These data together with results available in the literature were collected and checked for internal consistency using a group-additivity procedure and results from X-ray structural diffraction studies. Specific (hydrogen bonding) interactions in the liquid and in the crystal phase of halogenbenzoic acids were quantified based on experimental values of vaporization and sublimation enthalpies. Structure-property correlations of solubilities of halogenobenzoic acids with sublimation pressures and sublimation enthalpies were developed and solubilities of bromo-benzoic acids were estimated. These new results resolve much of the ambiguity in the available thermochemical and solubility data on bromobenzoic acids. The approach based on structure property correlations can be applied for the assessment of water solubility of sparingly soluble drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Particle creation during vacuum decay

International Nuclear Information System (INIS)

Rubakov, V.A.

1984-01-01

The hamiltonian approach is developed with regard to the problem of particle creation during the tunneling process, leading to the decay of the false vacuum in quantum field theory. It is shown that, to the lowest order in (h/2π), the particle creation is described by the euclidean Schroedinger equation in an external field of a bounce. A technique for solving this equation is developed in an analogy to the Bogoliubov transformation technique, in the theory of particle creation in the presence of classical background fields. The technique is illustrated by two examples, namely, the particle creation during homogeneous vacuum decay and during the tunneling process leading to the materialization of the thin-wall bubble of a new vacuum in the metastable one. The curious phenomenon of intensive particle annihilation during vacuum decay is discussed and explicitly illustrated within the former example. The non-unitary extension of the Bogoliubov u, v transformations is described in the appendix. (orig.)

Microstructure characteristics of vacuum glazing brazing joints using laser sealing technique

Science.gov (United States)

Liu, Sixing; Yang, Zheng; Zhang, Jianfeng; Zhang, Shanwen; Miao, Hong; Zhang, Yanjun; Zhang, Qi

2018-05-01

Two pieces of plate glass were brazed into a composite of glazing with a vacuum chamber using PbO-TiO2-SiO2-RxOy powder filler alloys to develop a new type of vacuum glazing. The brazing process was carried out by laser technology. The interface characteristics of laser brazed joints formed between plate glass and solder were investigated using optical microscope, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The results show that the inter-diffusion of Pb/Ti/Si/O elements from the sealing solder toward the glass and O/Al/Si elements from the glass toward the solder, resulting in a reaction layer in the brazed joints. The microstructure phases of PbTiO3, AlSiO, SiO2 and PbO in the glass/solder interface were confirmed by XRD analysis. The joining of the sealing solder to the glass was realized by the reaction products like fibrous structures on interface, where the wetting layer can help improve the bonding performance and strength between the sealing solder and the plate glass during the laser brazing process.

El Silencio de la Sirena: lo Sublime en Alejandra Pizarnik

Directory of Open Access Journals (Sweden)

Julieta Lerman

2012-03-01

Full Text Available http://dx.doi.org/10.5007/1984-784X.2012v12n17p85 Algunas poéticas de las décadas del cincuenta y del sesenta parecerían constituirse en torno a un vacío, un silencio que a veces inspira la palabra poética y otras veces la aborta. Esa ambigüedad, característica de la poética de Alejandra Pizarnik, podemos entenderla como una “reedición” de la estética de lo sublime. Lo sublime es un concepto estético-filosófico que plantearon filósofos como Inmanuel Kant y Edmund Burke para pensar el arte romántico y, en el siglo XX, otros autores como Jean-François Lyotard, lo retomaron para analizar el arte de vanguardia. Así, lo sublime nos permite repensar la poética de Pizarnik en sus coincidencias y oposiciones a otras de la tradición moderna (como la de Charles Baudelaire o de las vanguardias latinoamericanas (como Oliverio Girondo y Vicente Huidobro.

Deposition techniques for the preparation of thin film nuclear targets

International Nuclear Information System (INIS)

Muggleton, A.H.F.

1987-07-01

This review commences with a brief description of the basic principles that regulate vacuum evaporation and the physical processes involved in thin film formation, followed by a description of the experimental methods used. The principle methods of heating the evaporant are detailed and the means of measuring and controlling the film thickness are elucidated. Types of thin film nuclear targets are considered and various film release agents are listed. Thin film nuclear target behaviour under ion-bombardment is described and the dependence of nuclear experimental results upon target thickness and uniformity is outlined. Special problems associated with preparing suitable targets for lifetime measurements are discussed. The causes of stripper-foil thickening and breaking under heavy-ion bombardment are considered. A comparison is made between foils manufactured by a glow discharge process and those produced by vacuum sublimation. Consideration is given to the methods of carbon stripper-foil manufacture and to the characteristics of stripper-foil lifetimes are considered. Techniques are described that have been developed for the fabrication of special targets, both from natural and isotopically enriched material, and also of elements that are either chemically unstable, or thermally unstable under irradiation. The reduction of metal oxides by the use of hydrogen or by utilising a metallothermic technique, and the simultaneous evaporation of reduced rare earth elements is described. A comprehensive list of the common targets is presented

"Back-fire to lust": G. Stanley Hall, sex-segregated schooling, and the engine of sublimation.

Science.gov (United States)

Graebner, William

2006-08-01

G. Stanley Hall was an advocate of sex-segregated schooling long after most Americans had accepted coeducation. His position was based in part on personal experience: observations of his father and mother, a repressed and guilt-ridden boyhood sexuality, and his conviction that his own career success was a product of sublimated sexual desire, of erotic energy converted into mental energy. Hall theorized that coeducation put sublimation at risk, and that sex-segregated schools, by contributing to proper gendered development and by prolonging and sublimating the sexual tensions of adolescence, would produce social progress.

Sublimation-Induced Shape Evolution of Silver Cubes

KAUST Repository

Ding, Yong

2009-12-18

The heat is on: Surface sublimation and shape transformation of silver cubes, enclosed by {100} surfaces and about 100nm in size, are examined by in situ transmission electron microscopy (see picture). High-index surfaces, such as {110}, of face-centered cubic metals are more stable when the temperature is close to the melting point.

An Enhanced Vacuum Cure Technique for On-Aircraft Repair of Carbon-Bismaleimide Composites

Science.gov (United States)

Rider, Andrew N.; Baker, Alan A.; Wang, Chun H.; Smith, Graeme

2011-06-01

Carbon/bismaleimide (BMI) composite is increasingly employed in critical load carrying aircraft structures designed to operate at temperatures approaching 180°C. The high post-cure temperature (above 220°C) required to fully react the BMI resin, however, renders existing on-aircraft prepreg or wet layup repair methods invalid. This paper presents a new on-aircraft repair technique for carbon/BMI composites. The composite prepregs are first warm-staged to improve the ability to evacuate entrapped air. Then the patch is cured in the scarf cavity using the vacuum bag technique, followed by off-aircraft post-cure. The fully cured patch then can be bonded using a structural adhesive.

Trust: the sublime duty in health care leadership.

Science.gov (United States)

Piper, Llewellyn E

2010-01-01

Trust is the essence of human social existence. From the moment of birth, trust is the basic component in any human relationship and interaction. Trust is the Holy Grail for human confidence in others. From human survival to organizational survival, trust is the primordial bond. No organization is more dependent on trust than health care. This article views trust as the most basic fundamental quality for leadership. Trust is a sublime duty of a leader and the leadership of an organization. Leadership sets the culture of trust. Trust is the one quality that is essential for guiding an organization toward serving others. This article addresses trust from many perspectives. Trust is viewed from our subordinates, our peers, our superiors, and the public we serve. This article postulates how trust in an organization is the sublime duty of leadership that unites all human understanding and without it destroys all human relationships.

Source preparation in alpha spectrometry

Energy Technology Data Exchange (ETDEWEB)

Lally, A E [UKAEA Atomic Energy Research Establishment, Harwell. Environmental and Medical Sciences Div.; Glover, K M [UKAEA Atomic Energy Research Establishment, Harwell. Chemistry Div.

1984-06-15

Techniques, for the preparation of sources suitable for alpha spectrometric measurements are presented. These include vacuum sublimation, electrodeposition, self-deposition, direct evaporation, direct precipitation and the use of solvents and spreading agents. The relative merits of each technique and the applicability to both high and low levels of activity are considered.

The Religious-Sublime in Music, Literature and Architecture

DEFF Research Database (Denmark)

Cifuentes-Aldunate, Claudio

2018-01-01

The present article is an attempt to propose the semiotic aspect that produces the ”religious- sublime”. Most of the semiotic characteristics that we use to represent (and produce) the signifiers of the religious-sublime, nevertheless, share their mechanisms with other modalities of ”sublimeness”...

A Practical Cryogen-Free CO2 Purification and Freezing Technique for Stable Isotope Analysis.

Science.gov (United States)

Sakai, Saburo; Matsuda, Shinichi

2017-04-18

Since isotopic analysis by mass spectrometry began in the early 1900s, sample gas for light-element isotopic measurements has been purified by the use of cryogens and vacuum-line systems. However, this conventional purification technique can achieve only certain temperatures that depend on the cryogens and can be sustained only as long as there is a continuous cryogen supply. Here, we demonstrate a practical cryogen-free CO 2 purification technique using an electrical operated cryocooler for stable isotope analysis. This approach is based on portable free-piston Stirling cooling technology and controls the temperature to an accuracy of 0.1 °C in a range from room temperature to -196 °C (liquid-nitrogen temperature). The lowest temperature can be achieved in as little as 10 min. We successfully purified CO 2 gas generated by carbonates and phosphoric acid reaction and found its sublimation point to be -155.6 °C at 0.1 Torr in the vacuum line. This means that the temperature required for CO 2 trapping is much higher than the liquid-nitrogen temperature. Our portable cooling system offers the ability to be free from the inconvenience of cryogen use for stable isotope analysis. It also offers a new cooling method applicable to a number of fields that use gas measurements.

Some attributes of snow occurrence and snowmelt/sublimation rates ...

African Journals Online (AJOL)

Some attributes of snow occurrence and snowmelt/sublimation rates in the Lesotho ... and trimmed MODIS SNOMAP image using the ArcGIS Spatial Analyst tool. ... and hydrology, earth surface processes, and rural livelihoods in the Lesotho ...

A review of the use of Al-alloy vacuum components for operation at 10-13 Torr

Science.gov (United States)

Ishimaru, Hajime

1990-02-01

An extremely high vacuum (XHV) chamber was fabricated and tested. The vacuum chamber was made of special surface finished (EX-process) aluminum alloy in oxygen and argon atmosphere. The chamber was assembled using TIG welding in an argon atmosphere and by electron beam welding. The system was evacuated with a turbo-backed 300 l/s turbomolecular pump separated from the main chamber using a right angle valve. The liquid nitrogen shroud is installed inside the main vacuum chamber. The XHV is maintained by two 300 l/s sputter ion pumps and a titanium sublimation pump with a liquid nitrogen shroud. These pumps are also made of aluminum alloys. An ultimate pressure of 3×10-13 Torr was measured with a point collector gauge with a spherical anode mounted on an Al-flange. Residual gas analysis in the order 10-13 Torr was performed by a newly developed Q-mass filter. To suppress outgassing from the quadrupole electrode, the ion source is mounted on an Al-flange separated from the quadrupole electrode.

A analítica kantiana do sublime em Friedrich Schiller

Directory of Open Access Journals (Sweden)

Artur Bispo dos Santos Neto

2016-10-01

Full Text Available O nosso texto tem como propósito apontar a articulação existente entre a estética kantiana, expressa na sua obra basilar Crítica da faculdade do juízo, e a reflexão estética constituída por Friedrich Schiller mediante a sua noção de sublime. Embora Schiller se inscreva sob o signo da influência da terceira Crítica, vamos mostrar na tessitura deste texto como consegue libertar-se da influência kantiana, ao recusar a centralidade do juízo de gosto na definição do belo e afirmar a beleza (puchritudo como liberdade no fenômeno. Schiller não se limita à investigação do sublime no âmbito da beleza livre (natureza, mas investiga-a especialmente no campo da beleza aderente. Embora o próprio Kant tenha atribuído ao gosto o significado de uma transição do prazer dos sentidos à disposição moral, será Schiller quem radicalizará o propósito de uma educação moral do homem pela mediação do sublime e do patético na arte.

Art, Terrorism and the Negative Sublime

Directory of Open Access Journals (Sweden)

Arnold Berleant

2009-01-01

Full Text Available The range of the aesthetic has expanded to cover not only a wider range of objects and situations of daily life but also to encompass the negative. This includes terrorism, whose aesthetic impact is central to its use as a political tactic. The complex of positive and negative aesthetic values in terrorism are explored, introducing the concept of the sublime as a negative category to illuminate the analysis and the distinctive aesthetic of terrorism.

Indian Vacuum Society: The Indian Vacuum Society

Science.gov (United States)

Saha, T. K.

2008-03-01

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

Gaseous phase heat capacity of benzoic acid

NARCIS (Netherlands)

Santos, L.M.N.B.F.; Alves da Rocha, M.A.; Gomes, L.R.; Schröder, B.; Coutinho, J.A.P.

2010-01-01

The gaseous phase heat capacity of benzoic acid (BA) was proven using the experimental technique called the "in vacuum sublimation/vaporization Calvet microcalorimetry drop method". To overcome known experimental shortfalls, the gaseous phase heat capacity of BA monomer was estimated by ab initio

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

International Nuclear Information System (INIS)

Li, Nannan; Pang, Shucai; Yan, Fei; Chen, Lei; Jin, Dazhi; Xiang, Wei; Zhang, De; Zeng, Baoqing

2015-01-01

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 a new and feasible idea for fabricating nanostructure arrays for vacuum micro-nano-electronic devices, which would spawn the development of vacuum micro-nano-electronics

Synthesis of gallium nitride and related oxides via ammonobasic reactive sublimation (ARS)

Energy Technology Data Exchange (ETDEWEB)

Hernández-Hernández, Luis Alberto; Aguilar-Hernández, Jorge R.; Mejía-García, Concepción; Cruz-Gandarilla, Francisco; Contreras-Puente, Gerardo [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ciudad de México (Mexico); Moure-Flores, Francisco de [Facultad de Química, Materiales-Energía, Universidad Autónoma de Querétaro (Mexico); Melo-Pereira, Osvaldo de, E-mail: schwarzerengelxv@hotmail.com [Facultad de Física, Universidad de La Habana, La Habana (Cuba)

2017-11-15

Ammonobasic reactive sublimation (ARS) is proposed as a novel method to synthesize GaN and related oxides. Results indicate that GaN growth occurs by a nitriding process of Ga and related oxides, establishing a direct dependence on NH{sub 4} OH amount added as a primary chemical reactive. The samples were grown on p-type Si (111) substrates inside a tube furnace, employing GaN powder and NH{sub 4} OH. The characterizations of the samples were carried out by XRD, SEM, EDS and PL techniques, revealing the influence of NH{sub 4} OH on the improvement of GaN synthesis and the enhancement of its optical and structural properties. (author)

Bolted Ribs Analysis for the ITER Vacuum Vessel using Finite Element Submodelling Techniques

Energy Technology Data Exchange (ETDEWEB)

Zarzalejos, José María, E-mail: jose.zarzalejos@ext.f4e.europa.eu [External at F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Fernández, Elena; Caixas, Joan; Bayón, Angel [F4E, c/Josep Pla, n.2, Torres Diagonal Litoral, Edificio B3, E-08019, Barcelona (Spain); Polo, Joaquín [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Guirao, Julio [Numerical Analysis Technologies, S L., Marqués de San Esteban 52, Entlo, 33209 Gijon (Spain); García Cid, Javier [Iberdrola Ingeniería y Construcción, Avenida de Manoteras 20, 28050 Madrid (Spain); Rodríguez, Eduardo [Mechanical Engineering Department EPSIG, University of Oviedo, Gijon (Spain)

2014-10-15

Highlights: • The ITER Vacuum Vessel Bolted Ribs assemblies are modelled using Finite Elements. • Finite Element submodelling techniques are used. • Stress results are obtained for all the assemblies and a post-processing is performed. • All the elements of the assemblies are compliant with the regulatory provisions. • Submodelling is a time-efficient solution to verify the structural integrity of this type of structures. - Abstract: The ITER Vacuum Vessel (VV) primary function is to enclose the plasmas produced by the ITER Tokamak. Since it acts as the first radiological barrier of the plasma, it is classified as a class 2 welded box structure, according to RCC-MR 2007. The VV is made of an inner and an outer D-shape, 60 mm-thick double shell connected through thick massive bars (housings) and toroidal and poloidal structural stiffening ribs. In order to provide neutronic shielding to the ex-vessel components, the space between shells is filled with borated steel plates, called In-Wall Shielding (IWS) blocks, and water. In general, these blocks are connected to the IWS ribs which are connected to adjacent housings. The development of a Finite Element model of the ITER VV including all its components in detail is unaffordable from the computational point of view due to the large number of degrees of freedom it would require. This limitation can be overcome by using submodelling techniques to simulate the behaviour of the bolted ribs assemblies. Submodelling is a Finite Element technique which allows getting more accurate results in a given region of a coarse model by generating an independent, finer model of the region under study. In this paper, the methodology and several simulations of the VV bolted ribs assemblies using submodelling techniques are presented. A stress assessment has been performed for the elements involved in the assembly considering possible types of failure and including stress classification and categorization techniques to analyse

Past, present, and future of sublimation transfer imaging

Science.gov (United States)

Akada, Masanori

1990-07-01

SONY's announcement of tlavica system shaked the world in 1981. In the new nonphotographic imaging system, image is acquired with CCD to be converted into electric image-signal, stored in magnetic recording media,displayed on a CR1 and printed on a special sheet. To get a hard copy, Sublimation Transfer technology was developed. That announcement brought about world-wide R&D of competitive color imaging systems: Ink-jet, Wax transfer,. Sublimation Transfer(ST) and Electrophotography. In spite of much effort,most of those were insufficient for getting a good hard copy. Developing sufficient ST recording media, Dai Nippon Printing started ST recording media business in 1986. It was the first manufacturing scale production and sale of ST recording media in the world. Nowadays ST technology is known for its advantages: high image quality, consistency from copy to copy, smooth tone-reproduction from high-light to maximum density, and easiness to use. In the following paper progress of ST recording media and the present situation and future markets of the media will be presented.

Determination of vapor pressures, enthalpies of sublimation, and enthalpies of fusion of benzenetriols

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Schick, Christoph

2004-01-01

Molar enthalpies of sublimation of 1,2,4-, 1,2,3-, and 1,3,5-tri-hydroxy-benzene, were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. The molar enthalpies of fusion and molar heat capacities of these compounds were measured by DSC. The measured data sets of vaporization, sublimation and fusion enthalpies were checked for internal consistency. Strength of the inter- and intra-molecular hydrogen bonding in di- and tri-hydroxy-benzenes have been assessed

Shades of Grey: The Role of the Sublime in the Memorial to the Murdered Jews of Europe

Directory of Open Access Journals (Sweden)

Karen Wilson Baptist

2012-12-01

Full Text Available As a ‘post-disaster’ landscape, the Memorial to the Murdered Jews of Europe does, arguably, occupy ground where the mass extermination of the Jewish people of Europe was masterminded, but it is not physically a site of death. Commonly, memorial landscapes are erected upon the location where violence, tragedy and disaster have occurred. Divorced from the diasporic dead it seeks to honour, the memorial employs spatial form, the surrounding atmosphere and human memory to potentialise a sublime experience for visitors. The sublime plays an essential role in memorial landscapes because sublime experiences are heightened, unforgettable and enduring. This reduces the possibility that visitors will depart the memorial unscathed, leaving the monument to bear the burden of memory. While a sublime experience can be optimised, it cannot be given, thus, the onus of remembering the Holocaust remains our responsibility.

Vacuum considerations: summary

International Nuclear Information System (INIS)

Blechschmidt, D.; Halama, H.J.

1978-01-01

A summary is given of the efforts of a vacuum systems study group of the workshop on a Heavy Ion Demonstration Experiment (HIDE) for heavy ion fusion. An inadequate knowledge of cross-sections prevents a more concrete vacuum system design. Experiments leading to trustworthy numbers for charge exchange, stripping and capture cross-sections are badly needed and should start as soon as possible. In linacs, beam loss will be almost directly proportional to the pressure inside the tanks. The tanks should, therefore, be built in such a way that they can be baked-out in situ to improve their vacuum, especially if the cross-sections turn out to be higher than anticipated. Using standard UHV techniques and existing pumps, an even lower pressure can be achieved. The vacuum system design for circular machines will be very difficult, and in some cases, beyond the present state-of-the-art

Leak hunting problems associated with controlled thermonuclear fusion experiments

International Nuclear Information System (INIS)

Batzer, T.H.; Murphy, J.J.

1975-01-01

The LLL 2xIIB experiment is briefly described. The vacuum system uses mercury diffusion pumps and titanium sublimation. The base pressure of the guard vacuum is about 10 -5 torr and about 2 x 10 -7 torr in the high vacuum space using the diffusion pumps only. After titanium sublimation, the high vacuum pressure drops into the 10 -9 torr range. A procedure for leak testing using a special sniffer probe is described

Additive scheme for calculation of solvation enthalpies of heterocyclic aromatic compounds. Sublimation/vaporization enthalpy at 298.15 K

International Nuclear Information System (INIS)

Solomonov, Boris N.; Nagrimanov, Ruslan N.; Mukhametzyanov, Timur A.

2016-01-01

Highlights: • Additivity scheme for solvation enthalpies estimation of heteroaromatic compounds was proposed. • Method for determination of vaporization/sublimation enthalpies directly at 298.15 K was developed. • Solution enthalpies of 25 heteroaromatic compounds were measured. • Vaporization/sublimation enthalpies of 44 heteroaromatic compounds were determined. • Obtained values are in good agreement with the results of conventional methods. - Abstract: Hereby we propose a method for determination of vaporization and sublimation enthalpies of heterocyclic and carbonyl-containing aromatic compounds at 298.15 K. According to this method vaporization and sublimation enthalpies at 298.15 K are determined based on enthalpies of solvation and solution. Solvation enthalpies of heteroatomatic and carbonyl-containing compounds are calculated using an additive scheme from the solvation enthalpy of closest aromatic hydrocarbon and contributions related to the exchange of CH-groups of hydrocarbon with corresponding substituent atoms or groups. Measured solution enthalpies together with calculated solvation enthalpies allowed to calculate corresponding vaporization and sublimation enthalpies at 298.15 K for a large number of heterocyclic and carbonyl-containing compounds. We have also found that in a number of cases instead of solution enthalpy in benzene at 298.15 K fusion enthalpy at the melting temperature can be used. Comparison between literature data and calculated vaporization and sublimation enthalpies demonstrates satisfactory performance of the proposed method.

Additive scheme for calculation of solvation enthalpies of heterocyclic aromatic compounds. Sublimation/vaporization enthalpy at 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Solomonov, Boris N., E-mail: boris.solomonov@kpfu.ru; Nagrimanov, Ruslan N.; Mukhametzyanov, Timur A.

2016-06-10

Highlights: • Additivity scheme for solvation enthalpies estimation of heteroaromatic compounds was proposed. • Method for determination of vaporization/sublimation enthalpies directly at 298.15 K was developed. • Solution enthalpies of 25 heteroaromatic compounds were measured. • Vaporization/sublimation enthalpies of 44 heteroaromatic compounds were determined. • Obtained values are in good agreement with the results of conventional methods. - Abstract: Hereby we propose a method for determination of vaporization and sublimation enthalpies of heterocyclic and carbonyl-containing aromatic compounds at 298.15 K. According to this method vaporization and sublimation enthalpies at 298.15 K are determined based on enthalpies of solvation and solution. Solvation enthalpies of heteroatomatic and carbonyl-containing compounds are calculated using an additive scheme from the solvation enthalpy of closest aromatic hydrocarbon and contributions related to the exchange of CH-groups of hydrocarbon with corresponding substituent atoms or groups. Measured solution enthalpies together with calculated solvation enthalpies allowed to calculate corresponding vaporization and sublimation enthalpies at 298.15 K for a large number of heterocyclic and carbonyl-containing compounds. We have also found that in a number of cases instead of solution enthalpy in benzene at 298.15 K fusion enthalpy at the melting temperature can be used. Comparison between literature data and calculated vaporization and sublimation enthalpies demonstrates satisfactory performance of the proposed method.

Potential Identification of Sublimation-Driven Downslope Mass Movement on Mercury

Science.gov (United States)

Malliband, C. C.; Conway, S. J.; Rothery, D. A.; Balme, M. R.

2018-05-01

We have identified a further example of mass movement, in addition to the previously identified example in the pyroclastic vent NE of Rachmaninoff. Both examples show evidence of hollow sublimation being a cause of the mass movements.

Concurrent freezing and sublimation of a liquid-saturated porous slab

International Nuclear Information System (INIS)

Vaidyanathan, N.; Shamsundar, N.

1991-01-01

In this paper analytical models are formulated for describing heat and mass transport during concurrent freezing and sublimation of a one-dimensional liquid-saturated porous slab. The models are based on transient heat transfer in the frozen and wet regions, and quasi-steady heat and mass transfer in the dried region. The enthalpy method in conjunction with a fully implicit finite-difference scheme is employed to obtain the solution in the frozen and wet regions. A quasi-steady solution is used in the dried region. The governing equations are nondimensionalized and parametric studies are performed. The results indicate that the Luikov number, the ambient vapor pressure, and the heat transfer Biot number are important parameters. The results also confirm that the sublimation interface temperature may show significant variations, in contrast to earlier studies in which it was assumed constant

Design consideration on the synchrotron ultrahigh vacuum system

International Nuclear Information System (INIS)

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

1982-01-01

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

Detecting leaks in vacuum bags

Science.gov (United States)

Carlstrom, E. E.

1980-01-01

Small leaks in vacuum bag can be readily detected by eye, using simple chemical reaction: combination of ammonia and acetic acid vapors to produce cloudy white smoke. Technique has been successfully used to test seam integrity and to identify minute pinholes in vacuum bag used in assembly of ceramic-tile heat shield for Space Shuttle Orbiter.

Vacuum Technology for Ion Sources

International Nuclear Information System (INIS)

Chiggiato, P

2013-01-01

The basic notions of vacuum technology for ion sources are presented, with emphasis on pressure profile calculation and choice of pumping technique. A Monte Carlo code (Molflow+) for the evaluation of conductances and the vacuum-electrical analogy for the calculation of time-dependent pressure variations are introduced. The specific case of the Linac4 H - source is reviewed. (author)

GROTESQUE ENCOUNTERS: READING SHAKESPEARE’S THE MERCHANT OF VENICE ALONG THE PRINCIPLES OF THE SUBLIME, BEAUTIFUL AND GROTESQUE

Directory of Open Access Journals (Sweden)

Kathrin Bartha

2015-12-01

Full Text Available This article is an attempt to apply the basic principles of the aesthetic discourse on the sublime, beautiful and grotesque to William Shakespeare's The Merchant of Venice. Even though it is a discourse that only begins in the course of the eighteenth century, I will argue that the structure of the play parallels the model of the traditional sublime, as it deals with a subject-object binary and meditates on the relationship between the material (body and the transcendental (mind. However, the play is also rich in disruptive — or grotesque — forces that unsettle this binary structure. The parallels between the play and the aesthetic discourse could not only help our understanding of postmodern criticism and rewriting of the sublime, but the sublime can also, in turn, shed light on the reception of the play.

System for NO reduction using sublimation of cyanuric acid

Science.gov (United States)

Perry, R.A.

1989-01-24

An arrangement for reducing the NO content of a gas stream comprises contacting the gas stream with HNCO at a temperature effective for heat induced decomposition of HNCO and for resultant lowering of the NO content of the gas stream. Preferably, the HNCO is generated by sublimation of cyanuric acid. 1 fig.

Characterization of the Sublimation and Vapor Pressure of 2-(2-Nitrovinyl) Furan (G-0) Using Thermogravimetric Analysis: Effects of Complexation with Cyclodextrins.

Science.gov (United States)

Ruz, Vivian; González, Mirtha Mayra; Winant, Danny; Rodríguez, Zenaida; Van den Mooter, Guy

2015-08-19

In the present work, the sublimation of crystalline solid 2-(2-nitrovinyl) furan (G-0) in the temperature range of 35 to 60 °C (below the melting point of the drug) was studied using thermogravimetric analysis (TGA). The sublimated product was characterized using Fourier-transformed-infrared spectroscopy (FT-IR) and thin layer chromatography (TLC). The sublimation rate at each temperature was obtained using the slope of the linear regression model and followed apparent zero-order kinetics. The sublimation enthalpy from 35 to 60 °C was obtained from the Eyring equation. The Gückel method was used to estimate the sublimation rate and vapor pressure at 25 °C. Physical mixtures, kneaded and freeze-dried complexes were prepared with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) and analyzed using isothermal TGA at 50 °C. The complexation contributed to reducing the sublimation process. The best results were achieved using freeze-dried complexes with both cyclodextrins.

[Effects of vacuum sealing drainage technique in acute and chronic suppurative tenosynovitis of hand].

Science.gov (United States)

Wang, H; Xia, F; Xing, D M; Ren, D; Feng, W; Chen, Y; Xiao, Z H; Zhao, Z M

2017-05-01

Objective: To investigate the effects of vacuum sealing drainage technique in acute and chronic suppurative tenosynovitis of hand. Methods: A total of 9 cases acute and chronic suppurative tenosynovitis patients from January 2013 to April 2015 in Puai Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology were retrospectively reviewed. There were 6 males and 3 females, aging from 27 to 65 years, the average age was 55 years. There were 3 cases of index finger, 3 cases of middle finger, 2 cases of ring finger, 1 case include three fingers. The infection causes included stabbing with fishbone in 3 cases, stabbing with animal bone fragments in 3 cases, wound by sawdust in 3 cases, meat grinder injury in 1 case, multiple fingers crush injury postoperative infection of garbage truck in 1 case. Bacterial infection included 2 cases with Staphylococcus aureus, 2 cases with Staphylococcus epidermidis, 1 case with normal Escherichia coli, 1 case with mixed infection of Enterobacter aerogenes, Klebsiella oxytoca and Staphylococcus, 1 case with Bauman Acinetobacter bacillus, 1 case with Proteus mirabilis and 1 case of no growth of pathogenic bacteria culture. After thorough debridement, vacuum sealing drainage was used to observe the characteristics of irrigation fluid, the formation of cavity inflammation, the prognosis of infection and the recovery of finger function. Results: Seven patients with suppurative tenosynovitis were treated for 7 to 14 days, replaced the vacuum sealing drainage dressing once; 1 patient was an illustration of the finger tip defect flap infected patients after 21 days of treatment, replaced the vacuum sealing drainage dressing twice, 1 patient was an illustration of the central refers to trauma, postoperative infection patients 28 d, replaced three times in the VSD. The follow-up time was 3 to 12 months (mean 8.2 months), 7 patients without tendon necrosis, secondary suture with no infection, 2 cases of

HISTRAP [Heavy Ion Storage Ring for Atomic Physics] vacuum test stand for pressures of 10-12 Torr

International Nuclear Information System (INIS)

Johnson, J.W.; Atkins, W.H.; Dowling, D.T.; McConnell, J.W.; Milner, W.T.; Olsen, D.K.

1988-01-01

HISTRAP, Heavy Ion Storage Ring for Atomic Physics, is a proposed synchrotron/cooler/storage ring accelerator optimized for advanced atomic physics research. The ring has a circumference of 46.8 m, a bore diameter of about 15 cm, and requires a vacuum of 10 -12 Torr in order to decelerate highly-charged very-heavy ions down to low energies. To be able to test components and procedures to achieve this pressure, a test stand approximately modeling one-sixteenth of the ring vacuum chamber has been built. The 3.5-m-long test stand has been fabricated from 10-cm-diameter components, with 316LN stainless steel flanges. Prior to assembly, these components were vacuum fired at 950/degree/C at a pressure of 10 -4 Torr. The test stand is bakeable in situ at 300/degree/C. Pumping is achieved with two 750-L/s titanium sublimator pumps and one 60-L/s ion pump. Pressure is measured with two extractor ion gauges and a 10 -14 PP RGA. The roughing for the test stand consists of cryosorption pumps followed by a cryopump. A pressure of 4 x 10 -12 Torr has been achieved. 7 refs., 5 figs

Studies of structural material degassing in cryogenic vacuum technique

International Nuclear Information System (INIS)

Koshmarov, Yu.A.; Kupriyanov, V.I.; Ivanov, A.E.; Chubarov, E.V.; Dryamov, V.A.

1976-01-01

The choice and design of cryogenic vacuum pumping equipment require a reliable knowledge of qualitative and quantitative gassing parameters characteristic of the structural materials now in use. The gassing study has been made on the plates of stainless steel, copper and aluminium at a pressure of 1.33 (10 -3 -10 -5 ) Pa (10 -5 -10 -7 mm Hg) at room temperature and degassing duration up to 50 hours. An approximate method is proposed for the determination of the diffusion coefficients initial concentration of dissolved in metals gases, and gaseous exchange coefficient for various components of the gas dissolved in steel copper and aluminium alloys. The data obtained permit the designing of pumping equipment for various vacuum systems

A re-determination and re-assessment of the thermodynamics of sublimation of uranium dioxide

International Nuclear Information System (INIS)

Ackermann, R.J.; Rauh, E.G.; Rand, M.H.

1980-01-01

New mass-spectrometric measurements on the ion-intensity of UO 2 + over urania from 1813 to 2463 K are reported. Although the mean value for the enthalpy of sublimation calculated from these measurements is close to previous values, a detailed examination of the results indicates that there is an appreciable curvature in the log p versus reciprocal-temperature curve for the process: UO 2 (s)→UO 2 (g). This is attributed to a large negative ΔCsub(p) for the sublimation reaction, arising from the sharp increase in Csub(p) (UO 2 (s)) above approximately 1750 K. A thorough re-assessment of the previous studies on the sublimation of urania suggests an 'international' average value of psub(UO 2 )=(1.3+-0.1)x10 -6 atm at 2150 K; Knudsen effusion measurements above 2450 K (p>1x10 -4 atm) are thought to be in error due to departures from molecular flow. Thermal functions for UO 2 (g) have been calculated, assuming a linear molecule and electronic contributions to the partition function based on those of ThO(g). Anharmonicity corrections have been included. When these functions are combined with the thermal functions for UO 2 (s), recently assessed, the third law heat of sublimation at 298.15 K becomes 147.8 kcal.mol -1 with a trend of only 0.2 kcal.mol -1 across the temperature range 1800 to 2400 K. (author)

Microbial analysis of meatballs cooled with vacuum and conventional cooling.

Science.gov (United States)

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.

TORE SUPRA vacuum vessel and shield manufacturing

International Nuclear Information System (INIS)

Blateyron, J.; Lepez, R.

1984-01-01

TORE SUPRA vacuum vessel and vacuum chamber shield manufacturing in progress at Jeumont-Schneider consists of three main phases: - Detail engineering and manufacturing fixture construction; - Prototype section manufacturing and process preparation; - Construction of the 6 production modules. The welding techniques adopted, call for three special automatic processes: TIG, MIG and PLASMA welding which guarantee mechanical strength, vacuum tightness and absence of distortion. Production of the modules began July 1984. (author)

A low feed-through 3D vacuum packaging technique with silicon vias for RF MEMS resonators

Science.gov (United States)

Zhao, Jicong; Yuan, Quan; Kan, Xiao; Yang, Jinling; Yang, Fuhua

2017-01-01

This paper presents a wafer-level three-dimensional (3D) vacuum packaging technique for radio frequency microelectromechanical systems (RF MEMS) resonators. A Sn-rich Au-Sn solder bonding is employed to provide a vacuum encapsulation as well as electrical conductions. Vertical silicon vias are micro-fabricated by glass reflow process. The optimized grounding, via pitch, and all-round shielding effectively reduce feed-through capacitance. Thus the signal-to-background ratios (SBRs) of the transmission signals increase from 17 dB to 20 dB, and the quality factor (Q) values of the packaged resonators go from around 8000 up to more than 9500. The measured average leak rate and shear strength are (2.55  ±  0.9)  ×  10-8 atm-cc s-1 and 42.53  ±  4.19 MPa, respectively. Furthermore, thermal cycling test between  -40 °C and 100 °C and high temperature storage test at 150 °C show that the resonant-frequency drifts are less than  ±7 ppm. In addition, the SBRs and the Q values have no obvious change after the tests. The experimental results demonstrated that the proposed encapsulation technique is well suited for the applications of RF MEMS devices.

Vacuum pumping for controlled thermonuclear reactors

International Nuclear Information System (INIS)

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

1976-01-01

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

Low-level precipitation sublimation on the coasts of East Antarctica

Science.gov (United States)

Grazioli, Jacopo; Genthon, Christophe; Madeleine, Jean-Baptiste; Lemonnier, Florentin; Gallée, Hubert; Krinner, Gerhard; Berne, Alexis

2017-04-01

The weather of East Antarctica is affected by the peculiar morphology of this large continent and by its isolation from the surroundings. The high-elevation interior of the continent, very dry in absolute terms, originates winds that can reach the coastal areas with very high speed and persistence in time. The absence of topographic barriers and the near-ground temperature inversion allow these density-driven air movements to fall from the continent towards the coasts without excessive interaction and mixing with the atmosphere aloft. Thus, the air remains dry in absolute terms, and very dry in relative terms because of the higher temperatures near the coast and the adiabatic warming due to the descent. The coasts of Antarctica are less isolated and more exposed to incoming moist air masses than the rest of the continent, and precipitation in the form of snowfall more frequently occurs. Through its descent, however, snowfall encounters the layer of dry air coming from the continent and the deficit in humidity can lead to the partial or complete sublimation of the precipitating flux. This phenomenon is named here LPS (Low-level Precipitation Sublimation) and it has been observed by means of ground-based remote sensing instruments (weather radars) and atmospheric radio-sounding balloons records in the framework of the APRES3 campaign (Antarctic Precipitation: REmote Sensing from Surface and Space) in the coastal base of Dumont d' Urville (Terre Adélie), and then examined at the continental scale thanks to numerical weather models. LPS occurs over most of the coastal locations, where the total sublimated snowfall can be a significant percentage of the total snowfall. For example, in Dumont d' Urville the total yearly snowfall at 341 m height is less than 80% of the snowfall at 941 m height (the height of maximum yearly accumulation), and at shorter time scales complete sublimation (i.e. virga) often occurs. At the scale of individual precipitation events, LPS is

Glacier mass balance reconstruction by sublimation induced enrichment of chemical species on Cerro Tapado (Chilean Andes

Directory of Open Access Journals (Sweden)

P. Ginot

2006-01-01

Full Text Available A 36 m long ice core down to bedrock from the Cerro Tapado glacier (5536 m a.s.l, 30°08' S, 69°55' W was analyzed to reconstruct past climatic conditions for Northern Chile. Because of the marked seasonality in the precipitation (short wet winter and extended dry summer periods in this region, major snow ablation and related post-depositional processes occur on the glacier surface during summer periods. They include predominantly sublimation and dry deposition. Assuming that, like measured during the field campaign, the enrichment of chloride was always related to sublimation, the chemical record along the ice core may be applied to reconstruct the history of such secondary processes linked to the past climatic conditions over northern Chile. For the time period 1962–1999, a mean annual net accumulation of 316 mm water equivalent (weq and 327 mm weq loss by sublimation was deduced by this method. This corresponds to an initial total annual accumulation of 539 mm weq. The annual variability of the accumulation and sublimation is related with the Southern Oscillation Index (SOI: higher net-accumulation during El-Niño years and more sublimation during La Niña years. The deepest part of the ice record shows a time discontinuity; with an ice body deposited under different climatic conditions: 290 mm higher precipitation but with reduced seasonal distribution (+470 mm in winter and –180 mm in summer and –3°C lower mean annual temperature. Unfortunately, its age is unknown. The comparison with regional proxy data however let us conclude that the glacier buildup did most likely occur after the dry mid-Holocene.

Enthalpies of fusion and enthalpies of solvation of aromatic hydrocarbons derivatives: Estimation of sublimation enthalpies at 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Solomonov, Boris N., E-mail: boris.solomonov@kpfu.ru; Nagrimanov, Ruslan N.; Varfolomeev, Mikhail A.; Buzyurov, Aleksey V.; Mukhametzyanov, Timur A.

2016-03-20

Graphical abstract: - Highlights: • Solution enthalpies of aromatic hydrocarbons derivatives (ArHD) were measured at 298.15 K. • Solution enthalpies of ArHD in benzene at 298.15 K are equal to their fusion enthalpy at melting point. • Sublimation enthalpies of 80 ArHD were calculated as a sum of fusion and solvation enthalpies. • Obtained sublimation enthalpies are in good agreement with the recommended literature data. - Abstract: Enthalpy of sublimation of solid compound can be found using the values of solution enthalpy and solvation enthalpy in any solvent. In this work enthalpies of solution at infinite dilution of a number of aromatic hydrocarbons derivatives in benzene were measured at 298.15 K. Comparison between experimental and literature solution enthalpies in benzene at 298.15 K and fusion enthalpies at melting temperature of aromatic hydrocarbon derivatives showed, that these values are approximately equal. Thereby, fusion enthalpies at melting temperature can be used instead of their solution enthalpies in benzene at 298.15 K for calculation of sublimation enthalpies at 298.15 K. Solvation enthalpies in benzene at 298.15 K required for this procedure were calculated using group additivity scheme. The sublimation enthalpies of 80 aromatic hydrocarbons derivatives at 298.15 K were evaluated as a difference between fusion enthalpies at melting temperature and solvation enthalpies in benzene at 298.15 K. Obtained in this work values of sublimation enthalpy at 298.15 K for studied compounds were in a good agreement with available literature data.

Vacuum ultraviolet photochemistry of polymers

International Nuclear Information System (INIS)

Skurat, Vladimir

2003-01-01

under vacuum conditions. The energetic yield of erosion is intensity-dependent because of the limited rate of sublimation of polymer fragments

Concentration of noble metals by sublimation during the analysis of massive samples

International Nuclear Information System (INIS)

Chuburkov, Yu.T.; Zhujkov, B.L.; Gehrbish, Sh.; Al'pert, L.K.; Chan Zuj Ty

1990-01-01

The possibility of concentrating noble metals from terrestrial samples of various composition by chemical sublimation in an air stream at a temperature of 1000-1200 deg C was examined. It was found that the chemical yields of Au, Pt, Ir, Ru, Os and Re for all the samples increased by introducing solid additives of FeCl 2 , TiO 2 and Nb 2 O 5 . The concentration technique provides the possibility of determining some noble metals in massive samples (up to 50 g) with widely ranging element contents. By using gamma and neutron activation on a microtron, the detection limits of 3x10 -2 ppm for Pt and Ir and 4x10 -3 ppm for Au were achieved. In the case of X-ray fluorescence analysis, the detection limit for these elements was 0.4 ppm

Sublimation of icy planetesimals and the delivery of water to the habitable zone around solar type stars

Science.gov (United States)

Brunini, Adrián; López, María Cristina

2018-06-01

We present a semi analytic model to evaluate the delivery of water to the habitable zone around a solar type star carried by icy planetesimals born beyond the snow line. The model includes sublimation of ice, gas drag and scattering by an outer giant planet located near the snow line. The sublimation model is general and could be applicable to planetary synthesis models or N-Body simulations of the formation of planetary systems. We perform a short series of simulations to asses the potential relevance of sublimation of volatiles in the process of delivery of water to the inner regions of a planetary system during early stages of its formation. We could anticipate that erosion by sublimation would prevent the arrival of much water to the habitable zone of protoplanetary disks in the form of icy planetesimals. Close encounters with a massive planet orbiting near the outer edge of the snow line could make possible for planetesimals to reach the habitable zone somewhat less eroded. However, only large planetesimals could provide appreciable amounts of water. Massive disks and sharp gas surface density profiles favor icy planetesimals to reach inner regions of a protoplanetary disk.

Snowmelt and sublimation: field experiments and modelling in the High Atlas Mountains of Morocco

Directory of Open Access Journals (Sweden)

O. Schulz

2004-01-01

Full Text Available Snow in the High Atlas Mountains is a major source for freshwater renewal and for water availability in the semi-arid lowlands of south-eastern Morocco. Snowfall- and snow-ablation monitoring and modelling is important for estimating potential water delivery from the mountain water towers to the forelands. This study is part of GLOWA-IMPETUS, an integrated management project dealing with scarce water resources in West Africa. The Ameskar study area is located to the south of the High Atlas Mountains, in their rain shadow. As a part of the M’Goun river basin within the upper Drâa valley, the study area is characterised by high radiation inputs, low atmospheric humidity and long periods with sub-zero temperatures. Its altitude ranges between 2000 m and 4000 m, with dominant north- and south-facing slopes. Snowfall occurs mainly from November to April but even summit regions can become repeatedly devoid of snow cover. Snow cover maps for the M’Goun basin (1240 km2 are derived from calculations of NDSI (Normalized Difference Snow Index from MODIS satellite images and snow depth is monitored at four automatic weather stations between 2000–4000 m. Snowfall events are infrequent at lower altitudes. The presence of snow penitentes at altitudes above 3000 m indicates that snow sublimation is an important component of snow ablation. Snow ablation was modelled with the UEB Utah Energy Balance Model (Tarboton and Luce, 1996. This single layer, physically-based, point energy and mass balance model is driven by meteorological variables recorded at the automatic weather stations at Tounza (2960 m and Tichki (3260 m. Data from snow pillows at Tounza and Tichki are used to validate the model’s physical performance in terms of energy and water balances for a sequence of two snowfall events in the winter of 2003/4. First UEB modelling results show good overall performance and timing of snowmelt and sublimation compared to field investigations. Up to 44

Sublimation and thermal decomposition of ammonia borane: Competitive processes controlled by pressure

Energy Technology Data Exchange (ETDEWEB)

Kondrat’ev, Yu.V.; Butlak, A.V.; Kazakov, I.V.; Timoshkin, A.Y., E-mail: a.y.timoshkin@spbu.edu

2015-12-20

Highlights: • We measured sublimation enthalpy of ammonia borane at 357 K by drop-calorimetry. • We determined activation energy for ammonia borane decomposition by tensimetry. • At 357 K decomposition and sublimation are competitive and depend on the pressure. • We propose new values for the Δ{sub f}H° of solid ammonia borane and polyamidoborane. - Abstract: Thermal behavior of ammonia borane BH{sub 3}NH{sub 3} (AB) has been studied by calorimetry, tensimetry and mass spectrometry methods. It is shown, that depending on vapor pressure in the system two competitive processes are taking place at 357 K. At atmospheric pressure thermal decomposition with hydrogen evolution is the dominant process: BH{sub 3}NH{sub 3(s)} = 1/n (BH{sub 2}NH{sub 2}){sub n(s)} + H{sub 2(g)} (1). At low pressures (circa 4 mTorr) the major process is endothermic sublimation of AB: BH{sub 3}NH{sub 3(s)} = BH{sub 3}NH{sub 3(g)} (2). At intermediate pressures both processes occur simultaneously. Enthalpies for the processes (1) and (2) have been determined by drop-calorimetry method: Δ{sub (1)}H{sub 357}° = −24.8 ± 2.3 kJ mol{sup −1} and Δ{sub sub}H{sub 357}°(BH{sub 3}NH{sub 3}) = 76.3 ± 3.0 kJ mol{sup −1}. Solid products after sublimation and decomposition have been characterized by IR and NMR spectroscopy; gaseous forms were studied by mass spectrometry. Activation energy of 94 ± 11 kJ mol{sup −1} for the process (1) in range 327–351 K was determined by static tensimetry method. Based on the analysis of available thermodynamic characteristics, new values for the standard formation enthalpy of solid AB −133.4 ± 5.2 kJ mol{sup −1} and polyamidoborane −156.7 ± 5.8 kJ mol{sup −1} are recommended.

Vacuum and ultravacuum physics and technology

CERN Document Server

Bello, Igor

2018-01-01

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

Modified solution calorimetry approach for determination of vaporization and sublimation enthalpies of branched-chain aliphatic and alkyl aromatic compounds at T = 298.15 K

International Nuclear Information System (INIS)

Varfolomeev, Mikhail A.; Novikov, Vladimir B.; Nagrimanov, Ruslan N.; Solomonov, Boris N.

2015-01-01

Highlights: • Solution enthalpies of 18 branching-chain alkyl aromatic and aliphatic compounds in cyclohexane were measured. • Group contributions to the enthalpy of solvation due to branching and substitution in carbon chain were evaluated. • Modified solution calorimetry based approach for determination of vaporization/sublimation enthalpies was proposed. • This approach provides vaporization/sublimation enthalpies directly at T = 298.15 K. • Vaporization/sublimation enthalpies of 35 branched-chain alkyl aromatic and aliphatic compounds were determined. - Abstract: The enthalpies of solution, solvation and vaporization/sublimation are interrelated values combined in the simplest thermodynamic circle. Hence, experimental determination of vaporization/sublimation enthalpy can be substituted by experimentally simpler determination of solution enthalpy when solvation enthalpy is known. Previously it was found that solvation enthalpies of a wide range of unbranched aliphatic and aromatic solutes in saturated hydrocarbons are in good linear correlation with their molar refraction values. This allows to estimate the vaporization/sublimation enthalpy of any unbranched organic compound from its solution enthalpy in saturated hydrocarbon and molar refraction. In the present work this approach was modified for determination of vaporization/sublimation enthalpy of branched-chain alkyl aromatic and aliphatic compounds. Group contributions to the enthalpy of solvation due to the branching of carbon chain were evaluated. Enthalpies of solution at infinite dilution of 18 branched-chain aliphatic and alkyl aromatic compounds were measured at T = 298.15 K. Vaporization/sublimation enthalpies for 35 branched aliphatic and alkyl aromatic compounds were determined by using modified solution calorimetry approach. These values are in good agreement with available literature data on vaporization/sublimation enthalpies obtained by conventional methods.

Handbook of vacuum physics

CERN Document Server

1964-01-01

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

Simulation of wind-induced snow transport and sublimation in alpine terrain using a fully coupled snowpack/atmosphere model

Science.gov (United States)

Vionnet, V.; Martin, E.; Masson, V.; Guyomarc'h, G.; Naaim-Bouvet, F.; Prokop, A.; Durand, Y.; Lac, C.

2014-03-01

In alpine regions, wind-induced snow transport strongly influences the spatio-temporal evolution of the snow cover throughout the winter season. To gain understanding on the complex processes that drive the redistribution of snow, a new numerical model is developed. It directly couples the detailed snowpack model Crocus with the atmospheric model Meso-NH. Meso-NH/Crocus simulates snow transport in saltation and in turbulent suspension and includes the sublimation of suspended snow particles. The coupled model is evaluated against data collected around the experimental site of Col du Lac Blanc (2720 m a.s.l., French Alps). First, 1-D simulations show that a detailed representation of the first metres of the atmosphere is required to reproduce strong gradients of blowing snow concentration and compute mass exchange between the snowpack and the atmosphere. Secondly, 3-D simulations of a blowing snow event without concurrent snowfall have been carried out. Results show that the model captures the main structures of atmospheric flow in alpine terrain. However, at 50 m grid spacing, the model reproduces only the patterns of snow erosion and deposition at the ridge scale and misses smaller scale patterns observed by terrestrial laser scanning. When activated, the sublimation of suspended snow particles causes a reduction of deposited snow mass of 5.3% over the calculation domain. Total sublimation (surface + blowing snow) is three times higher than surface sublimation in a simulation neglecting blowing snow sublimation.

Application of a Kalman filter to UF6 gaseous diffusion plant freezer/sublimer systems

International Nuclear Information System (INIS)

Ruppel, F.R.

1992-03-01

A signal is required to control the flow of UF 6 in gaseous diffusion plant freezer/sublimer systems. The original strategy envisioned for deriving a flow signal was to take the derivative of the freezer/sublimer weigh cell signal. However, the derivative of the digitized weight signal is noisy, preventing good control. In addition, a bias is introduced into the weight derivative signal because a refrigerant is circulated through a shell-and-tube heat exchanger inside the freezer/sublimer. The weight of the refrigerant is included in the weight measured by the weigh cell. If the circulation rate of the refrigerent is not steady state, a bias exists. Measurements of upstream pressure, vessel pressure, and output to the system control valve are available to the control system. Thus, if the flow through the control valve is characterized properly by the measurements, a Kalman filter can be used in conjunction with these auxiliary inputs and the weigh cell input to overcome the noise and bias problem and provide an improve estimate of flow rate. A discussion of the development and the current status of a Kalman filter used for this application is given. 5 refs

Is the Free Vacuum Energy Infinite?

International Nuclear Information System (INIS)

Shirazi, S. M.; Razmi, H.

2015-01-01

Considering the fundamental cutoff applied by the uncertainty relations’ limit on virtual particles’ frequency in the quantum vacuum, it is shown that the vacuum energy density is proportional to the inverse of the fourth power of the dimensional distance of the space under consideration and thus the corresponding vacuum energy automatically regularized to zero value for an infinitely large free space. This can be used in regularizing a number of unwanted infinities that happen in the Casimir effect, the cosmological constant problem, and so on without using already known mathematical (not so reasonable) techniques and tricks

Schiller Goes to the Movies: Locating the Sublime in "Thelma and Louise."

Science.gov (United States)

Hoyng, Peter

1997-01-01

Endeavors to make students aware of similarities between today's movie culture and the theater of the 18th century; parallels between a traditional drama and a movie script; and Schiller's understanding of the sublime. (36 references) (Author/CK)

Pumping behavior of sputter ion pumps

International Nuclear Information System (INIS)

Chou, T.S.; McCafferty, D.

The ultrahigh vacuum requirements of ISABELLE is obtained by distributed pumping stations. Each pumping station consists of 1000 l/s titanium sublimation pump for active gases (N 2 , H 2 , O 2 , CO, etc.), and a 20 l/s sputter ion pump for inert gases (methane, noble gases like He, etc.). The combination of the alarming production rate of methane from titanium sublimation pumps (TSP) and the decreasing pumping speed of sputter ion pumps (SIP) in the ultrahigh vacuum region (UHV) leads us to investigate this problem. In this paper, we first describe the essential physics and chemistry of the SIP in a very clean condition, followed by a discussion of our measuring techniques. Finally measured methane, argon and helium pumping speeds are presented for three different ion pumps in the range of 10 -6 to 10 -11 Torr. The virtues of the best pump are also discussed

Comparative study of titanium carbide and nitride coatings grown by cathodic vacuum arc technique

International Nuclear Information System (INIS)

Devia, D.M.; Restrepo-Parra, E.; Arango, P.J.

2011-01-01

Titanium nitride (TiN), titanium carbide (TiC) thin films and TiC/TiN bilayers have been deposited on AISI 304 stainless steel substrates by plasma assisted physical vapor deposition technique - reactive pulsed vacuum arc method. The coatings were characterized in terms of crystalline structure, microstructure and chemical nature by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. Tribological behavior was investigated using ball on disc technique. The average coefficient of friction was measured, showing lower values for the TiN/TiC bilayer. Dynamic wear curves were performed for each coating, observing a better wear resistance for TiN/TiC bilayers, compared to TiN and TiC monolayers. On the other hand, the TiCN formation in the TiN/TiC bilayer was observed, being attributed to the interdiffusion between TiN and TiC at the interface. Moreover, the substrate temperature influence was analysing observing a good behavior at T S = 115 °C.

Measurement of the enthalpies of vaporization and sublimation of solids aromatic hydrocarbons by differential scanning calorimetry

International Nuclear Information System (INIS)

Rojas, Aaron; Orozco, Eulogio

2003-01-01

An experimental procedure is proposed for direct measurement of the heat involved in the vaporization of a solid organic compound above its normal melting temperature. This technique consists on the fusion of a solid aromatic hydrocarbon, which is then vaporized by a sudden decrease of the pressure. The direct register of heat flow as function of time by differential scanning calorimetry allows the quantifying of the enthalpy of vaporization of compounds such as phenanthrene, β-naphthol, pyrene, and anthracene. Enthalpies of vaporization were measured in an isothermal mode over a range of temperatures from 10 to 20 K above the melting temperatures of each compound, while enthalpies of fusion were determined from separate experiments performed in a scanning mode. Enthalpies of sublimation are computed from results of fusion and vaporization, and then compared with results from the literature, which currently are obtained by calorimetric or indirect techniques

Thermodynamic study of sublimation, melting and vaporization of scandium(III) dipivaloylmethanate derivatives

International Nuclear Information System (INIS)

Zherikova, Kseniya V.; Zelenina, Ludmila N.; Chusova, Tamara P.; Gelfond, Nikolay V.; Morozova, Natalia B.

2016-01-01

Highlights: • Thermal properties of two volatile fluorinated Sc(III) beta-diketonates were studied. • Saturated and unsaturated vapor pressures were measured. • DSC analysis was carried out. • Sublimation, evaporation and melting enthalpies and entropies were derived. • Effect of fluorine introduction on volatility and thermal stability was established. - Abstract: The present work deals with the investigation of thermal properties of two volatile scandium(III) beta-diketonates with 2,2,6,6-tetramethyl-4-fluoro-3,5-heptanedione and 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione which have been synthesized and purified. Using the static method with glass membrane gauge-manometer the temperature dependencies of saturated and unsaturated vapor pressure were measured for the first time. The temperatures and enthalpies of melting were measured for these compounds by differential scanning calorimetry. The standard thermodynamic characteristics of enthalpy and entropy for sublimation, vaporization and melting processes were derived.

Key composition optimization of meat processed protein source by vacuum freeze-drying technology

Directory of Open Access Journals (Sweden)

Yan Ma

2018-05-01

Full Text Available Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined. Keywords: Ham, Tenderloin, Vacuum freeze-dry, Processing, Optimization

Application of vacuum metallurgy to separate pure metal from mixed metallic particles of crushed waste printed circuit board scraps.

Science.gov (United States)

Zhan, Lu; Xu, Zhenming

2008-10-15

The principle of separating pure metal from mixed metallic particles (MMPs) byvacuum metallurgy is that the vapor pressures of various metals at the same temperature are different As a result, the metal with high vapor pressure and low boiling point can be separated from the mixed metals through distillation or sublimation, and then it can be recycled through condensation under a certain condition. The vacuum metallurgy separation (VMS) of MMPs of crushed waste printed circuit boards (WPCBs) has been studied in this paper. Theoretical analyses show that the MMPs (copper, zinc, bismuth, lead, and indium, for example) can be separated by vacuum metallurgy. The copper particles (0.15-0.20 mm) and zinc particles (<0.30 mm) were chosen to simulate the MMPs of crushed WPCBs. Experimental results show that the separated efficiency of zinc in the copper-rich particles achieves 96.19 wt % when the vacuum pressure is 0.01-0.10 Pa, the heating temperature is 1123 K, and the heating time is 105 min. Under this operation condition, the separated efficiency of zinc in the copper-rich particles from crushed WPCBs achieves 97.00 wt % and the copper purity increases from 90.68 to 99.84 wt %.

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

International Nuclear Information System (INIS)

Armenta, R.

2005-01-01

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

Vacuum characteristics of the RF-cavity for TRISTAN main ring

International Nuclear Information System (INIS)

Mizuno, H.

1987-10-01

Vacuum characteristics of the RF-cavity for TRISTAN main ring were tested. An APS (Alternating Periodic Structure) 18-cell cavity unit was made of low carbon steel S25C, and inner surface was electro-plated with copper of 100 μm in a pyrophosphorous-acid bath. After 24-hours bake-out at 140 deg C by a boiler, the outgassing rate of a test cavity was mainly dominated by the hydrogen permeation from the cooling water channel through the low carbon steel wall into the vacuum. By the use of anti-corrosion agent, the outgassing rate of the test cavity was decreased down to 1 x 10 -13 Torr · l/sec · cm 2 , after the bake-out at 140 deg C for 24 hours. After hydrogen degassing at 140 deg C for 10-days, the APS cavity unit was baked at 140 deg C for 24 hours, the ultimate pressure of the cavity reached down to 6 x 10 -10 Torr, and 2.7 x 10 -10 Torr, pumped by four 300 l/sec ion-pumps and by two 300 l/sec ion-pumps and two Ti-sublimation pumps with liquid nitrogen shroud respectively. The APS cavity unit was conditioned up to 250 kW/9-cell for 36 hours pumped by four 300 l/sec ion pumps, the ultimate pressure of the cavity was 5 x 10 -9 Torr with the RF power of 150 kW/9-cell on. (author)

Orbital Evolution of Dust Particles in the Sublimation Zone near the Sun

Science.gov (United States)

Shestakova, L. I.; Demchenko, B. I.

2018-03-01

We have performed the calculations of the orbital evolution of dust particles from volcanic glass ( p-obsidian), basalt, astrosilicate, olivine, and pyroxene in the sublimation zone near the Sun. The sublimation (evaporation) rate is determined by the temperature of dust particles depending on their radius, material, and distance to the Sun. All practically important parameters that characterize the interaction of spherical dust particles with the radiation are calculated using the Mie theory. The influence of radiation and solar wind pressure, as well as the Poynting-Robertson drag force effects on the dust dynamics, are also taken into account. According to the observations (Shestakova and Demchenko, 2016), the boundary of the dust-free zone is 7.0-7.6 solar radii for standard particles of the zodiacal cloud and 9.1-9.2 solar radii for cometary particles. The closest agreement is obtained for basalt particles and certain kinds of olivine, pyroxene, and volcanic glass.

Reparation effects of vacuum wound therapy in patients with diabetic foot syndrome.

OpenAIRE

Besedin, A. M.

2015-01-01

Vacuum Therapy (Vacuum-assisted closure, VAC) - a method of complex therapy which is used to improve the healing of both acute chronic wounds in patients with diabetic foot syndrome. Due to widespread introduction of this technique, unique cell, extracellular and general effects of its use in the treatment of patients with purulent-necrotic complications of diabetic foot syndrome, a technique of vacuum wound therapy has been successfully used in many surgical departments of Ukraine. Despite t...

Gases and vacua handbook of vacuum physics

CERN Document Server

Beck, A H

2013-01-01

Handbook of Vacuum Physics, Volume 1: Gases and Vacua presents three major topics, which are the fourth to sixth parts of this volume. These topics are the remarks on units of physical quantities; kinetic theory of gases and gaseous flow; and theory of vacuum diffusion pumps. The first topic aims to present concisely the significance of units of physical quantities, catering the need and interest of those who take measurements and make calculations in different fields of vacuum sciences. The technique and applications of this particular topic are also provided. The second main topic focuses sp

Vacuum amplification of the high-frequency electromagnetic radiation

OpenAIRE

Vilkovisky, G. A.

1998-01-01

When an electrically charged source is capable of both emitting the electromagnetic waves and creating charged particles from the vacuum, its radiation gets so much amplified that only the backreaction of the vacuum makes it finite. The released energy and charge are calculated in the high-frequency approximation. The technique of expectation values is advanced and employed.

Construction of vacuum system for Tristan accumulation ring

International Nuclear Information System (INIS)

Ishimaru, H.; Horikoshi, G.; Kobayashi, M.; Kubo, T.; Mizuno, H.; Momose, T.; Narushima, K.; Watanabe, H.; Yamaguchi, H.

1983-01-01

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 and 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

Apollo telescope mount thermal systems unit thermal vacuum test

Science.gov (United States)

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.

Development of a Modified Vacuum Cleaner for Lunar Surface Systems

Science.gov (United States)

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

Experience with the vacuum assisted closure negative pressure technique in the treatment of non-healing diabetic and dysvascular wounds.

Science.gov (United States)

Clare, Michael P; Fitzgibbons, Timothy C; McMullen, Scott T; Stice, R Colleen; Hayes, Dennis F; Henkel, Loree

2002-10-01

The purpose of this study is to report our experience with the Vacuum Assisted Closure (VAC) negative pressure technique in patients with non-healing wounds of the foot, ankle, and lower limb. We retrospectively reviewed 17 patients with non-healing wounds of the lower extremity who underwent treatment using the Vacuum Assisted Closure (VAC) device. Thirteen of 17 (76%) had diabetes mellitus, nine of whom were insulin-dependent, and 10 of whom had associated peripheral neuropathy. Eight of 17 (47%) had severe peripheral vascular disease. All had failed previous management with serial wound debridements and dressing changes; 15 of 17 (88%) had previously completed at least one course of oral antibiotics. Thirteen of 17 (76%) had previously undergone operative irrigation and debridement of the wounds; six of 17 (35%) had previously undergone revascularization procedures of the involved extremity. Five of 17 (29%) had wounds necessitating an amputation procedure prior to the present treatment; seven of 17 (41%) had failed treatment with local growth factors prior to the present treatment. Average length of treatment with the VAC device was 8.2 weeks. Fourteen of 17 (82%) wounds successfully healed; four underwent split-thickness skin grafting for wound closure; four were briefly treated with local growth factors; six were treated with only dressing changes following VAC treatment. Three of 17 (18%) wounds failed VAC treatment; all three patients had diabetes and had wounds located in the midfoot or forefoot; two of three had severe peripheral vascular disease. Our results indicate that the Vacuum Assisted Closure negative pressure technique is emerging as an acceptable option for wound care of the lower extremity. Not all patients are candidates for such treatment; those patients with severe peripheral vascular disease or smaller forefoot wounds may be best treated by other modalities. Larger wounds seem to be better suited for skin grafting or two-stage primary

NMR and Chemometric Characterization of Vacuum Residues and Vacuum Gas Oils from Crude Oils of Different Origin

Directory of Open Access Journals (Sweden)

Jelena Parlov Vuković

2015-03-01

Full Text Available NMR spectroscopy in combination with statistical methods was used to study vacuum residues and vacuum gas oils from 32 crude oils of different origin. Two chemometric metodes were applied. Firstly, principal component analysis on complete spectra was used to perform classification of samples and clear distinction between vacuum residues and vacuum light and heavy gas oils were obtained. To quantitatively predict the composition of asphaltenes, principal component regression models using areas of resonance signals spaned by 11 frequency bins of the 1H NMR spectra were build. The first 5 principal components accounted for more than 94 % of variations in the input data set and coefficient of determination for correlation between measured and predicted values was R2 = 0.7421. Although this value is not significant, it shows the underlying linear dependence in the data. Pseudo two-dimensional DOSY NMR experiments were used to assess the composition and structural properties of asphaltenes in a selected crude oil and its vacuum residue on the basis of their different hydrodynamic behavior and translational diffusion coefficients. DOSY spectra showed the presence of several asphaltene aggregates differing in size and interactions they formed. The obtained results have shown that NMR techniques in combination with chemometrics are very useful to analyze vacuum residues and vacuum gas oils. Furthermore, we expect that our ongoing investigation of asphaltenes from crude oils of different origin will elucidate in more details composition, structure and properties of these complex molecular systems.

Wasting the Future: The Technological Sublime, Communications Technologies, and E-waste

Directory of Open Access Journals (Sweden)

Sebine Label

2012-08-01

Full Text Available Literally speaking, e-waste is the future of communications. E-waste is the fastest growing waste stream in the world, much of it communications technologies from cell phones to laptops, televisions to peripherals. As a result of policies of planned obsolescence working computers, cell phones, and tablets are routinely trashed. One of the most powerful and enduring discourses associated with emerging technologies is the technological sublime, in which technology is seen as intellectually, emotionally, or spiritually transcendent. It comprises a contradictory impulse that elevates technology with an almost religious fervor, while simultaneously overlooking some of the consequences of industrialism, as well as ignoring the necessity of social, economic, and governmental infrastructures necessary to the implementation and development of new technologies. The idea that a new technology will not pollute or harm the environment is a persistent, though often quickly passed over, theme in the technological sublime, echoed in discourses about emerging technologies such as the silicon chip, the internet, and other ICTs. In this paper, I make connections between the discourse of newness, the practice of planned obsolescence, and the mountains of trashed components and devices globally. Considering the global context demonstrates the realities of the penetration of ICTs and their enduring pollution and negative implications for the health of humans and nonhumans, including plants, animals, waterways, soil, air and so on. I use the discourse of the technological sublime to open up and consider the future of communications, to argue that this discourse not only stays with us but also contains within it two important and related components, the promise of ecological harmony and a future orientation. I argue that these lingering elements keep us from considering the real future of communications – e-waste – and that, as communications scholars, we must also

An examination of the thermodynamics of fusion, vaporization, and sublimation of ibuprofen and naproxen by correlation gas chromatography.

Science.gov (United States)

Maxwell, Rachel; Chickos, James

2012-02-01

The vaporization enthalpies of (S)-ibuprofen and (S)-naproxen measured by correlation gas chromatography at T = 298.15 K are reported and compared with literature values. Adjustment of the fusion enthalpies of (RS)- and (S)-ibuprofen and (S)-naproxen to T = 298.15 K and combined with the vaporization enthalpy of the (S)-enantiomer of both ibuprofen and naproxen also at T = 298.15 K resulted in the sublimation enthalpies of both (S)-enantiomers. On the assumption that the vaporization enthalpy of the racemic form of ibuprofen is within the experimental uncertainty of the chiral form, the sublimation enthalpy of racemic ibuprofen was also evaluated. The vaporization and sublimation enthalpies compare favorably to the most of the literature values for the racemic form of ibuprofen but differ from the value reported for chiral ibuprofen. The literature values of (S)-naproxen are somewhat smaller than the values measured in this work. The following vaporization enthalpies were measured for (S)-ibuprofen and (S)-naproxen, respectively: ΔH(vap) (298.15 K), 106.0 ± 5.5, 132.2 ± 5.0 kJ·mol(-1) . Sublimation enthalpies of 122.7 ± 5.6 and 155.2 ± 7.1 kJ·mol(-1) were calculated for the (S)-enantiomers of ibuprofen and naproxen and a value of 128.9 ± 5.8 kJ·mol(-1) was estimated for the racemic form of ibuprofen. Copyright © 2011 Wiley Periodicals, Inc.

Poetiche del sublime. Il Coro di morti dalle Operette morali a Goffredo Petrassi

Directory of Open Access Journals (Sweden)

Giovanni Vito Distefano

2018-01-01

Full Text Available In un autore come Leopardi, incline al serio in misura apparentemente esclusiva e poco votato all’arte drammatica, è tuttavia in un piccolo capolavoro tragicomico che possono individuarsi le prime tracce di una moderna estetica del sublime. L’articolo propone innanzitutto una lettura in chiave metapoetica del Coro di morti, volta ad osservare la salda convergenza che nella scrittura leopardiana lega reciporcamente gli avanzamenti del pensiero – la verità di una condizione umana irresolubilmente e incomprensibilmente priva della felicità – e gli sviluppi attinenti al piano formale e a quello della riflessione filosofico-estetica – con la messa in discussione tanto della classicistica estetica della mimesis, quanto di quella romantica del sentimentale. Infine, nella seconda parte, il paradigma estetico del sublime fornirà i termini entro i quali tracciare una ricostruzione del procedimento adattivo che lega all’originale leopardiano la trasposizione musicale realizzata nel 1941 da Goffredo Petrassi.

Extraction of trapped gases in ice cores for isotope analysis

International Nuclear Information System (INIS)

Leuenberger, M.; Bourg, C.; Francey, R.; Wahlen, M.

2002-01-01

The use of ice cores for paleoclimatic investigations is discussed in terms of their application for dating, temperature indication, spatial time marker synchronization, trace gas fluxes, solar variability indication and changes in the Dole effect. The different existing techniques for the extraction of gases from ice cores are discussed. These techniques, all to be carried out under vacuum, are melt-extraction, dry-extraction methods and the sublimation technique. Advantages and disadvantages of the individual methods are listed. An extensive list of references is provided for further detailed information. (author)

Enthalpies of solution, enthalpies of fusion and enthalpies of solvation of polyaromatic hydrocarbons: Instruments for determination of sublimation enthalpy at 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Solomonov, Boris N., E-mail: boris.solomonov@ksu.ru; Varfolomeev, Mikhail A.; Nagrimanov, Ruslan N.; Mukhametzyanov, Timur A.; Novikov, Vladimir B.

2015-12-20

Graphical abstract: - Highlights: • Solution enthalpies of aromatic hydrocarbons were measured at 298.15 K. • Solution enthalpy of aromatic hydrocarbons in benzene is equal to their fusion enthalpy. • Method for calculation of solvation enthalpy of aromatic hydrocarbons was proposed. • Approach for estimation of aromatic hydrocarbons sublimation enthalpy was developed. • Obtained sublimation enthalpies coincide well with the recommended literature data. - Abstract: In this work a simple method for calculation of solvation enthalpies of polyaromatic hydrocarbons (PAHs) in various solvents at 298.15 K was proposed. According to this method the enthalpy of solvation of any polyaromatic hydrocarbon in a particular solvent can be calculated on the basis of the general formula of the compound, the solvation enthalpy of benzene in the same solvent and parameter related to the contribution of hydrogen atom into solvation enthalpy. The validity of the proposed method was confirmed by the comparison of calculated and experimentally measured values of solvation enthalpies of PAHs in benzene, tetrahydrofuran and acetonitrile. This method was used for determination of the sublimation enthalpy of PAHs at 298.15 K based on the general relationship between the enthalpy of sublimation/vaporization of the compound of interest and its enthalpies of solution and solvation in the same solvent at 298.15 K. Enthalpies of solution at infinite dilution of several PAHs were measured in acetonitrile, benzene and tetrahydrofuran at 298.15 K. It was shown that solution enthalpies of PAHs in benzene at 298.15 K are approximately equal to their fusion enthalpies at the melting temperature. Solvation enthalpies of 15 PAHs at 298.15 K calculated according to the proposed method together with corresponding fusion enthalpy values (at the melting temperature) were used to calculate the sublimation enthalpy values at 298.15 K. Comparison of the obtained results with recommended values of

An examination of the thermodynamics of fusion, vaporization, and sublimation of several parabens by correlation gas chromatography.

Science.gov (United States)

Umnahanant, Patamaporn; Chickos, James

2011-05-01

The vaporization, fusion, and sublimation enthalpies of methyl, ethyl, propyl, and butyl paraben are reported and compared with literature values. The vaporization enthalpies were measured by correlation gas chromatography and the fusion enthalpies by differential scanning calorimetry. Adjusted to T = 298.15 K, these enthalpies were combined to yield the sublimation enthalpy. The results compare favorably to some of the literature values but do not support the reversal in magnitude of both the vaporization and sublimation enthalpy previously reported for propyl and butyl paraben. The following fusion and vaporization enthalpies were measured for methyl through to butyl paraben, respectively: ΔH(fus) (T(fus) ) 26.3 ± 0.1 (398.6 K), 26.5 ± 0.1 (388.5 K), 27.3 ± 0.1 (368.8), and 25.9 ± 0.3 (340.7 K) kJ·mol(-1); ΔH(vap) (298.15 K) 79.5 ± 0.5, 84.0 ± 0.5, 89.7 ± 0.6, and 95.8 ± 0.6 kJ·mol(-1). The results are believed to be accurate to ± 4 kJ·mol(-1). Copyright © 2011 Wiley-Liss, Inc.

Leybold vacuum handbook

CERN Document Server

Diels, K; Diels, Kurt

1966-01-01

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

Vacuum Technology

Energy Technology Data Exchange (ETDEWEB)

Biltoft, P J

2004-10-15

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

Figure del desiderio: l'amore fra distruzione e sublime

Directory of Open Access Journals (Sweden)

Mabel Franzone

2005-03-01

Full Text Available Attraverso due racconti di Cortázar, l'analisi di due figure del desiderio ci permette esplorare due estremi seguendo una verticalità. La distruzione, doppio tenebroso della nostra anima, ci rivela un erotismo legato alla morte e al desiderio morboso di possedere l'Altro; il suo contraltare è un'ascesa vertiginosa accompagnata da un godimento estetico, dall'amore sublime prossimo all'esperienza mistica che si concluderà con una discesa progressiva e nel rispetto di questo Altro. La creazione letteraria si presenta come uno sfogo alle nostre angosce, che sono anche una sorta d'espressione dell'erotismo.

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

International Nuclear Information System (INIS)

Cooperstein, G.

1988-01-01

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

The 11th Australian Conference on Nuclear Techniques of Analysis and the 5th Vacuum Society of Australia Congress. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-07-01

This publication contains summaries submitted by the participants at the joint AINSE Conference on Nuclear Techniques of Analysis and the Vacuum Society of Australia Congress. Topics covered include: ion beam analysis and its applications; structural chemical analysis of various materials and thin films, environmental studies, accelerator mass spectrometry, ion implantation. The programme of the meeting and list of participants are also included in this volume. Each of the presentations was separately indexed.

The 11th Australian Conference on Nuclear Techniques of Analysis and the 5th Vacuum Society of Australia Congress. Proceedings

International Nuclear Information System (INIS)

1999-01-01

This publication contains summaries submitted by the participants at the joint AINSE Conference on Nuclear Techniques of Analysis and the Vacuum Society of Australia Congress. Topics covered include: ion beam analysis and its applications; structural chemical analysis of various materials and thin films, environmental studies, accelerator mass spectrometry, ion implantation. The programme of the meeting and list of participants are also included in this volume. Each of the presentations was separately indexed

Non-platinum nanocatalyst on porous nitrogen-doped carbon fabricated by cathodic vacuum arc plasma technique

Energy Technology Data Exchange (ETDEWEB)

Sirirak, Reungruthai [Material Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sarakonsri, Thapanee, E-mail: tsarakonsri@gmail.com [Material Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Medhesuwakul, Min [Plasma & Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2015-11-30

Highlights: • High surface area porous coral-like nitrogen-doped carbon (NC) and non-platinum nanocatalysts were fabricated on proton exchange membrane using the cathodic vacuum arc plasma (CVAP) technique. • It is a one-step catalysts preparation directly on nafion proton exchange membrane. This CVAP technique is the first new method that was applied in a polymer electrolyte membrane fuel cells (PEMFCs) catalysts preparation. • Due to these excellent characteristics of nitrogen-doped carbon, it is expected to exhibit a good catalyst supporter for PEMFC. • In addition, the Fe–NC catalysts fabricated via this CVAP technique are sphere-like nanoparticle and well disperse on coral-like NC film, which particularity exhibits that these prepared catalysts ought to be a good oxygen reduction reaction (ORR) catalyst for PEMFC. • This approach can be extended to the synthesis of other non-platinum ORR catalyst for broad range applications in energy conversion. - Abstract: Polymer electrolyte membrane fuel cells (PEMFCs) convert chemical energy directly into electrical energy where catalysts composing of non-noble transition metals, nitrogen, and carbon compounds are the most promising materials to replace the expensive platinum catalysts for oxygen reduction reaction (ORR). In this research, cathodic vacuum arc plasma (CVAP) technique was used to fabricate porous nitrogen doped carbon (NC) and non-platinum catalyst on porous NC (Fe–NC) directly on ion exchange membrane for being used as an ORR catalyst at the cathode. The porous NC layer was fabricated on silicon wafer at 0.05 mTorr, 0.1 mTorr, 0.5 mTorr, 1 mTorr, and 5 mTorr of nitrogen gas inlet. The AFM, and SEM images are observed to be regularly big with quite high hillocks and thin NC layers; these results indicate that the optimum process pressure of nitrogen gas inlet is 5 mTorr for porous NC fabrication. The SEM–EDS detects Fe, N, and C elements in the prepared catalysts, and the XRD pattern reviews

Non-platinum nanocatalyst on porous nitrogen-doped carbon fabricated by cathodic vacuum arc plasma technique

International Nuclear Information System (INIS)

Sirirak, Reungruthai; Sarakonsri, Thapanee; Medhesuwakul, Min

2015-01-01

Highlights: • High surface area porous coral-like nitrogen-doped carbon (NC) and non-platinum nanocatalysts were fabricated on proton exchange membrane using the cathodic vacuum arc plasma (CVAP) technique. • It is a one-step catalysts preparation directly on nafion proton exchange membrane. This CVAP technique is the first new method that was applied in a polymer electrolyte membrane fuel cells (PEMFCs) catalysts preparation. • Due to these excellent characteristics of nitrogen-doped carbon, it is expected to exhibit a good catalyst supporter for PEMFC. • In addition, the Fe–NC catalysts fabricated via this CVAP technique are sphere-like nanoparticle and well disperse on coral-like NC film, which particularity exhibits that these prepared catalysts ought to be a good oxygen reduction reaction (ORR) catalyst for PEMFC. • This approach can be extended to the synthesis of other non-platinum ORR catalyst for broad range applications in energy conversion. - Abstract: Polymer electrolyte membrane fuel cells (PEMFCs) convert chemical energy directly into electrical energy where catalysts composing of non-noble transition metals, nitrogen, and carbon compounds are the most promising materials to replace the expensive platinum catalysts for oxygen reduction reaction (ORR). In this research, cathodic vacuum arc plasma (CVAP) technique was used to fabricate porous nitrogen doped carbon (NC) and non-platinum catalyst on porous NC (Fe–NC) directly on ion exchange membrane for being used as an ORR catalyst at the cathode. The porous NC layer was fabricated on silicon wafer at 0.05 mTorr, 0.1 mTorr, 0.5 mTorr, 1 mTorr, and 5 mTorr of nitrogen gas inlet. The AFM, and SEM images are observed to be regularly big with quite high hillocks and thin NC layers; these results indicate that the optimum process pressure of nitrogen gas inlet is 5 mTorr for porous NC fabrication. The SEM–EDS detects Fe, N, and C elements in the prepared catalysts, and the XRD pattern reviews

Time Variability of the Dust Sublimation Zones in Pre-Main Sequence Disk Systems

Science.gov (United States)

Sitko, Michael L.; Carpenter, W. J.; Grady, C. A.; Russel, R. W.; Lynch, D. K.; Rudy, R. J.; Mazuk, S. M.; Venturini, C. C.; Kimes, R. L.; Beerman, L. C.;

Project management techniques used in the European Vacuum Vessel sectors procurement for ITER

Energy Technology Data Exchange (ETDEWEB)

Losasso, Marcello, E-mail: marcello.losasso@f4e.europa.eu [Fusion for Energy (F4E), Barcelona (Spain); Ortiz de Zuniga, Maria; Jones, Lawrence; Bayon, Angel; Arbogast, Jean-Francois; Caixas, Joan; Fernandez, Jose; Galvan, Stefano; Jover, Teresa [Fusion for Energy (F4E), Barcelona (Spain); Ioki, Kimihiro [ITER Organisation, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Lewczanin, Michal; Mico, Gonzalo; Pacheco, Jose Miguel [Fusion for Energy (F4E), Barcelona (Spain); Preble, Joseph [ITER Organisation, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Stamos, Vassilis; Trentea, Alexandru [Fusion for Energy (F4E), Barcelona (Spain)

2012-08-15

Highlights: Black-Right-Pointing-Pointer File name contains the directory tree structure with a string of three-letter acronyms, thereby enabling parent directory location when confronted with orphan files. Black-Right-Pointing-Pointer The management of the procurement procedure was carried out in an efficient and timely manner, achieving precisely the contract placement date foreseen at the start of the process. Black-Right-Pointing-Pointer The contract start-up has been effectively implemented and a flexible project management system has been put in place for an efficient monitoring of the contract. - Abstract: The contract for the seven European Sectors of the ITER Vacuum Vessel (VV) was placed at the end of 2010 with a consortium of three Italian companies. The task of placing and the initial take-off of this large and complex contract, one of the largest placed by F4E, the European Domestic Agency for ITER, is described. A stringent quality controlled system with a bespoke Vacuum Vessel Project Lifecycle Management system to control the information flow, based on ENOVIA SmarTeam, was developed to handle the storage and approval of Documentation including links to the F4E Vacuum Vessel system and ITER International Organization System interfaces. The VV Sector design and manufacturing schedule is based on Primavera software, which is cost loaded thus allowing F4E to carry out performance measurement with respect to its payments and commitments. This schedule is then integrated into the overall Vacuum Vessel schedule, which includes ancillary activities such as instruments, preliminary design and analysis. The VV Sector Risk Management included three separate risk analyses from F4E and the bidders, utilizing two different methodologies. These efforts will lead to an efficient and effective implementation of this contract, vital to the success of the ITER machine, since the Vacuum Vessel is the biggest single work package of Europe's contribution to ITER and

How to Kill a Journalism School: The Digital Sublime in the Discourse of Discontinuance

Science.gov (United States)

McDevitt, Michael; Sindorf, Shannon

2012-01-01

The authors argue that journalism's uncertain identity in academia has made it vulnerable to unreflective instrumentalism in the digital era. They show how instrumentalism intertwined with the digital sublime constitutes a rhetorically resonate rationale for closing a journalism school. Evidence comes from documents and testimony associated with…

Mechanochemical synthesis of 1-stanna-2,3-dicarba-closo-dodecaborane SnB9C2H11

International Nuclear Information System (INIS)

Volkov, V.V.; Myakishev, K.G.; Solomatina, L.Ya.

1990-01-01

The possibility of synthesis of 1-stanna-2, 3-dicarba-dodecaborane (2), SnB 9 C 2 H 11 by the mechanical activation of solid mixtures of CsB 9 C 2 H 12 , NaH and SnCl 2 has been studied. These solid phase mechano-chemical reactions were performed in vacuum vibration mills without any liquid solvents at room temperature. Crystalline SnB 9 C 2 H 11 was produced by sublimation in vacuum at 140 deg C. Yioeld of the sublimate was 3-6%

Effect of pressure on the vacuum cooling of iceberg lettuce

Energy Technology Data Exchange (ETDEWEB)

Ozturk, Hande Mutlu [Pamukkale University, Food Engineering Department, Faculty of Engineering, Denizli (Turkey); Ozturk, Harun Kemal [Pamukkale University, Mechanical Engineering Department, Faculty of Engineering, 20070 Kinikli, Denizli (Turkey)

2009-05-15

Vacuum cooling is known as a rapid evaporative cooling technique for any porous product which has free water. The aim of this paper is to apply vacuum cooling technique to the cooling of the iceberg lettuce and show the pressure effect on the cooling time and temperature decrease. The results of vacuum cooling are also compared with conventional cooling (cooling in refrigerator) for different temperatures. Vacuum cooling of iceberg lettuce at 0.7 kPa is about 13 times faster than conventional cooling of iceberg lettuce at 6 C. It has been also found that it is not possible to decrease the iceberg lettuce temperature below 10 C if vacuum cooling method is used and vacuum pressure is set to 1.5 kPa. (author) [French] Le refroidissement sous vide est connu comme une technique evaporative rapide refroidissant pour n'importe quel produit poreux qui a de l'eau libre. Le but de ce papier est d'appliquer le refroidissement sous vide pour le refroidissement de la laitue et examiner l'effet de la pression sur le temps de refroidissement et la diminution de temperature. Les resultats de refroidissement sous vide sont aussi compares avec le refroidissement conventionnel (refroidissement dans le refrigerateur) pour les differentes temperatures. Le refroidissement a vide de laitue a 0.7 kPa est environ 13 fois plus vite que le refroidissement conventionnel de laitue croquante a 6 C. Il a ete aussi constate qu'il n'est pas possible de diminuer la temperature de laitue ci-dessous 10 C si le refroidissement sous vide est utilise comme methode et la pression a vide est montree a 1.5 kPa. (orig.)

Vacuum drying plant for evaporator concentrates

International Nuclear Information System (INIS)

Benavides, E.

2001-01-01

Volume reduction systems applied to evaporator concentrates in PWR and BWR save a significant amount of drums. The concentration to dry product is a technique that reaches the maximum volume reduction, compared to conventional techniques (cementation, polymerisation). Four Spanish N.P.P. (3 PWR and 1 BWR) have selected ENSA's process by means of fixed ''in drum vacuum drying system''. A 130-litre steel drum is used for drying without any additional requirement except vacuum resistance. This steel drum is introduced into a standard 200-litre drum. Five centimeters concrete shielding cylinder exists between both drums. Final package is classified as 19 GO according to ENRESA's acceptance code (dry waste with 5 cm concrete between 130-l and 200-l drum). The generation of cemented waste in five N.P.P. versus dried waste will be reduced 83%. This reduction will save a considerable amount in disposal costs. (authors)

Verdad sublime y madre asesina en Christine V., versión de Marguerite Duras

Directory of Open Access Journals (Sweden)

Juliana González Holguín

2016-01-01

Full Text Available Todo relato es ficción, versión y, así mismo, verdad, bajo una u otra concepción de la misma, es decir, desde una perspectiva que se enfoca según la intención y la subjetividad de uno o más actores, de uno o más narradores. El texto de Marguerite Duras intitulado Sublime forcément sublime Christine V. involucra, por su contenido y su contexto, varias versiones que contrastan y se interrogan entre sí. La escritora se posiciona de tal manera que, a través de recursos propios del oficio literario, desentraña una verdad que puede no ajustarse a la realidad o al saber, pero que nos enfrenta a los límites de lo pulsional y lo ominoso.

Titanium sublimation pumping systems and performances on the Tandem Mirror Experiment-Upgrade (TMX-U)

International Nuclear Information System (INIS)

Pico, R.E.

1986-01-01

This paper presents a brief history of the TMX-U Titanium Sublimation Pumping process (gettering). Titanium sublimation pumps offer an economical means of pumping chemically active gases (especially hydrogen) at high speeds, and serves as additional pumps, along with liquid nitrogen-cooled panels, to provide pumping during each physics experiment. Because of the size of the system, a complex computer program was written which is run-time compiled, and then run by the computer. With the multi-tasking capability of the computer, five programs are used in operation and run simultaneously. All getter wire history, deposition, and system notes are stored on the external disc drive. The progress and performance in the four years the system has been used, two year manually controlled, and two computer controlled with be covered. Emphasis on the computer control system and its by-products, which enhance the operation of the TMX-U, will be the subject of this paper

Ülev ei Kivisildniku luules. Üks lugemisviis. The Sublime „No” in Kivisildnik’s Poetry: A Way of Reading

Directory of Open Access Journals (Sweden)

Leo Luks

2012-04-01

Full Text Available This article aims toward a phenomenological interpretation of the unmediated experience of reading Sven Kivisildnik’s poetry. As the basic theoretical thesis of the article, I assert that there is always an inherent negativity in the feeling of the sublime, since this feeling is caused by unrepresentable experience. Likewise, I claim that this negativity is not merely a lack in aesthetic representation, but that it has deep ontological meaning in itself. I make connections between the inherent negativity in the feeling of the sublime and the concept of failure of linguistic utterance worked out by Jaan Undusk, Jaak Tomberg and Jüri Lipping. I come to the conclusion that the „no” in the feeling of sublimity is given to us in unmediated form. The practical (or applied intention of this article is to show that the dominant sociocentric interpretation of Kivisildnik’s poetry is one-sided and limiting. From the theoretical positions I have worked out, I outline the fundamental motifs of Kivisildnik’s poetry, and by means of examples drawn from the text, demonstrate how the „no” of the sublime is found there. I come to the conclusion that the dominant direction in Kivisildnik’s poetry is destruction. The article consists of an introduction, five sections, and a summary. In the first section („Approaches”, I briefly introduce the phenomenological approach. My position is that the work is always created during the act of reading, as the outcome of the union of text and reader. However, I leave the reader as subject open to definition, leaving it to drift as it were, since I am sceptical about the possibility of defining the subject. I do not claim that the sublime is the only possible conceptual framework for understanding poetry; rather, I consider the sublime as one proper theoretical metaphor for conceptualizing personal experience of reading. In the second section of the article („Defining poetry”, I make use of Rein Raud�

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

International Nuclear Information System (INIS)

Ayhan, T.; Al-Madani, H.

2007-01-01

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

Dynamic Low-Vacuum Scanning Electron Microscope Freeze Drying Observation for Fresh Water Algae

International Nuclear Information System (INIS)

Mohsen, H.T.; Ghaly, W.A.; Zahran, N.F.; Helal, A.I.

2010-01-01

A new perpetration method for serving in dynamic examinations of the fresh water algae is developed in connection with the Low-Vacuum Scanning Electron Microscope (LV-SEM) freeze drying technique. Specimens are collected from fresh water of Ismailia channel then transferred directly to freeze by liquid nitrogen and dried in the chamber of the scanning electron microscope in the low vacuum mode. Scanning electron micrographs revealed that the drying method presented the microstructure of algae. Dehydration in a graded ethanol series is not necessary in the new method. Dried algae specimen is observed in SEM high vacuum mode after conductive coating at higher resolution. Low-vacuum SEM freeze drying technique is a simple, time-saving and reproducible method for scanning electron microscopy that is applicable to various aquatic microorganisms covered with soft tissues.

Conditioning of the vacuum chamber of the Tokamak Novillo

International Nuclear Information System (INIS)

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

1992-03-01

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

A comparative study of structural and mechanical properties of Al–Cu composites prepared by vacuum and microwave sintering techniques

Directory of Open Access Journals (Sweden)

Penchal Reddy Matli

2018-04-01

Full Text Available In this paper, the aluminum metal matrix composite reinforced with copper particulates (3, 6 and 9 vol.% were fabricated by high energy ball milling, followed by vacuum sintering (VS and microwave sintering techniques (MS separately. The effects of Cu content and preparation methods on the microstructure and compression mechanical behavior of Al–Cu matrix composites were investigated. The microstructural characterizations revealed a homogeneous distribution of Cu particles in the Al matrix and also fine microstructures of microwave sintered samples. The microwave sintered specimen exhibited the highest hardness and better mechanical properties compared to vacuum sintered specimens. Furthermore, the hardness and compressive strength increased 137.2% and 30.3% for the microwave sintered Al–9 vol.% Cu composite, respectively. The increase in mechanical properties with the increasing volume fraction of Cu particulates can be ascribed to the presence of harder Cu particles reinforcement. The developed materials of the microwave sintered Al–Cu composite in this investigation could be successfully used for industrial applications due to improved mechanical properties. Keywords: Al matrix composites, Microwave sintering, Microstructure, Mechanical behavior

Thermodynamic study of alkane-α,ω-diamines - evidence of odd-even pattern of sublimation properties

Czech Academy of Sciences Publication Activity Database

Fulem, Michal; Růžička, K.; Červinka, C.; Bazyleva, A.; Della Gatta, G.

2014-01-01

Roč. 371, Jun (2014), s. 93-105 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : alkane-diamines * odd–even effect * vapor pressure * sublimation and vaporization thermodynamic properties * statistical thermodynamics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.200, year: 2014

Effect of Coil Current on the Properties of Hydrogenated DLC Coatings Fabricated by Filtered Cathodic Vacuum Arc Technique

Science.gov (United States)

Liao, Bin; Ouyang, Xiaoping; Zhang, Xu; Wu, Xianying; Bian, Baoan; Ying, Minju; Jianwu, Liu

2018-01-01

We successfully prepared hydrogenated DLC (a-C:H) with a thickness higher than 25 μm on stainless steel using a filtered cathode vacuum arc (FCVA) technique. The structural and mechanical properties of DLC were systematically analyzed using different methods such as x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, Vickers hardness, nanohardness, and friction and wear tests. The effect of coil current on the arc voltage, ion current, and mechanical properties of resultant films was systematically investigated. The novelty of this study is the fabrication of DLC with Vickers hardness higher than 1500 HV, in the meanwhile with the thickness higher than 30 μm through varying the coil current with FCVA technique. The results indicated that the ion current, deposition rate, friction coefficient, and Vickers hardness of DLC were significantly affected by the magnetic field inside the filtered duct.

Vacuum mechatronics

Science.gov (United States)

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

1989-01-01

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

Piezoelectric crystal microbalance measurements of enthalpy of sublimation of C2-C9 dicarboxylic acids

Science.gov (United States)

Dirri, F.; Palomba, E.; Longobardo, A.; Zampetti, E.

2016-02-01

We present here a novel experimental set-up that is able to measure the enthalpy of sublimation of a given compound by means of piezoelectric crystal microbalances (PCMs). The PCM sensors have already been used for space measurements, such as for the detection of organic and non-organic volatile species and refractory materials in planetary environments. In Earth atmospherics applications, PCMs can be also used to obtain some physical-chemical processes concerning the volatile organic compounds (VOCs) present in atmospheric environments. The experimental set-up has been developed and tested on dicarboxylic acids. In this work, a temperature-controlled effusion cell was used to sublimate VOC, creating a molecular flux that was collimated onto a cold PCM. The VOC recondensed onto the PCM quartz crystal, allowing the determination of the deposition rate. From the measurements of deposition rates, it has been possible to infer the enthalpy of sublimation of adipic acid, i.e. ΔHsub : 141.6 ± 0.8 kJ mol-1, succinic acid, i.e. 113.3 ± 1.3 kJ mol-1, oxalic acid, i.e. 62.5 ± 3.1 kJ mol-1, and azelaic acid, i.e. 124.2 ± 1.2 kJ mol-1. The results obtained show an accuracy of 1 % for succinic, adipic, and azelaic acid and within 5 % for oxalic acid and are in very good agreement with previous works (within 6 % for adipic, succinic, and oxalic acid and within 11 % or larger for azelaic acid).

The political sublime. reading Kok Nam, Mozambican photographer (1939-2012

Directory of Open Access Journals (Sweden)

Rui Assubuji

Full Text Available Kok Nam began his photographic career at Studio Focus in Lourenco Marques in the 1950s, graduated to the newspaper Noticias and joined Tempo magazine in the early 1970s. Most recently he worked at the journal Savana as a photojournalist and later director. This article opens with an account of the relationship that developed between Kok Nam and the late President Samora Machel, starting with the photographer's portrait of Machel in Nachingwea in November 1974 before Independence. It traces an arc through the Popular Republic (1976-1990 from political revelation at its inception to the difficult years of civil war and Machel's death in the plane crash at Mbuzini in 1986. The article then engages in a series of photo-commentaries across a selection of Kok Nam's photographs, several published in their time but others selected retrospectively by Kok Nam for later exhibition and circulation. The approach taken is that of 'association', exploring the connections between the photographs, their histories both then and in the intervening years and other artifacts and mediums of cultural expression that deal with similar issues or signifiers picked up in the images. Among the signifiers picked up in the article are soldiers, pigs, feet, empty villages, washing, doves and bridges. The central argument is that Kok Nam participated with many others in a kind of collective hallucination during the Popular Republic, caught up in the 'political sublime'. Later Kok Nam shows many signs of a photographic 'second thinking' that sought out a more delicate sublime in his own archive.

Vapor pressures and standard molar enthalpies, entropies, and Gibbs free energies of sublimation of 2,4- and 3,4-dinitrobenzoic acids

International Nuclear Information System (INIS)

Vecchio, Stefano; Brunetti, Bruno

2009-01-01

The vapor pressures of the solid and liquid 2,4- and 3,4-dinitrobenzoic acids were determined by torsion-effusion and thermogravimetry under both isothermal and non-isothermal conditions, respectively. From the temperature dependence of vapor pressure derived by the experimental torsion-effusion and thermogravimetry data the molar enthalpies of sublimation Δ cr g H m 0 ( ) and vaporization Δ l g H m 0 ( ) were determined, respectively, at the middle of the respective temperature intervals. The melting temperatures and the molar enthalpies of fusion of these compounds were measured by d.s.c. Finally, the results obtained by all the methods proposed were corrected at the reference temperature of 298.15 K using the estimated heat capacity differences between gas and liquid for vaporization experiments and the estimated heat capacity differences between gas and solid for sublimation experiments. Therefore, the averages of the standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs free energies of sublimation at 298.15 K, have been derived.

Experimental and molecular dynamics simulation study of the sublimation energetics of cyclopentadienyltricarbonylmanganese (Cymantrene).

Science.gov (United States)

Picciochi, Ricardo; Canongia Lopes, José N; Diogo, Hermínio P; Minas da Piedade, Manuel E

2008-10-16

The standard molar enthalpy of sublimation of monoclinic cyclopentadienyltricarbonylmanganese, Mn(eta (5)-C 5H 5)(CO) 3, at 298.15 K, was determined as Delta sub H m (o)[Mn(eta (5)-C 5H 5)(CO) 3] = 75.97 +/- 0.37 kJ x mol (-1) from Knudsen effusion and Calvet-drop microcalorimetry measurements, thus considerably improving the very large inaccuracy (>10 kJ x mol (-1)) of the published data. The obtained value was used to assess the extension of the OPLS-based all-atom force field we previously developed for iron metallocenes to manganese organometallic compounds. The modified force field was able to reproduce the volumetric properties (density and unit-cell volume) of crystalline Mn(eta (5)-C 5H 5)(CO) 3 with a deviation of 0.6% and the experimentally determined enthalpy of sublimation with an accuracy of 1 kJ x mol (-1). The interaction (epsilon) and atomic-diameter (sigma) parameters of the Lennard-Jones (12-6) potential function used to calculate dispersion contributions within the framework of the force field were found to be transferable from iron to manganese.

Note: reliable and reusable ultrahigh vacuum optical viewports.

Science.gov (United States)

Arora, P; Sen Gupta, A

2012-04-01

We report a simple technique for the realization of ultrahigh vacuum optical viewports. The technique relies on using specially designed thin copper knife-edges and using a thin layer of Vacseal(®) on tip of the knife-edges between the optical flat and the ConFlat(®) (CF) flange. The design of the windows is such that it gives uniform pressure on the flat without breaking it. The assembled window is a complete unit, which can be mounted directly onto a CF flange of the vacuum chamber. It can be removed and reused without breaking the window seal. The design is reliable as more than a dozen such windows have survived several bake out and cooling cycles and have been leak tested up to 10(-11) Torr l/s level with a commercial Helium leak detector. The advantages of this technique are ease of assembly and leak proof sealing that survives multiple temperature cycling making the windows reliable and reusable. © 2012 American Institute of Physics

Sublimator Driven Coldplate Engineering Development Unit Test Results and Development of Second Generation SDC

Science.gov (United States)

Stephan, Ryan A.; Sheth, Rubik B.

2009-01-01

The Sublimator Driven Coldplate (SDC) is a unique piece of thermal control hardware that has several advantages over a traditional thermal control scheme. The principal advantage is the possible elimination of a pumped fluid loop, potentially increasing reliability and reducing complexity while saving both mass and power. Furthermore, the Integrated Sublimator Driven Coldplate (ISDC) concept couples a coolant loop with the previously described SDC hardware. This combination allows the SDC to be used as a traditional coldplate during long mission phases. The previously developed SDC technology cannot be used for long mission phases due to the fact that it requires a consumable feedwater for heat rejection. Adding a coolant loop also provides for dissimilar redundancy on the Altair Lander ascent module thermal control system, which is the target application for this technology. Tests were performed on an Engineering Development Unit at NASA s Johnson Space Center to quantify and assess the performance of the SDC. Correlated thermal math models were developed to help explain the test data. The paper also outlines the preliminary results of an ISDC concept being developed.

Uranium hexaflouride freezer/sublimer process simulator/trainer

International Nuclear Information System (INIS)

Carnal, C.L.; Belcher, J.D.; Tapp, P.A.; Ruppel, F.R.; Wells, J.C.

1991-01-01

This paper describes a software and hardware simulation of a freezer/sublimer unit used in gaseous diffusion processing of uranium hexafluoride (UF 6 ). The objective of the project was to build a plant simulator that reads control signals and produces plant signals to mimic the behavior of an actual plant. The model is based on physical principles and process data. Advanced Continuous Simulation Language (ACSL) was used to develop the model. Once the simulation was validated with actual plant process data, the ACSL model was translated into Advanced Communication and Control Oriented Language (ACCOL). A Bristol Babcock Distributed Process Controller (DPC) Model 3330 was the hardware platform used to host the ACCOL model and process the real world signals. The DPC will be used as a surrogate plant to debug control system hardware/software and to train operators to use the new distributed control system without disturbing the process. 2 refs., 4 figs

Origin and effective reduction of inversion domains in aluminum nitride grown by a sublimation method

Science.gov (United States)

Shigetoh, Keisuke; Horibuchi, Kayo; Nakamura, Daisuke

2017-11-01

Owing to the large differences in the chemical properties between Al and N polarities in aluminum nitride (AlN), the choice of the polar direction for crystal growth strongly affects not only the quality but also the shape (facet formation) of the grown crystal. In particular, N-polar (0 0 0 -1) has been considered to be a more preferable direction than Al-polar (0 0 0 1) for sublimation growth because compared to Al-polar (0 0 0 1), N-polar (0 0 0 -1) exhibits better stability at high growth rate (high supersaturation) conditions and enables easier lateral enlargement of the crystal. However, some critical growth conditions induce polarity inversion and hinder stable N-polar growth. Furthermore, the origin of the polarity inversion in AlN growth by the sublimation method is still unclear. To ensure stable N-polar growth without polarity inversion, the formation mechanism of the inversion domain during AlN sublimation growth must be elucidated. Therefore, herein, we demonstrate homoepitaxial growth on an N-polar seed and carefully investigate the obtained crystal that shows polarity inversion. Annular bright-field scanning transmission electron microscopy reveals that polarity is completely converted to the Al polarity via the formation of a 30 nm thick mixed polar layer (MPL) just above the seed. Moreover, three-dimensional atom probe tomography shows the segregation of the oxygen impurities in the MPL with a high concentration of about 3 atom%. Finally, by avoiding the incorporation of oxygen impurity into the crystal at the initial stage of the growth, we demonstrate an effective reduction (seven orders of magnitude) of the inversion domain boundary formation.

Rigidity of generalized Bach-flat vacuum static spaces

Science.gov (United States)

Yun, Gabjin; Hwang, Seungsu

2017-11-01

In this paper, we study the structure of generalized Bach-flat vacuum static spaces. Generalized Bach-flat metrics are considered as extensions of both Einstein and Bach-flat metrics. First, we prove that a compact Riemannian n-manifold with n ≥ 4 which is a generalized Bach-flat vacuum static space is Einstein. A generalized Bach-flat vacuum static space with the potential function f having compact level sets is either Ricci-flat or a warped product with zero scalar curvature when n ≥ 5, and when n = 4, it is Einstein if f has its minimum. Secondly, we consider critical metrics for another quadratic curvature functional involving the Ricci tensor, and prove similar results. Lastly, by applying the technique developed above, we prove Besse conjecture when the manifold is generalized Bach-flat.

MEA vacuum system

International Nuclear Information System (INIS)

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

1984-01-01

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

On the fermion pair production in the process of metastable vacuum decay

International Nuclear Information System (INIS)

Lavrelashvili, G.V.; Rubakov, V.A.; Tinyakov, P.G.

1985-01-01

Production of fermion pairs during the tunneling process leading to the decay of metastable vacuum is considered. The technique based on non-unitary Bogolyubov transformations is developed and formulae for fermionic spectrum are obtained. As an example, the spectrum of fermionic pairs produced during the homogeneous decay of metastable vacuum is evaluated

Insulation vacuum and beam vacuum overpressure release

CERN Document Server

Parma, V

2009-01-01

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

Vacuum system for Advanced Test Accelerator

International Nuclear Information System (INIS)

Denhoy, B.S.

1981-01-01

The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10 -6 torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing

Vacuum system for Advanced Test Accelerator

Energy Technology Data Exchange (ETDEWEB)

Denhoy, B.S.

1981-09-03

The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10/sup -6/ torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing.

CERN's vacuums honoured to the full

CERN Multimedia

2002-01-01

CERN's Cristoforo Benvenuti is awarded one of the most prestigious prizes in the world of vacuum techniques     Because we constantly run into such individuals, we tend to forget that CERN has specialists with world reputations. It takes the international prizes they win to remind us of the fact. One such prize, the American Vacuum Society (AVS)'s Gaede-Langmuir Award for 2002, has gone to Cristoforo Benvenuti, Leader of the Surfaces and Materials Technologies Group in EST Division. The award, conferred once every two years, is one of the leading prizes in the vacuum field. By coincidence, its very first winner was Pierre Auger, one of CERN's founding fathers, back in 1978. Cristoforo Benvenuti, a senior physicist who joined CERN in 1966, has been singled out for his work on getter technologies. These technologies made their name at CERN with the coming of LEP, where they were used for pumping the machine. Getter is a material with the property of capturing gas molecules and thereby actin...

Study of a micro-sublimation apparatus with removal of the vapours by pumping; application to the analysis of fluorinated products (1963)

International Nuclear Information System (INIS)

Delvalle, P.

1963-01-01

Micro-sublimation analysis presents definite advantages both from the qualitative and quantitative points of view. An automatic micro-sublimation analysis apparatus has been developed for the analysis of fluorinated products (ClF 3 , HF, UF 6 , etc.) but this is only one particular application of a method which has a far wider field of possible applications. We give first the most favorable conditions for the operation of such an apparatus. These conditions are the use of a detector which is linear and independent of the nature of the gas, the flow of the sublimed vapours in the conditions of molecular flow, and finally a reproducible and linear re-heating of the separating trap. The apparatus thus built has the advantage of yielding any analysis without prior calibration. It also makes possible the easy identification of an unknown product by the determination of its vapour pressure curve and its molecular weight. The analysis of fluorinated products with this apparatus has shown that the experimental results agree well with what is expected. (author) [fr

Laboratory studies of the growth, sublimation, and light- scattering properties of single levitated ice particles

Science.gov (United States)

Bacon, Neil Julian

2001-12-01

I describe experiments to investigate the properties of microscopic ice particles. The goal of the work was to measure parameters that are important in cloud processes and radiative transfer, using a novel technique that avoids the use of substrates. The experiments were conducted in two separate electrodynamic balance chambers. Single, charged ice particles were formed from frost particles or from droplets frozen either homogeneously or heteroge neously with a bionucleant. The particles were trapped at temperatures between -38°C and -4°C and grown or sublimated according to the temperature gradient in the cham ber. I describe observations of breakup of sublimating frost particles, measurements of light scattering by hexagonal crystals, and observations of the morphology of ice particles grown from frozen water droplets and frost particles. The breaking strength of frost particles was an order of magnitude less than that of bulk ice. Light scattering features not previously observed were analyzed and related to crystal dimension. Initial results from a computer model failed to reproduce these features. The widths of scattering peaks suggest that surface roughness may play a role in determining the angular distribution of scattered light. Ice particle mass evolution was found to be consistent with diffusion- limited growth. Crystals grown slowly from frozen droplets adopted isometric habits, while faster growth resulted in thin side-planes, although there was not an exact correspondence between growth conditions and particle morphology. From the morphological transition, I infer lower limits for the critical supersaturation for layer nucleation on the prism face of 2.4% at -15°C, 4.4% at -20°C, and 3.1% at -25°C. Analytic expressions for the size dependence of facet stability are developed, indicating a strong dependence of stability on both crystal size and surface kinetics, and compared with data. I discuss the role of complex particle morphologies in

Local effects of the quantum vacuum in Lorentz-violating electrodynamics

Science.gov (United States)

Martín-Ruiz, A.; Escobar, C. A.

2017-02-01

The Casimir effect is one of the most remarkable consequences of the nonzero vacuum energy predicted by quantum field theory. In this paper we use a local approach to study the Lorentz violation effects of the minimal standard model extension on the Casimir force between two parallel conducting plates in the vacuum. Using a perturbative method similar to that used for obtaining the Born series for the scattering amplitudes in quantum mechanics, we compute, at leading order in the Lorentz-violating coefficients, the relevant Green's function which satisfies given boundary conditions. The standard point-splitting technique allow us to express the vacuum expectation value of the stress-energy tensor in terms of the Green's function. We discuss its structure in the region between the plates. We compute the renormalized vacuum stress, which is obtained as the difference between the vacuum stress in the presence of the plates and that of the vacuum. The Casimir force is evaluated in an analytical fashion by two methods: by differentiating the renormalized global energy density and by computing the normal-normal component of the renormalized vacuum stress. We compute the local Casimir energy, which is found to diverge as approaching the plates, and we demonstrate that it does not contribute to the observable force.

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

International Nuclear Information System (INIS)

Hussain, Z.

1995-08-01

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

Control and calculation of the titanium sublimation pumping speed and re-ionisation in the MAST neutral beam injectors

International Nuclear Information System (INIS)

McAdams, R.

2015-01-01

Highlights: • The titanium sublimation pumps for the MAST neutral beam injectors are described. • Evaporation regimes are established to give constant pumping speed for the titanium sublimation pumps. • The MCNP code is used to calculate the pumping speeds and gas profiles in the neutral beam injectors. • The gas profiles are then used to calculate the level of re-ionisation in the beamline. - Abstract: A high pumping speed is required in neutral beam injectors to minimise re-ionisation of the neutral beams. The neutral beam injectors on MAST use titanium sublimation pumps. These pumps do not have a constant pumping speed; their pumping speed depends on the gettering surface history and on both the integrated and applied gas load. In this paper we describe a method of maintaining a constant pumping speed, through different evaporation schemes, specifically suitable for operations of the MAST neutral beam injector beamlines for both short and relatively long beam pulses by measurement of the pressure in the beamline. In addition the MCNP code is then used to calculate the pumping speed and gas profile in the beamline by adjusting the input pumping speed to match the measured pressure. This allows the resulting gas profile to be used for calculation of the re-ionisation levels and an example is given

Reparation effects of vacuum wound therapy in patients with diabetic foot syndrome

Directory of Open Access Journals (Sweden)

Besedin A.M.

2015-09-01

Full Text Available Vacuum Therapy (Vacuum-assisted closure, VAC - a method of complex therapy which is used to improve the healing of both acute chronic wounds in patients with diabetic foot syndrome. Due to widespread introduction of this technique, unique cell, extracellular and general effects of its use in the treatment of patients with purulent-necrotic complications of diabetic foot syndrome, a technique of vacuum wound therapy has been successfully used in many surgical departments of Ukraine. Despite the diversity of the clinical effects of VAC-therapy and appearance of number of publications, in the domestic and foreign literature physiological basis of this method have not been studied completely. The effectiveness of vacuum therapy explain: the reduction of the size of the wound, the stabilization of the wound environment (due to the removal of inflammatory mediators and cytokines, microdeformation and remodeling of cell, rows reduction of edema, reduction of bacterial contamination, etc. At the same time, mechanisms of blood flow enhancement at different duration of VAC-therapy use, remain unclear its effect on the third phase of wound healing process as well.

Investigation of Non-Vacuum Deposition Techniques in Fabrication of Chalcogenide-Based Solar Cell Absorbers

KAUST Repository

Alsaggaf, Ahmed

2015-07-01

The environmental challenges are increasing, and so is the need for renewable energy. For photovoltaic applications, thin film Cu(In,Ga)(S,Se)2 (CIGS) and CuIn(S,Se)2 (CIS) solar cells are attractive with conversion efficiencies of more than 20%. However, the high-efficiency cells are fabricated using vacuum technologies such as sputtering or thermal co-evaporation, which are very costly and unfeasible at industrial level. The fabrication involves the uses of highly toxic gases such as H2Se, adding complexity to the fabrication process. The work described here focused on non-vacuum deposition methods such as printing. Special attention has been given to printing designed in a moving Roll-to-Roll (R2R) fashion. The results show potential of such technology to replace the vacuum processes. Conversion efficiencies for such non-vacuum deposition of Cu(In,Ga)(S,Se)2 solar cells have exceeded 15% using hazardous chemicals such as hydrazine, which is unsuitable for industrial scale up. In an effort to simplify the process, non-toxic suspensions of Cu(In,Ga)S2 molecular-based precursors achieved efficiencies of ~7-15%. Attempts to further simplify the selenization step, deposition of CuIn(S,Se)2 particulate solutions without the Ga doping and non-toxic suspensions of Cu(In,Ga)Se2 quaternary precursors achieved efficiencies (~1-8%). The contribution of this research was to provide a new method to monitor printed structures through spectral-domain optical coherence tomography SD-OCT in a moving fashion simulating R2R process design at speeds up to 1.05 m/min. The research clarified morphological and compositional impacts of Nd:YAG laser heat-treatment on Cu(In,Ga)Se2 absorber layer to simplify the annealing step in non-vacuum environment compatible to R2R. Finally, the research further simplified development methods for CIGS solar cells based on suspensions of quaternary Cu(In,Ga)Se2 precursors and ternary CuInS2 precursors. The methods consisted of post deposition reactive

Recovery process of wall condition in KSTAR vacuum vessel after temporal machine-vent for repair

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang Pyo, E-mail: kpkim@nfri.er.ke; Hong, Suk-Ho; Lee, Hyunmyung; Song, Jae-in; Jung, Nam-Yong; Lee, Kunsu; Chu, Yong; Kim, Hakkun; Park, Kaprai; Oh, Yeong-Kook

2015-10-15

Highlights: • Efforts have been made to obtain vacuum condition that is essential for the plasma experiments. • For example, the vacuum vessel should be vented to repair in-vessel components such as diagnostic shutter, and PFC damaged by high energy plasma. • Here, we present the recovery process of wall condition in KSTAR after temporal machine-vent for repair. • It is found that an acceptable vacuum condition has been achieved only by plasma based wall conditioning techniques such as baking, GDC, and boronization. • This study was that the proper recovering method of the vacuum condition should be developed according to the severity of the accident. - Abstract: Efforts have been made to obtain vacuum condition that is essential for the plasma experiments. Under certain situations, for example, the vacuum vessel should be vented to repair in-vessel components such as diagnostic shutter, exchange of window for diagnostic equipment, and PFC damaged by high energy plasma. For the quick restart of the campaign, a recovery process was established to make the vacuum condition acceptable for the plasma experiment. In this paper, we present the recovery process of wall condition in KSTAR after temporal machine-vent for repair. It is found that an acceptable vacuum condition has been achieved only by plasma based wall conditioning techniques such as baking, GDC, and boronization. This study was that the proper recovering method of the vacuum condition should be developed according to the severity of the accident.

Venturi Air-Jet Vacuum Ejector For Sampling Air

Science.gov (United States)

Hill, Gerald F.; Sachse, Glen W.; Burney, L. Garland; Wade, Larry O.

1990-01-01

Venturi air-jet vacuum ejector pump light in weight, requires no electrical power, does not contribute heat to aircraft, and provides high pumping speeds at moderate suctions. High-pressure motive gas required for this type of pump bled from compressor of aircraft engine with negligible effect on performance of engine. Used as source of vacuum for differential-absorption CO-measurement (DACOM), modified to achieve in situ measurements of CO at frequency response of 10 Hz. Provides improvement in spatial resolution and potentially leads to capability to measure turbulent flux of CO by use of eddy-correlation technique.

Vacuum mechatronics first international workshop

Energy Technology Data Exchange (ETDEWEB)

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

1989-01-01

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

Distribution of metals in vacuum residuums, asphaltenes and maltenes by PIXE

International Nuclear Information System (INIS)

Romero G, E.T.; Camacho M, V.; Sanchez B, A.C.; Lopez M, J.; Ramirez T, J.J.; Villasenor S, P.; Aspiazu F, J.A.

2001-01-01

The PIXE technique for determining directly the distribution and abundance of trace metals in vacuum residuum, asphaltenes and maltenes separated with n-alkanes (C 5 -C 8 ) is used. The metal content of petroleum derivatives revealed that the vacuum residuum contains iron, aluminium, vanadium and nickel mainly, while that the asphaltenes and maltenes maintain inside of their composition only preferably the vanadium and nickel as majority elements. (Author)

A composite vacuum barrier for the LHC short straight section

International Nuclear Information System (INIS)

Jenny, B.; Rohmig, P.; Uriarte, J.M.

1996-01-01

The lattice of the CERN Large Hadron Collider (LHC) will contain 384 Short Straight Section (SSS) units, one in every 53 m half-cell. The SSS is composed of a twin aperture high-field superconducting quadrupole and of two combined-function corrector magnets operating in pressurized helium at 1.9 K. The SSS cryostat contains also a barrier for sectorisation of the insulation vacuum. The vacuum barrier is mounted between the helium vessel and the vacuum enclosure. Its functions are to limit the extent of eventual helium leaks and to facilitate the leak detection and the pumping-down from atmospheric pressure. During installation of the LHC, the vacuum barrier permits independent testing of the half-cells, thus enabling higher installation rates. In parallel to a conventional barrier made out of austenitic stainless steel, a barrier of composite material was developed, taking advantage of the lower thermal conductivity of glass fibre reinforced epoxy resin, and with the aim of reducing costs for LHC. The thermo-mechanical design together with the conception and the moulding techniques used for the manufacture of the prototype are described. Bonding techniques for the leak tight stainless steel composite interfaces are presented and test results shown. Results on the mechanical performance and on the helium tests carried out on the prototype are given

Magnetically induced vacuum decay

International Nuclear Information System (INIS)

Xue Shesheng

2003-01-01

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

Induced Recrystallization of CdTe Thin Films Deposited by Close-Spaced Sublimation

International Nuclear Information System (INIS)

Mayo, B.

1998-01-01

We have deposited CdTe thin films by close-spaced sublimation at two different temperature ranges. The films deposited at the lower temperature partially recrystallized after CdCl2 treatment at 350C and completely recrystallized after the same treatment at 400C. The films deposited at higher temperature did not recrystallize at these two temperatures. These results confirmed that the mechanisms responsible for changes in physical properties of CdTe films treated with CdCl2 are recrystallization and grain growth, and provided an alternative method to deposit CSS films using lower temperatures

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-08-01

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

Vacuum system for ISABELLE

International Nuclear Information System (INIS)

Hobson, J.P.

1975-01-01

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

Vacuum extraction

DEFF Research Database (Denmark)

Maagaard, Mathilde; Oestergaard, Jeanett; Johansen, Marianne

2012-01-01

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

Calculating infrared contributions to vacuum expectation values of gluonic and quark fields

International Nuclear Information System (INIS)

Arbuzov, B.A.; Boos, E.E.; Turashvili, K.Sh.

1986-01-01

Based on the infrared asymptotics of the lower QCD Green's functions obtained before, we propose a definition and elaborate a technique for calculating non-perturbative vacuum expectations of gluon and quark fields. In our calculations, we use only the known QCD parameters: constituent quark masses, the confining potential slope and the QCD parameter Λ. The values obtained for the vacuum expectations agree well with experiment. (orig.)

Modelling of pulsed electron beam induced graphite ablation: Sublimation versus melting

Science.gov (United States)

Ali, Muddassir; Henda, Redhouane

2017-12-01

Pulsed electron beam ablation (PEBA) has recently emerged as a very promising technique for the deposition of thin films with superior properties. Interaction of the pulsed electron beam with the target material is a complex process, which consists of heating, phase transition, and erosion of a small portion from the target surface. Ablation can be significantly affected by the nature of thermal phenomena taking place at the target surface, with subsequent bearing on the properties, stoichiometry and structure of deposited thin films. A two stage, one-dimensional heat conduction model is presented to describe two different thermal phenomena accounting for interaction of a graphite target with a polyenergetic electron beam. In the first instance, the thermal phenomena are comprised of heating, melting and vaporization of the target surface, while in the second instance the thermal phenomena are described in terms of heating and sublimation of the graphite surface. In this work, the electron beam delivers intense electron pulses of ∼100 ns with energies up to 16 keV and an electric current of ∼400 A to a graphite target. The temperature distribution, surface recession velocity, ablated mass per unit area, and ablation depth for the graphite target are numerically simulated by the finite element method for each case. Based on calculation findings and available experimental data, ablation appears to occur mainly in the regime of melting and vaporization from the surface.

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

Directory of Open Access Journals (Sweden)

Fernanda de Melo RAMOS

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

Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

Energy Technology Data Exchange (ETDEWEB)

Sun, Kai [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Ruixin [Institute of Medical Equipment, Academy of Military and Medical Sciences, No. 106, Wandong Street, Hedong District, Tianjin 300000 (China); Jiang, Wenxue, E-mail: jiangortholivea@sina.cn [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Sun, Yufu [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Hui [Tianjin Medical University General Hospital, No. 154 Anshan Road, Tianjin, TJ 300052 (China)

2016-09-02

In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

International Nuclear Information System (INIS)

Sun, Kai; Li, Ruixin; Jiang, Wenxue; Sun, Yufu; Li, Hui

2016-01-01

In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

Jovellanos en sus escritos íntimos: el paisaje y la emoción estética de lo sublime

Directory of Open Access Journals (Sweden)

Rueda, Ana

2006-12-01

Full Text Available The Diario (Diary foregrounds Jovellanos’s interest in recording Spain and its geography in a historical, statistical, economic and political sense. Like his celebrated report on political economy, the Informe sobre la ley agraria (Report on Agricultural Law, the Diario creates a moral and civil conscience that is profoundly oriented toward the social reform of Spain. Even so, the circumstance of his exile causes his gaze to acquire in this intimate work a quality unlike that of the Report. Jovellanos describes the disturbing beauty of wild landscapes and experiences in his Diary the emotional commotion that Burke (Philosophical Enquiry, 1757 and Kant (Critique of Judgment, 1790 recorded as the sublime. The pages of his Diary on which the word “sublime” and its accompanying emotions appear reveal an anxiety that threatens to undermine Jovellanos’s commitment to societal progress and the power of reason; that is, the suppositions of rational subjectivity that underlay his work as politician and writer. The concept of the sublime introduces narrative spaces of great emotion that reveal an important turn toward an epiphanic subjectivity that in successive decades would come to the fore in Romanticism. However, Jovellanos tempers his enthusiasm. On the threshold of the sublime he takes a step back. His self-alienation appears to prohibit the reader entry into zones of his private person and to frustrate the expectation of the reader of such intimate literature that he will come to know the man. And yet, it is precisely in these moments of hesitation where the reader is allowed access to the diarist´s inner struggle and to his negotiations between his private self and his social persona.El Diario recoge el interés de Jovellanos por consignar España y su geografía en un sentido histórico, estadístico, económico y político. Como hizo constar en su célebre informe de economía política aplicado al estado de la agricultura en la Espa

Enthalpy of sublimation/vaporization of trans-cyclohexyl-1,4-diamine and cis-cyclohexyl-1,2-diamine

International Nuclear Information System (INIS)

Tome, Luciana I.N.; Rosado, Mario T.S.; Nunes, Sandra C.C.; Maria, Teresa M.R.; Canotilho, Joao; Eusebio, M. Ermelinda S.

2007-01-01

The molar enthalpy of sublimation, Δ cr g H m 0 , of trans-cyclohexyl-1,4-diamine and the molar enthalpy of vaporization, Δ l g H m 0 , of cis-cyclohexyl-1,2-diamine, at the temperature 298.15 K, were determined by calorimetry. Δ cr g H m 0 (T=298.15K)=(105.0±0.8)kJ.mol -1 was obtained for the trans-isomer and Δ l g H m 0 (T=298.15K)=(62.2±1.0)kJ.mol -1 for the cis form. The molar enthalpy of fusion of the first compound, at T = 342.1 K, was determined by differential scanning calorimetry. The molar enthalpy of vaporization of the 1,4-isomer was estimated by combining the value of the enthalpy of sublimation with that of the enthalpy of fusion. The values obtained for molar standard enthalpy of vaporization and those available for the enthalpy of the diamines in the gas state were used to calculate the difference between the enthalpies of both compounds in the liquid state

Key composition optimization of meat processed protein source by vacuum freeze-drying technology.

Science.gov (United States)

Ma, Yan; Wu, Xingzhuang; Zhang, Qi; Giovanni, Vigna; Meng, Xianjun

2018-05-01

Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined.

Syringe-vacuum microfluidics: A portable technique to create monodisperse emulsions.

Science.gov (United States)

Abate, Adam R; Weitz, David A

2011-03-16

We present a simple method for creating monodisperse emulsions with microfluidic devices. Unlike conventional approaches that require bulky pumps, control computers, and expertise with device physics to operate devices, our method requires only the microfluidic device and a hand-operated syringe. The fluids needed for the emulsion are loaded into the device inlets, while the syringe is used to create a vacuum at the device outlet; this sucks the fluids through the channels, generating the drops. By controlling the hydrodynamic resistances of the channels using hydrodynamic resistors and valves, we are able to control the properties of the drops. This provides a simple and highly portable method for creating monodisperse emulsions.

Wafer-Level Vacuum Packaging of Smart Sensors.

Science.gov (United States)

Hilton, Allan; Temple, Dorota S

2016-10-31

The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors-"low cost" for ubiquitous presence, and "smart" for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS) integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology.

Wafer-Level Vacuum Packaging of Smart Sensors

Directory of Open Access Journals (Sweden)

Allan Hilton

2016-10-01

Full Text Available The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors—“low cost” for ubiquitous presence, and “smart” for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology.

Cosmic vacuum

International Nuclear Information System (INIS)

Chernin, Artur D

2001-01-01

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

Cosmic vacuum

Energy Technology Data Exchange (ETDEWEB)

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

2001-11-30

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

Cometary nucleus release experiments and ice physics

International Nuclear Information System (INIS)

Huebner, W.F.

1976-01-01

Some physical and chemical processes involved in the evaporation and sublimation of mixtures of frozen gases are discussed. Effects of zero gravity, vacuum and solar radiation are emphasized. Relevant experiments that can be carried out with the aid of the space shuttle are proposed. The ice surface and the space just above the surface, i.e., the physics and chemistry of ice sublimation are mainly considered

Recent results on cleaning and conditioning the ATF vacuum system

International Nuclear Information System (INIS)

Langley, R.A.; Clark, T.L.; Glowienka, J.C.; Goulding, R.H.; Mioduszewski, P.K.; Rasmussen, D.A.; Rayburn, T.F.; Schaich, C.R.; Shepard, T.D.; Simpkins, J.E.; Yarber, J.L.

1990-01-01

Techniques for cleaning and conditioning the vacuum vessel of the Advanced Toroidal Facility (ATF) and its internal components are described. The vacuum vessel cleaning technique combines baking to 150 degree C and glow discharges with hydrogen gas. Chromium gettering is used to further condition the system. The major internal components are the anodized aluminum baffles in the Thomson scattering system, a graphite-shielded ICRF antenna, two graphite limiters, and a diagnostic graphite plate. Three independent heating systems are used to bake some of the major components of the system. The major characteristics used for assessing cleanliness and conditioning progress are the maximum pressure attained during bakeout, the results of gas analysis, and revelant plasma parameters (e.g., time to radiative decay). Details of the various cleaning and conditioning procedures and results are presented

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

Science.gov (United States)

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

2017-03-01

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

Superhard nanocomposite nc-TiC/a-C:H film fabricated by filtered cathodic vacuum arc technique

International Nuclear Information System (INIS)

Wang Yaohui; Zhang Xu; Wu Xianying; Zhang Huixing; Zhang Xiaoji

2008-01-01

Superhard nanocomposite nc-TiC/a-C:H films, with an excellent combination of high elastic recovery, low friction coefficient and good H/E ratio, were prepared by filtered cathodic vacuum arc technique using the C 2 H 2 gas as the precursor. The effect of C 2 H 2 flow rate on the microstructure, phase composition, mechanical and tribological properties of nanocomposite nc-TiC/a-C:H films have been investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy disperse spectroscopy (EDS), microindentation and tribotester measurements. It was observed that the C 2 H 2 flow rate significantly affected the Ti content and hardness of films. Furthermore, by selecting the proper value for C 2 H 2 flow rate, 20 sccm, one can deposit the nanocomposite film nc-TiC/a-C:H with excellent properties such as superhardness (66.4 GPa), high elastic recovery (83.3%) and high H/E ratio (0.13)

Application of ion scattering spectrometers for the observation of process of cleaning of surfaces of materials for vacuum vessel

International Nuclear Information System (INIS)

Akashi, Ken-ya; Miyahara, Akira; Sagara, Akio.

1978-01-01

The impurity gas emitted from the surfaces of vacuum vessels was investigated by using the shadowing effect of the covering atoms. The ion scattering spectrometer used for the experiment consists of an ion source, a test sample, an energy analyzer and an ion detector. The evacuation system comprises a turbomolecular pump, a Ti-sublimation pump and an ion pump. The achieved final gas pressure is 5 x 10 -10 Torr. The ion beam intensity to a sample is 10 micro ampere/cm 2 , and the ion energy is about 1 to 1.5 keV. The quantity of oxygen on the surface of a sample molybdenum was measured in the process of evacuation. The concentration of surface oxygen decreased with the gas pressure of the system. It was found that residual oxygen was observed after the sputter etching with Ar ion impact on the surface. The reason of this residual oxygen was considered. (Kato, T.)

Proceedings of the national symposium on vacuum science and technology and power beams. Volume 2

International Nuclear Information System (INIS)

Venkatramani, N.; Ray, A.K.

1997-11-01

This volume contains the proceedings of the national symposium on vacuum science and technology and power beams. The main topics dealt with are: accelerators and vacuum systems, thin films deposition techniques, lasers and electron power beams and their applications in nuclear facilities. Papers relevant to INIS are indexed separately

Recent advances in vacuum arc ion sources

International Nuclear Information System (INIS)

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

1995-07-01

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

Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

Science.gov (United States)

Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

2016-01-01

In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA. PMID:27023546

Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties.

Science.gov (United States)

Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

2016-03-24

In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

Manufacture of the ALS storage ring vacuum system

International Nuclear Information System (INIS)

Kennedy, K.

1990-11-01

The Advanced Light Source (ALS) storage rings has a 4.9 meter magnetic radius and an antechamber type vacuum chamber. These two requirements makes conventional bent tube manufacturing techniques difficult. The ALS sector vacuum chambers have been made by matching two halves out of aluminum plate and welding at the mid plane. Each of these chambers have over 50 penetrations with metal sealed flanges and seven metal sealed poppet valves which use the chamber wall as the valve seat. The sector chambers are 10 meter long and some features in the chambers must be located to .25 mm. This paper describes how and how successfully these features have been achieved. 2 refs., 5 figs

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

Science.gov (United States)

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

2018-02-01

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

Linear accelerator section alignment in a vacuum chamber

International Nuclear Information System (INIS)

Vengrov, R.M.; Vinogradskij, N.N.; Danil'tsev, E.N.; Iosseliani, D.D.; Kosyak, V.S.; Porubaj, N.I.; Ugarov, S.B.

1989-01-01

Alignment technique for multisectional accelerating structures, that may be used in designing new accelerators for experimental and applied purposes, is described. The accuracy of the alignment of four-chamber resonator sections directly in an accelerator vacuum volume without its depressurization is not less than 100 μm. 8 refs.; 5 figs.; 5 tabs

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

Science.gov (United States)

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

Meteorological conditions associated to high sublimation amounts in semiarid high-elevation Andes decrease the performance of empirical melt models

Science.gov (United States)

Ayala, Alvaro; Pellicciotti, Francesca; MacDonell, Shelley; McPhee, James; Burlando, Paolo

2015-04-01

Empirical melt (EM) models are often preferred to surface energy balance (SEB) models to calculate melt amounts of snow and ice in hydrological modelling of high-elevation catchments. The most common reasons to support this decision are that, in comparison to SEB models, EM models require lower levels of meteorological data, complexity and computational costs. However, EM models assume that melt can be characterized by means of a few index variables only, and their results strongly depend on the transferability in space and time of the calibrated empirical parameters. In addition, they are intrinsically limited in accounting for specific process components, the complexity of which cannot be easily reconciled with the empirical nature of the model. As an example of an EM model, in this study we use the Enhanced Temperature Index (ETI) model, which calculates melt amounts using air temperature and the shortwave radiation balance as index variables. We evaluate the performance of the ETI model on dry high-elevation sites where sublimation amounts - that are not explicitly accounted for the EM model - represent a relevant percentage of total ablation (1.1 to 8.7%). We analyse a data set of four Automatic Weather Stations (AWS), which were collected during the ablation season 2013-14, at elevations between 3466 and 4775 m asl, on the glaciers El Tapado, San Francisco, Bello and El Yeso, which are located in the semiarid Andes of central Chile. We complement our analysis using data from past studies in Juncal Norte Glacier (Chile) and Haut Glacier d'Arolla (Switzerland), during the ablation seasons 2008-09 and 2006, respectively. We use the results of a SEB model, applied to each study site, along the entire season, to calibrate the ETI model. The ETI model was not designed to calculate sublimation amounts, however, results show that their ability is low also to simulate melt amounts at sites where sublimation represents larger percentages of total ablation. In fact, we

Recent results on cleaning and conditioning the ATF vacuum system

International Nuclear Information System (INIS)

Langley, R.A.; Clark, T.L.; Glowienka, J.C.

1989-01-01

Techniques for cleaning and conditioning the vacuum vessel of the Advanced Toroidal Facility (ATF) and its internal components are described. The vacuum vessel cleaning technique combines baking to 150/degree/C and glow discharges with hydrogen gas. Chromium gettering is used to further condition the system. The major internal components are the anodized aluminum baffles in the Thomson scattering system, a graphite-shielded ICRF antenna, two graphite limiters, and a diagnostic graphite plate. Three independent heating systems are used to bake some of the major components of the system. The major characteristics used for assessing cleanliness and conditioning progress are the maximum pressure attained during bakeout, the results of gas analysis, and relevant plasma parameters (e.g., time to radiative decay). Details of the various cleaning and conditioning procedures and results are presented. 5 refs., 8 figs., 3 tabs

Integrated vacuum extraction/pneumatic soil fracturing system for remediation of low permeability soil

International Nuclear Information System (INIS)

Plaines, A.L.; Piniewski, R.J.; Yarbrough, G.D.

1994-01-01

There is wide use of vacuum extraction to remove volatile and semi-volatile organic compounds (VOCs) from unsaturated soil. At sites with soil of low permeability, VOC extraction rates may not be sufficient to meet soil clean-up objectives within the desired time frame. During vacuum extraction in low permeability soil, the diffusion rates of VOCs through the soil matrix may limit VOC removal rates. An increase in the number of subsurface paths for advective flow through the contaminated zone results in a larger mass of contaminant being removed in a shorter time frame, accelerating site remediation. One technique for increasing the number of subsurface flow paths is Terra Vac's process of pneumatic soil fracturing (PSF). In this process, pressurized air is injected into the subsurface, creating micro-fractures for the vacuum extraction system to withdraw contaminants. Similar to hydraulic fracturing techniques long used in the petroleum industry for increasing yield from oil and gas production wells, this technique has applications for soil remediation in low permeability conditions. Two case studies, one in Louisiana at a gasoline service station and one at a manufacturing plant in New York, are presented

A sublimate sorbent for stir-bar sorptive extraction of aqueous endocrine disruptor pesticides for gas chromatography-electron capture detection.

Science.gov (United States)

Huang, Yu-Wen; Lee, Hua Kwang; Shih, Hou-Kuang; Jen, Jen-Fon

2018-06-06

A dumbbell-shaped magnetic stir-bar with sublimate sorbent was prepared for the stir bar sorptive extraction (SBSE) of pesticides in an aqueous sample prior to gas chromatography-micro-electron capture detection (GC-μECD). Cyclododecane (CDD) was coated onto a magnetic stir-bar surface as a sublimate sorbent, and steel balls were placed on both ends to form a dumbbell-shaped magnetic stir-bar for SBSE. Four EDC pesticides including chlorpyrifos, ethion, bromopropylate, and λ-cyhalothrin in aqueous samples were selected as model species to examine the proposed SBSE and the following desorption. The parameters studied were those affecting the extraction efficiencies including the coating (solvent for CDD and thickness), extraction (sample pH, stirring rate, time, and salting out effect), dissolution solvent volume, and the loss of CDD sublimated in air. The maximum extraction efficiency was obtained under the following conditions. The stir bar (with CDD thickness of 5.2 μm) was added into a 10 mL sample solution (at pH 7) for a 20-min extraction at 600 rpm. Then, the stir bar was gently removed from the sample solution, disassembled, and immersed into a 0.2 mL insert tube consisting of 3 μL hexane to dissolve; 1 μL was used for GC-ECD analysis. The linear ranges were 0.005-5 μg L -1 with coefficients of determination ranging from 0.9950 - 0.9994. Detection limits (based on S/N = 3) of the four EDCs were 0.4-4.5 ngL -1 with a relative standard deviation (RSD) of 2.4-6.3%, and quantitation limits (based on S/N = 5) were 1-15 ngL -1 . The relative recoveries of the spiked samples were in the range of 83.2-98.7% with RSDs of 2.1-8.4% in farm field waters. The proposed sublimation sorbent obtained excellent enrichment factors (101-834) and provided a simple, rapid, sensitive, and eco-friendly sample preparation method. Copyright © 2018 Elsevier B.V. All rights reserved.

Magnetic filtered plasma deposition and implantation technique

CERN Document Server

Zhang Hui Xing; Wu Xian Ying

2002-01-01

A high dense metal plasma can be produced by using cathodic vacuum arc discharge technique. The microparticles emitted from the cathode in the metal plasma can be removed when the metal plasma passes through the magnetic filter. It is a new technique for making high quality, fine and close thin films which have very widespread applications. The authors describe the applications of cathodic vacuum arc technique, and then a filtered plasma deposition and ion implantation system as well as its applications

Fundamentals of a moderate thermocracking-deep deasphalting combined process of Karamay vacuum residue

Energy Technology Data Exchange (ETDEWEB)

Zhiming, X; Tonghua, L.; Suogi, Z.; Renan, W. [University of Petroleum, State Key Laboratory of Heavy Oil Processing, Beijing (China); Lailong, L.; Zhen, L. [Karamay Petrochemical Company, Petrochemical Research Institute, Karamay (China)

2004-07-01

Thermocracking of heavy oil vacuum residue was carried out to determine the optimum conditions for the thermal cracking of Karamay vacuum residue prior to coke formation. The vacuum residue and the cracked residue after distillation were separated using supercritical fluid extraction and fractionation techniques. Sixteen and thirteen fractions and non-extractable end cuts respectively were separated, and their properties, compositions and average structures determined. Solubility parameters of the end cuts were measured, and those of the fractions calculated. The solubility parameter of the end cut of distilled residue was found to have greatly increased. It was determined that when the difference of the end cut and the extractable fractions amounts to 6.37MPa1/2, in the case of Karamay vacuum residue coke will deposit under thermocracking conditions. Based on the results of a series of solvent deep deasphalting experiments, a scheme for vacuum residue thermocracking and deasphalting of the cracked residue was proposed.

Vacuum-assisted delivery

Science.gov (United States)

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

Chromium depletion from stainless steels during vacuum annealing

International Nuclear Information System (INIS)

Smith, A.F.; Hales, R.

1977-01-01

During selective chromium oxidation of stainless steels the changes in chromium concentration at the metal surface and in the metal have an important bearing on the overall oxidation performance. It has been proposed that an analogue of chromium behaviour during selective oxidation is obtained from volatilisation of chromium during high temperature vacuum annealing. In the present report the evaporation of chromium from 316 type of steel, vacuum annealed at 1,000 0 C, has been investigated by means of energy dispersive X-ray analysis and by neutron activation analysis. It was established that chromium loss from austenitic stainless steels is rate controlled by interdiffusion in the alloy. As predicted the chromium concentration at the metal surface decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in good agreement with the previously derived model apart from an anomalous region near the surface. Here the higher resolution of the neutron activation technique indicated a zone within approximately 2μm of the surface where the chromium concentration decreased more steeply than expected. (orig.) [de

ATLAS Supplier Award for the ECT Vacuum Vessels

CERN Multimedia

Jenni, P

On 12 February the Netherlands firm Schelde Exotech was awarded the ATLAS Supplier Award for the construction of the two vacuum vessels for the ATLAS End- Cap Toroid (ECT) magnets. ATLAS Supplier Award ceremonies have now become something of a tradition. For the third consecutive year, ATLAS has given best supplier awards for the most exceptional contributors to the construction of the detector. The Netherlands firm Schelde Exotech has just received the award for the construction of the two vacuum vessels for the ECTs. With a diameter of 11 metres and a volume of 550 cubic metres, the ECT vacuum vessels are obviously impressive in scale. They consist of large aluminium plates and a stainless steel central bore tube. In order to obtain the required undulations, the firm had to develop a special assembly and welding technique. Despite the chambers' imposing size, a very high degree of precision has been achieved in their geometry. Moreover, the chambers, which were delivered in July 2002 to CERN, were built i...

Centrifugal vacuum casting for fuel cladding tube blanks

International Nuclear Information System (INIS)

Zelenskii, V.F.; Neklyudov, I.M.; Chernyi, B.P.; Zeidlits, M.P.; Vanzha, A.F.; Rubashko, V.G.; Ryabchikov, L.N.; Smirnov, Y.K.; Bespalova, V.R.; Mashkarova, V.T.; Rybal'chenko, N.D.

1990-01-01

An advanced technique for making tube blanks with an acceptable level of nonmetallic inclusions is vacuum induction melting combined with centrifugal casting, as the latter gives a cylindrical casting having an axial hole, while the cast metal has elevated density and contains fewer nonmetallic inclusions than does the metal cast in a stationary mold. The reduction in the nonmetallic inclusions occurs because of increased rates of floating up in the rotating mold on account of the centrifugal force and the rejection to the inner surface. One can choose the parameters such as the pouring speed, rotational speed, mold cooling, and liquid-metal temperature and can introduce a deoxidizer to remove the nonmetallic inclusions or reduce the grain size of them and produce an appropriate cast structure and obtain a metal whose quality is the same as that on vacuum induction melting with secondary arc remelting. For these purposes, the authors have developed centrifugal-casting machines for use under vacuum or in inert gases with horizontal and vertical mold rotation axes

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

Science.gov (United States)

Zhan, Lu; Xu, Zhenming

2014-12-16

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

Straw detector: 1 - Vacuum: 0

CERN Multimedia

Katarina Anthony

2012-01-01

The NA62 straw tracker is using pioneering CERN technology to measure charged particles from very rare kaon decays. For the first time, a large straw tracker with a 4.4 m2 coverage will be placed directly into an experiment’s vacuum tank, allowing physicists to measure the direction and momentum of charged particles with extreme precision. NA62 measurements using this technique will help physicists take a clear look at the kaon decay rate, which might be influenced by particles and processes that are not included in the Standard Model.   Straw ends are glued to an aluminium frame, a crucial step in the assembly of a module. The ends are then visually inspected before a leak test is performed.  “Although straw detectors have been around since the 1980s, what makes the NA62 straw trackers different is that they can work under vacuum,” explains Hans Danielsson from the PH-DT group leading the NA62 straw project. Straw detectors are basically small drift cha...

Field installed brazed thermocouple feedthroughs for high vacuum experiments

International Nuclear Information System (INIS)

Anderson, P.; Messick, C.

1983-01-01

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

Expansion of laser-produced plasmas into vacuum and ambient gases

International Nuclear Information System (INIS)

Williams, T.

2001-01-01

Presented in this thesis are observations recorded using optical absorption spectroscopy, laser induced fluorescence imaging and Langmuir probe techniques for a low temperature laser-produced plasma. The plasma was generated using a KrF (248 nm, 30ns) excimer laser system focused onto a solid target surface (Ti, Mg) housed within a vacuum chamber. Plasma studies were made within vacuum (x10 -5 mTorr) and low pressure ( 2 and Ar ambient gas environments. Experimental results from a volumetric integration technique for plasma species number densities are used to yield total plume content for a laser-produced plasma in vacuum. This was used to determine the threshold power density for titanium neutral species formation. Temporally resolved electron number densities were determined using a Langmuir probe technique, for a titanium plasma generated under 532 nm and 248 nm ablation, for similar power densities and spot geometries. In this case the ablation thresholds for titanium are determined in terms of average power density and peak power density. Plume opacity problems which limit OAS and LIF diagnostic techniques are minimised using novel ablations configurations. Both techniques used, the 'composite target' and the 'plasma-jet' configurations, rely on reducing the optical thickness of the plume. The plasma-jets produced were allowed to interact with an ambient argon background and the ion/neutral ratio of the plasma-jet determined. Laser-produced plasma interactions with a d.c. biased copper mesh ∼15 mm in front of the target surface are observed. Self-emission studies of plume interactions with the mesh are monitored for positive and negative biases. Also ground-state neutral and ion interactions with the mesh are observed using OAS and LIF techniques to study individual species effects. A simple model was used to predict the perturbations to charged species distributions resulting from positive and negative applied potentials, but more complex interaction

Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

Directory of Open Access Journals (Sweden)

Chin-Guo Kuo

2016-03-01

Full Text Available In this investigation, anodic aluminum oxide (AAO with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

Vacuum infusion manufacturing and experimental characterization of Kevlar/epoxy composites

International Nuclear Information System (INIS)

Ricciardi, M. R.; Giordano, M.; Antonucci, V.; Langella, A.; Nele, L.

2014-01-01

Epoxy/Kevlar composites have been manufactured by conventional Vacuum Infusion process and the Pulse Infusion technique. Pulse Infusion allows to control the pressure of the vacuum bag on the dry fiber reinforcement by using a proper designed pressure distributor that induces a pulsed transverse action and promotes the through thickness resin flow. The realized composite panel have been mechanically characterized by performing tensile and short beam shear tests according with the ASTM D3039 and ASTM D2344/D 2344M standard respectively in order to investigate the effect of Pulse Infusion on the tensile strength and ILSS

Vacuum infusion manufacturing and experimental characterization of Kevlar/epoxy composites

Science.gov (United States)

Ricciardi, M. R.; Giordano, M.; Langella, A.; Nele, L.; Antonucci, V.

2014-05-01

Epoxy/Kevlar composites have been manufactured by conventional Vacuum Infusion process and the Pulse Infusion technique. Pulse Infusion allows to control the pressure of the vacuum bag on the dry fiber reinforcement by using a proper designed pressure distributor that induces a pulsed transverse action and promotes the through thickness resin flow. The realized composite panel have been mechanically characterized by performing tensile and short beam shear tests according with the ASTM D3039 and ASTM D2344/D 2344M standard respectively in order to investigate the effect of Pulse Infusion on the tensile strength and ILSS.

An examination of the thermodynamics of fusion, vaporization, and sublimation of (R,S)- and (R)-flurbiprofen by correlation gas chromatography.

Science.gov (United States)

Umnahanant, Patamaporn; Hasty, Darrell; Chickos, James

2012-06-01

The vaporization, fusion, and sublimation enthalpies of (R,S)- and (R)-flurbiprofen at T = 298.15 K are reported and compared with literature values when available. Correlation gas chromatography experiments were first performed to identify appropriate standards that could be used for materials containing a single fluorine substituent. Subsequent correlations resulted in a vaporization enthalpy for (R,S)-flurbiprofen and (R)-flurbiprofen, ΔH(vap) (298.15 K), of (127.5 ± 5.5) and (127.4 ± 4.7) kJ mol, respectively. Fusion enthalpies, ΔH(fus) (387 K), of (28.2 ± and, ΔH(fus) (381 K), (22.8 ± kJ mol(-1) were also measured by differential scanning calorimetry for the racemic and chiral forms of flurbiprofen. Adjusted to T = 298.15 K and combined with the vaporization enthalpy resulted in sublimation enthalpies, ΔH(sub) (298.15 K), of (155.6 ± 5.8) and (145.1 ± 5.7) kJ mol(-1) for (R,S)- and (R)-flurbiprofen, respectively. The fusion enthalpy measured for the racemic form was in excellent agreement with the literature value, while the sublimation enthalpy varies substantially from previous work. Two weak solid-solid phase transitions were also observed for (R)-flurbiprofen at T = 353.9 K (0.30 ± 0.1) and 363.2 K (0.21 ± 0.03) kJ · mol(-1). Copyright © 2012 Wiley Periodicals, Inc.

A simplification of the deuterium oxide dilution technique using FT-IR analysis of plasma, for estimating piglet milk intake

International Nuclear Information System (INIS)

Glencross, B.D.; Tuckey, R.C.; Hartmann, P.E.; Mullan, B.P.

1997-01-01

Previous studies estimating milk intake using deuterium oxide (D 2 O) as a tracer have required sublimation of the sample fluid (usually plasma) to remove solids and retrieve total water. This procedure has been simplified by directly measuring the D 2 O content of plasma with a Fourier transform-infrared (FT-IR) spectrometer, removing the requirement for sample sublimation. Comparisons of samples that were split and then analysed as water of sublimation and as total plasma were performed. It was found that the direct analysis of the plasma could be achieved without a loss in fidelity of the results (sublimated v. plasma, r 2 = 0.976; n = 26). Linearity of assay standards was very high (r 2 > 0.997). The modified technique was used to determine the milk intake by piglets from litters of 7 sows during established lactation (Days 10-15). Water turnover (WTO) was shown to be the primary point by which differences in the piglet milk intakes were influenced. Differences in the milk composition had minimal effect on the milk intake determinations. Milk intake by each piglet was shown to be strongly correlated to piglet growth (r 2 = 0.59, P 2 = 0.84, P < 0.01). Copyright (1997) CSIRO Australia

Polarized vacuum ultraviolet and X-radiation

International Nuclear Information System (INIS)

Samson, J.A.R.

1978-01-01

The most intense source of polarized vacuum UV and X-radiation is synchrotron radiation, which exhibits a degree of partially polarized light between about 80-100%. However, the radiation transmitted by vacuum UV monochromators can also be highly polarized. The Seya-Namioka type of monochromator can produce partially polarized radiation between 50-80%. For certain experiments it is necessary to know the degree of polarisation of the radiation being used. Also, when synchrotron radiation and a monochromator are combined the polarization characteristic of both should be known in order to make full use of these polarization properties. The polarizing effect on monochromators (i.e. diffraction gratings) have been measured at the Seya angle and at grazing angles for various spectral orders. The author presents the first experimental evidence that the reciprocity law holds for polarization by reflection where the angle of incidence and diffraction are unequal. These results are reviewed along with the techniques for measuring the degree of polarization. (Auth.)

11-gauge vacuum assisted directional biopsy of breast calcifications, using upright stereotactic guidance

International Nuclear Information System (INIS)

Nisbet, A.P.; Borthwick-Clarke, A.; Scott, N.

2000-01-01

To assess the use of a prototype vacuum assisted biopsy device on a standard upright mammography unit, using a slightly modified digital stereotactic add-on component. A group comprised of 42 sequential patients, who had been recalled from an asymptomatic mammographic screening programme, were studied. All 42 were recalled for assessment of small clusters of microcalcification, graded as indeterminate. Group 1 (21 patients) were biopsied using 14-gauge automated large core needle biopsy. Group 2 (21 patients) were biopsied using 11-gauge vacuum assisted biopsy. Both groups had mammographic guidance on the same upright mammographic unit (Siemens 3000), with Opdima Digital Stereotactic add-on. A total of 86% of specimen radiographs in Group 2 patients (vacuum assisted biopsy) showed successful sampling of the calcifications, compared to 62% of Group 1 patients (14-gauge automated large core biopsies). This study shows that vacuum assisted biopsy is possible using upright stereotactic mammography units. The technique shows promise as a biopsy tool, offering larger cores compared to 14-gauge automated large core biopsy, while requiring less space and lower purchase price compared to dedicated prone biopsy tables. The technique also offers access to biopsy in patients with posterior lesions and for patients who cannot tolerate prone positioning

Sublimation-assisted graphene transfer technique based on small polyaromatic hydrocarbons

Science.gov (United States)

Chen, Mingguang; Stekovic, Dejan; Li, Wangxiang; Arkook, Bassim; Haddon, Robert C.; Bekyarova, Elena

2017-06-01

Advances in the chemical vapor deposition (CVD) growth of graphene have made this material a very attractive candidate for a number of applications including transparent conductors, electronics, optoeletronics, biomedical devices and energy storage. The CVD method requires transfer of graphene on a desired substrate and this is most commonly accomplished with polymers. The removal of polymer carriers is achieved with organic solvents or thermal treatment which makes this approach inappropriate for application to plastic thin films such as polyethylene terephthalate substrates. An ultraclean graphene transfer method under mild conditions is highly desired. In this article, we report a naphthalene-assisted graphene transfer technique which provides a reliable route to residue-free transfer of graphene to both hard and flexible substrates. The quality of the transferred graphene was characterized with atomic force microscopy, scanning electron microscopy, and Raman spectroscopy. Field effect transistors, based on the naphthalene-transfered graphene, were fabricated and characterized. This work has the potential to broaden the applications of CVD graphene in fields where ultraclean graphene and mild graphene transfer conditions are required.

A system for the study of molecular contamination. [experimental vacuum chambers

Science.gov (United States)

Dillow, C. F.; Allen, T. H.; Linford, R. M. F.; Richmond, R. G.

1975-01-01

An experimental vacuum chambers was designed and fabricated to provide a wide range of experimental capability. This work chamber assembly (WCA) was conceived to establish the proof-of-principle of various techniques for studying the kinetics of contaminants and their effects. It incorporates the capability for depositing both optical and contaminant films on temperature-controlled samples, and for in-situ measurements of the vacuum ultraviolet reflectance. Ellipsometer optics are mounted on the chamber for film thickness determinations, and other features include access ports for radiation sources and instrumentation.

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

Directory of Open Access Journals (Sweden)

Angel Delgado

2016-01-01

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

Methods of conveying fluids and methods of sublimating solid particles

Science.gov (United States)

Turner, Terry D; Wilding, Bruce M

2013-10-01

A heat exchanger and associated methods for sublimating solid particles therein, for conveying fluids therethrough, or both. The heat exchanger includes a chamber and a porous member having a porous wall having pores in communication with the chamber and with an interior of the porous member. A first fluid is conveyed into the porous member while a second fluid is conveyed into the porous member through the porous wall. The second fluid may form a positive flow boundary layer along the porous wall to reduce or eliminate substantial contact between the first fluid and the interior of the porous wall. The combined first and second fluids are conveyed out of the porous member. Additionally, the first fluid and the second fluid may each be conveyed into the porous member at different temperatures and may exit the porous member at substantially the same temperature.

Vacuum Delivery in Jos University Teaching Hospital, Jos, Nigeria ...

African Journals Online (AJOL)

Obstetric practice continues to change, particularly assisted vaginal delivery. Vacuum delivery is a mode of delivery technique in Jos University Teaching Hospital (JUTH) in the maternity unit. The objective of the study was to determine the rate of ventouse delivery, its indications, and maternal and fetal morbidity in our ...

Investigation of Non-Vacuum Deposition Techniques in Fabrication of Chalcogenide-Based Solar Cell Absorbers

KAUST Repository

Alsaggaf, Ahmed

2015-01-01

simulating R2R process design at speeds up to 1.05 m/min. The research clarified morphological and compositional impacts of Nd:YAG laser heat-treatment on Cu(In,Ga)Se2 absorber layer to simplify the annealing step in non-vacuum environment compatible to R2R

Modern vacuum physics

CERN Document Server

Chambers, Austin

2005-01-01

Modern Vacuum Physics presents the principles and practices of vacuum science and technology along with a number of applications in research and industrial production. The first half of the book builds a foundation in gases and vapors under rarefied conditions, The second half presents examples of the analysis of representative systems and describes some of the exciting developments in which vacuum plays an important role. The final chapter addresses practical matters, such as materials, components, and leak detection. Throughout the book, the author''s explanations are presented in terms of first principles and basic physics, augmented by illustrative worked examples and numerous figures.

Gravitation and vacuum field

International Nuclear Information System (INIS)

Tevikyan, R.V.

1986-01-01

This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E → ∞. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory

Surge-damping vacuum valve

International Nuclear Information System (INIS)

Bullock, J.C.; Kelley, B.E.

1977-01-01

A valve for damping out flow surges in a vacuum system is described. The surge-damping mechanism consists of a slotted, spring-loaded disk adjacent to the valve's vacuum port (the flow passage to the vacuum roughing pump). Under flow surge conditions, the differential pressure forces the disk into a sealing engagement with the vacuum port, thereby restricting the gas flow path to narrow slots in the disk's periphery. The increased flow damps out the flow surge. When pressure is equalized on both sides of the valve, the spring load moves the disk away from the port to restore full flow conductance through the valve

Homogeneity of Gd-based garnet transparent ceramic scintillators for gamma spectroscopy

Science.gov (United States)

Seeley, Z. M.; Cherepy, N. J.; Payne, S. A.

2013-09-01

Transparent polycrystalline ceramic scintillators based on the composition Gd1.49Y1.49Ce0.02Ga2.2Al2.8O12 are being developed for gamma spectroscopy detectors. Scintillator light yield and energy resolution depend on the details of various processing steps, including powder calcination, green body formation, and sintering atmosphere. We have found that gallium sublimation during vacuum sintering creates compositional gradients in the ceramic and can degrade the energy resolution. While sintering in oxygen produces ceramics with uniform composition and little afterglow, light yields are reduced, compared to vacuum sintering. By controlling the atmosphere during the various process steps, we were able to minimize the gallium sublimation, resulting in a more homogeneous composition and improved gamma spectroscopy performance.

Comparison of vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification systems.

Science.gov (United States)

Han, Young Keun; Miller, Kevin M

2009-08-01

To compare vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification machines. Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA. The vacuum rise time under normal and enhanced aspiration modes, vacuum limit accuracy, and occlusion break surge of the Infiniti Vision System, Stellaris Vision Enhancement System, and WhiteStar Signature Phacoemulsification System were tested. Vacuum rise time and limit accuracy were measured at limit settings of 400 mm Hg and 600 mm Hg. Surge area was recorded at vacuum limit settings of 200 mm Hg, 300 mm Hg, 400 mm Hg, and 500 mm Hg. The Infiniti had the fastest vacuum rise times under normal and enhanced aspiration modes. At 4 seconds, the vacuum limit accuracy was greatest with the Infiniti at the 400 mm Hg limit and the Signature at the 600 mm Hg limit. The Stellaris did not reach either vacuum target. The Infiniti performed better than the other 2 machines during testing of occlusion break surge at all vacuum limit settings above 200 mm Hg. Under controlled laboratory test conditions, the Infiniti had the fastest vacuum rise time, greatest vacuum limit accuracy at 400 mm Hg, and least occlusion break surge. These results can be explained by the lower compliance of the Infiniti system.

Electrospray ionization deposition of BSA under vacuum conditions

Science.gov (United States)

Hecker, Dominic; Gloess, Daniel; Frach, Peter; Gerlach, Gerald

2015-05-01

Vacuum deposition techniques like thermal evaporation and CVD with their precise layer control and high layer purity often cannot be applied for the deposition of chemical or biological molecules. The molecules are usually decomposed by heat. To overcome this problem, the Electrospray ionization (ESI) process known from mass spectroscopy is employed to transfer molecules into vacuum and to deposit them on a substrate. In this work, a homemade ESI tool was used to deposit BSA (Bovine serum albumin) layers with high deposition rates. Solutions with different concentrations of BSA were prepared using a methanol:water (MeOH:H2O) mixture (1:1) as solvent. The influence of the substrate distance on the deposition rate and on the transmission current was analyzed. Furthermore, the layer thickness distribution and layer adhesion were investigated.

Vacuum type D initial data

Science.gov (United States)

García-Parrado Gómez-Lobo, Alfonso

2016-09-01

A vacuum type D initial data set is a vacuum initial data set of the Einstein field equations whose data development contains a region where the space–time is of Petrov type D. In this paper we give a systematic characterisation of a vacuum type D initial data set. By systematic we mean that the only quantities involved are those appearing in the vacuum constraints, namely the first fundamental form (Riemannian metric) and the second fundamental form. Our characterisation is a set of conditions consisting of the vacuum constraints and some additional differential equations for the first and second fundamental forms These conditions can be regarded as a system of partial differential equations on a Riemannian manifold and the solutions of the system contain all possible regular vacuum type D initial data sets. As an application we particularise our conditions for the case of vacuum data whose data development is a subset of the Kerr solution. This has applications in the formulation of the nonlinear stability problem of the Kerr black hole.

Development and Testing of an ISRU Soil Mechanics Vacuum Test Facility

Science.gov (United States)

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.

Vacuum pumping concepts for ETF

International Nuclear Information System (INIS)

Homeyer, W.G.

1980-09-01

The Engineering Test Facility (ETF) poses unique vacuum pumping requirements due to its large size and long burn characteristics. These requirements include torus vacuum pumping initially and between burns and pumping of neutralized gas from divertor collector chambers. It was found that the requirements could be met by compound cryopumps in which molecular sieve 5A is used as the cryosorbent. The pumps, ducts, and vacuum valves required are large but fit with other ETF components and do not require major advances in vacuum pumping technology. Several additional design, analytical, and experimental studies were identified as needed to optimize designs and provide better design definition for the ETF vacuum pumping systems

Status of the ITER vacuum vessel construction

Energy Technology Data Exchange (ETDEWEB)

Choi, C.H.; Sborchia, C.; Ioki, K.; Giraud, B.; Utin, Yu.; Sa, J.W. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Wang, X., E-mail: xiaoyuwww@gmail.com [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Teissier, P.; Martinez, J.M.; Le Barbier, R.; Jun, C.; Dani, S.; Barabash, V.; Vertongen, P.; Alekseev, A. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Jucker, P.; Bayon, A. [F4E, c/ Josep Pla, n. 2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Pathak, H.; Raval, J. [ITER-India, IPR, A-29, Electronics Estate, GIDC, Sector-25, Gandhinagar 382025 (India); Ahn, H.J. [ITER Korea, National Fusion Research Institute, Daejeon (Korea, Republic of); and others

2014-10-15

Highlights: • Final design of the ITER vacuum vessel (VV). • Procurement of the ITER VV. • Manufacturing results of real scale mock-ups. • Manufacturing status of the VV in domestic agencies. - Abstract: The ITER vacuum vessel (VV) is under manufacturing by four domestic agencies after completion of engineering designs that have been approved by the Agreed Notified Body (ANB). Manufacturing designs of the VV have been being completed, component by component, by accommodating requirements of the RCC-MR 2007 edition. Manufacturing of the VV first sector has been started in February 2012 in Korea and in-wall shielding in May 2013 in India. EU will start manufacturing of its first sector from September 2013 and Russia the upper port by the end of 2013. All DAs have manufactured several mock-ups including real-size ones to justify/qualify and establish manufacturing techniques and procedures.

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

International Nuclear Information System (INIS)

Xiang Qianfei; Ma Weixing; Zhou Lijuan; Jiang Weizhou

2014-01-01

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

Development of remote welding equipment and techniques for the TFTR vacuum vessel

International Nuclear Information System (INIS)

Masson, L.S.; Watts, K.D.; Larson, R.A.; Aldrich, W.C.

1980-01-01

In the event that the TFTR vacuum vessel is damaged or one of the toroidal field coils fails after the system has become substantially activated, it is necessary to remotely remove and replace the damaged section of the vessel using remote handling procedures. This paper describes a welding system developed through the final design stage to perform the remote welding necessary during the replacement operation. Information is presented describing the vessel configuration, the replacement sequence, the welding system requirements, welder configuration, supporting systems, the weld development program and future development requirements

Shiva and Argus target diagnostics vacuum systems

International Nuclear Information System (INIS)

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

1978-09-01

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

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

CERN Document Server

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

2014-01-01

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

All-metal vacuum chamber for the ZT-40 experiment

International Nuclear Information System (INIS)

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

1981-10-01

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

The symmetries of the vacuum

International Nuclear Information System (INIS)

Fleming, H.

1985-01-01

The vacuum equation of state required by cosmological inflation is taken seriously as a general property of the cosmological vacuum. This correctly restricts the class of theories which admit inflation. A model of such a vacuum is presented that leads naturally to the cosmological principle. (Author) [pt

Structural characterization of asphaltenes from vacuum residue distillation

International Nuclear Information System (INIS)

Silva, Ronaldo C.; Seidl, Peter R.; Menezes, Sonia M.C. de; Teixeira, Marco A.G.

2001-01-01

The aim of this work was to do structural characterization of asphaltenes from different vacuum residues distillation. Several average molecular parameters using some analytical techniques were obtained and these techniques were: nuclear magnetic resonance ( 1 H and 13 C NMR), elemental analysis (C,H,N,O and S content), Fourier transform infrared (FT-IR), vapor pressure osmometry and gel permeation chromatography. Particularly from NMR, some important molecular parameters were obtained, such as aromatic carbon fraction, aliphatic carbons fraction, alkyl substituted aromatic carbons, unsubstituted aromatic carbons, etc. Molecular modeling will be employed to build the structure of asphaltenes using the experimental data. (author)

Regulating vacuum pump speed with feedback control

International Nuclear Information System (INIS)

Ludington, D.C.; Aneshansley, D.J.; Pellerin, R.; Guo, F.

1992-01-01

Considerable energy is wasted by the vacuum pump/motor on dairy farms. The output capacity (m 3 /min or cfm) of the vacuum pump always exceeds the capacity needed to milk cows and wash pipelines. Vacuum pumps run at full speed and load regardless of actual need for air. Excess air is admitted through a controller. Energy can be saved from electrical demand reduced by regulating vacuum pump speed according to air based on air usage. An adjustable speed drive (ASD) on the motor and controlled based upon air usage, can reduce the energy used by the vacuum pump. However, the ASD unit tested could not maintain vacuum levels within generally accepted guidelines when air usage changed. Adding a high vacuum reserve and a dual vacuum controller between the vacuum pump and the milking pipeline brought vacuum stability within guidelines. The ASD/dual vacuum system can reduce energy consumption and demand by at least 50 percent during milking and provide better vacuum stability than conventional systems. Tests were not run during washing cycles. Using 1990 costs and only the energy saved during milking, the simple payback on investment in new equipment for a 5 hp motor, speed controller and vacuum regulator would be about 5 years

The Source of the Quantum Vacuum

Directory of Open Access Journals (Sweden)

Daywitt W. C.

2009-01-01

Full Text Available The quantum vacuum consists of virtual particles randomly appearing and disappearing in free space. Ordinarily the wavenumber (or frequency spectrum of the zero-point fields for these virtual particles is assumed to be unbounded. The unbounded nature of the spectrum leads in turn to an infinite energy density for the quantum vacuum and an infinite renormalization mass for the free particle. This paper argues that there is a more fundamental vacuum state, the Planck vacuum, from which the quantum vacuum emerges and that the “graininess” of this more fundamental vacuum state truncates the wavenumber spectrum and leads to a finite energy density and a finite renormalization mass.

The Source of the Quantum Vacuum

Directory of Open Access Journals (Sweden)

Daywitt W. C.

2009-01-01

Full Text Available The quantum vacuum consists of virtual particles randomly appearing and disappearing in free space. Ordinarily the wavenumber (or frequency spectrum of the zero-point fields for these virtual particles is assumed to be unbounded. The unbounded nature of the spectrum leads in turn to an infinite energy density for the quantum vacuum and an infinite renormalization mass for the free particle. This paper argues that there is a more fundamental vacuum state, the Planck vacuum, from which the quantum vacuum emerges and that the "graininess" of this more fundamental vacuum state truncates the wavenumber spectrum and leads to a finite energy density and a finite renormalization mass.

Thick epitaxial CdTe films grown by close space sublimation on Ge substrates

Energy Technology Data Exchange (ETDEWEB)

Jiang, Q; Haliday, D P; Tanner, B K; Brinkman, A W [Department of Physics, University of Durham. Science Site, Durham, DH1 3LE (United Kingdom); Cantwell, B J; Mullins, J T; Basu, A [Durham Scientific Crystals Ltd., NetPark, Thomas Wright Way, Sedgefield, County Durham, TS21 3FD (United Kingdom)], E-mail: Q.Z.Jiang@durham.ac.uk

2009-01-07

This paper reports, for the first time, the successful growth of 200 {mu}m thick CdTe films on mis-oriented Ge(1 0 0) substrates by a cost-effective optimized close space sublimation method. It is found that, as the thickness increases to a few hundred micrometres, subgrains are formed probably as a result of the large density of dislocations and strain within the initial interfacial layers. The films are of high quality (x-ray rocking curve width {approx}100 arcsec) and high resistance ({approx}10{sup 9} {omega} cm), and are thus candidates for x-ray and {gamma}-ray detectors. (fast track communication)

Scroll vacuum pump

Energy Technology Data Exchange (ETDEWEB)

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

1988-02-25

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

Cosmology with decaying vacuum energy

International Nuclear Information System (INIS)

Freese, K.; Adams, F.; Frieman, J.; Mottola, E.

1987-09-01

Motivated by recent attempts to solve the cosmological constant problem, we examine the observational consequences of a vacuum energy density which decays in time. For all times later than t ∼ 1 sec, the ratio of the vacuum to the total energy density of the universe must be small. Although the vacuum cannot provide the ''missing mass'' required to close the universe today, its presence earlier in the history of the universe could have important consequences. We discuss restrictions on the vacuum energy arising from primordial nucleosynthesis, the microwave and gamma ray background spectra, and galaxy formation. A small vacuum component at the era of nucleosynthesis, 0.01 5, but in some cases would severely distort the microwave spectrum. 9 refs., 3 figs

Beam vacuum system of Brookhaven's muon storage ring

International Nuclear Information System (INIS)

Hseuth, H.C.; Snydstrup, L.; Mapes, M.

1995-01-01

A storage ring with a circumference of 45 m is being built at Brookhaven to measure the g-2 value of the muons to an accuracy of 0.35 ppm.. The beam vacuum system of the storage ring will operate at 10 -7 Torr and has to be completely non-magnetic. It consists of twelve sector chambers. The chambers are constructed of aluminum and are approximately 3.5 m in length with a rectangular cross-section of 16.5 cm high by 45 cm at the widest point. The design features, fabrication techniques and cleaning methods for these chambers are described. The beam vacuum system will be pumped by forty eight non-magnetic distributed ion pumps with a total pumping speed of over 2000 ell/sec. Monte Carlo simulations of the pressure distribution in the muon storage region are presented

Sludge derived fuel technique of sewage sludge by oil vacuum evaporation drying

International Nuclear Information System (INIS)

Kim, Seokhwan; Lim, Byungran; Lee, Sookoo

2010-01-01

Sewage sludge contains high content of organic materials and its water content is also very high about 80% even after filtration process. Landfill as a sludge treatment methods can cause odor problem and leachate production which can derive the secondary contamination of soil and groundwater. The ocean dumping will be prohibited according to the London Convention and domestic stringent environmental regulation. Based on domestic agenda on organic sewage sludge treatment, the ocean disposal will be prohibited from 2012, thus alternative methods are demanded. Sludge derived fuel (SDF) technology can alleviate the emission of greenhouse gas and recover energy from sludge. For proper treatment and SDF production from sludge, the vacuum evaporation and immersion frying technology was adopted in this research. This technology dries moisture in sludge after mixing with oil such as Bunker C oil, waste oil or waste food oil etc. Mixing sludge and oil secures liquidity of organic sludge to facilitate handling throughout the drying process. The boiling temperature could be maintained low through vacuum condition in whole evaporation process. This study was performed to find the optimum operating temperature and pressure, the mixing ratio of sludge and oil. Finally, we could obtained SDF which moisture content was less than 5%, its heating value was over 4,500 kcal/ kg sludge. This heating value could satisfy the Korean Fuel Standard for the Recycle Products. Assessed from the perspective of energy balance and economic evaluation, this sludge drying system could be widely used for the effective sludge treatment and the production of SDF. (author)

Approximated calculation of the vacuum wave function and vacuum energy of the LGT with RPA method

International Nuclear Information System (INIS)

Hui Ping

2004-01-01

The coupled cluster method is improved with the random phase approximation (RPA) to calculate vacuum wave function and vacuum energy of 2 + 1 - D SU(2) lattice gauge theory. In this calculating, the trial wave function composes of single-hollow graphs. The calculated results of vacuum wave functions show very good scaling behaviors at weak coupling region l/g 2 >1.2 from the third order to the sixth order, and the vacuum energy obtained with RPA method is lower than the vacuum energy obtained without RPA method, which means that this method is a more efficient one

Vacuum structure as seen by overlap fermions

International Nuclear Information System (INIS)

Ilgenfritz, E.M.

2006-11-01

Three complementary views on the QCD vacuum structure, all based on eigenmodes of the overlap operator, are reported in their interrelation: (i) spectral density, localization and chiral properties of the modes, (ii) the possibility of filtering the field strength with the aim to detect selfdual and antiselfdual domains and (iii) the various faces of the topological charge density, with and without a cutoff λ cut = O(Λ QCD ). The techniques are tested on quenched SU(3) configurations. (orig.)

Cold Vacuum Drying (CVD) Facility Vacuum Purge System Chilled Water System Design Description. System 47-4

International Nuclear Information System (INIS)

IRWIN, J.J.

2000-01-01

This system design description (SDD) addresses the Vacuum Purge System Chilled Water (VPSCHW) system. The discussion that follows is limited to the VPSCHW system and its interfaces with associated systems. The reader's attention is directed to Drawings H-1-82162, Cold Vacuum Drying Facility Process Equipment Skid PandID Vacuum System, and H-1-82224, Cold Vacuum Drying Facility Mechanical Utilities Process Chilled Water PandID. Figure 1-1 shows the location and equipment arrangement for the VPSCHW system. The VPSCHW system provides chilled water to the Vacuum Purge System (VPS). The chilled water provides the ability to condense water from the multi-canister overpack (MCO) outlet gases during the MCO vacuum and purge cycles. By condensing water from the MCO purge gas, the VPS can assist in drying the contents of the MCO

Vacuum-assisted closure therapy in the management of lung abscess.

Science.gov (United States)

Sziklavari, Zsolt; Ried, Michael; Hofmann, Hans-Stefan

2014-09-06

Despite significant advances in the treatment of thoracic infections, complex lung abscess remains a problem in modern thoracic surgery. We describe the novel application of vacuum-assisted closure for the treatment of a lung abscess. The technical details and preliminary results are reported. After the initial failed conservative treatment of an abscess, minimally invasive surgical intervention was performed with vacuum-assisted closure. The vacuum sponges were inserted in the abscess cavity at the most proximal point to the pleural surface. The intercostal space of the chest wall above the entering place was secured by a soft tissue retractor. The level of suction was initially set to 100 mm Hg, with a maximum suction of 125 mm Hg. The sponge was changed once on the 3rd postoperative day. The abscess cavity was rapidly cleaned and decreased in size. The mini-thoracotomy could be closed on the 9th postoperative day. Closure of the cavity was simple, without any short- or long-term treatment failure. This technique reduced the trauma associated with the procedure. The patient was discharged on the 11th postoperative day. Vacuum-assisted closure systems should be considered for widespread use as an alternative option for the treatment of complicated pulmonary abscess in elderly, debilitated, immunocompromised patients after failed conservative treatment.

Vacuum science, technology, and applications

CERN Document Server

Naik, Pramod K

2018-01-01

Vacuum plays an important role in science and technology. The study of interaction of charged particles, neutrals and radiation with each other and with solid surfaces requires a vacuum environment for reliable investigations. Vacuum has contributed immensely to advancements made in nuclear science, space, metallurgy, electrical/electronic technology, chemical engineering, transportation, robotics and many other fields. This book is intended to assist students, scientists, technicians and engineers to understand the basics of vacuum science and technology for application in their projects. The fundamental theories, concepts, devices, applications, and key inventions are discussed.

Vacuum leak detector and method

Science.gov (United States)

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.

In situ measurement of ceramic vacuum chamber conductive coating quality

International Nuclear Information System (INIS)

Doose, C.; Harkay, K.; Kim, S.; Milton, S.

1997-01-01

A method for measuring the relative surface resistivity and quality of conductive coatings on ceramic vacuum chambers was developed. This method is unique in that it allows one to test the coating even after the ceramic chamber is installed in the accelerator and under vacuum; furthermore, the measurement provides a localized surface reading of the coating conductance. The method uses a magnetic probe is calibrated using the measured DC end-to-end resistance of the tube under test and by comparison to a high quality test surface. The measurement method has also been verified by comparison to high frequency impedance measurements. A detailed description, results, and sensitivity of the technique are given here

Vapor pressures and standard molar enthalpies, entropies and Gibbs energies of sublimation of two hexachloro herbicides using a TG unit

International Nuclear Information System (INIS)

Vecchio, Stefano

2010-01-01

The vapor pressures above the solid hexachlorobenzene (HCB) and above both the solid and liquid 1,2,3,4,5,6-hexachlorocyclohexane (lindane) were determined in the ranges 332-450 K and 347-429 K, respectively, by measuring the mass loss rates recorded by thermogravimetry under both isothermal and nonisothermal conditions. The results obtained were compared with those taken from literature. From the temperature dependence of vapor pressure derived by the experimental thermogravimetry data the molar enthalpies of sublimation Δ cr g H m o ( ) were selected for HCB and lindane as well as the molar enthalpy of vaporization Δ l g H m o ( ) for lindane only, at the middle of the respective temperature intervals. The melting temperatures and the molar enthalpies of fusion Δ cr l H m o (T fus ) of lindane were measured by differential scanning calorimetry. Finally, the standard molar enthalpies of sublimation Δ cr g H m o (298.15 K) were obtained for both chlorinated compounds at the reference temperature of 298.15 K using the Δ cr g H m o ( ), Δ l g H m o ( ) and Δ cr l H m o (T fus ) values, as well as the heat capacity differences between gas and liquid and the heat capacity differences between gas and solid, Δ l g C p,m o and Δ cr g C p,m o , respectively, both estimated by applying a group additivity procedure. Therefore, the averages of the standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs energies of sublimation at 298.15 K, have been derived.

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

Science.gov (United States)

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

2018-01-31

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

Technical specification for vacuum systems

International Nuclear Information System (INIS)

Khaw, J.

1987-01-01

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

Evaporation under vacuum condition

International Nuclear Information System (INIS)

Mizuta, Satoshi; Shibata, Yuki; Yuki, Kazuhisa; Hashizume, Hidetoshi; Toda, Saburo; Takase, Kazuyuki; Akimoto, Hajime

2000-01-01

In nuclear fusion reactor design, an event of water coolant ingress into its vacuum vessel is now being considered as one of the most probable accidents. In this report, the evaporation under vacuum condition is evaluated by using the evaporation model we have developed. The results show that shock-wave by the evaporation occurs whose behavior strongly depends on the initial conditions of vacuum. And in the case of lower initial pressure and temperature, the surface temp finally becomes higher than other conditions. (author)

Vacuum brazing techniques for irradiation devices at TRIGA research reactor

International Nuclear Information System (INIS)

Savu, M.; Valeca, S. C.; Amzoi, A.

2016-01-01

Metallic thin-walled thermocouples are required for monitoring the temperature value for experiments that are conducted in a nuclear research reactor. The different location wall crossing is made by instrumented passage. Such a passage produced by vacuum brazing using a BNi-7 alloy, represents the proper way to obtain a sealed joint, which can withstand corrosion and high temperatures, having in the same time a small neutron cross section. This paper presents the brazing experiments of K-type thermocouples with stainless steel and Inconel 600 sheath. The sheaths brittleness, hardness changing in joint.s vicinity and structural modification emphasized by metallographic analysis are aspects treated by comparing different samples obtained in brazing laboratory. For finding the correct answer regarding the attenuation of negative effects which are occurring during brazing procedure using Inconel 600 - BNi-7 combination, one can assess both the adopted solution used in designing instrumented passage and thermal regime parameters and its precisely control. (authors)

Gauge field vacuum structure in geometrical aspect

International Nuclear Information System (INIS)

Konopleva, N.P.

2003-01-01

Vacuum conception is one of the main conceptions of quantum field theory. Its meaning in classical field theory is also very profound. In this case the vacuum conception is closely connected with ideas of the space-time geometry. The global and local geometrical space-time conceptions lead to different vacuum definitions and therefore to different ways of physical theory construction. Some aspects of the gauge field vacuum structure are analyzed. It is shown that in the gauge field theory the vacuum Einstein equation solutions describe the relativistic vacuum as common vacuum of all gauge fields and its sources. Instantons (both usual and hyperbolical) are regarded as nongravitating matter, because they have zero energy-momentum tensors and correspond to vacuum Einstein equations

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

Science.gov (United States)

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.

Pulse discharge cleaning of the vacuum vessel of HL-1 tokamak

International Nuclear Information System (INIS)

Li Guodong; Zhu Yukun; Xiao Zhenggui; Sun Shouqi; Ze Mingrui

1986-01-01

The HL-1 Tokamak was test-operated on September 21, 1984. During the period of vacuum conditioning, including 60 hours of baking up to 200 deg C and 7 x 10 4 shots of pulse discharge cleaning, the calculated quantities of carbon and oxygen removed are equivalent to 24 and 6 monolayers, respectively. Then, 124 shots of tokamak discharge were performed with low level plasma parameters. The plasma current and pulse length achieved were 60 kA and 85 ms at the toroidal magnetic field of 15 kG. This paper described the techniques used and the effect on discharge characteristics of bakeout and pulse discharge cleaning of the vacuum vessel

Controlling the net charge on a nanoparticle optically levitated in vacuum

Science.gov (United States)

Frimmer, Martin; Luszcz, Karol; Ferreiro, Sandra; Jain, Vijay; Hebestreit, Erik; Novotny, Lukas

2017-06-01

Optically levitated nanoparticles in vacuum are a promising model system to test physics beyond our current understanding of quantum mechanics. Such experimental tests require extreme control over the dephasing of the levitated particle's motion. If the nanoparticle carries a finite net charge, it experiences a random Coulomb force due to fluctuating electric fields. This dephasing mechanism can be fully excluded by discharging the levitated particle. Here, we present a simple and reliable technique to control the charge on an optically levitated nanoparticle in vacuum. Our method is based on the generation of charges in an electric discharge and does not require additional optics or mechanics close to the optical trap.

Vacuum metastability with black holes

Energy Technology Data Exchange (ETDEWEB)

Burda, Philipp [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute, 31 Caroline Street North,Waterloo, ON, N2L 2Y5 (Canada); Moss, Ian G. annd [School of Mathematics and Statistics, Newcastle University,Newcastle Upon Tyne, NE1 7RU (United Kingdom)

2015-08-24

We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evaporation process. Finally, we comment on the application of these results to vacuum decay seeded by black holes produced in particle collisions.

Vacuum metastability with black holes

International Nuclear Information System (INIS)

Burda, Philipp; Gregory, Ruth; Moss, Ian G. annd

2015-01-01

We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evaporation process. Finally, we comment on the application of these results to vacuum decay seeded by black holes produced in particle collisions.

Vacuum exhaust duct used for thermonuclear device

International Nuclear Information System (INIS)

Tachikawa, Nobuo; Kondo, Mitsuaki; Honda, Tsutomu.

1990-01-01

The present invention concerns a vacuum exhaust duct used for a thermonuclear device. A cylindrical metal liners is lined with a gap to the inside of a vacuum exhaust duct main body. Bellows are connected to both ends of the metal liners and the end of the bellows is welded to the vacuum exhaust duct main body. Futher, a heater is mounted to the metal liner on the side of the vacuum exhaust duct main body, and the metal liner is heated by the heater to conduct baking for the vacuum exhaust duct main body. Accordingly, since there is no requirement for elevating the temperature of the vacuum exhaust duct upon conducting baking, the vacuum exhaust duct scarcely suffers substantial deformation due to heat expansion. Further, there is also no substantial deformation for the bellows disposed between the outer circumference of the vacuum vessel and a portion of a vacuum exhaust duct, so that the durability of the bellows is greatly improved. (I.S.)

Case study of shallow soil mixing and soil vacuum extraction remediation project

International Nuclear Information System (INIS)

Carey, M.J.; Day, S.R.; Pinewski, R.; Schroder, D.

1995-01-01

Shallow Soil Mixing (SSM) and Soil Vacuum Extraction (SVE) are techniques which have been increasingly relied on for the insitu remediation of contaminated soils. The primary applications of SSM have been to mix cement, bentonite, or other reagents to modify properties and thereby remediate contaminated soils or sludges. Soil vacuum extraction has been used at numerous applications for insitu removal of contaminants from soils. At a recent project in southern Ohio, the two technologies were integrated and enhanced to extract volatile organic compounds (VOCs) from soils at a Department of Energy facility. Advantages of the integrated SSM/SVE technology over alternative technologies include a relatively rapid remediation compared to other in-situ techniques at a lower cost, less exposure of waste to the surface environment and elimination of off-site disposal. These advantages led to the selection of the use of both technologies on the project in Southern Ohio. The information presented in this paper is intended to provide Engineers and owners with the level of understanding necessary to apply soil mixing and vacuum extraction technology to a specific site. The most important steps in implementing the technology are site investigation, feasibility estimate, selection of performance criteria, selection of appropriate materials, bench scale testing and construction

Studies on structural analysis related to the design of the JT-60 vacuum vessel

International Nuclear Information System (INIS)

Takatsu, Hideyuki

1987-06-01

Studies on structural analysis of a vacuum vessel of tokamak-type fusion devices are presented. The present studies are proposals for the structural analysis procedures of the tokamak-type fusion devices and are composed of five parts, each of which covers the fundamental area required for the structural analysis and design; stress analysis, dynamic response analysis, fatigue evaluation, buckling analysis and seismic analysis. Special attention is paid to the critical component, bellows and the critical load, electromagnetic forces. A new finite element method modeling technique is proposed for the stress analysis of U-shaped bellows, where the bellows is replaced by an orthotropic plate having the same stiffness as the bellows. The applicability of the present modeling technique is confirmed by verification tests. Dynamic response and fatigue of the vacuum vessel are critical issues of the structural analysis and design of the tokamak-type fusion devices. Detailed dynamic response analyses of the JT-60 vacuum vessel are presented paying special attention to the dynamic behavior of the U-shaped bellows, where the above-mentioned modeling technique of the U-shaped bellows is applied. A fatigue evaluation method of the vacuum vessel under the dynamic electromagnetic forces is proposed, which utilizes the results of the detailed dynamic response analysis. In the present method, fatigue evaluation method for random loads is applied. Torsional fatigue strength of the welded bellows is experimentally evaluated aiming the application to the port of the fusion device and it is shown that the welded bellows reveals elastic buckling and spiral distortion under a small angle of tortion. Two formulae are proposed to evaluate the stress of the welded bellows under the forced angle of tortion. (author)

Optical Search for QED vacuum magnetic birefringence, Axions and photon Regeneration

CERN Multimedia

Pugnat, P; Hryczuk, A; Finger, M; Finger, M; Kral, M

2007-01-01

Since its prediction in 1936 by Euler, Heisenberg and Weisskopf in the earlier development of the Quantum Electrodynamic (QED) theory, the Vacuum Magnetic Birefringence (VMB) is still a challenge for optical metrology techniques. According to QED, the vacuum behaves as an optically active medium in the presence of an external magnetic field. It can be experimentally probed with a linearly polarized laser beam. After propagating through the vacuum submitted to a transverse magnetic field, the polarization of the laser beam will change to elliptical and the parameters of the polarization are directly related to fundamental constants such as the fine structure constant and the electron Compton wavelength. Contributions to the VMB could also arise from the existence of light scalar or pseudo-scalar particles like axions that couple to two photons and this would manifest itself as a sizeable deviation from the initial QED prediction. On one side, the interest in axion search, providing an answer to the strong-CP p...

Automatic electromagnetic valve for previous vacuum

International Nuclear Information System (INIS)

Granados, C. E.; Martin, F.

1959-01-01

A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)

Development of vacuum brazing furnace

International Nuclear Information System (INIS)

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

2005-01-01

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

Gases and vacua handbook of vacuum physics

CERN Document Server

Beck, A H

2013-01-01

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

Hadron Contribution to Vacuum Polarisation

CERN Document Server

Davier, M; Malaescu, B; Zhang, Z

2016-01-01

Precision tests of the Standard Theory require theoretical predictions taking into account higher-order quantum corrections. Among these vacuum polarisation plays a predominant role. Vacuum polarisation originates from creation and annihilation of virtual particle–antiparticle states. Leptonic vacuum polarisation can be computed from quantum electrodynamics. Hadronic vacuum polarisation cannot because of the non-perturbative nature of QCD at low energy. The problem is remedied by establishing dispersion relations involving experimental data on the cross section for e+ e− annihilation into hadrons. This chapter sets the theoretical and experimental scene and reviews the progress achieved in the last decades thanks to more precise and complete data sets. Among the various applications of hadronic vacuum polarisation calculations, two are emphasised: the contribution to the anomalous magnetic moment of the muon, and the running of the fine structure constant α to the Z mass scale. They are fundamental ingre...

Helical type vacuum container

International Nuclear Information System (INIS)

Owada, Kimio.

1989-01-01

Helical type vacuum containers in the prior art lack in considerations for thermal expansion stresses to helical coils, and there is a possibility of coil ruptures. The object of the present invention is to avoid the rupture of helical coils wound around the outer surface of a vacuum container against heat expansion if any. That is, bellows or heat expansion absorbing means are disposed to a cross section of a helical type vacuum container. With such a constitution, thermal expansion of helical coils per se due to temperature elevation of the coils during electric supply can be absorbed by expansion of the bellows or absorption of the heat expansion absorbing means. Further, this can be attained by arranging shear pins in the direction perpendicular to the bellows axis so that the bellows are not distorted when the helical coils are wound around the helical type vacuum container. (I.S.)

PDX vacuum vessel stress analysis

International Nuclear Information System (INIS)

Nikodem, Z.D.

1975-01-01

A stress analysis of PDX vacuum vessel is described and the summary of results is presented. The vacuum vessel is treated as a toroidal shell of revolution subjected to an internal vacuum. The critical buckling pressure is calculated. The effects of the geometrical discontinuity at the juncture of toroidal shell head and cylindrical outside wall, and the concavity of the cylindrical wall are examined. An effect of the poloidal field coil supports and the vessel outside supports on the stress distribution in the vacuum vessel is determined. A method evaluating the influence of circular ports in the vessel wall on the stress level in the vessel is outlined

Fe embedded in ice: The impacts of sublimation and energetic particle bombardment

Science.gov (United States)

Frankland, Victoria L.; Plane, John M. C.

2015-05-01

Icy particles containing a variety of Fe compounds are present in the upper atmospheres of planets such as the Earth and Saturn. In order to explore the role of ice sublimation and energetic ion bombardment in releasing Fe species into the gas phase, Fe-dosed ice films were prepared under UHV conditions in the laboratory. Temperature-programmed desorption studies of Fe/H2O films revealed that no Fe atoms or Fe-containing species co-desorbed along with the H2O molecules. This implies that when noctilucent ice cloud particles sublimate in the terrestrial mesosphere, the metallic species embedded in them will coalesce to form residual particles. Sputtering of the Fe-ice films by energetic Ar+ ions was shown to be an efficient mechanism for releasing Fe into the gas phase, with a yield of 0.08 (Ar+ energy=600 eV). Extrapolating with a semi-empirical sputtering model to the conditions of a proton aurora indicates that sputtering by energetic protons (>100 keV) should also be efficient. However, the proton flux in even an intense aurora will be too low for the resulting injection of Fe species into the gas phase to compete with that from meteoric ablation. In contrast, sputtering of the icy particles in the main rings of Saturn by energetic O+ ions may be the source of recently observed Fe+ in the Saturnian magnetosphere. Electron sputtering (9.5 keV) produced no detectable Fe atoms or Fe-containing species. Finally, it was observed that Fe(OH)2 was produced when Fe was dosed onto an ice film at 140 K (but not at 95 K). Electronic structure theory shows that the reaction which forms this hydroxide from adsorbed Fe has a large barrier of about 0.7 eV, from which we conclude that the reaction requires both translationally hot Fe atoms and mobile H2O molecules on the ice surface.

Thin film CdTe solar cells by close spaced sublimation: Recent results from pilot line

International Nuclear Information System (INIS)

Siepchen, B.; Drost, C.; Späth, B.; Krishnakumar, V.; Richter, H.; Harr, M.; Bossert, S.; Grimm, M.; Häfner, K.; Modes, T.; Zywitzki, O.; Morgner, H.

2013-01-01

CdTe is an attractive material to produce high efficient and low cost thin film solar cells. The semiconducting layers of this kind of solar cell can be deposited by the Close Spaced Sublimation (CSS) process. The advantages of this technique are high deposition rates and an excellent utilization of the raw material, leading to low production costs and competitive module prices. CTF Solar GmbH is offering equipment and process knowhow for the production of CdTe solar modules. For further improvement of the technology, research is done at a pilot line, which covers all relevant process steps for manufacture of CdTe solar cells. Herein, we present the latest results from the process development and our research activities on single functional layers as well as for complete solar cell devices. Efficiencies above 13% have already been obtained with Cu-free back contacts. An additional focus is set on different transparent conducting oxide materials for the front contact and a Sb 2 Te 3 based back contact. - Highlights: ► Laboratory established on industrial level for CdTe solar cell research ► 13.0% cell efficiency with our standard front contact and Cu-free back contact ► Research on ZnO-based transparent conducting oxide and Sb 2 Te 3 back contacts ► High resolution scanning electron microscopy analysis of ion polished cross section

Theoretical and instrumental aspects of preparation of radioactive sources for precise nuclear spectroscopy

International Nuclear Information System (INIS)

Babenkov, M.I.; Kadyrzhanov, K.K.; Zhdanov, V.S.

2005-01-01

Full text: Precise investigations of spectra from nuclear radiations are quite sensitive to quality of radiation sources used. In an ideal case a source should introduce no noticeable distortion into registered spectrum. In spectroscopy of low-energy gamma-quanta, electrons and alpha particles sample preparation quite frequently turns to be challenging independent scientific investigation. Source preparation is conventionally performed at two stages - extraction of activity from a target and its uniform distribution over a substrate. A general requirement to such radioactive layer is maximal total and specific activity. Unfortunately, there is no universal source preparation method currently available for precise spectroscopy. In a number of cases excellent results are provided by fractional sublimation method based on ability of some elements to evaporate from target material at heating. The method demonstrates a several advantages. The paper introduces a complex of experimental equipment for preparation of high-quality radioactive sources. This complex is arranged in a well-protected heavy box equipped with master-slave manipulators. Biological protection of the box makes it possible to handle activities up to 10 11 Bq. Main part of the complex is a special vacuum post that assures works with active samples in the vacuum up to 10 -7 mm Hg - the operations include fractional sublimation, thermal evaporation, thermal diffusion, evaporation by electron beam, etc. All units of the vacuum post arranged in the box are designed to work with master-slave manipulators. The post is mainly used for preparation of a high-quality beta sources and extraction of microamounts of radionuclides from reactor and cyclotron targets by the method of fractional sublimation. Another important unit of the complex is an equipment for selective chemisorption in vacuum. Complex comprises all required auxiliary equipment The entire complex operated at high rate of reliability. The paper pays

Quark and gluon condensate in vacuum

International Nuclear Information System (INIS)

Vajnshtejn, A.I.; Zakharov, V.I.; Shifman, M.A.

1979-01-01

The mechanism of quark confinement has been reviewed. The fact that coloured particles in a free state cannot be observed is connected with specific properties of vacuum in quantum chromodynamics. The basic hypothesis consists in the existence of vacuum fields, quark and gluon condensates, which affect the coloured objects. The vacuum transparent relative to noncharged ''white'' states serves as a source of the force acting upon the coloured particles. It has been a sucess to examine strictly the action of the vacuum fields on quarks when the distance between them is relatively small and the force of the vacuum fields on quarks is relatively small too. It is shown that the interaction with the vacuum fields manifests itself earlier than the forces connected with the gluon exchange do. It is assumed that the vacuum condensate of quarks and gluons and its relation to properties of resonances and to the bag model exist in reality. The dispersion sum rules are used for calculating masses and lepton widths of resonances

CAS CERN Accelerator School vacuum technology. Proceedings

International Nuclear Information System (INIS)

Turner, S.

1999-01-01

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

Drying of encapsulated parts (nuclear fuel rods) in applying vacuum, by introducing dehydratings, vacuum, and filling with an inert gas

International Nuclear Information System (INIS)

Johnson, C.R.

1976-01-01

This invention concerns a decontamination technique, in particular a process and equipment for extracting the water contained in fuel rods and other similar components of a nuclear reactor. The extraction of the contaminants contained in the fuel rods is carried out by a standard method by drilling a small hole in the surface of the cladding and applying a vacuum to bleed the rod of its impurities (moisture and gas). The invention consists for example in applying a vacuum at the hole drilled in the cladding to extract the contaminants and introducing spirit into the rod through the same orifice. The spirit absorbs the remaining liquid and other impurities. The spirit charged with the impurities is then pumped out by the same aperture by means of a regulated atmosphere inside a closed receptacle. This receptacle is then filled with an inert gas cooled to ambient temperature. The rods are then pressurised and the small orifice is sealed [fr

ULTRARAPID VACUUM-MICROWAVE HISTOPROCESSING

NARCIS (Netherlands)

KOK, LP; BOON, ME

A novel histoprocessing method for paraffin sections is presented in which the combination of vacuum and microwave exposure is the key element. By exploiting the decrease in boiling temperature under vacuum, the liquid molecules in the tissues have been successfully extracted and exchanged at

An intense lithium ion beam source using vacuum baking and discharge cleaning techniques

International Nuclear Information System (INIS)

Moschella, J.J.; Kusse, B.R.; Longfellow, J.P.; Olson, J.C.

1991-01-01

We have developed a high-purity, intense, lithium ion beam source which operates at 500 kV and 120 A/cm 2 with pulse widths of 125 ns full width half maximum. The beams were generated using a lithium chloride anode in planar magnetically insulated geometry. We have found that the combination of vacuum baking of the anode at 250 degree C followed by the application of 100 W of pure argon, steady-state, glow discharge cleaning reduced the impurity concentration in the beam to approximately 10% (components other than chlorine or lithium were considered impurities). Although the impurities were low, the concentration of chlorine in the 1+ and 2+ charge states was significant (∼25%). The remaining 65% of the beam consisted of Li + ions. Without the special cleaning process, over half the beam particles were impurities. It was determined that these impurities entered the beam at the anode surface but came originally from material in the vacuum chamber. After the cleaning process, recontamination was observed to occur in approximately 6 min. This long recontamination time, which was much greater than the expected monolayer formation time, was attributed to the elevated temperature of the anode. We also compared the electrical characteristics of the beams produced by LiCl anodes to those generated by a standard polyethylene proton source. In contrast to the polyethylene anode, the LiCl source exhibited a higher impedance, produced beams of lower ion current efficiency and had longer turn on times

Selection of vacuum seals for EBT-P

International Nuclear Information System (INIS)

Dillow, C.F.; Adlon, G.L.; Stubblefield, V.E.

1981-01-01

Elmo Bumpy Torus Proof of Principle (EBT-P) is a magnetic fusion RandD facility being constructed by McDonnell Douglas Astronautics Company - St. Louis Division of Oak Ridge National Laboratory (ORNL). EBT-P is a truly unique fusion device requiring careful consideration in selecting both the primary vacuum seals on the toroidal vessel and the secondary vacuum seals in components such as vacuum pumps and and valves. The vacuum seal environment is described and the considerations in vacuum seal selection fully discussed. Methods for protecting vacuum seals in pumps and valves from the microwave environments are also presented

Lepanto, before and after: Between the Republic and the Sublime Porte

Directory of Open Access Journals (Sweden)

Özlem KUMRUlAR

2014-12-01

Full Text Available The loss of Cyprus to the ottoman Turks, hand in hand with the Battle of Lepanto was the major reason of a period of frozen politics and caused the breaking of the traditional peace between Venice and Constantinople. Yet there is a notable difference between the historical and political Conseptualization of these two major episodes. The ottoman state didn’t interpret this catastrophe as the Republic did. As, it could be seen from the bilateral diplomacy carried out by both states, neither the loss of Cyprus, nor the myth-creating Lepanto could change the classical oriental policy of the Serenissima. The case was not different for the Sublime Porte. The aim of this paper is to analyse the post-war politics of these two states and the noteable change in the political polarization in Europe in the milieu of the ottoman-Hapsburg rivalry.

Vacuum transitions in dual models

International Nuclear Information System (INIS)

Pashnev, A.I.; Volkov, D.V.; Zheltukhin, A.A.

1976-01-01

The investigation is continued of the spontaneous vacuum transition problem in the Neview-Schwartz dual model (NSDM). It is shown that vacuum transitions allow disclosing of supplementary degeneration in the resonance state spectrum. The dual amplitudes possess an internal structure corresponding to the presence of an infinite number of quarks with increasing masses and retained charges. The Adler principle holds. Analytic continuation on the constant of induced vacuum transitions makes it possible to establish the existence of spontaneous vacuum transitions in the NSDM. The consequence of this fact is the exact SU(2) symmetry of π, rho meson trajectories and the Higgs mechanism in the model. In this case the ratios of masses of particles leading trajectories are analogous to those obtained in the current algebra. It is shown that in the NSDM there arises chiral SU(2) x SU(2) x U(1) x U(1) x ... symmetry resulting from spontaneous vacuum transitions

Vacuum maintenance in vacuum insulation panels exemplified with a staggered beam VIP

Energy Technology Data Exchange (ETDEWEB)

Kwon, Jae-Sung; Jang, Choong Hyo; Jung, Haeyong; Song, Tae-Ho [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Guseong-dong 373-1, Yuseong-gu, Daejeon (Korea, Republic of)

2010-05-15

Thermal insulation performance of a vacuum insulation panel (VIP) is highly dependent on the inner pressure of the VIP. Long-term vacuum maintenance characteristics are investigated in this study for a VIP with an example of polymer staggered beam structure as the core material. Various gas sources deteriorating the vacuum level in the VIP are investigated based on theoretical models and experiments. Gas permeation occurring through heat-sealed flanges and pinholes in the barrier envelope is the largest gas leakage source. The calculated gas permeation rate is in accordance with the experimental result. To reduce these permeations, a three-side sealing envelope and double enveloping are proposed. Outgassing from the core material and inner surface of the envelope is also critical. It is significantly reduced by a baking pre-treatment in vacuum. When the estimated total gas load exceeds the allowable limit within a few years, a getter material may be applied. Double enveloping structure with a getter is promising as it ensures a lifetime of more than 20 years. (author)

Vacuum guidelines for ISA insertions

International Nuclear Information System (INIS)

Edwards, D. Jr.

1976-01-01

Vacuum requirements place design restrictions on the ISA insertions. The vacuum tube diameter, given a distance L between pumps, is determined by the desorption of molecules from the wall under the impact of ions created by the beam, whereas the thickness of the tube must be sufficient to prevent collapse. In addition, the entire vacuum chamber must be able to be baked out at approximately 200 0 C

Particle contamination in vacuum systems

International Nuclear Information System (INIS)

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

1996-01-01

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

Particle contamination in vacuum systems

International Nuclear Information System (INIS)

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

1996-01-01

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

Changes in non-volatile taste components of button mushroom (Agaricus bisporus) during different stages of freeze drying and freeze drying combined with microwave vacuum drying.

Science.gov (United States)

Pei, Fei; Shi, Ying; Gao, Xingyang; Wu, Fangning; Mariga, Alfred Mugambi; Yang, Wenjian; Zhao, Liyan; An, Xinxin; Xin, Zhihong; Yang, Fangmei; Hu, Qiuhui

2014-12-15

Button mushroom slices were dehydrated using freeze drying (FD) or FD combined with microwave vacuum drying (FMVD), and the non-volatile component profiles were studied. The results showed that the level of non-volatile components in button mushroom firstly increased during sublimation of FD/FMVD process and then fell during desorption in FD process and MVD in FMVD process. Compared to FD products, the contents of soluble sugars and polyols in FMVD products were relatively low, whereas the contents of total free amino acids were significantly higher, close to the level of fresh mushroom. However, there was no significant difference in the contents of 5'-nucleotides and organic acids between FD and FMVD products. The equivalent umami concentration (EUC) values for FD and FMVD products did not differ from fresh, indicating that both drying methods could effectively preserve MSG (monosodium glutamate)-like components in button mushroom. Copyright © 2014 Elsevier Ltd. All rights reserved.

Research on vacuum insulation for cryocables

International Nuclear Information System (INIS)

Graneau, P.

1974-01-01

Vacuum insulation, as compared with solid insulation, simplifies the construction of both resistive or superconducting cryogenic cables. The common vacuum space in the cable can furnish thermal insulation between the environment and the cryogenic coolant, provide electrical insulation between conductors, and establish thermal isolation between go- and return-coolant streams. The differences between solid and vacuum high voltage insulation are discussed, and research on the design, materials selection, and testing of vacuum insulated cryogenic cables is described

Vacuum-insulated catalytic converter

Science.gov (United States)

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.

Barium Ferrite Ball Milled in Vacuum

International Nuclear Information System (INIS)

Campbell, S.J.; Wu, E.; Kaczmarek, W.A.; Wang, G.

1998-01-01

The structural and magnetic behaviour of BaFe 12 O 19 subjected to milling in vacuum for 1000 h has been investigated by x-ray powder diffraction and Moessbauer effect spectroscopy techniques. Pronounced structural disorder is obtained along with partial decomposition of BaFe 12 O 19 to α-Fe 2 O 3 and evidence for superparamagnetic relaxation effects due to the fine particles produced on milling. Restoration of the fully crystallised BaFe 12 O 19 structure on annealing at 1000 deg. C is accompanied by a six fold enhancement in the magnetic coercivity. This behaviour is linked with the fine crystallites

Protective coating of inner surface of steel tubes via vacuum arc deposition

Energy Technology Data Exchange (ETDEWEB)

Maile, K.; Roos, E.; Lyutovich, A.; Boese, J.; Itskov, M. [Stuttgart Univ. (DE). Materialpruefungsanstalt (MPA); Ashurov, Kh.; Mirkarimov, A.; Kazantsev, S.; Kadirov, Kh. [Uzbek Academy of Science, Tashkent (Uzbekistan). Arifov Inst. of Electronics

2010-07-01

The Vacuum Arc Deposition (VAD) technique based on sputtering a chosen electrode material and its deposition via plasma allows highly-productive technology for creating a wide class of protecting coatings on complex structures. In this work, VAD was applied as a method for the protection of the inner surface of tubes for power-plant boilers against steam oxidation. For this aim, a source cathode of an alloy with high chromium and nickel content was employed in two different VAD treatment systems: a horizontal vacuum chamber (MPA) and a vertical system where the work-piece of the tubes to be protected served as a vacuum changer (Arifov Institute of Electronics). Surface coating with variation of deposition parameters and layer thickness was performed. Characterisation of coated tubes has shown that the method realised in this work allows attainment of material transfer from the cathode to the inner surface with nearly equal chemical composition. It was demonstrated that the initial martensitic structure of the tubes was kept after the vacuum-arc treatment which can provide for both the high mechanical robustness and the corrosion-resistance of the final material. (orig.)

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

Energy Technology Data Exchange (ETDEWEB)

IRWIN, J.J.

1998-11-30

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

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

International Nuclear Information System (INIS)

IRWIN, J.J.

1998-01-01

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

Color-magnetic permeability of QCD vacuum

Energy Technology Data Exchange (ETDEWEB)

Saito, T [Kyoto Prefectural Univ. of Medicine (Japan); Shigemoto, K

1980-03-01

In the very strong background gauge field the QCD true vacuum has been shown to have lower energy than the ''perturbative vacuum.'' The color-magnetic permeability of the QCD true vacuum is then calculated to be 1/2 within the quark-one-loop approximation.

Vacuum vessel for thermonuclear device

International Nuclear Information System (INIS)

Kikuchi, Mitsuru; Kurita, Gen-ichi; Onozuka, Masaki; Suzuki, Masaru.

1997-01-01

Heat of inner walls of a vacuum vessel that receive radiation heat from plasmas by way of first walls is removed by a cooling medium flowing in channels for cooling the inner walls. Nuclear heat generation of constitutional materials of the vacuum vessel caused by fast neutrons and γ rays is removed by a cooling medium flowing in cooling channels disposed in the vacuum vessel. Since the heat from plasmas and the nuclear heat generation are removed separately, the amount of the cooling medium flowing in the channels for cooling inner walls is increased for cooling a great amount of heat from plasmas while the amount of the cooling medium flowing in the channels for cooling the inside of the vacuum vessel is reduced for cooling the small amount of nuclear heat generation. Since the amount of the cooling medium can thus be optimized, the capacity of the facilities for circulating the cooling medium can be reduced. In addition, since the channels for cooling the inner walls and the channels of cooling medium formed in the vacuum vessel are disposed to the inner walls of the vacuum vessel on the side opposite to plasmas, integrity of the channels relative to leakage of the cooling medium can be ensured. (N.H.)

Vacuum vessel for thermonuclear device

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Mitsuru; Kurita, Gen-ichi [Japan Atomic Energy Research Inst., Tokyo (Japan); Onozuka, Masaki; Suzuki, Masaru

1997-07-31

Heat of inner walls of a vacuum vessel that receive radiation heat from plasmas by way of first walls is removed by a cooling medium flowing in channels for cooling the inner walls. Nuclear heat generation of constitutional materials of the vacuum vessel caused by fast neutrons and {gamma} rays is removed by a cooling medium flowing in cooling channels disposed in the vacuum vessel. Since the heat from plasmas and the nuclear heat generation are removed separately, the amount of the cooling medium flowing in the channels for cooling inner walls is increased for cooling a great amount of heat from plasmas while the amount of the cooling medium flowing in the channels for cooling the inside of the vacuum vessel is reduced for cooling the small amount of nuclear heat generation. Since the amount of the cooling medium can thus be optimized, the capacity of the facilities for circulating the cooling medium can be reduced. In addition, since the channels for cooling the inner walls and the channels of cooling medium formed in the vacuum vessel are disposed to the inner walls of the vacuum vessel on the side opposite to plasmas, integrity of the channels relative to leakage of the cooling medium can be ensured. (N.H.)

Fast space travel by vacuum zero-point field perturbations

International Nuclear Information System (INIS)

Froning, H. D. Jr.

1999-01-01

Forces acting upon an accelerating vehicle that is 'warping' its surrounding space are estimated, using the techniques of computational gas/fluid dynamics. Disturbances corresponding to perturbation of spacetime metric and vacuum zero-point fields by electromagnetic discharges are modeled as changes in the electric permittivity and magnetic permeability characteristics of the vacuum of space. And it is assumed that resistance to acceleration (vehicle inertia) is, in part, a consequence of zero-point radiation pressure field anisotropy in the warped space region surrounding the craft. The paper shows that resistance to vehicle acceleration can be diminished by spacetime warping that increases light propagation speed within the warped region. If sufficient warping is achieved, ship speed is slower than light speed within the region that surrounds it-even if it is moving faster-than-light with respect to earth

Physical, Mechanical, and Morphological Properties of Woven Kenaf/Polymer Composites Produced Using a Vacuum Infusion Technique

Directory of Open Access Journals (Sweden)

Suhad D. Salman

2015-01-01

Full Text Available Nowadays, due to renewable issues, environmental concerns, and the financial problems of synthetic fibres, the development of high-performance engineering products made from natural resources is increasing all over the world. Lately, kenaf fibre has been used among many different types of natural resources in various shapes. Unidirectional long fibres or randomly oriented short fibre shapes are the most common type of kenaf fibres that have been investigated in previous works. This work characterises and evaluates the physical, mechanical, and morphological properties of plain woven kenaf fabric and its composites with three types of thermoset resin at 0°/90° and 45°/−45° orientation, in order to assess their suitability as lignocellulosic reinforced polymer composites. A vacuum infusion manufacturing technique was used to prepare the specimens with fibre weight content of 35% ± 2%. Eight specimens were prepared for each test, and five replications were adopted. A total of 78 samples were tested in this study. The results show that the composites with 0°/90° had the highest tensile, flexural strengths, and modulus. The morphological properties of composite samples were analysed through scanning electron microscopy (SEM images and these clearly demonstrated the better interfacial adhesion between the woven kenaf and the epoxy matrix.

Ultra high vacuum systems for accelerators

International Nuclear Information System (INIS)

Loefgren, P.

2001-01-01

Full text: In order to perform controlled, stable, and reproducible experiments, several research areas today require very low pressures. Maybe the most important example is the research that is performed in storage rings and accelerators where the lifetime and stability of particle beams depends critically on the vacuum conditions. Although the vacuum requirements ultimately depend on the kind of experiments that is performed, the studies of more and more rare and exotic species in storage rings and accelerators today pushes the demands on the vacuum conditions towards lower and lower pressures. The final pressure obtained in the vacuum system can often be the key factor for the outcome of an experiment. Pioneering work in vacuum technology has therefore often been performed at storage rings and accelerator facilities around the world. In order to reach pressures in the low UHV regime and lower (below 10 -11 mbar), several aspects have to be considered which implies choosing the proper materials, pumps and vacuum gauges. In the absence of gases inleaking from the outside, the rate of gas entering a vacuum system is determined by the release of molecules adsorbed on the surfaces and the outgassing from the bulk of the vacuum chamber walls. This means that the choice of material and, equally important, the pre treatment of the material, must be such that these rates are minimised. Today the most widely used material for vacuum applications are stainless steel. Besides its many mechanical advantages, it is resistant to corrosion and oxidation. If treated correctly the major gas source in a stainless steel chamber is hydrogen outgassing from the chamber walls. The hydrogen outgassing can be decreased by vacuum firing at 950 deg. C under vacuum. In addition to choosing the right materials the choice of vacuum pumps is important for the final pressure. Since no vacuum pump is capable of taking care of all kinds of gases found in the rest gas at pressures below 10 -11

Wireless Integrated Microelectronic Vacuum Sensor System

Science.gov (United States)

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

Baking results of KSTAR vacuum vessel

International Nuclear Information System (INIS)

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

2009-01-01

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

Baking results of KSTAR vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

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

2009-05-15

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

Realisation of a ultra-high vacuum system and technique development of microscopical emitters preparation in silicium. First measurements of field emission current and field photoemission

International Nuclear Information System (INIS)

El Manouni, A.

1990-12-01

The development of research in the domain of photocathode (electron sources) illuminated by laser light to produce intense multiple bunches of electrons in short time is needed by many applications as linear collider e + e - , free electron laser, lasertron, etc... In this way, after a study of field emission, of photoemission and of photofield emission, we prepared microscopical emitters in silicium heavy and weakly doped a boron using a technique of microlithography. Then, we realized a system of ultra-high vacuum of studying property of emission from photocathodes realized. The experiment results obtained in field emission and photofield emission have shown that a behaviour unexpected for P-silicium tips array compared to P + -silicon tips array. With P-type silicon, a quantum yield of 21 percent has been measured for laser power of 140 mW and for applied field of 1.125 x 10 7 V/m and an instantaneous response to laser light beam has been observed. It has been noted that presence of oxyde at the surface of photocathode limits extensively the emission current. The fluctuations of emission current are due to quality of vacuum [fr

VACUUM THERAPY – PREVENTION OF HYPOXIA OF CAVERNOUS TISSUE PATIENTS AFTER RADICAL PROSTATECTOMY

Directory of Open Access Journals (Sweden)

A. E. Osadchinskii

2018-01-01

Full Text Available Patients, after radical prostatectomy with the use of nerve-sparing techniques, without carrying out penile rehabilitation, are at risk of forming cavernous fibrosis with the emergence of subsequent persistent erectile dysfunction. In order to minimize damage to cavernous tissue and early restoration of erectile function during the period of neuropraxia, it is necessary to ensure a sufficient level of oxygenation. The role of applying vacuum in penile rehabilitation for the prevention of hypoxia of cavernous tissue is not fully understood, due to the lack of data on the gaseous composition of the blood at the time of reaching the vacuum of erection. The purpose of this work was to review the scientific studies devoted to the study of vacuum induced penile erection in animals or humans, which indicates high results due to increased oxygenation of cavernous tissue.

Vacuum system of SST-1 Tokamak

International Nuclear Information System (INIS)

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

2013-01-01

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

Evacuation of the NET vacuum chamber

International Nuclear Information System (INIS)

Muller, R.A.

1987-01-01

Parametric calculations of the evacuation process were carried out for the NET-vacuum chamber involving two blanket designs. The results show that with an acceptable vacuum pumping capacity the required start vacuum conditions can be realized within reasonable time. The two blanket concepts do not differ remarkably in their evacuation behaviour. The remaining large pressure differences between the different locations of the vacuum chamber can be reduced if approximately 30% of the total gas flow is extracted from the heads of the blanket replacement ports

Evacuation of the NET vacuum chamber

International Nuclear Information System (INIS)

Mueller, R.

1986-01-01

Parametric calculations of the evacuation process were carried out for the NET-vacuum chamber involving two blanket designs. The results show that with an acceptable vacuum pumping capacity the required start vacuum conditions can be realized within reasonable time. The two blanket concepts do not differ remarkably in their evacuation behaviour. The remaining large pressure differences between the different locations of the vacuum chamber can be reduced if approximately 30% of the total gas flow is extracted from the heads of the blanket replacement ports. (author)

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

Energy Technology Data Exchange (ETDEWEB)

L. C. Cadwallader

2010-06-01

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

Vacuum biopsy of the breast. Experience of St-Jan Hospital in Brugge

International Nuclear Information System (INIS)

Steyaert, L.; Van Kerkhove, F.; Casselman, J.

2004-01-01

Background. Mammotome is a percutaneous biopsy technique with a large needle, assisted by vacuum aspiration. The single insertion technique allows to collect multiple large tissue samples, which gives a more reliable histological result. The technique can be used under stereotactic, MRI or ultrasound guidance. The technique is used under local anesthesia, on an outpatient basis. Conclusions. Altough it is essentially a diagnostic technique, it has a therapeutic potential in some cases. Recently, the technique has been FDA approved for the removal of benign nodular lesions. Worldwide, over 2 million procedures have already been performed. It has the potential to replace surgical open biopsy, with a similar accuracy and at a lower cost, and it is less invasive. (author)

Baking technique of JT-60

Energy Technology Data Exchange (ETDEWEB)

Arai, Takashi; Masaki, Kei; Miyachi, Kengo [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

1998-10-01

It needs to make low ultimate pressure to decrease impurities in a plasma in a nuclear fusion device. Baking technique is very effective method to decrease outgassing rate from first walls and inner surface of the vacuum vessel. However, in such large vacuum vessel, e.g. JT-60, the non-uniform heating and the deformation due to thermal expansion might be very important problems. The baking technique of JT-60 is described. Two baking systems were applied to JT-60 to solve the problem of non-uniform heating. One is a circulation system of the hot nitrogen gas which is located between the inner and outer skins of the double-skin structured vacuum vessel. The other is an electric heater which apply the thick of the vessel. In order to prevent the deformation, the difference of temperature was as small as possible. By both the baking at 300degC and the conditioning such as discharge cleaning, the ultimate pressure was achieved 7.9x10{sup -7} Pa. (author)

Baking technique of JT-60

International Nuclear Information System (INIS)

Arai, Takashi; Masaki, Kei; Miyachi, Kengo

1998-01-01

It needs to make low ultimate pressure to decrease impurities in a plasma in a nuclear fusion device. Baking technique is very effective method to decrease outgassing rate from first walls and inner surface of the vacuum vessel. However, in such large vacuum vessel, e.g. JT-60, the non-uniform heating and the deformation due to thermal expansion might be very important problems. The baking technique of JT-60 is described. Two baking systems were applied to JT-60 to solve the problem of non-uniform heating. One is a circulation system of the hot nitrogen gas which is located between the inner and outer skins of the double-skin structured vacuum vessel. The other is an electric heater which apply the thick of the vessel. In order to prevent the deformation, the difference of temperature was as small as possible. By both the baking at 300degC and the conditioning such as discharge cleaning, the ultimate pressure was achieved 7.9x10 -7 Pa. (author)

Big Bang or vacuum fluctuation

International Nuclear Information System (INIS)

Zel'dovich, Ya.B.

1980-01-01

Some general properties of vacuum fluctuations in quantum field theory are described. The connection between the ''energy dominance'' of the energy density of vacuum fluctuations in curved space-time and the presence of singularity is discussed. It is pointed out that a de-Sitter space-time (with the energy density of the vacuum fluctuations in the Einstein equations) that matches the expanding Friedman solution may describe the history of the Universe before the Big Bang. (P.L.)

The role of defects in fluorescent silicon carbide layers grown by sublimation epitaxy

DEFF Research Database (Denmark)

Schimmel, Saskia; Kaiser, Michl; Jokubavicius, Valdas

Donor-acceptor co-doped silicon carbide layers are promising light converters for novel monolithic all-semiconductor LEDs due to their broad-band donor-acceptor pair luminescence and potentially high internal quantum efficiency. Besides appropriate doping concentrations yielding low radiative...... lifetimes, high nonradiative lifetimes are crucial for efficient light conversion. Despite the excellent crystalline quality that can generally be obtained by sublimation epitaxy according to XRD measurements, the role of defects in f-SiC is not yet well understood. Recent results from room temperature...... photoluminescence, charge carrier lifetime measurements by microwave detected photoconductivity and internal quantum efficiency measurements suggest that the internal quantum efficiency of f-SiC layers is significantly affected by the incorporation of defects during epitaxy. Defect formation seems to be related...

Vacuum vessel for thermonuclear device

International Nuclear Information System (INIS)

Kikuchi, Mitsuru; Nagashima, Keisuke; Suzuki, Masaru; Onozuka, Masaki.

1997-01-01

A vacuum vessel main body and structural members at the inside and the outside of the vacuum vessel main body are constituted by structural materials activated by irradiation of neutrons from plasmas such as stainless steels. Shielding members comprising tungsten or molybdenum are disposed on the surface of the vacuum vessel main body and the structural members of the inside and the outside of the main body. The shielding members have a function also as first walls or a seat member for the first walls. Armor tiles may be disposed to the shielding members. The shielding members and the armor tiles are secured to a securing seat member disposed, for example, to an inner plate of the vacuum vessel main body by bolts. Since the shielding members are disposed, it is not necessary to constitute the vacuum vessel main body and the structural members at the inside and the outside thereof by using a low activation material which is less activated, such as a titanium alloy. (I.N.)

Vacuum vessel for thermonuclear device

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Mitsuru; Nagashima, Keisuke [Japan Atomic Energy Research Inst., Tokyo (Japan); Suzuki, Masaru; Onozuka, Masaki

1997-07-11

A vacuum vessel main body and structural members at the inside and the outside of the vacuum vessel main body are constituted by structural materials activated by irradiation of neutrons from plasmas such as stainless steels. Shielding members comprising tungsten or molybdenum are disposed on the surface of the vacuum vessel main body and the structural members of the inside and the outside of the main body. The shielding members have a function also as first walls or a seat member for the first walls. Armor tiles may be disposed to the shielding members. The shielding members and the armor tiles are secured to a securing seat member disposed, for example, to an inner plate of the vacuum vessel main body by bolts. Since the shielding members are disposed, it is not necessary to constitute the vacuum vessel main body and the structural members at the inside and the outside thereof by using a low activation material which is less activated, such as a titanium alloy. (I.N.)

Enthalpy of sublimation/vaporization of trans-cyclohexyl-1,4-diamine and cis-cyclohexyl-1,2-diamine

OpenAIRE

Tomé, Luciana I. N.; Rosado, Mário T. S.; Nunes, Sandra C. C.; Maria, Teresa M. R.; Canotilho, João; Eusébio, M. Ermelinda S.

2007-01-01

The molar enthalpy of sublimation, , of trans-cyclohexyl-1,4-diamine and the molar enthalpy of vaporization, , of cis-cyclohexyl-1,2-diamine, at the temperature 298.15 K, were determined by calorimetry. was obtained for the trans-isomer and for the cis form. The molar enthalpy of fusion of the first compound, at T = 342.1 K, was determined by differential scanning calorimetry. The molar enthalpy of vaporization of the 1,4-isomer was estimated by combining the value of the enthalpy of sublimat...

Definition of the chief physical quantities in use in vacuum techniques, and their corresponding units

International Nuclear Information System (INIS)

Boulassier, J.C.

1959-01-01

It would seem desirable for vacuum technicians to adopt the coherent systems of units generally used in physics. This article presents an internal standardisation project in the CEA, and gives a brief review of the definitions of the physical quantities to which it applies. Reprint of a paper published in 'Le vide', n. 79, January-February 1959, p. 29-35 [fr

Vacuum status-display and sector-conditioning programs

International Nuclear Information System (INIS)

Skelly, J.; Yen, S.

1989-01-01

Two programs have been developed for observation and control of the AGS vacuum system, which include these notable features: they incorporate a graphical user interface, and 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 for several hours. As additional devices are installed in the vacuum system, the devices are likewise added to the relational database; these programs then automatically include the new devices. 2 refs., 1 fig

Dynamical effects of QCD vacuum structure

International Nuclear Information System (INIS)

Ferreira, Erasmo

1994-01-01

The role of the QCD vacuum structure in the determination of the properties of states and processes occurring in the confinement regime of QCD is reviewed. The finite range of the vacuum correlations is discussed, and an analytical form is suggested for the correlation functions. The role of the vacuum quantum numbers in the phenomenology of high-energy scattering is reviewed. The vacuum correlation model of non-perturbative QCD is mentioned as a bridge between the fundamental theory and the description of the experiments. (author). 13 refs., 1 fig

Vacuum technology in the chemical industry

CERN Document Server

Jorisch, Wolfgang

2015-01-01

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

Running vacuum cosmological models: linear scalar perturbations

Energy Technology Data Exchange (ETDEWEB)

Perico, E.L.D. [Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, CEP 05508-090, São Paulo, SP (Brazil); Tamayo, D.A., E-mail: elduartep@usp.br, E-mail: tamayo@if.usp.br [Departamento de Astronomia, Universidade de São Paulo, Rua do Matão 1226, CEP 05508-900, São Paulo, SP (Brazil)

2017-08-01

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 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 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.

46 CFR 154.804 - Vacuum protection.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Vacuum protection. 154.804 Section 154.804 Shipping... Systems § 154.804 Vacuum protection. (a) Except as allowed under paragraph (b) of this section, each cargo tank must have a vacuum protection system meeting paragraph (a)(1) of this section and either paragraph...

Spectrometric techniques 4

CERN Document Server

Vanasse, George A

2013-01-01

Spectrometric Techniques, Volume IV discusses three widely diversified areas of spectrometric techniques. The book focuses on three spectrometric methods. Chapter 1 discusses the phenomenology and applications of Coherent Anti-Stokes Raman Spectroscopy (CARS), the most commonly used optical technique that exploit the Raman effect. The second chapter is concerned with diffraction gratings and mountings for the Vacuum Ultraviolet Spectral Region. Chapter 3 accounts the uses of mass spectrometry, detectors, types of spectrometers, and ion sources. Physicists and chemists will find the book a go

Spectrometric techniques 2

CERN Document Server

Vanasse, George A

2013-01-01

Spectrometric Techniques, Volume II provides information pertinent to vacuum ultraviolet techniques to complete the demonstration of the diversity of methods available to the spectroscopist interested in the ultraviolet visible and infrared spectral regions. This book discusses the specific aspects of the technique of Fourier transform spectroscopy.Organized into five chapters, this volume begins with an overview of the large number of systematic effects in the recording of an interferogram. This text then examines the design approach for a Fourier transform spectrometer with focus on optics.

Vacuum Mechatronics And Insvection For Self-Contained Manufacturing

Science.gov (United States)

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

1990-02-01

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

Vacuum system for HIMAC synchrotrons

International Nuclear Information System (INIS)

Kanazawa, M.; Sudou, M.; Sato, K.

1994-01-01

HIMAC synchrotrons are now under construction, which require vacuum chambers of large aperture and high vacuum of about 10 -9 torr. Wide thin wall vacuum chamber of 0.3 mm thickness reinforced with ribs has been developed as the chamber at dipole magnet. We have just now started to evacuate the lower ring. The obtained average value was about 5x10 -8 torr with turbo-molecular and sputter ion pumps, and 1.1x10 -9 torr after baking. (author)

Vacuum vessel for thermonuclear device

International Nuclear Information System (INIS)

Hagiwara, Koji; Imura, Yasuya.

1979-01-01

Purpose: To provide constituted method for easily performing baking of vacuum vessel, using short-circuiting segments. Constitution: At the time of baking, one turn circuit is formed by the vacuum vessel and short-circuiting segments, and current transformer converting the one turn circuit into a secondary circuit by the primary coil and iron core is formed, and the vacuum vessel is Joule heated by an induction current from the primary coil. After completion of baking, the short-circuiting segments are removed. (Kamimura, M.)

ITER diagnostic system: Vacuum interface

Energy Technology Data Exchange (ETDEWEB)

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

2013-10-15

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

ITER diagnostic system: Vacuum interface

International Nuclear Information System (INIS)

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

2013-01-01

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

Experimental measurement of magnetic field null in the vacuum chamber of KTM tokamak based on matrix of 2D Hall sensors

Energy Technology Data Exchange (ETDEWEB)

Shapovalov, G.; Chektybayev, B., E-mail: chektybaev@nnc.kz; Sadykov, A.; Skakov, M.; Kupishev, E.

2016-11-15

Experimental technique of measurement of magnetic field null region inside of the KTM tokamak vacuum chamber has been developed. Square matrix of 36 2D Hall sensors, which used in the technique, allows carrying out direct measurements of poloidal magnetic field dynamics in the vacuum chamber. To better measuring accuracy, Hall sensor’s matrix was calibrated with commercial Helmholtz coils and in situ measurement of defined magnetic field from poloidal and toroidal coils. Standard KTM Data-Acquisition System has been used to collect data from Hall sensors. Experimental results of measurement of magnetic field null in the vacuum chamber of KTM are shown in the paper. Additionally results of the magnetic field null reconstruction from signals of inductive total flux loops are shown in the paper.

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

Science.gov (United States)

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

2012-11-01

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

Vacuum system of SST-1 Tokamak

Energy Technology Data Exchange (ETDEWEB)

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

2013-10-15

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

Rotary bayonets for cryogenic and vacuum service

International Nuclear Information System (INIS)

Rucinski, R.A.; Dixon, K.D.; Krasa, R.; Krempetz, K.J.; Mulholland, G.T.; Trotter, G.R.; Urbin, J.B.

1993-07-01

Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation between the male and female pipe sections while maintaining integrity of service. Assemblies using three such joints were built to allow end connection points to be translated through at least 1 meter of horizontal travel while kept in service. Vacuum jacketed sizes built in-house at Fermi National Accelerator Laboratory are 1-1/2 in. inner pipe size, 3 in. vacuum jacket, and 4 in. inner pipe size, 6 in. vacuum jacket The single wall vacuum service bayonets are in 4 in. and 6 in. pipe sizes. The bayonets have successfully been in active service for over one year

Rotary bayonets for cryogenic and vacuum service

International Nuclear Information System (INIS)

Rucinski, R.A.; Dixon, K.D.; Krasa, R.; Krempetz, K.J.; Mulholland, G.T.; Trotter, G.R.; Urbin, J.B.

1994-01-01

Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation between the male and female pipe sections while maintaining integrity of service. Assemblies using three such joints were built to allow end connection points to be translated through at least 1 meter of horizontal travel while kept in service. Vacuum jacketed sizes built in-house at Fermi National Accelerator Laboratory are 1 1/2 inches inner pipe size, 3 inches vacuum jacket, and 4 inches inner pipe size, 6 inches vacuum jacket. The single wall vacuum service bayonets are in 4 inch and 6 inch pipe sizes. The bayonets have successfully been in active service for over one year

Nitrogen pressure in a vacuum system

International Nuclear Information System (INIS)

Edwards, D. Jr.

1977-01-01

Since the N 2 outgassing rate from walls of a vacuum system is generally recognized to be very small, the presence of a N 2 pressure in the system is a useful indication of the presence of real leaks to the atmosphere. A technique of thermal desorption mass spectrometry is introduced which allows the N 2 pressure in the background gas of a baked system to be separated from a CH 4 background to a minimum level of N 2 detectability of approximately 1 percent of the CO background pressure. In typical baked systems (of which an example is given), it is possible to readily determine the sum of all real N 2 leaks to atmosphere at a level of approximately 10 -11 Torr liter/s. This feature makes the technique ideally suited to large complex systems since the leak rate can be evaluated before detailed leak finding procedures are initiated

TPX vacuum vessel transient thermal and stress conditions

International Nuclear Information System (INIS)

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

1995-01-01

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

Selective Area Sublimation: A Simple Top-down Route for GaN-Based Nanowire Fabrication.

Science.gov (United States)

Damilano, B; Vézian, S; Brault, J; Alloing, B; Massies, J

2016-03-09

Post-growth in situ partial SiNx masking of GaN-based epitaxial layers grown in a molecular beam epitaxy reactor is used to get GaN selective area sublimation (SAS) by high temperature annealing. Using this top-down approach, nanowires (NWs) with nanometer scale diameter are obtained from GaN and InxGa1-xN/GaN quantum well epitaxial structures. After GaN regrowth on InxGa1-xN/GaN NWs resulting from SAS, InxGa1-xN quantum disks (QDisks) with nanometer sizes in the three dimensions are formed. Low temperature microphotoluminescence experiments demonstrate QDisk multilines photon emission around 3 eV with individual line widths of 1-2 meV.

Design foundation of vacuum system for electron beam machine

International Nuclear Information System (INIS)

Darsono; Suprapto; Djasiman

1999-01-01

Vacuum system is a main part of electron beam Machine because (EBM) the electron can not be produced without this vacuum. Vacuum system consists of vacuum pump, connecting pipe, valve, and vacuum gauge. The design vacuum system of EBM, basis knowledge and technology of vacuum is needed. The paper describes types of vacuum pump, calculation of pipe conductance and pumping time of vacuum system then there are used as consideration of criteria to choose vacuum pump for EBM. From the result of study, it is concluded that for EBM of 500 keV/10 mA which is going to use for wood coating and with consideration of economic and technic factor it is better to use diffusion pump. (author)

Development of a vacuum superinsulation panel

Energy Technology Data Exchange (ETDEWEB)

Timm, H; Seefeldt, D; Nitze, C

1983-05-01

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

Vacuum phonon tunneling.

Science.gov (United States)

Altfeder, Igor; Voevodin, Andrey A; Roy, Ajit K

2010-10-15

Field-induced phonon tunneling, a previously unknown mechanism of interfacial thermal transport, has been revealed by ultrahigh vacuum inelastic scanning tunneling microscopy (STM). Using thermally broadened Fermi-Dirac distribution in the STM tip as in situ atomic-scale thermometer we found that thermal vibrations of the last tip atom are effectively transmitted to sample surface despite few angstroms wide vacuum gap. We show that phonon tunneling is driven by interfacial electric field and thermally vibrating image charges, and its rate is enhanced by surface electron-phonon interaction.

Comprehending the structure of a vacuum vessel and in-vessel components of fusion machines. 1. Comprehending the vacuum vessel structure

International Nuclear Information System (INIS)

Onozuka, Masanori; Nakahira, Masataka

2006-01-01

The functions, conditions and structure of vacuum vessel using tokamak fusion machines are explained. The structural standard and code of vacuum vessel, process of vacuum vessel design, and design of ITER vacuum vessel are described. Production and maintenance of ultra high vacuum, confinement of radioactive materials, support of machines in vessel and electromagnetic force, radiation shield, plasma vertical stability, one-turn electric resistance, high temperature baking heat and remove of nuclear heat, reduce of troidal ripple, structural standard, features of safety of nuclear fusion machines, subjects of structural standard of fusion vacuum vessel, design flow of vacuum vessel, establishment of radial build, selections of materials, baking and cooling method, basic structure, structure of special parts, shield structure, and of support structure, and example of design of structure, ITER, are stated. (S.Y.)

New Vacuum Electronic Devices for Radar

Directory of Open Access Journals (Sweden)

Hu Yinfu

2016-08-01

Full Text Available Vacuum Electronic Devices (VEDs which are considered as the heart of a radar system, play an important role in their development. VEDs and radar systems supplement and promote each other. Some new trends in VEDs have been observed with advancements in the simulation tools for designing VEDs, new materials, new fabrication techniques. Recently, the performance of VEDs has greatly improved. In addition, new devices have been invented, which have laid the foundation for the developments of radar detection technology. This study introduces the recent development trends and research results of VEDs from microwave and millimeter wave devices and power modules, integrated VEDs, terahertz VEDs, and high power VEDs.

Vacuum Acceptance Tests for the UHV Room Temperature Vacuum System of the LHC during LS1

CERN Document Server

Cattenoz, G; Bregliozzi, G; Calegari, D; Gallagher, J; Marraffa, A; Chiggiato, P

2014-01-01

During the CERN Large Hadron Collider (LHC) first long shut down (LS1), a large number of vacuum tests are carried out on consolidated or newly fabricated devices. In such a way, the vacuum compatibility is assessed before installation in the UHV system of the LHC. According to the equipment’s nature, the vacuum acceptance tests consist in functional checks, leak test, outgassing rate measurements, evaluation of contaminants by Residual Gas Analysis (RGA), pumping speed measurements and qualification of the H2 sticking probability of Non-Evaporable-Getter (NEG) coating. In this paper, the methods used for the tests and the acceptance criteria are described. A summary of the measured vacuum characteristics for the tested components is also given.

CURVED WALLS: GRAIN GROWTH, SETTLING, AND COMPOSITION PATTERNS IN T TAURI DISK DUST SUBLIMATION FRONTS

International Nuclear Information System (INIS)

McClure, M. K.; Calvet, N.; Hartmann, L.; Ingleby, L.; D'Alessio, P.; Espaillat, C.; Sargent, B.; Watson, D. M.; Hernández, J.

2013-01-01

The dust sublimation walls of disks around T Tauri stars represent a directly observable cross-section through the disk atmosphere and midplane. Their emission properties can probe the grain size distribution and composition of the innermost regions of the disk, where terrestrial planets form. Here we calculate the inner dust sublimation wall properties for four classical T Tauri stars with a narrow range of spectral types and inclination angles and a wide range of mass accretion rates to determine the extent to which the walls are radially curved. Best fits to the near- and mid-IR excesses are found for curved, two-layer walls in which the lower layer contains larger, hotter, amorphous pyroxene grains with Mg/(Mg+Fe) = 0.6 and the upper layer contains submicron, cooler, mixed amorphous olivine and forsterite grains. As the mass accretion rates decrease from 10 –8 to 10 –10 M ☉ yr –1 , the maximum grain size in the lower layer decreases from ∼3 to 0.5 μm. We attribute this to a decrease in fragmentation and turbulent support for micron-sized grains with decreasing viscous heating. The atmosphere of these disks is depleted of dust with dust-gas mass ratios 1 × 10 –4 of the interstellar medium (ISM) value, while the midplane is enhanced to eight times the ISM value. For all accretion rates, the wall contributes at least half of the flux in the optically thin 10 μm silicate feature. Finally, we find evidence for an iron gradient in the disk, suggestive of that found in our solar system

CURVED WALLS: GRAIN GROWTH, SETTLING, AND COMPOSITION PATTERNS IN T TAURI DISK DUST SUBLIMATION FRONTS

Energy Technology Data Exchange (ETDEWEB)

McClure, M. K.; Calvet, N.; Hartmann, L.; Ingleby, L. [Department of Astronomy, The University of Michigan, 500 Church Street, 830 Dennison Building., Ann Arbor, MI 48109 (United States); D' Alessio, P. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, 58089 Morelia, Michoacán (Mexico); Espaillat, C. [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sargent, B. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Watson, D. M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Hernández, J., E-mail: melisma@umich.edu, E-mail: ncalvet@umich.edu, E-mail: lhartm@umich.edu, E-mail: lingleby@umich.edu, E-mail: p.dalessio@astrosmo.unam.mx, E-mail: cespaillat@cfa.harvard.edu, E-mail: baspci@rit.edu, E-mail: dmw@pas.rochester.edu, E-mail: hernandj@cida.ve [Centro de Investigaciones de Astronomía (CIDA), Mérida 5101-A (Venezuela, Bolivarian Republic of)

2013-10-01

The dust sublimation walls of disks around T Tauri stars represent a directly observable cross-section through the disk atmosphere and midplane. Their emission properties can probe the grain size distribution and composition of the innermost regions of the disk, where terrestrial planets form. Here we calculate the inner dust sublimation wall properties for four classical T Tauri stars with a narrow range of spectral types and inclination angles and a wide range of mass accretion rates to determine the extent to which the walls are radially curved. Best fits to the near- and mid-IR excesses are found for curved, two-layer walls in which the lower layer contains larger, hotter, amorphous pyroxene grains with Mg/(Mg+Fe) = 0.6 and the upper layer contains submicron, cooler, mixed amorphous olivine and forsterite grains. As the mass accretion rates decrease from 10{sup –8} to 10{sup –10} M{sub ☉} yr{sup –1}, the maximum grain size in the lower layer decreases from ∼3 to 0.5 μm. We attribute this to a decrease in fragmentation and turbulent support for micron-sized grains with decreasing viscous heating. The atmosphere of these disks is depleted of dust with dust-gas mass ratios 1 × 10{sup –4} of the interstellar medium (ISM) value, while the midplane is enhanced to eight times the ISM value. For all accretion rates, the wall contributes at least half of the flux in the optically thin 10 μm silicate feature. Finally, we find evidence for an iron gradient in the disk, suggestive of that found in our solar system.

Vacuum anti-shielding of monopoles

International Nuclear Information System (INIS)

Goebel, D.J.

1984-01-01

This chapter examines the difficulties in calculating the vacuum polarization, or magnetization, induced in the vacuum by a monopole. The usual Lagrangian formalism and consequent Feynman rules do not apply. Another problem is that the interaction strength between the monopole and a charge is not small (unless it vanishes exactly) because it is quantized to half integer values. Perturbation theory is therefore not applicable. The discussed problems are solved by using the old fashioned method of calculating a vacuum expectation value as a sum over single particle modes

High current vacuum closing switch

International Nuclear Information System (INIS)

Dolgachev, G.I.; Maslennikov, D.D.; Romanov, A.S.; Ushakov, A.G.

2005-01-01

The paper proposes a powerful pulsed closing vacuum switch for high current commutation consisting of series of the vacuum diodes with near 1 mm gaps having closing time determined by the gaps shortening with the near-electrode plasmas [ru

CaE-T zeolite - a new effective adsorber for vacuum technique

International Nuclear Information System (INIS)

Skvazyvaev, V.E.; Khvoshchev, S.S.; Zhdanov, S.P.

1975-01-01

Adsorption of air at low pressures on type E zeolites was studied as a function of their composition and dehydration regime. It was shown that zeolite CaE-T has a greatly increased sorption capacity for air at low pressures and that this is more than 3 times that of industrial zeolites currently used in vacuum technology. Mass-spectrometer studies were made of the gas phase over zeolites type E and A after adsorption of air at pressures from 10 -8 to 10 -5 mm Hg at liquid nitrogen temperatures under conditions approximating equilibrium. It was shown that zeolite CaE-T has a high adsorption capacity for Ar, O 2 , and H 2 . Adsorption of H 2 and Ar by zeolites of different structural types at low pressures was studied. It was shown that zeolite CaE-T has a significantly higher adsorption capacity for hydrogen and argon than all industrial zeolites

Study of a pressure measurement method using laser ionization for extremely-high vacuum

International Nuclear Information System (INIS)

Kokubun, Kiyohide

1991-01-01

A method of measuring pressures in the range of extremely-high vacuum (XHV) using the laser ionization has been studied. For this purpose, nonresonant multiphoton ionization of various kinds of gases has been studied, and highly-sensitive ion-detection systems and an extremely-high vacuum equipment were fabricated. These results are presented in detail. Two ion-detection systems were fabricated and tested: the one is based on the pulse-counting method, and the other utilizes the image-processing technique. The former is superior in detecting a few ions or less. The latter was processing technique. The former is superior in detecting a few ions or less. The latter was verified to able to count accurately the number of ions in the range of a few to several hundreds. To obtain the information on residual gases and test our pressure measurement system, an extremely-high vacuum system was fabricated in our own fashion, attained a pressure lower than 1 x 10 -10 Pa, measured with an extractor gauge. The outgassing rate of this vacuum vessel was measured to be 7.8 x 10 -11 Pa·m 3 /s·m 2 . The surface structures and the surface compositions of the raw material, the machined material, and the machined-and-outgased material were studied by SEM and AES. Besides, the pumping characteristics and the residual gases of the XHV system were investigated in detail at each pumping stage. On the course of these studies, the method of pressure measurement using the laser-ionization has been verified to be very effective for measuring pressures in XHV. (J.P.N.)

Analyses of hypothetical nuclear criticality excursions in 10- and 20-MW freezer/sublimer vessels

International Nuclear Information System (INIS)

Haught, C.F.; Jordan, W.C.; Basoglu, B.; Dodds, H.L.; Wilkinson, A.D.

1995-01-01

A theoretical model is used to predict the consequences of a postulated hypothetical nuclear criticality excursion in a freezer/sublimer (F/S). Previous work has shown that an intrusion of water into a F/S may result in a critical configuration. A first attempt is made to model the neutronic and thermal-hydraulic phenomena occurring during a criticality excursion involving both uranium hexafluoride (UF 6 ) and uranyl fluoride (UO 2 F 2 ) solution, which is present in the F/S during upset conditions. The model employs point neutronics coupled with simple thermal hydraulics. Reactivity feedback from changes in the properties of the system are included in the model. The excursion is studied in a 10-MW F/S with an initial load of 3,500 kg of 5% weight enriched UF 6 and in a 20-MW F/S with an initial load of 6,800 kg of 2% weight enriched UF 6 . The magnitude of the fission release determined in this work is 5.93 x 10 18 fissions in the 10-MW F/S and 4.21 x 10 18 fissions in the 20-MW F/S. In order to demonstrate the reliability of the techniques used in this work, a limited validation study was conducted by comparing the fission release and peak fission rate determined by this work with experimental results for a limited number of experiments. The agreement between calculations and experiments in the validation study is considered to be satisfactory. The calculational results for the hypothetical accidents in the two F/S vessels appear reasonable

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

Energy Technology Data Exchange (ETDEWEB)

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

1992-03-15

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

Experimental and computational study of the molecular energetics of the monoiodoanisole isomers

International Nuclear Information System (INIS)

Lobo Ferreira, Ana I.M.C.; Ribeiro da Silva, Manuel A.V.

2012-01-01

Highlights: ► Combustion calorimetry was used to determine Δ f H m ∘ (l, cr) of the monoiodoanisol isomers. ► Vapor pressures as function of the temperature were determined for 4-iodoanisol by the Knudsen mass-loss effusion technique. ► Enthalpies of vaporization of 2- and 3-iodoanisol were determined by Calvet microcalorimetry. ► Gas-phase Δ f H m ∘ of the studied compounds have been derived. - Abstract: The standard (p° = 0.1 MPa) molar enthalpies of formation, in the condensed phase, of the three monoiodoanisoles, were derived from the respective enthalpies of combustion, measured by rotating-bomb combustion calorimetry. Their enthalpies of sublimation/vaporization, at T = 298.15 K, were obtained by Calvet microcalorimetry using the high-temperature vacuum sublimation technique. Moreover the standard molar enthalpy, entropy and Gibbs energy of sublimation, at T = 298.15 K, of 4-iodoanisole were derived from the Knudsen mass-loss effusion technique. Combining the former sets of experimental results, the standard molar enthalpies of formation in the gas-phase, at T = 298.15 K, of 2-, 3- and 4-iodoanisole were derived, respectively, as: (15.1 ± 2.1) kJ · mol −1 ; (11.8 ± 2.2) kJ · mol −1 , and (12.4 ± 1.6) kJ · mol −1 . The experimental values of the gas-phase enthalpies of formation of each iodoanisole were also estimated by means of the empirical scheme developed by Cox and by density functional theory calculations employing the B3LYP/6-311++G(d,p) approach. Estimated values are in excellent agreement with the reported experimental ones derived in the present paper.

Development and Characterization of Mouth Dissolving Tablet of Zolmitriptan

Directory of Open Access Journals (Sweden)

Sudarshan Singh

2012-05-01

Full Text Available Objective: To formulate and Characterize Mouth Dissolving Tablet of Zolmitriptan to produce the intended benefits. Methods: Tablets were prepared using a direct compression method employing superdisintegrants such as Kyron T-314, Crospovidone, Croscarmellose Sodium, and Sodium Starch Glycolate. Tablets of Zolmitriptan prepared using Kyron T-314 exhibited the least friability and disintegration time 35 seconds. To decrease the disintegration time further, a sublimation technique was used along with the superdisintegrants for the preparation of Mouth Dissolving Tablet (MDTs. The addition of camphor as a subliming agent lowered the disintegration time 10 seconds further, but the percent friability was increased. A 32 full factorial design was employed to study the joint influence of the amount of superdisintegrant (Kyron T-314 and the amount of sublimating agent (Camphor on the percent of friability and the disintegration time. Results: The results of multiple linear regression analysis revealed that an effective MDT of Zolmitriptan requires higher percentages of Kyron T-314 and camphor should be used. The approach using the optimization technique helped to produce a detailed understanding effect of formulation parameters. An optimized formulation was found to have good hardness, wetting time, disintegration time. Release kinetic model study indicated that all the formulations follow zero order kinetics. It also indicated that batch F1, F2, F5 and F8 releases the drug at constant rate as well as fast rate as per the Weibull model which was also confirmed by HixsonCrowell model. Stability studies indicated that there are no significant changes in hardness, Percentage friability, drug content and in-vitro disintegration time and cumulative percentage drug release. Conclusions: Thus, it was concluded that by adopting a systematic formulation approach, Zolmitriptan Mouth dissolving tablet could be formulated using superdisintegrants in combination with

Vacuum considerations summary

International Nuclear Information System (INIS)

1977-01-01

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

Vacuum systems for the ILC helical undulator

CERN Document Server

Malyshev, O B; Clarke, J A; Bailey, I R; Dainton, J B; Malysheva, L I; Barber, D P; Cooke, P; Baynham, E; Bradshaw, T; Brummitt, A; Carr, S; Ivanyushenkov, Y; Rochford, J; Moortgat-Pick, G A

2007-01-01

The International Linear Collider (ILC) positron source uses a helical undulator to generate polarized photons of ∼10MeV∼10MeV at the first harmonic. Unlike many undulators used in synchrotron radiation sources, the ILC helical undulator vacuum chamber will be bombarded by photons, generated by the undulator, with energies mostly below that of the first harmonic. Achieving the vacuum specification of ∼100nTorr∼100nTorr in a narrow chamber of 4–6mm4–6mm inner diameter, with a long length of 100–200m100–200m, makes the design of the vacuum system challenging. This article describes the vacuum specifications and calculations of the flux and energy of photons irradiating the undulator vacuum chamber and considers possible vacuum system design solutions for two cases: cryogenic and room temperature.

Pumping characteristics of sputter ion pump (SIP) and titanium sublimation pump (TSP) combination

International Nuclear Information System (INIS)

Ratnakala, K.C.; Patel, R.J.; Bhavsar, S.T.; Pandiyar, M.L.; Ramamurthi, S.S.

1995-01-01

For achieving hydrocarbon free, clean ultra high vacuum, SIP-TSP combination is one of the ideal choice for pumping. For the SRS facility in Centre for Advanced Technology (CAT), we are utilising this combination, enmass. For this purpose, two modules of these combination set-ups are assembled, one with the TSP as an integral part of SIP and the other, with TSP as a separate pump mounted on the top of SIP. The pump bodies were vacuum degassed at 700 degC at 10 -5 mbar for 3 hrs. An ultimate vacuum of 3 x 10 -11 mbar was achieved, after a bake-out at 250 degC for 4 hrs, followed by continuous SIP pumping for 48 hrs, with two TSP flashing at approximately 10 hrs interval. The pump-down patterns as well as the pressure-rise patterns are studied. (author). 2 refs., 5 figs

Re-circulating linac vacuum system

International Nuclear Information System (INIS)

Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

2003-01-01

The vacuum system for a proposed 2.5 GeV, 10ΜA recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10ΜA average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing

Calculation of the Hadronic Vacuum Polarization Disconnected Contribution to the Muon Anomalous Magnetic Moment.

Science.gov (United States)

Blum, T; Boyle, P A; Izubuchi, T; Jin, L; Jüttner, A; Lehner, C; Maltman, K; Marinkovic, M; Portelli, A; Spraggs, M

2016-06-10

We report the first lattice QCD calculation of the hadronic vacuum polarization (HVP) disconnected contribution to the muon anomalous magnetic moment at physical pion mass. The calculation uses a refined noise-reduction technique that enables the control of statistical uncertainties at the desired level with modest computational effort. Measurements were performed on the 48^{3}×96 physical-pion-mass lattice generated by the RBC and UKQCD Collaborations. We find the leading-order hadronic vacuum polarization a_{μ}^{HVP(LO)disc}=-9.6(3.3)(2.3)×10^{-10}, where the first error is statistical and the second systematic.

Calculation of the Hadronic Vacuum Polarization Disconnected Contribution to the Muon Anomalous Magnetic Moment

Science.gov (United States)

Blum, T.; Boyle, P. A.; Izubuchi, T.; Jin, L.; Jüttner, A.; Lehner, C.; Maltman, K.; Marinkovic, M.; Portelli, A.; Spraggs, M.; Rbc; Ukqcd Collaborations

2016-06-01

We report the first lattice QCD calculation of the hadronic vacuum polarization (HVP) disconnected contribution to the muon anomalous magnetic moment at physical pion mass. The calculation uses a refined noise-reduction technique that enables the control of statistical uncertainties at the desired level with modest computational effort. Measurements were performed on the 483×96 physical-pion-mass lattice generated by the RBC and UKQCD Collaborations. We find the leading-order hadronic vacuum polarization aμHVP (LO )disc=-9.6 (3.3 )(2.3 )×10-10 , where the first error is statistical and the second systematic.

Paths of the Sublime: Alain de Botton’s The Art of Travel

Directory of Open Access Journals (Sweden)

M.C.C. Mendes

2015-05-01

Full Text Available Bearing in mind the central place of literary, academic, and religious tourism in Cultural Studies and in Alain de Botton’s The Art of Travel (2002, the paper seeks: 1 to identify some remarkable travels of famous writers – the British Wordsworth; the French Karl-Joris Huysmans, Gustave Flaubert, and Charles Baudelaire; 2 to show that in the analysis of such authors’ itineraries (from Europe to the East, there is a search for cultural roots, a mapping of spaces and people, and a deconstruction of labels often related to the Other; 3 to point out that the tourist is also a storyteller, a protagonist, and a creator of fictional worlds; 4 to bring together literary tourism and artistic tourism, through the identification of allusions to other cultural events (painting, music, and architecture; 5 to characterize tourism as a literary and aesthetic experience of the Sublime.

DC photogun vacuum characterization through photocathode lifetime studies

International Nuclear Information System (INIS)

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

2007-01-01

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

Schlenk Techniques for Anionic Polymerization

KAUST Repository

Ratkanthwar, Kedar; Zhao, Junpeng; Zhang, Hefeng; Hadjichristidis, Nikolaos; Mays, Jimmy

2015-01-01

Anionic polymerization-high vacuum techniques (HVTs) are doubtlessly the most prominent and reliable experimental tools to prepare polymer samples with well-defined and, in many cases, complex macromolecular architectures. Due to the high demands

The electrocatalytic oxidation of carbohydrates at a nickel/carbon paper electrode fabricated by the filtered cathodic vacuum arc technique

International Nuclear Information System (INIS)

Fu, Yingyi; Wang, Tong; Su, Wen; Yu, Yanan; Hu, Jingbo

2015-01-01

The direct electrochemical behaviour of carbohydrates at a nickel/carbon paper electrode with a novel fabrication method is investigated. The investigation is used for verification the feasibility of using monosaccharides and disaccharides in the application of fuel cell. The selected monosaccharides are glucose, fructose and galactose; the disaccharides are sucrose, maltose and lactose. The modified nickel/carbon paper electrode was prepared using a filtered cathodic vacuum arc technique. The morphology image of the nickel thin film on the carbon paper surface was characterized by scanning electron microscopy (SEM). The existence of nickel was verified by X-ray photoelectron spectroscopy (XPS). The contact angle measurement was also used to characterize the modified electrode. Cyclic voltammetry (CV) was employed to evaluate the electrochemical behaviour of monosaccharides and disaccharides in an alkaline aqueous solution. The modified electrode exhibits good electrocatalytic activities towards carbohydrates. In addition, the stability of the nickel/carbon paper electrode with six sugars was also investigated. The good catalytic effects of the nickel/carbon paper electrode allow for the use of carbohydrates as fuels in fuel cell applications

Flexural Strength of Banana Fibre Reinforced Epoxy Composites Produced through Vacuum Infusion and Hand Lay-Up Techniques - A Comparative Study

Directory of Open Access Journals (Sweden)

Mohamed Rahman

2017-07-01

Full Text Available Natural fiber such as kenaf, sisal, pineapple leaf and banana are growing popular nowadays due to its favor over traditional glass fiber and inorganic material. It is a renewable resources and abundantly available in the market. The composites made of natural fiber are economical, lightweight and environmental friendly. This study works on producing a composite based on the Banana fiber reinforced epoxy resin by using the method of Vacuum Infusion and Hand Lay-up. Banana fiber will be treated with Sodium Hydroxide (NaOH and water solution for 1 hour and then dried in the oven for 24 hours at 100°C. The composite will be produce based on different fiber volume fraction of 20% and 40% as well as different fiber length of 127mm, and 63mm. In Vacuum Infusion process, a mold made of aluminium have been manufactured according to the size of specimens of 127mm x 12.7mm x 3.2mm in dimension will be used in the preparation of specimens. The specimens of different volume fraction and fiber length produced by vacuum infusion and hand lay-up method will be mechanically tested through flexural test. The highest flexural strength is the specimen made by vacuum infusion process with 40% volume fraction and 63mm fiber length, which is 136.27MPa while for the hand lay-up process, the highest flexural strength is 80.71 with 40% volume fraction and 63mm fiber length.

Troubleshooting vacuum systems steam turbine surface condensers and refinery vacuum towers

CERN Document Server

Lieberman, Norman P

2012-01-01

Vacuum systems are in wide spread use in the petrochemical plants, petroleum refineries and power generation plants. The existing texts on this subject are theoretical in nature and only deal with how the equipment functions when in good mechanical conditions, from the viewpoint of the equipment vendor.  In this much-anticipated volume, one of the most well-respected and prolific process engineers in the world takes on troubleshooting vacuum systems, and especially steam ejectors, an extremely complex and difficult subject that greatly effects the profitability of the majority of the world'

Vacuum arc anode phenomena

International Nuclear Information System (INIS)

Miller, H.C.

1976-01-01

A brief review of anode phenomena in vacuum arcs is presented. Discussed in succession are: the transition of the arc into the anode spot mode; the temperature of the anode before, during and after the anode spot forms; and anode ions. Characteristically the anode spot has a temperature of the order of the atmospheric boiling point of the anode material and is a copious source of vapor and energetic ions. The dominant mechanism controlling the transition of the vacuum arc into the anode spot mode appears to depend upon the electrode geometry, the electrode material, and the current waveform of the particular vacuum arc being considered. Either magnetic constriction in the gap plasma or gross anode melting can trigger the transition; indeed, a combination of the two is a common cause of anode spot formation

Low energy electron diffraction (LEED) and sum frequency generation (SFG) vibrational spectroscopy studies of solid-vacuum, solid-air and solid-liquid interfaces

Energy Technology Data Exchange (ETDEWEB)

Hoffer, Saskia [Univ. of California, Berkeley, CA (United States)

2002-01-01

Electron based surface probing techniques can provide detailed information about surface structure or chemical composition in vacuum environments. The development of new surface techniques has made possible in situ molecular level studies of solid-gas interfaces and more recently, solid-liquid interfaces. The aim of this dissertation is two-fold. First, by using novel sample preparation, Low Energy Electron Diffraction (LEED) and other traditional ultra high vacuum (UHV) techniques are shown to provide new information on the insulator/vacuum interface. The surface structure of the classic insulator NaCl has been determined using these methods. Second, using sum frequency generation (SFG) surface specific vibrational spectroscopy studies were performed on both the biopolymer/air and electrode/electrolyte interfaces. The surface structure and composition of polyetherurethane-silicone copolymers were determined in air using SFG, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). SFG studies of the electrode (platinum, gold and copper)/electrolyte interface were performed as a function of applied potential in an electrochemical cell.

Resistor cooling in a vacuum

International Nuclear Information System (INIS)

Crittenden, R.; Krider, J.

1987-01-01

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

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

Science.gov (United States)

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

2015-12-01

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.

Determination of molar enthalpy of sublimation in case of orotic acid as obtained from experimental and computational data

Science.gov (United States)

Marochkin, Ilya I.; Altova, Ekaterina P.; Chilingarov, Norbert S.; Vilkova, Anna L.; Shishkov, Igor F.

2018-03-01

Saturated vapor pressure, ln(p/Pa) = (-21316 ± 511)/(T/K)+(41.64 ± 0.11), and enthalpy of sublimation of orotic acid, Δsub Hm0 (Tm) = 177 ± 4 kJ/mol, were determined by means of Knudsen effusion mass spectrometry in the temperature range of 423÷493 K. The computational approaches supported the experimental results reported. The theoretical estimation of the gas-phase enthalpy of formation for orotic acid was done with different working reactions used.

Topology of classical vacuum space-time

International Nuclear Information System (INIS)

Cho, Y.M.

2007-04-01

We present a topological classification of classical vacuum space-time. Assuming the 3-dimensional space allows a global chart, we show that the static vacuum space-time of Einstein's theory can be classified by the knot topology π 3 (S 3 ) = π 3 (S 2 ). Viewing Einstein's theory as a gauge theory of Lorentz group and identifying the gravitational connection as the gauge potential of Lorentz group, we construct all possible vacuum gravitational connections which give a vanishing curvature tensor. With this we show that the vacuum connection has the knot topology, the same topology which describes the multiple vacua of SU(2) gauge theory. We discuss the physical implications of our result in quantum gravity. (author)

Gravitational collapse and the vacuum energy

International Nuclear Information System (INIS)

Campos, M

2014-01-01

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.