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Sample records for atmospheric exposure chambers

  1. Response of potato to discontinuous exposures of atmospheric ethylene: results of a long-term experiment in open-top chambers and crop growth modelling

    NARCIS (Netherlands)

    Dueck, T.A.; Dijk, van C.J.; Grashoff, C.; Groenwold, J.; Schapendonk, A.H.C.M.; Tonneijck, A.E.G.

    2003-01-01

    A field experiment in open-top chambers (OTCs) was performed to quantitatively assess the growth and yield response of potato to discontinuous exposures to atmospheric ethylene (200, 400 and 800 ppb, applied twice weekly and 200 and 400 ppb applied 4 times weekly, each for 3 h/event). To evaluate

  2. Exposure of lambs to atmospheric ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, J.G.; Curtis, S.E.; Lewis, J.M.; Hinds, F.C.; Simon, J.

    1976-01-01

    Two trials were conducted to determine the effects of chronic exposure to atmospheric ammonia at a concentration of 75 ppm on weight gain and efficiency of feed conversion by lambs. Lambs were weighed and then randomly allotted to four dynamic air-pollutant exposure chambers. Initial weights (mean +/- SE) of lambs were 22.1 +/- .46 kg and 27.5 +/- 1.54 kg for trials 1 and 2, respectively (n=12 in both trials). Lambs in two chambers (controls) were maintained in an atmosphere of filtered room air. Lambs in the other two chambers (NH/sub 3/ -exposed) were exposed to an atmosphere of filtered air plus atmospheric ammonia at a concentration of 75 ppm. Exposure period was 28 days in both trials. Feed and water were available at all times. Lamb weight gain and feed disappearance were determined weekly. Upon termination of each trial, one lamb was randomly selected from each chamber, sacrificed, and gross and histopathologic structural changes noted. Weight gain and efficiency of feed conversion data for the two trials were combined for statistical analysis. Control lambs gained on the average .09 kg/day (.28 vs .19) more (P<.01) and consumed on the average .68 kg of feed (4.53 vs 5.21) less per kilogram of weight gain (P<.10) than did NH/sub 3/-exposed lambs. Ammonia-exposed lambs in both trials showed profuse lacrimation, severe coughing and sneezing, and profuse nasal discharge, which was bloody in some instances. Gross and histopathologic findings appeared to be qualitatively similar between treatments, but more pronounced in NH/sub 3/-exposed lambs.

  3. Atmospheric-pressure plasma decontamination/sterilization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Hans W. (Los Alamos, NM); Selwyn, Gary S. (Los Alamos, NM)

    2001-01-01

    An atmospheric-pressure plasma decontamination/sterilization chamber is described. The apparatus is useful for decontaminating sensitive equipment and materials, such as electronics, optics and national treasures, which have been contaminated with chemical and/or biological warfare agents, such as anthrax, mustard blistering agent, VX nerve gas, and the like. There is currently no acceptable procedure for decontaminating such equipment. The apparatus may also be used for sterilization in the medical and food industries. Items to be decontaminated or sterilized are supported inside the chamber. Reactive gases containing atomic and metastable oxygen species are generated by an atmospheric-pressure plasma discharge in a He/O.sub.2 mixture and directed into the region of these items resulting in chemical reaction between the reactive species and organic substances. This reaction typically kills and/or neutralizes the contamination without damaging most equipment and materials. The plasma gases are recirculated through a closed-loop system to minimize the loss of helium and the possibility of escape of aerosolized harmful substances.

  4. Therapeutic effect of bilastine in Japanese cedar pollinosis using an artificial exposure chamber (OHIO Chamber).

    Science.gov (United States)

    Hashiguchi, Kazuhiro; Wakabayashi, Ken-Ichiro; Togawa, Michinori; Saito, Akihiro; Okubo, Kimihiro

    2017-01-01

    Environmental exposure chambers have been used to expose subjects to aeroallergens to investigate the efficacy of prophylactic treatment with symptomatic agents in Japan. We first examined the therapeutic effect of bilastine (BIL), a novel non-sedative second-generation H 1 -antihistamine, in subjects with Japanese cedar pollinosis using an artificial exposure chamber (OHIO Chamber). This was a randomized, double-blind, four-way crossover, placebo- and active-controlled phase II study (trial registration number JapicCTI-132213). Subjects were exposed to cedar pollen (8000 grains/m 3 ) for 2 h on Day -1 and 4 h each on Day 1 and 2. BIL 10 or 20 mg, placebo, or fexofenadine hydrochloride (FEX) 60 mg was administered orally 1 h after the start of pollen exposure on Day 1. Placebo or FEX was administered 12 h after the first dosing. The primary efficacy endpoint was the sum of total nasal symptom score (TNSS) from 0 to 3 h after the Day 1 dosing. We enrolled 136 subjects and the sum of TNSS on Day 1 of the three active treatments was significantly lower than that of placebo and was maintained up to 26 h after the first dosing (Day 2). The sum of TNSS or sneezing score on Day 1 after BIL 20 mg was more significantly decreased than after FEX. Moreover, BIL showed a faster onset of action than FEX. We demonstrated the efficacy, rapid onset, and long duration of action of BIL in subjects with Japanese cedar pollinosis exposed to cedar pollen using the OHIO Chamber. Copyright © 2016 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  5. Development of a quality assured calibration method for the PSI radon chamber reference atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Schuler, C.; Butterweck-Dempewolf, G.; Vezzu, G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-08-01

    Radon detectors and measuring instruments are calibrated at the PSI Reference Laboratory for Radon Gas Concentration Measurements by exposing them to a calibrated radon reference atmosphere in the PSI radon chamber. A sophisticated and quality assured calibration technique was developed which guarantees the traceability of this radon chamber reference atmosphere to standards of internationally acknowledged primary laboratories. (author) 2 figs., 2 refs.

  6. Mutagenicity in Salmonella of a Simulated Urban-Smog Atmosphere Generated Using a Mobile Reaction Chamber

    Science.gov (United States)

    The EPA Mobile Reaction Chamber (MRC) is a 24-foot trailer containing a 14.3-m3 Teflon lined photochemical chamber used to generate simulated urban atmospheres. Photochemistry in the MRC is catalyzed by 120 fluorescent bulbs evenly mixed with black light bulbs and UV bulbs (300 &...

  7. Dependence of SOA oxidation on organic aerosol mass concentration and OH exposure: experimental PAM chamber studies

    Directory of Open Access Journals (Sweden)

    E. Kang

    2011-02-01

    Full Text Available The oxidation of secondary organic aerosol (SOA is studied with mass spectra analysis of SOA formed in a Potential Aerosol Mass (PAM chamber, a small flow-through photo-oxidation chamber with extremely high OH and ozone levels. The OH exposure from a few minutes in the PAM chamber is similar to that from days to weeks in the atmosphere. The mass spectra were measured with a Quadrupole Aerosol Mass Spectrometer (Q-AMS for SOA formed from oxidation of α-pinene, m-xylene, p-xylene, and a mixture of the three. The organic mass fractions of m/z 44 (CO2+ and m/z 43 (mainly C2H3O+, named f44 and f43 respectively, are used as indicators of the degree of organic aerosol (OA oxidation that occurs as the OA mass concentration or the OH exposure are varied. The degree of oxidation is sensitive to both. For a fixed OH exposure, the degree of oxidation initially decreases rapidly and then more slowly as the OA mass concentration increases. For fixed initial precursor VOC amounts, the degree of oxidation increases linearly with OH exposure, with f44 increasing and f43 decreasing. In this study, the degree of SOA oxidation spans much of the range observed in the atmosphere. These results, while sensitive to the determination of f44 and f43, provide evidence that some characteristics of atmospheric OA oxidation can be generated in a PAM chamber. For all measurements in this study, the sum of f44 and f43 is 0.25 ± 0.03, so that the slope of a linear regression is approximately −1 on an f44 vs. f43 plot. This constancy of the sum suggests that these ions are complete proxies for organic mass in the OA studied.

  8. Ultrasonic anechoic chamber qualification: accounting for atmospheric absorption and transducer directivity.

    Science.gov (United States)

    Jenny, Trevor; Anderson, Brian E

    2011-08-01

    Qualifying an anechoic chamber for frequencies that extend into the ultrasonic range is necessary for research work involving airborne ultrasonic sound. The ANSI S12.55/ISO 3745 standard which covers anechoic chamber qualification does not extend into the ultrasonic frequency range, nor have issues pertinent to this frequency range been fully discussed in the literature. An increasing number of technologies employ ultrasound; hence the need for an ultrasonic anechoic chamber. This paper will specifically discuss the need to account for atmospheric absorption and issues pertaining to source transducer directivity by presenting some results for qualification of a chamber at Brigham Young University.

  9. Carbon wire chamber at sub-atmospheric pressure

    Science.gov (United States)

    Charles, G.; Audouin, L.; Bettane, J.; Dupre, R.; Genolini, B.; Hammoudi, N.; Imre, M.; Le Ven, V.; Maroni, A.; Mathon, B.; Nguyen Trung, T.; Rauly, E.

    2017-05-01

    Present in many experiments, wire and drift chambers have been used in a large variety of shapes and configurations during the last decades. Nevertheless, their readout elements has not evolved much: tungsten, sometimes gold-plated or aluminum, wires. By taking advantage of the developments in the manufacture of conducting carbon fiber, we could obtain interesting improvements for wire detectors. In this article, we present recent tests and simulations using carbon fibers to readout signal in place of traditional tungsten wires. Unlike metallic wires, their low weight guaranties a reduced quantity of material in the active area.

  10. Interferences of commercial NO2 instruments in the urban atmosphere and in a smog chamber

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2012-01-01

    Full Text Available Reliable measurements of atmospheric trace gases are necessary for both, a better understanding of the chemical processes occurring in the atmosphere, and for the validation of model predictions. Nitrogen dioxide (NO2 is a toxic gas and is thus a regulated air pollutant. Besides, it is of major importance for the oxidation capacity of the atmosphere and plays a pivotal role in the formation of ozone and acid precipitation. Detection of NO2 is a difficult task since many of the different commercial techniques used are affected by interferences. The chemiluminescence instruments that are used for indirect NO2 detection in monitoring networks and smog chambers use either molybdenum or photolytic converters and are affected by either positive (NOy or negative interferences (radical formation in the photolytic converter. Erroneous conclusions on NO2 can be drawn if these interferences are not taken into consideration. In the present study, NO2 measurements in the urban atmosphere, in a road traffic tunnel and in a smog-chamber using different commercial techniques, i.e. chemiluminescence instruments with molybdenum or photolytic converters, a Luminol based instrument and a new NO2-LOPAP, were compared with spectroscopic techniques, i.e. DOAS and FTIR. Interferences of the different instruments observed during atmospheric measurements were partly characterised in more detail in the smog chamber experiments. Whereas all the commercial instruments showed strong interferences, excellent agreement was obtained between a new NO2-LOPAP instrument and the FTIR technique for the measurements performed in the smog chamber.

  11. Planetary Atmosphere and Surfaces Chamber (PASC): A Platform to Address Various Challenges in Astrobiology

    Science.gov (United States)

    Mateo-Marti, Eva

    2014-08-01

    The study of planetary environments of astrobiological interest has become a major challenge. Because of the obvious technical and economical limitations on in situ planetary exploration, laboratory simulations are one of the most feasible research options to make advances both in planetary science and in developing a consistent description of the origin of life. With this objective in mind, we applied vacuum technology to the design of versatile vacuum chambers devoted to the simulation of planetary atmospheres' conditions. These vacuum chambers are able to simulate atmospheres and surface temperatures representative of the majority of planetary objects, and they are especially appropriate for studying the physical, chemical and biological changes induced in a particular sample by in situ irradiation or physical parameters in a controlled environment. Vacuum chambers are a promising potential tool in several scientific and technological fields, such as engineering, chemistry, geology and biology. They also offer the possibility of discriminating between the effects of individual physical parameters and selected combinations thereof. The implementation of our vacuum chambers in combination with analytical techniques was specifically developed to make feasible the in situ physico-chemical characterization of samples. Many wide-ranging applications in astrobiology are detailed herein to provide an understanding of the potential and flexibility of these experimental systems. Instruments and engineering technology for space applications could take advantage of our environment-simulation chambers for sensor calibration. Our systems also provide the opportunity to gain a greater understanding of the chemical reactivity of molecules on surfaces under different environments, thereby leading to a greater understanding of interface processes in prebiotic chemical reactions and facilitating studies of UV photostability and photochemistry on surfaces. Furthermore, the

  12. Technical Note: Intercomparison of formaldehyde measurements at the atmosphere simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    A. Wisthaler

    2008-04-01

    Full Text Available The atmosphere simulation chamber SAPHIR at the Research Centre Jülich was used to test the suitability of state-of-the-art analytical instruments for the measurement of gas-phase formaldehyde (HCHO in air. Five analyzers based on four different sensing principles were deployed: a differential optical absorption spectrometer (DOAS, cartridges for 2,4-dinitro-phenyl-hydrazine (DNPH derivatization followed by off-line high pressure liquid chromatography (HPLC analysis, two different types of commercially available wet chemical sensors based on Hantzsch fluorimetry, and a proton-transfer-reaction mass spectrometer (PTR-MS. A new optimized mode of operation was used for the PTR-MS instrument which significantly enhanced its performance for online HCHO detection at low absolute humidities.

    The instruments were challenged with typical ambient levels of HCHO ranging from zero to several ppb. Synthetic air of high purity and particulate-filtered ambient air were used as sample matrices in the atmosphere simulation chamber onto which HCHO was spiked under varying levels of humidity and ozone. Measurements were compared to mixing ratios calculated from the chamber volume and the known amount of HCHO injected into the chamber; measurements were also compared between the different instruments. The formal and blind intercomparison exercise was conducted under the control of an independent referee. A number of analytical problems associated with the experimental set-up and with individual instruments were identified, the overall agreement between the methods was fair.

  13. Overestimation of closed-chamber soil CO2 effluxes at low atmospheric turbulence

    DEFF Research Database (Denmark)

    Brændholt, Andreas; Larsen, Klaus Steenberg; Ibrom, Andreas

    2017-01-01

    Soil respiration (R-s) is an important component of ecosystem carbon balance, and accurate quantification of the diurnal and seasonal variation of R-s is crucial for a correct interpretation of the response of R-s to biotic and abiotic factors, as well as for estimating annual soil CO2 efflux rates......, such that the highest effluxes were now observed during daytime, and also led to a substantial decrease in the estimated annual soil CO2 efflux.By installing fans to produce continuous turbulent mixing of air around the soil chambers, we tested the hypothesis that overestimation of soil CO2 effluxes during low u(*) can...... atmospheric turbulence conditions. Other possible effects from using fans during soil CO2 efflux measurements are discussed. In conclusion, periods with low atmospheric turbulence may provide a significant source of error in R-s rates estimated by the use of closed-chamber tech-niques and erroneous data must...

  14. Biological monitoring of isocyanates and related amines. III. Test chamber exposure of humans to toluene diisocyanate.

    Science.gov (United States)

    Skarping, G; Brorson, T; Sangö, C

    1991-01-01

    Five men were exposed to toluene diisocyanate (TDI) atmospheres for 7.5 h. The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m3 stainless-steel test chamber. The mean air concentration of TDI was ca. 40 micrograms/m3, which corresponds to the threshold limit value (TLV) of Sweden. The inhaled doses of 2,4- and 2,6-TDI were ca. 120 micrograms. TDI in the test chamber air was determined by an HPLC method using the 9-(N-methylaminomethyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. After hydrolysis of plasma and urine, the related amines, 2,4- and 2,6-toluenediamine 2,4-, and 2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas-chromatography using selected ion monitoring (SIM) in the electron-impact mode. The urinary elimination of the TDAs showed a possible biphasic pattern, with rapid first phases for 2,4-TDA (mean t1/2 for the concentration in urine, 1.9 h) and for 2,6-TDA (mean t1/2 for the concentration in urine, 1.6 h). The cumulative amount of 2,4-TDA excreted in urine within 28 h ranged from 8% to 14% of the estimated dose of 2,4-TDI, and the cumulative amount of 2,6-TDA in urine ranged from 14% to 18% of the 2,6-TDI dose. The average urinary level of 2,4-TDA was 5 micrograms/l in the 6 to 8-h sample (range 2.8-9.6 micrograms/l), and the corresponding value for 2,6-TDA was 8.6 micrograms/l (range, 5.6-16.6 micrograms/l). Biological monitoring of exposure to 2,4- and 2,6-TDI by analysis of 2,4- and 2,6-TDA in urine is feasible.

  15. Overestimation of closed-chamber soil CO2 effluxes at low atmospheric turbulence

    Science.gov (United States)

    Brændholt, Andreas; Steenberg Larsen, Klaus; Ibrom, Andreas; Pilegaard, Kim

    2017-03-01

    Soil respiration (Rs) is an important component of ecosystem carbon balance, and accurate quantification of the diurnal and seasonal variation of Rs is crucial for a correct interpretation of the response of Rs to biotic and abiotic factors, as well as for estimating annual soil CO2 efflux rates. In this study, we measured Rs hourly for 1 year by automated closed chambers in a temperate Danish beech forest. The data showed a clear diurnal pattern of Rs across all seasons with higher rates during night-time than during daytime. However, further analysis showed a clear negative relationship between flux rates and friction velocity (u∗) above the canopy, suggesting that Rs was overestimated at low atmospheric turbulence throughout the year due to non-steady-state conditions during measurements. Filtering out data at low u∗ values removed or even inverted the observed diurnal pattern, such that the highest effluxes were now observed during daytime, and also led to a substantial decrease in the estimated annual soil CO2 efflux. By installing fans to produce continuous turbulent mixing of air around the soil chambers, we tested the hypothesis that overestimation of soil CO2 effluxes during low u∗ can be eliminated if proper mixing of air is ensured, and indeed the use of fans removed the overestimation of Rs rates during low u∗. Artificial turbulent air mixing may thus provide a method to overcome the problems of using closed-chamber gas-exchange measurement techniques during naturally occurring low atmospheric turbulence conditions. Other possible effects from using fans during soil CO2 efflux measurements are discussed. In conclusion, periods with low atmospheric turbulence may provide a significant source of error in Rs rates estimated by the use of closed-chamber techniques and erroneous data must be filtered out to obtain unbiased diurnal patterns, accurate relationships to biotic and abiotic factors, and before estimating Rs fluxes over longer timescales.

  16. Planetary Atmosphere and Surfaces Chamber (PASC: A Platform to Address Various Challenges in Astrobiology

    Directory of Open Access Journals (Sweden)

    Eva Mateo-Marti

    2014-08-01

    Full Text Available The study of planetary environments of astrobiological interest has become a major challenge. Because of the obvious technical and economical limitations on in situ planetary exploration, laboratory simulations are one of the most feasible research options to make advances both in planetary science and in developing a consistent description of the origin of life. With this objective in mind, we applied vacuum technology to the design of versatile vacuum chambers devoted to the simulation of planetary atmospheres’ conditions. These vacuum chambers are able to simulate atmospheres and surface temperatures representative of the majority of planetary objects, and they are especially appropriate for studying the physical, chemical and biological changes induced in a particular sample by in situ irradiation or physical parameters in a controlled environment. Vacuum chambers are a promising potential tool in several scientific and technological fields, such as engineering, chemistry, geology and biology. They also offer the possibility of discriminating between the effects of individual physical parameters and selected combinations thereof. The implementation of our vacuum chambers in combination with analytical techniques was specifically developed to make feasible the in situ physico-chemical characterization of samples. Many wide-ranging applications in astrobiology are detailed herein to provide an understanding of the potential and flexibility of these experimental systems. Instruments and engineering technology for space applications could take advantage of our environment-simulation chambers for sensor calibration. Our systems also provide the opportunity to gain a greater understanding of the chemical reactivity of molecules on surfaces under different environments, thereby leading to a greater understanding of interface processes in prebiotic chemical reactions and facilitating studies of UV photostability and photochemistry on surfaces

  17. [Effect of plant-associated methanolic bacteria on methane and methanol concentration dynamics in atmosphere of pressurized chamber].

    Science.gov (United States)

    Berkovich, Iu A; Doronina, N V; Fedorov, D N; Mukhamedieva, L N; Mikos, K N; Krivobock, N M; Smolianin, V G; Smolianina, S O; Shanturin, N A

    2010-01-01

    Stability of Chinese cabbage crop colonization by methanolic bacteria Methylovorus mays, Methylomonas methanica and Methylosinus trichosporium inoculated using a space-applicable method was evaluated. Besides, trends of methane and methanol concentrations in the pressurized chamber with inoculated and uninoculated crops were calculated. Methylovorus mays and Methylosinus trichosporium were shown to establish more stable colonization as compared to Methylomonas methanica. Also, stable association of methanolic bacteria with plants reduced airborne methanol 75% faster owing to its uptake by bacteria. Therefore, inoculation of these microorganisms can be viewed as a promising method of controlling volatile pollutants in space vehicle atmosphere. Methane drop after 6-hour exposure to inoculated control and test crops was not significant.

  18. Atmospheric scanning electron microscope system with an open sample chamber: Configuration and applications

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, Hidetoshi, E-mail: hinishiy@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Koizumi, Mitsuru, E-mail: koizumi@jeol.co.jp [JEOL Technics Ltd., 2-6-38 Musashino, Akishima, Tokyo 196-0021 (Japan); Ogawa, Koji, E-mail: kogawa@jeol.co.jp [JEOL Technics Ltd., 2-6-38 Musashino, Akishima, Tokyo 196-0021 (Japan); Kitamura, Shinich, E-mail: kitamura@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Konyuba, Yuji, E-mail: ykonyuub@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Watanabe, Yoshiyuki, E-mail: watanabeyoshiy@pref.yamagata.jp [Yamagata Research Institute of Technology, 2-2-1, Matsuei, Yamagata 990-2473 (Japan); Ohbayashi, Norihiko, E-mail: n.ohbayashi@m.tohoku.ac.jp [Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Fukuda, Mitsunori, E-mail: nori@m.tohoku.ac.jp [Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Suga, Mitsuo, E-mail: msuga@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Sato, Chikara, E-mail: ti-sato@aist.go.jp [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-4, Umezono, Tsukuba 305-8568 (Japan)

    2014-12-15

    An atmospheric scanning electron microscope (ASEM) with an open sample chamber and optical microscope (OM) is described and recent developments are reported. In this ClairScope system, the base of the open sample dish is sealed to the top of the inverted SEM column, allowing the liquid-immersed sample to be observed by OM from above and by SEM from below. The optical axes of the two microscopes are aligned, ensuring that the same sample areas are imaged to realize quasi-simultaneous correlative microscopy in solution. For example, the cathodoluminescence of ZnO particles was directly demonstrated. The improved system has (i) a fully motorized sample stage, (ii) a column protection system in the case of accidental window breakage, and (iii) an OM/SEM operation system controlled by a graphical user interface. The open sample chamber allows the external administration of reagents during sample observation. We monitored the influence of added NaCl on the random motion of silica particles in liquid. Further, using fluorescence as a transfection marker, the effect of small interfering RNA-mediated knockdown of endogenous Varp on Tyrp1 trafficking in melanocytes was examined. A temperature-regulated titanium ASEM dish allowed the dynamic observation of colloidal silver nanoparticles as they were heated to 240 °C and sintered. - Highlights: • Atmospheric SEM (ASEM) allows observation of samples in liquid or gas. • Open sample chamber allows in situ monitoring of evaporation and sintering processes. • in situ monitoring of processes during reagent administration is also accomplished. • Protection system for film breakage is developed for ASEM. • Usability of ASEM has been improved significantly including GUI control.

  19. Quality assurance for radon exposure chambers at the National Air and Radiation Environmental Laboratory, Montgomery, Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Semler, M.O.; Sensintaffar, E.L. [National Air and Radiation Environmental Laboratory, Montgomery, AL (United States)

    1993-12-31

    The Office of Radiation and Indoor Air, U.S. Environmental Protection Agency (EPA), operates six radon exposure chambers in its two laboratories, the National Air and Radiation Environmental Laboratory (NAREL) in Montgomery, Alabama, and the Las Vegas Facility, Las Vegas, Nevada. These radon exposure chambers are used to calibrate and test portable radon measuring instruments, test commercial suppliers of radon measurement services through the Radon Measurement Proficiency Program, and expose passive measurement devices to known radon concentrations as part of a quality assurance plan for federal and state studies measuring indoor radon concentrations. Both laboratories participate in national and international intercomparisons for the measurement of radon and are presently working with the National Institute of Standards and Technology (NIST) to receive a certificate of traceability for radon measurements. NAREL has developed an estimate of the total error in its calibration of each chamber`s continuous monitors as part of an internal quality assurance program. This paper discusses the continuous monitors and their calibration for the three chambers located in Montgomery, Alabama, as well as the results of the authors intercomparisons and total error analysis.

  20. Investigation of the β-pinene photooxidation by OH in the atmosphere simulation chamber SAPHIR

    Science.gov (United States)

    Kaminski, Martin; Fuchs, Hendrik; Acir, Ismail-Hakki; Bohn, Birger; Brauers, Theo; Dorn, Hans-Peter; Häseler, Rolf; Hofzumahaus, Andreas; Li, Xin; Lutz, Anna; Nehr, Sascha; Rohrer, Franz; Tillmann, Ralf; Vereecken, Luc; Wegener, Robert; Wahner, Andreas

    2017-06-01

    Besides isoprene, monoterpenes are the non-methane volatile organic compounds (VOCs) with the highest global emission rates. Due to their high reactivity towards OH, monoterpenes can dominate the radical chemistry of the atmosphere in forested areas. In the present study the photochemical degradation mechanism of β-pinene was investigated in the Jülich atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). One focus of this study is on the OH budget in the degradation process. Therefore, the SAPHIR chamber was equipped with instrumentation to measure radicals (OH, HO2, RO2), the total OH reactivity, important OH precursors (O3, HONO, HCHO), the parent VOC β-pinene, its main oxidation products, acetone and nopinone and photolysis frequencies. All experiments were carried out under low-NO conditions ( ≤ 300 ppt) and at atmospheric β-pinene concentrations ( ≤ 5 ppb) with and without addition of ozone. For the investigation of the OH budget, the OH production and destruction rates were calculated from measured quantities. Within the limits of accuracy of the instruments, the OH budget was balanced in all β-pinene oxidation experiments. However, even though the OH budget was closed, simulation results from the Master Chemical Mechanism (MCM) 3.2 showed that the OH production and destruction rates were underestimated by the model. The measured OH and HO2 concentrations were underestimated by up to a factor of 2, whereas the total OH reactivity was slightly overestimated because the model predicted a nopinone mixing ratio which was 3 times higher than measured. A new, theory-derived, first-generation product distribution by Vereecken and Peeters (2012) was able to reproduce the measured nopinone time series and the total OH reactivity. Nevertheless, the measured OH and HO2 concentrations remained underestimated by the numerical simulations. These observations together with the fact that the measured OH budget

  1. Investigation of aromatic compound degradation under atmospheric conditions in the outdoor simulation chamber SAPHIR

    Science.gov (United States)

    Nehr, Sascha; Bohn, Birger; Rohrer, Franz; Tillmann, Ralf; Wegener, Robert; Dorn, Hans-Peter; Häseler, Rolf; Brauers, Theo; Wahner, Andreas

    2010-05-01

    Ozone is produced in the lower troposphere by the OH-initiated photooxidation of volatile organic compounds in the presence of NOx. Aromatic hydrocarbons from anthropogenic sources are a major contributor to the OH-reactivity and thus to ozone formation in urban areas [1]. Moreover, their degradation leads to formation of secondary organic aerosol. Aromatic compounds are therefore important trace constituents with regard to air quality. We will present the results of photooxidation experiments which were conducted in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich. The experiments were designed to investigate the degradation mechanisms of benzene and p-xylene, which are among the most abundant aromatics in urban air samples. Benzene and p-xylene were selected because they have high structural symmetry which limits the number of potential isomers of secondary products. The experiments were performed under low-NOx-conditions (≤ 2 ppb). SAPHIR was equipped with instruments for the measurement of the parent aromatics and their major oxidation products, OH radicals, important radical precursors (O3, HONO, HCHO), photolysis frequencies and particulate matter. As shown in previous studies, simulation chamber data from the photooxidation of aromatics cannot be explained satisfactorily with current photochemistry mechanisms. For example the MCMv3.1 tends to overestimate the ozone-concentration and to underestimate the OH-concentration [2]. In this study, we will contrast model calculations with experimental results to check if similar discrepancies can be observed in SAPHIR and how they can be resolved. Based on the results of this preparatory study, further simulation chamber experiments with special emphasis on the radical budget are scheduled in 2010. References: [1] J. G. Calvert, R. Atkinson, K.H. Becker, R.M. Kamens, J.H. Seinfeld, T.J. Wallington, G. Yarwood: The mechanisms of atmospheric oxidation of aromatic hydrocarbons, Oxford University

  2. Actinometric measurements of NO2 photolysis frequencies in the atmosphere simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    B. Bohn

    2005-01-01

    Full Text Available The simulation chamber SAPHIR at Forschungszentrum Jülich has UV permeable teflon walls facilitating atmospheric photochemistry studies under the influence of natural sunlight. Because the internal radiation field is strongly affected by construction elements, we use external, radiometric measurements of spectral actinic flux and a model to calculate mean photolysis frequencies for the chamber volume Bohn04B. In this work we determine NO2 photolysis frequencies j(NO2 within SAPHIR using chemical actinometry by injecting NO2 and observing the chemical composition during illumination under various external conditions. In addition to a photo-stationary approach, a time-dependent method was developed to analyse the data. These measurements had two purposes. Firstly, to check the model predictions with respect to diurnal and seasonal variations in the presence of direct sunlight and secondly to obtain an absolute calibration factor for the combined radiometry-model approach. We obtain a linear correlation between calculated and actinometric j(NO2. A calibration factor of 1.34±0.10 is determined, independent of conditions in good approximation. This factor is in line with expectations and can be rationalised by internal reflections within the chamber. Taking into account the uncertainty of the actinometric j(NO2, an accuracy of 13% is estimated for the determination of j(NO2 in SAPHIR. In separate dark experiments a rate constant of (1.93±0.12x10-14 cm3 s-1 was determined for the NO+O3 reaction at 298K using analytical and numerical methods of data analysis.

  3. Testing of the abiotic degradation of chemicals in the atmosphere: the smog chamber approach

    Energy Technology Data Exchange (ETDEWEB)

    Kloepffer, W.H.; Haag, F.; Kohl, E.G.; Frank, R.

    1988-06-01

    Methods for measuring the hydroxyl-, ozone-, and direct photochemical reactivity of a substance in one specially designed medium size smog chamber are described. Rate coefficients for the reaction of OH with n-hexane, n-heptane, ethene, ethyne, chloroform, trichloroethene, methanol, 2-propanol, benzene, o-xylene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, p-chloroaniline, naphthalene, acenaphthene, 1,4-dichloronaphthalene, biphenyl, and fluorenone are given and discussed. An upper limit of 5 X 10(-13) cm3/sec is given for the sum penta- and hexa-chlorobiphenyls (PCB). Rate coefficients for the ozone reaction are given for beta-pinene, limonene, delta 3-carene, cineol, vinyl chloride and 1,3-butadiene. In cases where the literature data are available for comparison, the rate coefficients (kappa OH and kappa O3) reported here compare favorably with the best data reported. The direct photochemical reactivity has been shown to be measurable if the chamber is cleaned carefully. Preliminary results on benzophenone are reported. The methods described here, except that of direct photochemical reactivity, are in agreement with those proposed to OECD. Moreover, part of the Draft OECD Test Guideline (Berlin, 1987) on Photochemical-Oxidative Degradation in the Atmosphere is based on work described here and on closely related work in other laboratories.

  4. A tunable diode laser absorption spectrometer for formaldehyde atmospheric measurements validated by simulation chamber instrumentation.

    Science.gov (United States)

    Catoire, V; Bernard, F; Mébarki, Y; Mellouki, A; Eyglunent, G; Daële, V; Robert, C

    2012-01-01

    A tunable diode laser absorption spectrometer (TDLAS) for formaldehyde atmospheric measurements has been set up and validated through comparison experiments with a Fourier transform infrared spectrometer (FT-IR) in a simulation chamber. Formaldehyde was generated in situ in the chamber from reaction of ethene with ozone. Three HCHO ro-vibrational line intensities (at 2909.71, 2912.09 and 2914.46 cm(-1)) possibly used by TDLAS were calibrated by FT-IR spectra simultaneously recorded in the 1600-3200 cm(-1) domain during ethene ozonolysis, enabling the on-line deduction of the varying concentration for HCHO in formation. The experimental line intensities values inferred confirmed the calculated ones from the updated HITRAN database. In addition, the feasibility of stratospheric in situ HCHO measurements using the 2912.09 cm(-1) line was demonstrated. The TDLAS performances were also assessed, leading to a 2sigma detection limit of 88 ppt in volume mixing ratio with a response time of 60 sec at 30 Torr and 294 K for 112 m optical path. As part of this work, the room-temperature rate constant of this reaction and the HCHO formation yield were found to be in excellent agreement with the compiled literature data.

  5. Investigation of MVK oxidation by OH in the atmosphere simulation chamber SAPHIR

    Science.gov (United States)

    Fuchs, Hendrik; Andres, Stefanie; Bohn, Birger; Häseler, Rolf; Hofzumahaus, Andreas; Holland, Frank; Li, Xin; Kaminski, Martin; Novelli, Anna; Rohrer, Franz; Tillmann, Ralf; Wegener, Robert; Wahner, Andreas

    2017-04-01

    Recent field campaigns showed concentrations of hydroxyl radical (OH) up to a factor of ten larger than predicted by current chemical models for high OH reactivity and low concentrations of nitric oxide (NO). These discrepancies were observed in forests, where isoprene oxidation turnover rates were large. Methyl-vinyl-ketone (MVK) is one of the major first generation products of isoprene oxidation. Here, we present the investigation of the MVK oxidation mechanism at different nitric oxide concentrations in the atmosphere simulation chamber SAPHIR in Juelich, Germany. Measurements of trace gases included a full set of accurate and precise radical measurements. Results of the experiments are compared to model predictions using the Master Chemical Mechanism and recently suggested new reaction pathways.

  6. Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

    Science.gov (United States)

    Fuchs, Hendrik; Novelli, Anna; Rolletter, Michael; Hofzumahaus, Andreas; Pfannerstill, Eva Y.; Kessel, Stephan; Edtbauer, Achim; Williams, Jonathan; Michoud, Vincent; Dusanter, Sebastien; Locoge, Nadine; Zannoni, Nora; Gros, Valerie; Truong, Francois; Sarda-Esteve, Roland; Cryer, Danny R.; Brumby, Charlotte A.; Whalley, Lisa K.; Stone, Daniel; Seakins, Paul W.; Heard, Dwayne E.; Schoemaecker, Coralie; Blocquet, Marion; Coudert, Sebastien; Batut, Sebastien; Fittschen, Christa; Thames, Alexander B.; Brune, William H.; Ernest, Cheryl; Harder, Hartwig; Muller, Jennifer B. A.; Elste, Thomas; Kubistin, Dagmar; Andres, Stefanie; Bohn, Birger; Hohaus, Thorsten; Holland, Frank; Li, Xin; Rohrer, Franz; Kiendler-Scharr, Astrid; Tillmann, Ralf; Wegener, Robert; Yu, Zhujun; Zou, Qi; Wahner, Andreas

    2017-10-01

    Hydroxyl (OH) radical reactivity (kOH) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapour, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements (limit of detection hydroxyl radicals, whereas the indirect comparative reactivity method (CRM) has a higher limit of detection of 2 s-1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapour or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected into the chamber to simulate urban and forested environments. Overall, the results show that the instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to reference measurements or to calculated reactivity were observed by CRM instruments in the presence of terpenes and oxygenated organic compounds (mixing ratio of OH reactants were up to 10 ppbv). In some of these experiments

  7. gamma. -converting plate system for neutrino-deuterium exposures in the FNAL 15-foot bubble chamber

    Energy Technology Data Exchange (ETDEWEB)

    Hanlon, J.; Mann, W.A.; Sommars, S.; Wald, H.

    1978-01-01

    During May 18-20 of this year the hydrogen-filled 15-foot bubble chamber at Fermilab was operated with an array of four half-inch thick stainless steel plates mounted in downstream portions of the fiducial volume. Notes from the test run, and results from a Monte Carlo study of efficiencies of the plate array for detection of photons and positrons in final states produced in a wide-band neutrino--deuterium exposure, are presented.

  8. A Radio Frequency Radiation Exposure System for Rodents based on Reverberation Chambers.

    Science.gov (United States)

    Capstick, Myles; Kuster, Niels; Kuehn, Sven; Berdinas-Torres, Veronica; Gong, Yijian; Wilson, Perry; Ladbury, John; Koepke, Galen; McCormick, David L; Gauger, James; Melnick, Ronald L

    2017-08-01

    In this paper we present the novel design features, their technical implementation, and an evaluation of the radio Frequency (RF) exposure systems developed for the National Toxicology Program (NTP) of the National Institute of Environmental Health Sciences (NIEHS) studies on the potential toxicity and carcinogenicity of 2nd and 3rd generation mobile-phone signals. The system requirements for this 2-year NTP cancer bioassay study were the tightly-controlled lifetime exposure of rodents (1568 rats and 1512 mice) to three power levels plus sham simulating typical daily, and higher, exposures of users of GSM and CDMA (IS95) signals. Reverberation chambers and animal housing were designed to allow extended exposure time per day for free-roaming individually-housed animals. The performance of the chamber was characterized in terms of homogeneity, stirred to unstirred energy, efficiency. The achieved homogeneity was 0.59 dB and 0.48 dB at 900 and 1900 MHz respectively. The temporal variation in the electric field strength was optimized to give similar characteristics to that of the power control of a phone in a real network using the two stirrers. Experimental dosimetry was performed to validate the SAR sensitivity and determine the SAR uniformity throughout the exposure volume; SAR uniformities of 0.46 dB and 0.40 dB, respectively, for rats and mice were achieved.

  9. Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    H. Fuchs

    2017-10-01

    Full Text Available Hydroxyl (OH radical reactivity (kOH has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapour, nitrogen oxides, various organic compounds by all instruments. The precision of the measurements (limit of detection  < 1 s−1 at a time resolution of 30 s to a few minutes is higher for instruments directly detecting hydroxyl radicals, whereas the indirect comparative reactivity method (CRM has a higher limit of detection of 2 s−1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO, water vapour or nitric oxide (NO. In further experiments, mixtures of organic reactants were injected into the chamber to simulate urban and forested environments. Overall, the results show that the instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to reference measurements or to calculated reactivity were observed by CRM instruments in

  10. Microbiological and biochemical aspects of Camembert-type cheeses depend on atmospheric composition in the ripening chamber.

    Science.gov (United States)

    Leclercq-Perlat, M-N; Picque, D; Riahi, H; Corrieu, G

    2006-08-01

    Camembert-type cheeses were prepared from pasteurized milk seeded with Kluyveromyces lactis, Geotrichum candidum, Penicillium camemberti, and Brevibacterium aurantiacum. Microorganism growth and biochemical dynamics were studied in relation to ripening chamber CO(2) atmospheric composition using 31 descriptors based on kinetic data. The chamber ripening was carried out under 5 different controlled atmospheres: continuously renewed atmosphere, periodically renewed atmosphere, no renewed atmosphere, and 2 for which CO(2) was either 2% or 6%. All microorganism dynamics depended on CO(2) level. Kluyveromyces lactis was not sensitive to CO(2) during its growth phases, but its death did depend on it. An increase of CO(2) led to a significant improvement in G. candidum. Penicillium camemberti mycelium development was enhanced by 2% CO(2). The equilibrium between P. camemberti and G. candidum populations was disrupted in favor of the yeast when CO(2) was higher than 4%. Growth of B. aurantiacum depended more on O(2) than on CO(2). Two ripening progressions were observed in relation to the presence of CO(2) at the beginning of ripening: in the presence of CO(2), the ripening was fast-slow, and in the absence of CO(2), it was slow-fast. The underrind was too runny if CO(2) was equal to or higher than 6%. The nitrogen substrate progressions were slightly related to ripening chamber CO(2) and O(2) levels. During chamber ripening, the best atmospheric condition to produce an optimum between microorganism growth, biochemical dynamics, and cheese appearance was a constant CO(2) level close to 2%.

  11. Intercomparison of NO3 radical detection instruments in the atmosphere simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    H.-P. Dorn

    2013-05-01

    Full Text Available The detection of atmospheric NO3 radicals is still challenging owing to its low mixing ratios (≈ 1 to 300 pptv in the troposphere. While long-path differential optical absorption spectroscopy (DOAS has been a well-established NO3 detection approach for over 25 yr, newly sensitive techniques have been developed in the past decade. This publication outlines the results of the first comprehensive intercomparison of seven instruments developed for the spectroscopic detection of tropospheric NO3. Four instruments were based on cavity ring-down spectroscopy (CRDS, two utilised open-path cavity-enhanced absorption spectroscopy (CEAS, and one applied "classical" long-path DOAS. The intercomparison campaign "NO3Comp" was held at the atmosphere simulation chamber SAPHIR in Jülich (Germany in June 2007. Twelve experiments were performed in the well-mixed chamber for variable concentrations of NO3, N2O5, NO2, hydrocarbons, and water vapour, in the absence and in the presence of inorganic or organic aerosol. The overall precision of the cavity instruments varied between 0.5 and 5 pptv for integration times of 1 s to 5 min; that of the DOAS instrument was 9 pptv for an acquisition time of 1 min. The NO3 data of all instruments correlated excellently with the NOAA-CRDS instrument, which was selected as the common reference because of its superb sensitivity, high time resolution, and most comprehensive data coverage. The median of the coefficient of determination (r2 over all experiments of the campaign (60 correlations is r2 = 0.981 (quartile 1 (Q1: 0.949; quartile 3 (Q3: 0.994; min/max: 0.540/0.999. The linear regression analysis of the campaign data set yielded very small intercepts (median: 1.1 pptv; Q1/Q3: −1.1/2.6 pptv; min/max: −14.1/28.0 pptv, and the slopes of the regression lines were close to unity (median: 1.01; Q1/Q3: 0.92/1.10; min/max: 0.72/1.36. The deviation of individual regression slopes from unity was always within the combined

  12. 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

  13. A new whole-body exposure chamber for human skin and lung challenge experiments--the generation of wheat flour aerosols

    National Research Council Canada - National Science Library

    Lidén, C; Lundgren, L; Skare, L; Lidén, G; Tornling, G; Krantz, S

    1998-01-01

    A new whole-body exposure chamber for human skin and lung challenge offers possibilities for experimental exposure challenges carried out in clinical practice, for exposure of patients, in research...

  14. Workplace exposure and release of ultrafine particles during atmospheric plasma spraying in the ceramic industry.

    Science.gov (United States)

    Viana, M; Fonseca, A S; Querol, X; López-Lilao, A; Carpio, P; Salmatonidis, A; Monfort, E

    2017-12-01

    Atmospheric plasma spraying (APS) is a frequently used technique to produce enhanced-property coatings for different materials in the ceramic industry. This work aimed to characterise and quantify the impact of APS on workplace exposure to airborne particles, with a focus on ultrafine particles (UFPs, Particle number, mass concentrations, alveolar lung deposited surface area concentration, and size distributions, in the range 10nm-20μm were simultaneously monitored at the emission source, in the potential worker breathing zone, and in outdoor air. Different input materials (known as feedstock) were tested: (a) micron-sized powders, and (b) suspensions containing submicron- or nano-sized particles. Results evidenced significantly high UFP concentrations (up to 3.3×106/cm3) inside the spraying chamber, which impacted exposure concentrations in the worker area outside the spraying chamber (up to 8.3×105/cm3). Environmental release of UFPs was also detected (3.9×105/cm3, outside the exhaust tube). Engineered nanoparticle (ENP) release to workplace air was also evidenced by TEM microscopy. UFP emissions were detected during the application of both micron-sized powder and suspensions containing submicron- or nano-sized particles, thus suggesting that emissions were process- (and not material-) dependent. An effective risk prevention protocol was implemented, which resulted in a reduction of UFP exposure in the worker area. These findings demonstrate the potential risk of occupational exposure to UFPs during atmospheric plasma spraying, and raise the need for further research on UFP formation mechanisms in high-energy industrial processes. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Peak nasal inspiratory flow as outcome for provocation studies in allergen exposure chambers

    DEFF Research Database (Denmark)

    Boelke, Georg; Berger, Uwe; Bergmann, Karl-Christian

    2017-01-01

    parameters are preferred. Despite its practicability, the objective parameter peak nasal inspiratory flow (PNIF) has been rarely used for allergy trials in the setting of allergen exposure chambers. This study aims to evaluate PNIF as an outcome parameter for provocation studies in AECs. METHODS...... during a challenge using a portable PNIF meter. RESULTS: 86 subjects participated in 203 challenges, altogether. House dust mite provocations caused the greatest reduction in PNIF values, followed by grass pollen and birch pollen. Provocations with every allergen or pollen concentration led...... to a significant decrease (p flow, height and weight, and inverse correlations between PNIF and total nasal symptom score, nasal congestion score and visual analog scale of overall subjective...

  16. Improving Single-Chamber Solid Oxide Fuel Cell Performance by Plasma Treatment Using an Atmospheric-Pressure Helium Plasma Jet

    Science.gov (United States)

    Kanazawa, Seiji; Iwao, Tadasuke; Akamine, Shuichi; Ichiki, Ryuta

    2011-08-01

    An atmospheric-pressure helium plasma jet was used for the surface treatment of the electrodes in single-chamber solid oxide fuel cells (SC-SOFCs). The jet-type plasma source used in this study is suitable for the continuous and fine-area processing of materials, such as patterned electrodes. The basic plasma property was investigated by optical emission spectroscopy. Improvement in the performance of SC-SOFC was observed for the plasma-treated cell. From the scanning electron microscopy (SEM) observation, it was found that the surface morphology of the cell was largely changed. The increase in the area of the three-phase boundary among the electrode, electrolyte, and gas phase promoted electrochemical reactions. Under single-chamber operation condition at 850 °C, an open circuit voltage of 650 mV and a maximum power density of approximately 75 mW/cm2 were achieved for a coplanar-type cell.

  17. Changes in fluorescence spectra of bioaerosols exposed to ozone in a laboratory reaction chamber to simulate atmospheric aging.

    Science.gov (United States)

    Santarpia, Joshua L; Pan, Yong-Le; Hill, Steven C; Baker, Neal; Cottrell, Brian; McKee, Laura; Ratnesar-Shumate, Shanna; Pinnick, Ronald G

    2012-12-31

    A laboratory system for exposing aerosol particles to ozone and rapidly measuring the subsequent changes in their single-particle fluorescence is reported. The system consists of a rotating drum chamber and a single-particle fluorescence spectrometer (SPFS) utilizing excitation at 263 nm. Measurements made with this system show preliminary results on the ultra-violet laser-induced-fluorescence (UV-LIF) spectra of single aerosolized particles of Yersinia rohdei, and of MS2 (bacteriophage) exposed to ozone. When bioparticles are exposed in the chamber the fluorescence emission peak around 330 nm: i) decreases in intensity relative to that of the 400-550 nm band; and ii) shifts slightly toward shorter-wavelengths (consistent with further drying of the particles). In these experiments, changes were observed at exposures below the US Environmental Protection Agency (EPA) limits for ozone.

  18. Atmospheric degradation of lindane and 1,3-dichloroacetone in the gas phase. Studies at the EUPHORE simulation chamber.

    Science.gov (United States)

    Vera, Teresa; Borrás, Esther; Chen, Jianmin; Coscollá, Clara; Daële, Véronique; Mellouki, Abdelwahid; Ródenas, Milagros; Sidebottom, Howard; Sun, Xiaomin; Yusá, Vicent; Zhang, Xue; Muñoz, Amalia

    2015-11-01

    The gas-phase degradation of lindane (γ-isomer of hexachlorocyclohexane) towards OH radical was investigated under atmospheric conditions at the large outdoor European simulation chamber (EUPHORE) in Valencia, Spain. The rate coefficient for the reaction of hydroxyl radicals with lindane was measured using a conventional relative rate technique leading to a value of kOH(lindane)=(6.4±1.6)×10(-13) cm(3) molecule(-1) s(-1) at 300±5 K and atmospheric pressure. The results suggest that the tropospheric lifetime of lindane with respect to OH radicals is approximately 20 days. The product distribution studies on the OH-initiated oxidation of lindane provided evidence that the major initial carbon-containing oxidation product is pentachlorocyclohexanone. 1,3-Dichloroacetone was employed as a model compound for pentachlorocyclohexanone, and an investigation of its photolysis and reaction with OH radicals under atmospheric conditions was carried out. The data indicate that the atmospheric degradation of pentachlorocyclohexanone would be relatively rapid, and would not form persistent organic compounds. Theoretical study was also employed to calculate possible degradation pathways. Mechanism for reaction of lindane with OH radicals is proposed, and C-Cl bond cleavage is discussed. OH abstraction is considered to be a reasonable way for Cl to escape during degradation. The atmospheric implications of the use of lindane as an insecticide are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Design and assembly of an experimental laboratory for the study of atmosphere-plant interactions in the system of fumigation chambers.

    Science.gov (United States)

    Souza, S R; Pagliuso, J D

    2009-11-01

    An experimental laboratory was designed and assembled at the Botanical Institute of São Paulo, Brazil, in order to research atmosphere-plant interactions through the use of a system of fumigation chambers. A system of three "closed" fumigation chambers was designed to be used inside or outside the laboratory. The system was built to be used with a single pollutant or a mix of them. The innovation in this system is to allow chemical reactions inside the chambers that simulate atmospheric chemistry, especially photochemical processes involving high levels of ozone. Assessment of the performance and applicability of the system was based on the response of Nicotiana tabacum Bel W3 exposed to ozone produced alternatively by a generator and inside the chamber by reactions of its precursors. The results showed that the system can be well applied to the study of atmospheric chemistry interactions and the effects on plants.

  20. Miniature anechoic chamber for chronic exposure of small animals to plane-wave microwave fields.

    Science.gov (United States)

    Guy, A W

    1979-12-01

    A system of miniature anechoic chambers for chronically exposing a sizeable number of animals to microwave radiation was developed in which each animal can be individually exposed to microwaves or sham-exposed under controlled environmental conditions. Each animal is supplied with food and water by means designed to eliminate undesirable perturbations of the field. Field patterns in each chamber correspond closely to those made in large anechoic chambers; measurements indicate that a power density of 169 microW/cm2 per watt of input power can be provided, which results in peak SAR levels of 0.37 W/kg in cadavers of exposed rats.

  1. Intercomparison of measurements of NO2 concentrations in the atmosphere simulation chamber SAPHIR during the NO3Comp campaign

    Directory of Open Access Journals (Sweden)

    H. Fuchs

    2010-01-01

    Full Text Available NO2 concentrations were measured by various instruments during the NO3Comp campaign at the atmosphere simulation chamber SAPHIR at Forschungszentrum Jülich, Germany, in June 2007. Analytical methods included photolytic conversion with chemiluminescence (PC-CLD, broadband cavity ring-down spectroscopy (BBCRDS, pulsed cavity ring-down spectroscopy (CRDS, incoherent broadband cavity-enhanced absorption spectroscopy (IBB\\-CEAS, and laser-induced fluorescence (LIF. All broadband absorption spectrometers were optimized for the detection of the main target species of the campaign, NO3, but were also capable of detecting NO2 simultaneously with reduced sensitivity. NO2 mixing ratios in the chamber were within a range characteristic of polluted, urban conditions, with a maximum mixing ratio of approximately 75 ppbv. The overall agreement between measurements of all instruments was excellent. Linear fits of the combined data sets resulted in slopes that differ from unity only within the stated uncertainty of each instrument. Possible interferences from species such as water vapor and ozone were negligible under the experimental conditions.

  2. Studies on atmospheric degradation of diazinon in the EUPHORE simulation chamber.

    Science.gov (United States)

    Muñoz, Amalia; Person, Annaïg Le; Calvé, Stéphane Le; Mellouki, Abdelwahid; Borrás, Esther; Daële, Véronique; Vera, Teresa

    2011-10-01

    The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.2) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 302 ± 10 K and atmospheric pressure. The available evidence indicates that tropospheric degradation of diazinon is mainly controlled by reaction with OH radicals, and that the tropospheric lifetime with respect to the OH reaction is estimated to be around 4h whereas its lifetime with respect to the photolysis is higher than 1d under our conditions. Significant aerosol formation was observed following the reaction of diazinon with OH radicals, and the main carbon-containing products detected in the particle phase were hydroxydiazinon, hydroxydiazoxon and 2-isopropyl-6-methyl-pyrimidinyl-4-ol. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Effect of controlled adverse chamber environment exposure on tear functions in silicon hydrogel and hydrogel soft contact lens wearers.

    Science.gov (United States)

    Kojima, Takashi; Matsumoto, Yukihiro; Ibrahim, Osama M A; Wakamatsu, Tais Hitomi; Uchino, Miki; Fukagawa, Kazumi; Ogawa, Junko; Dogru, Murat; Negishi, Kazuno; Tsubota, Kazuo

    2011-11-11

    To prospectively evaluate the effect of controlled adverse chamber environment (CACE) exposure on tear function, including tear osmolarity, in subjects wearing narafilcon A versus those wearing etafilcon A soft contact lens (SCL). Thirty-one healthy subjects with no history of contact lens wear (13 women, 18 men; average age, 30.5 ± 6.5 years) were randomly divided into age- and sex-matched groups (15 subjects wearing narafilcon A SCL; 16 subjects wearing etafilcon A SCL) and entered a CACE for 20 minutes. All subjects underwent tear osmolarity, tear evaporation rate, strip meniscometry, tear film breakup time, fluorescein vital staining, and functional visual acuity measurement before and after exposure to the controlled adverse chamber. The mean blink rate increased with significant deteriorations in the mean symptom VAS scores, mean tear osmolarity, tear evaporation rate, strip meniscometry score, and tear stability with CACE exposure along with a decrease in visual maintenance ratio in functional visual acuity testing in etafilcon A wearers. The mean symptom VAS scores, mean tear evaporation rate, tear stability, blink rates, and visual maintenance ratios did not change significantly in narafilcon A wearers after CACE exposure. This study suggested marked tear instability, higher tear osmolarity, and increased tear evaporation with marked dry eye and visual symptomatology in nonadapted hydrogel SCL wearers, suggesting that silicone hydrogel SCLs may be suitable for persons who live and work in cool, low-humidity, and windy environments, as tested in this study.

  4. A simple and versatile sup 2 sup 2 sup 2 Rn/ sup 2 sup 2 sup 0 Rn exposure chamber

    CERN Document Server

    Yu, K N; Guan, Z J

    2002-01-01

    A simple sup 2 sup 2 sup 2 Rn/ sup 2 sup 2 sup 0 Rn exposure chamber is described. The chamber is made of acrylic and has a volume of 0.41 m sup 3. The sup 2 sup 2 sup 2 Rn and sup 2 sup 2 sup 0 Rn sources can be operated independently or simultaneously. The concentrations of sup 2 sup 2 sup 2 Rn and sup 2 sup 2 sup 0 Rn were monitored by a continuous alpha spectrometer called RAD7. The capability of alpha spectrometry has removed the mutual interference between sup 2 sup 2 sup 0 Rn and sup 2 sup 2 sup 2 Rn, which is a major problem in measuring sup 2 sup 2 sup 0 Rn. Furthermore, the capability can also provide fast response to changes in the sup 2 sup 2 sup 2 Rn level and sup 2 sup 2 sup 0 Rn level in the exposure chamber, with temporal resolutions of about 20 and 2 min, respectively.

  5. Multiphase composition changes and reactive oxygen species formation during limonene oxidation in the new Cambridge Atmospheric Simulation Chamber (CASC)

    Science.gov (United States)

    Gallimore, Peter J.; Mahon, Brendan M.; Wragg, Francis P. H.; Fuller, Stephen J.; Giorio, Chiara; Kourtchev, Ivan; Kalberer, Markus

    2017-08-01

    The chemical composition of organic aerosols influences their impacts on human health and the climate system. Aerosol formation from gas-to-particle conversion and in-particle reaction was studied for the oxidation of limonene in a new facility, the Cambridge Atmospheric Simulation Chamber (CASC). Health-relevant oxidising organic species produced during secondary organic aerosol (SOA) formation were quantified in real time using an Online Particle-bound Reactive Oxygen Species Instrument (OPROSI). Two categories of reactive oxygen species (ROS) were identified based on time series analysis: a short-lived component produced during precursor ozonolysis with a lifetime of the order of minutes, and a stable component that was long-lived on the experiment timescale (˜ 4 h). Individual organic species were monitored continuously over this time using Extractive Electrospray Ionisation (EESI) Mass Spectrometry (MS) for the particle phase and Proton Transfer Reaction (PTR) MS for the gas phase. Many first-generation oxidation products are unsaturated, and we observed multiphase aging via further ozonolysis reactions. Volatile products such as C9H14O (limonaketone) and C10H16O2 (limonaldehyde) were observed in the gas phase early in the experiment, before reacting again with ozone. Loss of C10H16O4 (7-hydroxy limononic acid) from the particle phase was surprisingly slow. A combination of reduced C = C reactivity and viscous particle formation (relative to other SOA systems) may explain this, and both scenarios were tested in the Pretty Good Aerosol Model (PG-AM). A range of characterisation measurements were also carried out to benchmark the chamber against existing facilities. This work demonstrates the utility of CASC, particularly for understanding the reactivity and health-relevant properties of organic aerosols using novel, highly time-resolved techniques.

  6. Identification of Surrogate Measures of Diesel Exhaust Exposure in a Controlled Chamber Study

    Science.gov (United States)

    Exposure to diesel exhaust (DE) has been associated with acute cardiopulmonary and vascular responses, chronic noncancer health effects, and respiratory cancers in humans. To better understand DE exposures and eventually their related health effects, we established a controlled c...

  7. Biological monitoring of isocyanates and related amines. IV. 2,4- and 2,6-toluenediamine in hydrolysed plasma and urine after test-chamber exposure of humans to 2,4- and 2,6-toluene diisocyanate.

    Science.gov (United States)

    Brorson, T; Skarping, G; Sangö, C

    1991-01-01

    Two men were exposed to toluene diisocyanate (TDI) atmospheres at three different air concentrations (ca. 25, 50 and 70 micrograms/m3). The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m3 stainless-steel test chamber. The effective exposure period was 4 h. The isomeric composition of the air in the test chamber was 30% 2,4-TDI and 70% 2,6-TDI. The concentration of TDI in air of the test chamber was determined by an HPLC method using the 9-(N-methyl-amino-methyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. Following the hydrolysis of plasma and urine, the related amines, 2,4-toluenediamine (2,4-TDA) and 2,6-toluenediamine (2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas chromatography using selected ion monitoring (SIM) in the electron-impact mode. In plasma, 2,4- and 2,6-TDA showed a rapid-phase elimination half-time of ca. 2-5 h, and that for the slow phase was greater than 6 days. A connection was observed between concentrations of 2,4- and 2,6-TDI in air and the levels of 2,4- and 2,6-TDA in plasma. The cumulated amount of 2,4-TDA excreted in the urine over 24 h was ca. 15%-19% of the estimated inhaled dose of 2,4-TDI, and that of 2,6-TDA was ca. 17%-23% of the inhaled dose of 2,6-TDI. A connection was found between the cumulated (24-h) urinary excretion of 2,4- and 2,6-TDA and the air concentration of 2,4- and 2,6-TDI in the test chamber.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. An Initial Investigation into the Use of a Flux Chamber Technique to Measure Soil-Atmosphere Gas Exchanges from Application of Biosolids to UK Soils

    Directory of Open Access Journals (Sweden)

    S. M. Donovan

    2011-01-01

    Full Text Available While a significant amount of work has been conducted to assess the concentration of pollutants in soils and waterways near land that has been amended with biosolids, a relatively small body of research investigating emissions to atmosphere is available in the literature. Some studies have indicated that while the CO2 emissions from soils decrease with fertiliser application, the CH4 and N2O emissions might be increased, offsetting the benefit. The objective of the research presented in this paper was to address this gap, by the use of a flux chamber technique to measure soil-atmosphere gas exchanges from the application of biosolids to land. This was done by applying three different types of biosolids to soils and measuring gases at the soil-atmosphere interface. The measurements were taken on areas with three different types of vegetation. The gases were collected using a flux chamber technique and analysed by gas chromatography. The results presented here are preliminary findings of an ongoing experiment. Insignificant variation appeared to occur between different areas of vegetation; however, small variations in gas concentrations were observed indicating a need for continued monitoring of soil-atmosphere gas exchanges to determine the long-term impacts on the atmosphere and the environment.

  9. Pulmonary fibrotic response to inhalation of ZnO nanoparticles and toluene co-exposure through directed flow nose only exposure chamber.

    Science.gov (United States)

    Jain, Sonam; Rachamalla, Mahesh; Kulkarni, Apoorva; Kaur, Jasmine; Tikoo, Kulbhushan

    2013-11-01

    The increasing use of Zinc Oxide nanoparticles (ZnONPs) in paint industry is not supplemented with adequate toxicology data. This report focuses on the fibrogenic toxicity caused due to co-exposure of ZnONPs and toluene in male Wistar rats, exposed for 28 days, through directed flow nose only exposure chamber. The rats were grouped as air control, toluene control (200 ppm), zinc oxide control (10 mg/m(3)), low dose co-exposed (5 mg/m(3) ZnO and 200 ppm of toluene) and high dose co-exposed (10 mg/m(3) of ZnO and 200 ppm of toluene). Our study demonstrates that co-exposure of ZnONPs and toluene (as in paint industry), even at their respective permissible exposure level (5 mg/m(3) for ZnO and 200 ppm for toluene) have the potential to produce a progressive inflammatory and fibrotic response in the alveolar tissues of the lungs. We observed a significant increase in inflammatory markers in BAL fluid and elevated malondialdehyde (MDA) levels with lower levels of intracellular reduced glutathione (GSH) in lungs of rats of co-exposed group. Significant increase in the levels of pro-inflammatory mediators (IL-6, Ikβα, Cox-II, p-NF-κB) in lung tissues also indicated pulmonary damage. To best of our knowledge this is the first study which highlights the toxicity of co-exposed ZnO NPs and toluene.

  10. A dual-chamber method for quantifying the effects of atmospheric perturbations on secondary organic aerosol formation from biomass burning emissions

    Science.gov (United States)

    Tkacik, Daniel S.; Robinson, Ellis S.; Ahern, Adam; Saleh, Rawad; Stockwell, Chelsea; Veres, Patrick; Simpson, Isobel J.; Meinardi, Simone; Blake, Donald R.; Yokelson, Robert J.; Presto, Albert A.; Sullivan, Ryan C.; Donahue, Neil M.; Robinson, Allen L.

    2017-06-01

    Biomass burning (BB) is a major source of atmospheric pollutants. Field and laboratory studies indicate that secondary organic aerosol (SOA) formation from BB emissions is highly variable. We investigated sources of this variability using a novel dual-smog-chamber method that directly compares the SOA formation from the same BB emissions under two different atmospheric conditions. During each experiment, we filled two identical Teflon smog chambers simultaneously with BB emissions from the same fire. We then perturbed the smoke with UV lights, UV lights plus nitrous acid (HONO), or dark ozone in one or both chambers. These perturbations caused SOA formation in nearly every experiment with an average organic aerosol (OA) mass enhancement ratio of 1.78 ± 0.91 (mean ± 1σ). However, the effects of the perturbations were highly variable ranging with OA mass enhancement ratios ranging from 0.7 (30% loss of OA mass) to 4.4 across the set of perturbation experiments. There was no apparent relationship between OA enhancement and perturbation type, fuel type, and modified combustion efficiency. To better isolate the effects of different perturbations, we report dual-chamber enhancement (DUCE), which is the quantity of the effects of a perturbation relative to a reference condition. DUCE values were also highly variable, even for the same perturbation and fuel type. Gas measurements indicate substantial burn-to-burn variability in the magnitude and composition of SOA precursor emissions, even in repeated burns of the same fuel under nominally identical conditions. Therefore, the effects of different atmospheric perturbations on SOA formation from BB emissions appear to be less important than burn-to-burn variability.

  11. ATMOSPHERIC DISPERSION COEFFICIENTS & RADIOLOGICAL & TOXICOLOGICAL EXPOSURE METHODOLOGY FOR USE IN TANK FARMS

    Energy Technology Data Exchange (ETDEWEB)

    SANDGREN, K.R.

    2005-03-03

    This report presents the atmospheric dispersion coefficients used in Tank Farm safety analyses. The current revision also includes atmospheric dispersion coefficients used for analyses of the Demonstration Bulk Vitrification System. The basic equations for calculating radiological and toxicological exposures are also included.

  12. Test atmospheres of diisocyanates with special reference to controlled exposure of humans.

    Science.gov (United States)

    Brorson, T; Skarping, G; Renman, L; Sangö, C

    1989-01-01

    An all glass apparatus for the generation of air concentrations of 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI) and 1,6-hexamethylene diisocyanate (HDI) was developed. The generation principle was based on gas-phase permeation with permeation membranes of silicon rubber. In an 8 m3 stainless steel test chamber, low and steady TDI-and HDI atmospheres (1-100 micrograms/m3) could be maintained. The diisocyanate concentrations were determined by an HPLC method, using the 9-(N-methylaminomethyl)-anthracene reagent utilizing UV detection. The sum of diisocyanates and their related amines were determined by sampling in 0.4 M hydrochloric acid solution, and analysis by capillary gas chromatography with thermionic specific detection. Related amines were determined by sampling in ethanol - 0.2% KOH and analysis on GC-TSD. A continuous band-tape monitor was used for the determination of diisocyanates. Losses of diisocyanates in the test chamber were evaluated by measuring the TDI and HDI concentrations at the inlet respectively the outlet of the test chamber. At the outlet of the test chamber, ca 25% of the TDI respectively HDI concentrations were recovered. With a male subject in the test chamber ca 15% of the HDI concentration was recovered. The air flow through the test chamber was ca 10 m3/h. The changes in isomeric composition of airborne TDI, at stopped flow conditions, showed that the decay of the 2,4-isomer was faster than of the 2,6-isomer. No trace of the related amine toluene diamine (TDA) was detected in the test chamber, at TDI concentrations ranging from 20 to 50 micrograms/m3. Sampling losses due to sampling connections were evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Ageing and hygroscopicity variation of black carbon particles in Beijing measured by a quasi-atmospheric aerosol evolution study (QUALITY) chamber

    Science.gov (United States)

    Peng, Jianfei; Hu, Min; Guo, Song; Du, Zhuofei; Shang, Dongjie; Zheng, Jing; Zheng, Jun; Zeng, Limin; Shao, Min; Wu, Yusheng; Collins, Don; Zhang, Renyi

    2017-09-01

    Measurements of ageing and hygroscopicity variation of black carbon (BC) particles in Beijing were conducted using a 1.2 m3 quasi-atmospheric aerosol evolution study (QUALITY) chamber, which consisted of a bottom flow chamber through which ambient air was pulled continuously and an upper reaction chamber where ageing of BC particles occurred. Within the reaction chamber, transmission of the solar ultraviolet irradiation was approximately 50-60 %, wall loss of primary gaseous pollutants was negligible, and BC exhibited a half-lifetime of about 3-7 h. Typically, equilibrium for the primary gases, temperature and relative humidity between the reaction chamber and ambient air was established within 1 h. Rapid growth of BC particles occurred, with an average total growth of 77 ± 33 nm and average growth rate of 26 ± 11 nm h-1. Secondary organic aerosols (SOA) accounted for more than 90 % of the coating mass. The O / C ratio of SOA was 0.5, lower than the ambient level. The hygroscopic growth factor of BC particles decreased slightly with an initial thin coating layer because of BC reconstruction, but subsequently increased to 1.06-1.08 upon further ageing. The κ (kappa) values for BC particles and coating materials were calculated as 0.035 and 0.040 at the subsaturation and supersaturation conditions, respectively, indicating low hygroscopicity of coated SOA on BC particles. Hence, our results indicate that initial photochemical ageing of BC particles leads to considerable modifications to morphology and optical properties but does not appreciably alter the particle hygroscopicity in Beijing.

  14. Evaluation of methodologies for exposure assessment to atmospheric pollutants from a landfill site.

    Science.gov (United States)

    Mohan, Richard; Leonardi, Giovanni S; Robins, Alan; Jefferis, Stephan; Coy, Joanne; Wight, Jeremy; Murray, Virginia

    2009-04-01

    Epidemiological studies around landfill sites are limited by several factors, particularly a lack of accurate exposure assessment. Traditionally, exposure estimates are based on distance between place of residence and the landfill site. However, this measure of exposure ignores the effects that environmental factors may have upon exposure. A previous epidemiological study at a landfill site in the United Kingdom provided the basis for a case study to investigate exposure assessment methodologies that could support ongoing and future epidemiological work. Estimation of relative exposure to atmospheric pollutants near the site was refined using the Atmospheric Dispersion Modeling System (ADMS) 3.1. Annual average concentrations were calculated around the landfill site, which was modeled as an area source with a steady release rate over its entire active surface. Local meteorological and terrain data were used in the assessment. A geographical information system (GIS) was then used to link the results of the modeling to population and other data. Sensitivity studies were included to examine the variation of predicted exposure with several modeling assumptions and hence set other uncertainties in context. No simple relationship existed between the relative individual exposure measured by distance from the site and by dispersion modeling. A reassessment of exposure assessment in epidemiological studies around landfill sites was then undertaken with the refined estimates of exposure. This concluded that use of distance from the site as a proxy for exposure could lead to significant exposure misclassification in comparison with exposure assessment using atmospheric dispersion modeling and GIS. The study also indicated that assessment of peak exposure rates (i.e., extreme concentration levels) might be necessary in some epidemiological work. Optimum strategies for increasing the probability of observing effects in the more highly exposed population can be derived by

  15. Intercomparison of OH Radical Measurements by Long-Path Absorption and Laser Induced Fluorescence in the Atmosphere Simulation Chamber SAPHIR

    Science.gov (United States)

    Dorn, H.-P.; Brauers, T.; Greif, J.; Häseler, R.; Hofzumahaus, A.; Holland, F.; Rupp, L.

    2003-04-01

    A striking advantage of the SAPHIR chamber is the availability of two spectroscopic detection instruments for OH radicals: Laser-Induced Fluorescence Spectroscopy (LIF) and Long-Path Differential Optical Laser Absorption Spectroscopy (DOAS). Both instruments have already been compared in 1994 during the field measurement campaign POPCORN. They agreed well with a correlation coefficient of r=0.90 and a weighted linear fit with a slope of 1.09 +- 0.12. However, OH measurements in the simulation chamber differ significantly from measurements in ambient air. While DOAS measures OH as an integral value along the central longitudinal axis of SAPHIR, LIF samples the air locally and close (2 cm) to the floor of the chamber. Thus, the LIF measurements might be possibly affected by local concentration gradients caused by insufficient mixing of the chamber air or by deposition to the wall. On the other hand, if turbulent mixing of the chamber air is weak and high concentrations of ozone are used in experiments, the DOAS instrument might be subject to artificial formation of OH radicals in the air volume which is illuminated by the detection laser. This interference results from laser induced photolysis of ozone and the subsequent reaction of water vapor with the excited oxygen atoms formed. Thus it is of decisive importance to compare OH measurements from both instruments in order to investigate potential disturbing effects due to the specific sampling properties of both instruments within SAPHIR. We report on OH measurements accomplished simultaneously with both instruments using different trace gas compositions and experimental conditions.

  16. New insights into the degradation of terpenoids with OH: a study of the OH budget in the atmosphere simulation chamber SAPHIR

    Science.gov (United States)

    Kaminski, Martin; Fuchs, Hendrik; Acir, Ismail-Hakki; Bohn, Birger; Brauers, Theo; Dorn, Hans-Peter; Häseler, Rolf; Hofzumahaus, Andreas; Li, Xin; Lutz, Anna; Nehr, Sascha; Rohrer, Franz; Tillmann, Ralf; Wegener, Robert; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-05-01

    The hydroxyl radical (OH) is the main oxidation agent in the atmosphere during daytime. Recent field campaigns studying the radical chemistry in forested areas showed large discrepancies between measured and modeled OH concentration at low NOx conditions and when OH reactivity was dominated by VOC. These observations were only partially explained by the evidence for new efficient hydroxyl radical regeneration pathways in the isoprene oxidation mechanism. The question arises if other reactive VOCs with high global emission rates are also capable of additional OH recycling. Beside isoprene, monoterpenes and 2-methyl-3-buten-2-ol (MBO) are the volatile organic compounds (VOC) with the highest global emission rates. Due to their high reactivity towards OH monoterpenes and MBO can dominate the radical chemistry of the atmosphere in forested areas under certain conditions. In the present study the photochemical degradation mechanism of α-pinene, β-pinene, limonene, myrcene and MBO was investigated in the Jülich atmosphere simulation chamber SAPHIR. The focus of this study was in particular on the investigation of the OH budget in the degradation process. The photochemical degradation of these terpenoids was studied in a dedicated series of experiments in the years 2012 and 2013. The SAPHIR chamber was equipped with instrumentation to measure radicals (OH, HO2, RO2), the total OH reactivity, all important OH precursors (O3, HONO, HCHO), the parent VOC, its main oxidation products and photolysis frequencies to investigate the radical budget in the SAPHIR chamber. All experiments were carried out under low NOx conditions (≤ 2ppb) and atmospheric terpenoid concentrations (≤ 5ppb) with and without addition of ozone into the SAPHIR chamber. For the investigation of the OH budget all measured OH production terms were compared to the measured OH destruction. Within the limits of accuracy of the instruments the OH budget was balanced in all cases. Consequently unaccounted

  17. Response of the rhizosphere prokaryotic community of barley (Hordeum vulgare L.) to elevated atmospheric CO2 concentration in open-top chambers.

    Science.gov (United States)

    Szoboszlay, Márton; Näther, Astrid; Mitterbauer, Esther; Bender, Jürgen; Weigel, Hans-Joachim; Tebbe, Christoph C

    2017-08-01

    The effect of elevated atmospheric CO2 concentration [CO2 ] on the diversity and composition of the prokaryotic community inhabiting the rhizosphere of winter barley (Hordeum vulgare L.) was investigated in a field experiment, using open-top chambers. Rhizosphere samples were collected at anthesis (flowering stage) from six chambers with ambient [CO2 ] (approximately 400 ppm) and six chambers with elevated [CO2 ] (700 ppm). The V4 region of the 16S rRNA gene was PCR-amplified from the extracted DNA and sequenced on an Illumina MiSeq instrument. Above-ground plant biomass was not affected by elevated [CO2 ] at anthesis, but plants exposed to elevated [CO2 ] had significantly higher grain yield. The composition of the rhizosphere prokaryotic communities was very similar under ambient and elevated [CO2 ]. The dominant taxa were Bacteroidetes, Actinobacteria, Alpha-, Gamma-, and Betaproteobacteria. Elevated [CO2 ] resulted in lower prokaryotic diversity in the rhizosphere, but did not cause a significant difference in community structure. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  18. A new Open Top Chamber designed to test in situ effects of climatic and atmospheric changes on nitrogen fixation in boreal forest floor mosses

    Science.gov (United States)

    Bringuier, Charline; Bradley, Robert; Bellenger, Jean-Philippe; Morin, Hubert; Lindo, Zoë

    2014-05-01

    Biological nitrogen fixation (BNF) by cyanobacteria dwelling in forest floor moss layers is an important determinant of boreal black spruce forest productivity. Recent studies have suggested that these BNF rates may increase with increasing atmospheric CO2 and increasing temperature, as predicted by current weather models. This potential increase in BNF may be offset, however, by increasing atmospheric deposition of nitrogen, or by increasing demands for phosphorus (i.e. driving nodular ATP content) and for micronutrients such as Mo, Va and Fe (i.e. co-factors of nitrogenase enzyme). In order to study the relative and interactive effects of these factors controlling in situ BNF rates in boreal forest floor moss layers, a new Open Top Chamber (OTC) was developed in summer of 2013. The chambers measure 1.60 cm dia. × 60 cm height, and are equipped with an automated CO2 delivery system designed to maintain atmospheric daytime CO2 concentrations at 800 ppm, as well as buried heating coils that increase soil temperature by 4 ° C for 3 weeks in springtime. These 2 experimental factors are crossed in a full factorial (2 × 2) design that is replicated in 4 complete blocks. Each of the 16 OTCs is divided into 4 compartments, each of which are assigned 1 of 4 sub-plot factors. These include chronic additions of either atmospheric nitrogen, phosphorus, micronutrients or a non-amended control. Staring in summer 2014, a series of measurements will be made to assess the effects of treatments on BNF rates, cyanobacterial colonization and soil nitrogen cycling. Our poster will describe in detail the design and operation of the OTCs, as well as their construction and maintenance costs.

  19. Toxic corneal epithelial edema from exposure to high atmospheric concentration of toluene diisocyanates.

    Science.gov (United States)

    Luckenbach, M; Kielar, R

    1980-11-01

    Exposure to organic isocyanates in the atmosphere of a polyurethane-foam-producing company resulted in microcystic corneal epithelial edema and conjunctival injection localized primarily in the palpebral fissure. The degree of microcystic edema and decreased visual acuity appeared to be related to location, length of exposure, ventilation, temperature, and amount of chemicals and premold stored. Clearing time varied with amount of exposure. Moderate amounts of microcystic edema caused an average fall of one line in the visual acuity. Pain was absent. The toxic effect of the isocyanates on the metabolism of the corneal epithelium may be the cause of the corneal epithelial edema.

  20. ATMOSPHERIC DISPERSION COEFFICIENTS AND RADIOLOGICAL AND TOXICOLOGICAL EXPOSURE METHODOLOGY FOR USE IN TANK FARMS

    Energy Technology Data Exchange (ETDEWEB)

    GRIGSBY KM

    2011-04-07

    This report presents the atmospheric dispersion coefficients used in Tank Farms safety analysis. The basis equations for calculating radiological and toxicological exposures are also included. In this revision, the time averaging for toxicological consequence evaluations is clarified based on a review of DOE complex guidance and a review of tank farm chemicals.

  1. Time dependent electrical resistance of Bi 2(Te 0.4Se 0.6) 3 thin films in vacuum and on exposure to atmosphere

    Science.gov (United States)

    Damodara Das, V.; Selvaraj, S.

    1998-11-01

    Thin films of different thicknesses have been vacuum (2×10 -5 torr) deposited by the flash evaporation technique onto glass plates held at room temperature. In situ measurement of electrical resistance in vacuum (2×10 -5 torr) as a function of time was carried out until the resistance stabilized. Then, on exposure to air by controlled admittance of air into the vacuum chamber, it was found that the resistance of the films increased as pressure increased. After air was admitted up to atmospheric pressure, the resistance was also found to increase as a function of time in the atmosphere. Also, it was observed that the resistance of the film during re-evacuation does not retrace the previous path during the exposure of the films and thus the resistance variation is not reversible. The variation of resistance taking place in the films in vacuum with time is attributed to the coalescence process. The agglomeration rates for the films of different thicknesses were obtained from the linear behavior of ln( R/ R0) vs time plot. The resistance variation of the films during the exposure to air is attributed to oxygen adsorption. It was found that the annealed films are less influenced by the exposure compared to the as-grown films. Adsorption of oxygen takes place on the external and internal surfaces of the films. The films were found to be ESR active. Structural analysis was carried out using the XRD and TEM techniques.

  2. Development of a Novel Simulation Reactor for Chronic Exposure to Atmospheric Particulate Matter

    Science.gov (United States)

    Ye, Jianhuai; Salehi, Sepehr; North, Michelle L.; Portelli, Anjelica M.; Chow, Chung-Wai; Chan, Arthur W. H.

    2017-02-01

    Epidemiological studies have shown that air pollution is associated with the morbidity and mortality from cardiopulmonary diseases. Currently, limited experimental models are available to evaluate the physiological and cellular pathways activated by chronic multi-pollutant exposures. This manuscript describes an atmospheric simulation reactor (ASR) that was developed to investigate the health effects of air pollutants by permitting controlled chronic in vivo exposure of mice to combined particulate and gaseous pollutants. BALB/c mice were exposed for 1 hr/day for 3 consecutive days to secondary organic aerosol (SOA, a common particulate air pollutant) at 10-150 μg/m3, SOA (30 μg/m3) + ozone (65 ppb) or SOA + ozone (65 ppb) + nitrogen dioxide (NO2; 100 ppb). Daily exposure to SOA alone led to increased airway hyperresponsiveness (AHR) to methacholine with increasing SOA concentrations. Multi-pollutant exposure with ozone and/or NO2 in conjunction with a sub-toxic concentration of SOA resulted in additive effects on AHR to methacholine. Inflammatory cell recruitment to the airways was not observed in any of the exposure conditions. The ASR developed in this study allows us to evaluate the chronic health effects of relevant multi-pollutant exposures at ‘real-life’ levels under controlled conditions and permits repeated-exposure studies.

  3. Validation of the GA(2)LEN chamber for trials in allergy

    DEFF Research Database (Denmark)

    Zuberbier, Torsten; Abelson, Mark B; Akdis, Cezmi A

    2017-01-01

    BACKGROUND: Field clinical trials of pollen allergy are impacted by the impossibility to predict and to determine individual allergen exposure, due to many factors (e.g., pollen season, atmospheric variations, pollutants, lifestyles). Environmental exposure chambers (EEC), delivering a fixed amou...

  4. The systemic exposure to inhaled beclometasone/formoterol pMDI with valved holding chamber is independent of age and body size.

    Science.gov (United States)

    Govoni, Mirco; Piccinno, Annalisa; Lucci, Germano; Poli, Gianluigi; Acerbi, Daniela; Baronio, Roberta; Singh, Dave; Kuna, Piotr; Chawes, Bo L K; Bisgaard, Hans

    2015-02-01

    Asthma guidelines recommend prescription of inhaled corticosteroids at a reduced dosage in children compared to older patients in order to minimize the systemic exposure and risk of unwanted side effects. In children, pressurized metered dose inhalers (pMDI) are recommended in combination with a valved holding chamber (VHC) to overcome the problem of coordinating inhalation with actuation. However, the influence of age and body size on the systemic exposure of drugs to be administered via a pMDI with VHC is still not fully elucidated. Therefore, we aimed to compare the systemic exposure to the active ingredients of a fixed combination of beclometasone-dipropionate/formoterol-fumarate administered via pMDI with VHC in children, adolescents and adults. The pharmacokinetics of formoterol and beclometasone-17-monopropionate (active metabolite of beclometasone-dipropionate) was evaluated over 8 h from three studies, each performed in a different age and body size group. Children (7-11 years, n = 20), adolescents (12-17 years, n = 29) and adults (≥18 years, n = 24) received a single dose of beclometasone/formoterol (children: 200 μg/24 μg, adolescents and adults: 400 μg/24 μg) via pMDI with AeroChamber Plus™. The systemic exposure in children in comparison to adolescents was equivalent for formoterol while it was halved for beclometasone-17-monopropionate in accordance with the halved dose of beclometasone administered in children (90% CIs within 0.8-1.25 for formoterol and 0.4-0.625 for beclometasone-17-monopropionate). The systemic exposure to beclometasone-17-monopropionate and formoterol was equivalent between adolescents and adults. The systemic exposure to the active ingredients of a fixed dose combination of beclometasone/formoterol administered via pMDI with AeroChamber Plus™ correlates with the nominal dose independently of patient age and body size. Thus, dose reduction in relation to age when using a pMDI with VHC may be unnecessary for

  5. The systemic exposure to inhaled beclometasone/formoterol pMDI with valved holding chamber is independent of age and body size

    DEFF Research Database (Denmark)

    Govoni, Mirco; Piccinno, Annalisa; Lucci, Germano

    2015-01-01

    BACKGROUND: Asthma guidelines recommend prescription of inhaled corticosteroids at a reduced dosage in children compared to older patients in order to minimize the systemic exposure and risk of unwanted side effects. In children, pressurized metered dose inhalers (pMDI) are recommended in combina....../formoterol administered via pMDI with AeroChamber Plus™ correlates with the nominal dose independently of patient age and body size. Thus, dose reduction in relation to age when using a pMDI with VHC may be unnecessary for reducing the systemic exposure in children....... in combination with a valved holding chamber (VHC) to overcome the problem of coordinating inhalation with actuation. However, the influence of age and body size on the systemic exposure of drugs to be administered via a pMDI with VHC is still not fully elucidated. Therefore, we aimed to compare the systemic......-dipropionate) was evaluated over 8 h from three studies, each performed in a different age and body size group. Children (7-11 years, n = 20), adolescents (12-17 years, n = 29) and adults (≥18 years, n = 24) received a single dose of beclometasone/formoterol (children: 200 μg/24 μg, adolescents and adults: 400 μg/24 μg) via...

  6. 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

  7. Test chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    1999-01-01

    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

  8. Is atmospheric pollution exposure during pregnancy associated with individual and contextual characteristics? A nationwide study in France.

    Science.gov (United States)

    Ouidir, Marion; Lepeule, Johanna; Siroux, Valérie; Malherbe, Laure; Meleux, Frederik; Rivière, Emmanuel; Launay, Ludivine; Zaros, Cécile; Cheminat, Marie; Charles, Marie-Aline; Slama, Rémy

    2017-10-01

    Exposure to atmospheric pollutants is a danger for the health of pregnant mother and children. Our objective was to identify individual (socioeconomic and behavioural) and contextual factors associated with atmospheric pollution pregnancy exposure at the nationwide level. Among 14 921 women from the French nationwide ELFE (French Longitudinal Study of Children) mother-child cohort recruited in 2011, outdoor exposure levels of PM2.5, PM10 (particulate matter atmospheric pollutants with individual (maternal age, body mass index, parity, education level, relationship status, smoking status) and contextual (European Deprivation Index, urbanisation level) factors. Patterns of associations were globally similar across pollutants. For the CART approach, the highest tertile of exposure included mainly women not in a relationship living in urban and socially deprived areas, with lower education level. Linear regression models identified different determinants of atmospheric pollutants exposure according to the residential urbanisation level. In urban areas, atmospheric pollutants exposure increased with social deprivation, while in rural areas a U-shaped relationship was observed. We highlighted social inequalities in atmospheric pollutants exposure according to contextual characteristics such as urbanisation level and social deprivation and also according to individual characteristics such as education, being in a relationship and smoking status. In French urban areas, pregnant women from the most deprived neighbourhoods were those most exposed to health-threatening atmospheric pollutants. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  9. Exchange of atmospheric formic and acetic acids with trees and crop plants under controlled chamber and purified air conditions

    Science.gov (United States)

    Kesselmeier, J.; Bode, K.; Gerlach, C.; Jork, E.-M.

    We investigated the exchange of formic and acetic acids between the atmosphere and various tree species such as beech ( Fagus sylvatica L.), ash ( Fraxinus excelsior L.), spruce ( Picea abies L.) Karst, holm oak ( Quercus ilex L.), and birch ( Betula pendula L.). and some crop-plant species such as corn ( Zea mays, var. Banjo), pea ( Pisum sativum, var. Solara), barley ( Hordeum vulgare, var. Igri) and oat (Avena sativa, var. Wiesel). All experiments were done with dynamic enclosures flushed with purified oxidant-free air, containing only low or controlled amounts of the two acids. Significant and light-triggered emission of both acids from all tree species was observed. For one tree species (ash) a seasonal large increase in fall due to early leaf decomposition was found. The standard emission factors (30°C and PAR=1000 μmol m 2 s -1) given as (nmol m -2 min -1) for acetic and formic acids, respectively, were 8.1 and 29.7 (ash, autumn), 1.0 and 3.3 (ash, summer), 0.9 and 1.4 (beech), 0.7 and 1.45 (spruce), 1.9 and 2.4 (Holm oak) and 1.7 and 6.7 (birch). Rough estimation of global annual emissions range between 20 and 130 Gmol formic acid and 10 and 33 Gmol acetic acid. These numbers reflect a 15-30% contribution by forest emissions to the continental organic acid budget. As compared to the global total NMHC emissions low molecular weight organic acids are of minor importance. In contrast to the trees, none of the crop-plant species investigated showed an emission, but always a clear deposition of both acids. Both emission from trees as well as uptake by the agricultural plants could be related to transpiration rates and leaf conductances.

  10. Production of sugarcane bagasse-based activated carbon for formaldehyde gas removal from potted plants exposure chamber.

    Science.gov (United States)

    Mohamed, Elham F; El-Hashemy, Mohammed A; Abdel-Latif, Nasser M; Shetaya, Waleed H

    2015-12-01

    Agricultural wastes such as rice straw, sugar beet, and sugarcane bagasse have become a critical environmental issue due to growing agriculture demand. This study aimed to investigate the valorization possibility of sugarcane bagasse waste for activated carbon preparation. It also aimed to fully characterize the prepared activated carbon (BET surface area) via scanning electron microscope (SEM) and in terms of surface functional groups to give a basic understanding of its structure and to study the adsorption capacity of the sugarcane bagasse-based activated carbon using aqueous methylene blue (MB). The second main objective was to evaluate the performance of sugarcane bagasse-based activated carbon for indoor volatile organic compounds removal using the formaldehyde gas (HCHO) as reference model in two potted plants chambers. The first chamber was labeled the polluted chamber (containing formaldehyde gas without activated carbon) and the second was taken as the treated chamber (containing formaldehyde gas with activated carbon). The results indicated that the sugarcane bagasse-based activated carbon has a moderate BET surface area (557 m2/g) with total mesoporous volume and microporous volume of 0.310 and 0.273 cm3/g, respectively. The prepared activated carbon had remarkable adsorption capacity for MB. Formaldehyde removal rate was then found to be more than 67% in the treated chamber with the sugarcane bagasse-based activated carbon. The plants' responses for this application as dry weight, chlorophyll contents, and protein concentration were also investigated. Preparation of activated carbon from sugarcane bagasse (SCBAC) is a promising approach to produce cheap and efficient adsorbent for gas pollutants removal. It may be also a solution for the agricultural wastes problems in big cities, particularly in Egypt. MB adsorption tests suggest that the SCBAC have high adsorption capacity. Formaldehyde gas removal in the plant chambers indicates that the SCBAC have

  11. Exposure assessment method for products containing carbon nanotubes inside a test chamber with a Taber abrasion machine

    Science.gov (United States)

    Matsui, Yasuto; Nagaya, Taiki; Nobuyuki, Kato; Ishibashi, Tomonori; Yoneda, Minoru

    2017-06-01

    Polymer/carbon nanotube (CNT) composites exhibit distinguished properties, but more quantitative risk assessments on CNTs are necessary as research and development advances. One method to assess the exact risk is to evaluate the characteristics of nanoparticles generated from CNT composites during sanding or Taber abrasion tests. Some researchers have applied loads to CNT composites using Taber machines and analysed the particles using aerosol-measuring instruments and electron microscopes. However, employing aerosol-measuring instruments is challenging due to the small amount of generated particles. Additionally, the presence of abundant background nanoparticles in testing environments creates issues in quantitative measurements. Our research strives to develop an examination method to measure even very small amounts of nanoparticles generated by Taber abrasion. In this study, a Taber abrasion machine is miniaturised so that it fits inside a small chamber. A high-efficiency particulate air filter is attached to the chamber to eliminate background nanoparticles. Then CNT composites are abraded with the miniaturised Taber abrasion machine inside the chamber and the generated particles are analysed.

  12. Temporal trends in childhood leukaemia incidence following exposure to radioactive fallout from atmospheric nuclear weapons testing.

    Science.gov (United States)

    Wakeford, Richard; Darby, Sarah C; Murphy, Michael F G

    2010-05-01

    Notably raised rates of childhood leukaemia incidence have been found near some nuclear installations, in particular Sellafield and Dounreay in the United Kingdom, but risk assessments have concluded that the radiation doses estimated to have been received by children or in utero as a result of operations at these installations are much too small to account for the reported increases in incidence. This has led to speculation that the risk of childhood leukaemia arising from internal exposure to radiation following the intake of radioactive material released from nuclear facilities has been substantially underestimated. The radionuclides discharged from many nuclear installations are similar to those released into the global environment by atmospheric nuclear weapons testing, which was at its height in the late-1950s and early-1960s. Measurements of anthropogenic radionuclides in members of the general public resident in the vicinity of Sellafield and Dounreay have found levels that do not differ greatly from those in persons living remote from nuclear installations that are due to ubiquitous exposure to the radioactive debris of nuclear weapons testing. Therefore, if the leukaemia risk to children resulting from deposition within the body of radioactive material discharged from nuclear facilities has been grossly underestimated, then a pronounced excess of childhood leukaemia would have been expected as a consequence of the short period of intense atmospheric weapons testing. We have examined childhood leukaemia incidence in 11 large-scale cancer registries in three continents for which data were available at least as early as 1962. We found no evidence of a wave of excess cases corresponding to the peak of radioactive fallout from atmospheric weapons testing. The absence of a discernible increase in the incidence of childhood leukaemia following the period of maximum exposure to the radioactive debris of this testing weighs heavily against the suggestion that

  13. Technical Note: Formal blind intercomparison of HO2 measurements in the atmosphere simulation chamber SAPHIR during the HOxComp campaign

    Directory of Open Access Journals (Sweden)

    E. Schlosser

    2010-12-01

    Full Text Available Hydroperoxy radical (HO2 concentrations were measured during the formal blind intercomparison campaign HOxComp carried out in Jülich, Germany, in 2005. Three instruments detected HO2 via chemical conversion to hydroxyl radicals (OH and subsequent detection of the sum of OH and HO2 by laser induced fluorescence (LIF. All instruments were based on the same detection and calibration scheme. Because measurements by a MIESR instrument failed during the campaign, no absolute reference measurement was available, so that the accuracy of individual instruments could not be addressed. Instruments sampled ambient air for three days and were attached to the atmosphere simulation chamber SAPHIR during the second part of the campaign. Six experiments of one day each were conducted in SAPHIR, where air masses are homogeneously mixed, in order to investigate the performance of instruments and to determine potential interferences of measurements under well-controlled conditions. Linear correlation coefficients (R2 between measurements of the LIF instruments are generally high and range from 0.82 to 0.98. However, the agreement between measurements is variable. The regression analysis of the entire data set of measurements in SAPHIR yields slopes between 0.69 to 1.26 and intercepts are smaller than typical atmospheric daytime concentrations (less than 1 pptv. The quality of fit parameters improves significantly, when data are grouped into data subsets of similar water vapor concentrations. Because measurements of LIF instruments were corrected for a well-characterized water dependence of their sensitivities, this indicates that an unknown factor related to water vapor affected measurements in SAPHIR. Measurements in ambient air are also well-correlated, but regression parameters differ from results obtained from SAPHIR experiments. This could have been caused by differences in HO2 concentrations in the sampled air at the slightly different locations of

  14. Light Emission Requires Exposure to the Atmosphere in Ex Vivo Bioluminescence Imaging

    Directory of Open Access Journals (Sweden)

    Yusuke Inoue

    2006-04-01

    Full Text Available The identification of organs bearing luciferase activity by in vivo bioluminescence imaging (BLI is often difficult, and ex vivo imaging of excised organs plays a complementary role. This study investigated the importance of exposure to the atmosphere in ex vivo BLI. Mice were inoculated with murine pro-B cell line Ba/F3 transduced with firefly luciferase and p190 BCR-ABL. They were killed following in vivo BLI, and whole-body imaging was done after death and then after intraperitoneal air injection. In addition, the right knee was exposed and imaged before and after the adjacent bones were cut. Extensive light signals were seen on in vivo imaging. The luminescence disappeared after the animal was killed, and air injection restored the light emission from the abdomen only, suggesting a critical role of atmospheric oxygen in luminescence after death. Although no substantial light signal at the right knee was seen before bone cutting, light emission was evident after cutting. In conclusion, in ex vivo BLI, light emission requires exposure to the atmosphere. Bone destruction is required to demonstrate luciferase activity in the bone marrow after death.

  15. [Atmospheric Polybrominated Diphenyl Ethers in Eight Cities of China: Pollution Characteristics and Human Exposure].

    Science.gov (United States)

    Lin, Hai-tao; Li, Qi-lu; Zhang, Gan; Li, Jun

    2016-01-15

    The gas and particle samples of eight cities were collected by high flow active air sampler in the Eastern and Western China and eight congeners of polybrominated diphenyl ethers were analyzed. The results showed that the concentration of BDE-28 (tri-BDE) in the gas-phase (three bromide components) was the highest, which was different from previous studies where BDE-99 and-47 were the predominant homologues in the gas-phase while the concentration of BDE-209 [(25.4 ± 124) pg · m⁻³] in particle-phase was the highest. The atmospheric concentrations of PBDEs in Beijing and Guangzhou were relatively higher, especially the BDE-209 concentration in particle phases of Guangzhou was two orders higher than those of other cities. However, the atmospheric concentrations of PBDEs declined significantly when compared with the data from previous studies. Meanwhile, the results indicated that the gas-phase concentrations decreased slowly and the particle-phase concentrations decreased rapidly. Combined with the results of correlation analysis, this phenomenon might be ascribed to the ceased commercial production of penta- and octa-BDE, the light degradation of high bromide components and reduced concentrations of atmospheric particles in urban area. Inhalation exposure for infants was about 2-3 times higher than that of adults. This reflected that the potential health risk of atmospheric PBDEs in city for residents, especially infants and young children, should not be ignored.

  16. Atmospheric Dispersion Modelling and Spatial Analysis to Evaluate Population Exposure to Pesticides from Farming Processes

    Directory of Open Access Journals (Sweden)

    Sofia Costanzini

    2018-01-01

    Full Text Available This work originates from an epidemiological study aimed to assess the correlation between population exposure to pesticides used in agriculture and adverse health effects. In support of the population exposure evaluation two models implemented by the authors were applied: a GIS-based proximity model and the CAREA atmospheric dispersion model. In this work, the results of the two models are presented and compared. Despite the proximity analysis is widely used for these kinds of studies, it was investigated how meteorology could affect the exposure assessment. Both models were applied to pesticides emitted by 1519 agricultural fields and considering 2584 receptors distributed over an area of 8430 km2. CAREA output shows a considerable enhancement in the percentage of exposed receptors, from the 4% of the proximity model to the 54% of the CAREA model. Moreover, the spatial analysis of the results on a specific test site showed that the effects of meteorology considered by CAREA led to an anisotropic exposure distribution that differs considerably from the symmetric distribution resulting by the proximity model. In addition, the results of a field campaign for the definition and planning of ground measurement of concentration for the validation of CAREA are presented. The preliminary results showed how, during treatments, pesticide concentrations distant from the fields are significantly higher than background values.

  17. SHORT-TERM EXPOSURE TO ATMOSPHERIC AMMONIA DOES NOT AFFECT LOW-TEMPERATURE HARDENING OF WINTER-WHEAT

    NARCIS (Netherlands)

    CLEMENT, JMAM; VENEMA, JH; VANHASSELT, PR

    1995-01-01

    The effect of atmospheric NH3 on low-temperature hardening of winter wheat (Triticum aestivum L. cv. Urban) was investigated. Growth and photosynthesis were stimulated by ammonia exposure. After a 14 d exposure at moderate temperatures (day/night 18.5/16 degrees C) total nitrogen content was

  18. Comparison of a diurnal vs steady-state ozone exposure profile on growth and yield of oilseed rape (Brassica napus L.) in open-top chambers in the Yangtze Delta, China

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaoke [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqinglu 18, Beijing 100085 (China)], E-mail: wangxk@rcees.ac.cn; Zheng Qiwei; Feng Zhaozhong [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqinglu 18, Beijing 100085 (China); Xie Juqing [Northwestern Sci-Tech University of Agriculture and Forestry, Yangling, Shaanxi 712100 (China); Feng Zongwei; Ouyang Zhiyun [State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqinglu 18, Beijing 100085 (China); Manning, William J. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003-9320 (United States)

    2008-11-15

    Most available exposure-response relationships for assessing crop loss due to elevated ozone (O{sub 3}) have been established using data from chamber and open-top chamber experiments, using a simulated constant O{sub 3} concentration exposure (square wave), which is not consistent with the diurnal variation of O{sub 3} concentration that occurs in nature. We investigated the response of oilseed rape (Brassica napus L.) to O{sub 3} as affected by two exposure regimes: one with a diurnal variation (CF100D) and another with a constant concentration (CF100). Although the two exposure regimes have the same mean O{sub 3} concentration and accumulated O{sub 3} concentration above 40 ppb (AOT40), our results show that O{sub 3} at CF100D reduced biomass and number of pods/plant more than O{sub 3} at CF100. Both O{sub 3} exposures resulted in larger seed weights/100 pods compared to CF. Numbers of seeds/100 pods were reduced by CF100, while numbers of seeds/100 pods in the CF100D chambers were comparable to those in CF. Our results suggest that chamber experiments that use a constant O{sub 3} exposure may underestimate O{sub 3} effects on biomass and yields. - Diurnal variation of O{sub 3} concentration should be considered when designing O{sub 3} exposure experiment.

  19. 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

  20. 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.

  1. High-accuracy and high-sensitivity spectroscopic measurement of dinitrogen pentoxide (N2O5) in an atmospheric simulation chamber using a quantum cascade laser.

    Science.gov (United States)

    Yi, Hongming; Wu, Tao; Lauraguais, Amélie; Semenov, Vladimir; Coeur, Cecile; Cassez, Andy; Fertein, Eric; Gao, Xiaoming; Chen, Weidong

    2017-09-15

    A spectroscopic instrument based on a mid-infrared external cavity quantum cascade laser (EC-QCL) was developed for high-accuracy measurements of dinitrogen pentoxide (N2O5) at the ppbv-level. A specific concentration retrieval algorithm was developed to remove, from the broadband absorption spectrum of N2O5, both etalon fringes resulting from the EC-QCL intrinsic structure and spectral interference lines of H2O vapour absorption, which led to a significant improvement in measurement accuracy and detection sensitivity (by a factor of 10), compared to using a traditional algorithm for gas concentration retrieval. The developed EC-QCL-based N2O5 sensing platform was evaluated by real-time tracking N2O5 concentration in its most important nocturnal tropospheric chemical reaction of NO3 + NO2 ↔ N2O5 in an atmospheric simulation chamber. Based on an optical absorption path-length of Leff = 70 m, a minimum detection limit of 15 ppbv was achieved with a 25 s integration time and it was down to 3 ppbv in 400 s. The equilibrium rate constant Keq involved in the above chemical reaction was determined with direct concentration measurements using the developed EC-QCL sensing platform, which was in good agreement with the theoretical value deduced from a referenced empirical formula under well controlled experimental conditions. The present work demonstrates the potential and the unique advantage of the use of a modern external cavity quantum cascade laser for applications in direct quantitative measurement of broadband absorption of key molecular species involved in chemical kinetic and climate-change related tropospheric chemistry.

  2. Comparative measurements of ambient atmospheric concentrations of ice nucleating particles using multiple immersion freezing methods and a continuous flow diffusion chamber

    Science.gov (United States)

    DeMott, Paul J.; Hill, Thomas C. J.; Petters, Markus D.; Bertram, Allan K.; Tobo, Yutaka; Mason, Ryan H.; Suski, Kaitlyn J.; McCluskey, Christina S.; Levin, Ezra J. T.; Schill, Gregory P.; Boose, Yvonne; Rauker, Anne Marie; Miller, Anna J.; Zaragoza, Jake; Rocci, Katherine; Rothfuss, Nicholas E.; Taylor, Hans P.; Hader, John D.; Chou, Cedric; Huffman, J. Alex; Pöschl, Ulrich; Prenni, Anthony J.; Kreidenweis, Sonia M.

    2017-09-01

    A number of new measurement methods for ice nucleating particles (INPs) have been introduced in recent years, and it is important to address how these methods compare. Laboratory comparisons of instruments sampling major INP types are common, but few comparisons have occurred for ambient aerosol measurements exploring the utility, consistency and complementarity of different methods to cover the large dynamic range of INP concentrations that exists in the atmosphere. In this study, we assess the comparability of four offline immersion freezing measurement methods (Colorado State University ice spectrometer, IS; North Carolina State University cold stage, CS; National Institute for Polar Research Cryogenic Refrigerator Applied to Freezing Test, CRAFT; University of British Columbia micro-orifice uniform deposit impactor-droplet freezing technique, MOUDI-DFT) and an online method (continuous flow diffusion chamber, CFDC) used in a manner deemed to promote/maximize immersion freezing, for the detection of INPs in ambient aerosols at different locations and in different sampling scenarios. We also investigated the comparability of different aerosol collection methods used with offline immersion freezing instruments. Excellent agreement between all methods could be obtained for several cases of co-sampling with perfect temporal overlap. Even for sampling periods that were not fully equivalent, the deviations between atmospheric INP number concentrations measured with different methods were mostly less than 1 order of magnitude. In some cases, however, the deviations were larger and not explicable without sampling and measurement artifacts. Overall, the immersion freezing methods seem to effectively capture INPs that activate as single particles in the modestly supercooled temperature regime (> -20 °C), although more comparisons are needed in this temperature regime that is difficult to access with online methods. Relative to the CFDC method, three immersion freezing

  3. Evaluation of coral pathogen growth rates after exposure to atmospheric African dust samples

    Science.gov (United States)

    Lisle, John T.; Garrison, Virginia H.; Gray, Michael A.

    2014-01-01

    Laboratory experiments were conducted to assess if exposure to atmospheric African dust stimulates or inhibits the growth of four putative bacterial coral pathogens. Atmospheric dust was collected from a dust-source region (Mali, West Africa) and from Saharan Air Layer masses over downwind sites in the Caribbean [Trinidad and Tobago and St. Croix, U.S. Virgin Islands (USVI)]. Extracts of dust samples were used to dose laboratory-grown cultures of four putative coral pathogens: Aurantimonas coralicida (white plague type II), Serratia marcescens (white pox), Vibrio coralliilyticus, and V. shiloi (bacteria-induced bleaching). Growth of A. coralicida and V. shiloi was slightly stimulated by dust extracts from Mali and USVI, respectively, but unaffected by extracts from the other dust sources. Lag time to the start of log-growth phase was significantly shortened for A. coralicida when dosed with dust extracts from Mali and USVI. Growth of S. marcescens and V. coralliilyticus was neither stimulated nor inhibited by any of the dust extracts. This study demonstrates that constituents from atmospheric dust can alter growth of recognized coral disease pathogens under laboratory conditions.

  4. In vitro exposure of human lung cells to emissions of several indoor air sources created in a climate chamber

    NARCIS (Netherlands)

    Bluyssen, P.M.; Alblas, M.J.; Tuinman, I.L.

    2013-01-01

    In the last decade, studies on indoor air pollution suggest a link between exposure to indoor particulate matter and compounds, in particular ultrafine particles and secondary organic aerosols, and several health effects. The mechanisms of how those complex mixtures relate to health effects are

  5. [Particulate matter and atmospheric pollutants exposure for outdoor workers in the Muggia area (Trieste, Italy)].

    Science.gov (United States)

    Urbani, Ranieri; Barbieri, Pierluigi; Cozzutto, Sergio; Barbieri, Gianpiero; Sist, Paola

    2011-01-01

    Urban air pollution originates from traffic, heating and industrial activities and it exposes several categories of workers to noxious chemicals; in recent years various surveys have been carried on taxi drivers, bus drivers, policemen, newspaper kiosks, fuel station workers and general population, for assessing exposure to main contaminants, benzene and PAHs in particular. defining a specific sampling strategy for collecting an experimental data base for the assessment of potential population exposure to atmospheric particulate matter in the Muggia area (Trieste, North-East Italy). A sample of 14 urban police officers working mainly on the roads and potentially subject to occupational exposure has been analyzed, as well as a sample of the municipal administrative personnel (13 people) working in indoor environments during the same sampling periods. Exposure has been monitored by personal samplers and high volume environmental samples; urinary levels of 1 OH-pyrene and creatinine were collected for each participant at the end of each sampling period. PAHs analyses provided diagnostic ratios for identification of the sources of pollution. In general experimental BaP values stay below the environmental target value, with satisfactory agreement between environmental and personal monitoring. Levels of urinary 1 OH-pyrene for administrative personnel was detected always below the background value (0.089 micromoles/mole creatinine), while they are above the background and below the attention value for most of urban police officers. Municipal police officers participating to the present study, while belonging to one of the categories of people most exposed to outdoor PM, do not show any worrying exposure to the considered chemicals associated to their occupational activity, in comparison to other factors, possibly associated to personal lifestyles.

  6. Measuring Leukocyte Adhesion to (Primary Endothelial Cells after Photon and Charged Particle Exposure with a Dedicated Laminar Flow Chamber

    Directory of Open Access Journals (Sweden)

    Nadine Erbeldinger

    2017-06-01

    Full Text Available The vascular endothelium interacts with all types of blood cells and is a key modulator of local and systemic inflammatory processes, for example, in the adhesion of blood leukocytes to endothelial cells (EC and the following extravasation into the injured tissue. The endothelium is constantly exposed to mechanical forces caused by blood flow, and the resulting shear stress is essential for the maintenance of endothelial function. Changes in local hemodynamics are sensed by EC, leading to acute or persistent changes. Therefore, in vitro assessment of EC functionality should include shear stress as an essential parameter. Parallel-plate flow chambers with adjustable shear stress can be used to study EC properties. However, commercially available systems are not suitable for radiation experiments, especially with charged particles, which are increasingly used in radiotherapy of tumors. Therefore, research on charged-particle-induced vascular side effects is needed. In addition, α-particle emitters (e.g., radon are used to treat inflammatory diseases at low doses. In the present study, we established a flow chamber system, applicable for the investigation of radiation induced changes in the adhesion of lymphocytes to EC as readout for the onset of an inflammatory reaction or the modification of a pre-existing inflammatory state. In this system, primary human EC are cultured under physiological laminar shear stress, subjected to a proinflammatory treatment and/or irradiation with X-rays or charged particles, followed by a coincubation with primary human lymphocytes (peripheral blood lymphocytes (PBL. Analysis is performed by semiautomated quantification of fluorescent staining in microscopic pictures. First results obtained after irradiation with X-rays or helium ions indicate decreased adhesion of PBL to EC under laminar conditions for both radiation qualities, whereas adhesion of PBL under static conditions is not clearly affected by irradiation

  7. 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.

  8. 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.

  9. Dataset of Atmospheric Environment Publication in 2016, Source emission and model evaluation of formaldehyde from composite and solid wood furniture in a full-scale chamber

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data presented in this data file is a product of a journal publication. The dataset contains formaldehyde air concentrations in the emission test chamber and...

  10. Investigation of Heterogeneous Atmospheric Chlorine Chemistry: Modeling and Environmental Chamber Studies Authors: Cameron B. Faxon, Lea Hildebrandt Ruiz, and David Allen University of Texas at Austin, McKetta Department of Chemical Engineering

    Science.gov (United States)

    Faxon, C. B.; Hildebrandt Ruiz, L.; Allen, D.

    2013-12-01

    Previous work has shown that gas phase atomic chlorine radicals (Cl*) can influence tropospheric photochemistry, including concentrations of volatile organic compound (VOC) and ozone. These radicals are produced through both gas phase and heterogeneous pathways. This work presents computational and experimental investigation into the heterogeneous reactions of chloride aerosols. An overview of a sensitivity analysis of the physical parameters involved in the heterogeneous production of nitryl chloride (ClNO2) (R1-R5) will comprise the computational work presented. NO2(g) + NO3(g) ↔ N2O5(g) (R1) N2O5(aq) ↔ N2O5(aq) (R2) N2O5(aq) ↔ NO2+(aq) + NO3-(aq) (R3) NO2+(aq) + H2O(aq) → H3O+(aq) + HNO3(aq) (R4a) NO2+(aq) + Cl- → ClNO2 + H2O(aq) (R4b) NO3-(aq) + H+ ↔ HNO3+(aq) (R5) Relative parameters include the reactive uptake coefficient, ClNO2 yield, particle surface area, and gas phase concentrations of VOCs and NOx. The sensitivity analysis results were generated through photochemical box modeling and focus on the production of ClNO2 and impacts to ozone production. Results were compared to a base case scenario in which all heterogeneous reactions were absent. Parameter values reaching the upper limits reported in the literature were tested, and results indicate that ClNO2 chemistry can potentially change peak O3 concentrations by -10.5% to 27%. NOx availability was also found to play an important role. Experimental results of the heterogeneous reaction between OH* and particulate chloride (R6-R7) will also be discussed. The mechanism is shown below, and OH***Cl- represents an intermediate species forming at the particle surface. OH(g) + Cl-(aq) → OH***Cl-(aq) (R6) 2OH***Cl-(aq) → Cl2,g + 2OH-(aq) (R7) Environmental chamber experiments involving the exposure of NaCl aerosol particles to typical atmospheric conditions (HOx, NOx, O3 and UV radiation) were performed. A 10 cubic meter teflon reaction chamber equipped with UV lights was used to contain the

  11. Whole-body new-born and young rats' exposure assessment in a reverberating chamber operating at 2.4 GHz

    Science.gov (United States)

    Wu, Tongning; Hadjem, Abdelhamid; Wong, Man-Fai; Gati, Azzedine; Picon, Odile; Wiart, Joe

    2010-03-01

    This paper presents the whole-body specific absorption rate (WBSAR) assessment of embryos and new-born rats' exposure in a reverberating chamber (RC) operating at 2.4 GHz (WiFi). The finite difference in time domain (FDTD) method often used in bio-electromagnetism is facing very slow convergence. A new simulation-measurement hybrid approach has been proposed to characterize the incident power related to the RC and the WBSAR in rats, which are linked by the mean squared electric field strength in the working volume. Peak localized SAR in the rat under exposure is not included in the content of the study. Detailed parameters of this approach are determined by simulations. Evolutions for the physical and physiological parameters of the small rats at different ages are discussed. Simulations have been made to analyse all the variability factors contributing to the global results. WBSAR information and the variability for rats at different ages are also discussed in the paper.

  12. Embryonic Ethanol Exposure Affects Early- and Late-Added Cardiac Precursors and Produces Long-Lasting Heart Chamber Defects in Zebrafish

    Directory of Open Access Journals (Sweden)

    Swapnalee Sarmah

    2017-12-01

    Full Text Available Drinking mothers expose their fetuses to ethanol, which produces birth defects: craniofacial defects, cognitive impairment, sensorimotor disabilities and organ deformities, collectively termed as fetal alcohol spectrum disorder (FASD. Various congenital heart defects (CHDs are present in FASD patients, but the mechanisms of alcohol-induced cardiogenesis defects are not completely understood. This study utilized zebrafish embryos and older larvae to understand FASD-associated CHDs. Ethanol-induced cardiac chamber defects initiated during embryonic cardiogenesis persisted in later zebrafish life. In addition, myocardial damage was recognizable in the ventricle of the larvae that were exposed to ethanol during embryogenesis. Our studies of the pathogenesis revealed that ethanol exposure delayed differentiation of first and second heart fields and reduced the number of early- and late-added cardiomyocytes in the heart. Ethanol exposure also reduced the number of endocardial cells. Together, this study showed that ethanol-induced heart defects were present in late-stage zebrafish larvae. Reduced numbers of cardiomyocytes partly accounts for the ethanol-induced zebrafish heart defects.

  13. Embryonic Ethanol Exposure Affects Early- and Late-Added Cardiac Precursors and Produces Long-Lasting Heart Chamber Defects in Zebrafish.

    Science.gov (United States)

    Sarmah, Swapnalee; Marrs, James A

    2017-12-01

    Drinking mothers expose their fetuses to ethanol, which produces birth defects: craniofacial defects, cognitive impairment, sensorimotor disabilities and organ deformities, collectively termed as fetal alcohol spectrum disorder (FASD). Various congenital heart defects (CHDs) are present in FASD patients, but the mechanisms of alcohol-induced cardiogenesis defects are not completely understood. This study utilized zebrafish embryos and older larvae to understand FASD-associated CHDs. Ethanol-induced cardiac chamber defects initiated during embryonic cardiogenesis persisted in later zebrafish life. In addition, myocardial damage was recognizable in the ventricle of the larvae that were exposed to ethanol during embryogenesis. Our studies of the pathogenesis revealed that ethanol exposure delayed differentiation of first and second heart fields and reduced the number of early- and late-added cardiomyocytes in the heart. Ethanol exposure also reduced the number of endocardial cells. Together, this study showed that ethanol-induced heart defects were present in late-stage zebrafish larvae. Reduced numbers of cardiomyocytes partly accounts for the ethanol-induced zebrafish heart defects.

  14. Whole-body new-born and young rats' exposure assessment in a reverberating chamber operating at 2.4 GHz.

    Science.gov (United States)

    Wu, Tongning; Hadjem, Abdelhamid; Wong, Man-Fai; Gati, Azzedine; Picon, Odile; Wiart, Joe

    2010-03-21

    This paper presents the whole-body specific absorption rate (WBSAR) assessment of embryos and new-born rats' exposure in a reverberating chamber (RC) operating at 2.4 GHz (WiFi). The finite difference in time domain (FDTD) method often used in bio-electromagnetism is facing very slow convergence. A new simulation-measurement hybrid approach has been proposed to characterize the incident power related to the RC and the WBSAR in rats, which are linked by the mean squared electric field strength in the working volume. Peak localized SAR in the rat under exposure is not included in the content of the study. Detailed parameters of this approach are determined by simulations. Evolutions for the physical and physiological parameters of the small rats at different ages are discussed. Simulations have been made to analyse all the variability factors contributing to the global results. WBSAR information and the variability for rats at different ages are also discussed in the paper.

  15. Augmented survival of Neisseria gonorrhoeae within biofilms: exposure to atmospheric pressure non-thermal plasmas.

    Science.gov (United States)

    Xu, L; Tu, Y; Yu, Y; Tan, M; Li, J; Chen, H

    2011-01-01

    Bacteria embedded within biofilms present a challenge to surface decontamination by conventional means. Atmospheric pressure non-thermal plasma processes have emerged as a promising approach to overcoming this problem. We used atmospheric pressure non-equilibrium plasmas (APNPs) to assess planktonic versus biofilm-resident bacterial (Neisseria gonorrhoeae) susceptibility to treatment. The decontamination efficiency of the process was evaluated against bacteria embedded within a biofilm, as well as planktonic cells placed on a glass surface. Bacterial survival was assessed using a combination of colony forming unit (CFU) ability and vital staining with a combination of SYTO9 plus propidium iodide. Both methods revealed an increased resistance of biofilm-resident bacteria compared with planktonic cells, after a 20-min exposure to the APNPs. Transmission electron microscopy revealed disruption and damage to the cell wall, resulting in the release of cytoplasmic compounds, alterations in morphology, and a decrease in cell volume, indicating that APNPs may affect the cell wall. Present results show that biofilm-resident bacteria demonstrate augmented survival when exposed to APNP treatment and therefore that decontamination procedures should take into account this survival when evaluating surface decontamination measures.

  16. Yttrium and lanthanides in human lung fluids, probing the exposure to atmospheric fallout

    Energy Technology Data Exchange (ETDEWEB)

    Censi, P., E-mail: censi@unipa.it [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy); I.A.M.C.-CNR - UOS di Capo Granitola, Via faro, 1 - 91026 Torretta Granitola, Campobello di Mazara (TP) (Italy); En.Bio.Tech. - Via Aquileia, 35 90100 Palermo (Italy); Tamburo, E. [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy); Speziale, S. [Deutsches GeoForschungsZentrum, Telegrafenberg, Potsdam, 14473 (Germany); Zuddas, P. [Institut Genie de l' Environnement et Ecodeveloppement and Departement Sciences de la Terre, UMR 5125, Universite Claude Bernard Lyon 1, 2 rue R. Dubois, Bat GEODE 69622 Villeurbanne Cedex (France); Randazzo, L.A. [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy); I.A.M.C.-CNR - UOS di Capo Granitola, Via faro, 1 - 91026 Torretta Granitola, Campobello di Mazara (TP) (Italy); En.Bio.Tech. - Via Aquileia, 35 90100 Palermo (Italy); Institut Genie de l' Environnement et Ecodeveloppement and Departement Sciences de la Terre, UMR 5125, Universite Claude Bernard Lyon 1, 2 rue R. Dubois, Bat GEODE 69622 Villeurbanne Cedex (France); Punturo, R. [Dipartimento di Scienze Geologiche, Universita di Catania, Corso Italia, 55 - 95129 Catania (Italy); Cuttitta, A. [I.A.M.C.-CNR - UOS di Capo Granitola, Via faro, 1 - 91026 Torretta Granitola, Campobello di Mazara (TP) (Italy); Arico, P. [Dipartimento C.F.T.A., Universita di Palermo, Via Archirafi, 36 90123 - Palermo (Italy)

    2011-02-28

    Inhalation of airborne particles can produce crystallization of phosphatic microcrysts in intraaveolar areas of lungs, sometimes degenerating into pulmonary fibrosis. Results of this study indicate that these pathologies are induced by interactions between lung fluids and inhaled atmospheric dust in people exposed to volcanic dust ejected from Mount Etna in 2001. Here, the lung solid-liquid interaction is evaluated by the distribution of yttrium and lanthanides (YLn) in fluid bronchoalveolar lavages on selected individuals according the classical geochemical approaches. We found that shale-normalised patterns of yttrium and lanthanides have a 'V shaped' feature corresponding to the depletion of elements from Nd to Tb when compared to the variable enrichments of heavy lanthanides, Y, La and Ce. These features and concurrent thermodynamic simulations suggest that phosphate precipitation can occur in lungs due to interactions between volcanic particles and fluids. We propose that patterns of yttrium and lanthanides can represent a viable explanation of some pathology observed in patients after prolonged exposure to atmospheric fallout and are suitable to become a diagnostic parameter of chemical environmental stresses.

  17. Atmospheric PSF Interpolation for Weak Lensing in Short Exposure Imaging Data

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.; Marshall, P.J.; Jernigan, J.G.; Peterson, J.R.; Kahn, S.M.; Gull, S.F.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, S.; Meert, A.

    2012-09-19

    A main science goal for the Large Synoptic Survey Telescope (LSST) is to measure the cosmic shear signal from weak lensing to extreme accuracy. One difficulty, however, is that with the short exposure time ({approx_equal}15 seconds) proposed, the spatial variation of the Point Spread Function (PSF) shapes may be dominated by the atmosphere, in addition to optics errors. While optics errors mainly cause the PSF to vary on angular scales similar or larger than a single CCD sensor, the atmosphere generates stochastic structures on a wide range of angular scales. It thus becomes a challenge to infer the multi-scale, complex atmospheric PSF patterns by interpolating the sparsely sampled stars in the field. In this paper we present a new method, psfent, for interpolating the PSF shape parameters, based on reconstructing underlying shape parameter maps with a multi-scale maximum entropy algorithm. We demonstrate, using images from the LSST Photon Simulator, the performance of our approach relative to a 5th-order polynomial fit (representing the current standard) and a simple boxcar smoothing technique. Quantitatively, psfent predicts more accurate PSF models in all scenarios and the residual PSF errors are spatially less correlated. This improvement in PSF interpolation leads to a factor of 3.5 lower systematic errors in the shear power spectrum on scales smaller than {approx} 13, compared to polynomial fitting. We estimate that with psfent and for stellar densities greater than {approx_equal}1/arcmin{sup 2}, the spurious shear correlation from PSF interpolation, after combining a complete 10-year dataset from LSST, is lower than the corresponding statistical uncertainties on the cosmic shear power spectrum, even under a conservative scenario.

  18. An overview of organically bound tritium experiments in plants following a short atmospheric HTO exposure.

    Science.gov (United States)

    Galeriu, D; Melintescu, A; Strack, S; Atarashi-Andoh, M; Kim, S B

    2013-04-01

    The need for a less conservative, but reliable risk assessment of accidental tritium releases is emphasized in the present debate on the nuclear energy future. The development of a standard conceptual model for accidental tritium releases must be based on the process level analysis and the appropriate experimental database. Tritium transfer from atmosphere to plants and the subsequent conversion into organically bound tritium (OBT) strongly depends on the plant characteristics, seasons, and meteorological conditions, which have a large variability. The present study presents an overview of the relevant experimental data for the short term exposure, including the unpublished information, also. Plenty of experimental data is provided for wheat, rice, and soybean and some for potato, bean, cherry tomato, radish, cabbage, and tangerine as well. Tritiated water (HTO) uptake by plants during the daytime and nighttime has an important role in further OBT synthesis. OBT formation in crops depends on the development stage, length, and condition of exposure. OBT translocation to the edible plant parts differs between the crops analyzed. OBT formation during the nighttime is comparable with that during the daytime. The present study is a preliminary step for the development of a robust model of crop contamination after an HTO accidental release. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Children exposure to atmospheric particles in indoor of Lisbon primary schools

    Science.gov (United States)

    Almeida, Susana Marta; Canha, Nuno; Silva, Ana; Freitas, Maria do Carmo; Pegas, Priscilla; Alves, Célia; Evtyugina, Margarita; Pio, Casimiro Adrião

    2011-12-01

    Evidence continues to emerge showing that poor Indoor Air Quality (IAQ) can cause illness requiring absence from schools, and can cause acute health symptoms that decrease students' performance. Since children spend on average 7-11 h per weekday at school, the IAQ in classrooms is expected to play a key role in the assessment of the effects of their personal exposure to air pollution. Within this context the present study was conducted in order to fulfill three primary objectives 1) to measure the levels and the element composition of PM 2.5 and PM 2.5-10, in three primary schools placed in Lisbon, in order to assess the children exposure to these pollutants; 2) to study the relationship between indoor and outdoor atmospheric particles concentrations and 3) to investigate the sources of high aerosols concentrations in classrooms. In the studied classrooms, the concentrations of coarse particles significantly exceeded the ambient levels. Element concentrations suggested that the physical activity of students highly contributed to the re-suspension of sedimented particles. The high levels of CO 2 indicated that in these schools the ventilation was inadequate. This fact contributed to the establishment of poor IAQ.

  20. Forecasting human exposure to atmospheric pollutants in Portugal - A modelling approach

    Science.gov (United States)

    Borrego, C.; Sá, E.; Monteiro, A.; Ferreira, J.; Miranda, A. I.

    2009-12-01

    Air pollution has become one main environmental concern because of its known impact on human health. Aiming to inform the population about the air they are breathing, several air quality modelling systems have been developed and tested allowing the assessment and forecast of air pollution ambient levels in many countries. However, every day, an individual is exposed to different concentrations of atmospheric pollutants as he/she moves from and to different outdoor and indoor places (the so-called microenvironments). Therefore, a more efficient way to prevent the population from the health risks caused by air pollution should be based on exposure rather than air concentrations estimations. The objective of the present study is to develop a methodology to forecast the human exposure of the Portuguese population based on the air quality forecasting system available and validated for Portugal since 2005. Besides that, a long-term evaluation of human exposure estimates aims to be obtained using one-year of this forecasting system application. Additionally, a hypothetical 50% emission reduction scenario has been designed and studied as a contribution to study emission reduction strategies impact on human exposure. To estimate the population exposure the forecasting results of the air quality modelling system MM5-CHIMERE have been combined with the population spatial distribution over Portugal and their time-activity patterns, i.e. the fraction of the day time spent in specific indoor and outdoor places. The population characterization concerning age, work, type of occupation and related time spent was obtained from national census and available enquiries performed by the National Institute of Statistics. A daily exposure estimation module has been developed gathering all these data and considering empirical indoor/outdoor relations from literature to calculate the indoor concentrations in each one of the microenvironments considered, namely home, office/school, and other

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Health effects from exposure to atmospheric mineral dust near Las Vegas, NV, USA

    Directory of Open Access Journals (Sweden)

    Deborah E. Keil

    2016-01-01

    Full Text Available Desert areas are usually characterized by a continuous deposition of fine airborne particles. Over time, this process results in the accumulation of silt and clay on desert surfaces. We evaluated health effects associated with regional atmospheric dust, or geogenic dust, deposited on surfaces in the Nellis Dunes Recreation Area (NDRA in Clark County, Nevada, a popular off-road vehicle (ORV recreational site frequented daily by riders, families, and day campers. Because of atmospheric mixing and the mostly regional origin of the accumulated particles, the re-suspended airborne dust is composed of a complex mixture of minerals and metals including aluminum, vanadium, chromium, manganese, iron, cobalt, copper, zinc, arsenic, strontium, cesium, lead, uranium, and others. Geogenic dust with a median diameter of 4.1 μm was administered via oropharyngeal aspiration to female B6C3F1 mice at doses of 0.01 to 100 mg dust/kg body weight, four times, a week apart, for 28-days. Immuno- and neurotoxicological outcomes 24 h following the last exposure were evaluated. Antigen-specific IgM responses were dose-responsively suppressed at 0.1, 1.0, 10 and 100 mg/kg/day. Splenic and thymic lymphocytic subpopulations and natural killer cell activity also were significantly reduced. Antibodies against MBP, NF-68, and GFAP were not affected, while brain CD3+ T cells were decreased in number. A lowest observed adverse effect level (LOAEL of 0.1 mg/kg/day and a no observed adverse effect level (NOAEL of 0.01 mg/kg/day were derived based on the antigen-specific IgM responses.

  6. Short-term exposure to atmospheric ammonia does not affect frost hardening of needles from three- and five-year-old Scots pine trees

    NARCIS (Netherlands)

    Clement, J.M A M; van Hasselt, P.R; van Eerden, L.J.M.; Dueck, T.A.

    The effect of atmospheric ammonia on frost hardening of needles from 3- and 5-year-old Scots pine trees was investigated. Trees were exposed to various concentrations of NH(3) during different hardening stages under laboratory conditions and in experiments with open-top chambers under a natural

  7. Comprehensive default methodology for the analysis of exposures to mixtures of chemicals accidentally released to the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Craig, D.K. [Westinghouse Savannah River Company, Aiken, SC (United States); Baskett, R.L.; Powell, T.J. [Lawrence Livermore National Lab., CA (United States); Davis, J.S. [Duke Engineering Services, Hanford, Inc., Charlotte, NC (United States); Dukes, L.L. [Automated Solutions of Albuquerque, NM (United States); Hansen, D.J. [Brookhaven National Lab., Upton, NY (United States); Petrocchi, A.J. [AlphaTRAC, Inc. (United States); Sutherland, P.J. [Battelle Memorial Institute, Columbus, OH (United States)

    1997-07-01

    Safety analysis of Department of Energy (DOE) facilities requires consideration of potential exposures to mixtures of chemicals released to the atmosphere. Exposure to chemical mixtures may lead to additive, synergistic, or antagonistic health effects. In the past, the consequences of each chemical have been analyzed separately. This approach may not adequately protect the health of persons exposed to mixtures. However, considerable time would be required to evaluate all possible mixtures. The objective of this paper is to present reasonable default methodology developed by the EFCOG Safety Analysis Working Group Nonradiological Hazardous Material Subgroup (NHMS) for use in safety analysis within the DOE Complex.

  8. Emulsion Chamber Technology Experiment (ECT)

    Science.gov (United States)

    Gregory, John C.; Takahashi, Yoshiyuki

    1996-01-01

    The experimental objective of Emulsion Chamber Technology (ECT) was to develop space-borne emulsion chamber technology so that cosmic rays and nuclear interactions may subsequently be studied at extremely high energies with long exposures in space. A small emulsion chamber was built and flown on flight STS-62 of the Columbia in March 1994. Analysis of the several hundred layers of radiation-sensitive material has shown excellent post-flight condition and suitability for cosmic ray physics analysis at much longer exposures. Temperature control of the stack was 20 +/-1 C throughout the active control period and no significant deviations of temperature or pressure in the chamber were observed over the entire mission operations period. The unfortunate flight attitude of the orbiter (almost 90% Earth viewing) prevented any significant number of heavy particles (Z greater than or equal to 10) reaching the stack and the inverted flow of shower particles in the calorimeter has not allowed evaluation of absolute primary cosmic ray-detection efficiency nor of the practical time limits of useful exposure of these calorimeters in space to the level of detail originally planned. Nevertheless, analysis of the observed backgrounds and quality of the processed photographic and plastic materials after the flight show that productive exposures of emulsion chambers are feasible in low orbit for periods of up to one year or longer. The engineering approaches taken in the ECT program were proven effective and no major environmental obstacles to prolonged flight are evident.

  9. Use of molecular beacons for the rapid analysis of DNA damage induced by exposure to an atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Hirofumi, E-mail: kurita@ens.tut.ac.jp, E-mail: mizuno@ens.tut.ac.jp; Miyachika, Saki; Yasuda, Hachiro; Takashima, Kazunori; Mizuno, Akira, E-mail: kurita@ens.tut.ac.jp, E-mail: mizuno@ens.tut.ac.jp [Department of Environmental and Life Sciences, Toyohashi University of Technology, Aichi 441-8580 (Japan)

    2015-12-28

    A rapid method for evaluating the damage caused to DNA molecules upon exposure to plasma is demonstrated. Here, we propose the use of a molecular beacon for rapid detection of DNA strand breaks induced by atmospheric pressure plasma jet (APPJ) irradiation. Scission of the molecular beacon by APPJ irradiation leads to separation of the fluorophore-quencher pair, resulting in an increase in fluorescence that directly correlates with the DNA strand breaks. The results show that the increase in fluorescence intensity is proportional to the exposure time and the rate of fluorescence increase is proportional to the discharge power. This simple and rapid method allows the estimation of DNA damage induced by exposure to a non-thermal plasma.

  10. 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.

  11. A Micro-fabricated Hydrogen Storage Module with Sub-atmospheric Activation and Durability in Air Exposure.

    Science.gov (United States)

    Shan, Xi; Payer, Joe H; Wainright, Jesse S; Dudik, Laurie

    2011-01-15

    The objective of this work was to develop a hydrogen storage module for onboard electrical power sources suitable for use in micro power systems and micro-electro-mechanical systems (MEMS). Hydrogen storage materials were developed as thin-film inks to be compatible with an integrated manufacturing process. Important design aspects were (a) ready activation at sub-atmospheric hydrogen pressure and room temperature and (b) durability, i.e. capable of hundreds of absorption/desorption cycles and resistance to deactivation on exposure to air. Inks with palladium-treated intermetallic hydrogen storage alloys were developed and are shown here to be compatible with a thin-film micro-fabrication process. These hydrogen storage modules absorb hydrogen readily at atmospheric pressure, and the absorption/desorption rates remained fast even after the ink was exposed to air for 47 weeks.

  12. AXAIR: A Computer Code for SAR Assessment of Plume-Exposure Doses from Potential Process-Accident Releases to Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Pillinger, W.L.

    2001-05-17

    This report describes the AXAIR computer code which is available to terminal users for evaluating the doses to man from exposure to the atmospheric plume from postulated stack or building-vent releases at the Savannah River Plant. The emphasis herein is on documentation of the methodology only. The total-body doses evaluated are those that would be exceeded only 0.5 percent of the time based on worst-sector, worst-case meteorological probability analysis. The associated doses to other body organs are given in the dose breakdowns by radionuclide, body organ and pathway.

  13. Blood gas-analyses in patients with cystic fibrosis to estimate hypoxemia during exposure to high altitudes in a hypobaric-chamber.

    Science.gov (United States)

    Rose, D M; Fleck, B; Thews, O; Kamin, W E

    2000-01-26

    Patients with cystic fibrosis (CF) represent a special risk for commercial airlines. Even on ground conditions the oxygen partial pressure (paO subset2) of these patients is partially clearly reduced. The reduced air pressure on board of an airplane can cause a drop of the paO subset2 to a critical point (below 50 mmHg) during a flight. Therefore, medical assistance or at least oxygen-supply over a longer time period could be necessary. Aim of this study was to investigate reaction and clinical outcome of patients with CF during a hypobaric-chamber-flight at altitudes of 2. 000 and 3.000 m to appraise their risk for a flight-trip. 10 CF-patients (age 19-35 years, mean age 30 y) were investigated in a hypobaric chamber prior to an already booked flight-trip to the Baleares (Spain). Lung-function, oxygen saturation (SO subset2) and paO subset2 by pressure adjusted blood gas analysis were measured on ground level, at 2.000 m and 3.000 m pressure-altitude. Forced expiratory vital capacity (FVC) over the entire group was 2. 9 l (range 1.4 to 4.0 l), forced expiratory 1-second volume (FEV subset1) 2.08 l/sec (range: 1.22 to 3.61 l/sec). Values dropped slightly at 3.000 m chamber altitude (VC=2.7 l, FEV subset1=1.95 l/sec). SO subset2 decreased from 95 % on ground to 89% at 2.000 m and 86 % at 3.000 m chamber altitude. paO2 decreased from 79.5 mmHg at ground level to 60 mmHg at 2000m and 45.5 mmHg at 3.000 m. Only one patient with a paO subset2 of 52 mmHg didn t fall below the critical flight limit of 50 mmHg. No patient felt below a paO subset2 of 40 mmHg. No patient experienced dyspnea during the chamber flight. Two patients without subjective symptoms before the chamber flight developed mild ear blocks during descent presumably due to swollen polyps. Complaints improved quickly by applying decongestant nose-spray. - The results of the chamber flights indicate that chronically adapted adult lung disease patients without accompanying heart disease and a paO subset2 of

  14. RF Anechoic Chambers, Tri-Service Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — In collaboration with the Navy, there are 12 RF Anechoic and static free exposure chambers located at TSRL. These chambers cover the majority of the RF spectrum and...

  15. 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...

  16. Improved conductivity of ZnO thin films by exposure to an atmospheric hydrogen plasma

    NARCIS (Netherlands)

    Illiberi, A.; Kniknie, B.; Deelen, J. van; Steijvers, H.L.A.H.; Habets, D.; Simons, P.J.P.M.; Janssen, A.C.; Beckers, E.H.A.

    2012-01-01

    Aluminum-doped zinc oxide (ZnOx:Al) films have been deposited on a moving glass substrate by a high throughput metalorganic chemical vapor deposition process at atmospheric pressure. Thin (< 250 nm) ZnOx:Al films have a poor crystalline quality, due to a small grain size and the presence of

  17. 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...

  18. "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.

  19. Test of an undulated vacuum chamber for the ISR

    CERN Multimedia

    1975-01-01

    This picture shows mechanical tests of an undulated vacuum chamber for downstream arms of ISR intersections. This chamber, made of 0.3 mm thick inconel, had inner dimensions of 150 mm by 50 mm. The deflection under vacuum is measured by dial gauges. On the left one sees the large vessel where vacuum chambers were tested at pressures above atmospheric pressure.

  20. [Assessment of a risk from exposure to atmosphere bus industrial emissions].

    Science.gov (United States)

    Stepkin, Iu I; Kuzmichev, M K

    2009-01-01

    The carcinogenic and noncarcinogenic risks to health were estimated in accordance with the requirements stated in the guide P 2.1.10.1920-04 "Guidelines for assessing the health risk in the population exposed to the chemicals polluting the environment" (approved by G. G. Onishchenko, state sanitary inspector on March 5, 2004) and comprised four successive steps: 1) identification of a hazard; 2) estimation of a dose-response relationship; 3) evaluation of exposure of the population to chemical substances; 4) characterization of a risk, by calculating the individual carcinogenic risk, hazard coefficients and indices characterizing the noncarcinogenic risk. The performed assessment of the health risk to the population living in the area exposed to the ambient air pollutant emissions by the AOA "Shinnyi Kompleks Amtel-Chenozymye" (Amtel-Chernozem Tyre Complex) allowed determination of priority pollutants, by taking into account their effect on human health. The individual carcinogenic risk to health has been found to be higher than the acceptable (safe) level (10-4) was due to the probable exposure to a 2-heptane fraction (nefras ChS 94/99) and hexavalent chromium. The highest non-carcinogenic risk to human was also due to the heptane fraction (nefras ChS 94/99) (hazard coefficient > 1).

  1. Oxidative modification and electrochemical inactivation of Escherichia coli upon cold atmospheric pressure plasma exposure.

    Directory of Open Access Journals (Sweden)

    Marlène Dezest

    Full Text Available Cold atmospheric pressure plasmas (CAPPs are known to have bactericidal effects but the mechanism of their interaction with microorganisms remains poorly understood. In this study the bacteria Escherichia coli were used as a model and were exposed to CAPPs. Different gas compositions, helium with or without adjunctions of nitrogen or oxygen, were used. Our results indicated that CAPP induced bacterial death at decontamination levels depend on the duration, post-treatment storage and the gas mixture composition used for the treatment. The plasma containing O2 in the feeding gas was the most aggressive and showed faster bactericidal effects. Structural modifications of treated bacteria were observed, especially significant was membrane leakage and morphological changes. Oxidative stress caused by plasma treatment led to significant damage of E. coli. Biochemical analyses of bacterial macromolecules indicated massive intracellular protein oxidation. However, reactive oxygen and nitrogen species (RONS are not the only actors involved in E. coli's death, electrical field and charged particles could play a significant role especially for He-O2 CAPP.

  2. Impacts of Mercury Pollution Controls on Atmospheric Mercury Concentration and Occupational Mercury Exposure in a Hospital.

    Science.gov (United States)

    Li, Ping; Yang, Yan; Xiong, Wuyan

    2015-12-01

    Mercury (Hg) and Hg-containing products are used in a wide range of settings in hospitals. Hg pollution control measures were carried out in the pediatric ward of a hospital to decrease the possibility of Hg pollution occurring and to decrease occupational Hg exposure. Total gaseous Hg (TGM) concentrations in the pediatric ward and hair and urine Hg concentrations for the pediatric staff were determined before and after the Hg pollution control measures had been implemented. A questionnaire survey performed indicated that the pediatric staff had little understanding of Hg pollution and that appropriate disposal techniques were not always used after Hg leakage. TGM concentrations in the pediatric ward and urine Hg (UHg) concentrations for the pediatric staff were 25.7 and 22.2% lower, respectively, after the Hg pollution control measures had been implemented than before, which indicated that the control measures were effective. However, TGM concentrations in the pediatric ward remained significantly higher than background concentrations and UHg concentrations for the pediatric staff were remained significantly higher than the concentrations in control group, indicating continued existence of certain Hg pollution.

  3. Exposure of volunteers to a radon progeny enriched atmosphere; Exposition von freiwilligen Probanden in einer an Radonzerfallsprodukten angereicherten Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Butterweck-Dempewolf, G.; Schuler, C.; Vezzu, G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1998-12-31

    For an improvement of dose estimation of the exposure by inhalation of radon progeny in the domestic environment human volunteers were exposed to precisely determined radon progeny atomospheres in the walk-in radon chamber at the Paul Scherrer Institut (PSI). One of the major targets of the experiments consists of the determination of the transport rate of the short-lived radon progeny from the respiratory tract into the blood circuit. The question is, if this transport may be fast enough compared to the physical half-life of the radon progeny to have a significant influence on dose considerations. The experimental set-up consisting of measurement devices for the size distribution of the unattached radon progeny during the exposure and for the activity of the radon progeny in the blood circuit is described. First volunteers have been exposed to atomspheres with a large fraction of unattached radon progeny. From these measurements, a larger transfer rate of the unattached radon progeny from respiratory tract to the blood circuit than reported in the literature can be derived, but without reaching values significantly influencing dose estimations. (orig.) [Deutsch] Mit dem Ziel, die Inhalationsdosis der Radonzerfallsprodukte im haeuslichen Umfeld besser abschaetzen zu koennen, wurden freiwillige Probanden in der begehbaren Radonkammer des Paul Scherrer Instituts (PSI) einer sehr genau bekannten Radonzerfallsproduktsatmosphaere ausgesetzt. Eines der Hauptziele dieser Experimente betrifft den Transport der kurzlebigen Radonzerfallsprodukte vom Atmungstrakt in den Blutkreislauf. Beantwortet werden soll die Frage, ob dieser Transport verglichen mit der physikalischen Halbwertzeit dieser Nuklide schnell genug sein koennte, um einen dosisrelevanten Einfluss zu haben. Der experimentelle Aufbau, bestehend aus Apparaturen fuer die Messung der Groessenverteilung des unangelagerten Anteils der Radonzerfallsprodukte waehrend der Expositionen und der Aktivitaet im Blutkreislauf

  4. Visible leaf injury in young trees of Fagus sylvatica L. and Quercus robur L. in relation to ozone uptake and ozone exposure. An Open-Top Chambers experiment in South Alpine environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gerosa, G. [Catholic University of Brescia, Department of Mathematics and Physics, Via dei Musei 41, 25125 Brescia (Italy); Marzuoli, R. [Catholic University of Brescia, Department of Mathematics and Physics, Via dei Musei 41, 25125 Brescia (Italy)], E-mail: riccardo.marzuoli@unicatt.it; Desotgiu, R.; Bussotti, F. [University of Florence, Department of Plant Biology, Piazzale delle Cascine 28, 50144 Florence (Italy); Ballarin-Denti, A. [Catholic University of Brescia, Department of Mathematics and Physics, Via dei Musei 41, 25125 Brescia (Italy)

    2008-03-15

    An Open-Top Chambers experiment on Fagus sylvatica and Quercus robur seedlings was conducted in order to compare the performance of an exposure-based (AOT40) and a flux-based approaches in predicting the appearance of ozone visible injuries on leaves. Three different ozone treatments (charcoal-filtered; non-filtered; and open plots) and two soil moisture treatments (watered and non-watered plots) were performed. A Jarvisian stomatal conductance model was drawn up and parameterised for both species and typical South Alpine environmental conditions, thus allowing the calculation of ozone stomatal fluxes for every treatment. A critical ozone flux level for the onset of leaf visible injury in beech was clearly identified between 32.6 and 33.6 mmol O{sub 3}m{sup -2}. In contrast, it was not possible to identify an exposure critical level using the AOT40 index. Water stress delayed the onset of the leaf visible injuries, but the flux-based approach was able to take it into account accurately. - Ozone fluxes are more accurate than AOT40 exposure index in predicting ozone visible foliar injury onset on beech seedlings in South Alpine environmental conditions.

  5. Fungal community composition and function after long-term exposure of northern forests to elevated atmospheric CO2 and tropospheric O3

    Science.gov (United States)

    Ivan P. Edwards; Donald R. Zak

    2011-01-01

    The long-term effects of rising atmospheric carbon dioxide (CO2) and tropospheric O3 concentrations on fungal communities in soil are not well understood. Here, we examine fungal community composition and the activities of cellobiohydrolase and N-acetylglucosaminidase (NAG) after 10 years of exposure to 1...

  6. Exposure to atmospheric pms, pahs, pcdd/fs and metals near an open air waste burning site in Beirut

    Directory of Open Access Journals (Sweden)

    Rima Baalbaki

    2016-12-01

    Full Text Available Baalbaki, R., El Hage, R., Nassar, J., Gerard, J., Saliba, N.B., Zaarour, R., Abboud, M., Wehbeh, F., Khalaf, L.K., Shihadeh, A.L., Saliba, N.A. 2016. Exposure to atmospheric PMS, PAHS, PCDD/FS and metals near an open air waste burning site in Beirut. Lebanese Science Journal, 17(2: 91-103. Since July 2015, Lebanon has experienced the worst solid waste management crisis in its history. Consequently, open-air waste burning in the vicinity of highly populated areas in Beirut has become a common practice. This study evaluates the effects of open-air dumping and burning on local air quality and public health. The levels of particulate matter (PM10, PM2.5, gaseous and particle-bound polycyclic aromatic hydrocarbons (PAHs, polychlorinated dibenzo-dioxins and furans (PCDD/Fs, and particle-bound metals at a residence close to waste burning are reported. Concentrations, determined between October 2 and December 2, 2015, were compared either to previous measurements or to measurements taken away from a nearby burning incident, and after it had rained. Subsequently, the cancer risk due to exposure to these chemicals was assessed. Results showed alarming increases in pollutant concentrations which was translated into an increase in short-term cancer risk from about 1 to 20 people per million on the days when waste was being burned. Findings were shared with the public to warn the community against the dangers of waste mismanagement, and underline the obvious need for solid waste management at the governmental and municipal levels.

  7. Assessment of Public Health Risks Associated with Atmospheric Exposure to PM2.5 in Washington, DC, USA

    Directory of Open Access Journals (Sweden)

    Vernon R. Morris

    2006-03-01

    Full Text Available In this research, we investigated the public health risks associated with atmospheric exposure to PM2.5 for different subpopulations (black, white, Hispanic, youth, adults, and elderly in the Washington, DC area. Washington, DC has long been considered a non-healthy place to live according to the American Lung Association due to its poor air quality. This recognition clearly includes the negative PM-related human health effects within the region. Specifically, DC fine particulate matter (PM2.5 [or particulate matter with an aerodynamic diameter less than 2.5 μm] poses notable health risks to subpopulations having an annual mean value of 16.70 μg/m3 during the years 1999-2004, exceeding the EPA National Ambient Air Quality Standard (NAAQS of 15 μg/m3. Incessant exposure to significant levels of PM has previously been linked to deleterious health effects, such as heart and lung diseases. The environmental quality and public health statistics of Washington, DC indicate the need for higher-resolution measurements of emissions, both spatially and temporally, and increased analysis of PM-related health effects. Our findings show that there are significant risks of ward-specific pediatric asthma emergency room visits (ERV. Results also illustrate lifetime excess lung cancer risks, exceeding the 1x10-6 threshold for the measured levels of particulate matter and heavy metals (chromium and arsenic on behalf of numerous subpopulations in the DC selected wards.

  8. 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.

  9. 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.

  10. 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

  11. Refrigeration Test Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The enclosed and environmentally controlled chamber is able to test four units (single-phase) simultaneously at conditions ranging from tundra to desert temperatures...

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. Evaporative deposition patterns of bacteria from a sessile drop: effect of changes in surface wettability due to exposure to a laboratory atmosphere.

    Science.gov (United States)

    Baughman, Kyle F; Maier, Raina M; Norris, Theresa A; Beam, Brooke M; Mudalige, Anoma; Pemberton, Jeanne E; Curry, Joan E

    2010-05-18

    Evaporative deposition from a sessile drop is a simple and appealing way to deposit materials on a surface. In this work, we deposit living, motile colloidal particles (bacteria) on mica from drops of aqueous solution. We show for the first time that it is possible to produce a continuous variation in the deposition pattern from ring deposits to cellular pattern deposits by incremental changes in surface wettability which we achieve by timed exposure of the mica surface to the atmosphere. We show that it is possible to change the contact angle of the drop from less than 5 degrees to near 20 degrees by choice of atmospheric exposure time. This controls the extent of drop spreading, which in turn determines the architecture of the deposition pattern.

  18. ASSIMILATION, RESPIRATION AND ALLOCATION OF CARBON IN PLANTAGO MAJOR AS AFFECTED BY ATMOSPHERIC CO2 LEVELS - A CASE-STUDY

    NARCIS (Netherlands)

    DENHERTOG, J; STULEN, [No Value; LAMBERS, H

    The response of Plantago major ssp. pleiosperma plants, grown on nutrient solution in a climate chamber, to a doubling of the ambient atmospheric CO2 concentration was investigated. Total dry matter production was increased by 30 % after 3 weeks of exposure, due to a transient stimulation of the

  19. 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.

  20. Assessment of exposure to atmospheric particles: contribution of individual measurements; Evaluation de l'exposition aux particules atmospheriques: apport des mesures individuelles

    Energy Technology Data Exchange (ETDEWEB)

    Mosqueron, L.; Momas, I. [Universite Rene Descartes, Faculte des Sciences Pharmaceutiques et Biologiques, Lab. d' Hygiene et de Sante Publique, 75 - Paris (France); Le Moullec, Y. [Laboratoire d' Hygiene de la Ville de Paris, 75 (France); Momas, I. [Direction de l' Action Sociale, de l' Enfance et de la Sante, Cellule Epidemiologie, 75 - Paris (France)

    2001-02-01

    There are few studies of individual exposure to atmospheric particles, because of the relatively bulky and noisy sampling devices. These personalized measurements, generally associated with micro-environmental measurements, are aimed at studying the distribution of individual exposure and identifying its main determinants. Methods: A synopsis of the methods implemented in such studies (populations studied, measurements strategies, questionnaires on time-activity patterns, residences and work place) was detailed. The major results are presented and discussed from an epidemiological point of view. Results: The individual exposure measured with portable devices generally were generally found to be higher than the estimations made by combining micro-environmental (outdoor and indoor) measurements and data from time-activity diaries. The difference between results of these two approaches, known as 'personal cloud', remains poorly understood. Correlations between individual measurements and outdoor concentrations are weak; nevertheless, day to day variations of these two series of measurements are better related. The main determinants of individual exposure to particles are identified but a quantification of their contribution remains difficult, except for passive smoking. Conclusion: Personal measurements cannot be used to estimate particle exposure in large scale epidemiological studies. This exposure needs to be modeled. (authors)

  1. A wet effluent denuder/mist-chamber coupled to ion chromatography for the continuous measurement of atmospheric HONO, HNO{sub 3}, NO{sub 3}{sup -} and SO{sub 4}{sup 2-}.

    Energy Technology Data Exchange (ETDEWEB)

    Zellweger, C.; Baltensperger, U. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Hofer, P. [EMPA, Duebendorf (Switzerland)

    1997-09-01

    A denuder/mist chamber system has been developed for the continuous automated measurement of low level concentrations of HONO, HNO{sub 3} as well as of NO{sub 3}{sup -} and SO{sub 4}{sup 2-}. (author) 2 figs., 1 ref.

  2. 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.

  3. Obelix Wire Chamber

    CERN Multimedia

    1986-01-01

    Two wire chambers made originally for the R807 Experiment at CERN's Intersecting Storage Rings. In 1986 they were used for the PS 201 experiment (Obelix Experiment) at LEAR, the Low Energy Antiproton Ring. The group of researchers from Turin, using the chambers at that time, changed the acquisition system using for the first time 8 bit (10 bit non linear) analog to digital conversion for incoming signals from the chambers. The acquisition system was controlled by 54 CPU and 80 digital signal processors. The power required for all the electronics was 40 kW. For the period, this system was one of the most powerful on-line apparatus in the world. The Obelix Experiment was closed in 1996. To find more about how a wire chamber works, see the description for object CERN-OBJ-DE-038.

  4. 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).

  5. Swirl chamber for vitrification of fly ashes

    Directory of Open Access Journals (Sweden)

    Zarzycki Robert

    2017-01-01

    Full Text Available The study presents the concept of a swirl chamber used for vitrification of fly ashes. It assumes the use of coal dust in the process of fly ash melting. The coal dust supplied to the swirl chamber and gasified in the atmosphere of O2, CO2 and H2O allows for obtaining combustible gases composed of CO and H2, which are burnt with the pneumatically supplied fly ash. The above process allows for obtaining a product in the form of a molten slag which does not contain coal grains. The study presents numerical calculations for the process of combustion and gasification of coal dust and opportunities for ensuring adequate parameters in the fly ash melting zone. The combustible gases obtained during the process of gasification can be supplied to the chamber of a pulverized-bed boiler.

  6. Target Chamber Manipulator

    Science.gov (United States)

    Tantillo, Anthony; Watson, Matthew

    2015-11-01

    A system has been developed to allow remote actuation of sensors in a high vacuum target chamber used with a particle accelerator. Typically, sensors of various types are placed into the target chamber at specific radial and angular positions relative to the beam line and target. The chamber is then evacuated and the experiments are performed for those sensor positions. Then, the chamber is opened, the sensors are repositioned to new angles or radii, and the process is repeated, with a separate pump-down cycle for each set of sensor positions. The new sensor positioning system allows scientists to pre-set the radii of up to a dozen sensors, and then remotely actuate their angular positions without breaking the vacuum of the target chamber. This reduces the time required to reposition sensors from 6 hours to 1 minute. The sensors are placed into one of two tracks that are separately actuated using vacuum-grade stepping motors. The positions of the sensors are verified using absolute optical rotary encoders, and the positions are accurate to 0.5 degrees. The positions of the sensors are electronically recorded and time-stamped after every change. User control is through a GUI using LabVIEW.

  7. The KLOE drift chamber

    CERN Document Server

    Adinolfi, M; Ambrosino, F; Andryakov, A; Antonelli, A; Antonelli, M; Anulli, F; Bacci, C; Bankamp, A; Barbiellini, G; Bellini, F; Bencivenni, G; Bertolucci, Sergio; Bini, C; Bloise, C; Bocci, V; Bossi, F; Branchini, P; Bulychjov, S A; Cabibbo, G; Calcaterra, A; Caloi, R; Campana, P; Capon, G; Carboni, G; Cardini, A; Casarsa, M; Cataldi, G; Ceradini, F; Cervelli, F; Cevenini, F; Chiefari, G; Ciambrone, P; Conetti, S; Conticelli, S; Lucia, E D; Robertis, G D; Sangro, R D; Simone, P D; Zorzi, G D; Dell'Agnello, S; Denig, A; Domenico, A D; Donato, C D; Falco, S D; Doria, A; Drago, E; Elia, V; Erriquez, O; Farilla, A; Felici, G; Ferrari, A; Ferrer, M L; Finocchiaro, G; Forti, C; Franceschi, A; Franzini, P; Gao, M L; Gatti, C; Gauzzi, P; Giovannella, S; Golovatyuk, V; Gorini, E; Grancagnolo, F; Grandegger, W; Graziani, E; Guarnaccia, P; Von Hagel, U; Han, H G; Han, S W; Huang, X; Incagli, M; Ingrosso, L; Jang, Y Y; Kim, W; Kluge, W; Kulikov, V; Lacava, F; Lanfranchi, G; Lee-Franzini, J; Lomtadze, F; Luisi, C; Mao Chen Sheng; Martemyanov, M; Matsyuk, M; Mei, W; Merola, L; Messi, R; Miscetti, S; Moalem, A; Moccia, S; Moulson, M; Müller, S; Murtas, F; Napolitano, M; Nedosekin, A; Panareo, M; Pacciani, L; Pagès, P; Palutan, M; Paoluzi, L; Pasqualucci, E; Passalacqua, L; Passaseo, M; Passeri, A; Patera, V; Petrolo, E; Petrucci, Guido; Picca, D; Pirozzi, G; Pistillo, C; Pollack, M; Pontecorvo, L; Primavera, M; Ruggieri, F; Santangelo, P; Santovetti, E; Saracino, G; Schamberger, R D; Schwick, C; Sciascia, B; Sciubba, A; Scuri, F; Sfiligoi, I; Shan, J; Silano, P; Spadaro, T; Spagnolo, S; Spiriti, E; Stanescu, C; Tong, G L; Tortora, L; Valente, E; Valente, P; Valeriani, B; Venanzoni, G; Veneziano, Stefano; Wu, Y; Xie, Y G; Zhao, P P; Zhou, Y

    2001-01-01

    The tracking detector of the KLOE experiment is 4 m diameter, 3.3 m length drift chamber, designed to contain a large fraction of the decays of low-energy K sub L produced at the Frascati DAPHINE phi-factory. The chamber is made by a thin carbon fiber structure and operated with a helium-based gas mixture in order to minimise conversion of low-energy photons and multiple scattering inside the sensitive volume. The tracking information is provided by 58 layers of stereo wires defing 12,582 cells, 2x2 cm sup 2 in size in the 12 innermost layers and 3x3 cm sup 2 in the outer ones. Details of the chamber design, calibration procedure and tracking performances are presented.

  8. 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.

  9. 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.

  10. 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.

  11. Exposure to polycyclic aromatic hydrocarbons in atmospheric PM1.0 of urban environments: Carcinogenic and mutagenic respiratory health risk by age groups.

    Science.gov (United States)

    Agudelo-Castañeda, Dayana M; Teixeira, Elba C; Schneider, Ismael L; Lara, Sheila Rincón; Silva, Luis F O

    2017-05-01

    We investigated the carcinogenic and mutagenic respiratory health risks related to the exposure to atmospheric PAHs in an urban area. Our study focused in the association of these pollutants and their possible effect in human health, principally respiratory and circulatory diseases. Also, we determined a relationship between the inhalation risk of PAHs and meteorological conditions. We validated the hypothesis that in winter PAHs with high molecular weight associated to submicron particles (PM1) may increase exposure risk, especially for respiratory diseases, bronchitis and pneumonia diseases. Moreover, in our study we verified the relationship between diseases and several carcinogenic PAHs (Ind, BbkF, DahA, BaP, and BghiP). These individual PAHs contributed the most to the potential risk of exposure for inhalation of PM1.0. Even at lower ambient concentrations of BaP and DahA in comparison with individual concentrations of other PAHs associated to PM1.0. Mainly, research suggests to include carcinogenic and mutagenic PAHs in future studies of environmental health risk due to their capacity to associate to PM10. Such carcinogenic and mutagenic PAHs are likely to provide the majority of the human exposure, since they originate from dense traffic urban areas were humans congregate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. 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.

  13. Scanning bubble chamber pictures

    CERN Multimedia

    1974-01-01

    These were taken at the 2 m hydrogen bubble chamber. The photo shows an early Shiva system where the pre-measurements needed to qualify the event were done manually (cf photo 7408136X). The scanning tables were located in bld. 12. Gilberte Saulmier sits on foreground, Inge Arents at centre.

  14. 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.

  15. Rocket Combustion Chamber Coating

    Science.gov (United States)

    Holmes, Richard R. (Inventor); McKechnie, Timothy N. (Inventor)

    2001-01-01

    A coating with the ability to protect (1) the inside wall (i.e., lining) of a rocket engine combustion chamber and (2) parts of other apparatuses that utilize or are exposed to combustive or high temperature environments. The novelty of this invention lies in the manner a protective coating is embedded into the lining.

  16. Chamber Profile Measurement System.

    Science.gov (United States)

    1980-10-01

    travel with the proper electronics. Other features of tihe gage assembly are: 1. Micrometer controlled down chamber positioning of the master template to...pressure sensitive "stiff stick" for infinitely varying the rate of travel from zero to maximum. A manual vernier control is incorporated to permit fine

  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. Critical Evaluation of Air-Liquid Interface Cell Exposure Systems for In Vitro Assessment of Atmospheric Pollutants##

    Science.gov (United States)

    Conventional in vitro exposure studies of airborne pollutants involve, for example, the addition of particulate matter (PM) or PM extracts to the cell culture medium, or the bubbling of gases into the culture medium; these methods alter the pollutant’s physical and chemical...

  19. Quantifying the "chamber effect" in CO2 flux measurements

    Science.gov (United States)

    Vihermaa, Leena; Childs, Amy; Long, Hazel; Waldron, Susan

    2014-05-01

    The significance of aquatic CO2 emissions has received attention in recent years. For example annual aquatic emissions in the Amazon basin have been estimated as 500 Mt of carbon1. Methods for determining the flux rates include eddy covariance flux tower measurements, flux estimates calculated from partial pressure of CO2 (pCO2) in water and the use floating flux chambers connected to an infra-red gas analyser. The flux chamber method is often used because it is portable, cheaper and allows smaller scale measurements. It is also a direct method and hence avoids problems related to the estimation of the gas transfer coefficient that is required when fluxes are calculated from pCO2. However, the use of a floating chamber may influence the flux measurements obtained. The chamber shields the water underneath from effects of wind which could lead to lower flux estimates. Wind increases the flux rate by i) causing waves which increase the surface area for efflux, and ii) removing CO2 build up above the water surface, hence maintaining a higher concentration gradient. Many floating chambers have an underwater extension of the chamber below the float to ensure better seal to water surface and to prevent any ingress of atmospheric air when waves rock the chamber. This extension may cause additional turbulence in flowing water and hence lead to overestimation of flux rates. Some groups have also used a small fan in the chamber headspace to ensure thorough mixing of air in the chamber. This may create turbulence inside the chamber which could increase the flux rate. Here we present results on the effects of different chamber designs on the detected flux rates. 1Richey et al. 2002. Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2. Nature 416: 617-620.

  20. Inhalation and dermal exposure to atmospheric polycyclic aromatic hydrocarbons and associated carcinogenic risks in a relatively small city.

    Science.gov (United States)

    Gungormus, Elif; Tuncel, Semra; Hakan Tecer, Lokman; Sofuoglu, Sait C

    2014-10-01

    The aim of this study was to conduct a carcinogenic risk assessment for exposure to polycyclic aromatic hydrocarbons (PAHs) via routes of inhalation and dermal contact. Concentrations of 19 PAH species were determined during a heating period at a site in the city of Balikesir, Turkey. Two questionnaires were administered to a sample of inhabitants to determine time-activity budgets and demographic information. The assessment was conducted for each participant and Balikesir population by deterministic and probabilistic approaches, respectively. Monte Carlo simulation was implemented to determine the population exposure-risk probability distributions. The estimates were based on benzo[a]pyrene equivalent (BaPeq) total PAH concentrations calculated using toxic equivalency factors. The mean and median BaPeq concentrations of gaseous and particulate phases were 3.25 and 1.34, and 38.5 and 34.0ng/m(3), respectively. Carcinogenic risk for inhalation exposure route was estimated by using two different slope factor values (3.9 and 304.5(mg/kg-day)(-1)), recommended by two different organizations, resulting in two (order(s) of magnitude apart) population risk ranges: 1.32×10(-7)-2.23×10(-4), and 1.61×10(-5)-7.95×10(-3), respectively. The population risks associated with dermal exposure were lower compared to those of inhalation, ranging from 6.58×10(-9) to 2.57×10(-6). The proportion of the population with risks higher than the general acceptable level (1.0×10(-6)) was estimated as >99 percent, for inhalation, and as 28 percent for dermal exposure route. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Study of spatiotemporal variation of atmospheric mercury and its human exposure around an integrated steel plant, India

    Science.gov (United States)

    Pervez, S.; Koshle, A.; Pervez, Y.

    2010-06-01

    Mercury release by coal combustion has been significantly increased in India. Mercury content in coal has been analyzed to 0.272 ppm by Central Pollution Control Board. Toxicological effects of elemental Hg (Hg0) exposure include respiratory and renal failures, cardiac arrest, and cerebral oedema, while subclinical exposure may induce kidney, behavioral, and cognitive dysfunctions. The present work is focused on dispersion pattern and inter-phase exchange phenomena of ambient mercury between air-particulate matter evaluations of alongwith dominance of various major routes of human exposure-dose response using regression analysis around an integrated steel plant in central India. Source-downwind type stratified random sampling plan using longitudinal study design has been adopted for ambient monitoring of total mercury, while representative sampling plant has been adopted for persona exposure-dose response study In space-time framework. Control sites and subjects have been chosen from uncontaminated area (100 km away from any industrial activities). 06 ambient air monitoring stations and 17 subjects from workers, non-workers but local residents' categories and from controlled sites have been chosen for the study. Samples of mercury biomarkers (blood, breast milk and urine) have also been collected from same subjects in each month during sampling period. The sampling period was March 2005 to February 2006 . Samples of 30% acidified KMnO4 for air-Hg absorption, PM10, RPM and biological samples were analyzed for total mercury by ICP-AES using standard methods. Local soils and ground water were also monitored for total mercury content during the sampling period. Results have shown that mercury concentration is very high compared to prescribed limits in all receptors. Results of exchange phenomenon have shown the higher transfer of mercury from air to particulate during combustion in steel plant environment due to presence of huge amount of iron particles, in contrast to

  2. 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.

  3. Imploded test-chamber for an ISR intersection

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    At the ISR intersection points the vacuum chambers had to be as "transparent" as possible, for the p-p collision product particles to reach the detectors with minimum hindrance. This meant the choice of a light, yet very strong, metal; minimum thickness; and corrugation for mechanical strength. The test-chamber seen here was made of 0.6 mm thick corrugated titanium, obviously not strong enough to withstand the atmospheric pressure.

  4. Anechoic Radio Frequency Test Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — This chamber is used for characterization test of such systems as communications gear, tanks, radar, missiles, and helicopters. The dimensions of the chamber are 114...

  5. Continuous flow, explosives vapor generator and sensor chamber

    Science.gov (United States)

    Collins, Greg E.; Giordano, Braden C.; Sivaprakasam, Vasanthi; Ananth, Ramagopal; Hammond, Mark; Merritt, Charles D.; Tucker, John E.; Malito, Michael; Eversole, Jay D.; Rose-Pehrsson, Susan

    2014-05-01

    A novel liquid injection vapor generator (LIVG) is demonstrated that is amenable to low vapor pressure explosives, 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine. The LIVG operates in a continuous manner, providing a constant and stable vapor output over a period of days and whose concentration can be extended over as much as three orders of magnitude. In addition, a large test atmosphere chamber attached to the LIVG is described, which enables the generation of a stable test atmosphere with controllable humidity and temperature. The size of the chamber allows for the complete insertion of testing instruments or arrays of materials into a uniform test atmosphere, and various electrical feedthroughs, insertion ports, and sealed doors permit simple and effective access to the sample chamber and its vapor.

  6. Study of the Durability of Doped Lanthanum Manganite and Cobaltite Cathode Materials under ''Real World'' Air Exposure Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Prabhakar [Univ. of Connecticut, Storrs, CT (United States); Mahapatra, Manoj [Univ. of Connecticut, Storrs, CT (United States); Ramprasad, Rampi [Univ. of Connecticut, Storrs, CT (United States); Minh, Nguyen [Univ. of California, San Diego, CA (United States); Misture, Scott [Alfred Univ., NY (United States)

    2014-11-30

    The overall objective of the program is to develop and validate mechanisms responsible for the overall structural and chemical degradation of lanthanum manganite as well as lanthanum ferrite cobaltite based cathode when exposed to “real world” air atmosphere exposure conditions during SOFC systems operation. Of particular interest are the evaluation and analysis of degradation phenomena related to and responsible for (a) products formation and interactions with air contaminants, (b) dopant segregation and oxide exolution at free surfaces, (c) cation interdiffusion and reaction products formation at the buried interfaces, (d) interface morphology changes, lattice transformation and the development of interfacial porosity and (e) micro-cracking and delamination from the stack repeat units. Reaction processes have been studied using electrochemical and high temperature materials compatibility tests followed by structural and chemical characterization. Degradation hypothesis has been proposed and validated through further experimentation and computational simulation.

  7. 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.

  8. Measurement of metal bioaccessibility in vegetables to improve human exposure assessments: field study of soil-plant-atmosphere transfers in urban areas, South China.

    Science.gov (United States)

    Xiong, TianTian; Dumat, Camille; Pierart, Antoine; Shahid, Muhammad; Kang, Yuan; Li, Ning; Bertoni, Georges; Laplanche, Christophe

    2016-12-01

    The quality of cultivated consumed vegetables in relation to environmental pollution is a crucial issue for urban and peri-urban areas, which host the majority of people at the global scale. In order to evaluate the fate of metals in urban soil-plant-atmosphere systems and their consequences on human exposure, a field study was conducted at two different sites near a waste incinerator (site A) and a highway (site B). Metal concentrations were measured in the soil, settled atmospheric particulate matter (PM) and vegetables. A risk assessment was performed using both total and bioaccessible metal concentrations in vegetables. Total metal concentrations in PM were (mg kg-1): (site A) 417 Cr, 354 Cu, 931 Zn, 6.3 Cd and 168 Pb; (site B) 145 Cr, 444 Cu, 3289 Zn, 2.9 Cd and 396 Pb. Several total soil Cd and Pb concentrations exceeded China's Environmental Quality Standards. At both sites, there was significant metal enrichment from the atmosphere to the leafy vegetables (correlation between Pb concentrations in PM and leaves: r = 0.52, p vegetables were therefore above or just under the maximum limit levels for foodstuffs according to Chinese and European Commission regulations. High metal bioaccessibility in the vegetables (60-79 %, with maximum value for Cd) was also observed. The bioaccessible hazard index was only above 1 for site B, due to moderate Pb and Cd pollution from the highway. In contrast, site A was considered as relatively safe for urban agriculture.

  9. Wire chambers revisited.

    Science.gov (United States)

    Ott, R J

    1993-04-01

    Detectors used for radioisotope imaging have, historically, been based on scintillating crystal/photomultiplier combinations in various forms. From the rectilinear scanner through to modern gamma cameras and positron cameras, the basic technology has remained much the same. Efforts to overcome the limitations of this form of technology have foundered on the inability to reproduce the required sensitivity, spatial resolution and sensitive area at acceptable cost. Multiwire proportional chambers (MWPCs) have long been used as position-sensitive charged particle detectors in nuclear and high-energy physics. MWPCs are large-area gas-filled ionisation chambers in which large arrays of fine wires are used to measure the position of ionisation produced in the gas by the passage of charged particles. The important properties of MWPCs are high-spatial-resolution, large-area, high-count-rate performance at low cost. For research applications, detectors several metres square have been built and small-area detectors have a charged particle resolution of 0.4 mm at a count rate of several million per second. Modification is required to MWPCs for nuclear medicine imaging. As gamma rays or X-rays cannot be detected directly, they must be converted into photo- or Compton scatter electrons. Photon-electron conversion requires the use of high atomic number materials in the body of the chamber. Pressurised xenon is the most useful form of "gas only" photon-electron convertor and has been used successfully in a gamma camera for the detection of gamma rays at energies below 100 keV. This camera has been developed specifically for high-count-rate first-pass cardiac imaging. This high-pressure xenon gas MWPC is the key to a highly competitive system which can outperform scintillator-based systems. The count rate performance is close to a million counts per second and the intrinsic spatial resolution is better than the best scintillator-based camera. The MWPC camera produces quantitative

  10. Review of wire chamber aging

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Safety-Enclosure System For MOCVD Process Chamber

    Science.gov (United States)

    Singletery, James, Jr.; Velasquez, Hugo; Warner, Joseph

    1995-01-01

    Safety-enclosure system filled with nitrogen surrounds reaction chamber in which metallo-organic chemical vapor deposition (MOCVD) performed. Designed to protect against explosions and/or escaping toxic gases and particulates. Gas-purification subsystem ensures during loading and unloading of process materials, interior of MOCVD chamber exposed to less than 1 ppm of oxygen and less than 5 ppm of water in nitrogen atmosphere. Toxic byproducts of MOCVD process collected within inert atmosphere. Enclosure strong enough to contain any fragments in unlikely event of explosion.

  12. Noise exposure under hyperbaric conditions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    Objective evidence exists that divers demonstrate a hearing deficit greater than would be expected from ageing effects alone. Deafness in divers may be caused by a number of factors other than exposure to excessive noise levels, eg barotrauma, ear infection etc. This review concentrates on the concern that exposure of commercial divers to noise while at work may cause a hearing deficit. Sound pressure levels recorded both underwater and in diving chambers often exceed those allowable to workers onshore. However, the sound perceived by the diver is modified both in amplitude and in frequency when he is either underwater or in pressurised chambers. Broadly the effect of this modification is to attenuate the sound and thus offer some protection from high noise levels. The degree of attentuation varies with the frequency of the sound, however it is also possible under specific conditions associated with gas density for the sensitivity to particular frequencies to be amplified above that for normal atmospheric air. The levels of sound observed from some underwater tools are of concern even after allowing for a significant de-sensitisation of the divers` hearing. Reports of tinnitus and temporary hearing loss following a dive are sure signs that the noise levels have been harmful. It is not possible at present to describe risk criteria for hearing damage due to noise exposure associated with diving. (author)

  13. Posterior chamber pseudophakia.

    Science.gov (United States)

    Simcoe, C W

    1982-01-01

    Anatomically, the most physiological type of implant is that of the posterior chamber of the eye. After a brief historical review of these implants, two models differing by their loops are compared, these being either in the form of a J with narrow extremities or in the form of a C. The latter model possesses definite advantages. Firstly, the point of pressure on the lens capsule is less concentrated, reducing the pressure exerted by the loops and thus avoiding rupture of the zonular ciliaris, Secondly, contact in the form of an are prevents movement of the implant around its axis, a factor favorizing capsule slipping. Thirdly, the improved pressure distribution of the loops resulting from their greater flexibility also prevents the "windscreen wiper syndrome", providing improved stability of the implant. The technique employed avoids all contact taking place with the endothelium. The upper loop is placed in position after closure of the incision. Results in 1532 cases were very positive, and studies are currently being conducted with an implant with four loops in which the optic is within the posterior chamber, and which could be positioned after intracapsular extraction. A system of irrigation-aspiration is described which employs a fine curved canula that is easier to manage and permits improved cleaning of the capsule. Emphasis is placed on the need for narrow, deep, corneal sutures to reduce postoperative astigmatism.

  14. 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...

  15. Recommended values of the humidity correction factor k{sub n} for determining exposure in an X-ray beam with free-air chambers; Valores recomendados del factor de correccion por humedad, k{sub h} para la determinacion de la exposicion en un haz de rayos X usando camaras de paredes de aire

    Energy Technology Data Exchange (ETDEWEB)

    Los Arcos, J.M.; Brosed, A.

    1983-07-01

    The experimental values stated by CCEMRI (Section I) concerning the humidity correction factor k{sub h} required for determining exposure in an X-ray beam with free-air chambers are commented and a method to estimate k{sub n} numerically, at any particular combination of relative humidity, pressure and temperature, la explained. A table of k{sub h}, calculated for relative humidity varying from 0% to 90%, for pressures in the range of 70 kPa to 104kPa and temperatures between 15 degree centigree and 30 degree centigree, is included. (Author) 10 refs.

  16. Michigan ATLAS MDT Chamber Mass Production

    CERN Document Server

    Diehl, E; Levin, D; McKee, S; Neal, H; Schick, H; Tarle, G; Thun, R; Weaverdyck, C; Xu, Q; Zhao, Z; Zhou, B

    2001-01-01

    This paper describes the ATLAS MDT precision muon chamber construction at the University of Michigan. The chamber assembly facilities, the jigging set up, alignment procedures, and other measurements necessary for chamber assembly are described. The chamber quality assurance monitoring procedures and data for the first year mass production are presented. The chamber gas system assembly facilities, and the chamber leak test procedure together with data also reported. The chamber production database, which monitors chamber production, is also discussed.

  17. 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

  18. Low cost transportable device for transference of atmosphere sensitive materials from glove box to SEM

    DEFF Research Database (Denmark)

    Bentzen, Janet Jonna; Saxild, Finn B.

    Moisture or air sensitive materials are often encountered within several highly important fields such as catalyst R&D, pharmaceutical R&D, and battery R&D. Essential to all materials research and development is microstructure characterization, which often implies electron microscopy. Entering...... the field of high energy battery research involving highly reactive metals, e.g. lithium, we needed a means of transferring atmosphere sensitive materials from the protective atmosphere of a glove box, avoiding air exposure, to a sample chamber of a scanning electron microscope. Thus, we constructed a low...

  19. The ALICE time projection chamber

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    This time projection chamber is part of the ALICE detector on the new LHC accelerator at CERN. Particles produced in collisions at the core of the detector will follow paths outward through the various sub-detector layers. If these particles carry a charge, they will ionise the gas contained within this chamber producing an electric signal as the ions drift in the chamber's electric field.

  20. The multimedia models for the evaluation of exposure bond to the atmospheric emissions of classified installations; Les modeles multimedia pour l'evaluation des expositions liees aux emissions atmospheriques des installations classees

    Energy Technology Data Exchange (ETDEWEB)

    Bonnard, R

    2001-12-15

    Risk assessment and environmental impacts studies are realized to preserve the public health. Today one of the most used approach is the use of an atmospheric dispersion model to assess the risks. The data are then injected in a calculation software of exposure bond to polluted soils, to evaluate the risks of non direct exposure. This report details and evaluates the models corresponding to the need: the methodology for assessing Health Risks associated with multiple pathways of exposure to combustor, human health risk assessment proto col for hazardous waste combustion facilities, EUSES, CALTOX, MEPAS, MEND-TOX, RESRAD, MMSOILS, FRAMES-HWIR, PC-GEMS and TRIM. (A.L.B.)

  1. Portable electron beam weld chamber

    Science.gov (United States)

    Lewis, J. R.; Dimino, J. M.

    1972-01-01

    Development and characteristics of portable vacuum chamber for skate type electron beam welding are discussed. Construction and operational details of equipment are presented. Illustrations of equipment are provided.

  2. The Big European Bubble Chamber

    CERN Multimedia

    1977-01-01

    The 3.70 metre Big European Bubble Chamber (BEBC), dismantled on 9 August 1984. During operation it was one of the biggest detectors in the world, producing direct visual recordings of particle tracks. 6.3 million photos of interactions were taken with the chamber in the course of its existence.

  3. Characterization of a Reverberation Chamber

    Science.gov (United States)

    2015-10-01

    applied to the same device inside another facility, such as a gigahertz transverse electromagnetic (GTEM) or fully- anechoic chamber for further...and found to be consistent; reflections measured from inside the chamber yielded heavy spiking. The antenna used to transmit power into the room was

  4. National Ignition Facility Target Chamber

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-10-05

    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

  5. 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).

  6. Transfer Chamber for DBD Surface Treatment and Analysis

    Science.gov (United States)

    Faust, Jessica; Gershman, Sophia; Daniels, Ryan

    2012-10-01

    Materials that are hydrophobic, smooth, and have low surface tension lead to poor adhesion for printing and coating. Surface modification using atmospheric pressure dielectric barrier discharge (DBD) improves adhesion by activating the surface, increasing its roughness and functionalizing. We have constructed and tested a DBD discharge system that uses a 15kV, 800-1350Hz pulsed dc source and a mixture of gasses at 300-600Torr. Treated surfaces are studied using X-ray photoelectron spectroscopy, Auger electron spectroscopy, and other methods that require high vacuum environment. We designed a portable transfer chamber to move the sample from the atmospheric pressure treatment chamber to a high vacuum surface analysis chamber with minimal interaction with the environment. The transfer chamber was designed to meet the specific requirements of each system; a bellows drive and sample holder to manually move the sample into the transfer chamber; the ability to fill with pure nitrogen gas to prevent contamination of the sample surface; constructed to withstand a range of pressures from 300 to 10-8Torr; the ability to connect compatibly with each system. Proper surface characterization of the sample is crucial to designing an effective treatment system.

  7. Materials screening chamber for testing materials resistance to atomic oxygen

    Science.gov (United States)

    Pippin, H. G.; Carruth, Ralph

    1989-01-01

    A unique test chamber for exposing material to a known flux of oxygen atoms is described. The capabilities and operating parameters of the apparatus include production of an oxygen atom flux in excess of 5 x 10 to the 16th atoms/sq cm-sec, controlled heating of the sample specimen, RF circuitry to contain the plasma within a small volume, and long exposure times. Flux measurement capabilities include a calorimetric probe and a light titration system. Accuracy and limitations of these techniques are discussed. An extension to the main chamber to allow simultaneous ultraviolet and atomic oxygen exposure is discussed. The oxygen atoms produced are at thermal energies. Sample specimens are maintained at any selected temperature between ambient and 200 C, to within + or - 2 C. A representative example of measurements made using the chamber is presented.

  8. Purging device for suppression chamber

    Energy Technology Data Exchange (ETDEWEB)

    Yoshino, Koichi.

    1987-11-14

    Purpose: To completely drive out air or the like in the suppression chamber in a short period of time thereby protect bent pipes from embrittled rupture. Constitution: Nitrogen gases, etc. entering through the inlet penetration to the inside of a reactor container are guided downwardly through communication pipeways, and the released downwardly in a stable manner while the blowing speed being retained by blowing mechanisms. Released nitrogen gases, etc. diffuse along the water surface of the suppression chamber and fill the inside of the chamber from below. Air, etc. in the suppression chamber prior to the supply of nitrogen gas, etc. is discharged through the exit penetration from the purging discharge pipe smoothly to the outside. In this way, air is replaced with nitrogen gas, etc., the released nitrogen is not directly blown to bent pipe, the operation is simplified, and the charge/discharge operation can be made in a short time efficiently. (Kamimura, M.).

  9. Vaporization chambers and associated methods

    Science.gov (United States)

    Turner, Terry D.; Wilding, Bruce M.; McKellar, Michael G.; Shunn, Lee P.

    2017-02-21

    A vaporization chamber may include at least one conduit and a shell. The at least one conduit may have an inlet at a first end, an outlet at a second end and a flow path therebetween. The shell may surround a portion of each conduit and define a chamber surrounding the portion of each conduit. Additionally, a plurality of discrete apertures may be positioned at longitudinal intervals in a wall of each conduit, each discrete aperture of the plurality of discrete apertures sized and configured to direct a jet of fluid into each conduit from the chamber. A liquid may be vaporized by directing a first fluid comprising a liquid into the inlet at the first end of each conduit, directing jets of a second fluid into each conduit from the chamber through discrete apertures in a wall of each conduit and transferring heat from the second fluid to the first fluid.

  10. The multigap resistive plate chamber

    Energy Technology Data Exchange (ETDEWEB)

    Zeballos, E. Cerron [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Crotty, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Hatzifotiadou, D. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Valverde, J. Lamas [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Univ. Louis Pasteur, Strasbourg (France); Neupane, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Williams, M. C. S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Zichichi, A. [Univ. of Bologna, Bologna (Italy)

    2015-02-03

    The paper describes the multigap resistive plate chamber (RPC). This is a variant of the wide gap RPC. However it has much improved time resolution, while keeping all the other advantages of the wide gap RPC design.

  11. Herds of methane chambers grazing bubbles

    Science.gov (United States)

    Grinham, Alistair; Dunbabin, Matthew

    2014-05-01

    Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique

  12. 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.

  13. Radon detection in conical diffusion chambers: Monte Carlo calculations and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Rickards, J.; Golzarri, J. I.; Espinosa, G., E-mail: espinosa@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México Circuito de la Investigación Científica, Ciudad Universitaria México, D.F. 04520, México (Mexico); Vázquez-López, C. [Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN Ave. IPN 2508, Col. San Pedro Zacatenco, México 07360, DF, México (Mexico)

    2015-07-23

    The operation of radon detection diffusion chambers of truncated conical shape was studied using Monte Carlo calculations. The efficiency was studied for alpha particles generated randomly in the volume of the chamber, and progeny generated randomly on the interior surface, which reach track detectors placed in different positions within the chamber. Incidence angular distributions, incidence energy spectra and path length distributions are calculated. Cases studied include different positions of the detector within the chamber, varying atmospheric pressure, and introducing a cutoff incidence angle and energy.

  14. Anterior chamber depth during hemodialysis

    Directory of Open Access Journals (Sweden)

    Gracitelli CPB

    2013-08-01

    Full Text Available Carolina Pelegrini Barbosa Gracitelli,1 Francisco Rosa Stefanini,1 Fernando Penha,1 Miguel Ângelo Góes,2 Sérgio Antonio Draibe,2 Maria Eugênia Canziani,2 Augusto Paranhos Junior1 1Ophthalmology Department, 2Division of Nephrology, Federal University of São Paulo – UNIFESP, São Paulo, Brazil Background: Exacerbation of chronic glaucoma or acute glaucoma is occasionally observed in patients undergoing hemodialysis (HD because of anterior chamber depth changes during this therapy. Purpose: To evaluate anterior chamber depth and axial length in patients during HD sessions. Methods: A total of 67 eyes of 35 patients were prospectively enrolled. Axial length and anterior chamber depth were measured using ultrasonic biometry, and these measures were evaluated at three different times during HD sessions. Body weight and blood pressure pre- and post-HD were also measured. Results: There was no difference in the axial length between the three measurements (P = 0.241. We observed a significantly decreased anterior chamber depth (P = 0.002 during HD sessions. Conclusion: Our results support the idea that there is a change in anterior chamber depth in HD sessions. Keywords: anterior chamber, hemodialysis, axial length, acute angle-closure glaucoma

  15. Development of secondary chamber for tar cracking–improvement of wood pyrolysis performance in pre-vacuum chamber

    Science.gov (United States)

    Siahaan, S.; Homma, H.; Homma, H.

    2018-02-01

    Energy crisis and global warming, in other words, climate change are critical topics discussed in various parts of the world. Global warming primarily result from too much emission of carbon dioxide (CO2) in the atmosphere. To mitigate global warming, or climate change and improve electrification in rural areas, wood pyrolysis technology is developed in a laboratory scale, of which gases are directly applicable to the gas engine generator. Our laboratory has developed a prototype of wood pyrolysis plant with a pre-vacuum chamber. However, tar yield was around 40 wt% of feedstock. This research aims to reduce tar yield by secondary tar cracking. For the secondary tar cracking, a secondary pre-vacuum chamber is installed after primary pre-vacuum chamber. Gases generated in the primary pre-vacuum chamber are lead into the secondary chamber that is heated up to 1000 K. This paper reports performance of the secondary chamber for secondary tar cracking in homogeneous mode and heterogeneous mode with char.

  16. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  17. Development and validation of inexpensive, automated, dynamic flux chambers

    Directory of Open Access Journals (Sweden)

    B. B. Almand-Hunter

    2015-01-01

    Full Text Available We developed and validated an automated, inexpensive, and continuous multiple-species gas-flux monitoring system that can provide data for a variety of relevant atmospheric pollutants, including O3, CO2, and NOx. Validation consisted of conducting concurrent gas-phase dry-deposition experiments, using both dynamic flux chambers and an eddy-covariance system, in a grassy clearing in the Duke Forest (Chapel Hill, NC. Experiments were carried out in June and September under a variety of meteorological conditions. Ozone-deposition measurements from the two methods matched very well (4–10% difference in mean flux rate when the leaf-area index (LAI inside the chambers was representative of the average LAI in the field. The dynamic flux chambers can be considered an accurate measurement system under these conditions.

  18. Characterization of a free air ionization chamber for low energies

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Natalia F.; Xavier, Marcos; Vivolo, Vitor; Caldas, Linda V.E., E-mail: nsilva@ipen.br, E-mail: mxavier@ipen.br, E-mail: vivolo@ipen.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Free air ionization chambers are used by most primary metrology laboratories as primary standards of the quantities air kerma and exposure in X-ray beams. The free air ionization chamber for low energies of the Calibration Laboratory (LCI) of IPEN showed in a characterization test a problem in the set responsible for the variation of its sensitive volume. After a modification in the support of the micrometers used for the movement of the internal cylinder and the establishment of a new alignment system protocol, the tests were redone. The objective of this work was to present the results obtained in the new condition. (author)

  19. Plasma chemistry in wire chambers

    Energy Technology Data Exchange (ETDEWEB)

    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 {sup 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.

  20. Evaluation of the Effect of Moist Chamber Spectacles in Patients With Dry Eye Exposed to Adverse Environment Conditions.

    Science.gov (United States)

    Ogawa, Mamoru; Dogru, Murat; Toriyama, Naoki; Yamaguchi, Takefumi; Shimazaki, Jun; Tsubota, Kazuo

    2017-10-31

    To evaluate the effect of moist chamber spectacle wear on the ocular surface and tear functions in a controlled wind exposure environment. Twenty-eight eyes of 14 probable dry eye subjects (4 men, 10 women; mean age: 34.5 years) underwent constant wind exposure for 10 min without spectacle, with conventional spectacle wear, and with moist chamber spectacle wear. Dryness Visual Analog Scale (VAS) scores, tear evaporation, blink rate, tear film breakup testing, and fluorescein staining were performed before and after wind exposure. The mean dryness VAS score after wind exposure was significantly higher when no spectacles were worn or when conventional spectacles with no moist chambers were worn compared with after exposure scores when moist chamber spectacles were worn (P=0.02). The mean of tear evaporation rate from the ocular surface and blink rate increased significantly with wind exposure when no spectacles were worn or when conventional spectacles with no moist chambers were worn (P=0.04). There were no significant changes before and after wind exposure when the moist chamber spectacles were worn (P=0.1). Moist chamber spectacles appear to have favorable effects on dry eye symptomatology, tear stability, and blink rates in adverse environment conditions such as wind exposure.

  1. A dual deformable reverberation chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2009-01-01

    There is disclosed an arrangement for measuring the effectiveness of a shielding material against electromagnetic fields. The arrangement comprises a first and a second reverberation chamber sharing a common wall. The common wall is partly made of the shielding material. A first antenna is arranged

  2. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The same vacuum chamber as in 7810256, read the detailed description there. Here, the 4 strip-shaped ion-getter pumps are poised at the entrance to their slots. Ion-getter pumps were not retained, thermal getter pumps were chosen instead (see 8301153 and 8305170).

  3. 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.

  4. DELPHI's Ring Imaging Cherenkov Chamber

    CERN Multimedia

    1989-01-01

    The hundreds of mirrors around this Ring Imaging Cherenkov Chamber reflect cones of light created by fast moving particles to a detector. The velocity of a particle can be measured by the size of the ring produced on the detector. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  5. Toxicity Evaluation of Exposure to an Atmospheric Mixture of Polychlorinated Biphenyls by Nose-Only and Whole-Body Inhalation Regimens.

    Science.gov (United States)

    Hu, Xin; Adamcakova-Dodd, Andrea; Lehmler, Hans-Joachim; Gibson-Corley, Katherine; Thorne, Peter S

    2015-10-06

    The health risk of inhalation exposure to polychlorinated biphenyls (PCB) cannot be assessed with high confidence due to the lack of rigorous inhalation studies. One uncertainty rests on exposure regimen, as whole-body exposure systems allow oral PCB intake that confounds the exposure. We conducted contemporaneous PCB inhalation exposures with whole-body and nose-only exposure methods. Female Sprague-Dawley rats were concurrently exposed to vapor-phase PCBs (533 ± 93 μg/m(3)) generated from PCB11-supplemented Chicago Air Mixture resembling the Chicago airshed, 4 h/day, 6 days/week, for 4 weeks. Congener-specific analysis showed 1.5-fold higher ∑PCBs in the lungs of nose-only exposed than the whole-body exposed animals (p = 0.0024). Higher ∑PCB concentrations were also found in the sera, livers, brains, and adipose tissue of nose-only exposed animals (1.1-1.5-fold), but these increases were not statistically significant. Congener profiles of five tissue types were dominated by PCB 28/31 and higher-chlorinated congeners in both groups reflecting rapid metabolism of other lower-chlorinated PCBs. No toxicity was seen regarding metabolic enzyme expression, glutathione, or histopathology. However, diminished weight gain and reduced plasma total thyroxine levels were found in both groups compared with controls, after exposure to 76 μg/m(3) ∑PCBs as adjusted for continuous exposure. Hepatic lipid peroxidation was also elevated in the nose-only group. Our study shows that prolonged nose-only exposure was well-tolerated and eliminated the need for housing animals outside the vivarium, thus was preferred for long-term PCB inhalation studies.

  6. Global atmospheric changes.

    OpenAIRE

    Piver, W T

    1991-01-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the proces...

  7. Metal explosion chambers: designing, manufacturing, application

    Science.gov (United States)

    Stoyanovskii, O. I.; Zlobin, B. S.; Shtertser, A. A.; Meshcheryakov, Y. P.

    2017-10-01

    Designing of explosion chambers is based on research investigations of the chamber body stress-strain state, which is determined by numerical computation and experimentally by the strain gage technique. Studies show that chamber bottoms are the most loaded elements, and maximal stresses arise in chamber poles. Increasing the shell thickness around poles by welding-in an insert is a simple and saving way to solve this problem. There are structural solutions, enabling reliable hermetic closure and preventing leakage of detonation products from the chamber. Explosion chambers are employed in scientific research and in different industrial applications: explosive welding and hardening, synthesis of new materials, disposal of expired ammunition, and etc.

  8. 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...... conditions, and the environment can be carefully controlled and easily changed. The protocols in this unit include construction of the flow chamber and the bubble trap, assembly and sterilization of the flow chamber system, inoculation of the flow chambers, running of the system, image capture and analysis...

  9. LBA-ECO TG-07 Soil CO2 Flux by Automated Chamber, Para, Brazil: 2001-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — Measurements of the soil-atmosphere flux of CO2 were made at the km 67 flux tower site in the Tapajos National Forest, Santarem, Para, Brazil. Eight chambers were...

  10. A compact multi-chamber setup for degradation and lifetime studies of organic solar cells

    DEFF Research Database (Denmark)

    Gevorgyan, Suren; Jørgensen, Mikkel; Krebs, Frederik C

    2011-01-01

    A controlled atmosphere setup designed for long-term degradation studies of organic solar cells under illumination is presented. The setup was designed with ease-of-use and compactness in mind and allows for multiple solar cells distributed on four glass substrates to be studied in four different...... chambers with temperature and atmosphere control. The four chambers are situated at close proximity in the setup thereby allowing the solar cells to be subjected to as uniform an illumination distribution as possible for the given solar simulator employed. The cell substrates serve as the front window...... and present a tight seal. Hence no illumination correction needs to be performed due to transmission and reflection losses as otherwise seen with test chambers employing a window as a seal. The solar cells in each chamber are continuously and individually electrically monitored under biased conditions...

  11. 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).

  12. 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.

  13. Soil respiration, root biomass, and root turnover following long-term exposure of northern forests to elevated atmospheric CO2 and tropospheric O3

    Science.gov (United States)

    Kurt S. Pregitzer; Andrew J. Burton; John S. King; Donald R. Zak

    2008-01-01

    The Rhinelander free-air CO2 enrichment (FACE) experiment is designed to understand ecosystem response to elevated atmospheric carbon dioxide (+CO2) and elevated tropospheric ozone (+O3). The objectives of this study were: to understand how soil respiration responded to the experimental treatments; to...

  14. Two Italian pupils building an MRPC muon chamber in CERN’s Building 29

    CERN Document Server

    2005-01-01

    For several months, Italian secondary school pupils have been coming to CERN each week and heading for Building 29. They are participating in the EEE (Extreme Energy Events) Project, the aim of which is to carry out a real-life experiment in search of large atmospheric showers using muon detectors located in their schools. In this hall at CERN they are helping to build and test muon chambers - MRPCs (Multigap Resistive Plate Chambers).

  15. 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...

  16. Exposure of unsuspecting workers to deadly atmospheres in below-ground confined spaces and investigation of related whole-air sample composition using adsorption gas chromatography.

    Science.gov (United States)

    Smith, Philip A; Lockhart, Bonnie; Besser, Brett W; Michalski, Michael A R

    2014-01-01

    Hazardous atmospheres in confined spaces may be obvious when a source of air contamination or oxygen (O2) deficiency is recognized. Such is often the case in general industry settings, especially with work processes which create hazardous atmospheres that may be anticipated. Hazards present in active sewers are also well recognized; but the possibility that O2 deficiency or high airborne contaminant concentrations may exist in new construction sewers or storm drains has been repeatedly ignored with deadly results. Low O2 and high carbon dioxide (CO2) concentrations may exist in new construction manholes that have not yet been connected to an active sewer or drain system, and these concentrations have been shown to vary over time. A recent incident is described where workers repeatedly entered such a confined space without incident, but subsequent entry resulted in a fatality and a near-miss for a co-worker rescuer. Additional cases are discussed, with an emphasis placed on elevated CO2 concentrations as a causative factor. A description is provided for the adsorptive gas chromatography whole-air analysis methodology used to quantitatively determine atmospheric conditions present at this type of fatality site or others after an incident, and for the gas chromatography-mass spectrometry method used to provide confirmation of analyte identity with high certainty. Many types of confined spaces may be encountered in addition to the underground varieties discussed, and many possible atmospheric hazards are possible. The definitive whole-air analysis approach described here may be of use and should be considered to investigate many confined space fatality and near-miss cases, and to better understand the causes of dangerous atmosphere conditions that may arise in confined spaces.

  17. Design of a Fully Anechoic Chamber

    OpenAIRE

    Rusz, Roman

    2015-01-01

    This thesis deals with fully anechoic chamber design. The main aim of this thesis is to design fully anechoic chamber according to acoustics laws and customers (Honeywell’s) requirements. The fully anechoic chamber will be used for measuring sound and vibration quantities. This work is divided into two main parts. The first part deals with the general anechoic chamber theory and all its related design aspects. The second part, practical part, focus on specific design according to requirements...

  18. Evolutionary differences in Δ13C detected between spore and seed bearing plants following exposure to a range of atmospheric O2:CO2 ratios; implications for paleoatmosphere reconstruction

    Science.gov (United States)

    Porter, Amanda S.; Yiotis, Charilaos; Montañez, Isabel P.; McElwain, Jennifer C.

    2017-09-01

    The stable carbon isotopes of fossil plants are a reflection of the atmosphere and environment in which they grew. Fossil plant remains have thus stored information about the isotopic composition and concentration of atmospheric carbon dioxide (pCO2) and possibly pO2 through time. Studies to date, utilizing extant plants, have linked changes in plant stable carbon isotopes (δ13Cp) or carbon isotope discrimination (Δ13C) to changes in pCO2 and/or pO2. These studies have relied heavily on angiosperm representatives, a phylogenetic group only present in the fossil record post-Early Cretaceous (∼140 million years ago (mya)), whereas gymnosperms, monilophytes and lycophytes dominated terrestrial ecosystems prior to this time. The aim of this study was to expand our understanding of carbon isotope discrimination in all vascular plant groups of C3 plants including lycophytes, monilophytes, gymnosperms and angiosperms, under elevated CO2 and sub-ambient O2 to explore their utility as paleo-atmospheric proxies. To achieve this goal, plants were grown in controlled environment chambers under a range of O2:CO2 ratio treatments. Results reveal a strong phylogenetic dependency on Δ13C, where spore-bearing (lycophytes and monilophytes) have significantly higher 13C discrimination than seed plants (gymnosperms and angiosperms) by ∼5‰. We attribute this strong phylogenetic signal to differences in Ci/Ca likely mediated by fundamental differences in how spore and seed bearing plants control stomatal aperture. Decreasing O2:CO2 ratio in general resulted in increased carbon isotope discrimination in all plant groups. Notably, while all plant groups respond unidirectionally to elevated atmospheric CO2 (1900 ppm and ambient O2), they do not respond equally to sub-ambient O2 (16%). We conclude that (1) Δ13C has a strong phylogenetic or 'reproductive grade' bias, whereby Δ13C of spore reproducing plants is significantly different to seed reproducing taxa. (2) Δ13C increases

  19. Comparative Toxicity of Simulated Smog Atmospheres in ...

    Science.gov (United States)

    Effects of complex regional multipollutant mixtures on disease expression in susceptible populations are dependent on multiple exposure and susceptibility factors. Differing profiles of ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM), which are key components of smog, and other hazardous pollutants may develop as a result of regional-specific geographic and urban environment characteristics. We investigated the pulmonary effects of two smog mixtures with different compositions in a mouse model of allergic airway disease to determine which source profile had the greatest impact on pulmonary endpoints. A hydrocarbon mixture was combined with NO gas in the presence of UV light in a controlled setting. Simulated smog atmosphere 1 (SSA-1) consisted of concentrations of 1070 µg/m3 secondary organic aerosol (SOA), 0.104 ppm O3, and 0.252 ppm NO2. SSA-2 consisted of a starting concentration of 53 µg/m3 SOA, 0.376 ppm O3, and 0.617 ppm NO2. An increased aerosol concentration was noted in the exposure chamber. Healthy and house dust mite (HDM)-sensitized (allergic) female BALB/cJ mice were exposed 4 hr/day for 1 or 5 days to either smog mixture or clean air. Two days after HDM challenge, airway mechanics were tested in anesthetized ventilated mice. Following methacholine aerosol challenge, increased airway resistance and elastance and a decrease in lung compliance were consistently observed in air- and smog-exposed HDM-allergic groups compared with non-a

  20. Vacuum chamber at intersection I-6

    CERN Multimedia

    1971-01-01

    The vacuum chamber at intersection region I-6, one of these where experiments in colliding-beam physics will be taking place. The "wheels" prevent the thin wall (1.5 mm) of the chamber from collapsing. The chamber is equipped with heating tapes and its wrapped in thermal insulation. Residual gas pressure at this and other similar regions is around 10_11.

  1. Making a Fish Tank Cloud Chamber

    Science.gov (United States)

    Green, Frances

    2012-01-01

    The cloud chambers described here are large, made from readily available parts, simple to set up and always work. With no source in the chamber, background radiation can be observed. A large chamber means that a long rod containing a weakly radioactive material can be introduced, increasing the chance of seeing decays. Details of equipment and…

  2. A Sensitive Cloud Chamber without Radioactive Sources

    Science.gov (United States)

    Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

    2012-01-01

    We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given. (Contains 8 figures.)

  3. 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...

  4. 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 cond...

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

    Science.gov (United States)

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

    2016-12-13

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

  6. Experimental biomass burning emission assessment by combustion chamber

    Science.gov (United States)

    Lusini, Ilaria; Pallozzi, Emanuele; Corona, Piermaria; Ciccioli, Paolo; Calfapietra, Carlo

    2014-05-01

    Biomass burning is a significant source of several atmospheric gases and particles and it represents an important ecological factor in the Mediterranean ecosystem. In this work we describe the performances of a recently developed combustion chamber to show the potential of this facility in estimating the emission from wildland fire showing a case study with leaves, small branches and litter of two representative species of Mediterranean vegetation, Quercus pubescens and Pinus halepensis. The combustion chamber is equipped with a thermocouple, a high resolution balance, an epiradiometer, two different sampling lines to collect organic volatile compounds (VOCs) and particles, a sampling line connected to a Proton Transfer Reaction Mass-Spectrometer (PTR-MS) and a portable analyzer to measure CO and CO2 emission. VOCs emission were both analyzed with GC-MS and monitored on-line with PTR-MS. The preliminary qualitative analysis of emission showed that CO and CO2 are the main gaseous species emitted during the smoldering and flaming phase, respectively. Many aromatics VOCs as benzene and toluene, and many oxygenated VOC as acetaldehyde and methanol were also released. This combustion chamber represents an important tool to determine the emission factor of each plant species within an ecosystem, but also the contribution to the emissions of the different plant tissues and the kinetics of different compound emissions during the various combustion phases. Another important feature of the chamber is the monitoring of the carbon balance during the biomass combustion.

  7. Chamber B Thermal/Vacuum Chamber: User Test Planning Guide

    Science.gov (United States)

    Montz, Mike E.

    2012-01-01

    Test process, milestones and inputs are unknowns to first-time users of Chamber B. The User Test Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their test engineering personnel in test planning and execution. Material covered includes a roadmap of the test process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, test article interfaces, and inputs necessary to define test scope, cost, and schedule are included as an appendix to the guide.

  8. Effect of flue gas composition on deposit induced high temperature corrosion under laboratory conditions mimicking biomass firing. Part I: Exposures in oxidizing and chlorinating atmospheres

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Kiamehr, Saeed; Montgomery, Melanie

    2017-01-01

    In biomass fired power plants, deposition of alkali chlorides on superheaters, aswell as the presence of corrosive flue gas species, give rise to fast corrosion ofsuperheaters. In order to understand the corrosion mechanism under thiscomplex condition, the influence of the flue gas composition...... bothoxidizing and oxidizing-chlorinating atmospheres, and the resulting corrosionproducts were comprehensively studied with scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD)techniques. The results show that deposit-free samples suffer grain boundaryattack...... only in an oxidizing-chlorinating atmosphere, otherwise corrosionresults in formation of a duplex oxide. Corrosion attack on deposit-coatedsamples was higher than on deposit-free samples irrespective of the gaseousatmosphere. Specifically, severe volatilization of alloying elements occurred ondeposit...

  9. Effects of long term exposure to hydrogen fluoride on grapevines

    Energy Technology Data Exchange (ETDEWEB)

    Murray, F.

    1984-01-01

    Grapevines Vitis vinifera L. Shiraz were exposed to hydrogen fluoride in open-top chambers for 189 days at mean atmospheric fluoride concentrations of 0.27, 0.17 or 0.07 ..mu..g HFm/sup -3/. Grapevines growing under ambient conditions outside the chambers were exposed to a mean atmospheric fluoride concentration of 0.08 ..mu..g HFm/sup -3/. The maximum leaf fluoride concentrations associated with these treatments were 62, 27, 9 and 15 ..mu..g Fg/sup -1/, respectively. Foliar necrosis was first observed on grapevines exposed to 0.27 and 0.17 ..mu..g HFm/sup -3/ after 83 and 99 days, respectively. Exposure to fluoride increased the fluoride content of berries and peduncles, and reduced leaf chlorophyll a and total chlorophyll concentration at both mid-season and harvest. Exposure to 0.17 ..mu..g HF m/sup -3/ was associated with higher total acid content of grapes than other treatments. Fluoride had no significant effect on bunch weight, number of bunches, grape yield, grape water or potential alcohol content, leaf chlorophyll b or leaf protein concentration. The high accumulation of fluoride in peduncles, but low fluoride accumulation in berries, suggests that the peduncle acts to block the translocation of fluoride from sites of uptake to the fruit. 42 references, 1 figure, 5 tables.

  10. 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...

  11. Differing response of asthmatics to sulfur dioxide exposure with continuous and intermittent exercise

    Energy Technology Data Exchange (ETDEWEB)

    Kehrl, H.R.; Roger, L.J.; Hazucha, M.J.; Horstman, D.H.

    1986-08-29

    Ten mild asthmatics were initially exposed in an environmental chamber (26 C, 70% RH) to clean air and 1.0 ppm sulfur dioxide while performing three sets of 10 minutes treadmill exercise (ventilation = 41 1/min) and 15 minutes rest. To evaluate the effects of the pattern and duration of exercise on the response to sulfur dioxide exposure, the subjects were then exposed to the same environmental conditions, while exercising continuously for 30 minutes. Specific airways resistance (SRaw) was measured by body plethysmography prior to exposures and after each exercise. All SRaw responses with sulfur dioxide exposure were significantly different than the clean air responses. It appears that asthmatics show an attenuated response to repetitive exercise in a 1.00 ppm sulfur dioxide atmosphere and that the response to sulfur dioxide exposure develops rapidly and is maintained during 30 minutes continuous exercise.

  12. A silicon microstrip gas chamber

    Energy Technology Data Exchange (ETDEWEB)

    Van der Marel, J. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Van den Bogaard, A. (Delft Inst. of Microelectronics and Submicrotechnology, Delft Univ. of Tech. (Netherlands)); Van Eijk, C.W.E. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Hollander, R.W. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Okx, W.J.C. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Sarro, P.M. (Delft Inst. of Microelectronics and Submicrotechnology, Delft Univ. of Tech. (Netherlands))

    1994-09-01

    We are manufacturing microstrip gas chambers (MSGC) on silicon with an insulating SiO[sub 2] layer. To study the effect of the sheet resistance of the SiO[sub 2] on the operation of the detector several processes to modify the SiO[sub 2] layer have been investigated: ion implantation, boron and phosphorus diffusion, phosphosilicate glass evaporation and polycrystalline silicon deposition. The dependence of the gas gain on the potentials of the different electrodes and the long term stability have been studied. ((orig.))

  13. Detecting special nuclear material using a neutron time projection chamber

    Science.gov (United States)

    Carosi, G.; Bernstein, A.; Bowden, N.; Burke, J.; Carter, D.; Foxe, M.; Heffner, M.; Jovanovic, I.; Mintz, J.; O'Malley, P.

    2010-02-01

    Time projection chambers are 3-dimensional charged particle cameras based on drifting ionization tracks at a known velocity onto an electronic readout plane. These instruments are capable of detecting fast neutrons which are unique signatures of special nuclear material with low natural background rates. Here we describe a neutron Time Projection Chamber (nTPC) developed at Lawrence Livermore National Laboratory (LLNL) which has demonstrated directional sensitivity to fission neutrons along with high rejection of background gamma-ray and electron events. Using a combination hydrogen/methane drift gas at several atmospheres we've demonstrated the ability to point to a Cf-252 source simulating 6kg of weapons grade plutonium at 10's of meters with one hour integration time. Plans for future field deployable devices will also be outlined. )

  14. Simulation of space charge effects in resistive plate chambers

    CERN Document Server

    Lippmann, Christian

    2003-01-01

    Multigap resistive plate chambers with 0.3-mm gas gaps operated in avalanche mode at atmospheric pressure have reached timing accuracies below 50 ps (standard deviation) with efficiencies above 99% . The avalanches in high homogeneous electric fields of 100 kV/cm are strongly influenced by space charge effects which are the main topic of this paper. We extend a previously discussed Monte Carlo simulation model of avalanches in resistive plate chambers by the dynamic calculation of the electric field in the avalanches. We complete the previously presented results on time resolution and efficiency data with simulated charge spectra. The simulated data shows good agreement with measurements. The detailed simulation of the avalanche saturation due to the space charge fields explains the small observed charges, the shape of the spectra, and the linear increase of average charges with high voltage. (22 refs).

  15. Pupillary block glaucoma following implantation of a posterior chamber pseudophakos in the anterior chamber.

    Directory of Open Access Journals (Sweden)

    Mandal Anil

    2002-01-01

    Full Text Available Pupillary block glaucoma is a common complication of cataract surgery, especially following anterior chamber intraocular lens implantation. We report a case of pupillary block glaucoma with a posterior chamber IOL that was implanted in the anterior chamber following a complicated extracapsular cataract extraction. The case was successfully managed by explantation of the posterior chamber lens, anterior vitrectomy, peripheral iridectomy and secondary anterior chamber intraocular lens implantation. The intraocular pressure was controlled with a single topical antiglaucoma medication.

  16. Effects of long-term elevated atmospheric CO{sub 2} concentrations on Pinus ponderosa

    Energy Technology Data Exchange (ETDEWEB)

    Surano, K.A.; Kercher, J.R. [eds.

    1993-10-01

    This report details the results from an experiment of the effects of long-term elevated atmospheric CO{sub 2} concentrations on ponderosa pine (Pinus ponderosa Laws.) saplings and seedlings. The study began in 1983 as a pilot study designed to explore the feasibility of using open-top chambers for continuous multi-year exposures on sapling-sized trees and to examine possible CO{sub 2} responses so that future research could be adequately designed. however, following the first year of exposure, preliminary results from the study indicated that measurements of CO{sub 2} responses should be intensified. Open-top chambers proved suitable for use in multiyear exposures of mature trees. With respect to the preliminary examination of CO{sub 2} responses, many interesting observations were made. The nature of the preliminary results suggests that future long-term field CO{sub 2} exposures on perennial species may be critical to the understanding and preparation for future environments. Other research reported here attempted to adapt an existing western coniferous forest growth and succession model for use in elevated CO{sub 2} scenarios using differential species responses, and assessed the usefulness of the model in that regard. Seven papers have been processed separately for inclusion in the appropriate data bases.

  17. Effect of flue gas composition on deposit induced high temperature corrosion under laboratory conditions mimicking biomass firing. Part II: Exposures in SO2 containing atmospheres

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Kiamehr, Saeed; Montgomery, Melanie

    2017-01-01

    In biomass fired power plants, the fast corrosion of superheaters is facilitatedby the presence of corrosive flue gas species, for example, SO2, which arereleased during combustion. To understand the role of the gas species on thecorrosion process, comparative laboratory exposures of deposit (KCl......)-coatedand deposit-free austenitic stainless steel (TP 347H FG) samples to gas mixturescontaining SO2 was carried out, under conditions relevant to biomass-firing.Exposures were conducted isothermally at 560 8C for 72 h, in oxidizingsulphidizing,and oxidizing-sulphidizing-chlorinating gas mixtures containing60 ppmv...... SO2. Scanning electron microscopy (SEM), energy dispersive X-rayspectroscopy (EDS) and X-ray diffraction (XRD) techniques werecomplimentarily applied to characterize the resulting corrosion products. Apartially molten K2SO4-layer formed on KCl coated specimens, and corrosionresulted in localized...

  18. Effect of flue gas composition on deposit induced high temperature corrosion under laboratory conditions mimicking biomass firing. Part II: Exposures in SO2 containing atmospheres

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Kiamehr, Saeed; Montgomery, Melanie

    2017-01-01

    )-coatedand deposit-free austenitic stainless steel (TP 347H FG) samples to gas mixturescontaining SO2 was carried out, under conditions relevant to biomass-firing.Exposures were conducted isothermally at 560 8C for 72 h, in oxidizingsulphidizing,and oxidizing-sulphidizing-chlorinating gas mixtures containing60 ppmv......In biomass fired power plants, the fast corrosion of superheaters is facilitatedby the presence of corrosive flue gas species, for example, SO2, which arereleased during combustion. To understand the role of the gas species on thecorrosion process, comparative laboratory exposures of deposit (KCl...... broad pits containing sulphides and oxides. The severepitting attack was decreased by the presence of HCl in the gas mixture....

  19. Germination and growth of lettuce (Lactuca sativa) at low atmospheric pressure

    Science.gov (United States)

    Spanarkel, Robert; Drew, Malcolm C.

    2002-01-01

    The response of lettuce (Lactuca sativa L. cv. Waldmann's Green) to low atmospheric pressure was examined during the initial 5 days of germination and emergence, and also during subsequent growth to vegetative maturity at 30 days. Growth took place inside a 66-l-volume low pressure chamber maintained at 70 kPa, and plant response was compared to that of plants in a second, matching chamber that was at ambient pressure (approximately 101 kPa) as a control. In other experiments, to determine short-term effects of low pressure transients, plants were grown at ambient pressure until maturity and then subjected to alternating periods of 24 h of low and ambient atmospheric pressures. In all treatments the partial pressure of O2 was maintained at 21 kPa (approximately the partial pressure in air at normal pressure), and the partial pressure of CO2 was in the range 66.5-73.5 Pa (about twice that in normal air) in both chambers, with the addition of CO2 during the light phase. With continuous exposure to low pressure, shoot and root growth was at least as rapid as at ambient pressure, with an overall trend towards slightly greater performance at the lower pressure. Dark respiration rates were greater at low pressure. Transient periods at low pressure decreased transpiration and increased dark respiration but only during the period of exposure to low pressure. We conclude that long-term or short-term exposure to subambient pressure (70 kPa) was without detectable detriment to vegetative growth and development.

  20. Estimation of exposure to atmospheric pollutants during pregnancy integrating space-time activity and indoor air levels: does it make a difference?

    Science.gov (United States)

    Marion, OUIDIR; Lise, GIORGIS-ALLEMAND; Sarah, LYON-CAEN; Xavier, MORELLI; Claire, CRACOWSKI; Sabrina, PONTET; Isabelle, PIN; Johanna, LEPEULE; Valérie, SIROUX; Rémy, SLAMA

    2016-01-01

    Studies of air pollution effects during pregnancy generally only consider exposure in the outdoor air at the home address. We aimed to compare exposure models differing in their ability to account for the spatial resolution of pollutants, space-time activity and indoor air pollution levels. We recruited 40 pregnant women in the Grenoble urban area, France, who carried a Global Positioning System (GPS) during up to 3 weeks; in a subgroup, indoor measurements of fine particles (PM2.5) were conducted at home (n=9) and personal exposure to nitrogen dioxide (NO2) was assessed using passive air samplers (n=10). Outdoor concentrations of NO2, and PM2.5 were estimated from a dispersion model with a fine spatial resolution. Women spent on average 16 h per day at home. Considering only outdoor levels, for estimates at the home address, the correlation between the estimate using the nearest background air monitoring station and the estimate from the dispersion model was high (r=0.93) for PM2.5 and moderate (r=0.67) for NO2. The model incorporating clean GPS data was less correlated with the estimate relying on raw GPS data (r=0.77) than the model ignoring space-time activity (r=0.93). PM2.5 outdoor levels were not to moderately correlated with estimates from the model incorporating indoor measurements and space-time activity (r=−0.10 to 0.47), while NO2 personal levels were not correlated with outdoor levels (r=−0.42 to 0.03). In this urban area, accounting for space-time activity little influenced exposure estimates; in a subgroup of subjects (n=9), incorporating indoor pollution levels seemed to strongly modify them. PMID:26300245

  1. New indoor environment chambers and field experiment offices for research on human comfort, health and productivity

    DEFF Research Database (Denmark)

    Toftum, Jørn; Langkilde, Gunnar; Fanger, Povl Ole

    2004-01-01

    The article describes three new indoor environment chambers, a new laboratory for the study of air movement in spaces and five offices for controlled environment exposures of human subjects in field experiments at the International Centre for Indoor Environment and Energy, Technical University of...... of Denmark. Together with three older chambers, the Centre now has at its disposal 12 spaces for studying indoor environments and their impact on human comfort, health and productivity....

  2. Limits to Drift Chamber Resolution

    CERN Document Server

    Riegler, Werner

    1998-01-01

    ATLAS (A Large Toroidal LHC Apparatus) will be a general-purpose experiment at the Large Hadron Collider that will be operational at CERN in the year 2004. The ATLAS muon spectrometer aims for a momentum resolution of 10% for a transverse momentum of pT=1TeV. The precision tracking devices in the muon system will be high pressure drift tubes (MDTs) with a single wire resolution of 1100 chambers covering an area of ≈ 2500m2. The high counting rates in the spectrometer as well as the aim for excellent spatial resolution and high efficiency put severe constraints on the MDT operating parameters. This work describes a detailed study of all the resolution limiting factors in the ATLAS environment. A ’full chain’ simulation of the MDT response to photons and charged particles as well as quantitative comparisons with measurements was performed. The good agreement between simulation and measurements resulted in a profound understanding of the drift chamber processes and the individual contributions to the spat...

  3. Physicist makes muon chamber sing

    CERN Document Server

    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...

  4. Systemic immunotoxicity in AJ mice following 6-month whole body inhalation exposure to diesel exhaust.

    Science.gov (United States)

    Burchiel, Scott W; Lauer, Fredine T; McDonald, Jacob D; Reed, Matthew D

    2004-05-01

    The purpose of these studies was to determine the effects of subchronic diesel exposure on indicators of systemic immunity in mice. AJ mice were exposed daily for 6 months (6 h/day) to atmospheres containing one of four concentrations (30, 100, 300, and 1000 microg/m(3)) of diluted diesel exhaust (DE) in whole body exposure chambers. The effects of DE were compared to chamber exposure controls receiving fresh air. DE was assessed for effects on systemic immunity by measuring the proliferative response of spleen cells following stimulation with T cell (phytohemagglutinin, or PHA) or B cell (lipopolysaccharide, or LPS) mitogens. The results showed that DE at all exposure levels suppressed the proliferative response of T cells. B cell proliferation was increased at 30 microg/m(3) and was unaffected at the 100, 300, and 1000 microg/m(3) exposures. Polycyclic aromatic hydrocarbons (PAHs) are known to suppress spleen cell mitogenic responses, and it has been hypothesized by several groups that PAHs and perhaps benzo(a)pyrene (BaP)-quinones (BPQs) may be responsible for the effects of DE or diesel exhaust particles (DEP). Therefore, a second purpose of these studies was to determine the effects of in vitro BPQs on AJ mouse spleen cell mitogenic responses and compare to DE in preliminary studies. Unlike DE, BPQs were found to increase T cell proliferation. In addition, analysis of chamber atmospheres showed that there was little if any PAH and BPQs in DE. Therefore, these results demonstrate that because of the absence of BPQs in DE, they are likely not responsible for the immunosuppressive effect of DE on murine spleen cell responses.

  5. Enclosed Chambers for Humidity Control And Sample Containment in Fiber Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, M.; Kendall, A.; Tanaka, M.; Weissman, J.S.; Stubbs, G.

    2009-05-26

    A chamber and stretch frame for making fibers for diffraction is described. The chamber is made from a simple plastic cuvette with silicon nitride windows. It is suitable for maintaining constant humidity during fiber drying and data collection, and allows stretching of the fiber and exposure to magnetic fields during sample preparation. If necessary, it provides primary containment for toxic and infectious biological materials. The chamber has been used in fiber diffraction experiments with filamentous plant viruses and a yeast prion protein, and is shown to produce excellent orientation and to maintain hydration and order at the molecular level.

  6. Enclosed chambers for humidity control and sample containment in fiber diffraction

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, M.; Kendall, A.; Tanaka, M.; Weissman, J.S.; Stubbs, G. (Vanderbilt); (HHMI)

    2008-11-03

    A chamber and stretch frame for making fibers for diffraction is described. The chamber is made from a simple plastic cuvette with silicon nitride windows. It is suitable for maintaining constant humidity during fiber drying and data collection, and allows stretching of the fiber and exposure to magnetic fields during sample preparation. If necessary, it provides primary containment for toxic and infectious biological materials. The chamber has been used in fiber diffraction experiments with filamentous plant viruses and a yeast prion protein, and is shown to produce excellent orientation and to maintain hydration and order at the molecular level.

  7. Atmospheric Dispositifs

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2015-01-01

    Through the coupling of dispositif with atmosphere this paper engages in a discussion of the atmospherics as both a form of knowledge and a material practice. In doing so the objective is to provide an inventory of tools and methodologies deployed in the construction of atmosphere understood......, the conceptual foundations and protocols for the production of atmosphere in architecture might be found beneath the surface of contemporary debates. In this context, the notion of atmospheric dispositif – illustrated through an oeuvre of the German architect Werner Ruhnau and its theoretical and historical...

  8. Transferring calibration coefficients from ionisation chambers used for diagnostic radiology to transmission chambers.

    Science.gov (United States)

    Yoshizumi, Maíra T; Caldas, Linda V E

    2012-07-01

    In this work, the response of a double volume transmission ionisation chamber, developed at the Instituto de Pesquisas Energéticas e Nucleares, was compared to that of a commercial transmission chamber. Both ionisation chambers were tested in different X-ray beam qualities using secondary standard ionisation chambers as reference dosimeters. These standard ionisation chambers were a parallel-plate and a cylindrical ionisation chambers, used for diagnostic radiology and mammography beam qualities, respectively. The response of both transmission chambers was compared to that of the secondary standard chambers to obtain coefficients of equivalence. These coefficients allow the transmission chambers to be used as reference equipment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Atmospheric Gas-Phase Reactions of Fluorinated Compounds and Alkenes

    DEFF Research Database (Denmark)

    Østerstrøm, Freja From

    for Atmospheric Research, Denmark. All setups consist of a chamber and uses UV light to initiate the experiments and Fourier transform infrared spectroscopy for the analysis of the data. The atmospheric chemistry of new chlorofluorocarbon replacements is discussed. Experimental studies have been performed on: (CF......Experimental studies have been performed using three different smog chamber setups to investigate the atmospheric chemistry of fluorinated compounds as well as alkenes. The three instruments were at Ford Motor Company, USA, National Center for Atmospheric Research, USA, and Copenhagen Center...

  10. Dependence with air density of the response of the PTW SourceCheck ionization chamber for low energy brachytherapy sources.

    Science.gov (United States)

    Tornero-López, Ana M; Guirado, Damián; Perez-Calatayud, Jose; Ruiz-Arrebola, Samuel; Simancas, Fernando; Gazdic-Santic, Maja; Lallena, Antonio M

    2013-12-01

    Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is corrected to standard atmospheric conditions using the usual temperature and pressure correction factor. Nevertheless, when assessing low energy sources, the ionization chambers may not fulfill that condition and a residual density dependence still remains after correction. In this work, the authors examined the behavior of the PTW 34051 SourceCheck ionization chamber when measuring the air kerma strength of (125)I seeds. Four different SourceCheck chambers were analyzed. With each one of them, two series of measurements of the air kerma strength for (125)I selectSeed(TM) brachytherapy sources were performed inside a pressure chamber and varying the pressure in a range from 747 to 1040 hPa (560 to 780 mm Hg). The temperature and relative humidity were kept basically constant. An analogous experiment was performed by taking measurements at different altitudes above sea level. Contrary to other well-known ionization chambers, like the HDR1000 PLUS, in which the temperature-pressure correction factor overcorrects the measurements, in the SourceCheck ionization chamber they are undercorrected. At a typical atmospheric situation of 933 hPa (700 mm Hg) and 20 °C, this undercorrection turns out to be 1.5%. Corrected measurements show a residual linear dependence on the density and, as a consequence, an additional density dependent correction must be applied. The slope of this residual linear density dependence is different for each SourceCheck chamber investigated. The results obtained by taking measurements at different altitudes are compatible with those obtained with the pressure chamber. Variations of the altitude and changes in the weather conditions may produce

  11. Automation of soil flux chamber measurements: potentials and pitfalls

    Science.gov (United States)

    Görres, Carolyn-Monika; Kammann, Claudia; Ceulemans, Reinhart

    2016-03-01

    time the detection of disturbed chamber measurements during nights with a stratified atmosphere, resulting in unbiased nighttime SR estimates. Thus besides providing high temporal frequency flux data, automated chamber systems offer another possibility to greatly improve our understanding of SR fluxes.

  12. Effect of flue gas composition on deposit induced high temperature corrosion under laboratory conditions mimicking biomass firing. Part I: Exposures in oxidizing and chlorinating atmospheres

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Kiamehr, Saeed; Montgomery, Melanie

    2017-01-01

    In biomass fired power plants, deposition of alkali chlorides on superheaters, aswell as the presence of corrosive flue gas species, give rise to fast corrosion ofsuperheaters. In order to understand the corrosion mechanism under thiscomplex condition, the influence of the flue gas composition...... on hightemperature corrosion of an austenitic superheater material under laboratoryconditions mimicking biomass firing is investigated in this work. Exposuresinvolving deposit (KCl)-coated and deposit-free austenitic stainless steel (TP347H FG) samples were conducted isothermally at 560 8C for 72 h, under...... only in an oxidizing-chlorinating atmosphere, otherwise corrosionresults in formation of a duplex oxide. Corrosion attack on deposit-coatedsamples was higher than on deposit-free samples irrespective of the gaseousatmosphere. Specifically, severe volatilization of alloying elements occurred ondeposit...

  13. Studies in Atmospheric Chemistry. I. Assessing Exposure to Environmental Tobacco Smoke. I. Sulfur Oxides Chemistry Related to PM(10) Formation and Visibility Degradation

    Science.gov (United States)

    Caka, Fern M.

    I. Data from four DC-10 flights and forty-eight DC-9 flights are used to evaluate a model which predicts concentrations of ETS onboard commercial aircraft. A first order rate of penetration (decay) is shown to predict concentrations well. II. Two studies were conducted in Utah Valley and the Grand Canyon region. Annular diffusion denuders, impingers and real-time instruments were used to collect and measure sulfur oxide and nitrogen oxide species, ammonia, particulate acidity, and various oxidants. The data provided information on the distribution between gas and particulate phase species as a function of time, location and meteorology. Trends in the data sets which shed light on the factors which may contribute to atmospheric particulate conversion and the effect on PM_{10} formation and visibility degradation are presented.

  14. The risk of leukaemia in young children from exposure to tritium and carbon-14 in the discharges of German nuclear power stations and in the fallout from atmospheric nuclear weapons testing

    Energy Technology Data Exchange (ETDEWEB)

    Wakeford, Richard [The University of Manchester, Centre for Occupational and Environmental Health, Institute of Population Health, Manchester (United Kingdom)

    2014-05-15

    Towards the end of 2007, the results were published from a case-control study (the ''KiKK Study'') of cancer in young children, diagnosed <5 years of age during 1980-2003 while resident near nuclear power stations in western Germany. The study found a tendency for cases of leukaemia to live closer to the nearest nuclear power station than their matched controls, producing an odds ratio that was raised to a statistically significant extent for residence within 5 km of a nuclear power station. The findings of the study received much publicity, but a detailed radiological risk assessment demonstrated that the radiation doses received by young children from discharges of radioactive material from the nuclear reactors were much lower than those received from natural background radiation and far too small to be responsible for the statistical association reported in the KiKK Study. This has led to speculation that conventional radiological risk assessments have grossly underestimated the risk of leukaemia in young children posed by exposure to man-made radionuclides, and particular attention has been drawn to the possible role of tritium and carbon-14 discharges in this supposedly severe underestimation of risk. Both {sup 3}H and {sup 14}C are generated naturally in the upper atmosphere, and substantial increases in these radionuclides in the environment occurred as a result of their production by atmospheric testing of nuclear weapons during the late 1950s and early 1960s. If the leukaemogenic effect of these radionuclides has been seriously underestimated to the degree necessary to explain the KiKK Study findings, then a pronounced increase in the worldwide incidence of leukaemia among young children should have followed the notably elevated exposure to {sup 3}H and {sup 14}C from nuclear weapons testing fallout. To investigate this hypothesis, the time series of incidence rates of leukaemia among young children <5 years of age at diagnosis has been

  15. The risk of leukaemia in young children from exposure to tritium and carbon-14 in the discharges of German nuclear power stations and in the fallout from atmospheric nuclear weapons testing.

    Science.gov (United States)

    Wakeford, Richard

    2014-05-01

    Towards the end of 2007, the results were published from a case-control study (the "KiKK Study") of cancer in young children, diagnosed nuclear power stations in western Germany. The study found a tendency for cases of leukaemia to live closer to the nearest nuclear power station than their matched controls, producing an odds ratio that was raised to a statistically significant extent for residence within 5 km of a nuclear power station. The findings of the study received much publicity, but a detailed radiological risk assessment demonstrated that the radiation doses received by young children from discharges of radioactive material from the nuclear reactors were much lower than those received from natural background radiation and far too small to be responsible for the statistical association reported in the KiKK Study. This has led to speculation that conventional radiological risk assessments have grossly underestimated the risk of leukaemia in young children posed by exposure to man-made radionuclides, and particular attention has been drawn to the possible role of tritium and carbon-14 discharges in this supposedly severe underestimation of risk. Both (3)H and (14)C are generated naturally in the upper atmosphere, and substantial increases in these radionuclides in the environment occurred as a result of their production by atmospheric testing of nuclear weapons during the late 1950s and early 1960s. If the leukaemogenic effect of these radionuclides has been seriously underestimated to the degree necessary to explain the KiKK Study findings, then a pronounced increase in the worldwide incidence of leukaemia among young children should have followed the notably elevated exposure to (3)H and (14)C from nuclear weapons testing fallout. To investigate this hypothesis, the time series of incidence rates of leukaemia among young children nuclear weapons testing, or that incidence rates are related to level of exposure to fallout, is apparent from these

  16. Tests of anechoic chamber for aeroacoustics investigations

    Science.gov (United States)

    Palchikovskiy, V. V.; Bersenev, Yu. V.; Makashov, S. Yu.; Belyaev, I. V.; Korin, I. A.; Sorokin, E. V.; Khramtsov, I. V.; Kustov, O. Yu.

    2016-10-01

    The paper presents the results of qualification tests in the new anechoic chamber of Perm National Research Polytechnic University (PNRPU) built in 2014-2015 and evaluation of the chamber quality in aeroacoustic experiments. It describes design features of the chamber and its sound-absorption lining. The qualification tests were carried out with tonal and broadband noise sources in the frequency range 100 Hz - 20 kHz for two different cases of the source arrangement. In every case, measurements were performed in three directions by traverse microphones. Qualification tests have determined that in the chamber there is a free acoustic field within radius of 2 m for tonal noise and 3 m for broadband noise. There was also evaluated acoustic quality of the chamber by measurements of the jet noise and vortex ring noise. The results of the experiments demonstrate that PNRPU anechoic chamber allows the aeroacoustic measurements to be performed to obtain quantitative results.

  17. 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.

  18. Time Projection Chamber at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D.; Leitch, M.; Navon, I.; Numao, T.; Schlatter, P.; Dixit, M.S.; Hargrove, C.K.; Mes, H.; Bennett, A.; Macdonald, J.A.

    1984-01-01

    The Time Projection Chamber at TRIUMF is being used to search for muon-electron conversion. The best spatial resolution in the TPC, sigma approx. = 200 ..mu..m, occurs at the minimum drift length and for an optimum track-to-anode crossing angle determined by the magnetic field. The observed resolution is dependent on the diffusion of the drifting electrons, the track-to-anode crossing angle, vector E X vector B effects near the anode wire and the discrete nature of the ionization process. Distortion due to positive ions leaking back into the drift volume from the anode wire region have been nearly eliminated by the use of a pulsed dual grid system.

  19. Development and construction of a specific chamber for phototoxicity test

    Energy Technology Data Exchange (ETDEWEB)

    Sufi, Bianca S.; Mathor, Monica B., E-mail: biancasufi@usp.br, E-mail: mathor@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Esteves-Pedro, Natalia M.; Kaneko, Telma Mary, E-mail: nataliamenves@yahoo.com.br, E-mail: tsakuda@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Fac. de Ciencias Farmaceuticas; Lopes, Patricia, E-mail: patricia.lopes@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil)

    2013-07-01

    Phototoxicity corresponds to the acute toxic response induced after skin exposure 'in vivo' and 'ex vivo' to certain chemicals and subsequent exposure to irradiation. Phototoxicity 'in vitro' assay is determined by viability of fibroblasts BALB/c 3T3 exposed to chemicals in the presence and absence of light. Substances identified as phototoxic are susceptible to 'in vivo' phototoxicity (OECD 432, 2004). A chamber was developed and constructed according to the guidelines OECD Toxicity Guide - 432 and ®ECVAM DB-ALM: INVITTOX N. 78. The chamber was built in stainless steel frame, with UVA lamps and dark area for negative control. The tests to qualify the chamber were performed with Sodium Lauryl Sulfate, recommended by the guides aforementioned, as negative control; and Bergamot oil (Givaudan-Roche), as positive control. Bergamot, Citrus bergamia, has, as major component, Bergapten responsible for its photosensitive activity. Both samples were diluted in Phosphate Buffered Saline with concentrations between 0.005 and 0.1 mg/mL, which were calculated by the dilution factor 1.47. These tests were performed over fibroblast BALB/c 3T3 culture and submitted to phototoxicity assay with MTS dye, under spectrophotometric reading, which allows determining the Photo Irritation Factor (PIF), what suggests that a substance with a PIF<2 predicts no phototoxicity; PIF>2 and <5 provides likely phototoxicity and PIF>5 provides phototoxicity. Sodium Lauryl Sulfate presented a PIF=1, being in accordance with the OECD. Bergamot oil has shown to be likely phototoxic with a PIF=2,475. These results provide that the chamber is qualified to be used to perform phototoxicity tests with assurance and security. (author)

  20. 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).

  1. Drift chamber tracking with neural networks

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 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.

  3. Anechoic chamber for VHF and UHF bands

    Science.gov (United States)

    Morikawa, Takao; Sugiura, Akira; Harima, Katsushige; Masuzawa, Hiroshi

    1995-06-01

    Built in 1969, the anechoic chamber of CRL has been used to the fullest by researchers in many fields such as EMI, EMC, antenna design, standard of electric field intensity, and type approval testing. In particular, in the early days of space development in Japan, many satellite-born antennas were developed in this anechoic chamber. However, a quarter of a century has passed since its construction and deteriorated performance due to superannuation sometimes caused difficulties in experiments conducted in the chamber. In 1993, CRL constructed a Measuring Facility for Radio Research (MFRR) and the anechoic chamber for VHF-UHF bands was remodeled as one of the sub-facilities of MFRR. The remodeling work included full replacement of the electromagnetic shielding, absorbers and measurement system. Since the remodeled anechoic chamber is being used not only for EMI tests but also for other purposes, a full-anechoic chamber has been adopted. In addition the chamber has been designed for the frequency range between 30 MHz and 10 GHz. After the remodeling work, the performance of the chamber is greatly improved. The average shielding factor is better than 85 dB for all frequency ranges and the unwanted reflection characteristic is -30 dB for frequencies above 1 GHZ. This paper summarizes the remodeling work, and the specifications and performance of the remodeled anechoic chamber.

  4. 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...

  5. D0 Central Tracking Chamber Performance Studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, Domenico [State Univ. of New York (SUNY), Stony Brook, NY (United States)

    1991-01-01

    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 $R\\Phi$ 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 $\\gamma \\to e^+ e^-$ events.

  6. The Mark II Vertex Drift Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, J.P.; Baggs, R.; Fujino, D.; Hayes, K.; Hoard, C.; Hower, N.; Hutchinson, D.; Jaros, J.A.; Koetke, D.; Kowalski, L.A.

    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 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 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{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.

  7. Biases in methane chamber measurements in peatlands

    Science.gov (United States)

    Juszczak, R.

    2013-03-01

    The paper presents results of CH4 emission measurements at peatland with the application of the dynamic chamber technique. The measurements were conducted in two types of chambers differing in shape, height, volume and technology used to assure their tightness. The study tested how the following factors: 1) forced chamber headspace mixing or its absence, 2) mistakes of the person conducting measurements, 3) improper application of linear technique for calculating CH4 fluxes, and 4) simulated air sampling typical for static chambers, influence the significance of errors and the underestimation rate of CH4 fluxes measured in situ. It was indicated that chamber headspace mixing allows estimating methane fluxes with a smaller error than in the case of measurements conducted without mixing, and CH4 fluxes in such conditions can be 47 to 58% higher (depending on the chamber type) than in a chamber without fans. Using dynamic chambers and a fast analyzer to measure methane fluxes allows shortening the methane measurement process to a few minutes. On the other hand, using static chambers for methane flux measurements may lead to 70% underestimation of the calculated flux.

  8. D0 central tracking chamber performance studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, Domenico [State Univ. of New York, Stony Brook, NY (United States)

    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.

  9. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily exper......” implications and qualities of the approach are identified through concrete examples of a design case, which also investigates the qualities and implications of addressing atmospheres both as design concern and user experience.......This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...... experience in space, presented as middle ground experience. In the field of HCI, middle ground experiences complete the unarticulated spectrum between designing for foreground of attention or background awareness. When “Articulating Atmospheres through Middle Ground Experiences in Interaction Design...

  10. Co-ordination in morphological leaf traits of early diverging angiosperms is maintained following exposure to experimental palaeo-atmospheric conditions of sub-ambient O2 and elevated CO2

    Directory of Open Access Journals (Sweden)

    Christiana Evans-Fitz.Gerald

    2016-09-01

    Full Text Available In order to be successful in a given environment a plant should invest in a vein network and stomatal distribution that ensures balance between both water supply and demand. Vein density (Dv and stomatal density (SD have been shown to be strongly positively correlated in response to a range of environmental variables in more recently evolved plant species, but the extent of this relationship has not been confirmed in earlier diverging plant lineages. In order to examine the effect of a changing atmosphere on the relationship between Dv and SD, five early-diverging plant species representing two different reproductive plant grades were grown for seven months in a palaeo-treatment comprising an O2:CO2 ratio that has occurred multiple times throughout plant evolutionary history. Results show a range of species-specific Dv and SD responses to the palaeo-treatment, however we show that the strong relationship between Dv and SD under modern ambient atmospheric composition is maintained following exposure to the palaeo-treatment. This suggests strong inter-specific co-ordination between vein and stomatal traits for our study species even under relatively extreme environmental change. This co-ordination supports existing plant function proxies that use the distance between vein endings and stomata (Dm to infer plant palaeo-physiology.

  11. A fast-freezing device with a retractable environmental chamber, suitable for kinetic cryo-electron microscopy studies.

    Science.gov (United States)

    Trachtenberg, S

    1998-09-01

    The design and construction of a fast-freezing device are described. A polycarbonate chamber, in which the humidity and temperature are controlled by microprocessors, slides on a robust chassis guided by ball or Teflon bushings. In its freezing position, the chamber rests on top of the cryogen vessel. The specimen is therefore frozen directly from the experimental conditions within the chamber without exposure to the external environment. After freezing, the chamber, but not the specimen, rises automatically, vacating space for handling the specimen. The chamber, the shutter, and the specimen are all driven pneumatically at an adjustable speed of up to approximately 10 m s-1 and coordinated by either pneumatic or electronic logical gates. Provisions are made for automatic blotting, spraying, and flashing. The chamber is compatible with a liquid nitrogen-cooled copper block assembly for impact (slam) freezing for freeze-substitution and freeze-fracture. Copyright 1998 Academic Press.

  12. Rising atmospheric CO{sub 2} and crops: Research methodology and direct effects

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, H. [National Soil Dynamics Laboratory, Auburn, AL (United States); Acock, B. [Systems Research Laboratory, Beltsville, MD (United States)

    1993-12-31

    Carbon dioxide is the food of trees and grass. Our relentless pursuit of a better life has taken us down a traffic jammed road, past smoking factories and forests. This pursuit is forcing a rise in the atmospheric CO{sub 2} level, and no one know when and if flood stage will be reached. Some thinkers have suggested that this increase of CO{sub 2} in the atmosphere will cause warming. No matter whether this prediction is realized or not, more CO{sub 2} will directly affect plants. Data from controlled observations have usually, but not always, shown benefits. Our choices of scientific equipment for gathering CO{sub 2} response data are critical since we must see what is happening through the eye of the instrument. The signals derived from our sensors will ultimately determine the truth of our conclusions, conclusion which will profoundly influence our policy decisions. Experimental gear is selected on the basis of scale of interest and problem to be addressed. Our imaginations and our budgets interact to set bounds on our objectives and approaches. Techniques run the gamut from cellular microprobes through whole-plant controlled environment chambers to field-scale exposure systems. Trade-offs exist among the various CO{sub 2} exposure techniques, and many factors impinge on the choice of a method. All exposure chambers are derivatives of three primary types--batch, plug flow, and continuous stirred tank reactor. Systems for the generation of controlled test atmospheres of CO{sub 2} vary in two basic ways--size and degree of control. Among the newest is free-air CO{sub 2} enrichment which allows tens of square meters of cropland to be studied.

  13. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  14. Atmospheric Neutrinos

    Directory of Open Access Journals (Sweden)

    Takaaki Kajita

    2012-01-01

    Full Text Available Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses atmospheric neutrino experiments and the neutrino oscillation studies with these neutrinos.

  15. Planetary Simulation Chambers bring Mars to laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Mateo-Marti, E.

    2016-07-01

    Although space missions provide fundamental and unique knowledge for planetary exploration, they are always costly and extremely time-consuming. Due to the obvious technical and economical limitations of in-situ planetary exploration, laboratory simulations are among the most feasible research options for making advances in planetary exploration. Therefore, laboratory simulations of planetary environments are a necessary and complementary option to expensive space missions. Simulation chambers are economical, more versatile, and allow for a higher number of experiments than space missions. Laboratory-based facilities are able to mimic the conditions found in the atmospheres and on the surfaces of a majority of planetary objects. Number of relevant applications in Mars planetary exploration will be described in order to provide an understanding about the potential and flexibility of planetary simulation chambers systems: mainly, stability and presence of certain minerals on Mars surface; and microorganisms potential habitability under planetary environmental conditions would be studied. Therefore, simulation chambers will be a promising tools and necessary platform to design future planetary space mission and to validate in-situ measurements from orbital or rover observations. (Author)

  16. Apollo 11 Facts Project [Spacecraft Retrieval and the Crew in the Anti-Contamination Chamber

    Science.gov (United States)

    1994-01-01

    Footage shows the launch of the Apollo 11 spacecraft and the retrieval of the module after reentering Earth's atmosphere and landing in the ocean (reentry and landing scenes not included). President Richard Nixon is seen greeting the crew of Apollo 11 while they are in the anti-contamination chamber.

  17. Wall Paint Exposure Assessment Model (WPEM)

    Science.gov (United States)

    WPEM uses mathematical models developed from small chamber data to estimate the emissions of chemicals from oil-based (alkyd) and latex wall paint which is then combined with detailed use, workload and occupancy data to estimate user exposure.

  18. 3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies

    Science.gov (United States)

    Shu, Anthony; Collette, Andrew; Drake, Keith; Grün, Eberhard; Horányi, Mihály; Kempf, Sascha; Mocker, Anna; Munsat, Tobin; Northway, Paige; Srama, Ralf; Sternovsky, Zoltán; Thomas, Evan

    2012-07-01

    A hypervelocity dust accelerator for studying micrometeorite impacts has been constructed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) at the University of Colorado. Based on the Max-Planck-Institüt für Kernphysik (MPI-K) accelerator, this accelerator is capable of emitting single particles of a specific mass and velocity selected by the user. The accelerator consists of a 3 MV Pelletron generator with a dust source, four image charge pickup detectors, and two interchangeable target chambers: a large high-vacuum test bed and an ultra-high vacuum impact study chamber. The large test bed is a 1.2 m diameter, 1.5 m long cylindrical vacuum chamber capable of pressures as low as 10-7 torr while the ultra-high vacuum chamber is a 0.75 m diameter, 1.1 m long chamber capable of pressures as low as 10-10 torr. Using iron dust of up to 2 microns in diameter, final velocities have been measured up to 52 km/s. The spread of the dust particles and the effect of electrostatic focusing have been measured using a long exposure CCD and a quartz target. Furthermore, a new technique of particle selection is being developed using real time digital filtering techniques. Signals are digitized and then cross-correlated with a shaped filter, resulting in a suppressed noise floor. Improvements over the MPI-K design, which include a higher operating voltage and digital filtering for detection, increase the available parameter space of dust emitted by the accelerator. The CCLDAS dust facility is a user facility open to the scientific community to assist with instrument calibrations and experiments.

  19. 3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Anthony; Horanyi, Mihaly; Kempf, Sascha; Thomas, Evan [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, Colorado 80303 (United States); Collette, Andrew; Drake, Keith; Northway, Paige [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, Colorado 80303 (United States); Gruen, Eberhard [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); MPI fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Mocker, Anna [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); MPI fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); IRS, Universitaet Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Munsat, Tobin [Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80303 (United States); Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Srama, Ralf [MPI fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); IRS, Universitaet Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); and others

    2012-07-15

    A hypervelocity dust accelerator for studying micrometeorite impacts has been constructed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) at the University of Colorado. Based on the Max-Planck-Instituet fuer Kernphysik (MPI-K) accelerator, this accelerator is capable of emitting single particles of a specific mass and velocity selected by the user. The accelerator consists of a 3 MV Pelletron generator with a dust source, four image charge pickup detectors, and two interchangeable target chambers: a large high-vacuum test bed and an ultra-high vacuum impact study chamber. The large test bed is a 1.2 m diameter, 1.5 m long cylindrical vacuum chamber capable of pressures as low as 10{sup -7} torr while the ultra-high vacuum chamber is a 0.75 m diameter, 1.1 m long chamber capable of pressures as low as 10{sup -10} torr. Using iron dust of up to 2 microns in diameter, final velocities have been measured up to 52 km/s. The spread of the dust particles and the effect of electrostatic focusing have been measured using a long exposure CCD and a quartz target. Furthermore, a new technique of particle selection is being developed using real time digital filtering techniques. Signals are digitized and then cross-correlated with a shaped filter, resulting in a suppressed noise floor. Improvements over the MPI-K design, which include a higher operating voltage and digital filtering for detection, increase the available parameter space of dust emitted by the accelerator. The CCLDAS dust facility is a user facility open to the scientific community to assist with instrument calibrations and experiments.

  20. Radiation exposure due to cosmic rays and solar X-ray photons at various atmospheric heights in aviation range over India

    Science.gov (United States)

    Palit, Sourav; Chakrabarti, Sandip Kumar; Bhattacharya, Arnab

    2016-07-01

    In this presentation we present our work on the continuous monitoring of radiation exposure in terms of effective dose rates, due to galactic cosmic rays (GCR) and solar X-rays at various altitudes within aviation range over India. As India belongs to equatorial region, there is negligible contribution from solar energetic particles (SEP). The calculation of cosmic ray counts as well as the solar X-ray photons are performed on the basis of the observation of various Dignity series balloon experiments on cosmic ray and solar high energy radiation studies, conducted by ICSP and Monte Carlo simulations performed with GEANT4 detector simulation software. The information on solar activity level from Geostationary Operational Environmental Satellite system (GOES) are employed in the calculations. A program, which is done entirely in MATLAB is employed to update regularly in a website, where we show images of dose rate (μSv) distribution over India at four different heights within the aviation range (updating at an interval of 30 minutes) and the approximate dose rates thats should be experienced by a pilot in an entire flight time between pairs of stations distributed all over India.

  1. Wide-band antennas for reverberation chambers

    NARCIS (Netherlands)

    Vogt-Ardatjew, R.A.; van de Beek, G.S.; Leferink, Frank Bernardus Johannes

    2012-01-01

    Shielding effectiveness measurements in a dual vibrating intrinsic reverberation chamber results in very repeatable results for a large frequency range and large dynamic range. Antennas in reverberation chambers do not need any gain, but the losses should be low and the dimensions should be small.

  2. 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

  3. 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...

  4. 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.

  5. Results from the MAC Vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    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 ..mu..m in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed.

  6. Validation of a fully anechoic chamber

    NARCIS (Netherlands)

    Mandaris, Dwi; Moonen, Dominicus Johannes Guilielmus; van de Beek, G.S.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2016-01-01

    This paper describes a technique to characterize the performance of a Fully Anechoic Chamber (FAC) from 500 MHz to 3 GHz based on S-Parameter analysis with antennas and a Vector Network Analyzer (VNA. The measurements have been performed by placing one antenna inside the chamber and performing S11

  7. 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...

  8. The HARP Time Projection Chamber

    CERN Document Server

    Vidal-Sitjes, G

    2003-01-01

    A novel apparatus for the calibration of the HARP Time Projection Chamber has been designed, developed and built. The apparatus consists of a large number of point-like photo-electron sources located at precise positions inside the detector volume. The photo-electron sources are optical quartz fibers on which one end is coated with an aluminum layer of $\\sim$80{\\AA} thickness and are held in place on the High Voltage membrane. The fibers are used to guide UV laser light pulses that generate photoelectrons on the fiber tips and these act as photo-electron emitters. The photoelectrons drift inside the detector and produce the calibration signals. The technique allows to asses $E\\times B$ distortions and to measure drift velocity, ion feedback and time stability in real time. The analog signals generated by the TPC front-end electronics have been characterized. Different methods to extract the amplitude and time of occurrence from the digitized signals have been studied and compared. Fast estimators, like the su...

  9. Urban atmospheres.

    Science.gov (United States)

    Gandy, Matthew

    2017-07-01

    What is an urban atmosphere? How can we differentiate an 'atmosphere' from other facets of urban consciousness and experience? This essay explores some of the wider cultural, political, and philosophical connotations of atmospheres as a focal point for critical reflections on space and subjectivity. The idea of an 'affective atmosphere' as a distinctive kind of mood or shared corporeal phenomenon is considered in relation to recent developments in phenomenology, extended conceptions of agency, and new understandings of materialism. The essay draws in particular on the changing characteristics of air and light to reflect on different forms of sensory experience and their wider cultural and political connotations. The argument highlights some of the tensions and anomalies that permeate contemporary understandings of urban atmospheres.

  10. Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern

    Science.gov (United States)

    Kassotis, Christopher D.; Alvarez, David A.; Taylor, Julia A.; vom Saal, Frederick S.; Nagel, Susan C.; Tillitt, Donald E.

    2015-01-01

    Surface water contamination by chemical pollutants increasingly threatens water quality around the world. Among the many contaminants found in surface water, there is growing concern regarding endocrine disrupting chemicals, based on their ability to interfere with some aspect of hormone action in exposed organisms, including humans. This study assessed water quality at several sites across Missouri (near wastewater treatment plants and airborne release sites of bisphenol A) based on hormone receptor activation potencies and chemical concentrationspresent in the surface water. We hypothesized that bisphenol A and ethinylestradiol would be greater in water near permitted airborne release sites and wastewater treatment plant inputs, respectively, and that these two compounds would be responsible for the majority of activities in receptor-based assays conducted with water collected near these sites. Concentrations of bisphenol A and ethinylestradiol were compared to observed receptor activities using authentic standards to assess contribution to total activities, and quantitation of a comprehensive set of wastewater compounds was performed to better characterize each site. Bisphenol A concentrations were found to be elevated in surface water near permitted airborne release sites, raising questions that airborne releases of BPA may influence nearby surface water contamination and may represent a previously underestimated source to the environment and potential for human exposure. Estrogen and androgen receptor activities of surface water samples were predictive of wastewater input, although the lower sensitivity of the ethinylestradiol ELISA relative to the very high sensitivity of the bioassay approaches did not allow a direct comparison. Wastewater-influenced sites also had elevated anti-estrogenic and anti-androgenic equivalence, while sites without wastewater discharges exhibited no antagonist activities.

  11. Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern.

    Science.gov (United States)

    Kassotis, Christopher D; Alvarez, David A; Taylor, Julia A; vom Saal, Frederick S; Nagel, Susan C; Tillitt, Donald E

    2015-08-15

    Surface water contamination by chemical pollutants increasingly threatens water quality around the world. Among the many contaminants found in surface water, there is growing concern regarding endocrine disrupting chemicals, based on their ability to interfere with some aspect of hormone action in exposed organisms, including humans. This study assessed water quality at several sites across Missouri (near wastewater treatment plants and airborne release sites of bisphenol A) based on hormone receptor activation potencies and chemical concentrations present in the surface water. We hypothesized that bisphenol A and ethinylestradiol would be greater in water near permitted airborne release sites and wastewater treatment plant inputs, respectively, and that these two compounds would be responsible for the majority of activities in receptor-based assays conducted with water collected near these sites. Concentrations of bisphenol A and ethinylestradiol were compared to observed receptor activities using authentic standards to assess contribution to total activities, and quantitation of a comprehensive set of wastewater compounds was performed to better characterize each site. Bisphenol A concentrations were found to be elevated in surface water near permitted airborne release sites, raising questions that airborne releases of BPA may influence nearby surface water contamination and may represent a previously underestimated source to the environment and potential for human exposure. Estrogen and androgen receptor activities of surface water samples were predictive of wastewater input, although the lower sensitivity of the ethinylestradiol ELISA relative to the very high sensitivity of the bioassay approaches did not allow a direct comparison. Wastewater-influenced sites also had elevated anti-estrogenic and anti-androgenic equivalence, while sites without wastewater discharges exhibited no antagonist activities. Published by Elsevier B.V.

  12. Atmospheric pollution; Pollution atmospherique

    Energy Technology Data Exchange (ETDEWEB)

    Lambrozo, J.; Guillossou, G. [EDF-Gas de France, Service des Etudes Medicales, 75 - Paris (France)

    2008-10-15

    The atmosphere is the reservoir of numerous pollutants (nitrogen oxides, sulfur oxides, carbon oxides, particulates, volatile organic compounds, polycyclic aromatic hydrocarbons) from natural origin or anthropogenic origin ( industry, transport, agriculture, district heating). With epidemiologic studies the atmospheric pollution is associated with an increase of respiratory and cardiovascular diseases. At the european level, the technological progress, the legislation have allowed a reduction of pollutant emissions, however these efforts have to be continued because the sanitary impact of atmospheric pollution must not be underestimated, even if the risks appear less important that these ones in relation with tobacco, inside pollution or others factors of cardiovascular risks. Indeed, on these last factors an individual action is possible for the exposure to air pollution people have no control. (N.C.)

  13. Organic Aerosol Nucleation and Growth at the CERN CLOUD chamber

    Science.gov (United States)

    Tröstl, Jasmin; Lethipalo, Katrianne; Bianchi, Federico; Sipilä, Mikko; Nieminen, Tuomo; Wagner, Robert; Frege, Carla; Simon, Mario; Weingartner, Ernest; Gysel, Martin; Dommen, Josef; Baltensperger, Urs

    2014-05-01

    It is well known that atmospheric aerosols influence the climate by changing Earth's radiation balance (IPCC 2007 and 2013). Recent models have shown (Merikanto et al. 2009) that aerosol nucleation is one of the biggest sources of low level cloud condensation nuclei. Still, aerosol nucleation and growth are not fully understood. The driving force of nucleation and growth is sulfuric acid. However ambient nucleation and growth rates cannot be explained by solely sulfuric acid as precursor. Recent studies have shown that only traces of precursors like ammonia and dimethylamine enhance the nucleation rates dramatically (Kirkby et al. 2011, Almeida et al., 2013). Thus the role of different aerosol precursor needs to be studied not only in ambient but also in very well controlled chamber experiments. The CLOUD (Cosmics Leaving OUtdoor Droplets) experiment enables conducting experiments very close to atmospheric conditions and with a very low contaminant background. The latest CLOUD experiments focus on the role of organics in aerosol nucleation and growth. For this purpose, numerous experiments with alpha-pinene have been conducted at the CERN CLOUD chamber. Several state-of-the-art instruments were used to cover the whole complexity of the experiment. Chamber conditions were set to 40% relative humidity and 5° C. Atmospheric concentrations of SO2, O3, HONO, H2O and alpha-pinene were injected to the chamber. Different oxidation conditions were used, yielding different levels of oxidized organics: (1) OH radicals, (2) Ozone with the OH scavenger H2 (pure ozonolysis) and (3) both. SO2 was injected to allow for sulfuric acid production. Optical UV fibers were used to enable photochemical reactions. A high field cage (30 kV) can be turned on to remove all charged particles in the chamber to enable completely neutral conditions. Comparing neutral conditions to the beam conditions using CERN's proton synchrotron, the fraction of ion-induced nucleation can be studied. Using

  14. Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

    Science.gov (United States)

    Penry, J F; Upton, J; Mein, G A; Rasmussen, M D; Ohnstad, I; Thompson, P D; Reinemann, D J

    2017-01-01

    The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece

  15. Atmospheric Concentrations, Gas/Particle Partitioning And Exposure Risk Of Polycyclic Aromatic Hydrocarbons (PAHs) At Background, Rural Village And Urban Sites In The North China Plain

    Science.gov (United States)

    Wang, W.; Simonich, S.; Zhao, J.; Xue, M.; Wang, W.; Tao, S.

    2009-05-01

    from the model predictions. Finally, the human exposure risk was assessed using the PAH toxic equivalent concentrations based on benzo(a)pyrene (TEQBaP). The annual average TEQBaP in Donghe was 18.6±20.1 ng/ m3, which was 1.8 times higher than the Chinese national standard of 10 ng/ m3 and 18.6 times higher than the WHO guideline of 1 ng/ m3, and 53.8, 2.3, 2.0 times higher than Xiaolongmen, Gubeikou and Beijing, respectively. In Donghe, coal and biofuel combustion are still the major energy sources and the combustion of these fuels in low-efficiency family stoves, and other combustion facilities, was the major reason for the high PAH levels.

  16. Atmospheric Infancy

    DEFF Research Database (Denmark)

    Roald, Tone; Pedersen, Ida Egmose; Levin, Kasper

    2017-01-01

    In this article we establish intersubjective meaning-making in infancy as atmospheric. Through qualitative descriptions of five mother–infant dyads in a video-recorded, experimental setting when the infant is 4, 7, 10, and 13 months, we discovered atmospheric appearances with a developmental...... pattern of atmospheric variations. These appearances, we argue, are contextual and intersubjective monologues. The monologues are similar to what Daniel Stern describes with his concept of “vitality affects,” but they arise as a unified force that envelops the mother and child. As such, we present a new...

  17. Monitored Drift Chambers in the ATLAS Detector

    CERN Document Server

    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...

  18. Characteristics of laryngeal symptoms induced in patients with allergic rhinitis in an environmental challenge chamber.

    Science.gov (United States)

    Suzuki, Takeshi; Okamoto, Yoshitaka; Yonekura, Syuji; Okuma, Yusuke; Sakurai, Toshioki; Sakurai, Daiju

    2016-06-01

    People with allergic rhinitis often have laryngeal symptoms (LSs) in addition to nasal symptoms during the pollen-scattering season. To clarify the characteristics of the LSs induced by pollen exposure using an environmental challenge chamber. Cypress pollen exposure using an environmental challenge chamber for 25 participants with cypress pollen-induced allergic rhinitis was performed for 3 hours for 2 consecutive days in 3 study courses: namely, pollen exposure under normal nasal breathing and pollen or sham pollen exposure with nasal blockage, which eliminated any allergic reactions in the nasal mucosa. The nasal and LSs scores and the levels of serum inflammatory mediators, including eosinophil cationic protein (ECP), were monitored. Laryngeal examinations and physiologic lung tests were also conducted. Various LSs were reported, and these LSs were significantly elevated during pollen exposure and even under sham exposure with artificial nasal blockage. The pollen exposure with artificial nasal blockage exaggerated the LSs in 32% of the participants and also increased the serum ECP levels. The serum ECP levels did not change after sham exposure. The findings of both laryngeal examinations and lung tests failed to reveal any significant changes. Nasal obstruction could induce significant LSs even without pollen exposure. LSs were enhanced by pollen exposure and allergic reactions in the larynx could thus be involved in this enhancement. clinicaltrials.gov Identifier: UMIN000015667. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  19. Flow Characteristics of Multi-circular Jet Plate in Premix Chamber of Air-Assist Atomizer for Burner System

    Directory of Open Access Journals (Sweden)

    Amirnordin Shahrin Hisham

    2016-01-01

    Full Text Available The flow characteristics of multi-circular jet (MCJ plate in the premix chamber of an atomizer were investigated using Computational Fluid Dynamics. Multiphase volume of fluid behavior inside the chamber was determined via steady simulations. The Eulerian–Eulerian two-fluid approach was used for execution mixing of diesel fuel and air. Spray simulation using the discrete phase with injection was generated from the nozzle hole into the ambient atmosphere. The behavior of three MCJ plates in the premix chamber was studied numerically. Results illustrated that plate open area, Ae, influenced the turbulence inside the chamber. MCJ 3, which had the lowest open area, generated the highest flow velocity and turbulence kinetic energy compared with MCJ 1 and 2. The MCJ plates could increase the turbulence in the premix chamber and contribute to the combustion efficiency.

  20. Mimicking Mars: A vacuum simulation chamber for testing environmental instrumentation for Mars exploration

    Energy Technology Data Exchange (ETDEWEB)

    Sobrado, J. M., E-mail: sobradovj@inta.es; Martín-Soler, J. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Martín-Gago, J. A. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Instituto de Ciencias de Materiales de Madrid (ICMM-CSIC), Cantoblanco, 28049 Madrid (Spain)

    2014-03-15

    We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10{sup −6} mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

  1. Mimicking Mars: a vacuum simulation chamber for testing environmental instrumentation for Mars exploration.

    Science.gov (United States)

    Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

    2014-03-01

    We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10(-6) mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

  2. Flow Characteristics of Multi-circular Jet Plate in Premix Chamber of Air-Assist Atomizer for Burner System

    OpenAIRE

    Amirnordin Shahrin Hisham; Khalid Amir; Ismail Isma Adzrai; Yii Shi Chin Ronny; Fawzi Mas

    2016-01-01

    The flow characteristics of multi-circular jet (MCJ) plate in the premix chamber of an atomizer were investigated using Computational Fluid Dynamics. Multiphase volume of fluid behavior inside the chamber was determined via steady simulations. The Eulerian–Eulerian two-fluid approach was used for execution mixing of diesel fuel and air. Spray simulation using the discrete phase with injection was generated from the nozzle hole into the ambient atmosphere. The behavior of three MCJ plates in t...

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. A new microcirculation chamber for inexpensive long-term investigations of nervous tissue in vitro.

    Science.gov (United States)

    Thiemann, W; Malisch, R; Reymann, K G

    1986-07-01

    The construction of a simple universal chamber for long-term recording from submerged and interface brain slices is described. The medium is circulated and oxygenated constantly by an O2-CO2 gas mixture using the principle of a bubble pump. The design permits experiments which require long-term exposure to expensive drugs as well as great economy of oxygen consumption.

  8. Reflectivity level of radio anechoic chambers

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1973-01-01

    A comparison between the antenna-pattern comparison technique and the free-space voltage standing-wave ratio technique for evaluating the reflectivity level of radio anechoic chambers is presented. Based on an analysis of the two techniques, it is pointed out which parameters influence the measured...... be used to measure the improvements. This work is inspired by the current discussion of finding a figure of merit for anechoic chambers. Based on the results, an evaluation procedure for anechoic chambers is indicated. However, it is pointed out and illustrated by examples that further investigations...... value of the reflectivity level. The comparison is illustrated with experimental results and it is explained why inconsistent and uncorrelated results may be found when the two methods are used. Furthermore, it is demonstrated, by introducing improvements in a chamber, how the reflectivity level can...

  9. 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...

  10. Developing cloud chambers with high school students

    CERN Document Server

    Ishizuka, Ryo; Sato, Shoma; Zeze, Syoji

    2013-01-01

    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 detail of the chamber is presented. We also argue how the project affects student's cognition, motivation, academic skills and behavior. The research project had been done in very similar way to those of professional researchers, i.e., planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we learn that such style of scientific activity is very effective in promoting student's motivation for learning science.

  11. High Performance Methane Thrust Chamber (HPMTC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a High-Performance Methane Thrust Chamber (HPMRE) to meet the demands of advanced chemical propulsion systems for deep-space mission...

  12. 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....

  13. 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...

  14. 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.

  15. New measurement methods for anechoic chamber characterization

    OpenAIRE

    Gómez Alfageme, Juan José; Sanchez Bote, José Luis; Blanco Martín, Elena

    2008-01-01

    As a continuation of the work presented in 122nd AES Convention, this paper tries to study in depth the anechoic chambers qualification. The purpose of this paper is to find parameters that allow the characterization of this type of enclosures. The proposal that becomes in this work is trying to obtain data of the anechoic chambers absorption by means of the transfer functions between pairs of microphones, or by means of the impulse response between pairs of microphones. Based on the results ...

  16. Signal shapes in a TPC wire chamber

    Science.gov (United States)

    Rossegger, S.; Riegler, W.

    2010-11-01

    We study signal shapes in Multi Wire Proportional Chambers (MWPCs) and the influence of the electron distribution around the wire on the ion tail characteristics. Simulations of the ion tail for two different geometries, different voltages and therefore gas gains were performed. These simulations are compared to measurements carried out with the ALICE TPC wire chambers for a Ne/CO 2/N 2 gas mixture, which allows to extract the avalanche spread around the anode wires of the MWPC.

  17. 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.

  18. The Gargamelle heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    This image shows the Gargamelle heavy liquid bubble chamber. It was used to detect particles in experiments at the PS between 1970 and 1976 before being moved to the SPS. In 1973, while working on the PS, it detected the first neutral current, an interaction vital to the electroweak theory. In 1978 a large fissure appeared in the body of the chamber and Gargamelle was stopped in 1979.

  19. The world's largest time projection chamber

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Peter Glassel, the technical coordinator for the ALICE time projection chamber, is seen sitting inside the detector; the largest in the world at nearly 100 cubic metres. Thousands of wires are connected to read out electronic data produced as particles are created in lead-lead collisions at the centre of the detector. These particles will cause the medium within the time projection chamber to ionise along their tracks allowing the particle paths to be recreated.

  20. Atmospheric neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kajita, Takaaki [Research Center for Cosmic Neutrinos, Institute for Cosmic Ray Research, University of Tokyo, Kashiwa-no-ha 5-1-5, Kashiwa, Chiba 277-8582 (Japan)

    2004-12-01

    Neutrino oscillation was discovered through the study of atmospheric neutrinos. Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron neutrinos and muon neutrinos are produced mainly by the decay chain of charged pions to muons and electrons. Depending on the energy of the neutrinos, atmospheric neutrinos are observed as fully contained events, partially contained events and upward-going muon events. The energy range covered by these events is from a few hundred MeV to >1 TeV. Data from various experiments showed zenith angle- and energy-dependent deficit of {nu}{sub {mu}} events, while {nu}{sub e} events did not show any such effect. It was also shown that the {nu}{sub {mu}} survival probability obeys the sinusoidal function as predicted by neutrino oscillations. Two-flavour {nu}{sub {mu}} {r_reversible} {nu}{sub {tau}} oscillations, with sin{sup 2} 2{theta} > 0.90 and {delta}m{sup 2} in the region of 1.9 x 10{sup -3} to 3.0 x 10{sup -3} eV{sup 2}, explain all these data. Various detailed studies using high statistics atmospheric neutrino data excluded the alternative hypotheses that were proposed to explain the {nu}{sub {mu}} deficit.

  1. Laser peripheral iridotomy changes anterior chamber architecture.

    Science.gov (United States)

    Theinert, Christian; Wiedemann, Peter; Unterlauft, Jan D

    2017-01-19

    The pressure gradient between anterior and posterior chamber in acute angle closure (AAC) and primary angle closure suspects is balanced by a sufficient laser peripheral iridotomy (LPI). The anterior chamber changes induced by LPI in patients with unilateral AAC were examined and compared to healthy eyes to define threshold values, which may help to discriminate between healthy and diseased eyes. Using Scheimpflug photography, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and central corneal thickness (CCT) were measured before and after LPI in both eyes of unilateral AAC cases. These measurements were compared to a group of healthy control eyes to determine threshold values for ACD, ACV, and ACA. The ACD, ACV, and ACA increased significantly in the 25 AAC eyes after LPI. The ACD, ACV, ACA, and CCT values in the AAC eyes obtained before LPI were compared to a control group of 59 healthy eyes with wide open chamber angles. The cutoff values revealed by receiver operating characteristic analysis were 2.1 mm for ACD, 90.5 mm2 for ACV, and 27.25° for ACA. Our results confirm the significant changes of the anterior segments architecture induced by LPI in AAC eyes. The found threshold values for ACD, ACV, and ACA may help in daily clinical routine to discriminate between healthy eyes and those in need for a prophylactic LPI.

  2. In vitro penetration of bleaching agents into the pulp chamber

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Valera, M C; Mancini, M N G

    2004-01-01

    To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures.......To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures....

  3. Study of atmospheric tritium transfers in lettuce: kinetic study, equilibrium and organic incorporation during a continuous atmospheric exposure; Etude des transferts du tritium atmospherique chez la laitue: Etude cinetique, etat d'equilibre et integration du tritum sous forme organique lors d'une exposition atmospherique continue

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, C.

    2009-11-30

    This thesis has explored the mechanisms of tritium 'absorption and incorporation in a human-consumed plant, lettuce (Lactuca sativa L.), due to atmospheric exposure. Foliar uptake appears to play a key role in absorption of tritium as tissue free water tritium. Whatever the development stage and the light conditions, the specific activity in tissue free water reaches that of water vapour in air in several hours. The specific activity ratio is then about 0, 4. The time to reach equilibrium in soil is over 24 hours in most cases: the specific activity ratio ranges then 0, 01 to 0, 26. Incorporation rate of tissue free water tritium as organically-bound tritium has been estimated to 0, 13 to 0, 16 % h-l in average over the growing period of the plant, but marked variations are observed during growth. In particular, a significant increase appeared at the exponential growth stage. Deposition and diffusion of tritium in soil lead to significant OBT activities in soil. Results globally indicate equilibrium between the different environmental compartments (air, soil, plant). However, some experiments have revealed high OBT concentrations regarding atmospheric level exposure and ask for a possible phenomenon of local tritium accumulation in OBT for particular conditions of exposure. (author) [French] Ce travail de these a concerne l'etude des phenomenes d'absorption et d'incorporation sous forme organique du tritium dans un vegetal de consommation courante, la laitue (Lactuca sativa L.), en reponse a une exposition atmospherique. Il apparait que la voie foliaire joue un role primordial dans l'absorption du tritium au sein de l'eau tissulaire des plants. Quels que soient le stade de developpement des plants et les conditions d'eclairement, le temps necessaire pour atteindre l'equilibre des concentrations dans l'eau libre et dans la vapeur d'eau de l'air est de plusieurs heures; le rapport des concentrations est alors de

  4. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  5. Development and evaluation of an instantaneous atmospheric corrosion rate monitor

    Science.gov (United States)

    Mansfeld, F.; Jeanjaquet, S. L.; Kendig, M. W.; Roe, D. K.

    1985-06-01

    A research program was carried out in which a new instantaneous atmospheric corrosion rate monitor (ACRM) was developed and evaluated, and equipment was constructed which will allow the use of many sensors in an economical way in outdoor exposures. In the first task, the ACRM was developed and tested in flow chambers in which relative humidity and gaseous and particulate pollutant levels can be controlled. Diurnal cycles and periods of rain were simulated. The effects of aerosols were studied. A computerized system was used for collection, storage, and analysis of the electrochemical data. In the second task, a relatively inexpensive electronics system for control of the ACRM and measurement of atmospheric corrosion rates was designed and built. In the third task, calibration of deterioration rates of various metallic and nonmetallic materials with the response of the ACRMs attached to these materials was carried out under controlled environmental conditions using the system developed in the second task. A Quality Assurance project plan was prepared with inputs from the Rockwell International Environmental Monitoring and Service Center and Quality Assurance System audits were performed.

  6. Quantificação de fluxos de mercúrio gasoso na interface solo/atmosfera utilizando câmara de fluxo dinâmica: aplicação na bacia do Rio Negro Quantification of atmosphere - soil mercury fluxes by using a dynamic flux chamber: application at the Negro River basin, Amazon

    Directory of Open Access Journals (Sweden)

    Gabriella Magarelli

    2005-12-01

    Full Text Available Gaseous mercury sampling conditions were optimized and a dynamic flux chamber was used to measure the air/surface exchange of mercury in some areas of the Negro river basin with different vegetal coverings. At the two forest sites (flooding and non-flooding, low mercury fluxes were observed: maximum of 3 pmol m-2 h-1 - day and minimum of -1 pmol m-2 h-1 - night. At the deforested site, the mercury fluxes were higher and always positive: maximum of 26 pmol m-2 h-1 - day and 17 pmol m-2 h-1 - night. Our results showed that deforestation could be responsible for significantly increasing soil Hg emissions, mainly because of the high soil temperatures reached at deforested sites.

  7. Cloud droplet activity changes of soot aerosol upon smog chamber ageing

    Science.gov (United States)

    Wittbom, C.; Eriksson, A. C.; Rissler, J.; Carlsson, J. E.; Roldin, P.; Nordin, E. Z.; Nilsson, P. T.; Swietlicki, E.; Pagels, J. H.; Svenningsson, B.

    2014-09-01

    Particles containing soot, or black carbon, are generally considered to contribute to global warming. However, large uncertainties remain in the net climate forcing resulting from anthropogenic emissions of black carbon (BC), to a large extent due to the fact that BC is co-emitted with gases and primary particles, both organic and inorganic, and subject to atmospheric ageing processes. In this study, diesel exhaust particles and particles from a flame soot generator spiked with light aromatic secondary organic aerosol (SOA) precursors were processed by UV radiation in a 6 m3 Teflon chamber in the presence of NOx. The time-dependent changes of the soot nanoparticle properties were characterised using a Cloud Condensation Nuclei Counter, an Aerosol Particle Mass Analyzer and a Soot Particle Aerosol Mass Spectrometer. The results show that freshly emitted soot particles do not activate into cloud droplets at supersaturations ≤2%, i.e. the BC core coated with primary organic aerosol (POA) from the exhaust is limited in hygroscopicity. Before the onset of UV radiation it is unlikely that any substantial SOA formation is taking place. An immediate change in cloud-activation properties occurs at the onset of UV exposure. This change in hygroscopicity is likely attributed to SOA formed from intermediate volatility organic compounds (IVOCs) in the diesel engine exhaust. The change of cloud condensation nuclei (CCN) properties at the onset of UV radiation implies that the lifetime of soot particles in the atmosphere is affected by the access to sunlight, which differs between latitudes. The ageing of soot particles progressively enhances their ability to act as cloud condensation nuclei, due to changes in: (I) organic fraction of the particle, (II) chemical properties of this fraction (e.g. primary or secondary organic aerosol), (III) particle size, and (IV) particle morphology. Applying κ-Köhler theory, using a κSOA value of 0.13 (derived from independent input

  8. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    Nurses working in the Neuro-Intensive Care Unit at Aarhus University Hospital lack the tools to prepare children for the alarming atmosphere they will enter when visiting a hospitalised relative. The complex soundscape dominated by alarms and sounds from equipment is mentioned as the main stressor...

  9. Atmospheric humidity

    Science.gov (United States)

    Water vapor plays a critical role in earth's atmosphere. It helps to maintain a habitable surface temperature through absorption of outgoing longwave radiation, and it transfers trmendous amounts of energy from the tropics toward the poles by absorbing latent heat during evaporation and subsequently...

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

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

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

  11. Repair of isolated double-chambered right ventricle | El Kouache ...

    African Journals Online (AJOL)

    The finding of a double-chambered right ventricle (DCRV) is exceptionally rare as an isolated anomaly. It is a congenital cardiac anomaly in which the right ventricle is separated into two chambers, a proximal highpressure chamber and a distal low-pressure chamber, by anomalous muscles or fibrous tissues in the right ...

  12. Change of Pressing Chamber Conicalness at Briquetting Process in Briquetting Machine Pressing Chamber

    Directory of Open Access Journals (Sweden)

    Peter Križan

    2012-01-01

    Full Text Available In this paper, we will present the impact of the conical shape of a pressing chamber, an important structural parameter. Besides the known impact of the technological parameters of pressing chambers, it is also very important to pay attention to their structural parameters. In the introduction, we present a theoretical analysis of pressing chamber conicalness. An experiment aimed at detecting this impact was performed at our institute, and it showed that increasing the conicalness of a pressing chamber improves the quality of the final briquettes. The conicalness of the pressing chamber has a significanteffect on the final briquette quality and on the construction of briquetting machines. The experimental findings presented here show the importance of this parameter in the briquetting process.

  13. Changes of body fluid and hematology in toad and their rehabilitation following intermittent exposure to simulated high altitude

    Science.gov (United States)

    Biswas, H. M.; Boral, M. C.

    1986-06-01

    Three groups of adult male toads were exposed intermittently in a decompression chamber for a daily period of 4 and 8 hours at a time for 6 consecutive days to an “altitude” of 12,000; 18,000 and 24,000 feet (3658; 5486; 7315 m) respectively. Most of the exposed animals were sacrificed immediately after the last exposure, but only a few animals experiencing 8 hours of exposure were sacrificed after a further 16 hours of exposure at normal atmospheric pressure. Eight hours of daily exposure for 6 days causes a decrease of body fluids and an increase of hematological parameters in all the altitude exposed animals compared with to the changes noted in the animals having 4 hours of daily exposure for 6 days at the same altitude levels. The animals that were exposed to pressures equivalent to altitudes of 12,000 and 18,000 feet daily for 8 hours were found to return nearly to their normal body fluids and hematological balance after 16 hours of exposure to normal atmospheric pressure, whereas the animals exposed for a similar period at an equivalent 24,000 feet failed to get back their normal balance of body fluids and hematology after 16 hours of exposure at normal atmospheric pressure. The present experiment shows that the body weight loss and changes of body fluid and hematological parameters in the toad after exposure to simulated high altitude are due not only to dehydration, but suggest that hypoxia may also have a role.

  14. Commissioning of SLAC SLD 45-Degree Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Eschenburg, Vance O.

    2002-07-19

    The SLD experiment at the Stanford Linear Accelerator Center had a significant gap in its muon tracking coverage, provided by the Warm Iron Calorimeter. Supplemental planes of limited streamer tube chambers were added to improve the coverage in the vicinity of the gap at 0.65 < |cos{theta}| < 0.85. A software effort to upgrade the tracking software for this system is detailed. The commissioning of the forty-five degree chamber region of the SLAC SLD Warm Iron Calorimeter is presented. This task involved the completion of the forty-five degree chamber region geometry for the Warm Iron Calorimeter's fitter and swimmer and the changing of the way multiple scattering effects are treated in the fitter algorithm.

  15. Rapid-Cycling Bubble-Chamber, details

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    Parts of the hydraulic expansion system of the Rapid-Cycling Bubble-Chamber (RCBC). RCBC was the largest of 3 rapid-cycling bubble-chambers (the others were LEBC and HOLEBC), used as target- and vertex-detectors within the European Hybrid Spectrometer (EHS) in the SPS North Area (EHN1). RCBC contained 250 l of liquid hydrogen and was located inside a 3 T superconducting magnet. It was designed for 30 expansions/s (100 times faster than BEBC), the system shown here allowed 50 expansions/s. RCBC operated from 1981 to 1983 for experiments NA21, NA22 and NA23 at a rate of 15 expansions/s, clocking up a total of over 4 million. In the rear, at left, is bearded Lucien Veillet; Augustin Didona is at the right. See also 8001009. The installation of the piston assembly in the RCBC chamber body is shown in the Annual Report 1980, p.65.

  16. Thermal Vacuum Chamber Repressurization with Instrument Purging

    Science.gov (United States)

    Woronowicz, Michael

    2017-01-01

    At the end of James Webb Space Telescope (JWST) OTIS (Optical Telescope Element-OTE-Integrated Science Instrument Module-ISIM) cryogenic vacuum testing in NASA Johnson Space Centers (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are mooting the idea that chamber particulate material stirred up by the repressurization process may be kept from falling into the ISIM interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This memo describes development of a series of models designed to describe this process. These are strung together in tandem to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

  17. High temperature thrust chamber for spacecraft

    Science.gov (United States)

    Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

    1998-01-01

    A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

  18. Anterior chamber collapse syndrome in a koala.

    Science.gov (United States)

    Liddle, Vl; Naranjo, C; Bernays, Me

    2014-05-01

    Anterior chamber collapse syndrome has been recognised in various species and is associated with early-life ocular disease or trauma. It is important to differentiate this acquired condition from a congenital malformation. An adult female koala (Phascolarctos cinereus) was referred for assessment of buphthalmos and severe keratitis of the right eye. The degree of keratitis obstructed examination of intraocular structures. Enucleation of the affected eye was performed and the histopathological diagnosis was anterior chamber collapse syndrome and secondary glaucoma. This case contributes to the limited information available in the literature on anterior chamber collapse syndrome, a disease unique in having secondary glaucoma with minimal or no inflammation. The case also expands the literature available on ocular disease in koalas. More specifically, this is the only reported case of glaucoma, of any aetiology, in the koala. © 2014 Australian Veterinary Association.

  19. Emulsion chamber experiments for the Space Station

    Science.gov (United States)

    Wilkes, R. J.

    Emulsion chambers offer several unique features for the study of ultrahigh-energy cosmic-ray interactions and spectra aboard a permanent manned Space Station. Emulsion-chamber experiments provide the highest acceptance/weight ratio of any current experimental technique, are invulnerable to mechanical shocks and temperature excursions associated with space flight, do not employ volatile or explosive components or materials, and are not dependent upon data communications or recording systems. Space-Station personnel would be employed to replace track-sensitive materials as required by background accumulation. Several emulsion-chamber designs are proposed, including both conventional passive calorimetric detectors and a hybrid superconducting-magnetic-spectrometer system. Results of preliminary simulation studies are presented. Operational logistics are discussed.

  20. Experimental and Numerical Research of a Novel Combustion Chamber for Small Gas Turbine Engines

    Directory of Open Access Journals (Sweden)

    Hybl R.

    2013-04-01

    Full Text Available New combustion chamber concept (based on burner JETIS-JET Induced Swirl for small gas turbine engine (up to 200kW is presented in this article. The combustion chamber concept is based on the flame stabilization by the generated swirl swirl generated by two opposite tangentially arranged jet tubes in the intermediate zone, this arrangement replaces air swirler, which is very complicated and expensive part in the scope of small gas turbines with annular combustion chamber. The mixing primary jets are oriented partially opposite to the main exhaust gasses flow, this enhances hot product recirculation and fuel-air mixing necessary for low NOx production and flame stability. To evaluate the designed concept a JETIS burner demonstrator (methane fuel was manufactured and atmospheric experimental measurements of CO, NOx for various fuel nozzles and jet tubes the configuration were done. Results of these experiments and comparison with CFD simulation are presented here. Practical application of the new chamber concept in small gas turbine liquid fuel combustor was evaluated (verified on 3 nozzles planar combustor sector test rig at atmospheric conditions results of the experiment and numerical simulation are also presented.

  1. Atmospheric materiality

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2016-01-01

    A disjunction between the material and the immaterial has been at the heart of the architectural debate for decades. In this dialectic tension, the notion of atmosphere which increasingly claims attention in architectural discourse seems to be parallactic, leading to the re-evaluation of perceptual...... experience and, consequently, to the conceptual and methodological shifts in the production of space, and hence in the way we think about materiality. In this context, architectural space is understood as a contingent construction – a space of engagement that appears to us as a result of continuous...... and complex interferences revealed through our perception; ‘the atmospheric’ is explored as a spatial and affective quality as well as a sensory background, and materiality as a powerful and almost magical agency in shaping of atmosphere. Challenging existing dichotomies and unraveling intrinsic...

  2. Sensory and other neurogenic effects of exposures to airborne office dust

    Science.gov (United States)

    Mølhave, L.; Kjærgaard, S. K.; Attermann, J.

    This Danish Office Dust Experiment investigated the response of 24 healthy non-sensitive adult subjects to exposure to normal office dust in the air (7 μg m -3 clean air, 136 and 390 μg m -3 TSP). The dust had no major identifiable specific reactive components. The exposure duration was 5 1/4 h and was arranged in a climate chamber in controlled atmospheric conditions. Measurements were made acutely at exposure onset, subacutely at exposure end and next day (late). As secondary aims the time course and threshold of any observed effect of the exposures, and the characteristics of any hyperresponding subgroup were investigated. In a questionnaire with 36 questions the dust exposures caused increased acute, subacute and late perceptions of reduced air quality, acute and subacute increased odor intensity, acute eye irritation, acute and late heavy head, subacute feeling of perspiration, and subacute general irritation. Cough increased subacutely during exposures. In addition, a performance test showed effects of dust exposures which also affected "Mood Scale" ratings. No effect was seen on an addition test for distraction, and objective measurements of skin humidity. The overall conclusion of the study is that healthy subjects without hypersensitivity reactions seem to respond to airborne house dust. The responses are both subjective sensory reactions and other neurogenic effects even at exposure levels within the range found in normal buildings. Some of the effects appeared acutely and decreased through adaptation while others increased during prolonged exposure and remained for more than 17 h after the exposure ended. The findings may indicate for this type of dust a threshold level for the dose-response relationships below 140 μg m -3.

  3. Low Temperature Atmospheric Pressure Plasma Sterilization Shower

    Science.gov (United States)

    Gandhiraman, R. P.; Beeler, D.; Meyyappan, M.; Khare, B. N.

    2012-10-01

    Low-temperature atmospheric pressure plasma sterilization shower to address both forward and backward biological contamination issues is presented. The molecular effects of plasma exposure required to sterilize microorganisms is also analysed.

  4. Exploring the boundary between a siphon and barometer in a hypobaric chamber.

    Science.gov (United States)

    Hughes, Stephen; Gurung, Som

    2014-04-22

    Siphons have been used since ancient times, but exactly how they work is still a matter of debate. In order to elucidate the modus operandi of a siphon, a 1.5 m high siphon was set up in a hypobaric chamber to explore siphon behaviour in a low-pressure environment. When the pressure in the chamber was reduced to about 0.18 atmospheres, a curious waterfall-like feature appeared downstream from the apex of the siphon. A hypothesis is presented to explain the waterfall phenomenon. When the pressure was reduced further the siphon broke into two columns--in effect becoming two back-to-back barometers. This experiment demonstrates the role of atmospheric pressure in explaining the hydrostatic characteristics of a siphon and the role of molecular cohesion in explaining the hydrodynamic aspects.

  5. A Monte Carlo study of radon detection in cylindrical diffusion chambers

    Energy Technology Data Exchange (ETDEWEB)

    Rickards, Jorge, E-mail: rickards@fisica.unam.m [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito de la Investigacion Cientifica, Ciudad Universitaria, Delegacion Coyoacan, 04520 Mexico, D.F. (Mexico); Golzarri, Jose-Ignacio, E-mail: golzarri@fisica.unam.m [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito de la Investigacion Cientifica, Ciudad Universitaria, Delegacion Coyoacan, 04520 Mexico, D.F. (Mexico); Espinosa, Guillermo, E-mail: espinosa@fisica.unam.m [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito de la Investigacion Cientifica, Ciudad Universitaria, Delegacion Coyoacan, 04520 Mexico, D.F. (Mexico)

    2010-05-15

    The functioning of radon diffusion chambers was studied using the Monte Carlo code RAMMX developed here. The alpha particles from radon are assumed randomly produced in the volume of the cylinder, and those from the progeny are assumed to originate randomly at the cylindrical surface. The energy spectrum, the distribution of incident angles, and the distribution of path lengths of the alpha particles on the detector were obtained. These quantities vary depending on input parameters such as initial alpha particle energy, radius and depth of the diffusion chamber, detector size and atmospheric pressure. The calculated energy spectrum for both {sup 222}Rn and {sup 220}Rn was compared with experiment, permitting the identification of each peak and its origin, and a better understanding of radon monitoring. Three aspects not considered in previous calculations are progeny alphas coming from surfaces of the monitor, taking into account the atmospheric pressure, and including the isotope {sup 220}Rn.

  6. Almond Test Body. [for microwave anechoic chambers

    Science.gov (United States)

    Dominek, Allen K. (Inventor); Wood, Richard M. (Inventor); Gilreath, Melvin C. (Inventor)

    1989-01-01

    The invention is an almond shaped test body for use in measuring the performance characteristics of microwave anechoic chambers and for use as a support for components undergoing radar cross-section measurements. The novel aspect of this invention is its shape, which produces a large dynamic scattered field over large angular regions making the almond valuable for verifying the performance of microwave anechoic chambers. As a component mount, the almond exhibits a low return that does not perturb the measurement of the component and it simulates the backscatter characteristics of the component as if over an infinite ground plane.

  7. Sealed Plant-Growth Chamber For Clinostat

    Science.gov (United States)

    Brown, Christopher S.; Dreschel, Thomas W.

    1993-01-01

    Laboratory chamber for growing plants used to measure photosynthesis and respiration in simulated microgravity. Holds plant specimens while rotated on clinostat, see article, "Clinostat Delivers Power To Plant-Growth Cabinets" (KSC-11537). Provides way of comparing gas-exchange rates of plants rotated horizontally on clinostat with those of stationary or vertically rotated plants. Gas extracted for analysis without stopping clinostat. Chamber includes potlike base and cylindrical cover, both made of transparent acrylic pipe. Gasket forms seal between cover and bottom plate of base. Cover bolted to pot baseplate, which in turn bolted to clinostat.

  8. Permeability of MDT chambers to water vapor

    CERN Document Server

    Palestini, S

    2003-01-01

    Tests of MDT chambers performed at the GIF facility and in the H8 test-beam area have shown relative high levels of water vapor contamination in the gas-mixture at the detector output. This effects significantly the drift properties of the MDTs. This note shows that amount of water observed is compatible with approximate estimates based on the permeability of Noryl, used in the tube end-plugs, and of EPDM, used in the O-rings of the on-chamber gas distribution.

  9. A view inside the Gargamelle bubble chamber

    CERN Multimedia

    1970-01-01

    Gargamelle was the name given to a big bubble chamber built at the Saclay Laboratory in France during the late 1960s. It was designed principally for the detection at CERN of the elusive particles called neutrinos. A bubble chamber contains a liquid under pressure, which reveals the tracks of electrically charged particles as trails of tiny bubbles when the pressure is reduced. Neutrinos have no charge, and so leave no tracks, but the aim with Gargamelle was "see neutrinos" by making visible any charged particles set in motion by the interaction of neutrinos in the liquid

  10. Almond test body. [for microwave anechoic chambers

    Science.gov (United States)

    Dominek, Allen K. (Inventor); Wood, Richard M. (Inventor); Gilreath, Melvin C. (Inventor)

    1989-01-01

    The invention is an almond shaped test body for use in measuring the performance characteristics of microwave anechoic chambers and for use as a support for components undergoing radar cross-section measurements. The novel aspect of this invention is its shape, which produces a large dynamic scattered field over large angular regions making the almond valuable for verifying the performance of microwave anechoic chambers. As a component mount, the almond exhibits a low return that does not perturb the measurement of the component and it simulates the backscatter characteristics of the component as if over an infinite ground plane.

  11. Multigas Leakage Correction in Static Environmental Chambers Using Sulfur Hexafluoride and Raman Spectroscopy.

    Science.gov (United States)

    Jochum, Tobias; von Fischer, Joseph C; Trumbore, Susan; Popp, Jürgen; Frosch, Torsten

    2015-11-03

    In static environmental chamber experiments, the precision of gas flux measurements can be significantly improved by a thorough gas leakage correction to avoid under- or overestimation of biological activity such as respiration or photosynthesis. Especially in the case of small biological net gas exchange rates or gas accumulation phases during long environmental monitoring experiments, gas leakage fluxes could distort the analysis of the biogenic gas kinetics. Here we propose and demonstrate a general protocol for online correction of diffusion-driven gas leakage in plant chambers by simultaneous quantification of the inert tracer sulfur hexafluoride (SF6) and the investigated biogenic gases using enhanced Raman spectroscopy. By quantifying the leakage rates of carbon dioxide (CO2), methane (CH4), and hydrogen (H2) simultaneously with SF6 in the test chamber, their effective diffusivity ratios of approximately 1.60, 1.96, and 5.65 were determined, each related to SF6. Because our experiments suggest that the effective diffusivity ratios are reproducible for an individual static environmental chamber, even under varying concentration gradients and slight changes of the chamber sealing, an experimental method to quantify gas leakage fluxes by using effective diffusivity ratios and SF6 leakage fluxes is proposed. The method is demonstrated by quantifying the CO2 net exchange rate of a plant-soil ecosystem (Mirabilis jalapa). By knowing the effective chamber diffusivity ratio CO2/SF6 and the measured SF6 leakage rate during the experiment, the leakage contribution to the total CO2 exchange rate could be calculated and the biological net CO2 concentration change within the chamber atmosphere determined.

  12. LBA-ECO TG-07 Soil CO2 Flux by Automated Chamber, Para, Brazil: 2001-2003

    Science.gov (United States)

    R.K. Varner; M.M. Keller

    2009-01-01

    Measurements of the soil-atmosphere flux of CO2 were made at the km 67 flux tower site in the Tapajos National Forest, Santarem, Para, Brazil. Eight chambers were set up to measure trace gas exchange between the soil and atmosphere about 5 times a day (during daylight and night) at this undisturbed forest site from April 2001 to April 2003. CO2 soil efflux data are...

  13. The Crop Growth Research Chamber - A ground-based facility for CELSS research

    Science.gov (United States)

    Bubenheim, David L.; Luna, Phil M.; Wagenbach, Kimberly M.; Haslerud, Mark; Straight, Christian L.

    1989-01-01

    Crop Growth Research Chambers (CGRCs) are being developed as CELSS research facilities for the NASA/Ames Research Center. The history of the CGRC project is reviewed, noting the applications of CGRC research for the development of the Space Station. The CGRCs are designed for CELSS research and development, system control and integration, and flight hardware design and experimentation. The atmospheric and hydroponic environments of the CGRC system are described and the science requirements for CGRC environmental control are listed.

  14. Inhalation exposure methodology.

    OpenAIRE

    Phalen, R F; Mannix, R C; Drew, R T

    1984-01-01

    Modern man is being confronted with an ever-increasing inventory of potentially toxic airborne substances. Exposures to these atmospheric contaminants occur in residential and commercial settings, as well as in the workplace. In order to study the toxicity of such materials, a special technology relating to inhalation exposure systems has evolved. The purpose of this paper is to provide a description of the techniques which are used in exposing laboratory subjects to airborne particles and ga...

  15. Note: Fabrication of a fast-response and user-friendly environmental chamber for atomic force microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Han, Tingting; Song, Xiaoxue; Pan, Chengbin; Lanza, Mario, E-mail: mlanza@suda.edu.cn [Institute of Functional Nano & Soft Materials, Soochow University, Collaborative Innovation Center of Suzhou Nano Science & Technology, 199 Ren-Ai Road, Suzhou 215123 (China)

    2015-10-15

    The atomic force microscope is one of the most widespread tools in science, but many suppliers do not provide a competitive solution to make experiments in controlled atmospheres. Here, we provide a solution to this problem by fabricating a fast-response and user-friendly environmental chamber. We corroborate the correct functioning of the chamber by studying the formation of local anodic oxidation on a silicon sample (biased under opposite polarities), an effect that can be suppressed by measuring in a dry nitrogen atmosphere. The usefulness of this chamber goes beyond the example here presented, and it could be used in many other fields of science, including physics, mechanics, microelectronics, nanotechnology, medicine, and biology.

  16. Note: Fabrication of a fast-response and user-friendly environmental chamber for atomic force microscopes

    Science.gov (United States)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Han, Tingting; Song, Xiaoxue; Pan, Chengbin; Lanza, Mario

    2015-10-01

    The atomic force microscope is one of the most widespread tools in science, but many suppliers do not provide a competitive solution to make experiments in controlled atmospheres. Here, we provide a solution to this problem by fabricating a fast-response and user-friendly environmental chamber. We corroborate the correct functioning of the chamber by studying the formation of local anodic oxidation on a silicon sample (biased under opposite polarities), an effect that can be suppressed by measuring in a dry nitrogen atmosphere. The usefulness of this chamber goes beyond the example here presented, and it could be used in many other fields of science, including physics, mechanics, microelectronics, nanotechnology, medicine, and biology.

  17. Development of an environmental chamber for evaluating the performance of low-cost air quality sensors under controlled conditions

    Science.gov (United States)

    Papapostolou, Vasileios; Zhang, Hang; Feenstra, Brandon J.; Polidori, Andrea

    2017-12-01

    A state-of-the-art integrated chamber system has been developed for evaluating the performance of low-cost air quality sensors. The system contains two professional grade chamber enclosures. A 1.3 m3 stainless-steel outer chamber and a 0.11 m3 Teflon-coated stainless-steel inner chamber are used to create controlled aerosol and gaseous atmospheres, respectively. Both chambers are temperature and relative humidity controlled with capability to generate a wide range of environmental conditions. The system is equipped with an integrated zero-air system, an ozone and two aerosol generation systems, a dynamic dilution calibrator, certified gas cylinders, an array of Federal Reference Method (FRM), Federal Equivalent Method (FEM), and Best Available Technology (BAT) reference instruments and an automated control and sequencing software. Our experiments have demonstrated that the chamber system is capable of generating stable and reproducible aerosol and gas concentrations at low, medium, and high levels. This paper discusses the development of the chamber system along with the methods used to quantitatively evaluate sensor performance. Considering that a significant number of academic and research institutions, government agencies, public and private institutions, and individuals are becoming interested in developing and using low-cost air quality sensors, it is important to standardize the procedures used to evaluate their performance. The information discussed herein provides a roadmap for entities who are interested in characterizing air quality sensors in a rigorous, systematic and reproducible manner.

  18. The use of three-dimensional printing to produce in vitro slice chambers.

    Science.gov (United States)

    Hyde, James; MacNicol, Melanie; Odle, Angela; Garcia-Rill, Edgar

    2014-12-30

    In recent years, 3D printing technology has become inexpensive and simple enough that any lab can own and use one of these printers. We explored the potential use of 3D printers for quickly and easily producing in vitro slice chambers for patch clamp electrophysiology. Slice chambers were produced using five available plastics: ABS, PLA, Nylon 618, Nylon 680, and T-glase. These "lab-made" chambers were also made using stereolithography through a professional printing service (Shapeways). This study measured intrinsic membrane properties of neurons in the brain stem pedunculopontine nucleus (PPN) and layer V pyramidal neurons in retrosplenial cortex. Nylon 680 and T-glase significantly hyperpolarized PPN neurons. ABS increased input resistance, decreased action potential amplitude, and increased firing frequency in pyramidal cortical neurons. To test long term exposure to each plastic, human neuroblastoma SHSY5Y cell cultures were exposed to each plastic for 1 week. ABS decreased cell counts while Nylon 618 and Shapeways plastics eliminated cells. Primary mouse pituitary cultures were also tested for 24-h exposure. ABS decreased cell counts while Nylon 618 and Shapeways plastics dramatically decreased cell counts. Chambers can be quickly and inexpensively printed in the lab. ABS, PLA, Nylon 680, and T-glase plastics would suffice for many experiments instead of commercially produced slice chambers. While these technologies are still in their infancy, they represent a powerful addition to the lab environment. With careful selection of print material, slice chambers can be quickly and inexpensively manufactured in the lab. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Drift Chambers detectors; Detectores de deriva

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I.; Martinez laso, L.

    1989-07-01

    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.

  20. Vacuum chamber for intersection I-4

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Vacuum chamber for intersection I-4 of the ISR being assembled inside a wooden mock-up of the gap of the split-field magnet. The central round-cylinder section is provisional and is to be replaced by an elliptic-cylinder section to give more space vertically for installation of detectors. Supports for the central section are of carbon fibre composite.

  1. Using reverberation chambers for em measurements

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2010-01-01

    Reverberation chambers (RC) are being used for several decades. The main advantage is the high field strength which can be generated, with only modest power. In the last few years the use of RCs became much popular, for testing multi-path propagation for communication links, or testing the coupling

  2. Spark chambers in the Microcosm museum

    CERN Multimedia

    Patrice Loiez

    1990-01-01

    These spark chambers were displayed in CERN's permanent exhibition, Microcosm. These were particle detectors in which the tracks of particles would be seen by sparks created along the particle's path. While touring Microcosm, visitors can learn more about this and other detector methods both past and present.

  3. Intracapsular cataract extraction with anterior chamber intraocular ...

    African Journals Online (AJOL)

    Aim: To assess the visual outcome of cataract extraction with ACIOL implantation in a Nigerian hospital. Methods: The visual outcome of 50 eyes of 42 patients aged 40 years and above, out of 212 eyes that underwent intracapsular cataract extraction (ICCE) and anterior chamber intraocular lens (ACIOL) implantation, were ...

  4. Lifetime tests for MAC vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions. (LEW)

  5. Readout system for proportional wire chambers

    CERN Document Server

    Berst, J D; Metzger, G; Meyer, J M; Schultz, G

    1974-01-01

    The authors describe a MWPC read-out system intended for the hyperon experiments at CERN. Its structure is like the familiar CAMAC branch highway, but driven by a spark chamber readout module placed in CAMAC. The different parts of the equipment, which may read up to 4096 wires, and the test system are described. (5 refs).

  6. IKAR, a ionization chamber for WA9

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    This ionization chamber arrived at CERN from Leningrad for a high precision study of hadron elastic scattering by a CERN-Clermont-Ferrand-Leningrad-Lyon-Uppsala Collaboration in the H3 beam (WA9). G.A. Korolev (third from right) looks at the drawings.

  7. Presenting Chamber Music to Young Children

    Science.gov (United States)

    Smith, Terry Fonda

    2011-01-01

    The number of professional ensembles and organizations with dedicated outreach concerts has been steadily increasing over the past decade. More recently, educational concerts pairing chamber music with young children have been documented. The work presented in this article is a study in the efficacy and feasibility of this format. Various music…

  8. The arrival of the CLOUD chamber

    CERN Multimedia

    CERN AVC

    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.

  9. Prototype vacuum chamber for ISR intersection region

    CERN Multimedia

    1974-01-01

    The vacuum chambers at the ISR interaction regions had to be as transparent as possible to the secondary particles emerging from the collision points. Made from stainless steel or titanium, only a fraction of a millimeter thick, they were most delicate to handle.

  10. Prototype Vacuum Chamber for ISR Intersection Region

    CERN Multimedia

    1974-01-01

    The vacuum chambers at the ISR interaction region had to be as transparent as possible to the secondary particles emerging from the collision points. Made from stainless steel or titanium, only a fraction of a millimeter thick, they were most delicate to handle.

  11. Reproducibility of the chamber scarification test

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner

    1996-01-01

    The chamber scarification test is a predictive human skin irritation test developed to rank the irritation potential of products and ingredients meant for repeated use on normal and diseased skin. 12 products or ingredients can be tested simultaneously on the forearm skin of each volunteer. The t...

  12. GRCop-84 Development for Combustion Chamber Liners

    Science.gov (United States)

    Ellis, David; Nathal, Michael; Yun, Hee Man; Lerch, Bradley; Greenbauer-Seng, Leslie; Thomas-Ogbuji, Linus; Holmes, Richard

    2000-01-01

    The development, test, and thermophysical & mechanical properties of a GRCop-84 alloy for combustion chamber liners is discussed. Topics discussed include: History of GRCop-84 development, GRCop-84 thermal expansion, thermal conductivity of GRCop-84, yield strength of GRCop-84, GRCop-84 creep lives, GrCop-84 low cycle fatigue (LCF) lives, and hot fire testing of GRCop-84 spool pieces.

  13. The use of microholography in bubble chambers

    CERN Document Server

    Royer, H

    1981-01-01

    In-line holography has been used for the first time in a bubble chamber for the account of the CERN (Geneva, CH). The holograms were recorded with the help of a single-mode pulse laser. Bubble tracks of 25 microns in diameter have been reconstructed with a resolution of 2 microns. (12 refs).

  14. Responses of soybeans and wheat to elevated CO2 in free-air and open top chamber systems

    Science.gov (United States)

    With increasing demand for agricultural products, more confidence is needed concerning impacts of rising atmospheric CO2 on crop yields. Despite debate about the merits of free-air CO2 enrichment (FACE) and open top chamber (OTC) systems, there has been only one reported experiment directly compari...

  15. Development of special ionization chambers for a quality control program in mammography; Desenvolvimento de camaras de ionizacao especiais para controle de qualidade em mamografia

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jonas Oliveira da

    2013-07-01

    Mammography is an imaging method that uses X-rays. The use of ionization chambers in mammography quality control programs presents an essential role which is to verify whether the parameters of the patient exposure are correct. However, the commercial ionization chambers for dosimetry in mammography represent a high cost for small and medium size clinics that wish to have this equipment or for professionals that work with quality control programs. The innovative feature of this work was to develop ionization chambers for this purpose. In this work ionization chambers for X radiation beams in the mammography energy range were designed, constructed and characterized. The ionization chambers were tested in standard X radiation beams at the LCI/IPEN. The main characterization tests performed with the ionization chambers were: saturation curve, linearity of response, angular and energy dependence. The response stability tests of the ionization chambers were also conducted at the LCI, presenting results within 2.0 % for long-term stability. The results of the remaining tests are in accordance with international standards. These ionization chambers were also submitted to quality control tests of mammography equipment: linearity of the air kerma rates, determination of half-value layers and mean glandular doses. The results for air kerma rate linearity were less than 10 %, as recommended in international standards. The mean glandular dose obtained with the developed chambers presented values comparable to those of commercial ionization chambers tested, with an estimated variation within international standards. (author)

  16. Continuous soil respiration at the Prairie Heating and Elevated CO2 site using forced diffusion chambers

    Science.gov (United States)

    Pendall, E.; Brennan, A. L.; Risk, D. A.; Carrillo, Y.

    2012-12-01

    Temporal variations in soil respiration are regulated by changes in soil temperature, moisture and plant phenological activity. These drivers are expected to vary with climate changes including elevated atmospheric CO2 and warming, but it is unknown whether the relationships between the drivers and soil CO2 efflux change with climate change. We studied diurnal to seasonal patterns of soil respiration and its drivers in mixed C3/C4 grassland at the Prairie Heating and CO2 Enrichment (PHACE) site near Cheyenne, WY, where Free-Air CO2 Enrichment is applied at 600 ppm during daytime in the growing season, and temperature is elevated by 1.5/3 deg C day/night all year. We deployed pairs of forced diffusion (FD) chambers in plots with intact and plant-free grassland, exposed to elevated CO2, warming, and ambient climate (six treatments total). Fluxes from intact grassland plots reflected contributions from root and microbial respiration (referred to as soil respiration), while those from plant-free plots reflected only microbial respiration. Non-dispersive infrared CO2 sensors (Vaisala GMT222, Helsinki, Finland) were installed inside the chambers, which had rims inserted 2-cm into the soil. Three sensors were installed in chambers that were not in contact with the soil surface, which recorded atmospheric CO2 concentrations. Soil respiration rates were calculated as the concentration difference between the soil and air chambers times the forced diffusivity factor, which was set by the semi-permeable membrane and calibrated for individual chambers. The objectives of this research were to evaluate the feasibility of this method for determination of continuous fluxes in semi-arid grassland by comparison with established methods, and to compare temporal dynamics and response functions of soil respiration to environmental drivers across the six treatments. We found that fluxes from the forced diffusion chambers compared well with those from an established, closed, dynamic

  17. Automated correction on X-rays calibration using transmission chamber and LabVIEW{sup TM}

    Energy Technology Data Exchange (ETDEWEB)

    Betti, Flavio; Potiens, Maria da Penha Albuquerque, E-mail: fbetti@ipen.b, E-mail: mppalbu@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    Uncertainties during prolonged exposure times on X-rays calibration procedures at the Instruments Calibration facilities at IPEN may suffer from efficiency (and therefore intensity) variations on the industrial X-Ray generator used. Using a transmission chamber as an online reference chamber during the whole irradiation process is proposed in order to compensate for such error source. Also temperature (and pressure) fluctuations may arise from the performance limited calibration room air conditioning system. As an open ionization chamber, that monitor chamber does require calculation of a correction factor due to the temperature and pressure effects on air density. Sending and processing data from all related instruments (electrometer, thermometer and barometer) can be more easily achieved by interfacing them to a host computer running an especially developed algorithm using LabVIEW{sup TM} environment which will not only apply the proper correction factors during runtime, but also determine the exact length of time to reach a desired condition, which can be: time period, charge collected, or air kerma, based on the previous calibration of the whole system using a reference chamber traceable to primary standard dosimetry laboratories. When performing such calibration, two temperature sensors (secondary standard thermistors) are simultaneously used, one for the transmission chamber, and other for the reference chamber. As the substitution method is used during actual customer's calibration, the readings from the second thermistor can also be used when desired for further corrections. Use of LabVIEW{sup TM} programming language allowed for a shorter development time, and it is also extremely convenient to make things easier when improvements and modifications are called for. (author)

  18. Design of an environmentally controlled rotating chamber for bioaerosol aging studies

    Science.gov (United States)

    Verreault, Daniel; Duchaine, Caroline; Marcoux-Voiselle, Melissa; Turgeon, Nathalie; Roy, Chad J.

    2015-01-01

    A chamber was designed and built to study the long-term effects of environmental conditions on air-borne microorganisms. The system consists of a 55.5-L cylindrical chamber, which can rotate at variable speeds on its axis. The chamber is placed within an insulated temperature controlled enclosure which can be either cooled or heated with piezoelectric units. A germicidal light located at the chamber center irradiates at a 360° angle. Access ports are located on the stationary sections on both ends of the chamber. Relative humidity (RH) is controlled by passing the aerosol through meshed tubes surrounded by desiccant. Validation assay indicates that the interior temperature is stable with less than 0.5 °C in variation when set between 18 and 30 °C with the UV light having no effect of temperature during operation. RH levels set at 20%, 50% and 80% varied by 2.2%, 3.3% and 3.3%, respectively, over a 14-h period. The remaining fraction of particles after 18 h of suspension was 8.8% at 1 rotation per minute (rpm) and 2.6% at 0 rpm with the mass median aerodynamic diameter (MMAD) changing from 1.21 ± 0.04 μm to 1.30 ± 0.02 μm at 1 rpm and from 1.21 ± 0.04 μm to 0.91 ± 0.01 μm at 0 rpm within the same time period. This chamber can be used to increase the time of particle suspension in an aerosol cloud and control the temperature, RH and UV exposure; the design facilitates stationary sampling to be performed while the chamber is rotating. PMID:25055842

  19. A Cosmic Ray Measurement Facility for ATLAS Muon Chambers

    CERN Document Server

    Biebel, O; Boutemeur, M; Brandt, A; Dubbert, J; Duckeck, G; Elmsheuser, J; Fiedler, F; Hertenberger, R; Kortner, O; Nunnemann, T; Rauscher, F; Schaile, A D; Schieferdecker, P; Staude, A; Stiller, W; Ströhmer, R; Vertesi, R

    2003-01-01

    Monitored Drift Tube (MDT) chambers will constitute the large majority of precision detectors in the Muon Spectrometer of the ATLAS experiment at the Large Hadron Collider at CERN. For commissioning and calibration of MDT chambers, a Cosmic Ray Measurement Facility is in operation at Munich University. The objectives of this facility are to test the chambers and on-chamber electronics, to map the positions of the anode wires within the chambers with the precision needed for standalone muon momentum measurement in ATLAS, and to gain experience in the operation of the chambers and on-line calibration procedures. Until the start of muon chamber installation in ATLAS, 88 chambers built at the Max Planck Institute for Physics in Munich have to be commissioned and calibrated. With a data taking period of one day individual wire positions can be measured with an accuracy of 8.3 micrometers in the chamber plane and 27 micrometers in the direction perpendicular to that plane.

  20. Aging studies of resistive bulk Micromegas chambers for the ATLAS muon spectrometer upgrade

    CERN Document Server

    Spencer, Katie Louise

    2017-01-01

    A long-term operation study is presented as a probe of the aging properties of two bulk-resistive Micromegas chambers installed at the GIF$^{++}$ Gamma Irradiation Facility at CERN. Trends in the instantaneous chamber current, recorded over $\\approx$ 500 days of sustained exposure to the GIF$^{++}$ high intensity photon source, are analysed as a function of time in order to identify any signs of detector aging. As part of the study, additional variations in the current due to the changing external conditions of the chambers must be corrected for in order to isolate any aging effects. These include the changing chamber positions with respect to the photon source and the temperature and pressure fluctuations of the detector gas medium. Due to a number of subsets of the total irradiation period in which the exact detector positions are unknown, the aging study at the present time remains inconclusive. As a result, an alternative long-term aging study utilising the instantaneous chamber dark currents is suggested...

  1. Chamber personnel's use of Nitrox 50 during hyperbaric oxygen treatment: a quality study--research report.

    Science.gov (United States)

    Hansen, Marco B; Jansen, Tejs; Sifakis, Michael B; Hyldegaard, Ole; Jansen, Erik C

    2013-01-01

    We aimed to evaluate the feasibility and safety of using Nitrox 50 as breathing gas during attendance in a multiplace hyperbaric chamber. Paper logs between Jan.-Dec. 2011 were reviewed to analyze nitrogen gas-loading, actual bottom time, total bottom time and surface interval time. With the use of the Norwegian Diving Tables nitrogen gas-loading was converted to Repetitive Group Letters. Symptoms of decompression sickness and health problems related to hyperbaric exposures were registered at weekly staff meetings. The chamber personnel breathed chamber air or Nitrox 50. 1,207 hyperbaric exposures were distributed to five chamber attendants and technicians, 14 doctors, and six nurses. Nitrox 50 was inhaled on 978 occasions (81.0%). Median nitrogen gas-loading after first pressurization complied with Repetitive Group Letter A (range A-E), second to C (range A-F), third to D (range A-F), fourth to E (range C-H), fifth to F (range C-H), and sixth to E (range B-G). No symptoms of decompression sickness were reported (95% CI 0.00-0.33%). Breathing Nitrox 50 during repetitive hyperbaric sessions seems to be feasible and safe while meeting high demands in number of treatment sessions and patient flow and with fewer people employed in the hyperbaric unit.

  2. Chamber and field evaluations of air pollution tolerances of urban trees

    Energy Technology Data Exchange (ETDEWEB)

    Karnosky, D.F.

    1981-04-01

    Results are presented for a study of the relative air pollution tolerances of 32 urban-tree cultivars as determined by both chamber fumigations and field exposures. Tolerances to ozone and sulfur dioxide, alone and in combination, were determined using short-term, acute doses administered while the plants were inside a plastic fumigation chamber located inside the Cary Arboretum greenhouses. In a follow-up study still underway, representatives of the same cultivars were outplanted at four locations in the greater New York City area. To date, only oxidant-type injury has been observed on trees in the field plots. Cultivars tolerant to all chamber and field exposures were Acer platanoides Cleveland, Crimson King, Emerald Queen, Jade Glen, and Summershade; Acer rubrum Autumn Flame and Red Sunset; Acer saccharum Green Mountain and Temple's Upright; Fagus sylvatica Rotundifolia; Fraxinus pennsylvanica Summit; and Ginkgo biloba Fastigate and Sentry. Cultivars sensitive to ozone as determined by the chamber and field tests and that may serve as bioindicators of the presence of ozone were Gleditsia triacanthos inermis imperial and Platanus acerifolia Bloodgood.

  3. Dark Matter Search Results from the PICO-60 CF$_3$I Bubble Chamber

    CERN Document Server

    Amole, C; Asner, D M; Baxter, D; Behnke, E; Bhattacharjee, P; Borsodi, H; Bou-Cabo, M; Brice, S J; Broemmelsiek, D; Clark, K; Collar, J I; Cooper, P S; Crisler, M; Dahl, C E; Daley, S; Das, M; Debris, F; Dhungana, N; Farine, J; Felis, I; Filgas, R; Girard, F; Giroux, G; Grandison, A; Hai, M; Hall, J; Harris, O; Jin, M; Krauss, C B; Fallows, S; Lafrenière, M; Laurin, M; Lawson, I; Levine, I; Lippincott, W H; Mann, E; Maurya, D; Mitra, P; Neilson, R; Noble, A J; Plante, A; Podviianiuk, R B; Priya, S; Ramberg, E; Robinson, A E; Rucinski, R; Ruschman, M; Scallon, O; Seth, S; Simon, P; Sonnenschein, A; Štekl, I; Vàzquez-Jàuregui, E; Wells, J; Wichoski, U; Zacek, V; Zhang, J; Shkrob, I A

    2015-01-01

    New data are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF$_3$I and located in the SNOLAB underground laboratory. PICO-60 is the largest bubble chamber to search for dark matter to date. With an analyzed exposure of 92.8 live-days, PICO-60 exhibits the same excellent background rejection observed in smaller bubble chambers. Alpha decays in PICO-60 exhibit frequency-dependent acoustic calorimetry, similar but not identical to that reported recently in a C$_3$F$_8$ bubble chamber. PICO-60 also observes a large population of unknown background events, exhibiting acoustic, spatial, and timing behaviors inconsistent with those expected from a dark matter signal. These behaviors allow for analysis cuts to remove all background events while retaining $48.2\\%$ of the exposure. Stringent limits on WIMPs interacting via spin-dependent proton and spin-independent processes are set, and the interpretation of the DAMA/LIBRA modulation signal as dark matter inte...

  4. A contribution to the study of urinary cobalt in workers exposed to atmospheric concentrations close to limit values of exposure and to the fixation of new biological indices of exposure. Contribution a l'etude des cobalturies de salaries exposes a des concentrations atmospheriques proches des valeurs limites d'exposition et a la fixation d'index biologiques d'exposition

    Energy Technology Data Exchange (ETDEWEB)

    Catilina, M.J.; Catilina, P.; Pepin, D.; Alfieri, R.; Chamoux, A.; Gabrillargues, D. (Clermont-Ferrand-2 Univ., 63 - Aubiere (France))

    1994-01-01

    Findings of the studies undertaken to assess biological indices for daily occupational exposure to inhaled micro-particles of metal-cobalt are given. Two groups of workers were studied: - group A exposed to a mean daily concentration of 0.05 mg/m[sup 3] (present) (V.M.E.): - group B exposed to a mean daily concentration of 0.10 mg/m[sup 3] (previous V.M.E.). Cobalt granulometry was found to be constant: 98% particles with a diameter < 5 [mu]m. The urinary cobalt measured at the end of the working day as an index of clearance ([mu]g/g of urinary creatinine) is compared to a local control population's. The biological indices of exposure are given: Exposure to 0.05 mg/m[sup 3] (group A, N = 66), mean: 2.96 - median: 2.95 - D.S.: 1.552. Exposure to 0.10 mg/m[sup 3] (group B, N = 50), mean: 10.89 - median: 11 - D.S.: 2.316. Control population (group T, N = 71), mean: 2.478 - median: 2.5 - D.S.: 1.655. The urinary cobalt measured in group A at the end of the working day is not significantly different from the controls'. But it is significantly different from group B. The ability of urinary cobalt to distinguish between the two types of environment is studied by method of probability. With a urinary cobalt < 5.5 [mu]g/g creat. the worker is most certainly exposed to atmospheric concentrations [<=] 0.05 mg/m[sup 3]. For 5.5 [mu]g/g creat. a 0.05 mg/m[sup 3] exposure is given with 1% risk of error. With a urinary cobalt ranging from 7.5 [mu]g/g creat. to 15 [mu]g/g, the worker is most certainly exposed to a 0.10 mg/m[sup 3] atmospheric concentration. For 7.5 [mu]g/g creat. a 0.10 mg/m[sup 3] exposure is proposed with 1% risk of error. For a 6.5 [mu]g/g creat. urinary cobalt at the end of the working day, the exposure might as well be group A's as the group B's. This case is rarely seen. The concept of limit biological index of exposure is discussed. (authors). 20 refs., 2 tabs., 2 figs.

  5. Anterior chamber fixation of a posterior chamber intraocular lens: A novel technique

    Directory of Open Access Journals (Sweden)

    A Sahap Kükner

    2014-01-01

    Full Text Available We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL in the anterior chamber (AC with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.

  6. Achievable field strength in reverberation chambers

    Directory of Open Access Journals (Sweden)

    N. Eulig

    2003-01-01

    Full Text Available Feldvariable Kammern (FVK, engl.: modestirred- chamber werden unter anderem für EMV-Störfestigkeitsprüfungen verwendet. Ein häufig genanntes Argument, das die Einführung dieser Kammern als normgerechte Prüfumgebung vorantreiben soll, ist eine hohe Feldstärke, die im Vergleich zu anderen Testumgebungen mit relativ moderaten HF-Leistungen erreicht werden kann. Besonders für sicherheitskritische Geräte, wie Komponenten aus der Avionik- oder KFZ-Industrie, sind heutzutage Testfeldstärken von mehreren 100 V/m notwendig. Derart hohe Feldstärken können in Umgebungen, die ein ebenes Wellenfeld erzeugen oder nachbilden, nur mit großen HFLeistungen generiert werden. Durch die Resonanzeigenschaften einer FVK können demgegenüber mit sehr viel weniger Leistung und damit Verstärkeraufwand vergleichbare Werte der Feldstärke erzeugt werden. Allerdings sinkt mit zunehmendem Volumen die erreichbare Feldstärke bei gleicher Speiseleistung. Idealerweise sollen Feldvariable Kammern bei möglichst niedrigen Frequenzen für EMVTests nutzbar sein, was jedoch ein großes Kammervolumen erfordert. Das Problem, bei niedrigen Frequenzen hohe Feldstärken erzeugen zu können, relativiert deshalb den Vorteil von FVKn gegenüber bekannten Testumgebungen bei niedrigen Testfrequenzen. Der Posterbeitrag erläutert, welche Feldstärken in verschieden großen Feldvariablen Kammern beim Einspeisen einer bestimmten hochfrequenten Leistung erreicht werden können. Anhand dieser Ergebnisse wird aufgezeigt, oberhalb welcher Grenzfrequenz eine Anwendung von FVKn nur sinnvoll erscheint. Mode-stirred chambers (MSCs can be used for radiated immunity tests in EMC testing. Advantageous compared to conventional test methods is the high field strength which can here be generated with less RF-Power. This point is often the main argument for pushing the standardization of MSCs as an other EMC testing environment. Especially for safety-critical electronic equipment like avionic or

  7. Structure of wet specimens in electron microscopy. Improved environmental chambers make it possible to examine wet specimens easily.

    Science.gov (United States)

    Parsons, D F

    1974-11-01

    image intensifiers can bring the observation dose below that required to stop cell motility. Use of a timed, pulsed deflector system enables sufficiently short exposures to be obtained to eliminate blurring due to Brownian motion. Environmental chambers have enhanced the possibilities of electron diffraction analysis of minute crystals and ordered biological structures. High-resolution electron diffraction patterns (especially kinematic) of protein crystals can only be obtained in a wet environment. Hence, it may now be possible to obtain undistorted images of protein molecules. Moreover, by subjecting diffraction patterns to image-iterative techniques (56), it will be possible to phase the electron diffraction patterns to give a calculated image with a higher resolution than that which can be produced by electron microscope objective lenses. Environmental chambers offer exciting prospects for the determination of water structure and water and ice nucleation (atmospheric science). Nucleation data near the molecular level have been badly needed for some time. The application of environmental chambers in industrial chemistry, for example, in studies of polymerization, catalysis, and corrosion, are awaiting exploration. They offer an unusual approach to measurements of reaction kinetics through images that should be both sensitive and rapid.

  8. RAPID COMMUNICATION: Conducting triangular chambers for EMC measurements

    Science.gov (United States)

    Huang, Yi

    1999-03-01

    Conducting rectangular chambers have been used extensively for electromagnetic compatibility (EMC) shielding and measurement applications. In this communication, conducting triangular chambers are investigated as an alternative structure for rectangular EMC reverberation chambers, which are becoming an increasingly important and powerful tool for both radiated immunity and emission tests. A prime consideration of designing such a system is the total possible number of modes inside the chamber. A new approach is introduced to obtain this parameter for three different triangular chambers. The initial study has demonstrated that triangular chambers may offer better performance in some cases than their rectangular counterparts.

  9. Metallic spherical anechoic chamber for antenna pattern measurement

    Science.gov (United States)

    Farahbakhsh, Ali; Khalaj-Amirhosseini, Mohammad

    2016-08-01

    Anechoic chambers are used for indoor antenna measurements. The common method of constructing an anechoic chamber is to cover all inside walls by the electromagnetic absorbers. In this paper, a fully metallic spherical chamber structure is presented in which the propagation of the electromagnetic waves inside the chamber is controlled and they are guided to an absorber. In the proposed method, an appropriate quiet zone is obtained, and unlike ordinary anechoic chambers, the absorber usage amount is reduced greatly. The performance of the chamber is evaluated by simulation. The results show that the proposed method could provide a useful technique for the indoor antenna measurements.

  10. Hypoxia stress test reveals exaggerated cardiovascular effects in hypertensive rats after exposure to the air pollutant acrolein.

    Science.gov (United States)

    Perez, Christina M; Ledbetter, Allen D; Hazari, Mehdi S; Haykal-Coates, Najwa; Carll, Alex P; Winsett, Darrell W; Costa, Daniel L; Farraj, Aimen K

    2013-04-01

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in susceptible populations. Despite increased risk, adverse responses are often delayed and require additional stress tests to reveal latent effects of exposure. The goal of this study was to use an episode of "transient hypoxia" as an extrinsic stressor to uncover latent susceptibility to environmental pollutants in a rodent model of hypertension. We hypothesized that exposure to acrolein, an unsaturated aldehyde and mucosal irritant found in cigarette smoke, diesel exhaust, and power plant emissions, would increase cardiopulmonary sensitivity to hypoxia, particularly in hypertensive rats. Spontaneously hypertensive and Wistar Kyoto (normotensive) rats, implanted with radiotelemeters, were exposed once for 3h to 3 ppm acrolein gas or filtered air in whole-body plethysmograph chambers and challenged with a 10% oxygen atmosphere (10min) 24h later. Acrolein exposure increased heart rate, blood pressure, breathing frequency, and minute volume in hypertensive rats and also increased the heart rate variability parameter LF, suggesting a potential role for increased sympathetic tone. Normotensive rats only had increased blood pressure during acrolein exposure. The hypoxia stress test after acrolein exposure revealed increased diastolic blood pressure only in hypertensive rats and increased minute volume and expiratory time only in normotensive rats. These results suggest that hypertension confers exaggerated sensitivity to air pollution and that the hypoxia stress test is a novel tool to reveal the potential latent effects of air pollution exposure.

  11. An uncommon variant of double-chambered right ventricle masquerading as double-chambered left ventricle.

    Science.gov (United States)

    Baritakis, Nikolaos; Grapsas, Nikolaos; Kotsalos, Andreas; Davlouros, Periklis

    2018-02-01

    We present a rare case of a double-chambered right ventricle masquerading as a double-chambered left ventricle, which was found incidentally on cardiac imaging in an adult female patient with atypical chest pain. The most common form of double-chambered right ventricle is characterized by compartmentalization of the right ventricle by muscular bands into 2 distinct chambers. The main features of this malformation are a pressure gradient between the 2 compartments, and the frequent (up to 90%) association with a membranous ventricular septal defect. In our case, the muscular band dividing the right ventricle was located in the inferoseptal part of the latter, creating a diminutive cavity that had no communication with the main right ventricle but communicated with the left ventricle creating the false impression of a double-chambered left ventricle. This constitutes a rare variant of double-chambered right ventricle with unknown clinical implications. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  12. Air density dependence of the response of the PTW SourceCheck 4pi ionization chamber for125I brachytherapy seeds.

    Science.gov (United States)

    Torres Del Río, J; Tornero-López, A M; Guirado, D; Pérez-Calatayud, J; Lallena, A M

    2017-06-01

    To analyze the air density dependence of the response of the new SourceCheck 4pi ionization chamber, manufactured by PTW. The air density dependence of three different SourceCheck 4pi chambers was studied by measuring 125 I sources. Measurements were taken by varying the pressure from 746.6 to 986.6hPa in a pressure chamber. Three different HDR 1000 Plus ionization chambers were also analyzed under similar conditions. A linear and a potential-like function of the air density were fitted to experimental data and their achievement in describing them was analyzed. SourceCheck 4pi chamber response showed a residual dependence on the air density once the standard pressure and temperature factor was applied. The chamber response was overestimated when the air density was below that under normal atmospheric conditions. A similar dependence was found for the HDR 1000 Plus chambers analyzed. A linear function of the air density permitted a very good description of this residual dependence, better than with a potential function. No significant variability between the different specimens of the same chamber model studied was found. The effect of overestimation observed in the chamber responses once they are corrected for the standard pressure and temperature may represent a non-negligible ∼4% overestimation in high altitude cities as ours (700m AMSL). This overestimation behaves linearly with the air density in all cases analyzed. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Validation of a new whole-body cryotherapy chamber based on forced convection.

    Science.gov (United States)

    Bouzigon, Romain; Arfaoui, Ahlem; Grappe, Frédéric; Ravier, Gilles; Jarlot, Benoit; Dugue, Benoit

    2017-04-01

    Whole-body cryotherapy (WBC) and partial-body cryotherapy (PBC) are two methods of cold exposure (from -110 to -195°C according to the manufacturers). However, temperature measurement in the cold chamber during a PBC exposure revealed temperatures ranging from -25 to -50°C next to the skin of the subjects (using isolating layer placed between the sensor and the skin). This discrepancy is due to the human body heat transfer. Moreover, on the surface of the body, an air layer called the boundary layer is created during the exposure and limits heat transfer from the body to the cabin air. Incorporating forced convection in a chamber with a participant inside could reduce this boundary layer. The aim of this study was to explore the use of a new WBC technology based on forced convection (frontal unilateral wind) through the measurement of skin temperature. Fifteen individuals performed a 3-min WBC exposure at -40°C with an average wind speed of 2.3ms-1. The subjects wore a headband, a surgical mask, underwear, gloves and slippers. The skin temperature of the participants was measured with a thermal camera just before exposure, just after exposure and at 1, 3, 5, 10, 15 and 20min after exposure. Mean skin temperature significantly dropped by 11°C just after exposure (p<0.001) and then significantly increased during the 20-min post exposure period (p<0.001). No critically low skin temperature was observed at the end of the cold exposure. This decrease was greater than the mean decreases in all the cryosauna devices with reported exposures between -140°C and -160°C and those in two other WBC devices with reported exposures between -60°C and -110°C. The use of this new technology provides the ability to reach decreases in skin temperature similar to other technologies. The new chamber is suitable and relevant for use as a WBC device. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Time Domain Technique for Rapid, Broadband Measurement of Human Absorption Cross Section in a Reverberation Chamber

    OpenAIRE

    Robinson, Martin P; Zhang, Xiaotian; Flintoft, Ian D.

    2017-01-01

    Absorption cross section (ACS) of an object is used in stochastic power balance models, while human ACS is closely related to microwave dosimetry parameters such as specific absorption rate (SAR) and thus characterises exposure as well as effect of human bodies on multipath propagation. ACS, averaged over all directions of incidence, can be obtained in the frequency domain from the S-parameters of two antennas in a stirred-mode reverberation chamber; however, our new time domain method is fas...

  15. Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam

    CERN Document Server

    Arneodo, F.; Bonesini, M.; di Tigliole, A.Borio; Boschetti, B.; Bueno, A.; Calligarich, E.; Casagrande, F.; Cavalli, D.; Cavanna, F.; Cennini, P.; Centro, S.; Cesana, E.; Cline, D.; Curioni, A.; De Mitri, I.; De Vecchi, C.; Dolfini, R.; Ferrari, A.; Ghezzi, A.; Guglielmi, A.; Kisiel, J.; Mannocchi, G.; de la Ossa, A.Martinez; Matthey, C.; Mauri, F.; Montanari, C.; Navas, S.; Negri, P.; Nicoletto, M.; Otwinowski, S.; Paganoni, M.; Palamara, O.; Pepato, A.; Periale, L.; Mortari, G.Piano; Picchi, P.; Pietropaolo, F.; Puccini, A.; Pullia, A.; Ragazzi, S.; Rancati, T.; Rappoldi, A.; Raselli, G.L.; Redaelli, N.; Rondio, E.; Rubbia, A.; Rubbia, C.; Sala, P.R.; Sergiampietri, F.; Sobczyk, J.; Suzuki, S.; de Fatis, T.Tabarelli; Terrani, M.; Terranova, F.; Tonazzo, A.; Ventura, S.; Vignoli, C.; Wang, H.; Zalewska, A.

    2006-01-01

    We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.

  16. Study of the atmospheric chemistry of radon progeny in laboratory and real indoor atmospheres. Final project report

    Energy Technology Data Exchange (ETDEWEB)

    Hopke, P.K.

    1996-09-01

    This report completes Clarkson University`s study of the chemical and physical behavior of the {sup 218}Po atom immediately following its formation by the alpha decay of radon. Because small changes in size for activity in the sub-10 nm size range result in large changes in the delivered dose per unit exposure, this behavior must be understood if the exposure to radon progeny and it dose to the cells in the respiratory tract are to be fully assessed. In order to pursue this general goal, two areas of radon progeny behavior are being pursued; laboratory studies under controlled conditions to better understand the fundamental physical and chemical processes that affect the progeny`s atmospheric behavior and studies in actual indoor environments to develop a better assessment of the exposure of the occupants of that space to the size and concentration of the indoor radioactive aerosol. Thus, two sets of specific goals have been established for this project. The specific tasks of the controlled laboratory studies are (1) Determine the formation rates of {circ}OH radicals formed by the radiolysis of air following radon decay; (2) Examine the formation of particles by the radiolytic oxidation of substances like SO{sub 2}, ethylene, and H{sub 2}S to lower vapor pressure compounds and determine the role of gas phase additives such as H{sub 2}O and NH{sub 3} in determining the particle size; (3) Measure the rate of ion-induced nucleation using a thermal diffusion cloud chamber, and (4) Measure the neutralization rate of {sup 218}PoO{sub x}{sup +} in O{sub 2} at low radon concentrations.

  17. The physics of Resistive Plate Chambers

    CERN Document Server

    Riegler, Werner

    2004-01-01

    Over the last 3 years we investigated theoretical aspects of Resistive Plate Chambers (RPC) in order to clarify some of the outstanding questions on space charge effects, high efficiency of small gap RPCs, charge spectra, signal shape and time resolution. In a series of reports we analyzed RPC performance including all detector aspects covering primary ionization, avalanche multiplication, space charge effects, signal induction in presence of resistive materials, crosstalk along detectors with long strips and front-end electronics. Using detector gas parameters entirely based on theoretical predictions and physical models for avalanche development and space charge effects we are able to reproduce measurements for 2 and 0.3 mm RPCs to very high accuracy without any additional assumptions. This fact gives a profound insight into the workings of RPCs and also underlines the striking difference in operation regime when compared to wire chambers. A summary of this work as well as recent results on three-dimensiona...

  18. Introduction for Diffusion Chamber Culture Symposium

    Energy Technology Data Exchange (ETDEWEB)

    Carsten, A. L.

    1979-01-01

    The diffusion-chamber system has been applied to studies of cell kinetics, progenitor cell quantitation, humoral effects, immunological effects, cytogenetics, organogenesis, and the cellular effects of drugs and physical factors such as radiation, hypoxia, etc. Chamber contents have been analyzed by clot dissolution with measuring of cell content, limiting dilution evaluation, radionuclide utilization (tritiated thymidine labeling), growth of colony number, size and type, CFU-S or CFU-C content, or proliferation by secondary culture in mice or in vitro systems, and chromosome changes. Cell types ranging from embryonal tissues to adult normal and neoplastic tissues have been grown in hosts across species barriers. Advantages and disadvantages of this system are discussed.

  19. The KLOE drift chamber VCI 2001

    CERN Document Server

    Adinolfi, M; Ambrosino, F; Andryakov, A; Antonelli, A; Antonelli, M; Anulli, F; Bacci, C; Bankamp, A; Barbiellini, G; Bellini, F; Bencivenni, G; Bertolucci, Sergio; Bini, C; Bloise, C; Bocci, V; Bossi, F; Branchini, P; Bulychjov, S A; Cabibbo, G; Calcaterra, A; Caloi, R; Campana, P; Capon, G; Carboni, G; Cardini, A; Casarsa, M; Cataldi, G; Ceradini, F; Cervell, F; Cevenini, F; Chiefari, G; Ciambrone, P; Conetti, S; Conticelli, S; De Lucia, E; De Robertis, G; De Simone, P; De Zorzi, G; De Sangro, R; Dell'Agnello, S; Denig, A; Di Domenico, A; Di Donato, C; Di Falco, S; Doria, A; Drago, E; Elia, V; Erriquez, O; Farilla, A; Felici, G; Ferrari, A; Ferrer, M L; Finocchiaro, G; Forti, C; Franceschi, A; Franzini, P; Gao, M L; Gatti, C; Gauzzi, P; Giovannella, S; Golovatyuk, V; Gorini, E; Grancagnolo, F; Grandegger, W; Graziani, E; Guarnaccia, P; Han, H G; Han, S W; Huang, X; Incagli, M; Ingrosso, L; Jang, Y Y; Kim, W; Kluge, W; Kulikov, V; Lacava, F; Lanfranchi, G; Lee-Franzini, J; Lomtadze, F; Luisi, C; Mao Chen Sheng; Martemyanov, M; Matsyuk, M; Mei, W; Merola, L; Messi, R; Miscetti, S; Moalem, A; Moccia, S; Moulson, M; Murtas, F; Müller, S; Napolitano, M; Nedosekin, A; Pacciani, L; Pagès, P; Palutan, M; Panareo, M; Paoluzi, L; Pasqualucci, E; Passalacqua, L; Passaseo, M; Passeri, A; Patera, V; Petrolo, E; Petrucci, Guido; Picca, D; Pirozzi, G; Pistillo, C; Pollack, M; Pontecorvo, L; Primavera, M; Ruggieri, F; Santangelo, P; Santovetti, E; Saracino, G; Schamberger, R D; Schwick, C; Sciascia, B; Sciubba, A; Scuri, F; Sfiligoi, I; Shan, J; Silano, P; Spadaro, T; Spagnolo, S; Spiriti, E; Stanescu, C; Tong, G L; Tortora, L; Valente, E; Valente, P; Valeriani, B; Venanzoni, G; Veneziano, Stefano; Von Hagel, U; Wu, Y; Xie, Y G; Zhao, P P; Zhou, Y

    2002-01-01

    The main goal of the KLOE experiment at the Frascati DAPHINE phi-factory is the study CP violation in kaon decays. The tracking device of the experiment is a drift chamber whose dimensions, 4 m of diameter and 3.3 m length, provide a large acceptance volume for the decay products of low momentum K sub L (lambda sub L =3.4 m). A complete stereo geometry with 12.582 cells arranged in 58 layers guarantees a high and uniform efficiency in the reconstruction of the charged K sub L decays. Very light materials have been chosen both for the drift medium, a helium-based gas mixture, and for the mechanical structure, made of carbon fiber, to minimize multiple scattering and conversion of low-energy photons. The design requirements, the adopted solutions together with the calibration procedure and the tracking performances of the drift chamber are discussed.

  20. Diurnal variations in a sealed radon chamber

    Science.gov (United States)

    Gilboy, W. B.; James, P. R.; Farmer, C. P.; Beard, J. E.

    1990-12-01

    During experiments to calibrate a radon-in-air counter, some unexpected diurnal variations have been observed. Inside the sealed stainless-steel chamber of a nominal volume of 3 litres, ionised 218Po atoms from the alpha-decay of 222Rn are attracted by an electric field to a ZnS(Ag) scintillation screen via which subsequent α-decay events are detected. Results for this configuration are presented and also for a modified version in which the scintillation screen is replaced by a high-resolution α-detector. Ambient temperature changes were suspected to be responsible for the observed counting-efficiency variation and this has been confirmed by operating the wall of the chamber at various temperatures between 0°C and about 40°C, which revealed a positive temperature coefficient of ˜1%/°C at 25°C. Possible reasons for this effect are considered.

  1. Wire chambers with their magnetostrictive readout

    CERN Multimedia

    1974-01-01

    This set of wire chamber planes shaped as a cylinder sector was installed inside the magnet of a polarized spin target modified to allow as well momentum analysis of the produced particles. The experiment (S126) was set up by the CERN-Trieste Collaboration in the PS beam m9 to measure spin effects in the associated production of of a positive kaon and a positive Sigma by interaction of a positive pion with polarized protons.

  2. The Bern Infinitesimal Bubble Chamber (BIBC)

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    The chamber body was machined from a block of aluminium. The visible volume was cylindrical with 65 mm diameter and 35 mm depth. It was filled with propane or freon. It was meant as vertex detector in the search of short-lived particles. It was also used with in-line holography resulting in 8 µm bubble size and 9 cm depth of the field. See E. Ramseyer, B. Hahn and E. Hugentobler, Nucl. Instrum. Methods 201 (1982) 335.

  3. Efficient Determination of Reverberation Chamber Time Constant

    OpenAIRE

    Zhang, Xiaotian; Robinson, Martin P.; Flintoft, Ian D.; Dawson, John F.

    2017-01-01

    Determination of the rate of energy loss in a reverberation chamber is fundamental to many different measurements such as absorption cross-section, antenna efficiency, radiated power, and shielding effectiveness. Determination of the energy decay time-constant in the time domain by linear fitting the power delay profile, rather than using the frequency domain quality-factor, has the advantage of being independent of the radiation efficiency of antennas used in the measurement. However, determ...

  4. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    To minimise eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical strength, it was corrugated in a hydro-forming process. The cross-section was designed for maximum strength and maximum aperture. To accept particles with simultaneous large amplitudes in both planes, the cross-section approaches a rectangular shape (see also 7402463).

  5. Cell seeding chamber for bone graft substitutes

    OpenAIRE

    Hennig, J.; Schieker, Matthias; Seitz, H.

    2012-01-01

    There is an increasing demand for bone graft substitutes that are used as osteoconductive scaffolds in the treatment of bone defects and fractures. Achieving optimal bone regeneration requires initial cell seeding of the scaffolds prior to implantation. The cell seeding chamber is a closed assembly. It works like a sandglass. The position of the scaffold is between two reservoirs containing the fluid (e. g. blood). The fluid at the upper reservoir flows through the scaffold driven by gravity....

  6. Diurnal Variation of Anterior Chamber Flare

    Directory of Open Access Journals (Sweden)

    Mehmet Adam

    2015-04-01

    Full Text Available Objectives: To investigate the ideal time and reproducibility of anterior chamber flare measurements. Materials and Methods: Anterior chamber flare measurements were performed with laser flaremetre device at 8 am to 45 volunteers and these measurements were repeated on the same day at 12 pm and 4 pm. Results: Twenty-five (55.5% of the volunteers were women and 20 (44.5% were men; mean age was 28.67±7.40 (18-49 years. The mean anterior chamber flare measurements taken following the ophthalmologic examination were 5.94±1.41 foton/msn at 8 am, 5.65±1.45 foton/msn at 12 pm, and 5.79±1.20 foton/msn at 4 pm. No statistical difference was found between the measurements (p=0.08. Subgroup analysis according to eye color, revealed no significant difference between flare measurements in brown, hazel, and green eyes (p=0.21. Correlation analysis demonstrated association between age and all flare measurements within the day (r=0.24, p=0.03; r=0.41, p=0.01, r=0.27, p=0.01. Conclusion: No significant diurnal change was detected in the flare measurements of our study subjects but positive correlation with age was observed. Hence, all flare measurements within a day are reliable and have high repeatability in healthy subjects. (Turk J Ophthalmol 2015; 45: 52-5

  7. Close cathode chamber: Low material budget MWPC

    Science.gov (United States)

    Varga, Dezső; Kiss, Gábor; Hamar, Gergő; Bencédi, Gyula

    2013-01-01

    Performance of asymmetric-type MWPC-s are presented. In this structure, referred to as Close Cathode Chamber in an earlier study, the material budget is significantly reduced on one hand by the elimination of external support frame, on the other hand by thin detector walls. In this paper it is demonstrated that the outline is compatible with large size detectors (1 m wire length), maintaining mechanical and operation stability, with total weight of 3 kg (including support structure) for a half square meter surface. The detection efficiency and response time is shown to be sufficient for L0 triggering in the ALICE VHMPID layout. Reduced sensitivity to cathode deformations (due to internal overpressure as mechanical strain) is directly demonstrated. On small sized chambers, improvement of position resolution with analog readout is evaluated, reaching 0.09 mm RMS with 2 mm wide cathode segments. Simulation results on signal time evolutions are presented. With the above studies, comparison of classical MWPC-s and the Close Cathode Chamber design is performed in all major aspects.

  8. Menstrual history in altitude chamber trainees.

    Science.gov (United States)

    Schirmer, J U; Workman, W T

    1992-07-01

    Previous studies have determined a higher rate of altitude-induced decompression sickness (DCS) in women than in men. Women are reportedly at higher risk for developing DCS during menses. A study of menstrual history in women completing altitude chamber training without developing DCS has never been accomplished. The purpose of this study was to collect and analyze menstrual history in these women. Thirteen U.S. Air Force Aerospace Physiology Units participated in a USAF-approved survey for 1 year. After completing altitude chamber flights, data on age, day of menstrual cycle (DMC), birth control pill use (BCP), and mean durations of menstrual cycle and menses were collected. There were 508 responses analyzed. There was no differences between mean duration of menstrual cycle and menses in the Yes (Y) and No (N) BCP groups. Y and N BCP groups were equally distributed across the menstrual cycle. Women completing altitude chamber training without developing DCS appear to be evenly distributed across their menstrual cycle, with use of BCPs not affecting their susceptibility to DCS.

  9. Wire pad chamber for LHCb muon system

    CERN Document Server

    Botchine, B; Lazarev, V A; Sagidova, N; Vorobev, A P; Vorobyov, A; Vorobyov, Alexei

    2000-01-01

    2000-003 Wire pad chambers (WPC) have been proposed for the outer Region 4 of the LHCb Muon System. These are double gap MWPCs with small wire spacing allowing to obtain 99% detection efficiency in a 20 ns time window. The chambers have a rectangular shape with the vertical dimension from 20 cm in Station 1 to 30 cm in Station 5. The horizontal dimensions will be different with the maximal size of 3 meters in Station 5. The wires are in the vertical direction. The short wire length allows to use small wire spacing needed for high time resolution. Also, this helps to obtain the uniform gas gain over the whole chamber area. The WPC has one row of the wire pads formed by grouping wires in separate readout channels. Four WPC prototypes have been built at PNPI and tested in the PS beam at CERN. Here we report on the results from these tests. Also, the results of simulation of the WPC performance are presented.

  10. Testing fireproof materials in a combustion chamber

    Directory of Open Access Journals (Sweden)

    Kulhavy Petr

    2017-01-01

    Full Text Available This article deals with a prototype concept, real experiment and numerical simulation of a combustion chamber, designed for testing fire resistance some new insulating composite materials. This concept of a device used for testing various materials, providing possibility of monitoring temperatures during controlled gas combustion. As a fuel for the combustion process propane butane mixture has been used and also several kinds of burners with various conditions of inlet air (forced, free and fuel flows were tested. The tested samples were layered sandwich materials based on various materials or foams, used as fillers in fire shutters. The temperature distribution was measured by using thermocouples. A simulation of whole concept of experimental chamber has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. The result was to design chamber with a construction suitable, according to the international standards, achieve the required values (temperature in time. Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results – i.e. thermal distribution inside and heat release rate that has gone through the sample.

  11. Testing fireproof materials in a combustion chamber

    Science.gov (United States)

    Kulhavy, Petr; Martinec, Tomas; Novak, Ondrej; Petru, Michal; Srb, Pavel

    This article deals with a prototype concept, real experiment and numerical simulation of a combustion chamber, designed for testing fire resistance some new insulating composite materials. This concept of a device used for testing various materials, providing possibility of monitoring temperatures during controlled gas combustion. As a fuel for the combustion process propane butane mixture has been used and also several kinds of burners with various conditions of inlet air (forced, free) and fuel flows were tested. The tested samples were layered sandwich materials based on various materials or foams, used as fillers in fire shutters. The temperature distribution was measured by using thermocouples. A simulation of whole concept of experimental chamber has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. The result was to design chamber with a construction suitable, according to the international standards, achieve the required values (temperature in time). Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results - i.e. thermal distribution inside and heat release rate that has gone through the sample.

  12. Temperature changes in the pulp chamber during dentin ablation with Er:YAG laser

    Science.gov (United States)

    Zhang, Xianzeng; Zhao, Haibin; Zhan, Zhenlin; Guo, Wenqing; Xie, Shusen

    2012-12-01

    To examine the temperature changes in the pulp chamber during cavity preparation in dentin with the Er:YAG laser (2940 nm), a total 20 intact premolars teeth were divided into 4 groups for dentin ablation with different radiant exposures at 4Hz and 8Hz with and without water spray. A K-type thermocouple was used to monitor the temperature changes in pulp chamber during laser treatment. The total time of irradiation was 70 sec. the water spray rate was 3 mL/min. It showed that maximum temperature rise increases with the increasing of radiant exposure and pulse repetition rate and the additional water cooling during laser ablation can significantly reduce the temperature rise in pulp chamber which will benefit to avoid or reduce thermal damage to tooth structure and dental pulp. The highest rise of temperature in the pulp was achieved with 20 J/cm2 and 8 Hz (19.83°C ). For all sample without water spray, the rise of temperature was exceed 5 °C . In contrast, with water spray, the temperature rise in the pulp can be firmly controlled under 1°C. The results also indicated that ablation rate and efficiency can be enhanced by increasing the incident radiant exposure and pulse repetition rate, which simultaneously producing more heat accumulation in dental tissue and causing thermal damage to dental tissue. By applying an additional water spray, thermal damage can be significantly reduced in clinical application.

  13. Leipzig Ice Nucleation chamber Comparison (LINC): intercomparison of four online ice nucleation counters

    Science.gov (United States)

    Burkert-Kohn, Monika; Wex, Heike; Welti, André; Hartmann, Susan; Grawe, Sarah; Hellner, Lisa; Herenz, Paul; Atkinson, James D.; Stratmann, Frank; Kanji, Zamin A.

    2017-09-01

    Ice crystal formation in atmospheric clouds has a strong effect on precipitation, cloud lifetime, cloud radiative properties, and thus the global energy budget. Primary ice formation above 235 K is initiated by nucleation on seed aerosol particles called ice-nucleating particles (INPs). Instruments that measure the ice-nucleating potential of aerosol particles in the atmosphere need to be able to accurately quantify ambient INP concentrations. In the last decade several instruments have been developed to investigate the ice-nucleating properties of aerosol particles and to measure ambient INP concentrations. Therefore, there is a need for intercomparisons to ensure instrument differences are not interpreted as scientific findings.In this study, we intercompare the results from parallel measurements using four online ice nucleation chambers. Seven different aerosol types are tested including untreated and acid-treated mineral dusts (microcline, which is a K-feldspar, and kaolinite), as well as birch pollen washing waters. Experiments exploring heterogeneous ice nucleation above and below water saturation are performed to cover the whole range of atmospherically relevant thermodynamic conditions that can be investigated with the intercompared chambers. The Leipzig Aerosol Cloud Interaction Simulator (LACIS) and the Portable Immersion Mode Cooling chAmber coupled to the Portable Ice Nucleation Chamber (PIMCA-PINC) performed measurements in the immersion freezing mode. Additionally, two continuous-flow diffusion chambers (CFDCs) PINC and the Spectrometer for Ice Nuclei (SPIN) are used to perform measurements below and just above water saturation, nominally presenting deposition nucleation and condensation freezing.The results of LACIS and PIMCA-PINC agree well over the whole range of measured frozen fractions (FFs) and temperature. In general PINC and SPIN compare well and the observed differences are explained by the ice crystal growth and different residence times in

  14. Foliar Uptake of Elemental Iodine by Radish Plants -a Chamber Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong Ho; Lim, Kwang Muk; Jun, In; Keum, Dong Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    Radioiodine can be released into the air in the form of elemental iodine (I{sub 2}), which can be absorbed by crop plants through their stomata. Accordingly, foliar uptake of elemental radioiodine can be a significant pathway for man's exposure to internal radiations due to food consumption. Radish is highly consumed by Korean people but little is known about its foliar uptake of elemental radioiodine. In this study, an experiment was carried out using an exposure chamber in which radish plants were exposed to I{sub 2} vapor at different growth stages. Stable iodine was used for a surrogate of radioiodine.

  15. Anechoic chamber in industrial plants. [construction materials and structural design

    Science.gov (United States)

    Halpert, E.; Juncu, O.; Lorian, R.; Marfievici, D.; Mararu, I.

    1974-01-01

    A light anechoic chamber for routine acoustical measurements in the machine building industry is reported. The outer housing of the chamber consists of modules cast in glass fiber reinforced polyester resin; the inner housing consists of pyramidal modules cut out of sound absorbing slates. The parameters of this anechoic chamber facilitate acoustical measurements according to ISO and CAEM recommendations.

  16. The HERMES forward tracking chambers construction, operation, and aging effects

    CERN Document Server

    Brack, J T; Clark, S; Ely, J; Fox, B; Hofman, G J; Kinney, E R; Mercer, D J; Rakness, G; Ristinen, R A; Smythe, W R; Warner, D

    2001-01-01

    The design, construction and operation of the HERMES forward (front) tracking chambers and associated electronics are described. Resolution and limited aging tests have been performed on these drift chambers, which use an Ar/CF sub 4 /CO sub 2 (90 : 5 : 5) gas mixture. No degradation in chamber performance has been observed for a cumulative charge in excess of 9 C/cm.

  17. A cylindrical drift chamber with azimuthal and axial position readout

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Yam, Z.; Cummings, J.P.; Dowd, J.P.; Eugenio, P.; Hayek, M.; Kern, W.; King, E.; Shenhav, N.; Chung, S.U.; Hackenburg, R.W.; Olchanski, C.; Weygand, D.P.; Willutzki, H.J.; Brabson, B.B.; Crittenden, R.R.; Dzierba, A.R.; Gunter, J.; Lindenbusch, R.; Rust, D.R.; Scott, E.; Smith, P.T.; Sulanke, T.; Teige, S.; Denisov, S.; Dushkin, A.; Kochetkov, V.; Lipaev, V.; Popov, A.; Shein, I.; Soldatov, A.; Anoshina, E.V.; Bodyagin, V.A.; Demianov, A.I.; Gribushin, A.M.; Kodolova, O.L.; Korotkikh, V.L.; Kostin, M.A.; Ostrovidov, A.I.; Sarycheva, L.I.; Sinev, N.B.; Vardanyan, I.N.; Yershov, A.A.; Adams, T.; Bishop, J.M.; Cason, N.M.; Sanjari, A.H.; LoSecco, J.M.; Manak, J.J.; Shephard, W.D.; Stienike, D.L.; Taegar, S.A.; Thompson, D.R.; Brown, D.S.; Pedlar, T.; Seth, K.K.; Wise, J.; Zhao, D.; Adams, G.S.; Napolitano, J.; Nozar, M.; Smith, J.A.; Witkowski, M. [Massachusetts Univ., North Dartmouth, MA (United States)]|[Brookhaven National Laboratory, Upton, L.I., NY 11973 (United States)]|[Indiana University, Bloomington, IN 47405 (United States)]|[Institute for High Energy Physics, Protvino (Russian Federation)]|[Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation)]|[University of Notre Dame, Notre Dame, IN 46556 (United States)]|[Northwestern University, Evanston, IL 60208 (United States)]|[Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    1997-02-21

    A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in {pi}{sup -}p interactions. We describe the chamber`s design considerations, details of its construction, electronics, and performance characteristics. (orig.).

  18. 7 CFR 58.423 - Cheese vacuumizing chamber.

    Science.gov (United States)

    2010-01-01

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

  19. Bi-cone vacuum chamber in the ISR

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    The "bi-cone" vacuum chamber in ISR intersection I-7, for experiment R702. Made from 0.28 mm thick titanium, it was at its time the most transparent chamber ever built. Ian Wilson is standing next to the chamber. See also 7609219.

  20. Central Drift Chamber for rare kaon decay spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.; Blackmore, E.W.; Bryman, D.A.; Cresswell, J.; Numao, T.

    1986-02-01

    Design of the Central Drift Chamber for BNL experiment 787 and measurement of a rare kaon decay are discussed. A jet chamber type cell with 6 sense wires and no interspersed field wires has been designed to achieve good spatial resolution and efficiency in a 1 T magnetic field. Results of the testing of a prototype chamber are presented.

  1. Installation and Commissioning of the new GLM Implantation Chamber

    CERN Document Server

    Pohl, Christoph

    2016-01-01

    Summer student report about the work with the new implantation chamber for the GLM branch of ISOLDE. In the context of this project an API for the vacuum system of the new chamber was developed and implemented in web application that will be used to control the new implantation chamber at some point.

  2. 30 CFR 56.7807 - Flushing the combustion chamber.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Flushing the combustion chamber. 56.7807 Section 56.7807 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Rotary Jet Piercing Rotary Jet Piercing § 56.7807 Flushing the combustion chamber. The combustion chamber...

  3. 30 CFR 57.7807 - Flushing the combustion chamber.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Flushing the combustion chamber. 57.7807... and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7807 Flushing the combustion chamber. The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be...

  4. Engineering analyses of large precision cathode strip chambers for GEM

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, J.A.; Belser, F.C.; Pratuch, S.M.; Wuest, C.R. [Lawrence Livermore National Lab., CA (United States); Mitselmakher, G. [Superconducting Super Collider Lab., Dallas, TX (United States); Gordeev, A. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Johnson, C.V. [Lawrence Livermore National Lab., CA (United States)]|[Superconducting Super Collider Lab., Dallas, TX (United States); Polychronakos, V.A. [Brookhaven National Lab., Upton, NY (United States); Golutvin, I.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    1993-10-21

    Structural analyses of large precision cathode strip chambers performed up to the date of this publication are documented. Mechanical property data for typical chamber materials are included. This information, originally intended to be an appendix to the {open_quotes}CSC Structural Design Bible,{close_quotes} is presented as a guide for future designers of large chambers.

  5. Effects of rupatadine vs placebo on allergen-induced symptoms in patients exposed to aeroallergens in the Vienna Challenge Chamber.

    Science.gov (United States)

    Stuebner, Petra; Horak, Friedrich; Zieglmayer, René; Arnáiz, Eva; Leuratti, Chiara; Pérez, Iñaki; Izquierdo, Iñaki

    2006-01-01

    Rupatadine is a novel compound with potent dual antihistamine and platelet-activating factor antagonist activities and no sedative effects. To evaluate the efficacy of rupatadine, 10 mg once daily, and placebo on allergen-induced symptoms (including nasal congestion), nasal airflow, nasal secretion, and subjective tolerability in response to grass pollen in a controlled allergen-exposure chamber. In a randomized, double-blind, placebo-controlled, crossover trial, 45 patients with a history of seasonal allergic rhinitis received rupatadine or placebo every morning for 8 days in 2 different periods separated by a 14-day washout interval. On day 8 of each crossover period, patients underwent a 6-hour allergen exposure in the Vienna Challenge Chamber, where a constant and homogeneous concentration of aeroallergens was maintained. Subjective and objective assessments were performed online during the exposure. Subjective single and composite nasal and nonnasal symptoms were consistently less severe with rupatadine use than with placebo use starting from the first evaluation at 15 minutes to the end of the 6-hour Vienna Challenge Chamber challenge, with the most significant effects seen for nasal rhinorrhea, nasal itching, sneezing attacks, and total nasal symptoms (P rupatadine therapy than with placebo use (P rupatadine treatment was well tolerated. Rupatadine treatment is effective and well tolerated in patients with allergen-induced symptoms exposed to aeroallergens in a controlled exposure chamber.

  6. Safety observation of applying anterior chamber gas injection for unstable anterior chamber at the end of cataract surgery

    National Research Council Canada - National Science Library

    Yong-Zhi Huang; Tao Sun; Yu-Ting Zhi; Li Li; Lu-Ning Yan

    2015-01-01

    AIM: To observe the surgical effect, complications and assess the safety of applying anterior chamber injection of sterile air to treat instability of anterior chamber occurred at the end of cataract...

  7. A combination drift chamber/pad chamber for very high readout rates

    Energy Technology Data Exchange (ETDEWEB)

    Spiegel, L.; Cataldi, G.; Elia, V.; Mazur, P.; Murphy, C.T.; Smith, R.P.; Yang, W. [Fermi National Accelerator Lab., Batavia, IL (United States); Alexopoulos, T.; Durandet, C.; Erwin, A.; Jennings, J. [Wisconsin Univ., Madison, WI (United States); Antoniazzi, L.; Introzzi, G.; Lanza, A.; Liguori, G.; Torre, P. [Pavia Univ. (Italy)]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy); Arenton, M.; Conetti, S.; Cox, B.; Dukes, E.; Golovatyuk, V.; Hanlet, P.; McManus, A.; Nelson, K.; Recagni, M.; Segal, J.; Sun, J. [Virginia Univ., Charlottesville, VA (United States); Ballagh, C.; Bingham, H.; Kaeding, T.; Lys, J.; Misawa, S. [California Univ., Berkeley, CA (United States); Blankman, A.; Borodin, S.; Kononenko, W.; Newcomer, M.; Selove, W.; Trojak, T.; VanBerg, R.; Zhang, S.N. [Pennsylvania Univ., Philadelphia, PA (United States); Block, M.; Corti, G.; LeCompte, T.; Rosen, J.; Yao, T. [Northwestern Univ., Evanston, IL (United States); Boden, A.; Cline, D.; Ramachandran, S.; Rhoades, J.; Tokar, S. [California Univ., Los Angeles, CA (United States); Budagov, J.; Tsyganov, E. [Joint Inst. for Nuclear Research, Dubna (USSR); Cao, Z.L.; He, M.; Wang, C.; Wei, C.; Zhang, N. [Shandong Univ., Jinan, SD (China); Chen, T.Y.; Yao, N. [Nanjing Univ., JS (China); Clark, K.; Jenkins, M. [University of South Alabama, Mobile, AL (United States); Cooper, M. [Vanier Inst. of the Family, Ottawa, ON (Canada); Creti, P.; Gorini, E.; Grancagnolo, F.; Panareo, M. [Lecce Univ. (Italy)]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy); Fortney, L.; Kowald, W. [Duke Univ., Durham, NC (United States); Haire, M.; Judd, D.; Turnbull, L.; Wagoner, D. [Texas A and M Univ., Prairie View, TX (United States); Lau, K.; Mo, G. [Houston Univ., TX (United States); Trischuk, J. [McGill Univ., Montreal, PQ (Canada)

    1991-11-01

    Six medium-sized ({approx}1 {times} 2 m{sup 2}) drift chambers with pad and stripe readout have been constructed for and are presently operating in Fermi National Accelerator Laboratory experiment E-771. Each chamber module actually represents a pair of identical planes: two sets of anode wires, two sets of stripes, and two sets of pads. The wire planes are read out separately and represent X measurements in the coordinate system of the experiment. The twin stripe and pad planes are internally paired within the chamber modules; stripe signals represent Y measurements and pad signals combination X and Y measurements. Signals which develop on the stripes and pads are mirror (but inverted) images of what is seen on the wires. In addition to being used in the off-line pattern recognition, pad signals are also used as inputs to an on-line high transverse momentum (pt) trigger processor. While the techniques involved in the design and construction of the chambers are not novel, they may be of interest to experiments contemplating very large area, high rate chambers for future spectrometers.

  8. Atmospheric chemistry of CH3CHF2 (HFC-152a)

    DEFF Research Database (Denmark)

    Taketani, Fumikazu; Nakayama, Tomoki; Takahashi, Kenshi

    2005-01-01

    Smog chamber/Fourier transform infrared (FTIR) and laser-induced fluorescence (LIF) spectroscopic techniques were used to study the atmospheric degradation of CH3CHF2. The kinetics and products of the Cl(2P(3/2)) (denoted Cl) atom- and the OH radical-initiated oxidation of CH3CHF2 in 700 Torr...

  9. A novel non invasive measurement of hemodynamic parameters: Comparison of single-chamber ventricular and dual-chamber pacemaker

    Directory of Open Access Journals (Sweden)

    Ingrid M. Pardede

    2008-03-01

    Full Text Available We carried out a cross sectional study to analyze hemodynamic parameters of single-chamber ventricular pacemaker compared with dual-chamber pacemaker by using thoracic electrical bioimpedance monitoring method (Physio Flow™ - a novel simple non-invasive measurement. A total of 48 consecutive outpatients comprised of 27 single chamber pacemaker and 21 dual chamber were analyzed. We measured cardiac parameters: heart rate, stroke volume index, cardiac output index, estimated ejection fraction, end diastolic volume, early diastolic function ratio, thoracic fluid index, and systemic parameters: left cardiac work index and systemic vascular resistance index. Baseline characteristic and pacemaker indication were similar in both groups. Cardiac parameters assessment revealed no significant difference between single-chamber pacemaker and dual-chamber pacemaker in heart rate, stroke volume index, cardiac index, estimated ejection fraction, end-diastolic volume, thoracic fluid index. There was significantly higher early diastolic function ratio in single-chamber pacemaker compared to dual-chamber pacemaker: 92% (10.2-187.7% vs. 100.6% (48.7-403.2%; p=0.006. Systemic parameters assessment revealed significantly higher left cardiac work index in single-chamber group than dual-chamber group 4.9 kg.m/m² (2.8-7.6 kg.m/m² vs. 4.3 kg.m/m² (2.9-7.2 kg.m/m²; p=0.004. There was no significant difference on systemic vascular resistance in single-chamber compared to dual-chamber pacemaker. Single-chamber ventricular pacemaker provides similar stroke volume, cardiac output and left cardiac work, compared to dual-chamber pacemaker. A non-invasive hemodynamic measurement using thoracic electrical bioimpedance is feasible for permanent pacemaker outpatients. (Med J Indones 2008; 17: 25-32Keywords: Permanent pacemaker, single chamber, dual chamber, thoracic electrical bioimpedance, hemodynamic parameter

  10. Atmospheric neutrinos in Soudan 2.

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, M. C.; Soudan 2 Collaboration

    1999-03-30

    Soudan 2 has measured the atmospheric neutrino flavor ratio with 4.2 fiducial kiloton-years of exposure. It measures a flavor ratio of 0.66 {+-} 0.11(stat), inconsistent with the expected ratio but consistent with the hypothesis of neutrino oscillations and the Super-Kamiokande data. In a sample of events with good angular resolution, fits to the L/E distribution suggest that {Delta}m{sup 2} > 10{sup {minus}3} eV{sup 2}.

  11. Advanced Modified High Performance Synthetic Jet Actuator with Curved Chamber

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Su, Ji (Inventor); Jiang, Xiaoning (Inventor)

    2014-01-01

    The advanced modified high performance synthetic jet actuator with optimized curvature shape chamber (ASJA-M) is a synthetic jet actuator (SJA) with a lower volume reservoir or chamber. A curved chamber is used, instead of the conventional cylinder chamber, to reduce the dead volume of the jet chamber and increase the efficiency of the synthetic jet actuator. The shape of the curvature corresponds to the maximum displacement (deformation) profile of the electroactive diaphragm. The jet velocity and mass flow rate for the ASJA-M will be several times higher than conventional piezoelectric actuators.

  12. String quartet chamber music : the personal way of music development

    OpenAIRE

    Montant, Laure

    2012-01-01

    The subject of this thesis is about chamber music and more specifically string quartet. How and why chamber music should be a real part of a musician’s life. In the introduction, it is explained why it is important to play chamber music and what qualities a musician needs to be good at it. Then a description of what is chamber music litterally is exposed. The history recounts what was chamber music from its early beginings until our days and why it has so much evolves. About interpretation, t...

  13. Cost advantage of dual-chamber versus single-chamber cardioverter-defibrillator implantation.

    Science.gov (United States)

    Goldberger, Zachary; Elbel, Brian; McPherson, Craig A; Paltiel, A David; Lampert, Rachel

    2005-09-06

    The purpose of this study was to determine the least expensive strategy for device selection in patients receiving implantable cardioverter-defibrillators (ICDs). Device cost for a single-chamber ICD is less than an atrioventricular (dual-chamber) ICD (AV-ICD); however, some patients without clinical need for AV-ICD at implantation might require a later upgrade, potentially offsetting the initial cost advantage of the single-chamber device. Decision analysis was used to estimate expected resource utilization costs of three alternative implantation strategies: 1) single-chamber device in all, with later upgrade to AV-ICD if needed; 2) initial implantation of an AV-ICD in all; and 3) targeted device selection on the basis of results of electrophysiologic testing (presence or absence of induced bradyarrhythmias or atrial arrhythmias). Clinical base estimates were obtained from retrospective review of all patients receiving ICDs between June 1997 and July 2001 at a single university hospital. Economic inputs were collected from national and single-center sources. In patients without other indications for electrophysiologic study (EPS), the expected per-person cost was least with the strategy of universal initial AV-ICD implantation (36,232 dollars) compared with initial single-chamber ICD/upgrade as needed (39,230 dollars) or EPS-guided selection (41,130 dollars). Sensitivity analyses demonstrated that universal AV-ICD implantation remained least expensive with upgrade rates as low as 10%. At a 5% upgrade rate, AV-ICD remained cheapest if the device cost-differential narrowed to 1,568 dollars. For patients undergoing EPS for risk assessment, EP-guided selection was least expensive. The strategy of universal AV-ICD implantation, which provides the benefits of dual-chamber capability while obviating any potential need for future upgrade, is the least costly strategy for most patient populations receiving ICDs.

  14. 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.

  15. Liquid rocket combustion chamber acoustic characterization

    Directory of Open Access Journals (Sweden)

    Cândido Magno de Souza

    2010-09-01

    Full Text Available Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acoustic mode, combustion instability can be generated. On one hand, this instability can lead to ballistic pressure changes, couple with other propulsion systems such as guidance or thrust vector control, and in the worst case, cause motor structural failure. In this case, measures, applying acoustic techniques, must be taken to correct/minimize these influences on the combustion. The combustion chamber acoustic behavior in operating conditions can be estimated by considering its behavior in room conditions. In this way, acoustic tests can be easily performed, thus identifying the cavity modes. This paper describes the procedures to characterize the acoustic behavior in the inner cavity of four different configurations of a combustion chamber. Simple analytical models are used to calculate the acoustic resonance frequencies and these results are compared with acoustic natural frequencies measured at room conditions. Some comments about the measurement procedures are done, as well as the next steps for the continuity of this research. The analytical and experimental procedures results showed good agreement. However, limitations on high frequency band as well as in the identification of specific kinds of modes indicate that numerical methods able to model the real cavity geometry and an acoustic experimental modal analysis may be necessary for a more complete analysis. Future works shall also consider the presence of passive acoustic devices such as baffles and resonators capable of introducing damping and avoiding or limiting acoustic instabilities.

  16. 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.

  17. Exposure Forecaster

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Exposure Forecaster Database (ExpoCastDB) is EPA's database for aggregating chemical exposure information and can be used to help with chemical exposure...

  18. The Evolution and Development of Cephalopod Chambers and Their Shape.

    Science.gov (United States)

    Lemanis, Robert; Korn, Dieter; Zachow, Stefan; Rybacki, Erik; Hoffmann, René

    2016-01-01

    The Ammonoidea is a group of extinct cephalopods ideal to study evolution through deep time. The evolution of the planispiral shell and complexly folded septa in ammonoids has been thought to have increased the functional surface area of the chambers permitting enhanced metabolic functions such as: chamber emptying, rate of mineralization and increased growth rates throughout ontogeny. Using nano-computed tomography and synchrotron radiation based micro-computed tomography, we present the first study of ontogenetic changes in surface area to volume ratios in the phragmocone chambers of several phylogenetically distant ammonoids and extant cephalopods. Contrary to the initial hypothesis, ammonoids do not possess a persistently high relative chamber surface area. Instead, the functional surface area of the chambers is higher in earliest ontogeny when compared to Spirula spirula. The higher the functional surface area the quicker the potential emptying rate of the chamber; quicker chamber emptying rates would theoretically permit faster growth. This is supported by the persistently higher siphuncular surface area to chamber volume ratio we collected for the ammonite Amauroceras sp. compared to either S. spirula or nautilids. We demonstrate that the curvature of the surface of the chamber increases with greater septal complexity increasing the potential refilling rates. We further show a unique relationship between ammonoid chamber shape and size that does not exist in S. spirula or nautilids. This view of chamber function also has implications for the evolution of the internal shell of coleoids, relating this event to the decoupling of soft-body growth and shell growth.

  19. Anterior chamber intra ocular lens implantation.

    OpenAIRE

    Raju N

    1989-01-01

    The role of A.C. IOL in modern implant surgery has become somewhat debatable, since, the choice procedure to day is undoubtedly an ECCE with a PC lens implant preferably in the capsular bag. Even so, anterior chamber lens implantation has its definite indications. As such it is necessary for the implant surgeon to be familiar with the latest technique in this modality of surgery as well. Many of the complications of earlier rigid model AC IOLs were mainly due to defective lens design. With th...

  20. Posterior chamber intraocular lens dislocations and malpositions.

    Science.gov (United States)

    Obstbaum, S A; To, K

    1989-08-01

    Decentration and malposition of posterior chamber intraocular lenses (PC IOL) accounts for one of the remaining and unresolved conditions associated with the implantation of these lenses. This condition assumes importance since in approximately 50% of cases where a PC IOL is removed there is an aspect of improper positioning. The common types of malpositions are: pupil capture; sunset syndrome; sunrise syndrome; horizontal decentration; and the windshield wiper syndrome. This paper will explore the causes and management of these conditions and discuss the virtues of capsular bag implantation.

  1. Chamber service module (CSM1) for MDT

    CERN Document Server

    Binchi, P

    2002-01-01

    CSM-1 is the second and latest version of the high speed electronic unit whose primary task is to multiplex serial data from up to 18 ASD /TDC cards located at the ends of the Monitored Drift Tubes. Each CSM will capture data from all 24 channel TDC (AMT-2 units) of a given chamber and transfer it along a single optic fiber to the MROD, the event builder and readout driver. The core of the board is a Xilinx VirtexII FPGA which will use JTAG protocol (IEEE Std. 1149.1) for logic configuration parameter loading.

  2. Vacuum chamber for containing particle beams

    Science.gov (United States)

    Harvey, A.

    1985-11-26

    A vacuum chamber for containing a charged particle beam in a rapidly changing magnetic environment comprises a ceramic pipe with conducting strips oriented along the longitudinal axis of the pipe and with circumferential conducting bands oriented perpendicular to the longitudinal axis but joined with a single longitudinal electrical connection. When both strips and bands are on the outside of the ceramic pipe, insulated from each other, a high-resistance conductive layer such as nickel can be coated on the inside of the pipe.

  3. Microstrip gas chambers on implanted substrates

    Energy Technology Data Exchange (ETDEWEB)

    Pallares, A. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Barthe, S. [Laboratoire PHASE (UPR 292 du CNRS), 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 2 (France); Bergtold, A.M. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Brom, J.M. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Cailleret, J. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Christophel, E. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Coffin, J. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Eberle, H. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Fang, R. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Fontaine, J.C. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Geist, W. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Kachelhoffer, T. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Levy, J.M. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Mack, V. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Schunck, J.P. [Laboratoire PHASE (UPR 292 du CNRS), 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 2 (France); Sigward, M.H. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires

    1995-12-11

    We have studied the performance of several Microstrip Gas Chamber (MSGC) prototypes made on standard Desag D263 boron implanted glass. The purpose of the implantation is to reduce the surface resistance. The long term stability of this implantation has been measured under applied bias voltage. Comparative tests have been carried out on prototypes made on implanted and unimplanted detectors under electron ({sup 90}Sr) and X-ray (8 keV) irradiation. The total dose was approximately 7 mC/cm. (orig.).

  4. Liquid ionization chambers for LET determination

    DEFF Research Database (Denmark)

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

    Physik. 42, 303-344,        1913. [3]    KRAMERS, H.A.: On a modification of Jaffe's theory pf column-ionization. Physica. 10, 18,        665-675, 1952. [4]    CHU, J.C.H., GRANT, WH., ALMOND, P.R.: A liquid Ionization Chamber for neutron        dosimetry. Phys. Med. Biol. 6, 25, 1133-1148, 1980....

  5. Investigation on temperature separation and flow behaviour in vortex chamber

    Science.gov (United States)

    Matsuno, Yuhi; Fukushima, Yusuke; Matsuo, Shigeru; Hashimoto, Tokitada; Setoguchi, Toshiaki; Kim, Heuy Dong

    2015-04-01

    In the previous researches, it is known that the swirl flow in circular pipe causes the temperature separation. Recently, it is shown that the temperature separation occurs in a vortex chamber when compressed air are pumped into this device from the periphery. Especially, in a cavity installed in the periphery of the chamber, the highest temperature was observed. Therefore, it is expected that this device can be used as a heat source in the engineering field. In recent researches, the mechanism of temperature separation in vortex chamber has been investigated by some researchers. However, there are few researches for the effect of diameter and volume of vortex chamber, height of central rod and position of cavity on the temperature separation. Further, no detailed physical explanation has been made for the temperature separation phenomena in the vortex chamber. In the present study, the effects of chamber configuration and position of the cavity on temperature separation in the vortex chamber were investigated experimentally.

  6. Golden Jubilee photos: The first CERN bubble chamber

    CERN Multimedia

    2004-01-01

    In the 1950s and 1960s, bubble and spark chambers were the dominant experimental tools in high-energy physics. While spark chambers were usually built and fitted to specific experiments, bubble chambers were constructed as general purpose devices that could be used for a variety of experiments. At CERN, the bubble chamber programme started under Charles Peyrou in the late 1950s. The first of CERN's bubble chambers, a 30 cm hydrogen chamber, is seen here being inserted into its vacuum tank. The HBC30, as it was called, took its first beam from the SC in 1959. One of the first pictures taken, of a positive pion-proton interaction, began a long series of pretty images for which bubble chambers would become famous. When it stopped operating in spring 1962, the HBC30 had consumed 150 km of film in its 3 years of operation.

  7. Old-field Community, Climate and Atmospheric Manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Aimee Classen

    2009-11-01

    We are in the process of finishing a number of laboratory, growth chamber and greenhouse projects, analyzing data, and writing papers. The projects reported addressed these subjects: How do climate and atmospheric changes alter aboveground plant biomass and community structure; Effects of multiple climate changes factors on plant community composition and diversity: what did we learn from a 5-year open-top chamber experiment using constructed old-field communities; Do atmospheric and climatic change factors interact to alter woody seedling emergence, establishment and productivity; Soil moisture surpasses elevated CO{sub 2} and temperature in importance as a control on soil carbon dynamics; How do climate and atmospheric changes alter belowground root and fungal biomass; How do climate and atmospheric changes alter soil microarthropod and microbial communities; How do climate and atmospheric changes alter belowground microbial function; Linking root litter diversity and microbial functioning at a micro scale under current and projected CO{sub 2} concentrations; Multifactor climate change effects on soil ecosystem functioning depend on concurrent changes in plant community composition; How do climate and atmospheric changes alter aboveground insect populations; How do climate and atmospheric changes alter festuca endophyte infection; How do climate and atmospheric changes soil carbon stabilization.

  8. Experimental Modeling of Sterilization Effects for Atmospheric Entry Heating on Microorganisms

    Science.gov (United States)

    Schubert, Wayne W.; Spry, James A.; Ronney, Paul D.; Pandian, Nathan R.; Welder, Eric

    2012-01-01

    The objective of this research was to design, build, and test an experimental apparatus for studying the parameters of atmospheric entry heating, and the inactivation of temperature-resistant bacterial spores. The apparatus is capable of controlled, rapid heating of sample coupons to temperatures of 200 to 350 C and above. The vacuum chamber permits operation under vacuum or special atmospheric gas mixtures.

  9. Changes in deviation of absorbed dose to water among users by chamber calibration shift.

    Science.gov (United States)

    Katayose, Tetsurou; Saitoh, Hidetoshi; Igari, Mitsunobu; Chang, Weishan; Hashimoto, Shimpei; Morioka, Mie

    2017-07-01

    The JSMP01 dosimetry protocol had adopted the provisional 60Co calibration coefficient [Formula: see text], namely, the product of exposure calibration coefficient N C and conversion coefficient k D,X. After that, the absorbed dose to water D w standard was established, and the JSMP12 protocol adopted the [Formula: see text] calibration. In this study, the influence of the calibration shift on the measurement of D w among users was analyzed. The intercomparison of the D w using an ionization chamber was annually performed by visiting related hospitals. Intercomparison results before and after the calibration shift were analyzed, the deviation of D w among users was re-evaluated, and the cause of deviation was estimated. As a result, the stability of LINAC, calibration of the thermometer and barometer, and collection method of ion recombination were confirmed. The statistical significance of standard deviation of D w was not observed, but that of difference of D w among users was observed between N C and [Formula: see text] calibration. Uncertainty due to chamber-to-chamber variation was reduced by the calibration shift, consequently reducing the uncertainty among users regarding D w. The result also pointed out uncertainty might be reduced by accurate and detailed instructions on the setup of an ionization chamber.

  10. First dark matter limits from the COUPP 4 kg bubble chamber at a deep underground site

    Science.gov (United States)

    Fustin, Drew Anthony

    The COUPP 4 kg bubble chamber employs 4.0 kg of CF3I as a WIMP scattering target for use as a dark matter direct detection search. This thesis reports the first experimental results from operating this bubble chamber at the deep underground site (6000 m.w.e.) of SNO-LAB, near Sudbury, Ontario. Twenty dark matter candidate events were observed during an effective exposure of 553.0 kg-days, when operating the bubble chamber at three different bubble nucleation thresholds. These data are consistent with a neutron background internal to the detector. Characterization of this neutron background has led to the recommendation to replace two detector components to maximize dark matter signal sensitivity in a future run with this bubble chamber. Measurement of the gamma-ray flux has confirmed that this detector should not be sensitive to a gamma-induced background for more than three orders of magnitude below current sensitivity. The dark matter search data presented here set a new world-leading limit on the spin-dependent WIMP-proton scattering cross section and demonstrate significant sensitivity to spin-independent WIMP-nucleon scattering.

  11. Review of chamber design requirements for testing of personal protective clothing ensembles.

    Science.gov (United States)

    Gao, Pengfei; King, William P; Shaffer, Ronald

    2007-08-01

    This review focuses on the physical requirements for conducting ensemble testing and describes the salient issues that organizations involved in the design, test, or certification of personal protective equipment (PPE) and protective clothing ensembles need to consider for strategic planning. Several current and proposed PPE ensemble test practices and standards were identified. The man-in-simulant test (MIST) is the primary procedure used by the military to evaluate clothing ensembles for protection against chemical and biological warfare agents. MIST has been incorporated into the current editions of protective clothing and equipment standards promulgated by the National Fire Protection Association (NFPA). ASTM has recently developed a new test method (ASTM F 2588-06) for MIST evaluation of protective ensembles. Other relevant test methods include those described in International Organization for Standardization (ISO) standards. The primary differences among the test methods were the choice of test challenge material (e.g., sulfur hexafluoride, methyl salicylate, sodium chloride particles, corn oil, fluorophore-impregnated silica) and the exercise protocol for the subject(s). Although ensemble test methods and standards provide detailed descriptions of the test procedures, none give specific requirements for chamber design. A literature survey identified 28 whole-body exposure chambers that have been or could potentially be used for testing protective clothing ensembles using human test subjects. Median chamber size, median floor space, and median volume per subject were calculated from 15 chambers (involving human test subjects), where size information is available. Based on the literature survey of existing chambers and the review of the current and proposed standards and test methods, chamber design requirements will be dictated by the test methods selected. Due to widely different test conditions for aerosol/particulate and vapor ensemble testing, it is

  12. Operation of high rate microstrip gas chambers

    CERN Document Server

    Barr, A J; Bouclier, Roger; Capéans-Garrido, M; Dominik, Wojciech; Manzin, G; Million, Gilbert; Hoch, M; Ropelewski, Leszek; Sauli, Fabio; Sharma, A

    1996-01-01

    We describe recent measurements carried out in well controlled and reproducible conditions to help understanding the factors affecting the short and long term behaviour of Microstrip Gas Chambers. Special care has been taken concerning the gas purity and choice of materials used in the system and for the detectors construction. Detectors built on glasses with surface resistivity in the range $10^{13}-10^{15} \\Omega/\\Box$ have shown satisfactory performance as they do not show charging-up process at high rate and stand the large doses required for the future high luminosity experiments (~10 mC·cm-1·yr-1). Concerning the lifetime measurements, it has been observed that chambers manufactured on high-resistivity glass are far more susceptible of suffering ageing than detectors made on low resistivity, electron-conducting supports, independently of the metal used for the artwork (chromium or gold) at least in clean gas conditions. The successfully operation in the laboratory of detectors manufactured on diamond-...

  13. BEBC, the Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    The vessel of the Big European Bubble Chamber, BEBC, was installed at the beginning of the 1970s. The large stainless-steel vessel, measuring 3.7 metres in diameter and 4 metres in height, was filled with 35 cubic metres of liquid (hydrogen, deuterium or a neon-hydrogen mixture), whose sensitivity was regulated by means of a huge piston weighing 2 tonnes. During each expansion, the trajectories of the charged particles were marked by a trail of bubbles, where liquid reached boiling point as they passed through it. The first images were recorded in 1973 when BEBC, equipped with the largest superconducting magnet in service at the time, first received beam from the PS. In 1977, the bubble chamber was exposed to neutrino and hadron beams at higher energies of up to 450 GeV after the SPS came into operation. By the end of its active life in 1984, BEBC had delivered a total of 6.3 million photographs to 22 experiments devoted to neutrino or hadron physics. Around 600 scientists from some fifty laboratories through...

  14. Translimbal fixation of posterior chamber lenses.

    Science.gov (United States)

    Yospaiboon, Yosanan; Wongwai, Pantipa; Ratanapakorn, Tanapat; Sinawat, Suthasinee

    2005-11-01

    To evaluate the result of a surgical technique to insert and secure a standard posterior chamber lens through a simple limbal incision in eyes that had no capsular support or whose capsule was inadvertently ruptured during extracapsular cataract extraction. Retrospective review of the medical records of patients who underwent translimbal fixation of posterior chamber lenses according to age, gender, preoperative visual acuity, postoperative visual acuity, follow-up period and any complications, especially those that may be related to the surgical technique. Twelve patients were recruited in the present study. The patents' age ranged from 31 to 77 years, with a mean of 62.58 years. There were 9 male and 3 female patients. The preoperative visual acuity ranged from hand motion to counting fingers, and the postoperative visual acuity ranged from 6/6 to 6/24 except one patient who had postoperative visual acuity of counting fingers due to a pre-existing macular hole. The length of follow-up period ranged from 3 to 12 months, with a mean of 6.17 months. There was no clinically significant lens-related complication. This simple surgical technique controls the location of the needle entry and exit to decrease the risk of bleeding and increase the chance of ciliary sulcus placement. An inferior groove was made to bury the suture knot and was sutured closed to prevent the knot erosion through the conjunctiva.

  15. Suppressing drift chamber diffusion without magnetic field

    CERN Document Server

    Martoff, C J; Ohnuki, T; Spooner, N J C; Lehner, M

    2000-01-01

    The spatial resolution in drift chamber detectors for ionizing radiation is limited by diffusion of the primary electrons. A strong magnetic field along the drift direction is often applied (Fancher et al., Nucl. Instr. and Meth. A 161 (1979) 383) because it suppresses the transverse diffusion, improving the resolution but at considerable increase in cost and complexity. Here we show that transverse track diffusion can be strongly suppressed without any magnetic field. This is achieved by using a gas additive which reversibly captures primary ionization electrons, forming negative ions. The ions drift with thermal energies even at very high drift fields and low pressures (E/P=28.5 V/cm torr), and the diffusion decreases with increasing drift field. Upon arrival at the avalanche region of the chamber the negative ions are efficiently stripped and ordinary avalanche gain is obtained. Using this technique, r.m.s. transverse diffusion less than 200 mu m has been achieved over a 15 cm drift path at 40 torr with ze...

  16. Prototype for the ALEPH Time Projection Chamber

    CERN Multimedia

    1980-01-01

    This is a prototype endplate piece constructed during R&D for the ALEPH Time Projection Chamber (TPC). ALEPH was one of 4 experiments at CERN's 27km Large Electron Positron collider (LEP) that ran from 1989 to 2000. ALEPH's TPC was a large-volume tracking chamber, 4.4 metres long and 3.6 metres in diameter - the largest TPC in existance at the time. This object is one of the endplates of a “Kind” sector, the smallest of the three types of sectors. The patterns etched into the copper form the cathode pads that measured particle track coordinates in the r-phi direction. It included a laser calibration system, a gating system to prevent space charge buildup, and a new radial pad geometry to improve resolution. the ALEPH TPC allowed for precise momentum measurements of the high-momentum particles from W and Z decays. The following institutes participated: CERN, Athens, Glasgow, Mainz, MPI Munich, INFN-Pisa, INFN-Trieste, Wisconsin.

  17. Aging Investigation of CMS EMU Prototype Chambers

    CERN Document Server

    Ferguson*, T; Krivshich, Anatoli; Kuznetsova, Ekaterina; Lobachev, Evgeny; Mitselmakher, Guenakh; Schipunov, L

    1999-01-01

    The aging investigation results of CMS EMU prototype chambers are presented. Aging tests under sustained irradiation by a 90Sr 2 Ci were performed with three working gas mixtures Ar( 30%)+CO2( 50%)+CF4( 20%), Ar( 30%)+CO2( 70%) and Ar( 40%)+CO2( 50%)+CF4( 10%). For Ar( 30%)+CO2( 50%)+CF4( 20%) mixture gas gain reduction was not observed up to the accumulated charge Q = 13.56 C/cm. However, the dark current in the chamber was noticeable starting already from Q = 2 C/cm. The absence of the CF4 ( in the Ar/CO2 gas mixture) caused fast aging deterioration, and Q = 0.2 C/cm was enough to obtain 50% of the gas gain reduction. In the test with Ar( 40%)+CO2( 50%)+CF4( 10%) mixture the gas gain reduction and the dark current increase were not observed up to Q = 13.35 C/cm. Reduction of the gas flow rate to 0.1 volume per day caused 50% of the gain decrease due to the gas pollution by fragments of dissociated gas molecules. The gain restored after switching back to the 1 volume per day flow rate. Studies with electroni...

  18. COLDDIAG: A Cold Vacuum Chamber for Diagnostics

    CERN Document Server

    Casalbuoni, S; Gerstl, S; Grau, A W; Hagelstein, M; Saez de Jauregui, D; Boffo, C; Sikler, G; Baglin, V; Cox, M P; Schouten, J C; Cimino, R; Commisso, M; Spataro, B; Mostacci, A; Wallen, E J; Weigel, R; Clarke, J; Scott, D; Bradshaw, T; Jones, R; Shinton, I

    2011-01-01

    One of the still open issues for the development of superconducting insertion devices is the understanding of the beam heat load. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. The following diagnostics will be implemented: i) retarding field analyzers to measure the electron energy and flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. This will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG will be built to fit in a short straight section at ANKA. A first installation at the synchrotron light source Diamond is foreseen in June 2011. Here we describe the technical design report of this device and the planned measurements with beam.

  19. Effects of enhanced atmospheric ammonia on physiological characteristics of maize(Zea mays L.).

    Science.gov (United States)

    Chen, Xiaoli; Li, Shiqing

    2013-09-01

    Elevated atmospheric NH₃ may affect photosynthesis rates and biomass production of crops and the effect may be responsible for the soil nitrogen (N) levels. Plants were exposed to 0 and 1000 nL L⁻¹ with and without N (+N and - N) in open-top chambers (OTCs) to investigate effects of atmospheric NH₃ on photosynthetic and chlorophyll fluorescence parameters of maize plants. At two N levels, NH₃ exposure at 1000 nL L⁻¹ led to an increase in plant height, biomass production, net photosynthetic rates (P(n)) and stomatal conductance (g(s)) compared to ambient NH₃. Exposure to 1000 nL L⁻¹ NH₃ resulted in a significantly higher photochemical quenching (q(p)) and non-photochemical quenching (q(np)), while minimal fluorescence (F(o)), maximum fluorescence (F(m)) and maximum photochemical efficiency (F(v)/F(m)) were not affected. For shoots, N concentrations for - N-1000 and + N-1000 treatments were 49-50% and 26-30% higher, respectively, than those of - N-0 and + N-0 treatments. No visible damage was observed and plants growing on low soil N took up more leaf-derived N than those fertilised at higher N level. Therefore, atmospheric NH₃ can be considered as a quick fertiliser for crops and should be estimated in a further study with soil N fertilisers in order to reduce the dosage. © 2013 Society of Chemical Industry.

  20. Effect of crop development on biogenic emissions from plant populations grown in closed plant growth chambers

    Science.gov (United States)

    Batten, J. H.; Stutte, G. W.; Wheeler, R. M.

    1995-01-01

    The Biomass Production Chamber at John F. Kennedy Space Center is a closed plant growth chamber facility that can be used to monitor the level of biogenic emissions from large populations of plants throughout their entire growth cycle. The head space atmosphere of a 26-day-old lettuce (Lactuca sativa cv. Waldmann's Green) stand was repeatedly sampled and emissions identified and quantified using GC-mass spectrometry. Concentrations of dimethyl sulphide, carbon disulphide, alpha-pinene, furan and 2-methylfuran were not significantly different throughout the day; whereas, isoprene showed significant differences in concentration between samples collected in light and dark periods. Volatile organic compounds from the atmosphere of wheat (Triticum aestivum cv. Yecora Rojo) were analysed and quantified from planting to maturity. Volatile plant-derived compounds included 1-butanol, 2-ethyl-1-hexanol, nonanal, benzaldehyde, tetramethylurea, tetramethylthiourea, 2-methylfuran and 3-methylfuran. Concentrations of volatiles were determined during seedling establishment, vegetative growth, anthesis, grain fill and senescence and found to vary depending on the developmental stage. Atmospheric concentrations of benzaldehyde and nonanal were highest during anthesis, 2-methylfuran and 3-methylfuran concentrations were greatest during grain fill, and the concentration of the tetramethylurea peaked during senescence.

  1. Effects of outgassing of loader chamber walls on hydriding of thin films for commercial applications

    Energy Technology Data Exchange (ETDEWEB)

    Provo, James L., E-mail: jlprovo@verizon.net [Consultant, J.L. Provo Consulting, Trinity, Florida 34655-7179 (United States)

    2014-07-01

    An important aspect of understanding industrial processing is to know the characteristics of the materials used in such processes. A study was performed to determine the effects of hydriding chamber material on the degree of hydriding for the commercial production of thin film hydride targets for various research universities, commercial companies, and government national laboratories. The goal was to increase the degree of hydriding of various thin film hydrides and to study the vacuum environment during air-exposure hydriding. For this purpose, dynamic residual gas analysis during deuterium gas hydride processing was utilized with erbium thin films, employing a special set-up for direct dynamic hydride gas sampling during processing at elevated temperature and full loading gas pressure. Complete process data for (1) a copper–(1.83 wt. %)beryllium wet hydrogen fired passivated (600 °C–1 h) externally heated pipe hydriding chamber are reported. Dynamic residual gas analysis comparisons during hydriding are presented for hydriding chambers made from (2) alumina (99.8 wt. %), (3) copper (with an interior aluminum coating ∼10 k Å thick, and (4) for a stainless-steel air-fired passivated (900 °C–1 h) chamber. Dynamic data with deuterium gas in the chamber at the hydriding temperature (450 °C) showed the presence and growth of water vapor (D{sub 2}O) and related mixed ion species(H{sub 2}O{sup +}, HDO{sup +}, D{sub 2}O{sup +}, and OD{sup +}) from hydrogen isotope exchange reactions during the 1 h process time. Peaks at mass-to-charge ratios (i.e., m/e) of 12(C{sup +}), 16(CD{sub 2}{sup +}), 17(CHD{sub 2}{sup +}), and 18(CD{sub 3}{sup +}, OD{sup +}) increased for approximately the first half hour of a 1 h hydriding process and then approach steady state. Mass-to-charge peaks at 19(HDO{sup +}) and 20(D{sub 2}O{sup +}) continue to increase throughout the process cycle. Using the m/e = 20 (D{sub 2}O{sup +}) peak intensity from chamber (1

  2. Image quality, meteorological optical range, and fog particulate number evaluation using the Sandia National Laboratories fog chamber

    Science.gov (United States)

    Birch, Gabriel C.; Woo, Bryana L.; Sanchez, Andres L.; Knapp, Haley

    2017-08-01

    The evaluation of optical system performance in fog conditions typically requires field testing. This can be challenging due to the unpredictable nature of fog generation and the temporal and spatial nonuniformity of the phenomenon itself. We describe the Sandia National Laboratories fog chamber, a new test facility that enables the repeatable generation of fog within a 55 m×3 m×3 m (L×W×H) environment, and demonstrate the fog chamber through a series of optical tests. These tests are performed to evaluate system image quality, determine meteorological optical range (MOR), and measure the number of particles in the atmosphere. Relationships between typical optical quality metrics, MOR values, and total number of fog particles are described using the data obtained from the fog chamber and repeated over a series of three tests.

  3. TIG AISI-316 welds using an inert gas welding chamber and different filler metals: Changes in mechanical properties and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Pascual, M.; Salas, F.; Carcel, F.J.; Perales, M.; Sanchez, A.

    2010-07-01

    This report analyses the influence of the use of an inert gas welding chamber with a totally inert atmosphere on the microstructure and mechanical properties of austenitic AISI 316L stainless steel TIG welds, using AISI ER316L, AISI 308L and Inconel 625 as filler metals. When compared with the typical TIG process, the use of the inert gas chamber induced changes in the microstructure, mainly an increase in the presence of vermicular ferrite and ferrite stringers, what resulted in higher yield strengths and lower values of hardness. Its effect on other characteristics of the joins, such as tensile strength, depended on the filler metal. The best combination of mechanical characteristics was obtained when welding in the inert gas chamber using Inconel 625 as filler metal. (Author). 12 refs.

  4. A SIMPLE Bubble Chamber for Dark Matter Searches: Testing and Development

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, A.R.; Fernandes, A.C.; Marques, J.G.; Kling, A. [C2TN, Instituto Superior Tecnico, Universidade de Lisboa, E.N. 10 - km 139.7, 2695-066 Bobadela, LRS (Portugal); Felizardo, M.; Girard, T.A. [Centro de Fisica Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003, Lisbon (Portugal); Lazaro, I. [Laboratoire Souterrain a Bas Bruit, UMS 3538 UNS/UAPV/CNRS, 84400 Rustrel-Pays d' Apt (France); Puibasset, J. [Centre de Recherche sur la Matiere Divisee CNRS et Universite d' Orleans, 45071 Orleans, 02 (France)

    2015-07-01

    SIMPLE (Superheated Instrument for Massive Particle Experiments) is one of only three experiments worldwide in search of evidence of astroparticle dark matter (WIMPs) using halocarbon-loaded superheated liquid (SHL) detectors. The 2012 Phase II SIMPLE measurements yielded the most restrictive exclusion contour in the spin-dependent (SD) sector of WIMP-proton interactions from a direct search experiment at the time, overlapping for the first time results previously obtained only indirectly [1]. In order to remain competitive with other experiments in the field, the next phase measurement requires larger exposure over shorter observation times with significantly improved neutron shielding. To increase exposure, SIMPLE plans, as a first step, to replace its superheated droplet detectors (SDDs), each containing an active mass of about 15 g of halocarbon, with bubble chambers capable of holding up to 20 kg of active halocarbon mass. We report on the development of the first 1 kg halocarbon SIMPLE bubble chamber prototype, including chamber recompression system design and testing and initial acoustic detection of bubble formation. (authors)

  5. Thermal conditions in freezing chambers and prediction of the thermophysiological responses of workers

    Science.gov (United States)

    Raimundo, A. M.; Oliveira, A. V. M.; Gaspar, A. R.; Quintela, D. A.

    2015-11-01

    The present work is dedicated to the assessment of the cold thermal strain of human beings working within freezing chambers. To obtain the present results, both field measurements and a numerical procedure based on a modified version of the Stolwijk thermoregulation model were used. Eighteen freezing chambers were considered. A wide range of physical parameters of the cold stores, the workers clothing insulation, and the working and recovering periods were observed. The combination of these environmental and individual parameters lead to different levels of thermal stress, which were grouped under three categories. Some good practices were observed in the field evaluations, namely situations with appropriate level of clothing protection and limited duration of exposure to cold avoiding unacceptable level of hypothermia. However, the clothing ensembles normally used by the workers do not provide the minimum required insulation, which suggests the possibility of the whole body cooling for levels higher than admissible. The numerical predictions corroborate the main conclusions of the field survey. The results obtained with both methodologies clearly show that, for the low temperature of the freezing chambers, the clothing insulation is insufficient, the exposure periods are too long, and the recovering periods are inadequate. Thus, high levels of physiological strain can indeed be reached by human beings under such working environments.

  6. MOBILE ATMOSPHERIC SENSING

    Directory of Open Access Journals (Sweden)

    L. Wang

    2017-11-01

    Full Text Available Atmospheric quality dramatically deteriorates over the past decades around themetropolitan areas of China. Due to the coal combustion, industrial air pollution, vehicle waste emission, etc., the public health suffers from exposure to such air pollution as fine particles of particulates, sulfur and carbon dioxide, etc. Many meteorological stations have been built to monitor the condition of air quality over the city. However, they are installed at fixed sites and cover quite a small region. The monitoring results of these stations usually do NOT coincide with the public perception of the air quality. This paper is motivated to mimic the human breathing along the citys transportation network by the mobile sensing vehicle of atmospheric quality. To obtain the quantitative perception of air quality, the Environmental Monitoring Vehicle of Wuhan University (EMV-WHU has been developed to automatically collect the data of air pollutants. The EMV-WHU is equipped with GPS/IMU, sensors of PM2.5, carbon dioxide, anemometer, temperature, humidity, noise, and illumination, as well as the visual and infrared camera. All the devices and sensors are well collaborated with the customized synchronization mechanism. Each sort of atmospheric data is accompanied with the uniform spatial and temporal label of high precision. Different spatial and data-mining techniques, such as spatial correlation analysis, logistic regression, spatial clustering, are employed to provide the periodic report of the roadside air quality. With the EMV-WHU, constant collection of the atmospheric data along the Luoyu Road of Wuhan city has been conducted at the daily peak and non-peak time for half a year. Experimental results demonstrated that the EMV is very efficient and accurate for the perception of air quality. Comparative findings with the meteorological stations also show the intelligence of big data analysis and mining of all sorts of EMV measurement of air quality. It is

  7. Responses of fungal root colonization, plant cover and leaf nutrients to long-term exposure to elevated atmospheric CO2 and warming in a subarctic birch forest understory

    DEFF Research Database (Denmark)

    Olsrud, Maria; Carlsson, Bengt Å.; Svensson, Brita M.

    2010-01-01

    to the fungal symbionts. In this study, we investigated how ericoid mycorrhiza (ErM), fine endophytes (FE) and dark septate endophytes (DSE) in roots responded to elevated atmospheric CO2 concentrations and warming in the dwarf shrub understory of a birch forest in the subarctic region of northern Sweden...

  8. Development of pulmonary oxygen toxicity in rats after hyperoxic exposure

    Directory of Open Access Journals (Sweden)

    Siermontowski Piotr

    2014-06-01

    Full Text Available The aim of the study was to examine the effects of hyperbaric oxygen on lung aeration on an animal experimental model and compare the obtained results with the anticipated scope of damage to pulmonary parenchyma in humans under the same exposure conditions. The research was carried out on Black Hood rats that were kept in a hyperbaric chamber designed for animals in an atmosphere of pure oxygen and at overpressures of 0.15, 0.2, 0.3, 0.4, and 0.5 MPa for 1, 2 or 4 h. After sacrificing the animals, histopathological specimens were obtained encompassing cross-sections of entire lungs, which were subjected to qualitative and quantitative examination with the use of the 121-point Haug grid. A statistically significant decrease in pulmonary parenchyma was observed as a result of an increasing oxygen partial pressure as well as with prolonged exposure time. The intensification of changes observed was much higher than expected on the basis of calculations performed with the use of tables.

  9. Gas chromatography vs. quantum cascade laser-based N2O flux measurements using a novel chamber design

    Science.gov (United States)

    Brümmer, Christian; Lyshede, Bjarne; Lempio, Dirk; Delorme, Jean-Pierre; Rüffer, Jeremy J.; Fuß, Roland; Moffat, Antje M.; Hurkuck, Miriam; Ibrom, Andreas; Ambus, Per; Flessa, Heinz; Kutsch, Werner L.

    2017-03-01

    Recent advances in laser spectrometry offer new opportunities to investigate the soil-atmosphere exchange of nitrous oxide. During two field campaigns conducted at a grassland site and a willow field, we tested the performance of a quantum cascade laser (QCL) connected to a newly developed automated chamber system against a conventional gas chromatography (GC) approach using the same chambers plus an automated gas sampling unit with septum capped vials and subsequent laboratory GC analysis. Through its high precision and time resolution, data of the QCL system were used for quantifying the commonly observed nonlinearity in concentration changes during chamber deployment, making the calculation of exchange fluxes more accurate by the application of exponential models. As expected, the curvature values in the concentration increase was higher during long (60 min) chamber closure times and under high-flux conditions (FN2O > 150 µg N m-2 h-1) than those values that were found when chambers were closed for only 10 min and/or when fluxes were in a typical range of 2 to 50 µg N m-2 h-1. Extremely low standard errors of fluxes, i.e., from ˜ 0.2 to 1.7 % of the flux value, were observed regardless of linear or exponential flux calculation when using QCL data. Thus, we recommend reducing chamber closure times to a maximum of 10 min when a fast-response analyzer is available and this type of chamber system is used to keep soil disturbance low and conditions around the chamber plot as natural as possible. Further, applying linear regression to a 3 min data window with rejecting the first 2 min after closure and a sampling time of every 5 s proved to be sufficient for robust flux determination while ensuring that standard errors of N2O fluxes were still on a relatively low level. Despite low signal-to-noise ratios, GC was still found to be a useful method to determine the mean the soil-atmosphere exchange of N2O on longer timescales during specific campaigns. Intriguingly

  10. The EEE Project: Cosmic rays, multigap resistive plate chambers and high school students

    CERN Document Server

    Abbrescia, M.; Antolini, R; Avanzini, C; Baldini Ferroli, R; Bencivenni, G; Bossini, E; Bressan, E; Chiavassa, A; Cicalo, C; Cifarelli, L; Coccia, E; De Gruttula, D; De Pasquale, S; Di Giovanni, A; D'Incecco, M; Doroud, K; Dreucci, M; Fabbri, FL; Frolov, V; Garbini, M; Gemme, G; Gnesi, I; Gustavino, C; Hatzifotiadu, D; La Rocca, P; Li, S; Moro, R; Miozzi, S; Massai, M; Maggiora, A; Librizzi, F; Piragino, G; Pilo, F; Perasso, L; Paoletti, R; Righini, GC; Scapparone, E; Sartorelli, G; Romano, F; Serci, S; Selvi, M; Scribano, A; Riggi, F; Regano, A; Squarcia, S; Spandre, G; Toselli, F; Taiuti, M; Zichichi, A; Zouyevski, R; Williams, MCS; Votano, L; Siddi, E; Panareo, M

    2012-01-01

    The Gas Gain Monitoring (GGM) system of the Resistive Plate Chamber (RPC) muon detector in the Compact Muon Solenoid (CMS) experiment provides fast and accurate determination of the stability in the working point conditions due to gas mixture changes in the closed loop recirculation system. In 2011 the GGM began to operate using a feedback algorithm to control the applied voltage, in order to keep the GGM response insensitive to environmental temperature and atmospheric pressure variations. Recent results are presented on the feedback method used and on alternative algorithms.

  11. Dark Matter Search Results from the PICO-60 C$_3$F$_8$ Bubble Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C.; et al.

    2017-02-24

    New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C$_3$F$_8$ located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C$_3$F$_8$ exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than 1 event per month. A blind analysis of an efficiency-corrected 1167-kg-day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the WIMP-proton spin-dependent cross section at 3.4 $\\times$ 10$^{-41}$ cm$^2$ for a 30-GeV$\\thinspace$c$^{-2}$ WIMP, more than one order of magnitude improvement from previous PICO results.

  12. R&D of a SIMPLE bubble chamber for dark matter searches

    Directory of Open Access Journals (Sweden)

    Felizardo M.

    2016-01-01

    Full Text Available SIMPLE (Superheated Instrument for Massive ParticLe Experiments intends the realization and full field tests of a 25 kg, low background, low frequency-instrumented BC (Bubble Chamber, with data from the BC testing and a small array demonstration providing new physics results. We report on the development of a 1 kg freon BC prototype, including chamber recompression system design and testing with initial acoustic detection of bubble formation. Realization of full field tests leading to a 25 kg, overall 10−6 recoil evt/kgF/d background, low frequency-instrumented BC, incorporating several innovations designed, are intended to serve for an anticipated 2500 kgd exposure, resulting in new exclusion contours with sensitivities of 2 × 10−8 and 5 × 10−5 pb at 35 GeV in the SI and SD sector of the WIMP phase space, respectively.

  13. Characterization of Tandem systems of commercial ionization chambers for radiation dosimetry (radiotherapy level)

    CERN Document Server

    Galhardo, E P

    1998-01-01

    The use of X rays for radiotherapy purposes is of great importance for Medicine, and it is necessary to control periodically the performance of the ionization chambers and the radiation beams in order to obtain the best results. The verification of the beam characteristics is made by using standard dosimetry procedures which include the determination of the half-value layers and the exposure rates or the absorbed dose rates in air. Several Tandem systems were set up and tested, using commercial ionization chambers in the energy interval from 14 up to 130 KeV at the Instrumentation Calibration Laboratory of IPEN and at other three institutions, in substitution to the routine conventional procedure of determination of half-value layers using absorbers. The obtained results show the usefulness of these Tandem system for the routine dosimetric procedures of radiotherapy X radiation beams.

  14. Responses of sensitive and tolerant bush beans (Phaseolus vulgaris L.) to ozone in open-top chambers are influenced by phenotypic differences, morphological characteristics, and the chamber environment

    Energy Technology Data Exchange (ETDEWEB)

    Elagoez, Vahram [Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003 (United States)]. E-mail: velagoz@nsm.umass.edu; Manning, William J. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States)

    2005-08-15

    Responses of bush bean (Phaseolus vulgaris L.) lines 'S156' (O{sub 3}-sensitive) and 'R123' (O{sub 3}-tolerant), and cultivars 'BBL 290' (O{sub 3}-sensitive) and 'BBL 274' (O{sub 3}-tolerant) to ambient ozone (O{sub 3}) were investigated during the 2001 and 2002 growing seasons. Seedlings were grown in pots inside open-top chambers (OTCs), with charcoal filtered (CF) and non-filtered (NF) ambient air, and in non-chambered ambient air (AA) plots. Growth parameters from individual plants were evaluated after harvests at the end of vegetative (V{sub 4}) and reproductive (R{sub 10}) growth phases. Results at V{sub 4} indicated that CF did not provide additional benefits over NF in 'S156' in 2001 and 2002. In contrast, exposure to CF significantly impaired the growth of 'R123'. At the end of R{sub 10}, 'S156' produced more pods, most of which remained immature, and contained fewer seeds or were more frequently aborted, whereas pods produced in 'R123' reached pod maturation and senescence more consistently. Despite increased seed weights inside the OTCs, as observed in 'S156', differences between the two lines were insignificant when grown outside OTCs. Results from the 'BBL 290'/'BBL 274' pair, especially at V{sub 4} phase, remained inconclusive. Plant morphological characteristics, variabilities in environmental conditions, and 'chamber effects' inside OTCs were influential in determining plant response to ambient O{sub 3}. - Phenotypic differences, morphological characteristics, and 'chamber effects' inside OTCs are equally influential in determining the responses of beans to O{sub 3}.

  15. Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber

    Science.gov (United States)

    Liu, T.; Wang, X.; Deng, W.; Hu, Q.; Ding, X.; Zhang, Y.; He, Q.; Zhang, Z.; Lü, S.; Bi, X.; Chen, J.; Yu, J.

    2015-08-01

    In China, a rapid increase in passenger vehicles has led to the growing concern of vehicle exhaust as an important source of anthropogenic secondary organic aerosol (SOA) in megacities hard hit by haze. In this study, the SOA formation of emissions from two idling light-duty gasoline vehicles (LDGVs) (Euro 1 and Euro 4) operated in China was investigated in a 30 m3 smog chamber. Five photo-oxidation experiments were carried out at 25 °C with relative humidity at around 50 %. After aging at an OH exposure of 5 × 106 molecules cm-3 h, the formed SOA was 12-259 times as high as primary organic aerosol (POA). The SOA production factors (PF) were 0.001-0.044 g kg-1 fuel, comparable with those from the previous studies at comparable OH exposure. This quite lower OH exposure than that in typical atmospheric conditions might however lead to the underestimation of the SOA formation potential from LDGVs. Effective SOA yields in this study were well fit by a one-product gas-particle partitioning model but quite lower than those of a previous study investigating SOA formation from three idling passenger vehicles (Euro 2-4). Traditional single-ring aromatic precursors and naphthalene could explain 51-90 % of the formed SOA. Unspeciated species such as branched and cyclic alkanes might be the possible precursors for the unexplained SOA. A high-resolution time-of-flight aerosol mass spectrometer was used to characterize the chemical composition of SOA. The relationship between f43 (ratio of m/z 43, mostly C2H3O+, to the total signal in mass spectrum) and f44 (mostly CO2+) of the gasoline vehicle exhaust SOA is similar to the ambient semi-volatile oxygenated organic aerosol (SV-OOA). We plot the O : C and H : C molar ratios of SOA in a Van Krevelen diagram. The slopes of ΔH : C / ΔO : C ranged from -0.59 to -0.36, suggesting that the oxidation chemistry in these experiments was a combination of carboxylic acid and alcohol/peroxide formation.

  16. Investigation of mixing chamber for experimental FGD reactor

    Directory of Open Access Journals (Sweden)

    Novosád Jan

    2017-01-01

    Full Text Available This article deals with numerical investigation of flow and mixing of air and sulphur dioxide SO2 in designated mixing chamber. The mixing chamber is a part of experimental laboratory reactor designed for simulating the flue gas desulfurization (FGD process. Aim of this work is the numerical investigation of effect of different mixing chamber geometries to mixture composition, especially to mass fraction of sulphur dioxide. Using of similar concentration of sulphur dioxide in the experimental reactor as in the real process is necessary to be able to make additional research. Conclusion describes the effect of different geometries of mixing chamber to mixing. The aim of this work is to develop perfectly works mixing chamber, which will be manufactured and then implemented into experimental FGD reactor. The results will be validated by experiment after the mixing chamber will be manufactured.

  17. Characterization of a homemade ionization chamber for radiotherapy beams

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Lucio P., E-mail: lpneves@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Perini, Ana P., E-mail: aperini@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Santos, Gelson P. dos, E-mail: gpsantos@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Xavier, Marcos, E-mail: mxavier@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Khoury, Helen J., E-mail: khoury@ufpe.br [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, 50740-540 Recife (Brazil); Caldas, Linda V.E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil)

    2012-07-15

    A homemade cylindrical ionization chamber was studied for routine use in therapy beams of {sup 60}Co and X-rays. Several characterization tests were performed: leakage current, saturation, ion collection efficiency, polarity effect, stability, stabilization time, chamber orientation and energy dependence. All results obtained were within international recommendations. Therefore the homemade ionization chamber presents usefulness for routine dosimetric procedures in radiotherapy beams. - Highlights: Black-Right-Pointing-Pointer A homemade ionization chamber was studied for routine use in radiotherapy. Black-Right-Pointing-Pointer Several characterization tests were performed and the results were satisfactory. Black-Right-Pointing-Pointer This chamber was compared to commercial ones and the results were similar. Black-Right-Pointing-Pointer This chamber is suitable for calibration procedures in {sup 60}Co beams.

  18. Emulsion chamber observations and interpretation (HE 3)

    Science.gov (United States)

    Shibata, M.

    1986-01-01

    Experimental results from Emulsion Chamber (EC) experiments at mountain altitudes or at higher levels using flying carriers are examined. The physical interest in this field is concentrated on the strong interaction at the very high energy region exceeding the accelerator energy, also on the primary cosmic ray intensity and its chemical composition. Those experiments which observed cosmic ray secondaries gave information on high energy interaction characteristics through the analyses of secondary spectra, gamma-hadron families and C-jets (direct observation of the particle production occuring at the carbon target). Problems of scaling violation in fragmentation region, interaction cross section, transverse momentum of produced secondaries, and some peculiar features of exotic events are discussed.

  19. RETAINED STONE PIECE IN ANTERIOR CHAMBER

    Directory of Open Access Journals (Sweden)

    ZvornicaninJasmin, Nadarevic-VodencarevicAmra

    2015-04-01

    Full Text Available ABSTRACT We read with interest the article by Surekha et al. regarding the retained stone piece in anterior chamber. Similar to the results of previous studies, the authors found that delayed intraocular foreign body (IOFB management can result in good visual outcome without an apparent increased risk of endophthalmitis or other deleterious side effects. However, the authors failed to explain the exact reason for the diminution of vision in patients left eye. It is unclear what the uncorrected visual acuity was and what kind of correction was used, more precisely type and amount of cylinder, given the presence of the corneal opacity. Since the size of the IOFB is approximately 4x4x1mm, significant irido-corneal angle changes resulting in intraocular pressure raise and optic nerve head damage can be expected. Traumatic glaucoma following open globe injury can occur in 2.7 to 19% of cases, with several risk factors associated with glaucoma development (advanced age, poor visual acuity at presentation,perforating rather than penetrating ocular injury,lens injury, presence of vitreous hemorrhage and presence of an IOFB. Earlier reportsof latetraumaticoptic neuropathy onset, even after several years, indicate that this possibility cannot be completely ruled out too. Therefore, repeated intraocular pressure measurements, gonioscopy, pupillary reaction assessment, together with through posterior segment examination including visual field and optical coherence tomography examinations can be useful in determining the possible optic nerve damage as one of the possible reasons for visual acuity reduction. The authors did not suggest any operative treatment at this time. However, it should bear in mind that the inert anterior chamber IOFB could be a risk factor for non-infectious endophthalmitis development even after many years. Also, long term retained anterior chamber foreign body leads to permanent endothelial cell loss and can even result in a corneal

  20. Neutron sensitivity of thin gap chambers

    CERN Document Server

    Nanjo, H; Hasuko, K; Ishino, M; Kobayashi, T; Takemoto, T; Tsuno, S; Ye, B

    2005-01-01

    Thin gap chambers (TGC) will be used for triggering forward muons in the ATLAS detector for the LHC at CERN. A large amount of neutron background is foreseen in the ATLAS experiment. This paper describes the measurements of the neutron sensitivities (detection efficiencies) of the TGCs. The sensitivities of both small and real size TGCs to 2.5 and 14MeV mono-energetic neutrons were measured. For a small size TGC, sensitivities of 0.032% and 0.10% were measured to 2.5 and 14MeV neutrons, respectively, whereas for a real size TGC, sensitivities of 0.048% and 0.13% were measured. These measured values were in reasonably good agreement with the simulations based on the Geant4.

  1. Foreign Body Embedded in Anterior Chamber Angle

    Directory of Open Access Journals (Sweden)

    Shmuel Graffi

    2012-01-01

    Full Text Available Introduction. We present a case of a metallic foreign body embedded in the anterior chamber angle. After standing in close proximity to a construction worker breaking a tile, a 26-year-old woman using soft contact lens for the correction of mild myopia presented to emergency department for evaluation of a foreign body sensation of her right eye. Methods and Results. Diagnosis was confirmed by gonioscopic examination and a noncontrast CT scan of head and orbits. The foreign body was removed by an external approach without utilizing a magnet. The patient's final outcome was favorable. Discussion. The above is a rare clinical situation, which is impossible to detect on slit-lamp examination without a gonioscopic view. Proper imaging and a specific management are mandatory in order to achieve favorable outcome.

  2. The time projection chamber at triumf

    Science.gov (United States)

    Bryman, D.; Leitch, M.; Navon, I.; Numao, T.; Schlatter, P.; Dixit, M. S.; Hargrove, C. K.; Mes, H.; Bennett, A.; Macdonald, J. A.; Skegg, R.; Spuller, J.; Burnham, A.; Hasinoff, M.; Poutissou, J.-M.; Azuelos, G.; Depommier, P.; Martin, J.-P.; Poutissou, R.; Blecher, M.; Gotow, K.; Carter, A. L.

    1984-02-01

    The time projection chamber at TRIUMF is being used to search for muon-electron conversion. The best spatial resolution in the TPC, σ≂200 μm, occurs at the minimum drift length and for an optimum track-to-anode crossing angle determined by the magnetic field. The observed resolution is dependent on th diffusion of the drifting electrons, the track-to-anode crossing angle, E↘×B↘ effects near the anode wire and the discrete nature of the ionization process. Distortions due to positive ions leaking back into the drift volume from the anode wire region have been nearly eliminated by the use of a pulsed dual grid system.

  3. Acoustic analysis of a semi-anechoic chamber with intersection

    OpenAIRE

    P. Nassiri; M. R. Monazzam; F. Zivary Delavar

    2014-01-01

    Introduction: The previous studies have used fibrous absorbents usually in the form of cone-shaped wedges for making anechoic and semi-anechoic chambers which their design and construction have been costly and difficult. The present study aimed to design a semi-anechoic chamber, using rectangular fibrous absorbents and also perform acoustic analysis for it. . Material and Method: In the present study, which was done at semi-anechoic chamber of the laboratory in Tehran University of Medical...

  4. Ageing tests for the MEG II drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, M., E-mail: marco.venturini@pi.infn.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Baldini, A.M. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Baracchini, E. [ICEPP, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Cei, F.; D' Onofrio, A. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dussoni, S.; Galli, L.; Grassi, M. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Nicolò, D. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Signorelli, G.; Tenchini, F. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Zermini, A. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy)

    2016-07-11

    The MEG II drift chamber will track positrons from μ{sup +} decays in a very harsh environment. For testing the robustness of the chamber to ageing effects an irradiation facility was set up at INFN Pisa. - Highlights: • We built up an X-ray facility for ageing studies of particle detectors. • Stable irradiation conditions were obtained over one-month timescale. • A moderate gain loss is expected for the MEG II drift chamber.

  5. Central drift chamber for rare kaon decay spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.; Blackmore, E.W.; Bryman, D.A.; Cresswell, J.; Numao, T.

    1985-10-01

    Design of the central drift chamber for BNL experiment 787 and measurement of the decay K/sup +/ ..-->.. ..pi../sup +/ nu anti nu are discussed. A jet chamber type cell with 6 sense wires and no interspersed field wires has been designed to achieve good spatial resolution and efficiency in a 1 T magnetic field. Results of the testing of a prototype chamber are presented.

  6. NASA Teams With Army in Vortex Combustion Chamber Engine Test

    Science.gov (United States)

    2003-01-01

    This photograph depicts one of over thirty tests conducted on the Vortex Combustion Chamber Engine at Marshall Space Flight Center's (MSFC) test stand 115, a joint effort between NASA's MSFC and the U.S. Army AMCOM of Redstone Arsenal. The engine tests were conducted to evaluate an irnovative, 'self-cooled', vortex combustion chamber, which relies on tangentially injected propellants from the chamber wall producing centrifugal forces that keep the relatively cold liquid propellants near the wall.

  7. Double anterior chamber in a patient with glaucoma and microspherophakia

    Directory of Open Access Journals (Sweden)

    Hamid Khakshoor

    2011-01-01

    Full Text Available We report the case of a 16-year-old woman with microspherophakia and secondary open angle glaucoma. The patient presented with a membrane dividing the anterior chamber into two segments without edema or Descemet′s membrane detachment. Slit lamp biomicroscopy, Pentacam, and specular microscopy images were obtained. Double anterior chamber is primarily found in patients with anterior chamber anomalies when there is no history of surgery or trauma.

  8. Physiological responses to exposure to carbon dioxide and human bioeffluents

    DEFF Research Database (Denmark)

    Zhang, Xiaojing; Wargocki, Pawel; Lian, Zhiwei

    2015-01-01

    Present paper describes physiological responses as a result of exposures to CO2 (between 500 ppm to 3,000 ppm) with and without bioeffluents. Twenty-five subjects participated. They were exposed in the climate chamber for 255 minutes in groups of five at a time. During exposure, they performed...

  9. Heterogeneous Reactions of Polycyclic Aromatic Hydrocarbons on Atmospheric and Terrestrial Surfaces

    Science.gov (United States)

    Simonich, S. L.

    2014-12-01

    The heterogeneous reactions of five higher molecular weight polycyclic aromatic hydrocarbons (PAHs), benzo[a]pyrene-d12 (BaP-d12), benzo(k)fluoranthene-d12 (BkF-d12), benzo[g,h,i]perylene-d12 (BghiP-d12), dibenzo(a,i)pyrene-d14 (DBaiP-d14), and dibenzo[a,l]pyrene (DalP), with NO2, NO3/N2O5, O3, and OH radicals were investigated in a 7000 L indoor Teflon chamber. Quartz fiber filters (QFF) were used as the reaction surface and substrate and the analyses of parent PAHs and Nitro-PAH (NPAH) products was conducted using electron impact gas chromatographic mass spectrometry (GC/MS) and negative chemical ionization GC/MS. In parallel to the laboratory experiments, a theoretical study was conducted to assist in determining the formation of NPAH isomers based on the OH-radical initiated reaction. The thermodynamic stability of OH-PAH intermediates was used to indicate the position of highest electron density and the most stable NPAH products were synthesized to confirm their identity. NO2 and NO3/N2O5 were the most effective oxidizing agents in transforming PAHs deposited on filters to NPAHs, under the experimental conditions. Reaction of BaP-d12, BkF-d12 and BghiP-d12 resulted in the formation of several mono-nitro PAH isomer product, while the reaction of DalP and DaiP-d14 resulted in the formation of only one mono-nitro PAH isomer product. The direct-acting mutagenicity of the products increased the most after NO3/N2O5 exposure, particularly for BkF-d12 in which the formation of dinitro- PAHs was observed. In addition, the degradation of particulate matter (PM)-bound PAHs by heterogeneous reaction with OH radicals, O3, NO3/N2O5 was also studied. Ambient PM samples collected from Beijing, China and Riverside, California were exposed in an indoor chamber under simulated trans-Pacific atmospheric transport conditions and the formation of NPAHs was studied. NPAHs were most effectively formed during the NO3/N2O5 exposure and, for all exposures, there was no significant

  10. Radiation Target Area Sample Environmental Chamber (RTASEC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. proposes the Radiation Target Area Sample Environmental Chamber (RTASEC) as an innovative approach enabling radiobiologists to investigate the...

  11. Repair of isolated double-chambered right ventricle.

    Science.gov (United States)

    El Kouache, M; Babakhoya, A; Labib, S; El Madi, A; Atmani, S; Harandou, M; Abouabdilah, Y; Hida, M

    2013-01-01

    The finding of a double-chambered right ventricle (DCRV) is exceptionally rare as an isolated anomaly. It is a congenital cardiac anomaly in which the right ventricle is separated into two chambers, a proximal high-pressure chamber and a distal low-pressure chamber, by anomalous muscles or fibrous tissues in the right ventricular cavity. We report the case of a 6-year-old infant who was admitted for growth retardation. The patient was diagnosed with an isolated DCRV without any other associated congenital anomalies. The patient underwent a successful cardiac surgical procedure of enlargement repair; he was discharged in good clinical condition with a normal cardiac function.

  12. Repair of isolated double-chambered right ventricle

    OpenAIRE

    M El Kouache; A Babakhoya; S Labib; A El Madi; S Atmani; M Harandou; Y Abouabdilah; M Hida

    2013-01-01

    The finding of a double-chambered right ventricle (DCRV) is exceptionally rare as an isolated anomaly. It is a congenital cardiac anomaly in which the right ventricle is separated into two chambers, a proximal high-pressure chamber and a distal low-pressure chamber, by anomalous muscles or fibrous tissues in the right ventricular cavity. We report the case of a 6-year-old infant who was admitted for growth retardation. The patient was diagnosed with an isolated DCRV without any other associat...

  13. Propagation of the trip behavior in the VENUS vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Ohama, Taro; Yamada, Yoshikazu

    1995-03-01

    The high voltage system of the VENUS vertex chamber occasionally trips by a discharge somewhere among cathode electrodes during data taking. This trip behavior induces often additional trips at other electrodes such as the skin and the grid electrodes in the vertex chamber. This propagation mechanism of trips is so complicated in this system related with multi-electrodes. Although the vertex chamber is already installed inside the VENUS detector and consequently the discharge is not able to observe directly, a trial to estimate the propagation has been done using only the information which appears around the trip circuits and the power supply of the vertex chamber. (author).

  14. Atmosphere: Power, Critique, Politics

    DEFF Research Database (Denmark)

    Albertsen, Niels

    2016-01-01

    This paper hans three interrelated parts. First, atmosphere is approached through the concept of power. Atmospheres 'grip' us directly or mediate power indirectly by manipulating moods and evoking emotions. How does atmosphere relate to different conceptions of power? Second, atmospheric powers may...

  15. Development of a Spherical Combustion Chamber for Measuring Laminar Flame Speeds in Navy Bulk Fuels and Biofuel Blends

    Science.gov (United States)

    2011-12-01

    Atmospheres drf/dt Flame front history (mm/s) Du Mass diffusivity (mm 2 /s) in Inches K Flame stretch rate (s -1 ) KPa KiloPascals L...understanding of their physical, chemical and combustion kinetics are needed. It is well known that both the Octane number in homogenous charge, spark...chamber pressure during the gas fill process and the dynamic pressure history during combustion. The other transducer was used for measuring the

  16. Exposure Setup and Dosimetry for a Study on Effects of Mobile Communication Signals on Human Hematopoietic Stem Cells in vitro

    Directory of Open Access Journals (Sweden)

    M. Rohland

    2017-09-01

    Full Text Available In this paper we describe the design of an exposure setup used to study possible non-thermal effects due to the exposure of human hematopoietic stem cells to GSM, UMTS and LTE mobile communication signals. The experiments are performed under fully blinded conditions in a TEM waveguide located inside an incubator to achieve defined environmental conditions as required for the living cells. Chamber slides containing the cells in culture medium are placed on the septum of the waveguide. The environmental and exposure parameters such as signal power, temperatures, relative humidity and CO2 content of the surrounding atmosphere are monitored permanently during the exposure experiment. The power of the exposure signals required to achieve specific absorption rates of 0.5, 1, 2 and 4 W kg−1 are determined by numerical calculation of the field distribution inside the cell culture medium at 900 MHz (GSM, 1950 MHz (UMTS and 2535 MHz (LTE. The dosimetry is verified both with scattering parameter measurements on the waveguide with and without containers filled with cell culture medium and with temperature measurements with non-metallic probes in separate heating experiments.

  17. Exposure Setup and Dosimetry for a Study on Effects of Mobile Communication Signals on Human Hematopoietic Stem Cells in vitro

    Science.gov (United States)

    Rohland, Martina; Baaske, Kai; Gläser, Katharina; Hintzsche, Henning; Stopper, Helga; Kleine-Ostmann, Thomas; Schrader, Thorsten

    2017-09-01

    In this paper we describe the design of an exposure setup used to study possible non-thermal effects due to the exposure of human hematopoietic stem cells to GSM, UMTS and LTE mobile communication signals. The experiments are performed under fully blinded conditions in a TEM waveguide located inside an incubator to achieve defined environmental conditions as required for the living cells. Chamber slides containing the cells in culture medium are placed on the septum of the waveguide. The environmental and exposure parameters such as signal power, temperatures, relative humidity and CO2 content of the surrounding atmosphere are monitored permanently during the exposure experiment. The power of the exposure signals required to achieve specific absorption rates of 0.5, 1, 2 and 4 W kg-1 are determined by numerical calculation of the field distribution inside the cell culture medium at 900 MHz (GSM), 1950 MHz (UMTS) and 2535 MHz (LTE). The dosimetry is verified both with scattering parameter measurements on the waveguide with and without containers filled with cell culture medium and with temperature measurements with non-metallic probes in separate heating experiments.

  18. The Design and Construction of a Long-Distance Atmospheric Propagation Test Chamber

    Science.gov (United States)

    2015-06-01

    with the many opportunities that led to this one. Any and all of my successes are possible because they care for (and sometimes spoil) me. Thirdly...technical foundation to compete for said scholarship. From a teenager with low SAT scores and poor math and science records, this opportunity has been...material by burning or melting it [4]. For example, light aircraft skin consists of approximately 1 mm thick aluminum. To melt a ~100 cm2 hole in this

  19. Production of gamma rays with energies greater than 30 MeV in the atmosphere

    Science.gov (United States)

    Thompson, D.; Fichtel, C.; Kniffen, D.

    1974-01-01

    A three-dimensional study of atmospheric gamma rays with energy greater than 30 MeV has been carried out. Experimental results were obtained from four balloon flights from Palestine, Texas, with a 15 cm by 15 cm digitized wire grid spark chamber. The energy spectrum for downward-moving gamma rays steepens with increasing atmospheric depth. Near the top of the atmosphere, the spectrum steepens with increasing zenith angle. Experimental results compare reasonably well with a three-dimensional Monte Carlo calculation of atmospheric gamma ray production. Inclusion of upward-moving gamma rays makes possible the use of atmospheric secondaries for in-flight calibration of satellite gamma ray detectors.

  20. Combined effects of CO2 enrichment, changes in diurnal light level and water stress on foliar metabolites of potato plants grown in naturally sunlit controlled environment chambers

    Science.gov (United States)

    Potato plants (Solanum tuberosum L. cv Kennebec) were grown in outdoor, naturally sunlit, soil-plant-atmosphere research (SPAR) chambers. Drought treatments were imposed at post-tuber initiation stage to assess water stress effects on leaf metabolites, and interactions with enriched CO2 concentrati...