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Sample records for open-top chamber experiment

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

    NASA Astrophysics Data System (ADS)

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

    A field experiment in open-top chambers (OTCs) was performed to quantitatively assess the growth and yield response of potato to discontinuous exposures to atmospheric ethylene (200, 400 and 800 ppb, applied twice weekly and 200 and 400 ppb applied 4 times weekly, each for 3 h/event). To evaluate the effect of ethylene on potato tuber yield, a module was developed for an existing crop growth simulation model by incorporating the effects of ethylene on epinasty and photosynthesis. Explorations with the model showed that in a worst case scenario, ethylene-induced epinasty had only a marginal effect on tuber yield. Short-term exposures to ethylene under laboratory conditions inhibited photosynthesis, but it recovered within 48 h. When exposed to ethylene for longer than 12 h, irreversible damage of the photosynthesis apparatus occurred. Exposure to ethylene in the OTCs resulted in epinasty and reduced flowering. The number of flowers on potato decreased with increasing concentrations of ethylene, irrespective of the exposure frequency. Calculations showed that the number of flowers was significantly reduced at ca. 170 ppb ethylene, averaged over the hours of exposure. Ethylene concentrations up to 800 ppb, administered 4 times weekly for 3 h during the growing season, did not affect vegetative growth and yield in fumigated potatoes. Under these experimental conditions, the modified simulation model incorporating the effects of ethylene on epinasty and photosynthesis forecasts a 5% effect on tuber yield at concentrations of 1600 ppb. All results indicate that ethylene concentrations higher than 800 ppb are required to adversely affect tuber yield of potato.

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

    USDA-ARS?s Scientific Manuscript database

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

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

    PubMed

    Gerosa, G; Marzuoli, R; Desotgiu, R; Bussotti, F; Ballarin-Denti, A

    2008-03-01

    An Open-Top Chambers experiment on Fagus sylvatica and Quercus robur seedlings was conducted in order to compare the performance of an exposure-based (AOT40) and a flux-based approaches in predicting the appearance of ozone visible injuries on leaves. Three different ozone treatments (charcoal-filtered; non-filtered; and open plots) and two soil moisture treatments (watered and non-watered plots) were performed. A Jarvisian stomatal conductance model was drawn up and parameterised for both species and typical South Alpine environmental conditions, thus allowing the calculation of ozone stomatal fluxes for every treatment. A critical ozone flux level for the onset of leaf visible injury in beech was clearly identified between 32.6 and 33.6 mmolO3 m(-2). In contrast, it was not possible to identify an exposure critical level using the AOT40 index. Water stress delayed the onset of the leaf visible injuries, but the flux-based approach was able to take it into account accurately.

  4. Assessment of yield losses in tropical wheat using open top chambers

    NASA Astrophysics Data System (ADS)

    Rai, R.; Agrawal, M.; Agrawal, S. B.

    The present study deals with the evaluation of effects of ambient gaseous air pollution on wheat ( Triticum aestivum L. var. HUW-234) growing in a suburban area situated in eastern Gangetic plain of India, using open top chambers. Eight hourly air monitoring was conducted for ambient concentrations of SO 2, NO 2 and O 3 in filtered chambers (FCs), non-filtered chambers (NFCs) and open plots (OPs). Various morphological, physiological and biochemical parameters were assessed during different developmental stages and finally yield parameters were quantified at the time of harvest. Mean concentrations of SO 2, NO 2 and O 3 were 8.4, 39.9 and 40.1 ppb, respectively during the experiment in NFCs. Concentrations of SO 2, NO 2 and O 3 reduced by 74.6%, 84.7% and 90.4%, respectively in FCs as compared to NFCs. Plants grown in FCs showed higher photosynthetic rate, stomatal conductance, chlorophyll content and Fv/Fm ratio as compared to the plants in NFCs and OPs. Lipid peroxidation, proline, total phenol and ascorbic acid contents and peroxidase activity were higher in plants grown in NFCs. There were improvements in morphological parameters of plants growing in FCs as compared to those in NFCs and OPs. Yield of plants also increased significantly in FCs as compared to those ventilated with ambient air (NFCs) or grown in OPs. During the vegetative phase, NO 2 concentrations were higher than O 3, but O 3 became dominant pollutant during the time of grain setting and filling. The study concludes that O 3 and NO 2 are the main air pollutants in the sub-urban areas causing significant yield reductions in tropical wheat plants.

  5. Determination of acidic gas and particle concentrations in open-top field chambers. Final report

    SciTech Connect

    Bytnerowicz, A.

    1993-06-01

    The report describes determinations of concentrations of gaseous and particulate air pollutants in open-top field chambers used for exposing of tree seedlings to acidic rain and ozone. During the study, air pollution concentrations were measured in the following types of chambers: charcoal-filtered (control); ambient air with ambient ozone concentrations; ambient air with double ambient ozone concentrations. Concentrations of gaseous nitric acid, gaseous nitrous acid, ammonia, sulfur dioxide and nitrate, ammonium and sulfate in fine and coarse particulate fractions were determined. Increased concentrations of nitric acid were detected in chambers due to the generation of ozone, however, these concentrations were lower than the ambient concentrations measured in outside plots. Elevated concentrations of nitrous acid were detected in the charcoal-filtered chambers.

  6. Sampling open-top chambers and plantations for live fine-root biomass of loblolly pine. Forest Service research note

    SciTech Connect

    Zarnoch, S.J.; Marx, D.H.; Ruehle, J.L.; Baldwin, V.C.

    1993-09-08

    A soil-core sampling protocol was developed for estimating the standing crop of live fine-root biomass in young loblolly pines (Pinus taeda L.). Some of the pines were in ozone experiments in open-top chambers. Others were in young plantations. Attempts were made to find strata that would reduce the variability of estimates. With the pilot study estimates of variability, sampling designs were developed to meet specified criteria of precision. Estimates of fine-root biomass based on three soil-core sizes increased monotonically with core size.

  7. [Effects of elevated ozone on Pinus armandii growth: a simulation study with open-top chamber].

    PubMed

    Liu, Chang-Fu; Liu, Chen; He, Xing-Yuan; Ruan, Ya-Nan; Xu, Sheng; Chen, Zhen-Ju; Peng, Jun-Jie; Li, Teng

    2013-10-01

    By using open-top chamber (OTC) and the techniques of dendrochronology, this paper studied the growth of Pinus armandii under elevated ozone, and explored the evolution dynamics and adaptation mechanisms of typical forest ecosystems to ozone enrichment. Elevated ozone inhibited the stem growth of P. armandii significantly, with the annual growth of the stem length and diameter reduced by 35.0% and 12.9%, respectively. The annual growth of tree-ring width and the annual ring cells number decreased by 11.5% and 54.1%, respectively, but no significant change was observed in the diameter of tracheid. At regional scale, the fluctuation of ozone concentration showed significant correlation with the variation of local vegetation growth (NDVI).

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Indirect prediction of surface ozone concentration by plant growth responses in East Asia using mini-open top chambers.

    PubMed

    Kohno, Yoshihisa; Matsumura, Hideyuki; Miwa, Makoto; Yonekura, Tetsushi; Aihara, Keiji; Umponstira, Chanin; Le, Vo Thanh; Ngoc, Nguyen Thuy; Viet, Phanm Hung; Wei, Ma

    2013-03-01

    We developed small and mobile open top chambers (mini-OTC) measuring 0.6 m (W) × 0.6 m (D) × 1.2 m (H) with an air duct of 0.6 m (W) × 0.23 m (D) × 1.2 m (H). The air duct can be filled with activated charcoal to blow charcoal filtered air (CF) into the chamber, as opposed to non-filtered ambient air (NF). Ozone sensitive radish Raphanus sativus cv. Red Chime and rosette pakchoi Brassica campestris var. rosularis cv. ATU171 were exposed to NF and CF in mini-OTCs at different locations in East Asia. A total of 29 exposure experiments were conducted at nine locations, Shanghai, China, Ha Noi, Vietnam, Lampang, Phitsanulok and Pathumtani, Thailand, and Hiratsuka, Kisai, Abiko and Akagi, Japan. Although no significant relationships between the mean concentrations of ambient O(3) during the experimental period and the growth responses were observed for either species, multiple linear regression analysis suggested a good relationship between the biomass responses in each species and the O(3) concentration, temperature, and relative humidity. The cumulative daily mean O(3) (ppb/day) could be indirectly predicted by NF/CF based on the dry weight ratio of biomass, mean air temperature, and relative air humidity.

  10. Variable temperature effects of Open Top Chambers at polar and alpine sites explained by irradiance and snow depth.

    PubMed

    Bokhorst, Stef; Huiskes, Ad; Aerts, Rien; Convey, Peter; Cooper, Elisabeth J; Dalen, Linda; Erschbamer, Brigitta; Gudmundsson, Jón; Hofgaard, Annika; Hollister, Robert D; Johnstone, Jill; Jónsdóttir, Ingibjörg S; Lebouvier, Marc; Van de Vijver, Bart; Wahren, Carl-Henrik; Dorrepaal, Ellen

    2013-01-01

    Environmental manipulation studies are integral to determining biological consequences of climate warming. Open Top Chambers (OTCs) have been widely used to assess summer warming effects on terrestrial biota, with their effects during other seasons normally being given less attention even though chambers are often deployed year-round. In addition, their effects on temperature extremes and freeze-thaw events are poorly documented. To provide robust documentation of the microclimatic influences of OTCs throughout the year, we analysed temperature data from 20 studies distributed across polar and alpine regions. The effects of OTCs on mean temperature showed a large range (-0.9 to 2.1 °C) throughout the year, but did not differ significantly between studies. Increases in mean monthly and diurnal temperature were strongly related (R(2)  = 0.70) with irradiance, indicating that PAR can be used to predict the mean warming effect of OTCs. Deeper snow trapped in OTCs also induced higher temperatures at soil/vegetation level. OTC-induced changes in the frequency of freeze-thaw events included an increase in autumn and decreases in spring and summer. Frequency of high-temperature events in OTCs increased in spring, summer and autumn compared with non-manipulated control plots. Frequency of low-temperature events was reduced by deeper snow accumulation and higher mean temperatures. The strong interactions identified between aspects of ambient environmental conditions and effects of OTCs suggest that a detailed knowledge of snow depth, temperature and irradiance levels enables us to predict how OTCs will modify the microclimate at a particular site and season. Such predictive power allows a better mechanistic understanding of observed biotic response to experimental warming studies and for more informed design of future experiments. However, a need remains to quantify OTC effects on water availability and wind speed (affecting, for example, drying rates and water stress

  11. Ozone deposition to an oat crop ( Avena sativa L.) grown in open-top chambers and in the ambient air

    NASA Astrophysics Data System (ADS)

    Pleijel, H.; Wallin, G.; Karlsson, P. E.; Skarby, L.; Sellden, G.

    Fluxes and deposition velocities for ozone were determined for open-top chambers with and without an oat crop, and for the adjacent field, using a resistance analogue model and the aerodynamic wind-profile method, respectively. During a period when the canopy was green and the ambient wind speeds modest, the fluxes and deposition velocities were higher in the chamber with plants than in the field crop. The deposition to chamber walls and soil in the chamber only accounted for part of that difference. The deposition velocity for ozone to the crop was light-dependent both in the chamber with plants and in the ambient air. With increasing plant senescence, the deposition velocity declined and the light dependence disappeared. Fluctuations in deposition velocity superimposed on the overall declining trend followed the same temporal pattern in the chambers with and without plants. These fluctuations in deposition velocity may partly be explained by variations in surface wetness. Differences in boundary layer conductance between chamber and ambient, which under certain conditions may significantly influence the validity of the chamber as a test system, were observed.

  12. Evaluation of ambient air pollution impact on carrot plants at a suburban site using open top chambers.

    PubMed

    Tiwari, S; Agrawal, M; Marshall, F M

    2006-08-01

    The present experiment was done to evaluate the impact of ambient air pollution on carrot (Dacus carota var. Pusa Kesar) plants using open top chambers (OTCs) ventilated with ambient (NFCs) or charcoal filtered air (FCs) at a suburban site of Varanasi, India. Various morphological, physiological and biochemical characteristics of the plants were studied at different growth stages. Air monitoring data clearly showed high concentrations of SO2, NO2 and O3 in the ambient air of study site. SO2 and NO2 concentrations were higher during early growth stages of carrot, whereas O3 concentration was highest during later growth stages. Filtration of air has caused significant reductions in all the three pollutant concentrations in FCs as compared to NFCs. Plants growing in FCs showed significantly higher photosynthetic rate, stomatal conductance, water use efficiency and variable fluorescence as compared to plants growing in NFCs. Protein content also showed a similar pattern, however, lipid peroxidation, ascorbic acid content and peroxidase activity were higher in plants growing in NFCs as compared to FCs. Shoot length, number of leaves per plant, leaf area and root and shoot weight increased significantly upon filtration of ambient air. Total nitrogen decreased significantly in root, but increased significantly in shoot of plants grown in NFCs. Total P, Mg, Ca and K contents decreased significantly in plants grown in NFCs as compared to FCs. The individual pollutant concentrations were below threshold for plant injury, but the combined effect of all the three seems to act synergistically in causing greater adverse impact on dry weight and physiology of carrot plants. The study clearly indicates that air pollutants are high enough in the ambient air to cause significant unfavorable impact on carrot plants. The work further supports the usefulness of OTCs for assessing air pollution damage under field conditions in developing countries.

  13. Screen-aided CO 2 control (SACC): a middle ground between FACE and open-top chambers

    NASA Astrophysics Data System (ADS)

    Leadley, P. W.; Niklaus, P.; Stocker, R.; Körner, Ch.

    We have developed a novel CO 2 exposure system for natural vegetation that is a middle ground between Free Air CO 2 Enrichment (FACE) and traditional open-top chambers (OTC). Screen-Aided CO 2 Control (SACC) technology uses much less CO 2 per experiment and per replicate than FACE and is superior to OTCs in terms of its effects on microclimate. A SACC unit consists of a thin metal frame, a clear plastic "screen", and a pipe at the base of the screen through which CO 2 enriched jets of air are directed into the unit. There is a gap between the ground and the bottom of the pipe and the screen is relatively short in comparison to the maximum height of the vegetation. Our SACC units are hexagonal and enclose a ground area of 1.27 m 2. SACC works in the following way: 1) the screen breaks the wind and creates turbulent mixing within the unit, 2) the mixing of the outside air with the CO 2 enriched jets of air generates relatively uniform CO 2 concentrations within the screened-in vegetation, and 3) a fully automated system monitors CO 2 concentrations and adjusts CO 2 injection rates for each unit every ca. 10 minutes to maintain preset CO 2 concentrations. Twenty-four hour means of CO 2 concentrations in the middle of a unit are typically maintained within 1 μl l -1 of their set points. Spatial variation and short-term fluctuations in CO 2 concentration are similar to those in OTCs and FACE. CO 2 consumption at our site is 5 kg CO 2 day -1 replicate -1 for a total of ca. 30 tons per year for 20 elevated CO 2 SACC units. Compared to OTCs, SACC units have reduced temperature peaks at full sunlight, minimal effects on solar radiation, reduced rainfall interception by chamber walls, and freer access of small animals to experimental plots. We believe that SACC is the best method for exposing short stature vegetation to elevated CO 2 when financial constraints do not allow for a properly replicated FACE experiment.

  14. Effect of elevated atmospheric carbon dioxide and open-top chambers on transpiration in a tallgrass prairie

    SciTech Connect

    Bremer, D.J.; Ham, J.M.; Owensby, C.E.

    1996-07-01

    Increasing concentrations of atmospheric carbon dioxide (CO{sub 2}) may influence plant-water relations in natural and agricultural ecosystems. A tallgrass prairie near Manhattan, KS, was exposed to elevated atmospheric CO{sub 2} using open-top chambers (OTCs). Heat balance sap flow gauges were used to measure transpiration in ironweed [Vernonia baldwini var. interior (Small) Schub.], aC{sub 3}forb, and on individual grass culms of big bluestem (Andropogan geradii Vitman) and indiangrass [Sorghastrum nutans (L>) Nash], both C{sub 4} grasses, in each of three treatments: (1) CE (chamber enriched, 2x ambient CO{sub 2}); (2) CA (chamber ambient, no CO{sub 2} enrichment); and (3) NC (no chamber, no CO{sub 2} enrichment). Sap flow data were coupled with measurements of stomatal conductance, plant/canopy resistance, and whole-chamber evapotranspiration (ET) to determine the effect of elevated CO{sub 2} on water use at different scales. Because of frequent rainfall during the study, all data were collected under well-watered conditions. Comparisons of CE and CA showed that sap flow was reduced by 33% in ironweed, 18% in big bluestem, and 22% in indiangrass under CO{sub 2} enrichment. Whole-chamber ET was reduced by 23 to 27% under CO{sub 2} enrichment. Comparisons of CA and NC showed that the environmental effect of the OTCs caused a 21 to 24% reduction in transpiration. Stomatal conductance decreased from 7.9 to 3.6 mm s{sup {minus}1} in big bluestem and from 5.3 to 3.2 mm s{sup {minus}1} in indiangrass under CO{sub 2} enrichment. Soil water was consistently highest under elevated CO{sub 2}, reflecting the large reductions in transpiration. During sap flow measurements, whole-plant stomatal resistance to water vapor flux in big bluestem increased from 103 to 194 s m{sup {minus}1} under elevated CO{sub 2}. 23 refs., 7 figs., 4 tabs.

  15. Effects of elevated CO2 and N fertilization on soil respiration from ponderosa pine (Pine ponderosa) in open-top chambers

    Treesearch

    James M. Vose; Katherine J. Elliott; Dale W. Johnson; Roger F. Walker; Mark G. Johnson; David T. Tingey

    1995-01-01

    We measured growing season soil CO2 evolution under elevated atmospheric CO2 and soil nitrogen (N) additions. Our objectives were to determine treatment effects, quantify seasonal variation, and determine regulating mechanisms. Elevated CO2 treatments were applied in open-top chambers containing 3-...

  16. Limitations to soybean photosynthesis at elevated carbon dioxide in free-air enrichment and open top chamber systems.

    PubMed

    Bunce, James A

    2014-09-01

    It has been suggested that the stimulation of soybean photosynthesis by elevated CO2 was less in free-air carbon dioxide enrichment (FACE) systems than in open top chambers (OTC), which might explain smaller yield increases at elevated CO2 in FACE systems. However, this has not been tested using the same cultivars grown in the same location. I tested whether soybean photosynthesis at high light and elevated CO2 (ambient+180 μmol mol(-1)) was limited by electron transport (J) in FACE systems but by ribulose-bisphosphate carboxylation capacity (VCmax) in OTC. FACE systems with daytime and continuous CO2 enrichment were also compared. The results indicated that in both cultivars examined, midday photosynthesis at high light was always limited by VCmax, both in the FACE and in the OTC systems. Daytime only CO2 enrichment did not affect photosynthetic parameters or limitations, but did result in significantly smaller yields in both cultivars than continuous elevation. Photosynthesis measured at low photosynthetic photon flux density (PPFD) was not higher at elevated than at ambient CO2, because of an acclimation to elevated CO2 which was only evident at low measurement PPFDs.

  17. Flower evolution of alpine forbs in the open top chambers (OTCs) from the Qinghai-Tibet Plateau

    PubMed Central

    Zhang, Chan; Wang, Lin-Lin; Yang, Yong-Ping; Duan, Yuan-Wen

    2015-01-01

    Effects of global changes on biodiversity have been paid more and more attention world widely, and the open top chambers (OTCs) are the most common tools to study the effects of climatic warming on plant diversity. However, it remains unclear how flowers evolve under environmental changes, which could help us to understand the changes of plant diversity in the OTCs. We compared the insect diversity and pollen:ovule (P/O) ratio of eight outcrossing species with different life histories inside and outside the OTCs on the Qinghai-Tibet Plateau, to examine the effects induced by OTCs on the evolution of floral traits. In the OTCs, P/O ratio decreased in annuals, but increased in perennials, indicating an overall trend toward selfing in annuals. We found that the insect diversity differed significantly inside and outside the OTCS, with decreases of dipteran insects and bees. We concluded that changes of P/O ratio in the studied plant species might result from pollination failure, which might be the results of mismatch between flowering time and pollinator activities. We also suggested annuals might be in a more extinction risk than perennials in OTCs, if strong inbreeding depression occurs in these annual outcrossing plants. PMID:25998558

  18. Flower evolution of alpine forbs in the open top chambers (OTCs) from the Qinghai-Tibet Plateau.

    PubMed

    Zhang, Chan; Wang, Lin-Lin; Yang, Yong-Ping; Duan, Yuan-Wen

    2015-05-22

    Effects of global changes on biodiversity have been paid more and more attention world widely, and the open top chambers (OTCs) are the most common tools to study the effects of climatic warming on plant diversity. However, it remains unclear how flowers evolve under environmental changes, which could help us to understand the changes of plant diversity in the OTCs. We compared the insect diversity and pollen:ovule (P/O) ratio of eight outcrossing species with different life histories inside and outside the OTCs on the Qinghai-Tibet Plateau, to examine the effects induced by OTCs on the evolution of floral traits. In the OTCs, P/O ratio decreased in annuals, but increased in perennials, indicating an overall trend toward selfing in annuals. We found that the insect diversity differed significantly inside and outside the OTCS, with decreases of dipteran insects and bees. We concluded that changes of P/O ratio in the studied plant species might result from pollination failure, which might be the results of mismatch between flowering time and pollinator activities. We also suggested annuals might be in a more extinction risk than perennials in OTCs, if strong inbreeding depression occurs in these annual outcrossing plants.

  19. Whole System Carbon Exchange of Small Stands of Pinus Ponderosa Growing at Different CO{sub 2} concentrations in open top chambers

    SciTech Connect

    Ball, J. Timothy; Ross, Peter D.; Picone, John B.; Eichelmann, Hillar Y.; Ross, Gregory N.

    1996-12-01

    Functional understanding of the carbon cycle from the molecular to the global level is a high scientific priority requiring explanation of the relationship between fluxes at different spatial and temporal scales. We describe methods used to convert an open top chamber into both closed and open flow gas exchange systems utilized to measure such fluxes. The systems described consist of temporary modifications to an open top chamber, and are put in place for several days on one or several open top chambers. In the closed system approach, a chamber is quickly sealed for a short, predetermined time interval, the change in gas concentrations is measured, then the chamber is unsealed and ventilated. In the open flow system approach, airflow into the open top chamber is measured by trace gas injection, and the air stream concentration of CO{sub 2} and water vapor is measured before and after injection into the chamber. The closed chamber approach can resolve smaller fluxes, but causes transient increases in chamber air temperature, and has a high labor requirement. The open flow approach reduces the deviation of measuring conditions from ambient, may be semi-automated (requiring less labor), allows a more frequent sampling interval, but cannot resolve low fluxes well. Data demonstrating the capabilities of these systems show that, in open canopies of ponderosa pine, scaling fluxes from leaves to whole canopies is well approximated from summation of leaf P{sub s} rates. Flux measurements obtained from these systems can be a valuable contribution to our understanding whole system material fluxes, and challenge our understanding of ecosystem carbon budgets.

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

    PubMed

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

    2017-08-01

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

  1. The combined effects of CO2 concentration and solar UV-B radiation on faba bean grown in open-top chambers.

    PubMed

    Visser, A J; Tosserams, M; Groen, M W; Magendans, G W; Rozema, J

    1997-01-01

    The response of faba bean seedlings to the combined effects of increased atmospheric CO2 concentrations ([CO2]) and solar UV-B irradiance was studied using open-top chambers transparent to UV-B radiation. The purpose of the study was to determine whether effects of increased [CO2] on growth and physiology are modified by the present solar UV-B fluence rate in the Netherlands. Seedlings were exposed to 350 or 700 micromoles mol-1 CO2. At both [CO2], solar UV-B irradiance was either present or reduced using polyester foil opaque to UV-B radiation. To obtain information on the time dependence of increased [CO2] and UV-B radiation effects, three harvests were performed during the experiment. CO2 enrichment resulted in increased biomass production at all harvests. At the final harvest, UV-B radiation did not affect biomass production but a significant decrease was observed after 14 d of treatment. A reduction of the UV-B fluence increased shoot length at both [CO2] throughout the experiment. UV-B radiation slightly altered biomass allocation. Plants grown at reduced levels of UV-B radiation invested less biomass in flowers and more in stem material compared to plants grown at ambient UV-B levels. CO2 enrichment resulted in a stimulation of net photosynthesis after 26 and 38 d of treatment. UV-B reduction did not alter this response. After 26 d of treatment, photosynthetic acclimation to CO2 enrichment was observed, which was probably the result of accumulation of carbohydrates in the leaves. After 38 d, photosynthetic acclimation was no longer present. The UV absorbance of methanolic leaf extracts was increased by CO2 enrichment only. Both CO2 enrichment and solar UV-B reduced the transmittance of radiation through intact attached leaves. Interaction between [CO2] and UV-B radiation was limited to UV-A transmittance of leaves. Under prevalent experimental conditions, UV-B radiation did not affect the measured physiological parameters. Most open-top chambers used for

  2. Investigation on High Performance of 10m Semi Anechoic Chamber by using Open-Top Hollow Pyramidal Hybrid EM Wave Absorber

    NASA Astrophysics Data System (ADS)

    Kurihara, Hiroshi; Saito, Toshifumi; Suzuki, Yoshikazu; Nishikata, Atsuhiro; Hashimoto, Osamu

    The emission radiated from electric and electronic equipments is evaluated through OATS. Recently, it is not fully prepared the environment for OATS because of a variety of communication radiation sources (e.g., digital television broadcast and cellular phone station). Therefore, the EM anechoic chambers are becoming more and more important as EMI test site. On the other hand, the EM anechoic chambers are needed high performance in order to cut down EMI countermeasure cost and calculate the antenna factor. The objective of this paper is mainly to present the EM wave absorber design in order to obtain within ±2dB against the theoretical site attenuation values in the 10m semi anechoic chamber at 30MHz to 300MHz. We get the necessary reflectivity of EM wave absorber by the basic site attenuation equation. We design the open-top hollow pyramidal new hybrid EM wave absorber consisted of 180cm long dielectric loss foam and ferrite tiles. Then, we design the 10m semi anechoic chamber by using the ray-tracing simulation and construct it in the size of L24m×W15.2m×H11.2m. More over, we measure the site attenuation of the constructed 10m semi anechoic chamber by using the broadband calculable dipole antennas. As the result, we confirm the validity of the designed open-top hollow pyramidal new hybrid EM wave absorber.

  3. [Open-top Chamber for in situ Research on Response of Mercury Enrichment in Rice to the Rising Gaseous Elemental Mercury in the Atmosphere].

    PubMed

    Chen, Jian; Wang, Zhang-wei; Zhang, Xiao-shan; Qin, Pu-feng; Lu, Hai-jun

    2015-08-01

    In situ research was conducted on the response of mercury enrichment in rice organs to elevated gaseous elemental mercury (GEM) with open-top chambers (OTCs) fumigation experiment and soil Hg enriched experiment. The results showed that Hg concentrations in roots were generally correlated with soil Hg concentrations (R = 0.9988, P < 0.05) but insignificantly correlated with air Hg concentrations (P > 0.05), indicating that Hg in rice roots was mainly from soil. Hg concentrations in stems increased linearly (R(B) = 0.9646, R(U) = 0.9831, P < 0.05) with elevated GEM, and Hg concentrations in upper stems were usually higher than those in bottom stems in OTCs experiment. Hg concentrations in bottom stems were generally correlated with soil Hg concentrations (R = 0.9901, P < 0.05) and second-order polynomial (R = 0.9989, P < 0.05) was fitted for Hg concentrations in upper stems to soil Hg concentrations, and Hg concentrations in bottom stems were usually higher than those in upper stems in soil Hg enriched experiment, indicating the combining impact of Hg from air and soil on the accumulation of mercury in stems. Hg concentrations in foliage were significantly correlated (P < 0.05) with air Hg and linearly correlated with soil Hg (R = 0.9983, P = 0.0585), implying that mercury in foliage was mainly from air and some of Hg in root from soil was transferred to foliage through stem. Based on the function in these filed experiments, it was estimated that at least 60%-94% and 56%-77% of mercury in foliage and upper-stem of rice was from the atmosphere respectively, and yet only 8%-56% of mercury in bottom-stem was attributed to air. Therefore, mercury in rice aboveground biomass was mainly from the atmosphere, and these results will provide theoretical basis for the regional atmospheric mercury budgets and the model of mercury cycling.

  4. Assessing plant response to ambient ozone: growth of young apple trees in open-top chambers and corresponding ambient air plots.

    PubMed

    Manning, W J; Cooley, D R; Tuttle, A F; Frenkel, M A; Bergweiler, C J

    2004-12-01

    Open-top chambers (OTCs) and corresponding ambient air plots (AA) were used to assess the impact of ambient ozone on growth of newly planted apple trees at the Montague Field research center in Amherst, MA. Two-year-old apple trees (Malus domestica Borkh 'Rogers Red McIntosh') were planted in the ground in circular plots. Four of the plots were enclosed with OTCs where incoming air was charcoal-filtered (CF); four were enclosed with OTCs where incoming air was not charcoal-filtered (NF) and four were not enclosed, allowing access to ambient air conditions (AA). Conditions in both CF and NF OTCs resulted in increased tree growth and changed incidence of disease and arthropod pests, compared to trees in AA. As a result, we were not able to use the OTC method to assess the impact of ambient ozone on growth of young apple trees in Amherst, MA.

  5. Effects of Tree Canopy Structure and Understory Vegetation on the Effectiveness of Open-Top-Chamber in Manipulating Boreal Forest Microclimate

    NASA Astrophysics Data System (ADS)

    Teuber, L. M.; Nilsson, M. C.; Wardle, D.; Dorrepaal, E.

    2014-12-01

    Open-top chambers (OTCs) are widely used to passively increase soil and air temperature in various open habitats, such as alpine and arctic tundra, and temperate grasslands. Several studies report warming effects of 1-2 °C in arctic and alpine tundra, and up to 6 °C in temperate grasslands. The variation between studies can be mostly attributed to differences in the abiotic environment, such as snow cover and solar irradiance. Vegetation height and openness affects the amount of irradiance that reaches the ground and may therefore indirectly impact the effectiveness of OTCs. The use of OTCs in forested ecosystems might therefore be limited by reduced canopy openness, while their effect on changes in soil temperature and soil moisture content might additionally be affected by the understory vegetation type and cover. Nevertheless, OTC's are an immensely useful tool in climate-change studies, and could benefit research in forest ecosystems. In this study we therefore investigated whether OTCs can be used to manipulate microclimate in the northern boreal forest and how tree canopy cover and understory vegetation influence OTC effects on air and soil temperature and on soil moisture content.We compared OTC effects at ten sites that were situated along a fire chronosequence in the northern boreal forest in Sweden. Sites were dominated by Pinus sylvestris and Picea abies, and time since the last fire ranged from 47-367 years, resulting in varying degrees of tree canopy openness. We applied full factorial combinations of OTC warming and dwarf shrub removal and moss removal at each site. We measured canopy cover using hemispherical photography; air and soil temperature as well as soil moisture were measured hourly from June until September. Preliminary analyses indicate that OTCs increased monthly mean air temperatures by up to 0.9 °C across all treatments and forest stands. However, the degree of warming showed clear relations with the presence or absence of the

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  7. Method for automatic determination of soybean actual evapotranspiration under open top chambers (OTC) subjected to effects of water stress and air ozone concentration.

    PubMed

    Rana, Gianfranco; Katerji, Nader; Mastrorilli, Marcello

    2012-10-01

    The present study describes an operational method, based on the Katerji et al. (Eur J Agron 33:218-230, 2010) model, for determining the daily evapotranspiration (ET) for soybean inside open top chambers (OTCs). It includes two functions, calculated day par day, making it possible to separately take into account the effects of concentrations of air ozone and plant water stress. This last function was calibrated in function of the daily values of actual water reserve in the soil. The input variables of the method are (a) the diurnal values of global radiation and temperature, usually measured routinely in a standard weather station; (b) the daily values of the AOT40 index accumulated (accumulated ozone over a threshold of 40 ppb during daylight hours, when global radiation exceeds 50 Wm(-2)) determined inside the OTC; and (c) the actual water reserve in the soil, at the beginning of the trial. The ensemble of these input variables can be automatable; thus, the proposed method could be applied in routine. The ability of the method to take into account contrasting conditions of ozone air concentration and water stress was evaluated over three successive years, for 513 days, in ten crop growth cycles, excluding the days employed to calibrate the method. Tests were carried out in several chambers for each year and take into account the intra- and inter-year variability of ET measured inside the OTCs. On the daily scale, the slope of the linear regression between the ET measured by the soil water balance and that calculated by the proposed method, under different water conditions, are 0.98 and 1.05 for the filtered and unfiltered (or enriched) OTCs with root mean square error (RMSE) equal to 0.77 and 1.07 mm, respectively. On the seasonal scale, the mean difference between measured and calculated ET is equal to +5% and +11% for the filtered and unfiltered OTCs, respectively. The ability of the proposed method to estimate the daily and seasonal ET inside the OTCs is

  8. CO[sub 2] exchange and growth of the Crassulacean acid metabolism plant opuntia ficus-indica under elevated CO[sub 2] in open-top chambers

    SciTech Connect

    Cui, M.; Miller, P.M.; Nobel, P.S. )

    1993-10-01

    CO[sub 2] uptake, water vapor conductance, and biomass production of Opuntia ficus-indica, a Crassulacean acid metabolism species, were studied at CO[sub 2] concentrations of 370, 520, and 720 [mu]L L[sup [minus]1] in open-top chambers during a 23-week period. Nine weeks after planting, daily net CO[sub 2] uptake for basal cladodes at 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2] was 76 and 98% higher, respectively, than at 370 [mu]L L[sup [minus]1]. Eight weeks after daughter cladodes emerged, their daily net CO[sub 2] uptake was 35 and 49% higher at 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2], respectively, than at 370 L L[sup [minus]1]. Daily water-use efficiency was 88% higher under elevated CO[sub 2] for basal cladodes and 57% higher for daughter cladodes. The daily net CO[sub 2] uptake capacity for basal cladodes increased for 4 weeks after planting and then remained fairly constant, whereas for daughter cladodes, it increased with cladode age, became maximal at 8 to 14 weeks, and then declined. The percentage enhancement in daily net CO[sub 2] uptake caused by elevated CO[sub 2] was greatest initially for basal cladodes and at 8 to 14 weeks for daughter cladodes. The chlorophyll content per unit fresh weight of chlorenchyma for daughter cladodes at 8 weeks was 19 and 62% lower in 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2], respectively, compared with 370 [mu]L L[sup [minus]1]. Despite the reduced chlorophyll content, plant biomass production during 23 weeks in 520 and 720 [mu]L L[sup [minus]1] of CO[sub 2] was 21 and 55% higher, respectively, than at 370 [mu]L L[sup [minus]1]. The root dry weight nearly tripled as the CO[sub 2] concentration was doubled, causing the root/shoot ratio to increase with CO[sub 2] concentration. During the 23-week period, elevated CO[sub 2] significantly increased CO[sub 2] uptake and biomass production of O. 35 refs., 4 figs., 1 tab.

  9. CO2 Exchange and Growth of the Crassulacean Acid Metabolism Plant Opuntia ficus-indica under Elevated CO2 in Open-Top Chambers.

    PubMed Central

    Cui, M.; Miller, P. M.; Nobel, P. S.

    1993-01-01

    CO2 uptake, water vapor conductance, and biomass production of Opuntia ficus-indica, a Crassulacean acid metabolism species, were studied at CO2 concentrations of 370, 520, and 720 [mu]L L-1 in open-top chambers during a 23-week period. Nine weeks after planting, daily net CO2 uptake for basal cladodes at 520 and 720 [mu]L L-1 of CO2 was 76 and 98% higher, respectively, than at 370 [mu]L L-1. Eight weeks after daughter cladodes emerged, their daily net CO2 uptake was 35 and 49% higher at 520 and 720 [mu]L L-1 of C02, respectively, than at 370 [mu]L L-1. Daily water-use efficiency was 88% higher under elevated CO2 for basal cladodes and 57% higher for daughter cladodes. The daily net CO2 uptake capacity for basal cladodes increased for 4 weeks after planting and then remained fairly constant, whereas for daughter cladodes, it increased with cladode age, became maximal at 8 to 14 weeks, and then declined. The percentage enhancement in daily net CO2 uptake caused by elevated CO2 was greatest initially for basal cladodes and at 8 to 14 weeks for daughter cladodes. The chlorophyll content per unit fresh weight of chlorenchyma for daughter cladodes at 8 weeks was 19 and 62% lower in 520 and 720 [mu]L L-1 of CO2, respectively, compared with 370 [mu]L L-1. Despite the reduced chlorophyll content, plant biomass production during 23 weeks in 520 and 720 [mu]L L-1 of CO2 was 21 and 55% higher, respectively, than at 370 [mu]L L-1. The root dry weight nearly tripled as the C02 concentration was doubled, causing the root/shoot ratio to increase with CO2 concentration. During the 23-week period, elevated CO2 significantly increased CO2 uptake and biomass production of O. ficus-indica. PMID:12231958

  10. CO2 Exchange and Growth of the Crassulacean Acid Metabolism Plant Opuntia ficus-indica under Elevated CO2 in Open-Top Chambers.

    PubMed

    Cui, M.; Miller, P. M.; Nobel, P. S.

    1993-10-01

    CO2 uptake, water vapor conductance, and biomass production of Opuntia ficus-indica, a Crassulacean acid metabolism species, were studied at CO2 concentrations of 370, 520, and 720 [mu]L L-1 in open-top chambers during a 23-week period. Nine weeks after planting, daily net CO2 uptake for basal cladodes at 520 and 720 [mu]L L-1 of CO2 was 76 and 98% higher, respectively, than at 370 [mu]L L-1. Eight weeks after daughter cladodes emerged, their daily net CO2 uptake was 35 and 49% higher at 520 and 720 [mu]L L-1 of C02, respectively, than at 370 [mu]L L-1. Daily water-use efficiency was 88% higher under elevated CO2 for basal cladodes and 57% higher for daughter cladodes. The daily net CO2 uptake capacity for basal cladodes increased for 4 weeks after planting and then remained fairly constant, whereas for daughter cladodes, it increased with cladode age, became maximal at 8 to 14 weeks, and then declined. The percentage enhancement in daily net CO2 uptake caused by elevated CO2 was greatest initially for basal cladodes and at 8 to 14 weeks for daughter cladodes. The chlorophyll content per unit fresh weight of chlorenchyma for daughter cladodes at 8 weeks was 19 and 62% lower in 520 and 720 [mu]L L-1 of CO2, respectively, compared with 370 [mu]L L-1. Despite the reduced chlorophyll content, plant biomass production during 23 weeks in 520 and 720 [mu]L L-1 of CO2 was 21 and 55% higher, respectively, than at 370 [mu]L L-1. The root dry weight nearly tripled as the C02 concentration was doubled, causing the root/shoot ratio to increase with CO2 concentration. During the 23-week period, elevated CO2 significantly increased CO2 uptake and biomass production of O. ficus-indica.

  11. A flux-based assessment of the effects of ozone on foliar injury, photosynthesis, and yield of bean (Phaseolus vulgaris L. cv. Borlotto Nano Lingua di Fuoco) in open-top chambers.

    PubMed

    Gerosa, Giacomo; Marzuoli, Riccardo; Rossini, Micol; Panigada, Cinzia; Meroni, Michele; Colombo, Roberto; Faoro, Franco; Iriti, Marcello

    2009-05-01

    Stomatal ozone uptake, determined with the Jarvis' approach, was related to photosynthetic efficiency assessed by chlorophyll fluorescence and reflectance measurements in open-top chamber experiments on Phaseolus vulgaris. The effects of O(3) exposure were also evaluated in terms of visible and microscopical leaf injury and plant productivity. Results showed that microscopical leaf symptoms, assessed as cell death and H(2)O(2) accumulation, preceded by 3-4 days the appearance of visible symptoms. An effective dose of ozone stomatal flux for visible leaf damages was found around 1.33 mmol O(3) m(-2). Significant linear dose-response relationships were obtained between accumulated fluxes and optical indices (PRI, NDI, DeltaF/F'(m)). The negative effects on photosynthesis reduced plant productivity, affecting the number of pods and seeds, but not seed weight. These results, besides contributing to the development of a flux-based ozone risk assessment for crops in Europe, highlight the potentiality of reflectance measurements for the early detection of ozone stress.

  12. Effect of canopy structure and open-top chamber techniques on micrometeorological parameters and the gradients and transport of water vapor, carbon dioxide and ozone in the canopies of plum trees (`prunus salicina`) in the San Joaquin valley. Final report

    SciTech Connect

    Grantz, D.A.; Vaughn, D.L.; Metheny, P.A.; Malkus, P.; Wosnik, K.

    1995-03-15

    Plum trees (Prunus salicina cv. Casselman) were exposed to ozone in open-top chambers (OTC) or chamberless plots, and trace gas concentrations and microenvironmental conditions were monitored within tree canopies inside the outside the OTC. Concentrations of ozone, carbon dioxide and water vapor, leaf and air temperature, light intensity, and wind speed were measured at nine positions in the tree canopies. The objectives were to: (1) map the distribution of microenvironmental parameters within the canopies inside and outside the OTC; (2) determine transport parameters for gas exchange, and (3) calculate ozone flux. Significant vertical and horizontal gradients were observed; gradients were diminished and often inverted inside relative to outside the OTC due to air distribution at the bottom of the OCT. Ozone flux was readily modeled from measures of stomatal conductance, nonstomatal conductance and ozone concentration at the leaf surface.

  13. Evaluation of physiological and biochemical responses of two rice (Oryza sativa L.) cultivars to ambient air pollution using open top chambers at a rural site in India.

    PubMed

    Rai, Richa; Agrawal, Madhoolika

    2008-12-15

    Air pollutant concentrations are rising in India, causing potential threats to crop production. As air pollutants are known to interfere with physiological processes, this study was conducted to assess the relative responses of physiological and biochemical characteristics of two cultivars of rice (Oryza sativa L. cv. Saurabh 950 and NDR 97) leading to variable yield responses. Twelve hour monitoring of ambient concentrations of SO2, NO2 and O3 in filtered chambers (FCs), non-filtered chambers (NFCs) and open plots (OPs) showed that O3 was the main pollutant at the experimental site. Ozone concentrations often exceeded 40 ppb during anthesis but not during the vegetative growth period. Photosynthetic rate (Ps), stomatal conductance (g(s)) and Fv/Fm ratio, superoxide dismutase (SOD) and peroxidase (POD) activities and photosynthetic pigments, ascorbic acid, total phenolics and protein contents were assessed at different developmental stages and yield of grains were quantified. Lipid peroxidation, SOD and POD activities, ascorbic acid and total phenolics were higher, whereas Ps, g(s), Fv/Fm ratio and contents of protein and photosynthetic pigment were lower in plants of NFCs as compared to FCs. Yield decreased significantly in both cultivars grown in NFCs. NDR 97 showed less reductions in physiological characteristics, photosynthetic pigments and protein, but a greater increase in the antioxidative defense system as compared to Saurabh 950. Yield reduction was higher in NDR 97 than in Saurabh 950. This suggested that NDR 97 utilized more photosynthate in maintaining the metabolic machinery against O3 stress leading to lower translocation of photosynthate to reproductive parts. The study concluded that under natural field conditions, physiological and biochemical responses of plants varied with pollutant concentrations leading to different translocation strategies in plants, modifying their yield responses. NDR 97, a fast growing and high yielding cultivar was more

  14. Influences of elevated CO[sub 2] on CO[sub 2] uptake and biomass production for the CAM plant Opuntia ficus-indica in open-top chambers

    SciTech Connect

    Cui, M.; Miller, P.M.; Nobel, P.S. )

    1993-06-01

    CO[sub 2] uptake, water vapor conductance, and biomass production of the CAM plant Opuntia ficus-indica were studied at the current and two elevated CO[sub 2] concentrations (plus 150 and plus 350 [mu]L L[sup [minus]1]) in open-top chambers over a 23-week period. Nine weeks after planting, daily net CO[sub 2] uptake for basal cladodes in the medium and the high CO[sub 2] treatments was 49% and 84% higher, respectively, than at the current CO[sub 2] concentration. Nine weeks after the first-daughter cladodes emerged, their daily net CO[sub 2] uptake was 35% and 49% higher, respectively, in the medium and the high CO[sub 2] treatments than at the current CO[sub 2] concentration. Despite significantly lower chlorophyll contents (19% and 62%, respectively) in the first-daughter cladodes, biomass production over 23 weeks in the medium and the high CO[sub 2] treatments was 22% and 50% higher, respectively, than for plants at the current CO[sub 2].

  15. Evaluation of changes in lipid peroxidation, ROS production, surface structures, secondary metabolites and yield of linseed (Linum usitatissimum L.) under individual and combined stress of ultraviolet-B and ozone using open top chambers.

    PubMed

    Tripathi, Ruchika; Agrawal, S B

    2013-08-01

    The individual and interactive effects of supplemental UV-B (sUV-B) (ambient + 7.2 kJ m(-2) d(-1)) and elevated O3 (ambient + 10 ppb) were evaluated under field conditions using open top chambers on two cultivars, Padmini and T-397 of linseed (Linum usitatissimum L.). Mean monthly surface level of O3 concentrations varied from 27.7 ppb to 59.0 ppb during the experimental period. Both UV-B and O03 induced the production of ROS (H2O2 and O2*-), resulting in significant damage of membranes due to lipid peroxidation and electrolyte leakage. Synthesis of secondary metabolites (flavonoids, anthocyanin, lignin and wax) was also enhanced in all the treatments, whereas biomass and yield were reduced. Alterations in frequency of stomata and wax distribution were also observed through scanning electron microscopy (SEM). Cultivar Padmini was found to be more sensitive because of higher damage of membrane vis-a-vis reduction in biomass and seed yield. However, concentrations of flavonoids, anthocyanin, lignin and wax were higher in T-397, suggesting its relative resistance against applied stress. Combined exposure of sUV-B and O3 was less harmful, as compared to their individual treatment. Among the three treatments, O3 was found to be more detrimental for overall growth and sUV-B for economic yield.

  16. Self-organization of hydrothermal outflow and recharge in young oceanic crust: Constraints from open-top porous convection analog experiments

    NASA Astrophysics Data System (ADS)

    Mittelstaedt, E. L.; Olive, J. A. L.; Barreyre, T.

    2016-12-01

    Hydrothermal circulation at the axis of mid-ocean ridges has a profound effect on chemical and biological processes in the deep ocean, and influences the thermo-mechanical state of young oceanic lithosphere. Yet, the geometry of fluid pathways beneath the seafloor and its relation to spatial gradients in crustal permeability remain enigmatic. Here we present new laboratory models of hydrothermal circulation aimed at constraining the self-organization of porous convection cells in homogeneous as well as highly heterogeneous crust analogs. Oceanic crust analogs of known permeability are constructed using uniform glass spheres and 3-D printed plastics with a network of mutually perpendicular tubes. These materials are saturated with corn syrup-water mixtures and heated at their base by a resistive silicone strip heater to initiate thermal convection. A layer of pure fluid (i.e., an analog ocean) overlies the porous medium and allows an "open-top" boundary condition. Areas of fluid discharge from the crust into the ocean are identified by illuminating microscopic glass particles carried by the fluid, using laser sheets. Using particle image velocimetry, we estimate fluid discharge rates as well as the location and extent of fluid recharge. Thermo-couples distributed throughout the crust provide insights into the geometry of convection cells at depth, and enable estimates of convective heat flux, which can be compared to the heat supplied at the base of the system. Preliminary results indicate that in homogeneous crust, convection is largely confined to the narrow slot overlying the heat source. Regularly spaced discharge zones appear focused while recharge areas appear diffuse, and qualitatively resemble the along-axis distribution of hydrothermal fields at oceanic spreading centers. By varying the permeability of the crustal analogs, the viscosity of the convecting fluid, and the imposed basal temperature, our experiments span Rayleigh numbers between 10 and 10

  17. Designing an oscillating CO2 concentration experiment for field chambers

    USDA-ARS?s Scientific Manuscript database

    Questions have arisen about photosynthetic response to fluctuating carbon dioxide (CO2), which might affect yield in free-air CO2 enrichment (FACE) systems and in open top chambers. A few studies have been conducted based on CO2 controlled to cycles of fixed time-periods and fixed, large amplitude....

  18. Designing an oscillating CO2 concentration experiment for fild chambers

    USDA-ARS?s Scientific Manuscript database

    Questions have arisen about photosynthetic response to fluctuating carbon dioxide (CO2), which might affect yield in free-air CO2 enrichment (FACE) systems and in open top chambers. A few studies have been conducted based on CO2 controlled to cycles of fixed time-periods and fixed, large amplitude....

  19. A COMBINED USE OF EDDY-COVARIANCE AND OPEN-TOP CHAMBERS FOR THE IDENTIFICATION OF DOSE-EFFECT RELATIONSHIPS FOR OZONE ON CROPS. A CASE STUDY AND PERSPECTIVES

    NASA Astrophysics Data System (ADS)

    Gerosa, G.; Finco, A.; Marzuoli, R.; Migliorati, L.; Cieslik, S.; Ballarin-Denti, A.

    2009-12-01

    In the latter years a flux-based approach for ozone risk assessment on crops was strongly supported by the scientific community. Nevertheless, the amount of ozone absorbed by plants through stomata is hardly measurable and very few dose-response relationships are available in the literature. Field experiments are usually performed in OTC (or Free Air Ozone Enrichment Systems, where available) and ozone dose is calculated (not measured) by stomatal conductance models fed with climatic parameters measured in the OTCs. At the moment OTCs are the only affordable system able to remove ozone molecules in field conditions and able to provide a “control” treatment for the validation of the ozone effects. At the same time the only way to measure ozone fluxes on vegetation is the Eddy Covariance (EC), a micrometeorological technique that, unfortunately, cannot be applied inside OTCs. These two techniques were combined and simultaneously used to study the effects of the ozone uptake by alfalfa fields in a two years pilot experiment in Italy. An EC tower mounted in the middle of the field and three OTC were placed randomly on a side of the field, two of them flushed with charcoal-filtered air (ozone-free) and one with ambient air only. The plant productivity within the OTCs and in the open field, as well as the forage quality, were compared at the end of each growing cycle. With the total ozone fluxes and water and heat ones obtained from the EC measurements, a resistive analysis was conducted in order to get the stomatal resistance of plants in the open field and thus their ozone uptake. Then, the ozone uptake by the plants inside the OTCs was calculated by assuming the same stomatal resistance obtained in the open field but applying an atmospheric Ra and sub-laminar Rb resistances fit on the OTC geometry and fan system flow. The results show that a considerably amount of the ozone deposited on the field was absorbed by plants through the stomata, with values between 66

  20. Emulsion Chamber Technology Experiment (ECT)

    NASA Technical Reports Server (NTRS)

    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.

  1. Insights on carbon budgets for Ponderosa pine systems growing at three levels of CO[sub 2] and of nitrogen from leaf to whole open-top chamber flux measurements

    SciTech Connect

    Ball, J.T.; Picone, J.B.; Ross, P.D.; Ross, G.N.; Johnson, D.W. )

    1994-06-01

    At any scale of integration carbon accumulation in the biosphere is a small difference between large input and output terms and is proportional to resource levels. This can result in the impression that growth and carbon accumulation have little to do with either the input or output rates. Our measurements show that rising concentration of CO[sub 2] in the atmosphere results in biospheric influx and efflux of carbon increasing and the proportionality between carbon left and nitrogen in the system changing. A gap exists between the carbon balance inferred from gas-exchange and measured changes in pool sizes. The rhizosphere is the likely harbor for much of this [open quotes]missing carbon[close quotes]. These measurements were made on ponderosa pine saplings growing near Placerville, California USA. The chambers are set at ambient, 525 ppm, 700 ppm CO[sub 2]. Soil nitrogen levels are at the background level, plus 10 g/m[sup [minus]2] or plus 20 g/m[sup [minus]2].

  2. Experience with the jet chamber of the JADE-experiment

    SciTech Connect

    Heuer, R.D.

    1984-01-01

    The jet chamber, a pictorial drift chamber used as the central track detector of the JADE experiment at PETRA, is briefly described. The present status of the spatial and dE/dx resolutions and the experience during 4 years of operation is reported. Improvement plans for the readout electronics are described and a short review of the jet chamber designed for the proposed LEP experiment OPAL is given.

  3. The emulsion chamber technology experiment

    NASA Technical Reports Server (NTRS)

    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.

  4. Dynamic consideration of smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Chuang, Wayne K.; Donahue, Neil M.

    2017-08-01

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

  5. Drift chambers in BM@N Experiment

    NASA Astrophysics Data System (ADS)

    Fedorišin, Ján

    2017-03-01

    Drift chambers (DCH) constitute an important part of the tracking system of BM@N experiment designed to study the production of baryonic matter at the Nuclotron energies. The method of particle hit and track reconstruction in the drift chambers is proposed and tested on the BM@N deuteron beam data. In first step, the radius vs drift time calibration curve is estimated and applied to calculate DCH hit closest approach coordinates. These coordinates are used to construct hits in each DCH under the assumption of track linearity. Hits in both the DCHs are subsequently aligned and fitted to produce global linear track candidates. Eventually the hit and track reconstruction is optimized by the autocalibration method. The coordinate resolutions are estimated from Gaussian fits of the DCH hit residual spectra for different DCH planes. Furthermore, the deuteron beam momentum value is reconstructed in order to check reliability of the employed track reconstruction algorithm.

  6. Bubble chambers for experiments in nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    DiGiovine, B.; Henderson, D.; Holt, R. J.; Raut, R.; Rehm, K. E.; Robinson, A.; Sonnenschein, A.; Rusev, G.; Tonchev, A. P.; Ugalde, C.

    2015-05-01

    A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with γ-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross-sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning temperatures are dominated by radiative captures, in this experimental scheme we measure the time-reversed processes. Such photodisintegrations allow us to compute the radiative capture cross-sections when transitions to excited states of the reaction products are negligible. Due to the transformation of phase space, the photodisintegration cross-sections are up to two orders of magnitude higher. The main advantage of the new target-detector system is a density several orders of magnitude higher than conventional gas targets. Also, the detector is virtually insensitive to the γ-ray beam itself, thus allowing us to detect only the products of the nuclear reaction of interest. The development and the operation as well as the advantages and disadvantages of the bubble chamber are discussed.

  7. A new cylindrical drift chamber for the MEG II experiment

    NASA Astrophysics Data System (ADS)

    Baldini, A. M.; Baracchini, E.; Berretta, L.; Bianucci, S.; Cavoto, G.; Chiarello, G.; Chiri, C.; Cei, F.; Corvaglia, A.; Dussoni, S.; Fahrni, D.; Galli, L.; Grancagnolo, F.; Grassi, M.; Hofer, A.; Hildebrandt, M.; Ignatov, F.; Miccoli, A.; Nicolò, D.; Orsini, A.; Panareo, M.; Pepino, A.; Pinto, C.; Piredda, G.; Signorelli, G.; Raffaelli, F.; Recchia, L.; Renga, F.; Ripiccini, E.; Tassielli, G.; Tazzioli, A.; Tenchini, F.; Venturini, M.; Voena, C.; Zullo, A.

    2016-07-01

    A new cylindrical drift chamber is currently under construction for the MEG II experiment. The chamber is meant to track low momentum positrons from μ+ decays to search for μ+ →e+ γ events. The detector is segmented in very small drift cells, placed in stereo configuration and operated in a helium-isobutane gas mixture. The use of thin aluminium wires and light gas mixture set the total radiation length of the chamber to only 1.6 ×10-3X0 per track turn allowing for a momentum resolution of 120 keV/c.

  8. Large area emulsion chamber experiments for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Parnell, T. A.

    1985-01-01

    Emulsion-chamber experiments employing nuclear-track emulsions, etchable plastic detectors, metal plates, and X-ray films continue to demonstrate high productivity and potential in the study of cosmic-ray primaries and their interactions. Emulsions, with unsurpassed track-recording capability, provide an appropriate medium for the study of nucleus-nucleus interactions at high energy, which will likely produce observations of a phase change in nuclear matter. The many advantages of emulsion chambers (excellent multitrack recording capability, large geometry factor, low apparatus cost, simplicity of design and construction) are complemented by the major advantages of the Space Shuttle as an experiment carrier. A Shuttle experiment which could make a significant advance in both cosmic-ray primary and nucleus-nucleus interaction studies is described. Such an experiment would serve as a guide for use of emulsions during the Space Station era. Some practical factors that must be considered in planning a Shuttle exposure of emulsion chambers are discussed.

  9. Japan - USSR joint emulsion chamber experiment at Pamir

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The results are presented for the systematic measurement of cosmic ray showers in the first carbon chamber of Japan-USSR joint experiment at Pamir Plateau. The intensity and the energy distribution of electromagnetic particles, of hadrons and of families are in good agreement with the results of other mountain experiment if the relative error in energy estimation is taken into consideration.

  10. CHAMBER - IONIZATION - EXPERIMENT - GEMINI-TITAN (GT)-6 EQUIPMENT - CAPE

    NASA Image and Video Library

    1965-12-10

    S65-61788 (For release: 11 Dec. 1965) --- Close-up view of equipment which will be used in the D-8 (Radiation in Spacecraft) experiment on the National Aeronautics and Space Administration's Gemini-6 spaceflight. This experiment is designed to make highly accurate measurements of the absorbed dose rate of radiation which penetrates the Gemini spacecraft, and determine the spatial distribution of dose levels inside the spacecraft particularly in the crew area. This is experimentation of the U.S. Air Force Weapons Laboratory, Kirtland AFB, N.M. LOWER LEFT: The second ionization chamber, this one is unshielded. This chamber can be removed from its bracket by the astronaut who will periodically take measurements at various locations in the spacecraft. Nearby is Passive Dosimeter Unit which is one of five small packets each containing a standard pocket ionization chamber, gamma electron sensitive film, glass needles and thermo luminescent dosimeters which are mounted at various locations in the cabin. UPPER LEFT: Photo illustrates how ionization chamber can be removed from bracket for measurements. LOWER RIGHT: Shield of bulb-shaped chamber will be removed (shown in photo) as the spacecraft passes through the South Atlantic anomaly, the area where the radiation belt dips closest to Earth's surface. UPPER RIGHT: Dome-shaped object is shield covering one of two Tissue Equivalent Ionization Chambers (sensors) which will read out continuously the instantaneous rate at which dose is delivered during the flight. This chamber is mounted permanently. The information will be recorded aboard the spacecraft, and will also be received directly by ground stations. This chamber is shielded to simulate the amount of radiation the crew members are receiving beneath their skin. Photo credit: NASA or National Aeronautics and Space Administration

  11. Plasma Crystal-3 Plus experiment Chamber Leak Check

    NASA Image and Video Library

    2010-07-01

    ISS024-E-007144 (1 July 2010) --- Russian cosmonaut Alexander Skvortsov, Expedition 24 commander, performs chamber leak checks on the new Plasma Crystal-3 Plus experiment in the Poisk Mini-Research Module 2 (MRM2) of the International Space Station.

  12. Dedicated contamination experiments in the Orion laser target chamber

    NASA Astrophysics Data System (ADS)

    Andrew, J.; Chevalier, J.-M.; Egan, D.; Geille, A.; Jadaud, J.-P.; Quessada, J.-H.; Raffestin, D.; Rubery, M.; Treadwell, P.; Videau, L.

    2015-11-01

    The use of solid targets irradiated in a vacuum target chamber by focussed high energy, high power laser beams to study the properties of matter at high densities, pressures and temperatures are well known. An undesirable side effect of these interactions is the generation of plumes of solid, liquid and gaseous matter which move away from the target and coat or physically damage surfaces within the target chamber. The largest aperture surfaces in these chambers are usually the large, high specification optical components used to produce the extreme conditions being studied [e.g. large aperture off axis parabolas, aspheric lenses, X ray optics and planar debris shields]. In order to study these plumes and the effects that they produce a set of dedicated experiments were performed to evaluate target by product coating distributions and particle velocities by a combined diagnostic instrument that utilised metal witness plates, polymer witness plates, fibre velocimetry and low density foam particle catchers.

  13. Outdoor smog-chamber experiments: reactivity of methanol exhaust

    SciTech Connect

    Jeffries, H.E.; Sexton, K.G.; Holleman, M.S.

    1985-09-01

    The purpose of the report was to provide an experimental smog-chamber database especially designed to test photochemical kinetics mechanisms that would be used to assess the effects of methanol fuel use in automobiles. The mechanisms would be used in urban air-quality control models to investigate the advantages of large-scale use of methanol fuel in automobiles. The smog-chamber experiments were performed during three summer months. They have been added to the existing UNC database for photochemical mechanism validation and testing, bringing the total number of dual experiments in the database to over 400. Three different hydrocarbon mixtures were used: a 13-component mixture representing synthetic automobile exhaust; an 18-component mixture representing synthetic urban ambient hydrocarbons; and a 14-component mixture derived from the synthetic automobile exhaust by the addition of n-butane. Three different synthetic methanol-exhaust mixtures were used: 80% methanol/10% formaldehyde; and 100% methanol.

  14. Overview of the n3He Experiment and Target Chamber

    NASA Astrophysics Data System (ADS)

    McCrea, Mark; n3He Collaboration

    2017-01-01

    The n3He Experiment aims to measure the parity-violating asymmetry in the direction of proton emission relative to the initial neutron polarization direction in the reaction n-> +3 He -> T + p + 765 keV to a high precision. The size of the asymmetry is estimated to be in the range - 9 . 5 - 2 . 5 ×10-8 , and our goal statistical accuracy is 2 ×10-8 . The experiment ran at the Spallation Neutron Source with data taking completing at the end of 2015. The experiment used a Helium-3 ionization chamber as the combined target and detector. Data analysis is underway and is currently in an advanced stage

  15. The full stereo drift chamber for the MEG II experiment

    NASA Astrophysics Data System (ADS)

    Chiarello, G.

    2017-03-01

    The MEG experiment, at the Paul Scherrer Institute (PSI) near Zurich in Switzerland, aims at searching for the charged-lepton-flavor-violating decay μ+arrow e+γ, prohibited in the Standard Model but allowed, at a measurable level, in many of its extensions. MEG has already determined the world best upper limit on the branching ratio: BR(μ+arrow e+γ)<4.2×10‑13 at 90% CL with the full data set collected in the years 2009–2013. A further improvement of the MEG single event sensitivity requires a substantial upgrade of the detector performances and, in particular, the complete replacement of the positron tracker. The MEG upgrade experiment (MEG II) is currently under construction and it is conceived in order to further improve the sensitivity by one order of magnitude in three years of data taking. The new positron tracker is a high transparency single volume, full stereo cylindrical Drift Chamber, immersed in a non uniform longitudinal B-field, co-axial to the muon beam line. Due to the high wire density (12 wires/cm2), the use of the traditional feed-through technique as wire anchoring system could hardly be implemented and therefore it was necessary to develop new wiring strategies. The number of wires and the stringent requirements on the precision of their position and on the uniformity of the wire mechanical tension impose the use of an automatic system to operate the wiring procedures. The drift chamber is currently under construction at INFN Lecce and Pisa, and should be completed by the summer 2017 to be then delivered to PSI for commissioning. The upgraded detector, the new drift chamber and its construction technique, will be described.

  16. The INAF/IAPS Plasma Chamber for ionospheric simulation experiment

    NASA Astrophysics Data System (ADS)

    Diego, Piero

    2016-04-01

    The plasma chamber is particularly suitable to perform studies for the following applications: - plasma compatibility and functional tests on payloads envisioned to operate in the ionosphere (e.g. sensors onboard satellites, exposed to the external plasma environment); - calibration/testing of plasma diagnostic sensors; - characterization and compatibility tests on components for space applications (e.g. optical elements, harness, satellite paints, photo-voltaic cells, etc.); - experiments on satellite charging in a space plasma environment; - tests on active experiments which use ion, electron or plasma sources (ion thrusters, hollow cathodes, field effect emitters, plasma contactors, etc.); - possible studies relevant to fundamental space plasma physics. The facility consists of a large volume vacuum tank (a cylinder of length 4.5 m and diameter 1.7 m) equipped with a Kaufman type plasma source, operating with Argon gas, capable to generate a plasma beam with parameters (i.e. density and electron temperature) close to the values encountered in the ionosphere at F layer altitudes. The plasma beam (A+ ions and electrons) is accelerated into the chamber at a velocity that reproduces the relative motion between an orbiting satellite and the ionosphere (≈ 8 km/s). This feature, in particular, allows laboratory simulations of the actual compression and depletion phenomena which take place in the ram and wake regions around satellites moving through the ionosphere. The reproduced plasma environment is monitored using Langmuir Probes (LP) and Retarding Potential Analyzers (RPA). These sensors can be automatically moved within the experimental space using a sled mechanism. Such a feature allows the acquisition of the plasma parameters all around the space payload installed into the chamber for testing. The facility is currently in use to test the payloads of CSES satellite (Chinese Seismic Electromagnetic Satellite) devoted to plasma parameters and electric field

  17. [Characterization of photochemical smog chamber and initial experiments].

    PubMed

    Jia, Long; Xu, Yong-Fu; Shi, Yu-Zhen

    2011-02-01

    A self-made new indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosols has been introduced and characterized. The characterization experiments include the measurements of wall effects for reactive species and the determination of chamber dependent * OH radical sources by CO-NO(x) irradiation experiments. Preliminary ethene-NO(x) and benzene-NO(x) experiments were conducted as well. The results of characterization experiments show that the wall effects for O3 and NO2 in a new reactor are not obvious. Relative humidity has a great effect on the wall losses in the old reactor, especially for O3. In the old reactor, the rate constant for O3 wall losses is obtained to be 1.0 x 10(-5) s(-1) (RH = 5%) and 4.0 x10(-5) s(-1) (RH = 91%), whereas for NO2, it is 1.0 x 10(-6) s(-1) (RH = 5%) and 0.6 x 10(-6) s(-1) (RH = 75%). The value for k(NO2 --> HONO) determined by CO-NO(x) irradiation experiments is (4.2-5.2) x 10(-5) s(-1) and (2.3-2.5) x 10(-5) s(-1) at RH = 5% and RH 75% -77%, respectively. The average *OH concentration is estimated to be (2.1 +/- 0.4) x 10(6) molecules/cm3 by using a reaction rate coefficient of CO and * OH. The sensitivity of chamber dependent auxiliary reactions to the O3 formation is discussed. Results show that NO2 --> HONO has the greatest impact on the O3 formation during the initial stage, N2O5 + H2O --> 2HNO3 has a minus effect to maximum O3 concentration, and that the wall losses of both O3 and NO2 have little impact on the O3 formation. The results from the ethene-NO(x) and benzene-NO(x) experiments are in good agreement with those from the MCM simulation, which reflects that the facility for the study of the formation of secondary pollution of ozone and secondary organic aerosols is reliable. This demonstrates that our facility can be further used in the deep-going study of chemical processes in the atmosphere.

  18. Forward Drift Chambers for the GlueX experiment

    NASA Astrophysics Data System (ADS)

    Pentchev, Lubomir; GlueX Collaboration

    2014-09-01

    The GlueX experiment will search for exotic mesons produced by 9 GeV linearly polarized photon beam from the 12 GeV CEBAF machine. A hermetic solenoid-based detector system that includes tracking and calorimetry has been constructed. The Forward Drift Chamber (FDC) system consists of 24 circular planar drift chambers of 1 m diameter. Additional information from cathode strips, placed at both sides of the wire planes, is required to achieve efficient pattern recognition in the presence of high background rates in forward direction, resulting in 12,500 readout channels in total. The detection of relatively low energy photons by the electro-magnetic calorimeters imposes severe constraints on the amount of the material used in the FDC. Challenges in the production of this low-mass detector will be discussed. The FDC has been completed and recently installed in the bore of the solenoid magnet. Results from the tests of the whole detector system will be presented.

  19. Advanced photon source experience with vacuum chambers for insertion devices

    SciTech Connect

    Hartog, P.D.; Grimmer, J.; Xu, S.; Trakhtenberg, E.; Wiemerslage, G.

    1997-08-01

    During the last five years, a new approach to the design and fabrication of extruded aluminum vacuum chambers for insertion devices was developed at the Advanced Photon Source (APS). With this approach, three different versions of the vacuum chamber, with vertical apertures of 12 mm, 8 mm, and 5 mm, were manufactured and tested. Twenty chambers were installed into the APS vacuum system. All have operated with beam, and 16 have been coupled with insertion devices. Two different vacuum chambers with vertical apertures of 16 mm and 11 mm were developed for the BESSY-II storage ring and 3 of 16 mm chambers were manufactured.

  20. MRI-compatible incubation chamber for cell culture experiments.

    PubMed

    Schwenzer, Nina F; Grönewäller, Eckart F; Rodegerdts, Enno; Kehlbach, Rainer; Duda, Stephan H; Claussen, Claus D

    2006-01-01

    To develop an incubation chamber that is compatible with MRI, while avoiding sources of error due to the experimental setup. Two identical and gas-tight chambers were constructed of Plexiglas. The temperature and the CO(2) concentration were adjustable. Temperature variations within and between both chambers were measured. The pH values of the cell culture media were measured under different environmental settings. For each environment a colony formation test was carried out. The homogeneity of the magnetic field inside the chambers was estimated by phantom tests. The temperature variations within the chambers were <0.3 degrees C, and the variation between the chambers was on average <0.05 degrees C. After eight hours the pH values of the cell culture media were 7.47 and 7.48 in the reference and measurement chambers, respectively; 7.41 in the CO(2) incubator; and 8.73 in ambient air. In colony formation tests the survival fraction in the Plexiglas chamber was comparable to that in the CO(2) incubator. No distortions of the magnetic field from the incubation chamber were observed. The incubation system presented can provide the conditions of a CO(2) incubator without alteration of the magnetic flux density.

  1. Convective melting in a magma chamber: theory and numerical experiment.

    NASA Astrophysics Data System (ADS)

    Simakin, A.

    2012-04-01

    We present results of the numerical modeling of convective melting in a magma chamber in 2D. Model was pointed on the silicic system approximated with Qz-Fsp binary undersaturated with water. Viscosity was calculated as a function of the melt composition, temperature and crystal content and comprises for the pure melt 104.5-105.5 Pas. Lower boundary was taken thermally insulated in majority of the runs. Size of FEM (bilinear elements) grid for velocity is 25x25 cm and for the integration of the density term 8x8 cm. Melting of the chamber roof proceeds with the heat supply due to the chaotic thermo-compositional convection and conductive heat loose into melted substrate. We compare our numerical data with existing semi-analytical models. Theoretical studies of the assimilation rates in the magma chambers usually use theoretical semi-analytical model by Huppert and Sparks (1988) (e.g., Snyder, 2000). We find that this model has strong points: 1) Independence of the melting rate on the sill thickness (Ra>>Rac) 2) Independence of the convective heat transfer on the roof temperature 3) Determination of the exponential thermal boundary layer ahead of the melting front and weak points: 1) Ignoring the possibility of the crystallization without melting regime for narrow sills and dykes. 2)Neglecting of two-phase character of convection. 3)Ignoring of the strong viscosity variation near the melting front. Independence of convective flux from the sill size (at Ra>>Rac) allows reducing of computational domain to the geologically small size (10-15 m). Concept of exponential thermal boundary layer is also rather important. Length scale (L0) of this layer is related to the melting rate and thermal diffusivity coefficient kT as L0=kT/um and at the melting rate 10 m/yr becomes about 2 m. Such small scale implies that convective melting is very effective (small conductive heat loss) and part of the numerical domain filled with roof rocks can be taken small. In the H&S model

  2. Construction of an anechoic chamber for aeroacoustic experiments and examination of its acoustic parameters

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    The acoustic parameters of a new anechoic chamber constructed at Perm National Research Polytechnic University (PNRPU) are presented. This chamber is designed to be used, among other things, for measuring noise from aerodynamic sources. Sound-absorbing wedges lining the walls of the chamber were studied in an interferometer with normal wave incidence. The results are compared to the characteristics of sound-absorbing wedges of existing anechoic facilities. Metrological examination of the acoustic parameters of the PNRPU anechoic chamber demonstrates that free field conditions are established in it, which will make it possible to conduct quantitative acoustic experiments.

  3. Studies of particle interactions in bubble chamber, spark chambers and counter experiments. Annual progress report

    SciTech Connect

    Holloway, L.E.; O'Halloran, T.A. Jr.; Simmons, R.O.

    1983-07-01

    During the past six years we have carried out and planned experiments which predominantly studied the production and decay of particles containing charmed quarks. A series of photoproduction and neutron production experiments started with the very early observation of the production of J/psi by neutrons and by photons at Fermilab. From subsequent experiments using these neutral beams and the basic detecting system, we have reported results on the photoproduction of the ..lambda../sub c/ charmed baryon and the D and D* charmed mesons. More recent runs are studying the high energy photoproduction of vector mesons including the psi'. The present experiment in this sequence is using neutrons to produce a large number of D mesons. Another series of experiments at Fermilab set out to study the hadronic production of charmed mesons. The Chicago Cyclotron facility was modified with a detector sensitive to various possible production mechanisms. The experiments were a success; clean signals of D mesons were observed to be produced by pions, and also the production of chi/sub c/ with the subsequent decay via a ..gamma..-ray to psi was observed. The charmonium experiments run this year have better photon resolution for measuring the decays of chi/sub c/ to psi. We are part of a collaboration which is working on the Collider Detector Facility for Fermilab. The CDF at Fermilab is a possible source of (weak) intermediate vector bosons from the collisions of protons and anti-protons. Our responsibilities in the CDF include both the construction of the muon detector and the designing, planning, and testing of the FASTBUS electronics. The second part of our weak interaction program is the Neutrino Oscillation experiment which is now under construction at Brookhaven.

  4. Experiments on heat transfer in a cryogenic engine thrust chamber

    NASA Astrophysics Data System (ADS)

    Sugathan, N.; Srinivasan, K.; Srinivasa Murthy, S.

    1993-04-01

    Tests are conducted on a cryogenic engine using liquid oxygen as oxidizer and gaseous hydrogen as fuel with water as a coolant. The coolant flow passage of the thrust chamber is of milled channel configuration. Measured heat transfer results compare well with those predicted by a thermal analysis using the standard Bartz correlation and the Hess and Kunz correlation for hot gas side and coolant side heat transfer coefficients, respectively. This confirms the conclusions of a recent theoretical study by the authors in which a comparison of various heat transfer correlations was made.

  5. Open top culverts as an alternative drainage system to minimize ecological effects in earth roads.

    NASA Astrophysics Data System (ADS)

    García, Jose L.; Elorrieta, Jose; Robredo, Jose C.; García, Ricardo; García, Fernando; Gimenez, Martin C.

    2013-04-01

    During the last fifteen years a research team from School of Forestry at the Technical University of Madrid (Spain) has developed several competitive research projects regarding forest roads and open top culverts. A first approach was established with a prototype of 7 meters length in a hydraulic channel at the laboratory determining main parameters of different open top culverts in relation to different sizes of gravels and the self washing properties relationship with different slopes up to 8 %. The curves obtained may help to properly install these drainage systems avoiding maintenance costs. In addition more targeted pilot studies were developed in different forest earth roads in center and north Spain. The construction of the stations under study was financed by the U.P.M and the R&D National Plan. The main outcomes relates the low variation of humidity in a 20 m. wide range at both sides of the open top culverts and several considerations relating the angle of installation, the spacing of such drainage systems and the benefits against rilling along the roads. Also the erosion produced downhill was established and some construction methods to avoid adverse ecological effects. The diffusion of results includes congresses and a small booklet with a great acceptance in forestry services. Also a patent (ES 2 262 437) of an advanced model has been registered.

  6. Plasma Chamber and First Wall of the Ignitor Experiment^*

    NASA Astrophysics Data System (ADS)

    Cucchiaro, A.; Coppi, B.; Bianchi, A.; Lucca, F.

    2005-10-01

    The new designs of the Plasma Chamber (PC) and of the First Wall (FW) system are based on updated scenarios for vertical plasma disruption (VDE) as well as estimates for the maximum thermal wall loadings at ignition. The PC wall thickness has been optimized to reduce the deformation during the worst disruption event without sacrificing the dimensions of the plasma column. A non linear dynamic analysis of the PC has been performed on a 360^o model of it, taking into account possible toroidal asymmetries of the halo current. Radial EM loads obtained by scaling JET measurements have been also considered. The low-cycle fatigue analysis confirms that the PC is able to meet a lifetime of few thousand cycles for the most extreme combinations of magnetic fields and plasma currents. The FW, made of Molybdenum (TZM) tiles covering the entire inner surface of the PC, has been designed to withstand thermal and EM loads, both under normal operating conditions and in case of disruption. Detailed elasto-plastic structural analyses of the most (EM) loaded tile-carriers show that these are compatible with the adopted fabrication requirements. ^*Sponsored in part by ENEA of Italy and by the U.S. DOE.

  7. Calibration of cathode strip gains in multiwire drift chambers of the GlueX experiment

    SciTech Connect

    Berdnikov, V. V.; Somov, S. V.; Pentchev, L.; Somov, A.

    2016-07-01

    A technique for calibrating cathode strip gains in multiwire drift chambers of the GlueX experiment is described. The accuracy of the technique is estimated based on Monte Carlo generated data with known gain coefficients in the strip signal channels. One of the four detector sections has been calibrated using cosmic rays. Results of drift chamber calibration on the accelerator beam upon inclusion in the GlueX experimental setup are presented.

  8. Smog chamber experiments to test oxidant related control strategy issues. Final report 1978-81

    SciTech Connect

    Kamens, R.M.; Jeffries, H.E.; Sexton, K.G.; Gerhardt, A.A.

    1982-03-01

    Outdoor smog chamber experiments were performed to address various issues relating to ozone (O3) production and oxidant control strategies. Temperature effects on single hydrocarbon-NOx systems were studied. Propylene-NOx systems were modeled with particular attention to peroxynitric acid chemistry. Mechanisms were developed to model the O3 reactions with the two major isoprene daughter products, methylvinylketone and methacrolein. Chamber systems with isoprene and O3 were also modeled.

  9. Experience With the Resistive Plate Chamber in the BaBar Experiment

    SciTech Connect

    Bellini, F.; /Rome U. /INFN, Rome

    2006-11-15

    The BABAR detector has operated nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector, for the past two years. The RPCs experience widely different background and luminosity-driven singles rates (0.01-10 Hz/cm{sup 2}) depending on position within the endcap. Some regions have integrated over 0.3 C/cm{sup 2}. RPC efficiency measured with cosmic rays and beam is high and stable. However, a few of the highest rate RPCs have suffered efficiency losses of 5-15%. Although constructed with improved techniques many of the RPCs, which are operated in streamer mode, have shown increased dark currents and noise rates that are correlated with the direction of the gas flow and the integrated current.

  10. MicroBooNE, A Liquid Argon Time Projection Chamber (LArTPC) Neutrino Experiment

    SciTech Connect

    Katori, Teppei

    2011-07-01

    Liquid Argon time projection chamber (LArTPC) is a promising detector technology for future neutrino experiments. MicroBooNE is a upcoming LArTPC neutrino experiment which will be located on-axis of Booster Neutrino Beam (BNB) at Fermilab, USA. The R&D efforts on this detection method and related neutrino interaction measurements are discussed.

  11. Open-top selective plane illumination microscope for conventionally mounted specimens

    PubMed Central

    McGorty, Ryan; Liu, Harrison; Kamiyama, Daichi; Dong, Zhiqiang; Guo, Su; Huang, Bo

    2015-01-01

    We have developed a new open-top selective plane illumination microscope (SPIM) compatible with microfluidic devices, multi-well plates, and other sample formats used in conventional inverted microscopy. Its key element is a water prism that compensates for the aberrations introduced when imaging at 45 degrees through a coverglass. We have demonstrated its unique high-content imaging capability by recording Drosophila embryo development in environmentally-controlled microfluidic channels and imaging zebrafish embryos in 96-well plates. We have also shown the imaging of C. elegans and moving Drosophila larvae on coverslips. PMID:26193587

  12. Experiment 8: Environmental Conditions in the ASTROCULTURE(trademark) Plant Chamber During the USML-2 Mission

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Zhou, Weijia; Yetka, R. A.; Draeger, N. A.

    1998-01-01

    Conducting plant research to assess the impact of microgravity on plant growth and development requires a plant chamber that has the capability to control other environmental parameters involved in plant growth and development. The environmental control in a space-based plant chamber must be equivalent to that available in such facilities used for terrestrial plant research. Additionally, plants are very sensitive to a number of atmospheric gaseous materials. Thus, the atmosphere of a plant chamber must be isolated from the space vehicle atmosphere, and the plant growth unit should have the capability to remove any such deleterious materials that may impact plant growth and development. The Wisconsin Center for Space Automation and Robotics (WCSAR), University of Wisconsin-Madison, has developed a totally enclosed controlled environment plant growth unit. The flight unit was used to support the ASTROCULTURE(TM) experiment conducted during the USML-2 mission. The experiment had two major objectives: 1) Provide further validation of the flight unit to control the experiment-defined environmental parameters in the plant chamber, and 2) support a plant experiment to assess the capability of potato plant material to produce tubers in microgravity. This paper describes the temperature, humidity, and carbon dioxide conditions of the plant chamber during the mission, from launch to landing. Another paper will present the plant response data.

  13. Experiment 8: Environmental Conditions in the ASTROCULTURE(trademark) Plant Chamber During the USML-2 Mission

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Zhou, Weijia; Yetka, R. A.; Draeger, N. A.

    1998-01-01

    Conducting plant research to assess the impact of microgravity on plant growth and development requires a plant chamber that has the capability to control other environmental parameters involved in plant growth and development. The environmental control in a space-based plant chamber must be equivalent to that available in such facilities used for terrestrial plant research. Additionally, plants are very sensitive to a number of atmospheric gaseous materials. Thus, the atmosphere of a plant chamber must be isolated from the space vehicle atmosphere, and the plant growth unit should have the capability to remove any such deleterious materials that may impact plant growth and development. The Wisconsin Center for Space Automation and Robotics (WCSAR), University of Wisconsin-Madison, has developed a totally enclosed controlled environment plant growth unit. The flight unit was used to support the ASTROCULTURE(TM) experiment conducted during the USML-2 mission. The experiment had two major objectives: 1) Provide further validation of the flight unit to control the experiment-defined environmental parameters in the plant chamber, and 2) support a plant experiment to assess the capability of potato plant material to produce tubers in microgravity. This paper describes the temperature, humidity, and carbon dioxide conditions of the plant chamber during the mission, from launch to landing. Another paper will present the plant response data.

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

    SciTech Connect

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

    2008-08-26

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

  15. Outdoor smog chamber experiments to test photochemical models. Final report May 78-May 81

    SciTech Connect

    Feffries, H.E.; Kamens, R.M.; Sexron, K.G.; Gerhardt, A.A.

    1982-04-01

    The smog chamber facility of the University of North Carolina was used in a study to provide experimental data for developing and testing kinetic mechanisms of photochemical smog formation. The smog chamber, located outdoors in rural North Carolina, is an A-frame structure covered with Teflon film. Because the chamber is partitioned into two sections, each with a volume of 156 cu m, two experiments can be conducted simultaneously. The dual chamber is operated under natural conditions of solar radiation, temperature, and relative humidity. In this study, 115 dual all-day experiments were conducted using NOx and a variety of organic species. The organic compounds investigated included various paraffins, olefins, aromatics and oxygenates, both singly and in mixtures of two or more components. In this report the data collected over the three-year period of the study are described. The experimental procedures and analytical methods used in this study and the limitations and uncertainties of the data are discussed. Guidance for modeling of the data is also given, including a detailed discussion of how to estimate photolytic rate constants from the available UV and total solar radiation data and how to treat such chamber artifacts as dilution, wall sources and losses of pollutants, and reactivity of the background air.

  16. A facility for long-term Mars simulation experiments: the Mars Environmental Simulation Chamber (MESCH).

    PubMed

    Jensen, Lars Liengaard; Merrison, Jonathan; Hansen, Aviaja Anna; Mikkelsen, Karina Aarup; Kristoffersen, Tommy; Nørnberg, Per; Lomstein, Bente Aagaard; Finster, Kai

    2008-06-01

    We describe the design, construction, and pilot operation of a Mars simulation facility comprised of a cryogenic environmental chamber, an atmospheric gas analyzer, and a xenon/mercury discharge source for UV generation. The Mars Environmental Simulation Chamber (MESCH) consists of a double-walled cylindrical chamber. The double wall provides a cooling mantle through which liquid N(2) can be circulated. A load-lock system that consists of a small pressure-exchange chamber, which can be evacuated, allows for the exchange of samples without changing the chamber environment. Fitted within the MESCH is a carousel, which holds up to 10 steel sample tubes. Rotation of the carousel is controlled by an external motor. Each sample in the carousel can be placed at any desired position. Environmental data, such as temperature, pressure, and UV exposure time, are computer logged and used in automated feedback mechanisms, enabling a wide variety of experiments that include time series. Tests of the simulation facility have successfully demonstrated its ability to produce temperature cycles and maintain low temperature (down to -140 degrees C), low atmospheric pressure (5-10 mbar), and a gas composition like that of Mars during long-term experiments.

  17. Early steps towards quarks and their interactions using neutrino beams in CERN bubble chamber experiments

    NASA Astrophysics Data System (ADS)

    Perkins, Don H.

    2016-06-01

    Results from neutrino experiments at CERN in the1970's, using bubble chamber detectors filled with heavy liquids, gave early evidence for the existence of quarks and gluons as real dynamical objects. In detail, the measured moments of the non-singlet structure functions provided crucial support for the validity of the present theory of the strong inter-quark interactions, quantum chromodynamics.

  18. Ceramic torodail vacuum chamber and wall conditioning for the ETL-TPE-2 experiment

    SciTech Connect

    Kiyama, H.; Kiyama, S.; Hakoda, K.

    1981-01-01

    TPE-2 is a torodial high /beta/screw pinch experiment with an ellitical cross section. This paper presents the design and the fabrication of the torodial ceramic vacuum chamber, the outline of the vacuum system and of major radius of 40 cm and an elliptical cross section of 28 cm.

  19. Specifications for and preliminary design of a plant growth chamber for orbital experimental experiments

    NASA Technical Reports Server (NTRS)

    Sweet, H. C.; Simmonds, R. C.

    1976-01-01

    It was proposed that plant experiments be performed on board the space shuttle. To permit the proper execution of most tests, the craft must contain a plant growth chamber which is adequately designed to control those environmental factors which can induce changes in a plant's physiology and morphology. The various needs of, and environmental factors affecting, plants are identified. The permissilbe design, construction and performance limits for a plant-growth chamber are set, and tentative designs were prepared for units which are compatible with both the botanical requirements and the constraints imposed by the space shuttle.

  20. Resistive Plate Chambers performance with Cosmic Rays in the CMS experiment

    NASA Astrophysics Data System (ADS)

    Piccolo, D.; Darmenov, N.; Genchev, V.; Iaydjiev, P.; Stoykova, S.; Sultanov, G.; Trayanov, R.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Marinov, A.; Thyssen, F.; Tytgat, M.; Verwilligen, P.; Zaganidis, N.; Akimenko, S.; Ball, A.; Crotty, I.; Guida, R.; Sharma, A.; Van Doninck, W.; Abbrescia, M.; Iaselli, G.; Marangelli, B.; Nuzzo, S.; Pugliese, G.; Romano, F.; Roselli, G.; Trentadue, R.; Tupputi, S.; Colaleo, A.; Loddo, F.; Ranieri, A.; Cimmino, A.; Sciacca, C.; Buontempo, S.; Cavallo, N.; Fabozzi, F.; Lomidtze, D.; Paolucci, P.; Benussi, L.; Bertani, M.; Bianco, S.; Colafranceschi, S.; Fabbri, F. L.; Baesso, P.; Pagano, D.; Ratti, S. P.; Vitulo, P.; Viviani, C.; Avila, C.; Carrillo, C.; Gomez, B.; Ocampo, A.; Osorio, A.; Sanabria, J. C.; Polese, G.; Tuuva, T.; Bunkowski, K.; Cwiok, M.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Kierzkowski, K.; Kudla, I. M.; Oklins, W.; Pietrusinski, M.; Bluj, M.; Fruboes, T.; Gorski, M.; Kazana, M.; Szleper, M.; Wrochna, G.; Zalewski, P.; Poznik, K. T.; Zabolotny, W.; Ban, Y.; Qian, S. J.; Ye, Y. L.; Ahmad, M.; Ahmed, I.; Ahmed, W.; Asghar, M. I.; Butt, J. B.; Hoorani, H. R.; Hussain, I.; Khan, W. A.; Khurshid, T.; Malik, I. A.; Muhammad, S.; Qazi, S. F.; Shahzad, H.; Cho, S. W.; Jo, M.; Hong, B.; Kim, C.; kim, H. C.; Kim, J. H.; Lee, H. S.; Lee, K. S.; Moon, D. H.; Park, S.; Rhee, H. B.; Seo, E. S.; Shin, S. S.; Sim, K. S.; Lee, J. S.; Lee, S. E.

    2010-05-01

    The Resistive Plate Chambers [M. Abbrescia, et al., Nucl. Instr. and Meth. A 550 (2005) 116] are used in the CMS experiment [CMS Collaboration, The CMS experiment at the CERN LHC 2008, J. Inst. 3 (2008) S08004] as a dedicated muon trigger both in barrel and endcap system. About 4000 m2 of double gap RPCs have been produced and have been installed in the experiment since more than one and half Years. The full barrel system and a fraction of the endcaps have been monitored to study dark current behaviour and system stability, and have been extensively commissioned with Cosmic Rays collected by the full CMS experiment.

  1. An exploration of patients' memories and experiences of hyperbaric oxygen therapy in a multiplace chamber.

    PubMed

    Chalmers, Andy; Mitchell, Chris; Rosenthal, Mark; Elliott, Doug

    2007-08-01

    To examine patients' memories and experiences of hyperbaric oxygen therapy in a multiplace chamber of a hyperbaric medicine unit in Australia. There is minimal literature available documenting patients' feelings and memories of hyperbaric oxygen therapy, particularly in a multiplace chamber. Exploratory. A convenience sample of seven non-emergency patients was interviewed separately at the conclusion of their multi-session therapy. A semi-structured approach elicited in-depth information regarding their experiences and memories of the hyperbaric oxygen therapy. Interviews were 30-45 minutes long and audiotaped for transcription and analysis. Field notes were also used to note non-verbal cues and other observations not evident from the audio material. Data collection ceased when data saturation was evident from the interviews. Interview transcripts were examined using a content analysis approach, with textual coding and thematic development. Issues derived from the data included: the uncertainty of the treatment; the noise and cold of the chamber; the discomfort of the mask or hood; and the boredom. Participant responses to the therapy related to previous noxious experiences and the individual's personality. This information was used to examine ways of reducing any negative feelings and experiences associated with hyperbaric oxygen therapy, thus improving the service provided to patients. Identification of these stressors and related issues may also enable subsequent development of a risk-stratification instrument to predict patients who do not complete treatment.

  2. Performance of the Time Expansion Chamber / Transition Radiation Detector in PHENIX Experiment at RHIC

    NASA Astrophysics Data System (ADS)

    Luiz Silva, Cesar

    2004-10-01

    The Time Expansion Chamber / Transition Radiation Detector (TEC/TRD) in the PHENIX Experiment at RHIC measures ionization losses (dE/dX) and transition radiation from charged particles produced by beam collisions. It is designed to perform tracking and identification for charged particles on very high particle multiplicity environment. The TEC/TRD consists of 24 wire chambers readout on both sides filled with recycled Xe-based gas mixture. This wire chamber configuration, besides providing measurements of ionization losses for charged particles, can absorb X-Ray photons generated by transition radiation from incident particles with γ>1000 crossing fiber radiators placed at the entrance of the chambers. This allows TEC/TRD to distinguish electrons from the huge pion signal produced over a broad momentum range (1GeV/c

  3. Monoplace hyperbaric chamber use of U.S. Navy Table 6: a 20-year experience.

    PubMed

    Weaver, L K

    2006-01-01

    We report a 20-year experience at LDS Hospital, Salt Lake City, UT using the U.S. Navy Treatment Table 6 (TT6) in an oxygen-filled monoplace hyperbaric chamber (1985-2004). Air breathing was provided via a demand regulator fitted with a SCUBA mouthpiece while the patient wore a nose clip. Intubated patients were mechanically ventilated with a Sechrist 500A ventilator, with a modified circuit providing air, when specified. We treated 90 patients: 72 divers (decompression sickness [DCS] = 67, arterial gas embolism [AGE] = 5), 10 hospital-associated AGE, and 8 miscellaneous conditions. They received a total of 118 TT6 (9 TT6 in intubated patients). Ninety-four percent of the TT6 schedules were tolerated and completed. The intolerance rate from two surveyed multiplace chambers was zero and 3% of 100 TT6 schedules each. Failure to complete the TT6 was due to oxygen toxicity (4) and claustrophobia (3). The U.S. Navy TT6 was well tolerated by patients with DCS or AGE treated in monoplace hyperbaric chambers, but tolerance may not be as high as when treated in the multiplace chamber.

  4. Modular deposition chamber for in situ X-ray experiments during RF and DC magnetron sputtering.

    PubMed

    Krause, Bärbel; Darma, Susan; Kaufholz, Marthe; Gräfe, Hans Hellmuth; Ulrich, Sven; Mantilla, Miguel; Weigel, Ralf; Rembold, Steffen; Baumbach, Tilo

    2012-03-01

    A new sputtering system for in situ X-ray experiments during DC and RF magnetron sputtering is described. The outstanding features of the system are the modular design of the vacuum chamber, the adjustable deposition angle, the option for plasma diagnostics, and the UHV sample transfer in order to access complementary surface analysis methods. First in situ diffraction and reflectivity measurements during RF and DC deposition of vanadium carbide demonstrate the performance of the set-up.

  5. Are magma chamber boundaries brittle or ductile? Rheological insights from thermal stressing experiments

    NASA Astrophysics Data System (ADS)

    Browning, John; Meredith, Philip G.; Gudmundsson, Agust; Lavallée, Yan; Drymoni, Kyriaki

    2015-04-01

    Rheological conditions at magma chamber boundaries remain poorly understood. Many field observations of deeply-eroded and well-exposed plutons, for example Slaufrudalur and Geitafell in SE Iceland, exhibit a sharp transition between what may have been a partially or fully molten magma chamber and its surrounding brittle host rock. Some studies have suggested a more gradual change in the rheological properties of chamber boundaries, marked by a ductile halo, which is likely to exert a significant impact on their rheological response. Understanding the state and rheological conditions of magma-rock interface and interaction is essential for constraining chamber-boundary failure conditions leading to dyke propagation, onset of volcanic eruption as well as caldera fault formation. We present results from a series of thermal stressing experiments in which we attempt to recreate the likely conditions at magma-chamber boundaries. Cores of volcanic material (25 mm diameter x 65 mm long) were heated to magmatic temperatures under controlled conditions in a horizontal tube furnace (at atmospheric pressure) and then held at those temperatures over variable dwell times. At the maximum temperatures reached, the inner part of the samples undergoes partial melting whilst the outer part remains solid. After cooling the brittle shells commonly exhibit axial, fissure-like fractures with protruded blobs of solidified melt. This phenomenon is interpreted as being the result of volume expansion during partial melting. The internal melt overpressure generates fluid-driven fractures analogous to filter-pressing textures or on a large scale, dykes. We complement our observations with acoustic emission and seismic velocity data obtained from measurements throughout the experiments. These complementary data are used to infer the style and timescale of fracture formation. Our results pinpoint the temperature ranges over which brittle fractures form as a result of internal melt overpressure

  6. Growing Male Rats in Individually Ventilated and Open-Top Cages

    PubMed Central

    Kostomitsopoulos, Nikolaos; Dontas, Ismene A; Alexakos, Pavlos; Lelovas, Pavlos; Galanos, Antonios; Paronis, Euthimios; Balafas, Evangelos; Paschidis, Konstantinos; Kostakis, Alkiviadis

    2011-01-01

    During the past few decades, the development and use of individually ventilated cages (IVC), which are now commercially available for housing laboratory mice and rats, have increased. Because limited information is available regarding the influence of caging systems on the growth of rats, the present study assessed body weight and food and water consumption in growing male rats that were housed in IVC and open-top cages (OTC). We allocated 21-d-old male Wistar outbred rats (HsdOla:WI; n = 24) into 2 groups, which then were housed in pairs in IVC (n = 12) and OTC (n = 12). After an 8-d acclimatization period, body weight and food and water consumption were assessed every 3 d until the rats were 94 d old. There were no significant differences between the body weights of rats housed in IVC compared with OTC over the 65-d observation period. Food and water consumption were greater in rats housed in OTC compared with IVC, becoming significantly different when the rats were 50 and 53 d old, respectively. In conclusion, IVC and OTC housing conditions influenced food and water intakes but not body weight in growing male rats. Further research is needed to clarify the exact basis for these changes in food and water consumption. PMID:22330780

  7. A Current Mode Ion Chamber for the n+p->D+gamma Parity Violation Experiment

    NASA Astrophysics Data System (ADS)

    Snow, William

    2001-04-01

    We have developed and tested a current-mode 3He-based ion chamber for the measurement of the neutron time-of-flight spectrum from a pulsed cold neutron source on a pulse-by-pulse basis. Such a device is required in the n+p->D+gamma experiment for general diagnostic purposes and for monitoring the ortho-para ratio in the liquid hydrogen target by neutron transmission. This detector was tested in the fall of 2000 at the LANSCE pulsed cold neutron source. The chamber operates with a mixture gas of 0.5 atm 3He and 3 atm H2 and possesses segmentation along the neutron beam. The design is similar to that of Penn et al [1] which was used for a neutron-4He parity violation experiment, but with modifications to the time response and the dynamic range in neutron energy required for operation at a pulsed neutron source. The relevant technical characteristics of the ion chamber (time response, sensitivity to Mev gammas, noise, efficiency, neutron energy dynamic range, linearity) will be described. [1] S. Penn et.al., submitted to NIM (2000)

  8. A new system of STRAW chambers operating in vacuum for the NA62 experiment

    NASA Astrophysics Data System (ADS)

    Potrebenikov, Yu

    2017-01-01

    Large 2.15 × 2.15 m2 area straw tube chambers have been developed to meet the specific requirements of the NA62 experiment. The main goal of the NA62 experiment at the CERN SPS is to measure the branching ratio of the ultra-rare decay with 10% accuracy. This can be achieved by detecting about 100 Standard Model events with 10% background in 2 - 3 years of data taking. A low mass tracking system is necessary to achieve a high resolution on kinematic quantities while timing resolution is mandatory to match the outgoing pion with the incoming kaon. Design, construction and first performance are reported.

  9. The Drift Chamber for the Experiment to Study the Nature of the Confinement

    DOE PAGES

    Berdnikov, Vladimir V.; Somov, S. V.; Pentchev, Lubomir; ...

    2015-01-01

    The GlueX experiment was designed to search for hybrid mesons with exotic quantum numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. The spectrum of these states and their mass splitting from normal mesons may yield information on confinement. The description of the GlueX spectrometer and Forward Drift Chambers (FDC) as a part of track reconstruction system is presented in the text. FDC‘s are multiwire chambers with cathode and anode read-out. The system allows reconstructing tracks of charged particles with ~200mkm accuracy with angles from 20° up to 1°. One of the detector features ismore » 1.64% X0 material amount in the active area. The cathode gain calibration procedure is presented. The results of such calibration using cosmic data and beam data are presented as well.« less

  10. The Drift Chamber for the Experiment to Study the Nature of the Confinement

    SciTech Connect

    Berdnikov, Vladimir V.; Somov, S. V.; Pentchev, Lubomir; Zihlmann, Benedikt

    2015-01-01

    The GlueX experiment was designed to search for hybrid mesons with exotic quantum numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. The spectrum of these states and their mass splitting from normal mesons may yield information on confinement. The description of the GlueX spectrometer and Forward Drift Chambers (FDC) as a part of track reconstruction system is presented in the text. FDC‘s are multiwire chambers with cathode and anode read-out. The system allows reconstructing tracks of charged particles with ~200mkm accuracy with angles from 20° up to 1°. One of the detector features is 1.64% X0 material amount in the active area. The cathode gain calibration procedure is presented. The results of such calibration using cosmic data and beam data are presented as well.

  11. The Drift Chamber for the Experiment to Study the Nature of the Confinement

    NASA Astrophysics Data System (ADS)

    Berdnikov, V. V.; Somov, S. V.; Pentchev, L.; Zihlmann, B.

    The GlueX experiment was designed to search for hybrid mesons with exotic quantum numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. The spectrum of these states and their mass splitting from normal mesons may yield information on confinement. The description of the GlueX spectrometer and Forward Drift Chambers (FDC) as a part of track reconstruction system is presented in the text. FDC's are multiwire chambers with cathode and anode read-out. The system allows reconstructing tracks of charged particles with ∼200mkm accuracy with angles from 20 ̊up to 1 ̊. One of the detector features is 1.64% X0 material amount in the active area. The cathode gain calibration procedure is presented. The results of such calibration using cosmic data and beam data are presented as well.

  12. A Freon-filled bubble chamber for neutron detection in inertial confinement fusion experiments

    NASA Astrophysics Data System (ADS)

    Ghilea, M. C.; Meyerhofer, D. D.; Sangster, T. C.

    2011-03-01

    Neutron imaging is one of the main methods used in inertial confinement fusion experiments to measure the core symmetry of target implosions. Previous studies have shown that bubble chambers have the potential to obtain higher resolution images of the targets for a shorter source-to-target distance than typical scintillator arrays. A bubble chamber for neutron imaging with Freon 115 as the active medium was designed and built for the OMEGA laser system. Bubbles resulting from spontaneous nucleation were recorded. Bubbles resulting from neutron-Freon interactions were observed at neutron yields of 1013 emitted from deuterium-tritium target implosions on OMEGA. The measured column bubble density was too low for neutron imaging on OMEGA but agreed with the model of bubble formation. The recorded data suggest that neutron bubble detectors are a promising technology for the higher neutron yields expected at National Ignition Facility.

  13. A Freon-filled bubble chamber for neutron detection in inertial confinement fusion experiments

    SciTech Connect

    Ghilea, M. C.; Meyerhofer, D. D.; Sangster, T. C.

    2011-03-15

    Neutron imaging is one of the main methods used in inertial confinement fusion experiments to measure the core symmetry of target implosions. Previous studies have shown that bubble chambers have the potential to obtain higher resolution images of the targets for a shorter source-to-target distance than typical scintillator arrays. A bubble chamber for neutron imaging with Freon 115 as the active medium was designed and built for the OMEGA laser system. Bubbles resulting from spontaneous nucleation were recorded. Bubbles resulting from neutron-Freon interactions were observed at neutron yields of 10{sup 13} emitted from deuterium-tritium target implosions on OMEGA. The measured column bubble density was too low for neutron imaging on OMEGA but agreed with the model of bubble formation. The recorded data suggest that neutron bubble detectors are a promising technology for the higher neutron yields expected at National Ignition Facility.

  14. A Freon-filled bubble chamber for neutron detection in inertial confinement fusion experiments.

    PubMed

    Ghilea, M C; Meyerhofer, D D; Sangster, T C

    2011-03-01

    Neutron imaging is one of the main methods used in inertial confinement fusion experiments to measure the core symmetry of target implosions. Previous studies have shown that bubble chambers have the potential to obtain higher resolution images of the targets for a shorter source-to-target distance than typical scintillator arrays. A bubble chamber for neutron imaging with Freon 115 as the active medium was designed and built for the OMEGA laser system. Bubbles resulting from spontaneous nucleation were recorded. Bubbles resulting from neutron-Freon interactions were observed at neutron yields of 10(13) emitted from deuterium-tritium target implosions on OMEGA. The measured column bubble density was too low for neutron imaging on OMEGA but agreed with the model of bubble formation. The recorded data suggest that neutron bubble detectors are a promising technology for the higher neutron yields expected at National Ignition Facility.

  15. A Freon-Filled Bubble Chamber for Neutron Detection in Inertial Confinement Fusion Experiments

    SciTech Connect

    Ghilea, M.C.; Meyerhofer, D.D.; Sangster, T.C.

    2011-03-24

    Neutron imaging is one of the main methods used in inertial confinement fusion experiments to measure the core symmetry of target implosions. Previous studies have shown that bubble chambers have the potential to obtain higher resolution images of the targets for a shorter source-to-target distance than typical scintillator arrays. A bubble chamber for neutron imaging with Freon 115 as the active medium was designed and built for the OMEGA laser system. Bubbles resulting from spontaneous nucleation were recorded. Bubbles resulting from neutron–Freon interactions were observed at neutron yields of 1013 emitted from deuterium–tritium target implosions on OMEGA. The measured column bubble density was too low for neutron imaging on OMEGA but agreed with the model of bubble formation. The recorded data suggest that neutron bubble detectors are a promising technology for the higher neutron yields expected at National Ignition Facility.

  16. A position-sensitive twin ionization chamber for fission fragment and prompt neutron correlation experiments

    NASA Astrophysics Data System (ADS)

    Göök, A.; Geerts, W.; Hambsch, F.-J.; Oberstedt, S.; Vidali, M.; Zeynalov, Sh.

    2016-09-01

    A twin position-sensitive Frisch grid ionization chamber, intended as a fission fragment detector in experiments to study prompt fission neutron correlations with fission fragment properties, is presented. Fission fragment mass and energies are determined by means of the double kinetic energy technique, based on conservation of mass and linear momentum. The position sensitivity is achieved by replacing each anode plate in the standard twin ionization chamber by a wire plane and a strip anode, both readout by means of resistive charge division. This provides information about the fission axis orientation, which is necessary to reconstruct the neutron emission process in the fully accelerated fragment rest-frame. The energy resolution compared to the standard twin ionization chamber is found not to be affected by the modification. The angular resolution of the detector relative to an arbitrarily oriented axis is better than 7° FWHM. Results on prompt fission neutron angular distributions in 235U(n,f) obtained with the detector in combination with an array of neutron scintillation detectors is presented as a proof of principle.

  17. Report of the Next Generation TRIUMF-MTV Experiment Run-IV Using Cylindrical Drift Chamber

    NASA Astrophysics Data System (ADS)

    Tanuma, R.; Seitaibashi, E.; Baba, H.; Kawamura, H.; Behr, J. A.; Onishi, J.; Ninomiya, K.; Pearson, M.; Ikeda, M.; Levy, P.; Narikawa, R.; Openshaw, R.; Tanaka, S.; Saiba, S.; Iguri, T.; Totsuka, Y.; Nakaya, Y.; Murata, J.

    The MTV (Mott polarimetry for T-Violation) experiment is running from 2009 at TRIUMF, which aims to search a large non-standard T-Violation in polarized nuclear beta decay. Existence of a large transverse polarization of electrons emitted from polarized Li-8 nuclei, which are produced at TRIUMF-ISAC and stopped inside an aluminum stopper, is investigated. We utilize a Mott polarimeter consists of a CDC (Cylindrical Drift Chamber), measuring backward scattering left-right asymmetry from a thin lead analyzer foil. In this paper, results from the final performance test run using CDC performed in 2012 are described.

  18. Multiwire proportional chambers in M1 and M3 spectrometers of charmed baryon experiment (E781) at Fermilab

    SciTech Connect

    Kaya, Mithat; /Iowa U.

    1997-08-01

    The status of the multiwire proportional chambers in the FERMILAB E781 experiment and a general description of the readout system are given. This essay will describe the system of multiwire proportional chambers (MWPC) that are part of the Fermilab experiment E781 setup. Multiwire proportional chambers are often used in particle physics experiments because they can determine the position of charged particles very accurately (less than a millimeter). The E781 experiment which is also called SELEX (SEgmented LargE-X) is a spectrometer designed to study the production and decay of charmed baryons. MWPCs are part of the 3-stage charged particle spectrometer (Figure 1). Each spectrometer stage includes a bending magnet and chambers. More information about E781 experiment is given in the Appendix. In the following, some basic concepts of MWPCs will be given briefly. After that the multiwire proportional chambers (M1PWC and M3PWC) that are used in the E781 fixed target experiment will be described. Then a general description of the readout system for both M1PWC and M3PWC setups will follow. Finally the tests done on both sets of chambers will be explained in detail.

  19. Continuous measurements of H2 and CO deposition onto soil: a laboratory soil chamber experiment

    NASA Astrophysics Data System (ADS)

    Ghosh, P.; Eiler, J.; Smith, N. V.; Thrift-Viveros, D. L.

    2004-12-01

    Hydrogen uptake in soil is the largest single component of the global budget of atmospheric H2, and is the most important parameter for predicting changes in atmospheric concentration with future changing sources (anthropogenic and otherwise). The rate of hydrogen uptake rate by soil is highly uncertain [1]. As a component of the global budget, it is simply estimated as the difference among estimates for other recognized sources and sinks, assuming the atmosphere is presently in steady state. Previous field chamber experiments [2] show that H2 deposition velocity varies complexly with soil moisture level, and possibly with soil organic content and temperature. We present here results of controlled soil chamber experiments on 3 different soil blocks (each ~20 x ~20 x ~21 cm) with a controlled range of moisture contents. All three soils are arid to semi arid, fine grained, and have organic contents of 10-15%. A positive air pressure (slightly higher than atmospheric pressure) and constant temperature and relative humidity was maintained inside the 10.7 liter, leak-tight plexiglass chamber, and a stream of synthetic air with known H2 concentration was continuously bled into the chamber through a needle valve and mass flow meter. H2, CO and CO2 concentrations were continuously analyzed in the stream of gas exiting the chamber, using a TA 3000 automated Hg-HgO reduced gas analyzer and a LI-820 CO2 gas analyzer. Our experimental protocol involved waiting until concentrations of analyte gases in the exiting gas stream reached a steady state, and documenting how that steady state varied with various soil properties and the rate at which gases were delivered to the chamber. The rate constants for H2 and CO consumption in the chamber were measured at several soil moisture contents. The calculated deposition velocities of H2 and CO into the soil are positively correlated with steady-state concentrations, with slopes and curvatures that vary with soil type and moisture level

  20. Simulation of ion chamber signals in the n+3 He -> p + t experiment

    NASA Astrophysics Data System (ADS)

    Coppola, Christopher; n3He Collaboration

    2017-01-01

    The parity violating proton directional asymmetry from the capture of polarized neutrons on 3He was measured with a pulsed neutron beam at the Spallation Neutron Source at Oak Ridge National Laboratory. The target is an ion chamber with 3He at 0.476 atmosphere. Signal wires in the chamber have different sensitivities to the physics asymmetry, depdendent on their location and the configuration of the experiment. These geometry factors must be determined by simulation. In addition, simulation estimates the statistical precision of the experiment, optimizes configuration variables, and assists with systematic analysis. To achieve the most accurate simulation of the detector signals, a custom simulation was written in C++ using weighted variables and taking advantage of parallel execution. The phsyics inputs to the simulation came from measurements of the neutron phase space, ENDF cross sections, and PSTAR ionization data. A cell model was applied to combine this physics to produce an accurate simulation of the experimental data. This simulation can be used to calculate accurate and tunable geometry factors, and to produce desired quanities for use in optimization and analysis.

  1. The Charged Pion Polarizability Experiment at the Thomas Jefferson National Accelerator Facility: Developing Muon Chambers and Experiment Simulation

    NASA Astrophysics Data System (ADS)

    Johnston, Bobby; Miskimen, Rory; Downing, Matthew; Haughwout, Christian; Schick, Andrew; Jefferson Lab Hall D Collaboration

    2016-09-01

    The Thomas Jefferson National Accelerator Facility has proposed to make a precision measurement of the charged pion polarizability through measurements of γγ ->π+π- cross sections using the new GlueX detector. This experiment will have a large muon background which must be filtered out of the pion signal. For this issue we are developing an array of Multi-Wire Proportional Chambers (MWPCs) that will allow the pions to be identified from the muons, permitting a precise measurement of the polarizability. Small (1:8 scale) and medium (1:5 scale) sized prototypes have been constructed and tested, and a full scale prototype is currently being assembled. MWPC electronics were developed and tested to amplify the signal from the detection chamber, and were designed to interface with Jefferson Lab's existing data acquisition system. In order to construct the detectors, a class 10,000 clean room was assembled specifically for this purpose. Lastly, Geant4 software is being used to run Monte Carlo simulations of the experiment. This allows us to determine the optimal orientation and number of MWPCs needed for proper filtering which will indicate how many more MWPCs must be built before the experiment can be run. Department of Energy.

  2. Development of a multipurpose vacuum chamber for serial optical and diffraction experiments with free electron laser radiation.

    PubMed

    Rajkovic, I; Hallmann, J; Grübel, S; More, R; Quevedo, W; Petri, M; Techert, S

    2010-04-01

    In this paper we present a development of a multipurpose vacuum chamber which primal function is to be used in pump/probe experiments with free electron laser (FEL) radiation. The chamber is constructed for serial diffraction and serial spectroscopy allowing a fast exchange of samples during the measurement process. For the fast exchange of samples, liquid jet systems are used. Both applications, utilizing soft x-ray FEL pulses as pump and optical laser pulses as probe and vice versa are documented. Experiments with solid samples as well as the liquid jet samples are presented. When working with liquid jets, a system of automatically refilled liquid traps for capturing liquids has been developed in order to ensure stable vacuum conditions. Differential pumping stages are placed in between the FEL beamline and the experimental chamber so that working pressure in the chamber can be up to four orders of magnitude higher than the pressure in the FEL beamline.

  3. Two Years of Industrial Experience in the Use of a Small, Direct Field Acoustic Chamber

    NASA Astrophysics Data System (ADS)

    Saggini, Nicola; Di Pietro, Vincenzo; Poulain, Nicolas; Herzog, Philippe

    2012-07-01

    Within Thales Alenia Space - Italy small satellite Assembly Integration and Test (AIT) plant, the need to develop a suitable facility for spacecraft acoustic noise test has arisen, with additional constraints posed by the necessity of a low impact on the existing building layout, low cost of procurement and operations, while maintaining a high reliability of the system for a theoretical maximum throughput of one test per week over an extended period of time, e.g. six months. The needs have been answered by developing a small (~40 m3 test volume), direct field (DF A T) acoustic test chamber, christened “Alpha Cabin”, where noise generation is achieved by means of commercial audio drivers equipped with custom enclosures. The paper starts with a brief presentation of the main characteristics of the system, but then concentrates on the lessons learnt and return of experience from the tests conducted in more than two years of continuous use. Starting from test article structural responses and their comparison with reverberant chambers, properties of the acoustic field and their implications on the former are analyzed.

  4. Semi-automated operation of Mars Climate Simulation chamber - MCSC modelled for biological experiments

    NASA Astrophysics Data System (ADS)

    Tarasashvili, M. V.; Sabashvili, Sh. A.; Tsereteli, S. L.; Aleksidze, N. D.; Dalakishvili, O.

    2017-10-01

    The Mars Climate Simulation Chamber (MCSC) (GEO PAT 12 522/01) is designed for the investigation of the possible past and present habitability of Mars, as well as for the solution of practical tasks necessary for the colonization and Terraformation of the Planet. There are specific tasks such as the experimental investigation of the biological parameters that allow many terrestrial organisms to adapt to the imitated Martian conditions: chemistry of the ground, atmosphere, temperature, radiation, etc. MCSC is set for the simulation of the conduction of various biological experiments, as well as the selection of extremophile microorganisms for the possible Settlement, Ecopoesis and/or Terraformation purposes and investigation of their physiological functions. For long-term purposes, it is possible to cultivate genetically modified organisms (e.g., plants) adapted to the Martian conditions for future Martian agriculture to sustain human Mars missions and permanent settlements. The size of the chamber allows preliminary testing of the functionality of space-station mini-models and personal protection devices such as space-suits, covering and building materials and other structures. The reliability of the experimental biotechnological materials can also be tested over a period of years. Complex and thorough research has been performed to acquire the most appropriate technical tools for the accurate engineering of the MCSC and precious programmed simulation of Martian environmental conditions. This paper describes the construction and technical details of the equipment of the MCSC, which allows its semi-automated, long-term operation.

  5. Studies of particle interactions in bubble chamber, spark chambers and counter experiments: Task P. Annual progress report

    SciTech Connect

    Jones, L.M.; Holloway, L.; O'Halloran, T.A. Jr.; Simmons, R.O.

    1983-07-01

    Our current work reflects the general aim of this task, which is to calculate phenomenological theories of interest to present experiments. Recently, this has emphasized the jet calculus approach to properties of quark and gluon jets. Progress is reviewed.

  6. Web-based monitoring tools for Resistive Plate Chambers in the CMS experiment at CERN

    NASA Astrophysics Data System (ADS)

    Kim, M. S.; Ban, Y.; Cai, J.; Li, Q.; Liu, S.; Qian, S.; Wang, D.; Xu, Z.; Zhang, F.; Choi, Y.; Kim, D.; Goh, J.; Choi, S.; Hong, B.; Kang, J. W.; Kang, M.; Kwon, J. H.; Lee, K. S.; Lee, S. K.; Park, S. K.; Pant, L. M.; Mohanty, A. K.; Chudasama, R.; Singh, J. B.; Bhatnagar, V.; Mehta, A.; Kumar, R.; Cauwenbergh, S.; Costantini, S.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Ocampo, A.; Poyraz, D.; Salva, S.; Thyssen, F.; Tytgat, M.; Zaganidis, N.; Doninck, W. V.; Cabrera, A.; Chaparro, L.; Gomez, J. P.; Gomez, B.; Sanabria, J. C.; Avila, C.; Ahmad, A.; Muhammad, S.; Shoaib, M.; Hoorani, H.; Awan, I.; Ali, I.; Ahmed, W.; Asghar, M. I.; Shahzad, H.; Sayed, A.; Ibrahim, A.; Aly, S.; Assran, Y.; Radi, A.; Elkafrawy, T.; Sharma, A.; Colafranceschi, S.; Abbrescia, M.; Calabria, C.; Colaleo, A.; Iaselli, G.; Loddo, F.; Maggi, M.; Nuzzo, S.; Pugliese, G.; Radogna, R.; Venditti, R.; Verwilligen, P.; Benussi, L.; Bianco, S.; Piccolo, D.; Paolucci, P.; Buontempo, S.; Cavallo, N.; Merola, M.; Fabozzi, F.; Iorio, O. M.; Braghieri, A.; Montagna, P.; Riccardi, C.; Salvini, P.; Vitulo, P.; Vai, I.; Magnani, A.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Rodozov, M.; Sultanov, G.; Vutova, M.; Stoykova, S.; Hadjiiska, R.; Ibargüen, H. S.; Morales, M. I. P.; Bernardino, S. C.; Bagaturia, I.; Tsamalaidze, Z.; Crotty, I.

    2014-10-01

    The Resistive Plate Chambers (RPC) are used in the CMS experiment at the trigger level and also in the standard offline muon reconstruction. In order to guarantee the quality of the data collected and to monitor online the detector performance, a set of tools has been developed in CMS which is heavily used in the RPC system. The Web-based monitoring (WBM) is a set of java servlets that allows users to check the performance of the hardware during data taking, providing distributions and history plots of all the parameters. The functionalities of the RPC WBM monitoring tools are presented along with studies of the detector performance as a function of growing luminosity and environmental conditions that are tracked over time.

  7. Parallel readout multiwire proportional chambers for time resolved X-ray diffraction experiments

    NASA Astrophysics Data System (ADS)

    Faruqi, A. R.; Bond, C. C.

    1980-10-01

    Linear position sensitive detectors have been used for a number of years in X-ray diffraction studies from various types of muscle under different physiological conditions. Such detectors are mainly based on either an internal (RC) delay line or an external (LC) delay line for decoding positional information; the counting speed of the detectors is optimally matched to the available photon flux from laboratory based X-ray cameras. However, X-ray cameras based on synchrotron radiation provide photon fluxes which are greater by about three orders of magnitude. We describe in this paper an X-ray detection system based on parallel readout from a multiwire proportional chamber which offers high counting speeds and is designed to perform time slicing experiments with time resolutions down to 1 ms.

  8. ASD IC for the thin gap chambers in the LHC Atlas experiment

    SciTech Connect

    Sasaki, Osamu; Yoshida, Mitsuhiro

    1999-12-01

    An amplifier-shaper-discriminator (ASD) chip was designed and built for Thin Gap Chambers in the forward muon trigger system of the LHC Atlas experiment. The ASD IC uses SONY Analog Master Slice bipolar technology. The IC contains 4 channels in a QFP48 package. The gain of its first stage (preamplifier) is approximately 0.8V/pC and output from the preamplifier is received by a shaper (main-amplifier) with a gain of 7. The baseline restoration circuit is incorporated in the main-amplifier. The threshold voltage for discriminator section is common to the 4 channels and their digital output level is LVDS-compatible. The IC also has analog output of the preamplifier. The equivalent noise charge at input capacitance of 150 pF is around 7,500 electrons. The power dissipation with LDVS outputs (100 {Omega} load) is 59mW/ch.

  9. Experiences from nonevaporable getter-coated vacuum chambers at the MAX II synchrotron light source

    SciTech Connect

    Hansson, A.; Wallen, E.; Berglund, M.; Kersevan, R.; Hahn, M.

    2010-03-15

    Vacuum chambers coated with nonevaporable getter (NEG) materials have been used in straight sections of synchrotron light sources for the past 10 years. The MAX II storage ring, where four NEG-coated insertion device vacuum chambers and three NEG-coated dipole vacuum chambers have been installed, is the first synchrotron light source to also use NEG-coated dipole vacuum chambers. In connection with the installation of the latest two NEG-coated dipole chambers in April 2009, the evolution of the pressure and lifetime-limiting effects in MAX II has been determined from measurements with movable scrapers. The results have been compared with results from scraper measurements done in 2003, before any NEG-coated vacuum chambers were installed in the storage ring. Less than three months after the installation of the latest dipole chambers the vacuum system in MAX II was performing well with a pressure already lower than the pressure measured in 2003.

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

    NASA Astrophysics Data System (ADS)

    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

  11. Constraining uncertainties in particle-wall deposition correction during SOA formation in chamber experiments

    NASA Astrophysics Data System (ADS)

    Nah, Theodora; McVay, Renee C.; Pierce, Jeffrey R.; Seinfeld, John H.; Ng, Nga L.

    2017-02-01

    The effect of vapor-wall deposition on secondary organic aerosol (SOA) formation has gained significant attention; however, uncertainties in experimentally derived SOA mass yields due to uncertainties in particle-wall deposition remain. Different approaches have been used to correct for particle-wall deposition in SOA formation studies, each having its own set of assumptions in determining the particle-wall loss rate. In volatile and intermediate-volatility organic compound (VOC and IVOC) systems in which SOA formation is governed by kinetically limited growth, the effect of vapor-wall deposition on SOA mass yields can be constrained by using high surface area concentrations of seed aerosol to promote the condensation of SOA-forming vapors onto seed aerosol instead of the chamber walls. However, under such high seed aerosol levels, the presence of significant coagulation may complicate the particle-wall deposition correction. Here, we present a model framework that accounts for coagulation in chamber studies in which high seed aerosol surface area concentrations are used. For the α-pinene ozonolysis system, we find that after accounting for coagulation, SOA mass yields remain approximately constant when high seed aerosol surface area concentrations ( ≥ 8000 µm2 cm-3) are used, consistent with our prior study (Nah et al., 2016) showing that α-pinene ozonolysis SOA formation is governed by quasi-equilibrium growth. In addition, we systematically assess the uncertainties in the calculated SOA mass concentrations and yields between four different particle-wall loss correction methods over the series of α-pinene ozonolysis experiments. At low seed aerosol surface area concentrations (< 3000 µm2 cm-3), the SOA mass yields at peak SOA growth obtained from the particle-wall loss correction methods agree within 14 %. However, at high seed aerosol surface area concentrations ( ≥ 8000 µm2 cm-3), the SOA mass yields at peak SOA growth obtained from different particle

  12. A review of chamber experiments for determining specific emission rates and investigating migration pathways of flame retardants

    NASA Astrophysics Data System (ADS)

    Rauert, Cassandra; Lazarov, Borislav; Harrad, Stuart; Covaci, Adrian; Stranger, Marianne

    2014-01-01

    The widespread use of flame retardants (FRs) in indoor products has led to their ubiquitous distribution within indoor microenvironments with many studies reporting concentrations in indoor air and dust. Little information is available however on emission of these compounds to air, particularly the measurement of specific emission rates (SERs), or the migration pathways leading to dust contamination. Such knowledge gaps hamper efforts to develop understanding of human exposure. This review summarizes published data on SERs of the following FRs released from treated products: polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol-A (TBBPA), novel brominated flame retardants (NBFRs) and organophosphate flame retardants (PFRs), including a brief discussion of the methods used to derive these SERs. Also reviewed are published studies that utilize emission chambers for investigations/measurements of mass transfer of FRs to dust, discussing the chamber configurations and methods used for these experiments. A brief review of studies investigating correlations between concentrations detected in indoor air/dust and possible sources in the microenvironment is included along with efforts to model contamination of indoor environments. Critical analysis of the literature reveals that the major limitations with utilizing chambers to derive SERs for FRs arise due to the physicochemical properties of FRs. In particular, increased partitioning to chamber surfaces, airborne particles and dust, causes loss through “sink” effects and results in long times to reach steady state conditions inside the chamber. The limitations of chamber experiments are discussed as well as their potential for filling gaps in knowledge in this area.

  13. Assessment of SAPRC07 with updated isoprene chemistry against outdoor chamber experiments

    NASA Astrophysics Data System (ADS)

    Chen, Yuzhi; Sexton, Kenneth G.; Jerry, Roger E.; Surratt, Jason D.; Vizuete, William

    2015-03-01

    Isoprene, the most emitted non-methane hydrocarbon, is known to influence ozone (O3) formation in urban areas rich with biogenic emissions. To keep up with the recent advance on isoprene oxidation chemistry including the identification of isoprene epoxydiols (IEPOX) as a precursor to secondary organic aerosol (SOA), Xie et al. (2013) updated the SAPRC (Statewide Air Pollution Research Center)-07 chemical mechanism. It is currently unknown how the Xie modification of SAPRC07 impacts the ability of the model to predict O3. In this study we will evaluate the Xie mechanism with simulations of 24 isoprene experiments from the UNC Dual Gas-phase Chamber. Our results suggest that the new mechanism increases NOx (nitrogen oxides) inter-conversion and produces more O3 than SAPRC07 for all experiments. In lower-NOx experiments, the new mechanism worsens O3 performance in the wrong direction, increasing bias from 4.92% to 9.44%. We found increased NOx recycling from PANs accounts for that. This could be explained by more PANs made due to increased first generation volatile organic compound (VOC) products and hydroxyl radical (OH) production.

  14. Performance of the Cylindrical Drift Chamber and the Inner Plastic Scintillator in the BGOegg experiment

    NASA Astrophysics Data System (ADS)

    Shibukawa, Takuya; Masumoto, Shinichi; Ozawa, Kyoichiro; Ohnishi, Hiroaki; Muramatsu, Norihito; Ishikawa, Takatsugu; Miyabe, Manabu; Tsuchikawa, Yusuke; Yamazaki, Ryuji; Matsumura, Yuji; Mizutani, Keigo; Hashimoto, Toshikazu; Hamano, Hirotomo; LEPS2/BGOegg Collaboration

    2014-09-01

    Properties of vector mesons, such as ω mesons, in nucleus are intensively measured to study interactions between mesons and nuclear medium. To study ω meson properties in nuclei, we search for the nuclear ω bound states in the LEPS2/BGOegg experiment at SPring-8. If a strongly bounded ω state exists and binding energy is measured, it gives a phenomenological information about interactions between ω meson and nuclei. ω meson is produced using the GeV γ rays at SPring-8/LEPS2 beamline. The ω bound state is searched from the missing mass measurements of forward going protons. ω meson production is identified by detecting γ and proton from ωN --> N* --> γp or ωN --> γΔ --> γπ p reaction. In the BGOegg experiment, charged particles are detected by Cylindrical Drift Chamber(CDC) and Inner Plastic Scintillators (IPS) around the target. CDC has 4 layers of stereo wires and each layer has 72 sense wires. IPS consists of 30 plastic scintillators. In this talk, the performance of CDC and IPS are described in detail. Properties of vector mesons, such as ω mesons, in nucleus are intensively measured to study interactions between mesons and nuclear medium. To study ω meson properties in nuclei, we search for the nuclear ω bound states in the LEPS2/BGOegg experiment at SPring-8. If a strongly bounded ω state exists and binding energy is measured, it gives a phenomenological information about interactions between ω meson and nuclei. ω meson is produced using the GeV γ rays at SPring-8/LEPS2 beamline. The ω bound state is searched from the missing mass measurements of forward going protons. ω meson production is identified by detecting γ and proton from ωN --> N* --> γp or ωN --> γΔ --> γπ p reaction. In the BGOegg experiment, charged particles are detected by Cylindrical Drift Chamber(CDC) and Inner Plastic Scintillators (IPS) around the target. CDC has 4 layers of stereo wires and each layer has 72 sense wires. IPS consists of 30 plastic

  15. The central drift chamber for the D0 experiment: Design, construction and test

    SciTech Connect

    Behnke, Ties

    1989-08-01

    A cylindrical drift chamber has been designed and built at the State University of New York at Stony Brook. This chamber is to be installed in the D0 detector which is being completed at the Fermi National Accelerator. In this dissertation the design, construction and testing of this chamber are described. The characteristic features of this chamber are cells formed by solid walls and a modular structure. Much discussion is given to the performance of and results from a chamber made from three final modules which was installed in the D0 interaction region during the 1988/1989 collider run. Using this chamber proton anti-proton interactions were measured at the D0 interaction point.

  16. Atmospherically relevant experiments on new particle formation in the CERN CLOUD chamber (Invited)

    NASA Astrophysics Data System (ADS)

    Baltensperger, U.; Almeida, J.; Riccobono, F.; Schobesberger, S.; Kirkby, J.

    2013-12-01

    It is generally agreed that sulfuric acid is a major player in atmospheric new particle formation, however, the concentrations of sulfuric acid in the boundary layer of the ambient atmosphere are not sufficient for pure binary nucleation together with water. Therefore, other ingredients are needed to explain the observed new particle formation rates. A two-fold approach is required here: on the one hand field studies providing evidence for such additional components are to be performed, and on the other hand, laboratory experiments need to investigate the effects of such additional components. The latter has for a long time been hampered by our inability to provide a sufficiently clean environment for such experiments. With the CLOUD chamber at CERN, a number of such experiments have been performed, giving insight into the role of such additional components. Ammonia was shown to enhance the nucleation rates by several orders of magnitude compared to pure binary nucleation, however, was still insufficient to match the observed nucleation rates in the boundary layer (Kirkby et al., 2011). This paper will report on the results of experiments using dimethylamine, or oxidation products of either pinanediol or alpha-pinene as additional components. The experiments were performed in the presence or absence of ions from galactic cosmic rays, as well as with an enhanced ion concentration achieved with a pion bean provided by the CERN Proton Synchrotron. The formation of charged and neutral clusters as well as of new particles was followed by a wide variety of instruments, providing insight into the mechanism of new particle formation. Reference: Kirkby, J., et al., Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation, Nature 476, 429-433 (2011).

  17. Atmospheric photochemistry of aromatic hydrocarbons: OH budgets during SAPHIR chamber experiments

    NASA Astrophysics Data System (ADS)

    Nehr, S.; Bohn, B.; Dorn, H.-P.; Fuchs, H.; Häseler, R.; Hofzumahaus, A.; Li, X.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2014-07-01

    Current photochemical models developed to simulate the atmospheric degradation of aromatic hydrocarbons tend to underestimate OH radical concentrations. In order to analyse OH budgets, we performed experiments with benzene, toluene, p-xylene and 1,3,5-trimethylbenzene in the atmosphere simulation chamber SAPHIR. Experiments were conducted under low-NO conditions (typically 0.1-0.2 ppb) and high-NO conditions (typically 7-8 ppb), and starting concentrations of 6-250 ppb of aromatics, dependent on OH rate constants. For the OH budget analysis a steady-state approach was applied in which OH production and destruction rates (POH and DOH) have to be equal. The POH were determined from measurements of HO2, NO, HONO, and O3 concentrations, considering OH formation by photolysis and recycling from HO2. The DOH were calculated from measurements of the OH concentrations and total OH reactivities. The OH budgets were determined from DOH/POH ratios. The accuracy and reproducibility of the approach were assessed in several experiments using CO as a reference compound where an average ratio DOH/POH = 1.13 ± 0.19 was obtained. In experiments with aromatics, these ratios ranged within 1.1-1.6 under low-NO conditions and 0.9-1.2 under high-NO conditions. The results indicate that OH budgets during photo-oxidation experiments with aromatics are balanced within experimental accuracies. Inclusion of a further, recently proposed OH production via HO2 + RO2 reactions led to improvements under low-NO conditions but the differences were small and insignificant within the experimental errors.

  18. Atmospheric photochemistry of aromatic hydrocarbons: OH budgets during SAPHIR chamber experiments

    NASA Astrophysics Data System (ADS)

    Nehr, S.; Bohn, B.; Dorn, H.-P.; Fuchs, H.; Häseler, R.; Hofzumahaus, A.; Li, X.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2014-03-01

    Current photochemical models developed to simulate the atmospheric degradation of aromatic hydrocarbons tend to underestimate OH radical concentrations. In order to analyse OH budgets, we performed experiments with benzene, toluene, p-xylene, and 1,3,5-trimethylbenzene in the atmosphere simulation chamber SAPHIR. Experiments were conducted under low-NO conditions (typically 0.1-0.2 ppb) and high-NO conditions (typically 7-8 ppb), and starting concentrations of 6-250 ppb of aromatics, dependent on OH rate constants. For the OH budget analysis a steady-state approach was applied where OH production and destruction rates (POH and DOH) have to be equal. The POH were determined from measurements of HO2, NO, HONO, and O3 concentrations, considering OH formation by photolysis and recycling from HO2. The DOH were calculated from measurements of the OH concentrations and total OH reactivities. The OH budgets were determined from DOH / POH ratios. The accuracy and reproducibility of the approach were assessed in several experiments using CO as a reference compound where an average ratio DOH / POH = 1.13 ± 0.19 was obtained. In experiments with aromatics, these ratios ranged within 1.1-1.6 under low-NO conditions and 0.9-1.2 under high-NO conditions. The results indicate that OH budgets during photo-oxidation experiments with aromatics are balanced within experimental accuracies. Inclusion of a further, recently proposed OH production via HO2 + RO2 reactions led to improvements under low-NO conditions but the differences were small and insignificant within the experimental errors.

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

    SciTech Connect

    Rickards, J.; Golzarri, J. I.; Espinosa, G.; Vázquez-López, C.

    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.

  20. Calibration of the Sweeper Chamber Charged-Particle Detectors for the LISA Commissioning Experiment

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, J.; Grovom, A.; Rogers, W.; MoNA Collaboration

    2011-10-01

    The new LISA (Large-area multi-Institutional Scintillator Array) neutron detector array, designed to be used in conjunction with MoNA (Modular Neutron Array) was recently commissioned at the NSCL in an experiment designed to investigate excited states of neutron-rich Oxygen isotopes near the neutron drip-line. Charged fragments resulting from the neutron decays were swept out of the beam direction by the Sweeper Magnet after which they passed through a series of charged-particle detectors for fragment trajectory and energy determination. In order to achieve isotope separation and identification at the focal plane, which is then used to reconstruct the invariant mass of the unbound states, precise determinations of the fragment and neutron energies and trajectories are required. To correct for time-drifts in the charge-particle detectors that develop over the entire length of the experiment, Root C++ macros were developed to analyze and precisely correct for these detector drifts to within few tenths of a nanosecond. Root macros were also developed to position calibrate the ion chamber and CRDC's. Results for the LISA commissioning run will be presented. Work supported by NSF grant PHY-1101745.

  1. The Resistive Plate Chambers of the ATLAS experiment:. performance studies on Calibration Stream

    NASA Astrophysics Data System (ADS)

    Mazzaferro, Luca

    2012-08-01

    ATLAS (A Toroidal LHC ApparatuS) is one of the four experiments installed on the hadron-hadron collider LHC at CERN. It is a general purpose experiment, with a physics program which spans from the search for the Higgs Boson to the search of physics Beyond the Standard Model (BSM). An integrated luminosity of about 5 fb-1 is expected to be reached by the end of 2011. The Resistive Plate Chambers, installed in the barrel region, are used to provide the first muon level trigger, and cover an area of 16000 m2, readout by about 350000 electronic channels. To ensure optimal trigger performance, the RPC operational parameters like cluster size, efficiency and spatial resolution are constantly monitored. In order to achieve the desired precision, the data used for the analysis are extracted directly from the second level of the trigger, hence assuring very high statistics. This dedicated event stream, called Calibration Stream, is sent automatically to the RPC Calibration Center in Naples. Here the analysis is performed using an automatic tool tightly integrated in the ATLAS GRID environment, the Local Calibration Data Splitter (LCDS), which configures and manages all the operations required by the analysis (e.g. software environment initialization, grid jobs configuration and submission, data saving and retrieval, etc). The monitored RPC operational parameters, the performance analysis and the LCDS will be presented.

  2. Beam test results on double-gap resistive plate chambers proposed for CMS experiment

    NASA Astrophysics Data System (ADS)

    Abbrescia, M.; Bruno, G.; Colaleo, A.; Iaselli, G.; Lamanna, G.; Loddo, F.; Maggi, M.; Marangelli, B.; Natali, S.; Nuzzo, S.; Pugliese, G.; Ranieri, A.; Romano, F.; Gianini, G.; Ratti, S. P.; Vitulo, P.

    Resistive Plate Chambers were tested in a muon and pion beam to study the performances at different running conditions. Results on a first chamber built without the linseed oil treatment of the bakelite surfaces are presented together with an evaluation of the local effects due to the spacers. These results are extrapolated to the conditions expected at LHC.

  3. Design of Plant Gas Exchange Experiments in a Variable Pressure Growth Chamber

    NASA Technical Reports Server (NTRS)

    Corey, Kenneth A.

    1996-01-01

    Sustainable human presence in extreme environments such as lunar and martian bases will require bioregenerative components to human life support systems where plants are used for generation of oxygen, food, and water. Reduced atmospheric pressures will be used to minimize mass and engineering requirements. Few studies have assessed the metabolic and developmental responses of plants to reduced pressure and varied oxygen atmospheres. The first tests of hypobaric pressures on plant gas exchange and biomass production at the Johnson Space Center will be initiated in January 1996 in the Variable Pressure Growth Chamber (VPGC), a large, closed plant growth chamber rated for 10.2 psi. Experiments were designed and protocols detailed for two complete growouts each of lettuce and wheat to generate a general database for human life support requirements and to answer questions about plant growth processes in reduced pressure and varied oxygen environments. The central objective of crop growth studies in the VPGC is to determine the influence of reduced pressure and reduced oxygen on the rates of photosynthesis, dark respiration, evapotranspiration and biomass production of lettuce and wheat. Due to the constraint of one experimental unit, internal controls, called pressure transients, will be used to evaluate rates of CO2 uptake, O2 evolution, and H2O generation. Pressure transients will give interpretive power to the results of repeated growouts at both reduced and ambient pressures. Other experiments involve the generation of response functions to partial pressures of O2 and CO2 and to light intensity. Protocol for determining and calculating rates of gas exchange have been detailed. In order to build these databases and implement the necessary treatment combinations in short time periods, specific requirements for gas injections and removals have been defined. A set of system capability checks will include determination of leakage rates conducted prior to the actual crop

  4. Utilizing ARC EMCS Seedling Cassettes as Highly Versatile Miniature Growth Chambers for Model Organism Experiments

    NASA Technical Reports Server (NTRS)

    Freeman, John L.; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David; Reinsch, S.; DeSimone, Julia C.; Myers, Zachary A.

    2014-01-01

    The aim of our ground testing was to demonstrate the capability of safely putting specific model organisms into dehydrated stasis, and to later rehydrate and successfully grow them inside flight proven ARC EMCS seedling cassettes. The ARC EMCS seedling cassettes were originally developed to support seedling growth during space flight. The seeds are attached to a solid substrate, launched dry, and then rehydrated in a small volume of media on orbit to initiate the experiment. We hypothesized that the same seedling cassettes should be capable of acting as culture chambers for a wide range of organisms with minimal or no modification. The ability to safely preserve live organisms in a dehydrated state allows for on orbit experiments to be conducted at the best time for crew operations and more importantly provides a tightly controlled physiologically relevant growth experiment with specific environmental parameters. Thus, we performed a series of ground tests that involved growing the organisms, preparing them for dehydration on gridded Polyether Sulfone (PES) membranes, dry storage at ambient temperatures for varying periods of time, followed by rehydration. Inside the culture cassettes, the PES membranes were mounted above blotters containing dehydrated growth media. These were mounted on stainless steel bases and sealed with plastic covers that have permeable membrane covered ports for gas exchange. The results showed we were able to demonstrate acceptable normal growth of C.elegans (nematodes), E.coli (bacteria), S.cerevisiae (yeast), Polytrichum (moss) spores and protonemata, C.thalictroides (fern), D.discoideum (amoeba), and H.dujardini (tardigrades). All organisms showed acceptable growth and rehydration in both petri dishes and culture cassettes initially, and after various time lengths of dehydration. At the end of on orbit ISS European Modular Cultivation System experiments the cassettes could be frozen at ultra-low temperatures, refrigerated, or chemically

  5. Plasma chamber testing of APSA coupons for the SAMPIE flight experiment

    NASA Technical Reports Server (NTRS)

    Hillard, G. Barry

    1993-01-01

    Among the solar cell technologies to be tested in space as part of the Solar Array Module Plasma Interactions Experiment (SAMPIE) will be the Advanced Photovoltaic Solar Array (APSA). Several prototype twelve cell coupons were built for NASA using different blanket materials and mounting techniques. The first conforms to the baseline design for APSA which calls for the cells to be mounted on a carbon loaded Kapton blanket to control charging in GEO. When deployed, this design has a flexible blanket supported around the edges. A second coupon was built with the cells mounted on Kapton-H, which was in turn cemented to a solid aluminum substrate. A final coupon was identical to the latter but used germanium coated Kapton to control atomic oxygen attack in LEO. Ground testing of these coupons in a plasma chamber showed considerable differences in plasma current collection. The Kapton-H coupon demonstrated current collection consistent with exposed interconnects and some degree of cell snapover. The other two coupons experienced anomalously large collection currents. This behavior is believed to a consequence of enhanced plasma sheaths supported by the weakly conducting carbon and germanium used in these coupons. The results reported here are the first experimental evidence that the use of such materials can result in power losses to high voltage space power systems.

  6. Radon emanation chamber: High sensitivity measurements for the SuperNEMO experiment

    SciTech Connect

    Soulé, B.; Collaboration: SuperNEMO Collaboration; and others

    2013-08-08

    Radon is a well-known source of background in ββ0ν experiments due to the high Q{sub β} value of one of its daughter nucleus, {sup 214}Bi. The SuperNEMO collaboration requires a maximum radon contamination of 0.1 mBq/m{sup 3} inside its next-generation double beta decay detector. To reach such a low activity, a drastic screening process has been set for the selection of the detector's materials. In addition to a good radiopurity, a low emanation rate is required. To test this parameter, a Radon Emanation Setup is running at CENBG. It consists in a large emanation chamber connected to an electrostatic detector. By measuring large samples and having a low background level, this setup reaches a sensitivity of a few μ Bq. m{sup −2}. d{sup −1} and is able to qualify materials used in the construction of the SuperNEMO detector.

  7. Design of Drift Chamber 5 for the COMPASS II polarized Drell-Yan experiment

    NASA Astrophysics Data System (ADS)

    Mallon, James; Compass Dc5 Team

    2014-09-01

    The COMPASS project is a fixed-target nuclear physics experiment at CERN which explores the internal structure of the proton, and COMPASS ll's polarized Drell-Yan experiments will be exploring the quark angular momentum contribution to the spin of the proton through Semi-Inclusive Deep Inelastic Scattering. As a part of this process, Drift Chamber 5 (DC5), based on DC4 built by CEA-Saclay, must be constructed to replace a faulty straw chamber. The 23 total frames of DC5 have an outside measurement of 2.94 m by 2.54 m, with the 8 anode frames having a total of 4616 >2 m-long wires, giving a detection region of 4.19 m2 with a resolution of 200 microns. These wire planes are orientated with the x- and x'-frames in the vertical x-direction, the y- & y'-frames in the horizontal y-direction, the u- & u'- frames offset +10 deg from the vertical x-direction, and the v- &v'-frames offset -10 deg from the vertical x-direction, and are strung with Ø100 micron field wires and Ø20 micron sense wires. In order to solve left-right ambiguity, x', y', u', and v' are shifted by 4mm, or one drift cell. The x- and y-frames have 513 wires strung across them, with the field wires at 400 g of tension, the sense wires at 55 g on the x-frames, and 70 g on the y-frames. The u- and v-frames will have 641 wires, with the field wires at 400 g, and the sense wires at 55 g. DC5 will also have an updated front end electronics setup, using a new pre-amplifier-discriminator chip, in order to allow the recording of more events per second. The COMPASS project is a fixed-target nuclear physics experiment at CERN which explores the internal structure of the proton, and COMPASS ll's polarized Drell-Yan experiments will be exploring the quark angular momentum contribution to the spin of the proton through Semi-Inclusive Deep Inelastic Scattering. As a part of this process, Drift Chamber 5 (DC5), based on DC4 built by CEA-Saclay, must be constructed to replace a faulty straw chamber. The 23 total frames

  8. Supervised Self-Organizing Classification of Superresolution ISAR Images: An Anechoic Chamber Experiment

    NASA Astrophysics Data System (ADS)

    Radoi, Emanuel; Quinquis, André; Totir, Felix

    2006-12-01

    The problem of the automatic classification of superresolution ISAR images is addressed in the paper. We describe an anechoic chamber experiment involving ten-scale-reduced aircraft models. The radar images of these targets are reconstructed using MUSIC-2D (multiple signal classification) method coupled with two additional processing steps: phase unwrapping and symmetry enhancement. A feature vector is then proposed including Fourier descriptors and moment invariants, which are calculated from the target shape and the scattering center distribution extracted from each reconstructed image. The classification is finally performed by a new self-organizing neural network called SART (supervised ART), which is compared to two standard classifiers, MLP (multilayer perceptron) and fuzzy KNN ([InlineEquation not available: see fulltext.] nearest neighbors). While the classification accuracy is similar, SART is shown to outperform the two other classifiers in terms of training speed and classification speed, especially for large databases. It is also easier to use since it does not require any input parameter related to its structure.

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

    NASA Astrophysics Data System (ADS)

    Schnaiter, M.; Järvinen, E.; Vochezer, P.; Abdelmonem, A.; Wagner, R.; Jourdan, O.; Mioche, G.; Shcherbakov, V. N.; Schmitt, C. G.; Tricoli, U.; Ulanowski, Z.; Heymsfield, A. J.

    2015-11-01

    This study reports on the origin of ice crystal complexity and its influence on the angular light scattering properties of cirrus clouds. Cloud simulation experiments were conducted at the AIDA (Aerosol Interactions and Dynamics in the Atmosphere) cloud chamber of the Karlsruhe Institute of Technology (KIT). A new experimental procedure was applied to grow and sublimate ice particles at defined super- and subsaturated ice conditions and for temperatures in the -40 to -60 °C range. The experiments were performed for ice clouds generated via homogeneous and heterogeneous initial nucleation. Ice crystal complexity was deduced from measurements of spatially resolved single particle light scattering patterns by the latest version of the Small Ice Detector (SID-3). It was found that a high ice crystal complexity is dominating the microphysics of the simulated clouds and the degree of this complexity is dependent on the available water vapour during the crystal growth. Indications were found that the crystal complexity is influenced by unfrozen H2SO4/H2O residuals in the case of homogeneous initial ice nucleation. Angular light scattering functions of the simulated ice clouds were measured by the two currently available airborne polar nephelometers; the Polar Nephelometer (PN) probe of LaMP and the Particle Habit Imaging and Polar Scattering (PHIPS-HALO) probe of KIT. The measured scattering functions are featureless and flat in the side- and backward scattering directions resulting in low asymmetry parameters g around 0.78. It was found that these functions have a rather low sensitivity to the crystal complexity for ice clouds that were grown under typical atmospheric conditions. These results have implications for the microphysical properties of cirrus clouds and for the radiative transfer through these clouds.

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

    NASA Astrophysics Data System (ADS)

    Schnaiter, Martin; Järvinen, Emma; Vochezer, Paul; Abdelmonem, Ahmed; Wagner, Robert; Jourdan, Olivier; Mioche, Guillaume; Shcherbakov, Valery N.; Schmitt, Carl G.; Tricoli, Ugo; Ulanowski, Zbigniew; Heymsfield, Andrew J.

    2016-04-01

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

  11. Studies with cathode drift chambers for the GlueX experiment at Jefferson Lab

    DOE PAGES

    Pentchev, L.; Barbosa, F.; Berdnikov, V.; ...

    2017-04-22

    A drift chamber system consisting of 24 1 m-diameter chambers with both cathode and wire readout (total of 12,672 channels) is operational in Hall D at Jefferson Lab (Virginia). Two cathode strip planes and one wire plane in each chamber register the same avalanche allowing the study of avalanche development, charge induction process, and strip resolution. We demonstrate a method for reconstructing the two-dimensional distribution of the avalanche “center-of-gravity” position around the wire from an 55Fe source with resolutions down to 30 μm. We estimate the azimuthal extent of the avalanche around the wire as a function of the totalmore » charge for an Ar/CO2 gas mixture. By means of cluster counting using a modified 3 cm-gap chamber, we observe significant space charge effects within the same track, resulting in an extent of the avalanche along the wire.« less

  12. Studies with cathode drift chambers for the GlueX experiment at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Pentchev, L.; Barbosa, F.; Berdnikov, V.; Butler, D.; Furletov, S.; Robison, L.; Zihlmann, B.

    2017-02-01

    A drift chamber system consisting of 24 1 m-diameter chambers with both cathode and wire readout (total of 12,672 channels) is operational in Hall D at Jefferson Lab (Virginia). Two cathode strip planes and one wire plane in each chamber register the same avalanche allowing the study of avalanche development, charge induction process, and strip resolution. We demonstrate a method for reconstructing the two-dimensional distribution of the avalanche ;center-of-gravity; position around the wire from an 55Fe source with resolutions down to 30 μm. We estimate the azimuthal extent of the avalanche around the wire as a function of the total charge for an Ar/CO2 gas mixture. By means of cluster counting using a modified 3 cm-gap chamber, we observe significant space charge effects within the same track, resulting in an extent of the avalanche along the wire.

  13. Investigation of particle and vapor wall-loss effects on controlled wood-smoke smog-chamber experiments

    NASA Astrophysics Data System (ADS)

    Bian, Q.; May, A. A.; Kreidenweis, S. M.; Pierce, J. R.

    2015-06-01

    Smog chambers are extensively used to study processes that drive gas and particle evolution in the atmosphere. A limitation of these experiments is that particles and gas-phase species may be lost to chamber walls on shorter timescales than the timescales of the atmospheric processes being studied in the chamber experiments. These particle and vapor wall losses have been investigated in recent studies of secondary organic aerosol (SOA) formation, but they have not been systematically investigated in experiments of primary emissions from combustion. The semi-volatile nature of combustion emissions (e.g. from wood smoke) may complicate the behavior of particle and vapor wall deposition in the chamber over the course of the experiments due to the competition between gas/particle and gas/wall partitioning. Losses of vapors to the walls may impact particle evaporation in these experiments, and potential precursors for SOA formation from combustion may be lost to the walls, causing underestimates of aerosol yields. Here, we conduct simulations to determine how particle and gas-phase wall losses contributed to the observed evolution of the aerosol during experiments in the third Fire Lab At Missoula Experiment (FLAME III). We use the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm coupled with the organic volatility basis set (VBS) and wall-loss formulations to examine the predicted extent of particle and vapor wall losses. We limit the scope of our study to the dark periods in the chamber before photo-oxidation to simplify the aerosol system for this initial study. Our model simulations suggest that over one third of the initial particle-phase organic mass (36%) was lost during the experiments, and roughly half of this particle organic mass loss was from direct particle wall loss (56% of the loss) with the remainder from evaporation of the particles driven by vapor losses to the walls (44% of the loss). We perform a series of sensitivity tests to understand

  14. Investigation of particle and vapor wall-loss effects on controlled wood-smoke smog-chamber experiments

    NASA Astrophysics Data System (ADS)

    Bian, Q.; May, A. A.; Kreidenweis, S. M.; Pierce, J. R.

    2015-10-01

    Smog chambers are extensively used to study processes that drive gas and particle evolution in the atmosphere. A limitation of these experiments is that particles and gas-phase species may be lost to chamber walls on shorter timescales than the timescales of the atmospheric processes being studied in the chamber experiments. These particle and vapor wall losses have been investigated in recent studies of secondary organic aerosol (SOA) formation, but they have not been systematically investigated in experiments of primary emissions from combustion. The semi-volatile nature of combustion emissions (e.g. from wood smoke) may complicate the behavior of particle and vapor wall deposition in the chamber over the course of the experiments due to the competition between gas/particle and gas/wall partitioning. Losses of vapors to the walls may impact particle evaporation in these experiments, and potential precursors for SOA formation from combustion may be lost to the walls, causing underestimations of aerosol yields. Here, we conduct simulations to determine how particle and gas-phase wall losses contributed to the observed evolution of the aerosol during experiments in the third Fire Lab At Missoula Experiment (FLAME III). We use the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm coupled with the organic volatility basis set (VBS) and wall-loss formulations to examine the predicted extent of particle and vapor wall losses. We limit the scope of our study to the dark periods in the chamber before photo-oxidation to simplify the aerosol system for this initial study. Our model simulations suggest that over one-third of the initial particle-phase organic mass (41 %) was lost during the experiments, and over half of this particle-organic mass loss was from direct particle wall loss (65 % of the loss) with the remainder from evaporation of the particles driven by vapor losses to the walls (35 % of the loss). We perform a series of sensitivity tests to understand

  15. WE-G-BRA-06: Calibrating an Ionisation Chamber: Gaining Experience Using a Dosimetry 'flight Simulator'.

    PubMed

    Beavis, A; Saunderson, J; Ward, J

    2012-06-01

    Recently there has been great interest in the use of simulation training, with the view to enhance safety within radiotherapy practice. We have developed a Virtual Environment for Radiotherapy Training (VERT) which facilitates this, including the simulation of a number of 'Physics practices'. One such process is the calibration of an ionisation chamber for use in Linac photon beams. The VERT system was used to provide a life sized 3D virtual environment within which we were able to simulate the calibration of a departmental chamber for 6MV and 15 MV beams following the UK 1990 Code of Practice. The characteristics of the beams are fixed parameters in the simulation, whereas default (Absorbed dose to water) correction factors of the chambers are configurable thereby dictating their response in the virtual x-ray beam. When the simulation is started, a random, realistic temperature and pressure is assigned to the bunker. Measurement and chamber positional errors are assigned to the chambers. A virtual water phantom was placed on the Linac couch and irradiated through the side using a 10 × 10 field. With a chamber at the appropriate depths and irradiated iso-centrically, the Quality Indices (QI) of the beams were obtained. The two chambers were 'inter-compared', allowing the departmental chamber calibration factor to be calculated from that of the reference chamber. For the virtual 6/15 MV beams, the QI were found to be 0.668/ 0.761 and the inter-comparison ratios 0.4408/ 0.4402 respectively. The departmental chamber calibration factors were calculated; applying these and appropriate environmental corrections allowed the output of the Linac to be confirmed. We have shown how a virtual training environment can be used to demonstrate practical processes and reinforce learning. The UK CoP was used here, however any relevant protocol could be demonstrated. Two of the authors (Beavis and Ward) are Founders of Vertual Ltd, a spin-out company created to commercialise the

  16. Preliminary results of Resistive Plate Chambers operated with eco-friendly gas mixtures for application in the CMS experiment

    NASA Astrophysics Data System (ADS)

    Abbrescia, M.; Van Auwegem, P.; Benussi, L.; Bianco, S.; Cauwenbergh, S.; Ferrini, M.; Muhammad, S.; Passamonti, L.; Pierluigi, D.; Piccolo, D.; Primavera, F.; Russo, A.; Saviano, G.; Tytgat, M.

    2016-09-01

    The operations of Resistive Plate Chambers in LHC experiments require Fluorine based (F-based) gases for optimal performance. Recent European regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. In view of the CMS experiment upgrade, several tests are ongoing to measure the performance of the detector with these new ecological gas mixtures, in terms of efficiency, streamer probability, induced charge and time resolution. Prototype chambers with readout pads and with the standard CMS electronic setup are under test. In this paper preliminary results on performance of RPCs operated with a potential eco-friendly gas candidate 1,3,3,3-Tetrafluoropropene, commercially known as HFO-1234ze, with CO2 and CF3I based gas mixtures are presented and discussed for the possible application in the CMS experiment.

  17. The FLAME Deluge: organic aerosol emission ratios from combustion chamber experiments

    NASA Astrophysics Data System (ADS)

    Jolleys, Matthew; Coe, Hugh; McFiggans, Gordon; McMeeking, Gavin; Lee, Taehyoung; Sullivan, Amy; Kreidenweis, Sonia; Collett, Jeff

    2014-05-01

    A high level of variability has been identified amongst organic aerosol (OA) emission ratios (ER) from biomass burning (BB) under ambient conditions. However, it is difficult to assess the influences of potential drivers for this variability, given the wide range of conditions associated with wildfire measurements. Chamber experiments performed under controlled conditions provide a means of examining the effects of different fuel types and combustion conditions on OA emissions from biomass fuels. ERs have been characterised for 67 burns during the second Fire Laboratory at Missoula Experiment (FLAME II), involving 19 different species from 6 fuel types widely consumed in BB events in the US each year. Average normalised dOA/dCO ratios show a high degree of variability, both between and within different fuel types and species, typically exceeding variability between separate plumes in ambient measurements. Relationships with source conditions were found to be complex, with little consistent influence from fuel properties and combustion conditions for the entire range of experiments. No strong correlation across all fires was observed between dOA/dCO and modified combustion efficiency (MCE), which is used as an indicator of the proportional contributions of flaming and smouldering combustion phases throughout each burn. However, a negative correlation exists between dOA/dCO and MCE for some coniferous species, most notably Douglas fir, for which there is also an apparent influence from fuel moisture content. Significant contrasts were also identified between combustion emissions from different fuel components of additional coniferous species. Changes in fire efficiency were also shown to dramatically alter emissions for fires with very similar initial conditions. Although the relationship with MCE is variable between species, there is greater consistency with the level of oxygenation in OA. The ratio of the m/z 44 fragment to total OA mass concentration (f44) as

  18. Scintillation counter and wire chamber front end modules for high energy physics experiments

    SciTech Connect

    Baldin, Boris; DalMonte, Lou; /Fermilab

    2011-01-01

    This document describes two front-end modules developed for the proposed MIPP upgrade (P-960) experiment at Fermilab. The scintillation counter module was developed for the Plastic Ball detector time and charge measurements. The module has eight LEMO 00 input connectors terminated with 50 ohms and accepts negative photomultiplier signals in the range 0.25...1000 pC with the maximum input voltage of 4.0 V. Each input has a passive splitter with integration and differentiation times of {approx}20 ns. The integrated portion of the signal is digitized at 26.55 MHz by Analog Devices AD9229 12-bit pipelined 4-channel ADC. The differentiated signal is discriminated for time measurement and sent to one of the four TMC304 inputs. The 4-channel TMC304 chip allows high precision time measurement of rising and falling edges with {approx}100 ps resolution and has internal digital pipeline. The ADC data is also pipelined which allows deadtime-less operation with trigger decision times of {approx}4 {micro}s. The wire chamber module was developed for MIPP EMCal detector charge measurements. The 32-channel digitizer accepts differential analog signals from four 8-channel integrating wire amplifiers. The connection between wire amplifier and digitizer is provided via 26-wire twist-n-flat cable. The wire amplifier integrates input wire current and has sensitivity of 275 mV/pC and the noise level of {approx}0.013 pC. The digitizer uses the same 12-bit AD9229 ADC chip as the scintillator counter module. The wire amplifier has a built-in test pulser with a mask register to provide testing of the individual channels. Both modules are implemented as a 6Ux220 mm VME size board with 48-pin power connector. A custom europack (VME) 21-slot crate is developed for housing these front-end modules.

  19. Cooling Properties of the Shuttle Advanced Crew Escape Spacesuit: Results of an Environmental Chamber Experiment

    NASA Technical Reports Server (NTRS)

    Hamilton, Douglas; Gillis, David; Bue, Grant; Son, Chan; Norcross, Jason; Kuznetz, Larry; Chapman, Kirt; Chhipwadia, Ketan; McBride, Tim

    2008-01-01

    The shuttle crew wears the Advanced Crew Escape Spacesuit (ACES) to protect themselves from cabin decompression and to support bail out during landing. ACES is cooled by a liquid-cooled garment (LCG) that interfaces to a heat exchanger that dumps heat into the cabin. The ACES outer layer is made of Gore-Tex(Registered TradeMark), permitting water vapor to escape while containing oxygen. The crew can only lose heat via insensible water losses and the LCG. Under nominal landing operations, the average cabin temperature rarely exceeds 75 F, which is adequate for the ACES to function. Problem A rescue shuttle will need to return 11 crew members if the previous mission suffers a thermal protection system failure, preventing it from returning safely to Earth. Initial analysis revealed that 11 crew members in the shuttle will increase cabin temperature at wheel stop above 80 F, which decreases the ACES ability to keep crew members cool. Air flow in the middeck of the shuttle is inhomogeneous and some ACES may experience much higher temperatures that could cause excessive thermal stress to crew members. Methods A ground study was conducted to measure the cooling efficiency of the ACES at 75 F, 85 F, and 95 F at 50% relative humidity. Test subjects representing 5, 50, and 95 percentile body habitus of the astronaut corps performed hand ergometry keeping their metabolic rate at 400, 600, and 800 BTU/hr for one hour. Core temperature was measured by rectal probe and skin, while inside and outside the suit. Environmental chamber wall and cooling unit inlet and outlet temperatures were measured using high-resolution thermistors ( 0.2 C). Conclusions Under these test conditions, the ACES was able to protect the core temperature of all test subjects, however thermal stress due to high insensible losses and skin temperature and skin heat flow may impact crew performance. Further research should be performed to understand the impact on cognitive performance.

  20. Cooling Properties of the Shuttle Advanced Crew Escape Spacesuit: Results of an Environmental Chamber Experiment

    NASA Technical Reports Server (NTRS)

    Hamilton, Douglas; Gillis, David; Bue, Grant; Son, Chan; Norcross, Jason; Kuznetz, Larry; Chapman, Kirt; Chhipwadia, Ketan; McBride, Tim

    2008-01-01

    The shuttle crew wears the Advanced Crew Escape Spacesuit (ACES) to protect themselves from cabin decompression and to support bail out during landing. ACES is cooled by a liquid-cooled garment (LCG) that interfaces to a heat exchanger that dumps heat into the cabin. The ACES outer layer is made of Gore-Tex(Registered TradeMark), permitting water vapor to escape while containing oxygen. The crew can only lose heat via insensible water losses and the LCG. Under nominal landing operations, the average cabin temperature rarely exceeds 75 F, which is adequate for the ACES to function. Problem A rescue shuttle will need to return 11 crew members if the previous mission suffers a thermal protection system failure, preventing it from returning safely to Earth. Initial analysis revealed that 11 crew members in the shuttle will increase cabin temperature at wheel stop above 80 F, which decreases the ACES ability to keep crew members cool. Air flow in the middeck of the shuttle is inhomogeneous and some ACES may experience much higher temperatures that could cause excessive thermal stress to crew members. Methods A ground study was conducted to measure the cooling efficiency of the ACES at 75 F, 85 F, and 95 F at 50% relative humidity. Test subjects representing 5, 50, and 95 percentile body habitus of the astronaut corps performed hand ergometry keeping their metabolic rate at 400, 600, and 800 BTU/hr for one hour. Core temperature was measured by rectal probe and skin, while inside and outside the suit. Environmental chamber wall and cooling unit inlet and outlet temperatures were measured using high-resolution thermistors ( 0.2 C). Conclusions Under these test conditions, the ACES was able to protect the core temperature of all test subjects, however thermal stress due to high insensible losses and skin temperature and skin heat flow may impact crew performance. Further research should be performed to understand the impact on cognitive performance.

  1. Design and Applications of a Climatic Chamber for in-situ Neutron Imaging Experiments

    NASA Astrophysics Data System (ADS)

    Mannes, David; Schmid, Florian; Wehmann, Timon; Lehmann, Eberhard

    Due to the high sensitivity for hydrogen, the detection and quantification of moisture and moisture transport processes are some of the key topics in neutron imaging. Especially when dealing with hygroscopic material, such as wood and other porous media, it is crucial for quantitative analyses to know and control the ambient conditions of the sample precisely. In this work, a neutron transparent climatic chamber is presented, which was designed and built for the imaging facilities at the Paul Scherrer Institut (PSI), Villigen (CH). The air-conditioned measuring system consists of the actual sample chamber and a moisture generator providing air with adjustable temperature and relative humidity (%RH) (up to a dew point temperature of 70 °C). The two components are connected with a flexible tube, which features insulation, a heating system and temperature sensors to prevent condensation within the tube. The sample chamber itself is equipped with neutron transparent windows, insulating double walls with three feed-through openings for the rotation stage, sensors for humidity and temperature. Thermoelectric modules allow to control the chamber temperature in the range of -20 °C to 100 °C. The chamber allows to control the climatic conditions either in a static mode (stable temperature and %RH) or in dynamic mode (humidity or temperature cycles). The envisaged areas of application are neutron radiography and tomography investigations of dynamic processes in building materials (e.g. wood, concrete), food science and any other application necessitating the control of the climatic conditions.

  2. Flow chamber

    DOEpatents

    Morozov, Victor [Manassas, VA

    2011-01-18

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

  3. Utilizing Chamber Data for Developing and Validating Climate Change Models

    NASA Technical Reports Server (NTRS)

    Monje, Oscar

    2012-01-01

    Controlled environment chambers (e.g. growth chambers, SPAR chambers, or open-top chambers) are useful for measuring plant ecosystem responses to climatic variables and CO2 that affect plant water relations. However, data from chambers was found to overestimate responses of C fluxes to CO2 enrichment. Chamber data may be confounded by numerous artifacts (e.g. sidelighting, edge effects, increased temperature and VPD, etc) and this limits what can be measured accurately. Chambers can be used to measure canopy level energy balance under controlled conditions and plant transpiration responses to CO2 concentration can be elucidated. However, these measurements cannot be used directly in model development or validation. The response of stomatal conductance to CO2 will be the same as in the field, but the measured response must be recalculated in such a manner to account for differences in aerodynamic conductance, temperature and VPD between the chamber and the field.

  4. Note: A versatile mass spectrometer chamber for molecular beam and temperature programmed desorption experiments

    SciTech Connect

    Tonks, James P.; Galloway, Ewan C. King, Martin O.; Kerherve, Gwilherm; Watts, John F.

    2016-08-15

    A dual purpose mass spectrometer chamber capable of performing molecular beam scattering (MBS) and temperature programmed desorption (TPD) is detailed. Two simple features of this design allow it to perform these techniques. First, the diameter of entrance aperture to the mass spectrometer can be varied to maximize signal for TPD or to maximize angular resolution for MBS. Second, the mass spectrometer chamber can be radially translated so that it can be positioned close to the sample to maximize signal or far from the sample to maximize angular resolution. The performance of this system is described and compares well with systems designed for only one of these techniques.

  5. Note: A versatile mass spectrometer chamber for molecular beam and temperature programmed desorption experiments

    NASA Astrophysics Data System (ADS)

    Tonks, James P.; Galloway, Ewan C.; King, Martin O.; Kerherve, Gwilherm; Watts, John F.

    2016-08-01

    A dual purpose mass spectrometer chamber capable of performing molecular beam scattering (MBS) and temperature programmed desorption (TPD) is detailed. Two simple features of this design allow it to perform these techniques. First, the diameter of entrance aperture to the mass spectrometer can be varied to maximize signal for TPD or to maximize angular resolution for MBS. Second, the mass spectrometer chamber can be radially translated so that it can be positioned close to the sample to maximize signal or far from the sample to maximize angular resolution. The performance of this system is described and compares well with systems designed for only one of these techniques.

  6. Experiments with a pressure-driven Stirling refrigerator with flexible chambers

    NASA Astrophysics Data System (ADS)

    McFarlane, Patrick; Suire, Jonathan; Sen, Mihir; Semperlotti, Fabio

    2014-06-01

    We report on the design and experimental testing of a Stirling refrigerator that uses air as the working fluid, and where the conventional piston-cylinder assemblies are replaced by pressure-driven flexible chambers. The two chambers are periodically compressed by pneumatic actuators resulting in airflow through the regenerator and in a net temperature difference between the chambers. An experimental setup is used to investigate the performance of the refrigerator under different operating conditions with particular attention to actuation frequencies, driving pressure differences, and phase angles between the two inputs. The time constant of the temperature difference between the two chambers is determined, and the temperature difference is measured as a function of the system parameters. The results of several tests conducted under different operating conditions show that the refrigerating effect is very robust and allows good performance even for modulated inputs. The frequency response is radically different from that of a traditional motion-driven device. This work suggests that mechanical to thermal energy conversion devices based on this principle can be successfully powered by human motion.

  7. Unusual interactions above 100 TeV: A review of cosmic ray experiments with emulsion chambers

    NASA Technical Reports Server (NTRS)

    Yodh, D. B.

    1977-01-01

    A method is given for analyzing the space correlated collection of jets (gamma ray families) with energies greater than 100 TeV in Pb or Fe absorber sampled by photosensitive layers in an emulsion chamber. Events analyzed indicate large multiplicities of particles in the primary hadron-air interaction, and a marked absence of neutral pions.

  8. Atmospheric photochemistry of aromatic hydrocarbons: Analysis of OH budgets during SAPHIR chamber experiments and evaluation of MCMv3.2

    NASA Astrophysics Data System (ADS)

    Nehr, S.; Bohn, B.; Brauers, T.; Dorn, H.; Fuchs, H.; Häseler, R.; Hofzumahaus, A.; Li, X.; Lu, K.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2012-12-01

    Aromatic hydrocarbons, almost exclusively originating from anthropogenic sources, comprise a significant fraction of volatile organic compounds observed in urban air. The photo-oxidation of aromatics results in the formation of secondary pollutants and impacts air quality in cities, industrialized areas, and districts of dense traffic. Up-to-date photochemical oxidation schemes of the Master Chemical Mechanism (MCMv3.2) exhibit moderate performance in simulating aromatic compound degradation observed during previous environmental chamber studies. To obtain a better understanding of aromatic photo-oxidation mechanisms, we performed experiments with a number of aromatic hydrocarbons in the outdoor atmosphere simulation chamber SAPHIR located in Jülich, Germany. These chamber studies were designed to derive OH turnover rates exclusively based on experimental data. Simultaneous measurements of NOx (= NO + NO2), HOx (= OH + HO2), and the total OH loss rate constant k(OH) facilitate a detailed analysis of the OH budgets during photo-oxidation experiments. The OH budget analysis was complemented by numerical model simulations using MCMv3.2. Despite MCM's tendency to overestimate k(OH) and to underpredict radical concentrations, the OH budgets are reasonably balanced for all investigated aromatics. However, the results leave some scope for OH producing pathways that are not considered in the current MCMv3.2. An improved reaction mechanism, derived from MCMv3.2 sensitivity studies, is presented. The model performance is basically improved by changes of the mechanistic representation of ring fragmentation channels.

  9. Forward Drift Chamber for the GlueX experiment at the 12 GeV CEBAF machine

    SciTech Connect

    Lubomir Pentchev, Benedikt Zihlmann

    2011-06-01

    The GlueX experiment will search for exotic mesons produced by 9 GeV linearly polarized photons from the upgraded CEBAF machine. It is critical to detect and measure the four-momenta of all the charged particles and photons resulting from the decays of the mesons. The solenoid-based detector system includes tracking detectors and calorimeters. The Forward Drift Chamber, FDC, consists of 24 circular planar drift chambers of 1m diameter. Additional cathode readout is required to achieve efficient pattern recognition. The detection of low energy photons by the electromagnetic calorimeters imposes constraints on the amount of material used in the FDC. The specific features of the detector and the readout electronics will be described. Results from the tests of the full scale prototype will be presented, as well.

  10. IFE Final Optics and Chamber Dynamics Modeling and Experiments Final Technical Report

    SciTech Connect

    F. Najmabadi; M. S. Tillack

    2006-01-11

    Our OFES-sponsored research on IFE technology originally focused on studies of grazing-incidence metal mirrors (GIMM's). After the addition of GIMM research to the High Average Power Laser (HAPL) program, our OFES-sponsored research evolved to include laser propagation studies, surface material evolution in IFE wetted-wall chambers, and magnetic intervention. In 2003, the OFES IFE Technology program was terminated. We continued to expend resources on a no-cost extension in order to complete student research projects in an orderly way and to help us explore new research directions. Those explorations led to funding in the field of extreme ultraviolet lithography, which shares many issues in common with inertial fusion chambers, and the field of radiative properties of laser-produced plasma.

  11. Development of a proportional scintillation x-ray imaging chamber for synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

    Suzuki, Masayo; Takahashi, Tan; Awaya, Yohko; Oura, Masaki; Yamamoto, Masaki; Uruga, Tomoya; Mizogawa, Tatsumi; Masuda, Kimiaki

    1995-02-01

    Proportional scintillation x-ray imaging chamber (PSXIC) is a new type of two-dimensional position-sensitive x-ray detector composed of a spherical drift chamber, a parallel plate avalanche counter, and an image-intensifier-associated charge coupled device camera. A prototype of PSXIC filled with xenon (97%)+triethylamine (3%) gaseous mixture has been stably operated under a high flux of x-ray irradiation. The spatial resolution the prototype can attain has been found better than 800 μm. The time-resolved imaging capability has also been examined by taking time-varying x-ray images of a test pattern with a time resolution of 1/30 s.

  12. Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

    NASA Astrophysics Data System (ADS)

    Yver Kwok, C. E.; Müller, D.; Caldow, C.; Lebègue, B.; Mønster, J. G.; Rella, C. W.; Scheutz, C.; Schmidt, M.; Ramonet, M.; Warneke, T.; Broquet, G.; Ciais, P.

    2015-07-01

    This study presents two methods for estimating methane emissions from a waste water treatment plant (WWTP) along with results from a measurement campaign at a WWTP in Valence, France. These methods, chamber measurements and tracer release, rely on Fourier transform infrared spectroscopy and cavity ring-down spectroscopy instruments. We show that the tracer release method is suitable for quantifying facility- and some process-scale emissions, while the chamber measurements provide insight into individual process emissions. Uncertainties for the two methods are described and discussed. Applying the methods to CH4 emissions of the WWTP, we confirm that the open basins are not a major source of CH4 on the WWTP (about 10 % of the total emissions), but that the pretreatment and sludge treatment are the main emitters. Overall, the waste water treatment plant is representative of an average French WWTP.

  13. Search for anomalous C-jets in Chacaltaya emulsion chamber experiment

    NASA Technical Reports Server (NTRS)

    Kumano, H.

    1985-01-01

    Anomalous C-jets were measured in Chacaltaya emulsion chamber No.17. Measurement of 150 C-jets nuclear interactions occured in the target layer in the chamber itself with total visible energy greater than 5 TeV was completed. they are recorded in area of 11 sq m, corresponding to 17.1 sq m year exposure. Among them, seven events have no pinaught and two events are peculiar in that three showers out of four show abnormal cascade development. Two show remarkable characteristics indicating that they are coming from exotic interactions in the target layer. Illustrations of these events are presented and the thresholds of this type of event are discussed.

  14. NRL 324-cu m Chamber Pressurization Experiment: Pressurant Concentration Histories with and without Obstacles to Flow.

    DTIC Science & Technology

    1982-03-15

    consistent with the Corlett et al. scale-modeling hypothesis [2]. In this report, we describe the 324-m 3 chamber, its nitrogen pressure system, and...transient thermodynamic analysis by Corlett et al. (21. Reference 5 gives this analysis in more detail. In addition to pressurant concentrations at each...Halogenated Fire Extinguishing Agents, National Academy of Sciences, National Research Council, Washington, D.C., Apr. 1972, pp. 239-256. 2. R.C. Corlett

  15. Modeling SOA formation from alkanes and alkenes in chamber experiments: effect of gas/wall partitioning of organic vapors.

    NASA Astrophysics Data System (ADS)

    Stéphanie La, Yuyi; Camredon, Marie; Ziemann, Paul; Ouzebidour, Farida; Valorso, Richard; Madronich, Sasha; Lee-Taylor, Julia; Hodzic, Alma; Aumont, Bernard

    2014-05-01

    Oxidation products of Intermediate Volatility Organic Compounds (IVOC) are expected to be the major precursors of secondary organic aerosols (SOA). Laboratory experiments were conducted this last decade in the Riverside APRC chamber to study IVOC oxidative mechanisms and SOA formation processes for a large set of linear, branched and cyclic aliphatic hydrocarbons (Ziemann, 2011). This dataset are used here to assess the explicit oxidation model GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) (Aumont et al., 2005). The simulated SOA yields agree with the general trends observed in the chamber experiments. They are (i) increasing with the increasing carbon number; (ii) decreasing with increasing methyl branch number; and (iii) increasing for cyclic compounds compared to their corresponding linear analogues. However, simulated SOA yields are systematically overestimated regardless of the precursors, suggesting missing processes in the model. In this study, we assess whether gas-to-wall partitioning of organic vapors can explain these model/observation mismatches (Matsunaga and Ziemann, 2010). First results show that GECKO-A outputs better match the observations when wall uptake of organic vapors is taken into account. Effects of gas/wall partitioning on SOA yields and composition will be presented. Preliminary results suggest that wall uptake is a major process influencing SOA production in the Teflon chambers. References Aumont, B., Szopa, S., Madronich, S.: Modelling the evolution of organic carbon during its gas-phase tropospheric oxidation: development of an explicit model based on a self generating approach. Atmos.Chem.Phys., 5, 2497-2517 (2005). P. J. Ziemann: Effects of molecular structure on the chemistry of aerosol formation from the OH-radical-initiated oxidation of alkanes and alkenes, Int. Rev.Phys.Chem., 30:2, 161-195 (2011). Matsunaga, A., Ziemann, P. J.: Gas-wall partitioning of organic compounds in a Teflon film

  16. Bakeout Chamber Within Vacuum Chamber

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  17. Bakeout Chamber Within Vacuum Chamber

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  18. Determination of longevities, chamber building rates and growth functions for Operculina complanata from long term cultivation experiments

    NASA Astrophysics Data System (ADS)

    Woeger, Julia; Kinoshita, Shunichi; Wolfgang, Eder; Briguglio, Antonino; Hohenegger, Johann

    2016-04-01

    Operculina complanata was collected in 20 and 50 m depth around the Island of Sesoko belonging to Japans southernmost prefecture Okinawa in a series of monthly sampling over a period of 16 months (Apr.2014-July2015). A minimum of 8 specimens (4 among the smallest and 4 among the largest) per sampling were cultured in a long term experiment that was set up to approximate conditions in the field as closely as possible. A set up allowing recognition of individual specimens enabled consistent documentation of chamber formation, which in combination with μ-CT-scanning after the investigation period permitted the assignment of growth steps to specific time periods. These data were used to fit various mathematical models to describe growth (exponential-, logistic-, generalized logistic-, Gompertz-function) and chamber building rate (Michaelis-Menten-, Bertalanffy- function) of Operculina complanata. The mathematically retrieved maximum lifespan and mean chamber building rate found in cultured Operculina complanata were further compared to first results obtained by the simultaneously conducted "natural laboratory approach". Even though these comparisons hint at a somewhat stunted growth and truncated life spans of Operculina complanata in culture, they represent a possibility to assess and improve the quality of further cultivation set ups, opening new prospects to a better understanding of the their theoretical niches.

  19. Biochar application reduce ammonia volatilization in a soil-plant system: A closed chamber experiment

    NASA Astrophysics Data System (ADS)

    Mandal, Sanchita; Donner, Erica; Smith, Euan; Lombi, Enzo

    2017-04-01

    Ammonia (NH3) volatilization is considered as one of the major mechanisms responsible for the loss of nitrogen (N) from soil-plant systems worldwide. About 10-30% of N can be lost as NH3 volatilization, which constitutes a significant economic loss. In recent years carbon-based materials such as biochar have created a great research interest because of their ability to increase soil fertility by reducing nutrient loss and pollutants bioavailability in soil. Most of the studies so far have investigated how biochar addition can reduce NH3 volatilization from soils but less information is available for soil-plant systems. In this research, wheat plants (Triticum aestivum, variety: Calingiri) were grown in a calcareous soil (pH 8, calcarosol) inside a closed chamber system to assess both ammonia volatilization and plant N uptake. In this specialized glass chamber air was passed through an inlet where the flow rate was maintained using an air pump (3.5 L min-1). The air outlet was passed through a sulphuric acid trap which was used to capture the volatilized NH3 from the chamber. Plants were watered using the inlet to maintain 50% field capacity throughout the incubation. Two different biochar samples were used in this study: a poultry manure biochar (PM-BC) and a green waste compost biochar (GW-BC) produced at 250 ˚C. Five different application rates were tested (0, 0.5, 1, 1.5, and 2%). The soil was mixed with biochar samples, water, N, P, K, Ca, Mg, and S for one week before sowing. After one week of germination, plants were transferred to the chamber for further three weeks incubation for NH3 volatilization measurement. The study identified that biochar application reduced the NH3 volatilization and increase the plant biomass. Biochar application at 0.5 and 2% decreased the NH3 volatilization by 36 and 48% respectively. The N uptake of the plants also increased from 2.9 to 28% at 0.5 and 2% application rates respectively. The dry biomass of the plant also increased

  20. The design and mass production on Resistive Plate Chambers for the BESIII experiment

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawen; Chen, Jin; Han, Jifeng; Li, Rubai; Liu, Qian; Su, Minfa; Wang, Wanxiang; Wang, Yifang; Xie, Yuguang; Yao, Ning; Zhao, Haiquan; Zhao, Jianbing; Zhao, Jianzhong

    2007-10-01

    A new type of the phenolic paper laminate is used as the resistive electrodes of BESIII RPC. The surface smoothness of these laminates is comparable to that of the bakelite plates with linseed oil treating. A technique to adjust the bulk resistivity of the laminates within the range of 10 9-10 13 Ω cm is developed. Nowadays, about 1000 bare chambers (1200 m 2) have been produced and used for BESIII MUON, and the rejection rate is only 1.5%. In this paper, we will discuss the mass production and quality control procedures of these RPCs.

  1. BDPU, Helms places new test chamber into experiment module in LMS-1 Spacelab

    NASA Image and Video Library

    1996-07-09

    STS078-306-035 (20 June - 7 July 1996) --- Astronaut Susan J. Helms, payload commander, and payload specialist Jean-Jacques Favier, representing the French Space Agency (CNES), insert a test container into the Bubble Drop Particle Unit (BDPU) in the Life and Microgravity Spacelab (LMS-1) Science Module aboard the Space Shuttle Columbia. The fluid in the chamber is heated and the fluid processes are observed by use of three internal cameras mounted inside the BDPU. Investigations in this facility will help characterize interfacial processes involving either bubbles, drops, liquid columns or liquid layers.

  2. ARADISH - Development of a Standardized Plant Growth Chamber for Experiments in Gravitational Biology Using Ground Based Facilities

    NASA Astrophysics Data System (ADS)

    Schüler, Oliver; Krause, Lars; Görög, Mark; Hauslage, Jens; Kesseler, Leona; Böhmer, Maik; Hemmersbach, Ruth

    2016-06-01

    Plant development strongly relies on environmental conditions. Growth of plants in Biological Life Support Systems (BLSS), which are a necessity to allow human survival during long-term space exploration missions, poses a particular problem for plant growth, as in addition to the traditional environmental factors, microgravity (or reduced gravity such as on Moon or Mars) and limited gas exchange hamper plant growth. Studying the effects of reduced gravity on plants requires real or simulated microgravity experiments under highly standardized conditions, in order to avoid the influence of other environmental factors. Analysis of a large number of biological replicates, which is necessary for the detection of subtle phenotypical differences, can so far only be achieved in Ground Based Facilities (GBF). Besides different experimental conditions, the usage of a variety of different plant growth chambers was a major factor that led to a lack of reproducibility and comparability in previous studies. We have developed a flexible and customizable plant growth chamber, called ARAbidopsis DISH (ARADISH), which allows plant growth from seed to seedling, being realized in a hydroponic system or on Agar. By developing a special holder, the ARADISH can be used for experiments with Arabidopsis thaliana or a plant with a similar habitus on common GBF hardware, including 2D clinostats and Random Positioning Machines (RPM). The ARADISH growth chamber has a controlled illumination system of red and blue light emitting diodes (LED), which allows the user to apply defined light conditions. As a proof of concept we tested a prototype in a proteomic experiment in which plants were exposed to simulated microgravity or a 90° stimulus. We optimized the design and performed viability tests after several days of growth in the hardware that underline the utility of ARADISH in microgravity research.

  3. A cylindrical drift chamber for radiative muon capture experiments at TRIUMF

    SciTech Connect

    Henderson, R.S.; Dawson, R.J.; Azuelos, G.; Robertson, B.C. ); Hasinoff, M.D.; Ahamad, S.; Gorringe, T.P. ); Serna-Angel, A.; Blecher, M.; Wright, D.H. )

    1990-06-01

    In the Standard Model, the weak interaction is purely V-A in character. However in semileptonic reactions the strong force induces additional couplings. Radiative muon capture (RMC), {mu}{sup {minus}}{ital Z} {r arrow} {nu}({ital Z}{minus}1){gamma}, is a process which is particularly sensitive to the induced pseudoscalar coupling constant, {ital g{sub p}}, which is still very poorly determined experimentally. Due to the extremely small branching ratio ({approximately} 6 {times} 10{sup {minus}8}), the elementary reaction {mu}{sup {minus}}{ital p} {r arrow} {nu}{ital n}{gamma} has never been measured. Effort to date has concentrated on nuclear RMC where the branching ratio is much larger, but the interpretation of these results is hindered by nuclear structure uncertainties. A measurement is being carried out at TRIUMF to determine the rate of RMC on hydrogen to a precision of 8% leading to a determination of {ital g{sub p}} with an error of 10%. The detection system is based on a large volume cylindrical drift chamber, in an axial magnetic field, acting as an e{sup +}e{sup {minus}} pair spectrometer with a solid angle of {approx equal} 2 {pi}. The design, construction and performance of the cylindrical drift chamber are discussed.

  4. Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

    NASA Astrophysics Data System (ADS)

    Yver-Kwok, C. E.; Müller, D.; Caldow, C.; Lebègue, B.; Mønster, J. G.; Rella, C. W.; Scheutz, C.; Schmidt, M.; Ramonet, M.; Warneke, T.; Broquet, G.; Ciais, P.

    2015-03-01

    This study presents two methods for estimating methane emissions from a waste water treatment plant (WWTP) along with results from a measurement campaign at a WWTP in Valence, France. These methods, chamber measurements and tracer release, rely on Fourier Transform Infrared (FTIR) spectroscopy and Cavity Ring Down Spectroscopy (CRDS) instruments. We show that the tracer release method is suitable to quantify facility- and some process-scale emissions, while the chamber measurements, provide insight into individual process emissions. Uncertainties for the two methods are described and discussed. Applying the methods to CH4 emissions of the WWTP, we confirm that the open basins are not a major source of CH4 on the WWTP (about 10% of the total emissions), but that the pretreatment and sludge treatment are the main emitters. Overall, the waste water treatment plant represents a small part (about 1.5%) of the methane emissions of the city of Valence and its surroundings, which is lower than the national inventories.

  5. A single Time-of-Flight tray based on multigap resistive plate chambers for the STAR experiment at RHIC

    NASA Astrophysics Data System (ADS)

    Bonner, B.; Chen, H.; Eppley, G.; Geurts, F.; Lamas-Valverde, J.; Li, Ch.; Llope, W. J.; Nussbaum, T.; Platner, E.; Roberts, J.

    2003-08-01

    The STAR experiment at RHIC plans to implement a 60 m2 Time-of-Flight (TOF) system. The Multigap Resistive Plate Chamber (MRPC) is a suitable candidate for the STAR TOF system due to its time resolution of order of 60 ps with efficiencies in excess of 97%. We obtained this result with modules composed of 6 gas gaps of 220 μm and pad area of 20 cm2. In this paper, we report on the performance of this MRPC module and present the current status of the construction and installation into STAR of a prototype tray.

  6. A chamber-experiment investigation of the interaction between perceptions of noise and odor in humans.

    PubMed

    Pan, Zhiwei; Kjaergaard, Søren K; Mølhave, Lars

    2003-10-01

    This study was designed to investigate human comfort and health effects following exposure to noise and odor and to explore the interaction between perceptions of noise and odor in humans. Nine healthy subjects were randomly exposed to noise, odor, and their combination, in a 3 x 3 Latin square design for 80 min in an exposure chamber. Continuous noise was broadcast at an average level of 75 dBA by a loudspeaker, and odor was provided by furfurylmercaptan (a coffee-aroma constituent). A standardized 28-item questionnaire, together with mood-scale ratings, nasal dimensions by acoustic rhinometry, addition tests for distraction, and skin humidity, were performed before and at the end of exposure. In the questionnaire investigation, the perceived "sound level" was significantly affected by noise and the combined exposures, while "odor intensity", "air quality", and "need more ventilation" was significantly affected by odor and the combined exposures. Perceptions of symptoms became worse with increasing exposure time, such as perceived "dry nose" and "sleepiness" by odor and combined exposures, "headache" by noise, "concentration difficulty", "general well being", and "stressed by being in the chamber" by noise, odor and combined exposures. In addition, the occurrence of interactions was analyzed by comparison of the ratings of perceived "sound level", "odor intensity", "air quality", and "need more ventilation" during the combined exposure with two single exposures. Insignificant interaction was found but it indicated a decreased tendency to perceptions of discomfort from "odor intensity", "air quality", and "need for more ventilation" when noise was added to odor exposure. It may be concluded that noise and odor cause discomfort in humans. Moreover, the study might indicate that additions of noise reduce (mask) the perception of discomfort from odor, and additions of odor have no or little affect on the perception of noise.

  7. Development of a Novel Contamination Resistant Ion Chamber for Process Tritium Measurement and Use in the JET First Trace Tritium Experiment

    SciTech Connect

    Worth, L.B.C.; Pearce, R.J.H.; Bruce, J.; Banks, J.; Scales, S.

    2005-07-15

    The accuracy of process measurements of tritium with conventional ion chambers is often affected by surface tritium contamination. The measurement of tritium in the exhaust of the JET torus is particularly difficult due to surface contamination with highly tritiated hydrocarbons. JET's first unsuccessful attempt to overcome the contamination problem was to use an ion chamber, with a heating element as the chamber wall so that it could be periodically decontaminated by baking. The newly developed ion chamber works on the principle of minimising the surface area within the boundary of the anode and cathode.This paper details the design of the ion chamber, which utilises a grid of 50-micron tungsten wire to define the ion chamber wall and the collector electrode. The effective surface area which, by contamination, is able to effect the measurement of tritium within the process gas has been reduced by a factor of {approx}200 over a conventional ion chamber. It is concluded that the new process ion chamber enables sensitive accurate tritium measurements free from contamination issues. It will be a powerful new tool for future tritium experiments both to improve tritium tracking and to help in the understanding of tritium retention issues.

  8. Smog chamber experiments to investigate Henry's law constants of glyoxal using different seed aerosols

    NASA Astrophysics Data System (ADS)

    Jakob, Ronit

    2014-05-01

    Aerosols play an important role in the chemistry and physics of the atmosphere. Hence, they have a direct as well as an indirect impact on the earth's climate. Depending on their formation, one distinguishes between primary and secondary aerosols[1]. Important groups within the secondary aerosols are the secondary organic aerosols (SOAs). In order to improve predictions about these impacts on the earth's climate the existing models need to be optimized, because they still underestimate SOA formation[2]. Glyoxal, the smallest α-dicarbonyl, not only acts as a tracer for SOA formation but also as a direct contributor to SOA. Because glyoxal has such a high vapour pressure, it was common knowledge that it does not take part in gas-particle partitioning and therefore has no impact on direct SOA formation. However, the Henry's law constant for glyoxal is surprisingly high. This has been explained by the hydration of the aldehyde groups, which means that a species with a lower vapour pressure is produced. Therefore the distribution of glyoxal between gas- and particle phase is atmospherically relevant and the direct contribution of glyoxal to SOA can no longer be neglected. A high salt concentration present in chamber seed aerosols leads to an enhanced glyoxal uptake into the particle. This effect is called "salting-in". The salting effect depends on the composition of the seed aerosol as well as the soluble compound. For very polar compounds, like glyoxal, a "salting-in" is observed[3]. Glyoxal particle formation during a smog chamber campaign at Paul-Scherrer-Institut (PSI) in Switzerland was examined using different seed aerosols such as ammonium sulfate, sodium chloride and sodium nitrate. The aim of this campaign was to investigate Henry's law constants for different seed aerosols. During the campaign filter samples were taken to investigate the amount of glyoxal in the particle phase. After filter extraction, the analyte was derivatized and measured using UHPLC

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather, and general circulation models. The detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud particle-size range below 50 μm, remains challenging in mixed phase, often unstable environments. The Cloud Aerosol Spectrometer with Polarization (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure the variability in polarization state of their backscattered light. Here we operate the versatile Cosmics Leaving OUtdoor Droplets (CLOUD) chamber facility at the European Organization for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water, and ice particles. In this paper, optical property measurements of mixed-phase clouds and viscous secondary organic aerosol (SOA) are presented. We report observations of significant liquid-viscous SOA particle polarization transitions under dry conditions using CASPOL. Cluster analysis techniques were subsequently used to classify different types of particles according to their polarization ratios during phase transition. A classification map is presented for water droplets, organic aerosol (e.g., SOA and oxalic acid), crystalline substances such as ammonium sulfate, and volcanic ash. Finally, we discuss the benefits and limitations of this classification approach for atmospherically relevant concentrations and mixtures with respect to the CLOUD 8-9 campaigns and its potential contribution to tropical troposphere layer analysis.

  10. Investigation, comparison and design of chambers used in centrifugal partition chromatography on the basis of flow pattern and separation experiments.

    PubMed

    Schwienheer, C; Merz, J; Schembecker, G

    2015-04-17

    In centrifugal partition chromatography (CPC) the separation efficiency is mainly influenced by the hydrodynamic of mobile and stationary phase in the chambers. Thus, the hydrodynamic has to be investigated and understood in order to enhance a CPC separation run. Different chamber geometries have been developed in the past and the influence of several phase systems and CPC operating conditions were investigated for these chambers. However, a direct comparison between the different chamber types has not been performed yet. In order to investigate the direct influence of the chamber design on the hydrodynamic, several chamber designs - partially similar in geometry to commercial available designs - are investigated under standardized conditions in the present study. The results show the influence of geometrical aspects of the chamber design on the hydrodynamic and therewith, on the separation efficiency. As a conclusion of the present study, some ideas for an optimal chamber design for laboratory and industrial purpose are proposed.

  11. Direct Observation of Secondary Organic Aerosol Formation during Cloud Condensation-Evaporation Cycles (SOAaq) in Simulation Chamber Experiments

    NASA Astrophysics Data System (ADS)

    Doussin, J. F.; Bregonzio-Rozier, L.; Giorio, C.; Siekmann, F.; Gratien, A.; Temime-Roussel, B.; Ravier, S.; Pangui, E.; Tapparo, A.; Kalberer, M.; Monod, A.

    2014-12-01

    Biogenic volatile organic compounds (BVOCs) undergo many reactions in the atmosphere and form a wide range of oxidised and water-soluble compounds. These compounds can partition into atmospheric water droplets, and react within the aqueous phase producing higher molecular weight and/or less volatile compounds which can remain in the particle phase after water evaporation and thus increase the organic aerosol mass (Ervens et al., 2011; Altieri et al., 2008; Couvidat et al., 2013). While this hypothesis is frequently discussed in the literature, so far, almost no direct observations of such a process have been provided.The aim of the present work is to study SOA formation from isoprene photooxidation during cloud condensation-evaporation cycles.The experiments were performed during the CUMULUS project (CloUd MULtiphase chemistry of organic compoUndS in the troposphere), in the CESAM simulation chamber located at LISA. CESAM is a 4.2 m3 stainless steel chamber equipped with realistic irradiation sources and temperature and relative humidity (RH) controls (Wang et al., 2011). In each experiment, isoprene was allowed to oxidize during several hours in the presence on nitrogen oxides under dry conditions. Gas phase compounds were analyzed on-line by a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS), a Fourier Transform Infrared Spectrometer (FTIR), NOx and O3 analyzers. SOA formation was monitored on-line with a Scanning Mobility Particle Sizer (SMPS) and an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). The experimental protocol was optimised to generate cloud events in the simulation chamber, which allowed us to generate clouds lasting for ca. 10 minutes in the presence of light.In all experiments, we observed that during cloud formation, water-soluble gas-phase oxidation products (e.g., methylglyoxal, hydroxyacetone, acetaldehyde, formic acid, acetic acid and glycolaldehyde) readily partitioned into cloud

  12. Exposure chamber

    DOEpatents

    Moss, Owen R.; Briant, James K.

    1983-01-01

    An exposure chamber includes an imperforate casing having a fluid inlet at the top and an outlet at the bottom. A single vertical series of imperforate trays is provided. Each tray is spaced on all sides from the chamber walls. Baffles adjacent some of the trays restrict and direct the flow to give partial flow back and forth across the chambers and downward flow past the lowermost pan adjacent a central plane of the chamber.

  13. Choice chamber experiments to test the attraction of postflexion Rhabdosargus holubi larvae to water of estuarine and riverine origin

    NASA Astrophysics Data System (ADS)

    James, Nicola C.; Cowley, Paul D.; Whitfield, Alan K.; Kaiser, Horst

    2008-03-01

    Although the recruitment of larvae and juveniles of marine fishes into estuaries has been well documented, little is known about the factors governing the immigration of estuary-associated marine fishes into estuaries. Fishes have a well-developed sense of smell and it has been suggested by several workers that olfactory cues of freshwater or estuarine origin serve as stimuli, attracting larvae and juveniles of estuary-associated species into estuaries. Attraction of postflexion Rhabdosargus holubi larvae to estuary and river water from the Kowie estuarine system, South Africa, was measured using a rectangular choice chamber. In experiments, conducted during peak recruitment periods, larvae selected estuary and river water with a significantly higher frequency than sea water. This study, the first to assess the possible role of olfaction in the recruitment process of an estuary-associated marine fish species, demonstrates that larvae are able to recognise water from different origins, probably based on odour.

  14. On the halo events observed by Mount Fuji and Mount Kanbala Emulsion Chamber Experiments

    NASA Technical Reports Server (NTRS)

    Ren, J. R.; Kuang, H. H.; Huo, A. X.; Lu, S. L.; Su, S.; Wang, Y. X.; Xue, Y. G.; Wang, C. R.; He, M.; Zhang, N. J.

    1985-01-01

    The intensity of big gamma-ray families associated by halo is obtained from Mt. Fuji experiment (650 g/sq.cm. atmospheric depth) and Mt. Kanbala experiment (515 g/sq.cm.). The results are compared with Monte Carlo calculation based on several assumptions on interaction mechanisms and the primary cosmic ray composition. The results suggest more than 3 times lower proton abundance among primaries than that of 10 to the 12th to 10 to the 13th eV region within the framework of quasi-scaling model of multiple production.

  15. Validation of a δ2Hn-alkane-δ18Ohemicellulose based paleohygrometer: Implications from a climate chamber experiment

    NASA Astrophysics Data System (ADS)

    Hepp, Johannes; Kathrin Schäfer, Imke; Tuthorn, Mario; Wüthrich, Lorenz; Zech, Jana; Glaser, Bruno; Juchelka, Dieter; Rozanski, Kazimierz; Zech, Roland; Mayr, Christoph; Zech, Michael

    2017-04-01

    Leaf wax-derived biomarkers, e.g. long chain n-alkanes and fatty acids, and their hydrogen isotopic composition are proved to be of a value in paleoclimatology/-hydrology research. However, the alteration of the isotopic signal as a result of the often unknown amount of leaf water enrichment challenges a direct reconstruction of the isotopic composition of paleoprecipitation. The coupling of ^2H/^1H results of leaf wax-derived biomarkers with 18O/16O results of hemicellulose-derived sugars has the potential to overcome this limitation and additionally allows reconstructing relative air humidity (RH) (Zech et al., 2013). This approach was recently validated by Tuthorn et al. (2015) by applying it to topsoil samples along a climate transect in Argentina. Accordingly, the biomarker-derived RH values correlate significantly with modern actual RH values from the respective study sites, showing the potential of the established 'paleohygrometer' approach. However, a climate chamber validation study to answer open questions regarding this approach, e.g. how robust biosynthetic fractionation factors are, is still missing. Here we present coupled δ2Hn-alkane-δ18Ohemicellulose results obtained for leaf material from a climate chamber experiment, in which Eucalyptus globulus, Vicia faba and Brassica oleracea were grown under controlled conditions (Mayr, 2003). First, the 2H and 18O enrichment of leaf water strongly reflects actual RH values of the climate chambers. Second, the biomarker-based reconstructed RH values correlate well with the actual RH values of the respective climate chamber, validating the proposed 'paleohygrometer' approach. And third, the calculated fractionation factors between the investigated leaf biomarkers (n-C29 and n-C31 for alkanes; arabinose and xylose for hemicellulose) and leaf water are close to the expected once reviewed from the literature (+27\\permil for hemicellulose; -155\\permil for n-alkanes). Nevertheless, minor dependencies of these

  16. C{sub 5}{sup A} axial form factor from bubble chamber experiments

    SciTech Connect

    Graczyk, K. M.; Sobczyk, J. T.; Kielczewska, D.; Przewlocki, P.

    2009-11-01

    A careful reanalysis of both Argonne National Laboratory and Brookhaven National Laboratory data for weak single pion production is done. We consider deuteron nuclear effects and normalization (flux) uncertainties in both experiments. We demonstrate that these two sets of data are in good agreement. For the dipole parametrization of C{sub 5}{sup A}(Q{sup 2}), we obtain C{sub 5}{sup A}(0)=1.19{+-}0.08, M{sub A}=0.94{+-}0.03 GeV. As an application we present the discussion of the uncertainty of the neutral current 1{pi}{sup 0} production cross section, important for the T2K neutrino oscillation experiment.

  17. Chamber transport

    SciTech Connect

    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.

  18. Optimization of the Ussing chamber setup with excised rat intestinal segments for dissolution/permeation experiments of poorly soluble drugs.

    PubMed

    Forner, Kristin; Roos, Carl; Dahlgren, David; Kesisoglou, Filippos; Konerding, Moritz A; Mazur, Johanna; Lennernäs, Hans; Langguth, Peter

    2017-02-01

    Prediction of the in vivo absorption of poorly soluble drugs may require simultaneous dissolution/permeation experiments. In vivo predictive media have been modified for permeation experiments with Caco-2 cells, but not for excised rat intestinal segments. The present study aimed at improving the setup of dissolution/permeation experiments with excised rat intestinal segments by assessing suitable donor and receiver media. The regional compatibility of rat intestine in Ussing chambers with modified Fasted and Fed State Simulated Intestinal Fluids (Fa/FeSSIFmod) as donor media was evaluated via several parameters that reflect the viability of the excised intestinal segments. Receiver media that establish sink conditions were investigated for their foaming potential and toxicity. Dissolution/permeation experiments with the optimized conditions were then tested for two particle sizes of the BCS class II drug aprepitant. Fa/FeSSIFmod were toxic for excised rat ileal sheets but not duodenal sheets, the compatibility with jejunal segments depended on the bile salt concentration. A non-foaming receiver medium containing bovine serum albumin (BSA) and Antifoam B was nontoxic. With these conditions, the permeation of nanosized aprepitant was higher than of the unmilled drug formulations. The compatibility of Fa/FeSSIFmod depends on the excised intestinal region. The chosen conditions enable dissolution/permeation experiments with excised rat duodenal segments. The experiments correctly predicted the superior permeation of nanosized over unmilled aprepitant that is observed in vivo. The optimized setup uses FaSSIFmod as donor medium, excised rat duodenal sheets as permeation membrane and a receiver medium containing BSA and Antifoam B.

  19. The Accommodation Coefficient of Water Molecules on Ice: Results from Cirrus Cloud Experiments at the Aerosol Chamber AIDA

    NASA Astrophysics Data System (ADS)

    Skrotzki, J.; Connolly, P.; Niemand, M.; Saathoff, H.; Moehler, O.; Ebert, V.; Leisner, T.

    2010-12-01

    Cirrus clouds are pure ice clouds in the upper troposphere or lower stratosphere. One of the parameters governing the growth of ice crystals in these clouds is the accommodation coefficient of water molecules on ice. However, its magnitude is still uncertain to a large degree, since experimental results vary from below 0.01 up to unity depending on the design of the experiment and the examined ice growth process [1]. For the specific case of ice crystal growth in cirrus clouds, no previous experimental studies regarding the accommodation coefficient exist. Therefore, dedicated experiments were carried out at the cloud simulation chamber AIDA [2], examining the ice crystal growth for deposition nucleation in the temperature range from -75 °C to -40 °C. These experiments were evaluated with two different models, a simple one, which just incorporates kinetic and diffusive theory of ice crystal growth, and the more advanced and extended aerosol-cloud-precipitation interaction model (ACPIM) [3]. The outcome of these two models is compared to absolute in-situ humidity data measured within AIDA using extractive as well as open path diode laser hygrometers (TDLAS) [4]. For every experiment, this is done by varying the value of the accommodation coefficient within each model, in order to get best agreement with experimental data. The values obtained for the accommodation coefficient at different temperatures are presented and the overall uncertainties as well as the consistency between the two different models are discussed. [1] D. R. Heynes, N. J. Tro, and S. M. George, J. Phys. Chem. 1992, 96, 8502-8509 (1992) [2] O. Möhler et al., Atmos. Chem. Phys. 3, 211-223 (2003) [3] P. J. Connolly et al., Atmos. Chem. Phys. 9, 2805-2824 (2009) [4] D. W. Fahey et al., AquaVIT White Paper, avail. at https://aquavit.icg.kfa-juelich.de/AquaVit/AquaVitWiki

  20. Exposure chamber

    DOEpatents

    Moss, Owen R.

    1980-01-01

    A chamber for exposing animals, plants, or materials to air containing gases or aerosols is so constructed that catch pans for animal excrement, for example, serve to aid the uniform distribution of air throughout the chamber instead of constituting obstacles as has been the case in prior animal exposure chambers. The chamber comprises the usual imperforate top, bottom and side walls. Within the chamber, cages and their associated pans are arranged in two columns. The pans are spaced horizontally from the walls of the chamber in all directions. Corresponding pans of the two columns are also spaced horizontally from each other. Preferably the pans of one column are also spaced vertically from corresponding pans of the other column. Air is introduced into the top of the chamber and withdrawn from the bottom. The general flow of air is therefore vertical. The effect of the horizontal pans is based on the fact that a gas flowing past the edge of a flat plate that is perpendicular to the flow forms a wave on the upstream side of the plate. Air flows downwardly between the chamber walls and the outer edges of the pan. It also flows downwardly between the inner edges of the pans of the two columns. It has been found that when the air carries aerosol particles, these particles are substantially uniformly distributed throughout the chamber.

  1. Wire chamber

    DOEpatents

    Atac, Muzaffer

    1989-01-01

    A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

  2. Study of timing response and charge spectra of glass based Resistive Plate Chamber detectors for INO-ICAL experiment

    NASA Astrophysics Data System (ADS)

    Gaur, A.; Kumar, A.; Naimuddin, Md.

    2017-03-01

    Resistive Plate chambers (RPCs) are robust and affordable gaseous detectors that combine low cost with excellent timing, good spatial resolution and fast response to the incoming particles. The India Based Neutrino Observatory is an approved project aimed at building a magnetised Iron Calorimeter (ICAL) detector to study Neutrino physics and related issues. The ICAL experiment will utilize about 29000 RPC's as active detector elements, sandwiched between alternate plates of thick iron. The RPC detectors will be used to detect muons produced from the atmospheric neutrinos interaction with an iron target. The spatial information of the muons will be extracted from the two dimensional readout and the hit position in the respective layers. The up going and down going directionality will be obtained using the time stamp of hits in the active detectors. The charge induced by the particle and its behaviour with respect to the applied voltage play a significant role in designing the readout electronics for the detector. In this paper, we present the timing and charge measurement of single gap glass based RPC detectors. We will also report about studies on the dependence of the timing and charge response of these RPC detectors as a function of the gas composition.

  3. Paragenesis of Diamond and Minerals of Peridotites and Carbonatites in the Mantle Magma Chambers Based on Experiments Data

    NASA Astrophysics Data System (ADS)

    Kuzyura, Anastasia; Simonova, Dariya; Litvin, Yury

    2014-05-01

    It is considered that role of carbonate melts is important in processes of mantle metasomatism; according to other representations, it is also assumed that they could be formed at partial melting of carbonated peridotite. Dissolving of peridotite minerals and carbon in carbonate melts are responsible for formation of completely miscible carbonate-silicate-carbon magmas parental for diamonds. It can be expected that such carbonate magmas are capable to assimilate an form parental magama "chambers" within the hosting mantle peridotite. While natural cooling of the chambers dissolved in carbonate melts components of the peridotite crystallize forming minerals similar to these of the host mantle peridotite. The recrystallized peridotite minerals are fragmentarily included hermetically within growing diamonds and occur as syngenetic inclusions in them. Therefore experimental modeling of origin of the upper mantle carbonate-silicate diamond-forming melts, their consolidations in the magmatic chambers and evolutions at conditions of equilibrium and fractional crystallization are especially significant for understanding of processes of deep magmatic petrology and genetic mineralogy, including genesis of diamond. In the study at 6 GPa model approximations of mineral phases, significant in compositions of probable metasomatic agents, the upper mantle peridotites, and also syngenetic inclusions in diamonds were used: starting mixtures were model peridotite with composition Ol48Opx16Cpx16Grt20, close to model compositions of the primitive mantle and real mantle xenolithes, as well as multicomponent carbonate (CaCO3)20(Na2CO3)20(FeCO3)20(Na2CO3)20(K2CO3)20 modeling carbonatite inclusions in natural diamonds. Spectral pure graphite was used as a source of carbon in the system. Pressure and temperature were reached using apparatus of toroidal type 'anvil-with-hole'. Electron microprobe and SEM researches were carried out on the polished surfaces with carbon covering at IEM RAS

  4. [Proposal of a cloud chamber experiment using diagnostic X-ray apparatus and an analysis assisted by a simulation code].

    PubMed

    Hayashi, Hiroaki; Hanamitsu, Hiroki; Nishihara, Sadamitsu; Ueno, Junji; Miyoshi, Hirokazu

    2013-04-01

    A cloud chamber is a radiation detector that can visualize the tracks of charged particles. In this study, we developed a middle-type cloud chamber for use in practical training using a diagnostic X-ray apparatus. Because our cloud chamber has a heater to vaporize ethanol and features antifogging glass, it is possible to observe the vapor trails for a long time without the need for fine adjustments. X-rays with a tube voltage of 40 kV or of 120 kV (with a 21-mm aluminum filter) were irradiated at the chamber and the various phenomena were observed. We explain these phenomena in terms of the range of electrons and/or interactions between X-rays and matter and conclude that our analysis is consistent with analysis using the Monte Carlo simulation code EGS5.

  5. Super-family P2 C-96-125 observed by Japan-URSS Joint Emulsion Chamber Experiment

    NASA Technical Reports Server (NTRS)

    Shibuya, E. H.

    1985-01-01

    A detailed description of the event detected in the second chamber of Japan-URSS Collaboration is presented. A preliminary description was already published and from that time a careful microscopic scanning was carried out.

  6. Super-family P2 C-96-125 observed by Japan-URSS Joint Emulsion Chamber Experiment

    NASA Astrophysics Data System (ADS)

    Shibuya, E. H.

    1985-08-01

    A detailed description of the event detected in the second chamber of Japan-URSS Collaboration is presented. A preliminary description was already published and from that time a careful microscopic scanning was carried out.

  7. Bromine Explosions In Smog Chamber Experiments: A comparison of Cavity-Enhanced (CE) and White-cell DOAS

    NASA Astrophysics Data System (ADS)

    Buxmann, J.; Hoch, D. J.; Sihler, H.; Pöhler, D.; Platt, U.; Bleicher, S.; Balzer, N.; Zetzsch, C.

    2011-12-01

    Reactive halogen species (RHS), such as Cl, Br or BrO, can significantly influence chemical processes in the troposphere, including the destruction of ozone, change in the chemical balance of hydrogen radicals (OH, HO2), increased deposition of toxic compounds (like mercury) with potential consequences for the global climate. Previous studies have shown that salt lakes can be significant sources for gaseous RHS. Environmental conditions such as salt composition, relative humidity (RH), pH, and temperature (T) can strongly influence reactive bromine levels, but are difficult to quantify in the field. Therefore, we conducted laboratory experiments by exposing NaCl salt containing 0.33% (by weight) NaBr to simulated sunlight in a Teflon smog-chamber under various conditions of RH and ozone concentrations. BrO levels were observed by a Differential-Optical-Absorption-Spectrometer (DOAS) in combination with a multi-reflection cell (White-cell). The concentrations of OH- and Cl- radicals were quantified by the radical clock method. We present the first direct observation of BrO from the "Bromine Explosion" (auto catalytic release of reactive bromine from salt surfaces - key to ozone destruction) in the laboratory above a simulated salt pan. The maximum BrO mixing ratio of 6419±71 ppt at 60% RH was observed to be one order of magnitude higher than at 37% RH and 2% RH. The release of RHS from the salt pan is possibly controlled by the thickness of the quasi liquid layer, covering the reactive surface of the halide crystals, as the layer thickness strongly depends on RH. Furthermore, a new cavity enhanced DOAS (CE-DOAS) instrument was designed and successfully used in chamber experiments. For the first time, such an instrument uses a spectral interval in the UV - wavelength range (325-365 nm) to identify BrO. We show a comparison of the CE-DOAS and White-cell DOAS instrument in a series of experiments, where e.g. a peak BrO mixing ratio up to 380 ppt within the first

  8. IONIZATION CHAMBER

    DOEpatents

    Redman, W.C.; Shonka, F.R.

    1958-02-18

    This patent describes a novel ionization chamber which is well suited to measuring the radioactivity of the various portions of a wire as the wire is moved at a uniform speed, in order to produce the neutron flux traverse pattern of a reactor in which the wire was previously exposed to neutron radiation. The ionization chamber of the present invention is characterized by the construction wherein the wire is passed through a tubular, straight electrode and radiation shielding material is disposed along the wire except at an intermediate, narrow area where the second electrode of the chamber is located.

  9. New cloud chamber experiments on the heterogeneous ice nucleation ability of oxalic acid in the immersion mode

    NASA Astrophysics Data System (ADS)

    Wagner, R.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Leisner, T.

    2011-03-01

    The heterogeneous ice nucleation ability of oxalic acid in the immersion mode has been investigated by controlled expansion cooling runs with airborne, ternary solution droplets composed of, (i), sodium chloride, oxalic acid, and water (NaCl/OA/H2O) and, (ii), sulphuric acid, oxalic acid, and water (H2SO4/OA/H2O). Polydisperse aerosol populations with median diameters ranging from 0.5-0.7 μm and varying solute concentrations were prepared. The expansion experiments were conducted in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at initial temperatures of 244 and 235 K. In the ternary NaCl/OA/H2O system, solid inclusions of oxalic acid, presumably nucleated as oxalic acid dihydrate, were formed by temporarily exposing the ternary solution droplets to a relative humidity below the efflorescence point of NaCl. The matrix of the crystallised NaCl particulates triggered the precipitation of the organic crystals which later remained as solid inclusions in the solution droplets when the relative humidity was subsequently raised above the deliquescence point of NaCl. The embedded oxalic acid crystals reduced the critical ice saturation ratio required for the homogeneous freezing of pure NaCl/H2O solution droplets at a temperature of around 231 K from 1.38 to about 1.32. Aqueous solution droplets with OA inclusions larger than about 0.27 μm in diameter efficiently nucleated ice by condensation freezing when they were activated to micron-sized cloud droplets at 241 K, i.e., they froze well above the homogeneous freezing temperature of pure water droplets of about 237 K. Our results on the immersion freezing potential of oxalic acid corroborate the findings from a recent study with emulsified aqueous solutions containing crystalline oxalic acid. In those experiments, the crystallisation of oxalic acid diyhdrate was triggered by a preceding homogeneous freezing cycle with the emulsion samples. The expansion cooling cycles with ternary H2SO4/OA

  10. New cloud chamber experiments on the heterogeneous ice nucleation ability of oxalic acid in the immersion mode

    NASA Astrophysics Data System (ADS)

    Wagner, R.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Leisner, T.

    2010-12-01

    The heterogeneous ice nucleation ability of oxalic acid in the immersion mode has been investigated by controlled expansion cooling runs with airborne, ternary solution droplets composed of, (i), sodium chloride, oxalic acid, and water (NaCl/OA/H2O) and, (ii), sulphuric acid, oxalic acid, and water (H2SO4/OA/H2O). Polydisperse aerosol populations with median diameters ranging from 0.5-0.7 μm and varying solute concentrations were prepared. The expansion experiments were conducted in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at initial temperatures of 244 and 235 K. In the ternary NaCl/OA/H2O system, solid inclusions of oxalic acid, presumably nucleated as oxalic acid dihydrate, were formed by temporarily exposing the ternary solution droplets to a relative humidity below the efflorescence point of NaCl. The matrix of the crystallised NaCl particulates triggered the precipitation of the organic crystals which later on remained as solid inclusions in the solution droplets when the relative humidity was again raised above the deliquescence point of NaCl. The embedded oxalic acid crystals reduced the critical ice saturation ratio required for the homogeneous freezing of pure NaCl/H2O solution droplets at a temperature of around 231 K from 1.38 to about 1.32. Aqueous solution droplets with OA inclusions larger than about 0.27 μm in diameter efficiently nucleated ice by condensation freezing when they were activated to micron-sized cloud droplets at 241 K, i.e., they froze well above the homogeneous freezing temperature of pure water droplets of about 237 K. Our results on the immersion freezing potential of oxalic acid corroborate the findings from a recent study with emulsified aqueous solutions containing crystalline oxalic acid. In those experiments, the crystallisation of oxalic acid diyhdrate was triggered by a preceding homogeneous freezing cycle with the emulsion samples. The expansion cooling cycles with ternary H2SO4/OA/H2O

  11. Evaluation of one-dimensional and two-dimensional volatility basis sets in simulating the aging of secondary organic aerosol with smog-chamber experiments.

    PubMed

    Zhao, Bin; Wang, Shuxiao; Donahue, Neil M; Chuang, Wayne; Hildebrandt Ruiz, Lea; Ng, Nga L; Wang, Yangjun; Hao, Jiming

    2015-02-17

    We evaluate the one-dimensional volatility basis set (1D-VBS) and two-dimensional volatility basis set (2D-VBS) in simulating the aging of SOA derived from toluene and α-pinene against smog-chamber experiments. If we simulate the first-generation products with empirical chamber fits and the subsequent aging chemistry with a 1D-VBS or a 2D-VBS, the models mostly overestimate the SOA concentrations in the toluene oxidation experiments. This is because the empirical chamber fits include both first-generation oxidation and aging; simulating aging in addition to this results in double counting of the initial aging effects. If the first-generation oxidation is treated explicitly, the base-case 2D-VBS underestimates the SOA concentrations and O:C increase of the toluene oxidation experiments; it generally underestimates the SOA concentrations and overestimates the O:C increase of the α-pinene experiments. With the first-generation oxidation treated explicitly, we could modify the 2D-VBS configuration individually for toluene and α-pinene to achieve good model-measurement agreement. However, we are unable to simulate the oxidation of both toluene and α-pinene with the same 2D-VBS configuration. We suggest that future models should implement parallel layers for anthropogenic (aromatic) and biogenic precursors, and that more modeling studies and laboratory research be done to optimize the "best-guess" parameters for each layer.

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

    NASA Astrophysics Data System (ADS)

    Englund, Carl-Johan; Agâker, Marcus; Fredriksson, Pierre; Olsson, Anders; Johansson, Niklas; Rubensson, Jan-Erik; Nordgren, Joseph

    2015-09-01

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

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

    SciTech Connect

    Englund, Carl-Johan; Agåker, Marcus Fredriksson, Pierre; Olsson, Anders; Johansson, Niklas; Rubensson, Jan-Erik; Nordgren, Joseph

    2015-09-15

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

  14. Application of the Cluster Counting/Timing techniques to improve the performances of high transparency Drift Chamber for modern HEP experiments

    NASA Astrophysics Data System (ADS)

    Chiarello, G.; Chiri, C.; Cocciolo, G.; Corvaglia, A.; Grancagnolo, F.; Panareo, M.; Pepino, A.; Renga, F.; Tassielli, G. F.; Voena, C.

    2017-07-01

    Ultra-low mass and high granularity Drift Chambers seems to be a better choice for modern HEP experiments, to achieve a good momentum resolution on the charged particle. We present how, in Helium based gas mixture, by counting and measuring the arrival time of each individual ionization cluster and by using statistical tools, it is possible to reconstruct a bias free estimate of the impact parameter and a more discriminant Particle Identification.

  15. Thermal desorption/tunable vacuum-ultraviolet time-of-flight photoionization aerosol mass spectrometry for investigating secondary organic aerosols in chamber experiments.

    PubMed

    Fang, Wenzheng; Gong, Lei; Shan, Xiaobin; Liu, Fuyi; Wang, Zhenya; Sheng, Liusi

    2011-12-01

    This paper describes thermal desorption/tunable vacuum-ultraviolet photoionization time-of-flight aerosol mass spectrometry (TD-VUV-TOF-PIAMS) for the real-time analysis of secondary organic aerosols (SOAs) in smog chamber experiments. SOAs are sampled directly from atmospheric pressure and are focused through an aerodynamic lens assembly into the mass spectrometer. Once the particles have entered the source region, they impact on a heater and are vaporized. The nascent vapor is then softly ionized by tunable VUV synchrotron radiation. TD-VUV-TOF-PIAMS was used in conjunction with the smog chamber to study SOA formation from the photooxidation of toluene with hydroxyl radicals. The ionization energies (IEs) of these SOA products are sometimes very different with each other. As the ideal photon source is tunable, its energy can be adjusted for each molecular to be ionized. The mass spectra obtained at different photon energies are then to be useful for molecular identification. Real-time analysis of the mass spectra of SOAs is compared with previous off-line measurements. These results illustrate the potential of TD-VUV-TOF-PIAMS for direct molecular characterization of SOAs in smog chamber experiments.

  16. Overview of the Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT): mechanistic chamber studies on the oxidation of biogenic compounds

    DOE PAGES

    Nguyen, T. B.; Crounse, J. D.; Schwantes, R. H.; ...

    2014-12-19

    The Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT) was a collaborative atmospheric chamber campaign that occurred during January 2014. FIXCIT is the laboratory component of a synergistic field and laboratory effort aimed toward (1) better understanding the chemical details behind ambient observations relevant to the southeastern United States, (2) advancing the knowledge of atmospheric oxidation mechanisms of important biogenic hydrocarbons, and (3) characterizing the behavior of field instrumentation using authentic standards. Approximately 20 principal scientists from 14 academic and government institutions performed parallel measurements at a forested site in Alabama and at the atmospheric chambers at Caltech.more » During the 4 week campaign period, a series of chamber experiments was conducted to investigate the dark- and photo-induced oxidation of isoprene, α-pinene, methacrolein, pinonaldehyde, acylperoxy nitrates, isoprene hydroxy nitrates (ISOPN), isoprene hydroxy hydroperoxides (ISOPOOH), and isoprene epoxydiols (IEPOX) in a highly controlled and atmospherically relevant manner. Pinonaldehyde and isomer-specific standards of ISOPN, ISOPOOH, and IEPOX were synthesized and contributed by campaign participants, which enabled explicit exploration into the oxidation mechanisms and instrument responses for these important atmospheric compounds. The present overview describes the goals, experimental design, instrumental techniques, and preliminary observations from the campaign. This work provides context for forthcoming publications affiliated with the FIXCIT campaign. Insights from FIXCIT are anticipated to aid significantly in interpretation of field data and the revision of mechanisms currently implemented in regional and global atmospheric models.« less

  17. Automated microbial metabolism laboratory. [design of advanced labeled release experiment based on single addition of soil and multiple sequential additions of media into test chambers

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The design and rationale of an advanced labeled release experiment based on single addition of soil and multiple sequential additions of media into each of four test chambers are outlined. The feasibility for multiple addition tests was established and various details of the methodology were studied. The four chamber battery of tests include: (1) determination of the effect of various atmospheric gases and selection of that gas which produces an optimum response; (2) determination of the effect of incubation temperature and selection of the optimum temperature for performing Martian biochemical tests; (3) sterile soil is dosed with a battery of C-14 labeled substrates and subjected to experimental temperature range; and (4) determination of the possible inhibitory effects of water on Martian organisms is performed initially by dosing with 0.01 ml and 0.5 ml of medium, respectively. A series of specifically labeled substrates are then added to obtain patterns in metabolic 14CO2 (C-14)O2 evolution.

  18. Outdoor smog chamber experiments: reactivity of methanol exhaust. Part 2. Quality assurance and data processing system description

    SciTech Connect

    Jeffries, H.E.; Sexton, K.G.; Kamens, R.M.; Holleman, M.S.

    1985-09-01

    The report describes the Quality Assurance and Data Processing procedures and systems used at the UNC Outdoor Smog Chamber Facility. The primary product of research conducted at this facility is information in the form of measurements of reactants and products in photochemical systems and measurements of the critical parameters that influence the chemical transformations system. Generating useful data begins with understanding the goals of the project and the special needs and concerns of conducting a successful smog-chamber operation. The system components are designed to collect, transfer, process, and report accurate, high-resolution data without loss or distortion. The system components in the Quality Assurance and Data Processing system are: people, hardware, software, checklists, and data bases. Quality-assurance checks are made at every level of the program. Pressurized gas-tank and liquid mixtures were used to establish experimental conditions of HC assuring consistency throughout the program. Several NBS traceable standards and liquid injections into the chamber used for calibration have been intercompared and show good agreement.

  19. Automated Electrostatics Environmental Chamber

    NASA Technical Reports Server (NTRS)

    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. Target Chamber Manipulator

    NASA Astrophysics Data System (ADS)

    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.

  1. Development of Hyperon Time-Projection-Chamber (HypTPC) for the H-Dibaryon Search Experiment at J-PARC

    NASA Astrophysics Data System (ADS)

    Hwang, Sanghoon; Imai, Kenichi; Ahn, Jung Keun

    We the E42 collaboration proposed to search for the H-dibaryon in ΛΛ production from (K-, K-) reaction off nuclei by using a high-intensity K- beam at J-PARC with 100 times better statistics than KEK-E224 and E552 experiments. Our proposed experiment will be designed to confirm if the enhancement is due to the H-dibaryon as a ΛΛ resonance or a virtual bound state or ΛΛ final state interaction. We plan to construct a large-acceptance hyperon spectrometer with a Time-Projection-Chamber (HypTPC) to detector ΛΛ particles, simultaneously K+ particle is measured by the KURAMA spectrometer. We expect to collect 11000 ΛΛ events with a mass resolution of 1.0 MeV/c2 near the ΛΛ threshold. The sensitivity of the detector shows two orders of magitude improvement from the present limit.

  2. Neutron detection via bubble chambers.

    PubMed

    Jordan, D V; Ely, J H; Peurrung, A J; Bond, L J; Collar, J I; Flake, M; Knopf, M A; Pitts, W K; Shaver, M; Sonnenschein, A; Smart, J E; Todd, L C

    2005-01-01

    Research investigating the application of pressure-cycled bubble chambers to fast neutron detection is described. Experiments with a Halon-filled chamber showed clear sensitivity to an AmBe neutron source and insensitivity to a (137)Cs gamma source. Bubble formation was documented using high-speed photography, and a ceramic piezo-electric transducer element registered the acoustic signature of bubble formation. In a second set of experiments, the bubble nucleation response of a Freon-134a chamber to an AmBe neutron source was documented with high-speed photography.

  3. Release of Reactive Halogen Species from Sea-Salt Aerosols under Tropospheric Conditions with/without the Influence of Organic Matter in Smog-Chamber Experiments

    NASA Astrophysics Data System (ADS)

    Balzer, N.; Behnke, W.; Bleicher, S.; Krueger, H.; Ofner, J.; Siekmann, F.; Zetzsch, C.

    2008-12-01

    Experiments to investigate the release of reactive halogen species from sea-salt aerosol and the influence of organic matter were performed in an aerosol smog-chamber (3500 l), made of Teflon film (FEP 200A, Dupont). Smog chamber facilities at lowered temperature (coolable down to -25°C) enable us to simulate these reactions under polar, tropospheric conditions. First experiments were performed to investigate the production of atomic Br and Cl without the impact of organic aerosol. Br and Cl play an important role in atmospheric ozone depletion, particularly regarding ozone depletion events (bromine explosion) during polar spring. In these studies, the aerosol was generated by atomizing salt solutions containing the typical Br/Cl ratio of 1/660 in seawater by an ultrasonic nebulizer and increasing the Br content up to sixfold. To ensure the aqueous surface of the aerosol, the experiments were performed at relative humidities above 76%. We determined the atomic Cl and OH-radical concentrations from the simultaneous consumption of four reference hydrocarbons. The Br-radical concentration was calculated on the basis of ozone depletion. Organic aerosol may take part in these reaction cycles by halogenation and production of volatile organic halogens. Further experiments are planned to add organic aerosol for mechanistic and kinetic studies on the influence of secondary organic aerosols (SOA) and humic-like substances (HULIS) on bromine explosion. The formation of the secondary organic aerosol and the determination of possible halogenated gaseous and solid organic products will be studied using longpath-FTIR, DRIFTS, ATR-FTIR, GC-FID, GC-ECD, GC-MS, TPD-MS and DMA-CNC.

  4. Dormancy release of Norway spruce under climatic warming: testing ecophysiological models of bud burst with a whole-tree chamber experiment.

    PubMed

    Hänninen, Heikki; Slaney, Michelle; Linder, Sune

    2007-02-01

    Ecophysiological models predicting timing of bud burst were tested with data gathered from 40-year-old Norway spruce (Picea abies (L.) Karst.) trees growing in northern Sweden in whole-tree chambers under climatic conditions predicted to prevail in 2100. Norway spruce trees, with heights between 5 and 7 m, were enclosed in individual chambers that provided a factorial combination of ambient (365 micromol mol-1) or elevated (700 micromol mol-1) atmospheric CO2 concentration, [CO2], and ambient or elevated air temperature. Temperature elevation above ambient ranged from +2.8 degrees C in summer to +5.6 degrees C in winter. Compared with control trees, elevated air temperature hastened bud burst by 2 to 3 weeks, whereas elevated [CO2] had no effect on the timing of bud burst. A simple model based on the assumption that bud rest completion takes place on a fixed calendar day predicted timing of bud burst more accurately than two more complicated models in which bud rest completion is caused by accumulated chilling. Together with some recent studies, the results suggest that, in adult trees, some additional environmental cues besides chilling are required for bud rest completion. Although it appears that these additional factors will protect trees under predicted climatic warming conditions, increased risk of frost damage associated with earlier bud burst cannot be ruled out. Inconsistent and partially anomalous results obtained in the model fitting show that, in addition to phenological data gathered under field conditions, more specific data from growth chamber and greenhouse experiments are needed for further development and testing of the models.

  5. Chamber dynamic research with pulsed power

    SciTech Connect

    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.

  6. Competitive adsorption/desorption of tetracycline, oxytetracycline and chlortetracycline on two acid soils: Stirred flow chamber experiments.

    PubMed

    Fernández-Calviño, David; Bermúdez-Couso, Alipio; Arias-Estévez, Manuel; Nóvoa-Muñoz, Juan Carlos; Fernández-Sanjurjo, Maria J; Álvarez-Rodríguez, Esperanza; Núñez-Delgado, Avelino

    2015-09-01

    The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred flow chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Performance of Current-Mode Ion Chambers as Beam Monitors in a Pulsed Cold Neutron Beam for the NPDGamma experiment

    NASA Astrophysics Data System (ADS)

    Gillis, R. Chad

    2006-10-01

    The NPDGamma collaboration has built and commissioned an apparatus to measure the parity-violating gamma asymmetry A in the low energy np capture process n+p->d+ γ. The asymmetry in question is a 10-8 correlation between the spin of the incident (polarized) neutron and the outgoing 2.2 MeV gamma ray. A set of purpose-built, 3He-filled ionization chambers read out in current mode is used to monitor the incident neutron flux, the beam polarization, and the transmission of the liquid para-hydrogen target during the NPDGamma measurements. As will be described in the talk, these beam monitors are simple, reliable, low-noise detectors that have performed excellently for NPDGamma. We have verified that the beam monitor signals can be interpreted to reproduce the known time-of-flight dependence of beam flux from the LANSCE pulsed cold neutron source, and that the neutron beam polarization can be measured at the 2% level from direct measurements of the transmission of the beam through the beam polarizer.

  8. Cardiac chambers perforation by pacemaker and cardioverter-defibrillator leads. Own experience in diagnosis, treatment and preventive methods.

    PubMed

    Maziarz, Andrzej; Ząbek, Andrzej; Małecka, Barbara; Kutarski, Andrzej; Lelakowski, Jacek

    2012-01-01

    Cardiac chamber perforation is an uncommon, but potentially dangerous, complication of implantation of a pacemaker (PM) or a cardioverter-defibrillator (ICD). Different clinical presentations are related to the time between implantation and perforation, localisation of the perforation and concomitant lesions in neighbouring organs. Diagnosis is based on concomitant analysis of the clinical picture, ECG tracings, PM or ICD function check-up with a programmer, and review of echocardiographic, X-ray and computed tomography pictures. We analysed seven cases of perforation. Perforating leads were removed in all cases and a new pacing system was implanted in five cases. Choice of operative technique (unscrewing and direct traction from device pocket, Cook system or surgical procedure with pericardial drainage) depended on the time elapsing between implantation and perforation, the presence of lesions of other organs, and the amount of fluid in the pericardial sac. Avoiding unsafe localisation of a pacing electrode in the apex and free wall of the right ventricle and in the free anterolateral wall of the right atrium, and avoiding leaving an extra length of pacing lead under tension and overscrewing of the lead helix seem to be the best ways of prevention.

  9. Uniform-Temperature Walls for Cloud Chambers

    NASA Technical Reports Server (NTRS)

    Fleischman, G.

    1985-01-01

    Flat heat pipes rapidly transfer heat to and from experimental volumes. Heat pipe vapor chamber carries heat to and from thermo electric modules. Critical surface acts as evaporator or condenser in cloud physics experiments. Used as walls of spaceborne atmospheric cloud chambers. On Earth, used as isothermal floors for environmental test chambers.

  10. Uniform-Temperature Walls for Cloud Chambers

    NASA Technical Reports Server (NTRS)

    Fleischman, G.

    1985-01-01

    Flat heat pipes rapidly transfer heat to and from experimental volumes. Heat pipe vapor chamber carries heat to and from thermo electric modules. Critical surface acts as evaporator or condenser in cloud physics experiments. Used as walls of spaceborne atmospheric cloud chambers. On Earth, used as isothermal floors for environmental test chambers.

  11. Simple Cloud Chambers Using Gel Ice Packs

    ERIC Educational Resources Information Center

    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…

  12. EPA GAS PHASE CHEMISTRY CHAMBER STUDIES

    EPA Science Inventory

    Gas-phase smog chamber experiments are being performed at EPA in order to evaluate a number of current chemical mechanisms for inclusion in EPA regulatory and research models. The smog chambers are 9000 L in volume and constructed of 2-mil teflon film. One of the chambers is co...

  13. Simple Cloud Chambers Using Gel Ice Packs

    ERIC Educational Resources Information Center

    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…

  14. EPA GAS PHASE CHEMISTRY CHAMBER STUDIES

    EPA Science Inventory

    Gas-phase smog chamber experiments are being performed at EPA in order to evaluate a number of current chemical mechanisms for inclusion in EPA regulatory and research models. The smog chambers are 9000 L in volume and constructed of 2-mil teflon film. One of the chambers is co...

  15. SU-E-T-150: Brachytherapy QA Employing a High Resolution Liquid Filled Ionisation Chamber Array: Initial Experience and Limitations

    SciTech Connect

    Gainey, M; Kollefrath, M; Bruggmoser, G

    2015-06-15

    Purpose: Verifying a complex 3D brachytherapy dose distribution by measurement is non-trivial. Ideally a photon detector array should be independent of energy and angle, have high spatial resolution and be robust for routine clinical use. Methods: An iridium-192 source was used. A PMMA jig was constructed comprising an outer slab and a central insert with eight milled channels for 1.33mm (outer diameter) steel needles, see figure. All calculations were performed using an empty CT study reconstructing eight virtual needles (QA-CT), using the v2 source model (Elekta AG, Sweden). A high resolution liquid filled ionisation chamber array SRS1000, together with Verisoft software v6.0 (PTW Freiburg, Germany), was used to perform measurements of plans of increasing complexity to evaluate its suitability for device- and patient-specific QA. The dimension of backscatter material was investigated. The patient plan dwell time distribution was entered manually into the QA-CT and the dose distribution was calculated. Results: Our measurements indicate that the array is independent of energy and angle. The resulting measured dose values are linearly interpolated to 2025 values. Shifts of 1mm of the entire needle are readily detectable. Individual dwell position shifts (2.5mm) are also readily measurable. Moreover a dwell time increase of 1 second both in the edge and central region are detectable. Conclusion: The high resolution SRS1000 array is a powerful instrument for brachytherapy QA enabling 977 simultaneous measurements to be performed. Our measurements suggest 60mm of RW3 backscatter material upstream and downstream are sufficient. Local percentage difference analysis is useful for device based QA, normalized relative percentage difference is arguably better for patient specific QA. Automated transfer of patient plan dwell time distribution to the QA plan is required to enable a comprehensive patient QA study to be performed. Moreover the described measurement technique

  16. Multidimensional analysis of data obtained in experiments with X-ray emulsion chambers and extensive air showers

    NASA Technical Reports Server (NTRS)

    Chilingaryan, A. A.; Galfayan, S. K.; Zazyan, M. Z.; Dunaevsky, A. M.

    1985-01-01

    Nonparametric statistical methods are used to carry out the quantitative comparison of the model and the experimental data. The same methods enable one to select the events initiated by the heavy nuclei and to calculate the portion of the corresponding events. For this purpose it is necessary to have the data on artificial events describing the experiment sufficiently well established. At present, the model with the small scaling violation in the fragmentation region is the closest to the experiments. Therefore, the treatment of gamma families obtained in the Pamir' experiment is being carried out at present with the application of these models.

  17. Two-dimensional numerical models of open-top hydrothermal convection at high Rayleigh and Nusselt numbers: Implications for mid-ocean ridge hydrothermal circulation

    NASA Astrophysics Data System (ADS)

    Fontaine, Fabrice J.; Wilcock, William S. D.

    2007-07-01

    Mid-ocean ridges host vigorous hydrothermal systems that remove large quantities of heat from the oceanic crust. Inferred Nusselt numbers (Nu), which are the ratios of the total heat flux to the heat flux that would be transported by conduction alone, range from 8 to several hundred. Such vigorous convection is not fully described by most numerical models of hydrothermal circulation. A major difficulty arises at high Nu from the numerical solution of the temperature equation. To avoid classical numerical artifacts such as nonphysical oscillatory behavior and artificial diffusion, we implement the Multidimensional Positive Definite Advection Transport Algorithm (MPDATA) technique, which solves the temperature equation using an iterated upwind corrected scheme. We first validate the method by comparing results for models with uniform fluid properties in closed- and open-top systems to existing solutions with Nu ≤ ˜20. We then incorporate realistic fluid properties and run models for Nu up to 50-60. Solutions are characterized by an unstable bottom thermal boundary layer where thermal instabilities arise locally. The pattern of heat extraction is periodic to chaotic. At any Nu > ˜13 the venting temperatures in a given plume are chaotic and oscillate from ˜350° to 450°C. Individual plumes can temporarily stop short of the surface for intervals ranging from tens to hundreds of years at times when other plumes vent with an increased flow rate. The solutions also display significant recirculation, and as a result large areas of downflow are relatively warm with temperatures commonly exceeding 150°C at middepths. Our results have important implications for mid-ocean ridge hydrothermal systems and suggest the following: (1) The reaction zones of mid-ocean ridge hydrothermal systems are enlarged by thermal instabilities that migrate laterally toward upflow zones. This will substantially increase the volume of rock involved in chemical reactions compared to steady

  18. Commissioning of the ArDM experiment at the Canfranc underground laboratory: first steps towards a tonne-scale liquid argon time projection chamber for Dark Matter searches

    NASA Astrophysics Data System (ADS)

    Calvo, J.; Cantini, C.; Crivelli, P.; Daniel, M.; Di Luise, S.; Gendotti, A.; Horikawa, S.; Montes, B.; Mu, W.; Murphy, S.; Natterer, G.; Nguyen, K.; Periale, L.; Quan, Y.; Radics, B.; Regenfus, C.; Romero, L.; Rubbia, A.; Santorelli, R.; Sergiampietri, F.; Viant, T.; Wu, S.

    2017-03-01

    The Argon Dark Matter (ArDM) experiment consists of a liquid argon (LAr) time projection chamber (TPC) sensitive to nuclear recoils, resulting from scattering of hypothetical Weakly Interacting Massive Particles (WIMPs) on argon targets. With an active target mass of 850 kg ArDM represents an important milestone towards developments for large LAr Dark Matter detectors. Here we present the experimental apparatus currently installed underground at the Laboratorio Subterráneo de Canfranc (LSC), Spain. We show data on gaseous or liquid argon targets recorded in 2015 during the commissioning of ArDM in single phase at zero E-field (ArDM Run I). The data confirms the overall good and stable performance of the ArDM tonne-scale LAr detector.

  19. Comparative Analysis of Anterior Chamber Flare Grading between Clinicians with Different Levels of Experience and Semi-automated Laser Flare Photometry.

    PubMed

    Agrawal, Rupesh; Keane, Pearse A; Singh, Jasmin; Saihan, Zubin; Kontos, Andreas; Pavesio, Carlos E

    2016-01-01

    To assess correlation for anterior chamber flare grading between clinicians with different levels of experience and with semi-automated flare reading in a cohort of patients with heterogeneous uveitic entities. Fifty-nine observations from 36 patients were recorded and analyzed for statistical association. In each patient, flare was assessed objectively using the Kowa FM-700 laser flare photometer, and subjective masked grading by two clinicians was performed. The study demonstrated disparity in flare readings between clinical graders with one step disagreement in clinical grading in 26 (44.06%) eyes (p < 0.001) and concordance between the flare readings by experienced grader and flare photometry. After review of semi-automated flare readings, management was changed in 11% of the patients. Laser flare photometry can be a valuable tool to remove the observer bias in grading flare for selected cohort of uveitis patients. It can be further applied to titrate therapy in intraocular inflammation.

  20. Multiwire proportional chamber development

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  1. Aerosol and gas phase organic acids during aging of secondary organic aerosol from α-pinene in smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Praplan, Arnaud P.; Tritscher, Torsten; Barmet, Peter; Mertes, Peter; Decarlo, Peter F.; Dommen, Josef; Prevot, Andre S. H.; Donahue, Neil M.; Baltensperger, Urs

    2010-05-01

    Organic acids represent an important class of organic compounds in the atmosphere for both the gas and aerosol phase. They are either emitted directly from both biogenic and anthropogenic sources or formed as oxidation products from volatile organic compounds (VOCs) and precursors in the aqueous, gaseous and particle phase (Chebbi & Carlier, 1996) Monoterpenes are a prominent class of VOCs with annual emissions of 127 Tg per year (Guenther et al., 1995). Because of their high formation potential of secondary organic aerosols, several compounds of this class, particularly a-pinene, have been investigated extensively in many laboratory studies. Among other acids, cis-pinic and cis-pinonic acid have been found as products of a-pinene ozonolysis. Ma et al. (2007) published evidence that these organic acids are formed in the gas phase via Criegee Intermediates (CIs). Recently, 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) was identified by Szmigielski et al. (2007) as a product from a-pinene photooxidation, as well as diaterpenylic acid acetate (Iinuma et al., 2009) and terpenylic acid (Claeys et al., 2009). These compounds could serve as tracers for a-pinene in ambient samples. The present work sets its focus on the fate of a-pinene SOA organic acids under different aging conditions. (1) low NOx concentration (2) high NOx concentration (3) exposure to OH radicals in both dark and lighted environments. a-pinene SOA is produced by ozonolysis without OH scavenger in the PSI smog chamber. It consists of a 27m3 Teflon® bag that can be irradiated by four Xe arc lamps to simulate sunlight (Paulsen et al., 2004). The organic acids are sampled with a wet effluent diffusion denuder (WEDD) and an aerosol collector (AC) for the gas phase and the aerosol particles, respectively. WEDD and AC samples are alternatively concentrated for 30 minutes on a trace anion concentrator (TAC) column (Dionex, Switzerland) and subsequently analyzed by ion chromatography coupled to mass

  2. Chamber QoE: a multi-instrumental approach to explore affective aspects in relation to quality of experience

    NASA Astrophysics Data System (ADS)

    De Moor, Katrien; Mazza, Filippo; Hupont, Isabelle; Ríos Quintero, Miguel; Mäki, Toni; Varela, Martín.

    2014-02-01

    Evaluating (audio)visual quality and Quality of Experience (QoE) from the user's perspective, has become a key element in optimizing users' experiences and their quality. Traditionally, the focus lies on how multi-level quality features are perceived by a human user. The interest has however gradually expanded towards human cognitive, affective and behavioral processes that may impact on, be an element of, or be influenced by QoE, and which have been underinvestigated so far. In addition, there is a major discrepancy between the new, broadly supported and more holistic conceptualization of QoE proposed by Le Callet et al. (2012) and traditional, standardized QoE assessment. This paper explores ways to tackle this discrepancy by means of a multi-instrumental approach. More concretely, it presents results from a lab study on video quality (N=27), aimed at going beyond the dominant QoE assessment paradigm and at exploring affective aspects in relation to QoE and in relation to perceived overall quality. Four types of data were collected: `traditional' QoE self-report measures were complemented with `alternative', emotional state- and user engagement-related self-report measures to evaluate QoE. In addition, we collected EEG (physiological) data, gazetracking data and facial expressions (behavioral) data. The video samples used in test were longer in duration than is common in standard tests allowing us to study e.g. more realistic experience and deeper user engagement. Our findings support the claim that the traditional QoE measures need to be reconsidered and extended with additional, affective staterelated measures.

  3. Readout channel with majority logic timestamp and digital peak detector for Muon Chambers of the CBM experiment

    NASA Astrophysics Data System (ADS)

    Atkin, E.; Bulbakov, I.; Ivanov, P.; Ivanov, V.; Malankin, E.; Normanov, D.; Sagdiev, I.; Samsonov, V.; Shumikhin, V.; Shumkin, O.; Vinogradov, S.; Voronin, A.

    2016-12-01

    A prototype readout channel was manufactured in UMC CMOS 180 nm for the purpose of the CBM experiment at the FAIR accelerator. The channel includes a preamplifier with fast and slow CR-RC shapers, discriminator with a differential threshold setup circuit, a 6-bit SAR ADC (DNL = 0.70, INL = 0.45), digital peak detector and block of the time stamp registration. The control data, clock and output data are supplied through SLVS transmitter and receiver. The slow and fast channels have 1000 el and 1500 el ENC accordingly at a 50 pF detector capacitance. Power consumption is 10 mW/channel.

  4. Coastal iodine emissions: part 2. Chamber experiments of particle formation from Laminaria digitata-derived and laboratory-generated I₂.

    PubMed

    Monahan, Ciaran; Ashu-Ayem, Enowmbi R; Nitschke, Udo; Darby, Steven B; Smith, Paul D; Stengel, Dagmar B; Venables, Dean S; O'Dowd, Colin D

    2012-10-02

    Laboratory studies into particle formation from Laminaria digitata macroalgae were undertaken to elucidate aerosol formation for a range of I(2) (0.3-76 ppb(v)) and O(3) (<3-96 ppb(v)) mixing ratios and light levels (E(PAR) = 15, 100, and 235 μmol photons m(-2) s(-1)). No clear pattern was observed for I(2) or aerosol parameters as a function of light levels. Aerosol mass fluxes and particle number concentrations, were, however, correlated with I(2) mixing ratios for low O(3) mixing ratios of <3 ppb(v) (R(2) = 0.7 and 0.83, respectively for low light levels, and R(2) = 0.95 and 0.98, respectively for medium light levels). Additional experiments into particle production as a function of laboratory-generated I(2), over a mixing ratio range of 1-8 ppb(v), were conducted under moderate O(3) mixing ratios (∼24 ppb(v)) where a clear, 100-fold or greater, increase in the aerosol number concentrations and mass fluxes was observed compared to the low O(3) experiments. A linear relationship between particle concentration and I(2) was found, in reasonable agreement with previous studies. Scaling the laboratory relationship to aerosol concentrations typical of the coastal boundary layer suggests a I(2) mixing ratio range of 6-93 ppt(v) can account for the observed particle production events. Aerosol number concentration produced from I(2) is more than a factor of 10 higher than that produced from CH(2)I(2) for the same mixing ratios.

  5. Portable Hyperbaric Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, William C. (Inventor); Locke, James P. (Inventor); DeLaFuente, Horacio (Inventor)

    2001-01-01

    A portable, collapsible hyperbaric chamber was developed. A toroidal inflatable skeleton provides initial structural support for the chamber, allowing the attendant and/or patient to enter the chamber. Oval hatches mate against bulkhead rings, and the hyperbaric chamber is pressurized. The hatches seal against an o-ring, and the internal pressure of the chamber provides the required pressure against the hatch to maintain an airtight seal. In the preferred embodiment, the hyperbaric chamber has an airlock to allow the attendant to enter and exit the patient chamber during treatment. Visual communication is provided through portholes in the patient and/or airlock chamber. Life monitoring and support systems are in communication with the interior of the hyperbaric chamber and/or airlock chamber through conduits and/or sealed feed-through connectors into the hyperbaric chamber.

  6. Portable Hyperbaric Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, William C. (Inventor); Locke, James P. (Inventor); DeLaFuente, Horacio (Inventor)

    2001-01-01

    A portable, collapsible hyperbaric chamber was developed. A toroidal inflatable skeleton provides initial structural support for the chamber, allowing the attendant and/or patient to enter the chamber. Oval hatches mate against bulkhead rings, and the hyperbaric chamber is pressurized. The hatches seal against an o-ring, and the internal pressure of the chamber provides the required pressure against the hatch to maintain an airtight seal. In the preferred embodiment, the hyperbaric chamber has an airlock to allow the attendant to enter and exit the patient chamber during treatment. Visual communication is provided through portholes in the patient and/or airlock chamber. Life monitoring and support systems are in communication with the interior of the hyperbaric chamber and/or airlock chamber through conduits and/or sealed feed-through connectors into the hyperbaric chamber.

  7. How seasonal temperature or water inputs affect the relative response of C3 crops to elevated [CO2]: A global analysis of open top chamber and Free Air CO2 Enrichment (FACE) studies

    USDA-ARS?s Scientific Manuscript database

    Rising atmospheric carbon dioxide concentration ([CO2]) has the potential to positively impact C3 food crop production by directly stimulating photosynthetic carbon gain (A), which feeds forward to increase crop biomass and yield. Further stimulation of A and yield can result from an indirect mechan...

  8. Interactive effect of supplemental ultraviolet B and elevated ozone on seed yield and oil quality of two cultivars of linseed (Linum usitatissimum L.) carried out in open top chambers.

    PubMed

    Tripathi, Ruchika; Agrawal, Shashi B

    2013-03-30

    Current scenarios of global climate change predict a significant increase in ultraviolet B (UV-B) and tropospheric ozone (O₃) in the near future. Both UV-B and O₃ can have detrimental effects on the productivity and yield quality of important agricultural crops. The present study was conducted to investigate the individual and interactive effects of supplemental UV-B (sUV-B) (ambient + 7.2 kJ m⁻² day⁻¹) and O₃ (ambient + 10 ppb) on the yield and oil quality of two cultivars of linseed (Linum usitatissimum L.). The mean monthly ambient O₃ concentration varied from 27.7 to 59.0 ppb during the experimental period. O₃ affected fruit formation, while sUV-B was mainly responsible for ovule abortion. Seed sugar and protein contents showed maximum reduction in O₃-treated plants, while mineral nutrient levels were most affected by sUV-B + O₃ treatment. Rancid oil of low nutritional quality and containing long-chain fatty acids was favoured along with a decrease in oil content. sUV-B and O₃ individually as well as in combination caused deterioration of the yield and quality of oil and seeds of linseed. However, the individual effect of O₃ was more damaging than the effect of sUV-B or sUV-B + O₃, and cultivar T-397 performed better than Padmini. © 2012 Society of Chemical Industry.

  9. Gas-particle partitioning and hydrolysis of organic nitrates formed from the oxidation of α-pinene in environmental chamber experiments

    NASA Astrophysics Data System (ADS)

    Bean, Jeffrey K.; Hildebrandt Ruiz, Lea

    2016-02-01

    Gas-particle partitioning and hydrolysis of organic nitrates (ON) influences their role as sinks and sources of NOx and their effects on the formation of tropospheric ozone and organic aerosol (OA). In this work, organic nitrates were formed from the photo-oxidation of α-pinene in environmental chamber experiments under different conditions. Particle-phase ON hydrolysis rates, consistent with observed ON decay, exhibited a nonlinear dependence on relative humidity (RH): an ON decay rate of 2 day-1 was observed when the RH ranged between 20 and 60 %, and no significant ON decay was observed at RH lower than 20 %. In experiments when the highest observed RH exceeded the deliquescence RH of the ammonium sulfate seed aerosol, the particle-phase ON decay rate was as high as 7 day-1 and more variable. The ON gas-particle partitioning was dependent on total OA concentration and temperature, consistent with absorptive partitioning theory. In a volatility basis set, the ON partitioning was consistent with mass fractions of [0 0.11 0.03 0.86] at saturation mass concentrations (C*) of [1 10 100 1000] µg m-3.

  10. SU-E-T-448: On the Perturbation Factor P-cav of the Markus Parallel Plate Ion Chambers in Clinical Electron Beams, Monte Carlo Based Reintegration of An Historical Experiment

    SciTech Connect

    Voigts-Rhetz, P von; Zink, K

    2014-06-01

    Purpose: All present dosimetry protocols recommend well-guarded parallel-plate ion chambers for electron dosimetry. For the guard-less Markus chamber an energy dependent fluence perturbation correction pcav is given. This perturbation correction was experimentally determined by van der Plaetsen by comparison of the read-out of a Markus and a NACP chamber, which was assumed to be “perturbation-free”. Aim of the present study is a Monte Carlo based reiteration of this experiment. Methods: Detailed models of four parallel-plate chambers (Roos, Markus, NACP and Advanced Markus) were designed using the Monte Carlo code EGSnrc and placed in a water phantom. For all chambers the dose to the active volume filled with low density water was calculated for 13 clinical electron spectra (E{sub 0}=6-21 MeV) at the depth of maximum and at the reference depth under reference conditions. In all cases the chamber's reference point was positioned at the depth of measurement. Moreover, the dose to water DW was calculated in a small water voxel positioned at the same depth. Results: The calculated dose ratio D{sub NACP}/D{sub Markus}, which according to van der Plaetsen reflects the fluence perturbation correction of the Markus chamber, deviates less from unity than the values given by van der Plaetsen's but exhibits a similar energy dependence. The same holds for the dose ratios of the other well guarded chambers. But, in comparison to water, the Markus chamber reveals the smallest overall perturbation correction which is nearly energy independent at both investigated depths. Conclusion: The simulations principally confirm the energy dependence of the dose ratio D{sub NACP}/D{sub Markus} as published by van der Plaetsen. But, as shown by our simulations of the ratio D{sub W}/D{sub Markus}, the conclusion drawn in all dosimetry protocols is questionable: in contrast to all well-guarded chambers the guard-less Markus chamber reveals the smallest overall perturbation correction and

  11. The APS ceramic chambers

    SciTech Connect

    Milton, S.; Warner, D.

    1994-07-01

    Ceramics chambers are used in the Advanced Photon Source (APS) machines at the locations of the pulsed kicker and bumper magnets. The ceramic will be coated internally with a resistive paste. The resistance is chosen to allow the low frequency pulsed magnet field to penetrate but not the high frequency components of the circulating beam. Another design goal was to keep the power density experienced by the resistive coating to a minimum. These ceramics, their associated hardware, the coating process, and our recent experiences with them are described.

  12. Holography in small bubble chambers

    SciTech Connect

    Lecoq, P.

    1984-01-01

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

  13. Improved Bakeout Chambers Within Vacuum Chambers

    NASA Technical Reports Server (NTRS)

    Johnson, Kenneth R.; Taylor, Daniel M.; Lane, Robert W.; Cortez, Maximo G.; Anderson, Mark R.

    1995-01-01

    Improved bakeout chamber incorporates hardware features that, in conjunction with improved bakeout procedure, reduce spurious contamination and increase accuracy of contamination measurements. When operated according to revised bakeout procedure, they yield measurements of contamination on vacuum-bake test articles more accurate than available previously, and potential for post-bake recontamination of vacuum-baked articles reduced. These chambers improved versions of one described in "Bakeout Chamber Within Vacuum Chamber" (NPO-18959). By enclosing test article in enclave and keeping walls of enclave hotter than test article during bakeout, one prevents condensation of contaminants on inner walls of enclave.

  14. Assessing the influence of NOx concentrations and relative humidity on secondary organic aerosol yields from α-pinene photo-oxidation through smog chamber experiments and modelling calculations

    NASA Astrophysics Data System (ADS)

    Stirnweis, Lisa; Marcolli, Claudia; Dommen, Josef; Barmet, Peter; Frege, Carla; Platt, Stephen M.; Bruns, Emily A.; Krapf, Manuel; Slowik, Jay G.; Wolf, Robert; Prévôt, Andre S. H.; Baltensperger, Urs; El-Haddad, Imad

    2017-04-01

    Secondary organic aerosol (SOA) yields from the photo-oxidation of α-pinene were investigated in smog chamber (SC) experiments at low (23-29 %) and high (60-69 %) relative humidity (RH), various NOx / VOC ratios (0.04-3.8) and with different aerosol seed chemical compositions (acidic to neutralized sulfate-containing or hydrophobic organic). A combination of a scanning mobility particle sizer and an Aerodyne high-resolution time-of-flight aerosol mass spectrometer was used to determine SOA mass concentration and chemical composition. We used a Monte Carlo approach to parameterize smog chamber SOA yields as a function of the condensed phase absorptive mass, which includes the sum of OA and the corresponding bound liquid water content. High RH increased SOA yields by up to 6 times (1.5-6.4) compared to low RH. The yields at low NOx / VOC ratios were in general higher compared to yields at high NOx / VOC ratios. This NOx dependence follows the same trend as seen in previous studies for α-pinene SOA. A novel approach of data evaluation using volatility distributions derived from experimental data served as the basis for thermodynamic phase partitioning calculations of model mixtures in this study. These calculations predict liquid-liquid phase separation into organic-rich and electrolyte phases. At low NOx conditions, equilibrium partitioning between the gas and liquid phases can explain most of the increase in SOA yields observed at high RH, when in addition to the α-pinene photo-oxidation products described in the literature, fragmentation products are added to the model mixtures. This increase is driven by both the increase in the absorptive mass and the solution non-ideality described by the compounds' activity coefficients. In contrast, at high NOx, equilibrium partitioning alone could not explain the strong increase in the yields with RH. This suggests that other processes, e.g. reactive uptake of semi-volatile species into the liquid phase, may occur and be

  15. Tests of anechoic chamber for aeroacoustics investigations

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  16. Comparison of OH concentration measurements by DOAS and LIF during SAPHIR chamber experiments at high OH reactivity and low NO concentration

    NASA Astrophysics Data System (ADS)

    Fuchs, H.; Dorn, H.-P.; Bachner, M.; Bohn, B.; Brauers, T.; Gomm, S.; Hofzumahaus, A.; Holland, F.; Nehr, S.; Rohrer, F.; Tillmann, R.; Wahner, A.

    2012-07-01

    During recent field campaigns, hydroxyl radical (OH) concentrations that were measured by laser-induced fluorescence (LIF) were up to a factor of ten larger than predicted by current chemical models for conditions of high OH reactivity and low NO concentration. These discrepancies, which were observed in forests and urban-influenced rural environments, are so far not entirely understood. In summer 2011, a series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, in order to investigate the photochemical degradation of isoprene, methyl-vinyl ketone (MVK), methacrolein (MACR) and aromatic compounds by OH. Conditions were similar to those experienced during the PRIDE-PRD2006 campaign in the Pearl River Delta (PRD), China, in 2006, where a large difference between OH measurements and model predictions was found. During experiments in SAPHIR, OH was simultaneously detected by two independent instruments: LIF and differential optical absorption spectroscopy (DOAS). Because DOAS is an inherently calibration-free technique, DOAS measurements are regarded as a reference standard. The comparison of the two techniques was used to investigate potential artifacts in the LIF measurements for PRD-like conditions of OH reactivities of 10 to 30 s-1 and NO mixing ratios of 0.1 to 0.3 ppbv. The analysis of twenty experiment days shows good agreement. The linear regression of the combined data set (averaged to the DOAS time resolution, 2495 data points) yields a slope of 1.02 ± 0.01 with an intercept of (0.10 ± 0.03) × 106 cm-3 and a linear correlation coefficient of R2 = 0.86. This indicates that the sensitivity of the LIF instrument is well-defined by its calibration procedure. No hints for artifacts are observed for isoprene, MACR, and different aromatic compounds. LIF measurements were approximately 30-40% (median) larger than those by DOAS after MVK (20 ppbv) and toluene (90 ppbv) had been added. However, this discrepancy has a

  17. CONTINUOUS ROTATION SCATTERING CHAMBER

    DOEpatents

    Verba, J.W.; Hawrylak, R.A.

    1963-08-01

    An evacuated scattering chamber for use in observing nuclear reaction products produced therein over a wide range of scattering angles from an incoming horizontal beam that bombards a target in the chamber is described. A helically moving member that couples the chamber to a detector permits a rapid and broad change of observation angles without breaching the vacuum in the chamber. Also, small inlet and outlet openings are provided whose size remains substantially constant. (auth)

  18. Long-term natural history and postoperative outcome of double-chambered right ventricle--experience from two tertiary adult congenital heart centres and review of the literature.

    PubMed

    Kahr, Peter C; Alonso-Gonzalez, Rafael; Kempny, Aleksander; Orwat, Stefan; Uebing, Anselm; Dimopoulos, Konstantinos; Swan, Lorna; Baumgartner, Helmut; Gatzoulis, Michael A; Diller, Gerhard-Paul

    2014-07-01

    Double-chambered right ventricle (DCRV) is a rare form of congenital heart disease. Little is known about the outcome during adult life. Here we report the combined experience of two tertiary Adult Congenital Heart Disease Centres and systematically review the published literature. 50 patients (32 female, median age 39 years [IQR: 27;53]) with DCRV under follow-up could be identified. A retrospective review of medical records was performed. Almost all patients (96%) had ventricular septal defects as underlying diagnosis. Eight patients remained completely asymptomatic during follow-up and have been managed conservatively thus far. The remaining patients developed symptoms at a median age of 26 years. Surgical correction was performed in 33 patients (median age at operation 27 years). No residual intraventricular gradient was present at the latest follow-up in 91% of operated patients and functional class improved significantly with only 6 patients remaining in NYHA class 2. There was no early or late operative mortality and no patient required re-operation for DCRV during a median follow-up of 8 years. Contemporary adult DCRV patients have good survival prospects and low long-term morbidity. Despite occasionally presenting with considerable intraventricular gradients we could not identify any case of sudden death in our unoperated adult sub-population. Although asymptomatic adults may be encountered even with severe obstruction, symptom development is common during adult life. Cardiac surgery in this cohort is inherently low risk and offers good long-term haemodynamic and functional results justifying early intervention in consideration of the progressive nature of this rare congenital lesion. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Two chamber reaction furnace

    DOEpatents

    Blaugher, R.D.

    1998-05-05

    A vertical two chamber reaction furnace is described. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 C and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

  20. Two chamber reaction furnace

    DOEpatents

    Blaugher, Richard D.

    1998-05-05

    A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

  1. Neutron Detection via Bubble Chambers

    SciTech Connect

    Jordan, David V.; Ely, James H.; Peurrung, Anthony J.; Bond, Leonard J.; Collar, J. I.; Flake, Matthew; Knopf, Michael A.; Pitts, W. K.; Shaver, Mark W.; Sonnenschein, Andrew; Smart, John E.; Todd, Lindsay C.

    2005-10-06

    The results of a Pacific Northwest National Laboratory (PNNL) exploratory research project investigating the feasibility of fast neutron detection using a suitably prepared and operated, pressure-cycled bubble chamber are described. The research was conducted along two parallel paths. Experiments with a slow pressure-release Halon chamber at the Enrico Fermi Institute at the University of Chicago showed clear bubble nucleation sensitivity to an AmBe neutron source and insensitivity to the 662 keV gammas from a 137Cs source. Bubble formation was documented via high-speed (1000 frames/sec) photography, and the acoustic signature of bubble formation was detected using a piezo-electric transducer element mounted on the base of the chamber. The chamber’s neutron sensitivity as a function of working fluid temperature was mapped out. The second research path consisted of the design, fabrication, and testing of a fast pressure-release Freon-134a chamber at PNNL. The project concluded with successful demonstrations of the PNNL chamber’s AmBe neutron source sensitivity and 137Cs gamma insensitivity. The source response tests of the PNNL chamber were documented with high-speed photography.

  2. Impact of aftertreatment devices on primary emissions and secondary organic aerosol formation potential from in-use diesel vehicles: results from smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Chirico, R.; Decarlo, P. F.; Heringa, M. F.; Tritscher, T.; Richter, R.; Prevot, A. S. H.; Dommen, J.; Weingartner, E.; Wehrle, G.; Gysel, M.; Laborde, M.; Baltensperger, U.

    2010-06-01

    Diesel particulate matter (DPM) is a significant source of aerosol in urban areas and has been linked to adverse health effects. Although newer European directives have introduced increasingly stringent standards for primary PM emissions, gaseous organics emitted from diesel cars can still lead to large amounts of secondary organic aerosol (SOA) in the atmosphere. Here we present results from smog chamber investigations characterizing the primary organic aerosol (POA) and the corresponding SOA formation at atmospherically relevant concentrations for three in-use diesel vehicles with different exhaust aftertreatment systems. One vehicle lacked exhaust aftertreatment devices, one vehicle was equipped with a diesel oxidation catalyst (DOC) and the final vehicle used both a DOC and diesel particulate filter (DPF). The experiments presented here were obtained from the vehicles at conditions representative of idle mode, and for one car in addition at a speed of 60 km/h. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to measure the organic aerosol (OA) concentration and to obtain information on the chemical composition. For the conditions explored in this paper, primary aerosols from vehicles without a particulate filter consisted mainly of black carbon (BC) with a low fraction of organic matter (OM, OM/BC<0.5), while the subsequent aging by photooxidation resulted in a consistent production of SOA only for the vehicles without a DOC and with a deactivated DOC. After 5 h of aging ~80% of the total organic aerosol was on average secondary and the estimated "emission factor" for SOA was 0.23-0.56 g/kg fuel burned. In presence of both a DOC and a DPF, primary particles with a mobility diameter above 5 nm were 300±19 cm-3, and only 0.01 g SOA per kg fuel burned was produced within 5 h after lights on. The mass spectra indicate that POA was mostly a non-oxidized OA with an oxygen to carbon atomic ratio (O/C) ranging from 0.097 to 0

  3. Impact of aftertreatment devices on primary emissions and secondary organic aerosol formation potential from in-use diesel vehicles: results from smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Chirico, R.; Decarlo, P. F.; Heringa, M. F.; Tritscher, T.; Richter, R.; Prévôt, A. S. H.; Dommen, J.; Weingartner, E.; Wehrle, G.; Gysel, M.; Laborde, M.; Baltensperger, U.

    2010-12-01

    Diesel particulate matter (DPM) is a significant source of aerosol in urban areas and has been linked to adverse health effects. Although newer European directives have introduced increasingly stringent standards for primary PM emissions, gaseous organics emitted from diesel cars can still lead to large amounts of secondary organic aerosol (SOA) in the atmosphere. Here we present results from smog chamber investigations characterizing the primary organic aerosol (POA) and the corresponding SOA formation at atmospherically relevant concentrations for three in-use diesel vehicles with different exhaust aftertreatment systems. One vehicle lacked exhaust aftertreatment devices, one vehicle was equipped with a diesel oxidation catalyst (DOC) and the third vehicle used both a DOC and diesel particulate filter (DPF). The experiments presented here were obtained from the vehicles at conditions representative of idle mode, and for one car in addition at a speed of 60 km/h. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was used to measure the organic aerosol (OA) concentration and to obtain information on the chemical composition. For the conditions explored in this paper, primary aerosols from vehicles without a particulate filter consisted mainly of black carbon (BC) with a low fraction of organic matter (OM, OM/BC < 0.5), while the subsequent aging by photooxidation resulted in a consistent production of SOA only for the vehicles without a DOC and with a deactivated DOC. After 5 h of aging ~80% of the total organic aerosol was on average secondary and the estimated "emission factor" for SOA was 0.23-0.56 g/kg fuel burned. In presence of both a DOC and a DPF, only 0.01 g SOA per kg fuel burned was produced within 5 h after lights on. The mass spectra indicate that POA was mostly a non-oxidized OA with an oxygen to carbon atomic ratio (O/C) ranging from 0.10 to 0.19. Five hours of oxidation led to a more oxidized OA with an O/C range of 0

  4. Hydrostatic Hyperbaric Chamber Ventilation System

    NASA Technical Reports Server (NTRS)

    Sargusingh, Miriam M.

    2011-01-01

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

  5. Performance of two passive warming chamber designs in a northern Mongolian steppe

    NASA Astrophysics Data System (ADS)

    Sharkhuu, A.; Plante, A. F.; Casper, B.; Helliker, B. R.; Liancourt, P.; Petraitis, P.

    2009-12-01

    The recent study in the Lake Hövsgöl region of northern Mongolia has shown that mean annual air temperature has increased by 1.8 °C over the last 40 years, greater than global average temperature increases. The observed climate change will have a significant impact on the ecosystem of this region, and thus simulating the warming and its impacts on the ecosystem are essential. Passive open-top chambers (OTC) have been proposed as a method to simulate temperature change and used in ITEX (International Tundra Experiment) sites (Marion et al., 1997; GCB 3(S1)20-32). The OTCs cause air temperature to increase by 1.2-2.0 °C, mostly during the day by decreasing convective cooling. However, actual climate warming will be caused mainly through increased long-wave radiation. An alternative design is an open-side chamber (OSC) which is supposed to increase long-wave radiation and thus to increase air temperature (Germino and Demshar, 2008; ESA Annual Meeting). The objective of this study was to compare the performance of the two passive warming chamber designs being used in an experiment on climate change impacts in northern Mongolia. The performance of the chambers was assessed on the basis of degree and timing of warming of air and surface soil, as well as the degree of alteration in soil moisture. The experimental site is located in Dalbay Valley, part of the Lake Hövsgöl International Long-Term Ecological Research (ILTER) site on the eastern shore of the lake in northern Mongolia (51° 01.405' N 100° 45.600' E; 1670 m elevation). Eight plots, with OTC, OSC and a non-warmed control were installed on the south facing slope of the valley. Plots were 4 × 9 m and placed randomly on the landscape approximately 40 m apart. Aboveground air temperature and belowground (10 cm) soil temperature were recorded for each treatment (control, OTC and OSC) in four out of eight plots by HOBO dataloggers. Daily measurements of surface (0-5 cm) soil temperature and volumetric moisture

  6. Target chambers for gammashpere

    SciTech Connect

    Carpenter, M.P.; Falout, J.W.; Nardi, B.G.

    1995-08-01

    One of our responsibilities for Gammasphere, was designing and constructing two target chambers and associated beamlines to be used with the spectrometer. The first chamber was used with the early implementation phase of Gammasphere, and consisted of two spun-Al hemispheres welded together giving a wall thickness of 0.063 inches and a diameter of 12 inches.

  7. A soundproof pressure chamber.

    PubMed

    Kitahara, M; Kodama, A; Ozawa, H; Inoue, S

    1994-01-01

    For neurotological research we designed a soundproof pressure chamber in which pressure can be adjusted +/- 1000 mmH2O at the rate of less than 100 mmH2O per second. Noise in the chamber can be maintained under 30-35 dB while pressure is kept at a given level.

  8. Static diffusion cloud chambers

    NASA Technical Reports Server (NTRS)

    Ayers, G.

    1981-01-01

    The chamber geometry and optical arrangement are described. The supersaturation range is given and consists of readings taken at five fixed points: 0.25%, 0.5%, 0.75%, 1.0%, and 1.25%. The detection system is described including light source, cameras, and photocell detectors. The temperature control and the calibration of the chamber are discussed.

  9. High resolution drift chambers

    SciTech Connect

    Va'vra, J.

    1985-07-01

    High precision drift chambers capable of achieving less than or equal to 50 ..mu..m 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.

  10. The Mobile Chamber

    NASA Technical Reports Server (NTRS)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

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

  11. Note: Small anaerobic chamber for optical spectroscopy

    SciTech Connect

    Chauvet, Adrien A. P. Chergui, Majed; Agarwal, Rachna; Cramer, William A.

    2015-10-15

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

  12. Multispecimen dual-beam irradiation damage chamber

    SciTech Connect

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

    1980-06-01

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

  13. Aging in large CDF tracking chambers

    SciTech Connect

    M. Binkley et al.

    2001-03-19

    The experience of the Collider Detector at Fermilab (CDF) with aging in the large axial drift chamber responsible for tracking in the central region is presented. Premature aging in the Run 1 chamber was observed after only 0.02 C/cm. After cleaning much of the gas system and making modifications to reduce aerosols from the alcohol bubbler, the observed aging rate fell dramatically in test chambers. Considerable effort has been made to better understand the factors that affect aging since the replacement chamber for Run 2 will accumulate about 1.0 C/cm. Current test chambers using the full CDF gas system show aging rates of less than 5%/C/cm.

  14. Note: Small anaerobic chamber for optical spectroscopy.

    PubMed

    Chauvet, Adrien A P; Agarwal, Rachna; Cramer, William A; Chergui, Majed

    2015-10-01

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

  15. A three-dimensional tomographic velocity model above Mid Atlantic magma chamber from simulated seafloor multi-channel seismic refraction experiment

    NASA Astrophysics Data System (ADS)

    Arnulf, A. F.; Harding, A. J.; Kent, G.; Singh, S. C.

    2009-12-01

    With multi-channel seismic (MCS) data recorded on the sea surface, refraction arrivals from the upper crust typically arrive as secondary arrivals after the seafloor reflection, and therefore they do not contain any information on near seafloor velocity. Here we use a Synthetic On Bottom Experiment (SOBE) method to downward continue both shots and receivers to a depth close to the seafloor, which causes refraction arrivals from the upper crust to become first arrivals that can be followed to close to zero source receiver offsets, providing information about near surface velocity. Moreover, the high density of shots and receivers in MCS-based travel-time tomography produces a multiplicity of ray paths never reached by classical travel time tomography methods based on OBS datasets, and hence providing a high-resolution velocity of the sub-surface. We have applied this new technique to the MCS data from the SISMOMAR 3D seismic reflection survey carried out in 2005 over the Lucky Strike Segment of the Mid-Atlantic Ridge. The survey area was 18.55 km by 3.8 km, with a shot spacing of 37.5 m, receiver spacing of 12.5 m and the line spacing of 100 m. It has been the first segment of the MAR to be shown to have a quasi-steady state magma chamber, and we are creating now a high resolution velocity model to investigate in detail the links between magmatism, hydrothermal circulation and faulting in this segment. First, the data was downward continued to 1.0-1.7 km below the sea surface. Then a highly efficient algorithm was used to pick ~800,000 travel times. Because of the the high density of ray paths (up to 7 million), the first arrivals of every fifth shots was picked. To control the picking consistency along a line, picks from the preceding shot was used to guide the current one. Travel time residuals, ~10 ms, and chi-squared of the final 2D model testify to excellent picking accuracy. A 3D velocity cube was then interpolated using ten equi-spaced 2D velocity models

  16. New cloud chamber experiments on the heterogeneous ice nucleation ability of oxalic acid in the deposition nucleation and immersion freezing modes

    NASA Astrophysics Data System (ADS)

    Moehler, O.; Wagner, R.; Saathoff, H.; Schnaiter, M.; Leisner, T.

    2010-12-01

    Dicarboxylic acids are ubiquitous components of the water-soluble organic fraction of the tropospheric aerosol. Their contribution to the total particulate organic carbon typically ranges from 1 - 3 wt% in urban and semi-urban areas to up to 10 wt% in remote marine atmospheres [1,2]. Oxalic acid, malonic acid, and succinic acid are usually the most abundant species, partly comprising more than 80% of the total diacid mass concentrations [3]. Several recent studies have addressed the ice nucleation potential of solid low-molecular weight dicarboxylic acids. On the one hand, the dicarboxylic acids can act as deposition mode ice nuclei provided that they are directly exposed to an ice supersaturated environment, e.g. in form of a coating layer that was formed by physical and chemical processing on prevalent particulates such as mineral dust and soot. At typical tropospheric relative humidities, diacids of low water solubility like oxalic and succinic acid may, on the other hand, also be present as solids that are immersed in aqueous inorganic and/or organic solution droplets [4,5]. These embedded crystals can act as ice nuclei in the immersion mode. Here we present new results from recent experiments at the aerosol and cloud chamber facility of the Karlsruhe Institute of Technology. The ice nucleation ability of aqueous and crystalline oxalic acid aerosol particles was investigated at expansion cooling conditions in the temperature range between 244 and 228 K [6]. Oxalic acid dihydrate particles with diameters between 0.03 to 0.8 μm, that were either formed by nucleation from a gaseous oxalic acid/air mixture or by rapid crystallisation of highly supersaturated aqueous oxalic acid solution droplets, showed a high deposition mode ice activity at temperatures around 244 K. The ice onset humidity was below 110 % with respect to ice, and the ice-active fraction of the aerosol population was in the range from 0.1 to 22%. In contrast, oxalic acid dihydrate particles

  17. Modelling winter organic aerosol at the European scale with CAMx: evaluation and source apportionment with a VBS parameterization based on novel wood burning smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Ciarelli, Giancarlo; Aksoyoglu, Sebnem; El Haddad, Imad; Bruns, Emily A.; Crippa, Monica; Poulain, Laurent; Äijälä, Mikko; Carbone, Samara; Freney, Evelyn; O'Dowd, Colin; Baltensperger, Urs; Prévôt, André S. H.

    2017-06-01

    We evaluated a modified VBS (volatility basis set) scheme to treat biomass-burning-like organic aerosol (BBOA) implemented in CAMx (Comprehensive Air Quality Model with extensions). The updated scheme was parameterized with novel wood combustion smog chamber experiments using a hybrid VBS framework which accounts for a mixture of wood burning organic aerosol precursors and their further functionalization and fragmentation in the atmosphere. The new scheme was evaluated for one of the winter EMEP intensive campaigns (February-March 2009) against aerosol mass spectrometer (AMS) measurements performed at 11 sites in Europe. We found a considerable improvement for the modelled organic aerosol (OA) mass compared to our previous model application with the mean fractional bias (MFB) reduced from -61 to -29 %. We performed model-based source apportionment studies and compared results against positive matrix factorization (PMF) analysis performed on OA AMS data. Both model and observations suggest that OA was mainly of secondary origin at almost all sites. Modelled secondary organic aerosol (SOA) contributions to total OA varied from 32 to 88 % (with an average contribution of 62 %) and absolute concentrations were generally under-predicted. Modelled primary hydrocarbon-like organic aerosol (HOA) and primary biomass-burning-like aerosol (BBPOA) fractions contributed to a lesser extent (HOA from 3 to 30 %, and BBPOA from 1 to 39 %) with average contributions of 13 and 25 %, respectively. Modelled BBPOA fractions were found to represent 12 to 64 % of the total residential-heating-related OA, with increasing contributions at stations located in the northern part of the domain. Source apportionment studies were performed to assess the contribution of residential and non-residential combustion precursors to the total SOA. Non-residential combustion and road transportation sector contributed about 30-40 % to SOA formation (with increasing contributions at urban and near

  18. The crop growth research chamber

    NASA Technical Reports Server (NTRS)

    Wagenbach, Kimberly

    1993-01-01

    The Crop Growth Research Chamber (CGRC) has been defined by CELSS principle investigators and science advisory panels as a necessary ground-based tool in the development of a regenerative life support system. The focus of CGRC research will be on the biomass production component of the CELSS system. The ground-based Crop Growth Research Chamber is for the study of plant growth and development under stringently controlled environments isolated from the external environment. The chamber has importance in three areas of CELSS activities: (1) crop research; (2) system control and integration, and (3) flight hardware design and experimentation. The laboratory size of the CGRC will be small enough to allow duplication of the unit, the conducting of controlled experiments, and replication of experiments, but large enough to provide information representative of larger plant communities. Experiments will focus on plant growth in a wide variety of environments and the effects of those environments on plant production of food, water, oxygen, toxins, and microbes. To study these effects in a closed system, tight control of the environment is necessary.

  19. Hydrostatic Hyperbaric Chamber Ventilation System

    NASA Technical Reports Server (NTRS)

    Sarguisingh, Miriam J.

    2012-01-01

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

  20. Oxygen isotope ratios (18O/16O) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy I: Insight from a climate chamber experiment

    NASA Astrophysics Data System (ADS)

    Zech, Michael; Mayr, Christoph; Tuthorn, Mario; Leiber-Sauheitl, Katharina; Glaser, Bruno

    2014-02-01

    The oxygen isotopic composition of cellulose is a valuable proxy in paleoclimate research. However, its application to sedimentary archives is challenging due to extraction and purification of cellulose. Here we present compound-specific δ18O results of hemicellulose-derived sugar biomarkers determined using gas chromatography-pyrolysis-isotope ratio mass spectrometry, which is a method that overcomes the above-mentioned analytical challenges. The biomarkers were extracted from stem material of different plants (Eucalyptus globulus, Vicia faba and Brassica oleracea) grown in climate chamber experiments under different climatic conditions. The δ18O values of arabinose and xylose range from 31.4‰ to 45.9‰ and from 28.7‰ to 40.8‰, respectively, and correlate highly significantly with each other (R = 0.91, p < 0.001). Furthermore, δ18Ohemicellulose (mean of arabinose and xylose) correlate highly significantly with δ18Oleaf water (R = 0.66, p < 0.001) and significantly with modeled δ18Ocellulose (R = 0.42, p < 0.038), as well as with relative air humidity (R = -0.79, p < 0.001) and temperature (R = -0.66, p < 0.001). These findings confirm that the hemicellulose-derived sugar biomarkers, like cellulose, reflect the oxygen isotopic composition of plant source water altered by climatically controlled evapotranspirative 18O enrichment of leaf water. While relative air humidity controls most rigorously the evapotranspirative 18O enrichment, the direct temperature effect is less important. However, temperature can indirectly exert influence via plant physiological reactions, namely by influencing the transpiration rate which affects δ18Oleaf water due to the Péclet effect. In a companion paper (Tuthorn et al., this issue) we demonstrate the applicability of the hemicellulose-derived sugar biomarker δ18O method to soils and provide evidence from a climate transect study confirming that relative air humidity exerts the dominant control on evapotranspirative 18O

  1. Control of nitrification/denitrification in an onsite two-chamber intermittently aerated membrane bioreactor with alkalinity and carbon addition: Model and experiment.

    PubMed

    Perera, Mahamalage Kusumitha; Englehardt, James D; Tchobanoglous, George; Shamskhorzani, Reza

    2017-02-20

    Denitrifying membrane bioreactors (MBRs) are being found useful in water reuse treatment systems, including net-zero water (nearly closed-loop), non-reverse osmosis-based, direct potable reuse (DPR) systems. In such systems nitrogen may need to be controlled in the MBR to meet the nitrate drinking water standard in the finished water. To achieve efficient nitrification and denitrification, the addition of alkalinity and external carbon may be required, and control of the carbon feed rate is then important. In this work, an onsite, two-chamber aerobic nitrifying/denitrifying MBR, representing one unit process of a net-zero water, non-reverse osmosis-based DPR system, was modeled as a basis for control of the MBR internal recycling rate, aeration rate, and external carbon feed rate. Specifically, a modification of the activated sludge model ASM2dSMP was modified further to represent the rate of recycling between separate aerobic and anoxic chambers, rates of carbon and alkalinity feed, and variable aeration schedule, and was demonstrated versus field data. The optimal aeration pattern for the modeled reactor configuration and influent matrix was found to be 30 min of aeration in a 2 h cycle (104 m(3) air/d per 1 m(3)/d average influent), to ultimately meet the nitrate drinking water standard. Optimal recycling ratios (inter-chamber flow to average daily flow) were found to be 1.5 and 3 during rest and mixing periods, respectively. The model can be used to optimize aeration pattern and recycling ratio in such MBRs, with slight modifications to reflect reactor configuration, influent matrix, and target nitrogen species concentrations, though some recalibration may be required.

  2. 45. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION DDD), ...

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

    45. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION DDD), VIEW LOOKING EAST. LEAD ENCLOSED PIPING IS DRAIN FROM BOILER CHAMBER No. 1 - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  3. The LIFE Dynamic Chamber System

    NASA Astrophysics Data System (ADS)

    Rhodes, Mark; Kane, Jave; Latkowski, Jeffery; Cook, Andrew; Divol, Laurent; Loosmore, Gwendolen; Scott, Howard; Scullard, Christian; Tabak, Max; Wilks, Scott; Moses, Gregory; Heltemes, Thad; Sacks, Ryan; Pantano, Carlos; Kramer, Richard

    2011-10-01

    Dry-wall IFE designs such as LIFE utilize Xe fill gas to protect the target chamber first wall from x-ray heating and ionic debris. A key question is how cool, settled and clean the Xe must be to permit beam propagation and target transport, and how to reach this state at a 10+ Hz shot repetition rate. Xe is at low density in the target chamber, and purified Xe is reinjected at higher density and lower temperature into the larger outer chamber. Maintenance of this density difference due to blast waves generated by implosion of the target capsules is being assessed with HYDRA and 3D VTF, and possible validation experiments are being investigated. Detailed gas response near the wall is being studied using 3D Miranda. A laboratory-scale theta pinch experiment will study cooling and beam propagation in Xe. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  4. APS Storage Ring vacuum chamber fabrication

    SciTech Connect

    Goeppner, G.A.

    1990-01-01

    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.

  5. Simple cloud chambers using gel ice packs

    NASA Astrophysics Data System (ADS)

    Kamata, Masahiro; Kubota, Miki

    2012-07-01

    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 ice or liquid nitrogen. The gel can be frozen in normal domestic freezers, and can be used repeatedly by re-freezing. The tracks of alpha-ray particles can be observed continuously for about 20 min, and the operation is simple and easy.

  6. Acoustic-Levitation Chamber

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  7. The Mars Chamber

    NASA Image and Video Library

    The Mars chamber is a box about the size of a refrigerator that re-creates the temperatures, pressures, and atmosphere of the Martian surface, essentially creating a Mars environment on Earth! Scie...

  8. Sleeve reaction chamber system

    SciTech Connect

    Northrup, M Allen; Beeman, Barton V; Benett, William J; Hadley, Dean R; Landre, Phoebe; Lehew, Stacy L; Krulevitch, Peter A

    2009-08-25

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

  9. Formaldehyde vapor produced from hexamethylenetetramine and pesticide: Simultaneous monitoring of formaldehyde and ozone in chamber experiments by flow-based hybrid micro-gas analyzer.

    PubMed

    Yanaga, Akira; Hozumi, Naruto; Ohira, Shin-Ichi; Hasegawa, Asako; Toda, Kei

    2016-02-01

    Simultaneous analysis of HCHO and O3 was performed by the developed flow analysis system to prove that HCHO vapor is produced from solid pesticide in the presence of O3. HCHO is produced in many ways, including as primary emissions from fuel combustion and in secondary production from anthropogenic and biogenic volatile organic compounds by photochemical reactions. In this work, HCHO production from pesticides was investigated for the first time. Commonly pesticide contains surfactant such as hexamethylenetetramine (HMT), which is a heterocyclic compound formed from six molecules of HCHO and four molecules of NH3. HMT can react with gaseous oxidants such as ozone (O3) to produce HCHO. In the present study, a flow analysis system was developed for simultaneous analysis of HCHO and O3, and this system was used to determine if solid pesticides produced HCHO vapor in the presence of O3. HMT or the pesticide jimandaisen, which contains mancozeb as the active ingradient and HMT as a stabilizer was placed at the bottom of a 20-L stainless steel chamber. Air in the chamber was monitored using the developed flow system. Analyte gases were collected into an absorbing solution by a honeycomb-patterned microchannel scrubber that was previously developed for a micro gas analysis system (μGAS). Subsequently, indigotrisulfonate, a blue dye, was added to the absorbing solution to detect O3, which discolored the solution. HCHO was detected after mixing with the Hantzsch reaction reagent. Both gases could be detected at concentrations ranging from parts per billion by volume (ppbv) to 1000 ppbv with good linearity. Both HMT and jimandaisen emitted large amount of HCHO in the presence of O3.

  10. First in vitro and in vivo experiences with Stay-Safe Balance, a pH-neutral solution in a dual-chambered bag.

    PubMed

    Lage, C; Pischetsrieder, M; Aufricht, C; Jörres, A; Schilling, H; Passlick-Deetjen, J

    2000-01-01

    In addition to low pH and high osmolarity, glucose degradation products (GDPs) are considered to play a major role in the bioincompatibility of peritoneal dialysis fluids (PDFs). The formation of GDPs can be reduced by separating the glucose component of the solution (kept at very low pH) from the lactate component of the solution (kept at alkaline pH) during sterilization and storage. This development has been achieved by the use of a dual-chambered bag. Immediately before infusion, the seam between the two chambers is opened, and the contents are mixed. The result is a fluid with a more physiologic pH in the range 6.8 - 7.4. Concentrations of 3-deoxyglucosone (3-DG), methylglyoxal (MG), acetaldehyde (AA), and formaldehyde (FA) in Stay-Safe Balance (Fresenius Medical Care, Bad Homburg, Germany) were remarkably reduced when compared to conventional PD solution [conventional PDF (1.5% glucose): 172 micromol/L, 6 microLmol/L, 152 micromol/L, and 7 micromol/L respectively; Stay-Safe Balance (1.5% glucose): 42 micromolL, < 1 micromol/L, < 2 micromol/L, and < 3 micromol/L respectively; conventional PDF (4.25% glucose): 324 micromol/L, 10 micromol/L, 182 micromol/L, and 13 micromol/L respectively; Stay-Safe Balance (4.25% glucose): 60 micromol/L, < 1 micromol/L, < 2 micromol/L, and < 3 micromol/L respectively). Human peritoneal mesothelial cells (HPMCs) were exposed to a control solution, a conventional PDF [CAPD 2, 1.5% glucose (Fresenius Medical Care, Bad Homburg, Germany)], and Stay-Safe Balance, either in a co-incubation model (24-hour PDF exposure) or in a pre-incubation model (30-min PDF exposure), followed by 24-hour recovery in culture medium. Interleukin-1beta (IL-1beta)-stimulated (1 ng/mL) IL-6 secretion from HPMCs was assessed by ELISA. Exposure of HPMCs to conventional PDF resulted in a significant reduction in IL-6 release, which was fully restored following exposure to Stay-Safe Balance. In addition to the short-term investigations, long-term in vitro

  11. Thrust chamber life prediction

    NASA Technical Reports Server (NTRS)

    Kasper, H. J.

    1985-01-01

    The reusable life of the Space Shuttle main engine (SSME) is influenced by the cyclic life of the regeneratively liquid cooled main combustion chamber (MCC). During an operational duty cycle the MCC liner is subjected to a large transient thermal gradient that imparts a high thermal cyclic strain to the liner hot gas wall. Life predictions of such chambers have usually been based on low cycle fatigue (LCF) evaluations. Hot-fire testing, however, has shown significant mid-channel wall deformation and thinning during accrued cyclic testing. This phenomenon is termed cyclic creep and appears to be significantly accelerated at elevated temperatures. An analytical method that models the cyclic creep phenomenon and its application to thrust chamber life prediction is presented. The chamber finite element geometry is updated periodically to account for accrued wall thinning and distortion. Failure is based on the tensile instability failure criterion. Cyclic life results for several chamber life enhancing coolant channel designs are compared to the typically used LCF analysis that neglects cyclic creep. The results show that the usable cyclic creep life is approximately 30 to 50% of the commonly used LCF life.

  12. Improved Rhenium Thrust Chambers

    NASA Technical Reports Server (NTRS)

    O'Dell, John Scott

    2015-01-01

    Radiation-cooled bipropellant thrust chambers are being considered for ascent/ descent engines and reaction control systems on various NASA missions and spacecraft, such as the Mars Sample Return and Orion Multi-Purpose Crew Vehicle (MPCV). Currently, iridium (Ir)-lined rhenium (Re) combustion chambers are the state of the art for in-space engines. NASA's Advanced Materials Bipropellant Rocket (AMBR) engine, a 150-lbf Ir-Re chamber produced by Plasma Processes and Aerojet Rocketdyne, recently set a hydrazine specific impulse record of 333.5 seconds. To withstand the high loads during terrestrial launch, Re chambers with improved mechanical properties are needed. Recent electrochemical forming (EL-Form"TM") results have shown considerable promise for improving Re's mechanical properties by producing a multilayered deposit composed of a tailored microstructure (i.e., Engineered Re). The Engineered Re processing techniques were optimized, and detailed characterization and mechanical properties tests were performed. The most promising techniques were selected and used to produce an Engineered Re AMBR-sized combustion chamber for testing at Aerojet Rocketdyne.

  13. The DELPHI time projection chamber

    SciTech Connect

    Brand, C.; Cairanti, G.; Charpentier, P.; Clara, M.P.; Delikaris, D.; Foeth, H.; Heck, B.W.; Hilke, H.J.; Sulkowski, K.; Aubret, C.

    1989-02-01

    The central tracking device of the DELPHI Experiment at LEP is a Time Projection Chamber (TPC) with an active volume of 2 x 1.34m in length and 2.22m in diameter. Since spring 1988 the TPC has undergone extensive tests in a cosmic ray set-up. It will be installed in the LEP tunnel by early 1989. This report covers the construction, the read-out electronics and the contribution of the TPC to the DELPHI trigger. Emphasis is given to novelties which are not used in similar detectors.

  14. Antipollution combustion chamber

    SciTech Connect

    Caruel, J.E.; Gastebois, P.M.

    1981-01-27

    The invention concerns a combustion chamber for turbojet engines. The combustion chamber is of the annular type and consists of two coaxial flame tubes opening into a common dilution and mixing zone. The inner tube is designed for low operating ratings of the engine, the outer tube for high ratings. Air is injected as far upstream as possible into the dilution zone, to enhance the homogenization of the gaseous flow issuing from the two tubes prior to their passage into the turbine and to assure the optimum radial distribution of temperatures. The combustion chamber according to the invention finds application in a particularly advantageous manner in turbojet engines used in aircraft propulsion because of the reduced emission of pollutants it affords.

  15. Growth responses, biomass partitioning, and nitrogen isotopes of prairie legumes in response to elevated temperature and varying nitrogen source in a growth chamber experiment.

    PubMed

    Whittington, Heather R; Deede, Laura; Powers, Jennifer S

    2012-05-01

    Because legumes can add nitrogen (N) to ecosystems through symbiotic fixation, they play important roles in many plant communities, such as prairies and grasslands. However, very little research has examined the effect of projected climate change on legume growth and function. Our goal was to study the effects of temperature on growth, nodulation, and N chemistry of prairie legumes and determine whether these effects are mediated by source of N. We grew seedlings of Amorpha canescens, Dalea purpurea, Lespedeza capitata, and Lupinus perennis at 25/20°C (day/night) or 28/23°C with and without rhizobia and mineral N in controlled-environment growth chambers. Biomass, leaf area, nodule number and mass, and shoot N concentration and δ(15)N values were measured after 12 wk of growth. Both temperature and N-source affected responses in a species-specific manner. Lespedeza showed increased growth and higher shoot N content at 28°C. Lupinus showed decreases in nodulation and lower shoot N concentration at 28°C. The effect of temperature on shoot N concentration occurred only in individuals whose sole N source was N(2)-fixation, but there was no effect of temperature on δ(15)N values in these plants. Elevated temperature enhanced seedling growth of some species, while inhibiting nodulation in another. Temperature-induced shifts in legume composition or nitrogen dynamics may be another potential mechanism through which climate change affects unmanaged ecosystems.

  16. Filament wound rocket motor chambers

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The design, analysis, fabrication and testing of a Kevlar-49/HBRF-55A filament wound chamber is reported. The chamber was fabricated and successfully tested to 80% of the design burst pressure. Results of the data reduction and analysis from the hydrotest indicate that the chamber design and fabrication techniques used for the chamber were adequate and the chamber should perform adequately in a static test.

  17. Automated soil gas monitoring chamber

    DOEpatents

    Edwards, Nelson T.; Riggs, Jeffery S.

    2003-07-29

    A chamber for trapping soil gases as they evolve from the soil without disturbance to the soil and to the natural microclimate within the chamber has been invented. The chamber opens between measurements and therefore does not alter the metabolic processes that influence soil gas efflux rates. A multiple chamber system provides for repetitive multi-point sampling, undisturbed metabolic soil processes between sampling, and an essentially airtight sampling chamber operating at ambient pressure.

  18. Electrostatic Levitator Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Optical ports ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (beam passes through the window at left), positioning lasers (one port is at center), and lamps to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  19. Smog chamber experiments to investigate Henry's law constants of glyoxal using different seed aerosols as well as imidazole formation in the presence of ammonia

    NASA Astrophysics Data System (ADS)

    Jakob, Ronit

    2015-04-01

    Aerosols play an important role in the chemistry and physics of the atmosphere. Hence, they have a direct as well as an indirect impact on the earth's climate. Depending on their formation, one distinguishes between primary and secondary aerosols[1]. Important groups within the secondary aerosols are the secondary organic aerosols (SOAs). In order to improve predictions about these impacts on the earth's climate the existing models need to be optimized, because they still underestimate SOA formation[2]. Glyoxal, the smallest α-dicarbonyl, not only acts as a tracer for SOA formation but also as a direct contributor to SOA. Because glyoxal has such a high vapour pressure, it was common knowledge that it does not take part in gas-particle partitioning and therefore has no impact on direct SOA formation. However, the Henry's law constant for glyoxal is surprisingly high. This has been explained by the hydration of the aldehyde groups, which means that a species with a lower vapour pressure is produced. Therefore the distribution of glyoxal between gas- and particle phase is atmospherically relevant and the direct contribution of glyoxal to SOA can no longer be neglected[3]. Besides this particulate glyoxal is able to undergo heterogeneous chemistry with gaseous ammonia to form imidazoles. This plays an important role for regions with aerosols exhibiting alkaline pH values for example from lifestock or soil dust because imidazoles as nitrogen containing compounds change the optical properties of aerosols[4]. A high salt concentration present in chamber seed aerosols leads to an enhanced glyoxal uptake into the particle. This effect is called "salting-in". The salting effect depends on the composition of the seed aerosol as well as the soluble compound. For very polar compounds, like glyoxal, a "salting-in" is observed[3]. Glyoxal particle formation during a smog chamber campaign at Paul-Scherrer-Institut (PSI) in Switzerland was examined using different seed aerosols

  20. Optimization of a closed-loop gas system for the operation of Resistive Plate Chambers at the Large Hadron Collider experiments

    NASA Astrophysics Data System (ADS)

    Capeans, M.; Glushkov, I.; Guida, R.; Hahn, F.; Haider, S.

    2012-01-01

    Resistive Plate Chambers (RPCs), thanks to their fast time resolution (˜1 ns), suitable space resolution (˜1 cm) and low production cost (˜50 €/m2), are widely employed for the muon trigger systems at the Large Hadron Collider (LHC). Their large detector volume (they cover a surface of about 4000 m2 equivalent to 16 m3 of gas volume both in ATLAS and CMS) and the use of a relatively expensive Freon-based gas mixture make a closed-loop gas circulation unavoidable. It has been observed that the return gas of RPCs operated in conditions similar to the difficult experimental background foreseen at LHC contains a large amount of impurities potentially dangerous for long-term operation. Several gas-cleaning agents are currently in use in order to avoid accumulation of impurities in the closed-loop circuits. We present the results of a systematic study characterizing each of these cleaning agents. During the test, several RPCs were operated at the CERN Gamma Irradiation Facility (GIF) in a high radiation environment in order to observe the production of typical impurities: mainly fluoride ions, molecules of the Freon group and hydrocarbons. The polluted return gas was sent to several cartridges, each containing a different cleaning agent. The effectiveness of each material was studied using gas chromatography and mass-spectrometry techniques. Results of this test have revealed an optimized configuration of filters that is now under long-term validation.Gas optimization studies are complemented with a finite element simulation of gas flow distribution in the RPCs, aiming at its eventual optimization in terms of distribution and flow rate.

  1. Improved wire chamber

    DOEpatents

    Atac, M.

    1987-05-12

    An improved gas mixture for use with proportional counter devices, such as Geiger-Mueller tubes and drift chambers. The improved gas mixture provides a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor. 2 figs.

  2. Parmitano with MDCA chamber

    NASA Image and Video Library

    2013-07-24

    ISS036-E-025481 (24 July 2013) --- European Space Agency astronaut Luca Parmitano, Expedition 36 flight engineer, works on the Multi-User Droplet Combustion Apparatus (MDCA) Chamber Insert Assembly (CIA) at a maintenance work station in the Harmony node of the International Space Station.

  3. Metabolic simulation chamber

    NASA Technical Reports Server (NTRS)

    Bartlett, R. G.; Hendricks, C. M.

    1972-01-01

    Metabolic simulation combustion chamber was developed as subsystem for breathing metabolic simulator. Entire system is used for evaluation of life support and resuscitation equipment. Metabolism subsystem simulates a human by consuming oxygen and producing carbon dioxide. Basic function is to simulate human metabolic range from rest to hard work.

  4. Flame-Test Chamber

    NASA Technical Reports Server (NTRS)

    Bjorklund, R. A.

    1984-01-01

    Experimental chamber provides controlled environment for observation and measurement of flames propagating in expanding plume of flammable air/fuel mixture under atmospheric conditions. Designed to evaluate quenching capability of screen-type flame arresters in atmospheric vents of fuel cargo tanks aboard marine cargo vessels.

  5. Liquid Wall Chambers

    SciTech Connect

    Meier, W R

    2011-02-24

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

  6. Multi-chamber deposition system

    DOEpatents

    Jacobson, Richard L.; Jeffrey, Frank R.; Westerberg, Roger K.

    1989-06-27

    A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

  7. Multi-chamber deposition system

    DOEpatents

    Jacobson, Richard L.; Jeffrey, Frank R.; Westerberg, Roger K.

    1989-10-17

    A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

  8. Combustor with fuel preparation chambers

    NASA Technical Reports Server (NTRS)

    Zelina, Joseph (Inventor); Myers, Geoffrey D. (Inventor); Srinivasan, Ram (Inventor); Reynolds, Robert S. (Inventor)

    2001-01-01

    An annular combustor having fuel preparation chambers mounted in the dome of the combustor. The fuel preparation chamber comprises an annular wall extending axially from an inlet to an exit that defines a mixing chamber. Mounted to the inlet are an air swirler and a fuel atomizer. The air swirler provides swirled air to the mixing chamber while the atomizer provides a fuel spray. On the downstream side of the exit, the fuel preparation chamber has an inwardly extending conical wall that compresses the swirling mixture of fuel and air exiting the mixing chamber.

  9. 44. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION CCC), ...

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

    44. AUXILIARY CHAMBER BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION CCC), LOOKING NORTHEAST SHOWING DRAIN PIPE FROM SUMP - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  10. 72. VISITOR'S CENTER, MODEL OF BOILER CHAMBER, AUXILIARY CHAMBER, REACTOR ...

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

    72. VISITOR'S CENTER, MODEL OF BOILER CHAMBER, AUXILIARY CHAMBER, REACTOR AND CANAL (LOCATION T) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

  11. Three chamber negative ion source

    DOEpatents

    Leung, Ka-Ngo; Ehlers, Kenneth W.; Hiskes, John R.

    1985-01-01

    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.

  12. Crystals in magma chambers

    NASA Astrophysics Data System (ADS)

    Higgins, M.

    2011-12-01

    Differentiation processes in igneous systems are one way in which the diversity of igneous rocks is produced. Traditionally, magmatic diversity is considered as variations in the overall chemical composition, such as basalt and rhyolite, but I want to extend this definition to include textural diversity. Such textural variations can be manifested as differences in the amount of crystalline (and immiscible liquid) phases and in the origin and identity of such phases. One important differentiation process is crystal-liquid separation by floatation or decantation, which clearly necessitates crystals in the magma. Hence, it is important to determine if magmas in chambers (sensu lato) have crystals. The following discussion is framed in generalities - many exceptions occur. Diabase (dolerite) dykes are a common, widespread result of regional mafic magmatism. The rims of most diabase dykes have few or no phenocrysts and crystals in the cores are commonly thought to have crystallized in place. Hence, this major mafic magmatic source did not have crystals, although compositional diversity of these dykes is commonly explained by crystal-liquid separation. This can be resolved if crystallisation was on the walls on the magma chamber. Similarly, most flood basalts are low in crystals and separation of those that are present cannot always explain the observed compositional diversity. Crystal-rich flows do occur, for example the 'Giant Plagioclase Basalts' of the Deccan series, but the crystals are thought to form or accumulate in a crystal-rich zone beneath the roof of the chamber - the rest of the chamber probably has few crystals. Some magmas from Hawaii contain significant amounts of olivine crystals, but most of these are deformed and cannot have crystallised in the chamber. In this case the crystals are thought to grow as the magma passes through a decollement zone. They may have grown on the walls or been trapped by filters. Basaltic andesite ignimbrites generally have

  13. Electrostatic Levitator Vacuum Chambers

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (such as the deuterium arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  14. Digital optical spark chambers

    NASA Technical Reports Server (NTRS)

    Evenson, Paul; Tuska, Evelyn

    1989-01-01

    The authors constructed and tested a prototype digital readout system for optical spark chambers using a linear, solid-state charge-coupled-device detector array. Position resolution of 0.013 mm (sigma) over a 25-cm field of view has been demonstrated. It is concluded that this technique should permit the construction of economical, lightweight and low-power trajectory hodoscopes for use in cosmic-ray instrumentation on balloons and in spacecraft.

  15. Columbium Chamber Fabrication Study

    DTIC Science & Technology

    1984-07-01

    materials. Demonstrate CVO close-out of slotted, filled, C103 columbium alloy panels and subsequent removal of the filler materials. 1.0, Introduction...their removal subsequent to CV0 of a columbium close-out. C103 columbium alloy plate, procured to Aeronautical Materials Specification (SAE) -- AMS 7852...into the chamber. Surface oxygen contamination of the C103 columbium alloy wcs evident in all metallographic sections. 8.1 LOW TEMPERATURE DEPOSIT

  16. Combustion chamber noise suppressor

    SciTech Connect

    Livingston, A.M.

    1986-08-19

    A combustion chamber is described for a hot fog generating machine comprising a hollow cylindrical combustion chamber shell having a closure plate at one end and outlet means at the opposite end for directing hot combustion gasses to a fogging nozzle, air inlet means disposed adjacent the outlet means, fuel inlet means and ignition means mounted in the closure plate and liner means disposed concentrically within the cylindrical combustion chamber for controlling the flow of air and combustion gasses within the shell. The liner means includes a liner base having a frustroconical configuration with the smaller diameter end thereof disposed in communication with the outlet means and with the larger diameter end thereof disposed in spaced relation to the shell, circumferentially spaced, longitudinally extending fins extending outwardly from the liner base intermediate the liner base and the shell, a cylindrical liner midsection having circumferentially spaced fins extending outwardly therefrom between the midsection and the shell with the fins supporting the midsection on the larger diameter end of the liner base.

  17. Is Climate Simulation in Growth Chambers Necessary?

    Treesearch

    Z.M. Wang; K.H. Johnsen; M.J. Lechowicz

    1999-01-01

    In the expression of their genetic potential as phenotypes, trees respond to environmental cues such as photoperiod, temperature and soil and atmospheric water. However, growth chamber experiments often utilize simple and standard environmental conditions that might not provide these important environmental signals. We conducted a study to compare seedling growth in...

  18. Projected ecosystem impact of the Prairie Heating and CO2 Enrichment experiment.

    PubMed

    Parton, William J; Morgan, Jack A; Wang, Guiming; Del Grosso, Stephen

    2007-01-01

    The Prairie Heating and CO2 Enrichment (PHACE) experiment has been initiated at a site in southern Wyoming (USA) to simulate the impact of warming and elevated atmospheric CO2 on ecosystem dynamics for semiarid grassland ecosystems. The DAYCENT ecosystem model was parametrized to simulate the impact of elevated CO2 at the open-top chamber (OTC) experiment in north-eastern Colorado (1996-2001), and was also used to simulate the projected ecosystem impact of the PHACE experiments during the next 10 yr. Model results suggest that soil water content, plant production, soil respiration, and nutrient mineralization will increase for the high-CO2 treatment. Soil water content will decrease for all years, while nitrogen mineralization, soil respiration, and plant production will both decrease and increase under warming depending on yearly differences in water stress. Net primary production (NPP) will be greatest under combined warming and elevated CO2 during wet years. Model results are consistent with empirical field data suggesting that water and nitrogen will be critical drivers of the semiarid grassland response to global change.

  19. Vertical two chamber reaction furnace

    DOEpatents

    Blaugher, Richard D.

    1999-03-16

    A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

  20. Vertical two chamber reaction furnace

    DOEpatents

    Blaugher, R.D.

    1999-03-16

    A vertical two chamber reaction furnace is disclosed. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

  1. Seedling-Size Fumigation Chambers

    Treesearch

    Keith F. Jensen; Frederick W. Bender

    1977-01-01

    The design of fumigation chambers is described. Each chamber has individual temperature, humidity, light, and pollutant control. Temperature is variable from 15 to 35ºC and controlled within ± 1ºC. Humidity is variable from 25 to 95 percent and controlled within ± 3 percent. Seedlings have been successfully grown in these chambers...

  2. Warmer temperatures stimulate respiration and reduce net ecosystem productivity in a northern Great Plains grassland: Analysis of CO2 exchange in automatic chambers

    NASA Astrophysics Data System (ADS)

    Flanagan, L. B.

    2013-12-01

    The interacting effects of altered temperature and precipitation are expected to have significant consequences for ecosystem net carbon storage. Here I report the results of an experiment that evaluated the effects of elevated temperature and altered precipitation on ecosystem CO2 exchange in a northern Great Plains grassland, near Lethbridge, Alberta Canada. Open-top chambers were used to establish an experiment in 2012 with three treatments (control, warmed, warmed plus 50% of normal precipitation input). A smaller experiment with only the two temperature treatments (control and warmed) was conducted in 2013. Continuous half-hourly net CO2 exchange measurements were made using nine automatic chambers during May-October in both years. My objectives were to determine the sensitivity of the ecosystem carbon budget to temperature and moisture manipulations, and to test for direct and indirect effects of the environmental changes on ecosystem CO2 exchange. The experimental manipulations resulted primarily in a significant increase in air temperature in the warmed treatment plots. A cumulative net loss of carbon or negative net ecosystem productivity (NEP) occurred during May through September in the warmed treatment (NEP = -659 g C m-2), while in the control treatment there was a cumulative net gain of carbon (NEP = +50 g C m-2). An eddy covariance system that operated at the site, over a footprint region that was not influenced by the experimental treatments, also showed a net gain of carbon by the ecosystem. The reduced NEP was due to higher plant and soil respiration rates in the warmed treatment that appeared to be caused by a combination of: (i) higher carbon substrate availability indirectly stimulating soil respiration in the warmed relative to the control treatment, and (ii) a strong increase in leaf respiration likely caused by a shift in electron partitioning to the alternative pathway respiration in the warmed treatment, particularly when exposed to high

  3. Characteristic and performance of a simple thoron chamber.

    PubMed

    Zhao, C; Zhuo, W; Chen, B; Zhang, H

    2010-10-01

    For calibration and intercomparison experiments, a thoron chamber with an inner volume of 300 l was designed based on a programmable constant temperature and humidity testing device in this work. The commercial lantern mantles enriched with (232)Th were used as the (220)Rn source and the mantles were set in 3×3×3 points of lattice style inside the chamber. Experimental studies showed that (220)Rn concentrations in the chamber could be easily controlled and adjusted from about 0.5 to 80 kBq m(-3) through manual settings of the relative humidity and temperature, and the spatial distribution of (220)Rn in the chamber was fairly homogeneous.

  4. PICO Bubble Chambers for Dark Matter Searches: Future Prospects

    NASA Astrophysics Data System (ADS)

    Neilson, Russell; PICO Collaboration

    2017-01-01

    The PICO collaboration uses bubble chambers to search for WIMP dark matter particles. The bubble chambers are operated in a moderately superheated state, providing superb rejection of the dominant gamma background, and are filled with fluorinated target fluids ideally suited for investigating spin-dependent WIMP-proton interactions. PICO currently operates a 2-liter (PICO-2L) and a 32-liter (PICO-60) bubble chamber at the SNOLAB deep underground laboratory. I will discuss recent activities by the PICO collaboration to understand and mitigate an anomalous background that has impacted previous dark matter searches, plans for the operating experiments, and prospects for a future ton-scale PICO bubble chamber.

  5. Mobility of heavy metals from polluted sediments of a semi-enclosed basin: in situ benthic chamber experiments in Taranto's Mar Piccolo (Ionian Sea, Southern Italy).

    PubMed

    Emili, Andrea; Acquavita, Alessandro; Covelli, Stefano; Spada, Lucia; Di Leo, Antonella; Giandomenico, Santina; Cardellicchio, Nicola

    2016-07-01

    In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto (Italy), one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn). Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals (Zn > Ni > Cr > As > Cu > Pb). A Hg-specific extraction procedure showed that most of the element (93.1 %) occurs in a fraction comprising Hg bound to Fe/Mn oxi-hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) were directly measured at the sediment-water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg (97 μg m(-2) day(-1)) was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy-hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in

  6. Commissioning of SLAC SLD 45-Degree Chambers

    SciTech Connect

    Eschenburg, Vance O.

    2002-07-19

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

  7. Central Drift Chamber for Belle-II

    NASA Astrophysics Data System (ADS)

    Taniguchi, N.

    2017-06-01

    The Central Drift Chamber (CDC) is the main device for tracking and identification of charged particles for Belle-II experiment. The Belle-II CDC is cylindrical wire chamber with 14336 sense wires, 2.3 m-length and 2.2 m-diameter. The wire chamber and readout electronics have been completely replaced from the Belle CDC. The new readout electronics system must handle higher trigger rate of 30 kHz with less dead time at the design luminosity of 8 × 1035 cm-2s-1. The front-end electronics are located close to detector and send digitized signal through optical fibers. The Amp-Shaper-Discriminator chips, FADC and FPGA are assembled on a single board. Belle-II CDC with readout electronics has been installed successfully in Belle structure in October 2016. We will present overview of the Belle-II CDC and status of commissioning with cosmic ray.

  8. Multi-anode ionization chamber

    DOEpatents

    Bolotnikov, Aleksey E.; Smith, Graham; Mahler, George J.; Vanier, Peter E.

    2010-12-28

    The present invention includes a high-energy detector having a cathode chamber, a support member, and anode segments. The cathode chamber extends along a longitudinal axis. The support member is fixed within the cathode chamber and extends from the first end of the cathode chamber to the second end of the cathode chamber. The anode segments are supported by the support member and are spaced along the longitudinal surface of the support member. The anode segments are configured to generate at least a first electrical signal in response to electrons impinging thereon.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Chamber transport for heavy ion fusion

    NASA Astrophysics Data System (ADS)

    Olson, Craig L.

    2014-01-01

    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.

  12. Wire chambers revisited.

    PubMed

    Ott, R J

    1993-04-01

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

  13. Ionization chamber dosimeter

    DOEpatents

    Renner, Tim R.; Nyman, Mark A.; Stradtner, Ronald

    1991-01-01

    A method for fabricating an ion chamber dosimeter collecting array of the type utilizing plural discrete elements formed on a uniform collecting surface which includes forming a thin insulating layer over an aperture in a frame having surfaces, forming a predetermined pattern of through holes in the layer, plating both surfaces of the layer and simultaneously tilting and rotating the frame for uniform plate-through of the holes between surfaces. Aligned masking and patterned etching of the surfaces provides interconnects between the through holes and copper leads provided to external circuitry.

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

    SciTech Connect

    Spiegel, L.; Cataldi, G.; Elia, V.; Mazur, P.; Murphy, C.T.; Smith, R.P.; Yang, W.; Alexopoulos, T.; Durandet, C.; Erwin, A.; Jennings, J.; Antoniazzi, L.; Introzzi, G.; Lanza, A.; Liguori, G.; Torre, P. |; Arenton, M.; Conetti, S.; Cox, B.; Dukes, E.; Golovatyuk, V.; Hanlet, P.; McManus, A.; Nelson, K.; Recagni, M.; Segal, J.; Sun, J.; Ballagh, C.; Bingham, H.; Kaeding, T.; Lys, J.; Misawa, S.; Blankman, A.; Borodin, S.; Kononenko, W.; Newcomer, M.; Selove, W.; Trojak, T.; VanBerg, R.; Zhang, S.N.; Block, M.; Corti, G.; LeCompte, T.; Rosen, J.; Yao, T.; Boden, A.; Cline, D.; Ramachandran, S.; Rhoades, J.; Tokar, S.; Budagov, J.; Tsyganov, E.; Cao, Z.L.; He, M.; Wang, C.; Wei, C.; Zhang, N.; Chen, T.Y.; Yao, N.; Clark, K.; Jenkins, M.; Cooper, M.; Creti, P.; Gorini, E.; Grancagnolo, F.; Panareo, M. |; Fortney, L.; Kowald, W.; Haire, M.; Judd, D.; Turnbull, L.; Wagoner, D.; Lau, K.; Mo, G.; Trischuk, J.

    1991-11-01

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

  15. Convection and mixing in magma chambers

    NASA Astrophysics Data System (ADS)

    Turner, J. S.; Campbell, I. H.

    1986-08-01

    released continuously during crystallization and rises to the top of the chamber with little mixing. Overturning of a gas-rich mafic lower layer into a cooler silicic layer can cause a sudden quenching, with the rapid release of gas which could trigger an explosive eruption. Mixing can also occur during eruption, as two layers are drawn up simultaneously from a stratified chamber when a critical flow velocity is exceeded, and they then mix in the outlet vent. Laboratory experiments suggest, however, that magma mixing is inhibited by large viscosity differences, both during the filling and emptying of a magma chamber. Scaling these results to magmas indicates that a basaltic magma can flow into the bottom of a chamber containing rhyolite with little or no mixing between them, and that these two magma types can also flow out through the same exit vent with limited mixing. Each of the phenomena discussed in this review has been studied, at least in a qualitative way, using laboratory experiments to identify and understand a significant physical process occurring in magma chambers. The field of geological fluid mechanics and its application to these problems is still very new, and further advances seem assured as new phenomena are identified and more detailed and quantitative analogue experiments are developed to study them.

  16. Diogene pictorial drift chamber

    SciTech Connect

    Gosset, J.

    1984-01-01

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

  17. Mush Column Magma Chambers

    NASA Astrophysics Data System (ADS)

    Marsh, B. D.

    2002-12-01

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

  18. The search for primary particle tracks in nucleon-nucleus interactions with gamma ray energy ΣEγ ≥ 3 TeV registered in stratospheric X-ray emulsion chambers using data of the RUNJOB experiment

    NASA Astrophysics Data System (ADS)

    Zayarnaya, I. S.; Irkhina, T. A.

    2017-06-01

    We present here the result of a retreatment of data from the RUNJOB (RUssia-Nippon JOint Balloon) experiment of nucleon-nucleus interactions registered in stratospheric X-ray emulsion chambers (REC) using a new method for searching and tracing of galactic particles in nuclear emulsions. In about halfcof these interactions (˜ 50) recorded in REC RUNJOB`96-3B, RUNJOB`97-6A and RUNJOB`99-11A,B with energy released in the electromagnetic component ΣEγ ≥ 3 TeV and ΣEγ ≥ 5 TeV respectively, single charged particle tracks are not found within the search area defined individually by the particle track location accuracy. The absence of primary proton tracks is consistent with the original treatment of the RUNJOB experimental data. There is a difference in the zenith angular distribution for two groups of events in which a single charged particle track is observed or absent. The average penetration depth of the primary particles in REC to the interaction vertex in the zenith angle range from 60∘ to 79∘ differs by a factor two for these groups.

  19. HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF ...

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

    HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF PLENUM WITH ATTACHED DRAFT REGULATOR. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  20. Costs and Benefits of Underground Pupal Chambers Constructed by Insects: A Test Using Manduca sexta.

    PubMed

    Sprague, Jonathan C; Woods, H Arthur

    2015-01-01

    Many holometabolous insects metamorphose in belowground pupal chambers. Although the chambers may be elaborate and their construction costly, their functions are unknown. Using laboratory and field experiments, we examined the costs and functions of chambers made by the hawk moth Manduca sexta (Sphingidae). Costs were large in some circumstances; prepupal larvae lost up to 60% of their body mass when constructing chambers in dry soils. We tested three alternative hypotheses about what, if anything, chambers do for the individuals that make them: (1) chambers provide critical open space underground, allowing room for ecdysis and preventing soil from deforming the metamorphosing individual; (2) chambers raise the local relative humidity, so that cuticular and respiratory water losses are minimized; and (3) chamber walls prevent predators and pathogens from attacking. The data support the first hypothesis (about open space) and largely exclude the other two. These results provide a simple and potentially broad explanation for the evolution of chamber building in metamorphosing insects.

  1. Detecting dark matter with scintillating bubble chambers

    NASA Astrophysics Data System (ADS)

    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.

  2. Characteristics of a large system of pad readout wire proportional chambers for the HPC calorimeter

    SciTech Connect

    Camporesi, T.; Cavallo, F.R.; Giordano, V.; Laurenti, G.; Molinari, G.; Navarria, F.L.; Privitera, P.; Rovelli, T.; Valenti, G.; Zucchini, A.

    1989-02-01

    A large system of wire proportional chambers is being constructed for the readout of the High-Density Projection Chamber (HPC) of the DELPHI experiment at the Large Electron-Positron storage ring. The system consists of 144 chambers, each 0.3 m/sup 2/ wide and read out via cathode pads, located at the end of the HPC drift volume.

  3. Crosstalk Studies of a Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Ryer, Jonathan

    2008-10-01

    The crosstalk between various pads of a Time Projection Chamber (TPC) developed for the experiment MuSun was studied. Crosstalk between TPC pads must be studied and understood in order for proper muon path reconstruction to be obtained. A printed circuit board was developed to use capacitive coupling to transmit a signal pulse onto the TPC, where the crosstalk of the transmitted signal was studied.

  4. On Orbit Daytime Solar Heating Effects: A Comparison of Ground Chamber Arcing Results

    NASA Technical Reports Server (NTRS)

    Galofaro, J.; Vayner, B.; Ferguson, D.

    2004-01-01

    The purpose of the current experiment is to make direct comparisons between the arcing results obtained from the diffusion pumped vertical chamber and our newly renovated Teney vacuum chamber which is equipped with a cryogenic pump. Recall that the prior reported results obtained for the Vertical chamber were nominal at best, showing only a slight reduction in the arc rate after 5 heating cycles at the lower bias potentials and virtually no changes at high potential biases. It was concluded that the vertical chamber was unable to remove enough water vapor from the chamber to adequately test the arcing criterion. Because the cryo-pumped Teney chamber has a ten times better pumping speed, (40,000 liters per sec compared to 4,000 liters per sec for the diffusion pumped vertical chamber), a decision was made to retest that experiment in both the Teney and Vertical vacuum chambers. A comparison of the various data is presented with encouraging results.

  5. On-Orbit Daytime Solar Heating Effects: A Comparison of Ground Chamber Arcing Results

    NASA Technical Reports Server (NTRS)

    Galofaro, J.; Vayner, B.; Ferguson, D.

    2004-01-01

    The purpose of the current experiment is to make direct comparisons between the arcing results obtained from the diffusion pumped vertical chamber and our newly renovated Teney vacuum chamber which is equipped with a cryogenic pump. Recall that the prior reported results obtained for the Vertical chamber were nominal at best, showing only a slight reduction in the arc rate after five heating cycles at the lower bias potentials and virtually no changes at high potential biases. It was concluded that the vertical chamber was unable to remove enough water vapor from the chamber to adequately test the arcing criterion. Because the cryo-pumped Teney chamber has a ten times better pumping speed, (40,000 liters per sec compared to 4,000 liters per sec for the diffusion pumped vertical chamber), a decision was made to retest that experiment in both the Teney and Vertical vacuum chambers. A comparison of the various data is presented with encouraging results.

  6. Small rocket flowfield diagnostic chambers

    NASA Technical Reports Server (NTRS)

    Morren, Sybil; Reed, Brian

    1993-01-01

    Instrumented and optically-accessible rocket chambers are being developed to be used for diagnostics of small rocket (less than 440 N thrust level) flowfields. These chambers are being tested to gather local fluid dynamic and thermodynamic flowfield data over a range of test conditions. This flowfield database is being used to better understand mixing and heat transfer phenomena in small rockets, influence the numerical modeling of small rocket flowfields, and characterize small rocket components. The diagnostic chamber designs include: a chamber design for gathering wall temperature profiles to be used as boundary conditions in a finite element heat flux model; a chamber design for gathering inner wall temperature and static pressure profiles; and optically-accessible chamber designs, to be used with a suite of laser-based diagnostics for gathering local species concentration, temperature, density, and velocity profiles. These chambers were run with gaseous hydrogen/gaseous oxygen (GH2/GO2) propellants, while subsequent versions will be run on liquid oxygen/hydrocarbon (LOX/HC) propellants. The purpose, design, and initial test results of these small rocket flowfield diagnostic chambers are summarized.

  7. LRL 25-inch Bubble Chamber

    DOE R&D Accomplishments Database

    Alvarez, L. W.; Gow, J. D.; Barrera, F.; Eckman, G.; Shand, J.; Watt, R.; Norgren, D.; Hernandez, H. P.

    1964-07-08

    The recently completed 25-inch hydrogen bubble chamber combines excellent picture quality with a fast operating cycle. The chamber has a unique optical system and is designed to take several pictures each Bevatron pulse, in conjunction with the Bevatron rapid beam ejection system.

  8. Fast-response cloud chamber

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.

    1977-01-01

    Wall structure keeps chambers at constant, uniform temperature, yet allows them to be cooled rapidly if necessary. Wall structure, used in fast-response cloud chamber, has surface heater and coolant shell separated by foam insulation. It is lightweight and requires relatively little power.

  9. Cooling of High Pressure Rocket Thrust Chambers with Liquid Oxygen

    NASA Technical Reports Server (NTRS)

    Price, H. G.

    1980-01-01

    An experimental program using hydrogen and oxygen as the propellants and supercritical liquid oxygen (LOX) as the coolant was conducted at 4.14 and 8.274 MN/square meters (600 and 1200 psia) chamber pressure. Data on the following are presented: the effect of LOX leaking into the combustion region through small cracks in the chamber wall; and verification of the supercritical oxygen heat transfer correlation developed from heated tube experiments; A total of four thrust chambers with throat diameters of 0.066 m were tested. Of these, three were cyclically tested to 4.14 MN/square meters (600 psia) chamber pressure until a crack developed. One had 23 additional hot cycles accumulated with no apparent metal burning or distress. The fourth chamber was operated at 8.274 MN/square meters (1200 psia) pressure to obtain steady state heat transfer data. Wall temperature measurements confirmed the heat transfer correlation.

  10. Plant growth chamber based on space proven controlled environment technology

    SciTech Connect

    Ignatius, R.W.; Ignatius, M.H.; Imberti, H.J.

    1997-01-01

    Quantum Devices, Inc., in conjunction with Percival Scientific, Inc., and the Wisconsin Center for Space Automation and Robotics (WCSAR) have developed a controlled environment plant growth chamber for terrestrial agricultural and scientific applications. This chamber incorporates controlled environment technology used in the WCSAR ASTROCULTURE{trademark} flight unit for conducting plant research on the Space Shuttle. The new chamber, termed CERES 2010, features air humidity, temperature, and carbon dioxide control, an atmospheric contaminant removal unit, an LED lighting system, and a water and nutrient delivery system. The advanced environment control technology used in this chamber will increase the reliability and repeatability of environmental physiology data derived from plant experiments conducted in this chamber. {copyright} {ital 1997 American Institute of Physics.}

  11. Calibration of PICO Bubble Chamber Dark Matter Detectors

    NASA Astrophysics Data System (ADS)

    Jin, Miaotianzi; PICO Collaboration

    2016-03-01

    The PICO Collaboration builds bubble chambers for the direct detection of WIMP dark matter. I will present the suite of calibration experiments performed to measure the sensitivity of these chambers to nuclear recoils (the expected WIMP signal) and to gamma rays (a common background to the WIMP signal). These calibrations include measurements with a 10-ml C3F8 bubble chamber at Northwestern University and with a 30-ml C3F8 bubble chamber deployed in the University of Montreal's tandem Van de Graaf facility, giving the bubble chamber response to a variety of gamma rays, broad-spectrum neutron sources, and mono-energetic low energy neutrons. I will compare our measured sensitivities to those predicted by a simple thermodynamic model and will show how the results impact our ability to detect dark matter, with a focus on light WIMP searches. Supported by DOE Grant: DE-SC0012161.

  12. National Ignition Facility Target Chamber

    SciTech Connect

    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 was

  13. Ion chamber based neutron detectors

    DOEpatents

    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.

  14. Design and performance of a dynaniic gas flux chamber.

    PubMed

    Reichman, Rivka; Rolston, Dennis E

    2002-01-01

    Chambers are commonly used to measure the emission of many trace gases and chemicals from soil. An aerodynamic (flow through) chamber was designed and fabricated to accurately measure the surface flux of trace gases. Flow through the chamber was controlled with a small vacuum at the outlet. Due to the design using fans, a partition plate, and aerodynamic ends, air is forced to sweep parallel and uniform over the entire soil surface. A fraction of the air flowing inside the chamber is sampled in the outlet. The air velocity inside the chamber is controlled by fan speed and outlet suction flow rate. The chamber design resulted in a uniform distribution of air velocity at the soil surface. Steady state flux was attained within 5 min when the outlet air suction rate was 20 L/min or higher. For expected flux rates, the presence of the chamber did not affect the measured fluxes at outlet suction rates of around 20 L/min, except that the chamber caused some cooling of the surface in field experiments. Sensitive measurements of the pressure deficit across the soil layer in conjunction with measured fluxes in the source box and chamber outlet show that the outflow rate must be controlled carefully to minimize errors in the flux measurements. Both over- and underestimation of the fluxes are possible if the outlet flow rate is not controlled carefully. For this design, the chamber accurately measured steady flux at outlet air suction rates of approximately 20 L/min when the pressure deficit within the chamber with respect to the ambient atmosphere ranged between 0.46 and 0.79 Pa.

  15. High-energy Physics with Hydrogen Bubble Chambers

    DOE R&D Accomplishments Database

    Alvarez, L. W.

    1958-03-07

    Recent experience with liquid hydrogen bubble chambers of 25 and 40 cm dia. in high-energy physics experiments is discussed. Experiments described are: interactions of K{sup -} mesons with protons, interactions of antiprotons with protons, catalysis of nuclear fusion reactions by muons, and production and decay of hyperons from negative pions. (W.D.M.)

  16. Telerobotic Tending of Space Based Plant Growth Chamber

    NASA Technical Reports Server (NTRS)

    Backes, P. G.; Long, M. K.; Das, H.

    1994-01-01

    The kinematic design of a telerobotic mechanism for tending a plant growth space science experiment chamber is described. Ground based control of tending mechanisms internal to space science experiments will allow ground based principal investigators to interact directly with their space science experiments.

  17. The high momentum spectrometer drift chambers

    NASA Astrophysics Data System (ADS)

    Abbott, D.; Baker, O. K.; Beaufait, J.; Bennett, C.; Bryant, E.; Carlini, R.; Kross, B.; McCauley, A.; Naing, W.; Shin, T.; Vulcan, W.

    1992-12-01

    The High Momentum Spectrometer in Hall C will use planar drift chambers for charged particle track reconstruction. The chambers are constructed using well understood technology and a conventional gas mixture. Two (plus one spare) drift chambers will be constructed for this spectrometers. Each chamber will contain 6 planes of readout channels. This paper describes the chamber design and gas handling system used.

  18. The SAMURAI Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Dye, Steven

    2011-10-01

    The SAMURAI Time Projection Chamber (TPC) will be used to study particle collisions by colliding a beam of particles with a stationary gas which will be contained in a field cage inside the TPC. When the beam collides with the gas, charged particles are accelerated into the pad plane by an electric field. The paths of these particles will be curved by a magnetic field created by the SAMURAI magnet at the RIKEN facility in Japan. The charged particles will then collide with the pad plane which will be located on the bottom of the TPC. The pad plane will take these collisions and create electrical signals and send them to supporting electronics where the data can be interpreted. The TPC will be used to help determine the Equation of State for asymmetric nuclear matter. Measurements of neutron, proton, 3H and 3He flow will be taken with the NEBULA array which consists of nebula scintillators. The poster will contain information on the laser calibration system and the electronics that will be used for the TPC. The electronics used are the same electronics used in the STAR TPC experiment.

  19. Experimental Whole-Ecosystem Warming Alters Vegetation Phenology in a Boreal Spruce Bog: Initial Results from the SPRUCE Experiment

    NASA Astrophysics Data System (ADS)

    Richardson, A. D.

    2016-12-01

    Phenology is one of the most robust indicators of the biological impacts of global change. However, the response of phenology to future environmental conditions still remains highly uncertain because of the challenges associated with conducting realistic manipulative experiments. At the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) experiment in the north-central United States, experimental temperature (0 to +9°C above ambient) and CO2 (ambient and elevated) treatments are being applied to mature, and intact, Picea mariana-Sphagnum spp. bog communities in their native habitat through the use of ten large (approximately 12 m wide, 10 m high) open-topped enclosures. We are tracking vegetation green-up and senescence in these chambers using repeat digital photography. Within each chamber, images are recorded every 30 minutes and uploaded to PhenoCam (http://phenocam.sr.unh.edu), where processed to yield quantitative measures of canopy color. These data are complemented by on-the-ground phenological data collected by human observers. Air warming treatments at SPRUCE began in August 2015. We observed a delay in senescence during autumn 2015 (2-5 days per degree of warming) and an advance in onset during spring 2016 (1-4 days per degree of warming). These patterns are robust across species and methods of phenological observation (i.e. camera-based vs. human observer). And, our results show very little evidence for photoperiod acting as a constraint on the response to warming. Early spring onset and consequent loss of frost hardiness in the warmest chambers proved disadvantageous when a brief period of extreme cold (to -12°C in the control chambers, to -3°C in the +9°C chambers) followed a month of generally mild weather. Foliage mortality for both Larix and Picea was immediate and severe, although both species subsequently re-flushed. These results give support for the hypothesis that warming may enhance the likelihood of spring frost

  20. Gas and aerosol wall losses in Teflon film smog chambers

    SciTech Connect

    McMurry, P.H.; Grosjean, D.

    1985-12-01

    Large smog chambers (approx.60 m/sup 3/) constructed of FEP Teflon film are frequently used to study photochemistry and aerosol formation in model chemical systems. In a previous paper a theory for aerosol wall loss rates in Teflon film smog chambers was developed; predicted particle loss rates were in good agreement with measured rates. In the present paper, measurements of wall deposition rates and the effects of wall losses on measurements of gas-to-particle conversion in smog chambers are discussed. Calculations indicate that a large fraction of the aerosol formed in several smog chamber experiments was on the chamber walls at the end of the experiment. Estimated values for particulate organic carbon yield for several precursor hydrocarbons increased by factors of 1.3-6.0 when wall deposition was taken into account. The theory is also extended to loss rates of gaseous species. Such loss rates are either limited by diffusion through a concentration boundary layer near the surface or by uptake at the surface. It is shown that for a typical 60-m/sup 3/ Teflon film smog chamber, gas loss rates are limited by surface reaction rates if mass accommodation coefficients are less than 6 x 10/sup -6/. It follows that previously reported loss rates of several gases in a chamber of this type were limited by surface reactions.

  1. A high rate proportional chamber

    SciTech Connect

    Henderson, R.; Fraszer, W.; Openshaw, R.; Sheffer, G.; Salomon, M.; Dew, S.; Marans, J.; Wilson, P.

    1987-02-01

    Gas mixtures with high specific ionization allow the use of small interelectrode distances while still maintaining full efficiency. With the short electron drift distances the timing resolution is also improved. The authors have built and operated two 25 cm/sup 2/ chambers with small interelectrode distances. Also single wire detector cells have been built to test gas mixture lifetimes. Various admixtures of CF/sub 4/, DME, Isobutane, Ethane and Argon have been tested. Possible applications of such chambers are as beam profile monitors, position tagging of rare events and front end chambers in spectrometers.

  2. Energy deposition in discharge chamber of lightning protection multichamber system

    NASA Astrophysics Data System (ADS)

    Pinchuk, M. E.; Budin, A. V.; Kumkova, I. I.; Bogomaz, A. A.; Sivaev, A. D.; Chusov, A. N.; Zaynalov, R. I.

    2016-11-01

    The experimental data of energy deposition distribution along discharge chamber of lightning protection multichamber system in initial stage of discharge process aimed to model lightning current impulse up to 10 kA is presented. A multichamber system is a series connection of discharge chambers. According to our experiments the shock wave formation occurs during the breakdown phase between electrodes located at the bottom of discharge chamber. The consequent energy deposition during discharge development goes in the whole volume bounded by shock wave front.

  3. Structurally compliant rocket engine combustion chamber: Experimental and analytical validation

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert S.; Arya, Vinod K.; Kazaroff, John M.; Halford, Gary R.

    1994-01-01

    A new, structurally compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations.

  4. Dark matter searches with PICO bubble chambers: An overview

    NASA Astrophysics Data System (ADS)

    Harris, Orin; PICO Collaboration

    2017-01-01

    The PICO collaboration uses bubble chambers to search for dark matter, with world-leading sensitivity to the direct-detection of WIMPs with spin-dependent couplings to protons. PICO currently operates a 2 liter (PICO-2L) and a 32 liter (PICO 60) bubble chamber at the SNOLAB deep underground laboratory, and is currently constructing a 40 liter demonstration device that is expected to eliminate an anomalous background that has previously proven significant for the scaling of the bubble chamber technique to a future ton-scale experiment (PICO-500). A discussion of the technology, recent progress, and future plans will be presented.

  5. Radiated Susceptibility Tests in Thermal Vacuum Chambers for Space Systems

    NASA Astrophysics Data System (ADS)

    Anon Cancela, Manuel; Hernandez-Gomez, Daniel; Vazquez-Pascual, Mercedes; Lopez-Sanz, Daniel

    2016-05-01

    INTA EMC Area has a wide experience in performing Radiated Susceptibility (RS) tests according to civilian, military and aeronautical standards in Mode Tuned Chambers (MTC) for national and international projects; besides, INTA has two Thermal Vacuum Chamber (TVC) facilities in service for Space Systems tests. In order to perform RS tests to Space Systems in a more realistic environment, INTA EMC Area has stablished an internal research program to develop a procedure to perform this kind of tests inside a TVC as a Mode Tuned Chamber (MTC). In this paper the results of the TVC-04 validation measurements as a MTC are presented.

  6. Environmental chamber studies of atmospheric reactivities of volatile organic compounds: Effects of varying chamber and light source

    SciTech Connect

    Carter, W.; Luo, D.; Malkina, I.; Pierce, J.

    1995-05-01

    Photochemical oxidant models are essential tools for assessing effects of emissions changes on ground-level ozone formation. Such models are needed for predicting the ozone impacts of increased alternative fuel use. The gas-phase photochemical mechanism is an important component of these models because ozone is not emitted directly, but is formed from the gas-phase photochemical reactions of the emitted volatile organic compounds (VOCs) and oxides of nitrogen (NO{sub x}) in air. The chemistry of ground level ozone formation is complex; hundreds of types of VOCs being emitted into the atmosphere, and most of their atmospheric reactions are not completely understood. Because of this, no chemical model can be relied upon to give even approximately accurate predictions unless it has been evaluated by comparing its predictions with experimental data. Therefore an experimental and modeling study was conducted to assess how chemical mechanism evaluations using environmental chamber data are affected by the light source and other chamber characteristics. Xenon arc lights appear to give the best artificial representation of sunlight currently available, and experiments were conducted in a new Teflon chamber constructed using such a light source. Experiments were also conducted in an outdoor Teflon Chamber using new procedures to improve the light characterization, and in Teflon chambers using blacklights. These results, and results of previous runs other chambers, were compared with model predictions using an updated detailed chemical mechanism. The magnitude of the chamber radical source assumed when modeling the previous runs were found to be too high; this has implications in previous mechanism evaluations. Temperature dependencies of chamber effects can explain temperature dependencies in chamber experiments when Ta-300{degree}K, but not at temperatures below that.

  7. Large-format, high-speed, X-ray pnCCDs combined with electron and ion imaging spectrometers in a multipurpose chamber for experiments at 4th generation light sources

    NASA Astrophysics Data System (ADS)

    Strüder, Lothar; Epp, Sascha; Rolles, Daniel; Hartmann, Robert; Holl, Peter; Lutz, Gerhard; Soltau, Heike; Eckart, Rouven; Reich, Christian; Heinzinger, Klaus; Thamm, Christian; Rudenko, Artem; Krasniqi, Faton; Kühnel, Kai-Uwe; Bauer, Christian; Schröter, Claus-Dieter; Moshammer, Robert; Techert, Simone; Miessner, Danilo; Porro, Matteo; Hälker, Olaf; Meidinger, Norbert; Kimmel, Nils; Andritschke, Robert; Schopper, Florian; Weidenspointner, Georg; Ziegler, Alexander; Pietschner, Daniel; Herrmann, Sven; Pietsch, Ullrich; Walenta, Albert; Leitenberger, Wolfram; Bostedt, Christoph; Möller, Thomas; Rupp, Daniela; Adolph, Marcus; Graafsma, Heinz; Hirsemann, Helmut; Gärtner, Klaus; Richter, Rainer; Foucar, Lutz; Shoeman, Robert L.; Schlichting, Ilme; Ullrich, Joachim

    2010-03-01

    Fourth generation accelerator-based light sources, such as VUV and X-ray Free Electron Lasers (FEL), deliver ultra-brilliant (˜10 12-10 13 photons per bunch) coherent radiation in femtosecond (˜10-100 fs) pulses and, thus, require novel focal plane instrumentation in order to fully exploit their unique capabilities. As an additional challenge for detection devices, existing (FLASH, Hamburg) and future FELs (LCLS, Menlo Park; SCSS, Hyogo and the European XFEL, Hamburg) cover a broad range of photon energies from the EUV to the X-ray regime with significantly different bandwidths and pulse structures reaching up to MHz micro-bunch repetition rates. Moreover, hundreds up to trillions of fragment particles, ions, electrons or scattered photons can emerge when a single light flash impinges on matter with intensities up to 10 22 W/cm 2. In order to meet these challenges, the Max Planck Advanced Study Group (ASG) within the Center for Free Electron Laser Science (CFEL) has designed the CFEL-ASG MultiPurpose (CAMP) chamber. It is equipped with specially developed photon and charged particle detection devices dedicated to cover large solid-angles. A variety of different targets are supported, such as atomic, (aligned) molecular and cluster jets, particle injectors for bio-samples or fixed target arrangements. CAMP houses 4π solid-angle ion and electron momentum imaging spectrometers ("reaction microscope", REMI, or "velocity map imaging", VMI) in a unique combination with novel, large-area, broadband (50 eV-25 keV), high-dynamic-range, single-photon-counting and imaging X-ray detectors based on the pnCCDs. This instrumentation allows a new class of coherent diffraction experiments in which both electron and ion emission from the target may be simultaneously monitored. This permits the investigation of dynamic processes in this new regime of ultra-intense, high-energy radiation—matter interaction. After an introduction into the salient features of the CAMP chamber and

  8. Performance studies of Micro Pixel Chamber for the ATLAS upgrade

    NASA Astrophysics Data System (ADS)

    Komai, H.; Ochi, A.; Homma, Y.; Edo, Y.; Yamaguchi, T.

    2013-03-01

    The Micro Pixel Chamber (μ-PIC) is being developed as a muon chamber of the ATLAS experiment in an HL-LHC environment. In the ATLAS muon system, a high flux of fast neutron background causes instability operation of the detectors. We performed neutron irradiation tests with μ-PIC to optimize the operation gas and detector structure. In addition, we studied neutron interactions with the detector, in order to understand the effect of fast neutrons.

  9. Vaporization chambers and associated methods

    DOEpatents

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

    2017-02-21

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

  10. Cyclically controlled welding purge chamber

    NASA Technical Reports Server (NTRS)

    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.

  11. The multigap resistive plate chamber

    SciTech Connect

    Zeballos, E. Cerron; Crotty, I.; Hatzifotiadou, D.; Valverde, J. Lamas; Neupane, S.; Williams, M. C. S.; Zichichi, A.

    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.

  12. Extra Terrestrial Environmental Chamber Design

    NASA Technical Reports Server (NTRS)

    Hughes, David W.

    2008-01-01

    A vacuum chamber designed to simulate the dusty environment on the Moon or Mars has been built for Goddard Space Flight Center. The path from concept to delivery is reviewed, with lessons learned and pitfalls highlighted along the way.

  13. IRIS Leaves Thermal Vacuum Chamber

    NASA Image and Video Library

    This video shows the transportation of the IRIS observatory from the thermal vacuum chamber back to the clean tent for final testing and preparations for delivery to the launch site at Vandenberg A...

  14. Webb Instrument Inside Test Chamber

    NASA Image and Video Library

    2011-08-18

    The Mid-Infrared Instrument, a component of NASA James Webb Space Telescope, underwent testing inside the thermal space test chamber at the Science and Technology Facilities Council Rutherford Appleton Laboratory Space in Oxfordshire, England.

  15. Assessing model sensitivity and uncertainty across multiple Free-Air CO2 Enrichment experiments.

    NASA Astrophysics Data System (ADS)

    Cowdery, E.; Dietze, M.

    2015-12-01

    As atmospheric levels of carbon dioxide levels continue to increase, it is critical that terrestrial ecosystem models can accurately predict ecological responses to the changing environment. Current predictions of net primary productivity (NPP) in response to elevated atmospheric CO2 concentrations are highly variable and contain a considerable amount of uncertainty. It is necessary that we understand which factors are driving this uncertainty. The Free-Air CO2 Enrichment (FACE) experiments have equipped us with a rich data source that can be used to calibrate and validate these model predictions. To identify and evaluate the assumptions causing inter-model differences we performed model sensitivity and uncertainty analysis across ambient and elevated CO2 treatments using the Data Assimilation Linked Ecosystem Carbon (DALEC) model and the Ecosystem Demography Model (ED2), two process-based models ranging from low to high complexity respectively. These modeled process responses were compared to experimental data from the Kennedy Space Center Open Top Chamber Experiment, the Nevada Desert Free Air CO2 Enrichment Facility, the Rhinelander FACE experiment, the Wyoming Prairie Heating and CO2 Enrichment Experiment, the Duke Forest Face experiment and the Oak Ridge Experiment on CO2 Enrichment. By leveraging data access proxy and data tilling services provided by the BrownDog data curation project alongside analysis modules available in the Predictive Ecosystem Analyzer (PEcAn), we produced automated, repeatable benchmarking workflows that are generalized to incorporate different sites and ecological models. Combining the observed patterns of uncertainty between the two models with results of the recent FACE-model data synthesis project (FACE-MDS) can help identify which processes need further study and additional data constraints. These findings can be used to inform future experimental design and in turn can provide informative starting point for data assimilation.

  16. Evaluating Productivity Predictions Under Elevated CO2 Conditions: Multi-Model Benchmarking Across FACE Experiments

    NASA Astrophysics Data System (ADS)

    Cowdery, E.; Dietze, M.

    2016-12-01

    As atmospheric levels of carbon dioxide levels continue to increase, it is critical that terrestrial ecosystem models can accurately predict ecological responses to the changing environment. Current predictions of net primary productivity (NPP) in response to elevated atmospheric CO2 concentration are highly variable and contain a considerable amount of uncertainty.The Predictive Ecosystem Analyzer (PEcAn) is an informatics toolbox that wraps around an ecosystem model and can be used to help identify which factors drive uncertainty. We tested a suite of models (LPJ-GUESS, MAESPA, GDAY, CLM5, DALEC, ED2), which represent a range from low to high structural complexity, across a range of Free-Air CO2 Enrichment (FACE) experiments: the Kennedy Space Center Open Top Chamber Experiment, the Rhinelander FACE experiment, the Duke Forest FACE experiment and the Oak Ridge Experiment on CO2 Enrichment. These tests were implemented in a novel benchmarking workflow that is automated, repeatable, and generalized to incorporate different sites and ecological models. Observational data from the FACE experiments represent a first test of this flexible, extensible approach aimed at providing repeatable tests of model process representation.To identify and evaluate the assumptions causing inter-model differences we used PEcAn to perform model sensitivity and uncertainty analysis, not only to assess the components of NPP, but also to examine system processes such nutrient uptake and and water use. Combining the observed patterns of uncertainty between multiple models with results of the recent FACE-model data synthesis project (FACE-MDS) can help identify which processes need further study and additional data constraints. These findings can be used to inform future experimental design and in turn can provide informative starting point for data assimilation.

  17. Light diffusing fiber optic chamber

    DOEpatents

    Maitland, Duncan J.

    2002-01-01

    A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

  18. Compound Walls For Vacuum Chambers

    NASA Technical Reports Server (NTRS)

    Frazer, Robert E.

    1988-01-01

    Proposed compound-wall configuration enables construction of large high-vacuum chambers without having to use thick layers of expensive material to obtain necessary strength. Walls enclose chambers more than 1 m in diameter and several kilometers long. Compound wall made of strong outer layer of structural-steel culvert pipe welded to thin layer of high-quality, low-outgassing stainless steel.

  19. Development and preliminary test of a new plateau hyperbaric chamber.

    PubMed

    Sun, Liang; Ding, Meng-jiang; Cai, Tian-cai; Fan, Hao-jun; Zhang, Jian-peng

    2015-10-01

    The objective of this study is to validate the performance, define its limits, and provide details on a new plateau hyperbaric chamber at 355-, 2880-, and 4532-m high altitude. A new multiplace plateau hyperbaric chamber was designed to satisfy the needed of patients who have acute mountain sickness. Tests were conducted inside the chamber at 355-, 2880-, and 4532-m high altitude. The safely and conveniences of the new plateau hyperbaric chamber were estimated. Minimum pressures of the main compartment can reach up to 0.029, 0.022, and 0.02 MPa at 355-, 2880-, and 4532-m high altitude. During pressurization, there was no leak of air around the chamber. The time lag of pressure equilibration between main and buffer compartment varies from 30.3±2.01 to 200.5±5.44 seconds and between buffer compartment and ambient pressure varies from 60.2±4.13 to 215.9±6.76 seconds. The chamber can be applicated for acute mountain sickness treatment safety and convenience. However, further experience about animals and human within the chamber is needed to improve the hardware and establish conditions of effective utilization of this equipment in the high altitude. Copyright © 2015. Published by Elsevier Inc.

  20. Constraining a hybrid volatility basis-set model for aging of wood-burning emissions using smog chamber experiments: a box-model study based on the VBS scheme of the CAMx model (v5.40)

    NASA Astrophysics Data System (ADS)

    Ciarelli, Giancarlo; El Haddad, Imad; Bruns, Emily; Aksoyoglu, Sebnem; Möhler, Ottmar; Baltensperger, Urs; Prévôt, André S. H.

    2017-06-01

    In this study, novel wood combustion aging experiments performed at different temperatures (263 and 288 K) in a ˜ 7 m3 smog chamber were modelled using a hybrid volatility basis set (VBS) box model, representing the emission partitioning and their oxidation against OH. We combine aerosol-chemistry box-model simulations with unprecedented measurements of non-traditional volatile organic compounds (NTVOCs) from a high-resolution proton transfer reaction mass spectrometer (PTR-MS) and with organic aerosol measurements from an aerosol mass spectrometer (AMS). Due to this, we are able to observationally constrain the amounts of different NTVOC aerosol precursors (in the model) relative to low volatility and semi-volatile primary organic material (OMsv), which is partitioned based on current published volatility distribution data. By comparing the NTVOC / OMsv ratios at different temperatures, we determine the enthalpies of vaporization of primary biomass-burning organic aerosols. Further, the developed model allows for evaluating the evolution of oxidation products of the semi-volatile and volatile precursors with aging. More than 30 000 box-model simulations were performed to retrieve the combination of parameters that best fit the observed organic aerosol mass and O : C ratios. The parameters investigated include the NTVOC reaction rates and yields as well as enthalpies of vaporization and the O : C of secondary organic aerosol surrogates. Our results suggest an average ratio of NTVOCs to the sum of non-volatile and semi-volatile organic compounds of ˜ 4.75. The mass yields of these compounds determined for a wide range of atmospherically relevant temperatures and organic aerosol (OA) concentrations were predicted to vary between 8 and 30 % after 5 h of continuous aging. Based on the reaction scheme used, reaction rates of the NTVOC mixture range from 3.0 × 10-11 to 4. 0 × 10-11 cm3 molec-1 s-1. The average enthalpy of vaporization of secondary organic aerosol

  1. Testing fireproof materials in a combustion chamber

    NASA Astrophysics Data System (ADS)

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

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

  2. Testing fireproof materials in a combustion chamber

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  3. SONTRAC: A solar neutron track chamber detector

    NASA Technical Reports Server (NTRS)

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

  4. The Analysis of Ionization Chambers Used for Detecting Smoke Particles

    NASA Astrophysics Data System (ADS)

    Turlej, Z. (Bish).

    Ionization type cells using a radioactive source of primary ions have been used as fire detectors for many years. They have proven sufficiently sensitive to give an alarm when exposed to the relatively small concentration of smoke particles that occur during the early stages of combustion when control of a fire is still possible. In this work the charging of smoke particles in ionization chambers such as typically employed in ionization smoke detectors are investigated theoretically and experimentally. The ionization chambers investigated in this work have parallel plate and spherical electrode geometries. In the absence of smoke particles, the ionization chambers were operated at some ambient electrode current, which depends upon the ion generation rate, the electrode geometries, the potential difference between the electrodes, and the thermodynamic properties of the gas within the chamber volume. When smoke particles are introduced into the ionization chamber they act as an additional sink for the ions, so that the ion current is reduced. The smoke particles in the experiment performed in this work were transferred from the particle generator to the volume surrounding the ionization chamber and allowed to diffuse inside the ionization chamber. An Aitken nuclei counter was employed to measure the concentration of smoke particles inside the ionization chamber. The electric current flowing through the ionization chamber was recorded as a function of time and concentration of the smoke particles inside the chamber. The current loss due to the particles present inside the chamber was calculated and compared with the experimental results. It was found that at the certain level of ambient electrode current, the current loss due to the smoke particles assumes a maximum value. This optimum operating electrode current was predicted by the mathematical model employed in this work. In the light of this model experimental ionization chambers of both parallel and spherical

  5. High counting rate resistive-plate chamber

    NASA Astrophysics Data System (ADS)

    Peskov, V.; Anderson, D. F.; Kwan, S.

    1993-05-01

    Parallel-plate avalanche chambers (PPAC) are widely used in physics experiments because they are fast (less than 1 ns) and have very simple construction: just two parallel metallic plates or mesh electrodes. Depending on the applied voltage they may work either in spark mode or avalanche mode. The advantage of the spark mode of operation is a large signal amplitude from the chamber, the disadvantage is that there is a large dead time (msec) for the entire chamber after an event. The main advantage of the avalanche mode is high rate capability 10(exp 5) counts/mm(sup 2). A resistive-plate chamber (RPC) is similar to the PPAC in construction except that one or both of the electrodes are made from high resistivity (greater than 10(exp 10) Omega(cm) materials. In practice RPC's are usually used in the spark mode. Resistive electrodes are charged by sparks, locally reducing the actual electric field in the gap. The size of the charged surface is about 10 mm(sup 2), leaving the rest of the detector unaffected. Therefore, the rate capability of such detectors in the spark mode is considerably higher than conventional spark counters. Among the different glasses tested the best results were obtained with electron type conductive glasses, which obey Ohm's law. Most of the work with such glasses was done with high pressure parallel-plate chambers (10 atm) for time-of-flight measurements. Resistive glasses have been expensive and produced only in small quantities. Now resistive glasses are commercially available, although they are still expensive in small scale production. From the positive experience of different groups working with the resistive glasses, it was decided to review the old idea to use this glass for the RPC. This work has investigated the possibility of using the RPC at 1 atm and in the avalanche mode. This has several advantages: simplicity of construction, high rate capability, low voltage operation, and the ability to work with non-flammable gases.

  6. 63. Interior view, kitchen chamber, north elevation. The kitchen chamber ...

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

    63. Interior view, kitchen chamber, north elevation. The kitchen chamber was completed in the first stages of phase III construction. The paneled wall to the fireplace's right displays a phase III molding profile. The mark between the cabinet doors and on the large lower panel indicates the former position of a partition wall. The chimney-breast paneling bears a phase I profile and might have been moved to the room when the fireplace mass in the hall was reduced. - John Bartram House & Garden, House, 54th Street & Lindbergh Boulevard, Philadelphia, Philadelphia County, PA

  7. Plasma chemistry in wire chambers

    SciTech Connect

    Wise, J.

    1990-05-01

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

  8. Plant growth chamber M design

    NASA Technical Reports Server (NTRS)

    Prince, R. P.; Knott, W. M.

    1986-01-01

    Crop production is just one of the many processes involved in establishing long term survival of man in space. The benefits of integrating higher plants into the overall plan was recognized early by NASA through the Closed Ecological Life Support System (CELSS) program. The first step is to design, construct, and operate a sealed (gas, liquid, and solid) plant growth chamber. A 3.6 m diameter by 6.7 m high closed cylinder (previously used as a hypobaric vessel during the Mercury program) is being modified for this purpose. The chamber is mounted on legs with the central axis vertical. Entrance to the chamber is through an airlock. This chamber will be devoted entirely to higher plant experimentation. Any waste treatment, food processing or product storage studies will be carried on outside of this chamber. Its primary purpose is to provide input and output data on solids, liquids, and gases for single crop species and multiple species production using different nutrient delivery systems.

  9. Iridium-Coated Rhenium Combustion Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

    1994-01-01

    Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

  10. Iridium-Coated Rhenium Combustion Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

    1994-01-01

    Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

  11. The CLAS drift chamber system

    SciTech Connect

    Mestayer, M.D.; Carman, D.S.; Asavaphibhop, B.

    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.

  12. Annular-Cross-Section CFE Chamber

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.

  13. Annular-Cross-Section CFE Chamber

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.

  14. Double window viewing chamber assembly

    NASA Technical Reports Server (NTRS)

    Keller, V. W. (Inventor); Owen, R. B. (Inventor); Elkins, B. R. (Inventor); White, W. T. (Inventor)

    1986-01-01

    A viewing chamber which permits observation of a sample retained therein includes a pair of double window assemblies mounted in opposed openings in the walls thereof so that a light beam can directly enter and exit from the chamber. A flexible mounting arrangement for the outer windows of the window assemblies enables the windows to be brought into proper alignment. An electrical heating arrangement prevents fogging of the outer windows whereas desiccated air in the volume between the outer and inner windows prevents fogging of the latter.

  15. Test chamber for alpha spectrometry

    DOEpatents

    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.

  16. CHAMBERS FERRY ROADLESS AREA, TEXAS.

    USGS Publications Warehouse

    Houser, B.B.; Ryan, George S.

    1984-01-01

    A geologic and geochemical investigation of the Chambers Ferry Roadless Area, Texas was conducted. The area has probable mineral-resource potential for oil and gas and for lignite. No metallic or additional energy resources were identified in the investigation. Detailed analyses of well logs from the vicinity of the Chambers Ferry Roadless Area, in conjunction with seismic data, are necessary to determine if the subsurface stratigraphy and structure are favorable for the accumulation of oil and gas. A shallow drilling program involving coring on a close-space grid is necessary for determination of the rank and continuity of seams of lignitic sediments in the area.

  17. Free Air CO2 Enrichment (FACE) Research Data from the Aspen FACE Experiment (FACTS II)

    DOE Data Explorer

    DOE has conducted trace gas enrichment experiments since the mid 1990s. The FACE Data Management System is a central repository and archive for Free-Air Carbon Dioxide Enrichment (FACE) data, as well as for the related open-top chamber (OTC) experiments. FACE Data Management System is located at DOE’s Carbon Dioxide Information Analysis Center (CDIAC). While the data from the various FACE sites, each one a unique user facility, are centralized at CDIAC, each of the FACE sites presents its own view of its activities and information. For that reason, DOE Data Explorer users are advised to see both the central repository at http://public.ornl.gov/face/index.shtml and the individual home pages of each site. FACTS II, the Aspen FACE Experiment is a multidisciplinary study to assess the effects of increasing tropospheric ozone and carbon dioxide levels on the structure and function of northern forest ecosystems. The Aspen FACE facility is located at the Harshaw Experimental Forest near Rhinelander, Wisconsin. It consists of twelve 30m rings in which the concentrations of carbon dioxide and tropospheric ozone can be controlled. The design provides the ability to assess the effects of these gasses alone, and in combination, on many ecosystem attributes, including growth, leaf development, root characteristics, and soil carbon. Each ring consists of a series of vertical ventpipes which disperse carbon dioxide, ozone or normal air into the center of the ring. This computer controlled system uses signal feedback technology to adjust gas release each second in order to maintain a stable, elevated concentration of carbon dioxide and/or ozone throughout the experimental plot. Because there is no confinement, there is no significant change in the natural, ambient environment other than elevating these trace gas concentrations. [copied from http://aspenface.mtu.edu/index.html] Ring maps, lists of publications, data from the experiments, newsletters, protocol and performance

  18. Lightweight Chambers for Thrust Assemblies

    NASA Technical Reports Server (NTRS)

    Elam, Sandra K.; Lee, Jonathan; Holmes, Richard; Zimmerman, Frank; Effinger, Mike; Turner, James E. (Technical Monitor)

    2001-01-01

    The Marshall Space Flight Center (MSFC) of the National Aeronautics and Space Administration (NASA) has successfully applied new materials and fabrication techniques to create actively cooled thrust chambers that operate 200-400 degrees hotter and weigh 50% lighter than conventional designs. In some vehicles, thrust assemblies account for as much as 20% of the engine weight. So, reducing the weight of these components and increasing their operating range will benefit many engines and vehicle designs, including Reusable Launch Vehicle (RLV) concepts. Obviously, copper and steel alloys have been used successfully for many years in the chamber components of thrust assemblies. Yet, by replacing the steel alloys with Polymer Matrix Composite (PMC) and/or Metal Matrix Composite (MMC) materials, design weights can be drastically reduced. In addition, replacing the traditional copper alloys with a Ceramic Matrix Composite (CMC) or an advanced copper alloy (Cu-8Cr-4Nb, also known as GRCop-84) significantly increases allowable operating temperatures. Several small MMC and PMC demonstration chambers have recently been fabricated with promising results. Each of these designs included GRCop-84 for the cooled chamber liner. These units successfully verified that designs over 50% lighter are feasible. New fabrication processes, including advanced casting technology and a low cost vacuum plasma spray (VPS) process, were also demonstrated with these units. Hot-fire testing at MSFC is currently being conducted on the chambers to verify increased operating temperatures available with the GRCop-84 liner. Unique CMC chamber liners were also successfully fabricated and prepared for hot-fire testing. Yet, early results indicate these CMC liners need significantly more development in order to use them in required chamber designs. Based on the successful efforts with the MMC and PMC concepts, two full size "lightweight" chambers are currently being designed and fabricated for hot

  19. Lightweight Chambers for Thrust Assemblies

    NASA Technical Reports Server (NTRS)

    Elam, Sandra K.; Lee, Jonathan; Holmes, Richard; Zimmerman, Frank; Effinger, Mike; Turner, James E. (Technical Monitor)

    2001-01-01

    The Marshall Space Flight Center (MSFC) of the National Aeronautics and Space Administration (NASA) has successfully applied new materials and fabrication techniques to create actively cooled thrust chambers that operate 200-400 degrees hotter and weigh 50% lighter than conventional designs. In some vehicles, thrust assemblies account for as much as 20% of the engine weight. So, reducing the weight of these components and increasing their operating range will benefit many engines and vehicle designs, including Reusable Launch Vehicle (RLV) concepts. Obviously, copper and steel alloys have been used successfully for many years in the chamber components of thrust assemblies. Yet, by replacing the steel alloys with Polymer Matrix Composite (PMC) and/or Metal Matrix Composite (MMC) materials, design weights can be drastically reduced. In addition, replacing the traditional copper alloys with a Ceramic Matrix Composite (CMC) or an advanced copper alloy (Cu-8Cr-4Nb, also known as GRCop-84) significantly increases allowable operating temperatures. Several small MMC and PMC demonstration chambers have recently been fabricated with promising results. Each of these designs included GRCop-84 for the cooled chamber liner. These units successfully verified that designs over 50% lighter are feasible. New fabrication processes, including advanced casting technology and a low cost vacuum plasma spray (VPS) process, were also demonstrated with these units. Hot-fire testing at MSFC is currently being conducted on the chambers to verify increased operating temperatures available with the GRCop-84 liner. Unique CMC chamber liners were also successfully fabricated and prepared for hot-fire testing. Yet, early results indicate these CMC liners need significantly more development in order to use them in required chamber designs. Based on the successful efforts with the MMC and PMC concepts, two full size "lightweight" chambers are currently being designed and fabricated for hot

  20. The Outdoor Atmospheric Simulation Chamber of Orleans-France (HELIOS)

    NASA Astrophysics Data System (ADS)

    Mellouki, A.; Véronique, D.; Grosselin, B.; Peyroux, F.; Benoit, R.; Ren, Y.; Idir, M.

    2016-12-01

    Atmospheric simulation chambers are among the most advanced tools for investigating the atmospheric processes to derive physico-chemical parameters which are required for air quality and climate models. Recently, the ICARE-CNRS at Orléans (France) has set up a new large outdoor simulation chamber, HELIOS. HELIOS is one of the most advanced simulation chambers in Europe. It is one of the largest outdoor chambers and is especially suited to processes studies performed under realistic atmospheric conditions. HELIOS is a large hemispherical outdoor simulation chamber (volume of 90 m3) positioned on the top of ICARE-CNRS building at Orléans (47°50'18.39N; 1°56'40.03E). The chamber is made of FEP film ensuring more than 90 % solar light transmission. The chamber is protected against severe meteorological conditions by a moveable "box" which contains a series of Xenon lamps enabling to conduct experiments using artificial light. This special design makes HELIOS a unique platform where experiments can be made using both types of irradiations. HELIOS is dedicated mainly to the investigation of the chemical processes under different conditions (sunlight, artificial light and dark). The platform allows conducting the same type of experiments under both natural and artificial light irradiation. The available large range of complementary and highly sensitive instruments allows investigating the radical chemistry, gas phase processes and aerosol formation under realistic conditions. The characteristics of HELIOS will be presented as well as the first series of experimental results obtained so far.

  1. Characterization and testing of a new environmental chamber

    NASA Astrophysics Data System (ADS)

    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.

  2. Characterization of Wall Loss in an Indoor Smog Chamber

    NASA Astrophysics Data System (ADS)

    Dowdell, T. M.; Smith, D. M.; Fiddler, M. N.; Sexton, K.; Bililign, S.

    2016-12-01

    Indoor smog chambers are customarily used to produce a controlled atmosphere accommodating distinctive particles. A complicating aspect of interpreting data for an experiment that incorporates the use of an indoor smog chamber is determining the wall loss of the particles and gases that make up the controlled atmosphere. To characterize the relative wall losses of different components of the test mixtures within the indoor smog chamber, experiments looking at the concentration-time series of soot and relevant gases will be performed. NOx and ozone are commonly used as these gases because they are the main gas components found in the atmosphere. The NOx and ozone will be injected into the 9.01 m3, or 9,010 L, FEP Teflon-lined indoor smog chamber individually with room lights turned off to minimize chemical reactions. A non-reactive gas, benzene, will also be injected into the chamber as a trace gas. These gases are monitored using a Gas Chromatograph, Ozone Analyzer, and NOx Analyzer. NOx or ozone should show a small-scale decay in the concentration-time series graph, indicating that there is minimal wall loss. If there is a measurable difference in decay compared to the concentration-time series graph of the benzene, then the difference is the wall loss for these gases. Wall loss decays are affected by temperature and relative humidity, which will measured. Evaluating the wall loss as it pertains to various soot particles will be the end-goal. Some concentration decay is going to occur due to dilution, which can be estimated by summing the sampling flow rates and considering the chamber volume. Benzene concentration decays larger than predicted by dilution indicates that the chamber leaks which would need to be corrected. It is important to characterize wall losses so that it can be properly accounted for in any future experiments.The authors acknowledge the support from the National Science Foundation through Grant Number NSF-AGS-1555479

  3. Isotopic probes for chamber-based microphysics studies

    NASA Astrophysics Data System (ADS)

    Moyer, E. J.; Möhler, O.; Ebert, V.; Morong, C. P.

    2008-12-01

    Measurements of the isotopic composition of water vapor are an underutilized potential probe of processes of ice crystal nucleation and growth and cirrus cloud evolution. We discuss a new laser- based absorption spectroscopy instrument for measurement of gas-phase water isotopologues (H2O, HDO, and H218O) currently under construction for use at the AIDA aerosol and cloud chamber in Karlsruhe, Germany, the largest such facility in the world and the only one suitable for isotopic measurements. We discuss proposed chamber experiments and show how isotopic measurements can help discriminate between many current hypotheses proposed to explain observed high supersaturation in cold cirrus, which include inactivation of aerosols by glassification, growth inhibition due to aerosol coating with organic material, ice in cubic rather than hexagonal phase, unexpectedly low temperature-dependent mass accommodation coefficients, and NAT deposition on ice. Chamber experiments offer several advantages over field sampling in the atmosphere from aircraft. First, the limitations of natural isotopic ratios (1:10000 for HDO:H2O) are not a constraint in controlled chamber experiments, because chamber water can be doped to reduce the difference between concentrations of common and rare isotopologues and allow increased measurement sensitivity. Second, different water sources can be isotopically labeled, allowing explicit measurement of fluxes. The combination allows the use of isotopic probes in novel ways for understanding microphysics in cold cirrus.

  4. Development of a Dry Wall Concept for Laser IFE Chambers

    SciTech Connect

    Blanchard, James P.; Martin, Carl J.

    2005-04-15

    The first wall of a laser fusion chamber will experience high heat loads pulsed at 5-10 Hz with pulse widths on the order of a few microseconds. This poses a challenging problem for dry wall designs, as the wall will be susceptible to a variety of failure modes. The primary design concept of the High Average Power Laser (HAPL) project is a ferritic steel first wall coated with tungsten armor. Due to the extreme heat loads, the armor will experience high temperatures, extensive yielding, and surface cracking. In order to evaluate the ability of this design to provide a suitable lifetime, a series of experiments to simulate chamber conditions using ions, x-rays, infrared heating, and lasers is under way. These experimental efforts have been coupled with numerical modeling to help determine likely failure modes and establish design criteria for chambers. This paper compares models for the thermomechanical effects seen in the tests to those expected in a full power chamber, in order to assess the ability of the tests to mimic the actual chamber performance. The tests are found to have some limitations, but they still offer excellent approximations of the true behavior.

  5. Simulation of Layered Magma Chambers.

    ERIC Educational Resources Information Center

    Cawthorn, Richard Grant

    1991-01-01

    The principles of magma addition and liquid layering in magma chambers can be demonstrated by dissolving colored crystals. The concepts of density stratification and apparent lack of mixing of miscible liquids is convincingly illustrated with hydrous solutions at room temperature. The behavior of interstitial liquids in "cumulus" piles…

  6. Nondestructive test of regenerative chambers

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Stauffis, R.; Wood, R.

    1972-01-01

    Flat panels simulating internally cooled regenerative thrust chamber walls were fabricated by electroforming, brazing and diffusion bonding to evaluate the feasibility of nondestructive evaluation techniques to detect bonds of various strength integrities. Ultrasonics, holography, and acoustic emission were investigated and found to yield useful and informative data regarding the presence of bond defects in these structures.

  7. Simulation of Layered Magma Chambers.

    ERIC Educational Resources Information Center

    Cawthorn, Richard Grant

    1991-01-01

    The principles of magma addition and liquid layering in magma chambers can be demonstrated by dissolving colored crystals. The concepts of density stratification and apparent lack of mixing of miscible liquids is convincingly illustrated with hydrous solutions at room temperature. The behavior of interstitial liquids in "cumulus" piles…

  8. Chamber Music for Better Bands.

    ERIC Educational Resources Information Center

    Brown, Michael R.

    1998-01-01

    Considers why students should participate in a chamber music ensemble: (1) students develop a sense of collegiality and self-worth; (2) ensembles encourage practice time; and (3) ensembles provide flexible performance opportunities. Highlights the different aspects of creating an ensemble from the availability of faculty to selecting challenging…

  9. Chamber Clearing First Principles Modeling

    SciTech Connect

    Loosmore, G

    2009-06-09

    LIFE fusion is designed to generate 37.5 MJ of energy per shot, at 13.3 Hz, for a total average fusion power of 500 MW. The energy from each shot is partitioned among neutrons ({approx}78%), x-rays ({approx}12%), and ions ({approx}10%). First wall heating is dominated by x-rays and debris because the neutron mean free path is much longer than the wall thickness. Ion implantation in the first wall also causes damage such as blistering if not prevented. To moderate the peak-pulse heating, the LIFE fusion chamber is filled with a gas (such as xenon) to reduce the peak-pulse heat load. The debris ions and majority of the x-rays stop in the gas, which re-radiates this energy over a longer timescale (allowing time for heat conduction to cool the first wall sufficiently to avoid damage). After a shot, because of the x-ray and ion deposition, the chamber fill gas is hot and turbulent and contains debris ions. The debris needs to be removed. The ions increase the gas density, may cluster or form aerosols, and can interfere with the propagation of the laser beams to the target for the next shot. Moreover, the tritium and high-Z hohlraum debris needs to be recovered for reuse. Additionally, the cryogenic target needs to survive transport through the gas mixture to the chamber center. Hence, it will be necessary to clear the chamber of the hot contaminated gas mixture and refill it with a cool, clean gas between shots. The refilling process may create density gradients that could interfere with beam propagation, so the fluid dynamics must be studied carefully. This paper describes an analytic modeling effort to study the clearing and refilling process for the LIFE fusion chamber. The models used here are derived from first principles and balances of mass and energy, with the intent of providing a first estimate of clearing rates, clearing times, fractional removal of ions, equilibrated chamber temperatures, and equilibrated ion concentrations for the chamber. These can be used

  10. Quantification of static magnetic field effects on radiotherapy ionization chambers.

    PubMed

    Agnew, J; O'Grady, F; Young, R; Duane, S; Budgell, G J

    2017-03-07

    Integrated magnetic resonance (MR) imaging and radiotherapy (RT) delivery machines are currently being developed, with some already in clinical use. It is anticipated that the strong magnetic field used in some MR-RT designs will have a significant impact on routine measurements of dose in the MR-linac performed using ionization chambers, which provide traceability back to a primary standard definition of dose. In particular, the presence of small air gaps around ionization chambers may introduce unacceptably high uncertainty into these measurements. In this study, we investigate and quantify the variation attributable to air gaps for several routinely-used cylindrical ionization chambers in a magnetic field, as well as the effect of the magnetic field alone on the response of the chambers. The measurements were performed in a Co-60 beam, while the ionization chambers were positioned in custom-made Perspex phantoms between the poles of an electromagnet, which was capable of generating magnetic fields of up to 2 T field strength, although measurements were focused around 1.5 T. When an asymmetric air gap was rotated at cardinal angles around the ionization chambers investigated here, variation of up to 8.5  ±  0.2 percentage points (PTW 31006 chamber) was observed in an applied magnetic field of 1.5 T. The minimum peak-to-peak variation was 1.1  ±  0.1% (Exradin A1SL). When the same experiment was performed with a well-defined air gap of known position using the PTW 30013 chamber, a variation of 3.8  ±  0.2% was observed. When water was added to the phantom cavity to eliminate all air gaps, the variation for the PTW 30013 was reduced to 0.2  ±  0.01%.

  11. Quantification of static magnetic field effects on radiotherapy ionization chambers

    NASA Astrophysics Data System (ADS)

    Agnew, J.; O’Grady, F.; Young, R.; Duane, S.; Budgell, G. J.

    2017-03-01

    Integrated magnetic resonance (MR) imaging and radiotherapy (RT) delivery machines are currently being developed, with some already in clinical use. It is anticipated that the strong magnetic field used in some MR-RT designs will have a significant impact on routine measurements of dose in the MR-linac performed using ionization chambers, which provide traceability back to a primary standard definition of dose. In particular, the presence of small air gaps around ionization chambers may introduce unacceptably high uncertainty into these measurements. In this study, we investigate and quantify the variation attributable to air gaps for several routinely-used cylindrical ionization chambers in a magnetic field, as well as the effect of the magnetic field alone on the response of the chambers. The measurements were performed in a Co-60 beam, while the ionization chambers were positioned in custom-made Perspex phantoms between the poles of an electromagnet, which was capable of generating magnetic fields of up to 2 T field strength, although measurements were focused around 1.5 T. When an asymmetric air gap was rotated at cardinal angles around the ionization chambers investigated here, variation of up to 8.5  ±  0.2 percentage points (PTW 31006 chamber) was observed in an applied magnetic field of 1.5 T. The minimum peak-to-peak variation was 1.1  ±  0.1% (Exradin A1SL). When the same experiment was performed with a well-defined air gap of known position using the PTW 30013 chamber, a variation of 3.8  ±  0.2% was observed. When water was added to the phantom cavity to eliminate all air gaps, the variation for the PTW 30013 was reduced to 0.2  ±  0.01%.

  12. Theoretical study of energy deposition in ionization chambers for tritium measurements

    SciTech Connect

    Chen, Zhilin; Peng, Shuming; Meng, Dan; He, Yuehong; Wang, Heyi

    2013-10-15

    Energy deposition in ionization chambers has been theoretically studied for tritium measurements in gaseous form. A one-dimension model is introduced to establish the quantitative relationship between energy deposition rate and many factors, including carrier gas, gas pressure, wall material, chamber size, and gas temperature. Energy deposition rate has been calculated at pressure varying from 5 kPa to 500 kPa based on some approximations. It is found that energy deposition rate varies greatly for different parameters, especially at low gas pressure. For the same chamber, energy deposition rate in argon is much higher than in deuterium, as much as 70.7% higher at 5 kPa. Gold plated chamber gives highest energy deposition rate in the calculations while aluminum chamber results in the lowest. As chamber size gets smaller, β ray emitted by tritium will deposit less energy in the sensitive region of the chamber. For chambers flowing through with the same gas, energy deposition rate in a 10 L chamber is 23.9% higher than in a 0.05 L chamber at 5 kPa. Gas temperature also places slight influence on energy deposition rate, and 373 K will lead to 6.7% lower deposition rate than 233 K at 5 kPa. In addition, experiments have been performed to obtain energy deposition rate in a gold plated chamber, which show good accordance with theoretical calculations.

  13. Theoretical study of energy deposition in ionization chambers for tritium measurements

    NASA Astrophysics Data System (ADS)

    Chen, Zhilin; Peng, Shuming; Meng, Dan; He, Yuehong; Wang, Heyi

    2013-10-01

    Energy deposition in ionization chambers has been theoretically studied for tritium measurements in gaseous form. A one-dimension model is introduced to establish the quantitative relationship between energy deposition rate and many factors, including carrier gas, gas pressure, wall material, chamber size, and gas temperature. Energy deposition rate has been calculated at pressure varying from 5 kPa to 500 kPa based on some approximations. It is found that energy deposition rate varies greatly for different parameters, especially at low gas pressure. For the same chamber, energy deposition rate in argon is much higher than in deuterium, as much as 70.7% higher at 5 kPa. Gold plated chamber gives highest energy deposition rate in the calculations while aluminum chamber results in the lowest. As chamber size gets smaller, β ray emitted by tritium will deposit less energy in the sensitive region of the chamber. For chambers flowing through with the same gas, energy deposition rate in a 10 L chamber is 23.9% higher than in a 0.05 L chamber at 5 kPa. Gas temperature also places slight influence on energy deposition rate, and 373 K will lead to 6.7% lower deposition rate than 233 K at 5 kPa. In addition, experiments have been performed to obtain energy deposition rate in a gold plated chamber, which show good accordance with theoretical calculations.

  14. Promoted-Combustion Chamber with Induction Heating Coil

    NASA Technical Reports Server (NTRS)

    Richardson, Erin; Hagood, Richard; Lowery, Freida; Herald, Stephen

    2006-01-01

    An improved promoted-combustion system has been developed for studying the effects of elevated temperatures on the flammability of metals in pure oxygen. In prior promoted-combustion chambers, initial temperatures of metal specimens in experiments have been limited to the temperatures of gas supplies, usually near room temperature. Although limited elevated temperature promoted-combustion chambers have been developed using water-cooled induction coils for preheating specimens, these designs have been limited to low-pressure operation due to the hollow induction coil. In contrast, the improved promoted-combustion chamber can sustain a pressure up to 10 kpsi (69 MPa) and, through utilization of a solid induction coil, is capable of preheating a metal specimen up to its melting point [potentially in excess of 2,000 F (approximately equal to 1,100 C)]. Hence, the improved promoted combustion chamber makes a greater range of physical conditions and material properties accessible for experimentation. The chamber consists of a vertical cylindrical housing with an inner diameter of 8 in. (20.32 cm) and an inner height of 20.4 in. (51.81 cm). A threaded, sealing cover at one end of the housing can be unscrewed to gain access for installing a specimen. Inlet and outlet ports for gases are provided. Six openings arranged in a helical pattern in the chamber wall contain sealed sapphire windows for viewing an experiment in progress. The base of the chamber contains pressure-sealed electrical connectors for supplying power to the induction coil. The connectors feature a unique design that prevents induction heating of the housing and the pressure sealing surfaces; this is important because if such spurious induction heating were allowed to occur, chamber pressure could be lost. The induction coil is 10 in. (25.4 cm) long and is fitted with a specimen holder at its upper end. At its lower end, the induction coil is mounted on a ceramic base, which affords thermal insulation to

  15. Viscoplastic analysis of an experimental cylindrical thrust chamber liner

    NASA Technical Reports Server (NTRS)

    Arya, Vinod K.; Arnold, Steven M.

    1991-01-01

    A viscoplastic stress-strain analysis of an experimental cylindrical thrust chamber is presented. A viscoelastic constitutive model incorporating a single internal state variable that represents kinematic hardening was employed to investigate whether such a viscoplastic model could predict the experimentally observed behavior of the thrust chamber. Two types of loading cycles were considered: a short cycle of 3.5 sec. duration that corresponded to the experiments, and an extended loading cycle of 485.1 sec. duration that is typical of the Space Shuttle Main Engine (SSME) operating cycle. The analysis qualitatively replicated the deformation behavior of the component as observed in experiments designed to simulate SSME operating conditions. The analysis also showed that the mode and location in the component may depend on the loading cycle. The results indicate that using viscoplastic models for structural analysis can lead to a more realistic life assessment of thrust chambers.

  16. Plasma chamber testing of advanced photovoltaic solar array coupons

    NASA Astrophysics Data System (ADS)

    Hillard, G. Barry

    1994-05-01

    The solar array module plasma interactions experiment is a space shuttle experiment designed to investigate and quantify the high voltage plasma interactions. One of the objectives of the experiment is to test the performance of the Advanced Photovoltaic Solar Array (APSA). The material properties of array blanket are also studied as electric insulators for APSA arrays in high voltage conditions. Three twelve cell prototype coupons of silicon cells were constructed and tested in a space simulation chamber.

  17. Emulsion chamber observations and interpretation (HE 3)

    NASA Technical Reports Server (NTRS)

    Shibata, M.

    1986-01-01

    Experimental results from Emulsion Chamber (EC) experiments at mountain altitudes or at higher levels using flying carriers are examined. The physical interest in this field is concentrated on the strong interaction at the very high energy region exceeding the accelerator energy, also on the primary cosmic ray intensity and its chemical composition. Those experiments which observed cosmic ray secondaries gave information on high energy interaction characteristics through the analyses of secondary spectra, gamma-hadron families and C-jets (direct observation of the particle production occuring at the carbon target). Problems of scaling violation in fragmentation region, interaction cross section, transverse momentum of produced secondaries, and some peculiar features of exotic events are discussed.

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

    NASA Astrophysics Data System (ADS)

    Szydagis, Matthew Mark

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

  19. Dark matter limits froma 15 kg windowless bubble chamber

    SciTech Connect

    Szydagis, Matthew Mark

    2011-03-01

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

  20. Design considerations of a thermally stabilized continuous flow electrophoresis chamber 2

    NASA Technical Reports Server (NTRS)

    Jandebeur, T. S.

    1982-01-01

    The basic adjustable parameters of a Beckman Continouous Particle Electrophoresis (CPE) Apparatus are investigated to determine the optimum conditions for ground based operation for comparison with space experiments. The possible application of electrically insulated copper/aluminum chamber walls is evaluated as a means to thermally stabilize or equilibrate lateral temperature gradients which exist on the walls of conventional plastic chambers and which distort the rectilinear base flow of buffer through the chamber, significantly affecting sample resolution.

  1. SPRUCE experiment data infrastructure

    NASA Astrophysics Data System (ADS)

    Krassovski, M.; Hanson, P. J.; Boden, T.; Riggs, J.; Nettles, W. R.; Hook, L. A.

    2013-12-01

    The Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL), USA has provided scientific data management support for the US Department of Energy and international climate change science since 1982. Among the many data activities CDIAC performs are design and implementation of the data systems. One current example is the data system and network for SPRUCE experiment. The SPRUCE experiment (http://mnspruce.ornl.gov) is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. Experimental work in the 8.1-ha S1 bog will be a climate change manipulation focusing on the combined responses to multiple levels of warming at ambient or elevated CO2 (eCO2) levels. The experiment provides a platform for testing mechanisms controlling the vulnerability of organisms, biogeochemical processes and ecosystems to climatic change (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity, the cycling and release of CO2 and CH4 to the atmosphere). The manipulation will evaluate the response of the existing biological communities to a range of warming levels from ambient to +9°C, provided via large, modified open-top chambers. The ambient and +9°C warming treatments will also be conducted at eCO2 (in the range of 800 to 900 ppm). Both direct and indirect effects of these experimental perturbations will be analyzed to develop and refine models needed for full Earth system analyses. SPRUCE provides wide range continuous and discrete measurements. To successfully manage SPRUCE data flow

  2. A recording chamber for small volume slice electrophysiology

    PubMed Central

    Quinn, Kevin D.; Cruickshank-Quinn, Charmion I.; Reisdorph, Nichole; Lei, Tim C.; Klug, Achim

    2015-01-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products. PMID:26203105

  3. Initial Back-to-Back Fission Chamber Testing in ATRC

    SciTech Connect

    Benjamin Chase; Troy Unruh; Joy Rempe

    2014-06-01

    Development and testing of in-pile, real-time neutron sensors for use in Materials Test Reactor experiments is an ongoing project at Idaho National Laboratory. The Advanced Test Reactor National Scientific User Facility has sponsored a series of projects to evaluate neutron detector options in the Advanced Test Reactor Critical Facility (ATRC). Special hardware was designed and fabricated to enable testing of the detectors in the ATRC. Initial testing of Self-Powered Neutron Detectors and miniature fission chambers produced promising results. Follow-on testing required more experiment hardware to be developed. The follow-on testing used a Back-to-Back fission chamber with the intent to provide calibration data, and a means of measuring spectral indices. As indicated within this document, this is the first time in decades that BTB fission chambers have been used in INL facilities. Results from these fission chamber measurements provide a baseline reference for future measurements with Back-to-Back fission chambers.

  4. Photochemistry of Glyoxal in Wet Aerosols: Smog Chamber Study

    NASA Astrophysics Data System (ADS)

    Lim, Y. B.; Kim, H.; Turpin, B. J.

    2015-12-01

    Aqueous chemistry is an important pathway for the formation of secondary organic aerosol (SOA). Reaction vessel studies provide evidence that in the aqueous phase photooxidation of water soluble organic compounds (e.g., glyoxal, methylglyoxal) form multifunctional organic products and oligomers. In this work, we extend this bulk-phase chemistry to the condensed-phase chemistry that occurs in/on aerosols by conducting smog chamber experiments — photooxidation of ammonium sulfate and sulfuric acid aerosols containing glyoxal and hydrogen peroxide in the presence of NOx under dry/humid conditions. Particles were analyzed using ultra performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). In the irradiated chamber, photooxidation products of glyoxal as seen in reaction vessel experiments (e.g., oxalic acids and tartaric acids) were also formed in both ammonium sulfate aerosols and sulfuric acid aerosols at humid and even dry conditions. However, the major products were organosulfurs (CHOS), organonitrogens (CHON), and nitrooxy-organosulfates (CHONS), which were also dominantly formed in the dark chamber. These products were formed via non-radical reactions, which depend on acidity and humidity. However, the real-time profiles in the dark chamber and the irradiated chamber were very different, suggesting photochemistry substantially affects non-radical formation in the condensed phase.

  5. Single wire drift chamber design

    SciTech Connect

    Krider, J.

    1987-03-30

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

  6. Evaluation of Impinging Stream Vortex Chamber Concepts for Liquid Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.; Bullard, Brad; Kopicz, Charles; Michaels, Scott

    2002-01-01

    for the liquid oxygen (LOX) hydrocarbon fuel (RP-1) system has been derived from the one for the gel propellant. An unlike impinging injector was employed to deliver the propellants to the chamber. MSFC is also conducting an alternative injection scheme, called the chasing injector, associated with this vortex chamber concept. In this injection technique, both propellant jets and their impingement point are in the same chamber cross-sectional plane. Long duration tests (approximately up to 15 seconds) will be conducted on the ISVC to study the thermal effects. This paper will report the progress of the subject efforts at NASA Marshall Space Flight Center. Thrust chamber performance and thermal wall compatibility will be evaluated. The chamber pressures, wall temperatures, and thrust will be measured as appropriate. The test data will be used to validate CFD models, which, in turn, will be used to design the optimum vortex chambers. Measurements in the previous tests showed that the chamber pressures vary significantly with radius. This is due to the existence of the vortices in the chamber flow field. Hence, the combustion efficiency may not be easily determined from chamber pressure. For this project, measured thrust data will be collected. The performance comparison will be in terms of specific impulse efficiencies. In addition to the thrust measurements, several pressure and temperature readings at various locations on the chamber head faceplate and the chamber wall will be made. The first injector and chamber were designed and fabricated based on the available data and experience gained during gel propellant system tests by the U.S. Army. The alternate injector for the ISVC was also fabricated. Hot-fire tests of the vortex chamber are about to start and are expected to complete in February of 2003 at the TS115 facility of MSFC.

  7. Evaluation of Impinging Stream Vortex Chamber Concepts for Liquid Rocket Engine Applications

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.; Bullard, Brad; Kopicz, Charles; Michaels, Scott

    2002-01-01

    for the liquid oxygen (LOX) hydrocarbon fuel (RP-1) system has been derived from the one for the gel propellant. An unlike impinging injector was employed to deliver the propellants to the chamber. MSFC is also conducting an alternative injection scheme, called the chasing injector, associated with this vortex chamber concept. In this injection technique, both propellant jets and their impingement point are in the same chamber cross-sectional plane. Long duration tests (approximately up to 15 seconds) will be conducted on the ISVC to study the thermal effects. This paper will report the progress of the subject efforts at NASA Marshall Space Flight Center. Thrust chamber performance and thermal wall compatibility will be evaluated. The chamber pressures, wall temperatures, and thrust will be measured as appropriate. The test data will be used to validate CFD models, which, in turn, will be used to design the optimum vortex chambers. Measurements in the previous tests showed that the chamber pressures vary significantly with radius. This is due to the existence of the vortices in the chamber flow field. Hence, the combustion efficiency may not be easily determined from chamber pressure. For this project, measured thrust data will be collected. The performance comparison will be in terms of specific impulse efficiencies. In addition to the thrust measurements, several pressure and temperature readings at various locations on the chamber head faceplate and the chamber wall will be made. The first injector and chamber were designed and fabricated based on the available data and experience gained during gel propellant system tests by the U.S. Army. The alternate injector for the ISVC was also fabricated. Hot-fire tests of the vortex chamber are about to start and are expected to complete in February of 2003 at the TS115 facility of MSFC.

  8. Space Chambers for Crop Treatment

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Vacuum chambers, operated by McDonnell Douglas Corporation to test spacecraft, can also be used to dry water-soaked records. The drying temperature is low enough to allow paper to dry without curling or charging. Agricultural crops may also be dried using a spinoff system called MIVAC, which has proven effective in drying rice, wheat, soybeans, corn, etc. The system is energy efficient and can incorporate a sanitation process for destroying insects without contamination.

  9. 21 CFR 868.5470 - Hyperbaric chamber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... than atmospheric pressure. This device does not include topical oxygen chambers for extremities (§ 878... hyperbaric chamber is a device that is intended to increase the environmental oxygen pressure to promote...

  10. NASA Goddard's Acoustic Test Chamber

    NASA Image and Video Library

    2017-09-28

    At Goddard, the engineers use the Acoustic Test Chamber, a 42-foot-tall chamber, with 6-foot-diameter speaker horns to replicate the launch environment. The horns use an altering flow of gaseous nitrogen to produce a sound level as high as 150 decibels for two-minute tests. That’s about the level of sound heard standing next to a jet engine during takeoff. The 6-foot-wide horns in this 42-foot-tall chamber can produce noise at levels as high as 150 dB. During the acoustics test, the speakers can still be heard outside of its insulated massive metal doors. Credits: NASA/Goddard/Chris Gunn NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  11. Rocket Engine Thrust Chamber Assembly

    NASA Technical Reports Server (NTRS)

    Cornelius, Charles S. (Inventor); Counts, Richard H. (Inventor); Myers, W. Neill (Inventor); Lackey, Jeffrey D. (Inventor); Peters, Warren (Inventor); Shadoan, Michael (Inventor); Sparks, David L. (Inventor); Lawrence, Timothy W. (Inventor)

    2001-01-01

    A thrust chamber assembly for liquid fueled rocket engines and the method of making it wherein a two-piece mandrel having the configuration of an assembly having a combustion chamber portion connected to a nozzle portion through a throat portion is wrapped with a silica tape saturated with a phenolic resin, the tape extending along the mandrel and covering the combustion chamber portion of the mandrel to the throat portion. The width of the tape is positioned at an angle of 30 to 50 deg. to the axis of the mandrel such that one edge of the tape contacts the mandrel while the other edge is spaced from the mandrel. The phenolic in the tape is cured and the end of the wrap is machined to provide a frusto-conical surface extending at an angle of 15 to 30 deg. with respect to the axis of the mandrel for starting a second wrap on the mandrel to cover the throat portion. The remainder of the mandrel is wrapped with a third silica tape having its width positioned at a angle of 5 to 20 deg. from the axis of the mandrel. The resin in the third tape is cured and the assembly is machined to provide a smooth outer surface. The entire assembly is then wrapped with a tow of graphite fibers wetted with an epoxy resin and, after the epoxy resin is cured, the graphite is machined to final dimensions.

  12. [Security management and maintenance of medical hyperbaric oxygen chamber].

    PubMed

    Nie, ZhuoJun

    2012-03-01

    In this article, based on years of working experience, the author briefly analyzes eight issues for security management and maintenance of medical hyperbaric oxygen chamber, according to the relevant laws, regulations, standards and norms, which can be a reference in this area.

  13. Hadrons registration in emulsion chamber with carbon block

    NASA Technical Reports Server (NTRS)

    Tomaszewski, A.; Wlodarczyk, Z.

    1985-01-01

    Nuclear-electro-magnetic cascade (NEC) in X-ray emulsion chambers with carbon block, which are usually used in the Pamir experiment, was Monte-Carlo simulated. Going over from optical density to Summary E sub gamma is discussed. The hole of NEC in the interpretation of energy spectra is analyzed.

  14. Drift chamber vertex detectors for SLC/LEP

    SciTech Connect

    Hayes, K.G.

    1987-03-01

    The short but measurable lifetimes of the b and c quarks and the tau lepton have motivated the development of high precision tracking detectors capable of providing information on the decay vertex topology of events containing these particles. This paper reviews the OPAL, L3, and MARK II experiments vertex drift chambers.

  15. Assumption Centred Modelling of Ecosystem Responses to CO2 at Six US Atmospheric CO2 Enrichment Experiments.

    NASA Astrophysics Data System (ADS)

    Walker, A. P.; De Kauwe, M. G.; Medlyn, B. E.; Zaehle, S.; Luus, K. A.; Ryan, E.; Xia, J.; Norby, R. J.

    2015-12-01

    Plant photosynthetic rates increase and stomatal apertures decrease in response to elevated atmospheric CO[2] (eCO2), increasing both plant carbon (C) availability and water use efficiency. These physiological responses to eCO2 are well characterised and understood, however the ecological effects of these responses as they cascade through a suite of plant and ecosystem processes are complex and subject to multiple interactions and feedbacks. Therefore the response of the terrestrial carbon sink to increasing atmospheric CO[2] remains the largest uncertainty in global C cycle modelling to date, and is a huge contributor to uncertainty in climate change projections. Phase 2 of the FACE Model-Data Synthesis (FACE-MDS) project synthesises ecosystem observations from five long-term Free-Air CO[2] Enrichment (FACE) experiments and one open top chamber (OTC) experiment to evaluate the assumptions of a suite of terrestrial ecosystem models. The experiments are: The evergreen needleleaf Duke Forest FACE (NC), the deciduous broadleaf Oak Ridge FACE (TN), the prairie heating and FACE (WY), and the Nevada desert FACE, and the evergreen scrub oak OTC (FL). An assumption centered approach is being used to analyse: the interaction between eCO2 and water limitation on plant productivity; the interaction between eCO2 and temperature on plant productivity; whether increased rates of soil decomposition observed in many eCO2 experiments can account for model deficiencies in N uptake shown during Phase 1 of the FACE-MDS; and tracing carbon through the ecosystem to identify the exact cause of changes in ecosystem C storage.

  16. Gas turbine combustion chamber with air scoops

    SciTech Connect

    Mumford, S.E.; Smed, J.P.

    1989-12-19

    This patent describes a gas turbine combustion chamber. It comprises: means for admission of fuel to the upstream end thereof and discharge of hot gases from the downstream end thereof, and a combustion chamber wall, having an outer surface, with apertures therethrough, and air scoops provided through the apertures to direct air into the combustion chamber.

  17. Making a Fish Tank Cloud Chamber

    ERIC Educational Resources Information Center

    Green, Frances

    2012-01-01

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

  18. A Sensitive Cloud Chamber without Radioactive Sources

    ERIC Educational Resources Information Center

    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.)

  19. A Sensitive Cloud Chamber without Radioactive Sources

    ERIC Educational Resources Information Center

    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.)

  20. Making a Fish Tank Cloud Chamber

    ERIC Educational Resources Information Center

    Green, Frances

    2012-01-01

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

  1. Design and construction of an inexpensive homemade plant growth chamber.

    PubMed

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

  2. Design and Construction of an Inexpensive Homemade Plant Growth Chamber

    PubMed Central

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K.; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140–250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

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

    SciTech Connect

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

    2001-02-06

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

  4. Design, simulation and construction of a Wire Chamber electronics

    NASA Astrophysics Data System (ADS)

    Istemihan, Zehra

    2017-02-01

    Tracking charged particles has a wide spectrum of applications in scientific and industrial projects. The Delay Wire Chamber (DWC) is a kind of gaseous detector which is a simpler form of the Multi Wire Proportional Chamber, and was developed by the Beam Instrumentation Group at CERN. It is preferred in accelerator and particle physics experiments because of its ease of use, affordability and durability, and it also provides decent position precision. In this work, we describe the working principles of the readout electronics of a new DWC that is being designed and constructed at our laboratory. Results from the simulation of the circuit and the constructed prototype will be presented.

  5. Smog chamber simulation of Los Angeles pollutant transport

    SciTech Connect

    Glasson, W.A.

    1981-06-01

    A smog chamber study simulated pollutant transport from Los Angeles to downwind areas by irradiating a typical Los Angeles hydrocarbon/nitrogen oxides mixture for extended periods of time. Smog chamber experiments were extended to 22 hr to obtain an integrated light intensity equal to that which occurs in this city. Results show that downwind oxidant levels are only slightly affected by large changes in emissions of nitrogen oxides. However, it is clear that reduced emissions will lead to an increase in oxidant in downtown Los Angeles. (6 graphs, 9 references, 1 table)

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

    NASA Technical Reports Server (NTRS)

    Montz, Mike E.

    2012-01-01

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

  7. Disappearance of fuel hydrazine vapors in fluorocarbon-film environmental chambers. Experimental observations and kinetic modeling

    SciTech Connect

    Stone, D.A.; Wiseman, F.L.; Kilduff, J.E.; Koontz, S.L.; Davis, D.D.

    1989-03-01

    Fluorocarbon-film environmental chambers, of the type often employed in air pollution studies, have been used to investigate the stability of the fuel hydrazines (hydrazine, methylhydrazine, and 1,1-dimethylhydrazine) with respect to atmospheric oxidation. These studies have shown that the observed disappearance of fuel hydrazine vapors in these chambers is caused by physical loss processes rather than oxidation. Vapor-phase decay is affected by chamber size, water content of the matrix gas, and previous chamber experiments. A kinetic model has been developed that incorporates adsorption, permeation, and surface site concentration to fit the observed decay data.

  8. [Effect of Cu2+ on the power output of dual-chamber microbial fuel cell].

    PubMed

    Mu, Shu-Jun; Li, Xiu-Fen; Ren, Yue-Ping; Wang, Xin-Hua

    2014-07-01

    After addition of Cu2+ into the anodic and/or cathodic chamber, the effect of Cu2+ on the internal resistance and its distribution, power output and coulombic efficiency of dual-chamber microbial fuel cell (MFC) was investigated in this manuscript with the aid of analyzing the distribution of copper speciation. It could provide helpful information for correlative research on treatment of copper-containing wastewater by MFC. It showed that the addition of 10 mg x L(-1) Cu2+ into the anodic chamber inhibited the microbial activity, and increased the anodic activation resistance as well as the apparent internal resistance, consequently reduced the power output and coulombic efficiency of the system. However, the addition of 500 mg x L(-1) Cu2+ into the cathodic chamber significantly reduced the cathodic activation resistance as well as the apparent internal resistance, while improved the power output and the coulombic efficiency. Cu2+ in the anodic chamber was not transfered into the cathodic chamber. When adding Cu2+ into the cathodic chamber, it was mainly reduced and deposited on the cathodic chamber. It could also be transferred/diffused to the anodic chamber across the proton exchange membrane (2.8%) because of its concentration difference, thus affecting the microbial activity and power output. Only a small amount of Cu2+ remained in the supernatant of the cathodic chamber at the end of experiment.

  9. Effects of coating rectangular microscopic electrophoresis chamber with methylcellulose

    NASA Technical Reports Server (NTRS)

    Plank, L. D.

    1985-01-01

    One of the biggest problems in obtaining high accuracy in microscopic electrophoresis is the parabolic flow of liquid in the chamber due to electroosmotic backflow during application of the electric field. In chambers with glass walls the source of polarization leading to electroosmosis is the negative charge of the silicare and other ions that form the wall structure. It was found by Hjerten, who used a rotating 3.0 mm capillary tube for free zone electrophoresis, that precisely neutralizing this charge was extremely difficult, but if a neutral polymer matrix (formaldehyde fixed methylcellulose) was formed over the glass (quartz) wall the double layer was displaced and the viscosity at the shear plane increased so that electroosmotic flow could be eliminated. Experiments were designed to determine the reliability with which methylcellulose coating of the Zeiss Cytopherometer chamber reduced electroosmotic backflow and the effect of coating on the accuracy of cell electrophoretic mobility (EPN) determinations. Fixed rat erythrocytes (RBC) were used as test particles.

  10. Spectra, composition, and interactions of nuclei with magnet interaction chambers

    NASA Technical Reports Server (NTRS)

    Parneil, T. A.; Derrickson, J. H.; Fountain, W. F.; Roberts, F. E.; Tabuki, T.; Watts, J. W.; Burnett, T. H.; Cherry, M. C.; Dake, S.; Fuki, M.

    1990-01-01

    Emulsion chambers will be flown in the Astromag Facility to measure the cosmic ray composition and spectra to 10 exp 15 eV total energy and to definitively study the characteristics of nucleus-nucleus interactions above 10 exp 12 eV/n. Two configurations of emulsion chambers will be flown in the SCIN/MAGIC experiment. One chamber has an emulsion target and a calorimeter similar to those recently flown on balloons for composition and spectra measurements. The other has an identical calorimeter and a low-density target section optimized for performing rigidity measurements on charged particles produced in interactions. The transverse momenta of charged and neutral mesons, direct hadronic pairs from resonance decays and interference effects, and possible charge clustering in high-density states of matter will be studied.

  11. Atmosphere contamination following repainting of a human hyperbaric chamber complex

    SciTech Connect

    Lillo, R.S.; Morris, J.W.; Caldwell, J.M.; Balk, D.M.; Flynn, E.T. )

    1990-09-01

    The Naval Medical Research Institute currently conducts hyperbaric research in a Man-Rated Chamber Complex (MRCC) originally installed in 1977. Significant engineering alterations to the MRCC and rusting of some of its interior sections necessitated repainting, which was completed in 1988. Great care was taken in selecting an appropriate paint (polyamide epoxy) and in ensuring correct application and curing procedures. Only very low levels of hydrocarbons were found in the MRCC atmosphere before initial pressurization after painting and curing. After pressurization, however, significant chemical contamination was found. The primary contaminants were aromatic hydrocarbons: xylenes (which were a major component of both the primer and topcoat paint) and ethyl benzene. The role that pressure played in stimulating off-gassing from the paint is not clear; the off-gassing rate was observed to be similar over a large range in chamber pressures from 1.6 to 31.0 atm abs. Scrubbing the chamber atmosphere with the chemical absorbent Purafil was effective in removing the contaminants. Contamination has been observed to slowly decline with chamber use and is expected to continue to improve with time. However, this contamination experience emphasizes the need for a high precision gas analysis program at any diving facility to ensure the safety of the breathing gas and chamber atmosphere.

  12. Precision expansion cloud chamber for homogeneous nucleation studies

    NASA Astrophysics Data System (ADS)

    Schmitt, John L.

    1981-11-01

    The author describes an expansion cloud chamber for the study of the nucleation of a single component vapor (homogeneous nucleation). The design draws on the many years of experience in this Center in construction of chambers for homogeneous nucleation of water. Design features of the chamber are: exact control of temperature (±0.03 ° C), pressure (±0.5 mm Hg), and automatic control of cycling. Construction features are: all construction materials are stainless steel, glass, or fluorocarbon plastics; the piston seal is a very flexible welded stainless steel bellows; the chamber can be made very clean by heating under vacuum and it is compatible with many substances, e.g., ethanol, nonane, and toluene. Performance features are: excellent repeatability of the expansion cycle over a temperature range of 45° to —15 °C and in day to day operation. Safety features are: automatic detection and warning and inerting against fire and explosion from combustible vapor in the chamber enclosure. The determination of the gas temperature at the maximum expansion is discussed as well as the importance of the ''fast'' pulse technique for the measurement of high nucleation rates.

  13. Measurement of methane emission from a landfill with flux chamber

    SciTech Connect

    Liao, W.P.; Chou, F.S.

    1998-12-31

    Two types of flux chamber have been employed to measure the emission rate of the greenhouse gases from a landfill. For realizing the dynamic fluid characteristics of the flux chamber, this study performed the airtight and tracer-retention-time tests in the lab, besides field experiment. The results of air-tightness test show that the chamber pressure varied with both fan speed and temperature. The fan speed at 200 rpm caused no significant pressure difference at constant room temperature. A burial depth between 3 and 6 cm will provide adequate air-tightness in the field. It is recommended that the effects of temperature, fan speed, and burial depth need to be studied before measuring. The retention time distribution (RTD) curves shows that the flux chamber designed for this research can be regarded as a completely mixing chamber. The tracer recovery rate was around 81--84% with carrier gas at 6 to 18 l/min and fan speed at 200 rpm. Preliminary results of the field measurement indicate that the emission rates of methane vary in location with four peaks on the side slopes. Most of the methane (87 percent) is emitting from the side slopes. The measured amount is much less than the theoretical estimate for this landfill.

  14. Design of an artificial lung compliance chamber for pulmonary replacement.

    PubMed

    Haft, Jonathan W; Bull, Joseph L; Rose, Rebecca; Katsra, Jeffrey; Grotberg, James B; Bartlett, Robert H; Hirschl, Ronald B

    2003-01-01

    Matching the impedance of an artificial lung for pulmonary replacement to native pulmonary impedance is important in preventing right ventricular dysfunction. A lumped-parameter theoretical model and bench-top experiments were used to investigate the effect of a prototype compliance chamber on input impedance. The bench-top simulation consisted of a pulsatile flow generator, a prototype compliance chamber, and a low resistance artificial lung connected in series. Effective compliance was varied using pneumatic compression. The theoretical model considered a similar circuit with resistors before and after a compliance element. The bundle flow pulsatility (flow amplitude divided by average flow) and input impedance were calculated in the theoretical and experimental models. More compliance and lower upstream resistance result in lower bundle flow pulsatility and reduced first harmonic impedance. Matching the time scale of the circuit to the period of pulsatile flow also reduces impedance. The bench-top circuit demonstrated an optimal chamber pressure at which first harmonic impedance is reduced by 80%. The prototype compliance chamber in series with the artificial lung more closely matches native pulmonary impedance. The lumped-parameter model and the bench-top simulation will aid in the design and testing of compliance chamber modifications to improve its efficiency.

  15. Method to calibrate fission chambers in Campbelling mode

    SciTech Connect

    Benoit Geslot; Troy C. Unruh; Philippe Filliatre; Christian Jammes; Jacques Di Salvo; Stéphane Bréaud; Jean-François Villard

    2011-06-01

    Fission chambers are neutron detectors which are widely used to instrument experimental reactors such as material testing reactors or zero power reactors. In the presence of a high level mixed gamma and neutron flux, fission chambers can be operated in Campbelling mode (also known as 'fluctuation mode' or 'mean square voltage mode') to provide reliable and precise neutron related measurements. Fission chamber calibration in Campbelling mode (in terms of neutron flux) is usually done empirically using a calibrated reference detector. A major drawback of this method is that calibration measurements have to be performed in a neutron environment very similar to the one in which the calibrated detector will be used afterwards. What we propose here is a different approach based on characterizing the fission chamber response in terms of fission rate. This way, the detector calibration coefficient is independent from the neutron spectrum and can be determined prior to the experiment. The fissile deposit response to the neutron spectrum can then be assessed independently by other means (experimental or numerical). In this paper, the response of CEA made miniature fission chambers in Campbelling mode is studied. We use a theoretical model of the signal to calculate the calibration coefficient. Input parameters of the model come from statistical distribution of individual pulses. Supporting measurements have been made in the CEA Cadarache zero power reactor MINERVE. Results are compared to an empirical Campbelling mode calibration.

  16. Experimental warming delays autumn senescence in a boreal spruce bog: Initial results from the SPRUCE experiment

    NASA Astrophysics Data System (ADS)

    Richardson, Andrew; Furze, Morgan; Aubrecht, Donald; Milliman, Thomas; Nettles, Robert; Krassovski, Misha; Hanson, Paul

    2016-04-01

    Phenology is considered one of the most robust indicators of the biological impacts of global change. In temperate and boreal regions, long-term data show that rising temperatures are advancing spring onset (e.g. budburst and flowering) and delaying autumn senescence (e.g. leaf coloration and leaf fall) in a wide range of ecosystems. While warm and cold temperatures, day length and insolation, precipitation and water availability, and other factors, have all been shown to influence plant phenology, the future response of phenology to rising temperatures and elevated CO2 still remains highly uncertain because of the challenges associated with conducting realistic manipulative experiments to simulate future environmental conditions. At the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) experiment in the north-central United States, experimental temperature (0 to +9° C above ambient) and CO2 (ambient and elevated) treatments are being applied to mature, and intact, Picea mariana-Sphagnum spp. bog communities in their native habitat through the use of ten large (approximately 12 m wide, 10 m high) open-topped enclosures. We are tracking vegetation green-up and senescence in these chambers, at both the individual and whole-community level, using repeat digital photography. Within each chamber, digital camera images are recorded every 30 minutes and uploaded to the PhenoCam (http://phenocam.sr.unh.edu) project web page, where they are displayed in near-real-time. Image processing is conducted nightly to extract quantitative measures of canopy color, which we characterize using Gcc, the green chromatic coordinate. Data from a camera mounted outside the chambers (since November 2014) indicate strong seasonal variation in Gcc for both evergreen shrubs and trees. Shrub Gcc rises steeply in May and June, and declines steeply in September and October. By comparison, tree Gcc rises gradually from March through June, and declines gradually from

  17. Chambers Air and Space Dictionary.

    NASA Astrophysics Data System (ADS)

    Walker, P. M. B.

    This dictionary is concerned with the sciences and technologies of everything above the Earth's surface. It has been developed from the database of Chambers Science and Technology Dictionary with many new and revised definitions in this group of fast-changing subjects. The book contains some 6000 definitions, including 1500 in aeronautics, 600 in astronomy, 500 in meteorology and 400 for space and radar. The special articles, placed in separate panels, are a major feature of the dictionary. These, many of which are illustrated, supply fuller treatments of major topics within each subject.

  18. Portable Ethylene Oxide Sterilization Chamber

    PubMed Central

    Songer, J. R.; Mathis, R. G.

    1969-01-01

    A portable ethylene oxide sterilization chamber was designed, constructed, and tested for use in the sterilization of embolectomy catheters. The unit can accommodate catheters up to 40 inches (101.6 cm) in length and can be operated for less than 4 cents per cycle. A constant concentration of 500 mg of ethylene oxide per liter of space and holding periods of 4 and 6 hr at 43 and 22 C, respectively, were adequate when tested with B. subtilis spores. The estimated cost of construction was $165.00. If temperature control is unnecessary, the cost is approximately $80.00. Images PMID:4977644

  19. Basic Aerodynamics of Combustion Chambers,

    DTIC Science & Technology

    1981-05-20

    8217, tie imnrulse foree eyuilibr-um c’ the bomd’~ leye - is 173 pv-:irJ p~76vJbK 2sO) IL !-. = Zn pT -- a , bV T. z -,,r y.re C era 3oia * ~~I" onc art-=e...heat by combustion all have very large influences on the capabilities of a combustion chamber. A yellow- colored flame represents diffusion combustion in...the wakes of fuel droplets. Blue- colored flames represent gaseous combustion of evaporated vapors which have already left the fuel droplets. The

  20. Main Chamber and Preburner Injector Technology

    NASA Technical Reports Server (NTRS)

    Santoro, Robert J.; Merkle, Charles L.

    1999-01-01

    This document reports the experimental and analytical research carried out at the Penn State Propulsion Engineering Research Center in support of NASA's plan to develop advanced technologies for future single stage to orbit (SSTO) propulsion systems. The focus of the work is on understanding specific technical issues related to bi-propellant and tri-propellant thrusters. The experiments concentrate on both cold flow demonstrations and hot-fire uni-element tests to demonstrate concepts that can be incorporated into hardware design and development. The analysis is CFD-based and is intended to support the design and interpretation of the experiments and to extrapolate findings to full-scale designs. The research is divided into five main categories that impact various SSTO development scenarios. The first category focuses on RP-1/gaseous hydrogen (GH2)/gaseous oxygen (GO2) tri-propellant combustion with specific emphasis on understanding the benefits of hydrogen addition to RP-1/oxygen combustion and in developing innovative injector technology. The second category investigates liquid oxygen (LOX)/GH2 combustion at main chamber near stoichiometric conditions to improve understanding of existing LOX/GH2 rocket systems. The third and fourth categories investigate the technical issues related with oxidizer-rich and fuel-rich propulsive concepts, issues that are necessary for developing the full-flow engine cycle. Here, injector technology issues for both LOX/GH2 and LOX/RP-1 propellants are examined. The last category, also related to the full-flow engine cycle, examines injector technology needs for GO2/GH2 propellant combustion at near-stoichiometric conditions for main chamber application.

  1. Crystalline heterogeneities and instabilities in thermally convecting magma chamber

    NASA Astrophysics Data System (ADS)

    Culha, C.; Suckale, J.; Qin, Z.

    2016-12-01

    A volcanic vent can supply different densities of crystals over an eruption time period. This has been seen in Hawai'i's Kilauea Iki 1959 eruption; however it is not common for all Kilauea or basaltic eruptions. We ask the question: Under what conditions can homogenous magma chamber cultivate crystalline heterogeneities? In some laboratory experiments and numerical simulations, a horizontal variation is observed. The region where crystals reside is identified as a retention zone: convection velocity balances settling velocity. Simulations and experiments that observe retention zones assume crystals do not alter the convection in the fluid. However, a comparison of experiments and simulations of convecting magma with crystals suggest that large crystal volume densities and crystal sizes alter fluid flow considerably. We introduce a computational method that fully resolves the crystalline phase. To simulate basaltic magma chambers in thermal convection, we built a numerical solver of the Navier-Stoke's equation, continuity equation, and energy equation. The modeled magma is assumed to be a viscous, incompressible fluid with a liquid and solid phase. Crystals are spherical, rigid bodies. We create Rayleigh-Taylor instability through a cool top layer and hot bottom layer and update magma density while keeping crystal temperature and size constant. Our method provides a detailed picture of magma chambers, which we compare to other models and experiments to identify when and how crystals alter magma chamber convection. Alterations include stratification, differential settling and instabilities. These characteristics are dependent on viscosity, convection vigor, crystal volume density and crystal characteristics. We reveal that a volumetric crystal density variation may occur over an eruption time period, if right conditions are met to form stratifications and instabilities in magma chambers. These conditions are realistic for Kilauea Iki's 1959 eruption.

  2. Chamber studies of atmospheric iodine chemistry

    NASA Astrophysics Data System (ADS)

    Buxmann, J.; Nájera, J.; Schmitt, S.; Bleicher, S.; Pöhler, D.; Horbanski, M.; Platt, U.; Zetzsch, C.; Bloss, W. J.

    2012-12-01

    Iodine chemistry has been shown to occur through much of the marine boundary layer (MBL). It leads to significant impacts upon atmospheric oxidising capacity, ozone levels and particle number concentration; however, there are major uncertainties in our knowledge of the iodine chemical reaction system, which limit our ability to accurately quantify these impacts using atmospheric models. In this work we report the results of novel atmospheric simulation chamber experiments, to study aspects of the fast gas-phase inorganic iodine oxide chemistry. We consider two specific issues here: First, in the presence of moderate levels of NO2, most current models predict that most active iodine should exist as INO3 (whose lifetime is controlled primarily by photolysis) and that levels of IO and OIO should be minimal. This is in contrast to observations from recent field measurements from semi-polluted coastal MBL locations which find significant levels of IO in the presence of NOx. Explanations include possible reactions of INO3 with I or O3 regenerating IO, or errors in the INO3 photochemical parameters. Second, while ozone loss is almost universally cited as a reason to study atmospheric iodine chemistry, calculations of the actual ozone destruction rate which results from a given iodine source term are rather uncertain - as we do not have quantitative understanding of the fate of the many potential iodine oxide species formed. This limits our ability to predict the steady state IO levels which will exist in equilibrium with a given iodine source term, and the resulting ozone loss rate. Recent field measurements in the MBL struggle to reconcile the observed IO with the measured iodine sources - indicating that additional sources exist, or alternatively that the model representation of the gas-phase iodine sink via higher iodine oxides is incorrect. We report the results from experiments performed in a 3.5 m3 indoor PTFE atmospheric simulation chamber located at Bay

  3. Thrust chamber material technology program

    NASA Astrophysics Data System (ADS)

    Andrus, J. S.; Bordeau, R. G.

    1989-03-01

    This report covers work performed at Pratt & Whitney on development of copper-based materials for long-life, reusable, regeneratively cooled rocket engine thrust chambers. The program approached the goal of enhanced cyclic life through the application of rapid solidification to alloy development, to introduce fine dispersions to strengthen and stabilize the alloys at elevated temperatures. After screening of alloy systems, copper-based alloys containing Cr, Co, Hf, Ag, Ti, and Zr were processed by rapid-solidification atomization in bulk quantities. Those bulk alloys showing the most promise were characterized by tensile testing, thermal conductivity testing, and elevated-temperature, low-cycle fatigue (LFC) testing. Characterization indicated that Cu- 1.1 percent Hf exhibited the greatest potential as an improved-life thrust chamber material, exhibiting LCF life about four times that of NASA-Z. Other alloys (Cu- 0.6 percent Zr, and Cu- 0.6 percent Zr- 1.0 percent Cr) exhibited promise for use in this application, but needed more development work to balance properties.

  4. Thrust chamber material technology program

    NASA Technical Reports Server (NTRS)

    Andrus, J. S.; Bordeau, R. G.

    1989-01-01

    This report covers work performed at Pratt & Whitney on development of copper-based materials for long-life, reusable, regeneratively cooled rocket engine thrust chambers. The program approached the goal of enhanced cyclic life through the application of rapid solidification to alloy development, to introduce fine dispersions to strengthen and stabilize the alloys at elevated temperatures. After screening of alloy systems, copper-based alloys containing Cr, Co, Hf, Ag, Ti, and Zr were processed by rapid-solidification atomization in bulk quantities. Those bulk alloys showing the most promise were characterized by tensile testing, thermal conductivity testing, and elevated-temperature, low-cycle fatigue (LFC) testing. Characterization indicated that Cu- 1.1 percent Hf exhibited the greatest potential as an improved-life thrust chamber material, exhibiting LCF life about four times that of NASA-Z. Other alloys (Cu- 0.6 percent Zr, and Cu- 0.6 percent Zr- 1.0 percent Cr) exhibited promise for use in this application, but needed more development work to balance properties.

  5. MPD thrust chamber flow dynamics

    NASA Astrophysics Data System (ADS)

    1990-08-01

    Flow within the thrust chamber of a Magnetoplasmadynamic (MPD) arcjet is examined experimentally and modeled with a 2-D magnetohydrodynamic code. Two quasi-steady MPD thrusters are considered under the same input conditions of current (21 kA) and total mass flow rate (0.006 kg/s, argon + 1.5 percent hydrogen). The arcjets have the same basic design, consisting of a central cathode, 3.8 cm diameter and 5 cm long, separated from a coaxial anode of equal length by a uniform gap of 2.3 cm. Two different mass injection arrangements are used (100 percent at mid-radius, and 50 percent at the cathode base, with the remainder at mid-radius). A new spectroscopic analysis procedure is developed that allows distributions of radial speed, heavy particle temperature and turbulent speed to be extracted from chordal measurements of light emission by the two species in the plasma flow. Good qualitative (and reasonable quantitative) agreement exists with distributions calculated by the MHD code, indicating that flow within the thrust chamber expands from an electromagnetically pumped plasma base (vs a pumped jet off the cathode tip). The significant variation of internal flow dynamics with mass injector arrangement implies the need for extensive experimentally validated code modeling in order to evaluate the potential performance of MPD thrusters.

  6. Tubular copper thrust chamber design study

    NASA Technical Reports Server (NTRS)

    Masters, A. I.; Galler, D. E.

    1992-01-01

    The use of copper tubular thrust chambers is particularly important in high performance expander cycle space engines. Tubular chambers have more surface area than flat wall chambers, and this extra surface area provides enhanced heat transfer for additional energy to power the cycle. This paper was divided into two sections: (1) a thermal analysis and sensitivity study; and (2) a preliminary design of a selected thrust chamber configuration. The thermal analysis consisted of a statistical optimization to determine the optimum tube geometry, tube booking, thrust chamber geometry, and cooling routing to achieve the maximum upper limit chamber pressure for a 25,000 pound thrust engine. The preliminary design effort produced a layout drawing of a tubular thrust chamber that is three inches shorter than the Advanced Expander Test Bed (AETB) milled channel chamber but is predicted to provide a five percent increase in heat transfer. Testing this chamber in the AETB would confirm the inherent advantages of tubular chamber construction and heat transfer.

  7. Rocket thrust chamber thermal barrier coatings

    NASA Technical Reports Server (NTRS)

    Quentmeyer, R. J.

    1985-01-01

    Subscale rocket thrust chamber tests were conducted to evaluate the effectiveness and durability of thin yttria stabilized zirconium oxide coatings applied to the thrust chamber hot-gas side wall. The fabrication consisted of arc plasma spraying the ceramic coating and bond coat onto a mandrell and then electrodepositing the copper thrust chamber wall around the coating. Chambers were fabricated with coatings .008, and .005 and .003 inches thick. The chambers were thermally cycled at a chamber pressure of 600 psia using oxygen-hydrogen as propellants and liquid hydrogen as the coolant. The thicker coatings tended to delaminate, early in the cyclic testing, down to a uniform sublayer which remained well adhered during the remaining cycles. Two chambers with .003 inch coatings were subjected to 1500 thermal cycles with no coating loss in the throat region, which represents a tenfold increase in life over identical chambers having no coatings. An analysis is presented which shows that the heat lost to the coolant due to the coating, in a rocket thrust chamber design having a coating only in the throat region, can be recovered by adding only one inch to the combustion chamber length.

  8. Development of a supercritical fluid extraction-gas chromatography-mass spectrometry method for the identification of highly polar compounds in secondary organic aerosols formed from biogenic hydrocarbons in smog chamber experiments.

    PubMed

    Chiappini, L; Perraudin, E; Durand-Jolibois, R; Doussin, J F

    2006-11-01

    A new one-step method for the analysis of highly polar components of secondary organic aerosols (SOA) has been developed. This method should lead to a better understanding of SOA formation and evolution since it enables the compounds responsible for SOA formation to be identified. Since it is based on supercritical fluid extraction coupled to gas chromatography-mass spectrometry, it minimizes the analysis time and significantly enhances sensitivity, which makes it suitable for trace-level compounds, which are constituents of SOA. One of the key features of this method is the in situ derivatisation step: an online silylation allowing the measurement of highly polar, polyfunctional compounds, which is a prerequisite for the elucidation of chemical mechanisms. This paper presents the development of this analytical method and highlights its ability to address this major atmospheric issue through the analysis of SOA formed from the ozonolysis of a biogenic hydrocarbon (sabinene). Ozonolysis of sabinene was performed in a 6 m3 Teflon chamber. The aerosol components were derivatised in situ. More than thirty products, such as sabinaketone, sabinic acid and other multifunctional compounds including dicarboxylic acids and oxoacids, were measured. Nine of them were identified and quantified. The sensitivity and the linearity (0.91

  9. Nonlinear structural analysis of cylindrical thrust chambers using viscoplastic models

    NASA Technical Reports Server (NTRS)

    Arya, Vinod K.

    1991-01-01

    The results are presented of a viscoplastic stress-strain analysis of a cylindrical thrust chamber used in experiments that were designed to simulate the SSME operating conditions. The inelastic strain was calculated by using a viscoplastic model, and a quasi-three-dimensional structural analysis was performed by using a finite element program MARC. The temperatures and pressures were calculated by using the loading cycles of experiments, and these temperatures and pressures were used in the computations. The deformed shape of the component was predicted after the end of each loading cycle. The predicted shape qualitatively replicated the deformed shape of the component as observed in experiments. The results indicate that the use of viscoplastic models for structural analysis may lead to more realistic life assessments of experimental thrust chambers.

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

    PubMed

    Yoshizumi, Maíra T; Caldas, Linda V E

    2012-07-01

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

  11. Subsoil Denitrification experiment at KBS MSU

    NASA Astrophysics Data System (ADS)

    Shcherbak, I.; Robertson, G. P.

    2010-12-01

    Denitrification plays two important roles in the global nitrogen cycle: returning active nitrogen to inert dinitrogen form and producing potent greenhouse gas nitrous oxide as a byproduct. Effects of denitrification in the deeper layers of soil on total soil denitrification are poorly understood. The experiment will be conducted at KBS to gain a better understanding dependency of rate of subsoil denitrification and molar ratio of denitrified N2O to N2 on depth in the profile and management practice applied. Experimental setup consists of 4 soil profiles (2 tilled and 2 no-till) enclosed in stainless steel boxes with open tops providing access to the soil profile for nondestructive measurements of soil temperature, soil moisture, soil atmosphere, and soil water (6 levels of measurements). Water discharged at the bottom of the profile (~2 m) is sampled as well as gas flux from the surface of the soil to the atmosphere. Inert tracer (hexafluoride) is introduced in the profile to estimate the diffusion rates. Profiles are planted to corn fertilized at 11.1 g/m2 with 50% 15N-Ammonium Nitrate to improve accuracy of measurement and calculate a complete nitrogen balance. Preliminary results show high concentrations of nitrous oxide in the subsoil layers (up to 6 ppm) which suggest high potential contribution of subsoil denitrification to total soil flux of nitrous oxide. Simplified setup consists of gas measurements at two depths in the soil profile (7 and 70 cm) and static chamber at the top. It will be installed in duplicates at conventional tillage, no-till, reduced input, organic, and early successional treatments of Long-Term Ecological Research Site at KBS to expand the scope of findings made with more complex system. Further validation and scaling of the results is possible in terms of integrated semi-empirical models. Predictive equations developed in the study will be used together with other parts of SALUS (System Approach to Land Use Sustainability) model. This

  12. KENNEDY SPACE CENTER, FLA. - Employees check out the new chamber facilities of the Space Life Sciences Lab (SLSL), formerly known as the Space Experiment Research and Processing Laboratory (SERPL). From left are Ray Wheeler, with NASA; Debbie Wells and Larry Burns, with Dynamac; A.O. Rule, president of Environmental Growth Chambers, Inc. (ECG); Neil Yorio, with Dynamac; and John Wiezchowski, with ECG. The SLSL is a state-of-the-art facility being built for ISS biotechnology research. Developed as a partnership between NASA-KSC and the State of Florida, NASA’s life sciences contractor will be the primary tenant of the facility, leasing space to conduct flight experiment processing and NASA-sponsored research. About 20 percent of the facility will be available for use by Florida’s university researchers through the Florida Space Research Institute.

    NASA Image and Video Library

    2003-09-10

    KENNEDY SPACE CENTER, FLA. - Employees check out the new chamber facilities of the Space Life Sciences Lab (SLSL), formerly known as the Space Experiment Research and Processing Laboratory (SERPL). From left are Ray Wheeler, with NASA; Debbie Wells and Larry Burns, with Dynamac; A.O. Rule, president of Environmental Growth Chambers, Inc. (ECG); Neil Yorio, with Dynamac; and John Wiezchowski, with ECG. The SLSL is a state-of-the-art facility being built for ISS biotechnology research. Developed as a partnership between NASA-KSC and the State of Florida, NASA’s life sciences contractor will be the primary tenant of the facility, leasing space to conduct flight experiment processing and NASA-sponsored research. About 20 percent of the facility will be available for use by Florida’s university researchers through the Florida Space Research Institute.

  13. Multilayer PDMS microfluidic chamber for controlling brain slice microenvironment.

    PubMed

    Blake, A J; Pearce, T M; Rao, N S; Johnson, S M; Williams, J C

    2007-07-01

    A novel three-layer microfluidic polydimethylsiloxane (PDMS) device was constructed with two fluid chambers that holds a brain slice in place with microposts while maintaining laminar perfusate flow above and below the slice. Our fabrication technique permits rapid production of PDMS layers that can be applied to brain slices of different shapes and sizes. In this study, the device was designed to fit the shape and thickness (530-700 microm) of a medullary brain slice taken from P0-P4 neonatal rats. Medullary slices in this chamber spontaneously produced rhythmic, respiratory-related motor output for up to 3 h, thereby demonstrating that brain slice viability was maintained for prolonged periods. This design is unique in that it achieves independent control of fluids through multiple channels in two separate fluid chambers. The laminar flow exhibited by the microfluidic chamber allows controlled solutions to target specific areas of the brain slice based on the input flow rates. To demonstrate this capability, a stream of Na(+)-free solution was focused on one half of a medullary slice to abolish spontaneous neural activity in only that half of the brain slice, while the other half remained active. We also demonstrated that flow of different solutions can be focused over the midline of the brain slice. The multilayer brain slice chamber design can integrate several traditional types of electrophysiology tools that are commonly used to measure neurophysiological properties of brain slices. Thus, this new microfluidic chamber is advantageous for experiments that involve controlled drug or solution delivery at high spatiotemporal resolution.

  14. Multilayer PDMS microfluidic chamber for controlling brain slice microenvironment

    PubMed Central

    Blake, A. J.; Pearce, T. M.; Rao, N. S.; Johnson, S. M.; Williams, J. C.

    2008-01-01

    A novel three-layer microfluidic polydimethylsiloxane (PDMS) device was constructed with two fluid chambers that holds a brain slice in place with microposts while maintaining laminar perfusate flow above and below the slice. Our fabrication technique permits rapid production of PDMS layers that can be applied to brain slices of different shapes and sizes. In this study, the device was designed to fit the shape and thickness (530-700 μm) of a medullary brain slice taken from P0-P4 neonatal rats. Medullary slices in this chamber spontaneously produced rhythmic, respiratory-related motor output for up to 3 h, thereby demonstrating that brain slice viability was maintained for prolonged periods. This design is unique in that it achieves independent control of fluids through multiple channels in two separate fluid chambers. The laminar flow exhibited by the microfluidic chamber allows controlled solutions to target specific areas of the brain slice based on the input flow rates. To demonstrate this capability, a stream of Na+-free solution was focused on one half of a medullary slice to abolish spontaneous neural activity in only that half of the brain slice, while the other half remained active. We also demonstrated that flow of different solutions can be focused over the midline of the brain slice. The multilayer brain slice chamber design can integrate several traditional types of electrophysiology tools that are commonly used to measure neurophysiological properties of brain slices. Thus, this new microfluidic chamber is advantageous for experiments that involve controlled drug or solution delivery at high spatiotemporal resolution. PMID:17594002

  15. Neutron-chamber detectors and applications

    SciTech Connect

    Fehlau, P.E.; Atwater, H.F.; Coop, K.L.

    1990-01-01

    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.

  16. Chamber leakage effects on measured gas concentrations during contained demilitarization tests at NTS X-Tunnel

    SciTech Connect

    Christopher R. Shadix; Joel Lipkin

    1999-11-01

    A series of contained explosive detonation and propellant burn experiments was conducted during 1996 and 1997 using a specially constructed, large, underground chamber located in the X-tunnel complex at Area 25 of the Nevada Test Site (NTS).

  17. The ARGUS microvertex drift chamber

    NASA Astrophysics Data System (ADS)

    Michel, E.; Schmidt-Parzefall, W.; Appuhn, R. D.; Buchmüller, J.; Kolanoski, H.; Kreimeier, B.; Lange, A.; Siegmund, T.; Walther, A.; Edwards, K. W.; Fernholz, R. C.; Kapitza, H.; MacFarlane, D. B.; O'Neill, M.; Parsons, J. A.; Prentice, J. D.; Seidel, S. C.; Tsipolitis, G.; Ball, S.; Babaev, A.; Danilov, M.; Tichomirov, I.

    1989-11-01

    The ARGUS collaboration is currently building a new microvertex drift chamber (μVDC) as an upgrade of their detector. The μVDC is optimized for B-meson physics at DORIS energies. Important design features are minimal multiple scattering for low-momentum particles and three-dimensional reconstruction of decay vertices with equal resolutions in r- φ and r- z. Vertex resolutions of 15-25 μm are expected. Prototypes of the μVDC have been tested with different gas mixtures at various pressures. Spatial resolutions as small as 20 μm were obtained using CO 2/propane at 4 bar and DME at 1 bar. New readout electronics have been developed for the μVDC aiming at low thresholds for the TDC measurements. Employing a novel idea for noise and cross-talk suppression, which is based on a discrimination against short pulses, very low threshold settings are possible.

  18. An airborne isothermal haze chamber

    NASA Technical Reports Server (NTRS)

    Hindman, E. E.

    1981-01-01

    Thermal gradient diffusion cloud chambers (TGDCC) are used to determine the concentrations of cloud condensation nuclei (CCN) with critical supersaturations greater than or equal to about 0.2%. The CCN concentrations measured with the airborne IHC were lower than theoretically predicted by factors ranging between 7.9 and 9.0. The CCN concentrations measured with the airborne IHC were lower than the concentrations measured with the larger laboratory IHC's by factors ranging between 3.9 and 7.5. The bounds of the supersaturation ranges of the airborne IHC and the CSU-Mee TGDCC do not overlap. Nevertheless, the slopes of the interpolated data between the bounds agree favorably with the theoretical slopes.

  19. Variable oven chamber heating level

    SciTech Connect

    Minasov, A.M.; Sergeev, S.S.; Likhogyb, E.P.

    1984-01-01

    Changes in oven chambers were developed to prevent the uneven heating of a charge in a coke oven. The changes basically altered the heat flow to a charge into the upper section upon a variation in the shrinkage properties of a charge. The engineering modifications are described and illustrated. A damper placed in a converted door is sufficiently easily shifted in the vertical plane and is firmly fixed in the upper position. The distribution of temperatures in the upper part of coke cake is changed within the limits of 80/sup 0/C, depending on the location of the damper in the converted door. When the damper is in the lower position, heating of the upper part of the coke cake increases, and the difference in the temperatures of the coke relative to height is decreased, and vice versa.

  20. IFE Chamber Technology - Status and Future Challenges

    SciTech Connect

    Meier, W.R.; Raffray, A.R.; Abdel-Khalik, S.I.; Kulcinski, G.L.; Latowski, J.F.; Najmabadi, F.; Olson, C.L.; Peterson, P.F.; Ying, A.; Yoda, M.

    2003-07-15

    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. Fluidized wall for protecting fusion chamber walls

    DOEpatents

    Maniscalco, James A.; Meier, Wayne R.

    1982-01-01

    Apparatus for protecting the inner wall of a fusion chamber from microexplosion debris, x-rays, neutrons, etc. produced by deuterium-tritium (DT) targets imploded within the fusion chamber. The apparatus utilizes a fluidized wall similar to a waterfall comprising liquid lithium or solid pellets of lithium-ceramic, the waterfall forming a blanket to prevent damage of the structural materials of the chamber.

  2. Free-Flow Open-Chamber Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Free-flow open-chamber electrophoresis variant of free-flow electrophoresis performed in chamber with open ends and in which velocity of electro-osmotic flow adjusted equal to and opposite mean electrophoretic velocity of sample. Particles having electrophoretic mobilities greater than mean mobility of sample particles move toward cathode, those with mobilities less move toward anode. Technique applied to separation of components of mixtures of biologically important substances. Sensitivity enhanced by use of tapered chamber.

  3. Drift chamber tracking with neural networks

    SciTech Connect

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

    1992-10-01

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

  4. IFE Chamber Technology - Status and Future Challenges

    SciTech Connect

    Meier, W R; Raffrary, A R; Abdel-Khalik, S; Kulcinski, G; Latkowski, J F; Najmabadi, F; Olson, C L; Peterson, P F; Ying, A; Yoda, M

    2002-11-15

    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 dry-wall (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.

  5. D0 central tracking chamber performance studies

    SciTech Connect

    Pizzuto, Domenico

    1991-12-01

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

  6. Engineering verification of the biomass production chamber

    NASA Technical Reports Server (NTRS)

    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.

  7. Thrust chamber thermal barrier coating techniques

    NASA Technical Reports Server (NTRS)

    Quentmeyer, Richard J.

    1988-01-01

    Methods for applying thermal barrier coatings to the hot-gas side wall of rocket thrust chambers in order to significantly reduce the heat transfer in high heat flux regions was the focus of technology efforts for many years. This paper describes a successful technique developed by the Lewis Research Center that starts with the coating of a mandrel and then builds the thrust chamber around it by electroforming appropriate materials. This results in a smooth coating with exceptional adherence, demonstrated in hot fire rig tests. The low cycle fatigue life of chambers with coatings applied in this manner was increased dramatically compared to uncoated chambers.

  8. Thrust chamber thermal barrier coating techniques

    NASA Technical Reports Server (NTRS)

    Quentmeyer, Richard J.

    1989-01-01

    Methods for applying thermal barrier coatings to the hot-gas side wall of rocket thrust chambers in order to significantly reduce the heat transfer in high heat flux regions has been the focus of technology efforts for many years. A successful technique developed by NASA-Lewis that starts with the coating on a mandrel and then builds the thrust chamber around it by electroforming appropriate materials is described. This results in a smooth coating with exceptional adherence, as was demonstrated in hot fire rig tests. The low cycle fatigue life of chambers with coatings applied in this manner was increased dramatically compared to uncoated chambers.

  9. The Mark II Vertex Drift Chamber

    SciTech Connect

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

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 2} gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.

  10. Investigation of background radical sources in a teflon-film irradiation chamber

    SciTech Connect

    Glasson, W.A.; Dunker, A.M. )

    1988-09-01

    In attempts to model hydrocarbon/NOx irradiations carried out in smog chambers, workers have found it necessary to postulate background free radical sources. Without such radical sources, it has not been possible to obtain agreement between the predictions of chemical mechanisms and the chamber data. The background radical sources appear to be specific to chambers and are not used when applying chemical mechanisms to simulate the atmosphere. Until recently, there were no experimental measurements of the radical sources, and as a result assumptions on the nature and magnitude of the sources varied. Differences in these assumptions are responsible for some of the differences in the predictions of chemical mechanisms in atmospheric simulations. Experimental determinations of the background radical sources in different chambers are, therefore, imperative for the effective use of chamber experiments in developing and evaluating chemical mechanisms for smog formation. In this work, they have conducted a detailed study of the background radical sources in a small Teflon-film chamber. The purpose was to determine the usefulness of such chambers for quantitative studies of smog formation. Values for the background radical sources were derived from the experimental data by simulations with a detailed chemical mechanism, and the uncertainties in these values were estimated as well. The effects of various parameters, such as light intensity and NO and NO{sub 2} concentrations, on the radical sources were studied to provide the necessary information for taking these sources into account in modeling future chamber experiments.

  11. Evaluation of oxide-coated iridium-rhenium chambers

    NASA Technical Reports Server (NTRS)

    Reed, Brian D.

    1994-01-01

    Iridium-coated rhenium (Ir-Re) provides long life operation of radiation-cooled rockets at temperatures up to 2200 C. Ceramic oxide coatings could be used to increase Ir-Re rocket lifetimes and allow operation in highly oxidizing environments. Ceramic oxide coatings promise to serve as both thermal and diffusion barriers for the iridium layer. Seven ceramic oxide-coated Ir-Re, 22-N rocket chambers were tested with gaseous hydrogen/gaseous oxygen (GHz/G02) propellants. Five chambers had thick (over 10 mils), monolithic coatings of either hafnia (HfO2) or zirconia (ZrO2). Two chambers had coatings with thicknesses less than 5 mils. One of these chambers had a thin-walled coating of ZrO2 infiltrated with sol gel HfO2. The other chamber had a coating composed of an Ir-oxide composite. The purpose of this test program was to assess the ability of the oxide coatings to withstand the thermal shock of combustion initiation, adhere under repeated thermal cycling, and operate in aggressively oxidizing environments. All of the coatings survived the thermal shock of combustion and demonstrated operation at mixture ratios up to 11. Testing the Ir-oxide composite-coated chamber included over 29 min at mixture ratio 16. The thicker walled coatings provided the larger temperature drops across the oxide layer (up to 570 C), but were susceptible to macrocracking and eventual chipping at a stress concentrator. The cracks apparently resealed during firing, under compression of the oxide layer. The thinner walled coatings did not experience the macrocracking and chipping of the chambers that was seen with the thick, monolithic coatings. However, burn-throughs in the throat region did occur in both of the thin-walled chambers at mixture ratios well above stoichiometric. The burn-throughs were probably the result of oxygen diffusion through the oxide coating that allowed the underlying Ir and Re layers to be oxidized. The results of this test program indicated that the thin-walled oxide

  12. Chamber and target technology development for inertial fusion energy

    SciTech Connect

    Abdou, M; Besenbruch, G; Duke, J; Forman, L; Goodin, D; Gulec, K; Hoffer, J; Khater, H; Kulcinsky, G; Latkowski, J F; Logan, B G; Margevicious, B; Meier, W R; Moir, R W; Morley, N; Nobile, A; Payne, S; Peterson, P F; Peterson, R; Petzoldt, R; Schultz, K; Steckle, W; Sviatoslavsky, L; Tillack, M; Ying, A

    1999-04-07

    Fusion chambers and high pulse-rate target systems for inertial fusion energy (IFE) must: regenerate chamber conditions suitable for target injection, laser propagation, and ignition at rates of 5 to 10 Hz; extract fusion energy at temperatures high enough for efficient conversion to electricity; breed tritium and fuel targets with minimum tritium inventory; manufacture targets at low cost; inject those targets with sufficient accuracy for high energy gain; assure adequate lifetime of the chamber and beam interface (final optics); minimize radioactive waste levels and annual volumes; and minimize radiation releases under normal operating and accident conditions. The primary goal of the US IFE program over the next four years (Phase I) is to develop the basis for a Proof-of-Performance-level driver and target chamber called the Integrated Research Experiment (IRE). The IRE will explore beam transport and focusing through prototypical chamber environment and will intercept surrogate targets at high pulse rep-rate. The IRE will not have enough driver energy to ignite targets, and it will be a non-nuclear facility. IRE options are being developed for both heavy ion and laser driven IFE. Fig. 1 shows that Phase I is prerequisite to an IRE, and the IRE plus NIF (Phase II) is prerequisite to a high-pulse rate. Engineering Test Facility and DEMO for IFE, leading to an attractive fusion power plant. This report deals with the Phase-I R&D needs for the chamber, driver/chamber interface (i.e., magnets for accelerators and optics for lasers), target fabrication, and target injection; it is meant to be part of a more comprehensive IFE development plan which will include driver technology and target design R&D. Because of limited R&D funds, especially in Phase I, it is not possible to address the critical issues for all possible chamber and target technology options for heavy ion or laser fusion. On the other hand, there is risk in addressing only one approach to each technology

  13. A recording chamber for small volume slice electrophysiology.

    PubMed

    Dondzillo, Anna; Quinn, Kevin D; Cruickshank-Quinn, Charmion I; Reisdorph, Nichole; Lei, Tim C; Klug, Achim

    2015-09-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products. Copyright © 2015 the American Physiological Society.

  14. Resistive Plate Chamber Efficiency & Rate Capability Analysis

    NASA Astrophysics Data System (ADS)

    Candocia, Max

    2012-10-01

    Bakelite-based resistive plate chambers (RPCs) are particle detectors commonly used in muon trigger systems for high-energy physics experiments. Bakelite RPCs combine fast response, sufficient position resolution and low cost, and they can be operated at instantaneous background rates up to approximately 1.5 kHz/cm^2. Current and future collider experiments will demand operation of trigger RPCs under background rates higher than what is currently achieved. The rate capability is related to the bulk and surface conductivities of the Bakelite material used for the plates bordering the active gas volume in the RPCs. At the LHC and RHIC, these surfaces are coated with linseed oil, which lowers the surface resistivity of the Bakelite, which, to a point, improves the rate capability of the detectors. We have doped our own plates with various concentrations of carbon black. Over the past year we have tested RPCs with Bakelite plates of different resistivity using cosmic ray muons and radioactive Fe55 sources to emulate different levels of background in the detector. Results on the RPC efficiencies at different background rates and for different Bakelite coatings will be presented.

  15. Spin-dependent WIMP limits from a bubble chamber.

    PubMed

    Behnke, E; Collar, J I; 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

    2008-02-15

    Bubble chambers were the dominant technology used for particle detection in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on a new application for these devices. We operated an ultraclean, room-temperature bubble chamber containing 1.5 kilograms of superheated CF3I, a target maximally sensitive to spin-dependent and -independent weakly interacting massive particle (WIMP) couplings. An extreme intrinsic insensitivity to the backgrounds that commonly limit direct searches for dark matter was measured in this device under operating conditions leading to the detection of low-energy nuclear recoils like those expected from WIMPs. Improved limits on the spin-dependent WIMP-proton scattering cross section were extracted during our experiments, excluding this type of coupling as a possible explanation for a recent claim of particle dark-matter detection.

  16. Nonlinear saturation of thermoacoustic oscillations in annular combustion chambers

    NASA Astrophysics Data System (ADS)

    Ghirardo, Giulio; Juniper, Matthew

    2014-11-01

    Continuous combustion systems such as aeroplane engines can experience self-sustained pressure oscillations, called thermoacoustic oscillations. Quite often the combustion chamber is rotationally symmetric and confined between inner and outer walls, with a fixed number of burners equispaced along the annulus, at the chamber inlet. We focus on thermoacoustic oscillations in the azimuthal direction, and discuss the nonlinear saturation of the system towards 2 types of solutions: standing waves (with velocity and pressure nodes fixed in time and in space) and spinning waves (rotating waves, in clockwise or anti-clockwise direction). We neglect the effect of the transverse velocity oscillating in the azimuthal direction in the combustion chamber, and focus the model on the nonlinear effect that the longitudinal velocity, just upstream of each burner, has on the fluctuating heat-release response in the chamber. We present a low-order analytical framework to discuss the stability of the 2 types of solutions. We discuss how the stability and amplitudes of the 2 solutions depend on: 1) the acoustic damping in the system; 2) the number of injectors equispaced in the annulus; 3) the nonlinear response of the flames.

  17. Raymond J. Chambers--A Personal Reflection

    ERIC Educational Resources Information Center

    Gaffikin, Michael

    2012-01-01

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

  18. Incinerator system arrangement with dual scrubbing chambers

    SciTech Connect

    Domnitch, I.

    1987-01-13

    An incinerator arrangement is described comprising: an incinerator housing located near the lowest point in a building, the housing containing incinerator elements therein; a chute-flue having a first end in communication with the incinerator housing, a second end at the top of the building for evacuation of combustion gases to the atmosphere therethrough, and at least one intermediately located waste disposal opening through which waste is dropped into the incinerator housing; the incinerator elements including: a main combustion chamber, an opening between the main combustion chamber and the first end of the chute-flue and a flue-damper covering the opening. The flue-damper is biased in a closed position and being operable by the weight of waste to admit the waste into the combustion chamber; a scrubbing chamber located exteriorly along the top of the combustion chamber and having a first opening into the combustion chamber and a second opening into the chute-flue; and water spraying means in the scrubbing chamber for directing a water spray at the combustion gases to wash particulate matter from the gases before the gases enter the chute-flue whereby the water spraying means which are located adjacent the combustion chamber are protected against freezing and the elements.

  19. Studying Phototropism Using a Small Growth Chamber.

    ERIC Educational Resources Information Center

    Fisher, Maryanna, F.; Llewellyn, Gerald C.

    1978-01-01

    Describes a simple and inexpensive way to construct two small growth chambers for studying phototropism in the science classroom. One chamber is designed to illustrate how plants grow around obstacles to reach light and the other to illustrate directional light responses. (HM)

  20. Space Power Facility Reverberation Chamber Calibration Report

    NASA Technical Reports Server (NTRS)

    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.

  1. Raymond J. Chambers--A Personal Reflection

    ERIC Educational Resources Information Center

    Gaffikin, Michael

    2012-01-01

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

  2. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a...

  3. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a...

  4. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a...

  5. Promoting "Minds-on" Chamber Music Rehearsals

    ERIC Educational Resources Information Center

    Berg, Margaret H.

    2008-01-01

    Chamber music provides myriad opportunities to develop students' ability to think like professional musicians while engaged in the authentic task of working closely with and learning from peers. However, the potential for musical growth inherent in chamber music participation is often unrealized due to either a lack of teacher guidance and support…

  6. 21 CFR 868.5470 - Hyperbaric chamber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... hyperbaric chamber is a device that is intended to increase the environmental oxygen pressure to promote the movement of oxygen from the environment to a patient's tissue by means of pressurization that is greater than atmospheric pressure. This device does not include topical oxygen chambers for extremities (§...

  7. 21 CFR 868.5470 - Hyperbaric chamber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... hyperbaric chamber is a device that is intended to increase the environmental oxygen pressure to promote the movement of oxygen from the environment to a patient's tissue by means of pressurization that is greater than atmospheric pressure. This device does not include topical oxygen chambers for extremities (§...

  8. 21 CFR 868.5470 - Hyperbaric chamber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... hyperbaric chamber is a device that is intended to increase the environmental oxygen pressure to promote the movement of oxygen from the environment to a patient's tissue by means of pressurization that is greater than atmospheric pressure. This device does not include topical oxygen chambers for extremities (§...

  9. 21 CFR 868.5470 - Hyperbaric chamber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... hyperbaric chamber is a device that is intended to increase the environmental oxygen pressure to promote the movement of oxygen from the environment to a patient's tissue by means of pressurization that is greater than atmospheric pressure. This device does not include topical oxygen chambers for extremities (§...

  10. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a...

  11. 21 CFR 866.2120 - Anaerobic chamber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Anaerobic chamber. 866.2120 Section 866.2120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a...

  12. Compact ion chamber based neutron detector

    DOEpatents

    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.

  13. Anechoic chamber qualification at ultrasonic frequencies

    NASA Astrophysics Data System (ADS)

    Jenny, Trevor; Anderson, Brian

    2010-10-01

    Qualifying an anechoic chamber for frequencies that extend into the ultrasonic range is necessary for research work involving airborne ultrasonic sound. For example, an anechoic chamber allows for measurements of the direct sound radiated by an object without reflections from walls. The ANSI S12.55/ISO 3745 standard which covers anechoic chamber qualification does not extend into the ultrasonic frequency range, nor have others discussed this frequency range in the literature. An increasing number of technologies are employing ultrasound; hence the need to develop facilities to conduct basic research studies on airborne ultrasound. This presentation will discuss the challenges associated with chamber qualification and present the results for qualification of a chamber at Brigham Young University. [This work has been funded by the Los Alamos National Laboratory

  14. Ionization-chamber smoke detector system

    DOEpatents

    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.

  15. Advanced tube-bundle rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Kazaroff, John M.; Pavli, Albert J.

    1990-01-01

    An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

  16. An atmospheric exposure chamber for small animals

    NASA Technical Reports Server (NTRS)

    Glaser, R. M.; Weiss, H. S.; Pitt, J. F.; Grimard, M.

    1982-01-01

    The purpose of this project was to design a long-term environmental exposure chamber for small animals. This chamber is capable of producing hypoxic, normoxic and hyperoxic atmospheres which are closely regulated. The chamber, which is of the recycling type, is fashioned after clear plastic germ-free isolators. Oxygen concentration is set and controlled by a paramagnetic O2 analyzer and a 3-way solenoid valve. In this way either O2 or N2 may be provided to the system by way of negative O2 feedback. Relative humidity is maintained at 40-50 percent by a refrigeration type dryer. Carbon dioxide is absorbed by indicating soda lime. A diaphragm pump continuously circulates chamber gas at a high enough flow rate to prevent buildup of CO2 and humidity. This chamber has been used for numerous studies which involve prolonged exposure of small animals to various O2 concentrations.

  17. Advanced tube-bundle rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Kazaroff, John M.; Pavli, Albert J.

    1990-01-01

    An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

  18. An atmospheric exposure chamber for small animals

    NASA Technical Reports Server (NTRS)

    Glaser, R. M.; Weiss, H. S.; Pitt, J. F.; Grimard, M.

    1982-01-01

    The purpose of this project was to design a long-term environmental exposure chamber for small animals. This chamber is capable of producing hypoxic, normoxic and hyperoxic atmospheres which are closely regulated. The chamber, which is of the recycling type, is fashioned after clear plastic germ-free isolators. Oxygen concentration is set and controlled by a paramagnetic O2 analyzer and a 3-way solenoid valve. In this way either O2 or N2 may be provided to the system by way of negative O2 feedback. Relative humidity is maintained at 40-50 percent by a refrigeration type dryer. Carbon dioxide is absorbed by indicating soda lime. A diaphragm pump continuously circulates chamber gas at a high enough flow rate to prevent buildup of CO2 and humidity. This chamber has been used for numerous studies which involve prolonged exposure of small animals to various O2 concentrations.

  19. Signal propagation in long wire chambers

    NASA Astrophysics Data System (ADS)

    Bock, P.; Engelfried, J.; Friedrich, T.; Heintze, J.; Lennert, P.; Russ, M.; Zimmer, M.

    2012-09-01

    The propagation of signals in long proportional counters or multi-wire tracking chambers is simulated, using numerical solutions of the multi-wire telegraph equations. The results are compared to experimental data, recorded with a proportional counter and a multi-wire test chamber. The signal shape, the charge division ratio and, in the case of the drift chamber, also the cross talk between the wires, are well reproduced. Similar shapes for signals and their cross talk can be obtained with a properly chosen electrical termination. It is shown how data from a multi-wire chamber can then be corrected for cross talk. The effects limiting the precision of position measurements along the wires with the charge division method are discussed. The simulation was applied to the reconstruction of tracks measured with the OPAL JET chamber.

  20. The response of a scintillation counter below an emulsion chamber to heavy nucleus interactions in the chamber

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Dake, S.; Derrickson, J. H.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Hayashi, T.; Holynski, R.; Iwai, J.; hide

    1985-01-01

    In 1982 a hybrid electronic counter-emulsion chamber experiment was flown on a balloon to study heavy nucleus interactions in the 20 to approximately 100 GeV/AMU energy range. A gas Cerenkov counter, two solid Cerenkov counters, and a proportional counter hodoscope gave the primary energy, the primary charge and the trajectory of the particles, respectively. Using the trajectory information cosmic ray nuclei of Z 10 were found reliably and efficiently, and interaction characteristics of the Fe group nuclei were measured in the chamber. A plastic scintillator below the emulsion chamber responded to showers resulting from interactions in the chamber and to noninteracting nuclei. Data on the response of the counter have been compared with simulations of hadronic-electromagnetic cascades to derive the average neutral energy fraction released by the heavy interactions, and to predict the performance of this kind of counter at higher energies. For the interacting events of highest produced particles multiplicity comparison between various simulations and the shower counter signal have been made.