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Sample records for atmospheric exposure chambers

  1. Contamination of ionization chamber due to tritium exposure

    International Nuclear Information System (INIS)

    The contamination of three ionization chambers (Cu, Ni-plated, and Au-plated chambers) due to exposure to HT or HTO was measured. Considerable contamination took place for all of the chambers due to exposure to HTO. This is caused by the physical adsorption of HTO. The extent of the contamination differed from each other (Ni > Au > Cu), being considered due to difference in their surface roughness. In case of the exposure to HT, the Cu-chamber was contaminated in room air, whereas the Ni-chamber did in dry air atmosphere. This is considered due to the adsorption of HTO (being formed with catalytic exchange reaction between HT and H2O) on the Cuchamber and that of HT on the Ni-chamber. The Au-chamber was not contaminated with the exposure to HT. This is because neither the adsorption of HT nor the catalytic exchange reaction takes place on this surface

  2. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    OpenAIRE

    Hohaus, T.; Kuhn, U.; S. Andres; Kaminski, M.; Rohrer, F.; Tillmann, R.; A. Wahner; R. Wegener; Yu, Z.; Kiendler-Scharr, A.

    2015-01-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber ...

  3. SMOG CHAMBER VALIDATION USING LAGRANGIAN ATMOSPHERIC DATA

    Science.gov (United States)

    A method was developed for validating outdoor smog chamber experiments as a means of determining the relationships between oxidant concentrations and its precursors - hydrocarbons and nitrogen oxides. When chamber experiments were performed in a manner that simulated relevant met...

  4. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    T. Hohaus

    2015-11-01

    Full Text Available A new PLant chamber Unit for Simulation (PLUS for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOC can be studied in detail. In PLUS all important enviromental parameters (e.g. temperature, PAR, soil RH etc. are well-controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leafes of the plants is constructed such that gases are exposed to FEP Teflon film and other Teflon surfaces only to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 LED panels which have an emission strength up to 800 μmol m−2 s−1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOC through PLUS under different humidity conditions are explored. Typical plant characteristics such as light and temperature dependent BVOC emissions are studied using six Quercus Ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus Ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental set up and the utility of the newly added plant chamber.

  5. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    Science.gov (United States)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2015-11-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOC) can be studied in detail. In PLUS all important enviromental parameters (e.g. temperature, PAR, soil RH etc.) are well-controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leafes of the plants is constructed such that gases are exposed to FEP Teflon film and other Teflon surfaces only to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 LED panels which have an emission strength up to 800 μmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOC) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light and temperature dependent BVOC emissions are studied using six Quercus Ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus Ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental set up and the utility of the newly added plant chamber.

  6. A new plant chamber facility, PLUS, coupled to the atmosphere simulation chamber SAPHIR

    Science.gov (United States)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2016-03-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been built and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow-through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees is mixed with synthetic air and transferred to the SAPHIR chamber, where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOCs) can be studied in detail. In PLUS all important environmental parameters (e.g., temperature, photosynthetically active radiation (PAR), soil relative humidity (RH)) are well controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leaves of the plants is constructed such that gases are exposed to only fluorinated ethylene propylene (FEP) Teflon film and other Teflon surfaces to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 light-emitting diode (LED) panels, which have an emission strength up to 800 µmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOCs) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light- and temperature- dependent BVOC emissions are studied using six Quercus ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental setup and the utility of the newly added plant chamber.

  7. Vapor chambers for an atmospheric cloud physics laboratory

    Science.gov (United States)

    Fleischman, G. L.; Scollon, T. R., Jr.; Loose, J. D.

    1980-01-01

    The methanol/stainless steel vapor chambers (flat-plate heat pipes) discussed in this paper were developed for use in spaceborne atmospheric cloud chambers. This application imposed stringent thermal and mechanical requirements on the design. Flatness, low thermal mass, vibration, and structural integrity requirements were achieved in addition to precision temperature uniformity and thermal transport. Heat transfer coefficients on the order of 0.34 to 0.40 W/sq cm -C were measured. The vapor chambers are capable of transporting 170 W-cm per cm of width in either the axial or side-to-side direction.

  8. Prototype exposure chamber of radon for animal experiments

    International Nuclear Information System (INIS)

    To evaluate a dose conversion factor from the 'Working Level of Month' (WLM) of radon to the absorbed dose (mGy), the quality of radon and its progeny was assessed, and exposures controlled for each deposition region were planed as follows: 1) exposure of radon gas to the entire respiratory tract, 2) exposure of 'unattached' fractions to the upper respiratory tract, 3) exposure of 'attached' fractions onto ultrafine particles to the deep lung, 4) exposure of 'attached' fractions onto fine particles to the lower respiratory tract, 5) exposure of 'attached' fractions onto coarse particles to the upper respiratory tract. In this preliminary study, a prototype exposure system of radon and its progeny for small rodents was designed. A whole body exposure chamber with a volume of about 0.5 m3 was used, which it held 20 rats. The aging and mixing chamber separated by the exposure chamber had a volume of about 1 m3. As career aerosols of radon progeny, carnauba wax aerosols as solid particles, DOS aerosols as liquid particles and NaCl aerosols as hygroscopic particles were selected. These aerosols generated using a vaporization-condensation method and/or an electrical classification method were almost monodisperse with σg of <1.2. The monitoring data on biologically related gases showed an importance in the oxygen injection system and the carbon dioxide absorption system. (author)

  9. Design of viewing windows for controlled-atmosphere chambers

    International Nuclear Information System (INIS)

    A guide to the design of safe viewing windows is presented. Design criteria, the properties of materials, the problems of structural design in unreliable materials such as glass, the mathematics of reliability and redundance, and problems associated with testing windows are discussed, and formulas are presented for the design of windows. Criteria adopted at ORNL for controlled-atmosphere chambers are presented, a program for surveying and upgrading the safety of existing facilities is described, and the results of this program are reported

  10. Dosimetry, instrumentation and exposure chambers for dc magnetic field studies

    Energy Technology Data Exchange (ETDEWEB)

    Tenforde, T.S.

    1979-03-01

    The principal objective of this report is to describe in detail an exposure chamber that was developed at the Lawrence Berkeley Laboratory for automated, noninvasive studies of rodent physiology during exposure to high DC magnetic fields. A second objective is to discuss some of the unique instrumentation problems that must be overcome in order to record bioelectric signals from laboratory animals in the presence of a magnetic field. Finally, a description will be given of the various dosimetry techniques that can be employed for quantitation of magnetic field strength.

  11. Dosimetry, instrumentation and exposure chambers for dc magnetic field studies

    International Nuclear Information System (INIS)

    The principal objective of this report is to describe in detail an exposure chamber that was developed at the Lawrence Berkeley Laboratory for automated, noninvasive studies of rodent physiology during exposure to high DC magnetic fields. A second objective is to discuss some of the unique instrumentation problems that must be overcome in order to record bioelectric signals from laboratory animals in the presence of a magnetic field. Finally, a description will be given of the various dosimetry techniques that can be employed for quantitation of magnetic field strength

  12. Investigation of Monoterpene Degradation in the Atmospheric Simulation Chamber SAPHIR

    Science.gov (United States)

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

    2013-04-01

    Monoterpenes are the volatile organic compound (VOC) species with the highest emission rates on a global scale beside isoprene. In the atmosphere these compounds are rapidly oxidized. Due to their high reactivity towards hydroxyl radicals (OH) they determine the radical chemistry under biogenic conditions if monoterpene concentration is higher than isoprene concentration. Recent field campaigns showed large discrepancies between measured and modeled OH concentration at low NOx conditions together with high reactivity of VOC towards OH (Hofzumahaus et al. 2009) especially in tropical forest areas (Lelieveld et al. 2008). These discrepancies were partly explained by new reaction pathways in the isoprene degradation mechanism (Whalley et al 2011). However, even an additional recycling rate of 2.7 was insufficient to explain the measured OH concentration. So other VOC species could be involved in a nonclassical OH recycling. Since the discrepancies in OH also occurred in the morning hours when the OH chemistry was mainly dominated by monoterpenes, it was assumed that also the degradation of monoterpenes may lead to OH recycling in the absence of NO. (Whalley et al 2011). The photochemical degradation of four monoterpene species was studied under high VOC reactivity and low NOx conditions in a dedicated series of experiments in the atmospheric simulation chamber SAPHIR from August to September 2012 to overcome the lack of mechanistic information for monoterpene degradation schemes. α-Pinene, β-pinene and limonene were chosen as most prominent representatives of this substance class. Moreover the degradation of myrcene was investigated due to its structural analogy to isoprene. The SAPHIR chamber was equipped with instrumentation to measure all important OH precursors (O3, HONO, HCHO), the parent VOC and their main oxidation products, radicals (OH, HO2, RO2), the total OH reactivity, and photolysis frequencies to investigate the degradation mechanism of monoterpenes in

  13. Large organic aerosols in a human exposure chamber : Applications in occupational dermatology and lung medicine

    OpenAIRE

    Lundgren, Lennart

    2006-01-01

    Exposure to large organic aerosol particles may cause respiratory and skin reactions. The use of human exposure chambers offers possibilities for experimental exposure challenges carried out with patients, in research and for investigations of the effects of exposure on the skin and in the respiratory tract. The present aim was to study the performance of modern human whole-body exposure chambers during generation of large organic particles, and to develop and test new me...

  14. 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 &...

  15. Collection and measurement of atmospheric contaminants during Skylab AM/MDA unmanned altitude chamber test

    Science.gov (United States)

    1972-01-01

    The analytical data obtained from both cryogenic and grab sampling of the atmosphere of the Skylab AM/MDA during an 84 hour unmanned chamber run are reported. The level of contaminants found at different points of the test chamber are tabulated. The results indicate that there was no clear trend of increasing or decreasing contaminant levels during the test run.

  16. Development of exposure assessment method with the chamber

    Science.gov (United States)

    Kato, N.; Koyama, Y.; Yokoyama, H.; Matsui, Y.; Yoneda, M.

    2015-05-01

    This study aims at developing the measurement method of nanoparticle concentration and at getting a representative value of nanoparticle uniform concentration due to chamber ventilation. We conducted a chamber equipped with HEPA filter and control the background nanoparticles concentration by using an adequate ventilation. Then, we used generator to evaluate concentration in the chamber uniformity. We measured background value and source counts at the particle size distribution by SMPS. In addition, we performed numerical analysis with CFD model OpenFoam. As results, we found that there is no aggregate in experimental conditions in this study. Though we confirmed that it is difficult to uniformalise nanoparticle concentration, However we also found simulation results showed higher reproducibility. Therefore, we could assess nanoparticle size distribution and concentration in our chamber at this stage.

  17. Construction and Characterization of an Atmospheric Simulation Smog Chamber

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Currently, air pollution in Beijing has become a complex problem with two types of source pollutants:coal smoke and photochemical smog. Furthermore the maximum hourly mean concentration of O3 increases continuously, especially in the summer. In order to simulate the photochemical reaction, develop an air quality simulation model and further improve the air quality of Beijing, a precisely temperature-controlled,indoor, smog chamber facility was designed and constructed at Tsinghua University. Characterization experiments have been carried out to acquire the basic parameters of the smog chamber, such as the wall loss rates of NO2, NO, 03, C3H6 and particulate matter (PM), the intensity of ultraviolet (UV) light in the chamber, the reactivity of the purified air and the reproducibility of the experimental results. The results indicate that the facility performs up to specifications, and can meet the demands required for simulating the photochemical reaction. The effect of high primary contaminated PM on the formation of ozone and secondary organic aerosol (SOA) is under investigation.

  18. Design of an exposure chamber to test samplers used in the evaluation of personal exposure to nanoparticles

    Science.gov (United States)

    Amin, R.; Izadi, H.; Quémerais, B.

    2015-05-01

    The aim of this study was to design a laboratory size exposure chamber for the testing of samplers used to collect personal exposure samples for nanoparticles. A polyethylene cylindrical container with a diameter of 42 cm and height of 60 cm was used as the testing chamber. The chamber was divided into 2 parts by an aluminium honey comb. Particles generated using a 1 jet Collison nebulizer (BGI) operating at a flow rate of 4L/min were inserted into the chamber via a tube located near to the top of the chamber. A heater was inserted just after the nebulizer to avoid condensation of water in the tubing, and dilution air, running at 10L/min was inserted just after the heater. As particle charge can dramatically affect sampling a particle neutralizer was attached to the generation system so as to neutralize the particles before they enter the chamber. A diffusion dryer was used to remove any water from the air stream prior to enter the chamber. A fan was used to mix and distribute the generated particles. After generation and mixing, the particles passed through the aluminium honeycomb which is essential to eliminate any turbulent or unwanted air flow. Six sampling ports along with a pressure gauge were placed on the walls 15 cm from the bottom of the chamber. The pressure gauge was added to ensure the desired pressure is achieved during sampling. The sampling ports allowed for the connection of five samplers and sampling pumps as well as the connection of an ultrafine particle counter. The exposure chamber was developed to assess various samplers for carbon nanotubes and cellulose nanocrystals. Results showed that the chamber was working properly and that mixing was sufficiently uniform to test samplers.

  19. Centrifuge modeling of soil atmosphere interaction using climatic chamber

    OpenAIRE

    CAICEDO, B; TRISTANCHO, J; THOREL, Luc

    2010-01-01

    Soil-atmospheric interaction processes such as infiltration or evaporation can have a significant effect on the behavior of geotechnical structures located near the soil surface. This paper focuses on the drying process of soils due to evaporation. The scaling laws are analyzed and the results of the application of two cycles of heating and cooling on a soil mass are presented. Based on these results, conclusions about the feasibility of reproducing evaporation on centrifuge models are recomm...

  20. 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.

  1. Environmental Chamber Study of Atmospheric Chemistry and Secondary Organic Aerosol Formation Using Cavity Enhanced Absorption Spectroscopy

    OpenAIRE

    Liu, Yingdi

    2011-01-01

    Air pollution and global climate change are important environmental issues that affect our society. Deeper understanding of atmospheric chemistry is required to understand these problems and to develop effective control strategies. Environmental chambers have been used for the past few decades to study atmospheric chemistry and investigate processes leading to secondary pollutant formation. This thesis work provides two different high sensitivity real time cavity enhance absorption spectrosco...

  2. 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.

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    A. Wisthaler

    2007-11-01

    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 on-line 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 good.

  5. Influence of the combustion chamber design on the equivalence ratio of atmospheric gas burners

    International Nuclear Information System (INIS)

    A lot of residential gas appliances for heating and hot water supply are equipped with atmospheric burners. To ensure flame stability and constant favourable equivalence ratio of fully premixed gas burners for low pollutant emissions the response of air entrainment on combustion chamber design has to be taken into account. Optimization of geometrical parameters is often based on experience and time consuming experimental work. This report deals with results of a theoretical and experimental study performed on three common gas burners with and without combustion chamber and heat exchanger installed. The influence of combustion chamber geometry and cooling on burnt and unburnt gas temperature and consequently density gradients has been examined with thermal loads in the normal operation range. This leads to changes in the pressure field of the injector tubes as well as in the combustion chamber and hence equivalence ratio due to variation of pressure losses and mass flow. A significant decrease of the equivalence ratio has been obtained especially under lower thermal load operation with a sealed combustion chamber which could result in flash back or increased CO- emissions. The optimized geometry yields an almost constant equivalence ratio under design operating condition. The methods described and coherences obtained can help to lower expenditure of time on development. (author)

  6. State-of-the-art exposure chamber for highly controlled and reproducible THz biological effects studies

    Science.gov (United States)

    Cerna, Cesario Z.; Elam, David P.; Echchgadda, Ibtissam; Sloan, Mark A.; Wilmink, Gerald J.

    2014-03-01

    Terahertz (THz) imaging and sensing technologies are increasingly being used at international airports for security screening purposes and at major medical centers for cancer and burn diagnosis. The emergence of new THz applications has directly resulted in an increased interest regarding the biological effects associated with this frequency range. Knowledge of THz biological effects is also desired for the safe use of THz systems, identification of health hazards, and development of empirically-based safety standards. In this study, we developed a state-of-the-art exposure chamber that allowed for highly controlled and reproducible studies of THz biological effects. This innovative system incorporated an industry grade cell incubator system that permitted a highly controlled exposure environment, where temperatures could be maintained at 37 °C +/- 0.1 °C, carbon dioxide (CO2) levels at 5% +/- 0.1%, and relative humidity (RH) levels at 95% +/- 1%. To maximize the THz power transmitted to the cell culture region inside the humid incubator, a secondary custom micro-chamber was fabricated and incorporated into the system. This micro-chamber shields the THz beam from the incubator environment and could be nitrogen-purged to eliminate water absorption effects. Additionally, a microscope that allowed for real-time visualization of the live cells before, during, and after THz exposure was integrated into the exposure system.

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

    International Nuclear Information System (INIS)

    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

  8. 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

  9. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing

    Science.gov (United States)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerone C.; Kolody, Mark R.

    2011-01-01

    Evaluation of metal-based structures has long relied on atmospheric exposure test sites to determine corrosion resistance in marine environments. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions of the corrosive environment. Their success for correlation to atmospheric exposure is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated laboratory testing, which often focuses on the electrochemical reactions that occur during corrosion conditions, has yet to be universally accepted as a useful tool in predicting the long term service life of a metal despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard and their use is imperative, a method that correlates timescales from atmospheric exposure to accelerated testing would be very valuable. This work uses surface chemistry to interpret the chemical changes occurring on low carbon steel during atmospheric and accelerated corrosion conditions with the objective of finding a correlation between its accelerated and long-term corrosion performance. The current results of correlating data from marine atmospheric exposure conditions at the Kennedy Space Center beachside corrosion test site, alternating seawater spray, and immersion in typical electrochemical laboratory conditions, will be presented. Key words: atmospheric exposure, accelerated corrosion testing, alternating seawater spray, marine, correlation, seawater, carbon steel, long-term corrosion performance prediction, X-ray photoelectron spectroscopy.

  10. COMPASS - COMparative Particle formation in the Atmosphere using portable Simulation chamber Study techniques

    Science.gov (United States)

    Bonn, B.; Sun, S.; Haunold, W.; Sitals, R.; van Beesel, E.; dos Santos, L.; Nillius, B.; Jacobi, S.

    2013-12-01

    In this study we report the set-up of a novel twin chamber technique that uses the comparative method and establishes an appropriate connection of atmospheric and laboratory methods to broaden the tools for investigations. It is designed to study the impact of certain parameters and gases on ambient processes, such as particle formation online, and can be applied in a large variety of conditions. The characterisation of both chambers proved that both chambers operate identically, with a residence time xT (COMPASS1) = 26.5 ± 0.3 min and xT (COMPASS2) = 26.6 ± 0.4 min, at a typical flow rate of 15 L min-1 and a gas leak rate of (1.6 ± 0.8) × 10-5 s-1. Particle loss rates were found to be larger (due to the particles' stickiness to the chamber walls), with an extrapolated maximum of 1.8 × 10-3 s-1 at 1 nm, i.e. a hundredfold of the gas leak rate. This latter value is associated with sticky non-volatile gaseous compounds, too. Comparison measurement showed no significant differences. Therefore operation under atmospheric conditions is trustworthy. To indicate the applicability and the benefit of the system, a set of experiments was conducted under different conditions, i.e. urban and remote, enhanced ozone and terpenes as well as reduced sunlight. In order to do so, an ozone lamp was applied to enhance ozone in one of two chambers; the measurement chamber was protected from radiation by a first-aid cover and volatile organic compounds (VOCs) were added using a small additional flow and a temperature-controlled oven. During the elevated ozone period, ambient particle number and volume increased substantially at urban and remote conditions, but by a different intensity. Protection of solar radiation displayed a clear negative effect on particle number, while terpene addition did cause a distinct daily pattern. E.g. adding β pinene particle number concentration rose by 13% maximum at noontime, while no significant effect was observable during darkness. Therefore

  11. Oxidation of a new Biogenic VOC: Chamber Studies of the Atmospheric Chemistry of Methyl Chavicol

    Science.gov (United States)

    Bloss, William; Alam, Mohammed; Adbul Raheem, Modinah; Rickard, Andrew; Hamilton, Jacqui; Pereira, Kelly; Camredon, Marie; Munoz, Amalia; Vazquez, Monica; Vera, Teresa; Rodenas, Mila

    2013-04-01

    The oxidation of volatile organic compounds (VOCs) leads to formation of ozone and SOA, with consequences for air quality, health, crop yields, atmospheric chemistry and radiative transfer. Recent observations have identified Methyl Chavicol ("MC": Estragole; 1-allyl-4-methoxybenzene, C10H12O) as a major BVOC above pine forests in the USA, and oil palm plantations in Malaysian Borneo. Palm oil cultivation, and hence MC emissions, may be expected to increase with societal food and bio fuel demand. We present the results of a series of simulation chamber experiments to assess the atmospheric fate of MC. Experiments were performed in the EUPHORE facility, monitoring stable product species, radical intermediates, and aerosol production and composition. We determine rate constants for reaction of MC with OH and O3, and ozonolysis radical yields. Stable product measurements (FTIR, PTRMS, GC-SPME) are used to determine the yields of stable products formed from OH- and O3- initiated oxidation, and to develop an understanding of the initial stages of the MC degradation chemistry. A surrogate mechanism approach is used to simulate MC degradation within the MCM, evaluated in terms of ozone production measured in the chamber experiments, and applied to quantify the role of MC in the real atmosphere.

  12. Development of a sample chamber with humidity control for an atmospheric positron probe microanalyzer

    International Nuclear Information System (INIS)

    In order to perform positron lifetime measurements on thin films under atmospheric conditions, a slow positron microbeam was extracted into air using silicon nitride thin films (30 nm and 200 nm) as a vacuum window. Even the thinner window (30 nm) was found to reliably withstand a differential pressure of 1 atm under various stress tests. By placing the sample in an enclosed chamber through which gas with a fixed, controllable relative humidity (RH) was continuously passed, the RH dependence of the ortho-positronium lifetime for bulk fused silica was examined.

  13. 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.

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

    International Nuclear Information System (INIS)

    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

  15. Reduced adverse effects on Si thin film solar cells caused by growth chamber air exposure

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fan; Zhang, Lin; Zheng, Yi; Schimitt, Francimar; Tso, Alan; Li, Lipan; Tsuei, Lun; Yuan, Zheng; Shieh, Brian [Thin Film Solar Products Division, Applied Materials, Santa Clara, CA 95054 (United States)

    2010-06-15

    The cost of photovoltaic (PV) energy is reduced by increasing solar cell power conversion efficiency and decreasing manufacture cost. An effective way of lowering the cost of Si thin film solar cells (TFSC) is to grow panels on large-area substrates. In this paper we study the effect of air residual to Si TFSC grown on 5.7 m{sup 2} glass in plasma-enhanced chemical vapor deposition (PECVD) chambers. Structural and chemical analysis show that oxygen incorporated into the Si films behaved as impurity dopant in the hydrogenated microcrystalline Si ({mu}c-Si) layers and reduced the efficiency of amorphous Si (a-Si)/{mu}c-Si tandem junction solar cells when the film had oxygen concentration >2 x 10{sup 19} atoms/cm{sup 3}. Higher oxygen content further suppressed the {mu}c-Si crystallization. We found that hydrogen plasma treatment of process chamber before Si film deposition effectively reduced the adverse effects of air exposure and improved both film quality and solar cell performance. The hydrogen-treated chamber produced contamination-free, solar cells with consistent, initial efficiency >10%. (author)

  16. Chamber experiments to investigate the release of fungal IN into the atmosphere

    Science.gov (United States)

    Kunert, Anna Theresa; Krüger, Mira; Scheel, Jan Frederik; Helleis, Frank; Pöschl, Ulrich; Fröhlich-Nowoisky, Janine

    2015-04-01

    Biological aerosol particles are ubiquitous in the atmosphere. Several types of microorganisms like bacteria, fungi and lichen have been identified as sources of biological ice nuclei (IN). They are a potentially strong source of atmospheric IN, as some of them are able to catalyze ice formation at relatively warm subfreezing temperatures. Common plant-associated bacteria are the best-known biological IN but recently ice nucleation activity in a variety of fungal species such as Mortierella alpina, Isaria farinosa, Acremonium implicatum was found. These fungal species are widely spread throughout the world and are present in soil and air. Their IN seem to be proteins, which are not anchored in the fungal cell wall. To which extent these small, cell-free IN are emitted directly into the atmosphere remains unexplored just as other processes, which probably indirectly release fungal IN e.g. absorbed onto soil dust particles. To analyze the release of fungal IN into the air, we designed a chamber, whose main principle is based on the emission of particles into a closed gas compartment and the subsequent collection of these particles in water. The concentration of the collected IN in the water is determined by droplet freezing assays. For a proof of principles, fungal washing water containing cell-free IN was atomized by an aerosol generator and the produced gas stream was lead through a water trap filled with pure water. Preliminary results show a successful proof of principles. The chamber design is capable of collecting aerosolic IN produced by an aerosol generator with fungal washing water. In ongoing experiments, alive or dead fungal cultures are placed into the chamber and a gentle, particle free air stream is directed over the fungi surface. This gas stream is also lead through water to collect particles, which might be emitted either actively or passively by the fungi. Further experiments will be e.g. conducted under different relative humidities. Results

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

    Institute of Scientific and Technical Information of China (English)

    V. Catoire; F. Bernard; Y. MébarKi; A. Mellouki; G. Eyglunent; V. Da(e)le; C. Robert

    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 2909.71,2912.09and 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 2σ detection limit of 88 ppt in volume mixing ratio with a response time of 60 see 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.

  18. Characterization of a multiculture in-vitro cell exposure chamber for assessing the biological impact of diesel engine exhaust

    International Nuclear Information System (INIS)

    In order to study the various health influencing parameters related to particulate as well as to gas-phase pollutants emitted by Diesel engine exhaust, there is an urgent need for appropriate sampling devices and methods for cell exposure studies and associated biological and toxicological tests. In a previous paper [1], a specific concept for a cell culture exposure chamber was introduced to allow the uniform exposure of cell cultures to diesel aerosols. In the present work, this cell culture exposure chamber is evaluated and characterized with state-of-the-art nanoparticles measurement instrumentation to assess the local deposition of soot aggregates on the cell cultures and any losses due to particle deposition on the cell culture exposure chamber walls, and in addition an upgraded Multiculture Exposure Chamber (MEC) for in vitro continuous flow cell exposure tests is introduced with improved, compared to the previous version, features. Analysis and design of the MEC employs CFD and true to geometry representations of soot particle aggregates.

  19. Copper patinas formed in different atmospheres and exposure times

    International Nuclear Information System (INIS)

    Atmospheric corrosion products in copper samples, known as patinas, formed in industrial-marine, severe-marine and rural atmospheres exposed for 1,2,3, and 4 years, have been studied. The nature and structure of the products formed, characterized by X-ray diffraction (XRD) and infrared spectrometry (FTIR) depend on the time of exposure and the type of atmosphere. Copper patinas have been extensively mentioned in the literature, but the structural nature of their compounds, which vary according to the time of exposure and types of atmospheres, is still not adequately described in the literature. In order to give a contribution to this area, copper panels were exposed for 1,2,3, and 4 years in different types of atmospheres representing situations commonly observed, and subsequently the patinas were studied by XRD and FTIR 150 mm x 1 mm copper panels from commercial copper were exposed to three different atmospheric conditions in Portugal: industrial-marine (Leixoes, near Oporto, highly industrialized city close to the Ocean, subject to SO2 from refineries); rural (Pego, small village in rural environment). The panels, attached to the appropriate stands, in accordance with ISO 8565 (1), were exposed for periods of 1,2,3 and 4 years, adequately collected for laboratory analysis by infrared spectrometry (FTIR). (Author)

  20. Comparison of secondary organic aerosol formed with an aerosol flow reactor and environmental reaction chambers: effect of oxidant concentration, exposure time and seed particles on chemical composition and yield

    Directory of Open Access Journals (Sweden)

    A. T. Lambe

    2014-12-01

    Full Text Available We performed a systematic intercomparison study of the chemistry and yields of SOA generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0×108 to 2.2×1010 molec cm−3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2×106 to 2×107 molec cm−3 over exposure times of several hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. A linear correlation analysis of the mass spectra (m=0.91–0.92, r2=0.93–0.94 and carbon oxidation state (m=1.1, r2=0.58 of SOA produced in the flow reactor and environmental chambers for OH exposures of approximately 1011 molec cm−3 s suggests that the composition of SOA produced in the flow reactor and chambers is the same within experimental accuracy as measured with an aerosol mass spectrometer. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors, rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed

  1. Comparison of OH reactivity instruments in the atmosphere simulation chamber SAPHIR

    Science.gov (United States)

    Fuchs, Hendrik

    2016-04-01

    OH reactivity measurement has become an important measurement to constrain the total OH loss frequency in field experiments. Different techniques have been developed by various groups. They can be based on flow-tube or pump and probe techniques, which include direct OH detection by fluorescence, or on a comparative method, in which the OH loss of a reference species competes with the OH loss of trace gases in the sampled air. In order to ensure that these techniques deliver equivalent results, a comparison exercise was performed under controlled conditions. Nine OH reactivity instruments measured together in the atmosphere simulation chamber SAPHIR (volume 270 m3) during ten daylong experiments in October 2015 at ambient temperature (5 to 10° C) and pressure (990-1010 hPa). The chemical complexity of air mixtures in these experiments varied from CO in pure synthetic air to emissions from real plants and VOC/NOx mixtures representative of urban atmospheres. Potential differences between measurements were systematically investigated by changing the amount of reactants (including isoprene, monoterpenes and sesquiterpenes), water vapour, and nitrogen oxides. Some of the experiments also included the oxidation of reactants with ozone or hydroxyl radicals, in order to elaborate, if the presence of oxidation products leads to systematic differences between measurements of different instruments. Here we present first results of this comparison exercise.

  2. Cleaning and air conditioning device for atmosphere in thermonuclear reactor chamber

    International Nuclear Information System (INIS)

    The device of the present invention removes tritium efficiently and attains ventilation and conditioning of a great amount of air flow. That is, there are disposed a humidity separator, a filter, a heater, a catalyst filled layer, a water jetting type humidifying heat insulation cooler and a cooler in this order from an inlet side (upstream) of contaminated room atmospheric gases. The catalyst filled layer, etc. are incorporated integrally into the ventilation air conditioning facility for ventilating air in the chamber of the thermonuclear reactor, to clean a tritium atmosphere at the same time. Accordingly, the device is made compact as a whole. A limit for the air flow rate owing to the use of the conventional catalyst tower and adsorbing tower is eliminated. Then a ventilating air conditioning for a great flow rate can be attained. Tritium is removed by cooling and dehumidification without using any adsorbent. Accordingly, an adsorbing tower is no more necessary and conventional regeneration operation is not required. As a result, space for installation is reduced, the system is simplified and the cost for construction and facility can be reduced. (I.S.)

  3. OH regeneration from methacrolein oxidation investigated in the atmosphere simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    H. Fuchs

    2014-02-01

    Full Text Available Hydroxyl radicals (OH are the most important reagent for the oxidation of trace gases in the atmosphere. OH concentrations measured during recent field campaigns in isoprene rich environments were unexpectedly large. A number of studies showed that unimolecular reactions of organic peroxy radicals (RO2 formed in the initial reaction step of isoprene with OH play an important role for the OH budget in the atmosphere at low mixing ratios of nitrogen monoxide (NO of less than 100 pptv. It has also been suggested that similar reactions potentially play an important role for RO2 from other compounds. Here, we investigate the oxidation of methacrolein (MACR, one major oxidation product of isoprene, by OH in experiments in the simulation chamber SAPHIR under controlled atmospheric conditions. The experiments show that measured OH concentrations are approximately 50% larger than calculated by current chemical models for conditions of the experiments (NO mixing ratio of 90 pptv. The analysis of the OH budget reveals a so far unaccounted OH source, which is correlated with the production rate of RO2 radicals from MACR. In order to balance the measured OH destruction rate, (0.77±0.3 OH radicals need to be additionally reformed from each OH that has reacted with MACR. The strong correlation of the missing OH source with the production of RO2 radicals is consistent with the concept of OH formation from unimolecular isomerization and decomposition reactions of RO2. The comparison of observations with model calculations gives a lower limit of 0.03 s−1 for the reaction rate constant, if the OH source is attributed to an isomerization reaction of one RO2 species formed in the MACR+OH reaction as suggested in literature. This fast isomerization reaction would be competitive to the reaction of this RO2 species with minimum 150 pptv NO.

  4. Model-aided radiometric determination of photolysis frequencies in a sunlit atmosphere simulation chamber

    Directory of Open Access Journals (Sweden)

    B. Bohn

    2004-10-01

    Full Text Available In this work diurnal and seasonal variations of mean photolysis frequencies for the atmosphere simulation chamber SAPHIR at Forschungszentrum Jülich are calculated. SAPHIR has a complex construction with UV permeable teflon walls allowing natural sunlight to enter the reactor volume. The calculations are based on external measurements of solar spectral actinic flux and a model considering the time-dependent impact of shadows from construction elements as well as the influence of the teflon walls. Overcast and clear-sky conditions are treated in a consistent way and different assumptions concerning diffuse sky radiance distributions are tested. Radiometric measurements inside the chamber are used for an inspection of model predictions. Under overcast conditions we obtain 74% and 67% of external values for photolysis frequencies j(NO2 (NO2+hν→NO+O(3P and j(O1D (O3+hν→O2+O(1D, respectively. On a clear sky summer day these values are time-dependent within ranges 0.65–0.86 and 0.60–0.73, for j(NO2 and j(O1D, respectively. A succeeding paper (Bohn et al., 2004 is dealing with an on-road test of the model approach by comparison with photolysis frequencies from chemical actinometry experiments within SAPHIR.

  5. Long-term ozone exposure and ozone uptake of grapevines in open-top chambers

    Science.gov (United States)

    Soja, G.; Reichenauer, T. G.; Eid, M.; Soja, A.-M.; Schaber, R.; Gangl, H.

    Ozone uptake of pot-grown grapevines, fruit yield and sugar concentrations in juice were studied over the course of 4 years. In three of the study years, plants were exposed to contrasting ozone levels in open-top chambers. Results showed that juice quality was more sensitive to ozone exposure than grape yield. Ozone-induced reductions in grape yield were best described by the level of ozone exposure in the 2 years prior to harvest, whereas sugar content of juice was mainly affected by current and previous year ozone exposure. Regression models were developed to facilitate quantitative assessments of the effects of ozone on yield and quality. The observed effects on grape yield and on carbohydrate accumulation in fruit were slightly better explained when a threshold of 6 nmol m -2 s -1 was applied to cumulative uptake of ozone (CUO6) compared with AOT40 exposure or other CUO thresholds. Curvilinear regression models were developed which explained up to 75% of variance of the datasets. These models indicate a critical level of 1.1 mmol m -2 ozone (CUO6 from June to September) to protect carbohydrate accumulation in fruit with ozone taken up by the plants over consecutive years. For grape yield the CUO6 threshold was 2.2 mmol m -2 ozone. Exceedance of this threshold would be expected to reduce grape yield and sugar translocation to fruit by 10% with substantial degree of uncertainty (95% confidence interval 1-19%). For individual years, the critical level could be increased to 2.3 mmol m -2 for carbohydrate accumulation and 3.5 mmol m -2 CUO6 for grape yield if the CUO6 of 0 in the subsequent year was not exceeded.

  6. Atmospheric interactions detected in both the upper and the lower chambers at Chacaltaya

    International Nuclear Information System (INIS)

    The cosmic ray interactions in the energy region 10 to the 13th power to 10 to the 17th power eV were studied by emulsion chambers exposed at Chacaltaya, 5220 m above sealevel. The chambers have a two-storied structure, and the events observed in both chambers give important informations on these phenomena. The first Centauro event was detected as a small shower at the bottom of the upper chamber and as a big fraction of energy deposit in the lower chamber, which indicates a high contribution of hadronic showers. Results of the events with continuation in the rather low energy region are described

  7. Atmospheric interactions detected in both the upper and the lower chambers at Chacaltaya

    Science.gov (United States)

    Amato, N. M.; Arata, N.; Maldonado, R. H. C.

    1985-01-01

    The cosmic ray interactions in the energy region 10 to the 13th power to 10 to the 17th power eV were studied by emulsion chambers exposed at Chacaltaya, 5220 m above sea-level. The chambers have a two-storied structure, and the events observed in both chambers give important informations on these phenomena. The first Centauro event was detected as a small shower at the bottom of the upper chamber and as a big fraction of energy deposit in the lower chamber, which indicates a high contribution of hadronic showers. Results of the events with continuation in the rather low energy region are described.

  8. The ASIBIA sea-ice facility: First results from the Atmosphere-Sea-Ice-Biogeochemistry in the Arctic chamber

    Science.gov (United States)

    France, James L.; Thomas, Max

    2016-04-01

    Working in the natural ocean-ice-atmosphere system is very difficult, as conducting fieldwork on sea-ice presents many challenges ice including costs, safety, experimental controls and access. The new ASIBIA (Atmosphere-Sea-Ice-Biogeochemistry in the Arctic) coupled Ocean-Sea-Ice-(Snow)-Atmosphere chamber facility at the University of East Anglia, UK, we are aiming to perform controlled first-year sea-ice investigations in areas such as sea-ice physics, physicochemical and biogeochemical processes in sea-ice and quantification of the bi-directional flux of gases in various states of first-year sea-ice conditions. The facility is a medium sized chamber with programmable temperatures from -55°C to +30°C, allowing a full range of first year sea-ice growing conditions in both the Arctic and Antarctic to be simulated. The water depth can be up to 1 m (including up to 25 cm of sea-ice) and an optional 1 m tall Teflon film atmosphere on top of the sea-ice, thus creating a closed and coupled ocean-sea-ice-atmosphere mesocosm. Ice growth in the tank is well suited for studying first-year sea-ice physical properties, with in-situ ice-profile measurements of temperature, salinity, conductivity, pressure and spectral light transmission. Underwater and above ice cameras are installed to record the physical development of the sea-ice. Here, we present the data from the first suites of experiments in the ASIBIA chamber focussing on sea-ice physics and give a brief description of the capabilities of the facility going forward. The ASIBIA chamber was funded as part of an ERC consolidator grant to the late Prof. Roland von Glasow and we hope this work and further development of the facility will act as a lasting legacy.

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

    Directory of Open Access Journals (Sweden)

    J. Thieser

    2013-01-01

    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 is 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 (25th/75th percentiles: 0.949/0.994; min/max: 0.540/0.999. The linear regression analysis of the campaign data set yielded very small intercepts (1.2 ± 5.3 pptv and the average slope of the regression lines was close to unity (1.02, min: 0.72, max: 1.36. The deviation of individual regression slopes from unity was always within the combined accuracies of each instrument pair. The very good correspondence between the NO3 measurements

  10. 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

  11. Modeling of atmospheric corrosion of metals and its acceleration by increasing temperature in chambers of artificial climate

    International Nuclear Information System (INIS)

    Data are given on studying the effect of temperature on the rates of iron, zinc, cadmium, and copper corrosion in a pure humid atmosphere and in the presence of a thin phase water layer on the metal. The coefficients of corrosion acceleration with temperature have been determined. By conducting the experiments in chambers with artificial climate at 40-60 deg C, it has been shown how the corrosion process can be accelerated on the metals investigated in comparison with real conditions

  12. Modelling the contribution of biogenic volatile organic compounds to new particle formation in the Jülich plant atmosphere chamber

    Science.gov (United States)

    Roldin, P.; Liao, L.; Mogensen, D.; Dal Maso, M.; Rusanen, A.; Kerminen, V.-M.; Mentel, T. F.; Wildt, J.; Kleist, E.; Kiendler-Scharr, A.; Tillmann, R.; Ehn, M.; Kulmala, M.; Boy, M.

    2015-09-01

    We used the Aerosol Dynamics gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM) to simulate the contribution of BVOC plant emissions to the observed new particle formation during photooxidation experiments performed in the Jülich Plant-Atmosphere Chamber and to evaluate how well smog chamber experiments can mimic the atmospheric conditions during new particle formation events. ADCHAM couples the detailed gas-phase chemistry from Master Chemical Mechanism with a novel aerosol dynamics and particle phase chemistry module. Our model simulations reveal that the observed particle growth may have either been controlled by the formation rate of semi- and low-volatility organic compounds in the gas phase or by acid catalysed heterogeneous reactions between semi-volatility organic compounds in the particle surface layer (e.g. peroxyhemiacetal dimer formation). The contribution of extremely low-volatility organic gas-phase compounds to the particle formation and growth was suppressed because of their rapid and irreversible wall losses, which decreased their contribution to the nano-CN formation and growth compared to the atmospheric situation. The best agreement between the modelled and measured total particle number concentration (R2 > 0.95) was achieved if the nano-CN was formed by kinetic nucleation involving both sulphuric acid and organic compounds formed from OH oxidation of BVOCs.

  13. A kinetic study of the reaction of ozone with ethylene in a smog chamber under atmospheric conditions

    Institute of Scientific and Technical Information of China (English)

    XU Yongfu; JIA Long; GE Maofa; DU Lin; WANG Gengchen; WANG Dianxun

    2006-01-01

    Ozone is one of the key species in the processes of atmospheric chemistry, which can be taken as an indicator of oxidation capacity in the troposphere, The reaction of ozone with reactive gases is an important process in the troposphere. Experimental simulation equipment of smog chamber for atmospheric reactions is used to study the reaction of ozone with ethylene in real atmospheric environment with ozone concentrations of 100-200 ppb. The concentrations of ozone and ethylene were monitored during the reaction with the combination of Model 49C-O3 Analyzer and GC-FID. A rate constant of 1.01×10-18 (cm3.mol-1.s-1) was obtained at 286.5 K,under condition of which the half-life of ozone was 88 min. The results obtained from our experiments are in excellent agreement with those reported previously by other researchers under extremely Iow pressure in terms of matrix-isolation technology. This demonstrates that our equipment of smog chamber for atmospheric reactions is reliable, which can be used for further research of the processes of atmospheric reactions.

  14. 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

  15. 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

    2011-01-01

    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 J O1D 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 clouds by fast

  16. Growth chamber for the cultivation of woody plants in a radioactive carbon dioxide atmosphere

    International Nuclear Information System (INIS)

    A growth chamber is described, suited for the production of uniformly C14-labelled plant material. Temperature and humidity is automatically controlled. Radioactive 14CO2 is supplied by means of a manually operated bariumcarbonate-reactor. The cultivation of poplars (Populus tremula), larches (Larix Europea) and Scots pines (Pinus silvestris) as well as their growth experiences are described. Average specific activity of the plant material was 2 μCi/gC. This growth chamber is especially useful for labelling woody plants over long growing periods. (orig.)

  17. 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.

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

    OpenAIRE

    G. Villena; I. Bejan; R. Kurtenbach; P. Wiesen; Kleffmann, J.

    2012-01-01

    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 comm...

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

    OpenAIRE

    Eva Mateo-Marti

    2014-01-01

    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 p...

  20. Modelling Contribution of Biogenic VOCs to New Particle Formation in the Jülich Plant Atmosphere Chamber

    Science.gov (United States)

    Liao, L.; Boy, M.; Mogensen, D.; Mentel, T. F.; Kleist, E.; Kiendler-Scharr, A.; Tillman, R.; Kulmala, M. T.; Dal Maso, M.

    2012-12-01

    Biogenic VOCs are substantially emitted from vegetation to atmosphere. The oxidation of BVOCs by OH, O3, and NO3 in air generating less volatile compounds may lead to the formation and growth of secondary organic aerosol, and thus presents a link to the vegetation, aerosol, and climate interaction system (Kulmala et al, 2004). Studies including field observations, laboratory experiments and modelling have improved our understanding on the connection between BVOCs and new particle formation mechanism in some extent (see e.g. Tunved et al., 2006; Mentel et al., 2009). Nevertheless, the exact formation process still remains uncertain, especially from the perspective of BVOC contributions. The purpose of this work is using the MALTE aerosol dynamics and air chemistry box model to investigate aerosol formation from reactions of direct tree emitted VOCs in the presence of ozone, UV light and artificial solar light in an atmospheric simulation chamber. This model employs up to date air chemical reactions, especially the VOC chemistry, which may potentially allow us to estimate the contribution of BVOCs to secondary aerosol formation, and further to quantify the influence of terpenes to the formation rate of new particles. Experiments were conducted in the plant chamber facility at Forschungszentrum Jülich, Germany (Jülich Plant Aerosol Atmosphere Chamber, JPAC). The detail regarding to the chamber facility has been written elsewhere (Mentel et al., 2009). During the experiments, sulphuric acid was measured by CIMS. VOC mixing ratios were measured by two GC-MS systems and PTR-MS. An Airmodus Particle size magnifier coupled with a TSI CPC and a PH-CPC were used to count the total particle number concentrations with a detection limit close to the expected size of formation of fresh nanoCN. A SMPS measured the particle size distribution. Several other parameters including ozone, CO2, NO, Temperature, RH, and flow rates were also measured. MALTE is a modular model to predict

  1. Development of a dose-controlled multiculture cell exposure chamber for efficient delivery of airborne and engineered nanoparticles

    International Nuclear Information System (INIS)

    In order to study the various health influencing parameters related to engineered nanoparticles as well as to soot emitted by Diesel engines, there is an urgent need for appropriate sampling devices and methods for cell exposure studies that simulate the respiratory system and facilitate associated biological and toxicological tests. The objective of the present work was the further advancement of a Multiculture Exposure Chamber (MEC) into a dose-controlled system for efficient delivery of nanoparticles to cells. It was validated with various types of nanoparticles (Diesel engine soot aggregates, engineered nanoparticles for various applications) and with state-of-the-art nanoparticle measurement instrumentation to assess the local deposition of nanoparticles on the cell cultures. The dose of nanoparticles to which cell cultures are being exposed was evaluated in the normal operation of the in vitro cell culture exposure chamber based on measurements of the size specific nanoparticle collection efficiency of a cell free device. The average efficiency in delivering nanoparticles in the MEC was approximately 82%. The nanoparticle deposition was demonstrated by Transmission Electron Microscopy (TEM). Analysis and design of the MEC employs Computational Fluid Dynamics (CFD) and true to geometry representations of nanoparticles with the aim to assess the uniformity of nanoparticle deposition among the culture wells. Final testing of the dose-controlled cell exposure system was performed by exposing A549 lung cell cultures to fluorescently labeled nanoparticles. Delivery of aerosolized nanoparticles was demonstrated by visualization of the nanoparticle fluorescence in the cell cultures following exposure. Also monitored was the potential of the aerosolized nanoparticles to generate reactive oxygen species (ROS) (e.g. free radicals and peroxides generation), thus expressing the oxidative stress of the cells which can cause extensive cellular damage or damage on DNA.

  2. OH regeneration from methacrolein oxidation investigated in the atmosphere simulation chamber SAPHIR

    OpenAIRE

    Fuchs, H; I.-H. Acir; Bohn, B.; Brauers, T.; H.-P. Dorn; R. Häseler; Hofzumahaus, A.; Holland, F.; Kaminski, M.; Li, X.; Lu, K.; A. Lutz; Nehr, S.; Rohrer, F.; Tillmann, R.

    2014-01-01

    Hydroxyl radicals (OH) are the most important reagent for the oxidation of trace gases in the atmosphere. OH concentrations measured during recent field campaigns in isoprene rich environments were unexpectedly large. A number of studies showed that unimolecular reactions of organic peroxy radicals (RO2) formed in the initial reaction step of isoprene with OH play an important role for the OH budget in the atmosphere at low mixing ratios of nitrogen monoxide...

  3. Rapid determination of atmospheric alpha contamination by using the Frisch grid ionization chamber

    International Nuclear Information System (INIS)

    In a radiation emergency situation, the majority of radionuclides is dispersed in the form of aerosols and can be captured on aerosol filters. Alpha-spectrometric analysis is necessary for alpha radionuclides emitting no gamma radiation. A Frisch grid ionization chamber has been tested for this purpose. Three types of filters were tested: Millipore membrane filters, Synpor membrane filters, and glass-fiber Whatman filters. Aerosols from the radon chamber were deposited on the filter by means of an aerosol sampler, the alpha-spectrum was measured and its quality was evaluated. For the next tests, the glass-fiber Whatman filter was chosen. The aim of the experiments that followed was to determine the limits of detection (LDs) for some radionuclides. Outdoor air samples were prepared using filters 10 cm in diameter. The interval between the end of sampling and the start of counting was different for each sample, owing to which the time dependence of the LD levels. The average LD shortly after sampling was about 1.1 Bq/filter and decreased to about 0.5 Bq/filter in 3 hours. (orig.)

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

    Directory of Open Access Journals (Sweden)

    R. M. Varma

    2009-10-01

    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. Analytic 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 (IBBCEAS, and laser-induced fluorescence (LIF. All broadband absorption spectrometers were optimized for the detection of the main target species of the campaign, NO2, 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.

  5. 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.

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

    OpenAIRE

    Dorn, H.-P.; Apodaca, R. L.; Ball, S. M.; Brauers, T.; S. S. Brown; Crowley, J. N.; Dubé, W. P.; H. Fuchs; R. Häseler; U. Heitmann; Jones, R L; Kiendler-Scharr, A.; I. Labazan; Langridge, J. M.; J. Meinen

    2013-01-01

    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) is 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...

  7. The reactive oxidant potential of different types of aged atmospheric particles: An outdoor chamber study

    Science.gov (United States)

    Rattanavaraha, Weruka; Rosen, Eli; Zhang, Haofei; Li, Qianfeng; Pantong, Karun; Kamens, Richard M.

    2011-07-01

    The reactive oxygen species (ROS) potential of aged diesel exhaust particulate matter (PM) and other aged aerosol systems in the presence and absence of an urban hydrocarbon environment was assessed. Experiments were performed in a 274 m 3 dual outdoor Teflon film chamber. Filter samples were taken to assess the oxidant generation associated with PM by an optimized dithiothreitol (DTT) method. Diesel exhaust PM had a higher ROS response when it was in the presence of an urban hydrocarbon mixture and was associated with significant O 3 production. For all the aged dilute diesel systems, ROS expression increased by a factor of 2-4 over fresh diesel particles. Other particle systems were also investigated. A low ROS was observed in most of the nighttime experiments, including the nighttime aerosols from SO 2 with O 3 and SO 2 aged by itself. However, when all the systems were compared, aged diesel exhaust tended to express very high ROS potentials, with secondary organic aerosols from an α-pinene + toluene + an urban HC mixture giving the highest ROS response.

  8. Establishment of Airborne Nanoparticle Exposure Chamber System to Assess Nano TiO2 Induced Mice Lung Effects

    Science.gov (United States)

    Chen, Chia-Hua; Li, Jui-Ping; Huang, Nai-Chun; Yang, Chung-Shi; Chen, Jen-Kun

    2011-12-01

    A great many governments have schemed their top priority to support the research and development of emerging nanotechnology, which lead to increasing products containing nanomaterials. However, platforms and protocols to evaluate the safety of nanomaterials are not yet established. We therefore design and fabricate a nanoparticle exposure chamber system (NECS) and try to standardize protocols to assess potential health risk of inhalable nanoparticles. This platform comprises: (1) nano-aerosol generators to produce homogeneous airborne nanoparticles, (2) double isolated container to prevent from unexpected exposure to humans, (3) gas supply system for housing animals or incubating cultured cells, and (4) system for automatic control and airborne nanoparticle analysis. The NECS providing multiple functions includes: (1) a secure environment to handle nanomaterials, (2) real-time measurement for the size and distribution of airborne nanoparticles, (3) SOP of safety evaluation for nanomaterials, and (4) key technology for the development of inhalable pharmaceuticals. We used NECS to mimic occupational environment for exploring potential adverse effects of TiO2 nanoparticles. The adult male ICR mice were exposed to 25nm, well-characterized TiO2 particles for 1 and 4 weeks. More than 90% of the inhaled TiO2 nanoparticles deposit in lung tissue, which tends to be captured by alveolar macrophages. Pulmonary function test does not show significant physiological changes between one and 4 weeks exposure. For plasma biochemistry analysis, there are no obvious inflammation responses after exposure for one and 4 weeks; however, disruption of alveolar septa and increased thickness of alveolar epithelial cells were observed. According to our results, the NECS together with our protocols show comprehensive integration and ideally fit the standard of OECD guildelines-TG403, TG412, TG413; it can be further customized to fulfill diverse demands of industry, government, and third party

  9. Experimental study of limestone and sandstone sulphation in polluted realistic conditions: the Lausanne Atmospheric Simulation Chamber (LASC)

    Energy Technology Data Exchange (ETDEWEB)

    Ausset, P.; Crovisier, J.L.; Delmonte, M.; Furlan, V.; Girardet, F.; Hammecker, C.; Jeannette, D.; Lefevre, R.A. [University of Paris 12, Creteil (France)

    1996-09-01

    The Lausanne Atmospheric Simulation Chamber (LASC) has been constructed with the aim of studying the SO{sub 2} effects on different materials. The behaviour of two carbonic stone types (limestone and sandstone), either clean or covered with fly ash or soot particles, were exposed at the following conditions, SO{sub 2} = 125 ppb (340 mg)gm({sup -3}), NO{sub 2} = 50 ppb (98){mu}g m{sup -3}, relative humidity = 79%, and temperature = 13{degree}C. This experiment was carried out over a 1 yr period. SO{sub 2} deposition velocity decreased with time and in different ways for each of the two stone types, clean or covered with fly ash or soot particles. During the first four months, the deposition velocity was higher on clean stones; later on, it was higher on the stone samples covered with fly ash. Throughout the experiment the SO{sub 2} deposition velocity on stone samples covered with soot particles was lower than on the clean samples and those covered by fly ash. Finally, the values of SO{sub 2} deposition velocity were confirmed by the chemical analysis of sulphur in the samples. Sulphur was present from the stone surface down to about 0.8 mm depth.

  10. Detection of Amines and Ammonia with an Ambient Pressure Mass Spectrometer using a Corona Discharge Ion Source, in an Urban Atmosphere and in a Teflon Film Chamber

    Science.gov (United States)

    Alves, M.; Hanson, D. R.; Grieves, C.; Ortega, J. V.

    2015-12-01

    Amines and ammonia are an important group of molecules that can greatly affect atmospheric particle formation that can go on to impact cloud formation and their scattering of thermal and solar radiation, and as a result human health and ecosystems. In this study, an Ambient Pressure Mass Spectrometer (AmPMS) that is selective and sensitive to molecules with a high proton affinity, such as amines, was coupled with a newly built corona discharge ion source. AmPMS was used to monitor many different nitrogenous compound that are found in an urban atmosphere (July 2015, Minneapolis), down to the single digit pmol/mol level. Simultaneous to this, a proton transfer mass spectrometer also sampled the atmosphere through an inlet within 20 m of the AmPMS inlet. In another set of studies, a similar AmPMS was attached to a large Teflon film chamber at the Atmospheric Chemistry Division at NCAR (August 2015, Boulder). Exploratory studies are planned on the sticking of amines to the chamber walls as well as oxidizing the amine and monitoring products. Depending on the success of these studies, results will be presented on the reversability of amine partitioning and mass balance for these species in the chamber.

  11. Optimum exposure time for speckle imaging through the atmosphere using the bispectrum technique

    Science.gov (United States)

    McCrae, Kimberley A.; Roggemann, Michael C.; Welsh, Byron M.

    1996-10-01

    Bispectrum speckle imaging uses the average of many short exposure frames to eliminate atmospheric effects on images. Unfortunately, objects are often dim, requiring longer exposure times to collect enough photons to reconstruct an image. We investigate this trade-off using a computer simulation to create image frames under various seeing conditions, then determine the exposure time that yields the highest signal-to-noise ratio for the unbiased speckle interferometry estimator and the lowest mean square error for the reconstructed phase. We have found that for low light levels and for high read noise cases the optimum exposure time is greater than one Greenwood coherence time.

  12. Detailed diesel exhaust characteristics including particle surface area and lung deposited dose for better understanding of health effects in human chamber exposure studies

    Science.gov (United States)

    Wierzbicka, Aneta; Nilsson, Patrik T.; Rissler, Jenny; Sallsten, Gerd; Xu, Yiyi; Pagels, Joakim H.; Albin, Maria; Österberg, Kai; Strandberg, Bo; Eriksson, Axel; Bohgard, Mats; Bergemalm-Rynell, Kerstin; Gudmundsson, Anders

    2014-04-01

    Several diesel exhaust (DE) characteristics, comprising both particle and gas phase, recognized as important when linking with health effects, are not reported in human chamber exposure studies. In order to understand effects of DE on humans there is a need for better characterization of DE when performing exposure studies. The aim of this study was to determine and quantify detailed DE characteristics during human chamber exposure. Additionally to compare to reported DE properties in conducted human exposures. A wide battery of particle and gas phase measurement techniques have been used to provide detailed DE characteristics including the DE particles (DEP) surface area, fraction and dose deposited in the lungs, chemical composition of both particle and gas phase such as NO, NO2, CO, CO2, volatile organic compounds (including aldehydes, benzene, toluene) and polycyclic aromatic hydrocarbons (PAHs). Eyes, nose and throat irritation effects were determined. Exposure conditions with PM1 (load. This highlights the need for detailed and standardized approach for measuring and reporting of DE properties. Eyes irritation effects, most probably caused by aldehydes in the gas phase, as well as nose irritation were observed at exposure levels below current occupational exposure limit values given for exhaust fumes. Reporting detailed DE characteristics that include DEP properties (such as mass and number concentration, size resolved information, surface area, chemical composition, lung deposited dose by number, mass and surface) and detailed gas phase including components known for their carcinogenic and irritation effect (e.g. aldehydes, benzene, PAHs) can help in determination of key parameters responsible for observed health effects and comparison of chamber exposure studies.

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

    CERN Document Server

    Chang, C; 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; Nagarajan, S; Peng, E; Rasmussen, A P; Shmakova, M; Sylvestre, N; Todd, N; Young, M

    2012-01-01

    The synoptic imaging survey proposed for the Large Synoptic Survey Telescope (LSST) will generate large numbers of short exposure ($\\simeq$15 seconds) images. A primary science driver for this project is to measure the cosmic shear signal from weak lensing to extreme accuracy. One difficulty, however, is that in these short exposure images, the spatial variation of the Point Spread Function (PSF) shapes may be dominated by the atmosphere, in addition to optics errors. In particular, the atmosphere generates stochastic structures on a wide range of angular scales. Since the PSF patterns in these images can only be inferred by interpolating the sparsely sampled stars in the field, these multi-scale, complex patterns from the atmosphere complicates the PSF interpolation problem. In this paper we present a new method, PSFent, for interpolating atmospheric PSF shape parameters, based on reconstructing underlying shape parameter maps with a multi-scale maximum entropy algorithm. We demonstrate, using images from th...

  14. Characterization of corrosion products formed on steels in the first months of atmospheric exposure

    OpenAIRE

    Antunes Renato Altobelli; Costa Isolda; Faria Dalva Lúcia Araújo de

    2003-01-01

    The corrosion products of carbon steel and weathering steel exposed to three different types of atmospheres, at times ranging from one to three months, have been identified. The steels were exposed in an industrial site, an urban site (São Paulo City, Brazil), and a humid site. The effect of the steel type on the corrosion products formed in the early stages of atmospheric corrosion has been evaluated. The corrosion products formed at the various exposure locations were characterized by Raman...

  15. Programs to calculate human radiation exposure caused by atmospheric diffusion of radioactive substances

    International Nuclear Information System (INIS)

    This report describes - with a discussion on the mathematical background of transport processes near the ground - a program system START which make possible the interactive calculation of human radiation exposure resulting from the accidental release of radioactivity from nuclear facilities into the atmosphere. The system supplies data relevant immediately after the release on the whole-body and thyroid exposure of adults caused by inhalation and γ-submersion. (orig./HP)

  16. Radiation exposure of airline crew members to the atmospheric ionizing radiation environment

    International Nuclear Information System (INIS)

    A study of radiation exposures in the ionizing radiation environment of the atmosphere is currently in progress for the Italian civil aviation flight personnel. After a description of the considered data sources/ the philosophy of the study is presented/ and an overview is given of the data processing with regard to flight routes/ the computational techniques for radiation dose evaluation along the flight paths and for the exposure matrix building/ along with an indication of the results that the study should provide.

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

    International Nuclear Information System (INIS)

    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 bio solids, 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 bio solids to land. This was done by applying three different types of bio solids 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.

  18. The multimedia models for the evaluation of exposure bond to the atmospheric emissions of classified installations

    International Nuclear Information System (INIS)

    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.)

  19. Study of atmospheric tritium transfers in lettuce: kinetic study, equilibrium and organic incorporation during a continuous atmospheric exposure

    International Nuclear Information System (INIS)

    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)

  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. Atmospheric Dispersion Coefficients and Radiological and Toxicological Exposure Methodology for Use in Tank Farms

    International Nuclear Information System (INIS)

    This report presents the atmospheric dispersion coefficients used for Tank Farms safety analyses. The development of the coefficients is also presented. The report contains the necessary documentation for meeting Software QA requirements for the GXQ software. The basic equations for calculating radiological doses and chemical exposures are included

  2. On the capability of in-situ exposure in an environmental scanning electron microscope for investigating the atmospheric corrosion of magnesium

    International Nuclear Information System (INIS)

    The feasibility of environmental scanning electron microscope (ESEM) in studying the atmospheric corrosion behavior of 99.97% Mg was investigated. For reference, ex-situ exposure was performed. A model system was designed by spraying few salt particles on the metal surface and further promoting the corrosion process using platinum (Pt) deposition in the form of 1×1×1 µm3 dots around the salt particles to create strong artificial cathodic sites. The results showed that the electron beam play a significant role in the corrosion process of scanned regions. This was attributed to the irradiation damage occurring on the metal surface during the ESEM in-situ experiment. After achieving to a reliable process route, in a successful attempt, the morphology and composition of the corrosion products formed in-situ in the ESEM were in agreement with those of the sample exposed ex-situ. - Highlights: • The feasibility of in-situ microscopy and atmospheric corrosion exposures of pure Mg in an ESEM are examined. • A model system was designed using NaCl particles on parts of the metal surface and promoting the corrosion process by depositing 1×1×1 µm3 Pt dots to create strong artificial cathodic sites. • The electron beam used for ESEM imaging affects the in-situ corrosion process. • A proper cleaning procedure for the sample and microscope chamber reducing carbon contamination makes the results from the ESEM in-situ exposures comparable to ex-situ exposures

  3. Use of high-volume outdoor smog chamber photo-reactors for studying physical and chemical atmospheric aerosol formation and composition

    Science.gov (United States)

    Borrás, E.; Ródenas, M.; Vera, T.; Muñoz, A.

    2015-12-01

    The atmospheric particulate matter has a large impact on climate, biosphere behaviour and human health. Its study is complex because of large number of species are present at low concentrations and the continuous time evolution, being not easily separable from meteorology, and transport processes. Closed systems have been proposed by isolating specific reactions, pollutants or products and controlling the oxidizing environment. High volume simulation chambers, such as EUropean PHOtoREactor (EUPHORE), are an essential tool used to simulate atmospheric photochemical reactions. This communication describes the last results about the reactivity of prominent atmospheric pollutants and the subsequent particulate matter formation. Specific experiments focused on organic aerosols have been developed at the EUPHORE photo-reactor. The use of on-line instrumentation, supported by off-line techniques, has provided well-defined reaction profiles, physical properties, and up to 300 different species are determined in particulate matter. The application fields include the degradation of anthropogenic and biogenic pollutants, and pesticides under several atmospheric conditions, studying their contribution on the formation of secondary organic aerosols (SOA). The studies performed at the EUPHORE have improved the mechanistic studies of atmospheric degradation processes and the knowledge about the chemical and physical properties of atmospheric particulate matter formed during these processes.

  4. 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.......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...... 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...

  5. EXPOSURE TO CARBONIC GAS ENRICHED ATMOSPHERE OR ELECTRICAL WATER BATH TO STUN OR KILL CHICKENS

    OpenAIRE

    JP Nicolau; MF Pinto; EHG Ponsano; SHV Perri; M Garcia Neto

    2015-01-01

    ABSTRACTThe objective of this study was to compare the effects of two methods (electrical water bath or carbonic gas atmosphere) for stunning or killing broiler chickens prior to bleeding on weight loss due to bleeding and meat traits. A completely randomized design with 2 x 2 factorial arrangement (electrical or gas system x stunning or killing) was applied. The time required for stunning and killing and the birds' behavior were evaluated for the gas exposure method. The birds killed by the ...

  6. Overestimation of soil CO2 fluxes from closed chamber measurements at low atmospheric turbulence biases the diurnal pattern and the annual soil respiration budget

    Science.gov (United States)

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

    2016-04-01

    Precise quantification of the diurnal and seasonal variation of soil respiration (Rs) is crucial to correctly estimate annual soil carbon fluxes as well as to correctly interpret the response of Rs to biotic and abiotic factors on different time scale. In this study we found a systematic effect of low atmospheric turbulence on continuous hourly Rs measurements with closed chambers throughout one year in a temperate Danish beech forest. Using friction velocity (u⋆) measured at the site above the canopy, we filtered out chamber flux data measured at low atmospheric turbulence. The non-filtered data showed a clear diurnal pattern of Rs across all seasons with highest fluxes during night time suggesting an implausible negative temperature sensitivity of Rs. When filtering out data at low turbulence, the annually averaged diurnal pattern changed, such that the highest Rs fluxes were seen during day time, i.e. following the course of soil temperatures. This effect on the diurnal pattern was due to low turbulence primarily occurring during night time. We calculated different annual Rs budgets by filtering out fluxes for different levels of u⋆. The highest annual Rs budget was found when including all data and it decreased with an increasing u⋆ filter threshold. Our results show that Rs was overestimated at low atmospheric turbulence throughout the year and that this overestimation considerably biased the diurnal pattern of Rs and led to an overestimation of the annual Rs budget. Thus we recommend that that any analysis of the diurnal pattern of Rs must consider overestimation of Rs at low atmospheric turbulence, to yield unbiased diurnal patterns. This is crucial when investigating temperature responses and potential links between CO2 production and Rs on a short time scale, but also for correct estimation of annual Rs budgets. Acknowledgements: This study was funded by the free Danish Ministry for Research, Innovation and higher Education, the free Danish Research

  7. Exposure to the atmospheric ionizing radiation environment: a study on Italian civilian aviation flight personnel

    International Nuclear Information System (INIS)

    A study of the effects of high-LET, low-dose and low-dose-rate ionizing radiation and associated risk analysis is underway. This study involves analyzing the atmospheric ionizing radiation exposure (including high-energy neutrons) and associated effects for members of civilian aviation flight personnel, in an attempt to better understand low-dose long-term radiation effects on human subjects. The study population includes all Italian civilian airline flight personnel, both cockpit and cabin crew members, whose work history records and actual flights (route, aircraft type, and date for each individual flight for each person where possible) are available. The dose calculations are performed along specific flight legs, taking into account the actual flight profiles for all different routes and the variations with time of solar and geomagnetic parameters. Dose values for each flight are applied to the flight history of study participants in order to estimate the individual annual and lifetime occupational radiation dose. An update of the study of the physical atmospheric ionizing radiation exposure is given here, in terms of environmental modeling, flight routes, radiation dose evaluation along different flight paths, and exposure matrix construction. The exposure analysis is still in progress, and the first results are expected soon

  8. The effects of air pollution and climatic factors on atmospheric corrosion of marble under field exposure

    International Nuclear Information System (INIS)

    The atmospheric corrosion of marble was evaluated in terms of SO2 concentration as air pollution and climatic factors such as rainfall, relative humidity, temperature and so on under the field exposure. Marble of calcite type (CaCO3) was exposed to outdoor atmospheric environment with and without a rain shelter at four test sites in the southern part of Vietnam for 3-month, 1- and 2-year periods from July 2001 to September 2003. The thickness loss of marble was investigated gravimetrically. X-ray diffraction and X-ray fluorescent methods were applied to study corrosion products on marble. The corrosion product of marble was only gypsum (CaSO4 . 2H2O) and was washed out by rain under the unsheltered exposure condition. It was found that the most substantial factors influencing the corrosion of marble were rainfall, SO2 concentration in the air and relative humidity. Based on the results obtained, we estimated the dose-response functions for the atmospheric corrosion of marble in the southern part of Vietnam

  9. Lung cancer mortality and exposure to atmospheric aerosol particles in Guangzhou, China

    Science.gov (United States)

    Tie, Xuexi; Wu, Dui; Brasseur, Guy

    In recent years, China and other emerging countries have been experiencing severe air pollution problems with high concentrations of atmospheric aerosol particles. Satellite measurements indicate that the aerosol loading of the atmosphere in highly populated regions of China is about 10 times higher than, for example, in Europe and in the Eastern United States. The exposure to extremely high aerosol concentrations might lead to important human health effects, including respiratory and cardiovascular diseases as well as lung cancers. Here, we analyze 52-year historical surface measurements of haze data in the Chinese city of Guangzhou, and show that the dramatic increase in the occurrence of air pollution events between 1954 and 2006 has been followed by a large enhancement in the incidence of lung cancer.

  10. [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. PMID:27078934

  11. Image analysis of atmospheric corrosion of field exposure high strength aluminium alloys

    Science.gov (United States)

    Tao, Lei; Song, Shizhe; Zhang, Xiaoyun; Zhang, Zheng; Lu, Feng

    2008-08-01

    The corrosion morphology image acquisition system which can be used in the field was established. In Beijing atmospheric corrosion exposure station, the image acquisition system was used to capture the early stage corrosion morphology of five types of high strength aluminium alloy specimens. After the denoise treatment, wavelet-based image analysis method was applied to decompose the improved images and energies of sub-images were extracted as character information. Based on the variation of image energy values, the corrosion degree of aluminium alloy specimens was qualitatively and quantitatively analyzed. The conclusion was basically identical with the result based on the corrosion weight loss. This method is supposed to be effective to analysis and quantify the corrosion damage from image of field exposure aluminium alloy specimens.

  12. Radiation exposure of airline crew members to the atmospheric ionizing radiation environment

    International Nuclear Information System (INIS)

    All risk assessment techniques for possible health effects from low dose rate radiation exposure should combine knowledge both of the radiation environment and of the biological response, whose effects (e.g. carcinogenesis) are usually evaluated through mathematical models and/or animal and cell experiments. Data on human exposure to low dose rate radiation exposure and its effects are not readily available, especially with regards to stochastic effects, related to carcinogenesis and therefore to cancer risks, for which the event probability increases with increasing radiation exposure. The largest source of such data might be airline flight personnel, if enrolled for studies on health effects induced by the cosmic-ray generated atmospheric ionizing radiation, whose total dose, increasing over the years, might cause delayed radiation-induced health effects, with the high-LET and highly ionizing neutron component typical of atmospheric radiation. In 1990 flight personnel has been given the status of 'occupationally exposed to radiation' by the International Commission for Radiation Protection (ICRP), with a received radiation dose that is at least twice larger than that of the general population. The studies performed until now were limited in scope and cohort size, and moreover no information whatsoever on radiation occupational exposure (e.g. dose, flight hours, route haul, etc.) was used in the analysis, so no correlation has been until now possible between atmospheric ionizing radiation and (possibly radiation-induced) observed health effects. Our study addresses the issues, by considering all Italian civilian airline flight personnel, both cockpit and cabin crew members, with about 10,000 people selected, whose records on work history and actual flights (route, aircraft type, date, etc. for each individual flight for each person where possible) are considered. Data on actual flight routes and profiles have been obtained for the whole time frame. The actual dose

  13. 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

    International Nuclear Information System (INIS)

    Most available exposure-response relationships for assessing crop loss due to elevated ozone (O3) have been established using data from chamber and open-top chamber experiments, using a simulated constant O3 concentration exposure (square wave), which is not consistent with the diurnal variation of O3 concentration that occurs in nature. We investigated the response of oilseed rape (Brassica napus L.) to O3 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 O3 concentration and accumulated O3 concentration above 40 ppb (AOT40), our results show that O3 at CF100D reduced biomass and number of pods/plant more than O3 at CF100. Both O3 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 O3 exposure may underestimate O3 effects on biomass and yields. - Diurnal variation of O3 concentration should be considered when designing O3 exposure experiment

  14. 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.

  15. On the capability of in-situ exposure in an environmental scanning electron microscope for investigating the atmospheric corrosion of magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Esmaily, M., E-mail: mohsen.esmaily@chalmers.se [Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Mortazavi, N. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Shahabi-Navid, M.; Svensson, J.E.; Johansson, L.G. [Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Halvarsson, M. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden)

    2015-06-15

    The feasibility of environmental scanning electron microscope (ESEM) in studying the atmospheric corrosion behavior of 99.97% Mg was investigated. For reference, ex-situ exposure was performed. A model system was designed by spraying few salt particles on the metal surface and further promoting the corrosion process using platinum (Pt) deposition in the form of 1×1×1 µm{sup 3} dots around the salt particles to create strong artificial cathodic sites. The results showed that the electron beam play a significant role in the corrosion process of scanned regions. This was attributed to the irradiation damage occurring on the metal surface during the ESEM in-situ experiment. After achieving to a reliable process route, in a successful attempt, the morphology and composition of the corrosion products formed in-situ in the ESEM were in agreement with those of the sample exposed ex-situ. - Highlights: • The feasibility of in-situ microscopy and atmospheric corrosion exposures of pure Mg in an ESEM are examined. • A model system was designed using NaCl particles on parts of the metal surface and promoting the corrosion process by depositing 1×1×1 µm{sup 3} Pt dots to create strong artificial cathodic sites. • The electron beam used for ESEM imaging affects the in-situ corrosion process. • A proper cleaning procedure for the sample and microscope chamber reducing carbon contamination makes the results from the ESEM in-situ exposures comparable to ex-situ exposures.

  16. Construction, calibration and testing of a ionization chamber for exposure measurement of X and gamma rays in the energy range from 40 keV up to 1250KEV

    International Nuclear Information System (INIS)

    An unsealed thimble ionization chamber with connecting cable was designed, manufactured and tested at the IRD/CNEN, for exposure or exposure rate measurement of X or gamma rays in the energy range from 40 keV up to Cobalt-60. Recommendations given by IEC,TC-62(1974) were used as acceptance tests of the ionization chamber for use as a tertiary standard (field class instruments) in radiation therapy. In addition, intercomparison with commercially available chambers of reference class type were carried out in respect to field size dependence, energy dependence, short and long term stability.The results of those tests indicated the usefulness of the developed ionization chamber as a tertiary standard. (author)

  17. 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 stil

  18. In situ variation of cervical mucus pH during exposure to atmospheric air

    Directory of Open Access Journals (Sweden)

    Correa C.H.M.

    2001-01-01

    Full Text Available The objective of the present study was to determine if exposure of cervical mucus to air during specular examination could modify mucus pH. Detection of changes is justified because of their possible interference with sperm-mucus interaction, since an acidic pH is unfavorable to sperm penetration and is associated with infertility due to the cervical factor. Twenty women with good quality mucus were evaluated. pH measurements of ecto- and endocervical mucus were made in situ using a glass electrode after 0-, 5- and 10-min exposure to air. There was a progressive alkalinization of mucus pH. Mean values of ectocervical mucus pH were 6.91, 7.16 and 7.27, while mean values of endocervical mucus pH were 7.09, 7.34 and 7.46 at 0, 5 and 10 min, respectively. Significant differences were found between the mean values obtained at 0 and 5 min, and at 0 and 10 min (P<0.05, whereas the differences in mean values at 5 and 10 min were not significant at either site. We conclude that 5 to 10 min of exposure to atmospheric air affects cervical mucus pH in a significant way. Since tests used to evaluate sperm-mucus interaction generally have not considered this possibility, we suggest that they should be performed immediately after mucus collection in order to avoid misinterpretation of the results.

  19. Automated Electrostatics Environmental Chamber

    Science.gov (United States)

    Calle, Carlos; Lewis, Dean C.; Buchanan, Randy K.; Buchanan, Aubri

    2005-01-01

    The Mars Electrostatics Chamber (MEC) is an environmental chamber designed primarily to create atmospheric conditions like those at the surface of Mars to support experiments on electrostatic effects in the Martian environment. The chamber is equipped with a vacuum system, a cryogenic cooling system, an atmospheric-gas replenishing and analysis system, and a computerized control system that can be programmed by the user and that provides both automation and options for manual control. The control system can be set to maintain steady Mars-like conditions or to impose temperature and pressure variations of a Mars diurnal cycle at any given season and latitude. In addition, the MEC can be used in other areas of research because it can create steady or varying atmospheric conditions anywhere within the wide temperature, pressure, and composition ranges between the extremes of Mars-like and Earth-like conditions.

  20. Joint measurement of the atmospheric muon flux through the Puy de Dôme volcano with plastic scintillators and Resistive Plate Chambers detectors

    Science.gov (United States)

    Ambrosino, F.; Anastasio, A.; Bross, A.; Béné, S.; Boivin, P.; Bonechi, L.; Cârloganu, C.; Ciaranfi, R.; Cimmino, L.; Combaret, Ch.; D'Alessandro, R.; Durand, S.; Fehr, F.; Français, V.; Garufi, F.; Gailler, L.; Labazuy, Ph.; Laktineh, I.; Lénat, J.-F.; Masone, V.; Miallier, D.; Mirabito, L.; Morel, L.; Mori, N.; Niess, V.; Noli, P.; Pla-Dalmau, A.; Portal, A.; Rubinov, P.; Saracino, G.; Scarlini, E.; Strolin, P.; Vulpescu, B.

    2015-11-01

    The muographic imaging of volcanoes relies on the measured transmittance of the atmospheric muon flux through the target. An important bias affecting the result comes from background contamination mimicking a higher transmittance. The MU-RAY and TOMUVOL collaborations measured independently in 2013 the atmospheric muon flux transmitted through the Puy de Dôme volcano using their early prototype detectors, based on plastic scintillators and on Glass Resistive Plate Chambers, respectively. These detectors had three (MU-RAY) or four (TOMUVOL) detection layers of 1 m2 each, tens (MU-RAY) or hundreds (TOMUVOL) of nanosecond time resolution, a few millimeter position resolution, an energy threshold of few hundreds MeV, and no particle identification capabilities. The prototypes were deployed about 1.3 km away from the summit, where they measured, behind rock depths larger than 1000 m, remnant fluxes of 1.83±0.50(syst)±0.07(stat) m-2 d-1 deg-2 (MU-RAY) and 1.95±0.16(syst)±0.05(stat) m-2 d-1 deg-2 (TOMUVOL), that roughly correspond to the expected flux of high-energy atmospheric muons crossing 600 meters water equivalent (mwe) at 18° elevation. This implies that imaging depths larger than 500 mwe from 1 km away using such prototype detectors suffer from an overwhelming background. These measurements confirm that a new generation of detectors with higher momentum threshold, time-of-flight measurement, and/or particle identification is needed. The MU-RAY and TOMUVOL collaborations expect shortly to operate improved detectors, suitable for a robust muographic imaging of kilometer-scale volcanoes.

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

    International Nuclear Information System (INIS)

    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.

  2. Risk assessment of atmospheric heavy metals exposure in Baotou, a typical industrial city in northern China.

    Science.gov (United States)

    Li, Kexin; Liang, Tao; Wang, Lingqing

    2016-06-01

    Industrial activities have led to serious air pollution and the potentially toxic elements in atmospheric particles can cause various health problems to humans. In this study, inhalable particulate matter (PM10) and fine particles (PM2.5) were collected from four typical sites in Baotou, an industrial city in northern China. We investigated both the mass concentrations of particulate matter and the concentrations of heavy metals (Cr, Ni, Pb, Cd, Cu, Mn, Co, and Zn) in the collected samples. We assessed the public health risks associated with atmospheric heavy metal exposure. The results showed that the mass concentrations of PM2.5 and PM10 as well as these heavy metal concentrations varied notably influenced by the prevailing wind directions. Among the studied metals, Zn, Mn, Pb, and Cr were the main metal pollutants in both PM10 and PM2.5. The results of the health assessment showed that the eight heavy metals studied pose significant non-carcinogenic risks and Cr, Cd, and Co pose lifetime lung cancer risks to local residents, especially to children. PMID:26350673

  3. Size-dependent atmospheric deposition and inhalation exposure of particle-bound organophosphate flame retardants.

    Science.gov (United States)

    Luo, Pei; Bao, Lian-Jun; Guo, Ying; Li, Shao-Meng; Zeng, Eddy Y

    2016-01-15

    Atmospheric size-fractionated particles were collected at different heights in an e-waste recycling zone (QY) and urban Guangzhou (GZ), China and analyzed for organophosphate flame retardants (OPFRs). The total air concentrations of eight OPFRs were 130±130 and 138±127 ng m(-3) in QY and GZ, respectively. Compositional profiles of chlorinated OPFRs were different between QY and GZ, but the size distribution patterns of all OPFRs were not significantly different at different heights. Estimated atmospheric deposition fluxes of OPFRs were 51±67 and 55±13 μg m(-2) d(-1) in QY and GZ, respectively, and the coarse particles (Dp>1.8 μm) dominated both the dry and wet deposition fluxes. Moreover, not all particle-bound OPFRs were inhalable and deposited in the human respiratory tract. The calculated inhalation doses of OPFRs were much lower than the reference doses, suggesting that potential health risk due to inhalation exposure to particle-bound OPFRs in the e-waste recycling zone and urban site was low. PMID:26414926

  4. Characterization of corrosion products formed on steels in the first months of atmospheric exposure

    Directory of Open Access Journals (Sweden)

    Renato Altobelli Antunes

    2003-06-01

    Full Text Available The corrosion products of carbon steel and weathering steel exposed to three different types of atmospheres, at times ranging from one to three months, have been identified. The steels were exposed in an industrial site, an urban site (São Paulo City, Brazil, and a humid site. The effect of the steel type on the corrosion products formed in the early stages of atmospheric corrosion has been evaluated. The corrosion products formed at the various exposure locations were characterized by Raman microscopy, X-Ray diffraction (XRD and their morphology was observed by Scanning Electron Microscopy (SEM. Three regions of different colours (yellow, black and red have been identified over the steel coupons by Raman microscopy. Analysis carried out on each of these areas led to the characterization of the correspondent oxide/hydroxide phases. The main phases present were lepidocrocite (g-FeOOH and goethite (a-FeOOH. Small amounts of magnetite (Fe3O4 were also eventually encountered.

  5. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rong

    2015-06-01

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

  6. 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.

  7. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    International Nuclear Information System (INIS)

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

  8. 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.

  9. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  10. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  11. Real-time detection of nitrous acid (HONO) by PTR-MS - a comparison with LOPAP measurements in the atmosphere simulation chamber SAPHIR

    International Nuclear Information System (INIS)

    Full text: Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) is a chemical ionization mass spectrometry technique that uses proton transfer reactions with H3O+ ions for real-time measurements of trace gases in air. These reactions are almost invariably efficient for all compounds with a higher proton affinity than water. This includes the large majority of polyatomic volatile organic molecules with the exception of small aliphatic hydrocarbons. In this work we expand the PTR-MS technique to the measurement of gaseous nitrous acid (HONO), a key inorganic species in the troposphere that acts as a source of OH radicals via photolysis. The chemical ionization detection scheme for HONO was studied in detail using a Selected Ion Flow Drift Tube (SIFDT). This information was then applied to subsequent measurements of HONO with a PTR-MS instrument in the atmosphere simulation chamber SAPHIR and in ambient air at Juelich (Germany). The measurements were compared with data from a long path absorption photometer (LOPAP). The agreement with the well-established LOPAP technique was excellent. Data illustrating the performance characteristics of the PTR-MS are presented demonstrating its ability to perform gaseous HONO measurements with a detection limit of ∼ 100 pptV at 20 s - time resolution. (author)

  12. Second organic aerosol formation by irradiation of α-pinene-NOx-H2O in an indoor smog chamber for atmospheric chemistry and physics

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhe; HAO JiMing; LI JunHua; WU Shan

    2008-01-01

    Ozone(O3) and secondary organic aerosol (SOA) are considered to be the most serious secondary air pollutants of concern in most metropolitan areas, as well as for Beijing. In this study, O3 and SOA for-mation potential of α-pinene, the most abundant biogenic VOCs, is investigated at Tsinghua Indoor Chamber Facility. The experiments were conducted under atmospheric relevant HCs/NOx ratios in both presence and absence of ammonia sulfate seed aerosol. A Scanning Mobility Particle Sizer system (3936, TSI) and a Condensation Particle Counter (3010, TSI) were used to study the SOA formation and a gas chromatograph (GC) equipped with a DB-5 column and a flame ionization detector (FID) was used to measure α-pinene simultaneously. The results show that the presence of ammonia sulfate seed aerosol did not change the formation trend of O2, but significantly contribute to SOA formation. A strong linear relationship (r2=0.90) between SOA yield enhancement (△Y*) and surface concentration of seed aernsol (PMi,s)has been found, denoting that the PMi,s is the control factor for SOA yield en-hancement. And the possible reason for the enhancement is acid-catalyzed heterogeneous reactions.

  13. 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 increa

  14. Report from Workshop on VOCs in diving chambers

    International Nuclear Information System (INIS)

    This report of the 'Setting the Standards' workshop on the problems of volatile organic compounds (VOCs) in diving in offshore operations, sponsored jointly by the UK Health and Safety Executive Offshore Safety Division and the Stolt Rockwater Joint Venture, gives details of the papers presented covering the chemical contamination of diver's atmosphere, sampling protocols and methods, analytical procedures used for VOCs in hyperbaric chambers, and contamination in buildings. The setting of exposure limits in the UK, the derivation of threshold limiting values (TVLs), the selection of Tenax tubes for atmospheric sampling, organic contaminant monitoring, and NASA's approach to contamination in the space environment are examined, and dealing with contamination problems in a submarine atmosphere, and the simulation of a condensate spillage in a diving bell are discussed. Guidelines for the measurement of VOCs in hyperbaric chambers are given in the appendices

  15. 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.

  16. Vacuum chamber

    International Nuclear Information System (INIS)

    A detailed description is given of the vacuum chamber of the so-called experimental equipment DEMAS (double-arm-time-of-flight spectrometer) at the heavy ion accelerator U-400 at the JINR-Dubna. (author)

  17. Assessment of exposures to 131I in the continental United States resulting from the Nevada atmospheric nuclear tests

    International Nuclear Information System (INIS)

    The National Cancer Institute (NCI) is conducting an assessment of the exposure to 131I that the American people received from the fallout resulting from the atmospheric bomb tests carried out at the Nevada Test Site (NTS). It is estimated that about 5 EBq of 131I were released into the atmosphere as a result of approximately 100 tests carried out mainly in the 1950s. The most important source of human exposure from fallout 131I was due to the ingestion of cows' milk but other routes of exposure (ingestion of goats' milk, leafy vegetables, eggs, and cottage cheese as well as inhalation) are also considered. The exposure to 131I are assessed on a test-by-test and county-by-county basis. In order to make these estimates for locations throughout the United States, it is necessary to determine: The activities of 131I deposited on soil and vegetation, the amount of 131I consumed by dairy cows and the resulting 131I concentrations in cow's milk, and the 131I ingested by people. The overall methodology currently used in the assessment of the 131I exposures is presented. Particular attention is devoted to the methodology developed to estimate the intake of contaminated pasture by dairy cows, milk production, and milk distribution for each county of the continental United States during the 1950s

  18. 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

  19. Experiments with a spark chamber

    International Nuclear Information System (INIS)

    The authors constructed an experimental spark chamber with a useable volume of 7 x 7 x 5 cm having six parallel 2-mm thick stainless steel plates. The distance between each plate is 8 mm. The chamber is filled with neon under a pressure of one atmosphere. On applying a pulse of about 10 keV on the plates immediately after the passage of a charged particle through the chamber, sparks form along the trajectory of the particle and may easily be photographed. The chamber was first used with cosmic ray μ mesons and then put into the π-meson beam of the SATURN synchrocyclotron. The efficiency of the chamber as a function of voltage and retardation of the applied electric pulse and the dead time are given. The first results obtained with a chamber of 10-litre volume are also presented. (author)

  20. 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.

  1. 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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Kurita, Hirofumi; Miyachika, Saki; Yasuda, Hachiro; Takashima, Kazunori; Mizuno, Akira

    2015-12-01

    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.

  4. Robert Chambers

    NARCIS (Netherlands)

    K. Biekart (Kees); D.R. Gasper (Des)

    2013-01-01

    textabstractProfessor Robert Chambers is a Research Associate at the Institute of Development Studies (IDS), University of Sussex (Brighton, UK), where he has been based for the last 40 years, including as Professorial Research Fellow. He became involved in the field of development management in the

  5. Factors influencing the durability of anti corrosive painting systems on steel in atmospheric exposures

    International Nuclear Information System (INIS)

    The experimental results obtained with ten typical painting systems exposed during eight years in ten Spanish atmospheres are summarized. The effects of the type of atmosphere, characteristics of the paint systems (generic type and thickness), and teel surface preparation in the anti corrosive performance are analysed. (Author) 6 refs

  6. Characterisation of initial atmospheric corrosion carbon steels by field exposure and laboratory simulation

    International Nuclear Information System (INIS)

    The early stages of the evolution of atmospheric corrosion of carbon steels exposed in both a laboratory simulated and a natural atmosphere environment in Shenyang have been observed by in situ scanning electron microscopy. In the case of laboratory cyclic wet-dry tests, even though the chloride content level is very low, filiform corrosion is initiated in the early stage. The filiform corrosion grows in random directions, forming a network of ridges. White nodules nucleate and grow on the ridges during continued corrosion and eventually connect with each other to form the initial corrosion scale. Pits were also found on the surface beneath corrosion products. In the case of a natural atmospheric environment, both filiform corrosion and other localized corrosion, such as pitting and inter-granular attack take place in the initial stage. It is obvious that there is variety of localized corrosion in the initial stage of atmospheric corrosion

  7. Ionization chamber

    International Nuclear Information System (INIS)

    An ionization chamber X-ray detector is described. It comprises a flat cathode sheet parallel to an anode which has a perforated insulating layer on its surface. An open grid, a thin perforated metal sheet is disposed on the insulating layer - the perforations of the layer and sheet are aligned. There is a detector gas and means for maintaining the grid at an electric potential between that of the anode and cathode and for measuring the current flow from the anode to the cathode. The grid shields the anode from the electric field produced by the positive ions which flow towards the cathode and this permits an independent measurement of the electron current flowing to the anode; even when the X-ray pulse length is not much shorter than the ion drift time. The recovery time of the ionization chamber is thus decreased by several orders of magnitude over previous chambers. The grid will normally be fixed to the anode and by shielding the anode from the cathode electric field, tends to eliminate capacitive microphone currents which would otherwise flow in the anode circuit. (U.K.)

  8. Enhanced solubility and ecological impact of atmospheric phosphorus deposition upon extended seawater exposure.

    Science.gov (United States)

    Mackey, Katherine R M; Roberts, Kathryn; Lomas, Michael W; Saito, Mak A; Post, Anton F; Paytan, Adina

    2012-10-01

    Atmospheric P solubility affects the amount of P available for phytoplankton in the surface ocean, yet our understanding of the timing and extent of atmospheric P solubility is based on short-term leaching experiments where conditions may differ substantially from the surface ocean. We conducted longer- term dissolution experiments of atmospheric aerosols in filtered seawater, and found up to 9-fold greater dissolution of P after 72 h compared to instantaneous leaching. Samples rich in anthropogenic materials released dissolved inorganic P (DIP) faster than mineral dust. To gauge the effect of biota on the fate of atmospheric P, we conducted field incubations with aerosol samples collected in the Sargasso Sea and Red Sea. In the Sargasso Sea phytoplankton were not P limited, and biological activity enhanced DIP release from aerosols, and aerosols induced biological mineralization of dissolved organic P in seawater, leading to DIP accumulation. However, in the Red Sea where phytoplankton were colimited by P and N, soluble P was rapidly consumed by phytoplankton following aerosol enrichment. Our results suggest that atmospheric P dissolution could continue over multiple days once reaching the surface ocean, and that previous estimates of atmospheric P deposition may underestimate the contribution from this source. PMID:22574853

  9. Atmospheric Corrosion of Painted Galvanized and 55%Al-Zn Steel Sheets: Results of 12 Years of Exposure

    Directory of Open Access Journals (Sweden)

    C. I. Elsner

    2012-01-01

    Full Text Available Zinc or 55%Al-Zn alloy-coated steel sheets, either bare or covered by different painting systems, have been exposed for 12 years to the action of the urban atmosphere at the CIDEPINT station located in La Plata (34° 50′ South, 57° 53′, West, province of Buenos Aires, Argentina. The samples exposed surface was evaluated through periodical visual inspections, standardized adhesion tests, and electrochemical impedance measurements. The ambient variables monitored were average annual rains and temperatures, time of wetness, sulphur and chloride concentration, relative humidity, and speed and direction of the winds. It was found that in this atmosphere, the corrosion resistance of the bare 55% Al-Zn/steel sheets was higher than of the galvanized steel, and the polyurethane painting system was more protective than the alkyd and epoxy ones, which degraded after 6-7 years of exposure.

  10. 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. PMID:20967132

  11. 222Rn in the outdoor atmosphere - trends, variations and radiation exposure

    International Nuclear Information System (INIS)

    The long-term monitoring of 222Rn in the atmosphere of Bratislava showed that the annual average values of the volume activity of 222Rn vary up to 27 % around the average value 5,5 Bq.m-3. The substantial change of this average value is possible to expect only as a consequence of the long-tenn change of the intensity of the vertical mixture of the atmosphere in the measured locality. Our obtained average volume activity of the 222Rn in the surface layer of the atmosphere appears in the middle of the range of the volume activities of 222Rn measured in the atmosphere in the other parts of the world. Furthermore there was showed that the effective dose rates from radon in the outdoor atmosphere may change during a day as well as during a year almost by factor of 2. The lowest effective dose rates by radon were found out during a day in the afternoon hours and the highest ones in the early morning hours. During a year the highest effective dose rates by radon were occurred in the winter months and the lowest ones in spring, the most often in April. (authors)

  12. 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.

  13. Engineering verification of the biomass production chamber

    Science.gov (United States)

    Prince, R. P.; Knott, W. M., III; Sager, J. C.; Jones, J. D.

    1992-01-01

    The requirements for life support systems, both biological and physical-chemical, for long-term human attended space missions are under serious study throughout NASA. The KSC 'breadboard' project has focused on biomass production using higher plants for atmospheric regeneration and food production in a special biomass production chamber. This chamber is designed to provide information on food crop growth rate, contaminants in the chamber that alter plant growth requirements for atmospheric regeneration, carbon dioxide consumption, oxygen production, and water utilization. The shape and size, mass, and energy requirements in relation to the overall integrity of the biomass production chamber are under constant study.

  14. Kinetics of atmospheric corrosion of mild steel, zinc, galvanized iron and aluminium at 10 exposure stations in India

    International Nuclear Information System (INIS)

    As a part of updating Corrosion Map of India project, atmospheric corrosion behaviour of commercially available engineering materials such as mild steel, galvanized iron, zinc and aluminium metals was studied in marine, industrial, urban, and rural environments by weight loss method at 10 exposure stations in India over a period of 5 years. The results of these studies demonstrated that galvanized iron, zinc and aluminium metals were several times more durable than mild steel. Compared to galvanized iron and zinc, aluminium provided superior protection in industrial and marine environment except at Mormugao Port Trust (MPT). It also offered much better resistance to corrosion in rural environments. At certain places, galvanized iron proved to be more durable than aluminium. The results obeyed well with the empirical kinetics equation of the form C = Kt n, where K and C are the corrosion losses in μm after 1 and 't' years of the exposure, respectively, and 'n' is a constant. Based on 'n' values, the corrosion mechanisms of these metals are predicted. The corrosion products formed on the metal samples in Chennai marine atmosphere were identified by X-ray diffraction analysis

  15. The exposure assessment of Rn-222 gas in the atmosphere(II)

    International Nuclear Information System (INIS)

    Dose assessment to inhalation exposure of indoor 222Rn daughters in 12 residential areas in Korea has been performed by long term averaged radon concentrations measured with passive CR-39 radon cups. A simple mathematical lung dosimetry model based on the ICRP-30 was derived to estimate the indoor radon daughters exposure. The long term average indoor 222Rn concentrations and corresponding equilibrium equivalent radon concentrations (EECRn) in 12 areas showed a range of 33.82 ∼ 61.42 Bq.m-3 (median : 48.90 Bq.m-3) and of 13.53 ∼ 24.57 Bq.m-3 (median: 19.55 Bq.m-3), respectively. Reference dose conversion functions for evaluation of regional lung dose and effective dose equivalent for unit exposure to EECRn have been derived for an adult. The effective dose equivalent conversion factor was estimated to be 1.07 x 10-5 mSv/Bq.h.m-3 and this conversion factor agreed well with that recommended by the ICRP and UNSCEAR report. The annual average dose equivalents(H) to Tracheo-Bronchial and Pulmonary region of the lung, and total lung from exposure to measured EECRn were estimated to be 17.52 mSv.y-l, 3.35 mSv.y-l and 20.90 mSv.y-1, respectively, and the resulting effective dose equivalent(HE) was estimated to be 1.25 mSv.y-l, which is almost 50% of the natural radiation exposure of 2.40 mSv.y-l reported by the UNSCEAR. (Author)

  16. GALVANIC CORROSION AND PROTECTION OF GECM/LY12CZ COUPLES UNDER DIFFERENT ATMOSPHERIC EXPOSURE CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    F.Lu; Q.P.Zhong; 等

    2003-01-01

    Galvanic compatibility between graphite epoxy composite materials (GECM) and LY12CZ aluminum alloy was evaluated in different atmospheric corrosion environ-ments and by laboratory electrochemical measurements.Open circuit potential elec-trochemical measurements showed a relatively large potemtial difference about 1 volt between the GECM and LY12CZ aluminum alloy,and this difference provided the driving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode. Having been exposed for 1,3or 5years in Beijing,Tuandao and Wanning station,GECM/LY12CZ couples showed significant losses of strength and elongation.Protec-tive coatings and non-conductive barriers breaking the galvanic corrosion circuit were evaluated under the same atmospheric corrosive conditions.Epoxy primer paint,glass cloth barriers and LY12CZ anodizing were effective in glvanic corrosion control for GECM/LY12CZ couples.

  17. GALVANIC CORROSION AND PROTECTION OF GECM/LY12CZ COUPLES UNDER DIFFERENT ATMOSPHERIC EXPOSURE CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    F. Lu; Q.P. Zhong; C.X. Cao

    2003-01-01

    Galvanic compatibility between graphite epoxy composite materials (GECM) andLY12CZ aluminum alloy was evaluated in different atmospheric corrosion environ-ments and by laboratory electrochemical measurements. Open circuit potential elec-trochemical measurements showed a relatively large potential difference about 1 voltbetween the GECM and LY12CZ aluminum alloy, and this difference provided thedriving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode.Having been exposed for 1, 3 or 5 years in Beijing, Tuandao and Wanning station,GECM/L Y12CZ couples showed significant losses of strength and elongation. Protec-tive coatings and non-conductive barriers breaking the galvanic corrosion circuit wereevaluated under the same atmospheric corrosive conditions. Epoxy primer paint, glasscloth barriers and LY12CZ anodizing were effective in galvanic corrosion control forGECM/L Y12CZ couples.

  18. Atmospheric corrosion of hot and cold rolled carbon steel under field exposure in Saudi Arabia

    International Nuclear Information System (INIS)

    Carbon steel (hot and cold rolled) specimens have been exposed to the action of different atmospheres at 20 test sites distributed in Saudi Arabia and was investigated in terms of environmental factors such as average temperature, average relative humidity and deposition rates of atmospheric pollutants (Cl- and SO2). Applying the standard ISO 9223 norm aggressiveness of the atmospheres corresponding to 0the different test sites has been determined. Calculations of corrosion rates were made via loss of weight and characterization of the corrosion products formed on samples has been carried out by means of X-ray diffraction (XRD). The major constituent of the rust formed in marine and marine-industrial environment is goethite (α-FeOOH). These samples also show the presence of a large proportion of lepidocrocite (γ-FeOOH) and small amounts of ferrihydrite and maghemite (γ-Fe2O3). In the case of urban and rural samples goethite is the major constituent of corrosion layers. The rust formed under the urban environment also contains large amounts of ferrihydrite and in a lesser proportion, of goethite and maghemite

  19. Chamber transport

    Energy Technology Data Exchange (ETDEWEB)

    OLSON,CRAIG L.

    2000-05-17

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

  20. Vectorization of nuclear codes for atmospheric transport and exposure calculation of radioactive materials

    International Nuclear Information System (INIS)

    Three computer codes MATHEW, ADPIC of LLNL and GAMPUL of JAERI for prediction of wind field, concentration and external exposure rate of airborne radioactive materials are vectorized and the results are presented. Using the continuous equation of incompressible flow as a constraint, the MATHEW calculates the three dimensional wind field by a variational method. Using the particle-in -cell method, the ADPIC calculates the advection and diffusion of radioactive materials in three dimensional wind field and terrain, and gives the concentration of the materials in each cell of the domain. The GAMPUL calculates the external exposure rate assuming Gaussian plume type distribution of concentration. The vectorized code MATHEW attained 7.8 times speedup by a vector processor FACOM230-75 APU. The ADPIC and GAMPUL are estimated to attain 1.5 and 4 times speedup respectively on CRAY-1 type vector processor. (author)

  1. Prediction of fire smoke exposure and air quality degradation: toward a high resolution coupled fire-atmosphere model

    Science.gov (United States)

    Mari, Céline; Strada, Susanna; Filippi, Jean-Baptiste; Bosseur, Frederic; Pialat, Xavier; Humberto Amorin, Jorge; Borrego, Carlos; Freitas, Saulo; Longo, Karla; Martins, Vera; Miranda, Ana Isabel; Monteiro, Alexandra; Paugam, Ronan

    2013-04-01

    Wildfires release significant amounts of trace gas and aerosols into the atmosphere. Firefighters are exposed to wildland fire smoke with adverse health effects. At larger scale, depending on meteorological conditions and fire characteristics, fire emissions can efficiently reduce air quality and visibility, even far away from emission sources. Uncertainties in fire emissions and fire plume dynamics are two important factors which substantially limit the capability of current models to predict smoke exposure and air quality degradation. A collaborative effort recently started in France to develop a coupled fire-atmosphere model based on the fire propagation model ForeFire, developed at the University of Corsica, and the mesoscale non-hydrostatic meteorological model Meso-NH, developed by the University of Toulouse and Meteo-France. ForeFire is a semi-physical model based on an analytical estimation of the rate of spread and an integration with a front tracking method. The fire model is used to provide gridded heating, water vapor and chemical fluxes at high temporal and spatial resolutions to Meso-NH. The coupled model was used in two configurations depending on the spatial resolution: with or without the feedback of the atmosphere on the fire propagation. At kilometric resolution, the model is used off-line to simulate two Mediterranean fires: an arson wildfire that burned in 2005 near Lancon-de-Provence, south-eastern France, and a well documented episode of the Lisbon 2003 fires (in collaboration with the University of Aveiro, Portugal). The question of the injection height is treated with an adaptation of the eddy-diffusivity/mass flux approach for convective boundary layer and compared to the 1D Plume Rise Model (developed at INPE) in contrasted meteorological scenarios. At higher resolution, the two-way coupled model is tested on idealized and real fire cases including ozone chemistry. Future required developments on surface emissions and combustion chemistry

  2. Pollution level, inhalation exposure and lung cancer risk of ambient atmospheric polycyclic aromatic hydrocarbons (PAHs) in Taiyuan, China

    International Nuclear Information System (INIS)

    Passive air samplers were deployed to collect both gas and particulate phase polycyclic aromatic hydrocarbons in Taiyuan between 2009 and 2010. Annual average concentrations of BaP equivalent concentration (B[a]Peq) in background, rural and urban areas were 2.90 ± 0.29, 23.2 ± 30.8 and 27.4 ± 28.1 ng/m3, respectively, with higher concentration in the winter than in other seasons. The median B[a]Peq concentrations of annual inhalation exposure were estimated to be in the range of 103–347 ng/d for all population groups in rural as well as in urban areas. The median values of incremental lifetime cancer risk (ILCR) induced by whole year inhalation exposure for all groups were basically larger than 10−6, with higher values in winter than in other seasons and in urban than in rural area. In the same season and area, the ILCR of adults was larger than other age groups and that of females was a little higher than males. - Highlights: ► The median values of ILCR were higher in winter than in other seasons. ► The median values of ILCR were higher in urban than in rural area. ► In the same season and area, the ILCR of adults was larger than other age groups. ► In the same season and area, the ILCR of females was a little higher than males. ► Exposure level and the cancer slope factor influenced the ILCR greatly. - The inhalation exposure and lung cancer risk of ambient atmospheric PAHs changed for different seasons, areas and population groups in Taiyuan, China.

  3. Studies of tracheo-bronchial mucus secretion and composition in the rat after exposure to the air pollutants SO sub 2 and NO sub 2 by means of the modified Ussing-chamber-technique. Untersuchungen der tracheobronchialen Schleimsekretion und -zusammensetzung am Rattenmodell nach Exposition gegenueber den inhalativen Noxen SO sub 2 und NO sub 2 mittels der modifizierten Ussing-Kammer-Technik

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, U.; Lauber, F.; Becker, R. (Marburg Univ. (Germany, F.R.). Medizinische Poliklinik)

    1990-04-01

    In order to determine the effects of short-time exposure to low concentrations of the air pollutants SO{sub 2} and NO{sub 2} on tracheal mucus secretion male Sprague-Dawley rats were exposed continuously to an atmosphere containing 10 ppm SO{sub 2} over a period of 6 days or 10 ppm NO{sub 2} over a period of 3 days respectively. Mucus secretion was then studied by means of Ussing-chambers, an in vitro method for tracheal organ culture. Thus tracheal preparations of treated and untreated animals were examined. One part of the study was done using {sup 35}S as radioactive precursor, the other by quantitative analysis of total protein and carbohydrate content of the secretions as the compounds of glycoproteins. Moreover light microscopic morphometric examination of the cultured tracheas was carried out. Neither short-time exposure to low concentrations of SO{sub 2} nor NO{sub 2} were seen to significantly affect mucus secretion. Only trends could be found. SO{sub 2} seemed to increase whereas NO{sub 2} seemed to reduce mucus secretion. By use of light microscopic morphometric studies no differences could be seen between exposed and untreated animals. The results are discussed with regard to the literature. (orig.).

  4. Accelerated atmospheric corrosion testing using a cyclic wet/dry exposure test

    International Nuclear Information System (INIS)

    Aluminum corrosion is important in overhead electrical conductors constructed from aluminum wire centrally reinforced by galvanized steel strands. Inspection of conductor after long service has implicated rubber bushing material, on the outside, and the galvanized strands, on the inside, as providing potential galvanic sites for the initiation of rapid aluminum corrosion. Therefore, the galvanic corrosion of aluminum in contact with graphite-loaded neoprene rubber, hot-dip galvanized steel and steel was assessed in a cyclic wet/dry exposure test using mixed-salts spray solutions containing appropriate ratios of sulfate and chloride ion. Aluminum was found to corrode at between 3 to 6 times its uncoupled rate when associated with the rubber material. While the eta-phase, relatively pure Zn, galvanized layer remained intact, galvanic corrosion of aluminum was slow. However, on exposure of the zeta-phase, Zn/Fe intermetallic layer, aluminum corroded about 35 times faster than expected in a solution with a high level of Cl- ion. The importance of these data to conductor lifetime is discussed

  5. 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...

  6. Vapor wall deposition in Teflon chambers

    OpenAIRE

    Zhang, X; R. H. Schwantes; R. C. McVay; H Lignell; M. M. Coggon; Flagan, R C; Seinfeld, J.H.

    2014-01-01

    Teflon chambers are ubiquitous in studies of atmospheric chemistry. Secondary organic aerosol (SOA) formation can be substantially underestimated owing to deposition of SOA-forming compounds to chamber walls. We present here an experimental protocol to constrain the nature of wall deposition of organic vapors in Teflon chambers. We measured the wall deposition rates of 25 oxidized organic compounds generated from the photooxidation of isoprene, toluene, α-pinene, and dodecan...

  7. Investigation of the influence of high humidity and exposure duration on the measurement results of radon concentration by means of PicoRad system in the CLOR calibration chamber

    International Nuclear Information System (INIS)

    PicoRad system based on activated charcoal collectors and liquid scintillation counter is one of the most popular passive methods of radon measurements which may be used both indoors and in other environments such as caves, tunnels, mines etc. It is well known that charcoal is also a very good adsorber of water vapor and it can reduce adsorption efficiency for radon. In PicoRad collectors, the charcoal is mixed with a dessicant to lower this effect. A series of expositions of PicoRad detectors was performed in a Central Laboratory for Radiological Protection (CLOR) radon calibration/climatic chamber to study the effect of high relative humidity on the airborne radon concentration measurements and the dependence of the results on the duration of exposure. The results obtained from the PicoRad system were referred to the mean concentrations delivered by an AlphaGUARD monitor, Genitron (GmbH), Germany. The main conclusions are the following: 1) the PicoRad system results are not affected by high relative humidity, including extreme values of 90-96%, for the duration of exposure up to ca. 24 h; 2) in the relative humidity range of 75-96% the correction coefficient linearly depends on the duration of exposure reaching a value of ca. 16 for 96 h exposure; 3) the PicoRad system delivers results corresponding better to the mean value of radon concentration in the last 6 h interval of exposure than that in the whole exposure duration. This finding is particularly important for the calibration of PicoRad collectors in the conditions of decreasing radon concentration due to radon decay. (author)

  8. Assessing effects of seasonal variation on occupational exposure of newsagent kiosks to polycyclic aromatic hydrocarbons found in the urban atmosphere of Tehran Metropolitan

    Directory of Open Access Journals (Sweden)

    F Rezaei

    2015-08-01

    Full Text Available Background and Objectives: PAHs are main components of urban air pollution and are mutagenic for human being. Seasonal variations have effects on the amount of exposure to PAHs. The objectives of this research were to determine the amount of newsagent’s exposure to PAHs found in the urban atmosphere of Tehran City during warm and cold periods and comparing exposure levels in two periods. Materials and Methods: The assessment of personal exposure was performed based on NIOSH method 5515 and was analyzed by gas chromatography–mass spectrometry (GC/MS. Mann- Whitney test was used to determine the effects of seasonal variation on the amount of newsagent’s exposure to PAHs. Results: The mean levels of newsagent’s exposure to benzo[a]pyrene in the south area of Tehran City were 0.148±0.010 and 0.417±0.041 μg/m3 in summer and autumn seasons respectively. The amount was higher than the mean levels of newsagent’s exposure in other geographic areas of city. The levels of newsagent’s exposure to all PAHs (p<0.001 were significantly higher in autumn compared with summer. Conclusion: The levels of exposure to PAHs during autumn were 2 to 3 fold higher than the levels of exposure during summer. Newsagents in the south area of Tehran City were experiencing higher levels of exposures to PAHs.

  9. Chamber Music's Lesson in Performing Confidence.

    Science.gov (United States)

    Stubbs, Darrel W.

    1983-01-01

    Chamber music has the advantage of offering the student maximum exposure as an individual performer. The absence of a conductor means that the student assumes the role of interpreter, thereby gaining musical maturity. For these reasons, curriculum hours should be more evenly divided between chamber music and larger ensembles. (CS)

  10. Exposures to the atmospheric ionizing radiation environment: a comparison between Icelandic and Italian civilian aviation flight personnel

    International Nuclear Information System (INIS)

    A comparative study has been performed between the radiation exposure patterns of the Icelandic and the Italian civilian aviation flight personnel. These two populations represent two extremes within the group of worldwide airline personnel. The Icelandic crew members, like only in the world their Canadian colleagues, always fly over or very close to the geomagnetic pole, and are this way exposed to high doses within each flight leg, whereas the Italian crew members, apart from transatlantic flights, are always flying close to the geomagnetic equator or anyhow quite far from the geomagnetic pole, receiving a small dose rates for each flight. For both Icelandic and Italian flights the actual radiation dose calculations along the various flight legs have been performed taking into account the different flight profiles for different routes and the variations over the considered time period of the heliocentric potential and of the geomagnetic field, in order to take into account the whole atmospheric neutron spectrum. Average dose rate values for aircraft types and routes have been obtained, along with their variations with time, and the different exposure patterns have been put into evidence. The annual individual dose for each crewmember is obtained by multiplying the average dose rates by the number of block hours for aircraft type flown each year. In the future it will be possible to analyze dose rates and cumulative doses to crew members in relation with different health outcomes for the two considered air crew groups. The data analysis in this respect is in progress, and the first exposure results are expected soon

  11. Optimum modellings of atmospheric diffusion of radioactive effluents and exposure doses in the accident consequence assessment (Level 3 PSA)

    International Nuclear Information System (INIS)

    Atmospheric diffusion and exposure strongly dependent on the environment were firstly considered in the full spectrum of accident consequence assessment to establish based on Korean conditions. An optimum weather category based on Korean climate and site-specific meteorology of Kori region was established by statistical analysis of measured data for 10 years. And a trajectory model was selected as the optimal one in the ACA by reviewing several existing diffusion models. Following aspects were considered in this selection as availability of meteorological data, ability to treat the change to wind direction, easy applicability of the model, and restriction of CPU time and core memory in current computers. Numerical integration method of our own was selected as the optimal dose assessment tool of external exposure. Unit dose rate was firstly computed with this method as the function of energy level of radionuclide, size of lattice, and distance between source and receptor, and then the results were rearranged as the data library for the rapid access to the ACA run. Dynamic ecosystem modelling has been done in order to estimate the seasonal variation of radioactivity for the assessment of ingestion exposure, considering Korean ingestion behavior, agricultural practice and the transportation. There is a lot of uncertainty in a countermeasure model due to the assumed values of parameters such as fraction of population with different shielding factor and driving speed. A new countermeasure model was developed using the concept of fuzzy set theory, since it provided the mathematical tools which could characterize the uncertainty involved in countermeasure modelling. (Author)

  12. Description of the SAFRAN Model for Evaluation of Public Exposure Resulting from Accidental Release of Airborne Radioactive Materials into the Atmosphere and User’s Guide. Annex II

    International Nuclear Information System (INIS)

    This document describes the method used in the SAFRAN tool for calculation of exposure arising from accidental release of airborne radioactive materials into the atmosphere. Model can be used for evaluation of public exposure to allow comparison with the relevant dose limiting criteria. The model is based on the public exposure evaluation concept as described in IAEA reports. While both these reports in primary addresses impacts arising from routine (e.g. long time permanent) releases, the concept employed can be adapted for assessment of impacts arising from accidental (e.g. short time) releases. Another source which has also been extensively used is the German Incident calculation bases

  13. 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...

  14. 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.

  15. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    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.

  16. 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.

  17. Time-resolved dosimetric verification of respiratory-gated radiotherapy exposures using a high-resolution 2D ionisation chamber array

    Science.gov (United States)

    King, R. B.; Agnew, C. E.; O’Connell, B. F.; Prise, K. M.; Hounsell, A. R.; McGarry, C. K.

    2016-08-01

    The aim of this work was to track and verify the delivery of respiratory-gated irradiations, performed with three versions of TrueBeam linac, using a novel phantom arrangement that combined the OCTAVIUS® SRS 1000 array with a moving platform. The platform was programmed to generate sinusoidal motion of the array. This motion was tracked using the real-time position management (RPM) system and four amplitude gating options were employed to interrupt MV beam delivery when the platform was not located within set limits. Time-resolved spatial information extracted from analysis of x-ray fluences measured by the array was compared to the programmed motion of the platform and to the trace recorded by the RPM system during the delivery of the x-ray field. Temporal data recorded by the phantom and the RPM system were validated against trajectory log files, recorded by the linac during the irradiation, as well as oscilloscope waveforms recorded from the linac target signal. Gamma analysis was employed to compare time-integrated 2D x-ray dose fluences with theoretical fluences derived from the probability density function for each of the gating settings applied, where gamma criteria of 2%/2 mm, 1%/1 mm and 0.5%/0.5 mm were used to evaluate the limitations of the RPM system. Excellent agreement was observed in the analysis of spatial information extracted from the SRS 1000 array measurements. Comparisons of the average platform position with the expected position indicated absolute deviations of  90% when criteria of 0.5%/0.5 mm were used. Results using this novel phantom arrangement indicate that the RPM system is capable of accurately gating x-ray exposure during the delivery of a fixed-field treatment beam.

  18. Time-resolved dosimetric verification of respiratory-gated radiotherapy exposures using a high-resolution 2D ionisation chamber array

    Science.gov (United States)

    King, R. B.; Agnew, C. E.; O’Connell, B. F.; Prise, K. M.; Hounsell, A. R.; McGarry, C. K.

    2016-08-01

    The aim of this work was to track and verify the delivery of respiratory-gated irradiations, performed with three versions of TrueBeam linac, using a novel phantom arrangement that combined the OCTAVIUS® SRS 1000 array with a moving platform. The platform was programmed to generate sinusoidal motion of the array. This motion was tracked using the real-time position management (RPM) system and four amplitude gating options were employed to interrupt MV beam delivery when the platform was not located within set limits. Time-resolved spatial information extracted from analysis of x-ray fluences measured by the array was compared to the programmed motion of the platform and to the trace recorded by the RPM system during the delivery of the x-ray field. Temporal data recorded by the phantom and the RPM system were validated against trajectory log files, recorded by the linac during the irradiation, as well as oscilloscope waveforms recorded from the linac target signal. Gamma analysis was employed to compare time-integrated 2D x-ray dose fluences with theoretical fluences derived from the probability density function for each of the gating settings applied, where gamma criteria of 2%/2 mm, 1%/1 mm and 0.5%/0.5 mm were used to evaluate the limitations of the RPM system. Excellent agreement was observed in the analysis of spatial information extracted from the SRS 1000 array measurements. Comparisons of the average platform position with the expected position indicated absolute deviations of  rates using gamma criteria of 2%/2 mm and 50% of the fluences achieved pass-rates  >90% when criteria of 0.5%/0.5 mm were used. Results using this novel phantom arrangement indicate that the RPM system is capable of accurately gating x-ray exposure during the delivery of a fixed-field treatment beam.

  19. Traffic-related atmospheric pollutants levels during pregnancy and offspring's term birth weight: a study relying on a land-use regression exposure model.

    OpenAIRE

    Slama, Rémy; Morgenstern, Verena; Cyrys, Josef; Zutavern, Anne; Herbarth, Olf; Wichmann, Heinz-Erich; Heinrich, Joachim; Study Group, Lisa

    2007-01-01

    International audience BACKGROUND: Some studies have suggested that particulate matter (PM) levels during pregnancy may be associated with birth weight. Road traffic is a major source of fine PM (PM with aero-dynamic diameter < 2.5 microm; PM(2.5)). OBJECTIVE: We determined to characterize the influence of maternal exposure to atmospheric pollutants due to road traffic and urban activities on offspring term birth weight. METHODS: Women from a birth cohort [the LISA (Influences of Lifestyle...

  20. Bulky PAH-DNA induced by exposure of a co-culture model of human alveolar macrophages and embryonic epithelial cells to atmospheric particulate pollution

    International Nuclear Information System (INIS)

    Because of their deep penetration in human lungs, fine airborne particulate matter were described as mainly responsible for the deleterious effects of exposure to air pollution on health. Organic constituents are adsorbed on particles surface and, after inhalation, some (polycyclic aromatic hydrocarbons, PAHs) can be activated into reactive metabolites and can bind to DNA. The formation of bulky DNA adducts has been researched after exposure of mono-and co-cultures of alveolar macrophages (AM) and human embryonic human lung epithelial (L132), to fine air pollution particulate matter Air samples have been collected with cascade impactor and characterized: size distribution (92.15% 2/g), inorganic (Fe, AI, Ca, Na, K, Mg, Pb, etc.) and organic compounds (PAHs, etc.). 32P post-labeling method was applied to detect bulky DNA adducts in AM and L132, in mono-and co-cultures, 72 h after their exposure to atmospheric particles at their Lethals and Effects concentrations or (LC or CE) to 50% (i.e. MA: EC50 = 74.63 μg/mL and L132: LC-5-0 = 75.36 μg/mL). Exposure to desorbed particles (MA: C1= 61.11 μg/mL and L132 : C2 = 61.71 μg/mL) and B[a]P (1 μM) were included. Bulky PAH-DNA adducts were detected in AM in mono-culture after exposure to total particles (Pt), to B[a]P and desorbed particles (Pd). Whatever the exposure, no DNA adduct was detected in L132 in mono-culture. These results are coherent with the enzymatic activities of cytochrome P450 l Al in AM and L132. Exposure of co-culture to Pt, or Pd induced bulky adducts to DNA in AM but not in L132. Exposure to B[a]P alone has altered the DNA of AM and L132, in co-culture. Exposure to Pt is closer to the environmental conditions, but conferred an exposure to amounts of genotoxic agents compared to studies using organic extracts. The formation of bulky DNA adducts was nevertheless observed in AM exposed to Pt, in mono- or co-culture, indicating that they were competent in terms of metabolic activation of PAHs. The DNA

  1. Pressurized ionization chamber detectors for industrial use

    International Nuclear Information System (INIS)

    The measurement of the thickness of the sheets made of different materials, e.g. metal, plastic, paper, cellulose, rubber, etc., is one of many industrial applications of nuclear techniques. The ionizing radiation detectors of ionization chamber type are based on measuring the variations in either exposure rate (for gamma radiation) or absorbed dose rate (for beta radiation) occurring in materials of different thickness, placed between the radiation source and the detector. The variations in exposure rate and absorbed dose rate can be traced by using radiation detectors of the ionization chamber type, which convert the exposure rate, X point, or the absorbed dose rate, D point, into a proportional electric current. The more stable the ionization current of the chambers (keeping a constant exposure rate or absorbed dose rate), the slighter the variations that can be detected in either exposure rate or absorbed dose rate, hence in the absorbing material placed between the radiation source and the detector. Based on these facts, several variants of such detectors, including the ionization chamber CIS-P5M-100Kr, CIS-P2M-1000Kr and CIS-P8M-70Kr, have been made. (author)

  2. 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.

  3. 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.

  4. 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

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

    OpenAIRE

    S. Pervez; A. Koshle; Y. Pervez

    2010-01-01

    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 a...

  6. Evaluation of submarine atmospheres: effects of carbon monoxide, carbon dioxide and oxygen on general toxicology, neurobehavioral performance, reproduction and development in rats. I. Subacute exposures.

    Science.gov (United States)

    Hardt, Daniel J; James, R Arden; Gut, Chester P; McInturf, Shawn M; Sweeney, Lisa M; Erickson, Richard P; Gargas, Michael L

    2015-02-01

    The inhalation toxicity of submarine contaminants is of concern to ensure the health of men and women aboard submarines during operational deployments. Due to a lack of adequate prior studies, potential general, neurobehavioral, reproductive and developmental toxicity was evaluated in male and female rats exposed to mixtures of three critical submarine atmospheric components: carbon monoxide (CO) and carbon dioxide (CO2; levels elevated above ambient), and oxygen (O2; levels decreased below ambient). In a 14-day, 23 h/day, whole-body inhalation study of exposure to clean air (0.4 ppm CO, 0.1% CO2 and 20.6% O2), low-dose, mid-dose and high-dose gas mixtures (high dose of 88.4 ppm CO, 2.5% CO2 and 15.0% O2), no adverse effects on survival, body weight or histopathology were observed. Reproductive, developmental and neurobehavioral performance were evaluated after a 28-day exposure in similar atmospheres. No adverse effects on estrus phase, mating, gestation or parturition were observed. No developmental or functional deficits were observed in either exposed parents or offspring related to motor activity, exploratory behavior or higher-level cognitive functions (learning and memory). Only minimal effects were discovered in parent-offspring emotionality tests. While statistically significant increases in hematological parameters were observed in the offspring of exposed parents compared to controls, these parameters remained within normal clinical ranges for blood cells and components and were not considered adverse. In summary, subacute exposures to elevated concentrations of the submarine atmosphere gases did not affect the ability of rats to reproduce and did not appear to have any significant adverse health effects. PMID:25600219

  7. Proportional chamber application to ionization measurements

    International Nuclear Information System (INIS)

    The possibility is investigated to use a proportional chamber measuring ionization particle losses in developing a detector capable of tracking the simultaneous passage of several particles against the background of a large number of single particles. The chamber used, with a 100x100 mm2 working plane, has three high-voltage electrodes and two signal planes spaced at 6 mm. The operating gas is argon + methylal (C3H8O2) at atmospheric pressure. The calculations made with consideration for the resolution obtained in the chamber, i.e., approximately 20% (5.9 keV) indicate that by using four chamber clearances it is possible to obtain the tracking efficiency of three particles over 99%

  8. Chamber catalogues of optical and fluorescent signatures distinguish bioaerosol classes

    Science.gov (United States)

    Hernandez, Mark; Perring, Anne E.; McCabe, Kevin; Kok, Greg; Granger, Gary; Baumgardner, Darrel

    2016-07-01

    Rapid bioaerosol characterization has immediate applications in the military, environmental and public health sectors. Recent technological advances have facilitated single-particle detection of fluorescent aerosol in near real time; this leverages controlled ultraviolet exposures with single or multiple wavelengths, followed by the characterization of associated fluorescence. This type of ultraviolet induced fluorescence has been used to detect airborne microorganisms and their fragments in laboratory studies, and it has been extended to field studies that implicate bioaerosol to compose a substantial fraction of supermicron atmospheric particles. To enhance the information yield that new-generation fluorescence instruments can provide, we report the compilation of a referential aerobiological catalogue including more than 50 pure cultures of common airborne bacteria, fungi and pollens, recovered at water activity equilibrium in a mesoscale chamber (1 m3). This catalogue juxtaposes intrinsic optical properties and select bandwidths of fluorescence emissions, which manifest to clearly distinguish between major classes of airborne microbes and pollens.

  9. BEBC bubble chamber

    CERN Multimedia

    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.

  10. High resolution drift chambers

    International Nuclear Information System (INIS)

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

  11. The Microstructure Stability of Atmospheric Plasma-Sprayed MnCo2O4 Coating Under Dual-Atmosphere (H2/Air) Exposure

    Science.gov (United States)

    Hu, Ying-Zhen; Li, Cheng-Xin; Zhang, Shan-Lin; Yang, Guan-Jun; Luo, Xiao-Tao; Li, Chang-Jiu

    2016-01-01

    Based on the specific structure of tubular solid oxide fuel cells, good chemical, microstructural, and phase stabilities for the protective coating are required in both the oxidizing and reducing environments. In this work, MnCo2O4 coatings were deposited onto porous Ni50Cr50-Al2O3 substrate by atmospheric plasma spray. The coated samples were tested at 800 °C with the coating exposed in air environment and the substrate in H2 environment. Reducing and pre-oxidizing treatments were performed prior to the stability test. The microstructural stability, phase composition, and electrical properties of the tested coatings were investigated. The surface morphology exhibited an excellent surface stability, and no obvious crystal coarsening was observed. With enhancement of the testing duration, the area-specific resistance presented a decreasing trend attributed to increase in the contact interface and densification of the upper layer. The cross-section views presented a dense upper layer and a relatively porous bottom layer. The x-ray diffraction results also indicated a single MnCo2O4 phase in the upper layer exposed to air environment and a reduced phase structure in the bottom layer from the substrate side. The evolution mechanism between the oxidation frontier and the reduction interface was then discussed.

  12. 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. PMID:25046852

  13. 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)

  14. Atmospheric Corrosion of Painted Galvanized and 55%Al-Zn Steel Sheets: Results of 12 Years of Exposure

    OpenAIRE

    C.I. Elsner; P. R. Seré; Di Sarli, A. R.

    2012-01-01

    Zinc or 55%Al-Zn alloy-coated steel sheets, either bare or covered by different painting systems, have been exposed for 12 years to the action of the urban atmosphere at the CIDEPINT station located in La Plata (34° 50′ South, 57° 53′, West), province of Buenos Aires, Argentina. The samples exposed surface was evaluated through periodical visual inspections, standardized adhesion tests, and electrochemical impedance measurements. The ambient variables monitored were average annual rains and t...

  15. Atmospheric constituents and surface-level UVB: implications for a paleoaltimetry proxy and attempts to reconstruct UV exposure during volcanic episodes

    CERN Document Server

    Thomas, Brian C; Dalton, Sean M

    2016-01-01

    Chemical and morphological features of spores and pollens have been linked to changes in solar ultraviolet radiation (specifically UVB, 280-315 nm) at Earth's surface. Variation in UVB exposure as inferred from these features has been suggested as a proxy for paleoaltitude. While UVB irradiance does increase with altitude above sea level, a number of other factors affect the irradiance at any given place and time. In this modeling study we use the TUV atmospheric radiative transfer model to investigate dependence of surface-level UVB irradiance and relative biological impact on a number of constituents in Earth's atmosphere that are variable over long and short time periods. We consider changes in O3 column density, and SO2 and sulfate aerosols due to periods of volcanic activity, including that associated with the formation of the Siberian Traps. We find that UVB irradiance may be highly variable under volcanic conditions and variations in several of these atmospheric constituents can easily mimic or overwhe...

  16. OPAL Jet Chamber Prototype

    CERN Multimedia

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

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

    Directory of Open Access Journals (Sweden)

    S. Pervez

    2010-06-01

    Full Text Available 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

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

    Directory of Open Access Journals (Sweden)

    S. Pervez

    2010-01-01

    Full Text Available 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

  19. New Ion-Nucleation Mechanism Relevant for the Earth's Atmosphere

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Svensmark, Henrik; Pedersen, Jens Olaf Pepke;

    An experiment has been set up in order to investigate the role of ionization in Earth's climate. We have chosen to start our investigation at the smallest scales, namely by studying the effect of cosmic ray produced ions on atmospheric aerosol nucleation and growth processes. This experiment...... is conducted at the Danish National Space Center, Center for Sun-Climate Research. It comprises a 7 m3 reaction chamber where atmospheric conditions can be simulated. The number of ions can be increased by exposure to radioactive sources and decreased by applying an electric field; this will enable experiments...

  20. Gridded ionization chamber

    International Nuclear Information System (INIS)

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

  1. 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.

  2. Toxic Test Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Hazardous material test facility Both facilities have 16,000 cubic foot chambers, equipped with 5000 CFM CBR filter systems with an air change...

  3. Calorimetry with flash chambers

    International Nuclear Information System (INIS)

    The flash chambers used in the Fermilab E594 neutrino experiment are described, and their use in a calorimeter discussed. Resolutions obtained with a calibration beam are presented, and comments made about the pattern recognition capabilities of the calorimeter

  4. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

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

  5. Gridded Ionization Chamber

    International Nuclear Information System (INIS)

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

  6. Influence of various parameters on the calculation of the population exposure due to discharge of radioactive matter into the atmosphere

    International Nuclear Information System (INIS)

    The evaluation of the influences of the examined parameters on the calculation of the dose rate shows that a new concept for determination of the radiation exposure in the surroundings of nuclear facilities is required. A computing formalism based on theoretical considerations determines the effective activity absorbed and, after combination with dose rate factors, the effective dose rate per year. It is of great importance to verify the validity of the still incomplete input data for determination of the dose factors of the age groups 'infants' and 'children' and to prepare new data records. (DG)

  7. 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.

  8. A study of external exposure variation due to atmospheric dispersion of 41Ar Plume in Bhabha Atomic Research Centre Trombay site

    International Nuclear Information System (INIS)

    Measurement of the ambient radiation level in the surroundings of any nuclear facility is necessary to ensure the regulation and control over the environmental releases and any possible radiological impact. This is achieved in Bhabha Atomic Research Centre Trombay site using various monitoring methodologies, different Dose Logging Equipments including Radiation Early Warning System and other passive devices. During the present study (October 2009 to September 2010), external exposures due to atmospheric dispersion of 41Ar, released from Cirus and Dhruva reactors (maximum cumulative release rate 8.27E+8 Bq.s-1) were assessed by installing Gamma tracers and TLDs at different monitoring locations. TLDs were used for the measurement of cumulative environmental doses for a longer period and Gamma tracer is primarily used for dose rate measurement with provision of dose assessment of any desired period

  9. On the capability of in-situ exposure in an environmental scanning electron microscope for investigating the atmospheric corrosion of magnesium.

    Science.gov (United States)

    Esmaily, M; Mortazavi, N; Shahabi-Navid, M; Svensson, J E; Johansson, L G; Halvarsson, M

    2015-06-01

    The feasibility of environmental scanning electron microscope (ESEM) in studying the atmospheric corrosion behavior of 99.97% Mg was investigated. For reference, ex-situ exposure was performed. A model system was designed by spraying few salt particles on the metal surface and further promoting the corrosion process using platinum (Pt) deposition in the form of 1×1×1 µm(3) dots around the salt particles to create strong artificial cathodic sites. The results showed that the electron beam play a significant role in the corrosion process of scanned regions. This was attributed to the irradiation damage occurring on the metal surface during the ESEM in-situ experiment. After achieving to a reliable process route, in a successful attempt, the morphology and composition of the corrosion products formed in-situ in the ESEM were in agreement with those of the sample exposed ex-situ. PMID:25731810

  10. 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.

  11. Performance of 1,000 and 1800 CFM HEPA filters on long exposure to low atmospheric dust loadings

    International Nuclear Information System (INIS)

    Comparative tests are in progress to determine the performance characteristics of European-design HEPA filters compared to US-design units made with the same filter paper. European filters are being operated at their rated capacity of 1,800 cfm and at 1,000 cfm. The US-design unit is operated at 1,000 cfm. Filters, installed on the roof of a 15-story building, are continuously exposed to an atmospheric dust aerosol of low concentration and small particle size. Plans are to continue these tests over a period of two or more years. Early results confirm that 1,800 cfm rated filters will have a very slow rate of pressure increase when operated at 1,000 cfm and an extended service life

  12. Whole-body nanoparticle aerosol inhalation exposures.

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L; Stapleton, Phoebe A; Minarchick, Valerie C; Nurkiewicz, Timothy R

    2013-01-01

    time (minute). The chamber pressure, temperature, relative humidity (RH), O2 and CO2 concentrations were monitored and controlled continuously. Nano-TiO2 aerosols collected on Nuclepore filters were analyzed with a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. In summary, we report that the nano-particle aerosols generated and delivered to our exposure chamber have: 1) steady mass concentration; 2) homogenous composition free of contaminants; 3) stable particle size distributions with a count-median aerodynamic diameter of 157 nm during aerosol generation. This system reliably and repeatedly creates test atmospheres that simulate occupational, environmental or domestic ENM aerosol exposures. PMID:23685643

  13. Atmospheric corrosion of brass in outdoor applications: patina evolution, metal release and aesthetic appearance at urban exposure conditions.

    Science.gov (United States)

    Goidanich, S; Brunk, J; Herting, G; Arenas, M A; Odnevall Wallinder, I

    2011-12-15

    Short (days, weeks) and long-term (months, years) non-sheltered field exposures of brass (15, and 20 wt.% Zn) and copper sheet have been conducted in three European cities (Milan, Stockholm, Madrid) to generate an in-depth time-dependent understanding of patina evolution, corrosion rates, aesthetic appearance, metal release and degree of dezincification in relation to detailed bulk and surface characteristics prior to exposure. This has been accomplished by using a multitude of surface and bulk analytical tools, chemical analysis and colorimetric investigations. Small differences in surface finish and local variations in nobility observed for the non-exposed brass alloys resulted in slight differences in corrosion initiation. Despite different kinetic behaviour and relative surface distributions of zinc- and copper-rich patina constituents, similar phases were identified with copper-rich phases rapidly dominating the outermost patina layer in Milan, compared to Madrid and Stockholm showing both copper- and zinc-rich phases. As a consequence of differences in surface coverage of copper- and zinc-rich corrosion products at the different sites, the release ratios of copper to zinc varied concordantly. The released amount of zinc to copper (Zn/Cu) was for both alloys and test sites always higher compared to the bulk composition showing a preferential release of zinc. The amount of released copper from the brass alloys was on an average 30-40% lower compared to copper sheet at all test sites investigated. Significantly lower annual total release rates of copper and zinc compared with annual corrosion rates were evident for both brass alloys at all sites. PMID:22051551

  14. 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.

  15. Outgassing rate of preconditioned vacuum systems after short exposure to the atmosphere: Outgassing rate measurements on Viton-A and copper

    International Nuclear Information System (INIS)

    When the sorption and desorption rates depend primarily on the diffusion of water vapor and atmospheric gases through the bulk of the sorbent (which may be an elastomer or plastic) and the process is reversible, then by an application of Fick's law and Duhamel's theorem equations can be derived for the outgassing rate as a function of time during subsequent pumpdowns in terms of the time of exposure to atmosphere with known relative humidity and the outgassing rate as a function of time during the initial conditioning cycle. Good agreement with the predictions of these equations has been obtained from measurements of repeated pumpdowns of a large-area sample of a Viton-A elastomer. However, similar experiments on copper plates showed relatively poor agreement with the theoretical equations indicating that the sorption--desorption process for water vapor in the oxide layer on metal surfaces may not be exactly reversible or that the process is not strictly controlled by diffusion. copyright 1995 American Vacuum Society

  16. The KLOE drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, M.; Aloisio, A.; Ambrosino, F.; Andryakov, A.; Antonelli, A.; Antonelli, M.; Anulli, F.; Bacci, C.; Bankamp, A.; Barbiellini, G.; Bellini, F.; Bencivenni, G.; Bertolucci, S.; 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. De; Robertis, G. De; Sangro, R. De; Simone, P. De; Zorzi, G. De; Dell' Agnello, S.; Denig, A.; Domenico, A. Di; Donato, C. Di; Falco, S. Di; 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.; Hagel, U.V.; 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, C.S.; Martemianov, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moalem, A.; Moccia, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nedosekin, A.; Panareo, M.; Pacciani, L.; Pages, P.; Palutan, M.; Paoluzi, L.; Pasqualucci, E.; Passalacqua, L.; Passaseo, M.; Passeri, A.; Patera, V.; Petrolo, E.; Petrucci, G.; 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. E-mail: paolo.valente@lnf.infn.it; Valeriani, B.; Venanzoni, G.; Veneziano, S.; Wu, Y.; Xie, Y.G.; Zhao, P.P.; Zhou, Y

    2001-04-01

    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.

  17. The KLOE drift chamber

    International Nuclear Information System (INIS)

    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 KL 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 cm2 in size in the 12 innermost layers and 3x3 cm2 in the outer ones. Details of the chamber design, calibration procedure and tracking performances are presented

  18. Seasonal response of photosynthetic electron transport and energy dissipation in the eighth year of exposure to elevated atmospheric CO2 (FACE) in Pinus taeda (loblolly pine)

    International Nuclear Information System (INIS)

    This study investigated the biological adaptation of loblolly pine following long-term seasonal exposure to elevated carbon dioxide (CO2) partial pressures (pCO2). Exposure to elevated atmospheric CO2 (pCO2) usually results in significant stimulation in light-saturated rates of photosynthetic CO2 assimilation. Plants are protected against photoinhibition by biochemical processes known as photoprotection, including energy dissipation, which converts excess absorbed light energy into heat. This study was conducted in the eighth year of exposure to elevated pCO2 at the Duke FACE site. The effect of elevated pCO2 on electron transport and energy dissipation in the pine trees was examined by coupling the analyses of the capacity for photosynthetic oxygen (O2) evolution, chlorophyll fluorescence emission and photosynthetic pigment composition with measurements of net photosynthetic CO2 assimilation (Asat). During the summer growing season, Asat was 50 per cent higher in current-year needles and 24 per cent higher in year-old needles in elevated pCO2 in comparison with needles of the same age cohort in ambient pCO2. Thus, older needles exhibited greater photosynthetic down-regulation than younger needles in elevated pCO2. In the winter, Asat was not significantly affected by growth pCO2. Asat was lower in winter than in summer. Growth at elevated pCO2 had no significant effect on the capacity for photosynthetic oxygen evolution, photosystem 2 efficiencies, chlorophyll content or the size and conversion state of the xanthophyll cycle, regardless of season or needle age. There was no evidence that photosynthetic electron transport or photoprotective energy dissipation responded to compensate for the effects of elevated pCO2 on Calvin cycle activity. 73 refs., 4 figs

  19. Toxicity of prolonged exposure to ethanol and gasoline autoengine exhaust gases

    Energy Technology Data Exchange (ETDEWEB)

    Massad, E.; Saldiva, P.H.; Saldiva, C.D.; Caldeira, M.P.; Cardoso, L.M.; de Morais, A.M.; Calheiros, D.F.; da Silva, R.; Boehm, G.M.

    1986-08-01

    A comparative chronic inhalation exposure study was performed to investigate the potential health effects of gasoline and ethanol engine exhaust fumes. Test atmospheres of gasoline and ethanol exhaust were given to Wistar rats and Balb C mice housed in inhalation chambers for a period of 5 weeks. Gas concentration and physical parameters were continually monitored during the exposure period. Several biological parameters were assessed after the exposure including pulmonary function, mutagenicity, and hematological, biochemical, and morphological examinations. The results demonstrated that the chronic toxicity of the gasoline-fueled engine is significantly higher than that of the ethanol engine.

  20. Wire chamber conference

    International Nuclear Information System (INIS)

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

  1. 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.

  2. 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.

  3. Drift chamber detectors

    International Nuclear Information System (INIS)

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

  4. LEP vacuum chamber, prototype

    CERN Multimedia

    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.

  5. 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.)

  6. 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.

  7. The iron component of particulate matter is antiapoptotic: A clue to the development of lung cancer after exposure to atmospheric pollutants?

    Science.gov (United States)

    Lovera-Leroux, Melanie; Crobeddu, Belinda; Kassis, Nadim; Petit, Patrice X; Janel, Nathalie; Baeza-Squiban, Armelle; Andreau, Karine

    2015-11-01

    The classification of outdoor air pollution as carcinogenic for humans strengthens the increasing concern about particulate matter (PM). We previously demonstrated that PM exposure produces an antiapoptotic effect resulting from polycyclic aromatic hydrocarbons (PAH) and water-soluble components. In this study, we investigated transition metallic compounds, particularly iron, in order to decipher their underlying molecular mechanisms that prevent apoptosis. Human bronchial epithelial cells were exposed for 4 h to different PM samples with established antiapoptotic effect (e.g. PM-AW) or not (e.g. PM-VS) or to their metallic components (Fe, Mn, Zn and Al) before apoptosis induction by the calcium ionophore A23187 or Staurosporine. PM-AW, Fe, Mn and Al significantly reduced induced apoptosis. The antiapoptotic effect of Fe was enhanced by benzo(a)pyrene, a typical PAH compound, but was totally reversed by the iron chelator, deferiprone. Furthermore, particles and iron triggered cellular ROS generation and prevented the depletion in glutathione levels observed during A23187-induced apoptosis. In contrast to benzo(a)pyrene, PM-AW and Fe rapidly activated NRF2, subsequently upregulated several target genes (HO1, NQO1 and GPX1) and modulated some genes which control cell death (BCL2, BAX and p53). The key role of the NRF2 pathway in the antiapoptotic effect mediated by Fe and PM was demonstrated using siRNA technology. Our results suggest that the iron component participates in the antiapoptotic effect of PM by activating a NRF2-dependent antioxidant process. As resisting to cell death is one of the hallmarks of cancer cells, these findings provide additional clues for understanding the development of lung cancer after atmospheric pollution exposure. PMID:26419736

  8. Three chamber negative ion source

    International Nuclear Information System (INIS)

    A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential

  9. The emulsion chamber technology experiment

    Science.gov (United States)

    Gregory, John C.

    1992-01-01

    Photographic emulsion has the unique property of recording tracks of ionizing particles with a spatial precision of 1 micron, while also being capable of deployment over detector areas of square meters or 10's of square meters. Detectors are passive, their cost to fly in Space is a fraction of that of instruments of similar collecting. A major problem in their continued use has been the labor intensiveness of data retrieval by traditional microscope methods. Two factors changing the acceptability of emulsion technology in space are the astronomical costs of flying large electronic instruments such as ionization calorimeters in Space, and the power and low cost of computers, a small revolution in the laboratory microscope data-taking. Our group at UAH made measurements of the high energy composition and spectra of cosmic rays. The Marshall group has also specialized in space radiation dosimetry. Ionization calorimeters, using alternating layers of lead and photographic emulsion, to measure particle energies up to 10(exp 15) eV were developed. Ten balloon flights were performed with them. No such calorimeters have ever flown in orbit. In the ECT program, a small emulsion chamber was developed and will be flown on the Shuttle mission OAST-2 to resolve the principal technological questions concerning space exposures. These include assessments of: (1) pre-flight and orbital exposure to background radiation, including both self-shielding and secondary particle generation; the practical limit to exposure time in space can then be determined; (2) dynamics of stack to optimize design for launch and weightlessness; and (3) thermal and vacuum constraints on emulsion performance. All these effects are cumulative and affect our ability to perform scientific measurements but cannot be adequately predicted by available methods.

  10. Scintillations in ionization chambers

    International Nuclear Information System (INIS)

    High purity Ar and mixtures of Ar with 1% CH4, 3% CH4, CO2 and N2, respectively, have been applied for fission fragment detection in a gridded ionization chamber. Gas scintillation has been observed simultaneously with a photomultiplier VALVO-XP 2041. Whereas all mixtures work equally well as an ionization gas, only Ar + 3% N2 shows a primary scintillation yield sufficient for fas timing. (orig.)

  11. Double chambered right ventricle

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-12-15

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

  12. Imploded test-chamber for an ISR intersection

    CERN Multimedia

    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.

  13. 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.

  14. Wire chambers revisited

    International Nuclear Information System (INIS)

    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. A 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 only clinical detector have been developed for positron emission tomography, where thin lead or lead-glass can provide an acceptable convertor for 511 keV photons. Two MWPC positron cameras have been evaluated clinically and one is now routine use in clinical oncology. The problems of detection efficiency have not been solved by these detectors although reliability and large-area PET imaging have been proven. (orig./HSI)

  15. Review of wire chamber aging

    International Nuclear Information System (INIS)

    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

  16. 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.

  17. 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...

  18. Cardiac chamber scintiscanning

    International Nuclear Information System (INIS)

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

  19. Comparative evaluation of nose-only vs. whole-body inhalation exposures for rats

    International Nuclear Information System (INIS)

    Two types of rat exposure chambers, nose-only and whole-body chambers, were evaluated simultaneously for the temporal and spatial distribution of the same test aerosols within the chambers, both with and without animals present. Results indicated that both types of exposure chambers performed well, with coefficients of variation less than 10% for both temporal and spatial variations. (author)

  20. 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.

    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......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...

  1. Neutron measurements with miniature fission chambers

    International Nuclear Information System (INIS)

    This report analyses the use and qualification of miniature fission chambers for two types of neutron measurements: 1) relative measurements in nuclear power reactors, or nuclear irradiation reactors. We consider the problem of burnable fissile material in detectors, under important neutron exposures and conclude on recommending the use of regenerating neutron detectors. 2) Measurements of integral physical parameters in experimental reactors. This method has been applied to measurements of fission rates in detectors with strong alpha-rays emitter deposits in order to establish standard tables of physical parameters. It has been used in particular for detectors including very radioactive actinium series. After a discussion of the instrumentation choice and data processing, specific to each measurements, we provide results on: 1) the technological and neutron behaviour of regenerating miniature fission chambers, in the swimming pool reactor 'TRITON', under a neutron exposure of 7.1020 n cm-2 and a gamma-rays exposure of 1,5.1011 rads about. The fissile material is 235U and the fertile material 234U. 2) The integral measurements of effective cross sections for 241Am and 238Pu in the experimental reactor 'MINERVE' use for study of problems of fast neutron reactors

  2. 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

  3. Multi-chamber ionization detector

    International Nuclear Information System (INIS)

    For the detector a single beta ionization source and a double- or three-chamber set-up is used, the chambers being designed in the shape of a truncated cone and facing each other with their bases. The source can be positioned with respect to the common center or modal electrode, the adjustment of the ionization in each chamber this becoming easier. The center or modal electrode also can be adjusted with respect to the source. (DG)

  4. A spark-chamber spectrometer

    International Nuclear Information System (INIS)

    A programme of developing techniques for the construction and use of spark chambers in high-energy physics experiments has been undertaken. Several methods of construction have been tested and found satisfactory. One method is to cement aluminium plates to frames made from glass or Plexiglas strips. Another is to place the aluminium plates in grooves machined in Plexiglas, forming a ''shelf'' design. A chamber made of rows of wires was successfully operated with a He-alcohol mixture. These chambers can either be filled with gas and sealed, or gas can be passed through them continuously. Chambers have been constructed with plates of various thicknesses ranging from 0.032 in downwards. The operation of the chambers with various spacings between the plates was also investigated. The performance of these chambers, when filled with several different gases (Ne, He, A) and with gas-alcohol mixtures, has been investigated. Several methods of applying high-voltage pulses to the chambers have been attempted. The results of these investigations are presented. Spark chambers placed in a magnetic field can be used in principle to determine the momentum of charged particles and if lead converter-plates are incorporated with them, the resulting system should serve as a gamma-ray spectrometer of high resolution and high efficiency. A magnet with an 18-in useful diameter and a 13000-G field is being fitted with spark chambers, whose performance will be tested with cosmic rays and with an accelerator beam. Results from such tests are presented. (author)

  5. Development of pulmonary oxygen toxicity in rats after hyperoxic exposure

    OpenAIRE

    Siermontowski Piotr; Pedrycz Agnieszka; Konarski Maciej; Kaczerska Dorota; Damme-Ostapowicz Katarzyna van; Olszański Romuald; Boratyński Zbigniew

    2014-01-01

    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 ani...

  6. Environmental test chamber

    Science.gov (United States)

    Qian, Li

    2016-04-01

    Increasing of particulates in the air in city became a serious problem , but in the Beijing area students rarely research such questions. The intelligent instrument of suspended particulate matter sampler which introduce from the institute of geology and geophysics, Chinese academy of sciences can be collected for all kinds of grain size of suspended matter in the air.We put them near schools,so the PM2.5 in the air near our shool can be collected. The method for analysis is the environmental magnetism, etc. Numerous studies have demonstrated rapid and non-destructive magnetic parameters measurement for rapid estimation of particulate sources of heavy metals and provides a very effective means. Environmental magnetism is a frontier science among earth science, environmental science and magnetism,which has been applied into many fields because it is capable of providing important information for studying the regional or global environmental changes and the impact of human activity on environment. Testing magnetic parameters of the particle can extract atmospheric particulate matter source, distribution, pollution level and dynamic change information. Measured the magnetic parameters of ARM, IRM, hysteresis loop , element composition, soil particle size of the soil, leaf, the river and dustfall samples and PM2.5 of the atmospheric dustfall samples on campus and the Beijing city.By means of environmental magnetism analysis of atmospheric pollutants category, amount, etc. Magnetic properties of pollutants may indicate the source of the pollutants, the nature of the analysis of pollutants, monitoring pollutant change over time.

  7. SONTRAC: A solar neutron track chamber detector

    Science.gov (United States)

    Jenkins, T. L.; Frye, G. M., Jr.; Owens, A.

    1985-01-01

    The recent detection on the solar maximum mission (SMM) satellite of high energy neutrons emitted during large solar flares has provided renewed incentive to design a neutron detector which has the sensitivity, energy resolution, and time resolution to measure the neutron time and energy spectra with sufficient precision to improve our understanding of the basic flare processes. Over the past two decades a variety of neutron detectors has been flown to measure the atmospheric neutron intensity above 10 MeV and to search for solar neutrons. The SONTRAC (Solar Neutron Track Chamber) detector, a new type of neutron detector which utilizes n-p scattering and has a sensitivity 1-3 orders of magnitude greater than previous instruments in the 20-200 MeV range is described. The energy resolution is 1% for neutron kinetic energy, T sub n 50 MeV. When used with a coded aperture mask at 50 m (as would be possible on the space station) an angular resolution of approx. 4 arc sec could be achieved, thereby locating the sites of high energy nuclear interactions with an angular precision comparable to the existing x-ray experiments on SMM. The scintillation chamber is investigated as a track chamber for high energy physics, either by using arrays of scintillating optical fibers or by optical imaging of particle trajectories in a block of scintillator.

  8. The impact of the site meteorological conditions, model and parameters of atmospheric dispersion on the assessment results of public radiation exposure under normal operation of nuclear facilities

    International Nuclear Information System (INIS)

    The real meteorological condition of the nuclear facilities located in different regions in China was used to do the comparative evaluation of the public radiation exposure from airborne effluent of a hypothetical 1000 MWe pressure water reactor (PWR) under the routine operation. The public radiation exposure is far less than the State Radiation Exposure Limit, because the airborne emission from the 1000 MWe PWR under the routine operation is very low. The site-meteorological condition, the dispersion model and its parameters have little influence on the public radiation exposure. Therefore it can simplify the assessment of the impact on environment of nuclear power station. (4 tabs., 4 figs.)

  9. 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

  10. National Ignition Facility Target Chamber

    International Nuclear Information System (INIS)

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

  11. Ion chamber based neutron detectors

    Science.gov (United States)

    Derzon, Mark S; Galambos, Paul C; Renzi, Ronald F

    2014-12-16

    A neutron detector with monolithically integrated readout circuitry, including: a bonded semiconductor die; an ion chamber formed in the bonded semiconductor die; a first electrode and a second electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; and the readout circuitry which is electrically coupled to the first and second electrodes. The bonded semiconductor die includes an etched semiconductor substrate bonded to an active semiconductor substrate. The readout circuitry is formed in a portion of the active semiconductor substrate. The ion chamber has a substantially planar first surface on which the first electrode is formed and a substantially planar second surface, parallel to the first surface, on which the second electrode is formed. The distance between the first electrode and the second electrode may be equal to or less than the 50% attenuation length for neutrons in the neutron absorbing material filling the ion chamber.

  12. DIFFUSION THEORY IMPROVES CHAMBER-BASED MEASUREMENTS OF TRACE GAS EMISSIONS

    Science.gov (United States)

    Chambers temporarily sealed to the soil surface are an important and for many purposes the only means of measuring trace gas emissions to the atmosphere. However, past interpretations of chamber data systematically underestimated actual emission rates in most applications because they ignored or poo...

  13. TRACE GAS EMISSIONS IN CHAMBERS: A NON-STEADY-STATE DIFFUSION MODEL

    Science.gov (United States)

    Non-steady-state (NSS) chambers are widely used to measure trace gas emissions from the Earth’s surface in the atmosphere. Unfortunately, traditional interpretations of time-dependent chamber concentrations often systematically underestimate predeployment exchange rates because they do not accuratel...

  14. Development of a Next-Generation Environmental Chamber Facility for Chemical Mechanism and VOC Reactivity Research

    OpenAIRE

    Carter, W P L; Fitz, D; D. R. Cocker III; Malkina, I L; Bumiller, K; Sauer, C G; Pisano, J T; Bufalino, C; Song, C.

    2005-01-01

    A new state-of-the-art indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosol (SOA) has been constructed and characterized. The chamber is designed for atmospheric chemical mechanism evaluation at low reactant concentrations under well-controlled environmental conditions. It consists of two collapsible 90 m3 FEP Teflon film reactors on pressure-controlled moveable frameworks inside a temperature-controlled e...

  15. Development of emanometer of normal atomosphere air mesh grid pulse lonization chamber

    International Nuclear Information System (INIS)

    Aiming at harmfulness of radon in the air, normal atmosphere air mesh grid pulse ionization chamber Emanometer has been developed, which can measure radon content in the air effectively. Emanometer is composed of normal atmosphere air mesh grid pulse ionization chamber, signal magnify and screen unit and MCU system. At signal magnify part, choosing high resistance and low noise field-effect tube amplified IC instead of field-effect transistor increases its interference immunity and stability significantly. (authors)

  16. 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.

  17. Cyclically controlled welding purge chamber

    Science.gov (United States)

    Gallagher, Robert L. (Inventor)

    1996-01-01

    An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

  18. Lifetime survivability of contaminated target-chamber optics

    International Nuclear Information System (INIS)

    Target chambers used for Inertial Confinement Fusion (ICF) expose laser optics to a very hostile environment, not only from high-fluence laser irradiation but also x-ray irradiation and particulate debris from targets and chamber wall materials. Expendable debris shields provide the first line of defense to more costly optics upstream in the laser beam path to contaminants generated within the target chamber. However, the replacement of a large number of debris shields is also an expensive proposition so that extending their usable lifetime within the chamber is important. We have conducted tests to show that optics can both be cleaned and damaged by laser irradiation at 355 nm after being contaminated with potential chamber-wall materials such as B4C and Al2O3. Such optics can survive from one to hundreds of laser shots, depending on degree of contamination and laser fluence levels. Similarly, we have studied the survivability of optics that have been exposed to direct contamination from representative target materials irradiated in the target chamber. We have also studied the effects on optics that were not directly exposed to targets, yet received secondary exposure from the above directly-exposed samples

  19. 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

  20. The HERMES Back Drift Chambers

    OpenAIRE

    al, S. Bernreuther et

    1998-01-01

    The tracking system of the HERMES spectrometer behind the bending magnet consists of two pairs of large planar 6-plane drift chambers. The design and performance of these chambers is described. This description comprises details on the mechanical and electronical design, information about the gas mixture used and its properties, results on alignment, calibration, resolution, and efficiencies, and a discussion of the experience gained through the first three years of operation.

  1. BEBC Big European Bubble Chamber

    CERN Multimedia

    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.

  2. Determination of the potential radiation exposure of the population close to the Asse II mine caused by deduction of radioactive substances with the discharge air in the normal operation using the ''Atmospheric Radionuclide-Transport-Model'' (ARTM)

    International Nuclear Information System (INIS)

    Between 1967 and 1978 125.787 packages filled with low-level and intermediate-level radioactive waste were emplaced in the mining plant Asse II. Volatile radioactive substances like H-3, C-14 and Rn-222 are released from the emplaced waste. These substances reach the ventilated parts of the mine and are released with the discharge air. The potential radiation exposure of the population caused by deduction of radioactive substances with the discharge air in the normal operation is determined by the ''Atmospheric Radionuclide-Transport-Model'' (ARTM). As result the maximal deductions of volatile radioactive substances with the discharge air in the normal operation of the Asse II mine lead to radiation exposure of the population, which is considerably lower than the permissible values of application rate.

  3. 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

  4. Air ionization wire plane chamber

    International Nuclear Information System (INIS)

    Radiation Measurement for protection level instrumentation requires large number of detectors. Since the number is large, the detector should be cost effective and yet should have good sensitivity. Gas detectors with presently available microelectronics and signal processing capabilities opened a new era in radiation monitoring. Present paper describes the use of air filled multi anode grid planes as detector for alpha detection. Due to multiple anode wire planes, the charge collection efficiency of the air ionization chamber is higher as compared to conventional ionization chamber. The signal from this Wire Plane Chamber (WPC) has a faster and narrower pulse shape as compared to conventional two-electrode chamber of similar dimensions. The reduction in capacitance also improves the signal to noise ratio so that air can be used as the ionization medium without any special cleaning procedure etc and it may be possible to use even engineering plastic as the structural material for the chamber. The paper gives the results obtained so far with this air ionization chamber. (author)

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

    International Nuclear Information System (INIS)

    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)

  6. 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.

  7. Whole-Body Nanoparticle Aerosol Inhalation Exposures

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T.; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L.; Stapleton, Phoebe A.; Minarchick, Valerie C.; Nurkiewicz, Timothy R.

    2013-01-01

    sampling flowrate (m3/min), and t is the sampling time (minute). The chamber pressure, temperature, relative humidity (RH), O2 and CO2 concentrations were monitored and controlled continuously. Nano-TiO2 aerosols collected on Nuclepore filters were analyzed with a scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. In summary, we report that the nano-particle aerosols generated and delivered to our exposure chamber have: 1) steady mass concentration; 2) homogenous composition free of contaminants; 3) stable particle size distributions with a count-median aerodynamic diameter of 157 nm during aerosol generation. This system reliably and repeatedly creates test atmospheres that simulate occupational, environmental or domestic ENM aerosol exposures. PMID:23685643

  8. LARGE VOLUME IONIZATION CHAMBER USED AS LABORATORY REFERENCE FOR LOW ENERGY X—RAY MEASUREMENT

    Institute of Scientific and Technical Information of China (English)

    杨国山; 薛永库; 等

    1994-01-01

    A large volume spherical ionization chamber of 195mm diameter and 0.36mg/cm2 wall thickness made from conducting carbon-fibre epoxy composite material has been developed.The mechanical intensity of the chamber is satisfactory for a good longterm volume stability.Owing to its large volume and thin wall,the chamber is sensitive to low energy photon beams and has excellent energy-response characteristics.This ionization chamber is suitable not only for a laboratory reference but also for measurement of low energy photon beam exposure rates at protection-level.

  9. Analysis of workstation: tritium atmospheric contamination

    International Nuclear Information System (INIS)

    Radioactive contamination, whether it is on the surface or in the atmosphere, could be the reason for individual internal exposure. The Practical Air Contamination Limit values enable the occupational health doctors as well as the 'Personne Competente en Radioprotection' (PCR: competent person in radioprotection) to pre-evaluate the risks resulting from atmospheric contamination. These values are used to determine the course of action regarding the workstation, but also as an optimisation tool for staff protection, within the framework of the application of the ALARA (As Low As Reasonably Achievable) principal. During the analysis of workstations, the PCRs at Pierre Fabre Laboratories were confronted with effective dose values which seemed to be, in their opinion, abnormally high. These values were in contradiction with the results of the urinary radio-toxicological exams, which are done within the framework of the reinforced medical monitoring of the technicians, and which have always been negative (whether the exams were done periodically or from time to time at the end of a radioactive experiment series). This is why it was considered relevant to rent bubble chamber systems, used for low-level concentrations of tritium and carbon-14. The measurements showed insignificant tritium atmospheric contamination levels in the laboratories, in particular for some experimental steps that were considered a priori problematic. This study, carried out within the framework of the workstation, enabled us to decrease the volatility factor value of tritiated compounds intervening in the effective dose calculation. (authors)

  10. Effect of Atmospheric Ions on Interfacial Water

    OpenAIRE

    Chien-Chang Kurt Kung; Pollack, Gerald H.

    2014-01-01

    The effect of atmospheric positivity on the electrical properties of interfacial water was explored. Interfacial, or exclusion zone (EZ) water was created in the standard way, next to a sheet of Nafion placed horizontally at the bottom of a water-filled chamber. Positive atmospheric ions were created from a high voltage source placed above the chamber. Electrical potential distribution in the interfacial water was measured using microelectrodes. We found that beyond a threshold, the positive ...

  11. Calculation of the electric field inside electret ionisation chambers - Influence on the response function

    International Nuclear Information System (INIS)

    The use of electret ion chambers for gamma dose and radon exposure measurement was increasing rapidly in the last years. In contrast to conventional ion chambers, the electric field in these detectors is not constant during the exposure time. Both field-strength and direction are changing due to inhomogeneous decrease of the electret surface charges. Data of numerical field calculations inside cylindrical electret Ionisation chambers are given. The change of the field-strength distribution with respect to electret discharge is described. The influence on the response function is discussed and experimentally verified. (author)

  12. Plasma chemistry in wire chambers

    International Nuclear Information System (INIS)

    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 55Fe 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

  13. Studies of Aldehydes in an Atmosphere Simulation Chamber

    OpenAIRE

    J. Bossmeyer

    2006-01-01

    Im Zuge dieser Arbeit wurde ein DOAS-Instrument an der Atmosphären-Simulationskammer SAPHIR (Forschungszentrum Jülich) aufgebaut, das auf einem Vielfach-Reflektionssystem des White-Designs basiert. Das DOAS-Instrument ermöglichte erstmalig den Nachweis von NO3 an der Kammer. Ein NO3- Verlustprozess wurde in der trockenen Kammer beobachtet und mit einer Lebensdauer von (42 +/- 4) min charakterisiert. Davon abgesehen diente die Kammer für Experimente von dreierlei Art. (1) Das DOAS konnte unter...

  14. The CLAS drift chamber system

    CERN Document Server

    Mestayer, M D; Asavapibhop, B; Barbosa, F J; Bonneau, P; Christo, S B; Dodge, G E; Dooling, T; Duncan, W S; Dytman, S A; Feuerbach, R; Gilfoyle, G P; Gyurjyan, V; Hicks, K H; Hicks, R S; Hyde-Wright, C E; Jacobs, G; Klein, A; Klein, F J; Kossov, M; Kuhn, S E; Magahiz, R A; Major, R W; Martin, C; McGuckin, T; McNabb, J; Miskimen, R A; Müller, J A; Niczyporuk, B B; O'Meara, J E; Qin, L M; Raue, B A; Robb, J; Roudot, F; Schumacher, R A; Tedeschi, D J; Thompson, R A; Tilles, D; Tuzel, W; Vansyoc, K; Vineyard, M F; Weinstein, L B; Wilkin, G R; Yegneswaran, A; Yun, J

    2000-01-01

    Experimental Hall B at Jefferson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic field of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a fixed target on the toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and efficiency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements.

  15. Particle detection with drift chambers

    CERN Document Server

    Blum, Walter; Rolandi, Luigi

    2008-01-01

    This volume presents a thorough introduction to the theory and operation of drift chambers, one of the most important modern methods of elementary particle detection. The topics, presented in a text-book style with many illustrations, include the basics of gas ionization, by particles and by lasers, drift of electrons and ions in gases and signal creation and discuss in depth the fundamental limits of accuracy and the issue of particle identification. The book also surveys all types of drift chambers and the various drift-chamber gases in use. The calculation of the device parameters and physical processes are presented in some detail, as is all necessary background material. Thus the treatment, well beyond addressing the specialist in the field, is well suited to graduate physics students and nuclear engineers seeking a both thorough and pedagogical introduction to the field. The second edition presents a completely revised, updated and expanded version of this classic text. In particular, significantly more...

  16. Tohoku one meter bubble chamber

    International Nuclear Information System (INIS)

    At the request of Tohoku University and the National Laboratory for High Energy Physics, IHI has developed a complete freon bubble chamber system successfully, which is used for photo analysis of elementary particles physics. This system will be delivered to Fermi National Accelerator Laboratory (FNAL) in Illinois (U.S.A.) and will be coupled with the superconducting accelerator (TEVATRON) for the study of elementary particles. The total system of the freon bubble chamber is composed of a stainless steel casting spherical bubble chamber with a diameter of about one meter, an expansion system for freon pressure control, hydraulic system for driving an expansion piston, a freon feed system, a temperature control system, an overall control system as well as camera and flashlight for photograph. (author)

  17. The CLAS drift chamber system

    Energy Technology Data Exchange (ETDEWEB)

    Mestayer, M.D.; Carman, D.S.; Asavaphibhop, B. [and others

    1999-04-01

    Experimental Hall B at Jefferson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic field of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a fixed target on a toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and efficiency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements.

  18. Impedances of Laminated Vacuum Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Burov, A.; Lebedev, V.; /Fermilab

    2011-06-22

    First publications on impedance of laminated vacuum chambers are related to early 70s: those are of S. C. Snowdon [1] and of A. G. Ruggiero [2]; fifteen years later, a revision paper of R. Gluckstern appeared [3]. All the publications were presented as Fermilab preprints, and there is no surprise in that: the Fermilab Booster has its laminated magnets open to the beam. Being in a reasonable mutual agreement, these publications were all devoted to the longitudinal impedance of round vacuum chambers. The transverse impedance and the flat geometry case were addressed in more recent paper of K. Y. Ng [4]. The latest calculations of A. Macridin et al. [5] revealed some disagreement with Ref. [4]; this fact stimulated us to get our own results on that matter. Longitudinal and transverse impendances are derived for round and flat laminated vacuum chambers. Results of this paper agree with Ref. [5].

  19. General purpose nuclear irradiation chamber

    International Nuclear Information System (INIS)

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

  20. The CLAS drift chamber system

    International Nuclear Information System (INIS)

    Experimental Hall B at Jefferson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic field of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a fixed target on the toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and efficiency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements

  1. 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 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 <5 years of age at diagnosis has been examined from ten cancer registries from three continents and both hemispheres, which include registration data from the early 1960s or before. No evidence of a markedly increased risk of leukaemia in young children following the peak of above-ground nuclear weapons testing, or that incidence rates are related to level of exposure to fallout, is apparent from these registration rates, providing strong grounds for discounting the idea that the risk of leukaemia in young children from (3)H or (14)C (or any other radionuclide present in both nuclear weapons testing fallout and discharges from nuclear installations) has been grossly underestimated and that such exposure can account for the findings of the KiKK Study. PMID:24477409

  2. The knife-edge chamber

    International Nuclear Information System (INIS)

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

  3. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

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

  4. Development of special ionization chambers for a quality control program in mammography

    International Nuclear Information System (INIS)

    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)

  5. Hypobaric chamber for wind sensor testing in Martian condictions

    OpenAIRE

    Kowalski, Lukasz; García Molina, Francisco Miguel

    2011-01-01

    In this paper we will describe the installation of a low pressure stainless steel horizontal chamber to be used in preliminary tests of a Mars atmosphere wind sensor. It includes custom made additional QF ports, electric and pneumatic interfaces together with a vacuum pump system. Absolute pressure, as a function of the pump operational time during the vacuum process and depressurization will be shown as a result of experimental measurements. We will propose the integration of a typical compa...

  6. Homogeneous Water Nucleation in a Laminar Flow Diffusion Chamber

    Czech Academy of Sciences Publication Activity Database

    Manka, A.; Brus, David; Hyvärinen, A.-P.; Lihavainen, H.; Wölk, J.; Strey, R.

    Prague : Orgit, 2009 - (Smolík, J.; O'Dowd, C.), s. 480-483 ISBN 978-80-02-12161-2. [International Conference Nucleation and Atmospheric Aerosols /18./. Prague (CZ), 10.08.2009-14.08.2009] Institutional research plan: CEZ:AV0Z40720504 Keywords : water * homogeneous nucleation * laminar flow diffusion chamber Subject RIV: CF - Physical ; Theoretical Chemistry http://www.icnaa.cz/

  7. Characterization and testing of a new environmental chamber

    Science.gov (United States)

    Leskinen, A.; Yli-Pirilä, P.; Kuuspalo, K.; Sippula, O.; Jalava, P.; Hirvonen, M.-R.; Jokiniemi, J.; Virtanen, A.; Komppula, M.; Lehtinen, K. E. J.

    2015-06-01

    A 29 m3 Teflon chamber, designed for studies on the aging of combustion aerosols, at the University of Eastern Finland is described and characterized. The chamber is part of a research facility, called Ilmari, where small-scale combustion devices, a dynamometer for vehicle exhaust studies, dilution systems, the chamber, and cell and animal exposure devices are located side by side under the same roof. The small surface-to-volume ratio of the chamber enables reasonably long experiment times, with particle wall loss rate constants of 0.088, 0.080, 0.045, and 0.040 h-1 for polydisperse, 50, 100, and 200 nm monodisperse aerosols, respectively. The NO2 photolysis rate can be adjusted from 0 to 0.62 min-1. The irradiance spectrum is centered at either 350 or 365 nm, and the maximum irradiance, produced by up to 160 blacklight lamps, is 29.7 W m-2, which corresponds to the ultraviolet (UV) irradiance in Central Finland at noon on a sunny day in the midsummer. The temperature inside the chamber is uniform and can be kept at 25±1 °C. The chamber is kept in an overpressure with a moving top frame, which reduces sample dilution and entrance of contamination during an experiment. The functionality of the chamber was tested with oxidation experiments of toluene, resulting in secondary organic aerosol (SOA) yields of 12-42%, depending on the initial conditions, such as NOx concentration and UV irradiation. The highest gaseous oxidation product yields of 12.4-19.5% and 5.8-19.5% were detected with ions corresponding to methyl glyoxal (m/z 73.029) and 4-oxo-2-pentenal (m/z 99.044), respectively. Overall, reasonable yields of SOA and gaseous reaction products, comparable to those obtained in other laboratories, were obtained.

  8. Photosynthesis and growth response of almond to increased atmospheric ozone partial pressures

    International Nuclear Information System (INIS)

    Uniform nursery stock of five almond cultivars [Prunus dulcis (Mill) D.A. Webb syn. P. amygdalus Batsch, cv. Butte, Carmel, Mission, Nonpareil, and Sonora] propagated on peach (P. domstica L. Batsch.) rootstock were exposed to three different atmospheric ozone (O3) partial pressures. The trees were planted in open-top fumigation chambers on 19 Apr. 1989 at the University of California Kearny Agricultural Center located in the San Joaquin Valley of California. Exposures of the trees to three atmospheric O3 partial pressures lasted from 1 June to 2 Nov. 1989. The mean 12-h [0800-2000 h Pacific Daylight Time (PDT)] O3 partial pressures measured in the open-top chambers during the experimental period were 0.038, 0.060, and 0.112 μPa Pa-1 O3 in the charcoal filtered, ambient, and ambient + O3 treatments, respectively. Leaf net CO2 assimilation, trunk cross-sectional area growth, and root, trunk, foliage, and total dry weight of Nonpareil were reduced by increased atmospheric O3 partial pressures. Mission was unaffected by O3 and Butte, Carmel, and Sonora were intermediate in their responses. Foliage of Nonpareil also abscised prematurely in the ambient and ambient + O3 treatments. The results indicate that there are almond cultivars that are sensitive to O3 exposure

  9. Effects of VOCs on herbaceous plants in an open-top chamber experiment

    International Nuclear Information System (INIS)

    Birdsfoot trefoil and broad-leaved dock were affected by VOCs. - A selection of herbaceous plants representing the ground flora around a typical chemical installation in the UK was exposed continuously for 7 weeks to a mixture of six VOCs (acetone, acetonitrile, dichloromethane, ethanol, methyl t-butyl ether and toluene) in open-top chambers. Exposure concentrations were based on predictions of atmospheric dispersion from a single source, at a distance of approximately 2 km. The effects of continuous exposure, representing a worst-case, were measured in terms of uncontrolled water loss from leaves, leaf wettability, chlorophyll content and fluorescence, dry matter production and detailed observations of changes in plant growth and phenology. There were significant effects of VOC exposure on seed production, leaf water content and photosynthetic efficiency in some plant species. Such effects may be detectable in vegetation close to major industrial point sources of VOCs, or as a result of an accidental release of material during manufacture or transport. Some of the species tested e.g. birdsfoot trefoil (Lotus corniculatus L.) seem to be promising as potential bioindicators for VOCs, but there may be other even more sensitive species waiting to be discovered. However, the most obvious and conveniently measured response to VOC exposure in the birdsfoot trefoil (premature senescence i.e. advanced timing of seed pod production) could easily be confused in the field with climatic influences. It is also uncertain at this stage whether any of the effects observed would lead to longer term ecological changes in natural plant communities, through biased competition between sensitive and more tolerant species

  10. Drift and proportional tracking chambers

    International Nuclear Information System (INIS)

    Many techniques have been exploited in constructing tracking chambers, particle detectors which measure the trajectories and momenta of charged particles. The particular features of high-energy interactions - charged particle multiplicities, angular correlations and complex vertex topologies, to name a few - and the experimental environment of the accelerator - event rates, background rates, and so on - accent the importance of certain detector characteristics. In high energy e+e-, anti pp and pp interactions the final states are dominated by closely collimated jets of high multiplicity, requiring good track-pair resolution in the tracking chamber. High energy particles deflect very little in limited magnetic field volumes, necessitating good spatial resolution for accurate momentum measurements. The colliding beam technique generally requires a device easily adapted to full solid-angle coverage, and the high event rates expected in some of these machines put a premium on good time resolution. Finally, the production and subsequent decays of the tau, charmed and beautiful mesons will provide multiple vertex topologies. To reconstruct these vertices reliably will require considerable improvements in spatial resolution and track-pair resolution. This lecture considers the proportional counter and its descendant, the drift chamber, as tracking chambers. Its goal is to review the physics of this device in order to understand its performance limitations and promises

  11. 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.

  12. The TESLA Time Projection Chamber

    OpenAIRE

    Ghodbane, Nabil

    2002-01-01

    A large Time Projection Chamber is proposed as part of the tracking system for a detector at the TESLA electron positron linear collider. Different ongoing R&D studies are reviewed, stressing progress made on a new type readout technique based on Micro-Pattern Gas Detectors.

  13. 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.

  14. A method for the long-term exposure of rabbits to environmental pollutant gases

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, G.J.; Page, C.P. (Dept. of Pharmacology, King' s College, University of London, London (United Kingdom)); Price, J.F. (Dept. of Thoracic Medicine, King' s College Hospital, London (United Kingdom))

    1994-08-01

    The aims of the present study were twofold. Firstly, we wanted to develop a system for the exposure of rabbits to pollutant gases that would monitor gas concentrations accurately, allow flexibility, be simple to operate, and could be constructed at relatively modest cost. Additionally, we wanted to determine whether the procedures necessary for the daily exposure of young rabbits had any detrimental effect on their development. Using the enviromental exposure system that we developed, littermate New Zealand White rabbits, neonatally immunized to either Alternaria tenuis or house dust mite antigen were exposed 2 h daily, from within 24 h of birth until 3 months of age, to either 4 ppm nitrogen dioxide (NO[sub 2]), or 5 ppm sulphur dioxide (SO[sub 2]) or ambient air. The environmental exposure system consists of four sections; a stainless steel exposure chamber; an airflow monitoring and control system and gas delivery system, a gas detector and monitoring system; and an exhaust fan. Equilibration and wash-out times of gas were short and the gas mixing within the chamber atmosphere was uniform. Levels of gases were reliably maintained throughout the period of exposure within predetermined limits. The weights of the immunized, gas-exposed animals did not differ significantly from those of the immunized, air-exposed animals at any time throughout the 3 month period of exposure. At 3 months of age, the basal values for lung resistance and dynamic compliance did not differ between gas- and air-exposed rabbits. These values did not differ significantly from those obtained from naive animals of the same age. Our results suggest that we have developed a sensitive, reliable and simple environmental exposure and monitoring system. It is anticipated that the methodology described will allow the careful investigation of the effects of long-term exposure to pollutant gases from birth on the development of airways hyperresponsiveness. (au)

  15. A method for the long-term exposure of rabbits to environmental pollutant gases.

    Science.gov (United States)

    Douglas, G J; Price, J F; Page, C P

    1994-08-01

    The aims of the present study were twofold. Firstly, we wanted to develop a system for the exposure of rabbits to pollutant gases that would monitor gas concentrations accurately, allow flexibility, be simple to operate, and could be constructed at relatively modest cost. Additionally, we wanted to determine whether the procedures necessary for the daily exposure of young rabbits had any detrimental effect on their development. Using the environmental exposure system that we developed, littermate New Zealand White rabbits, neonatally immunized to either Alternaria tenuis or house dust mite antigen were exposed 2 h daily, from within 24 h of birth until 3 months of age, to either 4 ppm nitrogen dioxide (NO2), or 5 ppm sulphur dioxide (SO2) or ambient air. The environmental exposure system consists of four sections; a stainless steel exposure chamber; an airflow monitoring and control system and gas delivery system; a gas detector and monitoring system; and an exhaust fan. Equilibration and wash-out times of gas were short and the gas mixing within the chamber atmosphere was uniform. Levels of gases were reliably maintained throughout the period of exposure within predetermined limits. The weights of the immunized, gas-exposed animals did not differ significantly from those of the immunized, air-exposed animals at any time throughout the 3 month period of exposure. At 3 months of age, the basal values for lung resistance and dynamic compliance did not differ between gas- and air-exposed rabbits. These values did not differ significantly from those obtained from naive animals of the same age. Our results suggest that we have developed a sensitive, reliable and simple environmental exposure and monitoring system. It is anticipated that the methodology described will allow the careful investigation of the effects of long-term exposure to pollutant gases from birth on the development of airways hyperresponsiveness. PMID:7957839

  16. A brief review of the use of environmental chambers for gas phase studies of kinetics, chemical mechanisms and characterisation of field instruments

    OpenAIRE

    Seakins P.W.

    2010-01-01

    This introductory review considers the role of environmental chambers in atmospheric chemistry, emphasising the importance of being able to carry out studies in controlled conditions. The advantages and disadvantages of different types of chambers are discussed and compared. Examples of the use of chambers for kinetic and mechanistic studies are presented. The final section of this brief review considers the use of chambers in providing a well defined environment for calibrating and investiga...

  17. A brief review of the use of environmental chambers for gas phase studies of kinetics, chemical mechanisms and characterisation of field instruments

    Directory of Open Access Journals (Sweden)

    Seakins P.W.

    2010-12-01

    Full Text Available This introductory review considers the role of environmental chambers in atmospheric chemistry, emphasising the importance of being able to carry out studies in controlled conditions. The advantages and disadvantages of different types of chambers are discussed and compared. Examples of the use of chambers for kinetic and mechanistic studies are presented. The final section of this brief review considers the use of chambers in providing a well defined environment for calibrating and investigating the performance of field instruments.

  18. Occupational exposure in hemodynamic

    International Nuclear Information System (INIS)

    This paper has an objective to perform a radiometric survey at a hemodynamic service. Besides, it was intended to evaluate the effective dose of health professionals and to provide data which can contribute with minimization of exposures during the realization of hemodynamic procedure. The radiometric survey was realized in the real environment of work simulating the conditions of a hemodynamic study with a ionization chamber

  19. Establishment of a radon test chamber

    International Nuclear Information System (INIS)

    A walk-in type radon test chamber of 23 m3 has been built for testing and calibration of radon measurement instruments. The environmental conditions of the test chamber can be varied within a wide range of values. The design objectives specification, monitoring instruments and testing results of this chamber are discussed. This test chamber is available for domestic radon researchers and its accuracy can be traced to the international standard. A routine intercomparison study will be held annually by using this chamber. Other tests like radon progeny and thoron standard may also be performed in this chamber. (1 fig.)

  20. 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......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  1. Chamber dynamic research with pulsed power

    Energy Technology Data Exchange (ETDEWEB)

    PETERSON,ROBERT R.; OLSON,CRAIG L.; RENK,TIMOTHY J.; ROCHAU,GARY E.; SWEENEY,MARY ANN

    2000-05-15

    In Inertial Fusion Energy (IFE), Target Chamber Dynamics (TCD) is an integral part of the target chamber design and performance. TCD includes target output deposition of target x-rays, ions and neutrons in target chamber gases and structures, vaporization and melting of target chamber materials, radiation-hydrodynamics in target chamber vapors and gases, and chamber conditions at the time of target and beam injections. Pulsed power provides a unique environment for IFE-TCD validation experiments in two important ways: they do not require the very clean conditions which lasers need and they currently provide large x-ray and ion energies.

  2. 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...

  3. 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......Responses of the mycorrhizal fungal community in terrestrial ecosystems to global change factors are not well understood. However, virtually all land plants form symbiotic associations with mycorrhizal fungi, with approximately 20% of the plants' net primary production transported down...... by mycorrhizal and other root-associated fungi to global change factors of all the fungal types studied could have broad implications for plant community structure and biogeochemistry of subarctic ecosystems....

  4. Carbon-14 transfer into potato plants following a short exposure to an atmospheric 14CO2 emission: observations and model predictions.

    Science.gov (United States)

    Melintescu, A; Galeriu, D; Tucker, S; Kennedy, P; Siclet, F; Yamamoto, K; Uchida, S

    2013-01-01

    To improve the understanding of the environmental (14)C behaviour, the International Atomic Energy Agency (IAEA) coordinated a Tritium and C-14 Working Group (T&C WG) in its EMRAS (Environmental Modelling for Radiation Safety) programme. One of the scenarios developed in the frame of T&C WG involved the prediction of time dependent (14)C concentrations in potato plants. The experimental data used in the scenario were obtained from a study in which potatoes (Solanum tuberosum cv. Romano) were exposed to atmospheric (14)CO(2) in a wind tunnel. The observations were used to test models that predict temporal changes in (14)C concentrations in leaves at each sampling time for each experiment and (14)C concentrations in tubers at the final harvest of each experiment. The experimental data on (14)C dynamics in leaves are poorly reproduced by most of the models, but the predicted concentrations in tubers are in good agreement with the observations. PMID:22995861

  5. Application of a tandem ionization chamber in a quality control program of X-ray beams, radiotherapy level

    International Nuclear Information System (INIS)

    A tandem ionization chamber, developed at the Instituto de Pesquisas Energeticas e Nucleares (IPEN), for X radiation beams, radiotherapy level, was applied into a quality control program of the Calibration Laboratory of IPEN. This ionization chamber is composed by two ionization chambers, with a volume of 0.6 cm3 each one. Its inner plane-parallel electrodes and guard rings are made of different materials: one is made of aluminum and the other is made of graphite. Because of this difference in materials, the ionization chamber forms a tandem system. The relative response of the calibration factors of both sides of the chamber allows an easy verification of the X-ray beam qualities stability. The ionization chamber was submitted to some tests to verify the stability of its response: leakage current before and after exposure, repeatability and reproducibility. The performance of the ionization chamber was satisfactory. (author)

  6. 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.

  7. LEP vacuum chamber, early prototype

    CERN Multimedia

    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).

  8. Actuator System with Dual Chambers

    DEFF Research Database (Denmark)

    2015-01-01

    (8), the lid having a shaft opening (17) for a shaft (6) coupled to the magnetic rotor (5), wherein the magnetic rotor (5), when inserted in the translator cylinder (2), is arranged to translate a linear movement of the translator cylinder (2) into a rotational movement of the magnetic rotor by using...... magnetic flux (82) interacting between the magnetic stator and the magnetic rotor, said rotational movements is being transferred through a shaft (6), the lid (8) with a shaft opening (17) arranged for receiving the shaft (6), wherein the shaft is arranged to make both the linear and the rotational...... movement in the shaft opening (17), the lid (8) being arranged for confining the second end (15) of the translator cylinder (2), the translator cylinder confined by the lid (8) forms,when divided by the magnetic rotor (5), a first chamber (TC) with a first volume and a second chamber(BC) with a second...

  9. 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

    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 by......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...

  10. Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers

    Science.gov (United States)

    Hao, Xiaoli; Guo, Chenxin; Lin, Yaolin; Wang, Haiqiao; Liu, Heqing

    2016-01-01

    Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS) model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers. PMID:27213422

  11. Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers.

    Science.gov (United States)

    Hao, Xiaoli; Guo, Chenxin; Lin, Yaolin; Wang, Haiqiao; Liu, Heqing

    2016-01-01

    Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS) model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers. PMID:27213422

  12. MPS II drift chamber system

    International Nuclear Information System (INIS)

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

  13. The KEK 1 m hydrogen bubble chamber

    International Nuclear Information System (INIS)

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

  14. 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......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  15. NRAO RF Anechoic Chamber & Antenna 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. 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. Effects of long-term elevated atmospheric CO2 concentrations on Pinus ponderosa

    International Nuclear Information System (INIS)

    This report details the results from an experiment of the effects of long-term elevated atmospheric CO2 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 CO2 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 CO2 responses should be intensified. Open-top chambers proved suitable for use in multiyear exposures of mature trees. With respect to the preliminary examination of CO2 responses, many interesting observations were made. The nature of the preliminary results suggests that future long-term field CO2 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 CO2 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

  18. Growing and analyzing biofilms in flow chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

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

  19. Ionization chamber kit for in core dosimetry

    International Nuclear Information System (INIS)

    Sensitivity of a set of ionization walled precise chambers, including chambers with a wall made of a material with different atomic number Z (from 6 to 92), is investigated. It is noted that the considered chambers differ by high radiation stability at slight leakage current on isolators. Using the chambers for determining effective energy of gamma-radiation of the stopped IRT-2000 reactor has shown a good agreement of measuring results with the calculation

  20. 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...

  1. LEP vacuum chamber cross-section

    CERN Multimedia

    1987-01-01

    This diagram shows the layout of the vacuum chambers used at LEP, which was in operation at CERN between 1989 and 2000. Vacuum chambers are necessary in accelerators to prevent unwanted interactions that can destabilise the beam. The pump on the right sucks air out of the chamber allowing the beam to progress with minimal interactions.

  2. Wire chamber degradation at the Argonne ZGS

    International Nuclear Information System (INIS)

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

  3. A cryogenic chamber for scattering measurements

    OpenAIRE

    Lopes, M. I.; Chepel, V.; Kuchenkov, A.; Gonçalves, O. D.; Schechter, H.

    1999-01-01

    We have constructed a cryogenic chamber to measure scattering cross sections of photons in liquids of low-boiling point. The chamber was tested with liquid xenon using a 137Cs radioactive source emitting 662 keV photons. The spectra obtained are presented and analyzed, attesting the good performance of the chamber for the desired purposes.

  4. Sensitivity of gaseous xenon ionisation chambers (1961)

    International Nuclear Information System (INIS)

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

  5. Cosmic test of honeycomb drift chambers

    International Nuclear Information System (INIS)

    The status of the test of pokalon-C honeycomb drift chambers by cosmic rays is presented. We discuss the cosmic track reconstruction, autocalibration of drift chambers and identification of cross-talk hits. Preliminary results of the test performed for drift chambers with 5 mm cells are given

  6. Subminiature fission chamber with gas tight penetration

    International Nuclear Information System (INIS)

    Fission chambers suffer from gas leaks at electric feed-trough. This micro chamber suppresses that defect thanks to an alumina plug and welded seal of the chamber sleeve. This device is easy to produce at industrial scale with reduced dimensions (1,5 mm diameter, 25 mm length). It can work with 30 m long feeding cables. (D.L.). 3 figs

  7. 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.)

  8. Simple Cloud Chambers Using Gel Ice Packs

    Science.gov (United States)

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

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

  9. 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.

  10. Accuracy evaluation of the prescribed calibration factors for ionisation chambers belonging to radiotherapy centres

    International Nuclear Information System (INIS)

    Air kerma and exposure calibration factors of 14 ionisation chambers belonging to ten local radiotherapy centres have been determined by SSDL in the recent last ten month (1/10/1998 - 31/7/1999). The results obtained were compared either with previous SSDL results, or the chambers certificate values. The range of the percentage deviations obtained was -1.70% to 1.18%, which lies between the IAEA accepted value of range ±3.5%. (author)

  11. 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.

  12. Atmospheric transformation of diesel emissions.

    Science.gov (United States)

    Zielinska, Barbara; Samy, Shar; McDonald, Jacob D; Seagrave, JeanClare

    2010-04-01

    (y)) were monitored using chemiluminescence and Fourier transform infrared instruments. At the end of the exposures, samples of particle-associated and semivolatile organic compounds (SVOCs) were collected from the chamber for chemical analysis using an XAD-coated annular denuder followed by a filter and XAD cartridge. (XAD is an adsorbent polystyrene divinylbenzene resin used in sampling cartridges.) Samples for toxicity testing were collected using Teflon filters followed by two XAD cartridges. The chemical analyses included determination of organic carbon (OC), elemental carbon (EC), carbon fractions, inorganic ions (e.g., sulfate and nitrate), and speciated organic compounds (polycyclic aromatic hydrocarbons [PAHs], nitro-PAHs, polar compounds, alkanes, hopanes, and steranes). The toxicity tests were performed with extracts of PM combined with the SVOCs. The biologic activity of these extracts was evaluated in vivo by instilling them into the tracheas of rodents and measuring pulmonary toxicity, inflammation, and oxidative-stress responses. Results from the chemical analyses indicated that aging DE in the dark with added NO3 radicals and aging DE in daylight with and without additions led to the formation of additional particles and SVOC mass caused by reactions of VOCs, SVOCs, and inorganic gases. The greatest increase in mass occurred with the addition of VOCs as co-reactants. The proportions of the pyrolized OC (POC) fraction increased in the organic mass, which suggested that highly polar and oligomeric compounds had been formed. Results from the toxicity testing were consistent with the hypothesis that the toxicity of the samples had been affected by changes in their composition (caused both by the atmospheric aging and by changes in the initial composition of the DE presumably associated with changes in the engine, which was new at the outset and accrued wear during the study). PMID:20572366

  13. Design and construction of a radiation monitor with ionization chamber

    International Nuclear Information System (INIS)

    The design and construction of a portable radiation monitor with ionization chamber for gamma and x rays measurements in the range from 40 KeV to 2 MeV are described in detail. The monitor is calibrated to give the exposure rate in Roentgens/hour in three linear ranges: 0-25 mR/h, 0-250 mR/h and 0-2500 mR/h for an ionization chamber with a sensitive volume of 600 cubic centimeters. Two conventional 9 V alkaline batteries are used to energize the monitor. The small current coming from the ionization chamber is measured by an operational amplifier with electrometer characteristics. The high voltage power supply to bias the chamber is made with a blocking oscillator and a ferrite transformer. Starting form a discussion of the desired characteristics of the monitor, the technical specifications are established. The design criteria for every section are shown. The testing procedures used to qualify every block and the results for three units are reported. (Author)

  14. 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.

  15. 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. PMID:25917777

  16. 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.

  17. 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.

  18. 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.

  19. Cylindrical ionization chamber on compressed krypton

    International Nuclear Information System (INIS)

    A cylindrical ionization chamber with a grid is described. The chamber is used in experiments to search for double positron decay and conversion of atom electron into positron in Kr78. The working substance of the chamber is krypton. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. Energy resolution is 2.1% for 1.84 MeV energy (the gamma quantum source is 88Y) when using the chamber filled with Kr+0.2%H2 mixture at pressure of 25 atm

  20. Ionization chambers for LET determination

    DEFF Research Database (Denmark)

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

    2010-01-01

    Modern radiotherapy facilities for cancer treatment such as the Heavy Ion Therapy Centre (HIT) in Heidelberg (Germany) enable sub millimetre precision in dose deposition. For the measurement of such dose distributions and  characterization of the particle beams, detectors with high spatial...... of columnar recombination was designed to model the detector efficiency of an ionization chamber. Here, we have shown that despite the approximations and simplification made, the theory is correct for the LETs typically found in clinical radiotherapy employing particles from protons to carbon ions...

  1. TRU waste characterization chamber gloveboxes

    International Nuclear Information System (INIS)

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

  2. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

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

  3. Experimental work on drift chambers

    International Nuclear Information System (INIS)

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

  4. 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...

  5. 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.

  6. Atmospheric contamination

    International Nuclear Information System (INIS)

    It is about the levels of contamination in center America, the population's perception on the problem, effects of the atmospheric contamination, effects in the environment, causes of the atmospheric contamination, possibilities to reduce the atmospheric contamination and list of Roeco Swisscontac in atmospheric contamination

  7. 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...

  8. Testing Plant Responses to Rarified Atmospheres for Inflatable Greenhouses

    Science.gov (United States)

    Corey, Kenneth A.

    2000-01-01

    Reduced atmospheric pressures will likely be used to minimize mass and engineering requirements for plant growth habitats used in extraterrestrial applications. A chamber with high vacuum capability was used to design and begin construction of a system for testing plant responses to reduced pressure atmospheres. Several preliminary tests were conducted to evaluate chamber suitability for plant tests and to determine performance of thermal and vacuum systems at ambient and reduced pressure atmospheres down to 0.1 atm. The first tests consisted of measurements of internal gas volume and leakage rate. The method for volume determination was quite sensitive and will be needed for plant gas exchange measurements and calculations. This information will also be used in conjunction with the leak rate. Measured leak rates on the order of 0.46 mm Hg/min at 76 mm Hg pressure are low enough to conduct sensitive carbon dioxide exchange rate measurements at reduced pressure given an adequate plant sample (0.5 to 1.0 sq m area). A test rack with lighting provided by three high-pressure sodium vapor lamps was built to accommodate both short-term and long-term plant responses. Initial short-term experiments with lettuce showed that a pressure of 77 mm Hg resulted in a 6.1-fold increase in the rate of water loss compared to water loss at ambient pressure. Plants were severely wilted after 30 minutes exposure to 77 mm Hg. Water loss was found to be inversely correlated with atmospheric pressure over the range of pressures from 0.2 to 1.0 atm; the rate of water loss at 0.2 atm was 4.3 times higher than water loss at ambient pressure. Older leaves showed moderate wilting during exposure to 156 mm Hg, but those exposed to 345 mm, Hg remained turgid. Results suggest a reduced atmospheric pressure limit of 0.2 to 0.3 atm for lettuce grown in a solid medium. Follow-up experiments with carbon dioxide control and control at high relative humidity (> 90 %) will be needed to further confirm

  9. 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)

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

    International Nuclear Information System (INIS)

    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 PIF2 and 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)

  11. 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.

  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. Picture chamber for radiographic system

    International Nuclear Information System (INIS)

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

  14. Legacies of the bubble chamber

    International Nuclear Information System (INIS)

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

  15. Repatriation of Gamma Chambers Exported by India

    International Nuclear Information System (INIS)

    The Board of Radiation and Isotope Technology (BRIT) is engaged in the production and supply of laboratory gamma chambers. The gamma chambers are self-shielded devices in which a number of 60Co source pencils placed in a cylindrical cage. The gamma chambers are type approved as a device and a transportation package separately by the Atomic Energy Regulatory Board. BRIT has exported number of such gamma chambers. For some of the gamma chambers, the type approval validity period is over and can no longer be transported. Hence, the radiation sources need to be transferred to a type approved package before transportation. BRIT has decommissioned five such gamma chambers so far and sources have been repatriated back to India. (author)

  16. Neutron-chamber detectors and applications

    International Nuclear Information System (INIS)

    Detector applications in Nuclear Safeguards and Waste Management have included measuring neutrons from fission and (alpha,n) reactions with well-moderated neutron proportional counters, often embedded in a slab of polyethylene. Other less-moderated geometries are useful for detecting both bare and moderated fission-source neutrons with good efficiency. The neutron chamber is an undermoderated detector design comprising a large, hollow, polyethylene-walled chamber containing one or more proportional counters. Neutron-chamber detectors are relatively inexpensive; can have large apertures, usually through a thin chamber wall; and offer very good detection efficiency per dollar. Neutron-chamber detectors have also been used for monitoring vehicles and for assaying large crates of transuranic waste. Our Monte Carlo calculations for a new application (monitoring low-density waste for concealed plutonium) illustrate the advantages of the hollow-chamber design for detecting moderated fission sources. 9 refs., 6 figs., 2 tabs

  17. Disinfection effect of non-thermal atmospheric pressure plasma for foodborne bacteria

    Science.gov (United States)

    Pervez, Mohammad Rasel; Inomata, Takanori; Ishijima, Tatsuo; Kakikawa, Makiko; Uesugi, Yoshihiko; Tanaka, Yasunori; Yano, Toshihiro; Miwa, Shoji; Noguchi, Akinori

    2015-09-01

    Non-thermal atmospheric pressure plasma (NAPP) exposure can be a suitable alternative for bacteria inactivation in food processing industry. Specimen placed in the enclosure are exposed to various reactive radicals produced within the discharge chamber. It is also exposed to the periodic variation of the electric field strength in the chamber. Dielectric barrier discharge is produced by high voltage pulse (Vpp = 18 kV, pulse width 20 μs, repetition frequency 10 kHz) in a polypropylene box (volume = 350 cm3) using helium as main feed gas. Inactivation efficiency of NAPP depends on the duration of NAPP exposure, applied voltage pulse strength and type, pulse duration, electrode separation and feed gas composition. In this study we have investigated inactivation of Bacillus lichenformis spore as an example of food borne bacteria. Keeping applied voltage, electrode configuration and total gas flow rate constant, spores are exposed to direct NAPP for different time duration while O2 concentration in the feed gas composition is varied. 10 minutes NAPP exposure resulted in ~ 3 log reduction of Bacillus lichenformis spores for 1% O2concentration (initial concentration ~ 106 / specimen). This work is supported by research and development promotion grant provided by the Hokuriku Industrial Advancement Center.

  18. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

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

  19. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    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).

  20. IFE Chamber Technology - Status and Future Challenges

    International Nuclear Information System (INIS)

    Significant progress has been made on addressing critical issues for inertial fusion energy (IFE) chambers for heavy-ion, laser and Z-pinch drivers. A variety of chamber concepts are being investigated including drywall (currently favored for laser IFE), wetted-wall (applicable to both laser and ion drivers), and thick-liquid-wall (favored by heavy ion and z-pinch drivers). Recent progress and remaining challenges in developing IFE chambers are reviewed

  1. Construction and performance of large flash chambers

    International Nuclear Information System (INIS)

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

  2. 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.

  3. Drift chamber tracking with neural networks

    International Nuclear Information System (INIS)

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

  4. 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.

  5. High rate tests of microstrip gas chambers for CMS

    CERN Document Server

    Malina, R F; Bell, B; Bellazzini, R; Bozzo, M; Brand, C; Brez, A; Caner, A; Cattai, A; Chorowicz, V; Contardo, D; Latronico, L; Lumb, N; Magazzù, C; Martín, J; Massai, M M; Mirabito, L; Morelli, A; Raffo, R; Rolandi, Luigi; Smadja, G; Spandre, G; Spezziga, M; Tsirou, A L

    1999-01-01

    Microstrip gas chambers (MSGC's) have been proposed for equipping the outer region of the tracker of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). The MSGC's have undergone extensive development and tests during the last few years and their performance is well established. An important issue that has to be addressed to date is whether MSGC's can maintain their characteristics after a long exposure to an intense flux of particles, similar to LHC. We report results from the most recent beam test addressing this topic. (9 refs).

  6. 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.

  7. The Mark II Vertex Drift Chamber

    International Nuclear Information System (INIS)

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 μm spatial resolution and 2 gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO2 mixtures are presented. 10 refs., 12 figs., 1 tab

  8. Cylindrical ionization chamber with compressed krypton

    International Nuclear Information System (INIS)

    A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78Kr. Krypton is the working gas material of the chamber. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. The energy resolution is 2.1% for an energy of 1.84 MeV (the source of γ-quanta is 88Y) when the chamber is filled with a mixture of Kr+0.2% H2 under a pressure of 25 atm

  9. D0 central tracking chamber performance studies

    International Nuclear Information System (INIS)

    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

  10. 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...

  11. D0 central tracking chamber performance studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, D.

    1991-12-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an 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} {yields} e {sup +} e{sup {minus}} events.

  12. 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...

  13. Review of Electret ion chamber technology for measuring technologically enhanced natural radioactivity

    International Nuclear Information System (INIS)

    Electret ion chamber (EIC) is a passive integrating ionization chamber used extensively for measuring technologically enhanced radioactivity. Commercially available electret ion chambers called 1E-PERM (Electret-Passive Environmental Radiation Monitors) electret ion chambers are relatively new and are in use only from the past 10 years. The EIC consists of a stable electret (electrically charged Teflon disc) mounted inside an electrically conducting chamber. The electret serves both as a source of the electric field and as a sensor. The ions produced inside the chamber are collected by the electret. The reduction in charge of the electret is related to total ionization during the period of exposure. This charge reduction is measured using a battery operated electret reader. Using appropriate calibration factors and the exposure time, the desired parameters such as radon concentration in air is calculated. These low cost monitors require neither power nor battery and several hundreds of these can be used simultaneously and serviced by one reader. These monitors do not provide on line readings, but provide an average value over a period of time. The EICs have been used for measuring: (a) indoor and outdoor radon, (b) thoron, (c) dissolved radon and radium in water, (d) environmental gamma, (e) radon emanating radon concentration in soil samples and in pipes, (f) radon flux from surfaces and building materials. The purpose of this paper is to describe these methods and give selected reference to the related publications for more detailed reading. (author)

  14. Re-evaluating the Frankfurt isothermal static diffusion chamber for ice nucleation

    OpenAIRE

    J. Schrod; A. Danielczok; Weber, D.; M. Ebert; Thomson, E. S.; H. G. Bingemer

    2015-01-01

    Recently significant advances have been made in the collection, detection, and characterization of ice nucleating particles (INP). Ice nuclei are particles that facilitate the heterogeneous formation of ice within the atmospheric aerosol by lowering the free energy barrier to spontaneous nucleation and growth of ice from atmospheric water and/or vapor. The Frankfurt isostatic diffusion chamber (FRIDGE) is an INP collection and offline detection system that has become widely deployed and sho...

  15. Re-evaluating the Frankfurt isothermal static diffusion chamber for ice nucleation

    OpenAIRE

    Schrod, Jann; Danielczok, Anja; Weber, Daniel; Ebert, Martin; Thomson, Erik S.; Bingemer, Heinz G.

    2016-01-01

    Recently significant advances have been made in the collection, detection and characterization of ice nucleating particles (INPs). Ice nuclei are particles that facilitate the heterogeneous formation of ice within the atmospheric aerosol by lowering the free energy barrier to spontaneous nucleation and growth of ice from atmospheric water and/or vapor. The Frankfurt isostatic diffusion chamber (FRankfurt Ice nucleation Deposition freezinG Experiment: FRIDGE) is an INP collecti...

  16. Oxidative potential of secondary organic aerosols produced from photooxidation of different hydrocarbons using outdoor chamber under ambient sunlight

    Science.gov (United States)

    Jiang, Huanhuan; Jang, Myoseon; Sabo-Attwood, Tara; Robinson, Sarah E.

    2016-04-01

    The oxidative potential of various secondary organic aerosols (SOA) was measured using dithiothreitol (DTT) assay to understand how organic aerosols react with cellular materials. SOA was produced via the photooxidation of four different hydrocarbons (toluene, 1,3,5-trimethylbenzene, isoprene and α-pinene) in the presence of NOx using a large outdoor photochemical smog chamber. The DTT consumption rate was normalized by the aerosol mass, which is expressed as DTTmass. Toluene SOA and isoprene SOA yielded higher DTTmass than 1,3,5-trimethylbenzene SOA or α-pinene SOA. In order to discover the correlation between the molecular structure and oxidative potential, the DTT responses of selected model compounds were also measured. Among them, conjugated aldehydes, quinones, and H2O2 showed considerable DTT response. To investigate the correlation between DTT response and cell responses in vitro, the expression of biological markers, i.e. IL-6, IL-8, and HMOX-1 were studied using small airway epithelial cells. Higher cellular expression of IL-8 was observed with toluene SOA exposure compared to 1,3,5-trimethylbenzene SOA exposure, which aligned with the results from DTT assay. Our study also suggests that within the urban atmosphere, the contribution of toluene SOA and isoprene SOA to the oxidative potential of ambient SOA will be more significant than that of α-pinene SOA.

  17. Indoor air pollution by organic emissions from textile floor coverings. Climate chamber studies under dynamic conditions

    Science.gov (United States)

    Sollinger, S.; Levsen, K.; Wünsch, G.

    The time dependence of the emission of organic compounds from a polyamide floor covering with styrene-butadiene-rubber (SBR) backing was studied in three climate chambers (0.03, 1.0 and 38 m 3) at 23°C 5nd 45% RH. While volatile compounds such as toluene reach a maximum concentration in the gas phase within 1 h and decrease in concentration to less than 2% within 60 h, the concentration of less volatile compounds, such as 4-phenylcyclohexene, decreases slowly over a period of months. If the chamber is well mixed and a defined chamber loading is maintained the observed concentrations do not depend on the chamber size, the wall material and air velocity. The concentration of the observed emissions is roughly proportional to the chamber loading. Surprisingly it is not inversely proportional to the air exchange rate. Rather, at high air exchange rates mass transfer from the carpet to the gas phase is enhanced. The "decreasing source models" of Dunn and Tichenor ( Atmospheric Environment22, 885-894, 1988) have been applied to the data. They allow the extrapolation of experimental data beyond the time available for measurement. The model calculations reveal the presence of sink effects. The role of the chamber walls as sinks can be determined more reliably if constant sources of an organic compound are placed into the chamber and their increase in concentration with time is compared with the theoretical predictions neglecting sink effects.

  18. Design and construction of an interface system for the extrapolation chamber from the beta secondary standard

    International Nuclear Information System (INIS)

    The Interface System for the Extrapolation Chamber (SICE) contains several devices handled by a personal computer (PC), it is able to get the required data to calculate the absorbed dose due to Beta radiation. The main functions of the system are: a) Measures the ionization current or charge stored in the extrapolation chamber. b) Adjusts the distance between the plates of the extrapolation chamber automatically. c) Adjust the bias voltage of the extrapolation chamber automatically. d) Acquires the data of the temperature, atmospheric pressure, relative humidity of the environment and the voltage applied between the plates of the extrapolation chamber. e) Calculates the effective area of the plates of the extrapolation chamber and the real distance between them. f) Stores all the obtained information in hard disk or diskette. A comparison between the desired distance and the distance in the dial of the extrapolation chamber, show us that the resolution of the system is of 20 μm. The voltage can be changed between -399.9 V and +399.9 V with an error of less the 3 % with a resolution of 0.1 V. These uncertainties are between the accepted limits to be used in the determination of the absolute absorbed dose due to beta radiation. (Author)

  19. Medical applications of multi-wire proportional chambers

    International Nuclear Information System (INIS)

    The adaption of Multi-Wire Proportional Chambers (MWPC) for medical applications has necessitated bi-dimensional readout. This is achieved by analysing signals induced onto the cathode planes. At a useful X-ray energy of 40 to 45 keV, just above the K absorption edge in Xenon, the efficiency and resolution are both optimized. Poor resolution events due to K shell fluorescent capture and Auger emission, or L shell photo-electron emission, may be rejected by using energy discrimination - resulting in approximately halving the efficiency to 8% for a 1.6 cm thick atmospheric pressure chamber, but with sub millimeter inherent resolution. This is still far inferior to film resolution, but the MWPC is useful when numbers are required for computation or retrieval. Short descriptions of the MWPC applications to bone density measurements and tomography are given. Its use when pressurized as a gamma camera is discussed, and it is concluded that it may prove useful as a portable special purpose camera, or as one with a very large area thus compensating for low efficiency. Developments with liquid filled chambers are given and also the promising positron imaging hybrid MWPC. (author)

  20. Stability results of a free air ionization chamber in standard mammography beams

    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 Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Free air ionization chambers are absolute dosimeters, because they can measure basic physical quantities directly without the need of their calibration in a standard radiation beam. They are used for measuring exposure and air kerma in X and gamma radiation beams. The Calibration Laboratory (LCI) of IPEN has a free air ionization chamber of the cylindrical type for low energies. The characterization of this ionization chamber was already performed and reported in a previous study. After a modification in the support of the micrometers used for the movement of the internal cylinder devices, the tests were redone. The objective of this work was to present the new alignment protocol of the free air ionization chamber in low energies of X-ray beams of standard mammography qualities, assuring the positioning reproducibility, and new results of stability tests performed with the application of this protocol will be presented. (author)

  1. Ozone measurement techniques: Traditional versus chamber absorption methods with ultraviolet led as

    International Nuclear Information System (INIS)

    This article describes the traditional techniques for measuring ozone in the lower atmosphere, emphasizing the absorption chamber method with UV LEO diode as a light source for high performance; Ends with an analysis of the advantages and disadvantages of each method.

  2. 3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies

    International Nuclear Information System (INIS)

    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.

  3. Improved Spin-Dependent WIMP Limits from a Bubble Chamber

    CERN Document Server

    Behnke, E; Cooper, P S; Crum, K; Crisler, M; Hu, M; Levine, I; Nakazawa, D; Nguyen, H; Odom, B; Ramberg, E; Rasmussen, J; Riley, N; Sonnenschein, A; Szydagis, M; Tschirhart, R

    2008-01-01

    Bubble Chambers provided the dominant particle detection technology in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on the first period of operation of an ultra-clean, room-temperature bubble chamber containing 1.5 kg of superheated CF$_{3}$I, a target maximally sensitive to spin-dependent and -independent Weakly Interacting Massive Particle (WIMP) couplings. An exposure in excess of 250 kg-days is obtained, with a live-time fraction reaching 80\\%. This illustrates the ability to employ bubble chambers in a new realm, the search for dark matter particles. Improved limits on the spin-dependent WIMP-proton scattering cross section are extracted from this first period. An extreme intrinsic insensitivity to the backgrounds commonly limiting these experiments (a rejection factor for photon-induced electrons of $\\sim\\!10^{-10}$) has been measured in operating conditions leading to the detection of low-energy nuclear recoils such as t...

  4. Dosimetry by paired chambers (TEP-TEG and C-CO2 chamber)

    International Nuclear Information System (INIS)

    Paired chambers are defined as the combination of a neutron and γ sensitive detector and a γ sensitive one, such as the combination of a tissue equivalent ionization chamber (TEP-TEG chamber) and a carbon ionization chamber (C-CO2 chamber). The paired chambers have a feature to be capable of measuring the dose in an irradiation field directly by absorbed dose unit. The authors performed dosimetry by using the paired chambers to investigate the possibility of medical and biological researches by means of the fast neutron beam obtained in the reactor ''Yayoi''. First, the specifications for the paired chambers used, and next, the dose evaluation method are described. The result of dose calibration for the paired chambers shows that the carbon chamber has the reproducibility within 3% deviation and the TEP chamber system has that of 2%. As the examples of measurement, the dosimetry for a living body radiation field by fast neutron beam and that for epithermal neutron irradiation system are reported. The comparison of these dosimetrical results with the other paired chambers seems to show that the satisfactory dosimeter has been produced. The parameters employed for dose conversion are considered to be applicable to the measurement of the epithermal neutron irradiation system. (Wakatsuki, Y.)

  5. The Drift Chambers Of The Nomad Experiment

    CERN Document Server

    Anfreville, M G; Authier, M; Baldisseri, Alberto; Banner, M; Besson, N; Bouchez, J; Castera, A; Cloué, O; Dumarchez, J; Dumps, Ludwig; Gangler, E; Gosset, J; Hagner, C; Jollec, C; Lachaud, C; Letessier-Selvon, A A; Lévy, J M; Linssen, Lucie; Meyer, J P; Ouriet, J P; Passerieux, J P; Pédrol, T; Placci, Alfredo; Poinsignon, J; Popov, B; Rathouit, P; Schahmaneche, K; Stolarczyk, T; Urós, V; Vannucci, François; Vo, M K; Zaccone, Henri

    2002-01-01

    We present a detailed description of the drift chambers used as an active target and a tracking device in the NOMAD experiment at CERN. The main characteristics of these chambers are a large area, a self supporting structure made of light composite materials and a low cost. A spatial resolution of 150 microns has been achieved with a single hit efficiency of 97%.

  6. Supersonic Jet Interactions in a Plenum Chamber

    Directory of Open Access Journals (Sweden)

    K. M. Venugopal

    2004-07-01

    Full Text Available Understanding thè supersonic jet interactions in a plenum chamber is essential for thè design of hot launch systems. Static tests were conducted in a small-scale rocket motor ioaded with a typical nitramine propellaiit to produce a nozzle exit Mach number of 3. This supersonic jet is made to interact with plenum chambers having both open and closed sides. The distance between thè nozzle exit and thè back piate of plenum chamber are varied from 2. 5 to 7. 0 times thè nozzle exit diameter. The pressure rise in thè plenum chamber was measured using pressure transducers mounted at different locatìons. The pressure-time data were analysed to obtain an insight into thè flow field in thè plenum chamber. The maximum pressure exerted on thè back piate of plenum chamber is about 25-35 per cent. of thè maximum stagnation pressure developed in thè rocket motor. Ten static tests were carried out to obtain thè effect of axial distance between thè nozzle exit and thè plenum chamber back piate, and stagnation pressure in thè rocket motoron thè flow field in thè open-sided and closed-sided plenum chambers configurations.

  7. Space Power Facility Reverberation Chamber Calibration Report

    Science.gov (United States)

    Lewis, Catherine C.; Dolesh, Robert J.; Garrett, Michael J.

    2014-01-01

    This document describes the process and results of calibrating the Space Environmental Test EMI Test facility at NASA Plum Brook Space Power Facility according to the specifications of IEC61000-4-21 for susceptibility testing from 100 MHz to 40 GHz. The chamber passed the field uniformity test, in both the empty and loaded conditions, making it the world's largest Reverberation Chamber.

  8. Wet drift chambers for precise luminosity

    International Nuclear Information System (INIS)

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

  9. Ionization-chamber smoke detector system

    Science.gov (United States)

    Roe, Robert F.

    1976-10-19

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system is designed to reduce false alarms caused by fluctuations in ambient temperature. Means are provided for periodically firing the gas discharge triode and each time recording the triggering voltage required. A computer compares each triggering voltage with its predecessor. The computer is programmed to energize an alarm if the difference between the two compared voltages is a relatively large value indicative of particulates in the measuring chamber and to disregard smaller differences typically resulting from changes in ambient temperature.

  10. Compact ion chamber based neutron detector

    Science.gov (United States)

    Derzon, Mark S.; Galambos, Paul C.; Renzi, Ronald F.

    2015-10-27

    A directional neutron detector has an ion chamber formed in a dielectric material; a signal electrode and a ground electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; readout circuitry which is electrically coupled to the signal and ground electrodes; and a signal processor electrically coupled to the readout circuitry. The ion chamber has a pair of substantially planar electrode surfaces. The chamber pressure of the neutron absorbing material is selected such that the reaction particle ion trail length for neutrons absorbed by the neutron absorbing material is equal to or less than the distance between the electrode surfaces. The signal processor is adapted to determine a path angle for each absorbed neutron based on the rise time of the corresponding pulse in a time-varying detector signal.

  11. An Atmospheric Cloud Physics Laboratory for the Space Laboratory

    Science.gov (United States)

    Smith, R.; Anderson, J.; Schrick, B.; Ellsworth, C.; Davis, M.

    1976-01-01

    Results of research and engineering analyses to date show that it is feasible to develop and fly on the first Spacelab mission a multipurpose laboratory in which experiments can be performed on the microphysical processes in atmospheric clouds. The paper presents a series of tables on the Atmospheric Cloud Physics Laboratory, with attention given to experiment classes, the preliminary equipment list (particle generators, optical and imaging devices, particle detectors and characterizers, etc.), initial equipment (scientific equipment subsystems and flight support subsystems), and scientific functional requirements (the expansion chamber, the continuous flow diffusion chamber, the static diffusion chamber, the humidifier, and particle generators).

  12. Exoplanet Atmospheres

    CERN Document Server

    Seager, S

    2010-01-01

    At the dawn of the first discovery of exoplanets orbiting sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of a transiting exoplanet atmosphere, many skeptics discounted it as a one-object, one-method success. Nevertheless, the field is now firmly established, with over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type of exoplanet currently most amenable to study. Highlights include: detection of molecular spectral features; observation of day-night temperature gradients; and constraints on vertical atmospheric structure. Atmospheres of giant planets far from their host stars are also being studied with direct imaging. The ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are we alone?" via detection of atmospheric biosignatures. Two exciting prospects are the immediate focus on transiting super Earths orbiting in the habitable zone of M-dwarfs, and u...

  13. Atmospheric Cloud Physics Laboratory thermal control

    Science.gov (United States)

    Moses, J. L.; Fogal, G. L.; Scollon, T. R., Jr.

    1978-01-01

    The paper presents the development background and the present status of the Atmospheric Cloud Physics Laboratory (ACPL) thermal control capability. The ACPL, a Spacelab payload, is currently in the initial flight hardware development phase for a first flight scheduled in June 1981. The ACPL is intended as a facility for conducting a wide variety of cloud microphysics experimentation under zero gravity conditions. The cloud chambers, which are key elements of the ACPL, have stringent thermal requirements. Thus the expansion chamber inner walls must be uniform to within + or - 0.1 C during both steady-state and transient operation over a temperature range of +30 to -25 C. Design progression of the expansion chamber, from early in-house NASA-MSFC concepts (including test results of a prototype chamber) to a thermal control concept currently under development, is discussed.

  14. Simultaneous determination of Rn-220 and Rn-222 concentrations in atmospheres by cellulose nitrate ionographic detectors

    International Nuclear Information System (INIS)

    A method for the indoor determination of airborne radon and radon daughters is described, based in the utilization of cellulose nitrate (CN) ionographic detectors (LR-115-Kodak-Pathe) These track-etching detectors are coupled to an air sample and to a difusion chamber respectively. In the first system ambient air is pulled through a fiber glass filter for collection of airborne radon daughters (Flow: 230 ml/min). In the second system, the cellulose nitrate detectors is coupled/min). In the second system, the cellulose nitrate detectors is coupled to a difusion chamber electrostatic precipitator arrangement. Here the CN detector will register only the alpha particles given off by the decay products of Rn-222 formed within the sensitive volume of electrostatic precipitator. The construction of calibration curves for the two systems using adequate steady-state concentrations of Rn-220 and Rn-222 in an exposure chamber (1 cubic meter), will allow the use of the system for measurement of measurement of averaged integrated radon concentrations. The CN attached to the CN attached to the air sampler is exposed in the reference atmosphere with and without a mylar filter for discrimination of alpha particles with different energies Field sampling indicated however, that efficiency of the two systems are still low for the measurement of environmental levels of Rn-220 and Rn-222 within houses of the AENR, recommendations for efficienty improvement of the system are proposed

  15. Multiwire proportional chamber with a dielectric film. Numerical study

    International Nuclear Information System (INIS)

    Electrostatical properties of multiwire proportional chambers with a dielectric film of low conductivity are considered. Distribution of the electric field in the chamber was obtained using numerical methods. This allowed investigating the influence of various parameters (chamber geometry, voltage at the electrodes) on the chamber working characteristics. Dependence of the chamber amplitude characteristics on the counting rate was also obtained

  16. Monitored Drift Chambers in the ATLAS Detector

    CERN Multimedia

    Herten, G

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

  17. Comparison among different CT ionization chambers

    International Nuclear Information System (INIS)

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

  18. Pluto's atmosphere

    International Nuclear Information System (INIS)

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references

  19. 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

  20. 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.

  1. Making MUSIC: A multiple sampling ionization chamber

    Science.gov (United States)

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

    2007-08-01

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

  2. Liquid-argon cylindrical pulsed ionization chamber

    International Nuclear Information System (INIS)

    A liquid-argon cylindrical ionization chamber with a working volume of 200 cm2 is described. The chamber anode is made of stainless steel in the form of a hollow cylinder 30 mm in diameter and 140 mm in length. A beryllium bronze wire in diameter of 0.1 mm and at a spacing of 1 mm is used for winding the chamber screen grid. The chamber cathode is a brass thin-walled cylinder having an internal diameter of 56 mm and a height of 156 mm. The cathode-grid gap is 10 mm, the cathode-case gap is 2 mm. A 0.5 l cooling bath filled with liquid nitrogen is used to refrigirate the chamber. The chamber is evacuated to about 10-5 mm Hg. The total concentration of electronegative impurities in argon does not exceed 6x10-9. Dependences of the chamber counting and amplitude responses, on the cathode voltage under irradiation with γ-quanta at energies of 0.898 MeV and 1.836 MeV are given. The value of the energy resolution was evaluated by differentiating the high-energy edge of the Compton spectrum. The total width at a peak half-height constitutes 5% for an electron energy of 1.612 MeV. To achieve better resolution of the chamber it is necessary to reduce preamplifier noises by three times, to increase the working gap of the chamber and decrease the grid-anode gap

  3. Making MUSIC: A multiple sampling ionization chamber

    International Nuclear Information System (INIS)

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

  4. 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.

  5. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

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

  6. Growing and Analyzing Biofilms in Flow Chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

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

  7. Development of an α grid ionization chamber

    International Nuclear Information System (INIS)

    The article introduces the parallel grid ionization chamber used to measure the α radioactivity, which has a independent vacuum system. The system is composed of main body of the chamber, gas-filled and electronics system. Energy resolution is 25 keV for 239Pu, background is 4 counts for one hour from 4 MeV to 6 MeV energy range, detect efficiency approach to 50%. The chamber can measure the energy of nuclide, analyze the structure, moreover authenticate both the nuclide and the relative and absolute content. (authors)

  8. APS Storage Ring vacuum chamber fabrication

    International Nuclear Information System (INIS)

    The 1104-m circumference Advanced Photon Source Storage Ring Vacuum System is composed of 240 individual sections, which are fabricated from a combination of aluminum extrusions and machined components. The vacuum chambers will have 3800 weld joints, each subject to strict vacuum requirements, as well as a variety of related design criteria. The vacuum criteria and chamber design are reviewed, including a discussion of the weld joint geometries. The critical fabrication process parameters for meeting the design requirements are discussed. The experiences of the prototype chamber fabrication program are presented. Finally, the required facilities preparation for construction activity is briefly described. 6 refs., 6 figs., 1 tab

  9. LEP vacuum chamber, cross-section

    CERN Multimedia

    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.

  10. 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

  11. A system for measuring fluxes of trace gases to and from soil and vegetation with a chamber technique

    International Nuclear Information System (INIS)

    A mobile system for measurements of gaseous fluxes of SO2 NOx, O3 and water vapour between the atmosphere and the vegetation soil system using a chamber technique is described. Equipment, instruments and instrumental sensitivities are listed. A gas-handling system including calibration procedures and information on the chamber construction is also presented. With this system it is possible to make measurements using a wide range of concentrations including subambient levels. The environment in the chamber can be kept very close to ambient conditions. The mechanisms regulating the flux can be studied. A limitation of this system is the problem of extrapolating the fluxes obtained to larger areas. (author)

  12. One meter holographic bubble chamber for TEVATRON neutrino experiments

    International Nuclear Information System (INIS)

    A one meter holographic bubble chamber was constructed for Fermilab TEVATRON neutrino experiments. Bubble chamber and optics are briefly outlined. Developments in holography for this bubble chamber and two types of reconstruction projectors are reported. (orig.)

  13. 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.

  14. Room temperature liquid ionization chambers using tetramethylsilane

    International Nuclear Information System (INIS)

    Ionization pulse signals due to 207Bi conversion electrons were observed in ionization chambers filled with tetramethylsilane which was purified by a simple method. Pulse height spectra and its variation with the electric field were measured. (orig.)

  15. 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....

  16. 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.

  17. 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...

  18. 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...

  19. Development of a Bioaerosol single particle detector (BIO IN) for the Fast Ice Nucleus CHamber FINCH

    OpenAIRE

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

    2010-01-01

    In this work we present the setup and first tests of our new BIO IN detector. This detector was constructed to classify atmospheric ice nuclei (IN) for their biological content. It is designed to be coupled to the Fast Ice Nucleus CHamber FINCH. If one particle acts as an ice nucleus, it will be at least partly covered with ice at the end of the development section of the FINCH chamber. The device combines an auto-fluorescence detector and a circular depolarization detector ...

  20. Performance of a prototype drift chamber with 100 MHz FADC readout

    International Nuclear Information System (INIS)

    Rectangular drift chamber cells have been constructed and tested using an electron test beam facility at DESY. A systematic study of the time, space, energy and double track resolution with a 100 MHz FADC readout is presented. The spatial resolution is 100 μm to 120 μm and the double track resolution is 2.5 mm with an Ar:C2H6 (50:50) gas mixture at atmospheric pressure. The dE/dx resolution obtained corresponds to 6% resolution for a 72-layer chamber. (author)

  1. Radionuclide dispersion in the atmosphere

    International Nuclear Information System (INIS)

    The instantaneous liberation of radionuclides in the atmosphere is studied in three dimensions, according to the formalism of the diffusion theory. The analytical solution, expose to gravitational and an atmospherical effects, is combined with the discretization of space and time in the calculation of levels of exposure. A typical inventory (for a PWR) was considered in the calculation of immersion doses, and the results permitted a comparative analysis among the different existing models. (Author)

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

    Science.gov (United States)

    Nagare, Baban; Marcolli, Claudia; Welti, André; Stetzer, Olaf; Lohmann, Ulrike

    2016-07-01

    Ice nucleating particles (INPs) in the atmosphere are responsible for glaciating cloud droplets between 237 and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. To date, direct comparisons of contact and immersion freezing with the same INP, for similar residence times and concentrations, are lacking. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data were obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH) using 80 µm diameter droplets, which can interact with INPs for residence times of 2 and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter Arizona Test Dust (ATD) and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm-3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm-3 for AgI. For concentrations refer to a contact nucleation process that is enhanced compared to immersion freezing due to the position of the INP on the droplet, and we discriminate it from collisional contact freezing, which assumes an enhancement due to the collision of the particle with the droplet. For best comparison with contact freezing results, immersion freezing experiments of the same INPs were performed with the continuous flow diffusion chamber Immersion Mode Cooling ch

  3. 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.

  4. 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.

  5. Electrostatic problems in multiwire proportional chambers

    CERN Document Server

    Erskine, George A

    1972-01-01

    Starting from the known complex potential of an infinite grid of thin wires lying between parallel grounded electrodes, the following problems are discussed: 1) the electrostatic coupling between wires, 2) the effect of varying the diameter of a single wire, 3) the effect of displacing a single wire. Figures are given which show the magnitude of these effects for a symmetric chamber of arbitrary dimensions. The computer generation of field plots for proportional chambers is briefly discussed. (5 refs).

  6. The CDF vertex time projection chamber system

    International Nuclear Information System (INIS)

    The vertex time projection chamber (VTPC) system is one of the major components of the charged particle tracking system for the Collider Detector at Fermilab (CDF). The chambers cover about seven units of pseudorapidity (η) and must be capable of handling substantially more than the 30-35 charged particle tracks produced by typical anti pp collisions at center-of-mass energies of 1.8 TeV. The chambers are optimized to provide the good pattern recognition in the r-z view required to locate the event vertex, measure the overall event topology, and to complement the r-φ tracking in the large axial wire drift chamber that surrounds them. The chambers provide r-z information using TDC data from sense wire signals. Information on the φ of tracks is obtained from cathode pad signals on a subset of chambers read out by a FADC system. A similar system measures dE/dx of tracks in the forward cones surrounding the exiting beams. Because of the large number of photons that pass through the detector during each collision, novel techniques are required to reduce the amount of material in the chamber. These techniques include a custom surface mount integrated circuit preamplifier, epoxy-graphite and Kapton covered foam structural members, and miniature coaxial signal cables. The mechanical construction of the chamber, radiation length vs angle, and details of the electronics are described. The event reconstruction, corrections, and preliminary performance results for 1.8 TeV anti pp collisions are also discussed. (orig.)

  7. Impact excited strain gage for multiwire chambers

    International Nuclear Information System (INIS)

    A method for measuring multiwire chamber tension by impact excitation of mechanical oscillations and measuring their periods is described. A flowsheet of an automated electron gaugeis presented; the gauge provides high efficiency and possibility for measurements under conditions of difficult availability of the multiwire chamber system. The range of tension measurements is 0.5-70 g for gilded tugsten wires of 20 μm in diameter and 60 cm length

  8. Virtual Calibration Chamber CPT on Ticino sand

    OpenAIRE

    Butlanska, Joanna; Arroyo Alvarez de Toledo, Marcos; Gens Solé, Antonio

    2010-01-01

    The following paper surnmarizes results of CPT's performed in virtual calibration chamber (VCC) built with a 3D model based on the distinct element method (DEM). A discrete material tailored to mimic Ticino sand is tested at different densities, stress and stress history. The limit cone tip resistance from the numerical experiments shows quantitative agreement with different empirical curves summarizing previous tests on Ticino sand in physical calibration chambers (ENEL and ISMES).

  9. Numerical simulation of magma chamber dynamics.

    Science.gov (United States)

    Longo, Antonella; Papale, Paolo; Montagna, Chiara Paola; Vassalli, Melissa; Giudice, Salvatore; Cassioli, Andrea

    2010-05-01

    Magma chambers are characterized by periodic arrivals of deep magma batches that give origin to complex patterns of magma convection and mixing, and modify the distribution of physical quantities inside the chamber. We simulate the transient, 2D, multi-component homogeneous dynamics in geometrically complex dyke+chamber systems, by means of GALES, a finite element parallel C++ code solving mass, momentum and energy equations for multi-component homogeneous gas-liquid (± crystals) mixtures in compressible-to-incompressible flow conditions. Code validation analysis includes several cases from the classical engineering literature, corresponding to a variety of subsonic to supersonic gas-liquid flow regimes (see http://www.pi.ingv.it/~longo/gales/gales.html). The model allows specification of the composition of the different magmas in the domain, in terms of ten major oxides plus the two volatile species H2O and CO2. Gas-liquid thermodynamics are modeled by using the compositional dependent, non-ideal model in Papale et al. (Chem.. Geol., 2006). Magma properties are defined in terms of local pressure, temperature, and composition including volatiles. Several applications are performed within domains characterized by the presence of one or more magma chambers and one or more dykes, with different geometries and characteristic size from hundreds of m to several km. In most simulations an initial compositional interface is placed at the top of a feeding dyke, or at larger depth, with the deeper magma having a lower density as a consequence of larger volatile content. The numerical results show complex patterns of magma refilling in the chamber, with alternating phases of magma ingression and magma sinking from the chamber into the feeding dyke. Intense mixing takes place in feeding dykes, so that the new magma entering the chamber is always a mixture of the deep and the initially resident magma. Buoyant plume rise occurs through the formation of complex convective

  10. A very large multigap resistive plate chamber

    CERN Document Server

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

    1999-01-01

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

  11. Characteristic parameters of drift chambers calculation

    International Nuclear Information System (INIS)

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

  12. The OPAL jet chamber full scale prototype

    International Nuclear Information System (INIS)

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

  13. State of the art incubator for controlled atmosphere studies

    DEFF Research Database (Denmark)

    Nielsen, Per Væggemose

    1998-01-01

    A state of the art incubator for studies of the biological effect of controlled atmosphere was designed. Working conditions are all combinations of: Temperature (5 to 40°C), Humidity (25 to 98%), oxygen (0.1 to 30%) and nitrogen (0.1 to 50%). Several points were given specific considerations...... without interfering with the atmosphere inside the chamber....

  14. High intensity electromagnetic field gerenation using a transportable reverberation chamber

    OpenAIRE

    Leferink, F.B.J.

    2008-01-01

    A reverberation chamber can create very high field strength with moderate input power. Existing chambers are making use of a paddle wheel to change the resonant modes in the chamber. A transportable reverberation chamber with vibrating walls will be presented. Inside this Vibrating Intrinsic Reverberation Chamber (VIRC) a diffuse, statistically uniform electromagnetic field is created, without the use of a mechanical, rotating, mode stirrer. This chamber results in a better homogeneity and in...

  15. Close cathode chamber: Low material budget MWPC

    International Nuclear Information System (INIS)

    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. -- Highlights: ► Asymmetric multi-wire proportional chamber, called the Close Cathode Chamber, is studied. ► Large size construction feasibility up to 1 m wire length is demonstrated in test beam and cosmic rays. ► Reduction of dependence of gas gain on chamber internal pressure is directly demonstrated. ► Position resolution and signal formation is shown to be compatible with classical MWPC.

  16. The GODDESS ionization chamber: developing robust windows

    Science.gov (United States)

    Blanchard, Rose; Baugher, Travis; Cizewski, Jolie; Pain, Steven; Ratkiewicz, Andrew; Goddess Collaboration

    2015-10-01

    Reaction studies of nuclei far from stability require high-efficiency arrays of detectors and the ability to identify beam-like particles, especially when the beam is a cocktail beam. The Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies (GODDESS) is made up of the Oak Ridge-Rutgers University Barrel Array (ORRUBA) of silicon detectors for charged particles inside of the gamma-ray detector array Gammasphere. A high-rate ionization chamber is being developed to identify beam-like particles. Consisting of twenty-one alternating anode and cathode grids, the ionization chamber sits downstream of the target chamber and is used to measure the energy loss of recoiling ions. A critical component of the system is a thin and robust mylar window which serves to separate the gas-filled ionization chamber from the vacuum of the target chamber with minimal energy loss. After construction, windows were tested to assure that they would not break below the required pressure, causing harm to the wire grids. This presentation will summarize the status of the ionization chamber and the results of the first tests with beams. This work is supported in part by the U.S. Department of Energy and National Science Foundation.

  17. Quality control of ATLAS muon chambers

    CERN Document Server

    Fabich, Adrian

    ATLAS is a general-purpose experiment for the future Large Hadron Collider (LHC) at CERN. Its Muon Spectrometer will require ∼ 5500m2 of precision tracking chambers to measure the muon tracks along a spectrometer arm of 5m to 15m length, embedded in a magnetic field of ∼ 0.5T. The precision tracking devices in the Muon System will be high pressure drift tubes (MDTs). Approximately 370,000 MDTs will be assembled into ∼ 1200 drift chambers. The performance of the MDT chambers is very much dependent on the mechanical quality of the chambers. The uniformity and stability of the performance can only be assured providing very high quality control during production. Gas tightness, high-voltage behaviour and dark currents are global parameters which are common to gas detectors. For all chambers, they will be tested immediately after the chamber assembly at every production site. Functional tests, for example radioactive source scans and cosmic-ray runs, will be performed in order to establish detailed performan...

  18. A large scale knife-edge chamber

    International Nuclear Information System (INIS)

    To date, three different tracking detectors, Straw Tube Chamber, Silicon Strip Detector and Scintillation Fiber Detector, as well as their combinations, have been proposed for the SSC experiments. However all of them have their own problems as tracking detectors for use in very high luminosity experiment at the SSC. Scintillation fiber detector is excellent in its speed, spatial resolution and low occupancy. However the fatal problem is the readout devices. Questions on its radiation hardness have not yet been totally solved. As a solution to this challenge, a knife-edge chamber was proposed. The knife-edge chamber is essentially a multi-wire proportional chamber. This chamber has, however, a drawback which is shared with the silicon strip detector, i.e., the size of a single chamber is limited by that of the silicon wafer. Recently at KEK, a program has been started to overcome this problem. The KEK method is to make v-shape grooves on a metal plate, such as a nickel-plated steel, and to use the metal plate as a negative to make sharp-edged electrodes. After this process, there are two possibilities, which are under consideration at the moment. The first possibility is to use the electroforming technique. The second possibility is to use the plastic molding technique by using the machined metal plate as a negative. The KEK machine shop has recently built a high precision shaper machine to produce gratings for synchrotron radiation research. (N.K.)

  19. Chamber for Growing and Observing Fungi

    Science.gov (United States)

    Pierson, Duane L.; Molina, Thomas C.

    2005-01-01

    A chamber has been designed to enable growth and observation of microcolonies of fungi in isolation from the external environment. Unlike prior fungus-growing apparatuses, this chamber makes it possible to examine a fungus culture without disrupting it. Partly resembling a small picture frame, the chamber includes a metal plate having a rectangular through-thethickness opening with recesses for a top and a bottom cover glass, an inlet for air, and an inlet for water. The bottom cover glass is put in place and held there by clips, then a block of nutrient medium and a moisture pad are placed in the opening. The block is inoculated, then the top cover glass is put in place and held there by clips. Once growth is evident, the chamber can be sealed with tape. Little (if any) water evaporates past the edges of the cover glasses, and, hence there is little (if any) need to add water. A microscope can be used to observe the culture through either cover glass. Because the culture is sealed in the chamber, it is safe to examine the culture without risking contamination. The chamber can be sterilized and reused.

  20. Trace Contaminant Testing with the Orion Atmosphere Revitalization Technology

    Science.gov (United States)

    Button, Amy B.; Sweterlitsch, Jeffrey J.; Broerman, Craig D.; Campbell, Melissa L.

    2010-01-01

    Every spacecraft atmosphere contains trace contaminants resulting from offgassing by cabin materials and human passengers. An amine-based carbon dioxide (CO2) and water vapor sorbent in pressure-swing regenerable beds has been developed by Hamilton Sundstrand and baselined for the Orion Atmosphere Revitalization System (ARS). Part of the risk mitigation effort for this new technology is the study of how atmospheric trace contaminants will affect and be affected by the technology. One particular area of concern is ammonia, which, in addition to the normal spacecraft sources, can also be offgassed by the amine-based sorbent. In the spring of 2009, tests were performed at Johnson Space Center (JSC) with typical cabin atmosphere levels of five of the most common trace gases, most of which had not yet been tested with this technology. A subscale sample of the sorbent was exposed to each of the chemicals mixed into a stream of moist, CO2-laden air, and the CO2 adsorption capacity of the sorbent was compared before and after the exposure. After these typical-concentration chemicals were proven to have negligible effect on the subscale sample, tests proceeded on a full-scale test article in a sealed chamber with a suite of eleven contaminants. To isolate the effects of various test rig components, several extended-duration tests were run: without injection or scrubbing, with injection and without scrubbing, with injection of both contaminants and metabolic CO2 and water vapor loads and scrubbing by both the test article and dedicated trace contaminant filters, and with the same injections and scrubbing by only the test article. The high-level results of both the subscale and full-scale tests are examined in this paper.

  1. Bulkhead chamber ignition for internal combustion engines. Schottkammerzuendung fuer Verbrennungsmotore

    Energy Technology Data Exchange (ETDEWEB)

    Fox, G.

    1990-12-06

    Bulkhead chamber ignition makes for reliable ignition of different fuels (e.g. petrol or diesel) in internal combustion engines (multifuel engine) that can be operated with an extremely lean fuel-air mixture. This is realized by an open chamber (referred to as bulkhead chamber in the following) inside the combustion chamber which diverts a fraction of the compressed fuel-air mixture from the combustion chamber. After this the pressure in the bulkhead chamber is increased until the mixture ignites spontaneously. The combustion pressure drives back the piston and opens the bulkhead chamber. Then the compressed fuel-air mixture in the combustion chamber is ignited by the released combustion gas.

  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. 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

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

    Directory of Open Access Journals (Sweden)

    C. Wittbom

    2014-04-01

    Full Text Available 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 black carbon 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 volatile organic compounds (IVOC 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 (POA or SOA, (III particle size, and (IV particle morphology. Applying κ-Köhler theory, using a κSOA value of 0.13 (derived from independent input parameters

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

    OpenAIRE

    Peter Križan; Miloš Matúš; Jaan Kers; Djordje Vukelić

    2012-01-01

    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 pressi...

  6. 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.

  7. Characterization and testing of a new environmental chamber designed for emission aging studies

    Science.gov (United States)

    Leskinen, A.; Yli-Pirilä, P.; Kuuspalo, K.; Sippula, O.; Jalava, P.; Hirvonen, M.-R.; Jokiniemi, J.; Virtanen, A.; Komppula, M.; Lehtinen, K. E. J.

    2014-06-01

    A 29 m3 Teflon chamber, designed for aging studies of combustion aerosols, at the University of Eastern Finland is described and characterized. The chamber belongs to a research facility, called Ilmari, where small-scale combustion devices, a dynamometer for vehicle exhaust studies, dilution systems, the chamber, as well as cell and animal exposure devices are side by side under the same roof. The small surface-to-volume ratio of the chamber enables reasonably long experiment times, with particle wall loss rate constants of 0.088, 0.080, 0.045, and 0.040 h-1 for polydisperse, 50, 100, and 200 nm monodisperse aerosols, respectively. The NO2 photolysis rate can be adjusted from zero to 0.62 min-1. The irradiance spectrum is centered at 365 nm and the maximum irradiance, produced by 160 blacklight lamps, is 29.7 W m-2, which corresponds to the UV irradiance in Central Finland at noon on a sunny day in the midsummer. The temperature inside the chamber is uniform and can be kept at 25 ± 1 °C when half of the blacklights are on. The chamber is kept in an overpressure with a moving top frame, which prevents sample dilution and contamination from entering the chamber during an experiment. The functionality of the chamber was tested with oxidation experiments of toluene, resulting in secondary organic aerosol (SOA) yields of 33-44%, depending on the initial conditions, such as the NOx concentration. The highest gaseous oxidation product yields of 14.4-19.5% were detected with ions corresponding to 2-butenedial (m/z 73.029) and 4-oxo-2-pentenal (m/z 99.044). Overall, reasonable yields of SOA and gaseous reaction products, comparable to those obtained in other laboratories, were obtained.

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

    Directory of Open Access Journals (Sweden)

    R. J. Cotton

    2007-01-01

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

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

    Science.gov (United States)

    1976-01-01

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

  10. 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...... 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......” 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....

  11. Exoplanetary Atmospheres

    CERN Document Server

    Madhusudhan, Nikku; Fortney, Jonathan; Barman, Travis

    2014-01-01

    The study of exoplanetary atmospheres is one of the most exciting and dynamic frontiers in astronomy. Over the past two decades ongoing surveys have revealed an astonishing diversity in the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formation histories, just as have been pursued for solar system planets over the past century. Exoplanetary atmospheres provide a direct means to address these questions via their observable spectral signatures. In the last decade, and particularly in the last five years, tremendous progress has been made in detecting atmospheric signatures of exoplanets through photometric and spectroscopic methods using a variety of space-borne and/or ground-based observational facilities. These observations are beginning to provide important constraints...

  12. Staging atmospheres

    DEFF Research Database (Denmark)

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

    2015-01-01

    . Nevertheless, people’s experience of the environment is sought manipulated in a variety of contexts, often without offering a less ‘true’ experience of a situation than if it had not been manipulated by people. In fact, orchestrations of space are often central to sociality, politics and aesthetics. This...... introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  13. 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.

  14. Postdischarge deionization in small-gap spark chambers

    International Nuclear Information System (INIS)

    The recovery of the pulse electrical strength of spark chambers with electrodes out of aluminium foil for two values of the interelectrode gap (1.0 and 0.6) has been investigated experimentally in relation to the electric conditions and composition of the gas mixture. The spark chambers have been filled with Ne + He, Ne, and He at atmospheric pressure with the addition of a few percent ethanol vapor, isopropanol vapour, and 0.01% freon-12. The curves of the electrical strength recovery time as a function of the clearing field potential are shown, as well as the extrapolated values of the reduction time versus the clearing field potential. The obtained numerical results are tabulated. The recovery time is shown to be determined to a considerable degree by the drift time of the ion column and the concominant secondary processes, i.e. secondary electron emission from the collisions of the noble gas ions with the electrodes, the charge-exchange between the Ne+ (or He+) ions and spirit molecules

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

    CERN Multimedia

    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.

  16. Observation of heavy cosmic-ray primaries by means of light-weight-type emulsion chamber

    International Nuclear Information System (INIS)

    We have exposed an emulsion chamber with full use of screen-type X-ray film at a level of 11.7 g/cm2 for ∼20 h. Our chamber consists of a sandwich of stainless target (500 μm thickness each) and sensitive materials such as Fuji No.200-type X-ray film (non screen type), nuclear emulsion plate and screen-type X-ray film (Fuji Grenex HR8 + Fuji RXOH film). Since electromagnetic calorimeter layer is removed, it makes possible to construct large size emulsion chamber with light weight. We discuss the possibility of a screen-type X-ray film for the observation of heavy cosmic ray primaries, and report preliminary results obtained by this observation, particularly on an interesting event showing an extremely penetrative nature in the atmosphere with high effective charge , Z = 36∼40. (author)

  17. 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.

  18. Innovations in gas filled ionisation chambers

    International Nuclear Information System (INIS)

    The gas filled parallel plate ion chamber and coaxial cylindrical ion chambers are widely used for detection of nuclear radiations for more than hundred years. Thin Metal electrodes or metal coated planes are used as cathode and anodes in both parallel plate and cylindrical ionization chambers since its invention. For neutral particle detection, either the ionising medium or a coated electrode surface is used as a converter material for producing secondary charged particles which are detected in these ionisation chambers. Boron, and 235U are coated as thin layer on the cathode surface with optimum thickness to give maximum neutron detection sensitivity. The neutron sensitivity mostly depends upon the coated surface area and to enhance the neutron sensitivity diameter and the length/ diameter of the coated electrodes have to be increased which also results in an increase in the volume of the counter. For many applications, it is necessary to reduce the size of the counter by a factor of 2 to 5 but having the same efficiency. Recently this has been achieved by designing a non planar electrode surface/ s which has surface area larger by a factor or up to five keeping the external dimensions the same. By using this new technique, it is possible to increase the coated area up to 5 times, without changing the overall dimensions of the counter both for proportional counters and ion chambers. The three methods have been developed to enhance the neutron sensitivity the use of: additional coated wires, coated baffles, coated fins: in sensitive volume of gas detectors. The introduction of these three-dimensional boron coated structures into the sensitive volume without enlarging the outer detector dimensions increases the Boron/Uranium content in the sensitive region without any significant change in the nature of the pulses from these counters. In the newly developed Wire Plane Chambers both in the DC mode and pulse mode, wire planes have been used as anode and cathodes with

  19. D. phi. vertex drift chamber construction and test results

    Energy Technology Data Exchange (ETDEWEB)

    Clark, A.R.; Goozen, F.; Grudberg, P.; Klopfenstein, C.; Kerth, L.T.; Loken, S.C.; Oltman, E.; Strovink, M.; Trippe, T.G.

    1991-05-01

    A jet-cell based vertex chamber has been built for the D{O} experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO{sub 2}(95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with (9.74+8.68( E -1.25)) {mu}m/nsec where E is the electric field strength in (kV/cm < E z 1.6 kV/cm.) An intrinsic spatial resolution of 60 {mu}m or better for drift distances greater than 2 mm is measured. The track pair efficiency is estimated to be better than 90% for separations greater than 630 {mu}m. 8 refs., 6 figs., 1 tab.

  20. Thermoelastic analysis of solar window of a vacuum chamber

    Science.gov (United States)

    Amba-Rao, C. L.; Soni, S. R.

    1975-01-01

    It has been noted during space simulation test programs that the chamber penetration window becomes the limiting factor as the solar intensity increases. The temperature at the center of the window normally attains a level of 550 C, while the edge temperature remains at about 35 C. The stresses produced by this thermal gradient combined with the atmospheric pressure are studied within the framework of classical theory of elasticity. The solution for the problem is obtained by solving the static uncoupled thermoelastic equations for a circular blank, subjected to nonuniform heat on one face, by introduction of two auxiliary variables. The displacements are expressed in terms of Bessel functions and parameters of interest are computed at various mesh points of the window. The maximum principal stresses thus obtained show that even with steep temperature gradient, the safety factor is acceptable.

  1. Organization of inspection of bubble chamber photographs

    International Nuclear Information System (INIS)

    A program for inspection of bubble chamber photographs is described. The program was developed for a DEC-10 computer and is designed for PUOS-2M and PUOS-4 semiautomatic inspection and measuring projectors. Formalization of the inspection procedure allows it to be used for various physics experiments. As an example the authors consider the problem of the physical inspection in an experiment on scattering of kaons plus with momenta of 70 GeV/c by protons performed in a BEBC chamber. Primary vertices were analyzed in the following cases: low quality of reconstruction of parameters in the geometric program; lack of agreement of the number of reconstructed tracks with that indicated by inspection; and unmeasured events and events with candidate tracks for identification of proton tracks by degree of ionization. The performance of the program in these cases is evaluated. The program has been used to process 50,000 events recorded with a BEBC chamber as well as experiments recorded with the SCAT chamber and the European Hybrid Spectrometer using the RCBC, LEBC and HOLEBC chambers

  2. Investigation of Swirling Flows in Mixing Chambers

    Directory of Open Access Journals (Sweden)

    Jyh Jian Chen

    2011-01-01

    Full Text Available This investigation analyzed the three-dimensional momentum and mass transfer characteristics arising from multiple inlets and a single outlet in micromixing chamber. The chamber consists of a right square prism, an octagonal prism, or a cylinder. Numerical results which were presented in terms of velocity vector plots and concentration distributions indicated that the swirling flows inside the chamber dominate the mixing index. Particle trajectories were utilized to demonstrate the rotational and extensional local flows which produce steady stirring, and the configuration of colored particles at the outlet section expressed at different Re represented the mixing performance qualitatively. The combination of the Taylor dispersion and the vorticity was first introduced and made the mixing successful. The effects of various geometric parameters and Reynolds numbers on the mixing characteristics were investigated. An optimal design of the cylindrical chamber with 4 inlets can be found. At larger Reynolds number, Re>15, more inertia caused the powerful swirling flows in the chamber, and more damping effect on diffusion was diminished, which then increased the mixing performance.

  3. Proportional chambers for the Σ installation

    International Nuclear Information System (INIS)

    Two types of proportional chambers used in experiments with SIGMA set are considered. The main parameters of detecting electronics, high-voltage, low-voltage and gas supplies are presented. The first type chambers consist of the round or square frames of sheet foiled glass-cloth-base laminate, on which surface electrode lands and joints between them are applied by photographic printing. The second type chamber electrodes are also made of the sheet foiled glass-cloth-base laminate as strips arranged at the ends of two rectangular metallic profiles. The chamber sensitive regions vary from 64x64 mm to 768x2500 mm. The chambers are used for more than 15 years in different experiments, such as determination of elastic scattering, study of J/ψ and ψ' particle production, search for charm particles in hadron interactions, measuring the change of π--meson polarizability, study of μ+μ-π- system production. The experience of past years manifested their high efficiency and reliability

  4. Chamber, Target and Final Focus Integrated Design

    International Nuclear Information System (INIS)

    Liquid wall protection, which challenges chamber clearing, has such advantages it's Heavy Ion Fusion's (HIF) main line chamber design. Thin liquid protection from x rays is necessary to avoid erosion of structural surfaces and thick liquid makes structures behind 0.5 m of Flibe (7 mean free paths for 14 MeV neutrons), last the life of the plant. Liquid wall protection holds the promise of greatly increased economic competitiveness. Driver designers require ∼200 beams to illuminate recent target designs from two sides. The illumination must be compatible with liquid wall protection. The ''best'' values for driver energy, gain, yield and pulse rate comes out of well-known trade-off studies. The chamber design is based on several key assumptions, which are to be proven before HIF can be shown to be feasible. The chamber R and D needed to reduce the unknowns and risks depend on resolving a few technical issues such as jet surface smoothness and rapid chamber clearing

  5. Chamber, Target and Final Focus Integrated Design

    International Nuclear Information System (INIS)

    Liquid wall protection, which challenges chamber clearing, has such advantages it's Heavy Ion Fusion's (HIF) main line chamber design. Thin liquid protection from x rays is necessary to avoid erosion of structural surfaces and thick liquid makes structures behind 0.5 m of Flibe (7 mean free paths for 14 MeV neutrons), last the life of the plant. Liquid wall protection holds the promise of greatly increased economic competitiveness. Driver designers require ∼200 beams to illuminate recent target designs from two sides. The illumination must be compatible with liquid wall protection. The ''best'' values for driver energy, gain, yield and pulse rate comes out of well-known trade-off studies. An integrated chamber design, yet to be made, depends on several key assumptions, which are to be proven before HIF can be shown to be feasible. The chamber R and D needed to reduce the unknowns and risks depend on resolving a few technical issues such as jet surface smoothness and rapid chamber clearing

  6. Study and analysis of drift chamber parameters

    International Nuclear Information System (INIS)

    The present work deals mainly with drift chambers. In the first chapter a summary of drift chamber properties is presented. The information has been collected from the extensive bibliography available in this field. A very simple calculation procedure of drift chamber parameters has been developed and is presented in detail in the second chapter. Some prototypes have been made following two geometries (multidrift chamber and Z-chambers). Several installations have been used for test and calibration of these prototypes. A complete description of these installations is given in the third chapter. Cosmic rays, beta particles from a Ru106 radiactive source and a test beam in the WA (West Area) of SPS at CERN have been used for experimental purposes. The analysis and the results are described for the different setups. The experimental measurements have been used to produce a complete cell parametrization (position as function of drift time) and to obtain spatial resolution values (in the range of 200-250 um). Experimental results are in good agreement with numerical calculations. (Author)

  7. Bulky PAH-DNA induced by exposure of a co-culture model of human alveolar macrophages and embryonic epithelial cells to atmospheric particulate pollution; Adduits encombrants a l'ADN dans des cocultures de cellules pulmonaires humaines exposees a une pollution atmospherique particulaire

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Imane; Garcon, Guillaume; Billet, Sylvain; Shirali, Pirouz [Universite Lille Nord de France - Lille (France); Unite de Chimie Environnementale et Interactions sur le Vivant, MREI, Universite du Littoral Cote d' Opale, Dunkerque (France); Andre, Veronique; Le Goff, Jeremie; Sichel, Francois [GRECAN, Universite de Caen Basse-Normandie et centre Francois Baclesse, Caen (France); Roy Saint-Georges, Francoise; Mulliez, Philippe [Service de Pneumologie, Hopital Saint-Philibert, GHICL, Lille (France)

    2012-01-15

    Because of their deep penetration in human lungs, fine airborne particulate matter were described as mainly responsible for the deleterious effects of exposure to air pollution on health. Organic constituents are adsorbed on particles surface and, after inhalation, some (polycyclic aromatic hydrocarbons, PAHs) can be activated into reactive metabolites and can bind to DNA. The formation of bulky DNA adducts has been researched after exposure of mono-and co-cultures of alveolar macrophages (AM) and human embryonic human lung epithelial (L132), to fine air pollution particulate matter Air samples have been collected with cascade impactor and characterized: size distribution (92.15% < 2.5{mu}.m), specific surface area (1 m{sup 2}/g), inorganic (Fe, AI, Ca, Na, K, Mg, Pb, etc.) and organic compounds (PAHs, etc.). {sup 32}P post-labeling method was applied to detect bulky DNA adducts in AM and L132, in mono-and co-cultures, 72 h after their exposure to atmospheric particles at their Lethals and Effects concentrations or (LC or CE) to 50% (i.e. MA: EC{sub 50} = 74.63 {mu}g/mL and L132: LC-5-0 = 75.36 {mu}g/mL). Exposure to desorbed particles (MA: C1= 61.11 {mu}g/mL and L132 : C2 = 61.71 {mu}g/mL) and B[a]P (1 {mu}M) were included. Bulky PAH-DNA adducts were detected in AM in mono-culture after exposure to total particles (Pt), to B[a]P and desorbed particles (Pd). Whatever the exposure, no DNA adduct was detected in L132 in mono-culture. These results are coherent with the enzymatic activities of cytochrome P450 l Al in AM and L132. Exposure of co-culture to Pt, or Pd induced bulky adducts to DNA in AM but not in L132. Exposure to B[a]P alone has altered the DNA of AM and L132, in co-culture. Exposure to Pt is closer to the environmental conditions, but conferred an exposure to amounts of genotoxic agents compared to studies using organic extracts. The formation of bulky DNA adducts was nevertheless observed in AM exposed to Pt, in mono- or co-culture, indicating that

  8. Photographic emulsion versus bubble chambers in charm and beauty searches

    International Nuclear Information System (INIS)

    This chapter discusses the use of visual detectors in the search for charm and other flavors. The photographic emulsion and the bubble chamber techniques are compared. The main difficulties encounted in searching for charmed and beautiful hadrons are related to the short lifetimes of these particles and to their small production cross-sections, even at SPS energies. Resolution, visibility, the data analysis rate, and exposure time are considered. Most of the charmed hadrons present a large variety of decay modes of which only a fraction has been identified to date. First results from CESR indicate that the average charged particle multiplicity in the hadronic decay of beautiful hadrons is as high as 6.31 + or - 0.35; no B meson decay has yet been kinematically reconstructed. The case of hadronic charmed particle production at SPS energies is examined. The data show that 1) the bubble chamber technique (high resolution or holographic optics) is well suited to the study of charmed hadrons with lifetimes in the range 10-13 to 10-12 s; 2) searches for beautiful hadrons remain presently a domain for triggered emulsion experiments due to the smallness of the production cross-sections (provided the lifetime is not much shorter than 10-14 s); and 3) for particles of lifetimes shorter than a few times 10-14 s the emulsion technique is still without competitor

  9. Attempt to visualize cavitation in nozzle chamber of diesel engine by neutron radiography

    International Nuclear Information System (INIS)

    Preliminary experiment using neutron radiography was attempted on visualization of cavitation (= cold boiling) of fuel flow inside the metallic nozzle chamber of diesel engine. Fuel ejection from a diesel-engine nozzle is dependent on the cavitation conditions in fuel flow, subjective to pressure change, were studied using a cooled CCD camera with electric shutter open and with the help of a synchronous chopper for neutron beams which enables to observe visualized flow at 0.5 mm width nozzle chamber, 1 mm diameter sac chamber, and 0.2 mm diameter nozzle hole in a diesel engine. Each images could be obtained with short exposure time from 100 μs to 1 mx. (S. Ohno)

  10. Developing a fast ionization chamber for transfer reaction studies

    Science.gov (United States)

    Chae, K. Y.; Bardayan, D. W.; Smith, M. S.; Schmitt, K. T.; Ahn, S. H.; Peters, W. A.; Strauss, S.

    2011-10-01

    Detection of beam and beam like recoils at far forward angles is often critical for radioactive beam measurements in inverse kinematics. Gas-filled ionization chambers are well suited for these applications, since they have moderately good energy resolution and can take prolonged exposure to beam compared to fragile semiconductor detectors. Conventional ion counters using a Frisch grid, however, have slow response times because the ionized electrons must travel long distances to the anodes. To reduce response times, a fast ion counter using a tilted window and tilted electrodes was developed and tested at ORNL's Holifield Radioactive Ion Beam Facility, modified from an original design by Kimura et al.. The maximum counting rate and energy resolution, along with future plans for using the new ion counter, will be presented. This work was sponsored by the Office of Nuclear Physics, U.S. Department of Energy.

  11. 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.

  12. Toxicologic methods: controlled human exposures.

    OpenAIRE

    Utell, M J; Frampton, M W

    2000-01-01

    The assessment of risk from exposure to environmental air pollutants is complex, and involves the disciplines of epidemiology, animal toxicology, and human inhalation studies. Controlled, quantitative studies of exposed humans help determine health-related effects that result from breathing the atmosphere. The major unique feature of the clinical study is the ability to select, control, and quantify pollutant exposures of subjects of known clinical status, and determine their effects under id...

  13. 21 CFR 884.5225 - Abdominal decompression chamber.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Abdominal decompression chamber. 884.5225 Section... Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber... decompression chamber that was in commercial distribution before May 28, 1976, or that has, on or...

  14. 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.

  15. Design of the CLIC Quadrupole Vacuum Chambers

    CERN Document Server

    Garion, C

    2010-01-01

    The Compact Linear Collider, under study, requires vacuum chambers with a very small aperture, of the order of 8 mm in diameter, and with a length up to around 2 m for the main beam quadrupoles. To keep the very tight geometrical tolerances on the quadrupoles, no bake out is allowed. The main issue is to reach UHV conditions (typically 10-9 mbar static pressure) in a system where the vacuum performance is driven by water outgassing. For this application, a thinwalled stainless steel vacuum chamber with two ante chambers equipped with NEG strips, is proposed. The mechanical design, especially the stability analysis, is shown. The key technologies of the prototype fabrication are given. Vacuum tests are carried out on the prototypes. The test set-up as well as the pumping system conditions are presented.

  16. ON THE ANALYSIS OF BUBBLE CHAMBER TRACKS

    International Nuclear Information System (INIS)

    Since its invention by Glaser in 1953, the bubble chamber has become a most valuable tool in high-energy physics. It combines a number of advantages of various older methods of particle detection: it offers high spatial resolution, rapid accumulation of data, some time resolution, and some choice of the nucleus whose interaction one wants to study (bubble chambers have been made to operate with a large number of different liquids, including H2, D2, He, Xe, and several hydrocarbons). In order to exploit the advantages of spatial resolution and rapid data accumulation, high-speed high-precision analysis procedures must be developed. In this article they discuss some of the problems posed by such analysis. The discussion is based largely on experience gained in performing hydrogen bubble chamber experiments with the University of California's Bevatron (6-Bev proton synchrotron)

  17. Rapid-Cycling Bubble-Chamber, details

    CERN Multimedia

    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.

  18. Drift chamber tracking with neural networks

    International Nuclear Information System (INIS)

    With the very high event rates projected for experiments at the SSC and LHC, it is important to investigate new approaches to on line pattern recognition. The use of neural networks for pattern recognition. The use of neural networks for pattern recognition in high energy physics detectors has been an area of very active research. The authors discuss drift chamber tracking with a commercial analog 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

  19. Posing the first LEAR vacuum chamber

    CERN Multimedia

    1982-01-01

    The photo shows one of the four bending magnets of LEAR. They were of C-type with the opening ('mouth') to the outside of the ring (yoke to the inside). Last preparations are made before the vacuum chamber is slid through the mouth into the magnet. Stochastic cooling pickups/kickers were installed inside the chamber. One can distinguish a large number of feed-throughs on the chamber (leading to the pickup/kicker gaps). The free space in the middle of the block was left to offer room for an internal target in the magnet. This possibility was never exploited. Instead it is used here, to accommodate a pumping port for the high vacuum system. Michel Chanel (left) and Pierre Lefevre admire the mechanics at work.

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

    Science.gov (United States)

    Tuma, J.; Kubata, J.; Betak, V.; Hybl, R.

    2013-04-01

    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. 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.

  2. 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.

  3. Oil shale generators with circular retorting chamber

    International Nuclear Information System (INIS)

    The method of semi-coking oil shale in the circular retorting chamber makes it possible to ensure a more uniform distribution of the heat carriers gas across the shale bed, than in the vertically placed retorting chambers with cross-current heat carrier flow, and in the generators using the counter-current method of heat exchange. This also ensures the most favourable conditions for effective heat transfer in the retorting chamber from the gas flow to the shale bed due to the following factors: absence of the lateral outer walls in the retorting chamber; the concentrical arrangement of the retorting chamber and the passage of the gaseous heat carrier through the shale bed from the periphery of the retort to its center; the bulk of the oil shale charged passes through the hot part of the retorting chamber (i.e. on the side of inlet of the gaseous heat carrier into the shale bed). As a result, processing the oil shale in the generators with circular retorting chambers leads to a decrease in the temperature of oil vapours at the gas outlet on an average from 220 to 150o C and the reduction of the specific air consumption for the process - from 360 to 250 m3/t. According to the calculated data, it ensures an increase in oil yield from 78 to 84% of the Fischer assay oil. The application of the circular retorting chamber in the generators, creates conditions for increased unit throughput rates of the retorts 1.5-2.0 times with a simultaneous increase in the oil yield. For processing oil shales rich in organic material, which readily bitumenize, retorts for a throughput of 1500 tonnes per day have been developed and are already under construction at the P O 'Slantsekhim'. Project designs for the leaner shales can be developed for throughput rates in excess of 5000-6000 tonnes per day. The retorts will have a comparatively small diameter and a simpler design than the 1000 t/day generators being now in operation. (author). 14 refs., 2 tabs., fig

  4. 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

  5. Quasi-Porous Plug With Vortex Chamber

    Science.gov (United States)

    Walsh, J. V.

    1985-01-01

    Pressure-letdown valve combines quasi-porous-plug and vortex-chamber in one controllable unit. Valve useful in fossil-energy plants for reducing pressures in such erosive two-phase process streams as steam/water, coal slurries, or combustion gases with entrained particles. Quasi-Porous Plug consists of plenums separated by perforated plates. Number or size of perforations increases with each succeeding stage to compensate for expansion. In Vortex Chamber, control flow varies to control swirl and therefore difference between inlet and outlet pressures.

  6. Does Pluto have a substantial atmosphere

    International Nuclear Information System (INIS)

    The presence of CH4 ice on Pluto implies that Pluto may have a substantial atmosphere consisting of heavy gases. Without such an atmosphere, sublimation of the CH4 ice would be so rapid on a cosmogonic time scale that either such an atmosphere would soon develop through the exposure of gases trapped in the CH4 ice or else the surface CH4 ice would soon be all sublimated away as other, more stable, ices became exposed. If such stable ices were present from the beginning, the existence of CH4 frosts would also imply that Pluto's present atmosphere contains a remnant of its primordial atmosphere

  7. Desktop exposure system and dosimetry for small scale in vivo radiofrequency exposure experiments

    OpenAIRE

    Gong, Y.J.; Capstick, M.; Tillmann, T; Dasenbrock, C.; Samaras, T; Kuster, N.

    2016-01-01

    This paper describes a new approach to the risk assessment of exposure from wireless network devices, including an exposure setup and dosimetric assessment for in vivo studies. A novel desktop reverberation chamber has been developed for well-controlled exposure of mice for up to 24h per day to address the biological impact of human exposure scenarios by wireless networks. The carrier frequency of 2.45GHz corresponds to one of the major bands used in data communication networks and is modulat...

  8. 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...

  9. Ammonia concentration in an animal radon exposure facility

    International Nuclear Information System (INIS)

    An experimental and dosimetric study on lung tumour induction by inhalation of radon daughters under indoor conditions has been started with the aim of analysing the various factors which determine the risk due to this inhalation. In the experimental part of the study, WAG/Rij rats will be exposed daily for a period of about 18 months in an exposure chamber to a relatively low concentration of radon daughter products. In chronic exposure chambers, ammonia is produced by the action of urease-positive bacteria in urine and faeces. There are reports showing that, in such exposure chambers, the ammonia concentrations will rise beyond acceptable levels. The ammonia concentration as a function of time has therefore been studied, as has means of reducing this concentration. The results demonstrate that, with the addition of Aqualloy granules the ammonia concentration can be reduced over a long period of time to a level for which no cooperative action with the radon exposure is expected. (Auth.)

  10. Brookhaven National Laboratory's multiparticle spectrometer drift chamber system

    International Nuclear Information System (INIS)

    A system of drift chambers is being built to replace the present spark chambers in the Brookhaven National Laboratory's Multiparticle Spectrometer. This system will handle a beam of approx. 3 million particles per second and have a resolution of 200 μm. A summary of the status of the chambers and the custom integrated circuits is presented. The data acquisition system is described. Prototype chambers have been built and tested with results that are consistent with the expected chamber properties

  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

    2015-11-01

    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. PMID:26492154

  12. Vacuum chamber of the injector synchrotron for the Advanced Photon Source

    International Nuclear Information System (INIS)

    The 40 chambers of the 368 m, 7-GeV injector synchrotron of the Advanced Photon Source are made from 1 mm-thick, 316LN stainless steel tubing. Tubes are cold-drawn to an elliptical shape with inside major and minor axes of 6 cm and 3.7 cm, respectively. This results in a thin metallic chamber without corrugations, which allows maximum beam space in the magnets and withstands atmospheric pressure. Sections of the chamber are bent to match the radius of curvature (33.3 m) of the beam over the entire effective length of the dipole magnets. A modified orbital welder is used to join sections of tubing. The chambers and the pumping system required to achieve a pressure of 10-9 Torr are described. A straight section of chamber tubing was tested under external pressure up to 60 psig. At 15 psig, the resulting deflection at the minor half axis was 0.2mm and a maximum compressive stress of 13,500 psi was measured. Tube deformation remained in the elastic region up to ∼38 psig. 4 refs., 2 figs

  13. 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)

  14. Atmospheric Smell

    DEFF Research Database (Denmark)

    Stenslund, Anette

    awareness. Subsequently, visitor interviews revealed how a museum-staged hospital atmosphere of an art installation was directly addressed owing to its smell. Curiously, this observation speaks against prevailing literature portraying smell as the ‘mute sense’, and what is more, the museum display did not...... alter smell curatorially. Rather, smell was gestured through non-olfactory effects and it was put in words metonymically, gesturing a reversibly synaesthetic atmosphere of a hospital. Visitor conversations revealed how smell could be poignantly picked up in situ, yet not until frequenting the museum...

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

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C. [Queen' s Univ., Kingston, ON (Canada). et al.

    2015-10-26

    We reported new data from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF3I 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 C3F8 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. We found 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 interacting with iodine nuclei is ruled out.

  16. Dark matter search results from the PICO-60 CF3I bubble chamber

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C.; Asner, David M.; Ardid, 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.; Fallows, S.; Farine, J.; Felis, I.; Filgas, R.; Girard, F.; Giroux, G.; Grandison, A.; Hai, M.; Hall, Jeter C.; Harris, O.; Jin, M.; Krauss, C. B.; Lafreniere, M.; Laurin, M.; Lawson, I.; Levine, I.; Lippincott, W. H.; Mann, E.; Maurya, D.; Mitra, Pitam; 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, Andrew; Stekl, I.; Vazquez Jauregui, Eric; Wells, J.; Wichoski, U.; Zacek, V.; Zhang, J.; Shkrob, Ilya A.

    2016-03-28

    New data are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF3I 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 livedays, 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 C3F8 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 weakly interacting massive particles interacting via spin-dependent proton and spin-independent processes are set, and most interpretations of the DAMA/LIBRA modulation signal as dark matter interacting with iodine nuclei are ruled out.

  17. Dark matter search results from the PICO-60 CF3 I bubble chamber

    Science.gov (United States)

    Amole, C.; Ardid, M.; 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.; Fallows, S.; Farine, J.; Felis, I.; Filgas, R.; Girard, F.; Giroux, G.; Grandison, A.; Hai, M.; Hall, J.; Harris, O.; Jin, M.; Krauss, C. B.; 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.; Vázquez-Jáuregui, E.; Wells, J.; Wichoski, U.; Zacek, V.; Zhang, J.; Shkrob, I. A.; PICO Collaboration

    2016-03-01

    New data are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF3 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 livedays, 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 C3 F8 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 weakly interacting massive particles interacting via spin-dependent proton and spin-independent processes are set, and most interpretations of the DAMA/LIBRA modulation signal as dark matter interacting with iodine nuclei are ruled out.

  18. 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.

  19. 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...

  20. Investigation on Atmospheric Corrosiveness in Hainan Province

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    According to the results of four-year exposure tests for carbon steel samples in Hainan province, the influences of meteorological factors and Cl- on atmospheric corrosion were investigated. The feature of atmospheric corrosion in this area was summarized. A corrosive map for the area was drawn. The corrosion products on carbon steel at some typical places were analyzed by XRD and XPS.

  1. Technical Note: New methodology for measuring viscosities in small volumes characteristic of environmental chamber particle samples

    OpenAIRE

    L. Renbaum-Wolff; J. W. Grayson; A. K. Bertram

    2012-01-01

    Herein, a method for the determination of viscosities of small sample volumes is introduced, with important implications for the viscosity determination of particle samples from environmental chambers (used to simulate atmospheric conditions). The amount of sample needed is < 1 μl, and the technique is capable of determining viscosities (η) ranging between 10−3 and 103 Pascal seconds (Pa s) in samples that cover a range of chemic...

  2. Technical Note: New methodology for measuring viscosities in small volumes characteristic of environmental chamber particle samples

    OpenAIRE

    L. Renbaum-Wolff; J. W. Grayson; A. K. Bertram

    2013-01-01

    Herein, a method for the determination of viscosities of small sample volumes is introduced, with important implications for the viscosity determination of particle samples from environmental chambers (used to simulate atmospheric conditions). The amount of sample needed is < 1 μl, and the technique is capable of determining viscosities (η) ranging between 10−3 and 103 Pascal seconds (Pa s) in samples that cover a range of chemical properties a...

  3. Control of out-of-furnace ecologically safe metallothermic smelting in a hermetic chamber

    Science.gov (United States)

    Ovsov, N. S.; Eliseev, Yu. E.; Bogdanov, C. V.

    2014-12-01

    To create a low-vacuum atmosphere and excess pressure in a hermetic melting chamber is shown to be useful for block smelting. The results of combined control of the smelting process by changing the pressure of the gases released from a crucible in melting a metal in the reactor-autoclave regime are presented. These results are used to provide ecologically safe conditions for the production of ingots 1.5-2 t in weight.

  4. Automated correction on X-rays calibration using transmission chamber and LabVIEWTM

    International Nuclear Information System (INIS)

    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 LabVIEWTM 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 LabVIEWTM 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)

  5. Measurement of air kerma rate for Cs-137 using different ionization chambers

    International Nuclear Information System (INIS)

    Due to the importance of radiation doses in medical field quality assurance should be established in order to maintain a reasonable balance between the purpose of application and exposure. This study had been carried out to achieve quality control for protection based on air kerma rate. Measurements were performed by using Cs-137 for the comparison of two working ionization chambers in secondary standard dosimetry laboratory of Sudan. Spherical ionization chamber L S-01 1000 cc S/N 912 and Farmer ionization chamber 2675 A 600 cc S/N 0511, respectively. The results obtained from this study have been represented as mean and their standard deviations shown in most cases remains at 5% uncertainly. Comparison between kinetic energy released per unit mass in air rate (air kerma rate) were obtained by using spherical ionization chamber L S-01 1000 cc S/N 912 and results have been determined using inverse square law. The differences have been represented as means and standard deviations with significant P-value less than 0.05. Spherical ionization chamber gives accurate, reproducible results with acceptable uncertainty which is more suitable for calibration of radiation detectors.(Author)

  6. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    . As a response to this situation, our design artefact, the interactive furniture Kidkit, invites children to become accustomed to the alarming sounds sampled from the ward while they are waiting in the waiting room. Our design acknowledges how atmospheres emerge as temporal negotiations between the...

  7. 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.

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

    International Nuclear Information System (INIS)

    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

  9. The cloud chamber and its metamorphoses

    International Nuclear Information System (INIS)

    The stunning invention of the Wilson chamber in 1911 stayed almost ignored by the physicist community for more than a decade although it permitted the visualization of the track of an alpha particle as soon as 1911. The detection principle is based on the expansion of a saturated vapor that allows the visualization of a ionizing particle motion through the formation of droplets around the ions created all along the particle path. The original device was too slow (only one expansion per minute) to be used for the detection of rare events unless to operate it for months or years. A decisive step was made in the beginning of the twenties by the Japanese physicist Takeo Shimizu, working at the Cavendish Laboratory. He managed to automate the Wilson chamber and to equip it with 2 mirrors and a camera. This new generation allowed 5 expansion per second and the knowledge of the particle track orientation in space thanks to a simultaneous photography following 2 perpendicular directions. A rate of 4 shots a minute was achieved. The Wilson chamber was constantly improved during its 30 years long career and was only supplanted by the bubble chamber in the fifties. (A.C.)

  10. Progress in timing Resistive Plate Chambers

    OpenAIRE

    Blanco, A.; Carolino, N.; Correia, C. M. B. A.; Ferreira-Marques, R.; P. Fonte(LIP-Laboratório de Instrumentação e Física Experimental de Partículas, Portugal); Gobbi, A.; González-Díaz, D.; Lopes, M.I.; Lopes, L.; Macedo, M. P.; Mangiarotti, A.; V. Peskov; Policarpo, A.

    2004-01-01

    Timing RPCs are Resistive Plate Chambers made with glass and metal electrodes separated by precision spacers. Typical gas gaps are a few hundred micrometers wide. Such counters were introduced in 1999 and have since reached timing accuracies below 50 ps [sigma] with efficiencies above 99% for MIPs. Applications in high-energy physics have already taken place with several more under study.

  11. Anterior Chamber Live Loa loa: Case Report.

    Science.gov (United States)

    Kagmeni, G; Cheuteu, R; Bilong, Y; Wiedemann, P

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis. PMID:27441005

  12. Detecting dark matter with scintillating bubble chambers

    Science.gov (United States)

    Zhang, Jianjie; Dahl, C. Eric; Jin, Miaotianzi; Baxter, Daniel

    2016-03-01

    Threshold based direct WIMP dark matter detectors such as the superheated bubble chambers developed by the PICO experiment have demonstrated excellent electron-recoil and alpha discrimination, excellent scalability, ease of change of target fluid, and low cost. However, the nuclear-recoil like backgrounds have been a limiting factor in their dark matter sensitivity. We present a new type of detector, the scintillating bubble chamber, which reads out the scintillation pulse of the scattering events as well as the pressure, temperature, acoustic traces, and bubble images as a conventional bubble chamber does. The event energy provides additional handle to discriminate against the nuclear-recoil like backgrounds. Liquid xenon is chosen as the target fluid in our prototyping detector for its high scintillation yield and suitable vapor pressure which simplifies detector complexity. The detector can be used as an R&D tool to study the backgrounds present in the current PICO bubble chambers or as a prototype for standalone dark matter detectors in the future. Supported by DOE Grant DE-SC0012161.

  13. Anterior Chamber Live Loa loa: Case Report

    Science.gov (United States)

    Kagmeni, G.; Cheuteu, R.; Bilong, Y.; Wiedemann, P.

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis. PMID:27441005

  14. Opposite expansion system of fast bubble chambers

    International Nuclear Information System (INIS)

    Pneumatic opposite expansion system, operating on frequency up to 100 Hz and minimal cycle duration up to 3 ms, is created for accomplishingh expansion working cycle of a precision liquid-hydrogen fast bubble chamber. Fast-action hydraulic servo slide valves with electric control are used as command and control elements

  15. Vacuum chamber for intersection I-4

    CERN Multimedia

    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.

  16. A double grid position sensitive avalanche chamber

    International Nuclear Information System (INIS)

    A double grid position sensitive avalanche chamber (DGAC) has been developed. Its sensitive area is 250 x 200 mm2. The properties of the DGAC were tested in flowing isobutylene gas at a pressure of 360 Pa. The position resolution of 4 mm in both x and y coordinates and the time resolution of 290 ps are obtained for 252Cf fission fragment source

  17. 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.

  18. The FTU (Frascati Tokamak Upgrade) vacuum chamber

    International Nuclear Information System (INIS)

    The FTU vacuum vassel has been designed to withstand high electromagnetic and thermal loads and to reach high vacuum conditions which are essential to obtain clean, impurity free plasma. After a survey of the vacuum chamber requirements and of the design development, the paper reports the main manufactoring process such as welding, stress relieving, machining, nondestructive testing, outgassing and preassembly

  19. Chamber transport for heavy ion fusion

    International Nuclear Information System (INIS)

    A brief review is given of research on chamber transport for HIF (heavy ion fusion) dating from the first HIF Workshop in 1976 to the present. Chamber transport modes are categorized into ballistic transport modes and channel-like modes. Four major HIF reactor studies are summarized (HIBALL-II, HYLIFE-II, Prometheus-H, OSIRIS), with emphasis on the chamber transport environment. In general, many beams are used to provide the required symmetry and to permit focusing to the required small spots. Target parameters are then discussed, with a summary of the individual heavy ion beam parameters required for HIF. The beam parameters are then classified as to their line charge density and perveance, with special emphasis on the perveance limits for radial space charge spreading, for the space charge limiting current, and for the magnetic (Alfven) limiting current. The major experiments on ballistic transport (SFFE, Sabre beamlets, GAMBLE II, NTX, NDCX) are summarized, with specific reference to the axial electron trapping limit for charge neutralization. The major experiments on channel-like transport (GAMBLE II channel, GAMBLE II self-pinch, LBNL channels, GSI channels) are discussed. The status of current research on HIF chamber transport is summarized, and the value of future NDCX-II transport experiments for the future of HIF is noted

  20. Acoustical-Levitation Chamber for Metallurgy

    Science.gov (United States)

    Barmatz, M. B.; Trinh, E.; Wang, T. G.; Elleman, D. D.; Jacobi, N.

    1983-01-01

    Sample moved to different positions for heating and quenching. Acoustical levitation chamber selectively excited in fundamental and second-harmonic longitudinal modes to hold sample at one of three stable postions: A, B, or C. Levitated object quickly moved from one of these positions to another by changing modes. Object rapidly quenched at A or C after heating in furnace region at B.