WorldWideScience

Sample records for cloud chambers

  1. Cloud Chamber

    DEFF Research Database (Denmark)

    Gfader, Verina

    Cloud Chamber takes its roots in a performance project, titled The Guests 做东, devised by Verina Gfader for the 11th Shanghai Biennale, ‘Why Not Ask Again: Arguments, Counter-arguments, and Stories’. Departing from the inclusion of the biennale audience to write a future folk tale, Cloud Chamber......: fiction and translation and translation through time; post literacy; world picturing-world typing; and cartographic entanglements and expressions of subjectivity; through the lens a social imaginary of worlding or cosmological quest. Art at its core? Contributions by Nikos Papastergiadis, Rebecca Carson...

  2. Peltier-based cloud chamber

    Science.gov (United States)

    Nar, Sevda Yeliz; Cakir, Altan

    2018-02-01

    Particles produced by nuclear decay, cosmic radiation and reactions can be identified through various methods. One of these methods that has been effective in the last century is the cloud chamber. The chamber makes visible cosmic particles that we are exposed to radiation per second. Diffusion cloud chamber is a kind of cloud chamber that is cooled by dry ice. This traditional model has some application difficulties. In this work, Peltier-based cloud chamber cooled by thermoelectric modules is studied. The new model provided uniformly cooled base of the chamber, moreover, it has longer lifetime than the traditional chamber in terms of observation time. This gain has reduced the costs which spent each time for cosmic particle observation. The chamber is an easy-to-use system according to traditional diffusion cloud chamber. The new model is portable, easier to make, and can be used in the nuclear physics experiments. In addition, it would be very useful to observe Muons which are the direct evidence for Lorentz contraction and time expansion predicted by Einsteins special relativity principle.

  3. Experimental project - Cloud chamber

    International Nuclear Information System (INIS)

    Nour, Elena; Quinchard, Gregory; Soudon, Paul

    2015-01-01

    This document reports an academic experimental project dealing with the general concepts of radioactivity and their application to the cloud room experiment. The author first recalls the history of the design and development of a cloud room, and some definitions and characteristics of cosmic radiation, and proposes a description of the principle and physics of a cloud room. The second part is a theoretical one, and addresses the involved particles, the origins of electrons, and issues related to the transfer of energy (Bremsstrahlung effect, Bragg peak). The third part reports the experimental work with the assessment of a cloud droplet radius, the identification of a trace for each particle (alphas and electrons), and the study of the magnetic field deviation

  4. Simple Cloud Chambers Using Gel Ice Packs

    Science.gov (United States)

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  5. Cloud chamber photographs of the cosmic radiation

    CERN Document Server

    Rochester, George Dixon

    1952-01-01

    Cloud Chamber Photographs of the Cosmic Radiation focuses on cloud chamber and photographic emulsion wherein the tracks of individual subatomic particles of high energy are studied. The publication first offers information on the technical features of operation and electrons and cascade showers. Discussions focus on the relationship in time and space of counter-controlled tracks; techniques of internal control of the cloud chamber; cascade processes with artificially-produced electrons and photons; and nuclear interaction associated with an extensive shower. The manuscript then elaborates on

  6. Cloud chamber development for didactic use

    International Nuclear Information System (INIS)

    Straube, B; Carrillo, M; Mangussi J

    2012-01-01

    The goal of this project was the design and construction of an Expansion Cloud Chamber from daily use material in order to make visible during a lesson, the trajectories of particles emitted by a radioactive material (author)

  7. How to build a cloud chamber?

    International Nuclear Information System (INIS)

    Mariaud, C.

    2012-01-01

    The cloud chamber had its heyday in the first half of last century and allowed the discovery of new particles such as the anti-electron, the muon and the neutral and the charged kaon. The bubble chamber replaced it in the mid fifties. This article recalls the principle of the cloud chamber and shows, in a detailed way, how to proceed to build one with on-the-shelf materials. This design is based on the use of isopropanol whose liquefaction through the form of droplets materializes the track of the particle and on the use of combined Peltier cells (instead of CO 2 snow) to cool the chamber. This cloud chamber has been successfully used in schools to observe particles mainly electrons, alphas and muons generated by cosmic rays. (A.C.)

  8. Developing Cloud Chambers with High School Students

    Science.gov (United States)

    Ishizuka, Ryo; Tan, Nobuaki; Sato, Shoma; Zeze, Syoji

    The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry-ice-free cloud chamber using salt and ice (or snow). Technical details of the chamber are described. We also argue how the project have affected student's cognition, motivation, academic skills and behavior. The research project has taken steps of professional researchers, i.e., in planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we have learnt that such style of scientific activity is very effective in promoting student's motivation for learning science.

  9. Temperature uniformity in the CERN CLOUD chamber

    Directory of Open Access Journals (Sweden)

    A. Dias

    2017-12-01

    Full Text Available The CLOUD (Cosmics Leaving OUtdoor Droplets experiment at CERN (European Council for Nuclear Research investigates the nucleation and growth of aerosol particles under atmospheric conditions and their activation into cloud droplets. A key feature of the CLOUD experiment is precise control of the experimental parameters. Temperature uniformity and stability in the chamber are important since many of the processes under study are sensitive to temperature and also to contaminants that can be released from the stainless steel walls by upward temperature fluctuations. The air enclosed within the 26 m3 CLOUD chamber is equipped with several arrays (strings of high precision, fast-response thermometers to measure its temperature. Here we present a study of the air temperature uniformity inside the CLOUD chamber under various experimental conditions. Measurements were performed under calibration conditions and run conditions, which are distinguished by the flow rate of fresh air and trace gases entering the chamber at 20 and up to 210 L min−1, respectively. During steady-state calibration runs between −70 and +20 °C, the air temperature uniformity is better than ±0.06 °C in the radial direction and ±0.1 °C in the vertical direction. Larger non-uniformities are present during experimental runs, depending on the temperature control of the make-up air and trace gases (since some trace gases require elevated temperatures until injection into the chamber. The temperature stability is ±0.04 °C over periods of several hours during either calibration or steady-state run conditions. During rapid adiabatic expansions to activate cloud droplets and ice particles, the chamber walls are up to 10 °C warmer than the enclosed air. This results in temperature differences of ±1.5 °C in the vertical direction and ±1 °C in the horizontal direction, while the air returns to its equilibrium temperature with a time constant of about 200 s.

  10. Cloud chamber researches in nuclear physics and cosmic radiation

    International Nuclear Information System (INIS)

    Blackett, P.

    1984-01-01

    An extract from Blackett's Nobel Prize speech of 1948, this recounts the work done by the author on particle tracks in a Wilson cloud chamber in 1932 at the Cavendish Laboratory, Cambridge. In particular he studied the energetic particles in cosmic rays using a cloud chamber and camera. The improvements to the equipment are recounted and photographs of cosmic ray showers taken with it are shown. (UK)

  11. The cloud chamber. A wonderful instrument for discoveries

    International Nuclear Information System (INIS)

    Fadel, Kamil

    2012-01-01

    The author proposes an overview of the various applications and discoveries based on the use of the cloud chamber or Wilson chamber: blood flow rate measurements, investigation of alpha radiation (interaction of an alpha particle with gas atoms), investigation of beta radioactivity with the evidence of the existence of the neutrino, confirmation of a relativistic effect, discovery of the neutron in the 1930's, uranium fission, evidence of the cosmic origin of a ionizing radiation in the 1930's. The author briefly evokes the technological evolutions of these cloud chambers

  12. Simple structure diffusion cloud chamber for educational purpose

    International Nuclear Information System (INIS)

    Hrehuss, Gy.; Molnar, B.

    1982-01-01

    A simple structure diffusion cloud chamber was designed and built with educational aim. The source of alpha particles is Am-241 radioisotope smeared on steel foil, the source of vapor is a felt disc saturated with methanol. Five minutes after covering the chamber the system achieves the thermodynamic equilibrium and alpha particle tracks of 5 cm length become visible in the centre of the chamber. Life-time of a track is about 0.5-1 second, the frequency is 2-3 tracks/s. The presented diffusion chamber can be built simply and easily, using cheap common materials and components. (D.Gy.)

  13. Beam Measurements of a CLOUD (Cosmics Leaving OUtdoor Droplets) Chamber

    CERN Document Server

    Kirkby, Jasper

    2001-01-01

    A striking correlation has recently been observed between global cloud cover and the flux of incident cosmic rays. The effect of natural variations in the cosmic ray flux is large, causing estimated changes in the Earth's energy radiation balance that are comparable to those attributed to greenhouse gases from the burning of fossil fuels since the Industrial Revolution. However a direct link between cosmic rays and cloud formation has not been unambiguously established. We therefore propose to experimentally measure cloud (water droplet) formation under controlled conditions in a test beam at CERN with a CLOUD chamber, duplicating the conditions prevailing in the troposphere. These data, which have never been previously obtained, will allow a detailed understanding of the possible effects of cosmic rays on clouds and confirm, or otherwise, a direct link between cosmic rays, global cloud cover and the Earth's climate. The measurements will, in turn, allow more reliable calculations to be made of the residual e...

  14. Development of Cloud Chamber by Using Peltier Device

    International Nuclear Information System (INIS)

    Woo, Jong Kwan; Kwon, Jin Young; Park, Sang Tae

    2011-01-01

    In this research, we developed the newly cloud chamber apparatus by using Peltier device to apply nuclear physics experiment in high school or university. We observed the cosmic rays track by using the developed apparatus and a camcorder. And we compared and analyzed the acquired data. From the results, we acquired the following conclusions and suggestions : First, it is very difficult to observe the cosmic rays track in the typical cloud chamber because of the low frequency of it. But in the newly developed cloud chamber we can observe easily the cosmic rays track owing to the high frequency of it. Second, when we do the experiment with the newly developed apparatus, we found that the cosmic rays track happens well under the condition that the temperature of the upper place of cooling plate must be below 5 degree Celsius with more than isopropanol 1.04X10 -5 ml.mm -3 . Third, the newly developed apparatus will be improved to have better precision by controlling the temperature of cooling plate in the cloud chamber by current intensity. Therefore we think that it is very useful to use the newly developed apparatus in the nuclear physics experiment in high school or university.

  15. Development of Cloud Chamber by Using Peltier Device

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Jong Kwan [Jae Hyun High School, Seoul (Korea, Republic of); Kwon, Jin Young [Jeon Min High School, Daejeon (Korea, Republic of); Park, Sang Tae [Dept. of Physics Education, Kongju National University, Kongju (Korea, Republic of)

    2011-09-15

    In this research, we developed the newly cloud chamber apparatus by using Peltier device to apply nuclear physics experiment in high school or university. We observed the cosmic rays track by using the developed apparatus and a camcorder. And we compared and analyzed the acquired data. From the results, we acquired the following conclusions and suggestions : First, it is very difficult to observe the cosmic rays track in the typical cloud chamber because of the low frequency of it. But in the newly developed cloud chamber we can observe easily the cosmic rays track owing to the high frequency of it. Second, when we do the experiment with the newly developed apparatus, we found that the cosmic rays track happens well under the condition that the temperature of the upper place of cooling plate must be below 5 degree Celsius with more than isopropanol 1.04X10{sup -5}ml.mm{sup -3}. Third, the newly developed apparatus will be improved to have better precision by controlling the temperature of cooling plate in the cloud chamber by current intensity. Therefore we think that it is very useful to use the newly developed apparatus in the nuclear physics experiment in high school or university.

  16. Measurement of optical blurring in a turbulent cloud chamber

    Science.gov (United States)

    Packard, Corey D.; Ciochetto, David S.; Cantrell, Will H.; Roggemann, Michael C.; Shaw, Raymond A.

    2016-10-01

    Earth's atmosphere can significantly impact the propagation of electromagnetic radiation, degrading the performance of imaging systems. Deleterious effects of the atmosphere include turbulence, absorption and scattering by particulates. Turbulence leads to blurring, while absorption attenuates the energy that reaches imaging sensors. The optical properties of aerosols and clouds also impact radiation propagation via scattering, resulting in decorrelation from unscattered light. Models have been proposed for calculating a point spread function (PSF) for aerosol scattering, providing a method for simulating the contrast and spatial detail expected when imaging through atmospheres with significant aerosol optical depth. However, these synthetic images and their predicating theory would benefit from comparison with measurements in a controlled environment. Recently, Michigan Technological University (MTU) has designed a novel laboratory cloud chamber. This multiphase, turbulent "Pi Chamber" is capable of pressures down to 100 hPa and temperatures from -55 to +55°C. Additionally, humidity and aerosol concentrations are controllable. These boundary conditions can be combined to form and sustain clouds in an instrumented laboratory setting for measuring the impact of clouds on radiation propagation. This paper describes an experiment to generate mixing and expansion clouds in supersaturated conditions with salt aerosols, and an example of measured imagery viewed through the generated cloud is shown. Aerosol and cloud droplet distributions measured during the experiment are used to predict scattering PSF and MTF curves, and a methodology for validating existing theory is detailed. Measured atmospheric inputs will be used to simulate aerosol-induced image degradation for comparison with measured imagery taken through actual cloud conditions. The aerosol MTF will be experimentally calculated and compared to theoretical expressions. The key result of this study is the

  17. Simple Cloud Chambers Using a Freezing Mixture of Ice and Cooking Salt

    Science.gov (United States)

    Yoshinaga, Kyohei; Kubota, Miki; Kamata, Masahiro

    2015-01-01

    We have developed much simpler cloud chambers that use only ice and cooking salt instead of the dry ice or ice gel pack needed for the cloud chambers produced in our previous work. The observed alpha-ray particle tracks are as clear as those observed using our previous cloud chambers. The tracks can be observed continuously for about 20?min, and…

  18. Explosion-induced combustion of hydrocarbon clouds in a chamber

    International Nuclear Information System (INIS)

    Neuwald, P; Reichenbach, H; Kuhl, A L

    2001-01-01

    The interaction of the detonation of a solid HE-charge with a non-premixed cloud of hydro-carbon fuel in a chamber was studied in laboratory experiments. Soap bubbles filled with a flammable gas were subjected to the blast wave created by the detonation of PETN-charges (0.2 g < mass < 0.5 g). The dynamics of the combustion system were investigated by means of high-speed photography and measurement of the quasi-static chamber pressure

  19. Calculation of nondiffused proximity functions from cloud-chamber data

    International Nuclear Information System (INIS)

    Zaider, M.

    1987-01-01

    To a large extent the cloud chamber is an ideal microdosimetric device: by measuring the positions of ionizing events in charged-particle tracks one can generate - with a flexibility matched only by Monte-Carlo simulations-any microdosimetric quantity of interest, ranging from lineal energy spectra (in volumes of practically arbitrary shape and size) to proximity functions, that is, distributions of distances between energy transfer points in the track. Cloud-chamber data analyzed in such ways have been indeed reported for a variety of radiations. In view of these clear advantages it is certainly surprising that, within the microdosimetric community, only one group (at Harwell, UK) is actively involved in such work and that, furthermore, cloud-chamber results are used essentially only as a testing ground for Monte-Carlo calculations. It appears that this reluctance can be traced to the fact that the tracks are distorted by the diffusion of droplets during their growth. This diffusion - which is of the order of several nanometers (in unit-density material), although rather insignificant vis-a-vis conventional microdosimetry, can be a serious limitation in view of modern theories of radiation action which emphasize energy deposition events at the nanometer level. The purpose of this research activity is to show that, using a rather straight-forward mathematical procedure, one can unfold the effect of diffusion from proximity functions. Since the nondiffused proximity function can be used to calculate other microdosimetric quantities an important limitation of the cloud-chamber data can thus be avoided

  20. An example of radiation-education experiment using a new-type handy cloud chamber

    International Nuclear Information System (INIS)

    Kushita, Kouhei

    2005-01-01

    We have developed a new-type handy cloud chamber to overcome shortcomings in the conventional handy cloud chambers. The new-type handy cloud chamber has such advantages as: no dangerous parts or tools are used; can be assembled quickly; has a wider observation window; much less expensive, etc. We have also prepared a new text for this cloud-chamber kit to explain the basic theory of radiation and radioisotopes, which is divided into two levels for children and for adults. Using this new-type handy cloud chamber, we propose an example of an educational experiment on radiation and radioisotopes which can be carried out within one hour. (author)

  1. Corona discharge induced snow formation in a cloud chamber.

    Science.gov (United States)

    Ju, Jingjing; Wang, Tie-Jun; Li, Ruxin; Du, Shengzhe; Sun, Haiyi; Liu, Yonghong; Tian, Ye; Bai, Yafeng; Liu, Yaoxiang; Chen, Na; Wang, Jingwei; Wang, Cheng; Liu, Jiansheng; Chin, S L; Xu, Zhizhan

    2017-09-18

    Artificial rainmaking is in strong demand especially in arid regions. Traditional methods of seeding various Cloud Condensation Nuclei (CCN) into the clouds are costly and not environment friendly. Possible solutions based on ionization were proposed more than 100 years ago but there is still a lack of convincing verification or evidence. In this report, we demonstrated for the first time the condensation and precipitation (or snowfall) induced by a corona discharge inside a cloud chamber. Ionic wind was found to have played a more significant role than ions as extra CCN. In comparison with another newly emerging femtosecond laser filamentation ionization method, the snow precipitation induced by the corona discharge has about 4 orders of magnitude higher wall-plug efficiency under similar conditions.

  2. Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

    Science.gov (United States)

    Rosenfeld, Daniel; Zheng, Youtong; Hashimshoni, Eyal; Pöhlker, Mira L.; Jefferson, Anne; Pöhlker, Christopher; Yu, Xing; Zhu, Yannian; Liu, Guihua; Yue, Zhiguo; Fischman, Baruch; Li, Zhanqing; Giguzin, David; Goren, Tom; Artaxo, Paulo; Pöschl, Ulrich

    2016-01-01

    Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25° restricts the satellite coverage to ∼25% of the world area in a single day. PMID:26944081

  3. Cloud chamber experiments on the origin of ice crystal complexity in cirrus clouds

    Directory of Open Access Journals (Sweden)

    M. Schnaiter

    2016-04-01

    Full Text Available This study reports on the origin of small-scale ice crystal complexity and its influence on the angular light scattering properties of cirrus clouds. Cloud simulation experiments were conducted at the AIDA (Aerosol Interactions and Dynamics in the Atmosphere cloud chamber of the Karlsruhe Institute of Technology (KIT. A new experimental procedure was applied to grow and sublimate ice particles at defined super- and subsaturated ice conditions and for temperatures in the −40 to −60 °C range. The experiments were performed for ice clouds generated via homogeneous and heterogeneous initial nucleation. Small-scale ice crystal complexity was deduced from measurements of spatially resolved single particle light scattering patterns by the latest version of the Small Ice Detector (SID-3. It was found that a high crystal complexity dominates the microphysics of the simulated clouds and the degree of this complexity is dependent on the available water vapor during the crystal growth. Indications were found that the small-scale crystal complexity is influenced by unfrozen H2SO4 / H2O residuals in the case of homogeneous initial ice nucleation. Angular light scattering functions of the simulated ice clouds were measured by the two currently available airborne polar nephelometers: the polar nephelometer (PN probe of Laboratoire de Métérologie et Physique (LaMP and the Particle Habit Imaging and Polar Scattering (PHIPS-HALO probe of KIT. The measured scattering functions are featureless and flat in the side and backward scattering directions. It was found that these functions have a rather low sensitivity to the small-scale crystal complexity for ice clouds that were grown under typical atmospheric conditions. These results have implications for the microphysical properties of cirrus clouds and for the radiative transfer through these clouds.

  4. Characterisation of organic contaminants in the CLOUD chamber at CERN

    CERN Document Server

    Schnitzhofer, R; Breitenlechner, M; Jud, W; Heinritzi, M; Menezes, L-P; Duplissy, J; Guida, R; Haider, S; Kikby, J; Mathot, S; Minginette, P; Onnela, A; Walther, H; Wasem, A; Hansel, A; CLOUD Team

    2014-01-01

    The CLOUD experiment (Cosmics Leaving OUtdoor Droplets) investigates the nucleation of new particles and how this process is influenced by galactic cosmic rays in an electropolished, stainless-steel environmental chamber at CERN (European Organization for Nuclear Research). Since volatile organic compounds (VOCs) can act as precursor gases for nucleation and growth of particles, great efforts have been made to keep their unwanted background levels as low as possible and to quantify them. In order to be able to measure a great set of VOCs simultaneously in the low parts per trillion (pptv) range, proton-transfer-reaction mass spectrometry (PTR-MS) was used. Initially the total VOC background concentration strongly correlated with ozone in the chamber and ranged from 0.1 to 7 parts per billion (ppbv). Plastic used as sealing material in the ozone generator was found to be a major VOC source. Especially oxygen-containing VOCs were generated together with ozone. These parts were replaced by stainless steel after ...

  5. How to build a cloud chamber?; Comment realiser une chambre a bouillard?

    Energy Technology Data Exchange (ETDEWEB)

    Mariaud, C. [Lycee Rene Descartes, 37000 Tours (France)

    2012-01-15

    The cloud chamber had its heyday in the first half of last century and allowed the discovery of new particles such as the anti-electron, the muon and the neutral and the charged kaon. The bubble chamber replaced it in the mid fifties. This article recalls the principle of the cloud chamber and shows, in a detailed way, how to proceed to build one with on-the-shelf materials. This design is based on the use of isopropanol whose liquefaction through the form of droplets materializes the track of the particle and on the use of combined Peltier cells (instead of CO{sub 2} snow) to cool the chamber. This cloud chamber has been successfully used in schools to observe particles mainly electrons, alphas and muons generated by cosmic rays. (A.C.)

  6. Evaluation of tecniques for controlling UF6 release clouds in the GAT environmental chamber

    International Nuclear Information System (INIS)

    Lux, C.J.

    1982-01-01

    Studies designed to characterize the reaction between UF 6 and atmospheric moisture, evaluate environmental variables of UF 6 cloud formation and ultimate cloud fate, and UF 6 release cloud control procedure have been conducted in the 1200 cu. ft. GAT environmental chamber. In earlier chamber experiments, 30 separate UF 6 release tests indicated that variations of atmospheric conditions and sample sizes had no significant effect on UO 2 F 2 particle size distribution, release cloud formation, or cloud settling rates. During the past year, numerous procedures have been evaluated for accelerating UF 6 cloud knockdown in a series of 37 environmental chamber releases. Knockdown procedures included: coarse water spray; air jet; steam spray (electrostatically charged and uncharged); carbon dioxide; Freon-12; fine water mist (uncharged); boric acid mist (charged and uncharged); and an ionized dry air stream. UF 6 hydrolysis cloud settling rates monitored by a laser/powermeter densitometer, indicated the relative effectiveness of various cloud knockdown techniques. Electrostatically charged boric acid/water mist, and electrostatically ionized dry air were both found to be very effective, knocking down the UO 2 F 2 release cloud particles in two to five minutes. Work to adapt these knockdown techniques for use under field conditions is continuing, taking into account recovery of the released uranium as well as nuclear criticality constraints

  7. Laser-filamentation-induced condensation and snow formation in a cloud chamber.

    Science.gov (United States)

    Ju, Jingjing; Liu, Jiansheng; Wang, Cheng; Sun, Haiyi; Wang, Wentao; Ge, Xiaochun; Li, Chuang; Chin, See Leang; Li, Ruxin; Xu, Zhizhan

    2012-04-01

    Using 1 kHz, 9 mJ femtosecond laser pulses, we demonstrate laser-filamentation-induced spectacular snow formation in a cloud chamber. An intense updraft of warm moist air is generated owing to the continuous heating by the high-repetition filamentation. As it encounters the cold air above, water condensation and large-sized particles spread unevenly across the whole cloud chamber via convection and cyclone like action on a macroscopic scale. This indicates that high-repetition filamentation plays a significant role in macroscopic laser-induced water condensation and snow formation.

  8. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers

    International Nuclear Information System (INIS)

    Fowler, W.B.

    1989-01-01

    Proton beams, from the 1GeV Cosmotron accelerator at Brookhaven, were used in the 1950s to produce strange particles. One big leap forward technologically was the development of the diffusion cloud chamber which made detecting particle tracks more accurate and sensitive. A large co-operative team worked on its development. By the mid 1950s enough tracks had been observed to show the associated production of strange particles. It was the same Brookhaven workers who developed the eighty-inch hydrogen bubble chamber which took the first photograph of the long predicted omega minus particle at the end of the decade. (UK)

  9. A review of optical measurements at the aerosol and cloud chamber AIDA

    International Nuclear Information System (INIS)

    Wagner, Robert; Linke, Claudia; Naumann, Karl-Heinz; Schnaiter, Martin; Vragel, Marlen; Gangl, Martin; Horvath, Helmuth

    2009-01-01

    This paper provides a survey of recent studies on the optical properties of aerosol and cloud particles that have been conducted at the AIDA facility of Forschungszentrum Karlsruhe (Aerosol Interactions and Dynamics in the Atmosphere). Reflecting the broad accessible temperature range of the AIDA chamber which extends from ambient temperature down to 183 K, the investigations feature a broad diversity of research topics, such as the wavelength-dependence of the specific absorption cross sections of soot and mineral dust aerosols at room temperature, depolarization and infrared extinction measurements of ice crystal clouds generated at temperatures below 235 K, and the optical properties of polar stratospheric cloud constituents whose formation was studied in chamber experiments at temperatures well below 200 K. After reviewing the AIDA research activity of the past decade and introducing the optical instrumentation of the AIDA facility, this paper presents illustrative examples of ongoing and already published work on optical measurements of soot aerosols, mineral dust particles, and ice crystal clouds.

  10. submitter Phase transition observations and discrimination of small cloud particles by light polarization in expansion chamber experiments

    CERN Document Server

    Nichman, Leonid; Järvinen, Emma; Ignatius, Karoliina; Höppel, Niko Florian; Dias, Antonio; Heinritzi, Martin; Simon, Mario; Tröstl, Jasmin; Wagner, Andrea Christine; Wagner, Robert; Williamson, Christina; Yan, Chao; Connolly, Paul James; Dorsey, James Robert; Duplissy, Jonathan; Ehrhart, Sebastian; Frege, Carla; Gordon, Hamish; Hoyle, Christopher Robert; Kristensen, Thomas Bjerring; Steiner, Gerhard; McPherson Donahue, Neil; Flagan, Richard; Gallagher, Martin William; Kirkby, Jasper; Möhler, Ottmar; Saathoff, Harald; Schnaiter, Martin; Stratmann, Frank; Tomé, António

    2016-01-01

    Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather, and general circulation models. The detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud particle-size range below 50 μm, remains challenging in mixed phase, often unstable environments. The Cloud Aerosol Spectrometer with Polarization (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure the variability in polarization state of their backscattered light. Here we operate the versatile Cosmics Leaving OUtdoor Droplets (CLOUD) chamber facility at the European Organization for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water, and ice particles. In this paper, optical property measurements of mixed-phase clouds and viscous secondary ...

  11. On the possibility of obtaining non-diffused proximity functions from cloud-chamber data: Pt. 2

    International Nuclear Information System (INIS)

    Zaider, M.

    1988-01-01

    Maximum entropy and Bayesian methods are applied to an inversion problem which consists of unfolding diffusion from proximity functions calculated from cloud-chamber data. The solution appears to be relatively insensitive to statistical errors in the data (an important feature) given the limited number of tracks normally available from cloud-chamber measurements. It is the first time, to our knowledge, that such methods are applied to microdosimetry. (author)

  12. Laboratory and Cloud Chamber Studies of Formation Processes and Properties of Atmospheric Ice Particles

    Science.gov (United States)

    Leisner, T.; Abdelmonem, A.; Benz, S.; Brinkmann, M.; Möhler, O.; Rzesanke, D.; Saathoff, H.; Schnaiter, M.; Wagner, R.

    2009-04-01

    The formation of ice in tropospheric clouds controls the evolution of precipitation and thereby influences climate and weather via a complex network of dynamical and microphysical processes. At higher altitudes, ice particles in cirrus clouds or contrails modify the radiative energy budget by direct interaction with the shortwave and longwave radiation. In order to improve the parameterisation of the complex microphysical and dynamical processes leading to and controlling the evolution of tropospheric ice, laboratory experiments are performed at the IMK Karlsruhe both on a single particle level and in the aerosol and cloud chamber AIDA. Single particle experiments in electrodynamic levitation lend themselves to the study of the interaction between cloud droplets and aerosol particles under extremely well characterized and static conditions in order to obtain microphysical parameters as freezing nucleation rates for homogeneous and heterogeneous ice formation. They also allow the observation of the freezing dynamics and of secondary ice formation and multiplication processes under controlled conditions and with very high spatial and temporal resolution. The inherent droplet charge in these experiments can be varied over a wide range in order to assess the influence of the electrical state of the cloud on its microphysics. In the AIDA chamber on the other hand, these processes are observable under the realistic dynamic conditions of an expanding and cooling cloud- parcel with interacting particles and are probed simultaneously by a comprehensive set of analytical instruments. By this means, microphysical processes can be studied in their complex interplay with dynamical processes as for example coagulation or particle evaporation and growth via the Bergeron - Findeisen process. Shortwave scattering and longwave absorption properties of the nucleating and growing ice crystals are probed by in situ polarised laser light scattering measurements and infrared extinction

  13. Survival and ice nucleation activity of bacteria as aerosols in a cloud simulation chamber

    Science.gov (United States)

    Amato, P.; Joly, M.; Schaupp, C.; Attard, E.; Möhler, O.; Morris, C. E.; Brunet, Y.; Delort, A.-M.

    2015-06-01

    The residence time of bacterial cells in the atmosphere is predictable by numerical models. However, estimations of their aerial dispersion as living entities are limited by a lack of information concerning survival rates and behavior in relation to atmospheric water. Here we investigate the viability and ice nucleation (IN) activity of typical atmospheric ice nucleation active bacteria (Pseudomonas syringae and P. fluorescens) when airborne in a cloud simulation chamber (AIDA, Karlsruhe, Germany). Cell suspensions were sprayed into the chamber and aerosol samples were collected by impingement at designated times over a total duration of up to 18 h, and at some occasions after dissipation of a cloud formed by depressurization. Aerosol concentration was monitored simultaneously by online instruments. The cultivability of airborne cells decreased exponentially over time with a half-life time of 250 ± 30 min (about 3.5 to 4.5 h). In contrast, IN activity remained unchanged for several hours after aerosolization, demonstrating that IN activity was maintained after cell death. Interestingly, the relative abundance of IN active cells still airborne in the chamber was strongly decreased after cloud formation and dissipation. This illustrates the preferential precipitation of IN active cells by wet processes. Our results indicate that from 106 cells aerosolized from a surface, one would survive the average duration of its atmospheric journey estimated at 3.4 days. Statistically, this corresponds to the emission of 1 cell that achieves dissemination every ~ 33 min m-2 of cultivated crops fields, a strong source of airborne bacteria. Based on the observed survival rates, depending on wind speed, the trajectory endpoint could be situated several hundreds to thousands of kilometers from the emission source. These results should improve the representation of the aerial dissemination of bacteria in numeric models.

  14. A low-pressure cloud chamber to study the spatial distribution of ionizations

    International Nuclear Information System (INIS)

    Hodges, D.C.; Marshall, M.

    1977-01-01

    To further the understanding of the biological effects of radiation a knowledge of the spatial distribution of ionizations in small volumes is required. A cloud chamber capable of resolving the droplets formed on individual ions in the tracks of low-energy electrons has been constructed. It is made to high-vacuum specifications and contains a mixture of permanent gases and vapours, unsaturated before expansion, at a total pressure of 10 kPa. Condensation efficiencies close to 100% are obtained without significant background from condensation on uncharged particles and molecular aggregates. This paper describes the chamber, associated equipment and method of operation and discusses the performance of the system. Photographs of the droplets produced from the interaction of low-energy X-rays in the chamber gas for various modes of operation are presented. The mean energy loss per ion pair for electrons produced by the interaction of Al X-rays in the chamber gas (8130 Pa H 2 , 700 Pa C 2 H 5 OH, 690 Pa H 2 O, 400 Pa He, 70 Pa air) has been measured as 29.8 +- 0.7 eV per ion pair compared with a calculated value of 29.6 +- 0.4 eV per ion pair. (author)

  15. Development of a turn-key cloud chamber in collaboration with non-academic science enthusiasts

    Science.gov (United States)

    Muenkel, Jessica; Harrington, Meghan; Bellis, Matthew; Waldman, Ariel; Bergey, Nathan; Cooper, Ivan; Bombosch, Juliane

    2014-03-01

    Science Hack Day is an event that brings together scientists and science enthusiasts for 24 hours to ``hack'' a science project. These events serve two purposes. The first and most obvious is to provide a structured environment for science outreach. Academics and researchers have the opportunity for ``boots-on-the-ground'' interactions with the general public. The second purpose, though more challenging, is to enable science enthusiasts to donate their skills so that they are able to push back to educators and researchers in a fashion that that benefits their work. We discuss our experiences at the 2013 San Francisco Science Hack Day at the California Academy of Sciences. We worked with attendees of the conference to create a cloud chamber that worked with Peltier thermocoolers, rather than dry ice. In this fashion, we educated attendees about radiation and particle physics, while also benefitting from the experience and knowledge of the attendees in constructing the device. This ``turn-key'' cloud chamber is now in use at Siena College as an outreach and educational device. The properties of this device and the story of its construction will be presented. Representing CMS.

  16. Decoherence and Determinism in a One-Dimensional Cloud-Chamber Model

    Science.gov (United States)

    Sparenberg, Jean-Marc; Gaspard, David

    2018-03-01

    The hypothesis (Sparenberg et al. in EPJ Web Conf 58:01016, [1]. https://doi.org/10.1051/epjconf/20135801016) that the particular linear tracks appearing in the measurement of a spherically-emitting radioactive source in a cloud chamber are determined by the (random) positions of atoms or molecules inside the chamber is further explored in the framework of a recently established one-dimensional model (Carlone et al. Comm Comput Phys 18:247, [2]. https://doi.org/10.4208/cicp.270814.311214a). In this model, meshes of localized spins 1/2 play the role of the cloud-chamber atoms and the spherical wave is replaced by a linear superposition of two wave packets moving from the origin to the left and to the right, evolving deterministically according to the Schrödinger equation. We first revisit these results using a time-dependent approach, where the wave packets impinge on a symmetric two-sided detector. We discuss the evolution of the wave function in the configuration space and stress the interest of a non-symmetric detector in a quantum-measurement perspective. Next we use a time-independent approach to study the scattering of a plane wave on a single-sided detector. Preliminary results are obtained, analytically for the single-spin case and numerically for up to 8 spins. They show that the spin-excitation probabilities are sometimes very sensitive to the parameters of the model, which corroborates the idea that the measurement result could be determined by the atom positions. The possible origin of decoherence and entropy increase in future models is finally discussed.

  17. Numerical simulations of mixing conditions and aerosol dynamics in the CERN CLOUD chamber

    CERN Document Server

    Voigtländer, J; Rondo, L; Kürten, A; Stratmann, F

    2012-01-01

    To study the effect of galactic cosmic rays on aerosols and clouds, the Cosmics Leaving OUtdoor Droplets (CLOUD) project was established. Experiments are carried out at a 26.1 m3 tank at CERN (Switzerland). In the experiments, the effect of ionizing radiation on H2SO4 particle formation and growth is investigated. To evaluate the experimental configuration, the experiment was simulated using a coupled multidimensional computational fluid dynamics (CFD) – particle model. In the model the coupled fields of gas/vapor species, temperature, flow velocity and particle properties were computed to investigate mixing state and mixing times of the CLOUD tank's contents. Simulation results show that a 1-fan configuration, as used in first experiments, may not be sufficient to ensure a homogeneously mixed chamber. To mix the tank properly, two fans and sufficiently high fan speeds are necessary. The 1/e response times for instantaneous changes of wall temperature and saturation ratio were found to be in the order of fe...

  18. The role of ions in new particle formation in the CLOUD chamber

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2017-12-01

    Full Text Available The formation of secondary particles in the atmosphere accounts for more than half of global cloud condensation nuclei. Experiments at the CERN CLOUD (Cosmics Leaving OUtdoor Droplets chamber have underlined the importance of ions for new particle formation, but quantifying their effect in the atmosphere remains challenging. By using a novel instrument setup consisting of two nanoparticle counters, one of them equipped with an ion filter, we were able to further investigate the ion-related mechanisms of new particle formation. In autumn 2015, we carried out experiments at CLOUD on four systems of different chemical compositions involving monoterpenes, sulfuric acid, nitrogen oxides, and ammonia. We measured the influence of ions on the nucleation rates under precisely controlled and atmospherically relevant conditions. Our results indicate that ions enhance the nucleation process when the charge is necessary to stabilize newly formed clusters, i.e., in conditions in which neutral clusters are unstable. For charged clusters that were formed by ion-induced nucleation, we were able to measure, for the first time, their progressive neutralization due to recombination with oppositely charged ions. A large fraction of the clusters carried a charge at 1.5 nm diameter. However, depending on particle growth rates and ion concentrations, charged clusters were largely neutralized by ion–ion recombination before they grew to 2.5 nm. At this size, more than 90 % of particles were neutral. In other words, particles may originate from ion-induced nucleation, although they are neutral upon detection at diameters larger than 2.5 nm. Observations at Hyytiälä, Finland, showed lower ion concentrations and a lower contribution of ion-induced nucleation than measured at CLOUD under similar conditions. Although this can be partly explained by the observation that ion-induced fractions decrease towards lower ion concentrations, further investigations

  19. Kinematical analysis with the Emulsion Cloud Chamber in the OPERA experiment

    CERN Document Server

    Di Capua, F

    2010-01-01

    The OPERA experiment aims at measuring for the first time neutrino oscil- lation in appearance mode through the detection of ni-tau in an almost pure niμ beam produced at CERN SPS (CNGS), 730 km far from the detector. The ni-tau appearance signal is identified through the measurement of the decay daughter particles of the " lepton produced in CC ni-tau interactions. Since the short-lived " particle has, at the energy of the beam, an average decay length shorter than a 1 mm, a micrometric detection resolution is needed. The OPERA appara- tus is hybrid, using nuclear emulsion as high precision tracker and electronic detectors for the time stamp, event localization in the target and muon recon- struction. The Emulsion Cloud Chamber technique fulfils the requirement of a microscopic resolution together with a large target mass. The kinematical analysis allowed by this technique is described.

  20. Using the thermal diffusion cloud chamber to study the ion-induced nucleation by radon decay

    International Nuclear Information System (INIS)

    Wu, Yefei.

    1991-01-01

    Thermal diffusion cloud chamber is steady-state device and has been extensively used for nucleation research. In order to study the ion-induced nucleation by radon decay, a new chamber was designed with improved both upper and bottom plates, the system of circulating fluid, the gasketting, the temperature measurement and the insulation. An alternative method of using oxygen as carrier gas was examined. Therefore, the heavy carrier gas including nitrogen, oxygen, neon, argon and air can be used to study radon radiolysis-induced nucleation for the water or organic compounds in the TDCC. The effects of the pressure and temperature ranges on the density, supersaturation, temperature and partial pressure profile for the water-oxygen-helium in the TDCC have been examined. Based on the classical theory, the rate profile of ion-induced nucleation by radon decays was calculated and compared with the homogeneous nucleation. From measured indoor concentrations of Volatile Organic Compounds (VOC), thermodynamic theory models were used to assess the possibility that these compounds will form ultrafine particles in indoor air by ion-induced nucleation. The energy, number of molecules and equilibrium radius of clusters have been calculated based on Such and Thomson theories. These two sets of values have been compared. Ion cluster radii corresponding to 1--3 VOC molecules are in range of 3--5 x 10 -8 cm. 43 refs., 18 figs., 5 tabs

  1. Technical Note: A numerical test-bed for detailed ice nucleation studies in the AIDA cloud simulation chamber

    Directory of Open Access Journals (Sweden)

    R. J. Cotton

    2007-01-01

    Full Text Available The AIDA (Aerosol Interactions and Dynamics in the Atmosphere aerosol and cloud chamber of Forschungszentrum Karlsruhe can be used to test the ice forming ability of aerosols. The AIDA chamber is extensively instrumented including pressure, temperature and humidity sensors, and optical particle counters. Expansion cooling using mechanical pumps leads to ice supersaturation conditions and possible ice formation. In order to describe the evolving chamber conditions during an expansion, a parcel model was modified to account for diabatic heat and moisture interactions with the chamber walls. Model results are shown for a series of expansions where the initial chamber temperature ranged from −20°C to −60°C and which used desert dust as ice forming nuclei. During each expansion, the initial formation of ice particles was clearly observed. For the colder expansions there were two clear ice nucleation episodes. In order to test the ability of the model to represent the changing chamber conditions and to give confidence in the observations of chamber temperature and humidity, and ice particle concentration and mean size, ice particles were simply added as a function of time so as to reproduce the observations of ice crystal concentration. The time interval and chamber conditions over which ice nucleation occurs is therefore accurately known, and enables the model to be used as a test bed for different representations of ice formation.

  2. Laser-filamentation-induced water condensation and snow formation in a cloud chamber filled with different ambient gases.

    Science.gov (United States)

    Liu, Yonghong; Sun, Haiyi; Liu, Jiansheng; Liang, Hong; Ju, Jingjing; Wang, Tiejun; Tian, Ye; Wang, Cheng; Liu, Yi; Chin, See Leang; Li, Ruxin

    2016-04-04

    We investigated femtosecond laser-filamentation-induced airflow, water condensation and snow formation in a cloud chamber filled respectively with air, argon and helium. The mass of snow induced by laser filaments was found being the maximum when the chamber was filled with argon, followed by air and being the minimum with helium. We also discussed the mechanisms of water condensation in different gases. The results show that filaments with higher laser absorption efficiency, which result in higher plasma density, are beneficial for triggering intense airflow and thus more water condensation and precipitation.

  3. On-line determination of ammonia at low pptv mixing ratios in the CLOUD chamber

    CERN Document Server

    Bianchi, F; Mathot, S; Baltensperger, U

    2012-01-01

    A new instrument for the on-line determination of ammonia was developed. Since ammonia is a rather sticky compound, sampling losses were minimised with a new sam- pling device where the ammonia was transferred to the liq- uid phase only 5 mm after the inlet tip. The liquid phase was then analyzed by long pathlength absorption spectrophotom- etry using the Berthelot reaction with phenol and hypochlo- rite as reagents. The measurements were made during the CLOUD3 campaign at CERN where the influence of ammo- nia on the nucleation rate was studied. At stable conditions the detection limit reached with this instrument was 35 pptv (air flow rate of 2 l min − 1 , liquid flow rate of 0.3 ml min − 1 ), although occasionally the instrument was affected by back- ground problems. The range of mixing ratios during this campaign was varied from the background contamination ( < 35 pptv) up to around 2 ppbv. The measured ammonia concentration was correlated with the rate of ammonia in- jected into the chamber, but wi...

  4. Investigation concerning the existence of quarks near the nuclei of great air showers with the help of a cloud chamber

    International Nuclear Information System (INIS)

    Wiemken, U.

    1974-01-01

    In order to compare the results of McCusker's (1969) experiment, this paper presents an experiment with improved technical details. For this purpose, a large cloud chamber in connection with the Kiel air shower set-up was available. First, the expected quark induced ionisation has been determined by a calibration measurement on minimum ionising muons. These data are in extremely good agreement with values from the literature. Then, measurements in air showers with a mean primary energy of 10 16 eV have been performed during an effective measuring time of 66 days. The mean distance from the nucleus amounts to about 9 m. In contradiction to the quark abundance of McCusker, which predicts six quarks for the Kiel set-up, no track was found with 'quark suspicion'. Some tracks with low droplet densities could be explained already in a preliminary stage of the evaluation by normal cloud chamber effects. (orig.) [de

  5. A basic radiation-education method using a handy-type cloud chamber and natural radiation sources

    International Nuclear Information System (INIS)

    Kushita, K. N.

    2010-10-01

    Nuclear human resources development becomes increasingly important due to the world trend of expanding nuclear energy utilization in this century. At the Nuclear Human Resource Development Center of the Japan Atomic Energy Agency, many kinds of nuclear and radiation education have been conducted consistently and continuously through its half-century history though having several organizational changes. High level education is required for the specialists of nuclear technology including nuclear power plants operators and engineers, while basic knowledge on nuclear energy and, specially, on radiations and radioisotopes should be given to school students and public. Besides lectures on radiation and radioisotopes, some basic experiments are useful to understand what are radiations and radioisotopes. One of such basic experiments is the cloud chamber experiment. It is a great fun and excitement even for small children as one can actually see the radiation tracks by his/her naked eyes at hand. While there are many types of cloud chambers, we have developed a new-type cloud chamber to use for the radiation education and training s. Using the new-type cloud chamber, we have further developed a new method of this experiment so that the participants can more deeply understand the phenomena and the nature of radiation and radioisotopes. In this method, using a radiation source of natural uranium ore and gaseous radiation source containing Rn-220 obtained from thorium-containing material, they not only observe the radiation tracks but also measure the length and count the number of the tracks. Then they can calculate the energy of the radiation (alpha ray) and can estimate the half-life of the radioisotope (Rn-220). This method can be applied for high-school and general university students as well as for the public as a useful and effective method in the radiation education. (Author)

  6. A basic radiation-education method using a handy-type cloud chamber and natural radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Kushita, K. N., E-mail: Kushita.kouhei@iaea.go.j [Japan Atomic Energy Agency, Nuclear Human Resource Development Center, 2-4 Shirakata-Shirane, Tokai, Naka, Ibaraki 309-1195 (Japan)

    2010-10-15

    Nuclear human resources development becomes increasingly important due to the world trend of expanding nuclear energy utilization in this century. At the Nuclear Human Resource Development Center of the Japan Atomic Energy Agency, many kinds of nuclear and radiation education have been conducted consistently and continuously through its half-century history though having several organizational changes. High level education is required for the specialists of nuclear technology including nuclear power plants operators and engineers, while basic knowledge on nuclear energy and, specially, on radiations and radioisotopes should be given to school students and public. Besides lectures on radiation and radioisotopes, some basic experiments are useful to understand what are radiations and radioisotopes. One of such basic experiments is the cloud chamber experiment. It is a great fun and excitement even for small children as one can actually see the radiation tracks by his/her naked eyes at hand. While there are many types of cloud chambers, we have developed a new-type cloud chamber to use for the radiation education and training s. Using the new-type cloud chamber, we have further developed a new method of this experiment so that the participants can more deeply understand the phenomena and the nature of radiation and radioisotopes. In this method, using a radiation source of natural uranium ore and gaseous radiation source containing Rn-220 obtained from thorium-containing material, they not only observe the radiation tracks but also measure the length and count the number of the tracks. Then they can calculate the energy of the radiation (alpha ray) and can estimate the half-life of the radioisotope (Rn-220). This method can be applied for high-school and general university students as well as for the public as a useful and effective method in the radiation education. (Author)

  7. Cosmic-ray cloud-chamber contributions to the discovery of the strange particles in the decade 1947-1957

    International Nuclear Information System (INIS)

    Rochester, G.D.

    1989-01-01

    This paper looks at the discovery and investigation of strange particles in the 1950s and points to the importance of two factors in achieving this, namely, penetrating-shower selection and counter control in cloud chambers. Experiments at Pic-du-Mide are detailed as is the Bagneres de Bigorre conference and concludes with some of the work done on charged strange particles. (UK)

  8. A Study of the Link between Cosmic Rays and Clouds with a Cloud Chamber at the CERN PS

    CERN Multimedia

    Laakso, L K; Lehtipalo, K; Miettinen, P K; Duarte branco da silva santos, F; Stojkov, Y; Jud, W; Wurm, F; Pinterich, T; Dommen, J; Curtius, J; Kreissl, F C; Minginette, P; Azeredo lima, J M; Kulmala, M T; Petaja, T T; Volkamer, R M; Schafer, M; Rodrigues tome, A; Viisanen, Y A; Onnela, A T O; Kristic, R; Ehrhart, S K; Amorim, A J; Maksumov, O; Kupc, A; Sitals, R P; Dunne, E M; Riipinen, I A; Downard, A J; Virtanen, A; Tsagkogeorgas, G; Schuchmann, S; Kvashnin, A; Hansel, A; Gonzalez carracedo, L R; Vrtala, A; Schallhart, S; Yan, C; Stratmann, F; Pinto mogo, S I; Makhmutov, V; Riccobono, F; Weingartner, E P; Kurten, C A; Rondo, L; Ruuskanen, T M; Finkenzeller, H F; Laaksonen, A J; De menezes, L; Hauser, D; Kajos, M K; Schmitt, T M; Mathot, S; Wasem, A; Guida, R; Metzger, A E; Baltensperger, U; Kirkby, J; Duplissy, J; Franchin, A; Rorup, B; Flagan, R C; Wex, H D

    2002-01-01

    Three recent independent observations suggest that galactic cosmic rays may exert a significant influence on the climate. Firstly, satellite data suggest a positive correlation between variations of cosmic ray intensity and the fraction of Earth covered by low clouds. Secondly, palaeoclimatic data provide extensive evidence for an association between cosmic ray intensity and climate over the last 10 kyr and at earlier times. Finally, the presence of ion-induced nucleation of new aerosol in the atmosphere is supported by recent observations. If cosmic rays do indeed enhance aerosol production and low cloud formation, this could exert a strong cooling influence on the radiative energy balance of Earth. Physical mechanisms by which cosmic rays may affect aerosol and clouds have been proposed and modelled, but definitive experiments are lacking. The aim of CLOUD is to investigate the nature and significance of cosmic ray-aerosol-cloud mechanisms under controlled laboratory conditions using the T11 beam at the CER...

  9. Laser-filament-induced snow formation in a subsaturated zone in a cloud chamber: experimental and theoretical study.

    Science.gov (United States)

    Ju, Jingjing; Sun, Haiyi; Sridharan, Aravindan; Wang, Tie-Jun; Wang, Cheng; Liu, Jiansheng; Li, Ruxin; Xu, Zhizhan; Chin, See Leang

    2013-12-01

    1 kHz, 2 mJ, 45 fs, 800 nm laser pulses were fired into a laboratory diffusion cloud chamber through a subsaturated zone (relative humidity ∼73%, T ∼ 4.3 °C). After 60 min of laser irradiation, an oval-shaped snow pile was observed right below the filament center and weighed ∼12.0 mg. The air current velocity at the edge of the vortices was estimated to be ∼16.5 cm/s. Scattering scenes recorded from the side show that filament-induced turbulence were formed inside the cloud chamber with two vortices below the filament. Two-dimensional simulations of the air flow motion in two cross sections of the cloud chamber confirm that the turbulent vortices exist below the filament. Based upon this simulation, we deduce that the vortices indeed have a three-dimensional elliptical shape. Hence, we propose that inside vortices where the humidity was supersaturated or saturated the condensation nuclei, namely, HNO(3), N(2)(+), O(2)(+) and other aerosols and impurities, were activated and grew in size. Large-sized particles would eventually be spun out along the fast moving direction towards the cold plate and formed an oval-shaped snow pile at the end.

  10. A study of the link between cosmic rays and clouds with a cloud chamber at the CERN PS

    CERN Document Server

    Fastrup, B; Lillestøl, Egil; Thorn, E; Bosteels, Michel; Gonidec, A; Harigel, G G; Kirkby, Jasper; Mele, S; Minginette, P; Nicquevert, Bertrand; Schinzel, D; Seidl, W; Grundsøe, P; Marsh, N D; Polny, J; Svensmark, H; Viisanen, Y; Kurvinen, K L; Orava, Risto; Hämeri, K; Kulmala, M; Laakso, I; Mäkelä, J M; O'Dowd, C D; Afrosimov, V; Basalaev, A; Panov, M; Laaksonen, B D; Joutsensaari, J; Ermakov, V; Makhmutov, V S; Maksumov, O; Pokrevsky, P; Stozhkov, Yu I; Svirzhevsky, N S; Carslaw, K; Yin, Y; Trautmann, T; Arnold, F; Wohlfrom, K H; Hagen, D; Schmitt, J; Whitefield, P; Aplin, K; Harrison, R G; Bingham, R; Close, Francis Edwin; Gibbins, C; Irving, A; Kellett, B; Lockwood, M; Petersen, D; Szymanski, W W; Wagner, P E; Vrtala, A; CERN. Geneva. SPS-PS Experiments Committee

    2000-01-01

    Recent satellite data have revealed a surprising correlation between galactic cosmic ray (GCR) intensity and the fraction of the Earth covered by clouds. If this correlation were to be established by a causal mechanism, it could provide a crucial step in understanding the long-sought mechanism connecting solar and climate variability. The Earth's climate seems to be remarkably sensitive to solar activity, but variations of the Sun's electromagnetic radiation appear to be too small to account for the observed climate variability. However, since the GCR intensity is strongly modulated by the solar wind, a GCR-cloud link may provide a sufficient amplifying mechanism. Moreover if this connection were to be confirmed, it could have profound consequences for our understanding of the solar contributions to the current global warming. The CLOUD (Cosmics Leaving OUtdoor Droplets) project proposes to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical me...

  11. Design of a new multi-phase experimental simulation chamber for atmospheric photosmog, aerosol and cloud chemistry research

    Directory of Open Access Journals (Sweden)

    J. Wang

    2011-11-01

    Full Text Available A new simulation chamber has been built at the Interuniversitary Laboratory of Atmospheric Systems (LISA. The CESAM chamber (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber is designed to allow research in multiphase atmospheric (photo- chemistry which involves both gas phase and condensed phase processes including aerosol and cloud chemistry. CESAM has the potential to carry out variable temperature and pressure experiments under a very realistic artificial solar irradiation. It consists of a 4.2 m3 stainless steel vessel equipped with three high pressure xenon arc lamps which provides a controlled and steady environment. Initial characterization results, all carried out at 290–297 K under dry conditions, concerning lighting homogeneity, mixing efficiency, ozone lifetime, radical sources, NOy wall reactivity, particle loss rates, background PM, aerosol formation and cloud generation are given. Photolysis frequencies of NO2 and O3 related to chamber radiation system were found equal to (4.2 × 10−3 s−1 for JNO2 and (1.4 × 10−5 s−1 for JO1D which is comparable to the solar radiation in the boundary layer. An auxiliary mechanism describing NOy wall reactions has been developed. Its inclusion in the Master Chemical Mechanism allowed us to adequately model the results of experiments on the photo-oxidation of propene-NOx-Air mixtures. Aerosol yields for the α-pinene + O3 system chosen as a reference were determined and found in good agreement with previous studies. Particle lifetime in the chamber ranges from 10 h to 4 days depending on particle size distribution which indicates that the chamber can provide high quality data on aerosol aging processes and their effects. Being evacuable, it is possible to generate in this new chamber

  12. New Particle Formation in an Urban Atmosphere: The Role of Various Ingredients Investigated in the CLOUD Chamber

    Science.gov (United States)

    Baltensperger, U.; Xiao, M.; Hoyle, C.; Dada, L.; Garmash, O.; Stolzenburg, D.; Molteni, U.; Lehtipalo, K.; El-Haddad, I.; Dommen, J.

    2017-12-01

    Atmospheric aerosols play an important role on climate via aerosol-radiation interaction and aerosol-cloud interaction. The latter is strongly influenced by new particle formation (NPF). The physical and chemical mechanisms behind the NPF process are still under investigation. Great advancements were made in resolving chemical and physical mechanisms of NPF with a series of experiments conducted at the CLOUD (Cosmics Leaving Outdoor Droplets) chamber facility at CERN (Geneva, Switzerland), including binary nucleation of sulfuric acid - water, ternary nucleation of sulfuric acid - water with ammonia or dimethylamine as well as oxidation products (highly oxygenated molecules, HOMs) from biogenic precursors with and without the presence of sulfuric acid. Here, we investigate possible NPF mechanisms in urban atmospheres, where large populations are exposed to high aerosol concentrations; these mechanisms are still missing and are urgently needed. Urban atmospheres are highly polluted with high concentrations of SO2, ammonia, NOx and volatile organic vapors from anthropogenic activity as well as with high particle concentrations, which provide a high condensation sink for condensable gases. Aromatic hydrocarbons from industrial activities, traffic and residential combustion are present at high concentrations and contribute significantly to photochemical smog in the urban environment.The experiments were conducted at the CLOUD chamber facility during the CLOUD11 campaign in fall 2016. Three aromatic hydrocarbons were selected: toluene, 1,2,4-trimethylbenzene (1,2,4-TMB) and naphthalene (NPT). Experiments were also conducted with mixtures of the three aromatic hydrocarbons to better represent the urban atmosphere. All the experiments were conducted in the presence of sulfuric acid concentrations with or without the addition of ammonia and NOx. New particle formation rates and early growth rates derived for each precursor and their mixture, together with sulfuric acid and

  13. Cloud Experiment. View inside the chamber with Jasper Kirkby, Head leader of the project.

    CERN Multimedia

    Maximilien Brice

    2009-01-01

    CLOUD, the cutting-edge physics experiment that will shed light on climate-related matters, has finished its assembly phase and is starting taking data using a beam of protons from the Proton Synchrotron.

  14. submitter Modeling the thermodynamics and kinetics of sulfuric acid-dimethylamine-water nanoparticle growth in the CLOUD chamber

    CERN Document Server

    Ahlm, L; Schobesberger, S; Praplan, A P; Kim, J; Tikkanen, O -P; Lawler, M J; Smith, J N; Tröstl, J; Acosta Navarro, J C; Baltensperger, U; Bianchi, F; Donahue, N M; Duplissy, J; Franchin, A; Jokinen, T; Keskinen, H; Kirkby, J; Kürten, A; Laaksonen, A; Lehtipalo, K; Petäjä, T; Riccobono, F; Rissanen, M P; Rondo, L; Schallhart, S; Simon, M; Winkler, P M; Worsnop, D R; Virtanen, A; Riipinen, I

    2016-01-01

    Dimethylamine (DMA) has a stabilizing effect on sulfuric acid (SA) clusters, and the SA and DMA molecules and clusters likely play important roles in both aerosol particle formation and growth in the atmosphere. We use the monodisperse particle growth model for acid-base chemistry in nanoparticle growth (MABNAG) together with direct and indirect observations from the CLOUD4 and CLOUD7 experiments in the cosmics leaving outdoor droplets (CLOUD) chamber at CERN to investigate the size and composition evolution of freshly formed particles consisting of SA, DMA, and water as they grow to 20 nm in dry diameter. Hygroscopic growth factors are measured using a nano-hygroscopicity tandem differential mobility analyzer (nano-HTDMA), which combined with simulations of particle water uptake using the thermodynamic extended-aerosol inorganics model (E-AIM) constrain the chemical composition. MABNAG predicts a particle-phase ratio between DMA and SA molecules of 1.1–1.3 for a 2 nm particle and DMA gas-phase mixing ratio...

  15. The origin of the cloud chamber;Les mysteres de la chambre a brouillard

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, K. [Palais de la Decouverte, Dept. de Physique, 75 - Paris (France)

    2009-09-15

    This article draws the story of the Wilson chamber. In the second half of the 19. century, a general trend among scientists in Great-Britain was still the observation and the imitation of nature, this romantic approach was launched by Goethe 50 years before. In 1895, Wilson as a young physicist tried to reproduce fog in laboratory. His challenge was to reduce the role of dust particles in the Aitken method: the expansion of wet-saturated air loaded with dust particles creates fog. In 1896, at the Cavendish laboratory, he discovered that ions could be very efficient 'dust particles' to condensate vapor and in 1898 he wrote that the expansion method is probably one of the most sensitive method to detect radiation emitted by radioactive materials. The Wilson chamber got a full success only from the twenties and was intensively used for 30 years in particles and nuclear physics laboratories. This detector allowed the experimental discovery of the positron, the muon and strange particles. (A.C.)

  16. Application of the monazite radiation source to the petri dish-type cloud chamber and the influence of several factors on occurrence of tracks

    International Nuclear Information System (INIS)

    Hayakawa, Issei; Sago, Yutaka; Mori, Chizuo

    2012-01-01

    Monazite radiation source (2.5 mmΦ) proved to be useful as a radiation source of cloud chamber without the dispersion of powder or its adhesion because of a sintered body. After the track appeared within one minute after having put the petri dish on the dry ice, the number increased rapidly followed by the tendency to decrease gradually after that. The tracks can be observed for about 20 minutes after cooled with dry ice. The size of dry ice should be chosen to enter the inside of the bottom edge of the petri dish. The same number of tracks as using conventional mantle radiation source was obtained by utilizing 3 pieces of monazite sintered body separated mutually by about 7.5 mm. Hence the petri dish-type cloud chamber with the monazite sintered body as radiation source revealed to make the observation of track easy and prompt. (author)

  17. Continuum Regime Motion of a Growing Droplet in Opposing Thermo-Diffusiophoretic and Gravitational Fields of a Thermal Diffusion Cloud Chamber

    Czech Academy of Sciences Publication Activity Database

    Bakanov, S. P.; Smolík, Jiří; Zaripov, S. K.; Ždímal, Vladimír

    2001-01-01

    Roč. 32, č. 3 (2001), s. 341-350 ISSN 0021-8502 R&D Projects: GA ČR GA104/97/1198 Grant - others:RFBR(RU) 99-01-00-169 Institutional research plan: CEZ:AV0Z4072921 Keywords : thermal diffusion cloud chamber * droplet growth * continuum regime Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.605, year: 2001

  18. A new laboratory facility to study the interactions of aerosols, cloud droplets/ice crystals, and trace gases in a turbulent environment: The Π Chamber

    Science.gov (United States)

    Cantrell, W. H., II; Chang, K.; Ciochetto, D.; Niedermeier, D.; Bench, J.; Shaw, R. A.

    2014-12-01

    A detailed understanding of gas-aerosol-cloud interaction within the turbulent atmosphere is of prime importance for an accurate understanding of Earth's climate system. As one example: While every cloud droplet began as an aerosol particle, not every aerosol particle becomes a cloud droplet. The particle to droplet transformation requires that the particle be exposed to some critical concentration of water vapor, which differs for different combinations of particle size and chemical composition. Similarly, the formation of ice particles in mixed phase clouds is also catalyzed by aerosol particles. Even in the simplest scenarios it is challenging to gain a full understanding of the aerosol activation and ice nucleation processes. At least two other factors contribute significantly to the complexity observed in the atmosphere. First, aerosols and cloud particles are not static entities, but are continuously interacting with their chemical environment, and therefore changing in their properties. Second, clouds are ubiquitously turbulent, so thermodynamic and compositional variables, such as water vapor or other trace gas concentrations, fluctuate in space and time. Indeed, the coupling between turbulence and microphysical processes is one of the major research challenges in cloud physics. We have developed a multiphase, turbulent reaction chamber, (dubbed the Π Chamber, after the internal volume of 3.14 cubic meters) designed to address the problems outlined above. It is capable of pressures ranging from sea level to ~ 100 mbar, and can sustain temperatures of +40 to -55 ºC. We can independently control the temperatures on the surfaces of three heat transfer zones. This allows us to establish a temperature gradient between the floor and ceiling inducing Rayleigh-Benard convection and inducing a turbulent environment. Interior surfaces are electropolished stainless steel to facilitate cleaning before and after chemistry experiments. At present, supporting

  19. Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

    CERN Document Server

    2016-01-01

    Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

  20. Exact and near backscattering measurements of the linear depolarisation ratio of various ice crystal habits generated in a laboratory cloud chamber

    Science.gov (United States)

    Smith, Helen R.; Connolly, Paul J.; Webb, Ann R.; Baran, Anthony J.

    2016-07-01

    Ice clouds were generated in the Manchester Ice Cloud Chamber (MICC), and the backscattering linear depolarisation ratio, δ, was measured for a variety of habits. To create an assortment of particle morphologies, the humidity in the chamber was varied throughout each experiment, resulting in a range of habits from the pristine to the complex. This technique was repeated at three temperatures: -7 °C, -15 °C and -30 °C, in order to produce both solid and hollow columns, plates, sectored plates and dendrites. A linearly polarised 532 nm continuous wave diode laser was directed through a section of the cloud using a non-polarising 50:50 beam splitter. Measurements of the scattered light were taken at 178°, 179° and 180°, using a Glan-Taylor prism to separate the co- and cross-polarised components. The intensities of these components were measured using two amplified photodetectors and the ratio of the cross- to co-polarised intensities was measured to find the linear depolarisation ratio. In general, it was found that Ray Tracing over-predicts the linear depolarisation ratio. However, by creating more accurate particle models which better represent the internal structure of ice particles, discrepancies between measured and modelled results (based on Ray Tracing) were reduced.

  1. Role of visualization of nuclear radiation in public education on atomic energy. Visualization of natural nuclear radiation using a cloud chamber

    International Nuclear Information System (INIS)

    Kaneko, Junichi H.; Fujita, Fumiyuki; Narabayashi, Tadashi

    2008-01-01

    Nuclear radiation is indispensable tool, i.e., medical diagnostic systems and industrial nondestructive measurement systems, for our life. On the other hand, ordinary people sometimes have bad image for nuclear radiation. To improve this undesirable situation, many individuals and groups keep holding public educational meeting on nuclear radiation. For this purpose, visualization of natural nuclear radiation by a cloud chamber is very effective way; participants feel existence of nuclear radiation directly. In this talk, public educational activity of Hokkaido University and Japan Atomic Energy Society Hokkaido branch will be reported. (author)

  2. Exact and near backscattering measurements of the linear depolarisation ratio of various ice crystal habits generated in a laboratory cloud chamber

    International Nuclear Information System (INIS)

    Smith, Helen R.; Connolly, Paul J.; Webb, Ann R.; Baran, Anthony J.

    2016-01-01

    Ice clouds were generated in the Manchester Ice Cloud Chamber (MICC), and the backscattering linear depolarisation ratio, δ, was measured for a variety of habits. To create an assortment of particle morphologies, the humidity in the chamber was varied throughout each experiment, resulting in a range of habits from the pristine to the complex. This technique was repeated at three temperatures: −7 °C, −15 °C and −30 °C, in order to produce both solid and hollow columns, plates, sectored plates and dendrites. A linearly polarised 532 nm continuous wave diode laser was directed through a section of the cloud using a non-polarising 50:50 beam splitter. Measurements of the scattered light were taken at 178°, 179° and 180°, using a Glan–Taylor prism to separate the co- and cross-polarised components. The intensities of these components were measured using two amplified photodetectors and the ratio of the cross- to co-polarised intensities was measured to find the linear depolarisation ratio. In general, it was found that Ray Tracing over-predicts the linear depolarisation ratio. However, by creating more accurate particle models which better represent the internal structure of ice particles, discrepancies between measured and modelled results (based on Ray Tracing) were reduced. - Highlights: • Linear depolarisation ratio was measured for various crystal habits. • Measurements were taken at 178°, 179° and 180°. • Various crystal properties were modelled and tested in ray tracing. • Measured and modelled results are discussed. • Modelled results are generally found to overpredict LDR.

  3. The Horizontal Ice Nucleation Chamber (HINC): INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch

    Science.gov (United States)

    Lacher, Larissa; Lohmann, Ulrike; Boose, Yvonne; Zipori, Assaf; Herrmann, Erik; Bukowiecki, Nicolas; Steinbacher, Martin; Kanji, Zamin A.

    2017-12-01

    In this work we describe the Horizontal Ice Nucleation Chamber (HINC) as a new instrument to measure ambient ice-nucleating particle (INP) concentrations for conditions relevant to mixed-phase clouds. Laboratory verification and validation experiments confirm the accuracy of the thermodynamic conditions of temperature (T) and relative humidity (RH) in HINC with uncertainties in T of ±0.4 K and in RH with respect to water (RHw) of ±1.5 %, which translates into an uncertainty in RH with respect to ice (RHi) of ±3.0 % at T > 235 K. For further validation of HINC as a field instrument, two measurement campaigns were conducted in winters 2015 and 2016 at the High Altitude Research Station Jungfraujoch (JFJ; Switzerland, 3580 m a. s. l. ) to sample ambient INPs. During winters 2015 and 2016 the site encountered free-tropospheric conditions 92 and 79 % of the time, respectively. We measured INP concentrations at 242 K at water-subsaturated conditions (RHw = 94 %), relevant for the formation of ice clouds, and in the water-supersaturated regime (RHw = 104 %) to represent ice formation occurring under mixed-phase cloud conditions. In winters 2015 and 2016 the median INP concentrations at RHw = 94 % was below the minimum detectable concentration. At RHw = 104 %, INP concentrations were an order of magnitude higher, with median concentrations in winter 2015 of 2.8 per standard liter (std L-1; normalized to standard T of 273 K and pressure, p, of 1013 hPa) and 4.7 std L-1 in winter 2016. The measurements are in agreement with previous winter measurements obtained with the Portable Ice Nucleation Chamber (PINC) of 2.2 std L-1 at the same location. During winter 2015, two events caused the INP concentrations at RHw = 104 % to significantly increase above the campaign average. First, an increase to 72.1 std L-1 was measured during an event influenced by marine air, arriving at the JFJ from the North Sea and the Norwegian Sea. The contribution from anthropogenic or other

  4. New particle formation in the sulfuric acid–dimethylamine–water system: reevaluation of CLOUD chamber measurements and comparison to an aerosol nucleation and growth model

    Directory of Open Access Journals (Sweden)

    A. Kürten

    2018-01-01

    Full Text Available A recent CLOUD (Cosmics Leaving OUtdoor Droplets chamber study showed that sulfuric acid and dimethylamine produce new aerosols very efficiently and yield particle formation rates that are compatible with boundary layer observations. These previously published new particle formation (NPF rates are reanalyzed in the present study with an advanced method. The results show that the NPF rates at 1.7 nm are more than a factor of 10 faster than previously published due to earlier approximations in correcting particle measurements made at a larger detection threshold. The revised NPF rates agree almost perfectly with calculated rates from a kinetic aerosol model at different sizes (1.7 and 4.3 nm mobility diameter. In addition, modeled and measured size distributions show good agreement over a wide range of sizes (up to ca. 30 nm. Furthermore, the aerosol model is modified such that evaporation rates for some clusters can be taken into account; these evaporation rates were previously published from a flow tube study. Using this model, the findings from the present study and the flow tube experiment can be brought into good agreement for the high base-to-acid ratios (∼ 100 relevant for this study. This confirms that nucleation proceeds at rates that are compatible with collision-controlled (a.k.a. kinetically controlled NPF for the conditions during the CLOUD7 experiment (278 K, 38 % relative humidity, sulfuric acid concentration between 1  ×  106 and 3  ×  107 cm−3, and dimethylamine mixing ratio of ∼  40 pptv, i.e., 1  ×  109 cm−3.

  5. New particle formation in the sulfuric acid-dimethylamine-water system: reevaluation of CLOUD chamber measurements and comparison to an aerosol nucleation and growth model

    Science.gov (United States)

    Kürten, Andreas; Li, Chenxi; Bianchi, Federico; Curtius, Joachim; Dias, António; Donahue, Neil M.; Duplissy, Jonathan; Flagan, Richard C.; Hakala, Jani; Jokinen, Tuija; Kirkby, Jasper; Kulmala, Markku; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Onnela, Antti; Rissanen, Matti P.; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Tröstl, Jasmin; Ye, Penglin; McMurry, Peter H.

    2018-01-01

    A recent CLOUD (Cosmics Leaving OUtdoor Droplets) chamber study showed that sulfuric acid and dimethylamine produce new aerosols very efficiently and yield particle formation rates that are compatible with boundary layer observations. These previously published new particle formation (NPF) rates are reanalyzed in the present study with an advanced method. The results show that the NPF rates at 1.7 nm are more than a factor of 10 faster than previously published due to earlier approximations in correcting particle measurements made at a larger detection threshold. The revised NPF rates agree almost perfectly with calculated rates from a kinetic aerosol model at different sizes (1.7 and 4.3 nm mobility diameter). In addition, modeled and measured size distributions show good agreement over a wide range of sizes (up to ca. 30 nm). Furthermore, the aerosol model is modified such that evaporation rates for some clusters can be taken into account; these evaporation rates were previously published from a flow tube study. Using this model, the findings from the present study and the flow tube experiment can be brought into good agreement for the high base-to-acid ratios (˜ 100) relevant for this study. This confirms that nucleation proceeds at rates that are compatible with collision-controlled (a.k.a. kinetically controlled) NPF for the conditions during the CLOUD7 experiment (278 K, 38 % relative humidity, sulfuric acid concentration between 1 × 106 and 3 × 107 cm-3, and dimethylamine mixing ratio of ˜ 40 pptv, i.e., 1 × 109 cm-3).

  6. The Horizontal Ice Nucleation Chamber (HINC: INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch

    Directory of Open Access Journals (Sweden)

    L. Lacher

    2017-12-01

    Full Text Available In this work we describe the Horizontal Ice Nucleation Chamber (HINC as a new instrument to measure ambient ice-nucleating particle (INP concentrations for conditions relevant to mixed-phase clouds. Laboratory verification and validation experiments confirm the accuracy of the thermodynamic conditions of temperature (T and relative humidity (RH in HINC with uncertainties in T of ±0.4 K and in RH with respect to water (RHw of ±1.5 %, which translates into an uncertainty in RH with respect to ice (RHi of ±3.0 % at T > 235 K. For further validation of HINC as a field instrument, two measurement campaigns were conducted in winters 2015 and 2016 at the High Altitude Research Station Jungfraujoch (JFJ; Switzerland, 3580 m a. s. l.  to sample ambient INPs. During winters 2015 and 2016 the site encountered free-tropospheric conditions 92 and 79 % of the time, respectively. We measured INP concentrations at 242 K at water-subsaturated conditions (RHw = 94 %, relevant for the formation of ice clouds, and in the water-supersaturated regime (RHw = 104 % to represent ice formation occurring under mixed-phase cloud conditions. In winters 2015 and 2016 the median INP concentrations at RHw = 94 % was below the minimum detectable concentration. At RHw = 104 %, INP concentrations were an order of magnitude higher, with median concentrations in winter 2015 of 2.8 per standard liter (std L−1; normalized to standard T of 273 K and pressure, p, of 1013 hPa and 4.7 std L−1 in winter 2016. The measurements are in agreement with previous winter measurements obtained with the Portable Ice Nucleation Chamber (PINC of 2.2 std L−1 at the same location. During winter 2015, two events caused the INP concentrations at RHw = 104 % to significantly increase above the campaign average. First, an increase to 72.1 std L−1 was measured during an event influenced by marine air, arriving at the JFJ

  7. Simulated Field Trials Using an Indoor Aerosol Test Chamber

    National Research Council Canada - National Science Library

    Semler, D. D; Roth, A. P; Semler, K. A; Nolan, P. M

    2004-01-01

    .... In this method, the aerosol chamber control software manipulates circulation fan speeds, chamber vacuum and agent spray times to produce a simulated dynamic cloud within the aerosol test chamber...

  8. Simulated Field Trials Using An Indoor Aerosol Test Chamber

    National Research Council Canada - National Science Library

    Semler, D. D; Roth, A. P; Semler, K. A; Nolan, P. M

    2004-01-01

    .... In this method, the aerosol chamber control software manipulates circulation fan speeds, chamber vacuum and agent spray times to produce a simulated dynamic cloud within the aerosol test chamber...

  9. On CLOUD nine

    CERN Multimedia

    2009-01-01

    The team from the CLOUD experiment - the world’s first experiment using a high-energy particle accelerator to study the climate - were on cloud nine after the arrival of their new three-metre diameter cloud chamber. This marks the end of three years’ R&D and design, and the start of preparations for data taking later this year.

  10. Ionization chamber

    International Nuclear Information System (INIS)

    Jilbert, P.H.

    1975-01-01

    The invention concerns ionization chambers with particular reference to air-equivalent ionization chambers. In order to ensure that similar chambers have similar sensitivities and responses the surface of the chamber bounding the active volume carries a conducting material, which may be a colloidal graphite, arranged in the form of lines so that the area of the conducting material occupies only a small proportion of the area of said surface. (U.S.)

  11. Test chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2009-01-01

    A test chamber for measuring electromagnetic radiation emitted by an apparatus to be tested or for exposing an apparatus to be tested to an electromagnetic radiation field. The test chamber includes a reverberation chamber made of a conductive tent fabric. To create a statistically uniform field in

  12. Ussing Chamber

    NARCIS (Netherlands)

    Westerhout, J.; Wortelboer, H.; Verhoeckx, K.

    2015-01-01

    The Ussing chamber system is named after the Danish zoologist Hans Ussing, who invented the device in the 1950s to measure the short-circuit current as an indicator of net ion transport taking place across frog skin (Ussing and Zerahn, Acta Physiol Scand 23:110-127, 1951). Ussing chambers are

  13. wire chamber

    CERN Multimedia

    Proportional multi-wire chamber. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle. Proportional wire chambers allow a much quicker reading than the optical or magnetoscriptive readout wire chambers.

  14. Drift chamber

    International Nuclear Information System (INIS)

    Inagaki, Yosuke

    1977-01-01

    Drift chamber is becoming an important detector in high energy physics as a precision and fast position detector because of its high spatial resolution and count-rate. The basic principle is that it utilizes the drift at constant speed of electrons ionized along the tracks of charged particles towards the anode wire in the nearly uniform electric field. The method of measuring drift time includes the analog and digital ones. This report describes about the construction of and the application of electric field to the drift chamber, mathematical analysis on the electric field and equipotential curve, derivation of spatial resolution and the factor for its determination, and selection of gas to be used. The performance test of the chamber was carried out using a small test chamber, the collimated β source of Sr-90, and 500 MeV/C electron beam from the 1.3 GeV electron synchrotron in the Institute of Nuclear Study, University of Tokyo. Most chambers to date adopted one dimensional read-out, but it is very advantageous if the two dimensional read-out is feasible with one chamber when the resolution in that direction is low. The typical methods of delay line and charge division for two dimensional read-out are described. The development of digital read-out system is underway, which can process the signal of a large scale drift chamber at high speed. (Wakatsuki, Y.)

  15. Wire Chamber

    CERN Multimedia

    Magnetoscriptive readout wire chamber. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  16. Wire chamber

    CERN Multimedia

    1967-01-01

    Magnetoscriptive readout wire chamber.Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  17. Ionization chamber

    International Nuclear Information System (INIS)

    1977-01-01

    An improved ionization chamber type X-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is placed next to the anode and is maintained at a voltage intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting towards the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  18. Ionization chambers

    International Nuclear Information System (INIS)

    Boag, J.W.

    1987-01-01

    Although a variety of solid-state and chemical methods for measuring radiation dose have been developed in recent decades and calorimetry can now provide an absolute standard of reference, ionization dosimetry retains its position as the most widely used, most convenient, and, in most situations, most accurate method of measuring either exposure or absorbed dose. The ionization chamber itself is the central element in this system of dosimetry. In this chapter the principles governing the construction and operation of ionization chambers of various types are examined. Since the ionization chambers now in general use are nearly all of commercial manufacture, the emphasis is on operating characteristics and interpretation of measurements rather than on details of construction, although some knowledge of the latter is often required when applying necessary corrections to the measured quantities. Examples are given of the construction of typical chambers designed for particular purposes, and the methods of calibrating them are discussed

  19. wire chamber

    CERN Multimedia

    1985-01-01

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  20. Wire chamber

    CERN Multimedia

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  1. wire chamber

    CERN Multimedia

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  2. wire chamber

    CERN Multimedia

    Was used in ISR (Intersecting Storage Ring) split field magnet experiment. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  3. Chamber transport

    International Nuclear Information System (INIS)

    Olson, Craig L.

    2001-01-01

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system

  4. Doriot Climatic Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — The Doriot Climatic Chambers are two, 60-feet long, 11-feet high, 15-feet wide chambers that are owned and operated by NSRDEC. The Doriot Climatic Chambers are among...

  5. Directed Energy Anechoic Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The Directed Energy Anechoic Chamber comprises a power anechoic chamber and one transverse electromagnetic cell for characterizing radiofrequency (RF) responses of...

  6. Multiple chamber ionization detector

    International Nuclear Information System (INIS)

    Solomon, E.E.

    1980-01-01

    A multi-chambered ionisation detector enables the amount of radiation entering each chamber from a single radioactive, eg β, source to be varied by altering the proportion of the source protruding into each chamber. Electrodes define chambers and an extended radioactive source is movable to alter the source length in each chamber. Alternatively, the source is fixed relative to outer electrodes but the central electrode may be adjusted by an attached support altering the chamber dimensions and hence the length of source in each. Also disclosed are a centrally mounted source tiltable towards one or other chamber and a central electrode tiltable to alter chamber dimensions. (U.K.)

  7. Glove box chamber

    International Nuclear Information System (INIS)

    Cox, M.E.; Cox, M.E.

    1975-01-01

    An environmental chamber is described which enables an operator's hands to have direct access within the chamber without compromising a special atmosphere within such chamber. A pair of sleeves of a flexible material are sealed to the chamber around associated access apertures and project outwardly from such chamber. Each aperture is closed by a door which is openable from within the sleeve associated therewith so that upon an operator inserting his hand and arm through the sleeve, the operator can open the door to have access to the interior of the chamber. A container which is selectively separable from the remainder of the chamber is also provided to allow objects to be transferred from the chamber without such objects having to pass through the ambient atmosphere. An antechamber permitting objects to be passed directly into the chamber from the ambient atmosphere is included. (auth)

  8. Dual ionization chamber

    International Nuclear Information System (INIS)

    Mallory, J.; Turlej, Z.

    1981-01-01

    Dual ionization chambers are provided for use with an electronic smoke detector. The chambers are separated by electrically-conductive partition. A single radiation source extends through the partition into both chambers, ionizing the air in each. The mid-point current of the device may be balanced by adjusting the position of the source

  9. Atmospheric cloud physics laboratory project study

    Science.gov (United States)

    Schultz, W. E.; Stephen, L. A.; Usher, L. H.

    1976-01-01

    Engineering studies were performed for the Zero-G Cloud Physics Experiment liquid cooling and air pressure control systems. A total of four concepts for the liquid cooling system was evaluated, two of which were found to closely approach the systems requirements. Thermal insulation requirements, system hardware, and control sensor locations were established. The reservoir sizes and initial temperatures were defined as well as system power requirements. In the study of the pressure control system, fluid analyses by the Atmospheric Cloud Physics Laboratory were performed to determine flow characteristics of various orifice sizes, vacuum pump adequacy, and control systems performance. System parameters predicted in these analyses as a function of time include the following for various orifice sizes: (1) chamber and vacuum pump mass flow rates, (2) the number of valve openings or closures, (3) the maximum cloud chamber pressure deviation from the allowable, and (4) cloud chamber and accumulator pressure.

  10. Double chamber ion source

    International Nuclear Information System (INIS)

    Uman, M.F.; Winnard, J.R.; Winters, H.F.

    1978-01-01

    The ion source is comprised of two discharge chambers one of which is provided with a filament and an aperture leading into the other chamber which in turn has an extraction orifice. A low voltage arc discharge is operated in an inert gas atmosphere in the filament chamber while an arc of higher voltage is operated in the second ionization chamber which contains a vapor which will give the desired dopant ion species. The entire source is immersed in an axial magnetic field parallel to a line connecting the filament, the aperture between the two chambers and the extraction orifice. (author)

  11. Cloud Governance

    DEFF Research Database (Denmark)

    Berthing, Hans Henrik

    Denne præsentation beskriver fordele og værdier ved anvendelse af Cloud Computing. Endvidere inddrager resultater fra en række internationale analyser fra ISACA om Cloud Computing.......Denne præsentation beskriver fordele og værdier ved anvendelse af Cloud Computing. Endvidere inddrager resultater fra en række internationale analyser fra ISACA om Cloud Computing....

  12. Aerosol-cloud feedbacks in a turbulent environment: Laboratory measurements representative of conditions in boundary layer clouds

    Science.gov (United States)

    Cantrell, W. H.; Chandrakar, K. K.; Karki, S.; Kinney, G.; Shaw, R.

    2017-12-01

    Many of the climate impacts of boundary layer clouds are modulated by aerosol particles. As two examples, their interactions with incoming solar and upwelling terrestrial radiation and their propensity for precipitation are both governed by the population of aerosol particles upon which the cloud droplets formed. In turn, clouds are the primary removal mechanism for aerosol particles smaller than a few micrometers and larger than a few nanometers. Aspects of these interconnected phenomena are known in exquisite detail (e.g. Köhler theory), but other parts have not been as amenable to study in the laboratory (e.g. scavenging of aerosol particles by cloud droplets). As a complicating factor, boundary layer clouds are ubiquitously turbulent, which introduces fluctuations in the water vapor concentration and temperature, which govern the saturation ratio which mediates aerosol-cloud interactions. We have performed laboratory measurements of aerosol-cloud coupling and feedbacks, using Michigan Tech's Pi Chamber (Chang et al., 2016). In conditions representative of boundary layer clouds, our data suggest that the lifetime of most interstitial particles in the accumulation mode is governed by cloud activation - particles are removed from the Pi Chamber when they activate and settle out of the chamber as cloud droplets. As cloud droplets are removed, these interstitial particles activate until the initially polluted cloud cleans itself and all particulates are removed from the chamber. At that point, the cloud collapses. Our data also indicate that smaller particles, Dp defined through the use of the Dämkohler number, the ratio of the characteristic turbulence timescale to the cloud's microphysical response time. Chang, K., et al., 2016. A laboratory facility to study gas-aerosol-cloud interactions in a turbulent environment: The Π Chamber. Bull. Amer. Meteor. Soc., doi:10.1175/BAMS-D-15-00203.1

  13. NEG coating of the non-standard LSS vacuum chambers

    CERN Document Server

    Costa-Pinto, P

    2005-01-01

    The vacuum chambers of nearly all the warm magnets of the LHC (MBXW, MQW, MSI, MSD, etc…) will be coated with a Ti-Zr-V thin film by magnetron sputtering. The NEG coating is necessary to provide uniform pumping speed along the chambers and to suppress electron cloud instabilities and dynamic outgassing. The about 300 chambers will be coated using the existing facility, developed for the production of the standard LSS chambers, after minor modifications mainly due to the different cross sections. In order to cope with the present installation schedule, the production planning will allow processing of different families of chambers in parallel by using two or three coating systems simultaneously. After a brief introduction to the Ti-Zr-V characteristics and performances, the coating facility and strategy will be illustrated as well as the possible conflicts due to uncertainties in the planning of the experimental beam pipes and the standard LSS chambers.

  14. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  15. Prototype multiwire proportional chamber

    CERN Multimedia

    1975-01-01

    Chambers of this type were initially developed within the Alpha project (finally not approved). They were designed such to minimize the radiation length with a view to a mass spectrometer of high resolution meant to replace the Omega detector. The chambers were clearly forerunners for the (drift) chambers later built for R606 with the novel technique of crimping the wires. See also photo 7510039X.

  16. Electromagnetic reverberation chambers

    CERN Document Server

    Besnier, Philippe

    2013-01-01

    Dedicated to a complete presentation on all aspects of reverberation chambers, this book provides the physical principles behind these test systems in a very progressive manner. The detailed panorama of parameters governing the operation of electromagnetic reverberation chambers details various applications such as radiated immunity, emissivity, and shielding efficiency experiments.In addition, the reader is provided with the elements of electromagnetic theory and statistics required to take full advantage of the basic operational rules of reverberation chambers, including calibration proc

  17. DORIOT CLIMATIC CHAMBERS

    Data.gov (United States)

    Federal Laboratory Consortium — The Doriot Climatic Chambers reproduce environmental conditions occurring anywhere around the world. They provide an invaluable service by significantly reducing the...

  18. Gas microstrip chambers

    International Nuclear Information System (INIS)

    McIntyre, P.M.; Barasch, E.F.; Bowcock, T.J.V.; Demroff, H.P.; Elliott, S.M.; Howe, M.R.; Lee, B.; Mazumdar, T.K.; Pang, Y.; Smith, D.D.; Wahl, J.; Wu, Y.; Yue, W.K.; Gaedke, R.M.; Vanstraelen, G.

    1992-01-01

    The gas microstrip chamber has been developed from concept to experimental system during the past three years. A pattern of anode and grid lines are microfabricated onto a dielectric substrate and configured as a high-resolution MWPC. Four recent developments are described: Suitable plastic substrates and lithography techniques for large-area chambers; non-planar silicon-based chambers for 20 μm resolution; integrated on-board synchronous front-end electronics and data buffering; and a porous silicon active cathode for enhanced efficiency and time response. The microstrip chamber appears to be a promising technology for applications in microvertex, tracking spectrometer, muon spectrometer, and transition radiation detection. (orig.)

  19. Simulation of the electron cloud density in BEPC II

    International Nuclear Information System (INIS)

    Liu Yudong; Guo Zhiyuan; Wang Jiuqing

    2004-01-01

    Electron Cloud Instability (ECI) may take place in positron storage ring when the machine is operated with multi-bunch positron beam. According to the actual shape of the vacuum chamber in the BEPC II, a program has been developed. With the code, authors can calculate the electron density in the chamber with different length of antechamber and the different secondary electron yield respectively. By the simulation, the possibility to put clearing electrodes in the chamber to reduce the electron density in the central region of the chamber is investigated. The simulation provides meaningful and important results for the BEPC II project and electron cloud instability research

  20. Cloud Computing

    CERN Document Server

    Antonopoulos, Nick

    2010-01-01

    Cloud computing has recently emerged as a subject of substantial industrial and academic interest, though its meaning and scope is hotly debated. For some researchers, clouds are a natural evolution towards the full commercialisation of grid systems, while others dismiss the term as a mere re-branding of existing pay-per-use technologies. From either perspective, 'cloud' is now the label of choice for accountable pay-per-use access to third party applications and computational resources on a massive scale. Clouds support patterns of less predictable resource use for applications and services a

  1. An electrodeless drift chamber

    International Nuclear Information System (INIS)

    Allison, J.; Barlow, R.J.; Bowdery, C.K.; Duerdoth, I.; Rowe, P.G.

    1982-01-01

    We describe a chamber in which the drift field is controlled by the deposition of electrostatic charge on an insulating surface. The chamber operates with good efficiency and precision for observed drift distances of up to 45 cm, promises to be extremely robust and adaptable and offers a very cheap way of making particle detectors. (orig.)

  2. High resolution drift chambers

    International Nuclear Information System (INIS)

    Va'vra, J.

    1985-07-01

    High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

  3. Plastic flashtube chambers

    International Nuclear Information System (INIS)

    Frisken, W.R.

    1977-01-01

    A brief discussion is given of the use and operation of plastic flashtube chambers. Gas leaks, electric pulsing, the glow discharge, and readout methods are considered. Three distinct problems with high rate applications deal with resolving time, dead time, and polarization/neutralization of the chamber

  4. Climatic chamber ergometer

    CSIR Research Space (South Africa)

    Atkins, AR

    1968-01-01

    Full Text Available The design and calibration of an ergometer for exercising subjects during calorimetric studies in the climate chamber, are described. The ergometer is built into the climatic chamber and forms an integral part of the whole instrumentation system foe...

  5. BEBC bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Looking up into the interior of BEBC bubble chamber from the expansion cylinder. At the top of the chamber two fish-eye lenses are installed and three other fish-eye ports are blanked off. In the centre is a heat exchanger.

  6. The Mobile Chamber

    Science.gov (United States)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

    A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

  7. DELPHI time projection chamber

    CERN Multimedia

    1989-01-01

    The time projection chamber is inserted inside the central detector of the DELPHI experiment. Gas is ionised in the chamber as a charged particle passes through, producing an electric signal from which the path of the particle can be found. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  8. Cloud Cover

    Science.gov (United States)

    Schaffhauser, Dian

    2012-01-01

    This article features a major statewide initiative in North Carolina that is showing how a consortium model can minimize risks for districts and help them exploit the advantages of cloud computing. Edgecombe County Public Schools in Tarboro, North Carolina, intends to exploit a major cloud initiative being refined in the state and involving every…

  9. Cloud Control

    Science.gov (United States)

    Ramaswami, Rama; Raths, David; Schaffhauser, Dian; Skelly, Jennifer

    2011-01-01

    For many IT shops, the cloud offers an opportunity not only to improve operations but also to align themselves more closely with their schools' strategic goals. The cloud is not a plug-and-play proposition, however--it is a complex, evolving landscape that demands one's full attention. Security, privacy, contracts, and contingency planning are all…

  10. LHC Report: Out of the clouds

    CERN Multimedia

    Giovanni Rumolo, Giovanni Iadarola and Hannes Bartosik for the LHC team

    2015-01-01

    In order for the LHC to deliver intense proton beams to the experiments, operators have to perform “scrubbing” of the beam pipes. This operation is necessary to reduce the formation of electron clouds, which would generate instabilities in the colliding beams.   Electron clouds are generated in accelerators running with positively charged particles when electrons - produced by the ionisation of residual molecules in the vacuum or by the photoelectric effect from synchrotron radiation - are accelerated by the beam field and hit the surface of the vacuum chamber producing other electrons. This avalanche-like process can result in the formation of clouds of electrons. Electron clouds are detrimental to the beam for a few reasons. First, the electrons impacting the walls desorb molecules and degrade the ultra-high vacuum in the beam chamber. Furthermore, they interact electromagnetically with the beam, leading to the oscillation and expansion of the particle bunches. This increases...

  11. OPAL Jet Chamber Prototype

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  12. PS wire chamber

    CERN Multimedia

    1970-01-01

    A wire chamber used at CERN's Proton Synchrotron accelerator in the 1970s. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  13. Acoustic-Levitation Chamber

    Science.gov (United States)

    Barmatz, M. B.; Granett, D.; Lee, M. C.

    1984-01-01

    Uncontaminated environments for highly-pure material processing provided within completely sealed levitation chamber that suspends particles by acoustic excitation. Technique ideally suited for material processing in low gravity environment of space.

  14. Optical spark chamber

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    An optical spark chamber developed for use in the Omega spectrometer. On the left the supporting frame is exceptionally thin to allow low momentum particles to escape and be detected outside the magnetic field.

  15. Vacuum chamber 'bicone'

    CERN Multimedia

    1977-01-01

    This chamber is now in the National Museum of History and Technology, Smithsonian Institution, Washington, DC, USA, where it was exposed in an exhibit on the History of High Energy Accelerators (1977).

  16. Miniature ionization chamber

    International Nuclear Information System (INIS)

    Alexeev, V.I.; Emelyanov, I.Y.; Ivanov, V.M.; Konstantinov, L.V.; Lysikov, B.V.; Postnikov, V.V.; Rybakov, J.V.

    1976-01-01

    A miniature ionization chamber having a gas-filled housing which accommodates a guard electrode made in the form of a hollow perforated cylinder is described. The cylinder is electrically associated with the intermediate coaxial conductor of a triaxial cable used as the lead-in of the ionization chamber. The gas-filled housing of the ionization chamber also accommodates a collecting electrode shaped as a rod electrically connected to the center conductor of the cable and to tubular members. The rod is disposed internally of the guard electrode and is electrically connected, by means of jumpers passing through the holes in the guard electrode, to the tubular members. The tubular members embrace the guard electrode and are spaced a certain distance apart along its entire length. Arranged intermediate of these tubular members are spacers secured to the guard electrode and fixing the collecting electrode throughout its length with respect to the housing of the ionization chamber

  17. Reference ionization chamber

    International Nuclear Information System (INIS)

    Golnik, N.; Zielczynski, M.

    1999-01-01

    The paper presents the design of ionization chamber devoted for the determination of the absolute value of the absorbed dose in tissue-equivalent material. The special attention was paid to ensure that the volume of the active gas cavity was constant and well known. A specific property of the chamber design is that the voltage insulators are 'invisible' from any point of the active volume. Such configuration ensures a very good time stability of the electrical field and defines the active volume. The active volume of the chamber was determined with accuracy of 0.3%. This resulted in accuracy of 0.8% in determination of the absorbed dose in the layer of material adherent to the gas cavity. The chamber was applied for calibration purposes at radiotherapy facility in Joint Institute for Nuclear Research in Dubna (Russia) and in the calibration laboratory of the Institute of Atomic Energy in Swierk. (author)

  18. Gridded ionization chamber

    International Nuclear Information System (INIS)

    Houston, J.M.

    1977-01-01

    An improved ionization chamber type x-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is disposed adjacent the anode and is maintained at a voltsge intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting toward the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  19. ALICE Time Projection Chamber

    CERN Multimedia

    Lippmann, C

    2013-01-01

    The Time Projection Chamber (TPC) is the main device in the ALICE 'central barrel' for the tracking and identification (PID) of charged particles. It has to cope with unprecedented densities of charges particles.

  20. Cloud Computing Fundamentals

    Science.gov (United States)

    Furht, Borko

    In the introductory chapter we define the concept of cloud computing and cloud services, and we introduce layers and types of cloud computing. We discuss the differences between cloud computing and cloud services. New technologies that enabled cloud computing are presented next. We also discuss cloud computing features, standards, and security issues. We introduce the key cloud computing platforms, their vendors, and their offerings. We discuss cloud computing challenges and the future of cloud computing.

  1. Gridded Ionization Chamber

    International Nuclear Information System (INIS)

    Manero Amoros, F.

    1962-01-01

    In the present paper the working principles of a gridded ionization chamber are given, and all the different factors that determine its resolution power are analyzed in detail. One of these devices, built in the Physics Division of the JEN and designed specially for use in measurements of alpha spectroscopy, is described. finally the main applications, in which the chamber can be used, are shown. (Author) 17 refs

  2. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

    These images show real particle tracks from the annihilation of an antiproton in the 80 cm Saclay liquid hydrogen bubble chamber. A negative kaon and a neutral kaon are produced in this process, as well as a positive pion. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  3. Sleeve reaction chamber system

    Science.gov (United States)

    Northrup, M Allen [Berkeley, CA; Beeman, Barton V [San Mateo, CA; Benett, William J [Livermore, CA; Hadley, Dean R [Manteca, CA; Landre, Phoebe [Livermore, CA; Lehew, Stacy L [Livermore, CA; Krulevitch, Peter A [Pleasanton, CA

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  4. Cloud Computing

    CERN Document Server

    Baun, Christian; Nimis, Jens; Tai, Stefan

    2011-01-01

    Cloud computing is a buzz-word in today's information technology (IT) that nobody can escape. But what is really behind it? There are many interpretations of this term, but no standardized or even uniform definition. Instead, as a result of the multi-faceted viewpoints and the diverse interests expressed by the various stakeholders, cloud computing is perceived as a rather fuzzy concept. With this book, the authors deliver an overview of cloud computing architecture, services, and applications. Their aim is to bring readers up to date on this technology and thus to provide a common basis for d

  5. Dynamic consideration of smog chamber experiments

    Directory of Open Access Journals (Sweden)

    W. K. Chuang

    2017-08-01

    Full Text Available Recent studies of the α-pinene + ozone reaction that address particle nucleation show relatively high molar yields of highly oxidized multifunctional organic molecules with very low saturation concentrations that can form and grow new particles on their own. However, numerous smog-chamber experiments addressing secondary organic aerosol (SOA mass yields, interpreted via equilibrium partitioning theory, suggest that the vast majority of SOA from α-pinene is semivolatile. We explore this paradox by employing a dynamic volatility basis set (VBS model that reproduces the new-particle growth rates observed in the CLOUD experiment at CERN and then modeling SOA mass yield experiments conducted at Carnegie Mellon University (CMU. We find that the base-case simulations do overpredict observed SOA mass but by much less than an equilibrium analysis would suggest; this is because delayed condensation of vapors suppresses the apparent mass yields early in the chamber experiments. We further find that a second VBS model featuring substantial oligomerization of semivolatile monomers can match the CLOUD growth rates with substantially lower SOA mass yields; this is because the lighter monomers have a higher velocity and thus a higher condensation rate for a given mass concentration. The oligomerization simulations are a closer match to the CMU experiments than the base-case simulations, though they overpredict the observations somewhat. However, we also find that if the chemical conditions in CLOUD and the CMU chamber were identical, substantial nucleation would have occurred in the CMU experiments when in fact none occurred. This suggests that the chemical mechanisms differed in the two experiments, perhaps because the high oxidation rates in the SOA formation experiments led to rapid termination of peroxy radical chemistry.

  6. Dynamic consideration of smog chamber experiments

    Science.gov (United States)

    Chuang, Wayne K.; Donahue, Neil M.

    2017-08-01

    Recent studies of the α-pinene + ozone reaction that address particle nucleation show relatively high molar yields of highly oxidized multifunctional organic molecules with very low saturation concentrations that can form and grow new particles on their own. However, numerous smog-chamber experiments addressing secondary organic aerosol (SOA) mass yields, interpreted via equilibrium partitioning theory, suggest that the vast majority of SOA from α-pinene is semivolatile. We explore this paradox by employing a dynamic volatility basis set (VBS) model that reproduces the new-particle growth rates observed in the CLOUD experiment at CERN and then modeling SOA mass yield experiments conducted at Carnegie Mellon University (CMU). We find that the base-case simulations do overpredict observed SOA mass but by much less than an equilibrium analysis would suggest; this is because delayed condensation of vapors suppresses the apparent mass yields early in the chamber experiments. We further find that a second VBS model featuring substantial oligomerization of semivolatile monomers can match the CLOUD growth rates with substantially lower SOA mass yields; this is because the lighter monomers have a higher velocity and thus a higher condensation rate for a given mass concentration. The oligomerization simulations are a closer match to the CMU experiments than the base-case simulations, though they overpredict the observations somewhat. However, we also find that if the chemical conditions in CLOUD and the CMU chamber were identical, substantial nucleation would have occurred in the CMU experiments when in fact none occurred. This suggests that the chemical mechanisms differed in the two experiments, perhaps because the high oxidation rates in the SOA formation experiments led to rapid termination of peroxy radical chemistry.

  7. Cloud Computing

    DEFF Research Database (Denmark)

    Krogh, Simon

    2013-01-01

    with technological changes, the paradigmatic pendulum has swung between increased centralization on one side and a focus on distributed computing that pushes IT power out to end users on the other. With the introduction of outsourcing and cloud computing, centralization in large data centers is again dominating...... the IT scene. In line with the views presented by Nicolas Carr in 2003 (Carr, 2003), it is a popular assumption that cloud computing will be the next utility (like water, electricity and gas) (Buyya, Yeo, Venugopal, Broberg, & Brandic, 2009). However, this assumption disregards the fact that most IT production......), for instance, in establishing and maintaining trust between the involved parties (Sabherwal, 1999). So far, research in cloud computing has neglected this perspective and focused entirely on aspects relating to technology, economy, security and legal questions. While the core technologies of cloud computing (e...

  8. Mobile Clouds

    DEFF Research Database (Denmark)

    Fitzek, Frank; Katz, Marcos

    A mobile cloud is a cooperative arrangement of dynamically connected communication nodes sharing opportunistic resources. In this book, authors provide a comprehensive and motivating overview of this rapidly emerging technology. The book explores how distributed resources can be shared by mobile...... users in very different ways and for various purposes. The book provides many stimulating examples of resource-sharing applications. Enabling technologies for mobile clouds are also discussed, highlighting the key role of network coding. Mobile clouds have the potential to enhance communications...... performance, improve utilization of resources and create flexible platforms to share resources in very novel ways. Energy efficient aspects of mobile clouds are discussed in detail, showing how being cooperative can bring mobile users significant energy saving. The book presents and discusses multiple...

  9. Wire chambers: Trends and alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Regler, Meinhard

    1992-05-15

    The subtitle of this year's Vienna Wire Chamber Conference - 'Recent Trends and Alternative Techniques' - signalled that it covered a wide range of science and technology. While an opening Vienna talk by wire chamber pioneer Georges Charpak many years ago began 'Les funerailles des chambres a fils (the burial of wire chambers)', the contrary feeling this year was that wire chambers are very much alive!.

  10. DELPHI Barrel Muon Chamber Module

    CERN Multimedia

    1989-01-01

    The module was used as part of the muon identification system on the barrel of the DELPHI detector at LEP, and was in active use from 1989 to 2000. The module consists of 7 individual muons chambers arranged in 2 layers. Chambers in the upper layer are staggered by half a chamber width with respect to the lower layer. Each individual chamber is a drift chamber consisting of an anode wire, 47 microns in diameter, and a wrapped copper delay line. Each chamber provided 3 signal for each muon passing through the chamber, from which a 3D space-point could be reconstructed.

  11. Radon diffusion chamber

    International Nuclear Information System (INIS)

    Pretzsch, G.; Boerner, E.; Lehmann, R.; Sarenio, O.

    1986-01-01

    The invention relates to the detection of radioactive gases emitting alpha particles like radon, thoron and their alpha-decaying daughters by means of a diffusion chamber with a passive detector, preferably with a solid state track detector. In the chamber above and towards the detector there is a single metallized electret with negative polarity. The distance between electret and detector corresponds to the range of the alpha particles of radon daughters in air at the most. The electret collects the positively charged daughters and functions as surface source. The electret increases the sensitivity by the factor 4

  12. The Honeycomb Strip Chamber

    International Nuclear Information System (INIS)

    Graaf, Harry van der; Buskens, Joop; Rewiersma, Paul; Koenig, Adriaan; Wijnen, Thei

    1991-06-01

    The Honeycomb Strip Chamber (HSC) is a new position sensitive detector. It consists of a stack of folded foils, forming a rigid honeycomb structure. In the centre of each hexagonal cell a wire is strung. Conducting strips on the foils, perpendicular to the wires, pick up the induced avalanche charge. Test results of a prototype show that processing the signals form three adjacent strips nearest to the track gives a spatial resolution better than 64 μm for perpendicular incident tracks. The chamber performance is only slightly affected by a magnetic field. (author). 25 refs.; 21 figs

  13. Multiple chamber ionization detector

    International Nuclear Information System (INIS)

    Solomon, E.E.

    1982-01-01

    An ionization smoke detector employs a single radiation source in a construction comprising at least two chambers with a center or node electrode. The radioactive source is associated with this central electrode, and its positioning may be adjusted relative to the electrode to alter the proportion of the source that protrudes into each chamber. The source may also be mounted in the plane of the central electrode, and positioned relative to the center of the electrode. The central electrode or source may be made tiltable relative to the body of the detector

  14. Charpak hemispherical wire chamber

    CERN Multimedia

    1970-01-01

    pieces. Mesures are of the largest one. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  15. micro strip gas chamber

    CERN Multimedia

    1998-01-01

    About 16 000 Micro Strip Gas Chambers like this one will be used in the CMS tracking detector. They will measure the tracks of charged particles to a hundredth of a millimetre precision in the region near the collision point where the density of particles is very high. Each chamber is filled with a gas mixture of argon and dimethyl ether. Charged particles passing through ionise the gas, knocking out electrons which are collected on the aluminium strips visible under the microscope. Such detectors are being used in radiography. They give higher resolution imaging and reduce the required dose of radiation.

  16. Soft Clouding

    DEFF Research Database (Denmark)

    Søndergaard, Morten; Markussen, Thomas; Wetton, Barnabas

    2012-01-01

    Soft Clouding is a blended concept, which describes the aim of a collaborative and transdisciplinary project. The concept is a metaphor implying a blend of cognitive, embodied interaction and semantic web. Furthermore, it is a metaphor describing our attempt of curating a new semantics of sound...... archiving. The Soft Clouding Project is part of LARM - a major infrastructure combining research in and access to sound and radio archives in Denmark. In 2012 the LARM infrastructure will consist of more than 1 million hours of radio, combined with metadata who describes the content. The idea is to analyse...... the concept of ‘infrastructure’ and ‘interface’ on a creative play with the fundamentals of LARM (and any sound archive situation combining many kinds and layers of data and sources). This paper will present and discuss the Soft clouding project from the perspective of the three practices and competencies...

  17. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  18. Heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    The CERN Heavy liquid bubble chamber being installed in the north experimental hall at the PS. On the left, the 1180 litre body; in the centre the magnet, which can produce a field of 26 800 gauss; on the right the expansion mechanism.

  19. The KLOE drift chamber

    International Nuclear Information System (INIS)

    Ferrari, A.

    2002-01-01

    The design and construction of the large drift chamber of the KLOE experiment is presented. The track reconstruction is described, together with the calibration method and the monitoring systems. The stability of operation and the performance are studied with samples of e + e - , K S K L and K + K - events

  20. Drift chamber detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez Laso, L.

    1989-01-01

    A review of High Energy Physics detectors based on drift chambers is presented. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysied, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author)

  1. Drift Chambers detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez laso, L.

    1989-01-01

    We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs

  2. OPAL Muon Chamber

    CERN Multimedia

    OPAL was one of the 4 experiments installed at the LEP particle accelerator from 1989 to 2000. This is a slice of the outermost layer of OPAL : the muon chambers. This outside layer detects particles which are not stopped by the previous layers. These are mostly muons.

  3. Improvements in ionization chambers

    International Nuclear Information System (INIS)

    Whetten, N.R.; Zubal, C.

    1980-01-01

    A method of reducing mechanical vibrations transmitted to the parallel plate electrodes of ionization chamber x-ray detectors, commonly used in computerized x-ray axial tomography systems, is described. The metal plate cathodes and anodes are mounted in the ionizable gas on dielectric sheet insulators consisting of a composite of silicone resin and glass fibres. (UK)

  4. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  5. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  6. Ion chamber instrument

    International Nuclear Information System (INIS)

    Stephan, D.H.

    1975-01-01

    An electrical ionization chamber is described having a self-supporting wall of cellular material which is of uniform areal density and formed of material, such as foamed polystyrene, having an average effective atomic number between about 4 and about 9, and easily replaceable when on the instrument. (auth)

  7. Review of straw chambers

    International Nuclear Information System (INIS)

    Toki, W.H.

    1990-03-01

    This is a review of straw chambers used in the HRS, MAC, Mark III, CLEO, AMY, and TPC e + e - experiments. The straws are 6--8 mm in diameter, operate at 1--4 atmospheres and obtain resolutions of 45--100 microns. The designs and constructions are summarized and possible improvements discussed

  8. Liquid Wall Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  9. Wire chamber conference

    International Nuclear Information System (INIS)

    Bartl, W.; Neuhofer, G.; Regler, M.

    1986-02-01

    This booklet contains program and the abstracts of the papers presented at the conference, most of them dealing with performance testing of various types of wire chambers. The publication of proceedings is planned as a special issue of 'Nuclear instruments and methods' later on. All abstracts are in English. An author index for the book of abstracts is given. (A.N.)

  10. Cloud computing.

    Science.gov (United States)

    Wink, Diane M

    2012-01-01

    In this bimonthly series, the author examines how nurse educators can use Internet and Web-based technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes how cloud computing can be used in nursing education.

  11. Cloud Computing

    Indian Academy of Sciences (India)

    IAS Admin

    2014-03-01

    Mar 1, 2014 ... There are several types of services available on a cloud. We describe .... CPU speed has been doubling every 18 months at constant cost. Besides this ... Plain text (e.g., email) may be read by anyone who is able to access it.

  12. Phase B-final definition and preliminary design study for the initial Atmospheric Cloud Physics Laboratory (ACPL). A spacelab mission payload

    Science.gov (United States)

    1976-01-01

    Progress in the development of the Atmospheric Cloud Physics Laboratory is outlined. The fluid subsystem, aerosol generator, expansion chamber, optical system, control systems, and software are included.

  13. Multiwire proportional chamber development

    Science.gov (United States)

    Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

    1973-01-01

    The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

  14. Radial semiconductor drift chambers

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1987-01-01

    The conditions under which the energy resolution of a radial semiconductor drift chamber based detector system becomes dominated by the step noise from the detector dark current have been investigated. To minimise the drift chamber dark current attention should be paid to carrier generation at Si/SiO 2 interfaces. This consideration conflicts with the desire to reduce the signal risetime: a higher drift field for shorter signal pulses requires a larger area of SiO 2 . Calculations for the single shaping and pseudo Gaussian passive filters indicate that for the same degree of signal risetime sensitivity in a system dominated by the step noise from the detector dark current, the pseudo Gaussian filter gives only a 3% improvement in signal/noise and 12% improvement in rate capability compared with the single shaper performance. (orig.)

  15. Vienna Wire Chamber Conference

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    After those of 1978 and 1980, a third Wire Chamber Conference was held from 15-18 February in the Technical University of Vienna. Eight invited speakers covered the field from sophisticated applications in biology and medicine, via software, to the state of the art of gaseous detectors. In some forty other talks the speakers tackled in more detail the topics of gaseous detectors, calorimetry and associated electronics and software

  16. Wire chamber gases

    International Nuclear Information System (INIS)

    Va'vra, J.

    1992-04-01

    In this paper, we describe new developments in gas mixtures which have occurred during the last 3--4 years. In particular, we discuss new results on the measurement and modeling of electron drift parameters, the modeling of drift chamber resolution, measurements of primary ionization and the choice of gas for applications such as tracking, single electron detection, X-ray detection and visual imaging. In addition, new results are presented on photon feedback, breakdown and wire aging

  17. How to teach radiation by a cloud chamber

    International Nuclear Information System (INIS)

    Toda, Ichiro

    2005-01-01

    Now we use nuclear energy and take advantage of properties of radiation in many cases in our life. But curiously, background radiation isn't known to many people. And they believe that even if it is only a few level of radiation, it is dangerous for our health. I think the education about background radiation is very important and effective to understand radiation. (author)

  18. The Mystery “Well”: A Natural Cloud Chamber?

    Czech Academy of Sciences Publication Activity Database

    Hovorka, J.; Holub, R.F.; Ždímal, Vladimír; Bendl, J.; Hopke, P.K.

    2015-01-01

    Roč. 81, MAR 2015 (2015), s. 70-74 ISSN 0021-8502 Institutional support: RVO:67985858 Keywords : underground spaces * aerosol * precipitation Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.278, year: 2015

  19. Proton Linear Energy Transfer measurement using Emulsion Cloud Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae-ik [Proton Therapy Center, National Cancer Center (Korea, Republic of); Division of Heavy Ion Clinical Research, Korea Institute of Radiological & Medical Sciences (KIRAMS), Seoul (Korea, Republic of); Park, Seyjoon [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul (Korea, Republic of); Kim, Haksoo; Kim, Meyoung [Proton Therapy Center, National Cancer Center (Korea, Republic of); Jeong, Chiyoung [Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Cho, Sungkoo [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul (Korea, Republic of); Lim, Young Kyung; Shin, Dongho [Proton Therapy Center, National Cancer Center (Korea, Republic of); Lee, Se Byeong, E-mail: sblee@ncc.re.kr [Proton Therapy Center, National Cancer Center (Korea, Republic of); Morishima, Kunihiro; Naganawa, Naotaka; Sato, Osamu [Department of Physics, Nagoya University, Nagoya (Japan); Kwak, Jungwon [Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, Sung Hyun [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon (Korea, Republic of); Cho, Jung Sook [Department of refinement education, Dongseo University, Busan (Korea, Republic of); Ahn, Jung Keun [Department of Physics, Korea University, Seoul (Korea, Republic of); Kim, Ji Hyun; Yoon, Chun Sil [Gyeongsang National University, Jinju (Korea, Republic of); Incerti, Sebastien [CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université Bordeaux 1, CENBG, UMR 5797, F-33170 Gradignan (France)

    2015-04-15

    This study proposes to determine the correlation between the Volume Pulse Height (VPH) measured by nuclear emulsion and Linear Energy Transfer (LET) calculated by Monte Carlo simulation based on Geant4. The nuclear emulsion was irradiated at the National Cancer Center (NCC) with a therapeutic proton beam and was installed at 5.2 m distance from the beam nozzle structure with various thicknesses of water-equivalent material (PMMA) blocks to position with specific positions along the Bragg curve. After the beam exposure and development of the emulsion films, the films were scanned by S-UTS developed in Nagoya University. The proton tracks in the scanned films were reconstructed using the ‘NETSCAN’ method. Through this procedure, the VPH can be derived from each reconstructed proton track at each position along the Bragg curve. The VPH value indicates the magnitude of energy loss in proton track. By comparison with the simulation results obtained using Geant4, we found the correlation between the LET calculated by Monte Carlo simulation and the VPH measured by the nuclear emulsion.

  20. Proton Linear Energy Transfer measurement using Emulsion Cloud Chamber

    International Nuclear Information System (INIS)

    Shin, Jae-ik; Park, Seyjoon; Kim, Haksoo; Kim, Meyoung; Jeong, Chiyoung; Cho, Sungkoo; Lim, Young Kyung; Shin, Dongho; Lee, Se Byeong; Morishima, Kunihiro; Naganawa, Naotaka; Sato, Osamu; Kwak, Jungwon; Kim, Sung Hyun; Cho, Jung Sook; Ahn, Jung Keun; Kim, Ji Hyun; Yoon, Chun Sil; Incerti, Sebastien

    2015-01-01

    This study proposes to determine the correlation between the Volume Pulse Height (VPH) measured by nuclear emulsion and Linear Energy Transfer (LET) calculated by Monte Carlo simulation based on Geant4. The nuclear emulsion was irradiated at the National Cancer Center (NCC) with a therapeutic proton beam and was installed at 5.2 m distance from the beam nozzle structure with various thicknesses of water-equivalent material (PMMA) blocks to position with specific positions along the Bragg curve. After the beam exposure and development of the emulsion films, the films were scanned by S-UTS developed in Nagoya University. The proton tracks in the scanned films were reconstructed using the ‘NETSCAN’ method. Through this procedure, the VPH can be derived from each reconstructed proton track at each position along the Bragg curve. The VPH value indicates the magnitude of energy loss in proton track. By comparison with the simulation results obtained using Geant4, we found the correlation between the LET calculated by Monte Carlo simulation and the VPH measured by the nuclear emulsion

  1. Proton Linear Energy Transfer measurement using Emulsion Cloud Chamber

    Science.gov (United States)

    Shin, Jae-ik; Park, Seyjoon; Kim, Haksoo; Kim, Meyoung; Jeong, Chiyoung; Cho, Sungkoo; Lim, Young Kyung; Shin, Dongho; Lee, Se Byeong; Morishima, Kunihiro; Naganawa, Naotaka; Sato, Osamu; Kwak, Jungwon; Kim, Sung Hyun; Cho, Jung Sook; Ahn, Jung Keun; Kim, Ji Hyun; Yoon, Chun Sil; Incerti, Sebastien

    2015-04-01

    This study proposes to determine the correlation between the Volume Pulse Height (VPH) measured by nuclear emulsion and Linear Energy Transfer (LET) calculated by Monte Carlo simulation based on Geant4. The nuclear emulsion was irradiated at the National Cancer Center (NCC) with a therapeutic proton beam and was installed at 5.2 m distance from the beam nozzle structure with various thicknesses of water-equivalent material (PMMA) blocks to position with specific positions along the Bragg curve. After the beam exposure and development of the emulsion films, the films were scanned by S-UTS developed in Nagoya University. The proton tracks in the scanned films were reconstructed using the 'NETSCAN' method. Through this procedure, the VPH can be derived from each reconstructed proton track at each position along the Bragg curve. The VPH value indicates the magnitude of energy loss in proton track. By comparison with the simulation results obtained using Geant4, we found the correlation between the LET calculated by Monte Carlo simulation and the VPH measured by the nuclear emulsion.

  2. Double chambered right ventricle

    International Nuclear Information System (INIS)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung

    1983-01-01

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure

  3. Double chambered right ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1983-12-15

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure.

  4. Argus drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, M; Nagovizin, V; Hasemann, H; Michel, E; Schmidt-Parzefall, W; Wurth, R; Kim, P

    1983-11-15

    The ARGUS detector came into operation at the DORIS-II e/sup +/s/sup -/ storage ring at the end of 1982. Its two meter long drift chamber contains 5940 sense and 24588 field wires organized in uniform 18x18.8 mm/sup 2/ drift cells filling the whole volume. These cells form 36 layers, 18 of which provide stereo views. Each sense wire is equipped with a single hit TDC and ADC for coordinate and dE/dx measurements. The chamber is operated with propane to improve momentum and dE/dx resolution. The drift chamber design and initial performance are presented. With a very crude space-time relation approximation and without all the necessary corrections applied a spatial resolution of about 200 ..mu..m was obtained for half of the drift cell volume. Further corrections should improve this result. An intrinsic dE/dx resolution of 4.2% and an actual resolution of 5% were obtained for cosmic muons and also for Bhabha scattered electrons. An actual dE/dx resolution of 5.6% was obtained for pions from e/sup +/e/sup -/ annihilation data with almost no track selection. A relativistic rise of 30% was observed in good agreement with theory. The long-term stability is still to be investigated.

  5. Argus target chamber

    International Nuclear Information System (INIS)

    Rienecker, F. Jr.; Glaros, S.S.; Kobierecki, M.

    1975-01-01

    A target chamber for application in the laser fusion program must satisfy some very basic requirements. (1) Provide a vacuum on the order of 10 -6 torr. (2) Support a microscopically small target in a fixed point in space and verify its location within 5 micrometers. (3) Contain an adjustable beam focusing system capable of delivering a number of laser beams onto the target simultaneously, both in time and space. (4) Provide access for diagnostics to evaluate the results of target irradiation. (5) Have flexibility to allow changes in targets, focusing optics and number of beams. The ARGUS laser which is now under construction at LLL will have a target chamber which meets these requirements in a simple economic manner. The chamber and auxiliary equipment are described, with reference to two double beam focusing systems; namely, lenses and ellipsoidal mirrors. Provision is made for future operation with four beams, using ellipsoidal mirrors for two-sided illumination and lens systems for tetragonal and tetrahedral irradiation

  6. Wire chambers: Trends and alternatives

    International Nuclear Information System (INIS)

    Regler, Meinhard

    1992-01-01

    The subtitle of this year's Vienna Wire Chamber Conference - 'Recent Trends and Alternative Techniques' - signalled that it covered a wide range of science and technology. While an opening Vienna talk by wire chamber pioneer Georges Charpak many years ago began 'Les funerailles des chambres a fils (the burial of wire chambers)', the contrary feeling this year was that wire chambers are very much alive!

  7. Criteria for controlled atmosphere chambers

    International Nuclear Information System (INIS)

    Robinson, J.N.

    1980-03-01

    The criteria for design, construction, and operation of controlled atmosphere chambers intended for service at ORNL are presented. Classification of chambers, materials for construction, design criteria, design, controlled atmosphere chamber systems, and operating procedures are presented. ORNL Safety Manual Procedure 2.1; ORNL Health Physics Procedure Manual Appendix A-7; and Design of Viewing Windows are included in 3 appendices

  8. Improved Cloud Condensation Nucleus Spectrometer

    Science.gov (United States)

    Leu, Ming-Taun

    2010-01-01

    An improved thermal-gradient cloud condensation nucleus spectrometer (CCNS) has been designed to provide several enhancements over prior thermal- gradient counters, including fast response and high-sensitivity detection covering a wide range of supersaturations. CCNSs are used in laboratory research on the relationships among aerosols, supersaturation of air, and the formation of clouds. The operational characteristics of prior counters are such that it takes long times to determine aerosol critical supersaturations. Hence, there is a need for a CCNS capable of rapid scanning through a wide range of supersaturations. The present improved CCNS satisfies this need. The improved thermal-gradient CCNS (see Figure 1) incorporates the following notable features: a) The main chamber is bounded on the top and bottom by parallel thick copper plates, which are joined by a thermally conductive vertical wall on one side and a thermally nonconductive wall on the opposite side. b) To establish a temperature gradient needed to establish a supersaturation gradient, water at two different regulated temperatures is pumped through tubes along the edges of the copper plates at the thermally-nonconductive-wall side. Figure 2 presents an example of temperature and supersaturation gradients for one combination of regulated temperatures at the thermally-nonconductive-wall edges of the copper plates. c) To enable measurement of the temperature gradient, ten thermocouples are cemented to the external surfaces of the copper plates (five on the top plate and five on the bottom plate), spaced at equal intervals along the width axis of the main chamber near the outlet end. d) Pieces of filter paper or cotton felt are cemented onto the interior surfaces of the copper plates and, prior to each experimental run, are saturated with water to establish a supersaturation field inside the main chamber. e) A flow of monodisperse aerosol and a dilution flow of humid air are introduced into the main

  9. Cloud management and security

    CERN Document Server

    Abbadi, Imad M

    2014-01-01

    Written by an expert with over 15 years' experience in the field, this book establishes the foundations of Cloud computing, building an in-depth and diverse understanding of the technologies behind Cloud computing. In this book, the author begins with an introduction to Cloud computing, presenting fundamental concepts such as analyzing Cloud definitions, Cloud evolution, Cloud services, Cloud deployment types and highlighting the main challenges. Following on from the introduction, the book is divided into three parts: Cloud management, Cloud security, and practical examples. Part one presents the main components constituting the Cloud and federated Cloud infrastructure(e.g., interactions and deployment), discusses management platforms (resources and services), identifies and analyzes the main properties of the Cloud infrastructure, and presents Cloud automated management services: virtual and application resource management services. Part two analyzes the problem of establishing trustworthy Cloud, discuss...

  10. Cloud time

    CERN Document Server

    Lockwood, Dean

    2012-01-01

    The ‘Cloud’, hailed as a new digital commons, a utopia of collaborative expression and constant connection, actually constitutes a strategy of vitalist post-hegemonic power, which moves to dominate immanently and intensively, organizing our affective political involvements, instituting new modes of enclosure, and, crucially, colonizing the future through a new temporality of control. The virtual is often claimed as a realm of invention through which capitalism might be cracked, but it is precisely here that power now thrives. Cloud time, in service of security and profit, assumes all is knowable. We bear witness to the collapse of both past and future virtuals into a present dedicated to the exploitation of the spectres of both.

  11. The Case Of The Elusive Electron Cloud

    CERN Multimedia

    2001-01-01

    Fig. 1 Electron cloud following a controlled beam bump. 'Elementary my dear Watson, you see this footprint proves it was the butler in the foyer with the butcher's knife.' Sir Arthur Conan Doyle's Sherlock Holmes may at first appear a long way from particle physics, but first appearances are often deceiving... The mysteries behind the 'Electron Cloud Effect', a dangerous electron multiplication phenomenon which could possibly limit the LHC's performance, have recently been under a detective level investigation that is yielding data that would make even the valiant Holmes balk. The electron cloud, a group of free floating electrons in the collider, is caused by electron multiplication on the vacuum chamber wall and was first observed in 1976. The cloud that develops is a serious problem because it can lead to beam growth, increased gas release from the collider surface, and a supplementary heat load to the LHC cryogenic system. The phenomenon has been observed since 1999 in the SPS where unexpected pressure...

  12. Vacuum Chambers for LEP sections

    CERN Multimedia

    1983-01-01

    The picture shows sections of the LEP vacuum chambers to be installed in the dipole magnets (left) and in the quadrupoles (right). The dipole chamber has three channels: the beam chamber, the pumping duct where the NEG (non-evaporabe getter) is installed and the water channel for cooling (on top in the picture). The pumping duct is connected to the beam chamber through holes in the separating wall. The thick lead lining to shield radiation can also be seen. These chambers were manufactured as extruded aluminium alloy profiles.

  13. Review of wire chamber aging

    International Nuclear Information System (INIS)

    Va'Vra, J.

    1986-02-01

    This paper makes an overview of the wire chamber aging problems as a function of various chamber design parameters. It emphasizes the chemistry point of view and many examples are drawn from the plasma chemistry field as a guidance for a possible effort in the wire chamber field. The paper emphasizes the necessity of variable tuning, the importance of purity of the wire chamber environment, as well as it provides a practical list of presently known recommendations. In addition, several models of the wire chamber aging are qualitatively discussed. The paper is based on a summary talk given at the Wire Chamber Aging Workshop held at LBL, Berkeley on January 16-17, 1986. Presented also at Wire Chamber Conference, Vienna, February 25-28, 1986. 74 refs., 18 figs., 11 tabs

  14. Space plasma simulation chamber

    International Nuclear Information System (INIS)

    1986-01-01

    Scientific results of experiments and tests of instruments performed with the Space Plasma Simulation Chamber and its facility are reviewed in the following six categories. 1. Tests of instruments on board rockets, satellites and balloons. 2. Plasma wave experiments. 3. Measurements of plasma particles. 4. Optical measurements. 5. Plasma production. 6. Space plasms simulations. This facility has been managed under Laboratory Space Plasma Comittee since 1969 and used by scientists in cooperative programs with universities and institutes all over country. A list of publications is attached. (author)

  15. Stability of Streamer Chamber

    Science.gov (United States)

    Wada, Toshiaki; Ogawa, Masato; Takahashi, Kaoru; Sugiyama, Tsunetoshi; Kobayashi, Shigeharu; Kohno, Hirobumi

    1982-08-01

    The quality of tracks obtained from a streamer chamber is studied through the measurement of the streamer brightness. The stability of streamer tracks depends on the value of the high voltage applied and its shape. By using a single conical-type spark gap as the pulse shaper, stable brightness of the streamer tracks is attained. The data on the streamer brightness are compared with the result by Bulos et al. and it is found that the brightness is more strongly affected by field parameters than in their result.

  16. Stability of streamer chamber

    International Nuclear Information System (INIS)

    Wada, Toshiaki; Ogawa, Masato; Takahashi, Kaoru; Sugiyama, Tsunetoshi; Kobayashi, Shigeharu; Kohno, Hirobumi.

    1982-01-01

    The quality of tracks obtained from a streamer chamber is studied through the measurement of the streamer brightness. The stability of streamer tracks depends on the value of the high voltage applied and its shape. By using a single conical-type spark gap as the pulse shaper, stable brightness of the streamer tracks is attained. The data on the streamer brightness are compared with the result by Bulos et al. and it is found that the brightness is more strongly affected by field parameters than in their result. (author)

  17. Essentials of cloud computing

    CERN Document Server

    Chandrasekaran, K

    2014-01-01

    ForewordPrefaceComputing ParadigmsLearning ObjectivesPreambleHigh-Performance ComputingParallel ComputingDistributed ComputingCluster ComputingGrid ComputingCloud ComputingBiocomputingMobile ComputingQuantum ComputingOptical ComputingNanocomputingNetwork ComputingSummaryReview PointsReview QuestionsFurther ReadingCloud Computing FundamentalsLearning ObjectivesPreambleMotivation for Cloud ComputingThe Need for Cloud ComputingDefining Cloud ComputingNIST Definition of Cloud ComputingCloud Computing Is a ServiceCloud Computing Is a Platform5-4-3 Principles of Cloud computingFive Essential Charact

  18. LS1 Report: the clouds are lifting

    CERN Multimedia

    Anaïs Schaeffer

    2014-01-01

    To combat the problem of electron clouds, which perturbate the environment of the particle beams in our accelerators, the Vacuum team have turned to amorphous carbon. This material is being applied to the interior of 16 magnets in the SPS during LS1 and will help prevent the formation of the secondary particles which are responsible for these clouds.   This photo shows the familiar coils of an SPS dipole magnet in brown. The vacuum chamber is the metallic rectangular part in the centre. The small wheeled device you can see in the vacuum chamber carries the hollow cathodes  along the length of the chamber. When a particle beam circulates at high energy in a vacuum chamber, it unavoidably generates secondary particles. These include electrons produced by the ionisation of residual molecules in the vacuum or indirectly generated by synchrotron radiation. When these electrons hit the surface of the vacuum chamber, they produce other electrons which, through an avalanche-like process, re...

  19. Council Chamber exhibition

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    To complete the revamp of CERN’s Council Chamber, a new exhibition is being installed just in time for the June Council meetings.   Panels will showcase highlights of CERN’s history, using some of the content prepared for the exhibitions marking 50 years of the PS, which were displayed in the main building last November. The previous photo exhibition in the Council Chamber stopped at the 1970s. To avoid the new panels becoming quickly out of date, photos are grouped together around specific infrastructures, rather than following a classic time-line. “We have put the focus on the accelerators – the world-class facilities that CERN has been offering researchers over the years, from the well-known large colliders to the lesser-known smaller facilities,” says Emma Sanders, who worked on the content. The new exhibition will be featured in a future issue of the Bulletin with photos and an interview with Fabienne Marcastel, designer of the exhibit...

  20. Cardiac chamber scintiscanning

    International Nuclear Information System (INIS)

    Goretzki, G.

    1981-01-01

    The two methods of cardiac chamber scintiscanning, i.e. 'first pass' and 'ECG-triggered' examinations, are explained and compared. Two tables indicate the most significant radiation doses of the applied radio tracers, i.e. 99m-Tc-pertechnetate and 99m-Tc-HSA, to which a patient is exposed. These averaged values are calculated from various data given in specialised literature. On the basis of data given in literature, an effective half-life of approximately 5 hours in the intravascular space was calculated for the erythrocytes labelled with technetium 99m. On this basis, the radiation doses for the patients due to 99m-Tc-labelled erythrocytes are estimated. The advantages and disadvantages of the two methods applied for cardiac chamber scintiscanning are put into contrast and compared with the advantages and disadvantages of the quantitative X-ray cardiography of the left heart. The still existing problems connected with the assessment of ECG-triggered images are discussed in detail. The author performed investigations of his own, which concerned the above-mentioned problems. (orig./MG) [de

  1. Results from the CERN pilot CLOUD experiment

    DEFF Research Database (Denmark)

    Duplissy, J.; Enghoff, Martin Andreas Bødker; Aplin, K. L.

    2009-01-01

    is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts...... are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely...

  2. Cloud Computing, Tieto Cloud Server Model

    OpenAIRE

    Suikkanen, Saara

    2013-01-01

    The purpose of this study is to find out what is cloud computing. To be able to make wise decisions when moving to cloud or considering it, companies need to understand what cloud is consists of. Which model suits best to they company, what should be taken into account before moving to cloud, what is the cloud broker role and also SWOT analysis of cloud? To be able to answer customer requirements and business demands, IT companies should develop and produce new service models. IT house T...

  3. Blue skies for CLOUD

    CERN Multimedia

    2006-01-01

    Through the recently approved CLOUD experiment, CERN will soon be contributing to climate research. Tests are being performed on the first prototype of CLOUD, an experiment designed to assess cosmic radiation influence on cloud formation.

  4. Moving towards Cloud Security

    OpenAIRE

    Edit Szilvia Rubóczki; Zoltán Rajnai

    2015-01-01

    Cloud computing hosts and delivers many different services via Internet. There are a lot of reasons why people opt for using cloud resources. Cloud development is increasing fast while a lot of related services drop behind, for example the mass awareness of cloud security. However the new generation upload videos and pictures without reason to a cloud storage, but only few know about data privacy, data management and the proprietary of stored data in the cloud. In an enterprise environment th...

  5. Diogene pictorial drift chamber

    International Nuclear Information System (INIS)

    Gosset, J.

    1984-01-01

    A pictorial drift chamber, called DIOGENE, has been installed at Saturne in order to study central collisions of high energy heavy ions. It has been adapted from the JADE internal detector, with two major differences to be taken into account. First, the center-of-mass of these collisions is not identical to the laboratory reference frame. Second, the energy loss and the momentum ranges of the particles to be detected are different from the ones in JADE. It was also tried to keep the cost as small as possible, hence the choice of minimum size and minimum number of sensitive wires. Moreover the wire planes are shifted from the beam axis: this trick helps very much to quickly reject the bad tracks caused by the ambiguity of measuring drift distances (positive or negative) through times (always positive)

  6. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  7. Simulation of chamber experiments

    International Nuclear Information System (INIS)

    Ivanov, V.G.

    1981-01-01

    The description of the system of computer simulation of experiments conducted by means of track detectors with film data output is given. Considered is the principle of organization of computer model of the chamber experiment comprising the following stages: generation of events, generation of measurements, ge-- neration of scanning results, generation of distorbions, generated data calibration, filtration, events reconstruction, kinematic identification, total results tape formation, analysis of the results. Generation programs are formed as special RAM-files, where the RAM-file is the text of the program written in FORTRAN and divided into structural elements. All the programs are a ''part of the ''Hydra'' system. The system possibilities are considered on the base of the CDSC-6500 computer. The five-beam event generation, creation data structure for identification and calculation by the kinematic program take about 1s of CDC-6500 computer time [ru

  8. Nucleation in bubble chambers

    International Nuclear Information System (INIS)

    Harigel, G.G.

    1988-01-01

    Various sources and mechanisms for bubble formation in superheated liquids are discussed. Bubble chambers can be filled with a great variety of liquids, such as e.g. the cryogenic liquids hydrogen, deuterium, neon, neon/hydrogen mixtures, argon, nitrogen, argon/nitrogen mixtures, or the warm liquids propane and various Freon like Freon-13B1. The superheated state is normally achieved by a rapid movement of an expansion piston or membrane, but can also be produced by standing ultrasonic waves, shock waves, or putting liquids under tension. Bubble formation can be initiated by ionizing particles, by intense (laser) light, or on rough surfaces. The creation of embryonic bubbles is not completely understood, but the macroscopic growth and condensation can be calculated, allowing to estimate the dynamic heat load [fr

  9. Electron Cloud Effect in the Linear Colliders

    International Nuclear Information System (INIS)

    Pivi, M

    2004-01-01

    Beam induced multipacting, driven by the electric field of successive positively charged bunches, may arise from a resonant motion of electrons, generated by secondary emission, bouncing back and forth between opposite walls of the vacuum chamber. The electron-cloud effect (ECE) has been observed or is expected at many storage rings [1]. In the beam pipe of the Damping Ring (DR) of a linear collider, an electron cloud is produced initially by ionization of the residual gas and photoelectrons from the synchrotron radiation. The cloud is then sustained by secondary electron emission. This electron cloud can reach equilibrium after the passage of only a few bunches. The electron-cloud effect may be responsible for collective effects as fast coupled-bunch and single-bunch instability, emittance blow-up or incoherent tune shift when the bunch current exceeds a certain threshold, accompanied by a large number of electrons in the vacuum chamber. The ECE was identified as one of the most important R and D topics in the International Linear Collider Report [2]. Systematic studies on the possible electron-cloud effect have been initiated at SLAC for the GLC/NLC and TESLA linear colliders, with particular attention to the effect in the positron main damping ring (MDR) and the positron Low Emittance Transport which includes the bunch compressor system (BCS), the main linac, and the beam delivery system (BDS). We present recent computer simulation results for the main features of the electron cloud generation in both machine designs. Thus, single and coupled-bunch instability thresholds are estimated for the GLC/NLC design

  10. Cloud-Top Entrainment in Stratocumulus Clouds

    Science.gov (United States)

    Mellado, Juan Pedro

    2017-01-01

    Cloud entrainment, the mixing between cloudy and clear air at the boundary of clouds, constitutes one paradigm for the relevance of small scales in the Earth system: By regulating cloud lifetimes, meter- and submeter-scale processes at cloud boundaries can influence planetary-scale properties. Understanding cloud entrainment is difficult given the complexity and diversity of the associated phenomena, which include turbulence entrainment within a stratified medium, convective instabilities driven by radiative and evaporative cooling, shear instabilities, and cloud microphysics. Obtaining accurate data at the required small scales is also challenging, for both simulations and measurements. During the past few decades, however, high-resolution simulations and measurements have greatly advanced our understanding of the main mechanisms controlling cloud entrainment. This article reviews some of these advances, focusing on stratocumulus clouds, and indicates remaining challenges.

  11. Cloud Infrastructure & Applications - CloudIA

    Science.gov (United States)

    Sulistio, Anthony; Reich, Christoph; Doelitzscher, Frank

    The idea behind Cloud Computing is to deliver Infrastructure-as-a-Services and Software-as-a-Service over the Internet on an easy pay-per-use business model. To harness the potentials of Cloud Computing for e-Learning and research purposes, and to small- and medium-sized enterprises, the Hochschule Furtwangen University establishes a new project, called Cloud Infrastructure & Applications (CloudIA). The CloudIA project is a market-oriented cloud infrastructure that leverages different virtualization technologies, by supporting Service-Level Agreements for various service offerings. This paper describes the CloudIA project in details and mentions our early experiences in building a private cloud using an existing infrastructure.

  12. Silicon Photonics Cloud (SiCloud)

    DEFF Research Database (Denmark)

    DeVore, P. T. S.; Jiang, Y.; Lynch, M.

    2015-01-01

    Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths.......Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths....

  13. The little holographic bubble chambers

    International Nuclear Information System (INIS)

    Herve, A.

    1983-01-01

    The lifetime study of the charmed particles has readvanced the idea to use holography for the little fast-cycle bubble chambers. A pilot experiment has been realised in 1982 with a little bubble chamber filled up with freon-115. 40000 holograms have been recorded [fr

  14. National Ignition Facility Target Chamber

    International Nuclear Information System (INIS)

    Wavrik, R W; Cox, J R; Fleming, P J

    2000-01-01

    On June 11, 1999 the Department of Energy dedicated the single largest piece of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The ten (10) meter diameter aluminum target high vacuum chamber will serve as the working end of the largest laser in the world. The output of 192 laser beams will converge at the precise center of the chamber. The laser beams will enter the chamber in two by two arrays to illuminate 10 millimeter long gold cylinders called hohlraums enclosing 2 millimeter capsule containing deuterium, tritium and isotopes of hydrogen. The two isotopes will fuse, thereby creating temperatures and pressures resembling those found only inside stars and in detonated nuclear weapons, but on a minute scale. The NIF Project will serve as an essential facility to insure safety and reliability of our nation's nuclear arsenal as well as demonstrating inertial fusion's contribution to creating electrical power. The paper will discuss the requirements that had to be addressed during the design, fabrication and testing of the target chamber. A team from Sandia National Laboratories (SNL) and LLNL with input from industry performed the configuration and basic design of the target chamber. The method of fabrication and construction of the aluminum target chamber was devised by Pitt-Des Moines, Inc. (PDM). PDM also participated in the design of the chamber in areas such as the Target Chamber Realignment and Adjustment System, which would allow realignment of the sphere laser beams in the event of earth settlement or movement from a seismic event. During the fabrication of the target chamber the sphericity tolerances had to be addressed for the individual plates. Procedures were developed for forming, edge preparation and welding of individual plates. Construction plans were developed to allow the field construction of the target chamber to occur parallel to other NIF construction activities. This was

  15. The CLEO III drift chamber

    CERN Document Server

    Peterson, D; Briere, R A; Chen, G; Cronin-Hennessy, D; Csorna, S; Dickson, M; Dombrowski, S V; Ecklund, K M; Lyon, A; Marka, S; Meyer, T O; Patterson, J R; Sadoff, A; Thies, P; Thorndike, E H; Urner, D

    2002-01-01

    The CLEO group at the Cornell Electron Storage Ring has constructed and commissioned a new central drift chamber. With 9796 cells arranged in 47 layers ranging in radius from 13.2 to 79 cm, the new drift chamber has a smaller outer radius and fewer wires than the drift chamber it replaces, but allows the CLEO tracking system to have improved momentum resolution. Reduced scattering material in the chamber gas and in the inner skin separating the drift chamber from the silicon vertex detector provides a reduction of the multiple scattering component of the momentum resolution and an extension of the usable measurement length into the silicon. Momentum resolution is further improved through quality control in wire positioning and symmetry of the electric fields in the drift cells which have provided a reduction in the spatial resolution to 88 mu m (averaged over the full drift range).

  16. Dark matter limits froma 15 kg windowless bubble chamber

    Energy Technology Data Exchange (ETDEWEB)

    Szydagis, Matthew Mark [Univ. of Chicago, IL (United States)

    2011-03-01

    The COUPP collaboration has successfully used bubble chambers, a technology previously applied only to high-energy physics experiments, as direct dark matter detectors. It has produced the world's most stringent spin-dependent WIMP limits, and increasingly competitive spin-independent limits. These limits were achieved by capitalizing on an intrinsic rejection of the gamma background that all other direct detection experiments must address through high-density shielding and empirically-determined data cuts. The history of COUPP, including its earliest prototypes and latest results, is briefly discussed in this thesis. The feasibility of a new, windowless bubble chamber concept simpler and more inexpensive in design is discussed here as well. The dark matter limits achieved with a 15 kg windowless chamber, larger than any previous COUPP chamber (2 kg, 4 kg), are presented. Evidence of the greater radiopurity of synthetic quartz compared to natural is presented using the data from this 15 kg device, the first chamber to be made from synthetic quartz. The effective reconstruction of the three-dimensional positions of bubbles in a highly distorted optical field, with ninety-degree bottom lighting similar to cloud chamber lighting, is demonstrated. Another innovation described in this thesis is the use of the sound produced by bubbles recorded by an array of piezoelectric sensors as the primary means of bubble detection. In other COUPP chambers, cameras have been used as the primary trigger. Previous work on bubble acoustic signature differentiation using piezos is built upon in order to further demonstrate the ability to discriminate between alpha- and neutron-induced events.

  17. Dark matter limits from a 15 kg windowless bubble chamber

    International Nuclear Information System (INIS)

    Szydagis, Matthew Mark

    2010-01-01

    The COUPP collaboration has successfully used bubble chambers, a technology previously applied only to high-energy physics experiments, as direct dark matter detectors. It has produced the world's most stringent spin-dependent WIMP limits, and increasingly competitive spin-independent limits. These limits were achieved by capitalizing on an intrinsic rejection of the gamma background that all other direct detection experiments must address through high-density shielding and empirically-determined data cuts. The history of COUPP, including its earliest prototypes and latest results, is briefly discussed in this thesis. The feasibility of a new, windowless bubble chamber concept simpler and more inexpensive in design is discussed here as well. The dark matter limits achieved with a 15 kg windowless chamber, larger than any previous COUPP chamber (2 kg, 4 kg), are presented. Evidence of the greater radiopurity of synthetic quartz compared to natural is presented using the data from this 15 kg device, the first chamber to be made from synthetic quartz. The effective reconstruction of the three-dimensional positions of bubbles in a highly distorted optical field, with ninety-degree bottom lighting similar to cloud chamber lighting, is demonstrated. Another innovation described in this thesis is the use of the sound produced by bubbles recorded by an array of piezoelectric sensors as the primary means of bubble detection. In other COUPP chambers, cameras have been used as the primary trigger. Previous work on bubble acoustic signature differentiation using piezos is built upon in order to further demonstrate the ability to discriminate between alpha- and neutron-induced events.

  18. Vertical microphysical profiles of convective clouds as a tool for obtaining aerosol cloud-mediated climate forcings

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfeld, Daniel [Hebrew Univ. of Jerusalem (Israel)

    2015-12-23

    Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Developing and validating this methodology was possible thanks to the ASR/ARM measurements of CCN and vertical updraft profiles. Validation against ground-based CCN instruments at the ARM sites in Oklahoma, Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25º restricts the satellite coverage to ~25% of the world area in a single day. This methodology will likely allow overcoming the challenge of quantifying the aerosol indirect effect and facilitate a substantial reduction of the uncertainty in anthropogenic climate forcing.

  19. The CLOUD experiment

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    The Cosmics Leaving Outdoor Droplets (CLOUD) experiment as shown by Jasper Kirkby (spokesperson). Kirkby shows a sketch to illustrate the possible link between galactic cosmic rays and cloud formations. The CLOUD experiment uses beams from the PS accelerator at CERN to simulate the effect of cosmic rays on cloud formations in the Earth's atmosphere. It is thought that cosmic ray intensity is linked to the amount of low cloud cover due to the formation of aerosols, which induce condensation.

  20. BUSINESS INTELLIGENCE IN CLOUD

    OpenAIRE

    Celina M. Olszak

    2014-01-01

    . The paper reviews and critiques current research on Business Intelligence (BI) in cloud. This review highlights that organizations face various challenges using BI cloud. The research objectives for this study are a conceptualization of the BI cloud issue, as well as an investigation of some benefits and risks from BI cloud. The study was based mainly on a critical analysis of literature and some reports on BI cloud using. The results of this research can be used by IT and business leaders ...

  1. Cloud Robotics Platforms

    Directory of Open Access Journals (Sweden)

    Busra Koken

    2015-01-01

    Full Text Available Cloud robotics is a rapidly evolving field that allows robots to offload computation-intensive and storage-intensive jobs into the cloud. Robots are limited in terms of computational capacity, memory and storage. Cloud provides unlimited computation power, memory, storage and especially collaboration opportunity. Cloud-enabled robots are divided into two categories as standalone and networked robots. This article surveys cloud robotic platforms, standalone and networked robotic works such as grasping, simultaneous localization and mapping (SLAM and monitoring.

  2. Cloud Processed CCN Suppress Stratus Cloud Drizzle

    Science.gov (United States)

    Hudson, J. G.; Noble, S. R., Jr.

    2017-12-01

    Conversion of sulfur dioxide to sulfate within cloud droplets increases the sizes and decreases the critical supersaturation, Sc, of cloud residual particles that had nucleated the droplets. Since other particles remain at the same sizes and Sc a size and Sc gap is often observed. Hudson et al. (2015) showed higher cloud droplet concentrations (Nc) in stratus clouds associated with bimodal high-resolution CCN spectra from the DRI CCN spectrometer compared to clouds associated with unimodal CCN spectra (not cloud processed). Here we show that CCN spectral shape (bimodal or unimodal) affects all aspects of stratus cloud microphysics and drizzle. Panel A shows mean differential cloud droplet spectra that have been divided according to traditional slopes, k, of the 131 measured CCN spectra in the Marine Stratus/Stratocumulus Experiment (MASE) off the Central California coast. K is generally high within the supersaturation, S, range of stratus clouds (< 0.5%). Because cloud processing decreases Sc of some particles, it reduces k. Panel A shows higher concentrations of small cloud droplets apparently grown on lower k CCN than clouds grown on higher k CCN. At small droplet sizes the concentrations follow the k order of the legend, black, red, green, blue (lowest to highest k). Above 13 µm diameter the lines cross and the hierarchy reverses so that blue (highest k) has the highest concentrations followed by green, red and black (lowest k). This reversed hierarchy continues into the drizzle size range (panel B) where the most drizzle drops, Nd, are in clouds grown on the least cloud-processed CCN (blue), while clouds grown on the most processed CCN (black) have the lowest Nd. Suppression of stratus cloud drizzle by cloud processing is an additional 2nd indirect aerosol effect (IAE) that along with the enhancement of 1st IAE by higher Nc (panel A) are above and beyond original IAE. However, further similar analysis is needed in other cloud regimes to determine if MASE was

  3. Micro plate fission chamber development

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Jiang Li; Liu Rong; Wang Dalun

    2014-01-01

    To conduct the measurement of neutron flux and the fission rate distribution at several position in assemblies, the micro plate fission chamber was designed and fabricated. Since the requirement of smaller volume and less structure material was taken into consideration, it is convinient, commercial and practical to use fission chamber to measure neutron flux in specific condition. In this paper, the structure of fission chamber and process of fabrication were introduced and performance test result was presented. The detection efficiency is 91.7%. (authors)

  4. Pelletron general purpose scattering chamber

    International Nuclear Information System (INIS)

    Chatterjee, A.; Kailas, S.; Kerekette, S.S.; Navin, A.; Kumar, Suresh

    1993-01-01

    A medium sized stainless steel scattering chamber has been constructed for nuclear scattering and reaction experiments at the 14UD pelletron accelerator facility. It has been so designed that several types of detectors, varying from small sized silicon surface barrier detectors to medium sized gas detectors and NaI detectors can be conveniently positioned inside the chamber for detection of charged particles. The chamber has been planned to perform the following types of experiments : angular distributions of elastically scattered particles, fission fragments and other charged particles, angular correlations for charged particles e.g. protons, alphas and fission fragments. (author). 2 figs

  5. Relationship between cloud radiative forcing, cloud fraction and cloud albedo, and new surface-based approach for determining cloud albedo

    OpenAIRE

    Y. Liu; W. Wu; M. P. Jensen; T. Toto

    2011-01-01

    This paper focuses on three interconnected topics: (1) quantitative relationship between surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo; (2) surfaced-based approach for measuring cloud albedo; (3) multiscale (diurnal, annual and inter-annual) variations and covariations of surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo. An analytical expression is first derived to quantify the relationship between cloud radiative forcing, cloud fractio...

  6. Cosmic rays,Climate and the CERN CLOUD Experiment

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    For more than two centuries, scientists have been puzzled by observations of solar-climate variability yet the lack of any established physical mechanism. Some recent observations, although disputed, suggest that clouds may be influenced by cosmic rays, which are modulated by the solar wind. The CLOUD experiment aims to settle the question of whether or not cosmic rays have a climatically-significant effect on clouds by carrying out a series of carefully-controlled measurements in a large cloud chamber exposed to a beam from the CERN PS. This talk will present the scientific motivation for CLOUD and the first results, which have recently been published in Nature (Kirkby et al. (2011). Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation. Nature 476, 429-433).

  7. Cloud CCN feedback

    International Nuclear Information System (INIS)

    Hudson, J.G.

    1992-01-01

    Cloud microphysics affects cloud albedo precipitation efficiency and the extent of cloud feedback in response to global warming. Compared to other cloud parameters, microphysics is unique in its large range of variability and the fact that much of the variability is anthropogenic. Probably the most important determinant of cloud microphysics is the spectra of cloud condensation nuclei (CCN) which display considerable variability and have a large anthropogenic component. When analyzed in combination three field observation projects display the interrelationship between CCN and cloud microphysics. CCN were measured with the Desert Research Institute (DRI) instantaneous CCN spectrometer. Cloud microphysical measurements were obtained with the National Center for Atmospheric Research Lockheed Electra. Since CCN and cloud microphysics each affect the other a positive feedback mechanism can result

  8. Proton beam monitor chamber calibration

    International Nuclear Information System (INIS)

    Gomà, C; Meer, D; Safai, S; Lorentini, S

    2014-01-01

    The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences—of the order of 3%—were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth—i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers—rather than cylindrical chambers—for the reference dosimetry of pseudo-monoenergetic proton beams. (paper)

  9. A small flat fission chamber

    International Nuclear Information System (INIS)

    Li Yijun; Wang Dalun; Chen Suhe

    1999-01-01

    With fission materials of depleted uranium, natural uranium, enriched uranium, 239 Pu, and 237 Np, the authors have designed and made a series of small flat fission chamber. The authors narrated the construction of the fission chamber and its technological process of manufacture, and furthermore, the authors have measured and discussed the follow correct factor, self-absorption, boundary effect, threshold loss factor, bottom scatter and or so

  10. Advances on fission chamber modelling

    International Nuclear Information System (INIS)

    Filliatre, Philippe; Jammes, Christian; Geslot, Benoit; Veenhof, Rob

    2013-06-01

    In-vessel, online neutron flux measurements are routinely performed in mock-up and material testing reactors by fission chambers. Those measurements have a wide range of applications, including characterization of experimental conditions, reactor monitoring and safety. Depending on the application, detectors may experience a wide range of constraints, of several magnitudes, in term of neutron flux, gamma-ray flux, temperature. Hence, designing a specific fission chamber and measuring chain for a given application is a demanding task. It can be achieved by a combination of experimental feedback and simulating tools, the latter being based on a comprehensive understanding of the underlying physics. A computation route that simulates fission chambers, named CHESTER, is presented. The retrieved quantities of interest are the neutron-induced charge spectrum, the electronic and ionic pulses, the mean current and variance, the power spectrum. It relies on the GARFIELD suite, originally developed for drift chambers, and makes use of the MAGBOLTZ code to assess the drift parameters of electrons within the filling gas, and the SRIM code to evaluate the stopping range of fission products. The effect of the gamma flux is also estimated. Computations made with several fission chambers exemplify the possibilities of the route. A good qualitative agreement is obtained when comparing the results with the experimental data available to date. In a near future, a comprehensive experimental programme will be undertaken to qualify the route using the known neutron sources, mock-up reactors and wide choice of fission chambers, with a stress on the predictiveness of the Campbelling mode. Depending on the results, a refinement of the modelling and an effort on the accuracy of input data are also to be considered. CHESTER will then make it possible to predict the overall sensitivity of a chamber, and to optimize the design for a given application. Another benefit will be to increase the

  11. BEBC Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    A view of the dismantling of the magnet of BEBC, the 3.7 m European Bubble Chamber : iron magnetic shielding ; lower and upper parts of the vacuum enclosure of the magnet; turbo-molecular vacuum pumps for the "fish-eye" windows; the two superconducting coils; a handling platform; the two cryostats suspended from the bar of the travelling crane which has a 170 ton carrying capacity. The chamber proper, not dismantled, is inside the shielding.

  12. The OPAL vertex drift chamber

    International Nuclear Information System (INIS)

    Carter, J.R.; Elcombe, P.A.; Hill, J.C.; Roach, C.M.; Armitage, J.C.; Carnegie, R.K.; Estabrooks, P.; Hemingway, R.; Karlen, D.; McPherson, A.; Pinfold, J.; Roney, J.M.; Routenburg, P.; Waterhouse, J.; Hargrove, C.K.; Klem, D.; Oakham, F.G.; Carter, A.A.; Jones, R.W.L.; Lasota, M.M.B.; Lloyd, S.L.; Pritchard, T.W.; Wyatt, T.R.

    1990-01-01

    A high precision vertex drift chamber has been installed in the OPAL experiment at LEP. The design of the chamber and the associated readout electronics is described. The performance of the system has been studied using cosmic ray muons and the results of these studies are presented. A space resolution of 50 μm in the drift direction is obtained using the OPAL central detector gas mixture at 4 bar. (orig.)

  13. Hybrid cloud for dummies

    CERN Document Server

    Hurwitz, Judith; Halper, Fern; Kirsch, Dan

    2012-01-01

    Understand the cloud and implement a cloud strategy for your business Cloud computing enables companies to save money by leasing storage space and accessing technology services through the Internet instead of buying and maintaining equipment and support services. Because it has its own unique set of challenges, cloud computing requires careful explanation. This easy-to-follow guide shows IT managers and support staff just what cloud computing is, how to deliver and manage cloud computing services, how to choose a service provider, and how to go about implementation. It also covers security and

  14. Secure cloud computing

    CERN Document Server

    Jajodia, Sushil; Samarati, Pierangela; Singhal, Anoop; Swarup, Vipin; Wang, Cliff

    2014-01-01

    This book presents a range of cloud computing security challenges and promising solution paths. The first two chapters focus on practical considerations of cloud computing. In Chapter 1, Chandramouli, Iorga, and Chokani describe the evolution of cloud computing and the current state of practice, followed by the challenges of cryptographic key management in the cloud. In Chapter 2, Chen and Sion present a dollar cost model of cloud computing and explore the economic viability of cloud computing with and without security mechanisms involving cryptographic mechanisms. The next two chapters addres

  15. Clouds of Venus

    Energy Technology Data Exchange (ETDEWEB)

    Knollenberg, R G [Particle Measuring Systems, Inc., 1855 South 57th Court, Boulder, Colorado 80301, U.S.A.; Hansen, J [National Aeronautics and Space Administration, New York (USA). Goddard Inst. for Space Studies; Ragent, B [National Aeronautics and Space Administration, Moffett Field, Calif. (USA). Ames Research Center; Martonchik, J [Jet Propulsion Lab., Pasadena, Calif. (USA); Tomasko, M [Arizona Univ., Tucson (USA)

    1977-05-01

    The current state of knowledge of the Venusian clouds is reviewed. The visible clouds of Venus are shown to be quite similar to low level terrestrial hazes of strong anthropogenic influence. Possible nucleation and particle growth mechanisms are presented. The Pioneer Venus experiments that emphasize cloud measurements are described and their expected findings are discussed in detail. The results of these experiments should define the cloud particle composition, microphysics, thermal and radiative heat budget, rough dynamical features and horizontal and vertical variations in these and other parameters. This information should be sufficient to initialize cloud models which can be used to explain the cloud formation, decay, and particle life cycle.

  16. PEP quark search proportional chambers

    Energy Technology Data Exchange (ETDEWEB)

    Parker, S I; Harris, F; Karliner, I; Yount, D [Hawaii Univ., Honolulu (USA); Ely, R; Hamilton, R; Pun, T [California Univ., Berkeley (USA). Lawrence Berkeley Lab.; Guryn, W; Miller, D; Fries, R [Northwestern Univ., Evanston, IL (USA)

    1981-04-01

    Proportional chambers are used in the PEP Free Quark Search to identify and remove possible background sources such as particles traversing the edges of counters, to permit geometric corrections to the dE/dx and TOF information from the scintillator and Cerenkov counters, and to look for possible high cross section quarks. The present beam pipe has a thickness of 0.007 interaction lengths (lambdasub(i)) and is followed in both arms each with 45/sup 0/ <= theta <= 135/sup 0/, ..delta..phi=90/sup 0/ by 5 proportional chambers, each 0.0008 lambdasub(i) thick with 32 channels of pulse height readout, and by 3 thin scintillator planes, each 0.003 lambdasub(i) thick. Following this thin front end, each arm of the detector has 8 layers of scintillator (one with scintillating light pipes) interspersed with 4 proportional chambers and a layer of lucite Cerenkov counters. Both the calculated ion statistics and measurements using He-CH/sub 4/ gas in a test chamber indicate that the chamber efficiencies should be >98% for q=1/3. The Landau spread measured in the test was equal to that observed for normal q=1 traversals. One scintillator plane and thin chamber in each arm will have an extra set of ADC's with a wide gate bracketing the normal one so timing errors and tails of earlier pulses should not produce fake quarks.

  17. Radiative properties of clouds

    International Nuclear Information System (INIS)

    Twomey, S.

    1993-01-01

    The climatic effects of condensation nuclei in the formation of cloud droplets and the subsequent role of the cloud droplets as contributors to the planetary short-wave albedo is emphasized. Microphysical properties of clouds, which can be greatly modified by the degree of mixing with cloud-free air from outside, are discussed. The effect of clouds on visible radiation is assessed through multiple scattering of the radiation. Cloudwater or ice absorbs more with increasing wavelength in the near-infrared region, with water vapor providing the stronger absorption over narrower wavelength bands. Cloud thermal infrared absorption can be solely related to liquid water content at least for shallow clouds and clouds in the early development state. Three-dimensional general circulation models have been used to study the climatic effect of clouds. It was found for such studies (which did not consider variations in cloud albedo) that the cooling effects due to the increase in planetary short-wave albedo from clouds were offset by heating effects due to thermal infrared absorption by the cloud. Two permanent direct effects of increased pollution are discussed in this chapter: (a) an increase of absorption in the visible and near infrared because of increased amounts of elemental carbon, which gives rise to a warming effect climatically, and (b) an increased optical thickness of clouds due to increasing cloud droplet number concentration caused by increasing cloud condensation nuclei number concentration, which gives rise to a cooling effect climatically. An increase in cloud albedo from 0.7 to 0.87 produces an appreciable climatic perturbation of cooling up to 2.5 K at the ground, using a hemispheric general circulation model. Effects of pollution on cloud thermal infrared absorption are negligible

  18. Moving towards Cloud Security

    Directory of Open Access Journals (Sweden)

    Edit Szilvia Rubóczki

    2015-01-01

    Full Text Available Cloud computing hosts and delivers many different services via Internet. There are a lot of reasons why people opt for using cloud resources. Cloud development is increasing fast while a lot of related services drop behind, for example the mass awareness of cloud security. However the new generation upload videos and pictures without reason to a cloud storage, but only few know about data privacy, data management and the proprietary of stored data in the cloud. In an enterprise environment the users have to know the rule of cloud usage, however they have little knowledge about traditional IT security. It is important to measure the level of their knowledge, and evolve the training system to develop the security awareness. The article proves the importance of suggesting new metrics and algorithms for measuring security awareness of corporate users and employees to include the requirements of emerging cloud security.

  19. Cloud Computing for radiologists.

    Science.gov (United States)

    Kharat, Amit T; Safvi, Amjad; Thind, Ss; Singh, Amarjit

    2012-07-01

    Cloud computing is a concept wherein a computer grid is created using the Internet with the sole purpose of utilizing shared resources such as computer software, hardware, on a pay-per-use model. Using Cloud computing, radiology users can efficiently manage multimodality imaging units by using the latest software and hardware without paying huge upfront costs. Cloud computing systems usually work on public, private, hybrid, or community models. Using the various components of a Cloud, such as applications, client, infrastructure, storage, services, and processing power, Cloud computing can help imaging units rapidly scale and descale operations and avoid huge spending on maintenance of costly applications and storage. Cloud computing allows flexibility in imaging. It sets free radiology from the confines of a hospital and creates a virtual mobile office. The downsides to Cloud computing involve security and privacy issues which need to be addressed to ensure the success of Cloud computing in the future.

  20. Cloud Computing for radiologists

    International Nuclear Information System (INIS)

    Kharat, Amit T; Safvi, Amjad; Thind, SS; Singh, Amarjit

    2012-01-01

    Cloud computing is a concept wherein a computer grid is created using the Internet with the sole purpose of utilizing shared resources such as computer software, hardware, on a pay-per-use model. Using Cloud computing, radiology users can efficiently manage multimodality imaging units by using the latest software and hardware without paying huge upfront costs. Cloud computing systems usually work on public, private, hybrid, or community models. Using the various components of a Cloud, such as applications, client, infrastructure, storage, services, and processing power, Cloud computing can help imaging units rapidly scale and descale operations and avoid huge spending on maintenance of costly applications and storage. Cloud computing allows flexibility in imaging. It sets free radiology from the confines of a hospital and creates a virtual mobile office. The downsides to Cloud computing involve security and privacy issues which need to be addressed to ensure the success of Cloud computing in the future

  1. Cloud computing for radiologists

    Directory of Open Access Journals (Sweden)

    Amit T Kharat

    2012-01-01

    Full Text Available Cloud computing is a concept wherein a computer grid is created using the Internet with the sole purpose of utilizing shared resources such as computer software, hardware, on a pay-per-use model. Using Cloud computing, radiology users can efficiently manage multimodality imaging units by using the latest software and hardware without paying huge upfront costs. Cloud computing systems usually work on public, private, hybrid, or community models. Using the various components of a Cloud, such as applications, client, infrastructure, storage, services, and processing power, Cloud computing can help imaging units rapidly scale and descale operations and avoid huge spending on maintenance of costly applications and storage. Cloud computing allows flexibility in imaging. It sets free radiology from the confines of a hospital and creates a virtual mobile office. The downsides to Cloud computing involve security and privacy issues which need to be addressed to ensure the success of Cloud computing in the future.

  2. Directional muon jet chamber for a muon collider (Groovy Chamber)

    International Nuclear Information System (INIS)

    Atac, M.

    1996-10-01

    A directional jet drift chamber with PAD readout is proposed here which can select vertex originated muons within a given time window and eliminate those muons which primarily originate upstream, using only a PAD readout. Drift time provides the Z-coordinate, and the center of gravity of charge distribution provides the r-ψ coordinates. Directionality at the trigger level is obtained by the timing measurement from the PAD hits within a given time window. Because of the long drift time between the bunch crossings, a muon collider enables one to choose a drift distance in the drift chamber as long as 50 cm. This is an important factor in reducing cost of drift chambers which have to cover relatively large areas

  3. Marine cloud brightening

    OpenAIRE

    Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John

    2012-01-01

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could—subject to satisfactory resolution of technical and scientific problems identi...

  4. Cloud computing strategies

    CERN Document Server

    Chorafas, Dimitris N

    2011-01-01

    A guide to managing cloud projects, Cloud Computing Strategies provides the understanding required to evaluate the technology and determine how it can be best applied to improve business and enhance your overall corporate strategy. Based on extensive research, it examines the opportunities and challenges that loom in the cloud. It explains exactly what cloud computing is, what it has to offer, and calls attention to the important issues management needs to consider before passing the point of no return regarding financial commitments.

  5. Towards Indonesian Cloud Campus

    OpenAIRE

    Thamrin, Taqwan; Lukman, Iing; Wahyuningsih, Dina Ika

    2013-01-01

    Nowadays, Cloud Computing is most discussed term in business and academic environment.Cloud campus has many benefits such as accessing the file storages, e-mails, databases,educational resources, research applications and tools anywhere for faculty, administrators,staff, students and other users in university, on demand. Furthermore, cloud campus reduces universities’ IT complexity and cost.This paper discuss the implementation of Indonesian cloud campus and various opportunies and benefits...

  6. Cloud Infrastructure Security

    OpenAIRE

    Velev , Dimiter; Zlateva , Plamena

    2010-01-01

    Part 4: Security for Clouds; International audience; Cloud computing can help companies accomplish more by eliminating the physical bonds between an IT infrastructure and its users. Users can purchase services from a cloud environment that could allow them to save money and focus on their core business. At the same time certain concerns have emerged as potential barriers to rapid adoption of cloud services such as security, privacy and reliability. Usually the information security professiona...

  7. Cloud services in organization

    OpenAIRE

    FUXA, Jan

    2013-01-01

    The work deals with the definition of the word cloud computing, cloud computing models, types, advantages, disadvantages, and comparing SaaS solutions such as: Google Apps and Office 365 in the area of electronic communications. The work deals with the use of cloud computing in the corporate practice, both good and bad practice. The following section describes the methodology for choosing the appropriate cloud service organization. Another part deals with analyzing the possibilities of SaaS i...

  8. Orchestrating Your Cloud Orchestra

    OpenAIRE

    Hindle, Abram

    2015-01-01

    Cloud computing potentially ushers in a new era of computer music performance with exceptionally large computer music instruments consisting of 10s to 100s of virtual machines which we propose to call a `cloud-orchestra'. Cloud computing allows for the rapid provisioning of resources, but to deploy such a complicated and interconnected network of software synthesizers in the cloud requires a lot of manual work, system administration knowledge, and developer/operator skills. This is a barrier ...

  9. Cloud security mechanisms

    OpenAIRE

    2014-01-01

    Cloud computing has brought great benefits in cost and flexibility for provisioning services. The greatest challenge of cloud computing remains however the question of security. The current standard tools in access control mechanisms and cryptography can only partly solve the security challenges of cloud infrastructures. In the recent years of research in security and cryptography, novel mechanisms, protocols and algorithms have emerged that offer new ways to create secure services atop cloud...

  10. Cloud computing for radiologists

    OpenAIRE

    Amit T Kharat; Amjad Safvi; S S Thind; Amarjit Singh

    2012-01-01

    Cloud computing is a concept wherein a computer grid is created using the Internet with the sole purpose of utilizing shared resources such as computer software, hardware, on a pay-per-use model. Using Cloud computing, radiology users can efficiently manage multimodality imaging units by using the latest software and hardware without paying huge upfront costs. Cloud computing systems usually work on public, private, hybrid, or community models. Using the various components of a Cloud, such as...

  11. Cloud Robotics Model

    OpenAIRE

    Mester, Gyula

    2015-01-01

    Cloud Robotics was born from the merger of service robotics and cloud technologies. It allows robots to benefit from the powerful computational, storage, and communications resources of modern data centres. Cloud robotics allows robots to take advantage of the rapid increase in data transfer rates to offload tasks without hard real time requirements. Cloud Robotics has rapidly gained momentum with initiatives by companies such as Google, Willow Garage and Gostai as well as more than a dozen a...

  12. Genomics With Cloud Computing

    OpenAIRE

    Sukhamrit Kaur; Sandeep Kaur

    2015-01-01

    Abstract Genomics is study of genome which provides large amount of data for which large storage and computation power is needed. These issues are solved by cloud computing that provides various cloud platforms for genomics. These platforms provides many services to user like easy access to data easy sharing and transfer providing storage in hundreds of terabytes more computational power. Some cloud platforms are Google genomics DNAnexus and Globus genomics. Various features of cloud computin...

  13. Chargeback for cloud services.

    NARCIS (Netherlands)

    Baars, T.; Khadka, R.; Stefanov, H.; Jansen, S.; Batenburg, R.; Heusden, E. van

    2014-01-01

    With pay-per-use pricing models, elastic scaling of resources, and the use of shared virtualized infrastructures, cloud computing offers more efficient use of capital and agility. To leverage the advantages of cloud computing, organizations have to introduce cloud-specific chargeback practices.

  14. Cloud Computing Explained

    Science.gov (United States)

    Metz, Rosalyn

    2010-01-01

    While many talk about the cloud, few actually understand it. Three organizations' definitions come to the forefront when defining the cloud: Gartner, Forrester, and the National Institutes of Standards and Technology (NIST). Although both Gartner and Forrester provide definitions of cloud computing, the NIST definition is concise and uses…

  15. Greening the Cloud

    NARCIS (Netherlands)

    van den Hoed, Robert; Hoekstra, Eric; Procaccianti, G.; Lago, P.; Grosso, Paola; Taal, Arie; Grosskop, Kay; van Bergen, Esther

    The cloud has become an essential part of our daily lives. We use it to store our documents (Dropbox), to stream our music and lms (Spotify and Net ix) and without giving it any thought, we use it to work on documents in the cloud (Google Docs). The cloud forms a massive storage and processing

  16. Security in the cloud.

    Science.gov (United States)

    Degaspari, John

    2011-08-01

    As more provider organizations look to the cloud computing model, they face a host of security-related questions. What are the appropriate applications for the cloud, what is the best cloud model, and what do they need to know to choose the best vendor? Hospital CIOs and security experts weigh in.

  17. Plasma chemistry in wire chambers

    International Nuclear Information System (INIS)

    Wise, J.

    1990-05-01

    The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an 55 Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed

  18. Electron Cloud Parameterization Studies in the LHC

    CERN Document Server

    Dominguez, O; Baglin, V; Bregliozzi, G; Jimenez, J M; Metral, E; Rumolo, G; Schulte, D; Zimmermann, F

    2011-01-01

    During LHC beam commissioning with 150, 75 and 50-ns bunch spacing, important electron-cloud effects, like pressure rise, cryogenic heat load, beam instabilities or emittance growth, were observed. The main strategy to combat the LHC electron cloud, defined about ten years ago, relies on the surface conditioning arising from the chamber-surface bombardment with cloud electrons. In a standard model, the conditioning state of the beam-pipe surface is characterized by three parameters: 1. most importantly, the secondary emission yield δmax; 2. the incident electron energy at which the yield is maximum, ε_max; and 3. the probability of elastic reflection of low-energy primary electrons hitting the chamber wall, R. Since at the LHC no in-situ secondary-yield measurements are available, we compare the relative local pressure-rise measurements taken for different beam configurations against simulations in which surface parameters are scanned. This benchmarking of measurements and simulations is used to infer the s...

  19. Electron cloud buildup studies for the LHC

    CERN Document Server

    AUTHOR|(CDS)2160803; Boine-Frankenheim, Oliver

    Electron clouds can develop in accelerators operating with positively charged particles. The con- sequences of e-cloud related effects are very important for the operation of the Large Hadron Collider (LHC) at CERN, and for the design of future accelerators including the LHC luminosity upgrade (HL-LHC). High electron densities are generated by an interaction between the beam and the confining chamber. Primary electrons, that can be generated through various mecha- nisms, are accelerated by the beam and impinge on the chamber walls, thereby extracting more electrons from the material. Furthermore they also deposit their kinetic energy in the process, which has to be compensated by the cooling system. Especially in cryogenic environments, as it is the case for a large part of the LHC, high heat loads can pose a serious problem. In order to improve the understanding of the electron cloud, simulation studies are performed with the code PyECLOUD, developed at CERN. The work of the first half of the project is desc...

  20. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

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

  1. An experimental propane bubble chamber

    International Nuclear Information System (INIS)

    Rogozinski, A.

    1957-01-01

    Describes a propane bubble chamber 10 cm in diameter and 5 cm deep. The body of the chamber is in stainless steel, and it has two windows of polished hardened glass. The compression and decompression of the propane are performed either through a piston in direct contact with the liquid, or by the action on the liquid, through a triple-mylar-Perbunan membrane, of a compressed gas. The general and also optimum working conditions of the chamber are described, and a few results are given concerning, in particular, the tests of the breakage-resistance of the windows and the measurements of the thermal expansion of the compressibility isotherm for the propane employed. (author) [fr

  2. Equipment for handling ionization chamber

    International Nuclear Information System (INIS)

    Altmann, J.

    1988-01-01

    The device consists of an ionization channel with an ionization chamber, of a support ring, axial and radial bearings, a sleeve, a screw gear and an electric motor. The ionization chamber is freely placed on the bottom of the ionization channel. The bottom part of the channel deviates from the vertical axis. The support ring propped against the axial bearing in the sleeve is firmly fixed to the top part of the ionization channel. The sleeve is fixed to the reactor lid. Its bottom part is provided with a recess for the radial bearing which is propped against a screw wheel firmly connected to the ionization channel. In measuring neutron flux, the screw wheel is rotated by the motor, thus rotating the whole ionization channel such that the ionization chamber is displaced into the reactor core.(J.B.). 1 fig

  3. General purpose nuclear irradiation chamber

    International Nuclear Information System (INIS)

    Nurul Fadzlin Hasbullah; Nuurul Iffah Che Omar; Nahrul Khair Alang Md Rashid; Jaafar Abdullah

    2013-01-01

    Nuclear technology has found a great need for use in medicine, industry, and research. Smoke detectors in our homes, medical treatments and new varieties of plants by irradiating its seeds are just a few examples of the benefits of nuclear technology. Portable neutron source such as Californium-252, available at Industrial Technology Division (BTI/ PAT), Malaysian Nuclear Agency, has a 2.645 year half-life. However, 252 Cf is known to emit gamma radiation from the source. Thus, this chamber aims to provide a proper gamma shielding for samples to distinguish the use of mixed neutron with gamma-rays or pure neutron radiation. The chamber is compatible to be used with other portable neutron sources such as 241 Am-Be as well as the reactor TRIGA PUSPATI for higher neutron dose. This chamber was designed through a collaborative effort of Kulliyyah Engineering, IIUM with the Industrial Technology Division (BTI) team, Malaysian Nuclear Agency. (Author)

  4. Holography in small bubble chambers

    International Nuclear Information System (INIS)

    Lecoq, P.

    1984-01-01

    This chapter reports on an experiment to determine the total charm cross section at different incident momenta using the small, heavy liquid bubble chamber HOBC. Holography in liquid hydrogen is also tested using the holographic lexan bubble chamber HOLEBC with the aim of preparing a future holographic experiment in hydrogen. The high intensity tests show that more than 100 incident tracks per hologram do not cause a dramatic effect on the picture quality. Hydrogen is more favorable than freon as the bubble growth is much slower in hydrogen. An advantage of holography is to have the maximum resolution in the full volume of the bubble chamber, which allows a gain in sensitivity by a factor of 10 compared to classical optics as 100 tracks per hologram look reasonable. Holograms are not more difficult to analyze than classical optics high-resolution pictures. The results show that holography is a very powerful technique which can be used in very high resolution particle physics experiments

  5. CLOUD STORAGE SERVICES

    OpenAIRE

    Yan, Cheng

    2017-01-01

    Cloud computing is a hot topic in recent research and applications. Because it is widely used in various fields. Up to now, Google, Microsoft, IBM, Amazon and other famous co partnership have proposed their cloud computing application. Look upon cloud computing as one of the most important strategy in the future. Cloud storage is the lower layer of cloud computing system which supports the service of the other layers above it. At the same time, it is an effective way to store and manage heavy...

  6. Cloud Computing Quality

    Directory of Open Access Journals (Sweden)

    Anamaria Şiclovan

    2013-02-01

    Full Text Available Cloud computing was and it will be a new way of providing Internet services and computers. This calculation approach is based on many existing services, such as the Internet, grid computing, Web services. Cloud computing as a system aims to provide on demand services more acceptable as price and infrastructure. It is exactly the transition from computer to a service offered to the consumers as a product delivered online. This paper is meant to describe the quality of cloud computing services, analyzing the advantages and characteristics offered by it. It is a theoretical paper.Keywords: Cloud computing, QoS, quality of cloud computing

  7. Benchmarking Cloud Storage Systems

    OpenAIRE

    Wang, Xing

    2014-01-01

    With the rise of cloud computing, many cloud storage systems like Dropbox, Google Drive and Mega have been built to provide decentralized and reliable file storage. It is thus of prime importance to know their features, performance, and the best way to make use of them. In this context, we introduce BenchCloud, a tool designed as part of this thesis to conveniently and efficiently benchmark any cloud storage system. First, we provide a study of six commonly-used cloud storage systems to ident...

  8. The Magellanic clouds

    International Nuclear Information System (INIS)

    1989-01-01

    As the two galaxies nearest to our own, the Magellanic Clouds hold a special place in studies of the extragalactic distance scale, of stellar evolution and the structure of galaxies. In recent years, results from the South African Astronomical Observatory (SAAO) and elsewhere have shown that it is possible to begin understanding the three dimensional structure of the Clouds. Studies of Magellanic Cloud Cepheids have continued, both to investigate the three-dimensional structure of the Clouds and to learn more about Cepheids and their use as extragalactic distance indicators. Other research undertaken at SAAO includes studies on Nova LMC 1988 no 2 and red variables in the Magellanic Clouds

  9. Cloud Computing Bible

    CERN Document Server

    Sosinsky, Barrie

    2010-01-01

    The complete reference guide to the hot technology of cloud computingIts potential for lowering IT costs makes cloud computing a major force for both IT vendors and users; it is expected to gain momentum rapidly with the launch of Office Web Apps later this year. Because cloud computing involves various technologies, protocols, platforms, and infrastructure elements, this comprehensive reference is just what you need if you'll be using or implementing cloud computing.Cloud computing offers significant cost savings by eliminating upfront expenses for hardware and software; its growing popularit

  10. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  11. Laboratory Course on Drift Chambers

    International Nuclear Information System (INIS)

    Garcia-Ferreira, Ix-B.; Garcia-Herrera, J.; Villasenor, L.

    2006-01-01

    Drift chambers play an important role in particle physics experiments as tracking detectors. We started this laboratory course with a brief review of the theoretical background and then moved on to the the experimental setup which consisted of a single-sided, single-cell drift chamber. We also used a plastic scintillator paddle, standard P-10 gas mixture (90% Ar, 10% CH4) and a collimated 90Sr source. During the laboratory session the students performend measurements of the following quantities: a) drift velocities and their variations as function of the drift field; b) gas gains and c) diffusion of electrons as they drifted in the gas

  12. The knife-edge chamber

    International Nuclear Information System (INIS)

    Barasch, E.F.; Bowcock, T.J.V.; Drew, M.M.; Elliott, S.M.; Lee, B.; McIntyre, P.M.; Pang, Y.; Popovic, M.; Smith, D.D.

    1990-01-01

    In this paper the design for a new technology for particle track detectors is described. Using standard IC fabrication techniques, a pattern of microscopic knife edges and field-shaping electrodes can be fabricated on a silicon substrate. The knife-edge chamber uniquely offers attractive performance for the track chambers required for SSC detectors, for which no present technology is yet satisfactory. Its features include: excellent radiation hardness (10 Mrad), excellent spatial resolution (∼20 μm), short drift time (20 ns), and large pulse height (1 mV)

  13. Ionization chambers for LET determination

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki

    2010-01-01

    resolution and high sensitivity are necessary. For exact dosimetry which is done using ionization chambers (ICs), the recombination taking place in the IC has to be known. Up to now, recombination is corrected phenomenologically and more practical approaches are currently used. Nevertheless, Jaff´e's theory...... of columnar recombination was designed to model the detector efficiency of an ionization chamber. Here, we have shown that despite the approximations and simplification made, the theory is correct for the LETs typically found in clinical radiotherapy employing particles from protons to carbon ions...

  14. The Mark III vertex chamber

    International Nuclear Information System (INIS)

    Adler, J.; Bolton, T.; Bunnell, K.

    1987-07-01

    The design and construction of the new Mark III vertex chamber is described. Initial tests with cosmic rays prove the ability of track reconstruction and yield triplet resolutions below 50 μm at 3 atm using argon/ethane (50:50). Also performed are studies using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. Spatial resolution of 35mm was obtained using dimethyl ether (DME) at 1 atm and 30 μm using argon/ethane (50/50 mixture) at 4 atm. Preliminary studies indicate the DME to adversely affect such materials as aluminized Mylar and Delrin

  15. CLOUD COMPUTING SECURITY

    Directory of Open Access Journals (Sweden)

    Ştefan IOVAN

    2016-05-01

    Full Text Available Cloud computing reprentes the software applications offered as a service online, but also the software and hardware components from the data center.In the case of wide offerd services for any type of client, we are dealing with a public cloud. In the other case, in wich a cloud is exclusively available for an organization and is not available to the open public, this is consider a private cloud [1]. There is also a third type, called hibrid in which case an user or an organization might use both services available in the public and private cloud. One of the main challenges of cloud computing are to build the trust and ofer information privacy in every aspect of service offerd by cloud computingle. The variety of existing standards, just like the lack of clarity in sustenability certificationis not a real help in building trust. Also appear some questions marks regarding the efficiency of traditionsecurity means that are applied in the cloud domain. Beside the economic and technology advantages offered by cloud, also are some advantages in security area if the information is migrated to cloud. Shared resources available in cloud includes the survey, use of the "best practices" and technology for advance security level, above all the solutions offered by the majority of medium and small businesses, big companies and even some guvermental organizations [2].

  16. Testing an hydrogen streamer chamber

    CERN Multimedia

    1975-01-01

    A 2x10 cm gap streamer chamber, 35x55 cm2 in surface, was built and tested at CERN. Good tracks of cosmic rays were obtained up to atmospheric pressure, see F. Rohrbach et al, CERN-LAL (Orsay) Collaboration, Nucl. Instr. Methods 141 (1977) 229. Michel Cathenoz stand on the center.

  17. Bubble chamber: colour enhanced tracks

    CERN Multimedia

    1998-01-01

    This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

  18. Searchable Encryption in Cloud Storage

    OpenAIRE

    Ren-Junn Hwang; Chung-Chien Lu; Jain-Shing Wu

    2014-01-01

    Cloud outsource storage is one of important services in cloud computing. Cloud users upload data to cloud servers to reduce the cost of managing data and maintaining hardware and software. To ensure data confidentiality, users can encrypt their files before uploading them to a cloud system. However, retrieving the target file from the encrypted files exactly is difficult for cloud server. This study proposes a protocol for performing multikeyword searches for encrypted cloud data by applying ...

  19. Hydrostatic Hyperbaric Chamber Ventilation System

    Science.gov (United States)

    Sarguisingh, Miriam J.

    2012-01-01

    The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy (HBOT) available in the developing world for the treatment of a variety of medical conditions. Specifically, HBOT is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. HBOT is simply too expensive and too dangerous to implement in the developing world using standard equipment. The HHC technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system to provide controlled pressurization and adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware

  20. Enterprise Cloud Adoption - Cloud Maturity Assessment Model

    OpenAIRE

    Conway, Gerry; Doherty, Eileen; Carcary, Marian; Crowley, Catherine

    2017-01-01

    The introduction and use of cloud computing by an organization has the promise of significant benefits that include reduced costs, improved services, and a pay-per-use model. Organizations that successfully harness these benefits will potentially have a distinct competitive edge, due to their increased agility and flexibility to rapidly respond to an ever changing and complex business environment. However, as cloud technology is a relatively new ph...

  1. Measurements of the electron cloud in the APS storage ring

    International Nuclear Information System (INIS)

    Harkey, K. C.

    1999-01-01

    Synchrotron radiation interacting with the vacuum chamber walls in a storage ring produce photoelectrons that can be accelerated by the beam, acquiring sufficient energy to produce secondary electrons in collisions with the walls. If the secondary-electron yield (SEY) coefficient of the wall material is greater than one, as is the case with the aluminum chambers in the Advanced Photon Source (APS) storage ring, a runaway condition can develop. As the electron cloud builds up along a train of stored positron or electron bunches, the possibility exists that a transverse perturbation of the head bunch will be communicated to trailing bunches due to interaction with the cloud. In order to characterize the electron cloud, a special vacuum chamber was built and inserted into the ring. The chamber contains 10 rudimentary electron-energy analyzers, as well as three targets coated with different materials. Measurements show that the intensity and electron energy distribution are highly dependent on the temporal spacing between adjacent bunches and the amount of current contained in each bunch. Furthermore, measurements using the different targets are consistent with what would be expected based on the SEY of the coatings. Data for both positron and electron beams are presented

  2. Star clouds of Magellan

    International Nuclear Information System (INIS)

    Tucker, W.

    1981-01-01

    The Magellanic Clouds are two irregular galaxies belonging to the local group which the Milky Way belongs to. By studying the Clouds, astronomers hope to gain insight into the origin and composition of the Milky Way. The overall structure and dynamics of the Clouds are clearest when studied in radio region of the spectrum. One benefit of directly observing stellar luminosities in the Clouds has been the discovery of the period-luminosity relation. Also, the Clouds are a splendid laboratory for studying stellar evolution. It is believed that both Clouds may be in the very early stage in the development of a regular, symmetric galaxy. This raises a paradox because some of the stars in the star clusters of the Clouds are as old as the oldest stars in our galaxy. An explanation for this is given. The low velocity of the Clouds with respect to the center of the Milky Way shows they must be bound to it by gravity. Theories are given on how the Magellanic Clouds became associated with the galaxy. According to current ideas the Clouds orbits will decay and they will spiral into the Galaxy

  3. Cloud Computing Governance Lifecycle

    Directory of Open Access Journals (Sweden)

    Soňa Karkošková

    2016-06-01

    Full Text Available Externally provisioned cloud services enable flexible and on-demand sourcing of IT resources. Cloud computing introduces new challenges such as need of business process redefinition, establishment of specialized governance and management, organizational structures and relationships with external providers and managing new types of risk arising from dependency on external providers. There is a general consensus that cloud computing in addition to challenges brings many benefits but it is unclear how to achieve them. Cloud computing governance helps to create business value through obtain benefits from use of cloud computing services while optimizing investment and risk. Challenge, which organizations are facing in relation to governing of cloud services, is how to design and implement cloud computing governance to gain expected benefits. This paper aims to provide guidance on implementation activities of proposed Cloud computing governance lifecycle from cloud consumer perspective. Proposed model is based on SOA Governance Framework and consists of lifecycle for implementation and continuous improvement of cloud computing governance model.

  4. THE CALIFORNIA MOLECULAR CLOUD

    International Nuclear Information System (INIS)

    Lada, Charles J.; Lombardi, Marco; Alves, Joao F.

    2009-01-01

    We present an analysis of wide-field infrared extinction maps of a region in Perseus just north of the Taurus-Auriga dark cloud complex. From this analysis we have identified a massive, nearby, but previously unrecognized, giant molecular cloud (GMC). Both a uniform foreground star density and measurements of the cloud's velocity field from CO observations indicate that this cloud is likely a coherent structure at a single distance. From comparison of foreground star counts with Galactic models, we derive a distance of 450 ± 23 pc to the cloud. At this distance the cloud extends over roughly 80 pc and has a mass of ∼ 10 5 M sun , rivaling the Orion (A) molecular cloud as the largest and most massive GMC in the solar neighborhood. Although surprisingly similar in mass and size to the more famous Orion molecular cloud (OMC) the newly recognized cloud displays significantly less star formation activity with more than an order of magnitude fewer young stellar objects than found in the OMC, suggesting that both the level of star formation and perhaps the star formation rate in this cloud are an order of magnitude or more lower than in the OMC. Analysis of extinction maps of both clouds shows that the new cloud contains only 10% the amount of high extinction (A K > 1.0 mag) material as is found in the OMC. This, in turn, suggests that the level of star formation activity and perhaps the star formation rate in these two clouds may be directly proportional to the total amount of high extinction material and presumably high density gas within them and that there might be a density threshold for star formation on the order of n(H 2 ) ∼ a few x 10 4 cm -3 .

  5. CLEARING OF ELECTRON CLOUD IN SNS

    International Nuclear Information System (INIS)

    WANG, L.; LEE, Y.Y.; RAPRIA, D.

    2004-01-01

    In this paper we describe a mechanism using the clearing electrodes to remove the electron cloud in the Spallation Neutron Source (SNS) accumulator ring, where strong multipacting could happen at median clearing fields. A similar phenomenon was reported in an experimental study at Los Alamos laboratory's Proton Synchrotron Ring (PSR). We also investigated the effectiveness of the solenoid's clearing mechanism in the SNS, which differs from the short bunch case, such as in B-factories. The titanium nitride (TiN) coating of the chamber walls was applied to reduce the secondary electron yield (SEY)

  6. Results from the CERN pilot CLOUD experiment

    DEFF Research Database (Denmark)

    Duplissy, J.; Enghoff, Martin Andreas Bødker; Aplin, K.L.

    2010-01-01

    the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest...... become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber...

  7. Establishment of a radon test chamber

    International Nuclear Information System (INIS)

    Chen Chingjiang; Liu Chichang; Lin Yuming

    1993-01-01

    A walk-in type radon test chamber of 23 m 3 has been built for testing and calibration of radon measurement instruments. The environmental conditions of the test chamber can be varied within a wide range of values. The design objectives specification, monitoring instruments and testing results of this chamber are discussed. This test chamber is available for domestic radon researchers and its accuracy can be traced to the international standard. A routine intercomparison study will be held annually by using this chamber. Other tests like radon progeny and thoron standard may also be performed in this chamber. (1 fig.)

  8. Pencil-shaped radiation detection ionization chamber

    International Nuclear Information System (INIS)

    Suzuki, A.

    1979-01-01

    A radiation detection ionization chamber is described. It consists of an elongated cylindrical pencil-shaped tubing forming an outer wall of the chamber and a center electrode disposed along the major axis of the tubing. The length of the chamber is substantially greater than the diameter. A cable connecting portion at one end of the chamber is provided for connecting the chamber to a triaxial cable. An end support portion is connected at the other end of the chamber for supporting and tensioning the center electrode. 17 claims

  9. Single Particle Laser Mass Spectrometry Applied to Differential Ice Nucleation Experiments at the AIDA Chamber

    International Nuclear Information System (INIS)

    Gallavardin, S. J.; Froyd, Karl D.; Lohmann, U.; Moehler, Ottmar; Murphy, Daniel M.; Cziczo, Dan

    2008-01-01

    Experiments conducted at the Aerosol Interactions and Dynamics in the Atmosphere (AIDA) chamber located in Karlsruhe, Germany permit investigation of particle properties that affect the nucleation of ice at temperature and water vapor conditions relevant to cloud microphysics and climate issues. Ice clouds were generated by heterogeneous nucleation of Arizona test dust (ATD), illite, and hematite and homogeneous nucleation of sulfuric acid. Ice crystals formed in the chamber were inertially separated from unactivated, or 'interstitial' aerosol particles with a pumped counterflow virtual impactor (PCVI), then evaporated. The ice residue (i.e., the aerosol which initiated ice nucleation plus any material which was scavenged from the gas- and/or particle-phase), was chemically characterized at the single particle level using a laser ionization mass spectrometer. In this manner the species that first nucleated ice could be identified out of a mixed aerosol population in the chamber. Bare mineral dust particles were more effective ice nuclei (IN) than similar particles with a coating. Metallic particles from contamination in the chamber initiated ice nucleation before other species but there were few enough that they did not compromise the experiments. Nitrate, sulfate, and organics were often detected on particles and ice residue, evidently from scavenging of trace gas-phase species in the chamber. Hematite was a more effective ice nucleus than illite. Ice residue was frequently larger than unactivated test aerosol due to the formation of aggregates due to scavenging, condensation of contaminant gases, and the predominance of larger aerosol in nucleation

  10. Expansion of magnetic clouds

    International Nuclear Information System (INIS)

    Suess, S.T.

    1987-01-01

    Magnetic clouds are a carefully defined subclass of all interplanetary signatures of coronal mass ejections whose geometry is thought to be that of a cylinder embedded in a plane. It has been found that the total magnetic pressure inside the clouds is higher than the ion pressure outside, and that the clouds are expanding at 1 AU at about half the local Alfven speed. The geometry of the clouds is such that even though the magnetic pressure inside is larger than the total pressure outside, expansion will not occur because the pressure is balanced by magnetic tension - the pinch effect. The evidence for expansion of clouds at 1 AU is nevertheless quite strong so another reason for its existence must be found. It is demonstrated that the observations can be reproduced by taking into account the effects of geometrical distortion of the low plasma beta clouds as they move away from the Sun

  11. Encyclopedia of cloud computing

    CERN Document Server

    Bojanova, Irena

    2016-01-01

    The Encyclopedia of Cloud Computing provides IT professionals, educators, researchers and students with a compendium of cloud computing knowledge. Authored by a spectrum of subject matter experts in industry and academia, this unique publication, in a single volume, covers a wide range of cloud computing topics, including technological trends and developments, research opportunities, best practices, standards, and cloud adoption. Providing multiple perspectives, it also addresses questions that stakeholders might have in the context of development, operation, management, and use of clouds. Furthermore, it examines cloud computing's impact now and in the future. The encyclopedia presents 56 chapters logically organized into 10 sections. Each chapter covers a major topic/area with cross-references to other chapters and contains tables, illustrations, side-bars as appropriate. Furthermore, each chapter presents its summary at the beginning and backend material, references and additional resources for further i...

  12. Considerations for Cloud Security Operations

    OpenAIRE

    Cusick, James

    2016-01-01

    Information Security in Cloud Computing environments is explored. Cloud Computing is presented, security needs are discussed, and mitigation approaches are listed. Topics covered include Information Security, Cloud Computing, Private Cloud, Public Cloud, SaaS, PaaS, IaaS, ISO 27001, OWASP, Secure SDLC.

  13. Evaluating statistical cloud schemes

    OpenAIRE

    Grützun, Verena; Quaas, Johannes; Morcrette , Cyril J.; Ament, Felix

    2015-01-01

    Statistical cloud schemes with prognostic probability distribution functions have become more important in atmospheric modeling, especially since they are in principle scale adaptive and capture cloud physics in more detail. While in theory the schemes have a great potential, their accuracy is still questionable. High-resolution three-dimensional observational data of water vapor and cloud water, which could be used for testing them, are missing. We explore the potential of ground-based re...

  14. Cloud Computing Governance Lifecycle

    OpenAIRE

    Soňa Karkošková; George Feuerlicht

    2016-01-01

    Externally provisioned cloud services enable flexible and on-demand sourcing of IT resources. Cloud computing introduces new challenges such as need of business process redefinition, establishment of specialized governance and management, organizational structures and relationships with external providers and managing new types of risk arising from dependency on external providers. There is a general consensus that cloud computing in addition to challenges brings many benefits but it is uncle...

  15. Security in cloud computing

    OpenAIRE

    Moreno Martín, Oriol

    2016-01-01

    Security in Cloud Computing is becoming a challenge for next generation Data Centers. This project will focus on investigating new security strategies for Cloud Computing systems. Cloud Computingisarecent paradigmto deliver services over Internet. Businesses grow drastically because of it. Researchers focus their work on it. The rapid access to exible and low cost IT resources on an on-demand fashion, allows the users to avoid planning ahead for provisioning, and enterprises to save money ...

  16. Accelerated search of gamma-quantum families in a X-ray emulsion chamber

    International Nuclear Information System (INIS)

    Takibaev, Zh.S.; Bajgubekov, A.S.; Sadykov, T.Kh.

    1977-01-01

    The criteria are derived allowing to considerably accelerate the process of detecting the pure gamma-quantum families. The suitable criterion is the apparent size of the distribution of black spots due to electromagnetic cascades inside a circle of specific radius. The results of assaying 27 gamma-families with energies above 3 TeV generated in a target above the chamber are presented. The method of search for the target families suggested in this paper allows to cut four-fold the roentgen-emulsion cloud chamber treatment time

  17. CLOUD TECHNOLOGY IN EDUCATION

    Directory of Open Access Journals (Sweden)

    Alexander N. Dukkardt

    2014-01-01

    Full Text Available This article is devoted to the review of main features of cloud computing that can be used in education. Particular attention is paid to those learning and supportive tasks, that can be greatly improved in the case of the using of cloud services. Several ways to implement this approach are proposed, based on widely accepted models of providing cloud services. Nevertheless, the authors have not ignored currently existing problems of cloud technologies , identifying the most dangerous risks and their impact on the core business processes of the university. 

  18. Cloud Computing: An Overview

    Science.gov (United States)

    Qian, Ling; Luo, Zhiguo; Du, Yujian; Guo, Leitao

    In order to support the maximum number of user and elastic service with the minimum resource, the Internet service provider invented the cloud computing. within a few years, emerging cloud computing has became the hottest technology. From the publication of core papers by Google since 2003 to the commercialization of Amazon EC2 in 2006, and to the service offering of AT&T Synaptic Hosting, the cloud computing has been evolved from internal IT system to public service, from cost-saving tools to revenue generator, and from ISP to telecom. This paper introduces the concept, history, pros and cons of cloud computing as well as the value chain and standardization effort.

  19. Genomics With Cloud Computing

    Directory of Open Access Journals (Sweden)

    Sukhamrit Kaur

    2015-04-01

    Full Text Available Abstract Genomics is study of genome which provides large amount of data for which large storage and computation power is needed. These issues are solved by cloud computing that provides various cloud platforms for genomics. These platforms provides many services to user like easy access to data easy sharing and transfer providing storage in hundreds of terabytes more computational power. Some cloud platforms are Google genomics DNAnexus and Globus genomics. Various features of cloud computing to genomics are like easy access and sharing of data security of data less cost to pay for resources but still there are some demerits like large time needed to transfer data less network bandwidth.

  20. Development of multiwire proportional chambers

    CERN Multimedia

    Charpak, G

    1969-01-01

    It has happened quite often in the history of science that theoreticians, confronted with some major difficulty, have successfully gone back thirty years to look at ideas that had then been thrown overboard. But it is rare that experimentalists go back thirty years to look again at equipment which had become out-dated. This is what Charpak and his colleagues did to emerge with the 'multiwire proportional chamber' which has several new features making it a very useful addition to the armoury of particle detectors. In the 1930s, ion-chambers, Geiger- Muller counters and proportional counters, were vital pieces of equipment in nuclear physics research. Other types of detectors have since largely replaced them but now the proportional counter, in new array, is making a comeback.

  1. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The structure of LEP, with long bending magnets and little access to the vacuum chamber between them, required distributed pumping. This is an early prototype for the LEP vacuum chamber, made from extruded aluminium. The main opening is for the beam. The small channel to the right is for cooling water, to carry away the heat deposited by the synchroton radiation from the beam. The 4 slots in the channel to the left house the strip-shaped ion-getter pumps (see 7810255). The ion-getter pumps depended on the magnetic field of the bending magnets, too low at injection energy for the pumps to function well. Also, a different design was required outside the bending magnets. This design was therefore abandoned, in favour of a thermal getter pump (see 8301153 and 8305170).

  2. Single wire drift chamber design

    International Nuclear Information System (INIS)

    Krider, J.

    1987-01-01

    This report summarizes the design and prototype tests of single wire drift chambers to be used in Fermilab test beam lines. The goal is to build simple, reliable detectors which require a minimum of electronics. Spatial resolution should match the 300 μm rms resolution of the 1 mm proportional chambers that they will replace. The detectors will be used in beams with particle rates up to 20 KHz. Single track efficiency should be at least 99%. The first application will be in the MT beamline, which has been designed for calibration of CDF detectors. A set of four x-y modules will be used to track and measure the momentum of beam particles

  3. MPS II drift chamber system

    International Nuclear Information System (INIS)

    Platner, E.D.

    1982-01-01

    The MPS II detectors are narrow drift space chambers designed for high position resolution in a magnetic field and in a very high particle flux environment. Central to this implementation was the development of 3 multi-channel custom IC's and one multi-channel hybrid. The system is deadtimeless and requires no corrections on an anode-to-anode basis. Operational experience and relevance to ISABELLE detectors is discussed

  4. GBO RF Anechoic Chamber & Antenna Test Range

    Data.gov (United States)

    Federal Laboratory Consortium — A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna...

  5. The KEK 1 m hydrogen bubble chamber

    International Nuclear Information System (INIS)

    Doi, Yoshikuni; Araoka, Osamu; Hayashi, Kohei; Hayashi, Yoshio; Hirabayashi, Hiromi.

    1978-03-01

    A medium size hydrogen bubble chamber has been constructed at the National Laboratory for High Energy Physics, KEK. The bubble chamber has been designed to be operated with a maximum rate of three times per half a second in every two second repetition time of the accelerator, by utilizing a hydraulic expansion system. The bubble chamber has a one meter diameter and a visible volume of about 280 l. A three-view stereo camera system is used for taking photographic pictures of the chamber. A 2 MW bubble chamber magnet is constructed. The main part of the bubble chamber vessel is supported by the magnet yoke. The magnet gives a maximum field of 18.4 kG at the centre of the fiducial volume of the chamber. The overall system of the KEK 1 m hydrogen bubble chamber facility is described in some detail. Some operational characteristics of the facility are also reported. (auth.)

  6. Review of Cloud Computing and existing Frameworks for Cloud adoption

    OpenAIRE

    Chang, Victor; Walters, Robert John; Wills, Gary

    2014-01-01

    This paper presents a selected review for Cloud Computing and explains the benefits and risks of adopting Cloud Computing in a business environment. Although all the risks identified may be associated with two major Cloud adoption challenges, a framework is required to support organisations as they begin to use Cloud and minimise risks of Cloud adoption. Eleven Cloud Computing frameworks are investigated and a comparison of their strengths and limitations is made; the result of the comparison...

  7. +Cloud: An Agent-Based Cloud Computing Platform

    OpenAIRE

    González, Roberto; Hernández de la Iglesia, Daniel; de la Prieta Pintado, Fernando; Gil González, Ana Belén

    2017-01-01

    Cloud computing is revolutionizing the services provided through the Internet, and is continually adapting itself in order to maintain the quality of its services. This study presents the platform +Cloud, which proposes a cloud environment for storing information and files by following the cloud paradigm. This study also presents Warehouse 3.0, a cloud-based application that has been developed to validate the services provided by +Cloud.

  8. Dorsal skinfold chamber models in mice

    Directory of Open Access Journals (Sweden)

    Schreiter, Jeannine

    2017-07-01

    Full Text Available Background/purpose: The use of dorsal skinfold chamber models has substantially improved the understanding of micro-vascularisation in pathophysiology over the last eight decades. It allows pathophysiological studies of vascularisation over a continuous period of time. The dorsal skinfold chamber is an attractive technique for monitoring the vascularisation of autologous or allogenic transplants, wound healing, tumorigenesis and compatibility of biomaterial implants. To further reduce the animals’ discomfort while carrying the dorsal skinfold chamber, we developed a smaller chamber (the Leipzig Dorsal Skinfold Chamber and summarized the commercial available chamber models. In addition we compared our model to the common chamber. Methods: The Leipzig Dorsal Skinfold Chamber was applied to female mice with a mean weight of 22 g. Angiogenesis within the dorsal skinfold chamber was evaluated after injection of fluorescein isothiocyanate dextran with an Axio Scope microscope. The mean vessel density within the dorsal skinfold chamber was assessed over a period of 21 days at five different time points. The gained data were compared to previous results using a bigger and heavier dorsal skinfold model in mice. A PubMed and a patent search were performed and all papers related to “dorsal skinfold chamber” from 1 of January 2006 to 31 of December 2015 were evaluated regarding the dorsal skinfold chamber models and their technical improvements. The main models are described and compared to our titanium Leipzig Dorsal Skinfold Chamber model.Results: The Leipzig Dorsal Skinfold Chamber fulfils all requirements of continuous models known from previous chamber models while reducing irritation to the mice. Five different chamber models have been identified showing substantial regional diversity. The newly elaborated titanium dorsal skinfold chamber may replace the pre-existing titanium chamber model used in Germany so far, as it is smaller and lighter

  9. Growing and analyzing biofilms in flow chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber-grown biofilms are addressed....

  10. Lost in Cloud

    Science.gov (United States)

    Maluf, David A.; Shetye, Sandeep D.; Chilukuri, Sri; Sturken, Ian

    2012-01-01

    Cloud computing can reduce cost significantly because businesses can share computing resources. In recent years Small and Medium Businesses (SMB) have used Cloud effectively for cost saving and for sharing IT expenses. With the success of SMBs, many perceive that the larger enterprises ought to move into Cloud environment as well. Government agency s stove-piped environments are being considered as candidates for potential use of Cloud either as an enterprise entity or pockets of small communities. Cloud Computing is the delivery of computing as a service rather than as a product, whereby shared resources, software, and information are provided to computers and other devices as a utility over a network. Underneath the offered services, there exists a modern infrastructure cost of which is often spread across its services or its investors. As NASA is considered as an Enterprise class organization, like other enterprises, a shift has been occurring in perceiving its IT services as candidates for Cloud services. This paper discusses market trends in cloud computing from an enterprise angle and then addresses the topic of Cloud Computing for NASA in two possible forms. First, in the form of a public Cloud to support it as an enterprise, as well as to share it with the commercial and public at large. Second, as a private Cloud wherein the infrastructure is operated solely for NASA, whether managed internally or by a third-party and hosted internally or externally. The paper addresses the strengths and weaknesses of both paradigms of public and private Clouds, in both internally and externally operated settings. The content of the paper is from a NASA perspective but is applicable to any large enterprise with thousands of employees and contractors.

  11. Impedances in lossy elliptical vacuum chambers

    International Nuclear Information System (INIS)

    Piwinski, A.

    1994-04-01

    The wake fields of a bunched beam caused by the resistivity of the chamber walls are investigated for a vacuum chamber with elliptical cross section. The longitudinal and transverse impedances are calculated for arbitrary energies and for an arbitrary position of the beam in the chamber. (orig.)

  12. Wire chamber degradation at the Argonne ZGS

    International Nuclear Information System (INIS)

    Haberichter, W.; Spinka, H.

    1986-01-01

    Experience with multiwire proportional chambers at high rates at the Argonne Zero Gradient Synchrotron is described. A buildup of silicon on the sense wires was observed where the beam passed through the chamber. Analysis of the chamber gas indicated that the density of silicon was probably less than 10 ppM

  13. Sensitivity of gaseous xenon ionisation chambers (1961)

    International Nuclear Information System (INIS)

    Schuhl, C.

    1960-01-01

    It seems advantageous to fill an ionization chamber with xenon gas when this chamber is used for measuring a low intensity and high energy electron or positron beam, or monitoring a gamma beam. In the study of 5 to 50 MeV electrons, xenon allows for the ionization chamber yield, an improvement of a factor 4,5. (author) [fr

  14. The Carrier Gas Pressure Effect in a Laminar Flow Diffusion Chamber, Homogeneous Nucleation of n-Butanol in Helium

    Czech Academy of Sciences Publication Activity Database

    Hyvärinen, A-P.; Brus, David; Ždímal, Vladimír; Smolík, Jiří; Kulmala, M.; Viisanen, V.; Lihavainen, H.

    2006-01-01

    Roč. 124, č. 22 (2006), Art. No. 224304 ISSN 0021-9606 R&D Projects: GA AV ČR(CZ) IAA2076203 Institutional research plan: CEZ:AV0Z40720504 Keywords : supersaturated vapor * cloud chamber * background gas es Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2006

  15. Proportional chambers and multiwire drift chambers at high rates

    International Nuclear Information System (INIS)

    Walenta, A.H.

    1977-01-01

    The high event and particle rates expected for ISABELLE intersecting storage rings raise the question whether PWC's and drift chambers, now widely in use in experiments, still can operate under such conditions. Various effects depend on the number of avalanches produced per length of wire N and the size of the avalanche Q, i.e., on the number of positive ions created in an avalanche. Therefore the important parameter for the following discussion is the product QN. The minimum Q is determined by the type and noise level of preamplifiers used. Examples are given for a typical low noise amplifier as well as for a typical integrated ''cheap'' amplifier. The rate/wire length N depends on the chamber arrangement, wire spacing, etc. In multiwire drift chambers, a single wire shows space-charge effects reducing the pulse height by 1% at a rate of N = 7 x 10 3 mm -1 sec -1 . At a rate of N approximately equal to 10 5 mm -1 sec -1 an efficiency loss of the order of 1% was noticed. The aging effect due to deposits on the anode wire can be reduced using low noise amplifiers and low gas gain to such an extent that a lifetime of about half a year at ISABELLE can be expected. The use of conventional cheap preamplifiers will result in a typical lifetime of about 30 days. Improvements are probable. The time resolution of Δt/sub r/ = 4 nsec fwhm seems adequate for event rates of 10 7 sec -1 . The memory time Δt/sub m/ greater than or equal to 100 nsec may cause serious problems for pattern recognition depending on layout and readout. The use of induced signals on cathode pads, thus reading out shorter parts of the wire, can solve the problem

  16. Research on cloud computing solutions

    OpenAIRE

    Liudvikas Kaklauskas; Vaida Zdanytė

    2015-01-01

    Cloud computing can be defined as a new style of computing in which dynamically scala-ble and often virtualized resources are provided as a services over the Internet. Advantages of the cloud computing technology include cost savings, high availability, and easy scalability. Voas and Zhang adapted six phases of computing paradigms, from dummy termi-nals/mainframes, to PCs, networking computing, to grid and cloud computing. There are four types of cloud computing: public cloud, private cloud, ...

  17. VMware vCloud security

    CERN Document Server

    Sarkar, Prasenjit

    2013-01-01

    VMware vCloud Security provides the reader with in depth knowledge and practical exercises sufficient to implement a secured private cloud using VMware vCloud Director and vCloud Networking and Security.This book is primarily for technical professionals with system administration and security administration skills with significant VMware vCloud experience who want to learn about advanced concepts of vCloud security and compliance.

  18. Security Architecture of Cloud Computing

    OpenAIRE

    V.KRISHNA REDDY; Dr. L.S.S.REDDY

    2011-01-01

    The Cloud Computing offers service over internet with dynamically scalable resources. Cloud Computing services provides benefits to the users in terms of cost and ease of use. Cloud Computing services need to address the security during the transmission of sensitive data and critical applications to shared and public cloud environments. The cloud environments are scaling large for data processing and storage needs. Cloud computing environment have various advantages as well as disadvantages o...

  19. Security in hybrid cloud computing

    OpenAIRE

    Koudelka, Ondřej

    2016-01-01

    This bachelor thesis deals with the area of hybrid cloud computing, specifically with its security. The major aim of the thesis is to analyze and compare the chosen hybrid cloud providers. For the minor aim this thesis compares the security challenges of hybrid cloud as opponent to other deployment models. In order to accomplish said aims, this thesis defines the terms cloud computing and hybrid cloud computing in its theoretical part. Furthermore the security challenges for cloud computing a...

  20. Cloud security in vogelvlucht

    NARCIS (Netherlands)

    Pieters, Wolter

    2011-01-01

    Cloud computing is dé hype in IT op het moment, en hoewel veel aspecten niet nieuw zijn, leidt het concept wel tot de noodzaak voor nieuwe vormen van beveiliging. Het idee van cloud computing biedt echter ook juist kansen om hierover na te denken: wat is de rol van informatiebeveiliging in een

  1. CLOUD SERVICES IN EDUCATION

    Directory of Open Access Journals (Sweden)

    Z.S. Seydametova

    2011-05-01

    Full Text Available We present the on-line services based on cloud computing, provided by Google to educational institutions. We describe the own experience of the implementing the Google Apps Education Edition in the educational process. We analyzed and compared the other universities experience of using cloud technologies.

  2. Cloud MicroAtlas

    Indian Academy of Sciences (India)

    We begin by outlining the life cycle of a tall cloud, and thenbriefly discuss cloud systems. We choose one aspect of thislife cycle, namely, the rapid growth of water droplets in ice freeclouds, to then discuss in greater detail. Taking a singlevortex to be a building block of turbulence, we demonstrateone mechanism by which ...

  3. Greening the cloud

    NARCIS (Netherlands)

    van den Hoed, Robert; Hoekstra, Eric; Procaccianti, Giuseppe; Lago, Patricia; Grosso, Paolo; Taal, Arie; Grosskop, Kay; van Bergen, Esther

    The cloud has become an essential part of our daily lives. We use it to store our documents (Dropbox), to stream our music and films (Spotify and Netflix) and without giving it any thought, we use it to work on documents in the cloud (Google Docs).

  4. Learning in the Clouds?

    Science.gov (United States)

    Butin, Dan W.

    2013-01-01

    Engaged learning--the type that happens outside textbooks and beyond the four walls of the classroom--moves beyond right and wrong answers to grappling with the uncertainties and contradictions of a complex world. iPhones back up to the "cloud." GoogleDocs is all about "cloud computing." Facebook is as ubiquitous as the sky.…

  5. Kernel structures for Clouds

    Science.gov (United States)

    Spafford, Eugene H.; Mckendry, Martin S.

    1986-01-01

    An overview of the internal structure of the Clouds kernel was presented. An indication of how these structures will interact in the prototype Clouds implementation is given. Many specific details have yet to be determined and await experimentation with an actual working system.

  6. Comparing contact and immersion freezing from continuous flow diffusion chambers

    Directory of Open Access Journals (Sweden)

    B. Nagare

    2016-07-01

    Full Text Available Ice nucleating particles (INPs in the atmosphere are responsible for glaciating cloud droplets between 237 and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. To date, direct comparisons of contact and immersion freezing with the same INP, for similar residence times and concentrations, are lacking. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data were obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH using 80 µm diameter droplets, which can interact with INPs for residence times of 2 and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter Arizona Test Dust (ATD and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm−3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm−3 for AgI. For concentrations  <  5000 cm−3, the droplets collect only one particle on average during their time in the chamber. For ATD and kaolinite particles, contact freezing efficiencies at 2 s residence time were smaller than at 4 s, which is in disagreement with a collisional contact freezing process but in accordance with immersion freezing or adhesion freezing. With “adhesion freezing”, we refer to a contact nucleation

  7. Characterization of Mixed-Phase Clouds in the Laboratory

    Science.gov (United States)

    Foster, T. C.; Hallett, J.

    2005-12-01

    A technique was developed in which a mixed-phase cloud of controllable ice and water content is created. First a freezer filled with a water droplet cloud becomes supercooled. Then, in an isolated small volume of the freezer, an adjustable adiabatic expansion locally nucleates ice. Finally the two regions of the cloud are vigorously stirred together producing a mixed-phase cloud throughout the chamber. At this point the water droplets evaporate and the crystals grow at a slow measurable rate, until a fully glaciated cloud results. Experiments were carried out at temperatures near -20 C in a standard top-opening chest freezer. A cloud of supercooled water droplets several micrometers in diameter was produced by a commercial ultrasonic nebulizer. Ice was nucleated using the discharge of an empty compressed air pistol pumped to different initial pressures. In that process high-pressure room temperature air in the pistol expands adiabatically, cooling the air enough to nucleate water droplets which then freeze homogeneously if sufficiently cold. The freezer was partitioned with thick movable walls of foam material to isolate the ice cloud in a small volume of the freezer before mixing occurs. Clouds of supercooled water droplets or of ice particles are readily produced and examined in collimated white light beams. They look similar visually in some cases although normally large crystals with flat reflecting surfaces clearly differ due to the flashes of reflected light. When the pistol is discharged into the supercooled water cloud, it displays a distinct hazy bluish "plume." But discharge into the ice particle cloud leaves no such plume: that discharge only mixes the particles present. This discharge is a test of glaciation in our initially mixed freezer cloud. A visible plume indicates that supercooled water remains in the cloud and no plume indicates the cloud is entirely ice at a high concentration. Our first unsuccessful experiments were done with the freezer

  8. Dimethylamine and ammonia measurements with ion chromatography during the CLOUD4 campaign

    CERN Document Server

    Praplan, A P; Dommen, J; Baltensperger, U

    2012-01-01

    The CLOUD project investigates the influence of galactic cosmic rays on the nucleation of new particles in an environmental chamber at CERN. Dimethylamine (DMA) was injected intentionally into the CLOUD chamber to reach atmospherically relevant levels away from sources (up to 100 pptv) in order to study its effect on nucleation with sulphuric acid and water at 278 K. Quantification of DMA and also background ammonia (NH 3 ) was performed with ion chromatography (IC). The IC method used together with the sampling line developed for CLOUD in order to measure NH 3 and DMA at low pptv levels is described; the overall sampling efficiency of the method is discussed; and, finally, mixing ratios of NH 3 and DMA measured during CLOUD4 are reported.

  9. Cloud computing basics

    CERN Document Server

    Srinivasan, S

    2014-01-01

    Cloud Computing Basics covers the main aspects of this fast moving technology so that both practitioners and students will be able to understand cloud computing. The author highlights the key aspects of this technology that a potential user might want to investigate before deciding to adopt this service. This book explains how cloud services can be used to augment existing services such as storage, backup and recovery. Addressing the details on how cloud security works and what the users must be prepared for when they move their data to the cloud. Also this book discusses how businesses could prepare for compliance with the laws as well as industry standards such as the Payment Card Industry.

  10. Solar variability and clouds

    CERN Document Server

    Kirkby, Jasper

    2000-01-01

    Satellite observations have revealed a surprising imprint of the 11- year solar cycle on global low cloud cover. The cloud data suggest a correlation with the intensity of Galactic cosmic rays. If this apparent connection between cosmic rays and clouds is real, variations of the cosmic ray flux caused by long-term changes in the solar wind could have a significant influence on the global energy radiation budget and the climate. However a direct link between cosmic rays and clouds has not been unambiguously established and, moreover, the microphysical mechanism is poorly understood. New experiments are being planned to find out whether cosmic rays can affect cloud formation, and if so how. (37 refs).

  11. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London...

  12. Proceedings of workshop on streamer chamber

    International Nuclear Information System (INIS)

    Itoh, Hidihiko; Takahashi, Kaoru; Hirose, Tachishige; Masaike, Akira

    1978-08-01

    For high accuracy observation of multiple-body reactions, a vertex detector of high efficiency is essential. A bubble chamber, though excellent for tracks detection, is problematic in statistics accuracy. The vertex detector with a wire chamber, while better in this respect, difficult in multiple-particle detection etc. The workshop has had several meetings on a streamer chamber as a detector combining features of both bubble chamber and counter, with emphasis on tracks observation in avalanche mode and recordings not using films. Contents are on streamer chamber gas, analytical photography, data processing, simulation program, etc. (Mori, K.)

  13. Stratocumulus Cloud Top Radiative Cooling and Cloud Base Updraft Speeds

    Science.gov (United States)

    Kazil, J.; Feingold, G.; Balsells, J.; Klinger, C.

    2017-12-01

    Cloud top radiative cooling is a primary driver of turbulence in the stratocumulus-topped marine boundary. A functional relationship between cloud top cooling and cloud base updraft speeds may therefore exist. A correlation of cloud top radiative cooling and cloud base updraft speeds has been recently identified empirically, providing a basis for satellite retrieval of cloud base updraft speeds. Such retrievals may enable analysis of aerosol-cloud interactions using satellite observations: Updraft speeds at cloud base co-determine supersaturation and therefore the activation of cloud condensation nuclei, which in turn co-determine cloud properties and precipitation formation. We use large eddy simulation and an off-line radiative transfer model to explore the relationship between cloud-top radiative cooling and cloud base updraft speeds in a marine stratocumulus cloud over the course of the diurnal cycle. We find that during daytime, at low cloud water path (CWP correlated, in agreement with the reported empirical relationship. During the night, in the absence of short-wave heating, CWP builds up (CWP > 50 g m-2) and long-wave emissions from cloud top saturate, while cloud base heating increases. In combination, cloud top cooling and cloud base updrafts become weakly anti-correlated. A functional relationship between cloud top cooling and cloud base updraft speed can hence be expected for stratocumulus clouds with a sufficiently low CWP and sub-saturated long-wave emissions, in particular during daytime. At higher CWPs, in particular at night, the relationship breaks down due to saturation of long-wave emissions from cloud top.

  14. Properties of the electron cloud in a high-energy positron and electron storage ring

    International Nuclear Information System (INIS)

    Harkay, K.C.; Rosenberg, R.A.

    2003-01-01

    Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in a positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.

  15. Formation of Massive Molecular Cloud Cores by Cloud-cloud Collision

    OpenAIRE

    Inoue, Tsuyoshi; Fukui, Yasuo

    2013-01-01

    Recent observations of molecular clouds around rich massive star clusters including NGC3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by the cloud-cloud collision. We find that the massive mol...

  16. Chamber propagation physics for heavy ion fusion

    International Nuclear Information System (INIS)

    Callahan, D.A.

    1995-01-01

    Chamber transport is an important area of study for heavy ion fusion. Final focus and chamber-transport are high leverage areas providing opportunities to significantly decrease the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime (approx-lt 0.003 torr), ballistic or nearly-ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime (approx-gt.1 torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber then transporting it at small radius (∼ 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity

  17. Chamber propagation physics for heavy ion fusion

    International Nuclear Information System (INIS)

    Callahan, D.A.

    1996-01-01

    Chamber transport is a key area of study for heavy ion fusion. Final focus and chamber transport are high leverage areas providing opportunities to decrease significantly the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime (below about 0.003 Torr), ballistic or nearly ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime (above about 0.1 Torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber and then transporting it at small radius (about 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity. (orig.)

  18. Loss of ions in cavity ionization chambers

    International Nuclear Information System (INIS)

    Takata, N.; Tran, N.T.; Kim, E.; Marsoem, P.; Kurosawa, T.; Koyama, Y.

    2005-01-01

    Ion losses due to initial recombination, volume recombination, and back diffusion were each determined by measurements and calculations for different size cylindrical ionization chambers and spherical ionization chambers. By measuring signal currents from these ionization chambers irradiated with 60 Co gamma rays, two groups of ion losses were obtained. (Group 1) Ion loss due to initial recombination and diffusion, which changes proportionally to the inverse of the voltage applied to the ionization chambers; (and group 2) ion loss due to volume recombination, which changes proportionally to the inverse of the square of the applied voltage. The diffusion loss was obtained separately by computing electric field distributions in the ionization chambers. It was found that diffusion loss is larger than initial recombination loss for the cylindrical ionization chambers and vise versa for the spherical ionization chambers

  19. TRU waste characterization chamber gloveboxes

    International Nuclear Information System (INIS)

    Duncan, D. S.

    1998-01-01

    Argonne National Laboratory-West (ANL-W) is participating in the Department of Energy's (DOE) National Transuranic Waste Program in support of the Waste Isolation Pilot Plant (WIPP). The Laboratory's support currently consists of intrusive characterization of a selected population of drums containing transuranic waste. This characterization is performed in a complex of alpha containment gloveboxes termed the Waste Characterization Gloveboxes. Made up of the Waste Characterization Chamber, Sample Preparation Glovebox, and the Equipment Repair Glovebox, they were designed as a small production characterization facility for support of the Idaho National Engineering and Environmental Laboratory (INEEL). This paper presents salient features of these gloveboxes

  20. Experimental work on drift chambers

    International Nuclear Information System (INIS)

    Alcaraz, J.; Duran, I.; Gonzalez, E.; Martinez-Laso, L.; Olmos, P.

    1989-01-01

    An experimental work made on drift chambers is described in two chapters. In the firt chapter we present the description of the experimental installation used, as well as some details on the data adquisition systems and the characteristics on three ways used for calibration proposes (cosmic muons, β radiation and test beam using SPS at CERN facilities). The second chapter describes the defferent prototypes studied. The experimental set up and the analysis are given. Some results are discussed. The magnetic field effect is also studied. (Author)

  1. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

    1979-05-01

    An engineering study was performed to determine the most effective method for decontamination of the Nova target chamber. Manual and remote decontamination methods currently being used were surveyed. In addition, a concept that may not require in-situ decontamination was investigated. Based on the presently available information concerning material and system compatibility and particle penetration, it is recommended that a system of removable aluminum shields be considered. It is also recommended that a series of tests be performed to more precisely determine the vacuum compatibility and penetrability of other materials discussed in this report

  2. Gnathostomiasis of the anterior chamber

    Directory of Open Access Journals (Sweden)

    Barua P

    2007-01-01

    Full Text Available Ocular involvement with Gnathostoma spinigerum occurs years after the initial infection that is acquired by ingestion of poorly cooked, pickled seafood or water contaminated with third stage larvae. Here we report a case of gnathostomiasis of the left eye of a 32-year-old lady hailing from Meghalaya, India. Her vision had deteriorated to hand movement. Slit lamp examination revealed a live, actively motile worm in the anterior chamber, which was extracted by supra temporal limbal incision and visual acuity was restored.

  3. Making and Breaking Clouds

    Science.gov (United States)

    Kohler, Susanna

    2017-10-01

    Molecular clouds which youre likely familiar with from stunning popular astronomy imagery lead complicated, tumultuous lives. A recent study has now found that these features must be rapidly built and destroyed.Star-Forming CollapseA Hubble view of a molecular cloud, roughly two light-years long, that has broken off of the Carina Nebula. [NASA/ESA, N. Smith (University of California, Berkeley)/The Hubble Heritage Team (STScI/AURA)]Molecular gas can be found throughout our galaxy in the form of eminently photogenic clouds (as featured throughout this post). Dense, cold molecular gas makes up more than 20% of the Milky Ways total gas mass, and gravitational instabilities within these clouds lead them to collapse under their own weight, resulting in the formation of our galaxys stars.How does this collapse occur? The simplest explanation is that the clouds simply collapse in free fall, with no source of support to counter their contraction. But if all the molecular gas we observe collapsed on free-fall timescales, star formation in our galaxy would churn a rate thats at least an order of magnitude higher than the observed 12 solar masses per year in the Milky Way.Destruction by FeedbackAstronomers have theorized that there may be some mechanism that supports these clouds against gravity, slowing their collapse. But both theoretical studies and observations of the clouds have ruled out most of these potential mechanisms, and mounting evidence supports the original interpretation that molecular clouds are simply gravitationally collapsing.A sub-mm image from ESOs APEX telescope of part of the Taurus molecular cloud, roughly ten light-years long, superimposed on a visible-light image of the region. [ESO/APEX (MPIfR/ESO/OSO)/A. Hacar et al./Digitized Sky Survey 2. Acknowledgment: Davide De Martin]If this is indeed the case, then one explanation for our low observed star formation rate could be that molecular clouds are rapidly destroyed by feedback from the very stars

  4. Cloud Computing: An Overview

    Directory of Open Access Journals (Sweden)

    Libor Sarga

    2012-10-01

    Full Text Available As cloud computing is gaining acclaim as a cost-effective alternative to acquiring processing resources for corporations, scientific applications and individuals, various challenges are rapidly coming to the fore. While academia struggles to procure a concise definition, corporations are more interested in competitive advantages it may generate and individuals view it as a way of speeding up data access times or a convenient backup solution. Properties of the cloud architecture largely preclude usage of existing practices while achieving end-users’ and companies’ compliance requires considering multiple infrastructural as well as commercial factors, such as sustainability in case of cloud-side interruptions, identity management and off-site corporate data handling policies. The article overviews recent attempts at formal definitions of cloud computing, summarizes and critically evaluates proposed delimitations, and specifies challenges associated with its further proliferation. Based on the conclusions, future directions in the field of cloud computing are also briefly hypothesized to include deeper focus on community clouds and bolstering innovative cloud-enabled platforms and devices such as tablets, smart phones, as well as entertainment applications.

  5. Cloud Computing Law

    CERN Document Server

    Millard, Christopher

    2013-01-01

    This book is about the legal implications of cloud computing. In essence, ‘the cloud’ is a way of delivering computing resources as a utility service via the internet. It is evolving very rapidly with substantial investments being made in infrastructure, platforms and applications, all delivered ‘as a service’. The demand for cloud resources is enormous, driven by such developments as the deployment on a vast scale of mobile apps and the rapid emergence of ‘Big Data’. Part I of this book explains what cloud computing is and how it works. Part II analyses contractual relationships between cloud service providers and their customers, as well as the complex roles of intermediaries. Drawing on primary research conducted by the Cloud Legal Project at Queen Mary University of London, cloud contracts are analysed in detail, including the appropriateness and enforceability of ‘take it or leave it’ terms of service, as well as the scope for negotiating cloud deals. Specific arrangements for public sect...

  6. Community Cloud Computing

    Science.gov (United States)

    Marinos, Alexandros; Briscoe, Gerard

    Cloud Computing is rising fast, with its data centres growing at an unprecedented rate. However, this has come with concerns over privacy, efficiency at the expense of resilience, and environmental sustainability, because of the dependence on Cloud vendors such as Google, Amazon and Microsoft. Our response is an alternative model for the Cloud conceptualisation, providing a paradigm for Clouds in the community, utilising networked personal computers for liberation from the centralised vendor model. Community Cloud Computing (C3) offers an alternative architecture, created by combing the Cloud with paradigms from Grid Computing, principles from Digital Ecosystems, and sustainability from Green Computing, while remaining true to the original vision of the Internet. It is more technically challenging than Cloud Computing, having to deal with distributed computing issues, including heterogeneous nodes, varying quality of service, and additional security constraints. However, these are not insurmountable challenges, and with the need to retain control over our digital lives and the potential environmental consequences, it is a challenge we must pursue.

  7. Physicist makes muon chamber sing

    CERN Multimedia

    2007-01-01

    This Monitored Drift Tube detector, consisting of argon-CO2-filled aluminium tubes with a wire down the centre of each, will track muons in ATLAS; Tiecke used a single tube from one of these detectors to create the pipes in his organ. Particle physicists can make good musicians; but did you know particle detectors can make good music? That's what NIKHEF physicist Henk Tiecke learned when he used pipes cut from the ATLAS Monitored Drift Tube detector (MDT) to build his own working Dutch-style barrel organ in the autumn of 2005. 'I like to work with my hands,' said Tiecke, who worked as a senior physicist at NIKHEF, Amsterdam, on ZEUS until his retirement last summer. Tiecke had already constructed his barrel organ when he visited some colleagues in the ATLAS muon chambers production area at Nikhef in 2005. He noticed that the aluminium tubes they were using to build the chambers were about three centimetres in diameter-just the right size for a pipe in a barrel organ. 'The sound is not as nice as from wooden...

  8. Multipactor for e-cloud diagnostics

    CERN Document Server

    Costa Pinto, P; Edwards, P; Holz, M; Taborelli, M

    2012-01-01

    Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed through a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic fields. Preliminary results show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power...

  9. Diffuse interstellar clouds

    International Nuclear Information System (INIS)

    Black, J.H.

    1987-01-01

    The author defines and discusses the nature of diffuse interstellar clouds. He discusses how they contribute to the general extinction of starlight. The atomic and molecular species that have been identified in the ultraviolet, visible, and near infrared regions of the spectrum of a diffuse cloud are presented. The author illustrates some of the practical considerations that affect absorption line observations of interstellar atoms and molecules. Various aspects of the theoretical description of diffuse clouds required for a full interpretation of the observations are discussed

  10. Cloud Computing Security

    OpenAIRE

    Ngongang, Guy

    2011-01-01

    This project aimed to show how possible it is to use a network intrusion detection system in the cloud. The security in the cloud is a concern nowadays and security professionals are still finding means to make cloud computing more secure. First of all the installation of the ESX4.0, vCenter Server and vCenter lab manager in server hardware was successful in building the platform. This allowed the creation and deployment of many virtual servers. Those servers have operating systems and a...

  11. Aerosols, clouds and radiation

    Energy Technology Data Exchange (ETDEWEB)

    Twomey, S [University of Arizona, Tucson, AZ (USA). Inst. of Atmospheric Physics

    1991-01-01

    Most of the so-called 'CO{sub 2} effect' is, in fact, an 'H{sub 2}O effect' brought into play by the climate modeler's assumption that planetary average temperature dictates water-vapor concentration (following Clapeyron-Clausius). That assumption ignores the removal process, which cloud physicists know to be influenced by the aerosol, since the latter primarily controls cloud droplet number and size. Droplet number and size are also influential for shortwave (solar) energy. The reflectance of many thin to moderately thick clouds changes when nuclei concentrations change and make shortwave albedo susceptible to aerosol influence.

  12. Trusted cloud computing

    CERN Document Server

    Krcmar, Helmut; Rumpe, Bernhard

    2014-01-01

    This book documents the scientific results of the projects related to the Trusted Cloud Program, covering fundamental aspects of trust, security, and quality of service for cloud-based services and applications. These results aim to allow trustworthy IT applications in the cloud by providing a reliable and secure technical and legal framework. In this domain, business models, legislative circumstances, technical possibilities, and realizable security are closely interwoven and thus are addressed jointly. The book is organized in four parts on "Security and Privacy", "Software Engineering and

  13. COMPARATIVE STUDY OF CLOUD COMPUTING AND MOBILE CLOUD COMPUTING

    OpenAIRE

    Nidhi Rajak*, Diwakar Shukla

    2018-01-01

    Present era is of Information and Communication Technology (ICT) and there are number of researches are going on Cloud Computing and Mobile Cloud Computing such security issues, data management, load balancing and so on. Cloud computing provides the services to the end user over Internet and the primary objectives of this computing are resource sharing and pooling among the end users. Mobile Cloud Computing is a combination of Cloud Computing and Mobile Computing. Here, data is stored in...

  14. Molecular clouds near supernova remnants

    International Nuclear Information System (INIS)

    Wootten, H.A.

    1978-01-01

    The physical properties of molecular clouds near supernova remnants were investigated. Various properties of the structure and kinematics of these clouds are used to establish their physical association with well-known remmnants. An infrared survey of the most massive clouds revealed embedded objects, probably stars whose formation was induced by the supernova blast wave. In order to understand the relationship between these and other molecular clouds, a control group of clouds was also observed. Excitation models for dense regions of all the clouds are constructed to evaluate molecular abundances in these regions. Those clouds that have embedded stars have lower molecular abundances than the clouds that do not. A cloud near the W28 supernova remnant also has low abundances. Molecular abundances are used to measure an important parameter, the electron density, which is not directly observable. In some clouds extensive deuterium fractionation is observed which confirms electron density measurements in those clouds. Where large deuterium fractionation is observed, the ionization rate in the cloud interior can also be measured. The electron density and ionization rate in the cloud near W28 are higher than in most clouds. The molecular abundances and electron densities are functions of the chemical and dynamical state of evolution of the cloud. Those clouds with lowest abundances are probably the youngest clouds. As low-abundance clouds, some clouds near supernova remnants may have been recently swept from the local interstellar material. Supernova remnants provide sites for star formation in ambient clouds by compressing them, and they sweep new clouds from more diffuse local matter

  15. Taxonomy of cloud computing services

    NARCIS (Netherlands)

    Hoefer, C.N.; Karagiannis, Georgios

    2010-01-01

    Cloud computing is a highly discussed topic, and many big players of the software industry are entering the development of cloud services. Several companies want to explore the possibilities and benefits of cloud computing, but with the amount of cloud computing services increasing quickly, the need

  16. LHC Report: out of the clouds (part II)

    CERN Multimedia

    Giovanni Rumolo for the LHC team

    2015-01-01

    A large fraction of the LHC beam-time over the last two weeks has been devoted to the second phase of the scrubbing of the vacuum chambers. This was aimed at reducing the formation of electron clouds in the beam pipes, this time performed with 25-nanosecond spaced bunches. This operation is designed to prepare the machine for a smooth intensity ramp-up for physics with this type of beam.   The scrubbing of the accelerator beam pipes is done by running the machine under an intense electron cloud regime while respecting beam stability constraints. When electron cloud production becomes sufficiently intense, the probability of creating secondary electrons at the chamber walls decreases and this inhibits the whole process. In this way, the scrubbing operation eventually reduces the formation of electron clouds, which would otherwise generate instabilities in the colliding beams. The second phase of LHC scrubbing started on Saturday, 25 July, when 25 ns beams were circulated again in the LHC...

  17. Cloud Computing (1/2)

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Cloud computing, the recent years buzzword for distributed computing, continues to attract and keep the interest of both the computing and business world. These lectures aim at explaining "What is Cloud Computing?" identifying and analyzing it's characteristics, models, and applications. The lectures will explore different "Cloud definitions" given by different authors and use them to introduce the particular concepts. The main cloud models (SaaS, PaaS, IaaS), cloud types (public, private, hybrid), cloud standards and security concerns will be presented. The borders between Cloud Computing and Grid Computing, Server Virtualization, Utility Computing will be discussed and analyzed.

  18. Cloud Computing (2/2)

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Cloud computing, the recent years buzzword for distributed computing, continues to attract and keep the interest of both the computing and business world. These lectures aim at explaining "What is Cloud Computing?" identifying and analyzing it's characteristics, models, and applications. The lectures will explore different "Cloud definitions" given by different authors and use them to introduce the particular concepts. The main cloud models (SaaS, PaaS, IaaS), cloud types (public, private, hybrid), cloud standards and security concerns will be presented. The borders between Cloud Computing and Grid Computing, Server Virtualization, Utility Computing will be discussed and analyzed.

  19. IBM SmartCloud essentials

    CERN Document Server

    Schouten, Edwin

    2013-01-01

    A practical, user-friendly guide that provides an introduction to cloud computing using IBM SmartCloud, along with a thorough understanding of resource management in a cloud environment.This book is great for anyone who wants to get a grasp of what cloud computing is and what IBM SmartCloud has to offer. If you are an IT specialist, IT architect, system administrator, or a developer who wants to thoroughly understand the cloud computing resource model, this book is ideal for you. No prior knowledge of cloud computing is expected.

  20. Laboratory investigation of nitrile ices of Titan's stratospheric clouds

    Science.gov (United States)

    Nna Mvondo, D.; Anderson, C. M.; McLain, J. L.; Samuelson, R. E.

    2017-09-01

    Titan's mid to lower stratosphere contains complex cloud systems of numerous organic ice particles comprised of both hydrocarbon and nitrile compounds. Most of these stratospheric ice clouds form as a result of vapor condensation formation processes. However, there are additional ice emission features such as dicyanoacetylene (C4N2) and the 220 cm-1 ice emission feature (the "Haystack") that are difficult to explain since there are no observed vapor emission features associated with these ices. In our laboratory, using a high-vacuum chamber coupled to a FTIR spectrometer, we are engaged in a dedicated investigation of Titan's stratospheric ices to interpret and constrain Cassini Composite InfraRed Spectrometer (CIRS) far-IR data. We will present laboratory transmittance spectra obtained for propionitrile (CH3CH2CN), cyanogen (C2N2) and hydrogen cyanide (HCN) ices, as well as various combinations of their mixtures, to better understand the cloud chemistry occurring in Titan's stratosphere.

  1. Cloud MicroAtlas∗

    Indian Academy of Sciences (India)

    ∗Any resemblance to the title of David Mitchell's book is purely intentional! RESONANCE | March 2017. 269 .... The most comprehensive reference we know of on the subject of cloud microphysics is the book .... Economic and. Political Weekly ...

  2. Green symbiotic cloud communications

    CERN Document Server

    Mustafa, H D; Desai, Uday B; Baveja, Brij Mohan

    2017-01-01

    This book intends to change the perception of modern day telecommunications. Communication systems, usually perceived as “dumb pipes”, carrying information / data from one point to another, are evolved into intelligently communicating smart systems. The book introduces a new field of cloud communications. The concept, theory, and architecture of this new field of cloud communications are discussed. The book lays down nine design postulates that form the basis of the development of a first of its kind cloud communication paradigm entitled Green Symbiotic Cloud Communications or GSCC. The proposed design postulates are formulated in a generic way to form the backbone for development of systems and technologies of the future. The book can be used to develop courses that serve as an essential part of graduate curriculum in computer science and electrical engineering. Such courses can be independent or part of high-level research courses. The book will also be of interest to a wide range of readers including b...

  3. Entangled Cloud Storage

    DEFF Research Database (Denmark)

    Ateniese, Giuseppe; Dagdelen, Özgür; Damgård, Ivan Bjerre

    2012-01-01

    keeps the files in it private but still lets each client P_i recover his own data by interacting with S; no cooperation from other clients is needed. At the same time, the cloud provider is discouraged from altering or overwriting any significant part of c as this will imply that none of the clients can......Entangled cloud storage enables a set of clients {P_i} to “entangle” their files {f_i} into a single clew c to be stored by a (potentially malicious) cloud provider S. The entanglement makes it impossible to modify or delete significant part of the clew without affecting all files in c. A clew...... recover their files. We provide theoretical foundations for entangled cloud storage, introducing the notion of an entangled encoding scheme that guarantees strong security requirements capturing the properties above. We also give a concrete construction based on privacy-preserving polynomial interpolation...

  4. Model calculations for the airborne Fast Ice Nuclei CHamber FINCH-HALO

    Science.gov (United States)

    Nillius, B.; Bingemer, H.; Bundke, U.; Jaenicke, R.; Reimann, B.; Wetter, T.

    2009-04-01

    Ice nuclei (IN) initiate the formation of primary ice in tropospheric clouds. In mixed phase clouds the primary ice crystals can grow very fast by the Bergeron-Findeisen process (Findeisen, 1938) at the expense of evaporating water droplets, and form precipitation. Thus, IN are essential for the development of precipitation in mixed phase clouds in the middle latitude. However, the role of IN in the development of clouds is still poorly understood and needs to be studied (Levin and Cotton, 2007). A Fast Ice Nuclei CHamber (FINCH-HALO) for airborne operation on the High And LOng Range research aircraft (HALO) is under development at the Institute for Atmosphere and Environment University Frankfurt. IN particles are activated within the chamber at certain ice super-saturation and temperature by mixing three gas flows, a warm moist, a cold dry, and an aerosol flow. After activation the particles will grow within a processing chamber. In an optical depolarisation detector droplets and ice crystals are detected separately. The setup of the new FINCH-HALO instrument is based on the ground based IN counter FINCH (Bundke, 2008). In FINCH-HALO a new cooling unit is used. Thus, measurements down to -40°C are possible. Furthermore minor changes of the inlet section where the mixing occurs were done. The contribution will present 3D model calculations with FLUENT of the flow conditions in the new inlet section for different pressure levels during a flight typical for HALO. Growth rates of ice crystals in the chamber at different temperature and super-saturation will be shown. References: Bundke U., B. Nillius, R. Jaenicke, T. Wetter, H. Klein, H. Bingemer, (2008). The Fast Ice Nucleus Chamber FINCH, Atmospheric Research, doi:10.1016/j.atmosres.2008.02.008 Findeisen, R., (1938). Meteorologisch-physikalische Begebenheiten der Vereisung in der Atmosphäre. Hauptversammlung 1938 der Lilienthal-Gesellschaft. Levin, Z., W. Cotton, (2007). Aerosol pollution impact on precipitation

  5. Marine Cloud Brightening

    Energy Technology Data Exchange (ETDEWEB)

    Latham, John; Bower, Keith; Choularton, Tom; Coe, H.; Connolly, P.; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Philip J.; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Robert

    2012-09-07

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could - subject to satisfactory resolution of technical and scientific problems identified herein - have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seedparticle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

  6. CLOUD COMPUTING SECURITY ISSUES

    OpenAIRE

    Florin OGIGAU-NEAMTIU

    2012-01-01

    The term “cloud computing” has been in the spotlights of IT specialists the last years because of its potential to transform this industry. The promised benefits have determined companies to invest great sums of money in researching and developing this domain and great steps have been made towards implementing this technology. Managers have traditionally viewed IT as difficult and expensive and the promise of cloud computing leads many to think that IT will now be easy and cheap. The reality ...

  7. Marine cloud brightening.

    Science.gov (United States)

    Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Phillip; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Rob

    2012-09-13

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could-subject to satisfactory resolution of technical and scientific problems identified herein-have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seed-particle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100×100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

  8. Cloud benchmarking for performance

    OpenAIRE

    Varghese, Blesson; Akgun, Ozgur; Miguel, Ian; Thai, Long; Barker, Adam

    2014-01-01

    Date of Acceptance: 20/09/2014 How can applications be deployed on the cloud to achieve maximum performance? This question has become significant and challenging with the availability of a wide variety of Virtual Machines (VMs) with different performance capabilities in the cloud. The above question is addressed by proposing a six step benchmarking methodology in which a user provides a set of four weights that indicate how important each of the following groups: memory, processor, computa...

  9. Toward Cloud Computing Evolution

    OpenAIRE

    Susanto, Heru; Almunawar, Mohammad Nabil; Kang, Chen Chin

    2012-01-01

    -Information Technology (IT) shaped the success of organizations, giving them a solid foundation that increases both their level of efficiency as well as productivity. The computing industry is witnessing a paradigm shift in the way computing is performed worldwide. There is a growing awareness among consumers and enterprises to access their IT resources extensively through a "utility" model known as "cloud computing." Cloud computing was initially rooted in distributed grid-based computing. ...

  10. A TRUSTWORTHY CLOUD FORENSICS ENVIRONMENT

    OpenAIRE

    Zawoad , Shams; Hasan , Ragib

    2015-01-01

    Part 5: CLOUD FORENSICS; International audience; The rapid migration from traditional computing and storage models to cloud computing environments has made it necessary to support reliable forensic investigations in the cloud. However, current cloud computing environments often lack support for forensic investigations and the trustworthiness of evidence is often questionable because of the possibility of collusion between dishonest cloud providers, users and forensic investigators. This chapt...

  11. On Cloud-based Oversubscription

    OpenAIRE

    Householder, Rachel; Arnold, Scott; Green, Robert

    2014-01-01

    Rising trends in the number of customers turning to the cloud for their computing needs has made effective resource allocation imperative for cloud service providers. In order to maximize profits and reduce waste, providers have started to explore the role of oversubscribing cloud resources. However, the benefits of cloud-based oversubscription are not without inherent risks. This paper attempts to unveil the incentives, risks, and techniques behind oversubscription in a cloud infrastructure....

  12. SOME CONSIDERATIONS ON CLOUD ACCOUNTING

    OpenAIRE

    Doina Pacurari; Elena Nechita

    2013-01-01

    Cloud technologies have developed intensively during the last years. Cloud computing allows the customers to interact with their data and applications at any time, from any location, while the providers host these resources. A client company may choose to run in the cloud a part of its business (sales by agents, payroll, etc.), or even the entire business. The company can get access to a large category of cloud-based software, including accounting software. Cloud solutions are especially reco...

  13. Venturi vacuum systems for hypobaric chamber operations.

    Science.gov (United States)

    Robinson, R; Swaby, G; Sutton, T; Fife, C; Powell, M; Butler, B D

    1997-11-01

    Physiological studies of the effects of high altitude on man often require the use of a hypobaric chamber to simulate the reduced ambient pressures. Typical "altitude" chambers in use today require complex mechanical vacuum systems to evacuate the chamber air, either directly or via reservoir system. Use of these pumps adds to the cost of both chamber procurement and maintenance, and service of these pumps requires trained support personnel and regular upkeep. In this report we describe use of venturi vacuum pumps to perform the function of mechanical vacuum pumps for human and experimental altitude chamber operations. Advantages of the venturi pumps include their relatively low procurement cost, small size and light weight, ease of installation and plumbing, lack of moving parts, and independence from electrical power sources, fossil fuels and lubricants. Conversion of three hyperbaric chambers to combined hyper/hypobaric use is described.

  14. Proportional chamber with data analog output

    International Nuclear Information System (INIS)

    Popov, V.E.; Prokof'ev, A.N.

    1977-01-01

    A proportional multiwier chamber is described. The chamber makes it possible to determine angles at wich a pion strikes a polarized target. A delay line, made of 60-core flat cable is used for removing signals from the chamber. From the delay line, signals are amplified and successively injected into shapers and a time-to-amplitude converter. An amplitude of the time-to amplitude converter output signal unambiguously determines the coordinate of a point at which a particle strikes the chamber plane. There are also given circuits of amplifiers, which consist of a preamplifier with gain 30 and a main amplifier with adjustable gain. Data on testing the chamber with the 450 MeV pion beam is demonstrated. The chamber features an efficiency of about 98 per cent under load of 2x10 5 s -1

  15. Legacies of the bubble chamber

    International Nuclear Information System (INIS)

    Mulvey, J.H.

    1994-01-01

    Legacies are what we pass on to those who follow us, the foundations on which the next advances in our science are being made; the things by which we shall be remembered, recorded in learned journals, written in the text books -food for the historians of science. This is not a summary, and it will draw no conclusions. It is a personal view which will look a little wider than the main physics results to include a mention of one or two of the technologies and methods handed on to both particle physics and other branches of sciences, a brief reference to bubble chamber pictures as aids in teaching, and a comment on the challenge now increasingly applied in the UK - and perhaps elsewhere -as a criterion for funding research: will it contribute to ''wealth creation''? (orig.)

  16. Picture chamber for radiographic system

    International Nuclear Information System (INIS)

    1977-01-01

    The picture chamber for a radiographic system is characterised by a base, a first electrode carried in the base, an X-ray irradiation window provided with an outer plate and an inner plate and a conducting surface which serves as a second electrode, which has a plate gripping it at each adjacent edge and which has at the sides a space which is occupied by a filling material, maintained at a steady pressure, by means of the mounting against the base and wherein the inner plate lies against the first electrode and which is provided with a split, and with means for the separation of the split in the area of the inner plate so that a fluid may be retained in the split. (G.C.)

  17. Drift chamber data readout system

    International Nuclear Information System (INIS)

    Basiladze, S.G.; Lokhonyai, L.

    1980-01-01

    An electronic system for processing drift chamber signals is described. The system consists of 4-channel fast amplifier-discriminators of low threshold, 16-channel time-expanders transforming 0.5 μs time intervals to 10 μs and a 9-bit time-to-digital converter (TDC) recording up to 16 expanded time intervals. If the average track multiplicity is small, TDC is capable to process signals from 4 time-expanders (i.e., 64 drift gaps). In order to record multiple tracks per drift gap discriminator outputs can be connected to a number of time-expander channels. The fast clear input enables the system to be cleared within 0.5 μs. Efficient readout from TDC is facilated by reading only those channels which contain non-zero data (9 bits - drift time; 6 bits - wire number)

  18. The CAST Time Projection Chamber

    CERN Document Server

    Autiero, D.; Carmona, J.M.; Cebrian, S.; Chesi, E.; Davenport, M.; Delattre, M.; Di Lella, L.; Formenti, F.; Irastorza, I.G.; Gomez, H.; Hasinoff, M.; Lakic, B.; Luzon, G.; Morales, J.; Musa, L.; Ortiz, A.; Placci, A.; Rodriguez, A.; Ruz, J.; Villar, J.A.; Zioutas, K.

    2007-01-01

    One of the three X-ray detectors of the CAST experiment searching for solar axions is a Time Projection Chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity X-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is safely set during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62 %. Shielding has been installed around the detector, lowering the background level to 4.10 x 10^-5 counts/cm^2/s/keV between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion-photon coupling and mass.

  19. CLOUD COMPUTING TECHNOLOGY TRENDS

    Directory of Open Access Journals (Sweden)

    Cristian IVANUS

    2014-05-01

    Full Text Available Cloud computing has been a tremendous innovation, through which applications became available online, accessible through an Internet connection and using any computing device (computer, smartphone or tablet. According to one of the most recent studies conducted in 2012 by Everest Group and Cloud Connect, 57% of companies said they already use SaaS application (Software as a Service, and 38% reported using standard tools PaaS (Platform as a Service. However, in the most cases, the users of these solutions highlighted the fact that one of the main obstacles in the development of this technology is the fact that, in cloud, the application is not available without an Internet connection. The new challenge of the cloud system has become now the offline, specifically accessing SaaS applications without being connected to the Internet. This topic is directly related to user productivity within companies as productivity growth is one of the key promises of cloud computing system applications transformation. The aim of this paper is the presentation of some important aspects related to the offline cloud system and regulatory trends in the European Union (EU.

  20. Experimental evidence for millisecond activation timescales using the Fast IN Chamber (FINCH) measurements

    Science.gov (United States)

    Bundke, U.; Jaenicke, R.; Klein, H.; Nillius, B.; Reimann, B.; Wetter, T.; Bingemer, H.

    2009-04-01

    Ice formation in clouds is a subject of great practical and fundamental importance since the occurrence of ice particle initializes dramatic changes in the microphysical structure of the cloud, which finally ends in the formation of precipitation. The initially step of ice formation is largely unknown. Homogenous nucleation of ice occurs only below -40 °C. If an ice nucleus (IN) is present, heterogeneous nucleation may occur at higher temperature. Here deposition freezing, condensation and immersion freezing as well as contact freezing are known. Also growth rates of ice particles are known as function of crystal surface properties, temperature and super saturation. Timescales for homogenous freezing activation in the order of 0.01 seconds and nucleation rates have been measured by Anderson et al. (1980) and Hagen et al., (1981) using their expansion cloud chamber. This contribution of deposition mode freezing measurements by the ice nucleus counter FINCH presents evidence that the activation timescale of this freezing mode is in the order of 1E-3 seconds. FINCH is an Ice Nucleus counter which activates IN in a supersaturated environment at freezing temperatures. The activation conditions are actively controlled by mixing three gas flows (aerosol, particle-free cold-dry and warm-humid flows).See Bundke et al. 2008 for details. In a special operation mode of FINCH we are able to produce a controlled peak super saturation in the order of 1 ms duration. For several test aerosols the results observed in this particular mode are comparable to normal mode operations, where the maximum super saturation remains for more than a second, thus leading to the conclusion that the time for activation is in the order of 1ms or less. References: R.J. Anderson et al, "A Study of Homogeneous Condensation Freezing Nucleation of Small Water Droplets in an Expansion Cloud Chamber, Journal of the Atmospheric Sciences, Vol. 37, 2508-2520, 1980 U.Bundke et al., "The fast Ice Nucleus

  1. Construction and performance of large flash chambers

    International Nuclear Information System (INIS)

    Taylor, F.E.; Bogert, D.; Fisk, R.; Stutte, L.; Walker, J.K.; Wolfson, J.; Abolins, M.; Ernwein, J.; Owen, D.; Lyons, T.

    1979-01-01

    The construction and performance of 12' x 12' flash chambers used in a 340 ton neutrino detector under construction at Fermilab is described. The flash chambers supply digital information with a spatial resolution of 0.2'', and are used to finely sample the shower development of the reaction products of neutrino interactions. The flash chambers are easy and inexpensive to build and are electronically read out

  2. Track photographing in 8-m streamer chamber

    International Nuclear Information System (INIS)

    Anisimova, N.Z.; Davidenko, V.A.; Kantserov, V.A.; Rybakov, V.G.; Somov, S.V.

    1981-01-01

    A system for obtaining data from a streamer chamber intended for measuring muon polarization is described. An optical scheme for photographing of tracks in the chamber is given. The photographing process is complicated at the expense of large dimensions and module structure of the chamber as well as due to insufficient for direct photographing brightness of streamers. The system described was tested during a long time in a physical experiment. More than 100 thousand photos have been taken by its means [ru

  3. Drift chamber tracking with neural networks

    International Nuclear Information System (INIS)

    Lindsey, C.S.; Denby, B.; Haggerty, H.

    1992-10-01

    We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed

  4. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    To minimize eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical stength, it was corrugated in a hydro-forming process. The chamber is curved, to follow the beam's orbital path. Under vacuum, the chamber tends to staighten, the ceramic spacer along half of its length keeps it in place (see also 7402458).

  5. Device for gamma-chamber transducer alignment

    International Nuclear Information System (INIS)

    Mirkhodzhaev, A.Kh.; Kuznetsov, N.K.; Ostryj, Yu.E.

    1987-01-01

    The device consists of the upper part of the gamma chamber pilar to which a rod is rigidly fastened with a disk of acrylic plastic moving freely on the opposite end. The disk is placed coaxially and is equal to the gamma chamber detector crystal. The device makes it possible to use ordinary medical couches covered with a porolone mattress when the gamma chamber detector is placed below

  6. Bubble chamber: Omega production and decay

    CERN Document Server

    1973-01-01

    This image is taken from one of CERN's bubble chambers and shows the decay of a positive kaon in flight. The decay products of this kaon can be seen spiraling in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that has been heated to boiling point.

  7. Bicone vacuum chamber for ISR intersection

    CERN Multimedia

    1975-01-01

    This is one of the bicone chambers made of titanium for experiment R 702. The central corrugated part had a very thin titanium wall (0.28 mm). The first of these chambers collapsed in its central part when baked at 300 C (August 1975). After an intensive effort to develop better quality and reproducible welds for this special material, the ISR workshop was able to build two new chambers of this type. One of them was installed at I 7 for R 702 in 1976 and worked perfectly. It was at that time the most "transparent" intersection vacuum chamber. See also 7609219, 7609221.

  8. The Mark II Vertex Drift Chamber

    International Nuclear Information System (INIS)

    Alexander, J.P.; Baggs, R.; Fujino, D.

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 μm spatial resolution and 2 gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO 2 mixtures are presented. 10 refs., 12 figs., 1 tab

  9. Investigation of very long jet chambers

    Energy Technology Data Exchange (ETDEWEB)

    Burckhart, H J; Va' vra, J; Zankel, K; Dudziak, U; Schaile, D; Schaile, O; Igo-Kemenes, P; Lennert, P

    1986-04-01

    The electrostatic properties and the performances of very long jet chambers have been investigated. Using 100 MHz FADC wave form digitisers, the tracking accuracy, the charge division and the dE/dx performance of two chambers, one with 4.5 m long tungsten wires and one with 4 m long highly resistive ''NiCoTi'' wires have been studied. The geometry of the chambers was chosen to define some of the design parameters of the jet chamber for the OPAL detector for LEP. (orig.).

  10. Investigation of very long jet chambers

    Energy Technology Data Exchange (ETDEWEB)

    Burckhart, H J; Va' vra, J; Zankel, K; Dudziak, U; Schaile, D; Schaile, O; Igo-Kemenes, P; Lennert, P

    1986-04-01

    The electrostatic properties and the performances of very long jet chambers have been investigated. Using 100 MHz FADC wave form digitisers, the tracking accuracy, the charge division and the dE/dx performance of two chambers, one with 4.5 m long tungsten wires and one with 4 m long highly resistive ''NiCoTi'' wires have been studied. The geometry of the chambers was chosen to define some of the design parameters of the jet chamber for the OPAL detector for LEP.

  11. Cylindrical ionization chamber with compressed krypton

    International Nuclear Information System (INIS)

    Kuz'minov, V.V.; Novikov, V.M.; Pomanskii, A.A.; Pritychenko, B.V.; Viyar, J.; Garcia, E.; Morales, A.; Morales, J.; Nunes-Lagos, R.; Puimedon, J.; Saens, K.; Salinas, A.; Sarsa, M.

    1993-01-01

    A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78 Kr. Krypton is the working gas material of the chamber. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. The energy resolution is 2.1% for an energy of 1.84 MeV (the source of γ-quanta is 88 Y) when the chamber is filled with a mixture of Kr+0.2% H 2 under a pressure of 25 atm

  12. D0 central tracking chamber performance studies

    International Nuclear Information System (INIS)

    Pizzuto, D.

    1991-12-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an RΦ tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against γ → e + e - events

  13. Precision Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs measurements and calibration of antennas for satellites and aircraft or groundbased systems. The chamber is primarily used for optimizing antenna...

  14. Cloud networking understanding cloud-based data center networks

    CERN Document Server

    Lee, Gary

    2014-01-01

    Cloud Networking: Understanding Cloud-Based Data Center Networks explains the evolution of established networking technologies into distributed, cloud-based networks. Starting with an overview of cloud technologies, the book explains how cloud data center networks leverage distributed systems for network virtualization, storage networking, and software-defined networking. The author offers insider perspective to key components that make a cloud network possible such as switch fabric technology and data center networking standards. The final chapters look ahead to developments in architectures

  15. Photoelectron Yield and Photon Reflectivity from Candidate LHC Vacuum Chamber Materials with Implications to the Vacuum Chamber Design

    CERN Document Server

    Baglin, V; Gröbner, Oswald

    1998-01-01

    Studies of the photoelectron yield and photon reflectivity at grazing incidence (11 mrad) from candidate LHC vacuum chamber materials have been made on a dedicated beam line on the Electron Positron A ccumulator (EPA) ring at CERN. These measurements provide realistic input toward a better understanding of the electron cloud phenomena expected in the LHC. The measurements were made using synchrotro n radiation with critical photon energies of 194 eV and 45 eV; the latter corresponding to that of the LHC at the design energy of 7 TeV. The test materials are mainly copper, either, i) coated by co- lamination or by electroplating onto stainless steel, or ii) bulk copper prepared by special machining. The key parameters explored were the effect of surface roughness on the reflectivity and the pho toelectron yield at grazing photon incidence, and the effect of magnetic field direction on the yields measured at normal photon incidence. The implications of the results on the electron cloud phenom ena, and thus the L...

  16. Marine cloud brightening

    Science.gov (United States)

    Latham, John; Bower, Keith; Choularton, Tom; Coe, Hugh; Connolly, Paul; Cooper, Gary; Craft, Tim; Foster, Jack; Gadian, Alan; Galbraith, Lee; Iacovides, Hector; Johnston, David; Launder, Brian; Leslie, Brian; Meyer, John; Neukermans, Armand; Ormond, Bob; Parkes, Ben; Rasch, Phillip; Rush, John; Salter, Stephen; Stevenson, Tom; Wang, Hailong; Wang, Qin; Wood, Rob

    2012-01-01

    The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could—subject to satisfactory resolution of technical and scientific problems identified herein—have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seed-particle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud–albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100×100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action

  17. USGEO DMWG Cloud Computing Recommendations

    Science.gov (United States)

    de la Beaujardiere, J.; McInerney, M.; Frame, M. T.; Summers, C.

    2017-12-01

    The US Group on Earth Observations (USGEO) Data Management Working Group (DMWG) has been developing Cloud Computing Recommendations for Earth Observations. This inter-agency report is currently in draft form; DMWG hopes to have released the report as a public Request for Information (RFI) by the time of AGU. The recommendations are geared toward organizations that have already decided to use the Cloud for some of their activities (i.e., the focus is not on "why you should use the Cloud," but rather "If you plan to use the Cloud, consider these suggestions.") The report comprises Introductory Material, including Definitions, Potential Cloud Benefits, and Potential Cloud Disadvantages, followed by Recommendations in several areas: Assessing When to Use the Cloud, Transferring Data to the Cloud, Data and Metadata Contents, Developing Applications in the Cloud, Cost Minimization, Security Considerations, Monitoring and Metrics, Agency Support, and Earth Observations-specific recommendations. This talk will summarize the recommendations and invite comment on the RFI.

  18. Cloud GIS Based Watershed Management

    Science.gov (United States)

    Bediroğlu, G.; Colak, H. E.

    2017-11-01

    In this study, we generated a Cloud GIS based watershed management system with using Cloud Computing architecture. Cloud GIS is used as SAAS (Software as a Service) and DAAS (Data as a Service). We applied GIS analysis on cloud in terms of testing SAAS and deployed GIS datasets on cloud in terms of DAAS. We used Hybrid cloud computing model in manner of using ready web based mapping services hosted on cloud (World Topology, Satellite Imageries). We uploaded to system after creating geodatabases including Hydrology (Rivers, Lakes), Soil Maps, Climate Maps, Rain Maps, Geology and Land Use. Watershed of study area has been determined on cloud using ready-hosted topology maps. After uploading all the datasets to systems, we have applied various GIS analysis and queries. Results shown that Cloud GIS technology brings velocity and efficiency for watershed management studies. Besides this, system can be easily implemented for similar land analysis and management studies.

  19. Security Problems in Cloud Computing

    Directory of Open Access Journals (Sweden)

    Rola Motawie

    2016-12-01

    Full Text Available Cloud is a pool of computing resources which are distributed among cloud users. Cloud computing has many benefits like scalability, flexibility, cost savings, reliability, maintenance and mobile accessibility. Since cloud-computing technology is growing day by day, it comes with many security problems. Securing the data in the cloud environment is most critical challenges which act as a barrier when implementing the cloud. There are many new concepts that cloud introduces, such as resource sharing, multi-tenancy, and outsourcing, create new challenges for the security community. In this work, we provide a comparable study of cloud computing privacy and security concerns. We identify and classify known security threats, cloud vulnerabilities, and attacks.

  20. Cloud type comparisons of AIRS, CloudSat, and CALIPSO cloud height and amount

    Directory of Open Access Journals (Sweden)

    B. H. Kahn

    2008-03-01

    Full Text Available The precision of the two-layer cloud height fields derived from the Atmospheric Infrared Sounder (AIRS is explored and quantified for a five-day set of observations. Coincident profiles of vertical cloud structure by CloudSat, a 94 GHz profiling radar, and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO, are compared to AIRS for a wide range of cloud types. Bias and variability in cloud height differences are shown to have dependence on cloud type, height, and amount, as well as whether CloudSat or CALIPSO is used as the comparison standard. The CloudSat-AIRS biases and variability range from −4.3 to 0.5±1.2–3.6 km for all cloud types. Likewise, the CALIPSO-AIRS biases range from 0.6–3.0±1.2–3.6 km (−5.8 to −0.2±0.5–2.7 km for clouds ≥7 km (<7 km. The upper layer of AIRS has the greatest sensitivity to Altocumulus, Altostratus, Cirrus, Cumulonimbus, and Nimbostratus, whereas the lower layer has the greatest sensitivity to Cumulus and Stratocumulus. Although the bias and variability generally decrease with increasing cloud amount, the ability of AIRS to constrain cloud occurrence, height, and amount is demonstrated across all cloud types for many geophysical conditions. In particular, skill is demonstrated for thin Cirrus, as well as some Cumulus and Stratocumulus, cloud types infrared sounders typically struggle to quantify. Furthermore, some improvements in the AIRS Version 5 operational retrieval algorithm are demonstrated. However, limitations in AIRS cloud retrievals are also revealed, including the existence of spurious Cirrus near the tropopause and low cloud layers within Cumulonimbus and Nimbostratus clouds. Likely causes of spurious clouds are identified and the potential for further improvement is discussed.

  1. Electron Cloud Buildup Characterization Using Shielded Pickup Measurements and Custom Modeling Code at CESRTA

    CERN Document Server

    Crittenden, James A

    2013-01-01

    The Cornell Electron Storage Ring Test Accelerator experimental program includes investigations into electron cloud buildup, applying various mitigation techniques in custom vacuum chambers. Among these are two 1.1-m-long sections located symmetrically in the east and west arc regions. These chambers are equipped with pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of small holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. Carbon-coated, TiN-coated and uncoated aluminum chambers have been tested. Electron and positron beams of 2.1, 4.0 and 5.3 GeV with a variety of bunch populations and spacings in steps of 4 and 14 ns have been used. Here we report on results from the ECLOUD modeling code which highlight the sensitivity of these measurements to the physical phenomena determining cloud buildup such as the photoelectron produ...

  2. Relating cloud condensation nuclei activity and oxidation level of alpha-pinene secondary organic aerosols

    DEFF Research Database (Denmark)

    Foverskov, Mia Frosch Mogensbæk; Bilde, M.; DeCarlo, P. F.

    2011-01-01

    During a series of smog chamber experiments, the effects of chemical and photochemical aging on the ability of organic aerosols generated from ozonolysis of alpha-pinene to act as cloud condensation nuclei (CCN) were investigated. In particular, the study focused on the relation between oxygenation...

  3. Results from the CERN pilot CLOUD experiment

    International Nuclear Information System (INIS)

    Duplissy, J.; David, A.; Hahn, F.; Kirkby, J.; Onnela, A.; Veenhof, R.; Wilhelmsson, M.; Enghoff, M.B.; Avngaard, M.; Bondo, T.; Marsh, N.D.; Pedersen, O.P.; Polny, J.; Svensmark, H.; Svensmark, J.; Aplin, K.L.; Bingham, R.; Kellett, B.; Lockwood, M.; Arnold, F.; Aufmhoff, H.; Reichl, U.; Verheggen, B.; Baltensperger, U.; Wehrle, G.; Weingartner, E.; Carslaw, K.; Curtius, J.; Fastrup, B.; Pedersen, E.; Gagne, S.; Kulmala, M.; Laakso, L.; Nieminen, T.; Sipila, M.; Harrison, R.G.; Laaksonen, A.; Lillestol, E.; Makela, J.; Makhmutov, V.; Stozhkov, Y.; Seinfeld, J.H.; Stratmann, F.; Wex, H.; Viisanen, Y.; Wagner, P.E.; Winkler, P.M.

    2010-01-01

    During a 4-week run in October-November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving Outdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm -3 s -1 , and growth rates between 2 and 37 nm h -1 . The corresponding H2SO4 concentrations were typically around 106 cm -3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analyzing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most

  4. Raymond J. Chambers--A Personal Reflection

    Science.gov (United States)

    Gaffikin, Michael

    2012-01-01

    This paper is presented as a tribute to Raymond J. Chambers. As its title suggests, it is a personal reflection through the eyes of someone who worked closely with him over a period of 10 years during a latter part of his career, and who completed a doctoral thesis with aspects of the work of Chambers as its subject. During this time, author…

  5. Investigation of a multiwire proportional chamber

    International Nuclear Information System (INIS)

    Konijn, J.

    1976-01-01

    The article discusses some aspects of a prototype multiwire proportional chamber for electron detection located at IKO in Amsterdam, i.e. voltage, counting rates, noise and gas mixture (argon, ethylene bromide). The efficiency and performance of the chamber have been investigated and an error analysis is given

  6. Results from the MAC Vertex chamber

    International Nuclear Information System (INIS)

    Nelson, H.N.

    1987-05-01

    The design, construction, and performance characteristics of a high precision gaseous drift chamber made of thin walled proportional tubes are described. The device achieved an average spatial resolution of 45 μm in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed

  7. Dual-chamber inflatable oil boom

    International Nuclear Information System (INIS)

    Blair, R.M.; Tedeschi, E.T.

    1993-01-01

    An elongated floating material containment boom section is described having a normally vertical ballasted skirt depending from flotation means, and convertible from a flattened collapsed condition to a deployable condition wherein buoyancy chamber means extending along the upper edge of said skirt are inflated to expanded buoyant configuration, including: a gas-impervious sleeve extending along the upper edge of said normally vertical skirt forming a first outer collapsible and inflatable flotation chamber, a first inflation valve connecting the interior of said sleeve with the ambient atmosphere, through which gas under pressure may be introduced into said sleeve to inflate said first buoyant outer flotation chamber, elongated gas-impervious tube means positioned inside said outer flotation chamber and forming second collapsible and inflatable internal flotation bladder chamber means, second inflation valve means connecting the interior of said bladder means through said outer flotation chamber to the ambient atmosphere through which gas under pressure may be introduced into said bladder means to inflate it forming said second flotation chamber means inside said outer flotation chamber

  8. An ionization chamber with magnetic levitated electrodes

    CERN Document Server

    Kawaguchi, T

    1999-01-01

    A new type of ionization chamber which has magnetically levitated electrodes has been developed. The electrodes are supplied voltages for the repelling of ions by a battery which is also levitated with the electrodes. The characteristics of this ionization chamber are investigated in this paper.

  9. HVAC&R Equipment Environmental Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — Description:Large "Truck" ChamberThe large "truck" chamber provides controlled air conditions from -7 °C (20 °F) to 65 °C (150 °F).Air-Conditioner and Heat Pump Test...

  10. USE OF GROWTH CHAMBERS FOR CABBAGE BREEDING

    Directory of Open Access Journals (Sweden)

    L. L. Bondareva

    2014-01-01

    Full Text Available Use of the growth chambers for cabbage breeding allows the reducing of certain stages of the breeding process and the growing biennial varieties of cabbage in a one-year cycle. In these growth chambers, the nutritional conditions, temperature, and lighting of plants are under control; the open pollination is eliminated.

  11. OPAL jet chamber full-scale prototype

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, H M; Hauschild, M; Hartmann, H; Hegerath, A; Boerner, H; Burckhart, H J; Dittmar, M; Hammarstroem, R; Heuer, R D; Mazzone, L

    1986-12-01

    The concept of a jet chamber for the central detector of OPAL was tested with a full scale prototype. The design of this prototype, its mechanical and electrical structure and its support system for high voltage, gas, laser calibration, and readout are described. Operating experience was gathered since summer 1984. The chamber performance in terms of spatial resolution and particle identification capability is given.

  12. 21 CFR 866.2120 - Anaerobic chamber.

    Science.gov (United States)

    2010-04-01

    ... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a device intended for medical purposes to maintain an anaerobic (oxygen...

  13. Triangular tube proportional wire chamber system

    Energy Technology Data Exchange (ETDEWEB)

    Badtke, D H; Bakken, J A; Barnett, B A; Blumenfeld, B J; Chien, C Y; Madansky, L; Matthews, J A.J.; Pevsner, A; Spangler, W J [Johns Hopkins Univ., Baltimore, MD (USA); Lee, K L [California Univ., Berkeley (USA). Lawrence Berkeley Lab.

    1981-10-15

    We report on the characteristics of the proportional tube chamber system which has been constructed for muon identification in the PEP-4 experiment at SLAC. The mechanical and electrical properties of the extruded aluminum triangular tubes allow these detectors to be used as crude drift chambers.

  14. Neutron induced current pulses in fission chambers

    International Nuclear Information System (INIS)

    Taboas, A.L.; Buck, W.L.

    1978-01-01

    The mechanism of neutron induced current pulse generation in fission chambers is discussed. By application of the calculated detector transfer function to proposed detector current pulse shapes, and by comparison with actually observed detector output voltage pulses, a credible, semi-empirical, trapezoidal pulse shape of chamber current is obtained

  15. Shielding Effectiveness Measurements using a Reverberation Chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes; Bergsma, J.G.; Bergsma, Hans; van Etten, Wim

    2006-01-01

    Shielding effectiveness measurements have been performed using a reverberation chamber. The reverberation chamber methodology as we1l as the measurement setup is described and some results are given. Samples include glass reinforced plastic panels, aluminum panels with many holes, wire mesh, among

  16. Counting the clouds

    International Nuclear Information System (INIS)

    Randall, David A

    2005-01-01

    Cloud processes are very important for the global circulation of the atmosphere. It is now possible, though very expensive, to simulate the global circulation of the atmosphere using a model with resolution fine enough to explicitly represent the larger individual clouds. An impressive preliminary calculation of this type has already been performed by Japanese scientists, using the Earth Simulator. Within the next few years, such global cloud-resolving models (GCRMs) will be applied to weather prediction, and later they will be used in climatechange simulations. The tremendous advantage of GCRMs, relative to conventional lowerresolution global models, is that GCRMs can avoid many of the questionable 'parameterizations' used to represent cloud effects in lower-resolution global models. Although cloud microphysics, turbulence, and radiation must still be parameterized in GCRMs, the high resolution of a GCRM simplifies these problems considerably, relative to conventional models. The United States currently has no project to develop a GCRM, although we have both the computer power and the expertise to do it. A research program aimed at development and applications of GCRMs is outlined

  17. Trust management in cloud services

    CERN Document Server

    Noor, Talal H; Bouguettaya, Athman

    2014-01-01

    This book describes the design and implementation of Cloud Armor, a novel approach for credibility-based trust management and automatic discovery of cloud services in distributed and highly dynamic environments. This book also helps cloud users to understand the difficulties of establishing trust in cloud computing and the best criteria for selecting a service cloud. The techniques have been validated by a prototype system implementation and experimental studies using a collection of real world trust feedbacks on cloud services.The authors present the design and implementation of a novel pro

  18. Scale analysis of convective clouds

    Directory of Open Access Journals (Sweden)

    Micha Gryschka

    2008-12-01

    Full Text Available The size distribution of cumulus clouds due to shallow and deep convection is analyzed using satellite pictures, LES model results and data from the German rain radar network. The size distributions found can be described by simple power laws as has also been proposed for other cloud data in the literature. As the observed precipitation at ground stations is finally determined by cloud numbers in an area and individual sizes and rain rates of single clouds, the cloud size distributions might be used for developing empirical precipitation forecasts or for validating results from cloud resolving models being introduced to routine weather forecasts.

  19. The CAST time projection chamber

    International Nuclear Information System (INIS)

    Autiero, D; Beltran, B; Carmona, J M; Cebrian, S; Chesi, E; Davenport, M; Delattre, M; Di Lella, L; Formenti, F; Irastorza, I G; Gomez, H; Hasinoff, M; Lakic, B; Luzon, G; Morales, J; Musa, L; Ortiz, A; Placci, A; Rodrigurez, A; Ruz, J; Villar, J A; Zioutas, K

    2007-01-01

    One of the three x-ray detectors of the CERN Axion Solar Telescope (CAST) experiment searching for solar axions is a time projection chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity x-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is set to a safe level during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62%. Shielding has been installed around the detector, lowering the background level to 4.10 x 10 -5 counts cm -2 s -1 keV -1 between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion-photon coupling and mass

  20. Neutron-sensitive ionization chamber

    International Nuclear Information System (INIS)

    Mayer, W.

    1978-01-01

    The neutron-sensitive ionization chamber which is to be applied for BWRs consists of a cylindrical outer electrode, closed at the ends, and a concentrically arranged inner electrode. It is designed as a hollow tube and coated with uranium on the outside. The reaction space lies between the two electrodes. The electrical connection is obtained through a coaxial cable whose nickel helix is properly intorduced into the inner electrode made of titanium or nickel. The sheathing respectively external conductor of the cable has got the same diameter as the outer electrode and is butt-welded to it. Between the cable helix and the sheathing there is filled Al 2 O 3 powder. The reaction space is sealed against the cable by means of a little tube pushed over the internal conductor resp. the helix. It consists of Ni resp. Al 2 O 3 which is coated on the outside at first by a layer of Al 2 O 3 and a layer of Ni resp. by a metal layer on the inside and on the outside. (DG) [de

  1. Multispecimen dual-beam irradiation damage chamber

    International Nuclear Information System (INIS)

    Packan, N.H.; Buhl, R.A.

    1980-06-01

    An irradiation damage chamber that can be used to rapidly simulate fast neutron damage in fission or fusion materials has been designed and constructed. The chamber operates in conjunction with dual Van de Graaff accelerators at ORNL to simulate a wide range of irradiation conditions, including pulsed irradiation. Up to six experiments, each with up to nine 3-mm disk specimens, can be loaded into the ultrahigh vacuum chamber. Specimen holders are heated with individual electron guns, and the temperature of each specimen can be monitored during bombardment by an infrared pyrometer. Three different dose levels may be obtained during any single bombardment, and the heavy-ion flux on each of the nine specimens can be measured independently with only a brief interruption of the beam. The chamber has been in service for nearly three years, during which time approximately 250 bombardments have been successfully carried out. An appendix contains detailed procedures for operating the chamber

  2. Wet drift chambers for precise luminosity

    International Nuclear Information System (INIS)

    Anderson, B.E.; Kennedy, B.W.; Ahmet, K.; Attree, D.J.; Barraclough, G.A.; Cresswell, M.J.; Hayes, D.A.; Miller, D.J.; Selby, C.; Sherwood, P.

    1994-01-01

    A set of high-precision compact drift chambers has been a vital component of the OPAL luminosity monitor since the start of data-taking at LEP. They were augmented in 1992 by the addition of Small Angle Reference Chambers with a very similar design to the original chamber. The performance of the chambers is reviewed, highlighting both the importance of using polyalkylene glycol (Breox) to maintain a uniform and parallel electric field and the construction techniques used to sustain the required field strength. We describe some of the operating problems, with their solutions, and show how the chambers have been used in achieving a systematic error of 0.41% on the luminosity measurement. ((orig.))

  3. Structural Analysis of Extended Plasma Focus Chamber

    International Nuclear Information System (INIS)

    Mohd Azhar Ahmad; Abdul Halim Baijan; Siti Aiasah Hashim

    2016-01-01

    Accelerator Development Centre (ADC) of Nuclear Malaysia intends to upgrade the plasma focus device. It involves the extension part placed on top of the existing plasma focus vacuum chamber. This extended vacuum chamber purposely to give an extra space in conducting experiments on the existing plasma focus chamber. The aim of upgrading the plasma focus device is to solve the limitation in research and analysis of sample due to its done in an open system that cause analysis of samples is limited and less optimal. This extended chamber was design in considering the ease of fabrication as well as durability of its structural. Thus, this paper discusses the structural analysis in term of pressure loading effect in extended chamber. (author)

  4. Note: Small anaerobic chamber for optical spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chauvet, Adrien A. P., E-mail: adrien.chauvet@gmail.com; Chergui, Majed [Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Spectroscopie Ultrarapide, ISIC, Faculté des Sciences de Base, Station 6, 1015 Lausanne (Switzerland); Agarwal, Rachna; Cramer, William A. [Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 (United States)

    2015-10-15

    The study of oxygen-sensitive biological samples requires an effective control of the atmosphere in which they are housed. In this aim however, no commercial anaerobic chamber is adequate to solely enclose the sample and small enough to fit in a compact spectroscopic system with which analysis can be performed. Furthermore, spectroscopic analysis requires the probe beam to pass through the whole chamber, introducing a requirement for adequate windows. In response to these challenges, we present a 1 l anaerobic chamber that is suitable for broad-band spectroscopic analysis. This chamber has the advantage of (1) providing access, via a septum, to the sample and (2) allows the sample position to be adjusted while keeping the chamber fixed and hermetic during the experiment.

  5. The Boycott effect in magma chambers

    Science.gov (United States)

    Blanchette, F.; Peacock, T.; Bush, J. W. M.

    2004-03-01

    We investigate the plausibility of the stratified Boycott effect as a source of layering in magma chambers. Crystal settling within the magma chamber will generate buoyant fluid near the sloping sidewalls whose vertical ascent may be limited by the ambient stratification associated with vertical gradients in SiO2. The resulting flow may be marked by a layered structure, each layer taking the form of a convection cell spanning the lateral extent of the magma chamber. Using parameters relevant to magma chambers, we estimate that such convection cells would be established over a timescale of a month and have a depth on the order of 4m, which is roughly consistent with field observations of strata within solidified chambers.

  6. Moving HammerCloud to CERN's private cloud

    CERN Document Server

    Barrand, Quentin

    2013-01-01

    HammerCloud is a testing framework for the Worldwide LHC Computing Grid. Currently deployed on about 20 hand-managed machines, it was desirable to move it to the Agile Infrastructure, CERN's OpenStack-based private cloud.

  7. Modeling of Cloud/Radiation Processes for Cirrus Cloud Formation

    National Research Council Canada - National Science Library

    Liou, K

    1997-01-01

    This technical report includes five reprints and pre-prints of papers associated with the modeling of cirrus cloud and radiation processes as well as remote sensing of cloud optical and microphysical...

  8. Time-resolved Shielded-Pickup Measurements and Modeling of Beam Conditioning Effects on Electron Cloud Buildup at CesrTA

    CERN Document Server

    Crittenden, J A; Liu, X; Palmer, M A; Santos, S; Sikora, J P; Kato, S; Calatroni, S; Rumolo, G

    2012-01-01

    The Cornell Electron Storage Ring Test Accelerator program includes investigations into electron cloud buildup in vacuum chambers with various coatings. Two 1.1-mlong sections located symmetrically in the east and west arc regions are equipped with BPM-like pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of 0.76 mm-diameter holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. We present new measurements of the effect of beam conditioning on a newly-installed amorphous carbon coated chamber, as well as on an extensively conditioned chamber with a diamond-like carbon coating. The ECLOUD modeling code is used to quantify the sensitivity of these measurements to model parameters, differentiating between photoelectron and secondary-electron production processes.

  9. Tharsis Limb Cloud

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Annotated image of Tharsis Limb Cloud 7 September 2005 This composite of red and blue Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) daily global images acquired on 6 July 2005 shows an isolated water ice cloud extending more than 30 kilometers (more than 18 miles) above the martian surface. Clouds such as this are common in late spring over the terrain located southwest of the Arsia Mons volcano. Arsia Mons is the dark, oval feature near the limb, just to the left of the 'T' in the 'Tharsis Montes' label. The dark, nearly circular feature above the 'S' in 'Tharsis' is the volcano, Pavonis Mons, and the other dark circular feature, above and to the right of 's' in 'Montes,' is Ascraeus Mons. Illumination is from the left/lower left. Season: Northern Autumn/Southern Spring

  10. Transition to the Cloud

    DEFF Research Database (Denmark)

    Hedman, Jonas; Xiao, Xiao

    2016-01-01

    The rising of cloud computing has dramatically changed the way software companies provide and distribute their IT product and related services over the last decades. Today, most software is bought offthe-shelf and distributed over the Internet. This transition is greatly influencing how software...... companies operate. In this paper, we present a case study of an ERP vendor for SMB (small and mediumsize business) in making a transition towards a cloud-based business model. Through the theoretical lens of ecosystem, we are able to analyze the evolution of the vendor and its business network as a whole......, and find that the relationship between vendor and Value-added-Reseller (VAR) is greatly affected. We conclude by presenting critical issues and challenges for managing such cloud transition....

  11. The photoevaporation of interstellar clouds

    International Nuclear Information System (INIS)

    Bertoldi, F.

    1989-01-01

    The dynamics of the photoevaporation of interstellar clouds and its consequences for the structure and evolution of H II regions are studied. An approximate analytical solution for the evolution of photoevaporating clouds is derived under the realistic assumption of axisymmetry. The effects of magnetic fields are taken into account in an approximate way. The evolution of a neutral cloud subjected to the ionizing radiation of an OB star has two distinct stages. When a cloud is first exposed to the radiation, the increase in pressure due to the ionization at the surface of the cloud leads to a radiation-driven implosion: an ionization front drives a shock into the cloud, ionizes part of it and compresses the remaining into a dense globule. The initial implosion is followed by an equilibrium cometary stage, in which the cloud maintains a semistationary comet-shaped configuration; it slowly evaporates while accelerating away from the ionizing star until the cloud has been completely ionized, reaches the edge of the H II region, or dies. Expressions are derived for the cloud mass-loss rate and acceleration. To investigate the effect of the cloud photoevaporation on the structure of H II regions, the evolution of an ensemble of clouds of a given mass distribution is studied. It is shown that the compressive effect of the ionizing radiation can induce star formation in clouds that were initially gravitationally stable, both for thermally and magnetically supported clouds

  12. Cloud Computing: A study of cloud architecture and its patterns

    OpenAIRE

    Mandeep Handa,; Shriya Sharma

    2015-01-01

    Cloud computing is a general term for anything that involves delivering hosted services over the Internet. Cloud computing is a paradigm shift following the shift from mainframe to client–server in the early 1980s. Cloud computing can be defined as accessing third party software and services on web and paying as per usage. It facilitates scalability and virtualized resources over Internet as a service providing cost effective and scalable solution to customers. Cloud computing has...

  13. Ash cloud aviation advisories

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, T.J.; Ellis, J.S. [Lawrence Livermore National Lab., CA (United States); Schalk, W.W.; Nasstrom, J.S. [EG and G, Inc., Pleasanton, CA (United States)

    1992-06-25

    During the recent (12--22 June 1991) Mount Pinatubo volcano eruptions, the US Air Force Global Weather Central (AFGWC) requested assistance of the US Department of Energy`s Atmospheric Release Advisory Capability (ARAC) in creating volcanic ash cloud aviation advisories for the region of the Philippine Islands. Through application of its three-dimensional material transport and diffusion models using AFGWC meteorological analysis and forecast wind fields ARAC developed extensive analysis and 12-hourly forecast ash cloud position advisories extending to 48 hours for a period of five days. The advisories consisted of ``relative`` ash cloud concentrations in ten layers (surface-5,000 feet, 5,000--10,000 feet and every 10,000 feet to 90,000 feet). The ash was represented as a log-normal size distribution of 10--200 {mu}m diameter solid particles. Size-dependent ``ashfall`` was simulated over time as the eruption clouds dispersed. Except for an internal experimental attempt to model one of the Mount Redoubt, Alaska, eruptions (12/89), ARAC had no prior experience in modeling volcanic eruption ash hazards. For the cataclysmic eruption of 15--16 June, the complex three-dimensional atmospheric structure of the region produced dramatically divergent ash cloud patterns. The large eruptions (> 7--10 km) produced ash plume clouds with strong westward transport over the South China Sea, Southeast Asia, India and beyond. The low-level eruptions (< 7 km) and quasi-steady-state venting produced a plume which generally dispersed to the north and east throughout the support period. Modeling the sequence of eruptions presented a unique challenge. Although the initial approach proved viable, further refinement is necessary and possible. A distinct need exists to quantify eruptions consistently such that ``relative`` ash concentrations relate to specific aviation hazard categories.

  14. Investigation into electron cloud effects in the International Linear Collider positron damping ring

    Energy Technology Data Exchange (ETDEWEB)

    Crittenden, J. A.; Conway, J.; Dugan, G. F.; Palmer, M. A.; Rubin, D. L.; Shanks, J.; Sonnad, K. G.; Boon, L.; Harkay, K.; Ishibashi, T.; Furman, M. A.; Guiducci, S.; Pivi, M. T. F.; Wang, L.

    2014-03-01

    We report modeling results for electron cloud buildup and instability in the International Linear Collider positron damping ring. Updated optics, wiggler magnets, and vacuum chamber designs have recently been developed for the 5 GeV, 3.2-km racetrack layout. An analysis of the synchrotron radiation profile around the ring has been performed, including the effects of diffuse and specular photon scattering on the interior surfaces of the vacuum chamber. The results provide input to the cloud buildup simulations for the various magnetic field regions of the ring. The modeled cloud densities thus obtained are used in the instability threshold calculations. We conclude that the mitigation techniques employed in this model will suffice to allow operation of the damping ring at the design operational specifications

  15. Cloud Collaboration: Cloud-Based Instruction for Business Writing Class

    Science.gov (United States)

    Lin, Charlie; Yu, Wei-Chieh Wayne; Wang, Jenny

    2014-01-01

    Cloud computing technologies, such as Google Docs, Adobe Creative Cloud, Dropbox, and Microsoft Windows Live, have become increasingly appreciated to the next generation digital learning tools. Cloud computing technologies encourage students' active engagement, collaboration, and participation in their learning, facilitate group work, and support…

  16. Cloud blueprints for integrating and managing cloud federations

    NARCIS (Netherlands)

    Papazoglou, M.; Heisel, M.

    2012-01-01

    Contemporary cloud technologies face insurmountable obstacles. They follow a pull-based, producer-centric trajectory to development where cloud consumers have to ‘squeeze and bolt’ applications onto cloud APIs. They also introduce a monolithic SaaS/PaaS/IaaS stack where a one-size-fits-all mentality

  17. Opaque cloud detection

    Science.gov (United States)

    Roskovensky, John K [Albuquerque, NM

    2009-01-20

    A method of detecting clouds in a digital image comprising, for an area of the digital image, determining a reflectance value in at least three discrete electromagnetic spectrum bands, computing a first ratio of one reflectance value minus another reflectance value and the same two values added together, computing a second ratio of one reflectance value and another reflectance value, choosing one of the reflectance values, and concluding that an opaque cloud exists in the area if the results of each of the two computing steps and the choosing step fall within three corresponding predetermined ranges.

  18. Storm and cloud dynamics

    CERN Document Server

    Cotton, William R

    1992-01-01

    This book focuses on the dynamics of clouds and of precipitating mesoscale meteorological systems. Clouds and precipitating mesoscale systems represent some of the most important and scientifically exciting weather systems in the world. These are the systems that produce torrential rains, severe winds including downburst and tornadoes, hail, thunder and lightning, and major snow storms. Forecasting such storms represents a major challenge since they are too small to be adequately resolved by conventional observing networks and numerical prediction models.Key Features* Key Highlight

  19. Detailed Information Security in Cloud Computing

    OpenAIRE

    Pavel Valerievich Ivonin

    2013-01-01

    The object of research in this article is technology of public clouds, structure and security system of clouds. Problems of information security in clouds are considered, elements of security system in public clouds are described.

  20. Cloud Based Applications and Platforms (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Brodt-Giles, D.

    2014-05-15

    Presentation to the Cloud Computing East 2014 Conference, where we are highlighting our cloud computing strategy, describing the platforms on the cloud (including Smartgrid.gov), and defining our process for implementing cloud based applications.

  1. Relationships among cloud occurrence frequency, overlap, and effective thickness derived from CALIPSO and CloudSat merged cloud vertical profiles

    Science.gov (United States)

    Kato, Seiji; Sun-Mack, Sunny; Miller, Walter F.; Rose, Fred G.; Chen, Yan; Minnis, Patrick; Wielicki, Bruce A.

    2010-01-01

    A cloud frequency of occurrence matrix is generated using merged cloud vertical profiles derived from the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and cloud profiling radar. The matrix contains vertical profiles of cloud occurrence frequency as a function of the uppermost cloud top. It is shown that the cloud fraction and uppermost cloud top vertical profiles can be related by a cloud overlap matrix when the correlation length of cloud occurrence, which is interpreted as an effective cloud thickness, is introduced. The underlying assumption in establishing the above relation is that cloud overlap approaches random overlap with increasing distance separating cloud layers and that the probability of deviating from random overlap decreases exponentially with distance. One month of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat data (July 2006) support these assumptions, although the correlation length sometimes increases with separation distance when the cloud top height is large. The data also show that the correlation length depends on cloud top hight and the maximum occurs when the cloud top height is 8 to 10 km. The cloud correlation length is equivalent to the decorrelation distance introduced by Hogan and Illingworth (2000) when cloud fractions of both layers in a two-cloud layer system are the same. The simple relationships derived in this study can be used to estimate the top-of-atmosphere irradiance difference caused by cloud fraction, uppermost cloud top, and cloud thickness vertical profile differences.

  2. A State-of-the-Art Experimental Laboratory for Cloud and Cloud-Aerosol Interaction Research

    Science.gov (United States)

    Fremaux, Charles M.; Bushnell, Dennis M.

    2011-01-01

    The state of the art for predicting climate changes due to increasing greenhouse gasses in the atmosphere with high accuracy is problematic. Confidence intervals on current long-term predictions (on the order of 100 years) are so large that the ability to make informed decisions with regard to optimum strategies for mitigating both the causes of climate change and its effects is in doubt. There is ample evidence in the literature that large sources of uncertainty in current climate models are various aerosol effects. One approach to furthering discovery as well as modeling, and verification and validation (V&V) for cloud-aerosol interactions is use of a large "cloud chamber" in a complimentary role to in-situ and remote sensing measurement approaches. Reproducing all of the complex interactions is not feasible, but it is suggested that the physics of certain key processes can be established in a laboratory setting so that relevant fluid-dynamic and cloud-aerosol phenomena can be experimentally simulated and studied in a controlled environment. This report presents a high-level argument for significantly improved laboratory capability, and is meant to serve as a starting point for stimulating discussion within the climate science and other interested communities.

  3. Securing virtual and cloud environments

    CSIR Research Space (South Africa)

    Carroll, M

    2012-01-01

    Full Text Available targets such as reduced costs, scalability, flexibility, capacity utilisation, higher efficiencies and mobility. Many of these benefits are achieved through the utilisation of technologies such as cloud computing and virtualisation. In many instances cloud...

  4. Efficient Resource Management in Cloud Computing

    OpenAIRE

    Rushikesh Shingade; Amit Patil; Shivam Suryawanshi; M. Venkatesan

    2015-01-01

    Cloud computing, one of the widely used technology to provide cloud services for users who are charged for receiving services. In the aspect of a maximum number of resources, evaluating the performance of Cloud resource management policies are difficult to optimize efficiently. There are different simulation toolkits available for simulation and modelling the Cloud computing environment like GridSim CloudAnalyst, CloudSim, GreenCloud, CloudAuction etc. In proposed Efficient Resource Manage...

  5. Cloud computing basics for librarians.

    Science.gov (United States)

    Hoy, Matthew B

    2012-01-01

    "Cloud computing" is the name for the recent trend of moving software and computing resources to an online, shared-service model. This article briefly defines cloud computing, discusses different models, explores the advantages and disadvantages, and describes some of the ways cloud computing can be used in libraries. Examples of cloud services are included at the end of the article. Copyright © Taylor & Francis Group, LLC

  6. Cloud Computing Security: A Survey

    OpenAIRE

    Khalil, Issa; Khreishah, Abdallah; Azeem, Muhammad

    2014-01-01

    Cloud computing is an emerging technology paradigm that migrates current technological and computing concepts into utility-like solutions similar to electricity and water systems. Clouds bring out a wide range of benefits including configurable computing resources, economic savings, and service flexibility. However, security and privacy concerns are shown to be the primary obstacles to a wide adoption of clouds. The new concepts that clouds introduce, such as multi-tenancy, resource sharing a...

  7. Database security in the cloud

    OpenAIRE

    Sakhi, Imal

    2012-01-01

    The aim of the thesis is to get an overview of the database services available in cloud computing environment, investigate the security risks associated with it and propose the possible countermeasures to minimize the risks. The thesis also analyzes two cloud database service providers namely; Amazon RDS and Xeround. The reason behind choosing these two providers is because they are currently amongst the leading cloud database providers and both provide relational cloud databases which makes ...

  8. QUALITY ASSURANCE FOR CLOUD COMPUTING

    OpenAIRE

    Sumaira Aslam; Hina Shahid

    2016-01-01

    Cloud computing is a greatest and latest thing. Marketers for lots of big companies are all using cloud computing terms in their marketing campaign to make them seem them impressive so, that they can get clients and customers. Cloud computing is overall the philosophy and design concept and it is much more complicated and yet much simpler. The basic underlined thing that cloud computing do is to separate the applications from operating systems from the software from the hardware that runs eve...

  9. Cloud services, networking, and management

    CERN Document Server

    da Fonseca, Nelson L S

    2015-01-01

    Cloud Services, Networking and Management provides a comprehensive overview of the cloud infrastructure and services, as well as their underlying management mechanisms, including data center virtualization and networking, cloud security and reliability, big data analytics, scientific and commercial applications. Special features of the book include: State-of-the-art content. Self-contained chapters for readers with specific interests. Includes commercial applications on Cloud (video services and games).

  10. Security Dynamics of Cloud Computing

    OpenAIRE

    Khan, Khaled M.

    2009-01-01

    This paper explores various dimensions of cloud computing security. It argues that security concerns of cloud computing need to be addressed from the perspective of individual stakeholder. Security focuses of cloud computing are essentially different in terms of its characteristics and business model. Conventional way of viewing as well as addressing security such as ‘bolting-in’ on the top of cloud computing may not work well. The paper attempts to portray the security spectrum necessary for...

  11. Green Cloud on the Horizon

    Science.gov (United States)

    Ali, Mufajjul

    This paper proposes a Green Cloud model for mobile Cloud computing. The proposed model leverage on the current trend of IaaS (Infrastructure as a Service), PaaS (Platform as a Service) and SaaS (Software as a Service), and look at new paradigm called "Network as a Service" (NaaS). The Green Cloud model proposes various Telco's revenue generating streams and services with the CaaS (Cloud as a Service) for the near future.

  12. Reusability Framework for Cloud Computing

    OpenAIRE

    Singh, Sukhpal; Singh, Rishideep

    2012-01-01

    Cloud based development is a challenging task for several software engineering projects, especially for those which needs development with reusability. Present time of cloud computing is allowing new professional models for using the software development. The expected upcoming trend of computing is assumed to be this cloud computing because of speed of application deployment, shorter time to market, and lower cost of operation. Until Cloud Co mputing Reusability Model is considered a fundamen...

  13. Comparison among different CT ionization chambers

    International Nuclear Information System (INIS)

    Castro, Maysa C. de; Xavier, Marcos; Caldas, Linda V.E.

    2015-01-01

    The dosimetry in computed tomography (CT) is carried out by the use of a pencil type ionization-chamber, because it has a uniform response at all angles relative to the incident beam of radiation, which is essential for CT equipment since the X-ray tube executes a circular movement around the table during irradiation. The commercial ionization chamber used to perform quality control procedures of this kind of equipment has a length of the sensitive volume of 10 cm. In the Calibration Laboratory of Instruments (LCI) of the IPEN there were already developed some prototypes with small differences in construction, when compared to commercially available ionization chambers. They have been used in previous studies and showed results within internationally acceptable limits. The ionization chambers tested in this study present the sensitive volume lengths of 1 cm, 3 cm and 10 cm. The objective of this study was to present results on the stability test of the three homemade ionization chambers and a commercial chamber, as well to obtain the calibration coefficients for each of them in CT standard X radiation beams. The obtained results for both characterization tests are within the recommended limits, except for the homemade ionization chambers with sensitive volume lengths of 3 cm and 1 cm in the case of the stability test. (author)

  14. Monitored Drift Chambers in the ATLAS Detector

    CERN Multimedia

    Herten, G

    Monitored Drift Chambers (MDT) are used in the ATLAS Detector to measure the momentum of high energy muons. They consist of drift tubes, which are filled with an Ar-CO2 gas mixture at 3 bar gas pressure. About 1200 drift chambers are required for ATLAS. They are up to 6 m long. Nevertheless the position of every wire needs to be known with a precision of 20 µm within a chamber. In addition, optical alignment sensors are required to measure the relative position of adjacent chambers with a precision of 30µm. This gigantic task seems impossible at first instance. Indeed it took many years of R&D to invent the right tools and methods before the first chamber could be built according to specifications. Today, at the time when 50% of the chambers have been produced, we are confident that the goal for ATLAS can be reached. The mechanical precision of the chambers could be verified with the x-ray tomograph at CERN. This ingenious device, developed for the MDT system, is able to measure the wire position insid...

  15. Making MUSIC: A multiple sampling ionization chamber

    International Nuclear Information System (INIS)

    Shumard, B.; Henderson, D.J.; Rehm, K.E.; Tang, X.D.

    2007-01-01

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the (α, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for (α, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only (α, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. x 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the (α, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the (α, p) reaction to reach the anode segment below the reaction

  16. Making MUSIC: A multiple sampling ionization chamber

    Science.gov (United States)

    Shumard, B.; Henderson, D. J.; Rehm, K. E.; Tang, X. D.

    2007-08-01

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the (α, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for (α, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only (α, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. × 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the (α, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the (α, p) reaction to reach the anode segment below the reaction.

  17. Making MUSIC: A multiple sampling ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Shumard, B. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)]. E-mail: shumard@phy.anl.gov; Henderson, D.J. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Rehm, K.E. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Tang, X.D. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)

    2007-08-15

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the ({alpha}, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for ({alpha}, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only ({alpha}, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. x 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the ({alpha}, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the ({alpha}, p) reaction to reach the anode segment below the reaction.

  18. iCloud standard guide

    CERN Document Server

    Alfi, Fauzan

    2013-01-01

    An easy-to-use guide, filled with tutorials that will teach you how to set up and use iCloud, and profit from all of its marvellous features.This book is for anyone with basic knowledge of computers and mobile operations. Prior knowledge of cloud computing or iCloud is not expected.

  19. Coherent Radiation of Electron Cloud

    International Nuclear Information System (INIS)

    Heifets, S.

    2004-01-01

    The electron cloud in positron storage rings is pinched when a bunch passes by. For short bunches, the radiation due to acceleration of electrons of the cloud is coherent. Detection of such radiation can be used to measure the density of the cloud. The estimate of the power and the time structure of the radiated signal is given in this paper

  20. Understanding and Monitoring Cloud Services

    NARCIS (Netherlands)

    Drago, Idilio

    2013-01-01

    Cloud services have changed the way computing power is delivered to customers. The advantages of the cloud model have fast resulted in powerful providers. However, this success has not come without problems. Cloud providers have been related to major failures, including outages and performance

  1. Research on cloud computing solutions

    Directory of Open Access Journals (Sweden)

    Liudvikas Kaklauskas

    2015-07-01

    Full Text Available Cloud computing can be defined as a new style of computing in which dynamically scala-ble and often virtualized resources are provided as a services over the Internet. Advantages of the cloud computing technology include cost savings, high availability, and easy scalability. Voas and Zhang adapted six phases of computing paradigms, from dummy termi-nals/mainframes, to PCs, networking computing, to grid and cloud computing. There are four types of cloud computing: public cloud, private cloud, hybrid cloud and community. The most common and well-known deployment model is Public Cloud. A Private Cloud is suited for sensitive data, where the customer is dependent on a certain degree of security.According to the different types of services offered, cloud computing can be considered to consist of three layers (services models: IaaS (infrastructure as a service, PaaS (platform as a service, SaaS (software as a service. Main cloud computing solutions: web applications, data hosting, virtualization, database clusters and terminal services. The advantage of cloud com-puting is the ability to virtualize and share resources among different applications with the objective for better server utilization and without a clustering solution, a service may fail at the moment the server crashes.DOI: 10.15181/csat.v2i2.914

  2. GEWEX cloud assessment: A review

    Science.gov (United States)

    Stubenrauch, Claudia; Rossow, William B.; Kinne, Stefan; Ackerman, Steve; Cesana, Gregory; Chepfer, Hélène; Di Girolamo, Larry; Getzewich, Brian; Guignard, Anthony; Heidinger, Andy; Maddux, Brent; Menzel, Paul; Minnis, Patrick; Pearl, Cindy; Platnick, Steven; Poulsen, Caroline; Riedi, Jérôme; Sayer, Andrew; Sun-Mack, Sunny; Walther, Andi; Winker, Dave; Zeng, Shen; Zhao, Guangyu

    2013-05-01

    Clouds cover about 70% of the Earth's surface and play a dominant role in the energy and water cycle of our planet. Only satellite observations provide a continuous survey of the state of the atmosphere over the entire globe and across the wide range of spatial and temporal scales that comprise weather and climate variability. Satellite cloud data records now exceed more than 25 years; however, climatologies compiled from different satellite datasets can exhibit systematic biases. Questions therefore arise as to the accuracy and limitations of the various sensors. The Global Energy and Water cycle Experiment (GEWEX) Cloud Assessment, initiated in 2005 by the GEWEX Radiation Panel, provides the first coordinated intercomparison of publicly available, global cloud products (gridded, monthly statistics) retrieved from measurements of multi-spectral imagers (some with multi-angle view and polarization capabilities), IR sounders and lidar. Cloud properties under study include cloud amount, cloud height (in terms of pressure, temperature or altitude), cloud radiative properties (optical depth or emissivity), cloud thermodynamic phase and bulk microphysical properties (effective particle size and water path). Differences in average cloud properties, especially in the amount of high-level clouds, are mostly explained by the inherent instrument measurement capability for detecting and/or identifying optically thin cirrus, especially when overlying low-level clouds. The study of long-term variations with these datasets requires consideration of many factors. The monthly, gridded database presented here facilitates further assessments, climate studies, and the evaluation of climate models.

  3. The Basics of Cloud Computing

    Science.gov (United States)

    Kaestner, Rich

    2012-01-01

    Most school business officials have heard the term "cloud computing" bandied about and may have some idea of what the term means. In fact, they likely already leverage a cloud-computing solution somewhere within their district. But what does cloud computing really mean? This brief article puts a bit of definition behind the term and helps one…

  4. Towards trustworthy health platform cloud

    NARCIS (Netherlands)

    Deng, M.; Nalin, M.; Petkovic, M.; Baroni, I.; Marco, A.; Jonker, W.; Petkovic, M.

    2012-01-01

    To address today’s major concerns of health service providers regarding security, resilience and data protection when moving on the cloud, we propose an approach to build a trustworthy healthcare platform cloud, based on a trustworthy cloud infrastructure. This paper first highlights the main

  5. A View from the Clouds

    Science.gov (United States)

    Chudnov, Daniel

    2010-01-01

    Cloud computing is definitely a thing now, but it's not new and it's not even novel. Back when people were first learning about the Internet in the 1990s, every diagram that one saw showing how the Internet worked had a big cloud in the middle. That cloud represented the diverse links, routers, gateways, and protocols that passed traffic around in…

  6. Trusting Privacy in the Cloud

    NARCIS (Netherlands)

    Prüfer, J.O.

    2014-01-01

    Cloud computing technologies have the potential to increase innovation and economic growth considerably. But many users worry that data in the cloud can be accessed by others, thereby damaging the data owner. Consequently, they do not use cloud technologies up to the efficient level. I design an

  7. Securing the Cloud Cloud Computer Security Techniques and Tactics

    CERN Document Server

    Winkler, Vic (JR)

    2011-01-01

    As companies turn to cloud computing technology to streamline and save money, security is a fundamental concern. Loss of certain control and lack of trust make this transition difficult unless you know how to handle it. Securing the Cloud discusses making the move to the cloud while securing your peice of it! The cloud offers felxibility, adaptability, scalability, and in the case of security-resilience. This book details the strengths and weaknesses of securing your company's information with different cloud approaches. Attacks can focus on your infrastructure, communications network, data, o

  8. AceCloud: Molecular Dynamics Simulations in the Cloud.

    Science.gov (United States)

    Harvey, M J; De Fabritiis, G

    2015-05-26

    We present AceCloud, an on-demand service for molecular dynamics simulations. AceCloud is designed to facilitate the secure execution of large ensembles of simulations on an external cloud computing service (currently Amazon Web Services). The AceCloud client, integrated into the ACEMD molecular dynamics package, provides an easy-to-use interface that abstracts all aspects of interaction with the cloud services. This gives the user the experience that all simulations are running on their local machine, minimizing the learning curve typically associated with the transition to using high performance computing services.

  9. VMware private cloud computing with vCloud director

    CERN Document Server

    Gallagher, Simon

    2013-01-01

    It's All About Delivering Service with vCloud Director Empowered by virtualization, companies are not just moving into the cloud, they're moving into private clouds for greater security, flexibility, and cost savings. However, this move involves more than just infrastructure. It also represents a different business model and a new way to provide services. In this detailed book, VMware vExpert Simon Gallagher makes sense of private cloud computing for IT administrators. From basic cloud theory and strategies for adoption to practical implementation, he covers all the issues. You'll lea

  10. LEP vacuum chamber, cross-section

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Cross-section of the final prototype for the LEP vacuum chamber. The elliptic main-opening is for the beam. The small channel to the left is for the cooling water, to carry away the heat deposited by the synchrotron radiation. The square channel to the right houses the Non-Evaporable Getter (NEG) pump. The chamber is made from extruded aluminium. Its outside is clad with lead, to stop the synchrotron radiation emitted by the beam. For good adherence between Pb and Al, the Al chamber was coated with a thin layer of Ni. Ni being slightly magnetic, some resulting problems had to be overcome. See also 8301153.

  11. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

    This image is of real particle tracks taken from the CERN 2 m liquid hydrogen bubble chamber and shows the production and decay of a negative omega particle. A negative kaon enters the chamber which decays into many particles, including a negative omega that travels a short distance before decaying into more particles. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  12. Growing and Analyzing Biofilms in Flow Chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber–grown biofilms are addressed. Curr. Protoc. Microbiol. 21:1B.2.1-1B.2.17. © 2011 by John Wiley & Sons, Inc....

  13. Dilution refrigeration with multiple mixing chambers

    International Nuclear Information System (INIS)

    Coops, G.M.

    1981-01-01

    A dilution refrigerator is an instrument to reach temperatures in the mK region in a continuous way. The temperature range can be extended and the cooling power can be enlarged by adding an extra mixing chamber. In this way we obtain a double mixing chamber system. In this thesis the theory of the multiple mixing chamber is presented and tested on its validity by comparison with the measurements. Measurements on a dilution refrigerator with a circulation rate up to 2.5 mmol/s are also reported. (Auth.)

  14. Weld Development for Aluminum Fission Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Cross, Carl Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Jesse Norris [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-16

    The Sigma welding team was approached to help fabricate a small fission chamber (roughly ½ inch dia. x ½ inch tall cylinder). These chambers are used as radiation sensors that contain small traces of radionuclides (Cf 252, U 235, and U 238) that serve to ionize gas atoms in addition to external radiation. When a voltage is applied within the chamber, the resulting ion flow can be calibrated and monitored. Aluminum has the advantage of not forming radioactive compounds when exposed to high external radiation (except from minor Na alloy content). Since aluminum has not been used before in this application, this presented an unexplored challenge.

  15. Benchmarking personal cloud storage

    NARCIS (Netherlands)

    Drago, Idilio; Bocchi, Enrico; Mellia, Marco; Slatman, Herman; Pras, Aiko

    2013-01-01

    Personal cloud storage services are data-intensive applications already producing a significant share of Internet traffic. Several solutions offered by different companies attract more and more people. However, little is known about each service capabilities, architecture and - most of all -

  16. CLOUD COMPUTING SECURITY ISSUES

    Directory of Open Access Journals (Sweden)

    Florin OGIGAU-NEAMTIU

    2012-01-01

    Full Text Available The term “cloud computing” has been in the spotlights of IT specialists the last years because of its potential to transform this industry. The promised benefits have determined companies to invest great sums of money in researching and developing this domain and great steps have been made towards implementing this technology. Managers have traditionally viewed IT as difficult and expensive and the promise of cloud computing leads many to think that IT will now be easy and cheap. The reality is that cloud computing has simplified some technical aspects of building computer systems, but the myriad challenges facing IT environment still remain. Organizations which consider adopting cloud based services must also understand the many major problems of information policy, including issues of privacy, security, reliability, access, and regulation. The goal of this article is to identify the main security issues and to draw the attention of both decision makers and users to the potential risks of moving data into “the cloud”.

  17. Computing in the Clouds

    Science.gov (United States)

    Johnson, Doug

    2010-01-01

    Web-based applications offer teachers, students, and school districts a convenient way to accomplish a wide range of tasks, from accounting to word processing, for free. Cloud computing has the potential to offer staff and students better services at a lower cost than the technology deployment models they're using now. Saving money and improving…

  18. CloudETL

    DEFF Research Database (Denmark)

    Liu, Xiufeng; Thomsen, Christian; Pedersen, Torben Bach

    2014-01-01

    Extract-Transform-Load (ETL) programs process data into data warehouses (DWs). Rapidly growing data volumes demand systems that scale out. Recently, much attention has been given to MapReduce for parallel handling of massive data sets in cloud environments. Hive is the most widely used RDBMS...

  19. Predictable cloud computing

    NARCIS (Netherlands)

    Mullender, Sape J.

    The standard tools for cloud computing—processor and network virtualization—make it difficult to achieve dependability, both in terms of real time operations and fault tolerance. Virtualization multiplexes virtual resources onto physical ones, typically by time division or statistical multiplexing.

  20. SiCloud

    DEFF Research Database (Denmark)

    Jiang, Cathy Y.; Devore, Peter T.S.; Lonappan, Cejo Konuparamban

    2017-01-01

    The silicon photonics industry is projected to be a multibillion dollar industry driven by the growth of data centers. In this work, we present an interactive online tool for silicon photonics. Silicon Photonics Cloud (SiCCloud.org) is an easy to use instructional tool for optical properties...

  1. Towards autonomous vehicular clouds

    Directory of Open Access Journals (Sweden)

    Stephan Olariu

    2011-09-01

    Full Text Available The dawn of the 21st century has seen a growing interest in vehicular networking and its myriad potential applications. The initial view of practitioners and researchers was that radio-equipped vehicles could keep the drivers informed about potential safety risks and increase their awareness of road conditions. The view then expanded to include access to the Internet and associated services. This position paper proposes and promotes a novel and more comprehensive vision namely, that advances in vehicular networks, embedded devices and cloud computing will enable the formation of autonomous clouds of vehicular computing, communication, sensing, power and physical resources. Hence, we coin the term, autonomous vehicular clouds (AVCs. A key feature distinguishing AVCs from conventional cloud computing is that mobile AVC resources can be pooled dynamically to serve authorized users and to enable autonomy in real-time service sharing and management on terrestrial, aerial, or aquatic pathways or theaters of operations. In addition to general-purpose AVCs, we also envision the emergence of specialized AVCs such as mobile analytics laboratories. Furthermore, we envision that the integration of AVCs with ubiquitous smart infrastructures including intelligent transportation systems, smart cities and smart electric power grids will have an enormous societal impact enabling ubiquitous utility cyber-physical services at the right place, right time and with right-sized resources.

  2. Seeding the Cloud

    Science.gov (United States)

    Schaffhauser, Dian

    2013-01-01

    For any institution looking to shift enterprise resource planning (ERP) systems to the cloud, big savings can be achieved--but only if the school has properly prepped "before" negotiations begin. These three steps can help: (1) Mop up the mess first; (2) Understand the true costs for services; and (3) Calculate the cost of transition.

  3. Data in the Cloud

    Science.gov (United States)

    Bull, Glen; Garofalo, Joe

    2010-01-01

    The ability to move from one representation of data to another is one of the key characteristics of expert mathematicians and scientists. Cloud computing will offer more opportunities to create and display multiple representations of data, making this skill even more important in the future. The advent of the Internet led to widespread…

  4. New Electron Cloud Detectors for the PS Main Magnets

    CERN Document Server

    Yin Vallgren, Ch; Gilardoni, S; Taborelli, M; Neupert, H; Ferreira Somoza, J

    2014-01-01

    Electron cloud (EC) has already been observed during normal operation of the PS, therefore it is necessary to study its in fluence on any beam instability for the future LHC Injector Upgrade (LIU). Two new electron cloud detectors have been discussed, developed and installed during the Long Shutdown (LS1) in one of the PS main magnets. The first measurement method is based on current measurement by using a shielded button-type pick-up. Due to the geometry and space limitation in the PS magnet, the button-type pick-up made of a 96%Al2O3 block coated with a thin layer of solvent-based Ag painting, placed 30 degrees to the bottom part of the vacuum chamber was installed in the horizontal direction where the only opening of the magnet coil is. The other newly developed measurement method is based on detection of photons emitted by the electrons from the electron cloud impinging on the vacuum chamber walls. The emitted photons are reected to a quartz window. A MCP-PMT (Micro-Channel Plate Photomultiplier Tube) wit...

  5. AIRS-CloudSat cloud mask, radar reflectivities, and cloud classification matchups V3.2

    Data.gov (United States)

    National Aeronautics and Space Administration — This is AIRS-CloudSat collocated subset, in NetCDF 4 format. These data contain collocated: AIRS Level 1b radiances spectra, CloudSat radar reflectivities, and MODIS...

  6. Relating pressure measurements to phenomena observed in high speed video recordings during tests of explosive charges in a semi-confined blast chamber

    CSIR Research Space (South Africa)

    Mostert, FJ

    2012-09-01

    Full Text Available initiation of the charge. It was observed in the video recordings that the detonation product cloud exhibited pulsating behaviour due to the reflected shocks in the chamber analogous to the behaviour of the gas bubble in underwater explosions. This behaviour...

  7. Arsia Mons Spiral Cloud

    Science.gov (United States)

    2002-01-01

    One of the benefits of the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Extended Mission is the opportunity to observe how the planet's weather changes during a second full martian year. This picture of Arsia Mons was taken June 19, 2001; southern spring equinox occurred the same day. Arsia Mons is a volcano nearly large enough to cover the state of New Mexico. On this particular day (the first day of Spring), the MOC wide angle cameras documented an unusual spiral-shaped cloud within the 110 km (68 mi) diameter caldera--the summit crater--of the giant volcano. Because the cloud is bright both in the red and blue images acquired by the wide angle cameras, it probably consisted mostly of fine dust grains. The cloud's spin may have been induced by winds off the inner slopes of the volcano's caldera walls resulting from the temperature differences between the walls and the caldera floor, or by a vortex as winds blew up and over the caldera. Similar spiral clouds were seen inside the caldera for several days; we don't know if this was a single cloud that persisted throughout that time or one that regenerated each afternoon. Sunlight illuminates this scene from the left/upper left.Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  8. A comparison of shock-cloud and wind-cloud interactions: effect of increased cloud density contrast on cloud evolution

    Science.gov (United States)

    Goldsmith, K. J. A.; Pittard, J. M.

    2018-05-01

    The similarities, or otherwise, of a shock or wind interacting with a cloud of density contrast χ = 10 were explored in a previous paper. Here, we investigate such interactions with clouds of higher density contrast. We compare the adiabatic hydrodynamic interaction of a Mach 10 shock with a spherical cloud of χ = 103 with that of a cloud embedded in a wind with identical parameters to the post-shock flow. We find that initially there are only minor morphological differences between the shock-cloud and wind-cloud interactions, compared to when χ = 10. However, once the transmitted shock exits the cloud, the development of a turbulent wake and fragmentation of the cloud differs between the two simulations. On increasing the wind Mach number, we note the development of a thin, smooth tail of cloud material, which is then disrupted by the fragmentation of the cloud core and subsequent `mass-loading' of the flow. We find that the normalized cloud mixing time (tmix) is shorter at higher χ. However, a strong Mach number dependence on tmix and the normalized cloud drag time, t_{drag}^' }, is not observed. Mach-number-dependent values of tmix and t_{drag}^' } from comparable shock-cloud interactions converge towards the Mach-number-independent time-scales of the wind-cloud simulations. We find that high χ clouds can be accelerated up to 80-90 per cent of the wind velocity and travel large distances before being significantly mixed. However, complete mixing is not achieved in our simulations and at late times the flow remains perturbed.

  9. Organic Aerosols as Cloud Condensation Nuclei

    Science.gov (United States)

    Hudson, J. G.

    2002-05-01

    agreement between these cloud chambers then tests and defines the limits of possible alterations of conventional Kohler theory (e.g., Kulmala et al. 1993).

  10. Cloud Computing Security Issue: Survey

    Science.gov (United States)

    Kamal, Shailza; Kaur, Rajpreet

    2011-12-01

    Cloud computing is the growing field in IT industry since 2007 proposed by IBM. Another company like Google, Amazon, and Microsoft provides further products to cloud computing. The cloud computing is the internet based computing that shared recourses, information on demand. It provides the services like SaaS, IaaS and PaaS. The services and recourses are shared by virtualization that run multiple operation applications on cloud computing. This discussion gives the survey on the challenges on security issues during cloud computing and describes some standards and protocols that presents how security can be managed.

  11. Security for cloud storage systems

    CERN Document Server

    Yang, Kan

    2014-01-01

    Cloud storage is an important service of cloud computing, which offers service for data owners to host their data in the cloud. This new paradigm of data hosting and data access services introduces two major security concerns. The first is the protection of data integrity. Data owners may not fully trust the cloud server and worry that data stored in the cloud could be corrupted or even removed. The second is data access control. Data owners may worry that some dishonest servers provide data access to users that are not permitted for profit gain and thus they can no longer rely on the servers

  12. Cloud database development and management

    CERN Document Server

    Chao, Lee

    2013-01-01

    Nowadays, cloud computing is almost everywhere. However, one can hardly find a textbook that utilizes cloud computing for teaching database and application development. This cloud-based database development book teaches both the theory and practice with step-by-step instructions and examples. This book helps readers to set up a cloud computing environment for teaching and learning database systems. The book will cover adequate conceptual content for students and IT professionals to gain necessary knowledge and hands-on skills to set up cloud based database systems.

  13. Irradiation chamber for photoactivation patient treatment system

    International Nuclear Information System (INIS)

    Lee, K.H.; Troutner, V.H.; Goss, J.; King, M.J.

    1988-01-01

    A flat plate irradiation chamber is described for use in a patient treatment system for altering cells, including treating the cells with a photoactivatable agent and passing the cells and the agent through a field of photoactivating radiation whereby the agent is caused to be activated and to affect the cells. The agent and the cells are contained in the irradiation chamber during irradiation. The flat plate irradiation chamber comprises: a rigid top sheet matably joined with a rigid bottom sheet, forming therebetween a rigid serpentine pathway for conducting the cells through the field of radiation; and pump block means for holding tubing means in fluid communication with the serpentine pathway and adapted for engaging a peristaltic pump whereby rotation of the pump causes the cells to flow through the serpentine pathway, and wherein the chamber is removable from the system and disposable

  14. A liquid ionization chamber using tetramethylsilane

    International Nuclear Information System (INIS)

    Engler, J.; Keim, H.

    1983-12-01

    First results with a liquid ionization chamber using tetramethylsilane (TMS) are presented. A stack of iron plates was tested with cosmic ray muons and the charge output for minimum ionizing particles was measured. (orig.) [de

  15. Uranium deposits obtention for fission chambers

    International Nuclear Information System (INIS)

    Artacho Saviron, E.

    1972-01-01

    The obtention of uranium deposits of the required quality for small cylindrical fission chambers presents some difficulties. With the method of electroplating here described the uniformity, reproducibility and adherence of the obtained deposits were satisfactory. (Author) 6 refs

  16. RADAR Anechoic Chamber/RCS Measurements Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The RF Anechoic Chamber is 56 feet long by 12 feet high by 13.5 feet wide, with an adjoining electronic computer control room. A double door entrance at one end of...

  17. MAN-IN-SIMULANT TEST (MIST) CHAMBER

    Data.gov (United States)

    Federal Laboratory Consortium — The MIST chamber uses methyl salicylate (oil of wintergreen) vapor as a simulant for HD agent to conduct system level evaluations of chemical protective ensembles....

  18. HYLIFE-II reactor chamber design refinements

    International Nuclear Information System (INIS)

    House, P.A.

    1994-06-01

    Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li 2 BeF 4 ) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (>12 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GWe and 2 GWe reactor chamber are presented

  19. Equipment upgrade - Accurate positioning of ion chambers

    International Nuclear Information System (INIS)

    Doane, Harry J.; Nelson, George W.

    1990-01-01

    Five adjustable clamps were made to firmly support and accurately position the ion Chambers, that provide signals to the power channels for the University of Arizona TRIGA reactor. The design requirements, fabrication procedure and installation are described

  20. Chamber Core Structures for Fairing Acoustic Mitigation

    National Research Council Canada - National Science Library

    Lane, Steven A; Henderson, Kyle; Williams, Andrew; Ardelean, Emil

    2007-01-01

    .... A composite chamber core fairing consists of many axial tubes sandwiched between face sheets, tubes that can be used as acoustic dampers to reduce low-frequency interior noise with virtually no added mass...

  1. Accelerated Solar-UV Test Chamber

    Science.gov (United States)

    Gupta, A.; Laue, E. G.

    1984-01-01

    Medium-pressure mercury-vapor lamps provide high ratio of ultraviolet to total power. Chamber for evaluating solar-ultraviolet (UV) radiation damage permits accelerated testing without overheating test specimens.

  2. Very high intensity reaction chamber design

    International Nuclear Information System (INIS)

    Devaney, J.J.

    1975-09-01

    The problem of achieving very high intensity irradiation by light in minimal regions was studied. Three types of irradiation chamber are suggested: the common laser-reaction chamber, the folded concentric or near-concentric resonator, and the asymmetric confocal resonator. In all designs the ratio of high-intensity illuminated volume to other volume is highly dependent (to the 3 / 2 power) on the power and fluence tolerances of optical elements, primarily mirrors. Optimization of energy coupling is discussed for the common cavity. For the concentric cavities, optimization for both coherent and incoherent beams is treated. Formulae and numerical examples give the size of chambers, aspect ratios, maximum pass number, image sizes, fluences, and the like. Similarly for the asymmetric confocal chamber, formulae and numerical examples for fluences, dimensions, losses, and totally contained pass numbers are given

  3. Liquid ionization chambers for LET determination

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki

    Liquid ionization chambers [1] (LICs) have have been used in the last decades as background dosemeters. Since a few years LICs are also commercially available for dosimetry and are used for measurements of dose distributions where a high spatial distribution is necessary. Also in the last decades...... a differential equation applying several simplifications and approximations leading to discrepancies between theory and experiments [3]. The theory predicts the collection efficiency as a function of the electrical field and was applied for both air filled ionization chambers and liquid filled ionization...... chambers. For liquids the LET can be roughly deduced from the collection efficiency dependency on the electrical field inside a liquid ionization chambers [4] using an extrapolation method. We solved the fundamental differential equation again presented by Jaffe numerically, but now taking into account...

  4. Ultrasonic cleaning of electrodes of wire chambers

    International Nuclear Information System (INIS)

    Krasnov, V.A.; Kurepin, A.B.; Razin, V.I.

    1980-01-01

    A technological process of cleaning electrodes and working volume surfaces of wire chambers from contaminations by the simultaneous mechanical action of the energy of ultrasonic oscillations and the chemical action of detergents is discussed. A device for cleaning wire electrodes of proportional chambers of 0.3x0.4 m is described. The device uses two ultrasonic generators with a total power of 0.5 kW. As a detergent use is made of a mixture of ethyl alcohol, gasoline and freon. In the process of cleaning production defects can be detected in the wire chambers which makes it possible to timely remove the defects. Measurements of the surface resistance of fiberglass laminate of printed drift chamber electrodes at a voltage of 2 kV showed that after completing the cleaning process the resistance increases 15-20%

  5. Formation of giant molecular clouds in global spiral structures: the role of orbital dynamics and cloud-cloud collisions

    International Nuclear Information System (INIS)

    Roberts, W.W. Jr.; Stewart, G.R.

    1987-01-01

    The different roles played by orbital dynamics and dissipative cloud-cloud collisions in the formation of giant molecular clouds (GMCs) in a global spiral structure are investigated. The interstellar medium (ISM) is simulated by a system of particles, representing clouds, which orbit in a spiral-perturbed, galactic gravitational field. The overall magnitude and width of the global cloud density distribution in spiral arms is very similar in the collisional and collisionless simulations. The results suggest that the assumed number density and size distribution of clouds and the details of individual cloud-cloud collisions have relatively little effect on these features. Dissipative cloud-cloud collisions play an important steadying role for the cloud system's global spiral structure. Dissipative cloud-cloud collisions also damp the relative velocity dispersion of clouds in massive associations and thereby aid in the effective assembling of GMC-like complexes

  6. Radon progeny distribution in cylindrical diffusion chambers

    International Nuclear Information System (INIS)

    Pressyanov, Dobromir S.

    2008-01-01

    An algorithm to model the diffusion of radioactive decay chain atoms is presented. Exact mathematical solutions in cylindrical geometry are given. They are used to obtain expressions for the concentrations of 222 Rn progeny atoms in the volume and deposited on the wall surface in cylindrical diffusion chambers. The dependence of volume fractions of 222 Rn progeny and chamber sensitivity on the coefficient of diffusion of 222 Rn progeny atoms in air is modeled.

  7. The large cylindrical drift chamber of TASSO

    International Nuclear Information System (INIS)

    Boerner, H.; Fischer, H.M.; Hartmann, H.; Loehr, B.; Wollstadt, M.; Fohrmann, R.; Schmueser, P.; Cassel, D.G.; Koetz, U.; Kowalski, H.

    1980-03-01

    We have built and operated a large cylindrical drift chamber for the TASSO experiment at the DESY storage ring, PETRA. The chamber has a length of 3.5 m, a diameter of 2.5 m, and a total of 2340 drift cells. The cells are arranged in 15 concentric layers such that tracks can be reconstructed in three dimensions. A spatial resolution of 220 μm has been achieved for tracks of normal incidence on the drift cells. (orig.)

  8. Cylindrical geometry for proportional and drift chambers

    International Nuclear Information System (INIS)

    Sadoulet, B.

    1975-06-01

    For experiments performed around storage rings such as e + e - rings or the ISR pp rings, cylindrical wire chambers are very attractive. They surround the beam pipe completely without any dead region in the azimuth, and fit well with the geometry of events where particles are more or less spherically produced. Unfortunately, cylindrical proportional or drift chambers are difficult to make. Problems are discussed and two approaches to fabricating the cathodes are discussed. (WHK)

  9. Tracking with wire chambers at the SSC

    International Nuclear Information System (INIS)

    Hanson, G.G.; Gundy, M.C.; Palounek, A.P.T.

    1989-07-01

    Limitations placed on wire chambers by radiation damage and rate requirements in the SSC environment are reviewed. Possible conceptual designs for wire chamber tacking systems that meet these requirements are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given. 13 refs., 11 fig., 1 tab

  10. Characteristic parameters of drift chambers calculation

    International Nuclear Information System (INIS)

    Duran, I.; Martinez-Laso, L.

    1989-01-01

    We present here the methods we used to analyse the characteristic parameters of drift chambers. The algorithms to calculate the electric potential in any point for any drift chamber geometry are presented. We include the description of the programs used to calculate the electric field, the drift paths, the drift velocity and the drift time. The results and the errors are discussed. (Author) 7 refs

  11. OPAL jet chamber full scale prototype

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, H M; Hauschild, M; Hartmann, H; Hegerath, A; Boerner, H; Burckhart, H J; Dittmar, M; Hammarstroem, R; Heuer, R D; Mazzone, L

    1986-12-01

    The concept of a jet chamber for the central detector of OPAL has been tested with a full scale prototype. The design of this prototype, its mechanical and electrical structure and its support system for high voltage, gas, laser calibration and readout are described. Operating experience has been gathered since summer 1984. The chamber performance in terms of spatial resolution and particle identification capability is given.

  12. OPAL jet chamber full scale prototype

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, H M; Hauschild, M; Hartmann, H; Hegerath, A; Boerner, H; Burckhart, H J; Dittmar, M; Hammarstreom, R; Heuer, R D; Mazzone, L

    1986-05-22

    The concept of a jet chamber for the central detector of OPAL has been tested with a full scale prototype. The design of this prototype, its mechanical and electrical structure and its support system for high voltage, gas, laser calibration and readout are described. The operating experience gathered since the summer of 1984 and the chamber performance as measured by its spatial resolution and ability to identify particles are also given.

  13. Georges Charpak and his multiwire chamber

    CERN Multimedia

    1970-01-01

    In 1968, Georges Charpak developed the 'multiwire proportional chamber', a gas-filled box with a large number of parallel detector wires, each connected to individual amplifiers. Linked to a computer, it could achieve a counting rate a thousand times better than existing techniques - without a camera in sight. From left to right, Georges Charpak, Fabio Sauli and Jean-Claude Santiard working on a multiwire chamber in 1970.

  14. Holographic processing of track chamber data

    Energy Technology Data Exchange (ETDEWEB)

    Bykovsky, Y A; Larkin, A I; Markilov, A A; Starikov, S N [Moskovskij Fiziko-Tekhnicheskij Inst. (USSR)

    1975-12-01

    The holographic pattern recognition method was applied for processing of track chamber photographs. Experiments on detection of such events as a definitely directed track, an angle formed by two tracks, a three-pronged star, a definitely curved track were performed by using models. It is proposed to recognize these events in a filmshot by the shape of correlation signals. The experiment to recognize the event in a real bubble chamber filmshot was realized; requirements to the processing films were determined.

  15. A very large multigap resistive plate chamber

    CERN Document Server

    Cerron-Zeballos, E; Hatzifotiadou, D; Kim, D W; Lamas-Valverde, J; Lee, S C; Platner, E D; Roberts, J; Williams, M C S; Zichichi, A

    1999-01-01

    We have built and tested a very large multigap resistive plate chamber (MRPC). We discuss the suitability of the multigap RPC for the construction of large area modules. We give details of the construction technique and results from a scan across the surface of the chamber. We also report on the implementation of `half-strip resolution', where we improve the spatial resolution by a factor 2 without increasing the number of read-out channels. (9 refs).

  16. Vertex chamber for the KEDR detector

    International Nuclear Information System (INIS)

    Aulchenko, V.M.; Chilingarov, A.G.; Kolachev, G.M.; Lazarenko, O.B.; Nagaslaev, V.P.; Romanov, L.V.

    1989-01-01

    The project and design of the vertex chamber for the KEDR detector is described. The chamber consists of 6 cylindrical layers of tubes with 10 mm diameter and 800 mm length. The tubes are made of 20 μm thick aluminized mylar. The prototype tests show that it is possible to achieve a resolution of 20-30 μm using the cool gas mixtures. (orig.)

  17. Tracking with wire chambers at high luminosities

    International Nuclear Information System (INIS)

    Hanson, G.G.

    1989-12-01

    Radiation damage and rate limitations impose severe constraints on wire chambers at the SSC. Possible conceptual designs for wire chamber tracking systems that satisfy these constraints are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given. 11 refs., 10 figs

  18. Atmospheric diffusion of large clouds

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, T. V. [Univ. of California, Lawrence Radiation Lab., Livermore, California (United States)

    1967-07-01

    Clouds of pollutants travel within a coordinate system that is fixed to the earth's surface, and they diffuse and grow within a coordinate system fixed to the cloud's center. This paper discusses an approach to predicting the cloud's properties, within the latter coordinate system, on space scales of a few hundred meters to a few hundred kilometers and for time periods of a few days. A numerical cloud diffusion model is presented which starts with a cloud placed arbitrarily within the troposphere. Similarity theories of atmospheric turbulence are used to predict the horizontal diffusivity as a function of initial cloud size, turbulent atmospheric dissipation, and time. Vertical diffusivity is input as a function of time and height. Therefore, diurnal variations of turbulent diffusion in the boundary layer and effects of temperature inversions, etc. can be modeled. Nondiffusive cloud depletion mechanisms, such as dry deposition, washout, and radioactive decay, are also a part of this numerical model. An effluent cloud, produced by a reactor run at the Nuclear Rocket Development Station, Nevada, is discussed in this paper. Measurements on this cloud, for a period of two days, are compared to calculations with the above numerical cloud diffusion model. In general, there is agreement. within a factor of two, for airborne concentrations, cloud horizontal area, surface air concentrations, and dry deposition as airborne concentration decreased by seven orders of magnitude during the two-day period. (author)

  19. Sahara Dust Cloud

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Dust Particles Click on the image for Quicktime movie from 7/15-7/24 A continent-sized cloud of hot air and dust originating from the Sahara Desert crossed the Atlantic Ocean and headed towards Florida and the Caribbean. A Saharan Air Layer, or SAL, forms when dry air and dust rise from Africa's west coast and ride the trade winds above the Atlantic Ocean. These dust clouds are not uncommon, especially during the months of July and August. They start when weather patterns called tropical waves pick up dust from the desert in North Africa, carry it a couple of miles into the atmosphere and drift westward. In a sequence of images created by data acquired by the Earth-orbiting Atmospheric Infrared Sounder ranging from July 15 through July 24, we see the distribution of the cloud in the atmosphere as it swirls off of Africa and heads across the ocean to the west. Using the unique silicate spectral signatures of dust in the thermal infrared, AIRS can detect the presence of dust in the atmosphere day or night. This detection works best if there are no clouds present on top of the dust; when clouds are present, they can interfere with the signal, making it much harder to detect dust as in the case of July 24, 2005. In the Quicktime movie, the scale at the bottom of the images shows +1 for dust definitely detected, and ranges down to -1 for no dust detected. The plots are averaged over a number of AIRS observations falling within grid boxes, and so it is possible to obtain fractional numbers. [figure removed for brevity, see original site] Total Water Vapor in the Atmosphere Around the Dust Cloud Click on the image for Quicktime movie The dust cloud is contained within a dry adiabatic layer which originates over the Sahara Desert. This Saharan Air Layer (SAL) advances Westward over the Atlantic Ocean, overriding the cool, moist air nearer the surface. This burst of very dry air is visible in the AIRS retrieved total water

  20. A Framework to Improve Communication and Reliability Between Cloud Consumer and Provider in the Cloud

    OpenAIRE

    Vivek Sridhar

    2014-01-01

    Cloud services consumers demand reliable methods for choosing appropriate cloud service provider for their requirements. Number of cloud consumer is increasing day by day and so cloud providers, hence requirement for a common platform for interacting between cloud provider and cloud consumer is also on the raise. This paper introduces Cloud Providers Market Platform Dashboard. This will act as not only just cloud provider discoverability but also provide timely report to consumer on cloud ser...