Effects of Isoprene- and Toluene-Generated Smog on Allergic ...

EPA Pesticide Factsheets

Reactions of organic compounds with nitric oxide (NO) and sunlight produce complex mixtures of pollutants including secondary organic aerosol (SOA), ozone (O3), nitrogen dioxide (NO2), and reactive aldehydes. The health effects of these photochemical smog mixtures in susceptible populations including asthmatics are unclear. We assessed effects of smog generated from mixtures of NO with isoprene (IS) or toluene (TL) on allergic inflammatory responses in Balb/cJ mice. House dust mite (HDM)-sensitized or control mice were all challenged with HDM intranasally 1 d prior to whole-body inhalation exposure to IS (chamber average 509 ppb NO2, 246 ppb O3, and 160 g/m3 SOA), TL (217 ppb NO2, 129 ppb O3, and 376 g/m3 SOA), or HEPA-filtered air (4 h/d for 2 days). Mice were necropsied within 3 h after the second exposure (2 d post-HDM challenge). Assessment of breathing parameters during exposure with double-chamber plethysmography showed a trend for increased specific airway resistance and decreased minute volume during the second day of TL exposure in both non-allergic and HDM-allergic mice. HDM-allergic air-exposed mice had significant increases in numbers of bronchoalveolar lavage (BAL) alveolar macrophages (AM) and eosinophils (EO), and trends for increases in BAL indices of lung injury in comparison with non-allergic air-exposed mice. Exposure to either IS or TL attenuated the increases in AM, EO, and lung injury markers in HDM-allergic mice. The results of this

Response of ozone to changes in hydrocarbon and nitrogen oxide concentrations in outdoor smog chambers filled with Los Angeles air

NASA Astrophysics Data System (ADS)

Kelly, Nelson A.; Gunst, Richard F.

During the summer portion of the 1987 Southern California Air Quality Study (SCAQS), outdoor smog chamber experiments were performed on Los Angeles air to determine the response of maximum ozone levels, O 3(max), to changes in the initial concentrations of hydrocarbons, HC, and nitrogen oxides, NO x. These captive-air experiments were conducted in downtown Los Angeles and in the downwind suburb of Claremont. Typically, eight chambers were filled with LA air in the morning. In some chambers the initial HC and/or NO x concentrations were changed by 25% to 50% by adding various combinations of a mixture of HC, clean air, or NO x. The O 3 concentration in each chamber was monitored throughout the day to determine O 3(max). An empirical mathematical model for O 3(max) was developed from regression fits to the initial HC and NO x concentrations and to the average daily temperature at both sites. This is the first time that a mathematical expression for the O 3-precursor relationship and the positive effect of temperature on O 3(max) have been quantified using captive-air experiments. An ozone isopleth diagram prepared from the empirical model was qualitatively similar to those prepared from photochemical mechanisms. This constitutes the first solely empirical corroboration of the O 3 contour shape for Los Angeles. To comply with the Federal Ozone Standard in LA, O 3(max) must be reduced by approximately 50%. Several strategies for reducing O 3(max) by 50% were evaluated using the empirical model. For the average initial conditions that we measured in LA, the most efficient strategy is one that reduces HC by 55-75%, depending on the ambient HC/NO x ratio. Any accompanying reduction in NO x would be counter-productive to the benefits of HC reductions. In fact, reducing HC and NO x simultaneously requires larger percentage reductions for both than the reduction required when HC alone is reduced. The HC-reduction strategy is the most efficient on average, but no single

The effects of atmospheric processes on tehran smog forming.

PubMed

Mohammadi, H; Cohen, D; Babazadeh, M; Rokni, L

2012-01-01

Air pollution is one of the most important problems in urban areas that always threaten citizen's health. Photochemical smog is one of the main factors of air pollution in large cities like Tehran. Usually smog is not only a part of nature, but is being analyzed as an independent matter, which highly affects on the nature. It has been used as relationship between atmospheric elements such as temperature, pressure, relative humidity, wind speed with inversion in the time of smog forming and weather map in 500 Hpa level during 9 years descriptive static by using correlation coefficient in this analyze. Results show that there is a meaningful correlation between atmospheric elements and smog forming. This relation is seen between monthly average of these elements and monthly average of smog forming. However, when temperature decreases, corresponding pressure will increase and result of this will be smog forming. Usually smog increases in cold months of year due to enter cold high pressure air masses in Iran during December and January that is simultaneous with decreasing temperature and air pressure increases and inversion height distance decreases from the earth surface which cause to integrate air pollution under its surface, will cause to form smog in Tehran. It shows a meaningful and strong relation, based on resultant relations by correlation coefficient from inversion height and smog forming, so that obtained figure is more than 60% .

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

A smog chamber comparison of a microfluidic derivatisation measurement of gas-phase glyoxal and methylglyoxal with other analytical techniques

NASA Astrophysics Data System (ADS)

Pang, xiaobing; Lewis, Alastair; Rickard, Andrew R.; Baeza-Romero, Maria Teresa; Adams, Thomas J.; Ball, Stephen M.; Goodall, Iain C. A.; Monks, Paul S.; Peppe, Salvatore; Ródenas García, Milagros; Sánchez, Pilar; Muñoz, Amalia

2014-05-01

A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation reagent and a microfabricated planar glass micro-reactor comprising an inlet, gas and fluid splitting and combining channels, mixing junctions, and a heated capillary reaction microchannel. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the micro-reactor result in a fast and highly efficient derivatisation reaction, generating an effluent stream ready for direct introduction to a gas chromatograph-mass spectrometer (GC-MS). A linear response for GLY was observed over a calibration range 0.7 to 400 ppbV, and for MGLY of 1.2 to 300 ppbV, when derivatised under optimal reaction conditions. The analytical performance shows good accuracy (6.6 % for GLY and 7.5 % for MGLY), suitable precision (< 12.0 %) and method detection limits (MDLs) (75 pptV for GLY and 185 pptV for MGLY) with a time resolution of 30 minutes. These MDLs are below or close to typical concentrations of these compounds observed in ambient air. The microfluidic derivatisation technique would be appropriate for ambient α-dicarbonyl measurements in a range of field environments based on its performance in a large-scale outdoor atmospheric simulation chamber (EUPHORE). The feasibility of the technique was assessed by applying the methodology to quantify of α-dicarbonyls formed during the photo-oxidation of isoprene in the EUPHORE chamber. Good correlations were found between microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR) with the correlation coefficient (r2) of 0.84, Broad Band Cavity Enhanced Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro extraction (SPME) (r2 = 0.89), and a

Interpretation of Secondary Organic Aerosol Formation from Diesel Exhaust Photooxidation in an Environmental Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakao, Shunsuke; Shrivastava, ManishKumar B.; Nguyen, Anh

2011-04-14

Secondary organic aerosol (SOA) formation from diesel exhaust in a smog chamber was investigated. Particle volume measurement based on mobility diameter is shown to underestimate SOA formation from diesel exhaust due to the external void space of agglomerate particles, in which case mass-based measurement technique is necessary. Rapid determination of particle effective density as a function of particle mass was performed by an Aerosol Particle Mass analyzer – Scanning Mobility Particle Sizer (APM-SMPS) to obtain particle mass concentration and fractal dimension. Continuous aging of aerosol was observed in terms of atomic ratio (O/C), from 0.05 to 0.25 in 12 hours,more » underscoring the importance of multi-generational oxidation of low-volatile organic vapors emitted from diesel engine as the significant source of oxygenated SOA. Experimental conditions possibly have strong impacts on physical evolution of diesel particulates in a smog chamber. Higher particle effective densities were observed when raw exhaust was injected into a full bag as opposed to filling a bag with diluted exhaust using an ejector diluter. When longer transfer line was used for injecting diesel exhaust into the smog chamber, rapid particle coagulation was observed, leading to increasing particle volume concentration in dark while its mass concentration is decreasing.« less

Surviving With Smog and Smoke: Precision Interventions?

PubMed

Cai, Hua; Wang, Chen

2017-11-01

Despite continuous efforts of regional governmental agencies, air pollution remains a major threat to public health worldwide. In January 2017, a severe episode of smog similar to the Great Smog of 1952 occurred in London. The longest episode of Chinese haze also developed in Beijing, during which levels of particulate matter < 2.5 μm rose to 500 μg/m 3 . European smog and Chinese haze are associated with large numbers of premature deaths each year, at 400,000 and 1.2 million, respectively, primarily from respiratory diseases, cerebrovascular diseases, and ischemic heart diseases. In addition to air pollution, some are exposed to other harmful environmental factors, such as secondhand smoke. For countries with large populations of smokers, such as China, India, the United States, and Russia, surviving both smog and smoke is a serious problem. With novel genomic and epigenomic studies revealing air pollution- and smoking-induced mutational signatures and epigenetic editing in diseases such as lung cancer, it has become feasible to develop precision strategies for early intervention in the disease-causing pathways driven by the specific mutations or epigenetic regulations, or both. New therapies guided by gene-drug interactions and genomic biomarkers may also be developed. We discuss both perspectives regarding the urgent need to manage the toxic effects of smog and smoke for the benefit of global health and the novel concept of precision intervention to protect the exposed individuals when exposure to smog and secondhand smoke cannot be voluntarily avoided or easily modified. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Smog Obscures Chinese Coast

NASA Technical Reports Server (NTRS)

2002-01-01

Most of southeastern China has been covered by a thick greyish shroud of aerosol pollution over the last few weeks. The smog is so thick it is difficult to see the surface in some regions of this scene, acquired on January 7, 2002. The city of Hong Kong is the large brown cluster of pixels toward the lower lefthand corner of the image (indicated by the faint black box). The island of Taiwan, due east of mainland China, is also blanketed by the smog. This true-color image was captured by the Moderate-resolution Imaging Spectroradiometer (MODIS) sensor, flying aboard NASA's Terra satellite. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

Transformation of logwood combustion emissions in a smog chamber: formation of secondary organic aerosol and changes in the primary organic aerosol upon daytime and nighttime aging

NASA Astrophysics Data System (ADS)

Tiitta, Petri; Leskinen, Ari; Hao, Liqing; Yli-Pirilä, Pasi; Kortelainen, Miika; Grigonyte, Julija; Tissari, Jarkko; Lamberg, Heikki; Hartikainen, Anni; Kuuspalo, Kari; Kortelainen, Aki-Matti; Virtanen, Annele; Lehtinen, Kari E. J.; Komppula, Mika; Pieber, Simone; Prévôt, André S. H.; Onasch, Timothy B.; Worsnop, Douglas R.; Czech, Hendryk; Zimmermann, Ralf; Jokiniemi, Jorma; Sippula, Olli

2016-10-01

Organic aerosols (OA) derived from small-scale wood combustion emissions are not well represented by current emissions inventories and models, although they contribute substantially to the atmospheric particulate matter (PM) levels. In this work, a 29 m3 smog chamber in the ILMARI facility of the University of Eastern Finland was utilized to investigate the formation of secondary organic aerosol (SOA) from a small-scale modern masonry heater commonly used in northern Europe. Emissions were oxidatively aged in the smog chamber for a variety of dark (i.e., O3 and NO3) and UV (i.e., OH) conditions, with OH concentration levels of (0.5-5) × 106 molecules cm-3, achieving equivalent atmospheric aging of up to 18 h. An aerosol mass spectrometer characterized the direct OA emissions and the SOA formed from the combustion of three wood species (birch, beech and spruce) using two ignition processes (fast ignition with a VOC-to-NOx ratio of 3 and slow ignition with a ratio of 5).Dark and UV aging increased the SOA mass fraction with average SOA productions 2.0 times the initial OA mass loadings. SOA enhancement was found to be higher for the slow ignition compared with fast ignition conditions. Positive matrix factorization (PMF) was used to separate SOA, primary organic aerosol (POA) and their subgroups from the total OA mass spectra. PMF analysis identified two POA and three SOA factors that correlated with the three major oxidizers: ozone, the nitrate radical and the OH radical. Organonitrates (ONs) were observed to be emitted directly from the wood combustion and additionally formed during oxidation via NO3 radicals (dark aging), suggesting small-scale wood combustion may be a significant ON source. POA was oxidized after the ozone addition, forming aged POA, and after 7 h of aging more than 75 % of the original POA was transformed. This process may involve evaporation and homogeneous gas-phase oxidation as well as heterogeneous oxidation of particulate organic matter

Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber

NASA Astrophysics Data System (ADS)

Liu, T.; Wang, X.; Deng, W.; Hu, Q.; Ding, X.; Zhang, Y.; He, Q.; Zhang, Z.; Lü, S.; Bi, X.; Chen, J.; Yu, J.

2015-04-01

In China, fast increase in passenger vehicles has procured the growing concern about vehicle exhausts as an important source of anthropogenic secondary organic aerosols (SOA) in megacities hard-hit by haze. However, there are still no chamber simulation studies in China on SOA formation from vehicle exhausts. In this study, the SOA formation of emissions from two idling light-duty gasoline vehicles (LDGVs) (Euro 1 and Euro 4) in China was investigated in a 30 m3 smog chamber. Five photo-oxidation experiments were carried out at 25 °C with the relative humidity around 50%. After aging at an OH exposure of 5 × 106 molecules cm-3 h, the formed SOA was 12-259 times as high as primary OA (POA). The SOA production factors (PF) were 0.001-0.044 g kg-1 fuel, comparable with those from the previous studies at the quite similar OH exposure. This quite lower OH exposure than that in typical atmospheric condition might however lead to the underestimation of the SOA formation potential from LDGVs. Effective SOA yield data in this study were well fit by a one-product gas-particle partitioning model and quite lower than those of a previous study investigating SOA formation form three idling passenger vehicles (Euro 2-Euro 4). Traditional single-ring aromatic precursors and naphthalene could explain 51-90% of the formed SOA. Unspeciated species such as branched and cyclic alkanes might be the possible precursors for the unexplained SOA. A high-resolution time-of-flight aerosol mass spectrometer was used to characterize the chemical composition of SOA. The relationship between f43 (ratio of m/z 43, mostly C2H3O+, to the total signal in mass spectrum) and f44 (mostly CO2+) of the gasoline vehicle exhaust SOA is similar to the ambient semi-volatile oxygenated organic aerosol (SV-OOA). We plot the O : C and H : C molar ratios of SOA in a Van Krevelen diagram. The slopes of ΔH : C/ΔO : C ranged from -0.59 to -0.36, suggesting that the oxidation chemistry in these experiments was a

Smog exposure and host resistance to respiratory pathogens

EPA Science Inventory

The US EPA is evaluating the health effects of photochemical smog on respiratory, cardiovascular and metabolic health (https://www.epa.gov/air-research/secondary-organic-aerosol-soas-research). Smog exposure has been associated with an increased risk of allergy and decreased res...

Relationship between mortality and fine particles during Asian dust, smog-Asian dust, and smog days in Korea.

PubMed

Kim, Hyun-Sun; Kim, Dong-Sik; Kim, Ho; Yi, Seung-Muk

2012-01-01

This study examined the association between all-cause/cardiovascular mortality and PM(2.5) as related to Asian dust (AD), smog-AD, smog, and nonevent days and evaluated the differential risks according to specific events for mortality. The daily records of all-cause/cardiovascular mortality and PM(2.5) from March to May 2003-2006 in Seoul, Korea, were used as independent and dependent variables. Differences in the event effects were assessed using a time-series analysis. Both all-cause and cardiovascular mortalities were significantly associated with PM(2.5) during smog-AD and AD days only. Differences in chemical composition emerging during long-range transport to Korea may explain these observations, especially as regards secondary aerosol, metal-sulfate/or nitrate, and metallic components. These results suggest that exposure to PM(2.5) during specific events is differentially associated with human mortality and that changes in the chemical composition of PM(2.5), occurring during long-range transport, represent important factors in such differential effects on health.

Smog episodes, fine particulate pollution and mortality in China.

PubMed

Zhou, Maigeng; He, Guojun; Fan, Maoyong; Wang, Zhaoxi; Liu, Yang; Ma, Jing; Ma, Zongwei; Liu, Jiangmei; Liu, Yunning; Wang, Linhong; Liu, Yuanli

2015-01-01

Starting from early January 2013, northern China was hit by multiple prolonged and severe smog events which were characterized by extremely high-level concentrations of ambient fine particulate matter (PM2.5) with hourly peaks of PM2.5 over 800 µg/m(3). However, the consequences of this severe air pollution are largely unknown. This study investigates the acute effect of the smog episodes and PM2.5 on mortality for both urban and rural areas in northern China. We collected PM2.5, mortality, and meteorological data for 5 urban city districts and 2 rural counties in Beijing, Tianjin and Hebei Province of China from January 1, 2013 through December 31, 2013. We employed the generalized additive models to estimate the associations between smog episodes or PM2.5 and daily mortality for each district/county. Without any meteorological control, the smog episodes are positively and statistically significantly associated with mortality in 5 out of 7 districts/counties. However, the findings are sensitive to the meteorological factors. After controlling for temperature, humidity, dew point and wind, the statistical significance disappears in all urban districts. In contrast, the smog episodes are consistently and statistically significantly associated with higher total mortality and mortality from cardiovascular/respiratory diseases in the two rural counties. In Ji County, a smog episode is associated with 6.94% (95% Confidence Interval, -0.20 to 14.58) increase in overall mortality, and in Ci County it is associated with a 19.26% (95% CI, 6.66-33.34) increase in overall mortality. The smog episodes kill people primarily through its impact on cardiovascular and respiratory diseases. On average, a smog episode is associated with 11.66% (95% CI, 3.12-20.90) increase in cardiovascular and respiratory mortality in Ji County, and it is associated with a 22.23% (95% CI, 8.11-38.20) increase in cardiovascular and respiratory mortality in Ci County. A 10 μg/m(3) increase in PM2

Comparative cardiopulmonary effects of particulate matter- and ozone-enhanced smog atmospheres in mice

EPA Science Inventory

This study was conducted to compare the cardiac effects of particulate matter (PM)-enhanced and ozone(O3)-enhanced smog atmospheres in mice. We hypothesized that O3-enhanced smog would cause greater cardiac dysfunction than PM-enhanced smog due to the higher concentrations of irr...

Evaluation of Aromatic Oxidation Reactions in Seven Chemical Mechanisms with an Outdoor Chamber

EPA Science Inventory

Simulations using seven chemical mechanisms are intercompared against O₃, NO_x and hydrocarbon data from photooxidation experiments conducted at the University of North Carolina outdoor smog chamber. The mechanisms include CB4–2002, CB05, CB05-TU, a CB05 vari...

Differential cardiac effects in rats exposed to atmospheric smog generated from isoprene versus toluene

EPA Science Inventory

The results of this study demonstrate that atmospheric smog generated from both isoprene and toluene cause cardiac effects in rats. In addition, it appears that smog from toluene is more toxic in terms of cardiac arrhythmogenicity. Smog, which is a comple...

The health policy implications of individual adaptive behavior responses to smog pollution in urban China.

PubMed

Ban, Jie; Zhou, Lian; Zhang, Yi; Brooke Anderson, G; Li, Tiantian

2017-09-01

Smog pollution is a serious public health issue in urban China, where it is associated with public health through a range of respiratory and cardiovascular illnesses. Despite the negative health impacts of smog pollution, individual adaptive behaviors are poorly understood. This knowledge gap hinders the development of effective public policy to support and encourage the adoption of individual adaptive and mitigating behaviors to smog pollution. A questionnaire survey of 1141 randomly sampled individuals in a typical PM 2.5 -polluted Chinese city was designed to establish smog concerns and behavior changes during smog events. The results demonstrate a variety of behavior responses associated with risk perception, experience of smog, age, and gender of respondents. An understanding of these variations is critical to the development of effective public policy and ultimately to the improvement of public health in cities affected by smog. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tropospheric Ozone and Photochemical Smog

NASA Astrophysics Data System (ADS)

Sillman, S.

2003-12-01

The question of air quality in polluted regions represents one of the issues of geochemistry with direct implications for human well-being. Human health and well-being, along with the well-being of plants, animals, and agricultural crops, are dependent on the quality of air we breathe. Since the start of the industrial era, air quality has become a matter of major importance, especially in large cities or urbanized regions with heavy automobile traffic and industrial activity.Concern over air quality existed as far back as the 1600s. Originally, polluted air in cities resulted from the burning of wood or coal, largely as a source of heat. The industrial revolution in England saw a great increase in the use of coal in rapidly growing cities, both for industrial use and domestic heating. London suffered from devastating pollution events during the late 1800s and early 1900s, with thousands of excess deaths attributed to air pollution (Brimblecombe, 1987). With increasing use of coal, other instances also occurred in continental Europe and the USA. These events were caused by directly emitted pollutants (primary pollutants), including sulfur dioxide (SO2), carbon monoxide (CO), and particulates. They were especially acute in cities with northerly locations during fall and winter when sunlight is at a minimum. These original pollution events gave rise to the term "smog" (a combination of smoke and fog). Events of this type have become much less severe since the 1950s in Western Europe and the US, as natural gas replaced coal as the primary source of home heating, industrial smokestacks were designed to emit at higher altitudes (where dispersion is more rapid), and industries were required to install pollution control equipment.Beginning in the 1950s, a new type of pollution, photochemical smog, became a major concern. Photochemical smog consists of ozone (O3) and other closely related species ("secondary pollutants") that are produced photochemically from directly

Influence of vapor wall loss in laboratory chambers on yields of secondary organic aerosol

PubMed Central

Zhang, Xuan; Cappa, Christopher D.; Jathar, Shantanu H.; McVay, Renee C.; Ensberg, Joseph J.; Kleeman, Michael J.; Seinfeld, John H.

2014-01-01

Secondary organic aerosol (SOA) constitutes a major fraction of submicrometer atmospheric particulate matter. Quantitative simulation of SOA within air-quality and climate models—and its resulting impacts—depends on the translation of SOA formation observed in laboratory chambers into robust parameterizations. Worldwide data have been accumulating indicating that model predictions of SOA are substantially lower than ambient observations. Although possible explanations for this mismatch have been advanced, none has addressed the laboratory chamber data themselves. Losses of particles to the walls of chambers are routinely accounted for, but there has been little evaluation of the effects on SOA formation of losses of semivolatile vapors to chamber walls. Here, we experimentally demonstrate that such vapor losses can lead to substantially underestimated SOA formation, by factors as much as 4. Accounting for such losses has the clear potential to bring model predictions and observations of organic aerosol levels into much closer agreement. PMID:24711404

Simulations of photochemical smog formation in complex urban areas

NASA Astrophysics Data System (ADS)

Muilwijk, C.; Schrijvers, P. J. C.; Wuerz, S.; Kenjereš, S.

2016-12-01

In the present study we numerically investigated the dispersion of photochemical reactive pollutants in complex urban areas by applying an integrated Computational Fluid Dynamics (CFD) and Computational Reaction Dynamics (CRD) approach. To model chemical reactions involved in smog generation, the Generic Reaction Set (GRS) approach is used. The GRS model was selected since it does not require detailed modeling of a large set of reactive components. Smog formation is modeled first in the case of an intensive traffic emission, subjected to low to moderate wind conditions in an idealized two-dimensional street canyon with a building aspect ratio (height/width) of one. It is found that Reactive Organic Components (ROC) play an important role in the chemistry of smog formation. In contrast to the NOx/O3 photochemical steady state model that predicts a depletion of the (ground level) ozone, the GRS model predicts generation of ozone. Secondly, the effect of direct sunlight and shadow within the street canyon on the chemical reaction dynamics is investigated for three characteristic solar angles (morning, midday and afternoon). Large differences of up to one order of magnitude are found in the ozone production for different solar angles. As a proof of concept for real urban areas, the integrated CFD/CRD approach is applied for a real scale (1 × 1 km2) complex urban area (a district of the city of Rotterdam, The Netherlands) with high traffic emissions. The predicted pollutant concentration levels give realistic values that correspond to moderate to heavy smog. It is concluded that the integrated CFD/CRD method with the GRS model of chemical reactions is both accurate and numerically robust, and can be used for modeling of smog formation in complex urban areas.

DETERMINATION OF SECONDARY ORGANIC AEROSOL PRODUCTS FROM THE PHOTOOXIDATION OF TOLUENE AND THEIR IMPLICATIONS IN AMBIENT PM2.5

EPA Science Inventory

Laboratory study was carried out to investigate the secondary organic aerosol products from photooxidation of the aromatic hydrocarbon toluene. The laboratory experiments consisted of irradiating toluene/propylene/NOX/air mixtures in a smog chamber operated in the dynamic mode...

Free Air Quality Alerts Help New Englanders Prepare for Summer Smog Season

EPA Pesticide Factsheets

With the onset of warm summer weather, the USEPA advises New Englanders to be aware of the increased risk of ground-level ozone and fine particle air pollution (when combined, often referred to as smog), & take health precautions when smog levels are high.

Metagenomic profiling of ARGs in airborne particulate matters during a severe smog event.

PubMed

Hu, Jialin; Zhao, Fuzheng; Zhang, Xu-Xiang; Li, Kan; Li, Chaoran; Ye, Lin; Li, Mei

2018-02-15

Information is currently limited regarding the distribution of antibiotic resistance genes (ARGs) in smog and their correlations with airborne bacteria. This study characterized the diversity and abundance of ARGs in the particulate matters (PMs) of severe smog based on publicly available metagenomic data, and revealed the occurrence of 205 airborne ARG subtypes, including 31 dominant ones encoding resistance to 11 antibiotic types. Among the detectable ARGs, tetracycline, β-lactam and aminoglycoside resistance genes had the highest abundance, and smog and soil had similar composition characteristics of ARGs. During the smog event, the total abundance of airborne ARGs ranged from 4.90 to 38.07ppm in PM 2.5 samples, and from 7.61 to 38.49ppm in PM 10 samples, which were 1.6-7.7 times and 2.1-5.1 times of those in the non-smog day, respectively. The airborne ARGs showed complicated co-occurrence patterns, which were heavily influenced by the interaction of bacterial community, and physicochemical and meteorological factors. Lactobacillus and sulfonamide resistance gene sul1 were determined as keystones in the co-occurrence network of microbial taxa and airborne ARGs. The results may help to understand the distribution patterns of ARGs in smog for the potential health risk evaluation. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessing the features of extreme smog in China and the differentiated treatment strategy

NASA Astrophysics Data System (ADS)

Deng, Lu; Zhang, Zhengjun

2018-01-01

Extreme smog can have potentially harmful effects on human health, the economy and daily life. However, the average (mean) values do not provide strategically useful information on the hazard analysis and control of extreme smog. This article investigates China's smog extremes by applying extreme value analysis to hourly PM2.5 data from 2014 to 2016 obtained from monitoring stations across China. By fitting a generalized extreme value (GEV) distribution to exceedances over a station-specific extreme smog level at each monitoring location, all study stations are grouped into eight different categories based on the estimated mean and shape parameter values of fitted GEV distributions. The extreme features characterized by the mean of the fitted extreme value distribution, the maximum frequency and the tail index of extreme smog at each location are analysed. These features can provide useful information for central/local government to conduct differentiated treatments in cities within different categories and conduct similar prevention goals and control strategies among those cities belonging to the same category in a range of areas. Furthermore, hazardous hours, breaking probability and the 1-year return level of each station are demonstrated by category, based on which the future control and reduction targets of extreme smog are proposed for the cities of Beijing, Tianjin and Hebei as an example.

Secondary organic aerosol formation from photochemical aging of light-duty gasoline vehicle exhausts in a smog chamber

NASA Astrophysics Data System (ADS)

Liu, T.; Wang, X.; Deng, W.; Hu, Q.; Ding, X.; Zhang, Y.; He, Q.; Zhang, Z.; Lü, S.; Bi, X.; Chen, J.; Yu, J.

2015-08-01

In China, a rapid increase in passenger vehicles has led to the growing concern of vehicle exhaust as an important source of anthropogenic secondary organic aerosol (SOA) in megacities hard hit by haze. In this study, the SOA formation of emissions from two idling light-duty gasoline vehicles (LDGVs) (Euro 1 and Euro 4) operated in China was investigated in a 30 m3 smog chamber. Five photo-oxidation experiments were carried out at 25 °C with relative humidity at around 50 %. After aging at an OH exposure of 5 × 106 molecules cm-3 h, the formed SOA was 12-259 times as high as primary organic aerosol (POA). The SOA production factors (PF) were 0.001-0.044 g kg-1 fuel, comparable with those from the previous studies at comparable OH exposure. This quite lower OH exposure than that in typical atmospheric conditions might however lead to the underestimation of the SOA formation potential from LDGVs. Effective SOA yields in this study were well fit by a one-product gas-particle partitioning model but quite lower than those of a previous study investigating SOA formation from three idling passenger vehicles (Euro 2-4). Traditional single-ring aromatic precursors and naphthalene could explain 51-90 % of the formed SOA. Unspeciated species such as branched and cyclic alkanes might be the possible precursors for the unexplained SOA. A high-resolution time-of-flight aerosol mass spectrometer was used to characterize the chemical composition of SOA. The relationship between f43 (ratio of m/z 43, mostly C2H3O+, to the total signal in mass spectrum) and f44 (mostly CO2+) of the gasoline vehicle exhaust SOA is similar to the ambient semi-volatile oxygenated organic aerosol (SV-OOA). We plot the O : C and H : C molar ratios of SOA in a Van Krevelen diagram. The slopes of ΔH : C / ΔO : C ranged from -0.59 to -0.36, suggesting that the oxidation chemistry in these experiments was a combination of carboxylic acid and alcohol/peroxide formation.

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

EPA Science Inventory

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

Reverberation Chamber Uniformity Validation and Radiated Susceptibility Test Procedures for the NASA High Intensity Radiated Fields Laboratory

NASA Technical Reports Server (NTRS)

Koppen, Sandra V.; Nguyen, Truong X.; Mielnik, John J.

2010-01-01

The NASA Langley Research Center's High Intensity Radiated Fields Laboratory has developed a capability based on the RTCA/DO-160F Section 20 guidelines for radiated electromagnetic susceptibility testing in reverberation chambers. Phase 1 of the test procedure utilizes mode-tuned stirrer techniques and E-field probe measurements to validate chamber uniformity, determines chamber loading effects, and defines a radiated susceptibility test process. The test procedure is segmented into numbered operations that are largely software controlled. This document is intended as a laboratory test reference and includes diagrams of test setups, equipment lists, as well as test results and analysis. Phase 2 of development is discussed.

Data Smog: Surviving the Info Glut.

ERIC Educational Resources Information Center

Shenk, David

1997-01-01

While the ability to churn out information has exceeded our ability to process it, the goal of the information industry is to convince us that whatever we have is not enough. This article examines the drawbacks of the information age (including "data smog" and "information anxiety") and makes suggestions for limiting exposure…

A single exposure to photochemical smog causes airway irritation and cardiac dysrhythmia in mice

EPA Science Inventory

The data presented here shows that a single exposure to photochemical smog causes airway irritation and cardiac dysrhythmia in mice. Smog, which is a complex mixture of particulate matter and gaseous irritants (ozone, sulfur dioxide, reactive aldehydes), as well as components whi...

SMOG 2: A Versatile Software Package for Generating Structure-Based Models.

PubMed

Noel, Jeffrey K; Levi, Mariana; Raghunathan, Mohit; Lammert, Heiko; Hayes, Ryan L; Onuchic, José N; Whitford, Paul C

2016-03-01

Molecular dynamics simulations with coarse-grained or simplified Hamiltonians have proven to be an effective means of capturing the functionally important long-time and large-length scale motions of proteins and RNAs. Originally developed in the context of protein folding, structure-based models (SBMs) have since been extended to probe a diverse range of biomolecular processes, spanning from protein and RNA folding to functional transitions in molecular machines. The hallmark feature of a structure-based model is that part, or all, of the potential energy function is defined by a known structure. Within this general class of models, there exist many possible variations in resolution and energetic composition. SMOG 2 is a downloadable software package that reads user-designated structural information and user-defined energy definitions, in order to produce the files necessary to use SBMs with high performance molecular dynamics packages: GROMACS and NAMD. SMOG 2 is bundled with XML-formatted template files that define commonly used SBMs, and it can process template files that are altered according to the needs of each user. This computational infrastructure also allows for experimental or bioinformatics-derived restraints or novel structural features to be included, e.g. novel ligands, prosthetic groups and post-translational/transcriptional modifications. The code and user guide can be downloaded at http://smog-server.org/smog2.

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

NASA Astrophysics Data System (ADS)

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

2015-09-01

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

Smog chamber study on aging of combustion soot in isoprene/SO2/NOx system: Changes of mass, size, effective density, morphology and mixing state

NASA Astrophysics Data System (ADS)

Li, Kangwei; Chen, Linghong; Han, Ke; Lv, Biao; Bao, Kaiji; Wu, Xuecheng; Gao, Xiang; Cen, Kefa

2017-02-01

Atmospheric soot aging process is always accompanied by secondary particle formation, which is a comprehensive environmental issue that deserves great attention. On one hand, aging of primary soot could change its own physicochemical properties; on the other hand, complex air pollution caused by pollutant emission from various sources (e.g., vehicle exhausts, coal-fired flue gases and biogenic VOCs emission) may contribute to secondary particle formation onto primary particle surface. In this study, aging of combustion soot in isoprene/SO2/NOx system was investigated under controlled laboratory conditions in several smog chamber experiments. During the evolution of soot, several physical properties such as mass, size, effective density, morphology and mixing state were determined simultaneously by an integrated aerosol analytical system of Scanning Mobility Particle Sizer (SMPS), Differential Mobility Analyzer-Aerosol Particle Mass Analyzer-Condensation Particle Counter (DMA-APM-CPC) and Transmission Electron Microscopy coupled with Energy-dispersive X-ray Spectrometry (TEM/EDX) techniques. Here, based on the experimental results of soot aging under different gas-phase composition and relative humidity (RH), we firstly proposed possible aging pathways of soot in isoprene/SO2/NOx system. A synergetic effect was speculated to exist between SO2 and isoprene on soot aging process, which led to more secondary particle formation. At the same time, TEM/EDX analysis showed that a competitive mechanism between H2SO4(g) and isoprene oxidation vapor may exist: H2SO4(g) firstly condensed onto fresh soot, then an acceleration of isoprene oxidation products formed onto H2SO4 pre-coated soot. In isoprene/SO2/NOx system, high RH conditions could contribute to soot aging and new particle formation. The changes of effective density and dynamic shape factor of soot also indicated that high RH conditions could accelerate soot aging process, and led chain-like soot into more spherical

The Donora Smog Revisited: 70 Years After the Event That Inspired the Clean Air Act

PubMed Central

Burgess, Jefferey L.; Abbott, Mark B.

2018-01-01

At a storefront museum approximately 25 miles southeast of Pittsburgh, Pennsylvania, a sign reads, “Clean Air Started Here.” This is not hyperbole. At the end of October 1948, the communities of Donora and Webster in Pennsylvania were visited by a smog that changed the face of environmental protection in the United States. Conservative estimates showed that 20 individuals died, while an additional 5900—43% of the population of Donora—were affected by the smog. This event led to the first large-scale epidemiological investigation of an environmental health disaster in the United States. Questions remain about the long-term effects of the smog, because higher rates of cardiovascular disease and cancer than were expected were observed in the region in the decade following the smog. Recent work has suggested that environmental contaminants from a bygone era in Donora might have an impact even today. In addition, reports regarding air pollution have indicated that levels of pollutants similar to those estimated to have occurred in Donora are currently present in some rapidly industrializing regions of China and India. Seventy years after the smog, this event still resonates. PMID:29698099

Characterization and Simulation of a New Design Parallel-Plate Ionization Chamber for CT Dosimetry at Calibration Laboratories

NASA Astrophysics Data System (ADS)

Perini, Ana P.; Neves, Lucio P.; Maia, Ana F.; Caldas, Linda V. E.

2013-12-01

In this work, a new extended-length parallel-plate ionization chamber was tested in the standard radiation qualities for computed tomography established according to the half-value layers defined at the IEC 61267 standard, at the Calibration Laboratory of the Instituto de Pesquisas Energéticas e Nucleares (IPEN). The experimental characterization was made following the IEC 61674 standard recommendations. The experimental results obtained with the ionization chamber studied in this work were compared to those obtained with a commercial pencil ionization chamber, showing a good agreement. With the use of the PENELOPE Monte Carlo code, simulations were undertaken to evaluate the influence of the cables, insulator, PMMA body, collecting electrode, guard ring, screws, as well as different materials and geometrical arrangements, on the energy deposited on the ionization chamber sensitive volume. The maximum influence observed was 13.3% for the collecting electrode, and regarding the use of different materials and design, the substitutions showed that the original project presented the most suitable configuration. The experimental and simulated results obtained in this work show that this ionization chamber has appropriate characteristics to be used at calibration laboratories, for dosimetry in standard computed tomography and diagnostic radiology quality beams.

Mobile Smog Simulator: New Capabilities to Study Urban Mixtures

EPA Pesticide Factsheets

A smog simulator developed by EPA scientists and engineers has unique capabilities that will provide information for assessing the health impacts of relevant multipollutant atmospheres and identify contributions of specific sources.

Development of SMOG-Cro readability formula for healthcare communication and patient education.

PubMed

Brangan, Sanja

2015-03-01

Effective communication shows a positive impact on patient satisfaction, compliance and medical outcomes, at the same time reducing the healthcare costs. Written information for patients needs to correspond to health literacy levels of the intended audiences. Readability formulas correlate well with the reading and comprehension tests but are considered an easier and quicker method to estimate a text difficulty. SMOG readability formula designed for English language needs to be modified if used for texts in other languages. The aim of this study was to develop a readability formula based on SMOG, that could be used to estimate text difficulty of written materials for patients in Croatian language. Contras- tive analysis of English and Croatian language covering a corpus of almost 100,000 running words showed clear linguis- tic differences in the number of polysyllabic words. The new formula, named SMOG-Cro, is presented as an equation: SMOG-Cro = 2 + √4+ syllables, with the score showing the number of years of education a person needs to be able to understand a piece of writing. The presented methodology could help in the development of readability formulas for other languages. We hope the results of this study are soon put into practice for more effective healthcare communication and patient education, and for development of a health literacy assessment tool in Croatian language.

Effect of nitrogen oxides (NO and NO2) and toluene on SO2 photooxidation, nucleation and growth: A smog chamber study

NASA Astrophysics Data System (ADS)

Li, Kangwei; Chen, Linghong; White, Stephen J.; Han, Ke; Lv, Biao; Bao, Kaiji; Wu, Xuecheng; Gao, Xiang; Azzi, Merched; Cen, Kefa

2017-08-01

The formation and growth of new particles has recently been shown to have a significant influence on Chinese haze pollution, and sulfuric acid has long been recognized as a major contributor to new particle formation. In this study, four comparison groups of experiments related to SO2 photooxidation, as well as aerosol nucleation and growth, have been conducted in the CAPS-ZJU (Complex Air Pollution Study-Zhejiang University) smog chamber. These were conducted either under SO2/NOx or SO2/toluene gas-phase environments in the absence of seed particles. During aerosol nucleation and growth process, several physical properties such as mass, size and effective density were measured simultaneously by Scanning Mobility Particle Sizer (SMPS) and Differential Mobility Analyzer-Aerosol Particle Mass Analyzer-Condensation Particle Counter (DMA-APM-CPC). The effective density of new particles decreased from 1.8 to 1.35 g/cm3 as the particle size increased from 20 to 65 nm. The single particle mass showed good power-law relationship with mobility diameter, with an average mass-mobility exponent of 2.885. A new algorithm and a reference density of 1.38 g/cm3 based on size-resolved single particle mass (SPM) were proposed to calculate the mass concentration of new particles. Two methods based on Log Normal and Max Concentration were applied to derive particle growth rate (GR), and data merging from both methods was implemented to decrease calculation uncertainty. Meanwhile, both continuous nucleation and inhibition of further growth in sub-20 nm size range were observed in different experiments depending on composition, and possible reasons were analyzed. The presence of NO was found to suppress nucleation and subsequent aerosol growth; while the presence of NO2 or toluene promoted it. It was concluded that decreasing NOx (NO or NO2) or increasing toluene may promote SO2 photooxidation, nucleation and subsequent aerosol growth, all of which is significant for deeper

Development of a large-scale isolation chamber system for the safe and humane care of medium-sized laboratory animals harboring infectious diseases*

PubMed Central

Pan, Xin; Qi, Jian-cheng; Long, Ming; Liang, Hao; Chen, Xiao; Li, Han; Li, Guang-bo; Zheng, Hao

2010-01-01

The close phylogenetic relationship between humans and non-human primates makes non-human primates an irreplaceable model for the study of human infectious diseases. In this study, we describe the development of a large-scale automatic multi-functional isolation chamber for use with medium-sized laboratory animals carrying infectious diseases. The isolation chamber, including the transfer chain, disinfection chain, negative air pressure isolation system, animal welfare system, and the automated system, is designed to meet all biological safety standards. To create an internal chamber environment that is completely isolated from the exterior, variable frequency drive blowers are used in the air-intake and air-exhaust system, precisely controlling the filtered air flow and providing an air-barrier protection. A double door transfer port is used to transfer material between the interior of the isolation chamber and the outside. A peracetic acid sterilizer and its associated pipeline allow for complete disinfection of the isolation chamber. All of the isolation chamber parameters can be automatically controlled by a programmable computerized menu, allowing for work with different animals in different-sized cages depending on the research project. The large-scale multi-functional isolation chamber provides a useful and safe system for working with infectious medium-sized laboratory animals in high-level bio-safety laboratories. PMID:20872984

SECONDARY ORGANIC AEROSOL FORMATION FROM THE OXIDATION OF AROMATIC HYDROCARBONS IN THE PRESENCE OF DRY SUBMICRON AMMONIUM SULFATE AEROSOL

EPA Science Inventory

A laboratory study was conducted to examine formation of secondary organic aerosols. A smog chamber system was developed for studying gas-aerosol interactions in a dynamic flow reactor. These experiments were conducted to investigate the fate of gas and aerosol phase compounds ...

Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: Explicit modeling of SOA formation from alkane and alkene oxidation

DOE PAGES

La, Y. S.; Camredon, M.; Ziemann, P. J.; ...

2016-02-08

Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool, which explicitly represents SOA formation and gas–wall partitioning. The model was compared with 41 smog chambermore » experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C 12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NO x conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas–wall mass transfer, the vapor pressure of the species and the duration of the experiments. Furthermore, this work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.« less

Smog Yellows Taj Mahal

NASA Technical Reports Server (NTRS)

2007-01-01

Built as a monument to the favorite wife of the Mughal Emperor Shah Jahan, the Taj Mahal has watched over the city of Agra, India, since the mid-seventeenth century with its pillars of gleaming white marble. By the spring of 2007, however, one of the world's most visited landmarks was turning yellow, and a panel of India's parliament had little trouble identifying the culprit: pollution. The panel blamed particles of soot and dirt suspended high in the atmosphere for the Taj Mahal's dinginess. The Taj Mahal's home, Agra, sits not far from the base of the Himalaya, and smog regularly collects along the southern side of the mountain range. On May 16, 2007, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image of the area around Agra, India. The closeup image shows the immediate vicinity of the Taj Majal. The larger image shows the surrounding area. In both pictures, dingy, gray-beige haze obscures the satellite's view of the land surface. India had tried to minimize the adverse impact of air pollution on the famous landmark. According to the BBC, in the late 1990s, India's Supreme Court ordered the closure of thousands of iron foundries and kilns that had belched smoke near the monument. Many of the 3 million tourists who visited the Taj Majal each year approached the monument on horse-drawn carriages or battery-operated buses as fossil-fuel-powered vehicles could not drive within 2 kilometers (1.5 miles). Since those efforts have failed to save the Taj Majal's complexion, Indian officials have considered applying a cleansing mud pack to the monument's surface to draw out the dirt. As India industrializes, smog results, and the Taj Mahal's gleaming whiteness is only one casualty. Pollution has been blamed for a decrease in Indian rice harvests, which had soared during the 'Green Revolution' of the 1960s and 1970s. Haze and dust also appear to bring on the region's monsoon rains earlier than normal.

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

A small whole-body exposure chamber for laboratory use.

PubMed

O'Shaughnessy, Patrick T; Achutan, Chandran; O'Neill, Marsha E; Thorne, Peter S

2003-03-01

With the development of transgenic and specialized mouse strains, there is an increased need for inhalation exposure systems designed for smaller exposure groups. An inhalation exposure chamber, designed specifically for the exposure of up to 40 mice, was characterized. The chamber was fabricated from 0.32-cm-thick ((1)/(8)-in) aluminum sheets with outside dimensions of 61 cm long by 32 cm high by 34 cm deep, resulting in an internal volume of 65 L. Two stainless-steel open-mesh cages, separated by an absorbent barrier, can be stacked within the central portion of the chamber. Access is provided through a gasketed door with a safety-glass face. Tests were performed to determine the chamber leakage rate, degree of mixing, and spatial variation of two aerosols within the chamber. Results indicated that the fractional leakage rate was 0.0003 min(-1), well below a reported criterion for an operating chamber. Chamber operation gave similar mixing performance with, or without, use of an interior fan. For aerosols with a mass median aerodynamic diameter (MMAD) of 2.56 micro m and 3.14 micro m, the spatial variation of particulate matter concentration resulted in coefficients of variation (CVs) of 4.8% and 11.0%, respectively. These CV values are comparable to those obtained from similar studies involving other inhalation exposure chambers.

Microbiological Diversity Demonstrates the Potential which Collaboratively Metabolize Nitrogen Oxides ( NOx) under Smog Environmental Stress

NASA Astrophysics Data System (ADS)

Chen, X. Z.; Zhao, X. H.; Chen, X. P.

2018-03-01

Recently, smoggy weather has become a daily in large part of China because of rapidly economic growth and accelerative urbanization. Stressed on the smoggy situation and economic growth, the green and environment-friendly technology is necessary to reduce or eliminate the smog and promote the sustainable development of economy. Previous studies had confirmed that nitrogen oxides ( NOx ) is one of crucial factors which forms smog. Microorganisms have the advantages of quickly growth and reproduction and metabolic diversity which can collaboratively Metabolize various NOx. This study will design a kind of bacteria & algae cultivation system which can metabolize collaboratively nitrogen oxides in air and intervene in the local nitrogen cycle. Furthermore, the nitrogen oxides can be transformed into nitrogen gas or assembled in protein in microorganism cell by regulating the microorganism types and quantities and metabolic pathways in the system. Finally, the smog will be alleviated or eliminated because of reduction of nitrogen oxides emission. This study will produce the green developmental methodology.

Comparing the field and laboratory emission cell (FLEC) with traditional emissions testing chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roache, N.F.; Guo, Z.; Fortmann, R.

1996-12-31

A series of tests was designed to evaluate the performance of the field and laboratory emission cell (FLEC) as applied to the testing of emissions from two indoor coating materials, floor wax and latex paint. These tests included validation of the repeatability of the test method, evaluation of the effect of different air velocities on source emissions, and a comparison of FLEC versus small chamber characterization of emissions. The FLEC exhibited good repeatability in characterization of emissions when applied to both sources under identical conditions. Tests with different air velocities showed significant effects on the emissions from latex paint, yetmore » little effect on emissions from the floor wax. Comparisons of data from the FLEC and small chamber show good correlation for measurements involving floor wax, but less favorable results for emissions from latex paint. The procedures and findings are discussed; conclusions are limited and include emphasis on the need for additional study and development of a standard method.« less

Image quality, meteorological optical range, and fog particulate number evaluation using the Sandia National Laboratories fog chamber

DOE PAGES

Birch, Gabriel C.; Woo, Bryana L.; Sanchez, Andres L.; ...

2017-08-24

The evaluation of optical system performance in fog conditions typically requires field testing. This can be challenging due to the unpredictable nature of fog generation and the temporal and spatial nonuniformity of the phenomenon itself. We describe the Sandia National Laboratories fog chamber, a new test facility that enables the repeatable generation of fog within a 55 m×3 m×3 m (L×W×H) environment, and demonstrate the fog chamber through a series of optical tests. These tests are performed to evaluate system image quality, determine meteorological optical range (MOR), and measure the number of particles in the atmosphere. Relationships between typical opticalmore » quality metrics, MOR values, and total number of fog particles are described using the data obtained from the fog chamber and repeated over a series of three tests.« less

Image quality, meteorological optical range, and fog particulate number evaluation using the Sandia National Laboratories fog chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birch, Gabriel C.; Woo, Bryana L.; Sanchez, Andres L.

The evaluation of optical system performance in fog conditions typically requires field testing. This can be challenging due to the unpredictable nature of fog generation and the temporal and spatial nonuniformity of the phenomenon itself. We describe the Sandia National Laboratories fog chamber, a new test facility that enables the repeatable generation of fog within a 55 m×3 m×3 m (L×W×H) environment, and demonstrate the fog chamber through a series of optical tests. These tests are performed to evaluate system image quality, determine meteorological optical range (MOR), and measure the number of particles in the atmosphere. Relationships between typical opticalmore » quality metrics, MOR values, and total number of fog particles are described using the data obtained from the fog chamber and repeated over a series of three tests.« less

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

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

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

Effects of Isoprene- and Toluene-Generated Smog on Allergic Inflammation in Mice

EPA Science Inventory

Reactions of organic compounds with nitric oxide (NO) and sunlight produce complex mixtures of pollutants including secondary organic aerosol (SOA), ozone (O3), nitrogen dioxide (NO2), and reactive aldehydes. The health effects of these photochemical smog mixtures in susceptible ...

Development and Application of a Novel Environmental Preference Chamber for Assessing Responses of Laboratory Mice to Atmospheric Ammonia

PubMed Central

Green, Angela R; Wathes, Christopher M; Demmers, Theo GM; Clark, Judy MacArthur; Xin, Hongwei

2008-01-01

A novel environmental preference chamber (EPC) was developed and used to assess responses of laboratory mice to atmospheric ammonia. The EPC features 1) a test chamber with 4 individually ventilated, mutually accessible compartments; b) automated tracking of mouse movements by using paired infrared sensors; c) identification of individual mice by using photosensors; d) monitoring and regulation of the NH3 concentration in each compartment; and e) personal-computer–based data acquisition. In an initial preference study with the EPC, 4 groups of 4 laboratory mice (BALB/c/Bkl; body weight, 13.4 to 18.4 g) were each given a choice among 4 NH3 concentrations (mean ± SE) of 4 ± 2, 30 ± 2, 56 ± 4, and 110 ± 6 ppm for 2 d after a 2-d familiarization period. Once trained to use the intercompartment tunnels, the mice made extensive use of the EPC, with each group making more than 2000 intercompartment movements during 48 h. Video recording verified the results of the automatic tracking system, which detected and correctly determined mouse location for 79% of the moves. The use of photosensors proved to be ineffective in recognizing individual mice. Although the EPC would benefit from refinement and further development, it simplified analysis of locomotion behavioral data. Results of the preference study indicated that the mice exhibited no clear preference for, or aversion to, any of the experimental concentrations of ammonia and that the mice clearly preferred the upper 2 compartments of the chamber over the lower 2 compartments. Further investigation should be conducted to verify these preliminary results and explore other preferences of laboratory mice for environmental conditions and resources. PMID:18351722

Design and laboratory testing of a chamber device to measure total flux of volatile organic compounds from the unsaturated zone under natural conditions.

PubMed

Tillman, Fred D; Smith, James A

2004-11-01

To determine if an aquifer contaminated with volatile organic compounds (VOCs) has potential for natural remediation, all natural processes affecting the fate and transport of VOCs in the subsurface must be identified and quantified. This research addresses the quantification of air-phase volatile organic compounds (VOCs) leaving the unsaturated zone soil gas and entering the atmosphere-including the additional flux provided by advective soil-gas movement induced by barometric pumping. A simple and easy-to-use device for measuring VOC flux under natural conditions is presented. The vertical flux chamber (VFC) was designed using numerical simulations and evaluated in the laboratory. Mass-balance numerical simulations based on continuously stirred tank reactor equations (CSTR) provided information on flux measurement performance of several sampling configurations with the final chamber configuration measuring greater than 96% of model-simulated fluxes. A laboratory device was constructed to evaluate the flux chamber under both diffusion-only and advection-plus-diffusion transport conditions. The flux chamber measured an average of 82% of 15 diffusion-only fluxes and an average of 95% of 15 additional advection-plus-diffusion flux experiments. The vertical flux chamber has the capability of providing reliable measurement of VOC flux from the unsaturated zone under both diffusion and advection transport conditions.

STUDY USING A THREE-DIMENSIONAL SMOG FORMATION MODEL UNDER CONDITIONS OF COMPLEX FLOW

EPA Science Inventory

To clarify the photochemical smog formation mechanisms under conditions of complex flow, the SAI Urban Airshed Model was evaluated using a 1981 field observed data base. In the Tokyo Metropolitan Area higher O3 concentrations are usually observed near the shore in the morning. As...

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

12. View north of Tropic Chamber. Natick Research & ...

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

12. View north of Tropic Chamber. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

13. View south of Arctic Chamber. Natick Research & ...

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

13. View south of Arctic Chamber. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

A new tool for laboratory studies on volatilization: extension of applicability of the photovolatility chamber.

PubMed

Wolters, André; Kromer, Thomas; Linnemann, Volker; Schäffer, Andreas; Vereecken, Harry

2003-04-01

Volatilization from soil and plant surfaces after application is an important source of pesticide residues to the atmosphere. The laboratory photovolatility chamber allows the simultaneous measurement of volatilization and photodegradation of 14C-labeled pesticides under controlled climatic conditions. Both continuous air sampling, which quantifies volatile organic compounds and 14CO2 separately, and the detection of surface-located residues allow for a mass balance of radioactivity. The setup of the photovolatility chamber was optimized, and additional sensors were installed to characterize the influence of soil moisture, soil temperature, and evaporation on volatilization. The modified flow profile in the glass dome of the chamber arising from the use of a high-performance metal bellows pump was measured. Diminished air velocity near the soil surface and a wind velocity of 0.2 m/s in 3 cm height allowed the requirements of the German guideline on assessing pesticide volatilization for registration purposes to be fulfilled. Determination of soil moisture profiles of the upper soil layer illustrated that defined water content in the soil up to a depth of 4 cm could be achieved by water saturation of air. Cumulative volatilization of [phenyl-UL-14C]parathion-methyl ranged from 2.4% under dry conditions to 32.9% under moist conditions and revealed the clear dependence of volatilization on the water content in the top layer.

Concentration Variations in Particulate Matter in Seoul Associated with Asian Dust and Smog Episodes

DOE PAGES

Ghim, Young Sung; Kim, Jin Young; Chang, Young -Soo

2017-01-01

In this study, particulate species were measured in April–May 2003 at two sites, one in the megacity of Seoul and the other in the Deokjeok Island to the west of Seoul, to examine the effects of long-range transport under the influence of prevailing westerlies. The effects of Asian dust were observed in April, and a severe smog episode occurred in late May. During May, all air pollutants showed negative correlations with wind speed at Seoul, particularly for NO 2 and CO, a large proportion of which result from vehicle emissions. SO 4 2– continued to increase in association with anmore » inflow of air pollutants from China with heavy use of coal, with fluctuations depending on wind speed. The smog episode in late May occurred as emissions from Siberian forest fires were superimposed on pollutant inflows from China that had persisted since early May and local emissions accumulated under stagnant conditions. During the episode, Siberian forest fires increased K + while local emissions primarily from vehicles increased NO 3 –, OC, and EC. The effects of an inflow of air pollutants from the outside were significant at Deokjeok, with small local emissions, resulting in substantial increases in Ca 2+ during the Asian dust event and SO 4 2– during the smog episode, compared to those at Seoul. Because both sites were strongly influenced by the effects of long-range transport in May, PM 2.5 along with SO 4 2– and K + exhibited a strong correlation between Seoul and Deokjeok.« less

Laboratory Measurements of Isoprene-Derived Nitrates Using TD-LIF

NASA Astrophysics Data System (ADS)

Cohen, R.; Perring, A.; Wooldridge, P.; Shepson, P.; Lockwood, A.; Hill, K.; Moffat, C.; Mielke, L.; Cavender, A.; Stevens, P.; Dusanter, S.; Vimal, D.; Wisthaler, A.; Graus, M.

2006-12-01

Isoprene represents the largest flux of reactive non-methane hydrocarbon to the atmosphere and the production of isoprene-derived nitrates is currently one of the major controversies in nitrogen oxide chemistry. Alkyl and multifunctional nitrates (ΣANs), measured by Thermal Dissociation Laser Induced Fluorescence (TD-LIF), have been observed as a significant NOy component during many ground-based and airborne field experiments. A strong hypothesis is that many of these nitrates, especially in forest- impacted environments, are isoprene-derived. We present smog chamber measurements (made at Purdue University in June of 2006) of ΣANs, produced through both NO3 and OH-initiated oxidation of isoprene. Isoprene, OH, HO2, NO, NO2, NOy, PAN, HNO3 and speciated first generation isoprene nitrates were also measured simultaneously and chamber chemistry was subsequently modeled. We compare these measurements with previous measurements of isoprene nitrate yields and examine the relative contribution of secondary nitrates to the measured total organic nitrate concentrations.

11. Detail view west from airlock chamber of typical refrigerator ...

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

11. Detail view west from airlock chamber of typical refrigerator door into Trophic Chamber. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

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

PubMed

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

2012-12-31

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

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

Protective effects of edaravone combined puerarin on inhalation lung injury induced by black gunpowder smog.

PubMed

Wang, Zhengguan; Li, Ruibing; Liu, Yifan; Liu, Xiaoting; Chen, Wenyan; Xu, Shumin; Guo, Yuni; Duan, Jinyang; Chen, Yihong; Wang, Chengbin

2015-05-01

The present study aimed to investigate the combined effects of puerarin with edaravone on inhalation lung injury induced by black gunpowder smog. Male Wistar rats were divided into five groups (control group, edaravone group, puerarin group, edaravone combined with puerarin group and inhalation group). The severity of pulmonary injuries was evaluated after inducing acute lung injury. Arterial blood gas, inflammatory cytokines, biochemical, parameters, cell counting, W/D weight ratio and histopathology were analyzed. Results in lung tissues, either edaravone or puerarin treatment alone showed significant protective effects against neutrophil infiltration and tissue injury, as demonstrated by myeloperoxidase activity and histopathological analysis (all p<0.05). In addition, combined treatment with both edaravone and puerarin demonstrated additive protective effects on smog-induced lung injury, compared with single treatment. Combination of edaravone and puerarin shows promise as a new treatment option for acute lung injury/acute respiratory distress syndrome patients. Copyright © 2015 Elsevier B.V. All rights reserved.

PHOTOCHEMICAL PRODUCTS IN URBAN MIXTURES ENHANCE INFLAMMATORY RESPONSES IN LUNG CELLS

EPA Science Inventory

Complex urban air mixtures that realistically mimic urban smog can be generated for investigating adverse health effects. "Smog chambers" have been used for over 30 yr to conduct experiments for developing and testing photochemical models that predict ambient ozone (O(3)) concent...

National Ignition Facility Target Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 twomore » 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

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.

17. View northwest of Tropic Chamber refrigeration equipment, in machine ...

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

17. View northwest of Tropic Chamber refrigeration equipment, in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

Temperature and humidity control in indirect calorimeter chambers

USDA-ARS?s Scientific Manuscript database

A three-chamber, indirect calorimeter has been a part of the Environmental Laboratory at the U.S. Meat Animal Research Center (MARC) for over 25 yr. Corrosion of the animal chambers and unreliable temperature control forced either major repairs or complete replacement. There is a strong demand for...

19. View northwest of Tropic Chamber reciprocal compressors (typical), in ...

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

19. View northwest of Tropic Chamber reciprocal compressors (typical), in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

1. View southeast of Climatic Chambers Building from roof of ...

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

1. View southeast of Climatic Chambers Building from roof of Research Building. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

Smog episodes in the Lodz agglomeration in the years 2014-17

NASA Astrophysics Data System (ADS)

Wielgosiński, Grzegorz; Czerwińska, Justyna; Namiecińska, Olga; Cichowicz, Robert

2018-01-01

In recent years, in the winter season we are alarmed about the poor air quality in Poland and significantly exceeded permissible concentrations of certain pollutants, especially PM10 and PM2.5, which are a result of so-called low emissions. The authors analyze smog episodes in the Lodz agglomeration by comparing the recorded values of selected pollutant concentrations at monitoring stations of the Regional Inspectorate for Environmental Protection in Lodz with the meteorological conditions prevailing at this time. The analysis covers data from the years 2014-2017.

21. PHOTOCOPY OF PHOTOGRAPH. view north of Tropic Chamber, ca. ...

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

21. PHOTOCOPY OF PHOTOGRAPH. view north of Tropic Chamber, ca. 1955. (Source: NRDEC). - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

7. Detail view west of Arctic Chamber wind tunnel shell ...

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

7. Detail view west of Arctic Chamber wind tunnel shell (typical) in east elevation. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

23. PHOTOCOPY OF PHOTOGRAPH. View west of Tropic Chamber refrigeration ...

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

23. PHOTOCOPY OF PHOTOGRAPH. View west of Tropic Chamber refrigeration equipment, ca. 1955. (Source: NRDEC). - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

16. View northwest of Arctic Chamber Worthington centrifugal compressor and ...

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

16. View northwest of Arctic Chamber Worthington centrifugal compressor and control panel, in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

18. View north of Tropic Chamber Worthington centrifugal compressor and ...

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

18. View north of Tropic Chamber Worthington centrifugal compressor and control panel, in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

Fire environmental test chamber: its design and development

Treesearch

Clifford J. Auvil

1973-01-01

The Fire Environmental Test Chamber at the Forest Fire Laboratory, Riverside, California, can duplicate under controlled conditions the key factors that affect the flammability of wildland fuels. Within certain limits, it can produce air flow, solar radiation, temperatures, and relative humidity. First developed in 1962, the test chamber has since then undergoneseveral...

Early-Life Persistent Vitamin D Deficiency Alters Cardiopulmonary Responses to Particulate Matter-Enhanced Atmospheric Smog in Adult Mice

EPA Science Inventory

This study demonstrates that early-life persistent vitamin D deficiency alters the cardiopulmonary response to smog in mice and may increase risk of adverse effects. Early life nutritional deficiencies can lead to increased cardiovascular susceptibility to environme...

SU-E-T-677: Reproducibility of Production of Ionization Chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kukolowicz, P; Bulski, W; Ulkowski, P

Purpose: To compare the reproducibility of the production of several cylindrical and plane-parallel chambers popular in Poland in terms of a calibration coefficient. Methods: The investigation was performed for PTW30013 (20 chambers), 30001 (10 chambers), FC65-G (17 chambers) cylindrical chambers and for PPC05 (14 chambers), Roos 34001 (8 chambers) plane parallel chambers. The calibration factors were measured at the same accredited secondary standard laboratory in terms of a dose to water. All the measurements were carried out at the same laboratory, by the same staff, in accordance with the same IAEA recommendations. All the chambers were calibrated in the Co60more » beam. Reproducibility was described in terms of the mean value, its standard deviation and the ratio of the maximum and minimum value of calibration factors for each set of chambers separately. The combined uncertainty budged (1SD) calculated according to the IAEA-TECDOC-1585 of the calibration factor was of 0.25%. Results: The calibration coefficients for PTW30013, 30001, and FC65-G chambers were 5.36±0.03, 5.28±0.06, 4.79±0.015 nC/Gy respectively and for PPC05, and Roos chambers were 59±2, 8.3±0.1 nC/Gy respectively. The maximum/minimum ratio of calibration factors for PTW30013, 30001, FC65-G, and for PPC05, Roos chambers were 1.03, 1.03, 1.01, 1.14 and 1.03 respectively. Conclusion: The production of all ion chambers was very reproducible except the Markus type PPC05 for which the ratio of maximum/minimum calibration coefficients of 1.14 was obtained.« less

POGO-FAN: Remarkable Empirical Indicators for the Local Chemical Production of Smog- Ozone and NOx-Sensitivity of Air Parcels

NASA Astrophysics Data System (ADS)

Chatfield, R. B.; Browell, E. V.; Brune, W. H.; Crawford, J. H.; Esswein, R.; Fried, A.; Olson, J. R.; Shetter, R. E.; Singh, H. B.

2006-12-01

We propose and evaluate two related and surprisingly simple empirical estimators for the local chemical production term for photochemical ozone; each uses two moderate-technology chemical measurements and a measurement of ultraviolet light. We nickname the techniques POGO-FAN: Production of Ozone by Gauging Oxidation: Formaldehyde and NO. (1) A non-linear function of a single three-factor index-variable, j (HCHO=>rads) [HCHO] [NO] seems to provide a good estimator of the largest single term in the production of smog ozone, the HOO+NO term, over a very wide range of situations. (2) By considering empirical contour plots summarizing isopleths of HOO+NO using j (HCHO=>rads) [HCHO] and [NO] separately as coordinates, we provide a slightly more complex 2-d indicator of smog ozone production that additionally allows an estimate of the NOx-sensitivity or NOx-saturation (i.e., VOC-sensitivity) of sampled air parcels. ~85 to >90 % of the variance is explained. The correspondence to "EKMA" contour plots, estimating afternoon ozone based on morningtime organics and NOx mixes, is not coincidental. We utilize a broad set of urban plume, regionally polluted and cleaner NASA DC-8 PBL samples from the Intercontinental Transport Experiment-North America (INTEX-NA), in which each of the variables was measured, to help establish our relationship. The estimator is described in terms both both of asymptotic smog photochemistry theory; primarily this suggests appropriate statistical approaches which can capture some of the complex interrelations of lower-tropospheric smog mix through correlation of reactive mixture components. HCHO is not only an important source of HOO radicals, but it more important serves as a "gauge" of all photochemical processing of volatile organic compounds. It probably captures information related to coincident VOC sources of various compounds and parallels in photochemical processing. Constrained modeling of observed atmospheric concentrations suggests that

Evaluation of a disposable plastic Neubauer counting chamber for semen analysis.

PubMed

Kirkman-Brown, Jackson; Björndahl, Lars

2009-02-01

To evaluate whether disposable plastic counting chambers effectively could replace nondisposable, time-consuming, and potentially dangerous glass hemocytometers. Evaluation of equipment in modern laboratory andrology. Comparison of results obtained with plastic chambers with results obtained with "gold-standard" glass hemocytometer counts. Diagnostic laboratory for andrology. Twenty-one patients undergoing investigation for infertility problems. No interventions with patients; sperm in diluted semen samples were used when patients had allowed the use for research and training. Sperm concentration, difference from results obtained with standard equipment. In the first three experimental series, with use of standard routine phase-contrast microscopy, significantly lower count results were obtained consistently from the plastic chambers than from standard chambers. In the fourth series, with use of specialized equipment, equivalent results were obtained but with a considerably greater time commitment because of difficulties in distinguishing sperm adjacent to the gridlines in the plastic chambers. The plastic disposable chamber type was not suitable for routine semen analysis because results are variable depending on the microscope used, and increased time is necessary to do the assessment accurately.

Effects of seasonal smog on asthma and COPD exacerbations requiring emergency visits in Chiang Mai, Thailand.

PubMed

Pothirat, Chaicharn; Tosukhowong, Apiwat; Chaiwong, Warawut; Liwsrisakun, Chalerm; Inchai, Juthamas

2016-12-01

Seasonal smog produces particulate matters that are less than 10 microns in diameter (PM₁₀), which are known to have several impacts on the respiratory system. This study was to determine the association of an increased PM10 level due to seasonal smog in Chiang Mai and emergency visits for asthma and chronic obstructive pulmonary disease (COPD) exacerbations. A retrospective cross-sectional study was conducted between the months of January and March from 2006 until 2009. The association of an increased PM₁₀ level and the daily number of asthma and COPD exacerbations were analyzed using a generalized linear model; a Poisson regression model was fit to the number of daily emergency visits using predictor variables: lags of PM10, day of the week, and time. There were a total of 917 emergency visits for acute exacerbations of asthma and COPD, with a median of 2 visits per day (range 0-10). The median PM₁₀ level during the same interval was 64.5 microgram per cubic meter (μg/m3) (16-304). For every 10 μg/m3 rise in PM10 concentration, there was a lag time of 6 days for asthma exacerbations [Adjusted relative risk (RR)=1.020; 95% confident interval (CI), 1.001-1.040; (p=0.014)], 7 days for COPD exacerbations [RR=1.030; 95%CI, 1.010-1.050 (p=0.024)] and 7 days for all exacerbations [RR=1.030 95%CI, 1.010-1.040 (p<0.001)]. This study confirms the effect of increasing PM₁₀ concentrations from seasonal smog on asthma and COPD exacerbations. However, there was an approximately 1 week lag time between the elevated PM₁₀ levels and time to emergency visits due to disease exacerbation.

Constraining the Volatility Distributions and Possible Diffusion Limitations of Secondary Organic Aerosols Using Laboratory Dilution Experiments

NASA Astrophysics Data System (ADS)

Ye, Q.; Robinson, E. S.; Mahfouz, N.; Sullivan, R. C.; Donahue, N. M.

2016-12-01

Secondary organic aerosols (SOA) dominate the mass of fine particles in the atmosphere. Their formation involves both oxidation of volatile organics from various sources that produce products with uncertain volatilities, and diffusion of these products into the condensed phase. Therefore, constraining volatility distribution and diffusion timescales of the constituents in SOA are important in predicting size, concentration and composition of SOA, as well as how these properties of SOA evolve in the atmosphere. In this work, we demonstrate how carefully designed laboratory isothermal dilution experiments in smog chambers can shed light into the volatility distribution and any diffusion barriers of common types of SOA over time scales relevant to atmospheric transport and diurnal cycling. We choose SOA made from mono-terpenes (alpha-pinene and limonene) and toluene to represent biogenic and anthropogenic SOA. We look into how moisture content can alter any evaporation behaviors of SOA by varying relative humidity during SOA generation and during dilution process. This provides insight into whether diffusion in the condensed phase is rate limiting in reaching gas/particle equilibrium of semi-volatile organic compounds. Our preliminary results show that SOA from alpha-pinene evaporates continuously over several hours of experiments, and there is no substantial discernible differences over wide ranges of the chamber humidity. SOA from toluene oxidation shows slower evaporation. We fit these experimental data using absorptive partitioning theory and a particle dynamic model to obtain volatility distributions and to predict particle size evolution. This in the end will help us to improve representation of SOA in large scale chemical transport models.

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.

Potential oxidative stress in the bodies of electric arc welding operators: effect of photochemical smog.

PubMed

Zhu, You-Gen; Zhou, Jun-Fu; Shan, Wei-Ying; Zhou, Pei-Su; Tong, Gui-Zhong

2004-12-01

To investigate whether photochemical smog emitted during the process of electric arc welding might cause oxidative stress and potential oxidative damage in the bodies of welding operators. Seventy electric arc welding operators (WOs) and 70 healthy volunteers (HVs) were enrolled in a randomized controlled study design, in which the levels of vitamin C (VC) and vitamin E (VE) in plasma as well as the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and the level of lipoperoxide (LPO) in erythrocytes were determined by spectrophotometry. Compared with the average values of the above experimental parameters in the HVs group, the average values of VC and VE in plasma as well as those of SOD, CAT and GPX in erythrocytes in the WOs group were significantly decreased (P < 0.005-0.0001), while the average value of LPO in erythrocytes in the WOs group was significantly increased (P < 0.0001). The findings from the partial correlation analysis on the controlling of age suggested that with a prolonged duration of exposure to photochemical smog the values of VC, VE, SOD, and GPX, except for CAT, in the WOs were decreased gradually (P < 0.05-0.005), the value of LPO in the WOs was increased gradually (P < 0.001), and that with the ozone dose increased in the air in each worksite VC, VE, SOD, CAT and GPX decreased (P < 0.005-0.001), but LPO increased (P < 0.001). The findings from the reliability analysis for the VC, VE, SOD, CAT, GPX, and LPO values which were used to reflect oxidative stress and potential oxidative damage in the WOs showed that the reliability coefficients' alpha (6 items) was 0.8021, P < 0.0001, and that the standardized item alpha was 0.9577, P < 0.0001. Findings in the present study suggest that there exists an oxidative stress induced by long-term exposure to photochemical smog in the bodies of WOs, thereby causing potential oxidative and lipoperoxidative damages in their bodies.

Sealed Plant-Growth Chamber For Clinostat

NASA Technical Reports Server (NTRS)

Brown, Christopher S.; Dreschel, Thomas W.

1993-01-01

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

Particle formation above natural and simulated salt lakes

NASA Astrophysics Data System (ADS)

Kamilli, Katharina; Ofner, Johannes; Sattler, Tobias; Krause, Torsten; Zetzsch, Cornelius; Held, Andreas

2013-04-01

Western Australia was originally covered by natural eucalyptus forests, but land-use has changed considerably after large scale deforestation from 1950 to 1970. Thus, the ground-water level rose and brought dissolved salts and minerals to the surface. Nowadays, Western Australia is known for a great plenty of salt lakes with pH levels reaching from 2.5 to 7.1. The land is mainly used for wheat farming and livestock and becomes drier due to the lack of rain periods. One possible reason could be the formation of ultrafine particles from salt lakes, which increases the number of cloud condensation nuclei and thus potentially suppresses precipitation. Several field campaigns have been conducted between 2006 and 2011 with car-based and airborne measurements, where new particle formation has been observed and has been related to the Western Australian salt lakes (Junkermann et al., 2009). To identify particle formation directly above the salt lakes, a 1.5 m³ Teflon chamber was set up above several lakes in 2012. Inside the chamber, photochemistry may take place whereas mixing through wind or advection of already existing particles is prevented. Salt lakes with a low pH level lead to strongly increased aerosol formation. As salt lakes have been identified as a source for reactive halogen species (RHS; Buxmann et al., 2012) and RHS seem to interact with precursors of secondary organic aerosol (SOA), they could be producers of halogen induced secondary organic aerosol (XOA) (Ofner et al., 2012). As reference experiments, laboratory based aerosol smog-chamber runs were performed to examine XOA formation under atmospheric conditions using simulated sunlight and the chemical composition of a chosen salt lake. After adding α-pinene to the simulated salt lake, a strong nucleation event began in the absence of ozone comparable to the observed events in Western Australia. First results from the laboratory based aerosol smog-chamber experiments indicate a halogen-induced aerosol

The Other Shoe: An Early Operant Conditioning Chamber for Pigeons.

PubMed

Sakagami, Takayuki; Lattal, Kennon A

2016-05-01

We describe an early operant conditioning chamber fabricated by Harvard University instrument maker Ralph Gerbrands and shipped to Japan in 1952 in response to a request of Professor B. F. Skinner by Japanese psychologists. It is a rare example, perhaps the earliest still physically existing, of such a chamber for use with pigeons. Although the overall structure and many of the components are similar to contemporary pigeon chambers, several differences are noted and contrasted to evolutionary changes in this most important laboratory tool in the experimental analysis of behavior. The chamber also is testimony to the early internationalization of behavior analysis.

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

A watertight acrylic-free titanium recording chamber for electrophysiology in behaving monkeys

PubMed Central

Economides, John R.; Jocson, Cristina M.; Parker, John M.; Horton, Jonathan C.

2011-01-01

Neurophysiological recording in alert monkeys requires the creation of a permanent aperture in the skull for repeated insertion of microelectrodes. Most laboratories use polymethyl methacrylate to attach a recording chamber over the skull opening. Here, we describe a titanium chamber that fastens to the skull with screws, using no polymethyl methacrylate. The gap between the base of the chamber and the skull is filled with hydroxyapatite, forming a watertight gasket. As the chamber base osseointegates with the skull, the hydroxyapatite is replaced with bone. Rather than having a finite lifetime, the recording chamber becomes more firmly anchored the longer it is in place. It has a small footprint, low profile, and needs little maintenance to control infection. Toilette consists of occasional application of betadine to clean the scalp margin, followed by application of neomycin, polymyxin, and bacitracin ointment. Antibiotic is also placed inside the chamber to suppress bacterial proliferation. Thickening of the dura within the chamber can be prevented by regular application of mitocycin C and/or bevacizumab, an antibody against vascular endothelial growth factor. By conducting an e-mail survey, this protocol for chamber maintenance was compared with procedures used in 37 other vision research laboratories. Refinement of appliances and techniques used for recordings in awake monkeys promises to increase the pace of scientific discovery and to benefit animal welfare. PMID:21676928

Cattle waste tops cars as source of Southern California smog

NASA Astrophysics Data System (ADS)

Schultz, Colin

2012-06-01

A new study shows that cows, not cars, are the more substantial source of ammonia that leads to ammonium nitrate in California's South Coast Air Basin, the smoggiest place in the United States. Within the region, which consists of the area surrounding and downwind of Los Angeles, a large proportion of the fine-grained particulate matter that makes up smog is formed from ammonium nitrate. Nowak et al. found two main sources of ammonium nitrate: small gas-powered vehicles and dairy farms. Catalytic converters designed to stem the emissions of carbon monoxide, nitrogen oxides, and hydrocarbons from the region's 9.9 million vehicles can produce gaseous ammonia as an unwanted by-product. Bacteria decomposing organic wastes from the region's 298,000 dairy cattle, on the other hand, also account for a sizable source of ammonia emissions.

Evaluation of carbon dioxide dissipation within a euthanasia chamber.

PubMed

Djoufack-Momo, Shelly M; Amparan, Ashlee A; Grunden, Beverly; Boivin, Gregory P-

2014-07-01

CO₂ euthanasia is used widely for small laboratory animals, such as rodents. A common necessity in many animal research facilities is to euthanize mice in sequential batches. We assessed the effects of several variables on the time it took for CO₂ to dissipate within a chamber. Using standard euthanasia time, changes in flow rate were compared between a slow 15% fill rate for 7 min, and a slow 15% followed by a rapid 50% filling for a total of 5 min. Additional variables assessed included the effects of opening the lid after the completion of chamber filling, turning the chamber over after completion of filling, and the use and removal of a cage from within the chamber. For all trials, CO₂ levels in the chambers peaked between 50% and 80%. After the gas was turned off, the concentration of CO₂ dropped to below 10% COv within 2 min, except when the lid was left on the chamber, where concentration levels remained above 10% after 20 min. CO₂ dissipation was significantly faster when the chamber was turned upside down after filling. Significant interaction effects occurred among the factors of cage presence within the chamber, flow rate, and chamber position. Only leaving the lid on the chamber had any practical implication for delaying CO₂ dissipation. We recommend that users allow 2 min for CO₂ to clear from the chamber before subsequent euthanasia procedures, unless the chamber is manipulated to increase the dissipation rate.

Chamber for mechanical testing in H2 with observation by neutron scattering

NASA Astrophysics Data System (ADS)

Connolly, Matthew; Bradley, Peter; Slifka, Andrew; Drexler, Elizabeth

2017-06-01

A gas-pressure chamber has been designed, constructed, and tested at a moderate pressure (3.4 MPa, 500 psi) and has the capability of mechanical loading of steel specimens for neutron scattering measurements. The chamber will allow a variety of in situ neutron scattering measurements: in particular, diffraction, quasielastic scattering, inelastic scattering, and imaging. The chamber is compatible with load frames available at the user facilities at the NIST Center for Neutron Research and Oak Ridge National Laboratory Spallation Neutron Source. A demonstration of neutron Bragg edge imaging using the chamber is presented.

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.

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

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.

Initial Back-to-Back Fission Chamber Testing in ATRC

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 providemore » 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.« less

Evaluation of Carbon Dioxide Dissipation within a Euthanasia Chamber

PubMed Central

Djoufack-Momo, Shelly M; Amparan, Ashlee A; Grunden, Beverly; Boivin, Gregory P

2014-01-01

CO2 euthanasia is used widely for small laboratory animals, such as rodents. A common necessity in many animal research facilities is to euthanize mice in sequential batches. We assessed the effects of several variables on the time it took for CO2 to dissipate within a chamber. Using standard euthanasia time, changes in flow rate were compared between a slow 15% fill rate for 7 min, and a slow 15% followed by a rapid 50% filling for a total of 5 min. Additional variables assessed included the effects of opening the lid after the completion of chamber filling, turning the chamber over after completion of filling, and the use and removal of a cage from within the chamber. For all trials, CO2 levels in the chambers peaked between 50% and 80%. After the gas was turned off, the concentration of CO2 dropped to below 10% CO2 within 2 min, except when the lid was left on the chamber, where concentration levels remained above 10% after 20 min. CO2 dissipation was significantly faster when the chamber was turned upside down after filling. Significant interaction effects occurred among the factors of cage presence within the chamber, flow rate, and chamber position. Only leaving the lid on the chamber had any practical implication for delaying CO2 dissipation. We recommend that users allow 2 min for CO2 to clear from the chamber before subsequent euthanasia procedures, unless the chamber is manipulated to increase the dissipation rate. PMID:25199098

The response of ionization chambers to relativistic heavy nuclei

NASA Technical Reports Server (NTRS)

Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Fixsen, D. J.; Garrard, T. L.; Grimm, G.; Israel, M. H.; Klarmann, J.

1985-01-01

The LBL Bevalac for the Heavy Nuclei Experiment on HEAO-3, compared the response of a set of laboratory ionization chambers to beams of 26Fe, 36Kr, 54Xe, 67 Ho, and 79Au nuclei at maximum energies ranging from 1666 MeV/amu for Fe to 1049 MeV/amu for Au. The response of these chambers shows a significant deviation from the expected energy dependence, but only a slight deviation from Z sq scaling.

Indirect check of the stability of the reference ion chamber used for accelerator output calibration

NASA Astrophysics Data System (ADS)

Kang, Sei-Kwon; Yoon, Jai-Woong; Park, Soah; Hwang, Taejin; Cheong, Kwang-Ho; Han, Tae Jin; Kim, Haeyoung; Lee, Me-Yeon; Kim, Kyoung Ju; Bae, Hoonsik

2014-11-01

A linear accelerator's output is periodically checked by using a reference ion chamber which is also periodically calibrated at the accredited standard dosimetry laboratories. We suggest a simple procedure for checking the chamber's stability between calibrations by comparison with another ion chamber. To identify the long-term stability of chambers, we collected and assessed the dose-to-water conversion factors provided by standard laboratories for three chambers during a period of four years. To develop the chamber constancy check program, we used one Farmer-type reference ion chamber FC65-G, two ion chambers (CC13a and CC13b) and one CC01 ion chamber (IBA). Under the accelerator, each chamber was placed inside the solid phantom and irradiated; the experimental configurations were identical. To check the variation in charge collection of the reference chamber, we monitored the ratios of the FC65-G values over each chamber reading. Based on the error propagation of the two chamber ratios, we estimated the uncertainty of the output calibration from the chamber variation. The calibration factors provided for the three chambers showed 0.04 ˜ 0.12% standard deviations during four years. For procedure development, the reading ratios of FC65-G over CCxx showed very good stability; the ratios of FC65-G over CC13a, CC13b and CC01 varied less than 0.059, 0.087 and 0.248%, respectively, over five measurements. By ascribing possible uncertainties of the ratio to the reference chamber alone, we could conservatively check the stability of the reference chamber for treatment safety. An extension of the chamber calibration period was also evaluated. In conclusion, we designed a stability check procedure for the reference chamber based on a reading ratio of two chambers. This could help the user assess the chamber stability between periodic chamber calibration, and the associated patient treatment could be carried out with enhanced safety.

Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multilayer model ADCHAM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roldin, P.; Eriksson, A. C.; Nordin, E. Z.

2014-08-11

We have developed the novel Aerosol Dynamics, gas- and particle- phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas phase Master Chemical Mechanism version 3.2, an aerosol dynamics and particle phase chemistry module (which considers acid catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study: 1) the mass transfer limited uptake of ammonia (NH3)more » and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), 2) the slow and almost particle size independent evaporation of α-pinene secondary organic aerosol (SOA) particles, and 3) the influence of chamber wall effects on the observed SOA formation in smog chambers.« less

Voss at ADVASC Growth Chamber in Destiny module

NASA Image and Video Library

2001-05-22

ISS002-E-6300 (22 May 2001) --- James S. Voss, Expedition Two flight engineer, works with the Advanced Astro Culture (ADVASC) Condensate Fluid Syringe at the ADVASC Growth Chamber in the U.S. Laboratory. The image was taken with a digital still camera.

The response of ionization chambers to relativistic heavy nuclei

NASA Technical Reports Server (NTRS)

Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Fixsen, D. J.; Garrard, T. L.; Grimm, G.; Israel, M. H.; Klarmann, J.

1985-01-01

As part of a recent calibration at the LBL Bevalac for the Heavy Nuclei Experiment on HEAO-3, the response of a set of laboratory ionization chambers were compared to beams of 26Fe, 36 Kr, 54Xe, 67 Ho, and 79 Au nuclei at maximum energies ranging from 1666 MeV/amu for Fe to 1049 MeV/amu for Au. The response of these chambers shows a significant deviation from the expected energy dependence, but only a slight deviation from Z squared scaling.

Electric Propulsion Laboratory Vacuum Chamber

NASA Image and Video Library

1964-06-21

Engineer Paul Reader and his colleagues take environmental measurements during testing of a 20-inch diameter ion engine in a vacuum tank at the Electric Propulsion Laboratory (EPL). Researchers at the Lewis Research Center were investigating the use of a permanent-magnet circuit to create the magnetic field required power electron bombardment ion engines. Typical ion engines use a solenoid coil to create this magnetic field. It was thought that the substitution of a permanent magnet would create a comparable magnetic field with a lower weight. Testing of the magnet system in the EPL vacuum tanks revealed no significant operational problems. Reader found the weight of the two systems was similar, but that the thruster’s efficiency increased with the magnet. The EPL contained a series of large vacuum tanks that could be used to simulate conditions in space. Large vacuum pumps reduced the internal air pressure, and a refrigeration system created the cryogenic temperatures found in space.

Simulating Titan-Like Smog

NASA Image and Video Library

2013-04-03

In a laboratory experiment at NASA Jet Propulsion Laboratory, Pasadena, Calif., scientists simulate the atmosphere of Saturn moon Titan. In this picture, molecules of dicyanoacetylene are seen on a special film on a sapphire window.

Chamber-core structures for fairing acoustic mitigation

NASA Astrophysics Data System (ADS)

Ardelean, Emil; Williams, Andrew; Korshin, Nicholas; Henderson, Kyle; Lane, Steven; Richard, Robert

2005-05-01

Extreme noise and vibration levels at lift-off and during ascent can damage sensitive payload components. Recently, the Air Force Research Laboratory, Space Vehicles Directorate has investigated a composite structure fabrication approach, called chamber-core, for building payload fairings. Chamber-core offers a strong, lightweight structure with inherent noise attenuation characteristics. It uses one-inch square axial tubes that are sandwiched between inner and outer face-sheets to form a cylindrical fairing structure. These hollow tubes can be used as acoustic dampers to attenuate the amplitude response of low frequency acoustic resonances within the fairing"s volume. A cylindrical, graphite-epoxy chamber-core structure was built to study noise transmission characteristics and to quantify the achievable performance improvement. The cylinder was tested in a semi-reverberant acoustics laboratory using bandlimited random noise at sound pressure levels up to 110 dB. The performance was measured using external and internal microphones. The noise reduction was computed as the ratio of the spatially averaged external response to the spatially averaged interior response. The noise reduction provided by the chamber-core cylinder was measured over three bandwidths, 20 Hz to 500 Hz, 20 Hz to 2000 Hz, and 20 Hz to 5000 Hz. For the bare cylinder with no acoustic resonators, the structure provided approximately 13 dB of attenuation over the 20 Hz to 500 Hz bandwidth. With the axial tubes acting as acoustic resonators at various frequencies over the bandwidth, the noise reduction provided by the cylinder increased to 18.2 dB, an overall increase of 4.8 dB over the bandwidth. Narrow-band reductions greater than 10 dB were observed at specific low frequency acoustic resonances. This was accomplished with virtually no added mass to the composite cylinder.

Accuracy of semen counting chambers as determined by the use of latex beads.

PubMed

Seaman, E K; Goluboff, E; BarChama, N; Fisch, H

1996-10-01

To assess the accuracy of the Hemacytometer (Hausser Scientific, Horsham, PA), Makler (Sefi-Medical Instrument, Haifa, Israel), Cell-VU (Millennium Sciences Inc., New York, NY), and Micro-Cell chambers (Conception Technologies, San Diego, CA) counting chambers. A solution containing a known concentration of latex beads was used as the standard to perform counts on the four different counting chambers. Bead counts for the four different chambers were compared with the bead counts of the standard solution. Variability within chambers also was determined. Mean bead concentrations for both the Cell-VU and Micro-Cell chambers were consistently similar to the bead concentration of the standard solution. Both the hemacytometer and the Makler chambers overestimated the actual bead concentration of the standard solution by as much as 50% and revealed significant interchamber variability. Our data revealed marked differences in the accuracy and reliability of the different counting chambers tested and emphasized the need for standardization and quality control of laboratory procedures.

SOURCES OF ORGANIC AEROSOL: SEMIVOLATILE EMISSIONS AND PHOTOCHEMICAL AGING

EPA Science Inventory

The proposed research integrates emissions testing, smog chamber experiments, and regional chemical transport models (CTMs) to investigate the sources of organic aerosol in urban and regional environments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koukol, J.; Dugger, W.M. Jr.

The isolation and characterization of a cyanidin glucoside from leaves of dock plants (Rumerx crispus L.) after exposure to smog are described. Experiments in which plants were exposed only to ozone, a component of smog, also led to the appearance of the anthocyanin in the leaves of plants. Identification of the anthocyanin was undertaken as the first step in studying the stimulatory effect of ozone on anthocyanin biosynthesis. The ozone fumigations were carried out in special chambers.

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.

Chamber for Aerosol Deposition of Bioparticles

NASA Technical Reports Server (NTRS)

Kern, Roger; Kirschner, Larry

2008-01-01

Laboratory apparatus is depicted that is a chamber for aerosol deposition of bioparticles on surfaces of test coupons. It is designed for primary use in inoculating both flat and three-dimensional objects with approximately reproducible, uniform dispersions of bacterial spores of the genus Bacillus so that the objects could be used as standards for removal of the spores by quantitative surface sampling and/or cleaning processes. The apparatus is also designed for deposition of particles other than bacterial spores, including fungal spores, viruses, bacteriophages, and standard micron-sized beads. The novelty of the apparatus lies in the combination of a controllable nebulization system with a settling chamber large enough to contain a significant number of test coupons. Several companies market other nebulizer systems, but none are known to include chambers for deposition of bioparticles to mimic the natural fallout of bioparticles. The nebulization system is an expanded and improved version of commercially available aerosol generators that include nebulizers and drying columns. In comparison with a typical commercial aerosol generator, this system includes additional, higher-resolution flowmeters and an additional pressure regulator. Also, unlike a typical commercial aerosol generator, it includes stopcocks for separately controlling flows of gases to the nebulizer and drying column. To maximize the degree of uniformity of dispersion of bioaerosol, the chamber is shaped as an axisymmetrical cylinder and the aerosol generator is positioned centrally within the chamber and aimed upward like a fountain. In order to minimize electric charge associated with the aerosol particles, the drying column is made of aluminum, the drying column is in direct contact with an aluminum base plate, and three equally spaced Po-210 antistatic strips are located at the exit end of the drying column. The sides and top of the chamber are made of an acrylic polymer; to prevent

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

NASA Astrophysics Data System (ADS)

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

2009-04-01

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

A closed unventilated chamber for the measurement of transepidermal water loss.

PubMed

Nuutinen, Jouni; Alanen, Esko; Autio, Pekka; Lahtinen, Marjo-Riitta; Harvima, Ilkka; Lahtinen, Tapani

2003-05-01

Open chamber systems for measuring transepidermal water loss (TEWL) have limitations related to ambient and body-induced airflows near the probe, probe size, measurement sites and angles, and measurement range. The aim of the present investigation was to develop a closed chamber system for the TEWL measurement without significant blocking of normal evaporation through the skin. Additionally, in order to use the evaporimeter to measure evaporation rates through other biological and non-biological specimens and in the field applications, a small portable, battery-operated device was a design criteria. A closed unventilated chamber (inner volume 2.0 cm(3) was constructed. For the skin measurement, the chamber with one side open (open surface area 1.0 cm(2) is placed on the skin. The skin application time was investigated at low and high evaporation rates in order to assess the blocking effect of the chamber on normal evaporation. From the rising linear part of the relative humidity (RH) in the chamber the slope was registered. The slope was calibrated into a TEWL value by evaporating water at different temperatures and measuring the water loss of heated samples with a laboratory scale. The closed chamber evaporation technique was compared with a conventional evaporimeter based on an open chamber method (DermaLab), Cortex Technology, Hadsund, Denmark). The reproducibility of the closed chamber method was measured with the water samples and with volar forearm and palm of the hand in 10 healthy volunteers. The skin application time varied between 7 and 9 s and the linear slope region between 3 and 5 s at the evaporation rates of 3-220 g/m(2) h. A correlation coefficient between the TEWL value from the closed chamber measurements and the readings of the laboratory scale was 0.99 (P < 0.001). The reproducibility of the evaporation measurements with the water samples was 4.0% at the evaporation rate of 40 g/m(2) h. A correlation coefficient of the TEWL values between the

Photochemical smog effects in mixed conifer forests along a natural gradient of ozone and nitrogen deposition in the San Bernardino Mountains

Treesearch

Michael Arbaugh; Andrzej Bytnerowicz; Nancy Grulke; Mark Fenn; Mark Poth; Patrick Temple; Paul Miller

2003-01-01

Toxic effects of photochemical smog on ponderosa and Jeffrey pines in the San Bernardino Mountains were discovered in the 1950s. It was revealed that ozone is the main cause of foliar injury manifested as chlorotic mottle and premature needle senescence. Various morphological, physiological and biochemical alterations in the affected plants have been reported over a...

Advanced Small Rocket Chambers. Basic Program and Option 2: Fundamental Processes and Material Evaluation

NASA Technical Reports Server (NTRS)

Jassowski, Donald M.

1993-01-01

Propellants, chamber materials, and processes for fabrication of small high performance radiation cooled liquid rocket engines were evaluated to determine candidates for eventual demonstration in flight-type thrusters. Both storable and cryogenic propellant systems were considered. The storable propellant systems chosen for further study were nitrogen tetroxide oxidizer with either hydrazine or monomethylhydrazine as fuel. The cryogenic propellants chosen were oxygen with either hydrogen or methane as fuel. Chamber material candidates were chemical vapor deposition (CVD) rhenium protected from oxidation by CVD iridium for the chamber hot section, and film cooled wrought platinum-rhodium or regeneratively cooled stainless steel for the front end section exposed to partially reacted propellants. Laser diagnostics of the combustion products near the hot chamber surface and measurements at the surface layer were performed in a collaborative program at Sandia National Laboratories, Livermore, CA. The Material Sample Test Apparatus, a laboratory system to simulate the combustion environment in terms of gas and material temperature, composition, and pressure up to 6 Atm, was developed for these studies. Rocket engine simulator studies were conducted to evaluate the materials under simulated combustor flow conditions, in the diagnostic test chamber. These tests used the exhaust species measurement system, a device developed to monitor optically species composition and concentration in the chamber and exhaust by emission and absorption measurements.

Conceptual design considerations and neutronics of lithium fall laser fusion target chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, W.R.; Thomson, W.B.

1978-05-31

Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage.

STUDY USING A THREE-DIMENSIONAL PHOTOCHEMICAL SMOG FORMATION MODEL UNDER CONDITIONS OF COMPLEX FLOW: APPLICATION OF THE URBAN AIRSHED MODEL TO THE TOKYO METROPOLITAN AREA

EPA Science Inventory

The purpose of this study is to evaluate the Urban Airshed Model (UAM), a three-dimensional photochemical urban air quality simulation model, using field observations from the Tokyo Metropolitan Area. mphasis was placed on the photochemical smog formation mechanism under stagnant...

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.

Estimation of absorbed dose in clinical radiotherapy linear accelerator beams: Effect of ion chamber calibration and long-term stability

PubMed Central

Ravichandran, Ramamoorthy; Binukumar, Johnson Pichy; Davis, Cheriyathmanjiyil Antony

2013-01-01

The measured dose in water at reference point in phantom is a primary parameter for planning the treatment monitor units (MU); both in conventional and intensity modulated/image guided treatments. Traceability of dose accuracy therefore still depends mainly on the calibration factor of the ion chamber/dosimeter provided by the accredited Secondary Standard Dosimetry Laboratories (SSDLs), under International Atomic Energy Agency (IAEA) network of laboratories. The data related to Nd,water calibrations, thermoluminescent dosimetry (TLD) postal dose validation, inter-comparison of different dosimeter/electrometers, and validity of Nd,water calibrations obtained from different calibration laboratories were analyzed to find out the extent of accuracy achievable. Nd,w factors in Gray/Coulomb calibrated at IBA, GmBH, Germany showed a mean variation of about 0.2% increase per year in three Farmer chambers, in three subsequent calibrations. Another ion chamber calibrated in different accredited laboratory (PTW, Germany) showed consistent Nd,w for 9 years period. The Strontium-90 beta check source response indicated long-term stability of the ion chambers within 1% for three chambers. Results of IAEA postal TL “dose intercomparison” for three photon beams, 6 MV (two) and 15 MV (one), agreed well within our reported doses, with mean deviation of 0.03% (SD 0.87%) (n = 9). All the chamber/electrometer calibrated by a single SSDL realized absorbed doses in water within 0.13% standard deviations. However, about 1-2% differences in absorbed dose estimates observed when dosimeters calibrated from different calibration laboratories are compared in solid phantoms. Our data therefore imply that the dosimetry level maintained for clinical use of linear accelerator photon beams are within recommended levels of accuracy, and uncertainties are within reported values. PMID:24672156

Chamber study of PCBemissions from caulking materials and light ballasts

EPA Science Inventory

The emissions of polychlorinated biphenyl (PCB) congeners from 13 caulk samples were tested in a micro-chamber system. Twelve samples were from PCB-contaminated buildings and one was prepared in the laboratory. Nineteen light ballasts collected from buildings that represent 13 di...

Technical note: Headspace analysis of explosive compounds using a novel sampling chamber.

PubMed

DeGreeff, Lauryn; Rogers, Duane A; Katilie, Christopher; Johnson, Kevin; Rose-Pehrsson, Susan

2015-03-01

The development of instruments and methods for explosive vapor detection is a continually evolving field of interest. A thorough understanding of the characteristic vapor signatures of explosive material is imperative for the development and testing of new and current detectors. In this research a headspace sampling chamber was designed to contain explosive materials for the controlled, reproducible sampling and characterization of vapors associated with these materials. In a detonation test, the chamber was shown to contain an explosion equivalent to three grams of trinitrotoluene (TNT) without damage to the chamber. The efficacy of the chamber in controlled headspace sampling was evaluated in laboratory tests with bulk explosive materials. Small quantities of TNT, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) were separately placed in the sampling chamber, and the headspace of each material was analyzed by gas chromatography/mass spectrometry (GC/MS) with online cryogenic trapping to yield characteristic vapor signatures for each explosive compound. Chamber sampling conditions, temperature and sampling time, were varied to demonstrate suitability for precise headspace analysis. Published by Elsevier Ireland Ltd.

Aging of plumes from emission sources based on chamber simulation

NASA Astrophysics Data System (ADS)

Wang, X.; Deng, W.; Fang, Z.; Bernard, F.; Zhang, Y.; Yu, J.; Mellouki, A.; George, C.

2017-12-01

Study on atmospheric aging of plumes from emission sources is essential to understand their contribution to both secondary and primary pollutants occurring in the ambient air. Here we directly introduced vehicle exhaust, biomass burning plume, industrial solvents and cooking plumes into a smog chamber with 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor housed in a temperature-controlled enclosure, for characterizing primarily emitted air pollutants and for investigating secondarily formed products during photo-oxidation. Moreover, we also initiated study on the formation of secondary aerosols when gasoline vehicle exhaust is mixed with typical coal combustion pollutant SO2 or typical agricultural-related pollutant NH3. Formation of secondary organic aerosols (SOA) from typical solvent toluene was also investigated in ambient air matrix in comparison with purified air matrix. Main findings include: 1) Except for exhaust from idling gasoline vehicles, traditional precursor volatile organic compounds could only explain a very small fraction of SOA formed from vehicle exhaust, biomass burning or cooking plumes, suggesting knowledge gap in SOA precursors; 2) There is the need to re-think vehicle emission standards with a combined primary and/or secondary contribution of vehicle exhaust to PM2.5 or other secondary pollutants such as ozone; 3) When mixed with SO2, the gasoline vehicle exhaust revealed an increase of SOA production factor by 60-200% and meanwhile SO2 oxidation rates increased about a factor of 2.7; when the aged gasoline vehicle exhaust were mixing with NH3, both particle number and mass concentrations were increasing explosively. These phenomenons implied the complex interaction during aging of co-existing source emissions. 4) For typical combination of "tolune+SO2+NOx", when compared to chamber simulation with purified air as matrix, both SOA formation and SO2 oxidation were greatly enhanced under ambient air matrix, and the enhancement

EML pulse ionization chamber systems for /sup 222/Rn measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisenne, I M; Keller, H W

1985-03-01

Radon measurements have been performed with pulse ionization chambers at the Environmental Measurements Laboratory (EML) for over 35 years. This report describes the evolution of radon measurement systems, with emphasis on the continuous quality control efforts at EML. 38 refs., 3 figs., 3 tabs.

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.

Optical Characterization Laboratory | Energy Systems Integration Facility |

Science.gov Websites

Laboratory offers the following capabilities. Solar Thermal Calibration The Optical Characterization collectors for solar thermal energy generation to enable the study of increasingly stable (less intermittent Characterization Laboratory's environmental characterization hub offers high-temperature/humidity thermal chambers

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

On The Development of One-way Nesting of Air-pollution Model Smog Into Numerical Weather Prediction Model Eta

NASA Astrophysics Data System (ADS)

Halenka, T.; Bednar, J.; Brechler, J.

The spatial distribution of air pollution on the regional scale (Bohemian region) is simulated by means of Charles University puff model SMOG. The results are used for the assessment of the concentration fields of ozone, nitrogen oxides and other ozone precursors. Current improved version of the model covers up to 16 groups of basic compounds and it is based on trajectory computation and puff interaction both by means of Gaussian diffusion mixing and chemical reactions of basic species. Gener- ally, the method used for trajectory computation is valuable mainly for episodes sim- ulation, nevertheless, climatological study can be solved as well by means of average wind rose. For the study being presented huge database of real emission sources was incorporated with all kind of sources included. Some problem with the background values of concentrations was removed. The model SMOG has been nested into the forecast model ETA to obtain appropriate meteorological data input. We can estimate air pollution characteristics both for episodes analysis and the prediction of future air quality conditions. Necessary prognostic variables from the numerical weather pre- diction model are taken for the region of the central Bohemia, where the original puff model was tested. We used mainly 850 hPa wind field for computation of prognos- tic trajectories, the influence of surface temperature as a parameter of photochemistry reactions as well as the effect of cloudness has been tested.

Passivation of micro-strip gas chambers with an interstitial germanium coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyamoto, J.; Knoll, G.F.; Amos, N.

1996-12-31

Micro-strip gas chambers (MSGCs) were constructed in the Solid-State Electronics Laboratory of the University of Michigan and their performance was studied. Many efforts have been made in the past to construct MSGCs that yield high absolute gas gain and stable gas gain. Introducing a thin germanium layer has been effective for passivation but difficulties associated with the poor adhesiveness of the thin layer have been a serious obstacle. This paper reports on a new method used to overcome these difficulties. Unlike the conventional coating method the thin germanium layer was successfully deposited between the strip lines. This technique requires amore » careful geometric alignment of a second photomask with the original micro-strip structure. The resulting detector performance was noteworthy and an absolute gas gain of 2 {center_dot} 10{sup 4} was easily achieved by the new chamber. The chamber`s gain instability was also reduced significantly compared with those without interstitial coating.« less

Implementation of Autonomous Control Technology for Plant Growth Chambers

NASA Technical Reports Server (NTRS)

Costello, Thomas A.; Sager, John C.; Krumins, Valdis; Wheeler, Raymond M.

2002-01-01

The Kennedy Space Center has significant infrastructure for research using controlled environment plant growth chambers. Such research supports development of bioregenerative life support technology for long-term space missions. Most of the existing chambers in Hangar L and Little L will be moved to the new Space Experiment Research and Processing Laboratory (SERPL) in the summer of 2003. The impending move has created an opportunity to update the control system technologies to allow for greater flexibility, less labor for set-up and maintenance, better diagnostics, better reliability and easier data retrieval. Part of these improvements can be realized using hardware which communicates through an ethernet connection to a central computer for supervisory control but can be operated independently of the computer during routine run-time. Both the hardware and software functionality of an envisioned system were tested on a prototype plant growth chamber (CEC-4) in Hangar L. Based upon these tests, recommendations for hardware and software selection and system design for implementation in SERPL are included.

Ion chamber absorbed dose calibration coefficients, N{sub D,w}, measured at ADCLs: Distribution analysis and stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muir, B. R., E-mail: Bryan.Muir@nrc-cnrc.gc.ca

2015-04-15

Purpose: To analyze absorbed dose calibration coefficients, N{sub D,w}, measured at accredited dosimetry calibration laboratories (ADCLs) for client ionization chambers to study (i) variability among N{sub D,w} coefficients for chambers of the same type calibrated at each ADCL to investigate ion chamber volume fluctuations and chamber manufacturing tolerances; (ii) equivalency of ion chamber calibration coefficients measured at different ADCLs by intercomparing N{sub D,w} coefficients for chambers of the same type; and (iii) the long-term stability of N{sub D,w} coefficients for different chamber types by investigating repeated chamber calibrations. Methods: Large samples of N{sub D,w} coefficients for several chamber types measuredmore » over the time period between 1998 and 2014 were obtained from the three ADCLs operating in the United States. These are analyzed using various graphical and numerical statistical tests for the four chamber types with the largest samples of calibration coefficients to investigate (i) and (ii) above. Ratios of calibration coefficients for the same chamber, typically obtained two years apart, are calculated to investigate (iii) above and chambers with standard deviations of old/new ratios less than 0.3% meet stability requirements for accurate reference dosimetry recommended in dosimetry protocols. Results: It is found that N{sub D,w} coefficients for a given chamber type compared among different ADCLs may arise from differing probability distributions potentially due to slight differences in calibration procedures and/or the transfer of the primary standard. However, average N{sub D,w} coefficients from different ADCLs for given chamber types are very close with percent differences generally less than 0.2% for Farmer-type chambers and are well within reported uncertainties. Conclusions: The close agreement among calibrations performed at different ADCLs reaffirms the Calibration Laboratory Accreditation Subcommittee process of

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

PubMed

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

2014-03-01

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

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.

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

Unspeciated organic emissions from combustion sources and their influence on the secondary organic aerosol budget in the United States

EPA Science Inventory

Secondary organic aerosol (SOA) formed from the atmospheric oxidation of nonmethane organic gases (NMOG) is a major contributor to atmospheric aerosol mass. Emissions and smog chamber experiments were performed to investigate SOA formation from gasoline vehicles, diesel vehicles,...

Effect of nitrous acid on lung function in asthmatics: a chamber study.

PubMed Central

Beckett, W S; Russi, M B; Haber, A D; Rivkin, R M; Sullivan, J R; Tameroglu, Z; Mohsenin, V; Leaderer, B P

1995-01-01

Nitrous acid, a component of photochemical smog and a common indoor air pollutant, may reach levels of 100 ppb where gas stoves and unvented portable kerosene heaters are used. Nitrous acid is a primary product of combustion and may also be a secondary product by reaction of nitrogen dioxide with water. Because the usual assays for nitrogen dioxide measure several oxides of nitrogen (including nitrous acid) together, previous studies of indoor nitrogen dioxide may have included exposure to and health effects of nitrous acid. To assess the respiratory effects of nitrous acid exposure alone, we carried out a double-blinded crossover chamber exposure study with 11 mildly asthmatic adult subjects. Each underwent 3-hr exposures to 650 ppb nitrous acid and to filtered room air with three 20-min periods of moderate cycle exercise. Symptoms, respiratory parameters during exercise, and spirometry after exercise were measured. A statistically significant decrease in forced vital capacity was seen on days when subjects were exposed to nitrous acid. This effect was most marked at 25 min and 85 min after exposure began. Aggregate respiratory and mucous membrane symptoms were also significantly higher with nitrous acid. We conclude that this concentration and duration of exposure to nitrous acid alters lung mechanics slightly, does not induce significant airflow obstruction, and produces mild irritant symptoms in asthmatics. Images Figure 1. PMID:7607138

Volatile Organic Compounds from Logwood Combustion: Emissions and Transformation under Dark and Photochemical Aging Conditions in a Smog Chamber.

PubMed

Hartikainen, Anni; Yli-Pirilä, Pasi; Tiitta, Petri; Leskinen, Ari; Kortelainen, Miika; Orasche, Jürgen; Schnelle-Kreis, Jürgen; Lehtinen, Kari E J; Zimmermann, Ralf; Jokiniemi, Jorma; Sippula, Olli

2018-04-17

Residential wood combustion (RWC) emits high amounts of volatile organic compounds (VOCs) into ambient air, leading to formation of secondary organic aerosol (SOA), and various health and climate effects. In this study, the emission factors of VOCs from a logwood-fired modern masonry heater were measured using a Proton-Transfer-Reactor Time-of-Flight Mass Spectrometer. Next, the VOCs were aged in a 29 m 3 Teflon chamber equipped with UV black lights, where dark and photochemical atmospheric conditions were simulated. The main constituents of the VOC emissions were carbonyls and aromatic compounds, which accounted for 50%-52% and 30%-46% of the detected VOC emission, respectively. Emissions were highly susceptible to different combustion conditions, which caused a 2.4-fold variation in emission factors. The overall VOC concentrations declined considerably during both dark and photochemical aging, with simultaneous increase in particulate organic aerosol mass. Especially furanoic and phenolic compounds decreased, and they are suggested to be the major precursors of RWC-originated SOA in all aging conditions. On the other hand, dark aging produced relatively high amounts of nitrogen-containing organic compounds in both gas and particulate phase, while photochemical aging increased especially the concentrations of certain gaseous carbonyls, particularly acid anhydrides.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Characterizing oxidative flow reactor SOA production and OH radical exposure from laboratory experiments of complex mixtures (engine exhaust) and simple precursors (monoterpenes)

NASA Astrophysics Data System (ADS)

Michael Link, M. L.; Friedman, B.; Ortega, J. V.; Son, J.; Kim, J.; Park, G.; Park, T.; Kim, K.; Lee, T.; Farmer, D.

2016-12-01

volatility of the aerosol, and compare observed SOA yields to other OFR and smog chamber SOA generation methods. Additionally, estimates of OH radical exposure in the OFR during different vehicle experiments of varying fuel type and speed were observed to vary as determined from a high-NOx and variable humidity calibration set.

Evaluation of Visibility Sensors at the Eglin Air Force Base Climatic Chamber

DOT National Transportation Integrated Search

1983-10-01

Three transmissometers and five forward-scatter meters were evaluated for measuring fog, haze, rain and snow in the large test chamber of the Eglin Air Force Base Climatic Laboratory. Methods were developed for generating moderately uniform and stabl...

Is the gas-particle partitioning in alpha-pinene secondary organic aerosol reversible?

NASA Astrophysics Data System (ADS)

Grieshop, Andrew P.; Donahue, Neil M.; Robinson, Allen L.

2007-07-01

This paper discusses the reversibility of gas-particle partitioning in secondary organic aerosol (SOA) formed from α-pinene ozonolysis in a smog chamber. Previously, phase partitioning has been studied quantitatively via SOA production experiments and qualitatively by perturbing temperature and observing particle evaporation. In this work, two methods were used to isothermally dilute the SOA: an external dilution sampler and an in-chamber technique. Dilution caused some evaporation of SOA, but repartitioning took place on a time scale of tens of minutes to hours-consistent with an uptake coefficient on the order of 0.001-0.01. However, given sufficient time, α-pinene SOA repartitions reversibly based on comparisons with data from conventional SOA yield experiments. Further, aerosol mass spectrometer (AMS) data indicate that the composition of SOA varies with partitioning. These results suggest that oligomerization observed in high-concentration laboratory experiments may be a reversible process and underscore the complexity of the kinetics of formation and evaporation of SOA.

A NEW NON-AMBIGUOUS ANALYTICAL TECHNIQUE FOR THE IDENTIFICATION OF AEROSOL OXYGENATED COMPOUNDS

EPA Science Inventory

The most important organic products identified in the particle phase from field samples and from smog chamber experiments are polar oxygenated compounds containing one, two, three or more oxygenated functional groups (e.g. hydroxyl, carboxylic acid, ketone). Current procedures ...

Multi-property characterization chamber for geophysical-hydrological investigations of hydrate bearing sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seol, Yongkoo, E-mail: Yongkoo.Seol@netl.doe.gov; Choi, Jeong-Hoon; Dai, Sheng

With the increase in the interest of producing natural gas from methane hydrates as well as potential risks of massive hydrate dissociation in the context of global warming, studies have recently shifted from pure hydrate crystals to hydrates in sediments. Such a research focus shift requires a series of innovative laboratory devices that are capable of investigating various properties of hydrate-bearing sediments (HBS). This study introduces a newly developed high pressure testing chamber, i.e., multi-property characterization chamber (MPCC), that allows simultaneous investigation of a series of fundamental properties of HBS, including small-strain stiffness (i.e., P- and S-waves), shear strength, large-strainmore » deformation, stress-volume responses, and permeability. The peripheral coolant circulation system of the MPCC permits stable and accurate temperature control, while the core holder body, made of aluminum, enables X-ray computer tomography scanning to be easily employed for structural and morphological characterization of specimens. Samples of hydrate-bearing sediments are held within a rubber sleeve inside the chamber. The thick sleeve is more durable and versatile than thin membranes while also being much softer than oedometer-type chambers that are incapable of enabling flow tests. Bias introduced by the rubber sleeve during large deformation tests are also calibrated both theoretically and experimentally. This system provides insight into full characterization of hydrate-bearing sediments in the laboratory, as well as pressure core technology in the field.« less

Automated, low-power chamber system for measuring nitrous oxide emissions

USDA-ARS?s Scientific Manuscript database

Continuous measurement of soil emissions is needed to constrain estimates of N2O loss to the atmosphere. Here, we describe the performance of a low-power, automated chamber system that can continuously measure N2O soil emissions, powered by wind and solar power. Laboratory testing of the Teledyne N2...

Dark Matter Search Results from the PICO - 60 C 3 F 8 Bubble Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amole, C.; Ardid, M.; Arnquist, I. J.

2017-06-01

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C 3F 8 located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60C 3F 8 exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one event per month.

Differential cardiac effects in rats exposed to atmospheric ...

EPA Pesticide Factsheets

The results of this study demonstrate that atmospheric smog generated from both isoprene and toluene cause cardiac effects in rats. In addition, it appears that smog from toluene is more toxic in terms of cardiac arrhythmogenicity. Smog, which is a complex mixture of particulate matter and gaseous irritants (ozone, sulfur dioxide, reactive aldehydes), as well as components which react with sunlight to form secondary pollutants, has recently been linked to increased risk of adverse cardiac responses. The components, and therefore health effects, of atmospheric smog are determined by the fuel used to generate them. In this study we examined the difference between isoprene- and toluene-generated smog in causing cardiac effects in rats and hypothesized that both atmospheres would cause cardiac electrical and functional changes in rats. Male Wistar-Kyoto rats were exposed to either atmospheric smog generated by the USEPA’s mobile reaction chamber using either isoprene or toluene, or filtered air for four hours. One day later, rats were anesthetized and left ventricular functional responses to dobutamine were measured using a Millar probe and arrhythmia sensitivity to aconitine. Baseline left ventricular pressure (LVP) was lower in toluene-exposed animals but not isoprene when compared to air. Increases in LVP with increasing doses of dobutamine were impaired only in toluene-exposed rats. Both isoprene and toluene impaired the rate of ventri

Numerical Simulation of Earth Pressure on Head Chamber of Shield Machine with FEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Shouju; Kang Chengang; Sun, Wei

2010-05-21

Model parameters of conditioned soils in head chamber of shield machine are determined based on tree-axial compression tests in laboratory. The loads acting on tunneling face are estimated according to static earth pressure principle. Based on Duncan-Chang nonlinear elastic constitutive model, the earth pressures on head chamber of shield machine are simulated in different aperture ratio cases for rotating cutterhead of shield machine. Relationship between pressure transportation factor and aperture ratio of shield machine is proposed by using aggression analysis.

Whistler wave propagation in the antenna near and far fields in the Naval Research Laboratory Space Physics Simulation Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blackwell, David D.; Walker, David N.; Amatucci, William E.

2010-01-15

In previous papers, early whistler propagation measurements were presented [W. E. Amatucci et al., IEEE Trans. Plasma Sci. 33, 637 (2005)] as well as antenna impedance measurements [D. D. Blackwell et al., Phys. Plasmas 14, 092106 (2007)] performed in the Naval Research Laboratory Space Physics Simulation Chamber (SPSC). Since that time there have been major upgrades in the experimental capabilities of the laboratory in the form of improvement of both the plasma source and antennas. This has allowed access to plasma parameter space that was previously unattainable, and has resulted in measurements that provide a significantly clearer picture of whistlermore » propagation in the laboratory environment. This paper presents some of the first whistler experimental results from the upgraded SPSC. Whereas previously measurements were limited to measuring the cyclotron resonance cutoff and elliptical polarization indicative of the whistler mode, now it is possible to experimentally plot the dispersion relation itself. The waves are driven and detected using balanced dipole and loop antennas connected to a network analyzer, which measures the amplitude and phase of the wave in two dimensions (r and z). In addition the frequency of the signals is also swept over a range of several hundreds of megahertz, providing a comprehensive picture of the near and far field antenna radiation patterns over a variety of plasma conditions. The magnetic field is varied from a few gauss to 200 G, with the density variable over at least 3 decades from 10{sup 7} to 10{sup 10} cm{sup -3}. The waves are shown to lie on the dispersion surface for whistler waves, with observation of resonance cones in agreement with theoretical predictions. The waves are also observed to propagate without loss of amplitude at higher power, a result in agreement with previous experiments and the notion of ducted whistlers.« less

IACP (INTEGRATED AIR CANCER PROJECT) EMISSIONS: TRANSFORMATIONS AND FATE

EPA Science Inventory

As part of the Integrated Air Cancer Project (IACP), diluted emissions from wood stoves and automobiles were injected into a Teflon smog chamber and irradiated to simulate their photochemical transformation in the atmosphere. Changes in the chemical composition and physical prope...

AGATE: A High Energy Gamma-Ray Telescope Using Drift Chambers

NASA Astrophysics Data System (ADS)

Mukherjee, R.; Dingus, B. L.; Esposito, J. A.; Bertsch, D. L.; Cuddapah, R.; Fichtel, C. E.; Hartman, R. C.; Hunter, S. D.; Thompson, D. J.

1996-01-01

The exciting results from the highly successful Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory (CGRO) has contributed significantly to increasing our understanding of high energy gamma-ray astronomy. A follow-on mission to EGRET is needed to continue these scientific advances as well as to address the several new scientific questions raised by EGRET. Here we describe the work being done on the development of the Advanced Gamma-Ray Astronomy Telescope Experiment (AGATE), visualized as the successor to EGRET. In order to achieve the scientific goals, AGATE will have higher sensitivity than EGRET in the energy range 30 MeV to 30 GeV, larger effective area, better angular resolution, and an extended low and high energy range. In its design, AGATE will follow the tradition of the earlier gamma-ray telescopes, SAS-2, COS B, and EGRET, and will have the same four basic components of an anticoincidence system, directional coincidence system, track imaging, and energy measurement systems. However, due to its much larger size, AGATE will use drift chambers as its track imaging system rather than the spark chambers used by EGRET. Drift chambers are an obvious choice as they have less deadtime per event, better spatial resolution, and are relatively easy and inexpensive to build. Drift chambers have low power requirements, so that many layers of drift chambers can be included. To test the feasibility of using drift chambers, we have constructed a prototype instrument consisting of a stack of sixteen 1/2m × 1/2m drift chambers and have measured the spatial resolution using atmospheric muons. The results on the drift chamber performance in the laboratory are presented here.

Mixing-Chamber Preamplifier for Spin Qubit Readout

NASA Astrophysics Data System (ADS)

Curry, Matthew; Mounce, Andrew; England, Troy; Manginell, Ronald; Wendt, Joel; Pluym, Tammy; Carr, Stephen; Carroll, Malcolm

Spin qubit states are often read out with a nearby charge sensor. To improve signal-to-noise ratio (SNR) and bandwidth, we amplify a charge sensor with a low-current-bias, silicon-germanium heterojunction-bipolar-transistor (HBT). The HBT is located at the mixing chamber of a dilution refrigerator, which minimizes parasitic capacitance and amplifies signal before fridge noise is introduced. Using the HBT-charge-sensor circuit, we tune a few-electron quantum dot (QD) into resonance with a donor-like object and observe singlet-triplet (ST) behavior. ST separation in this MOS donor-implanted-QD molecular system is measured using magnetospectroscopy to be approximately 100 μeV. The low current bias of the HBT minimizes both heating of the charge-sensed QD as well as maintains an overall low power at the mixing chamber. HBT bias impact on QD electron temperature is examined and we find that the HBT preamplifier can operate at around 100 nW with a current gain of around 500 without influencing the electron temperature, which is around 150 mK. We will also examine single-shot readout of a charge state using the HBT preamplifier. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

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.

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.

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.

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.

SCOUT: a small vacuum chamber for nano-wire grid polarizer tests in the ultraviolet band

NASA Astrophysics Data System (ADS)

Landini, F.; Pancrazzi, M.; Totaro, M.; Pennelli, G.; Romoli, M.

2012-01-01

Within the Section of Astronomy of the Department of Physics and Astronomy of the University of Firenze, Italy), the XUVLab laboratory is active since 1998 dedicated to technological development, mainly UV oriented. The technological research is focused both on electronics and optics. Our last approach is dedicated to the development of innovative wiregrid polarizers optimized to work in transmission at 121.6 nm. The manufacturing of such optical devices requires advanced technological expertise and suitable experimental structures. First, nanotechnology capability is necessary, in order to build several tiny parallel conductive lines separated by tens of nanometers on wide areas to be macroscopically exploitable in an optical laboratory. Moreover, the characterization of such an advanced optical device has to be performed in vacuum, being air absorptive at 121.6 nm. A dedicated small vacuum chamber, SCOUT (Small Chamber for Optical UV Tests) was developed within our laboratory in order to perform practical and fast measurements. SCOUT hosts an optical bench and is equipped with several opening flanges, in order to be as flexible as possible. The flexibility that has been reached with SCOUT allows us to use the chamber beyond the goals it was thought for. It is exploitable by whatever compact (within 1 m) optical experiment that investigates the UV band of the spectrum.

Ice nucleating particles measured during the laboratory and field intercomparisons FIN-2 and FIN-3 by the diffusion chamber FRIDGE

NASA Astrophysics Data System (ADS)

Weber, Daniel; Schrod, Jann; Curtius, Joachim; Haunold, Werner; Thomson, Erik; Bingemer, Heinz

2016-04-01

The measurement of atmospheric ice nucleating particles (INP) is still challenging. In the absence of easily applicable INP standards the intercomparison of different methods during collaborative laboratory and field workshops is a valuable tool that can shine light on the performance of individual methods for the measurement of INP [1]. FIN-2 was conducted in March 2015 at the AIDA facility in Karlsruhe as an intercomparison of mobile instruments for measuring INP [2]. FIN-3 was a field campaign at the Desert Research Institutes Storm Peak Laboratory in Colorado in September 2015 [3]. The FRankfurt Ice nucleation Deposition freezinG Experiment (FRIDGE) participated in both experiments. FRIDGE measures ice nucleating particles by electrostatic precipitation of aerosol particles onto Si-wafers in a collection unit, followed by activation, growth, and optical detection of ice crystals on the substrate in an isostatic diffusion chamber [4,5]. We will present and discuss results of our measurements of deposition/condensation INP and of immersion INP with FRIDGE during FIN-2 and FIN-3. Acknowledgements: The valuable contributions of the FIN organizers and their institutions, and of the FIN Workshop Science team are gratefully acknowledged. Our work was supported by Deutsche Forschungsgemeinschaft (DFG) under the Research Unit FOR 1525 (INUIT) and the EU FP7-ENV- 2013 BACCHUS project under Grant Agreement 603445.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sobrado, J. M., E-mail: sobradovj@inta.es; Martín-Soler, J.; Martín-Gago, J. A.

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

A versatile UHV transport and measurement chamber for neutron reflectometry under UHV conditions.

PubMed

Syed Mohd, A; Pütter, S; Mattauch, S; Koutsioubas, A; Schneider, H; Weber, A; Brückel, T

2016-12-01

We report on a versatile mini ultra-high vacuum (UHV) chamber which is designed to be used on the MAgnetic Reflectometer with high Incident Angle of the Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum in Garching, Germany. Samples are prepared in the adjacent thin film laboratory by molecular beam epitaxy and moved into the compact chamber for transfer without exposure to ambient air. The chamber is based on DN 40 CF flanges and equipped with sapphire view ports, a small getter pump, and a wobble stick, which serves also as sample holder. Here, we present polarized neutron reflectivity measurements which have been performed on Co thin films at room temperature in UHV and in ambient air in a magnetic field of 200 mT and in the Q-range of 0.18 Å -1 . The results confirm that the Co film is not contaminated during the polarized neutron reflectivity measurement. Herewith it is demonstrated that the mini UHV transport chamber also works as a measurement chamber which opens new possibilities for polarized neutron measurements under UHV conditions.

A versatile UHV transport and measurement chamber for neutron reflectometry under UHV conditions

NASA Astrophysics Data System (ADS)

Syed Mohd, A.; Pütter, S.; Mattauch, S.; Koutsioubas, A.; Schneider, H.; Weber, A.; Brückel, T.

2016-12-01

We report on a versatile mini ultra-high vacuum (UHV) chamber which is designed to be used on the MAgnetic Reflectometer with high Incident Angle of the Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum in Garching, Germany. Samples are prepared in the adjacent thin film laboratory by molecular beam epitaxy and moved into the compact chamber for transfer without exposure to ambient air. The chamber is based on DN 40 CF flanges and equipped with sapphire view ports, a small getter pump, and a wobble stick, which serves also as sample holder. Here, we present polarized neutron reflectivity measurements which have been performed on Co thin films at room temperature in UHV and in ambient air in a magnetic field of 200 mT and in the Q-range of 0.18 Å-1. The results confirm that the Co film is not contaminated during the polarized neutron reflectivity measurement. Herewith it is demonstrated that the mini UHV transport chamber also works as a measurement chamber which opens new possibilities for polarized neutron measurements under UHV conditions.

High Molecular Weight Dimer Esters in α-Pinene Secondary Organic Aerosol

NASA Astrophysics Data System (ADS)

Kristensen, Kasper; Cui, Tianqu; Zhang, Haofei; Gold, Avram; Glasius, Marianne; Surratt, Jason D.

2014-05-01

Monoterpenes, such as α-pinene, constitute an important group of biogenic volatile organic compounds (BVOC). Once emitted into the atmosphere α-pinene is removed by oxidization by the hydroxyl radical (OH), reactions with ozone (O3), and with nitrate radicals (NO3) resulting in the formation of first-generation oxidation products, such as semi-volatile carboxylic acids. In addition, higher molecular weight dimer esters originating from the oxidation of α-pinene have been observed in both laboratory-generated and ambient secondary organic aerosols (SOA). While recent studies suggest that the dimers are formed through esterification between carboxylic acids in the particle phase, the formation mechanism of the dimer esters is still ambiguous. In this work, we present the results of a series of smog chamber experiments to assess the formation of dimer esters formed from the oxidation of α-pinene. Experiments were conducted in the University of North Carolina (UNC) dual outdoor smog chamber facility to investigate the effect of oxidant species (OH versus O3), relative humidity (RH), and seed aerosol acidity in order to obtain a better understanding of the conditions leading to the formation of the dimer esters and how these parameters may affect the formation and chemical composition of SOA. The chemical composition of α-pinene SOA was investigated by ultra-performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), and a total of eight carboxylic acids and four dimer esters were identified, constituting between 8 and 12 % of the total α-pinene SOA mass.

Zero-gravity cloud physics laboratory: Candidate experiments definition and preliminary concept studies

NASA Technical Reports Server (NTRS)

Eaton, L. R.; Greco, R. V.; Hollinden, A. B.

1973-01-01

The candidate definition studies on the zero-g cloud physics laboratory are covered. This laboratory will be an independent self-contained shuttle sortie payload. Several critical technology areas have been identified and studied to assure proper consideration in terms of engineering requirements for the final design. Areas include chambers, gas and particle generators, environmental controls, motion controls, change controls, observational techniques, and composition controls. This unique laboratory will allow studies to be performed without mechanical, aerodynamics, electrical, or other type techniques to support the object under study. This report also covers the candidate experiment definitions, chambers and experiment classes, laboratory concepts and plans, special supporting studies, early flight opportunities and payload planning data for overall shuttle payload requirements assessments.

MOLECULAR SPECIATION OF SECONDARY ORGANIC AEROSOL FROM PHOTOOXIDATION OF THE HIGHER ALKENES: 1-OCTENE AND 1-DECENE. (R824970)

EPA Science Inventory

Outdoor smog chamber photooxidations to determine the molecular composition of secondary organic aerosol (SOA) from 1-octene and 1-decene in sunlight-irradiated hydrocarbon-NO_x mixtures are reported. The observed products are consistent with the current under...

Peltier-based cloud chamber

NASA Astrophysics Data System (ADS)

Nar, Sevda Yeliz; Cakir, Altan

2018-02-01

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

Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Flux

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Morgan P.; Groh, Tyler A.; Parkin, Timothy B.

Quantification of soil gas flux using the static chamber method is labor intensive. The number of chambers that can be sampled is limited by the spacing between chambers and the availability of trained research technicians. An automated system for collecting gas samples from chambers in the field would eliminate the need for personnel to return to the chamber during a flux measurement period and would allow a single technician to sample multiple chambers simultaneously. This study describes Chamber Automated Sampling Equipment (FluxCASE) to collect and store chamber headspace gas samples at assigned time points for the measurement of soil gasmore » flux. The FluxCASE design and operation is described, and the accuracy and precision of the FluxCASE system is evaluated. In laboratory measurements of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) concentrations of a standardized gas mixture, coefficients of variation associated with automated and manual sample collection were comparable, indicating no loss of precision. In the field, soil gas fluxes measured from FluxCASEs were in agreement with manual sampling for both N2O and CO2. Slopes of regression equations were 1.01 for CO2 and 0.97 for N2O. The 95% confidence limits of the slopes of the regression lines included the value of one, indicating no bias. Additionally, an expense analysis found a cost recovery ranging from 0.6 to 2.2 yr. Implementing the FluxCASE system is an alternative to improve the efficiency of the static chamber method for measuring soil gas flux while maintaining the accuracy and precision of manual sampling.« less

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.

A smog chamber study coupling a photoionization aerosol electron/ion spectrometer to VUV synchrotron radiation: organic and inorganic-organic mixed aerosol analysis

NASA Astrophysics Data System (ADS)

Baeza-Romero, María Teresa; Gaie-Levrel, Francois; Mahjoub, Ahmed; López-Arza, Vicente; Garcia, Gustavo A.; Nahon, Laurent

2016-07-01

A reaction chamber was coupled to a photoionization aerosol time-of-flight mass spectrometer based on an electron/ion coincidence scheme and applied for on-line analysis of organic and inorganic-organic mixed aerosols using synchrotron tunable vacuum ultraviolet (VUV) photons as the ionization source. In this proof of principle study, both aerosol and gas phase were detected simultaneously but could be differentiated. Present results and perspectives for improvement for this set-up are shown in the study of ozonolysis ([O3] = 0.13-3 ppm) of α-pinene (2-3 ppm), and the uptake of glyoxal upon ammonium sulphate. In this work the ozone concentration was monitored in real time, together with the particle size distributions and chemical composition, the latter taking advantage of the coincidence spectrometer and the tuneability of the synchrotron radiation as a soft VUV ionization source.

Evaluation of the smoke density chamber as an apparatus for fire toxicity screening tests

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Labossiere, L. A.

1976-01-01

The smoke density chamber is perhaps the most widely used apparatus for smoke measurements. Because of its availability, it has been proposed as an apparatus for evaluating fire toxicity. The standard apparatus and procedure were not found suitable for toxicity screening tests using laboratory animals, because not enough materials of interest produced animal mortality or even incapacitation under standard test conditions. With modifications, the chamber offers greater promise as a screening tool, but other tests specifically designed to measure relative toxicity may be more cost-effective. Where one-dimensional heat flux is a requirement, the chamber is the most suitable apparatus available. It should be improved in regard to visibility of animals and ease of cleaning.

Characteristics Air Flow in Room Chamber Test Refrigerator Household Energy Consumption with Inlet Flow Variation

NASA Astrophysics Data System (ADS)

Susanto, Edy; Idrus Alhamid, M.; Nasruddin; Budihardjo

2018-03-01

Room Chamber is the most important in making a good Testing Laboratory. In this study, the 2-D modeling conducted to assess the effect placed the inlet on designing a test chamber room energy consumption of household refrigerators. Where the geometry room chamber is rectangular and approaching the enclosure conditions. Inlet varied over the side parallel to the outlet and compared to the inlet where the bottom is made. The purpose of this study was to determine and define the characteristics of the airflow in the room chamber using CFD simulation. CFD method is used to obtain flow characteristics in detail, in the form of vector flow velocity and temperature distribution inside the chamber room. The result found that the position of the inlet parallel to the outlet causes air flow cannot move freely to the side of the floor, even flow of air moves up toward the outlet. While by making the inlet is below, the air can move freely from the bottom up to the side of the chamber room wall as well as to help uniform flow.

The ribbon-cutting ceremony unveils the reactivated altitude chamber inside the O&C high bay

NASA Technical Reports Server (NTRS)

1999-01-01

Inside the Operations and Checkout Building high bay, Center Director Roy Bridges remarks on the accomplishment of the joint NASA/Boeing team in renovating an altitude chamber formerly used on the Apollo program. Project team members, management, media and onlookers are present for the ribbon cutting. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test.

ß-CARYOPHYLLINIC ACID: AN ATMOSPHERIC TRACER FOR ß-CARYOPHYLLENE SECONDARY ORGANIC AEROSOL

EPA Science Inventory

The chemical compositions of ambient PM_2.5 samples, collected in Research Triangle Park, North Carolina, USA, and a sample of secondary organic aerosol, formed by irradiating a mixture of the sesquiterpene, ß-caryophyllene, and oxides of nitrogen in a smog chamber, wer...

GAS-PARTICLE PARTITIONING OF SEMI-VOLATILE ORGANICS ON ORGANIC AEROSOLS USING A PREDICTIVE ACTIVITY COEFFICIENT MODEL: ANALYSIS OF THE EFFECTS OF PARAMETER CHOICES ON MODEL PERFORMANCE. (R826771)

EPA Science Inventory

The partitioning of a diverse set of semivolatile organic compounds (SOCs) on a variety of organic aerosols was studied using smog chamber experimental data. Existing data on the partitioning of SOCs on aerosols from wood combustion, diesel combustion, and the ANALYSIS OF SECONDARY ORGANIC AEROSOL COMPOUNDS FROM THE PHOTOOXIDATION OF D-LIMONENE IN THE PRESENCE OF NO X AND THEIR DETECTION IN AMBIENT PM 2.5

EPA Science Inventory

Chemical analysis of secondary organic aerosol (SOA) from the photooxidation of a d-limonene/NOx/air mixture was carried out. SOA, generated in a smog chamber, was collected on Zefluor filters. To determine the structural characteristics of the compounds, the filter sample...

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.

The Harvard Fatigue Laboratory: contributions to World War II.

PubMed

Folk, G Edgar

2010-09-01

The war contributions of the Harvard Fatigue Laboratory in Cambridge, MA, were recorded in 169 Technical Reports, most of which were sent to the Office of the Quartermaster General. Earlier reports were sent to the National Research Council and the Office of Scientific Research and Development. Many of the reports from 1941 and later dealt with either physical fitness of soldiers or the energetic cost of military tasks in extreme heat and cold. New military emergency rations to be manufactured in large quantities were analyzed in the Fatigue Laboratory and then tested in the field. Newly designed cold weather clothing was tested in the cold chamber at -40 degrees F, and desired improvements were made and tested in the field by staff and soldiers in tents and sleeping bags. Electrically heated clothing was designed for high-altitude flight crews and tested both in laboratory chambers and field tests before being issued. This eye witness account of the Harvard Fatigue Laboratory during World War II was recorded by Dr. G. Edgar Folk, who is likely the sole surviving member of that famous laboratory.

Primary Exhaust Cooler at the Propulsion Systems Laboratory

NASA Image and Video Library

1952-09-21

One of the two primary coolers at the Propulsion Systems Laboratory at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Engines could be run in simulated altitude conditions inside the facility’s two 14-foot-diameter and 24-foot-long test chambers. The Propulsion Systems Laboratory was the nation’s only facility that could run large full-size engine systems in controlled altitude conditions. At the time of this photograph, construction of the facility had recently been completed. Although not a wind tunnel, the Propulsion Systems Laboratory generated high-speed airflow through the interior of the engine. The air flow was pushed through the system by large compressors, adjusted by heating or refrigerating equipment, and de-moisturized by air dryers. The exhaust system served two roles: reducing the density of the air in the test chambers to simulate high altitudes and removing hot gases exhausted by the engines being tested. It was necessary to reduce the temperature of the extremely hot engine exhaust before the air reached the exhauster equipment. As the air flow exited through exhaust section of the test chamber, it entered into the giant primary cooler seen in this photograph. Narrow fins or vanes inside the cooler were filled with water. As the air flow passed between the vanes, its heat was transferred to the cooling water. The cooling water was cycled out of the system, carrying with it much of the exhaust heat.

50. BOILER CHAMBER No. 1, LOOKING SOUTHEAST BETWEEN CHAMBER AND ...

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

50. BOILER CHAMBER No. 1, LOOKING SOUTHEAST BETWEEN CHAMBER AND ENCLOSURE (LOCATION III) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

Anterior chamber paracentesis to improve diagnosis and treatment of infectious uveitis in South Africa.

PubMed

Schaftenaar, Erik; Lecuona, Karin; Baarsma, Seerp; Meenken, Christina; Verjans, Georges; McIntyre, James; Peters, Remco

2015-09-22

Infectious uveitis is a significant cause of blindness in South Africa, especially among HIV-infected individuals. The visual outcome of uveitis depends on early clinical and laboratory diagnosis to guide therapeutic intervention. Analyses of aqueous humor, obtained by anterior chamber paracentesis, directs the differential diagnosis in infectious uveitis. However, although safe and potentially cost-effective, diagnostic anterior chamber paracentesis is not common practice in ophthalmic care across Africa. We seek to draw attention to this important procedure that could improve the diagnosis and prognosis of infectious uveitis.

61. BOILER CHAMBER No. 2, LOOKING SOUTHWEST BETWEEN CHAMBER AND ...

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

61. BOILER CHAMBER No. 2, LOOKING SOUTHWEST BETWEEN CHAMBER AND CONCRETE ENCLOSURE (LOCATION PPP) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

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

Chamber study of PCBemissions from caulking materials and ...

EPA Pesticide Factsheets

The emissions of polychlorinated biphenyl (PCB) congeners from 13 caulk samples were tested in a micro-chamber system. Twelve samples were from PCB-contaminated buildings and one was prepared in the laboratory. Nineteen light ballasts collected from buildings that represent 13 different models from five manufacturers were tested in 53-liter environmental chambers. The rates of PCB congener emissions from caulking materials and light ballasts were determined. Several factors that may have affected the emission rates were evaluated. The experimentally determined emission factors showed that, for a given PCB congener, there is a linear correlation between the emission factor and the concentration of the PCB congener in the source. Furthermore, the test results showed that an excellent log-linear correlation exists between the normalized emission factor and the vapor pressure (coefficient of determination, r2 ≥0.8846). The PCB congener emissions from ballasts at or near room temperature were relatively low with or without electrical load. However, the PCB congener emission rates increased significantly as the temperature increased. The results of this research provide new data and models for ranking the primary sources of PCBs and supports the development and refinement of exposure assessment models for PCBs. This study supplemented and complemented the field measurements in buildings conducted by U.S. EPA National Exposure Research Laboratory by providing a bette

41. AUXILIARY CHAMBER, CONCRETE ENCLOSURE CHAMBER AIR LOCK (EXTERIOR), LOOKING ...

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

41. AUXILIARY CHAMBER, CONCRETE ENCLOSURE CHAMBER AIR LOCK (EXTERIOR), LOOKING NORTHEAST FROM SOUTHWEST CORNER (LOCATION AAA) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

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

New Submersed Chamber for Calibration of Relative Humidity Instruments at HMI/FSB-LPM

NASA Astrophysics Data System (ADS)

Sestan, D.; Zvizdic, D.; Sariri, K.

2018-02-01

This paper gives a detailed description of a new chamber designed for calibration of relative humidity (RH) instruments at Laboratory for Process Measurement (HMI/FSB-LPM). To the present time, the calibrations of RH instruments at the HMI/FSB-LPM were done by comparison method using a climatic chamber of large volume and calibrated dew point hygrometer with an additional thermometer. Since 2010, HMI/FSB-LPM in cooperation with Centre for Metrology and Accreditation in Finland (MIKES) developed the two primary dew point generators which cover the dew point temperature range between - 70 {°}C and 60 {°}C. In order to utilize these facilities for calibrations of the RH instruments, the new chamber was designed, manufactured and installed in the existing system, aiming to extend its range and reduce the related calibration uncertainties. The chamber construction allows its use in a thermostatic bath of larger volume as well as in the climatic chambers. In the scope of this paper, performances of the new chamber were tested while it was submersed in a thermostated bath. The chamber can simultaneously accommodate up to three RH sensors. In order to keep the design of the chamber simple, only cylindrical RH sensors detachable from display units can be calibrated. Possible optimizations are also discussed, and improvements in the design proposed. By using the new chamber, HMI/FSB-LPM reduced the expanded calibration uncertainties (level of confidence 95 %, coverage factor k=2) from 0.6 %rh to 0.25 %rh at 30 %rh (23 {°}C), and from 0.8 %rh to 0.53 %rh at 70 %rh (23 {°}C).

THE PHOTOCHEMICAL FORMATION AND GAS-PARTICLE PARTITIONING OF OXIDATION PRODUCTS OF DECAMETHYL CYCLOPENTASILOXANE AND DECAMETHYL TETRASILOXANE IN THE ATMOSPHERE. (R826771)

EPA Science Inventory

Abstract

Decamethyl cyclopentasiloxane (D₅) and decamethyl tetrasiloxane (MD₂M) were injected into a smog chamber containing fine Arizona road dust particles (95% surface area <2.6 Formation of Organic Tracers for Isoprene SOA under Acidic Conditions

EPA Science Inventory

The chemical compositions of a series of secondary organic aerosol (SOA) samples, formed by irradiating mixtures of isoprene and NO in a smog chamber in the absence or presence of acidic aerosols, were analyzed using derivatization-based GC-MS methods. In addition to the known is...

Introductory study of the chemical behavior of jet emissions in photochemical smog. [computerized simulation

NASA Technical Reports Server (NTRS)

Whitten, G. Z.; Hogo, H.

1976-01-01

Jet aircraft emissions data from the literature were used as initial conditions for a series of computer simulations of photochemical smog formation in static air. The chemical kinetics mechanism used in these simulations was an updated version which contains certain parameters designed to account for hydrocarbon reactivity. These parameters were varied to simulate the reaction rate constants and average carbon numbers associated with the jet emissions. The roles of surface effects, variable light sources, NO/NO2 ratio, continuous emissions, and untested mechanistic parameters were also assessed. The results of these calculations indicate that the present jet emissions are capable of producing oxidant by themselves. The hydrocarbon/nitrous oxides ratio of present jet aircraft emissions is much higher than that of automobiles. These two ratios appear to bracket the hydrocarbon/nitrous oxides ratio that maximizes ozone production. Hence an enhanced effect is seen in the simulation when jet exhaust emissions are mixed with automobile emissions.

Growth, chamber building rate and reproduction time of Palaeonummulites venosus under natural conditions.

NASA Astrophysics Data System (ADS)

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

2017-04-01

Investigations on Palaeonummulites venosus using the natural laboratory approach for determining chamber building rate, test diameter increase rate, reproduction time and longevity is based on the decomposition of monthly obtained frequency distributions based on chamber number and test diameter into normal-distributed components. The shift of the component parameters 'mean' and 'standard deviation' during the investigation period of 15 months was used to calculate Michaelis-Menten functions applied to estimate the averaged chamber building rate and diameter increase rate under natural conditions. The individual dates of birth were estimated using the inverse averaged chamber building rate and the inverse diameter increase rate fitted by the individual chamber number or the individual test diameter at the sampling date. Distributions of frequencies and densities (i.e. frequency divided by sediment weight) based on chamber building rate and diameter increase rate resulted both in a continuous reproduction through the year with two peaks, the stronger in May /June determined as the beginning of the summer generation (generation1) and the weaker in November determined as the beginning of the winter generation (generation 2). This reproduction scheme explains the existence of small and large specimens in the same sample. Longevity, calculated as the maximum difference in days between the individual's birth date and the sampling date seems to be round about one year, obtained by both estimations based on the chamber building rate and the diameter increase rate.

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.

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.

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)

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Some new tests at the Gottingen laboratory

NASA Technical Reports Server (NTRS)

1921-01-01

The tests at the Gottingen laboratory included: friction tests on a surface treated with omelette, verification tests on the M.V.A. 356 wing, and comparative tests of wing no. 36 at the Eiffel laboratory. The examination of all these experiments leads to the belief that, at large incidences, the speeds registered by the suction manometer of the testing chamber of the Eiffel laboratory wind tunnel are, owing to pressure drop, greater than the actual speeds. Therefore, the values of k(sub x) and k(sub y) measured at the Eiffel laboratory at large incidences are too low.

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.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Documentation of Plant Growth in an EPO-Kit C Chamber taken during Expedition 15

NASA Image and Video Library

2007-08-20

ISS015-E-23475 (20 Aug. 2007) --- Close-up view of a plant growth experiment in an Education Payload Operations experiment collapsible growth chamber (labeled "Lettuce") photographed in the U.S. Laboratory or Destiny module aboard the International Space Station during Expedition 15.

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.

Detecting special nuclear material using a neutron time projection chamber

NASA Astrophysics Data System (ADS)

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

2010-02-01

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

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.

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.

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

DOE PAGES

Amole, C.; Ardid, M.; Asner, D. M.; ...

2016-03-01

We reported new data from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF 3I and located in the SNOLAB underground laboratory. PICO-60 is the largest bubble chamber to search for dark matter to date. With an analyzed exposure of 92.8 live-days, PICO-60 exhibits the same excellent background rejection observed in smaller bubble chambers. Alpha decays in PICO-60 exhibit frequency-dependent acoustic calorimetry, similar but not identical to that reported recently in a C 3F 8 bubble chamber. PICO-60 also observes a large population of unknown background events, exhibiting acoustic, spatial, and timingmore » behaviors inconsistent with those expected from a dark matter signal. We found these behaviors allow for analysis cuts to remove all background events while retaining 48.2%of the exposure. Stringent limits on WIMPs interacting via spin-dependent proton and spin-independent processes are set, and the interpretation of the DAMA/LIBRA modulation signal as dark matter interacting with iodine nuclei is ruled out.« less

Dark matter search results from the PICO-60 CF 3 I bubble chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amole, C.; Ardid, M.; Asner, D. M.

2016-03-01

New data are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 36.8 kg of CF3I and located in the SNOLAB underground laboratory. PICO-60 is the largest bubble chamber to search for dark matter to date. With an analyzed exposure of 92.8 livedays, PICO-60 exhibits the same excellent background rejection observed in smaller bubble chambers. Alpha decays in PICO-60 exhibit frequency-dependent acoustic calorimetry, similar but not identical to that reported recently in a C3F8 bubble chamber. PICO-60 also observes a large population of unknown background events, exhibiting acoustic, spatial, and timing behaviors inconsistent withmore » those expected from a dark matter signal. These behaviors allow for analysis cuts to remove all background events while retaining 48.2% of the exposure. Stringent limits on weakly interacting massive particles interacting via spin-dependent proton and spin-independent processes are set, and most interpretations of the DAMA/LIBRA modulation signal as dark matter interacting with iodine nuclei are ruled out.« less

The ribbon-cutting ceremony unveils the reactivated altitude chamber inside the O&C high bay

NASA Technical Reports Server (NTRS)

1999-01-01

Cutting a red ribbon for the unveiling of a newly renovated altitude chamber are (left to right) Tommy Mack, project manager, NASA; Steve Francois, director, Space Station and Shuttle Payloads; Sterling Walker, director, Engineering Development; Roy Bridges, director, Kennedy Space Center; Jay Greene, International Space Station manager for Technical; Michael Terry, project manager, Boeing; and Terry Smith, director of Engineering, Boeing Space Coast Operations. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test.

Photooxidation of farnesene mixtures in the presence of NOx: Analysis of reaction products and their implication to ambient PM2.5

EPA Science Inventory

Chemical analysis of SOA produced from the irradiation of a mixture of α/β-farnesene/NOx was conducted in a 14.5 m3 smog chamber. SOA collected on glass-fiber filters was solvent extracted, derivatized using BSTFA, and analyzed by GC–MS. Gas-phase products were a...

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

SCOUT: small chamber for optical UV tests

NASA Astrophysics Data System (ADS)

Pancrazzi, M.; Landini, F.; Romoli, M.; Totaro, M.; Pennelli, G.

2017-11-01

SCOUT is the acronym of the new facility developed within the XUVLab laboratory of the Department of Physics and Astronomy of the University of Florence. SCOUT stands for "Small Chamber for Optical UV Tests" and has been designed to perform practical and fast measurements for those experiments requiring an evacuated environment. SCOUT has been thought, designed and manufactured by paying a particular attention to its flexibility and adaptability. The functionality and the capabilities of SCOUT have been recently tested in a measurement campaign to characterize an innovative wire-grid polarizer optimized to work in transmission in the UV band. This paper provides a description of the overall manufactured system and its performance and shows the additional resources available at the XUVLab laboratory in Florence that make SCOUT exploitable by whatever compact (within 1 m) optical experiment that investigates the UV band of the spectrum.

Biases of chamber methods for measuring soil CO2 efflux demonstrated with a laboratory apparatus.

Treesearch

S. Mark Nay; Kim G. Mattson; Bernard T. Bormann

1994-01-01

Investigators have historically measured soil CO2 efflux as an indicator of soil microbial and root activity and more recently in calculations of carbon budgets. The most common methods estimate CO2 efflux by placing a chamber over the soil surface and quantifying the amount of CO2 entering the...

Crew Systems Laboratory/Building 7. Historical Documentation

NASA Technical Reports Server (NTRS)

Slovinac, Patricia

2011-01-01

Building 7 is managed by the Crew and Thermal Systems Division of the JSC Engineering Directorate. Originally named the Life Systems Laboratory, it contained five major test facilities: two advanced environmental control laboratories and three human-rated vacuum chambers (8 , 11 , and the 20 ). These facilities supported flight crew familiarization and the testing and evaluation of hardware used in the early manned spaceflight programs, including Gemini, Apollo, and the ASTP.

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.

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.

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.

RADIATION MONITOR CONTAINING TWO CONCENTRIC IONIZATION CHAMBERS AND MEANS FOR INSULATING THE SEPARATE CHAMBERS

DOEpatents

Braestrup, C.B.; Mooney, R.T.

1964-01-21

This invention relates to a portable radiation monitor containing two concentric ionization chambers which permit the use of standard charging and reading devices. It is particularly adapted as a personnel x-ray dosimeter and to this end comprises a small thin walled, cylindrical conductor forming an inner energy dependent chamber, a small thin walled, cylindrical conductor forming an outer energy independent chamber, and polymeric insulation means which insulates said chambers from each other and holds the chambers together with exposed connections in a simple, trouble-free, and compact assembly substantially without variation in directional response. (AEC)

Atmospheric Oxidation of 1,3-Butadiene: Characterization of gas and aerosol reaction products and implication for PM2.5

EPA Science Inventory

Secondary organic aerosol (SOA) was generated by irradiating 1,3-butadiene (13BD) in the presence of H2O2 or NOx. Experiments were conducted in a smog chamber operated in either flow or batch mode. A filter/denuder sampling system was used for simultaneously collecting gas and pa...

Vibrating-chamber levitation systems

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Granett, D.; Lee, M. C. (Inventor)

1985-01-01

Systems are described for the acoustic levitation of objects, which enable the use of a sealed rigid chamber to avoid contamination of the levitated object. The apparatus includes a housing forming a substantially closed chamber, and means for vibrating the entire housing at a frequency that produces an acoustic standing wave pattern within the chamber.

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...

Sleeve reaction chamber system

DOEpatents

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

2009-08-25

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

Cyclic fatigue analysis of rocket thrust chambers. Volume 1: OFHC copper chamber low cycle fatigue

NASA Technical Reports Server (NTRS)

Miller, R. W.

1974-01-01

A three-dimensional finite element elasto-plastic strain analysis was performed for the throat section of a regeneratively cooled rocket combustion chamber. The analysis employed the RETSCP finite element computer program. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the chamber operating cycle. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen combustion chamber which was fatigue tested to failure. The computed strain range at typical chamber operating conditions was used in conjunction with oxygen-free, high-conductivity (OHFC) copper isothermal fatigue test data to predict chamber low-cycle fatigue life.

TRANSFORMATION AND TRANSPORT OF SEMI-VOLATILE ORGANIC COMPOUNDS FROM SOIL: MEASURING DICARBOXIMIDES IN A CHAMBER

EPA Science Inventory

A laboratory chamber was used to determine transport of a suspected anti-androgenic dicarboximide fungicide, vinclozolin (3,5-dichlorophenyl)-5-methyl-5-vinyl-oxzoli-dine-2,4-dione) and three degradation products from a North Carolina Piedmont aquic hapludult soil following a s...

24. PHOTOCOPY OF PLAN DRAWING. Quartermaster Research and Development Laboratory, ...

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

24. PHOTOCOPY OF PLAN DRAWING. Quartermaster Research and Development Laboratory, Natick, Mass, Climatic Building, First Floor Plan, Architectural. Drawing No. 35-07-01, Sheet 2 of 72, 1952, updated to 1985. (Source: NRDEC). - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

25. PHOTOCOPY OF PLAN DRAWING. Quartermaster Research and Development Laboratory, ...

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

25. PHOTOCOPY OF PLAN DRAWING. Quartermaster Research and Development Laboratory, Natick, Mass. Climatic Building, First Floor Plan, Refrigeration and Engineering. Drawing No. 35-07-01, Sheet 52 of 72, 1952. (Source: NRDEC). - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

Medical Biochemistry as Subdiscipline of Laboratory Medicine in Serbia.

PubMed

Jovičić, Snežana; Majkić-Singh, Nada

2017-04-01

Medical biochemistry is the usual name for clinical biochemistry or clinical chemistry in Serbia, and medical biochemist is the official name for the clinical chemist (or clinical biochemist). This is the largest sub-discipline of the laboratory medicine in Serbia. It includes all aspects of clinical chemistry, and also laboratory hematology with coagulation, immunology, etc. Medical biochemistry laboratories in Serbia and medical biochemists as a profession are part of Health Care System and their activities are regulated through: the Health Care Law and rules issued by the Chamber of Medical Biochemists of Serbia. The first continuous and organized education for Medical Biochemists (Clinical Chemists) in Serbia dates from 1945, when the Department of Medical Biochemistry was established at the Pharmaceutical Faculty in Belgrade. In 1987 at the same Faculty a five years undergraduate study program was established, educating Medical Biochemists under a special program. Since the academic year 2006/2007 the new five year undergraduate (according to Bologna Declaration) and four-year postgraduate program according to EC4 European Syllabus for Postgraduate Training in Clinical Chemistry and Laboratory Medicine has been established. The Ministry of Education and Ministry of Public Health accredited these programs. There are four requirements for practicing medical biochemistry in the Health Care System: University Diploma of the Faculty of Pharmacy (Study of Medical Biochemistry), successful completion of the professional exam at the Ministry of Health after completion of one additional year of obligatory practical training in the medical biochemistry laboratories, membership in the Serbian Chamber of Medical Biochemists and licence for skilled work issued by the Serbian Chamber of Medical Biochemists. In order to present laboratory medical biochemistry practice in Serbia this paper will be focused on the following: Serbian national legislation, healthcare services

Medical Biochemistry as Subdiscipline of Laboratory Medicine in Serbia

PubMed Central

Jovičić, Snežana

2017-01-01

Summary Medical biochemistry is the usual name for clinical biochemistry or clinical chemistry in Serbia, and medical biochemist is the official name for the clinical chemist (or clinical biochemist). This is the largest sub-discipline of the laboratory medicine in Serbia. It includes all aspects of clinical chemistry, and also laboratory hematology with coagulation, immunology, etc. Medical biochemistry laboratories in Serbia and medical biochemists as a profession are part of Health Care System and their activities are regulated through: the Health Care Law and rules issued by the Chamber of Medical Biochemists of Serbia. The first continuous and organized education for Medical Biochemists (Clinical Chemists) in Serbia dates from 1945, when the Department of Medical Biochemistry was established at the Pharmaceutical Faculty in Belgrade. In 1987 at the same Faculty a five years undergraduate study program was established, educating Medical Biochemists under a special program. Since the academic year 2006/2007 the new five year undergraduate (according to Bologna Declaration) and four-year postgraduate program according to EC4 European Syllabus for Postgraduate Training in Clinical Chemistry and Laboratory Medicine has been established. The Ministry of Education and Ministry of Public Health accredited these programs. There are four requirements for practicing medical biochemistry in the Health Care System: University Diploma of the Faculty of Pharmacy (Study of Medical Biochemistry), successful completion of the professional exam at the Ministry of Health after completion of one additional year of obligatory practical training in the medical biochemistry laboratories, membership in the Serbian Chamber of Medical Biochemists and licence for skilled work issued by the Serbian Chamber of Medical Biochemists. In order to present laboratory medical biochemistry practice in Serbia this paper will be focused on the following: Serbian national legislation, healthcare

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.

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

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.

2014-06-01

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

Demonstration of a chamber for strain mapping of steel specimens under mechanical load in a hydrogen environment by synchrotron radiation

NASA Astrophysics Data System (ADS)

Connolly, Matthew; Park, Jun-Sang; Bradley, Peter; Lauria, Damian; Slifka, Andrew; Drexler, Elizabeth

2018-06-01

We demonstrate a hydrogen gas chamber suitable for lattice strain measurements and capturing radiographs of a steel specimen under a mechanical load using high energy synchrotron x-rays. The chamber is suitable for static and cyclic mechanical loading. Experiments were conducted at the 1-ID-E end station of the Advanced Photon Source, Argonne National Laboratory. Diffraction patterns show a high signal-to-noise ratio suitable for lattice strain measurements for the specimen and with minimal scattering and overlap from the gas chamber manufactured from aluminum. In situ radiographs of a specimen in the hydrogen chamber show the ability to track a growing crack and to map the lattice strain around the crack with high spatial and strain resolution.

30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers, hot...

30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers, hot...

30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers, hot...

30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers, hot...

30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers, hot...

Vapor Wall Deposition in Chambers: Theoretical Considerations

NASA Astrophysics Data System (ADS)

McVay, R.; Cappa, C. D.; Seinfeld, J.

2014-12-01

In order to constrain the effects of vapor wall deposition on measured secondary organic aerosol (SOA) yields in laboratory chambers, Zhang et al. (2014) varied the seed aerosol surface area in toluene oxidation and observed a clear increase in the SOA yield with increasing seed surface area. Using a coupled vapor-particle dynamics model, we examine the extent to which this increase is the result of vapor wall deposition versus kinetic limitations arising from imperfect accommodation of organic species into the particle phase. We show that a seed surface area dependence of the SOA yield is present only when condensation of vapors onto particles is kinetically limited. The existence of kinetic limitation can be predicted by comparing the characteristic timescales of gas-phase reaction, vapor wall deposition, and gas-particle equilibration. The gas-particle equilibration timescale depends on the gas-particle accommodation coefficient αp. Regardless of the extent of kinetic limitation, vapor wall deposition depresses the SOA yield from that in its absence since vapor molecules that might otherwise condense on particles deposit on the walls. To accurately extrapolate chamber-derived yields to atmospheric conditions, both vapor wall deposition and kinetic limitations must be taken into account.

A Chemiluminescence Detector for Ozone Measurement.

ERIC Educational Resources Information Center

Carroll, H.; And Others

An ozone detector was built and evaluated for its applicability in smog chamber studies. The detection method is based on reaction of ozone with ethylene and measurement of resultant chemiluminescence. In the first phase of evaluation, the detector's response to ozone was studied as a function of several instrument parameters, and optimum…

SOA Formation from the Atmospheric Oxidation of 2-Methyl-3-Buten-2-ol and Its Implications for PM2.5

EPA Science Inventory

The formation of secondary organic aerosol (SOA) generated by irradiating 2-methyl-3-buten-2-01 (MBO) in the presence and/or absence of NO_x H₂O2, and/or SO₂ was examined. Experiments were conducted. in smog chambers operated either in dyna....

Atmospheric cloud physics laboratory project study

NASA Technical Reports Server (NTRS)

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

1976-01-01

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

[Fundamentals of quality control systems in medical-biochemical laboratories--the role of marketing].

PubMed

Topić, E; Turek, S

2000-01-01

The basic criterion for the overall quality system in medical biochemistry laboratories concerning equipment, premises and laboratory staff in primary health care (PHC) (Regulations on quality systems and good laboratory practice of the Croatian Medical Biochemists Chamber, 1995, Regulations on categorization of medical biochemistry laboratories of the Croatian Medical Biochemists Chamber, 1996, EC4: Essential criteria for quality systems in medical laboratories. Eur J Clin Chem Clin Biochem 1997 in medical biochemical laboratories included in the First Croatia health project, Primary health care subproject, has been met by the marketing approach to the project. The equipment ensuring implementation of the complete laboratory program (NN/96), more accurate and precise analytical procedures, and higher reliability of laboratory test results compared with previous equipment, has been purchased by an international tender. Uniform technology and methods of analysis have ensured high standards of good laboratory services, yielding test results than can be transferred from primary to secondary health care level. The new equipment has improved organization between central and detached medical biochemistry laboratory units, while the high quality requirement has led to improvement in the staff structure, e.g., medical biochemists have been employed in laboratories that had previously worked without such a professional. Equipment renewal has been accompanied by proper education for all levels of PHC professionals.

Mechanisms of differentiation in the Skaergaard magma chamber

NASA Astrophysics Data System (ADS)

Tegner, C.; Lesher, C. E.; Holness, M. B.; Jakobsen, J. K.; Salmonsen, L. P.; Humphreys, M. C. S.; Thy, P.

2012-04-01

The Skaergaard intrusion is a superb natural laboratory for studying mechanisms of magma chamber differentiation. The magnificent exposures and new systematic sample sets of rocks that solidified inwards from the roof, walls and floor of the chamber provide means to test the relative roles of crystal settling, diffusion, convection, liquid immiscibility and compaction in different regions of the chamber and in opposite positions relative to gravity. Examination of the melt inclusions and interstitial pockets has demonstrated that a large portion of intrusion crystallized from an emulsified magma chamber composed of immiscible silica- and iron-rich melts. The similarity of ratios of elements with opposite partitioning between the immiscible melts (e.g. P and Rb) in wall, floor and roof rocks, however, indicate that large-scale separation did not occur. Yet, on a smaller scale of metres to hundred of metres and close to the interface between the roof and floor rocks (the Sandwich Horizon), irregular layers and pods of granophyre hosted by extremely iron-rich cumulates point to some separation of the two liquid phases. Similar proportions of the primocryst (cumulus) minerals in roof, wall and floor rocks indicate that crystal settling was not an important mechanism. Likewise, the lack of fractionation of elements with different behavior indicate that diffusion and fluid-driven metasomatism played relatively minor roles. Compositional convection and/or compaction within the solidifying crystal mush boundary layer are likely the most important mechanisms. A correlation of low trapped liquid fractions (calculated from strongly incompatible elements) in floor rocks with high fractionation density (the density difference between the crystal framework and the liquid) indicate that compaction is the dominating process in expelling evolved liquid from the crystal mush layer. This is supported by high and variable trapped liquid contents in the roof rocks, where gravity

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.

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.

Reception and study of lunar surface material in inert gas medium. [considering laboratory vacuum receiving chamber

NASA Technical Reports Server (NTRS)

Surkov, Y. A.; Rudnitskiy, Y. M.; Glotov, V. A.

1974-01-01

The reception and study of lunar material returned by the Luna 16 space station is described. The layout of a vacuum receiving chamber for working with material in a helium atmosphere is examined along with the main operations involved in extracting the material from the ampule and drill.

Measurement of optical blurring in a turbulent cloud chamber

NASA Astrophysics Data System (ADS)

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

2016-10-01

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

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.

Closed-chamber transepidermal water loss measurement: microclimate, calibration and performance.

PubMed

Imhof, R E; De Jesus, M E P; Xiao, P; Ciortea, L I; Berg, E P

2009-04-01

The importance of transepidermal water loss (TEWL) as a measure of the skin barrier is well recognized. Currently, the open-chamber method is dominant, but it is increasingly challenged by newer closed-chamber technologies. Whilst there is familiarity with open-chamber characteristics, there is uncertainty about the capabilities of the challengers. The main issues are related to how microclimate affects TEWL measurements. The aim of this paper is to provide a framework for understanding the effects of microclimate on TEWL measurement. Part of the problem is that TEWL measurement is indirect. TEWL is the diffusion of condensed water through the stratum corneum (SC), whereas TEWL methods measure water vapour flux in the air above the SC. This vapour flux depends on (i) the rate of supply of water to the skin surface and (ii) the rate of evaporation of water from the skin surface. Rate (i) is a skin property (TEWL), rate (ii) is a microclimate property. The controlling rate for the combined process is the lower of the above two rates. Therefore, TEWL instruments measure TEWL only when TEWL is the rate-limiting process. Another problem is that SC barrier property and SC hydration are affected by the microclimate adjacent to the skin surface. This is discussed insofar as it affects the measurement of TEWL. The conclusion is that such changes occur on a timescale that is long compared with TEWL measurement times. An important aspect of TEWL measurement is calibration. We present an analysis of the traditional wet-cup method and a new droplet method that is traceable and has been independently verified by a standards laboratory. Finally, we review performance indicators of commercial closed-chamber instruments with reference to open-chamber instruments. The main findings are that TEWL readings correlate well, but there are significant differences in the other aspects of performance.

Gas and particle phase chemical characterization of photochemical smog in Beijing and Hong Kong

NASA Astrophysics Data System (ADS)

Hallquist, Mattias; Le Breton, Michael; Guo, Song; Zhen Yu, Jian; Hallquist, Åsa. M.; Pathak, Ravi K.; Liu, Qianyun; Wang, Yuchen; Li, Jinjian; Chan, Chak K.; Wang, Yujue; Zheng, Jing; Yang, Yudong; Lu, Keding; Wu, Zhijun; Hu, Min

2017-04-01

Secondary chemistry transforming primary pollutants is of high relevance for Chinese photochemical smog. In particular, formation of ozone (O3) and particulate matter (PM), including Secondary Organic Aerosols (SOA), are of major concern regarding impacts on health, climate and ecosystems. The atmospheric oxidation processes leading to SOA formation are complex and involves thousands of different compounds, both of biogenic and anthropogenic origin. Furthermore, for a thorough understanding both the gas and the particle phase need to be considered. As part of an intercollaborative project to assess the photochemical smog in China, two major field campaigns were arranged in 2016; in Changping, Bejing during springtime and at HKUST, Hong Kong during the autumn. Alongside with other advanced instrumentations, a Time of Flight Chemical Ionisation Mass Spectrometer (ToF CIMS) utilising the Filiter Inlet for Gases and AEROsols (FIGAERO) was used to chemically characterize the gas and the particle phase. This specific instrument applies soft ionization limiting the fragmentation and one can usually identify molecular composition of hundreds of different parent molecules. In both Beijing and Hong Kong the iodide ionization scheme was utilised, making it possible to specifically detect oxygenated compounds such as carboxylic acids, organic nitrates and sulphates as well as some inorganic compounds e.g. N2O5, ClNO2, and HONO. For numerous compounds significant levels were detected in both the gas and particle phase enabling evaluation of partitioning and gas-to-particle transformation and its relationship to atmospheric conditions and estimated vapour pressures. Furthermore, the detection of molecular markers such as levoglucosan, C6H5NO3, C10H16NSO7, C5H8SO7, C5H8O4 can support source apportionment and atmospheric process description. In order to further investigate atmospheric ageing/processing a portable laminar flow reactor (Go:PAM) was for selected periods utilized to

Spatial distribution of cloud droplets in a turbulent cloud-chamber flow

NASA Astrophysics Data System (ADS)

Jaczewski, A.; Malinowski, S. P.

2005-07-01

We present the results of a laboratory study of the spatial distribution of cloud droplets in a turbulent environment. An artificial, weakly turbulent cloud, consisting of droplets of diameter around 14 m, is observed in a laboratory chamber. Droplets on a vertical cross-section through the cloud interior are imaged using laser sheet photography. Images are digitized and numerically processed in order to retrieve droplet positions in a vertical plane. The spatial distribution of droplets in the range of scales, l, from 4 to 80 mm is characterized by: the clustering index CI(l), the volume averaged pair correlation function eta;(l) and a local density defined on a basis of correlation analysis. The results indicate that, even in weak turbulence in the chamber that is less intense and less intermittent than turbulence observed in clouds, droplets are not spread according to the Poisson distribution. The importance of this deviation from the Poisson distribution is unclear when looking at CI(l) and (l). The local density indicates that in small scales each droplet has, on average, more neighbours than expected from the average droplet concentration and gives a qualitative and intuitive measure of clustering.

Phoenix Lowered into Thermal Vacuum Chamber

NASA Technical Reports Server (NTRS)

2007-01-01

NASA's Phoenix Mars Lander was lowered into a thermal vacuum chamber at Lockheed Martin Space Systems, Denver, in December 2006.

The spacecraft was folded in its aeroshell and underwent environmental testing that simulated the extreme conditions the spacecraft will see during its nine-and-a-half-month cruse to Mars.

The Phoenix mission is led by Principal Investigator Peter H. Smith of the University of Arizona, Tucson, with project management at NASA's Jet Propulsion Laboratory and development partnership with Lockheed Martin Space Systems. International contributions for Phoenix are provided by the Canadian Space Agency, the University of Neuchatel (Switzerland), the University of Copenhagen, and the Max Planck Institute in Germany. JPL is a division of the California Institute of Technology in Pasadena.

Retrospective determination of the contamination in the HML's counting chambers.

PubMed

Kramer, Gary H; Hauck, Barry; Capello, Kevin; Phan, Quoc

2008-09-01

The original documentation surrounding the purchase of the Human Monitoring Laboratory's (HML) counting chambers clearly showed that the steel contained low levels of radioactivity, presumably as a result of A-bomb fallout or perhaps to the inadvertent mixing of radioactive sources with scrap steel. Monte Carlo simulations have been combined with experimental measurements to estimate the level of contamination in the steel of the HML's whole body counting chamber. A 24-h empty chamber background count showed the presence of 137Cs and 60Co. The estimated activity of 137Cs in the 51 tons of steel was 2.7 kBq in 2007 (51.3 microBq g(-1) steel) which would have been 8 kBq at the time of manufacture. The 60Co that was found in the background spectrum is postulated to be contained in the bed-frame. The estimated amount in 2007 was 5 Bq and its origin is likely to be contaminated scrap metal entering the steel production cycle sometime in the past. The estimated activities are 10 to 25 times higher than the estimated minimum detectable activity for this measurement. These amounts have no impact on the usefulness of the whole body counter.

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.

Metal explosion chambers: designing, manufacturing, application

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

The ribbon-cutting ceremony unveils the reactivated altitude chamber inside the O&C high bay

NASA Technical Reports Server (NTRS)

1999-01-01

At a ribbon-cutting ceremony inside the Operations and Checkout Building high bay, Sterling Walker, director of Engineering Development, introduces the project team members responsible for renovating an altitude chamber formerly used on the Apollo program. In addition, management, media and onlookers are present for the ceremony. Seated in the front row left are (left to right) Terry Smith, director of Engineering, Boeing Space Coast Operations; Steve Francois, director, Space Station and Shuttle Payloads; Jay Greene, International Space Station manager for Technical; and Roy Bridges, center director. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test.

Dark Matter Limits From a 2L C3F8 Filled Bubble Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, Alan Edward

2015-12-01

The PICO-2L C3F8 bubble chamber search forWeakly Interacting Massive Particle (WIMP) dark matter was operated in the SNOLAB underground laboratory at the same location as the previous CF3I lled COUPP-4kg detector. Neutron calibrations using photoneutron sources in C3F8 and CF3I lled calibration bubble chambers were performed to verify the sensitivity of these target uids to dark matter scattering. This data was combined with similar measurements using a low-energy neutron beam at the University of Montreal and in situ calibrations of the PICO-2L and COUPP-4kg detectors. C3F8 provides much greater sensitivity to WIMP-proton scattering than CF3I in bubble chamber detectors. PICO-2Lmore » searched for dark matter recoils with energy thresholds below 10 keV. Radiopurity assays of detector materials were performed and the expected neutron recoil background was evaluated to be 1.6+0:3« less

Degradation in the efficiency of glass Resistive Plate Chambers operated without external gas supply

NASA Astrophysics Data System (ADS)

Baesso, P.; Cussans, D.; Thomay, C.; Velthuis, J.; Burns, J.; Quillin, S.; Stapleton, M.; Steer, C.

2015-06-01

Resistive plate chambers (RPC) are particle detectors commonly used by the high energy physics community. Their normal operation requires a constant flow of gas mixture to prevent self-poisoning which reduces the chamber's capability to detect particles. We studied how quickly the efficiency of two RPCs drops when operated in sealed mode, i.e. without refreshing the gas mixture. The test aim is to determine how RPCs could be used as particle detectors in non-laboratory applications, such as those exploiting muon tomography for geological imaging or homeland security. The two sealed RPCs were operated in proportional mode for a period of more than three months, and their efficiencies were recorded continuously and analysed in 8-hours intervals. The results show that the efficiency drops on average by 0.79 ± 0.01 % every 24 hours of operation and returns close to the initial value after purging the old gas mixture and flushing the chambers with fresh gas.

Liquid rocket engine self-cooled combustion chambers

NASA Technical Reports Server (NTRS)

1977-01-01

Self-cooled combustion chambers are chambers in which the chamber wall temperature is controlled by methods other than fluid flow within the chamber wall supplied from an external source. In such chambers, adiabatic wall temperature may be controlled by use of upstream fluid components such as the injector or a film-coolant ring, or by internal flow of self-contained materials; e.g. pyrolysis gas flow in charring ablators, and the flow of infiltrated liquid metals in porous matrices. Five types of self-cooled chambers are considered in this monograph. The name identifying the chamber is indicative of the method (mechanism) by which the chamber is cooled, as follows: ablative; radiation cooled; internally regenerative (Interegen); heat sink; adiabatic wall. Except for the Interegen and heat sink concepts, each chamber type is discussed separately. A separate and final section of the monograph deals with heat transfer to the chamber wall and treats Stanton number evaluation, film cooling, and film-coolant injection techniques, since these subjects are common to all chamber types. Techniques for analysis of gas film cooling and liquid film cooling are presented.

Laboratory Measurements of Biomass Cook-stove Emissions Aged in an Oxidation Flow Reactor: Influence of Combustion and Aging Conditions on Aerosols

NASA Astrophysics Data System (ADS)

Grieshop, A. P.; Reece, S. M.; Sinha, A.; Wathore, R.

2016-12-01

Combustion in rudimentary and improved cook-stoves used by billions in developing countries can be a regionally dominant contributor to black carbon (BC), primary organic aerosols (POA) and precursors for secondary organic aerosol (SOA). Recent studies suggest that SOA formed during photo-oxidation of primary emissions from biomass burning may make important contribution to its atmospheric impacts. However, the extent to which stove type and operating conditions affect the amount, composition and characteristics of SOA formed from the aging of cookstoves emissions is still largely undetermined. Here we present results from experiments with a field portable oxidation flow reactor (F-OFR) designed to assess aging of cook-stove emissions in both laboratory and field settings. Laboratory tests results are used to compare the quantity and properties of fresh and aged emissions from a traditional open fire and twp alternative stove designs operated on the standard and alternate testing protocols. Diluted cookstove emissions were exposed to a range of oxidant concentrations in the F-OFR. Primary emissions were aged both on-line, to study the influence of combustion variability, and sampled from batched emissions in a smog chamber to examine different aging conditions. Data from real-time particle- and gas-phase instruments and integrated filter samples were collected up and down stream of the OFR. The properties of primary emissions vary strongly with stove type and combustion conditions (e.g. smoldering versus flaming). Experiments aging diluted biomass emissions from distinct phases of stove operation (smoldering and flaming) showed peak SOA production for both phases occurred between 3 and 6 equivalent days of aging with slightly greater production observed in flaming phase emissions. Changing combustion conditions had a stronger influence than aging on POA+SOA `emission factors'. Aerosol Chemical Speciation Monitor data show a substantial evolution of aerosol

Apollo Contour Rocket Nozzle in the Propulsion Systems Laboratory

NASA Image and Video Library

1964-07-21

Bill Harrison and Bud Meilander check the setup of an Apollo Contour rocket nozzle in the Propulsion Systems Laboratory at the National Aeronautics and Space Administration (NASA) Lewis Research Center. The Propulsion Systems Laboratory contained two 14-foot diameter test chambers that could simulate conditions found at very high altitudes. The facility was used in the 1960s to study complex rocket engines such as the Pratt and Whitney RL-10 and rocket components such as the Apollo Contour nozzle, seen here. Meilander oversaw the facility’s mechanics and the installation of test articles into the chambers. Harrison was head of the Supersonic Tunnels Branch in the Test Installations Division. Researchers sought to determine the impulse value of the storable propellant mix, classify and improve the internal engine performance, and compare the results with analytical tools. A special setup was installed in the chamber that included a device to measure the thrust load and a calibration stand. Both cylindrical and conical combustion chambers were examined with the conical large area ratio nozzles. In addition, two contour nozzles were tested, one based on the Apollo Service Propulsion System and the other on the Air Force’s Titan transtage engine. Three types of injectors were investigated, including a Lewis-designed model that produced 98-percent efficiency. It was determined that combustion instability did not affect the nozzle performance. Although much valuable information was obtained during the tests, attempts to improve the engine performance were not successful.

Development of a versatile user-friendly IBA experimental chamber

NASA Astrophysics Data System (ADS)

Kakuee, Omidreza; Fathollahi, Vahid; Lamehi-Rachti, Mohammad

2016-03-01

Reliable performance of the Ion Beam Analysis (IBA) techniques is based on the accurate geometry of the experimental setup, employment of the reliable nuclear data and implementation of dedicated analysis software for each of the IBA techniques. It has already been shown that geometrical imperfections lead to significant uncertainties in quantifications of IBA measurements. To minimize these uncertainties, a user-friendly experimental chamber with a heuristic sample positioning system for IBA analysis was recently developed in the Van de Graaff laboratory in Tehran. This system enhances IBA capabilities and in particular Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA) techniques. The newly developed sample manipulator provides the possibility of both controlling the tilt angle of the sample and analyzing samples with different thicknesses. Moreover, a reasonable number of samples can be loaded in the sample wheel. A comparison of the measured cross section data of the 16O(d,p1)17O reaction with the data reported in the literature confirms the performance and capability of the newly developed experimental chamber.

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.

Interstellar and Planetary Analogs in the Laboratory

NASA Technical Reports Server (NTRS)

Salama, Farid

2013-01-01

We present and discuss the unique capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to investigate the interaction of ionizing radiation (UV, charged particles) with molecular species (neutral molecules, radicals and ions) and carbonaceous grains in the Solar System and in the Interstellar Medium (ISM). COSmIC stands for Cosmic Simulation Chamber, a laboratory chamber where interstellar and planetary analogs are generated, processed and analyzed. It is composed of a pulsed discharge nozzle (PDN) expansion that generates a free jet supersonic expansion in a plasma cavity coupled to two ultrahigh-sensitivity, complementary in situ diagnostics: a cavity ring down spectroscopy (CRDS) system for photonic detection and a Reflectron time-of-flight mass spectrometer (ReTOF-MS) for mass detection. This setup allows the study of molecules, ions and solids under the low temperature and high vacuum conditions that are required to simulate some interstellar, circumstellar and planetary physical environments providing new fundamental insights on the molecular level into the processes that are critical to the chemistry in the ISM, circumstellar and planet forming regions, and on icy objects in the Solar System. Recent laboratory results that were obtained using COSmIC will be discussed, in particular the progress that have been achieved in monitoring in the laboratory the formation of solid particles from their gas-phase molecular precursors in environments as varied as circumstellar outflow and planetary atmospheres.

David Florida Laboratory: Support for mobile satellite communications

NASA Technical Reports Server (NTRS)

Dumoulin, Jean-Guy; Mamen, Rolf

1995-01-01

The comprehensive integration and environmental (including RF) test facilities of the Canadian Space Agency's David Florida Laboratory (CSA)(DFL) were used extensively for the MSAT Program. Following a description of the facilities, the paper outlines their application to the qualification of the two MSAT satellites following an overview of the test plan. Particular emphasis is given to passive intermodulation measurement (PIM) demands, which for the MSAT satellites, contributed to the need to extend the anechoic chamber. The extended chamber was also used for an EMC test and SAR signature test of the RADARSAT satellite. The DFL's facilities are being used for additional aspects of mobile satellite communications. One shielded anechoic Extra High Frequency (EHF) chamber and associated test equipment are employed predominantly for measuring the performance of the IRIDIUM satellites' Engineering Model Gateway Moveable Antennas (EM)(GMA). Other chambers are used for testing aeronautical antennas on behalf of Inmarsat. Still others combine thermal and PIM testing. The paper concludes with a review of the test requirements of evolving satcom missions such as Inmarsat Aero-1.

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

NASA Astrophysics Data System (ADS)

Amin, R.; Izadi, H.; Quémerais, B.

2015-05-01

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

Small-Chamber Measurements of Chemical-Specific Emission Factors for Drywall

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maddalena, Randy; Russell, Marion; Apte, Michael G.

2010-06-01

Imported drywall installed in U.S. homes is suspected of being a source of odorous and potentially corrosive indoor pollutants. To support an investigation of those building materials by the Consumer Products Safety Commission (CPSC), Lawrence Berkeley National Laboratory (LBNL) measured chemical-specific emission factors for 30 samples of drywall materials. Emission factors are reported for 75 chemicals and 30 different drywall samples encompassing both domestic and imported stock and incorporating natural, synthetic, or mixed gypsum core material. CPSC supplied all drywall materials. First the drywall samples were isolated and conditioned in dedicated chambers, then they were transferred to small chambers wheremore » emission testing was performed. Four sampling and analysis methods were utilized to assess (1) volatile organic compounds, (2) low molecular weight carbonyls, (3) volatile sulfur compounds, and (4) reactive sulfur gases. LBNL developed a new method that combines the use of solid phase microextraction (SPME) with small emission chambers to measure the reactive sulfur gases, then extended that technique to measure the full suite of volatile sulfur compounds. The testing procedure and analysis methods are described in detail herein. Emission factors were measured under a single set of controlled environmental conditions. The results are compared graphically for each method and in detailed tables for use in estimating indoor exposure concentrations.« less

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.

The Southwest Research Institute ultraviolet reflectance chamber (SwURC): a far ultraviolet reflectometer

NASA Astrophysics Data System (ADS)

Winters, Gregory S.; Retherford, Kurt D.; Davis, Michael W.; Escobedo, Stephen M.; Bassett, Eric C.; Patrick, Edward L.; Nagengast, Maggie E.; Fairbanks, Matthew H.; Miles, Paul F.; Parker, Joel W.; Gladstone, G. Randall; Slater, David C.; Stern, S. Alan

2012-10-01

We designed and assembled a highly capable UV reflectometer chamber and data acquisition system to provide bidirectional scattering data of various surfaces and materials. This chamber was initially conceived to create laboratory-based UV reflectance measurements of water frost on lunar soil/regolith simulants, to support interpretation of UV reflectance data from the Lyman Alpha Mapping Project ("LAMP") instrument on-board the NASA Lunar Reconnaissance Orbiter spacecraft. A deuterium lamp illuminates surfaces and materials at a fixed 45° incident beam angle over the 115 to 200 nm range via a monochromator, while a photomultiplier tube detector is scanned to cover emission angles -85° to +85° (with a gap from -60° to -30°, due to the detector blocking the incident beam). Liquid nitrogen cools the material/sample mount when desired. The chamber can be configured to test a wide range of samples and materials using sample trays and holders. Test surfaces to date include aluminum mirrors, water ice, reflectance standards, and frozen mixtures of water and lunar soil/regolith stimulant. Future UV measurements planned include Apollo lunar samples, meteorite samples, other ices, minerals, and optical surfaces. Since this chamber may well be able to provide useful research data for groups outside Southwest Research Institute, we plan to take requests from and collaborate with others in the UV and surface reflection research community.

DECISION-MAKING SPARK CHAMBERS,

DTIC Science & Technology

of scattering of a particle and coplanarity of two particles. Decision - making spark chambers are used to trigger an optical spark chamber of two...the position of a spark and the separation of two sparks. Many other kinds of spatial decisions can be made with these devices such as the recognition

First In Vivo Measurements of Methane Emissions from Ruminant Livestock Enteric Fermentation in Mexico Using Respiration Chambers

NASA Astrophysics Data System (ADS)

Castelan-Ortega, O. A.; Ku-Vera, J. C.; Molina, L. T.; Pedraza-Beltrán, P. E.; Canul-Solis, J. R.; Piñeiro-Vázquez, A.; Hernández-Pineda, G.; Benaouda, M.

2015-12-01

Until recently there were no facilities in Mexico to measure in vivo methane (CH4) emission by livestock. Inventories were calculated using emission factors from the IPCC, so the uncertainty in calculation is high. In 2014 the first laboratory equipped to measure CH4 started operations at the Universidad Autónoma de Yucatán. The second laboratory was built at the Universidad Autónoma del Estado de México and it began operations in June 2015. The first laboratory consists of two open-circuit respiration chambers, which are currently used to measure CH4 emissions by cattle in Mexico's tropical regions. Chamber dimensions are: 3.0 x 2.14 x 1.44 m (DxHxW). Air exiting the chambers is drawn by a mass flowmeter (Flowkit 500) at a rate of 500 L/min. The air sample is passed through a multiplexer and then through a chemical desiccant before entering the methane infrared analyzer (MA-10). All the instruments were fabricated by Sable Systems International, Las Vegas, USA. The average CH4 emission factor for Nelore bulls of 350 kg live weight fed with a tropical grass was 117.3 L/day and it increased to 198.6 L/day when 3 kg of concentrate feed were supplemented. For adult crossbred cows also fed with a tropical grass CH4 emission ranged from 92.7 to 137.3 L/day. The second laboratory consist of a respiration chamber of the head box type. It consists of a head box of 1.05 x 0.8 x 1.80 m (WxDxH) made of 3.5 x 3.5 cm stainless steel angle, and on the bottom, top, sides, back and front of the head box, 0.6 cm clear acrylic sheeting was used to provide comfortable vision to the animal, and a metabolic cage of 1.08 x 2.92 x 1.8 m (WxDxH) made of iron tubes with steel sheeting floor adapted for feces and urine collection. The methane analyzer and the mass flowmeter were of the same model as in the first laboratory. Once calibrated, in vivo measurements were performed using high yielding adult Holstein cows with an average live weight of 573 ±71 kg and milk yield of 30kg

SUMO Chamber Conditions

DOE Data Explorer

Sevanto, Sanna [Los Alamos National Laboratory; Powers, Heath [Los Alamos National Laboratory; Dickman, Turin L. [Los Alamos National Laboratory; Collins, Adam [Los Alamos National Laboratory; Grossiord, Charlotte [Swiss Federal Institute for Forest Snow and Landscape Research; Adams, Henry [Oklahoma State University; Borrego, Isaac [USGS Southwest Biological Science Center; McDowell, Nate [Pacific Northwest National Laboratory (PNNL); Stockton, Elizabeth [University of New Mexico; Ryan, Max [Los Alamos National Laboratory; Slentz, Matthew [Mohle Adams; Briggs, Sam [Fossil Creek Nursery; McBranch, Natalie [Los Alamos National Laboratory; Morgan, Bryn [Los Alamos National Laboratory

2018-01-01

The Los Alamos Survival–Mortality experiment (SUMO) is located on Frijoles Mesa near Los Alamos, New Mexico, USA, at an elevation of 2150 m. This was a tree manipulation study that investigated the relative impacts of drought and warming on plant function and reveals how trees adapt to drought and heat in semi-arid regions. The study factored the role of tree hydraulic acclimation to both precipitation and temperature and separated their effects.The experiment is located in a pinon-juniper woodland near the ponderosa pine (Pinus ponderosa) forest ecotone. Chamber conditions (temperature, relative humidity, vapor pressure deficit) for SUMO Open Top Chambers (OTCs) used to control air temperatures surrounding heated and control chamber trees. See SUMO Target Tree Information data package (doi:10.15485/1440544) for additional information. Data released by Los Alamos National Lab for public use under LA-UR-18-23656.

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.

Usefulness of hemocytometer as a counting chamber in a computer assisted sperm analyzer (CASA)

USGS Publications Warehouse

Eljarah, A.; Chandler, J.; Jenkins, J.A.; Chenevert, J.; Alcanal, A.

2013-01-01

Several methods are used to determine sperm cell concentration, such as the haemocytometer, spectrophotometer, electronic cell counter and computer-assisted semen analysers (CASA). The utility of CASA systems has been limited due to the lack of characterization of individual systems and the absence of standardization among laboratories. The aims of this study were to: 1) validate and establish setup conditions for the CASA system utilizing the haemocytometer as a counting chamber, and 2) compare the different methods used for the determination of sperm cell concentration in bull semen. Two ejaculates were collected and the sperm cell concentration was determined using spectrophotometer and haemocytometer. For the Hamilton-Thorn method, the haemocytometer was used as a counting chamber. Sperm concentration was determined three times per ejaculate samples. A difference (P 0.05) or between the haemocytometer count and the spectrophotometer. Based on the results of this study, we concluded that the haemocytometer can be used in computerized semen analysis systems as a substitute for the commercially available disposable counting chambers, therefore avoiding disadvantageous high costs and slower procedures.

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.

Use of a Remote Car Starter in Relation to Smog and Climate Change Perceptions: A Population Survey in Québec (Canada)

PubMed Central

Bélanger, Diane; Gosselin, Pierre; Valois, Pierre; Germain, Stéphane; Abdous, Belkacem

2009-01-01

Remote car starters encourage motorists to warm up their vehicles by idling the motor – thus increasing atmospheric pollutants, including several greenhouse gas (GHG) with impacts on public health. This study about climate change (CC) adaptation and mitigation actions examined perceptions on air pollution and climate change and individual characteristics associated with the use of a remote car starter. A telephone survey (n = 2,570; response rate: 70%) of adults living in Québec (Canada) measured the respondents’ beliefs and current behaviours regarding CC. Approximately 32.9% (daily car users) and 27.4% (occasional users) reported using a remote car starter during winter. The odds of the use of a remote car starter was higher in the less densely populated central (OR: 1.5) and peripheral regions (OR: 2.7) compared to the urban centers (ex. Montreal). The odds was also higher in population with a mother tongue other than English or French (OR: 2.6) and francophones than anglophones (OR: 2.1), women than men (OR: 1.5), daily drivers than occasional ones (OR: 1.2), and respondents who at least sometimes consulted temperature/humidity reports than those who consulted them less often (OR: 1.5). In multivariate analysis, the perception of living in a region susceptible to winter smog, being aware of smog warnings, or the belief in the human contribution to CC did not significantly influence the use of a remote car starter. The use of remote car starters encourages idling which produces increased atmospheric pollution and GHG production and it should be more efficiently and vigorously managed by various activities. A five-minute daily reduction in idling is equivalent to reducing the total car emissions by 1.8%. This would constitute a “no-regrets” approach to CC as it can simultaneously reduce GHG, air pollution and their health impacts. PMID:19440410

Use of a remote car starter in relation to smog and climate change perceptions: a population survey in Québec (Canada).

PubMed

Bélanger, Diane; Gosselin, Pierre; Valois, Pierre; Germain, Stéphane; Abdous, Belkacem

2009-02-01

Remote car starters encourage motorists to warm up their vehicles by idling the motor--thus increasing atmospheric pollutants, including several greenhouse gas (GHG) with impacts on public health. This study about climate change (CC) adaptation and mitigation actions examined perceptions on air pollution and climate change and individual characteristics associated with the use of a remote car starter. A telephone survey (n = 2,570; response rate: 70%) of adults living in Québec (Canada) measured the respondents' beliefs and current behaviours regarding CC. Approximately 32.9% (daily car users) and 27.4% (occasional users) reported using a remote car starter during winter. The odds of the use of a remote car starter was higher in the less densely populated central (OR: 1.5) and peripheral regions (OR: 2.7) compared to the urban centers (ex. Montreal). The odds was also higher in population with a mother tongue other than English or French (OR: 2.6) and francophones than anglophones (OR: 2.1), women than men (OR: 1.5), daily drivers than occasional ones (OR: 1.2), and respondents who at least sometimes consulted temperature/humidity reports than those who consulted them less often (OR: 1.5). In multivariate analysis, the perception of living in a region susceptible to winter smog, being aware of smog warnings, or the belief in the human contribution to CC did not significantly influence the use of a remote car starter. The use of remote car starters encourages idling which produces increased atmospheric pollution and GHG production and it should be more efficiently and vigorously managed by various activities. A five-minute daily reduction in idling is equivalent to reducing the total car emissions by 1.8%. This would constitute a "no-regrets" approach to CC as it can simultaneously reduce GHG, air pollution and their health impacts.

Secondary organic aerosol formation in biomass-burning plumes: theoretical analysis of lab studies and ambient plumes

NASA Astrophysics Data System (ADS)

Bian, Qijing; Jathar, Shantanu H.; Kodros, John K.; Barsanti, Kelley C.; Hatch, Lindsay E.; May, Andrew A.; Kreidenweis, Sonia M.; Pierce, Jeffrey R.

2017-04-01

Secondary organic aerosol (SOA) has been shown to form in biomass-burning emissions in laboratory and field studies. However, there is significant variability among studies in mass enhancement, which could be due to differences in fuels, fire conditions, dilution, and/or limitations of laboratory experiments and observations. This study focuses on understanding processes affecting biomass-burning SOA formation in laboratory smog-chamber experiments and in ambient plumes. Vapor wall losses have been demonstrated to be an important factor that can suppress SOA formation in laboratory studies of traditional SOA precursors; however, impacts of vapor wall losses on biomass-burning SOA have not yet been investigated. We use an aerosol-microphysical model that includes representations of volatility and oxidation chemistry to estimate the influence of vapor wall loss on SOA formation observed in the FLAME III smog-chamber studies. Our simulations with base-case assumptions for chemistry and wall loss predict a mean OA mass enhancement (the ratio of final to initial OA mass, corrected for particle-phase wall losses) of 1.8 across all experiments when vapor wall losses are modeled, roughly matching the mean observed enhancement during FLAME III. The mean OA enhancement increases to over 3 when vapor wall losses are turned off, implying that vapor wall losses reduce the apparent SOA formation. We find that this decrease in the apparent SOA formation due to vapor wall losses is robust across the ranges of uncertainties in the key model assumptions for wall-loss and mass-transfer coefficients and chemical mechanisms.We then apply similar assumptions regarding SOA formation chemistry and physics to smoke emitted into the atmosphere. In ambient plumes, the plume dilution rate impacts the organic partitioning between the gas and particle phases, which may impact the potential for SOA to form as well as the rate of SOA formation. We add Gaussian dispersion to our aerosol

Secondary organic aerosol formation in biomass-burning plumes: theoretical analysis of lab studies and ambient plumes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bian, Qijing; Jathar, Shantanu H.; Kodros, John K.

Secondary organic aerosol (SOA) has been shown to form in biomass-burning emissions in laboratory and field studies. However, there is significant variability among studies in mass enhancement, which could be due to differences in fuels, fire conditions, dilution, and/or limitations of laboratory experiments and observations. This study focuses on understanding processes affecting biomass-burning SOA formation in laboratory smog-chamber experiments and in ambient plumes. Vapor wall losses have been demonstrated to be an important factor that can suppress SOA formation in laboratory studies of traditional SOA precursors; however, impacts of vapor wall losses on biomass-burning SOA have not yet been investigated.more » We use an aerosol-microphysical model that includes representations of volatility and oxidation chemistry to estimate the influence of vapor wall loss on SOA formation observed in the FLAME III smog-chamber studies. Our simulations with base-case assumptions for chemistry and wall loss predict a mean OA mass enhancement (the ratio of final to initial OA mass, corrected for particle-phase wall losses) of 1.8 across all experiments when vapor wall losses are modeled, roughly matching the mean observed enhancement during FLAME III. The mean OA enhancement increases to over 3 when vapor wall losses are turned off, implying that vapor wall losses reduce the apparent SOA formation. We find that this decrease in the apparent SOA formation due to vapor wall losses is robust across the ranges of uncertainties in the key model assumptions for wall-loss and mass-transfer coefficients and chemical mechanisms. We then apply similar assumptions regarding SOA formation chemistry and physics to smoke emitted into the atmosphere. In ambient plumes, the plume dilution rate impacts the organic partitioning between the gas and particle phases, which may impact the potential for SOA to form as well as the rate of SOA formation. We add Gaussian dispersion to our aerosol

Secondary organic aerosol formation in biomass-burning plumes: theoretical analysis of lab studies and ambient plumes

DOE PAGES

Bian, Qijing; Jathar, Shantanu H.; Kodros, John K.; ...

2017-04-28

Secondary organic aerosol (SOA) has been shown to form in biomass-burning emissions in laboratory and field studies. However, there is significant variability among studies in mass enhancement, which could be due to differences in fuels, fire conditions, dilution, and/or limitations of laboratory experiments and observations. This study focuses on understanding processes affecting biomass-burning SOA formation in laboratory smog-chamber experiments and in ambient plumes. Vapor wall losses have been demonstrated to be an important factor that can suppress SOA formation in laboratory studies of traditional SOA precursors; however, impacts of vapor wall losses on biomass-burning SOA have not yet been investigated.more » We use an aerosol-microphysical model that includes representations of volatility and oxidation chemistry to estimate the influence of vapor wall loss on SOA formation observed in the FLAME III smog-chamber studies. Our simulations with base-case assumptions for chemistry and wall loss predict a mean OA mass enhancement (the ratio of final to initial OA mass, corrected for particle-phase wall losses) of 1.8 across all experiments when vapor wall losses are modeled, roughly matching the mean observed enhancement during FLAME III. The mean OA enhancement increases to over 3 when vapor wall losses are turned off, implying that vapor wall losses reduce the apparent SOA formation. We find that this decrease in the apparent SOA formation due to vapor wall losses is robust across the ranges of uncertainties in the key model assumptions for wall-loss and mass-transfer coefficients and chemical mechanisms. We then apply similar assumptions regarding SOA formation chemistry and physics to smoke emitted into the atmosphere. In ambient plumes, the plume dilution rate impacts the organic partitioning between the gas and particle phases, which may impact the potential for SOA to form as well as the rate of SOA formation. We add Gaussian dispersion to our aerosol

Monitoring the Gas Composition of the NIFFTE Time Projection Chamber

NASA Astrophysics Data System (ADS)

Towell, Travis; Travis Towell Collaboration

2017-09-01

The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) at Los Alamos National Laboratory(LANL) is using a Time Projection Chamber (TPC) to measure with high precision the cross section ratio of U238 to P239. When the neutron beam hits a target, it may emit fission fragments. As the fission fragments travels through the chamber, it ionizes the gas it passes through. Based on the time it takes for the ions to drift to the pad planes and the hit location of the ions, the path of fission fragments can be determined. Knowing the composition of the gas mixture is vital to accurately reconstruct the data. A Binary Gas Analyzer (BGA) is used to measure the gas composition. To confirm the accuracy of the BGA, varying amounts of nitrogen and carbon dioxide were flowed through a test gas system. Several tests were performed to validate that the BGA for our gas system is working properly. This poster will describe the test gas system setup, tests of the BGA, and elaborate on the main goals of the NIFFTE experiment.

SMOG-CHAMBER TOXICOLOGY BETTER ESTIMATES THE TRUE TOXIC POTENTIAL OF ATMOSPHERIC MIXTURES

EPA Science Inventory

The chemistry of hazardous air pollutants (HAPs) have been studied for many years, yet little is known about how these chemicals, once interacted with urban atmospheres, affect healthy and susceptible individuals. The toxic potential of these very reactive compounds once they int...

SSME Main Combustion Chamber (MCC) hot oil dewaxing

NASA Technical Reports Server (NTRS)

Akpati, Anthony U.

1995-01-01

In an attempt to comply with the changing environmental regulations, a process was developed for the replacement of perchloroethylene in the dewaxing of the Space Shuttle Main Engine (SSME) Main Combustion Chamber (MCC) and other associated hardware filled with the Rigidax (R) casting compound. Rigidax (R) is a hard blue-dyed, calcium carbonate filled thermoplastic casting compound (melting point 77 C) that is melted and poured into hardware cavities to prevent contamination during material removal processes, i.e. machining, grinding, drilling, and deburring. Additionally, it serves as a maskant for designated areas during electroforming processes. Laboratory testing was conducted to evaluate seven alternate fluids for the replacement of perchloroethylene in the dewaxing process. Based upon successful laboratory results, a mineral oil was selected for testing on actual hardware. The final process developed involves simultaneous immersion and flushing of the MCC channels using a distinct eight stage process. A nonvolatile hydrocarbon analysis of a solvent flush sample is performed to determine the hardware cleanliness for comparison to the previous perchloroethylene dewaxing process.

SSME Main Combustion Chamber (MCC) 'Hot Oil' Dewaxing

NASA Technical Reports Server (NTRS)

Akpati, Anthony U.

1994-01-01

In an attempt to comply with the changing environmental regulations, a process was developed for the replacement of perchloroethylene in the dewaxing of the Space Shuttle Main Engine (SSME) Main Combustion Chamber (MCC) and other associated hardware filled with the Rigidax(registered mark) casting compound. Rigidax(registered mark) is a hard blue-dyed, calcium carbonate filled thermoplastic casting compound (melting point 77 C) that is melted and poured into hardware cavities to prevent contamination during material removal processes, i.e. machining, grinding, drilling, and deburring. Additionally, it serves as a maskant for designated areas during electroforming processes. Laboratory testing was conducted to evaluate seven alternate fluids for the replacement of perchloroethylene in the dewaxing process. Based upon successful laboratory results, a mineral oil was selected for testing on actual hardware. The final process developed involves simultaneous immersion and flushing of the MCC channels using a distinct eight stage process. A nonvolatile hydrocarbon analysis of a solvent flush sample is performed to determine the hardware cleanliness for comparison to the previous perchloroethylene dewaxing process.

NOTE: Calibration of low-energy electron beams from a mobile linear accelerator with plane-parallel chambers using both TG-51 and TG-21 protocols

NASA Astrophysics Data System (ADS)

Beddar, A. S.; Tailor, R. C.

2004-04-01

A new approach to intraoperative radiation therapy led to the development of mobile linear electron accelerators that provide lower electron energy beams than the usual conventional accelerators commonly encountered in radiotherapy. Such mobile electron accelerators produce electron beams that have nominal energies of 4, 6, 9 and 12 MeV. This work compares the absorbed dose output calibrations using both the AAPM TG-51 and TG-21 dose calibration protocols for two types of ion chambers: a plane-parallel (PP) ionization chamber and a cylindrical ionization chamber. Our results indicate that the use of a 'Markus' PP chamber causes 2 3% overestimation in dose output determination if accredited dosimetry-calibration laboratory based chamber factors \\big(N_{{\\rm D},{\\rm w}}^{{}^{60}{\\rm Co}}, N_x\\big) are used. However, if the ionization chamber factors are derived using a cross-comparison at a high-energy electron beam, then a good agreement is obtained (within 1%) with a calibrated cylindrical chamber over the entire energy range down to 4 MeV. Furthermore, even though the TG-51 does not recommend using cylindrical chambers at the low energies, our results show that the cylindrical chamber has a good agreement with the PP chamber not only at 6 MeV but also down to 4 MeV electron beams.

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.

Unspeciated organic emissions from combustion sources and their influence on the secondary organic aerosol budget in the United States

PubMed Central

Jathar, Shantanu H.; Gordon, Timothy D.; Hennigan, Christopher J.; Pye, Havala O. T.; Pouliot, George; Adams, Peter J.; Donahue, Neil M.; Robinson, Allen L.

2014-01-01

Secondary organic aerosol (SOA) formed from the atmospheric oxidation of nonmethane organic gases (NMOG) is a major contributor to atmospheric aerosol mass. Emissions and smog chamber experiments were performed to investigate SOA formation from gasoline vehicles, diesel vehicles, and biomass burning. About 10–20% of NMOG emissions from these major combustion sources are not routinely speciated and therefore are currently misclassified in emission inventories and chemical transport models. The smog chamber data demonstrate that this misclassification biases model predictions of SOA production low because the unspeciated NMOG produce more SOA per unit mass than the speciated NMOG. We present new source-specific SOA yield parameterizations for these unspeciated emissions. These parameterizations and associated source profiles are designed for implementation in chemical transport models. Box model calculations using these new parameterizations predict that NMOG emissions from the top six combustion sources form 0.7 Tg y−1 of first-generation SOA in the United States, almost 90% of which is from biomass burning and gasoline vehicles. About 85% of this SOA comes from unspeciated NMOG, demonstrating that chemical transport models need improved treatment of combustion emissions to accurately predict ambient SOA concentrations. PMID:25002466

Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

2016-01-01

NARloy-Z alloy (Cu-3 percent, Ag-0.5 percent, Zr) is a state of the art alloy currently used for fabricating rocket engine combustion chamber liners. Research conducted at NASA-MSFC and Penn State – Applied Research Laboratory has shown that thermal conductivity of NARloy-Z can be increased significantly by adding diamonds to form a composite (NARloy-Z-D). NARloy-Z-D is also lighter than NARloy-Z. These attributes make this advanced composite material an ideal candidate for fabricating combustion chamber liner for an advanced rocket engine. Increased thermal conductivity will directly translate into increased turbopump power and increased chamber pressure for improved thrust and specific impulse. This paper describes the process development for fabricating a subscale high thermal conductivity NARloy-Z-D combustion chamber liner using Field Assisted Sintering Technology (FAST). The FAST process uses a mixture of NARloy-Z and diamond powders which is sintered under pressure at elevated temperatures. Several challenges were encountered, i.e., segregation of diamonds, machining the super hard NARloy-Z-D composite, net shape fabrication and nondestructive examination. The paper describes how these challenges were addressed. Diamonds coated with copper (CuD) appear to give the best results. A near net shape subscale combustion chamber liner is being fabricated by diffusion bonding cylindrical rings of NARloy-Z-CuD using the FAST process.

A study to assess the long-term stability of the ionization chamber reference system in the LNMRI

NASA Astrophysics Data System (ADS)

Trindade Filho, O. L.; Conceição, D. A.; da Silva, C. J.; Delgado, J. U.; de Oliveira, A. E.; Iwahara, A.; Tauhata, L.

2018-03-01

Ionization chambers are used as secondary standard in order to maintain the calibration factors of radionuclides in the activity measurements in metrology laboratories. Used as radionuclide calibrator in nuclear medicine clinics to control dose in patients, its long-term performance is not evaluated systematically. A methodology for long-term evaluation for its stability is monitored and checked. Historical data produced monthly of 2012 until 2017, by an ionization chamber, electrometer and 226Ra, were analyzed via control chart, aiming to follow the long-term performance. Monitoring systematic errors were consistent within the limits of control, demonstrating the quality of measurements in compliance with ISO17025.

Laboratory development and testing of spacecraft diagnostics

NASA Astrophysics Data System (ADS)

Amatucci, William; Tejero, Erik; Blackwell, Dave; Walker, Dave; Gatling, George; Enloe, Lon; Gillman, Eric

2017-10-01

The Naval Research Laboratory's Space Chamber experiment is a large-scale laboratory device dedicated to the creation of large-volume plasmas with parameters scaled to realistic space plasmas. Such devices make valuable contributions to the investigation of space plasma phenomena under controlled, reproducible conditions, allowing for the validation of theoretical models being applied to space data. However, in addition to investigations such as plasma wave and instability studies, such devices can also make valuable contributions to the development and testing of space plasma diagnostics. One example is the plasma impedance probe developed at NRL. Originally developed as a laboratory diagnostic, the sensor has now been flown on a sounding rocket, is included on a CubeSat experiment, and will be included on the DoD Space Test Program's STP-H6 experiment on the International Space Station. In this talk, we will describe how the laboratory simulation of space plasmas made this development path possible. Work sponsored by the US Naval Research Laboratory Base Program.

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…

Global scale variability of the mineral dust longwave refractive index from laboratory chamber experiments: re‒evaluation of its direct radiative effect

NASA Astrophysics Data System (ADS)

Di Biagio, C.; Formenti, P.; Balkanski, Y.; Caponi, L.; Cazaunau, M.; Pangui, E.; Journet, E.; Nowak, S.; Caquineau, S.; Andreae, M. O.; Kandler, K.; Saeed, T.; Piketh, S.; Seibert, D.; Williams, E.; Boucher, O.; Doussin, J. F.

2017-12-01

New measurements of the longwave complex refractive index (LW CRI) of mineral dust and its global variability were obtained in situ in the 4.2 m3CESAM simulation chamber at LISA (Laboratoire Interuniversitaire des Systemes Atmospheriques) in Créteil, France. Aerosols generated by mechanical shaking from nineteen natural soils with contrasted mineralogical composition were suspended in the chamber, where their LW extinction spectra (2-16 μm), size distribution, and mineralogical composition were measured. The CRI of the dust aerosol was obtained by optical calculations based upon the measured extinction spectrum and size distribution. Laboratory results indicate that the LW refractive index of dust strongly varies with the source region of emission in link with the changes of its mineralogy. In the 2-16 μm spectral range, the imaginary refractive index (k) is between 0.001 and 0.92, and the real part (n) in the range 0.84-1.94. The strength of the dust absorption at 7 and 11.4 µm depends on the amount of calcite within the samples, while the absorption between 8 and 14 µm is determined by the relative abundance of quartz and clays. A linear relationship between the magnitude of k at 7, 9.2, and 11.4 µm and the mass concentration of calcite and quartz absorbing at these wavelengths was found, which suggests that predictive rules could be established to estimate the LW refractive index of dust in specific bands based on an assumed or predicted mineralogical composition. Our observations also suggest that the LW CRI of dust does not change as a result of the loss of coarse particles by gravitational settling, so that a constant value can be assumed close to sources and following transport. This unprecedented dataset of refractive indices was used as input into the LMDZORINCA model coupled with the RRTM radiative transfer module in order to re‒evaluate the direct dust LW radiative effect. This represents a first attempt to use regional‒dependent values of the

Hyperbaric and hypobaric chamber fires: a 73-year analysis.

PubMed

Sheffield, P J; Desautels, D A

1997-09-01

Fire can be catastrophic in the confined space of a hyperbaric chamber. From 1923 to 1996, 77 human fatalities occurred in 35 hyperbaric chamber fires, three human fatalities in a pressurized Apollo Command Module, and two human fatalities in three hypobaric chamber fires reported in Asia, Europe, and North America. Two fires occurred in diving bells, eight occurred in recompression (or decompression) chambers, and 25 occurred in clinical hyperbaric chambers. No fire fatalities were reported in the clinical hyperbaric chambers of North America. Chamber fires before 1980 were principally caused by electrical ignition. Since 1980, chamber fires have been primarily caused by prohibited sources of ignition that an occupant carried inside the chamber. Each fatal chamber fire has occurred in an enriched oxygen atmosphere (> 28% oxygen) and in the presence of abundant burnable material. Chambers pressurized with air (< 23.5% oxygen) had the only survivors. Information in this report was obtained from the literature and from the Undersea and Hyperbaric Medical Society's Chamber Experience and Mishap Database. This epidemiologic review focuses on information learned from critical analyses of chamber fires and how it can be applied to safe operation of hypobaric and hyperbaric chambers.

A new field-laboratory methodology for assessing human response to noise

NASA Technical Reports Server (NTRS)

Borsky, P. N.

1973-01-01

Gross measures of community annoyance with intrusive noises have been made in a number of real environment surveys which indicate that aircraft noise may have to be reduced 30-40 EPNdb before it will generally be considered acceptable. Interview studies, however, cannot provide the precise information which is needed by noise abatement engineers of the variable human response to different types and degrees of noise exposure. A new methodological field-survey approach has been developed to provide such information. The integrated attitudes and experiences of a random sample of subjects in the real environment are obtained by a prior field survey. Then these subjects record their more precise responses to controlled noise exposures in a new realistic laboratory. The laboratory is a sound chamber furnished as a typical living room (18 ft x 14 ft) and subjects watch a color TV program while they judge simulated aircraft flyovers that occur at controlled levels and intervals. Methodological experiments indicate that subjects in the laboratory have the sensation that the airplanes are actually moving overhead across the ceiling of the chamber. It was also determined that annoyance judgments in the laboratory stabilize after three flyovers are heard prior to a judgment of annoyance.

An inter-laboratory comparison study of the ANSI/BIFMA standard test method M7.1 for furniture

EPA Science Inventory

Five laboratories using five different test chambers participated in the study to quantify within- and between-laboratory variability in the measurement of emissions of volatile organic compounds (VOCs) from new commercial furniture test items following ANSI/BIFMA M7.1. Test item...

High pressure reaction cell and transfer mechanism for ultrahigh vacuum spectroscopic chambers

NASA Astrophysics Data System (ADS)

Nelson, A. E.; Schulz, K. H.

2000-06-01

A novel high pressure reaction cell and sample transfer mechanism for ultrahigh vacuum (UHV) spectroscopic chambers is described. The design employs a unique modification of a commercial load-lock transfer system to emulate a tractable microreactor. The reaction cell has an operating pressure range of <1×10-4 to 1000 Torr and can be evacuated to UHV conditions to enable sample transfer into the spectroscopic chamber. Additionally, a newly designed sample holder equipped with electrical and thermocouple contacts is described. The sample holder is capable of resistive specimen heating to 400 and 800 °C with current requirements of 14 A (2 V) and 25 A (3.5 V), respectively. The design enables thorough material science characterization of catalytic reactions and the surface chemistry of catalytic materials without exposing the specimen to atmospheric contaminants. The system is constructed primarily from readily available commercial equipment allowing its rapid implementation into existing laboratories.

Chamber for Growing and Observing Fungi

NASA Technical Reports Server (NTRS)

Pierson, Duane L.; Molina, Thomas C.

2005-01-01

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

Upright Imaging of Drosophila Egg Chambers

PubMed Central

Manning, Lathiena; Starz-Gaiano, Michelle

2015-01-01

Drosophila melanogaster oogenesis provides an ideal context for studying varied developmental processes since the ovary is relatively simple in architecture, is well-characterized, and is amenable to genetic analysis. Each egg chamber consists of germ-line cells surrounded by a single epithelial layer of somatic follicle cells. Subsets of follicle cells undergo differentiation during specific stages to become several different cell types. Standard techniques primarily allow for a lateral view of egg chambers, and therefore a limited view of follicle cell organization and identity. The upright imaging protocol describes a mounting technique that enables a novel, vertical view of egg chambers with a standard confocal microscope. Samples are first mounted between two layers of glycerin jelly in a lateral (horizontal) position on a glass microscope slide. The jelly with encased egg chambers is then cut into blocks, transferred to a coverslip, and flipped to position egg chambers upright. Mounted egg chambers can be imaged on either an upright or an inverted confocal microscope. This technique enables the study of follicle cell specification, organization, molecular markers, and egg development with new detail and from a new perspective. PMID:25867882

Current Pre- and Post-Graduate Vocational Education and Training in Laboratory Medicine and Microbiology in Poland

PubMed Central

Owczarek, Henryk

2010-01-01

The status of Polish medical laboratories in continuously changing. Since 2001 the legal framework was established for the clinical chemists employed in medical and microbiological laboratories. Since that time, the job performance by clinical chemists is limited only to the specialist, member of the Polish Chamber of Laboratory Diagnosticians. According to that legal act, graduate in laboratory medicine is certified to perform the professional activities in medical or microbiological laboratories without further vocational training. After graduating from biology, chemistry, pharmacy or veterinary medicine, a person can perform the job only under supervision of a certified clinical chemist. Several Medical Universities have organized the system of post-graduation education for such graduates. The main courses taught are basic pathology, internal medicine, hematology, immunology, and clinical chemistry. In addition, the Ministry of Health and Chamber of Laboratory Diagnosticians are organizing and supervising the higher level of post-graduate education for clinical chemists, the education and vocational training which leads to the title of specialist in clinical chemistry or similar area in laboratory medicine. The professional qualification of such person are evaluated during the final exam at the national level. The specialist is eligible to act as director of clinical laboratories. PMID:27683359

The link between organic aerosol mass loading and degree of oxygenation: an α-pinene photooxidation study

NASA Astrophysics Data System (ADS)

Pfaffenberger, L.; Barmet, P.; Slowik, J. G.; Praplan, A. P.; Dommen, J.; Prévôt, A. S. H.; Baltensperger, U.

2013-07-01

A series of smog chamber (SC) experiments was conducted to identify factors responsible for the discrepancy between ambient and SC aerosol degree of oxygenation. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer is used to compare mass spectra from α-pinene photooxidation with ambient aerosol. Composition is compared in terms of the fraction of particulate CO2+, a surrogate for carboxylic acids, vs. the fraction of C2H3O+, a surrogate for aldehydes, alcohols and ketones, as well as in the Van Krevelen space, where the evolution of the atomic hydrogen-to-carbon ratio (H : C) vs. the atomic oxygen-to-carbon ratio (O : C) is investigated. Low (near-ambient) organic mass concentrations were found to be necessary to obtain oxygenation levels similar to those of low-volatility oxygenated organic aerosol (LV-OOA) commonly identified in ambient measurements. The effects of organic mass loading and OH (hydroxyl radical) exposure were decoupled by inter-experiment comparisons at the same integrated OH concentration. An OH exposure between 3 and 25 × 107 cm-3 h is needed to increase O : C by 0.05 during aerosol aging. For the first time, LV-OOA-like aerosol from the abundant biogenic precursor α-pinene was produced in a smog chamber by oxidation at typical atmospheric OH concentrations. Significant correlation between measured secondary organic aerosol (SOA) and reference LV-OOA mass spectra is shown by Pearson's R2 values larger than 0.90 for experiments with low organic mass concentrations between 1.2 and 18 μg m-3 at an OH exposure of 4 × 107 cm-3 h, corresponding to about two days of oxidation time in the atmosphere, based on a global mean OH concentration of ~ 1 × 106 cm-3. α-Pinene SOA is more oxygenated at low organic mass loadings. Because the degree of oxygenation influences the chemical, volatility and hygroscopic properties of ambient aerosol, smog chamber studies must be performed at near-ambient concentrations to accurately simulate

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.

Laboratory study of PCBs transport from primary sources to ...

EPA Pesticide Factsheets

The sorption of airborne polychlorinated biphenyls (PCBs) by twenty building materials and their subsequent re-emission (desorption) from concrete were investigated using two 53-L environmental chambers connected in series with a field-collected caulk in the source chamber serving as a stable source of PCBs and building materials in the test chamber. During the tests, the PCB concentrations in the outlet air of the test chamber were monitored and the building materials were removed from the test chamber at different times to determine their PCB content. Among the materials tested, a petroleum-based paint, a latex paint, and a certain type of carpet were among the strongest sinks. Solvent-free epoxy coating, certain types of flooring materials, and brick were among the weakest sinks. For a given sink material, PCB congeners with lower vapor pressures were sorbed in larger quantities. Rough estimates of the partition and diffusion coefficients were obtained by applying a sink model to the data acquired from the chamber studies. A desorption test with the concrete panels showed that re-emission is a slow process, suggesting that PCB sinks, e.g. concrete, can release PCBs into the air for a prolonged period of time (years or decades). This study could fill some of the data gaps associated with the characterization of PCB sinks in contaminated buildings. This paper summarizes the laboratory research results for PCB transport from primary sources to PCB sinks, includ

Modification of the continuous flow diffusion chamber for use in zero-gravity. [atmospheric cloud physics lab

NASA Technical Reports Server (NTRS)

Keyser, G.

1978-01-01

The design philosophy and performance characteristics of the continuous flow diffusion chamber developed for use in ground-based simulation of some of the experiments planned for the atmospheric cloud physics laboratory during the first Spacelab flight are discussed. Topics covered include principle of operation, thermal control, temperature measurement, tem-powered heat exchangers, wettable metal surfaces, sample injection system, and control electronics.

7 CFR 58.423 - Cheese vacuumizing chamber.

Code of Federal Regulations, 2010 CFR

2010-01-01

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

7 CFR 58.423 - Cheese vacuumizing chamber.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Cheese vacuumizing chamber. 58.423 Section 58.423 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....423 Cheese vacuumizing chamber. The vacuum chamber shall be satisfactorily constructed and maintained...

Venturi vacuum systems for hypobaric chamber operations.

PubMed

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

1997-11-01

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

The laboratory astrophysics facility at University College

NASA Astrophysics Data System (ADS)

Hyland, A. R.; Smith, R. G.; Robinson, G.

A laboratory astrophysics facility for the study of the terrestrial analogues of interstellar dust grains is being developed in the Physics Department, University College, Australian Defence Force Academy. The facility consists of a gas handling system for the preparation of samples, a closed-cycle cooler and specimen chamber, and a Fourier Transform Infrared (FTIR) Spectrometer capable of high resolution (0.3/cm) and high sensitivity measurements, currently from 1-25 microns. The layout and construction of the laboratory are described, and the proposed initial experimental program aimed at determining the optical constants of ices, over a wide wavelength range for comparison with astronomical observations, is discussed.

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.

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.

Automated Microbial Metabolism Laboratory

NASA Technical Reports Server (NTRS)

1972-01-01

The Automated Microbial Metabolism Laboratory (AMML) 1971-1972 program involved the investigation of three separate life detection schemes. The first was a continued further development of the labeled release experiment. The possibility of chamber reuse without inbetween sterilization, to provide comparative biochemical information was tested. Findings show that individual substrates or concentrations of antimetabolites may be sequentially added to a single test chamber. The second detection system which was investigated for possible inclusion in the AMML package of assays, was nitrogen fixation as detected by acetylene reduction. Thirdly, a series of preliminary steps were taken to investigate the feasibility of detecting biopolymers in soil. A strategy for the safe return to Earth of a Mars sample prior to manned landings on Mars is outlined. The program assumes that the probability of indigenous life on Mars is unity and then broadly presents the procedures for acquisition and analysis of the Mars sample in a manner to satisfy the scientific community and the public that adequate safeguards are being taken.

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 K Helium Refrigeration System for NASA-JSC Chamber-A

NASA Technical Reports Server (NTRS)

Homan, J.; Redman, R.; Ganni, V.; Sidi-Yekhelef, A.; Knudsen, P.; Norton, R.; Lauterbach, J.; Linza, R.; Vargas, G.

2013-01-01

A new 20 K helium refrigerator installed at NASA Johnson Space Center's Space Environment Simulation Laboratory (SESL) was successfully commissioned and tested in 2012. The refrigerator is used to create a deep space environment within SESL s Chamber A to perform ground testing of the James Webb Space Telescope. The chamber previously and currently still has helium cryopumping panels (CPP) and LN2 shrouds used to create Low Earth Orbit environments. Now with the new refrigerator and new helium shrouds (45 x 65 ) the chamber can create a deep space environment. The process design, system analysis, specification development, and commissioning oversight were performed by the cryogenics department at Jefferson Labs, while the contracts and system installation was performed by the ESC group at JSC. Commissioning data indicate a inverse coefficient of performance better than 70 W/W for a 18 KW load at 20 K (accounting for liquid nitrogen precooling power) that remains essentially constant down to 1/3 of this load. Even at 10 percent of the maximum capacity, the performance is better than 140 W/W at 20K. The refrigerator exceeded all design goals and demonstrated the ability to support a wide load range from 10kW at 15 K to 100 kW at 100K. The refrigerator is capable of operating at any load temperature from 15K to ambient with tight temperature stability. The new shroud (36 tons of aluminum) can be cooled from room temperature to 20 K in 24 hours. This paper will outline the process design and commissioning results.

Development of sputtered techniques for thrust chambers

NASA Technical Reports Server (NTRS)

Mullaly, J. R.; Hecht, R. J.; Schmid, T. E.; Torrey, C. T.

1975-01-01

Techniques and materials were developed and evaluated for the fabrication and coating of advanced, long life, regeneratively cooled thrust chambers. Materials were analyzed as fillers for sputter application of OFHC copper as a closeout layer to channeled inner structures; of the materials evaluated, aluminum was found to provide the highest bond strength and to be the most desirable for chamber fabrication. The structures and properties were investigated of thick sputtered OFHC copper, 0.15 Zr-Cu, Al2O3,-Cu, and SiC-Cu. Layered structures of OFHC copper and 0.15 Zr-Cu were investigated as means of improving chamber inner wall fatigue life. The evaluation of sputtered Ti-5Al-2.5Sn, NASA IIb-11, aluminum and Al2O3-Al alloys as high strength chamber outer jackets was performed. Techniques for refurbishing degraded thrust chambers with OFHC copper and coating thrust chambers with protective ZrO2 and graded ZrO2-copper thermal barrier coatings were developed.

Sequential Notch activation regulates ventricular chamber development

PubMed Central

D'Amato, Gaetano; Luxán, Guillermo; del Monte-Nieto, Gonzalo; Martínez-Poveda, Beatriz; Torroja, Carlos; Walter, Wencke; Bochter, Matthew S.; Benedito, Rui; Cole, Susan; Martinez, Fernando; Hadjantonakis, Anna-Katerina; Uemura, Akiyoshi; Jiménez-Borreguero, Luis J.; de la Pompa, José Luis

2016-01-01

Ventricular chambers are essential for the rhythmic contraction and relaxation occurring in every heartbeat throughout life. Congenital abnormalities in ventricular chamber formation cause severe human heart defects. How the early trabecular meshwork of myocardial fibres forms and subsequently develops into mature chambers is poorly understood. We show that Notch signalling first connects chamber endocardium and myocardium to sustain trabeculation, and later coordinates ventricular patterning and compaction with coronary vessel development to generate the mature chamber, through a temporal sequence of ligand signalling determined by the glycosyltransferase manic fringe (MFng). Early endocardial expression of MFng promotes Dll4–Notch1 signalling, which induces trabeculation in the developing ventricle. Ventricular maturation and compaction require MFng and Dll4 downregulation in the endocardium, which allows myocardial Jag1 and Jag2 signalling to Notch1 in this tissue. Perturbation of this signalling equilibrium severely disrupts heart chamber formation. Our results open a new research avenue into the pathogenesis of cardiomyopathies. PMID:26641715

A radial time projection chamber for α detection in CLAS at JLab

DOE PAGES

Dupre, R.; Stepanyan, S.; Hattawy, M.; ...

2018-08-01

A new Radial Time Projection Chamber (RTPC) was developed at the Jefferson Laboratory to track low-energy nuclear recoils to measure exclusive nuclear reactions, such as coherent deeply virtual Compton scattering and coherent meson production off 4He. In 2009, we carried out these measurements using the CEBAF Large Acceptance Spectrometer (CLAS) supplemented by the RTPC positioned directly around a gaseous 4He target, allowing a detection threshold as low as 12 MeV for 4He. This work discusses the design, principle of operation, calibration methods and performances of this RTPC.

A radial time projection chamber for α detection in CLAS at JLab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dupre, R.; Stepanyan, S.; Hattawy, M.

A new Radial Time Projection Chamber (RTPC) was developed at the Jefferson Laboratory to track low-energy nuclear recoils to measure exclusive nuclear reactions, such as coherent deeply virtual Compton scattering and coherent meson production off 4He. In 2009, we carried out these measurements using the CEBAF Large Acceptance Spectrometer (CLAS) supplemented by the RTPC positioned directly around a gaseous 4He target, allowing a detection threshold as low as 12 MeV for 4He. This work discusses the design, principle of operation, calibration methods and performances of this RTPC.

Vacuum chamber with a supersonic flow aerodynamic window

DOEpatents

Hanson, Clark L.

1982-01-01

A supersonic flow aerodynamic window, whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

Vacuum chamber with a supersonic-flow aerodynamic window

DOEpatents

Hanson, C.L.

1980-10-14

A supersonic flow aerodynamic window is disclosed whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

Acute shallowing of the anterior chamber.

PubMed Central

Mapstone, R

1981-01-01

In aging eyes phenylephrine drops have no significant effect on the depth of the anterior chamber, whereas pilocarpine drops produce a significant shallowing. If both drugs are instilled simultaneously, a significantly greater decrease in anterior chamber depth occurs. The effect is seen in normal, glaucomatous, and hypertensive eyes, and in eyes with shallow anterior chambers. It did not occur in eyes that had had an iridectomy. During the course of a positive provocative test an acute reduction in anterior depth occurs which is reversed when the angle opens and pressure returns to normal levels. It is concluded that the depth of the anterior chamber is not a static dimension but that changes can occur which are rapid and transient. The mechanism of shallowing and deepening depends on an increase or a decrease in the pupil block force. It is a necessary consequence too that eyes with nonshallow anterior chambers can get closed-angle glaucoma and that this possibility cannot be detected by a conventional gonioscopic approach. PMID:6455153

PICASSO, COUPP and PICO - Search for dark matter with bubble chambers

DOE PAGES

Amole, C.; Ardid, M.; Asner, D. M.; ...

2015-05-29

The PICASSO and COUPP collaborations use superheated liquid detectors to search for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs). These experiments, located in the underground laboratory of SNOLAB, Canada, detect phase transitions triggered by nuclear recoils in the keV range induced by interactions with WIMPs. We present details of the construction and operation of these detectors as well as the results, obtained by several years of observations. We also introduce PICO, which is a joint effort of the two collaborations to build a second generation ton-scale bubble chamber with 250 liters of active liquid.

Outgassing measurement of the aluminum alloy UHV chamber

NASA Technical Reports Server (NTRS)

Miyamoto, M.; Itoh, T.; Komaki, S.; Narushima, K.; Ishimaru, H.

1986-01-01

A large vacuum chamber (580 mm diameter) was fabricated from an aluminum alloy surface treated by a special process normally used on small chambers. The chamber was tested unbaked and baked at various temperatures, pressures, and holding periods. The chamber was filled with N2 gas, and the outgassing rate was measured after one hour. Then the ultimate pressure was measured. Outgassing rates for baked and unbaked groups were compared. It is concluded that the same surface treatment technique can be used on both large and small chambers produced by the same special extrusion process.

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

Note: Small anaerobic chamber for optical spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chauvet, Adrien A. P., E-mail: adrien.chauvet@gmail.com; Chergui, Majed; Agarwal, Rachna

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, tomore » the sample and (2) allows the sample position to be adjusted while keeping the chamber fixed and hermetic during the experiment.« less

Numerical simulation of magma chamber dynamics.

NASA Astrophysics Data System (ADS)

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

2010-05-01

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

Making MUSIC: A multiple sampling ionization chamber

NASA Astrophysics Data System (ADS)

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

2007-08-01

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

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…

Design and Control of Small Neutral Beam Arc Chamber for Investigations of DIII-D Neutral Beam Failure During Helium Operation

NASA Astrophysics Data System (ADS)

Fremlin, Carl; Beckers, Jasper; Crowley, Brendan; Rauch, Joseph; Scoville, Jim

2017-10-01

The Neutral Beam system on the DIII-D tokamak consists of eight ion sources using the Common Long Pulse Source (CLPS) design. During helium operation, desired for research regarding the ITER pre-nuclear phase, it has been observed that the ion source arc chamber performance steadily deteriorates, eventually failing due to electrical breakdown of the insulation. A significant investment of manpower and time is required for repairs. To study the cause of failure a small analogue of the DIII-D neutral beam arc chamber has been constructed. This poster presents the design and analysis of the arc chamber including the PLC based operational control system for the experiment, analysis of the magnetic confinement and details of the diagnostic suite. Work supported in part by US DoE under the Science Undergraduate Laboratory Internship (SULI) program and under DE-FC02-04ER54698.

A new ring-shaped graphite monitor ionization chamber

NASA Astrophysics Data System (ADS)

Yoshizumi, M. T.; Caldas, L. V. E.

2010-07-01

A ring-shaped monitor ionization chamber was developed at the Instituto de Pesquisas Energéticas e Nucleares. This ionization chamber presents an entrance window of aluminized polyester foil. The guard ring and collecting electrode are made of graphite coated Lucite plates. The main difference between this new ionization chamber and commercial monitor chambers is its ring-shaped design. The new monitor chamber has a central hole, allowing the passage of the direct radiation beam without attenuation; only the penumbra radiation is measured by the sensitive volume. This kind of ionization chamber design has already been tested, but using aluminium electrodes. By changing the electrode material from aluminium to a graphite coating, an improvement in the chamber response stability was expected. The pre-operational tests, as saturation curve, recombination loss and polarity effect showed satisfactory results. The repeatability and the long-term stability tests were also evaluated, showing good agreement with international recommendations.

Team Huddle Before Lifting Phoenix into Test Chamber

NASA Technical Reports Server (NTRS)

2007-01-01

Spacecraft specialists huddle to discuss the critical lift of NASA's Phoenix Mars Lander into a thermal vacuum chamber.

In December 2006, the spacecraft was in a cruise configuration prior to going into environmental testing at a Lockheed Martin Space Systems facility near Denver. At all stages of assembly and testing, the spacecraft is handled with extreme care and refinement.

The Phoenix mission is led by Principal Investigator Peter H. Smith of the University of Arizona, Tucson, with project management at NASA's Jet Propulsion Laboratory and development partnership with Lockheed Martin Space Systems. International contributions for Phoenix are provided by the Canadian Space Agency, the University of Neuchatel (Switzerland), the University of Copenhagen, and the Max Planck Institute in Germany. JPL is a division of the California Institute of Technology in Pasadena.

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

Ionization chamber correction factors for MR-linacs

NASA Astrophysics Data System (ADS)

Pojtinger, Stefan; Steffen Dohm, Oliver; Kapsch, Ralf-Peter; Thorwarth, Daniela

2018-06-01

Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B. The purpose of this study is to systematically investigate k B for a typical reference setup for commercially available ionization chambers with different magnetic field strengths. The Monte Carlo simulation tool EGSnrc was used to simulate eight commercially available ionization chambers in magnetic fields whose magnetic flux density was in the range of 0–2.5 T. To validate the simulation, the influence of the magnetic field was experimentally determined for a PTW30013 Farmer-type chamber for magnetic flux densities between 0 and 1.425 T. Changes in the detector response of up to 8% depending on the magnetic flux density, on the chamber geometry and on the chamber orientation were obtained. In the experimental setup, a maximum deviation of less than 2% was observed when comparing measured values with simulated values. Dedicated values for two MR-linac systems (ViewRay MRIdian, ViewRay Inc, Cleveland, United States, 0.35 T/ 6 MV and Elekta Unity, Elekta AB, Stockholm, Sweden, 1.5 T/7 MV) were determined for future use in reference dosimetry. Simulated values for thimble-type chambers are in good agreement with experiments as well as with the results of previous publications. After further experimental validation, the results can be considered for definition of standard protocols for purposes of reference dosimetry in MRgRT.

Ionization chamber correction factors for MR-linacs.

PubMed

Pojtinger, Stefan; Dohm, Oliver Steffen; Kapsch, Ralf-Peter; Thorwarth, Daniela

2018-06-07

Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B . The purpose of this study is to systematically investigate k B for a typical reference setup for commercially available ionization chambers with different magnetic field strengths. The Monte Carlo simulation tool EGSnrc was used to simulate eight commercially available ionization chambers in magnetic fields whose magnetic flux density was in the range of 0-2.5 T. To validate the simulation, the influence of the magnetic field was experimentally determined for a PTW30013 Farmer-type chamber for magnetic flux densities between 0 and 1.425 T. Changes in the detector response of up to 8% depending on the magnetic flux density, on the chamber geometry and on the chamber orientation were obtained. In the experimental setup, a maximum deviation of less than 2% was observed when comparing measured values with simulated values. Dedicated values for two MR-linac systems (ViewRay MRIdian, ViewRay Inc, Cleveland, United States, 0.35 T/ 6 MV and Elekta Unity, Elekta AB, Stockholm, Sweden, 1.5 T/7 MV) were determined for future use in reference dosimetry. Simulated values for thimble-type chambers are in good agreement with experiments as well as with the results of previous publications. After further experimental validation, the results can be considered for definition of standard protocols for purposes of reference dosimetry in MRgRT.

Organic aerosol formation in citronella candle plumes.

PubMed

Bothe, Melanie; Donahue, Neil McPherson

2010-09-01

Citronella candles are widely used as insect repellants, especially outdoors in the evening. Because these essential oils are unsaturated, they have a unique potential to form secondary organic aerosol (SOA) via reaction with ozone, which is also commonly elevated on summer evenings when the candles are often in use. We investigated this process, along with primary aerosol emissions, by briefly placing a citronella tealight candle in a smog chamber and then adding ozone to the chamber. In repeated experiments, we observed rapid and substantial SOA formation after ozone addition; this process must therefore be considered when assessing the risks and benefits of using citronella candle to repel insects.

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

NASA Astrophysics Data System (ADS)

Mateo-Marti, Eva

2014-08-01

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

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.

An economical model for simulating droplet spectrum evolution in turbulent cloud chambers and wind tunnels

NASA Astrophysics Data System (ADS)

Krueger, Steven; Cantrell, W.; Niedermeier, D.; Shaw, R.; Stratmann, F.

2017-11-01

Although airborne instruments provide detailed information about the microphysical structure of clouds, the measurements provide only a few snapshots of each cloud. Deducing the droplet spectrum evolution from such measurements is next to impossible. We are using two alternative approaches: laboratory studies and numerical simulations. The former relies on a new turbulent cloud chamber (the Pi Chamber) at Michigan Technical University, as well as the first humid turbulent wind tunnel (LACIS-T) at the Leibniz Institute for Tropospheric Research. Both produce conditions for droplet growth (i.e., supersaturation) by mixing saturated vapor at different temperatures. The Pi Chamber produces turbulence by inducing Rayleigh-Bénard convection, while the wind tunnel generates turbulence with a grid. We are using the Explicit Mixing Parcel Model (EMPM) to numerically simulate droplet spectrum evolution in these flows. The EMPM explicitly links turbulent mixing and droplet spectrum evolution by representing a turbulent flow in a 1D domain with the linear eddy model. The EMPM can economically span scales from those of the smallest turbulent eddies to those of the largest. The EMPM grows or evaporates thousands of individual cloud droplets according to their local environments.

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.

Investigation of the chamber correction factor (k(ch)) for the UK secondary standard ionization chamber (NE2561/NE2611) using medium-energy x-rays.

PubMed

Rosser, K E

1998-11-01

This paper evaluates the characteristics of ionization chambers for the measurement of absorbed dose to water for medium-energy x-rays. The values of the chamber correction factor, k(ch), used in the IPEMB code of practice for the UK secondary standard (NE2561/NE2611) ionization chamber are derived and their constituent factors examined. The comparison of the chambers' responses in air revealed that of the chambers tested only the NE2561, NE2571 and NE2505 exhibit a flat (within 5%) energy response in air. Under no circumstances should the NACP, Sanders electron chamber, or any chamber that has a wall made of high atomic number material, be used for medium-energy x-ray dosimetry. The measurements in water reveal that a chamber that has a substantial housing, such as the PTW Grenz chamber, should not be used to measure absorbed dose to water in this energy range. The value of k(ch) for an NE2561 chamber was determined by measuring the absorbed dose to water and comparing it with that for an NE2571 chamber, for which k(ch) data have been published. The chamber correction factor varies from 1.023 +/- 0.03 to 1.018 +/- 0.001 for x-ray beams with HVL between 0.15 and 4 mm Cu. The values agree with that for an NE2571 chamber within the experimental uncertainty. The corrections due to the stem, waterproof sleeve and replacement of the phantom material by the chamber for an NE2561 chamber are described.

Effect of headspace mixing in static chambers and sampling protocol on calculated CH4 fluxes from soils

NASA Astrophysics Data System (ADS)

Juszczak, R.; Pihlatie, M.; Christiansen, J. R.; Giebels, M.; Schreiber, P.; Aaltonen, H.; Korhonen, J.; Rasilo, T.; Chojnicki, B. H.; Urbaniak, M.

2009-04-01

continuously with 1Hz frequency. Additionally, two different manual samplings procedures were tested and gas samples from chamber headspace were taken for gas chromatograph (GC) and analysed in two different laboratories. Gas concentrations in the calibration tank were monitored with a GC and an automatic gas analyzer (INNOVA). The preliminary results showed that air mixing inside the chamber headspace, the way of chamber handling and sampling procedures could have pronounced influence on the trace gas concentration detection inside a chamber, and as a consequence the calculated chamber fluxes. The moment of chamber enclosure can lead to a rapid increase in CH4 concentration due to a pressure effect in the chambers without a vent tube. Thus, it is essential to critically estimate the time of the first sampling so that it is early enough after chamber enclosure, but not disturbed by the initial chamber handling. It was also observed that manual sampling of gas can change the CH4 concentration in the chamber headspace. When mixing the chamber headspace air by a syringe, the subsequent gas sampling in the syringe may affect the diffusion of gas between the soil and the chamber headspace, and hence affect the calculated fluxes. It was observed that mixing the chamber headspace with a fan instead of syringes, reduced this effect during the chamber enclosure. Overall, fluxes measured with chamber equipped with a fan always gave higher fluxes (up to 40%) as compared to fluxes measured from chambers without a fan. Results of our experiment lead to the assumption that these differences were generally larger the higher the chamber was, the less porous the soil was, and the higher the fluxes were. We conclude from our experiment that static chambers used for greenhouse gas flux measurements should be equipped with at least one fan and a vent tube to increase mixing and reduce pressure propagation in the chamber-soil system, and that special attention should be paid to the handling of the

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

Qualitative Flow Visualization of a 110-N Hydrogen/Oxygen Laboratory Model Thruster

NASA Technical Reports Server (NTRS)

deGroot, Wim A.; McGuire, Thomas J.; Schneider, Steven J.

1997-01-01

The flow field inside a 110 N gaseous hydrogen/oxygen thruster was investigated using an optically accessible, two-dimensional laboratory test model installed in a high altitude chamber. The injector for this study produced an oxidizer-rich core flow, which was designed to fully mix and react inside a fuel-film sleeve insert before emerging into the main chamber section, where a substantial fuel film cooling layer was added to protect the chamber wall. Techniques used to investigate the flow consisted of spontaneous Raman spectra measurements, visible emission imaging, ultraviolet hydroxyl spectroscopy, and high speed schlieren imaging. Experimental results indicate that the oxygen rich core flow continued to react while emerging from the fuel-film sleeve, suggesting incomplete mixing of the hydrogen in the oxygen rich core flow. Experiments also showed that the fuel film cooling protective layer retained its integrity throughout the straight section of the combustion chamber. In the converging portion of the chamber, however, a turbulent reaction zone near the wall destroyed the integrity of the film layer, a result which implies that a lower contraction angle may improve the fuel film cooling in the converging section and extend the hardware lifetime.

Experimental investigation of a lightweight rocket chamber

NASA Technical Reports Server (NTRS)

Dalgleish, John E; Tischler, Adelbert O

1953-01-01

Experiments have been conducted with a jacketed rocket combustion chamber that was fabricated by hydraulic-forming from sheet metal. Rocket combustion chambers made by this method have been used successfully. Runs with these combustion chambers have been made at over-all heat-transfer rates 1.7 Btu per square inch per second with water cooling and also ammonia as a regenerative coolant.

A numerical cloud model for the support of laboratory experimentation

NASA Technical Reports Server (NTRS)

Hagen, D. E.

1979-01-01

A numerical cloud model is presented which can describe the evolution of a cloud starting from moist aerosol-laden air through the diffusional growth regime. The model is designed for the direct support of cloud chamber laboratory experimentation, i.e., experiment preparation, real-time control and data analysis. In the model the thermodynamics is uncoupled from the droplet growth processes. Analytic solutions for the cloud droplet growth equations are developed which can be applied in most laboratory situations. The model is applied to a variety of representative experiments.

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.

Autoignition Chamber for Remote Testing of Pyrotechnic Devices

NASA Technical Reports Server (NTRS)

Harrington, Maureen L.; Steward, Gerald R.; Dartez, Toby W.

2009-01-01

The autoignition chamber (AIC) performs by remotely heating pyrotechnic devices that can fit the inner diameter of the tube furnace. Two methods, a cold start or a hot start, can be used with this device in autoignition testing of pyrotechnics. A cold start means extending a pyrotechnic device into the cold autoignition chamber and then heating the device until autoignition occurs. A hot start means heating the autoignition chamber to a specified temperature, and then extending the device into a hot autoignition chamber until autoignition occurs. Personnel are remote from the chamber during the extension into the hot chamber. The autoignition chamber, a commercially produced tubular furnace, has a 230-V, single-phase, 60-Hz electrical supply, with a total power output of 2,400 W. It has a 6-in. (15.2-cm) inner diameter, a 12-in. (30.4-cm) outer diameter and a 12-in.- long (30.4-cm), single-zone, solid tubular furnace (element) capable of heating to temperatures up to 2,012 F (1,100 C) in air.

Theoretical Performance of Hydrogen-Oxygen Rocket Thrust Chambers

NASA Technical Reports Server (NTRS)

Sievers, Gilbert K.; Tomazic, William A.; Kinney, George R.

1961-01-01

Data are presented for liquid-hydrogen-liquid-oxygen thrust chambers at chamber pressures from 15 to 1200 pounds per square inch absolute, area ratios to approximately 300, and percent fuel from about 8 to 34 for both equilibrium and frozen composition during expansion. Specific impulse in vacuum, specific impulse, combustion-chamber temperature, nozzle-exit temperature, characteristic velocity, and the ratio of chamber-to-nozzle-exit pressure are included. The data are presented in convenient graphical forms to allow quick calculation of theoretical nozzle performance with over- or underexpansion, flow separation, and introduction of the propellants at various initial conditions or heat loss from the combustion chamber.

Propane and butane emission sources to ambient air of Mexico City metropolitan area.

PubMed

Jaimes, L; Sandoval, J

2002-04-22

Samples of volatile organic compounds (VOCs) were collected in a smog chamber in order to determine whether automotive exhausts or LP Gas emissions play a greater role in the source of propane and butane, which affect ozone formation and other pollutants in the ambient air of the Mexico City metropolitan area (MCMA). These samples were collected in April 1995 during mornings and evenings. The testing methodology used for measuring exhaust emission were FTP or EPA-74 tests, and SHED type tests were also conducted in order to evaluate evaporative emissions. The finding from analysis of the VOCs collected in the morning demonstrate that in the atmosphere, propane concentrations are higher than that of butane but the reverse in evaporative and exhaust emissions, with the concentration of propane lower than that of butane. Our conclusion is that most of C3 and C4 in the ambient air comes from LP gas and not vehicle exhaust or evaporative emission, due to the higher levels of propane than butane in its formulation. The analysis of VOCs also indicates that although the conversion (in the smog chamber) of alkanes is low during the day, due to the high initial concentration, their contribution in the reaction mechanism to produce ozone can be appreciable.

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.

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

Characterization of Gas Transport Properties of Fractured Rocks By Borehole and Chamber Tests.

NASA Astrophysics Data System (ADS)

Shimo, M.; Shimaya, S.; Maejima, T.

2014-12-01

were detected in the data of the pore pressure as well as AE monitoring around the chamber. Results from the above two tests were simulated using a multi-phase transport simulator, TOUGH2, developed at Lawrence Berkeley National Laboratory. Fig.2 shows the model and an example of the simulation.

Modern dosimetric tools for 60Co irradiation at high containment laboratories

PubMed Central

Twardoski, Barri; Feldmann, Heinz; Bloom, Marshall E.; Ward, Joe

2011-01-01

Purpose To evaluate an innovative photo-fluorescent film as a routine dosimetric tool during 60Co irradiations at a high containment biological research laboratory, and to investigate whether manufacturer-provided chamber exposure rates can be used to accurately administer a prescribed dose to biological specimens. Materials and methods Photo-fluorescent, lithium fluoride film dosimeters and National Institutes of Standards and Technology (NIST) transfer dosimeters were co-located in a self-shielded 60Co irradiator and exposed to γ-radiation with doses ranging from 5–85 kGy. Film dose-response relationships were developed for varying temperatures simulating conditions present when irradiating infectious biological specimens. Dose measurement results from NIST transfer dosimeters were compared to doses predicted using manufacturer-provided irradiator chamber exposure rates. Results The film dosimeter exhibited a photo-fluorescent response signal that was consistent and nearly linear in relationship to γ-radiation exposure over a wide dose range. The dosimeter response also showed negligible effects from dose fractionization and humidity. Significant disparities existed between manufacturer-provided chamber exposure rates and actual doses administered. Conclusion This study demonstrates the merit of utilizing dosimetric tools to validate the process of exposing dangerous and exotic biological agents to γ-radiation at high containment laboratories. The film dosimeter used in this study can be utilized to eliminate potential for improperly administering γ-radiation doses. PMID:21961968

Laboratory-based validation of the baseline sensors of the ITER diagnostic residual gas analyzer

NASA Astrophysics Data System (ADS)

Klepper, C. C.; Biewer, T. M.; Marcus, C.; Andrew, P.; Gardner, W. L.; Graves, V. B.; Hughes, S.

2017-10-01

The divertor-specific ITER Diagnostic Residual Gas Analyzer (DRGA) will provide essential information relating to DT fusion plasma performance. This includes pulse-resolving measurements of the fuel isotopic mix reaching the pumping ducts, as well as the concentration of the helium generated as the ash of the fusion reaction. In the present baseline design, the cluster of sensors attached to this diagnostic's differentially pumped analysis chamber assembly includes a radiation compatible version of a commercial quadrupole mass spectrometer, as well as an optical gas analyzer using a plasma-based light excitation source. This paper reports on a laboratory study intended to validate the performance of this sensor cluster, with emphasis on the detection limit of the isotopic measurement. This validation study was carried out in a laboratory set-up that closely prototyped the analysis chamber assembly configuration of the baseline design. This includes an ITER-specific placement of the optical gas measurement downstream from the first turbine of the chamber's turbo-molecular pump to provide sufficient light emission while preserving the gas dynamics conditions that allow for \\textasciitilde 1 s response time from the sensor cluster [1].

LEGO bricks used as chemotactic chambers: evaluation by a computer-assisted image analysis technique.

PubMed

Azzarà, A; Chimenti, M

2004-01-01

One of the main techniques used to explore neutrophil motility, employs micropore filters in chemotactic chambers. Many new models have been proposed, in order to perform multiple microassays in a rapid, inexpensive and reproducible way. In this work, LEGO bricks have been used as chemotactic chambers in the evaluation of neutrophil random motility and chemotaxis and compared with conventional Boyden chambers in a "time-response" experiment. Neutrophil motility throughout the filters was evaluated by means of an image-processing workstation, in which a dedicated algorithm recognizes and counts the cells in several fields and focal planes throughout the whole filter; correlates counts and depth values; performs a statistical analysis of data; calculates the true value of neutrophil migration; determines the distribution of cells; and displays the migration pattern. By this method, we found that the distances travelled by the cells in conventional chambers and in LEGO bricks were perfectly identical, both in random migration and under chemotactic conditions. Moreover, no interference with the physiological behaviour of neutrophils was detectable. In fact, the kinetics of migration was identical both in random migration (characterized by a gaussian pattern) and in chemotaxis (characterized by a typical stimulation peak, previously identified by our workstation). In conclusion, LEGO bricks are extremely precise devices. They are simple to use and allow the use of small amounts of chemoattractant solution and cell suspension, supplying by itself a triplicate test. LEGO bricks are inexpensive, fast and suitable for current diagnostic activity or for research investigations in every laboratory.

ATMOSPHERIC CHEMISTRY OF SELECTED SULFUR-CONTAINING COMPOUNDS OUTDOOR SMOG CHAMBER STUDY - PHASE 1

EPA Science Inventory

The chemical behavior of hydrogen sulfide, carbonyl sulfide, carbon sulfide, methanethiol, ethanethiol, methyl sulfide, ethylsulfide, methyl-disulfide, ethyldisulfide, methylethylsulfide, thiophene, 2-methylthiophene, 3-methylthiophene, 2,5-dimethyl-thiophene and propene (used as...

SMOG CHAMBER STUDIES OF SECONDARY ORGANIC AEROSOLS FROM IRRADIATED HYDROCARBONS UNDER AMBIENT CONDITIONS

EPA Science Inventory

Understanding the physics and chemistry of aerosols is fundamental to evaluating health risks and developing and evaluating atmospheric models. However, as noted in a recent NRC report only about 10% of the organics in PM2.5 have been identified. A significant portion of the un...

Long-term stability of radiotherapy dosimeters calibrated at the Polish Secondary Standard Dosimetry Laboratory.

PubMed

Ulkowski, Piotr; Bulski, Wojciech; Chełmiński, Krzysztof

2015-10-01

Unidos 10001, Unidos E (10008/10009) and Dose 1 electrometers from 14 radiotherapy centres were calibrated 3-4 times over a long period of time, together with Farmer type (PTW 30001, 30013, Nuclear Enterprises 2571 and Scanditronix-Wellhofer FC65G) cylindrical ionization chambers and plane-parallel type chambers (PTW Markus 23343 and Scanditronix-Wellhofer PPC05). On the basis of the long period of repetitive establishing of calibration coefficients for the same electrometers and ionization chambers, the accuracy of electrometers and the long-term stability of ionization chambers were examined. All measurements were carried out at the same laboratory, by the same staff, according to the same IAEA recommendations. A good accuracy and long-term stability of the dosimeters used in Polish radiotherapy centres was observed. These values were within 0.1% for electrometers and 0.2% for the chambers with electrometers. Furthermore, these values were not observed to vary over time. The observations confirm the opinion that the requirement of calibration of the dosimeters more often than every 2 years is not justified. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Wireless transmission of biosignals for hyperbaric chamber applications

PubMed Central

Perez-Vidal, Carlos; Gracia, Luis; Carmona, Cristian; Alorda, Bartomeu; Salinas, Antonio

2017-01-01

This paper presents a wireless system to send biosignals outside a hyperbaric chamber avoiding wires going through the chamber walls. Hyperbaric chambers are becoming more and more common due to new indications of hyperbaric oxygen treatments. Metallic walls physically isolate patients inside the chamber, where getting a patient’s vital signs turns into a painstaking task. The paper proposes using a ZigBee-based network to wirelessly transmit the patient's biosignals to the outside of the chamber. In particular, a wearable battery supported device has been designed, implemented and tested. Although the implementation has been conducted to transmit the electrocardiography signal, the device can be easily adapted to consider other biosignals. PMID:28296900

Laboratory investigation of fire radiative energy and smoke aerosol emissions

Treesearch

Charles Ichoku; J. Vanderlei Martins; Yoram J. Kaufman; Martin J. Wooster; Patrick H. Freeborn; Wei Min Hao; Stephen Baker; Cecily A. Ryan; Bryce L. Nordgren

2008-01-01

Fuel biomass samples from southern Africa and the United States were burned in a laboratory combustion chamber while measuring the biomass consumption rate, the fire radiative energy (FRE) release rate (Rfre), and the smoke concentrations of carbon monoxide (CO), carbon dioxide (CO2), and particulate matter (PM). The PM mass emission rate (RPM) was quantified from...

IFE Chamber Technology - Status and Future Challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, W.R.; Raffray, A.R.; Abdel-Khalik, S.I.

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.

Low-Cost, High-Performance Combustion Chamber

NASA Technical Reports Server (NTRS)

Fortini, Arthur J.

2015-01-01

Ultramet designed and fabricated a lightweight, high-temperature combustion chamber for use with cryogenic LOX/CH4 propellants that can deliver a specific impulse of approx.355 seconds. This increase over the current 320-second baseline of nitrogen tetroxide/monomethylhydrazine (NTO/MMH) will result in a propellant mass decrease of 55 lb for a typical lunar mission. The material system was based on Ultramet's proven oxide-iridium/rhenium architecture, which has been hot-fire tested with stoichiometric oxygen/hydrogen for hours. Instead of rhenium, however, the structural material was a niobium or tantalum alloy that has excellent yield strength at both ambient and elevated temperatures. Phase I demonstrated alloys with yield strength-to-weight ratios more than three times that of rhenium, which will significantly reduce chamber weight. The starting materials were also two orders of magnitude less expensive than rhenium and were less expensive than the C103 niobium alloy commonly used in low-performance engines. Phase II focused on the design, fabrication, and hot-fire testing of a 12-lbf thrust class chamber with LOX/CH4, and a 100-lbf chamber for LOX/CH4. A 5-lbf chamber for NTO/MMH also was designed and fabricated.

Polarity effects and apparent ion recombination in microionization chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Jessica R., E-mail: miller@humonc.wisc.edu; Hooten, Brian D.; Micka, John A.

Purpose: Microchambers demonstrate anomalous voltage-dependent polarity effects. Existing polarity and ion recombination correction factors do not account for these effects. As a result, many commercial microchamber models do not meet the specification of a reference-class ionization chamber as defined by the American Association of Physicists in Medicine. The purpose of this investigation is to determine the cause of these voltage-dependent polarity effects. Methods: A series of microchamber prototypes were produced to isolate the source of the voltage-dependent polarity effects. Parameters including ionization-chamber collecting-volume size, stem and cable irradiation, chamber assembly, contaminants, high-Z materials, and individual chamber components were investigated. Measurementsmore » were performed with electrodes coated with graphite to isolate electrode conductivity. Chamber response was measured as the potential bias of the guard electrode was altered with respect to the collecting electrode, through the integration of additional power supplies. Ionization chamber models were also simulated using COMSOL Multiphysics software to investigate the effect of a potential difference between electrodes on electric field lines and collecting volume definition. Results: Investigations with microchamber prototypes demonstrated that the significant source of the voltage-dependent polarity effects was a potential difference between the guard and collecting electrodes of the chambers. The voltage-dependent polarity effects for each prototype were primarily isolated to either the guard or collecting electrode. Polarity effects were reduced by coating the isolated electrode with a conductive layer of graphite. Polarity effects were increased by introducing a potential difference between the electrodes. COMSOL simulations further demonstrated that for a given potential difference between electrodes, the collecting volume of the chamber changed as the applied voltage was

Effects of outgassing of loader chamber walls on hydriding of thin films for commercial applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Provo, James L., E-mail: jlprovo@verizon.net

2014-07-01

An important aspect of understanding industrial processing is to know the characteristics of the materials used in such processes. A study was performed to determine the effects of hydriding chamber material on the degree of hydriding for the commercial production of thin film hydride targets for various research universities, commercial companies, and government national laboratories. The goal was to increase the degree of hydriding of various thin film hydrides and to study the vacuum environment during air-exposure hydriding. For this purpose, dynamic residual gas analysis during deuterium gas hydride processing was utilized with erbium thin films, employing a special set-upmore » for direct dynamic hydride gas sampling during processing at elevated temperature and full loading gas pressure. Complete process data for (1) a copper–(1.83 wt. %)beryllium wet hydrogen fired passivated (600 °C–1 h) externally heated pipe hydriding chamber are reported. Dynamic residual gas analysis comparisons during hydriding are presented for hydriding chambers made from (2) alumina (99.8 wt. %), (3) copper (with an interior aluminum coating ∼10 k Å thick, and (4) for a stainless-steel air-fired passivated (900 °C–1 h) chamber. Dynamic data with deuterium gas in the chamber at the hydriding temperature (450 °C) showed the presence and growth of water vapor (D{sub 2}O) and related mixed ion species(H{sub 2}O{sup +}, HDO{sup +}, D{sub 2}O{sup +}, and OD{sup +}) from hydrogen isotope exchange reactions during the 1 h process time. Peaks at mass-to-charge ratios (i.e., m/e) of 12(C{sup +}), 16(CD{sub 2}{sup +}), 17(CHD{sub 2}{sup +}), and 18(CD{sub 3}{sup +}, OD{sup +}) increased for approximately the first half hour of a 1 h hydriding process and then approach steady state. Mass-to-charge peaks at 19(HDO{sup +}) and 20(D{sub 2}O{sup +}) continue to increase throughout the process cycle. Using the m/e = 20 (D{sub 2}O{sup +}) peak intensity from

Effects of open-top chambers on 'Valencia' orange trees

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olszyk, D.M.; Takemoto, B.K.; Kats, G.

1992-01-01

Young 'Valencia' orange trees (Citrus sinensis(L) Osbeck) were grown for four years in large open-top chambers with ambient (nonfiltered) air or in outside air to determine any effects of the chambers on the air pollutant susceptibility of the trees. Long-term ozone average concentrations (12 hours, growing season) were 8% lower, and cumulative ozone dose (hourly values >0.1 microL/L) was 29% lower in ambient chambers compared to outside air. Fruit yields were much higher (>39%) for ambient chamber trees than for outside trees over three harvests, due at least partly to less fruit drop during the growing season for ambient chambermore » trees. Ambient chamber trees were much larger than outside trees and produced over twice as much leaf material over four years of study. Leaves on ambient chamber trees were larger and less dense than on outside trees. Leaves on ambient chamber trees were under more stress than leaves on outside trees during summer months; with lower stomatal conductances (14% average) and transpiration rates (12%), and more negative leaf water pressure potentials (28%). In contrast, leaves on ambient chamber trees had higher net photosynthetic rates (13%) and higher leaf starch concentrations prior to tree flowering (31%), than leaves on outside trees. While these results indicated large long-term impacts on tree growth which must be considered when using open-top chambers, they did not indicate any net effect of chambers on the air pollutant susceptibility of trees which would limit the usefulness of chamber tree data for air quality impact assessment purposes.« less

Commissioning of the Active-Target Time Projection Chamber

NASA Astrophysics Data System (ADS)

Bradt, J.; Bazin, D.; Abu-Nimeh, F.; Ahn, T.; Ayyad, Y.; Beceiro Novo, S.; Carpenter, L.; Cortesi, M.; Kuchera, M. P.; Lynch, W. G.; Mittig, W.; Rost, S.; Watwood, N.; Yurkon, J.

2017-12-01

The Active-Target Time Projection Chamber (AT-TPC) was recently built and commissioned at the National Superconducting Cyclotron Laboratory at Michigan State University. This gas-filled detector uses an active-target design where the gas acts as both the tracking medium and the reaction target. Operating inside a 2T solenoidal magnetic field, the AT-TPC records charged particle tracks that can be reconstructed to very good energy and angular resolutions. The near- 4 π solid angle coverage and thick target of the detector are well-suited to experiments with low secondary beam intensities. In this paper, the design and instrumentation of theAT-TPC are described along with the methods used to analyze the data it produces. A simulation of the detector's performance and some results from its commissioning with a radioactive 46Ar beam are also presented.

Dark Matter Search Results from the PICO-60 C$$_3$$F$$_8$$ Bubble Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amole, C.; et al.

2017-02-24

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of Cmore » $$_3$$F$$_8$$ located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C$$_3$$F$$_8$$ exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than 1 event per month. A blind analysis of an efficiency-corrected 1167-kg-day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the WIMP-proton spin-dependent cross section at 3.4 $$\\times$$ 10$$^{-41}$$ cm$^2$ for a 30-GeV$$\\thinspace$$c$$^{-2}$$ WIMP, more than one order of magnitude improvement from previous PICO results.« less

Dark Matter Search Results from the PICO -60 C 3F8 Bubble Chamber

NASA Astrophysics Data System (ADS)

Amole, C.; Ardid, M.; Arnquist, I. J.; Asner, D. M.; Baxter, D.; Behnke, E.; Bhattacharjee, P.; Borsodi, H.; Bou-Cabo, M.; Campion, P.; Cao, G.; Chen, C. J.; Chowdhury, U.; Clark, K.; Collar, J. I.; Cooper, P. S.; Crisler, M.; Crowder, G.; Dahl, C. E.; Das, M.; Fallows, S.; Farine, J.; Felis, I.; Filgas, R.; Girard, F.; Giroux, G.; Hall, J.; Harris, O.; Hoppe, E. W.; Jin, M.; Krauss, C. B.; Laurin, M.; Lawson, I.; Leblanc, A.; Levine, I.; Lippincott, W. H.; Mamedov, F.; Maurya, D.; Mitra, P.; Nania, T.; Neilson, R.; Noble, A. J.; Olson, S.; Ortega, A.; Plante, A.; Podviyanuk, R.; Priya, S.; Robinson, A. E.; Roeder, A.; Rucinski, R.; Scallon, O.; Seth, S.; Sonnenschein, A.; Starinski, N.; Štekl, I.; Tardif, F.; Vázquez-Jáuregui, E.; Wells, J.; Wichoski, U.; Yan, Y.; Zacek, V.; Zhang, J.; PICO Collaboration

2017-06-01

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C3 F8 located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO -60 C 3F8 exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one event per month. A blind analysis of an efficiency-corrected 1167-kg day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the weakly interacting massive particle (WIMP)-proton spin-dependent cross section at 3.4 ×10-41 cm2 for a 30 -GeV c-2 WIMP, more than 1 order of magnitude improvement from previous PICO results.

Expandable Purge Chambers Would Protect Cryogenic Fittings

NASA Technical Reports Server (NTRS)

Townsend, Ivan I., III

2004-01-01

Expandable ice-prevention and cleanliness-preservation (EIP-CP) chambers have been proposed to prevent the accumulation of ice or airborne particles on quick-disconnect (QD) fittings, or on ducts or tubes that contain cryogenic fluids. In the original application for which the EIP-CP chambers were conceived, there is a requirement to be able to disconnect and reconnect the QD fittings in rapid succession. If ice were to form on the fittings by condensation and freezing of airborne water vapor on the cold fitting surfaces, the ice could interfere with proper mating of the fittings, making it necessary to wait an unacceptably long time for the ice to thaw before attempting reconnection. By keeping water vapor away from the cold fitting surfaces, the EIP-CP chambers would prevent accumulation of ice, preserving the ability to reconnect as soon as required. Basically, the role of an EIP-CP chamber would be to serve as an enclosure for a flow of dry nitrogen gas that would keep ambient air away from QD cryogenic fittings. An EIP-CP chamber would be an inflatable device made of a fabriclike material. The chamber would be attached to an umbilical plate holding a cryogenic QD fitting.

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...

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...

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...

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...

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...

Zero Power Warming (ZPW) Chamber Prototype Measurements, Barrow, Alaska, 2016

DOE Data Explorer

Shawn Serbin; Alistair Rogers; Kim Ely

2017-02-10

Data were collected during one season of prototyping associated with the development of a passive warming technology. An experimental chamber, the Zero Power Warming (ZPW) chamber, was fitted with apparatus to modulate venting of a field enclosure and enhance elevation of air temperature by solar radiation. The ZPW chamber was compared with a control chamber (Control) and an ambient open air plot (Ambient). The control chamber was identical to the ZPW chamber but lacked the apparatus necessary to modulate venting, the chamber vents in the control chamber were fixed open for the majority of the trial period. The three plots were located over Carex aquatilis growing in an area of moderately degraded permafrost. Chambers were placed on the same footprints that were used for a similar exercise in 2015 (no data) and therefore those plots had experienced some thaw and degradation prior to 2016. The following data were collected for 80 days at 1 minute intervals from within two chambers and an ambient plot: solar input, chamber venting, air temperature, relative humidity, soil temperature (at 5, 10 and 15 cm), soil moisture, downward and upward NIR.

30 CFR 56.7807 - Flushing the combustion chamber.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Flushing the combustion chamber. 56.7807 Section 56.7807 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Rotary Jet Piercing Rotary Jet Piercing § 56.7807 Flushing the combustion chamber. The combustion chamber...

30 CFR 56.7807 - Flushing the combustion chamber.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Flushing the combustion chamber. 56.7807 Section 56.7807 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Rotary Jet Piercing Rotary Jet Piercing § 56.7807 Flushing the combustion chamber. The combustion chamber...

30 CFR 56.7807 - Flushing the combustion chamber.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Flushing the combustion chamber. 56.7807 Section 56.7807 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Rotary Jet Piercing Rotary Jet Piercing § 56.7807 Flushing the combustion chamber. The combustion chamber...

21 CFR 868.5470 - Hyperbaric chamber.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 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 (§ 878...

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 (§ 878...

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 (§ 878...

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 (§ 878...

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 (§ 878...

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.

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.;

Flux Chamber Measurements of Methane Emissions and Stable Isotope Composition from an Arctic Wetland Using Field-Deployed Real-Time CRDS Vs Lab Measurements

NASA Astrophysics Data System (ADS)

Thompson, H. A.; Stern, J. C.; Graham, H. V.; Pratt, L. M.; White, J. R.

2014-12-01

The emission of CH4 from Arctic landscapes under warming climate is an important feedback in Earth's climate system. Studies of CH4 flux from Arctic wetlands have been growing in recent years, but few provide details on biogeochemical controls. Stable isotopic measurements help elucidate methane production and consumption pathways and offer important understanding about dynamics of CH4 cycling in Arctic systems. In order to demonstrate the possible instrumental approaches to measuring methane dynamics of wetlands in the Arctic, a fringing wetland of a small lake near the Russell Glacier in Southwestern Greenland was outfitted with static flux chambers and instrumented with a field-deployable Cavity Ring Down Spectrometer (CRDS) to measure real-time concentrations of CH4 and CO2 and their stable carbon isotopes. Several different wetland plant communities were included in the flux chamber experiments and field tests were conducted during several weeks in July 2014. Analytical measurements by CRDS were compared to batch samples analyzed in the laboratory using both Off-Axis Integrated Cavity Output Spectroscopy (ICOS) and Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS) with cryogenic pre-concentration. Results from flux chamber deployments will be presented and comparisons between the real-time field measurements and laboratory instrumental techniques will be evaluated.

Weld Development for Aluminum Fission Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cross, Carl Edward; Martinez, Jesse Norris

2017-05-16

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

Measurement and Compensation of BPM Chamber Motion in HLS

NASA Astrophysics Data System (ADS)

Li, J. W.; Sun, B. G.; Cao, Y.; Xu, H. L.; Lu, P.; Li, C.; Xuan, K.; Wang, J. G.

2010-06-01

Significant horizontal drifts in the beam orbit in the storage ring of HLS (Hefei Light Source) have been seen for many years. What leads to the motion of Beam Position Monitor (BPM) chamber is thermal expansion mainly caused by the synchrotron light. To monitor the BPM chamber motions for all BPMs, a BPM chamber motion measurement system is built in real-time. The raster gauges are used to measure the displacements. The results distinctly show the relation between the BPM chamber motion and the beam current. To suppress the effect of BPM chamber motion, a compensation strategy is implemented at HLS. The horizontal drifts of beam orbit have been really suppressed within 20μm without the compensation of BPM chamber motion in the runtime.

The thin-wall tube drift chamber operating in vacuum (prototype)

NASA Astrophysics Data System (ADS)

Alexeev, G. D.; Glonti, L. N.; Kekelidze, V. D.; Malyshev, V. L.; Piskun, A. A.; Potrbenikov, Yu. K.; Rodionov, V. K.; Samsonov, V. A.; Tokmenin, V. V.; Shkarovskiy, S. N.

2013-08-01

The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. "Self-centering" spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

30 CFR 57.7807 - Flushing the combustion chamber.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Flushing the combustion chamber. 57.7807... and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7807 Flushing the combustion chamber. The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be...

30 CFR 57.7807 - Flushing the combustion chamber.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Flushing the combustion chamber. 57.7807... and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7807 Flushing the combustion chamber. The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be...

30 CFR 57.7807 - Flushing the combustion chamber.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Flushing the combustion chamber. 57.7807... and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7807 Flushing the combustion chamber. The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be...

To Create Space on Earth: The Space Environment Simulation Laboratory and Project Apollo

NASA Technical Reports Server (NTRS)

Walters, Lori C.

2003-01-01

Few undertakings in the history of humanity can compare to the great technological achievement known as Project Apollo. Among those who witnessed Armstrong#s flickering television image were thousands of people who had directly contributed to this historic moment. Amongst those in this vast anonymous cadre were the personnel of the Space Environment Simulation Laboratory (SESL) at the Manned Spacecraft Center (MSC) in Houston, Texas. SESL houses two large thermal-vacuum chambers with solar simulation capabilities. At a time when NASA engineers had a limited understanding of the effects of extremes of space on hardware and crews, SESL was designed to literally create the conditions of space on Earth. With interior dimensions of 90 feet in height and a 55-foot diameter, Chamber A dwarfed the Apollo command/service module (CSM) it was constructed to test. The chamber#s vacuum pumping capacity of 1 x 10(exp -6) torr can simulate an altitude greater than 130 miles above the Earth. A "lunar plane" capable of rotating a 150,000-pound test vehicle 180 deg replicates the revolution of a craft in space. To reproduce the temperature extremes of space, interior chamber walls cool to -280F as two banks of carbon arc modules simulate the unfiltered solar light/heat of the Sun. With capabilities similar to that of Chamber A, early Chamber B tests included the Gemini modular maneuvering unit, Apollo EVA mobility unit and the lunar module. Since Gemini astronaut Charles Bassett first ventured into the chamber in 1966, Chamber B has assisted astronauts in testing hardware and preparing them for work in the harsh extremes of space.

Tuned Chamber Core Panel Acoustic Test Results

NASA Technical Reports Server (NTRS)

Schiller, Noah H.; Allen, Albert R.

2016-01-01

This report documents acoustic testing of tuned chamber core panels, which can be used to supplement the low-frequency performance of conventional acoustic treatment. The tuned chamber core concept incorporates low-frequency noise control directly within the primary structure and is applicable to sandwich constructions with a directional core, including corrugated-, truss-, and fluted-core designs. These types of sandwich structures have long, hollow channels (or chambers) in the core. By adding small holes through one of the facesheets, the hollow chambers can be utilized as an array of low-frequency acoustic resonators. These resonators can then be used to attenuate low-frequency noise (below 400 Hz) inside a vehicle compartment without increasing the weight or size of the structure. The results of this test program demonstrate that the tuned chamber core concept is effective when used in isolation or combined with acoustic foam treatments. Specifically, an array of acoustic resonators integrated within the core of the panels was shown to improve both the low-frequency absorption and transmission loss of the structure in targeted one-third octave bands.

The use of the Molecular Adsorber Coating technology to mitigate vacuum chamber contamination during Pathfinder testing for the James Webb Space Telescope

NASA Astrophysics Data System (ADS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-09-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

The Use of the Molecular Adsorber Coating Technology to Mitigate Vacuum Chamber Contamination During Pathfinder Testing for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-01-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

Monte Carlo modeling of ion chamber performance using MCNP.

PubMed

Wallace, J D

2012-12-01

Ion Chambers have a generally flat energy response with some deviations at very low (<100 keV) and very high (>2 MeV) energies. Some improvements in the low energy response can be achieved through use of high atomic number gases, such as argon and xenon, and higher chamber pressures. This work looks at the energy response of high pressure xenon-filled ion chambers using the MCNP Monte Carlo package to develop geometric models of a commercially available high pressure ion chamber (HPIC). The use of the F6 tally as an estimator of the energy deposited in a region of interest per unit mass, and the underlying assumptions associated with its use are described. The effect of gas composition, chamber gas pressure, chamber wall thickness, and chamber holder wall thicknesses on energy response are investigated and reported. The predicted energy response curve for the HPIC was found to be similar to that reported by other investigators. These investigations indicate that improvements to flatten the overall energy response of the HPIC down to 70 keV could be achieved through use of 3 mm-thick stainless steel walls for the ion chamber.

GSFC Space Simulation Laboratory Contamination Philosophy: Efficient Space Simulation Chamber Cleaning Techniques

NASA Technical Reports Server (NTRS)

Roman, Juan A.; Stitt, George F.; Roman, Felix R.

1997-01-01

This paper will provide a general overview of the molecular contamination philosophy of the Space Simulation Test Engineering Section and how the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) space simulation laboratory controls and maintains the cleanliness of all its facilities, thereby, minimizing down time between tests. It will also briefly cover the proper selection and safety precautions needed when using some chemical solvents for wiping, washing, or spraying thermal shrouds when molecular contaminants increase to unacceptable background levels.

Intercalibration of benthic flux chambers I. Accuracy of flux measurements and influence of chamber hydrodynamics [review article

NASA Astrophysics Data System (ADS)

Tengberg, A.; Stahl, H.; Gust, G.; Müller, V.; Arning, U.; Andersson, H.; Hall, P. O. J.

2004-01-01

The hydrodynamic properties and the capability to measure sediment-water solute fluxes, at assumed steady state conditions, were compared for three radically different benthic chamber designs: the “Microcosm”, the “Mississippi” and the “Göteborg” chambers. The hydrodynamic properties were characterized by mounting a PVC bottom in each chamber and measuring mixing time, diffusive boundary layer thickness (DBL thickness) shear velocity (u ∗) , and total pressure created by the water mixing. The Microcosm had the most even distribution of DBL thickness and u ∗, but the highest differential pressure at high water mixing rates. The Mississippi chamber had low differential pressures at high u ∗. The Göteborg chamber was in between the two others regarding these properties. DBL thickness and u ∗ were found to correlate according to the following empirical formula: DBL=76.18(u ∗) -0.933. Multiple flux incubations with replicates of each of the chamber types were carried out on homogenized, macrofauna-free sediments in four tanks. The degree of homogeneity was determined by calculating solute fluxes (of oxygen, silicate, phosphate and ammonium) from porewater profiles and by sampling for porosity, organic carbon and meiofauna. All these results, except meiofauna, indicated that there were no significant horizontal variations within the sediment in any of the parallel incubation experiments. The statistical evaluations also suggested that the occasional variations in meiofauna abundance did not have any influence on the measured solute fluxes. Forty-three microelectrode profiles of oxygen in the DBL and porewater were evaluated with four different procedures to calculate diffusive fluxes. The procedure presented by Berg, Risgaard-Petersen and Rysgaard, 1989 [Limnol. Oceanogr. 43, 1500] was found to be superior because of its ability to fit measured profiles accurately, and because it takes into consideration vertical zonation with different oxygen

Discharge Chamber Primary Electron Modeling Activities in Three-Dimensions

NASA Technical Reports Server (NTRS)

Steuber, Thomas J.

2004-01-01

Designing discharge chambers for ion thrusters involves many geometric configuration decisions. Various decisions will impact discharge chamber performance with respect to propellant utilization efficiency, ion production costs, and grid lifetime. These hardware design decisions can benefit from the assistance of computational modeling. Computational modeling for discharge chambers has been limited to two-dimensional codes that leveraged symmetry for interpretation into three-dimensional analysis. This paper presents model development activities towards a three-dimensional discharge chamber simulation to aid discharge chamber design decisions. Specifically, of the many geometric configuration decisions toward attainment of a worthy discharge chamber, this paper focuses on addressing magnetic circuit considerations with a three-dimensional discharge chamber simulation as a tool. With this tool, candidate discharge chamber magnetic circuit designs can be analyzed computationally to gain insight into factors that may influence discharge chamber performance such as: primary electron loss width in magnetic cusps, cathode tip position with respect to the low magnetic field volume, definition of a low magnetic field region, and maintenance of a low magnetic field region across the grid span. Corroborating experimental data will be obtained from mockup hardware tests. Initially, simulated candidate magnetic circuit designs will resemble previous successful thruster designs. To provide opportunity to improve beyond previous performance benchmarks, off-design modifications will be simulated and experimentally tested.

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…

Leaf water potentials measured with a pressure chamber.

PubMed

Boyer, J S

1967-01-01

Leaf water potentials were estimated from the sum of the balancing pressure measured with a pressure chamber and the osmotic potential of the xylem sap in leafy shoots or leaves. When leaf water potentials in yew, rhododendron, and sunflower were compared with those measured with a thermocouple psychrometer known to indicate accurate values of leaf water potential, determinations were within +/- 2 bars of the psychrometer measurements with sunflower and yew. In rhododendron. water potentials measured with the pressure chamber plus xylem sap were 2.5 bars less negative to 4 bars more negative than psychrometer measurements.The discrepancies in the rhododendron measurements could be attributed, at least in part, to the filling of tissues other than xylem with xylem sap during measurements with the pressure chamber. It was concluded that, although stem characteristics may affect the measurements, pressure chamber determinations were sufficiently close to psychrometer measurements that the pressure chamber may be used for relative measurements of leaf water potentials, especially in sunflower and yew. For accurate determinations of leaf water potential, however, pressure chamber measurements must be calibrated with a thermocouple psychrometer.

Right/left assignment in drift chambers and proportional multiwire chambers (PWC's) using induced signals

DOEpatents

Walenta, Albert H.

1979-01-01

Improved multiwire chamber having means for resolving the left/right ambiguity in the location of an ionizing event. The chamber includes a plurality of spaced parallel anode wires positioned between spaced planar cathodes. Associated with each of the anode wires are a pair of localizing wires, one positioned on either side of the anode wire. The localizing wires are connected to a differential amplifier whose output polarity is determined by whether the ionizing event occurs to the right or left of the anode wire.

Air kerma calibration factors and chamber correction values for PTW soft x-ray, NACP and Roos ionization chambers at very low x-ray energies.

PubMed

Ipe, N E; Rosser, K E; Moretti, C J; Manning, J W; Palmer, M J

2001-08-01

This paper evaluates the characteristics of ionization chambers for the measurement of absorbed dose to water using very low-energy x-rays. The values of the chamber correction factor, k(ch), used in the IPEMB 1996 code of practice for the UK secondary standard ionization chambers (PTW type M23342 and PTW type M23344), the Roos (PTW type 34001) and NACP electron chambers are derived. The responses in air of the small and large soft x-ray chambers (PTW type M23342 and PTW type M23344) and the NACP and Roos electron ionization chambers were compared. Besides the soft x-ray chambers, the NACP and Roos chambers can be used for very low-energy x-ray dosimetry provided that they are used in the restricted energy range for which their response does not change by more than 5%. The chamber correction factor was found by comparing the absorbed dose to water determined using the dosimetry protocol recommended for low-energy x-rays with that for very low-energy x-rays. The overlap energy range was extended using data from Grosswendt and Knight. Chamber correction factors given in this paper are chamber dependent, varying from 1.037 to 1.066 for a PTW type M23344 chamber, which is very different from a value of unity given in the IPEMB code. However, the values of k(ch) determined in this paper agree with those given in the DIN standard within experimental uncertainty. The authors recommend that the very low-energy section of the IPEMB code is amended to include the most up-to-date values of k(ch).

Safety shield for vacuum/pressure-chamber windows

NASA Technical Reports Server (NTRS)

Shimansky, R. A.; Spencer, R.

1980-01-01

Optically-clear shatter-resistant safety shield protects workers from implosion and explosion of vacuum and pressure windows. Plastic shield is inexpensive and may be added to vacuum chambers, pressure chambers, and gas-filling systems.

Measurement and Compensation of BPM Chamber Motion in HLS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, J. W.; Sun, B. G.; Cao, Y.

2010-06-23

Significant horizontal drifts in the beam orbit in the storage ring of HLS (Hefei Light Source) have been seen for many years. What leads to the motion of Beam Position Monitor (BPM) chamber is thermal expansion mainly caused by the synchrotron light. To monitor the BPM chamber motions for all BPMs, a BPM chamber motion measurement system is built in real-time. The raster gauges are used to measure the displacements. The results distinctly show the relation between the BPM chamber motion and the beam current. To suppress the effect of BPM chamber motion, a compensation strategy is implemented at HLS.more » The horizontal drifts of beam orbit have been really suppressed within 20{mu}m without the compensation of BPM chamber motion in the runtime.« less

Developing Cloud Chambers with High School Students

NASA Astrophysics Data System (ADS)

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

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

Liquid Engine Design: Effect of Chamber Dimensions on Specific Impulse

NASA Technical Reports Server (NTRS)

Hoggard, Lindsay; Leahy, Joe

2009-01-01

Which assumption of combustion chemistry - frozen or equilibrium - should be used in the prediction of liquid rocket engine performance calculations? Can a correlation be developed for this? A literature search using the LaSSe tool, an online repository of old rocket data and reports, was completed. Test results of NTO/Aerozine-50 and Lox/LH2 subscale and full-scale injector and combustion chamber test results were found and studied for this task. NASA code, Chemical Equilibrium with Applications (CEA) was used to predict engine performance using both chemistry assumptions, defined here. Frozen- composition remains frozen during expansion through the nozzle. Equilibrium- instantaneous chemical equilibrium during nozzle expansion. Chamber parameters were varied to understand what dimensions drive chamber C* and Isp. Contraction Ratio is the ratio of the nozzle throat area to the area of the chamber. L is the length of the chamber. Characteristic chamber length, L*, is the length that the chamber would be if it were a straight tube and had no converging nozzle. Goal: Develop a qualitative and quantitative correlation for performance parameters - Specific Impulse (Isp) and Characteristic Velocity (C*) - as a function of one or more chamber dimensions - Contraction Ratio (CR), Chamber Length (L ) and/or Characteristic Chamber Length (L*). Determine if chamber dimensions can be correlated to frozen or equilibrium chemistry.

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

Mechanisms Affecting Performance of the BaBar Resistive Plate Chambers and Searches for Remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Changguo

2003-09-19

The BaBar experiment at PEPII relies on the Instrumentation of the Flux Return (IFR) for both muon identification and KL detection. The active detector is composed of Resistive Plate Chambers (RPC's) operated in streamer mode. Since the start of operation the RPC's have suffered persistent efficiency deterioration and dark current increase problems. The ''autopsy'' of bad BaBar RPC's revealed that in many cases uncured Linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil ''stalagmites'' bridging the 2 mm gap. In this paper a possible model of this ''stalagmite'' formation andmore » its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement.« less

Growth, chamber building rate and reproduction time of Palaeonummulites venosus (Foraminifera) under natural conditions

NASA Astrophysics Data System (ADS)

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

2017-12-01

We investigated the symbiont-bearing benthic foraminifer Palaeonummulites venosus to determine the chamber building rate (CBR), test diameter increase rate (DIR), reproduction time and longevity using the `natural laboratory' approach. This is based on the decomposition of monthly obtained frequency distributions of chamber number and test diameter into normally distributed components. Test measurements were taken using MicroCT. The shift of the mean and standard deviation of component parameters during the 15-month investigation period was used to calculate Michaelis-Menten functions applied to estimate the averaged CBR and DIR under natural conditions. The individual dates of birth were estimated using the inverse averaged CBR and the inverse DIR fitted by the individual chamber number or the individual test diameter at the sampling date. Distributions of frequencies and densities (i.e., frequency divided by sediment weight) based on both CBR and DIR revealed continuous reproduction throughout the year with two peaks, a stronger one in June determined as the onset of the summer generation (generation 1) and a weaker one in November determined as the onset of the winter generation (generation 2). This reproduction scheme explains the presence of small and large specimens in the same sample. Longevity, calculated as the maximum difference in days between the individual's birth date and the sampling date, is approximately 1.5 yr, an estimation obtained by using both CBR and DIR.

Metasurfaced Reverberation Chamber.

PubMed

Sun, Hengyi; Li, Zhuo; Gu, Changqing; Xu, Qian; Chen, Xinlei; Sun, Yunhe; Lu, Shengchen; Martin, Ferran

2018-01-25

The concept of metasurfaced reverberation chamber (RC) is introduced in this paper. It is shown that by coating the chamber wall with a rotating 1-bit random coding metasurface, it is possible to enlarge the test zone of the RC while maintaining the field uniformity as good as that in a traditional RC with mechanical stirrers. A 1-bit random coding diffusion metasurface is designed to obtain all-direction backscattering under normal incidence. Three specific cases are studied for comparisons, including a (traditional) mechanical stirrer RC, a mechanical stirrer RC with a fixed diffusion metasurface, and a RC with a rotating diffusion metasurface. Simulation results show that the compact rotating diffusion metasurface can act as a stirrer with good stirring efficiency. By using such rotating diffusion metasurface, the test region of the RC can be greatly extended.

Improving mercury flux chamber measurements over water surface.

PubMed

Lanzillotra, E; Ceccarini, C; Ferrara, R

2003-07-01

A modified floating flux chamber was designed and used to measure mercury evasional fluxes in a coastal area of the Mediterranean Sea in different meteo-marine conditions during the hours of maximum insolation (PAR intensity 360-430 W m(-2)) in the summer season. The chamber has been modified providing a flap at the inlet port preventing the back-flow of air from the interior of the chamber. Results demonstrate that the modified flux chamber gives flux values noticeably higher both in rippled sea conditions (mean value 7.88 +/- 1.45 ng m(-2) h(-1)) and in rough sea conditions (mean value 21.71 +/- 2.17 ng m(-2) h(-1)) with respect to those obtained by using the unmodified chamber (respectively 5.23 +/- 0.67 and 14.15 +/- 1.03 ng m(-2) h(-1)).

In-Pile Sub-Miniature Fission Chambers Testing in BR2

NASA Astrophysics Data System (ADS)

Vermeeren, L.; Wéber, M.; Blandin, Ch.; Breaud, S.

2003-06-01

Three innovative sub-miniature fission chambers (SMFC), designed and manufactured at the Nuclear Measurement Systems Laboratory (LSMN) of CEA/Cadarache, were extensively tested in the BR2 research reactor at SCK•CEN, Mol. We present the experimental results for the (thermal) neutron sensitivity, the gamma-induced signal, the signal due to activation, the current picked up by the signal cable, the global current/voltage characteristics and the long term behaviour up to a thermal neutron fluence of 2.7·1021 n/cm2. We also compare the data with results from calculations with our FCD computer code. The onset of the saturation domain is well predicted by FCD; the neutron sensitivities can be accounted for perfectly after a refinement of the FCD model.

Technical Review of the Laboratory Biosphere Closed Ecological System Facility

NASA Astrophysics Data System (ADS)

Dempster, W.; van Thillo, M.; Alling, A.; Allen, J.; Silverstone, S.; Nelson, M.

The "Laboratory Biosphere", a new closed ecological system facility in Santa Fe, New Mexico (USA) has been constructed and became operational in May 2002. Built and operated by the Global Ecotechnics consortium (Biosphere Technologies and Biosphere Foundation with Biospheric Design Inc., and the Institute of Ecotechnics), the research apparatus for intensive crop growth, biogeochemical cycle dynamics and recycling of inedible crop biomass comprises a sealed cylindrical steel chamber and attached variable volume chamber (lung) to prevent pressures caused by the expansion and contraction of the contained air. The cylindrical growing chamber is 3.7m (12 feet) long and 3.7m (12 foot) diameter, giving an internal volume of 34 m3 (1200 ft 3 ). The two crop growth beds cover 5.5 m2, with a soil depth of 0.3m (12 inches), with 12 x 1000 watt high-pressure sodium lights capable of variable lighting of 40-70 mol per m2 per day. A small soil bed reactor in the chamber can be activated to help with metabolism of chamber trace gases. The volume of the attached variable volume chamber (lung) can range between 0-11 m3 (0-400 ft 3 ). Evapotranspired and soil leachate water are collected, combined and recycled to water the planting beds. Sampling ports enable testing of water quality of leachate, condensate and irrigation water. Visual inspection windows provide views of the entire interior and growing beds. The chamber is also outfitted with an airlock to minimize air exchange when people enter and work in the chamber. Continuous sensors include atmospheric CO2 and oxygen, temperature, humidity, soil moisture, light level and water levels in reservoirs. Both "sniffer" (air ports) and "sipper" (water ports) will enable collection of water or air samples for detailed analysis. This paper reports on the development of this new soil-based bioregenerative life support closed system apparatus and its technical challenges and capabilities.

Spatial Variation of Pressure in the Lyophilization Product Chamber Part 1: Computational Modeling.

PubMed

Ganguly, Arnab; Varma, Nikhil; Sane, Pooja; Bogner, Robin; Pikal, Michael; Alexeenko, Alina

2017-04-01

The flow physics in the product chamber of a freeze dryer involves coupled heat and mass transfer at different length and time scales. The low-pressure environment and the relatively small flow velocities make it difficult to quantify the flow structure experimentally. The current work presents the three-dimensional computational fluid dynamics (CFD) modeling for vapor flow in a laboratory scale freeze dryer validated with experimental data and theory. The model accounts for the presence of a non-condensable gas such as nitrogen or air using a continuum multi-species model. The flow structure at different sublimation rates, chamber pressures, and shelf-gaps are systematically investigated. Emphasis has been placed on accurately predicting the pressure variation across the subliming front. At a chamber set pressure of 115 mtorr and a sublimation rate of 1.3 kg/h/m 2 , the pressure variation reaches about 9 mtorr. The pressure variation increased linearly with sublimation rate in the range of 0.5 to 1.3 kg/h/m 2 . The dependence of pressure variation on the shelf-gap was also studied both computationally and experimentally. The CFD modeling results are found to agree within 10% with the experimental measurements. The computational model was also compared to analytical solution valid for small shelf-gaps. Thus, the current work presents validation study motivating broader use of CFD in optimizing freeze-drying process and equipment design.

Strip Ionization Chamber as Beam Monitor in the Proton Therapy Eye Treatment

NASA Astrophysics Data System (ADS)

Marchetto, F.; Cirio, R.; Garella, M. A.; Giordanengo, S.; Boriano, A.; Givehchi, N.; La Rosa, A.; Peroni, C.; Donetti, M.; Bourhaleb, F.; Pitta', G.; Cirrone, G. A. P.; Cuttone, G.; Raffaele, L.; Sabini, M. G.; Valastro, L.

2006-04-01

Since spring 2002, ocular pathologies have been treated in Catania at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) within a collaboration between INFN Laboratori Nazionali del Sud (LNS), Physics Department, Ophthalmology Institute, Radiology Institute of the Catania University and CSFNSM Catania. A beam line from a 62 MeV Superconducting Cyclotron is used to treat shallow tumors. The beam is conformed to the tumor shape with a passive delivery system. A detector system has been developed in collaboration with INFN-Torino to be used as real time beam monitor. The detector, placed upstream of the patient collimator, consists of two parallel plate ionization chambers with the anode segmented in strips. Each anode is made of 0.5 mm-wide 256 strips corresponding to (12.8 × 12.8) cm2 sensitive area. With the two strip ionization chambers one can measure the relevant beam parameters during treatment to probe both asymmetry and flatness. In the test carried out at CATANA the detector has been used under different and extreme beam conditions. Preliminary results are given for profiles and skewness, together with a comparison with reference detectors.

Development Radar Absorber Material using Rice Husk Carbon for Anechoic Chamber Application

NASA Astrophysics Data System (ADS)

Zulpadrianto, Z.; Yohandri, Y.; Putra, A.

2018-04-01

The developments of radar technology in Indonesia are very strategic due to the vast territory and had a high-level cloud cover more than 55% of the time. The objective of this research is to develop radar technology facility in Indonesia using local natural resources. The target of this research is to present a low cost and satisfy quality of anechoic chambers. Anechoic chamber is a space designed to avoid reflection of EM waves from outside or from within the room. The reflection coefficient of the EM wave is influenced by the medium imposed by the EM wave. In laboratory experimental research has been done the development of material radar absorber using rice husk. The rice husk is activated using HCl and KOH by stirring using a magnetic stirrer for 1 Hours. The results of rice husk activation were measured using a Vector Network Analyzer by varying the thickness of the ingredients and the concentration of the activation agent. The VNA measurement is obtained reflection coefficient of -12dB and. -6.22dB for 1M HCL and KOH at thickness 10mm, respectively.

Electromagnetic analysis of the plasma chamber of an ECR-based charge breeder

NASA Astrophysics Data System (ADS)

Galatà, A.; Patti, G.; Celona, L.; Mascali, D.; Neri, L.; Torrisi, G.

2016-02-01

The optimization of the efficiency of an ECR-based charge breeder is a twofold task: efforts must be paid to maximize the capture of the injected 1+ ions by the confined plasma and to produce high charge states to allow post-acceleration at high energies. Both tasks must be faced by studying in detail the electrons heating dynamics, influenced by the microwave-to-plasma coupling mechanism. Numerical simulations are a powerful tools for obtaining quantitative information about the wave-to-plasma interaction process: this paper presents a numerical study of the microwaves propagation and absorption inside the plasma chamber of the PHOENIX charge breeder, which the selective production of exotic species project, under construction at Legnaro National Laboratories, will adopt as charge breeder. Calculations were carried out with a commercial 3D FEM solver: first, all the resonant frequencies were determined by considering a simplified plasma chamber; then, the realistic geometry was taken into account, including a cold plasma model of increasing complexity. The results gave important information about the power absorption and losses and will allow the improvement of the plasma model to be used in a refined step of calculation reproducing the breeding process itself.

The 'Natural Laboratory', a tool for deciphering growth, lifetime and population dynamics in larger benthic foraminifera

NASA Astrophysics Data System (ADS)

Hohenegger, Johann

2015-04-01

The shells of symbiont-bearing larger benthic Foraminifera (LBF) represent the response to physiological requirements in dependence of environmental conditions. All compartments of the shell such as chambers and chamberlets accommodate the growth of the cell protoplasm and are adaptations for housing photosymbiotic algae. Investigations on the biology of LBF were predominantly based on laboratory studies. The lifetime of LBF under natural conditions is still unclear. LBF, which can build >100 chambers during their lifetime, are thought to live at least one year under natural conditions. This is supported by studies on population dynamics of eulittoral foraminifera. In species characterized by a time-restricted single reproduction period the mean size of specimens increases from small to large during lifetime simultaneously reducing individual number. This becomes more complex when two or more reproduction times are present within a one-year cycle leading to a mixture of abundant small individuals with few large specimens during the year, while keeping mean size more or less constant. This mixture is typical for most sublittoral megalospheric (gamonts or schizonts) LBF. Nothing is known on the lifetime of agamonts, the diploid asexually reproducing generation. In all hyaline LBF it is thought to be significantly longer than 1 year based on the large size and considering the mean chamber building rate of the gamont/schizonts. Observations on LBF under natural conditions have not been performed yet in the deeper sublittoral. This reflects the difficulties due to intense hydrodynamics that hinder deploying technical equipment for studies in the natural environment. Therefore, studying growth, lifetime and reproduction of sublittoral LBF under natural conditions can be performed using the so-called 'natural laboratory' in comparison with laboratory investigations. The best sampling method in the upper sublittoral from 5 to 70 m depth is by SCUBA diving. Irregular

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.

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.

Crypto-magma chambers beneath Mt. Fuji

NASA Astrophysics Data System (ADS)

Kaneko, Takayuki; Yasuda, Atsushi; Fujii, Toshitsugu; Yoshimoto, Mitsuhiro

2010-06-01

Mt. Fuji consists dominantly of basalt. A study of olivine-hosted melt-inclusions from layers of air-fall scoria, however, shows clear evidence of andesitic liquids. Whole rock compositions show a narrow range of SiO 2, but a wide range of FeO*/MgO and incompatible elements. Phenocrystic plagioclase generally shows bi-modal distributions in compositional frequency, while most olivine phenocrysts show uni-modal distribution with reverse zoning and often contain andesitic melt-inclusions. These suggest that magmas erupted from Fuji are generated through mixing between basaltic and more SiO 2-rich (often andesitic) end-members. We propose that Fuji's magmatic plumbing system consists of at least two magma chambers: a relatively deep (˜20 km) basaltic one and a relatively shallow (˜ 8-9 km) and more SiO 2-rich one. Evolved basalts with wide compositional ranges of incompatible elements are generated in the deep basaltic magma chamber by prevalent fractional crystallization of pyroxenes with olivine and calcic plagioclase at high pressure. Meanwhile basaltic magma left behind by the previous eruption in the conduit accumulates in a shallow magma chamber, and is differentiated to more SiO 2-rich composition by fractional crystallization of olivine, less-calcic plagioclase, and clinopyroxene. Shortly before a new eruption, a large amount of evolved basaltic magma containing calcic plagioclase rises from the deeper magma chamber and is mixed with the more SiO 2-rich magma in the shallow chamber, to generate the hybrid basaltic magma.

Designing an Active Target Test Projection Chamber

NASA Astrophysics Data System (ADS)

Koci, James; Tan Ahn Collaboration, Dr.; Nicolas Dixneuf Collaboration

2015-10-01

The development of instrumentation in nuclear physics is crucial for advancing our ability to measure the properties of exotic nuclei. One limitation of the use of exotic nuclei in experiment is their very low production intensities. Recently, detectors, called active-target dectectors, have been developed to address this issue. Active-target detectors use a gas medium to image charged-particle tracks that are emitted in nuclear reactions. Last semester, I designed a vacuum chamber to be used in developing Micro-Pattern Gas detectors that will upgrade the capabilities of an active-target detector called the Prototype AT-TPC. With the exterior of the chamber complete, I have now been using an electric field modeling program, Garfield, developed by CERN to design a field cage to be placed within the vacuum chamber. The field cage will be a box-like apparatus consisting of two parallel metal plates connected with a resistor chain and attached to wires wrapped between them. The cage will provide a uniform electric field within the chamber to drift electrons from nuclear reactions down to the detector in the bottom of the chamber. These signals are then amplified by a proportional counter, and the data is sent to a computer. For the long term, we would like to incorporate a Micro-Pattern Gas Detectors in the interior of the chamber and eventually use the AT-TPC to examine various nuclei. Dr. Ahn is my advising professor.

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.

Leaf Water Potentials Measured with a Pressure Chamber

PubMed Central

Boyer, J. S.

1967-01-01

Leaf water potentials were estimated from the sum of the balancing pressure measured with a pressure chamber and the osmotic potential of the xylem sap in leafy shoots or leaves. When leaf water potentials in yew, rhododendron, and sunflower were compared with those measured with a thermocouple psychrometer known to indicate accurate values of leaf water potential, determinations were within ± 2 bars of the psychrometer measurements with sunflower and yew. In rhododendron. water potentials measured with the pressure chamber plus xylem sap were 2.5 bars less negative to 4 bars more negative than psychrometer measurements. The discrepancies in the rhododendron measurements could be attributed, at least in part, to the filling of tissues other than xylem with xylem sap during measurements with the pressure chamber. It was concluded that, although stem characteristics may affect the measurements, pressure chamber determinations were sufficiently close to psychrometer measurements that the pressure chamber may be used for relative measurements of leaf water potentials, especially in sunflower and yew. For accurate determinations of leaf water potential, however, pressure chamber measurements must be calibrated with a thermocouple psychrometer. PMID:16656476

Structural analysis of cylindrical thrust chambers, volume 1

NASA Technical Reports Server (NTRS)

Armstrong, W. H.

1979-01-01

Life predictions of regeneratively cooled rocket thrust chambers are normally derived from classical material fatigue principles. The failures observed in experimental thrust chambers do not appear to be due entirely to material fatigue. The chamber coolant walls in the failed areas exhibit progressive bulging and thinning during cyclic firings until the wall stress finally exceeds the material rupture stress and failure occurs. A preliminary analysis of an oxygen free high conductivity (OFHC) copper cylindrical thrust chamber demonstrated that the inclusion of cumulative cyclic plastic effects enables the observed coolant wall thinout to be predicted. The thinout curve constructed from the referent analysis of 10 firing cycles was extrapolated from the tenth cycle to the 200th cycle. The preliminary OFHC copper chamber 10-cycle analysis was extended so that the extrapolated thinout curve could be established by performing cyclic analysis of deformed configurations at 100 and 200 cycles. Thus the original range of extrapolation was reduced and the thinout curve was adjusted by using calculated thinout rates at 100 and 100 cycles. An analysis of the same underformed chamber model constructed of half-hard Amzirc to study the effect of material properties on the thinout curve is included.

Stainless Steel Vacuum Chamber for Scanning Transmission X-ray Microsopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kilcoyne, Arthur L.

The stainless steel chamber was specifically conceived and designed for housing an interferometer controlled scanning transmission x-ray microscope (STXM). The construction of the chamber is such that internal components of the microscope rest within the chamber and are fixed to a 4 inch stainless steel belly band. The integral and most important part of the chamber is the belly band, which serves to isolate high frequency vibrations (e.g., floor surroundings, people traffic) from the sensitive measurements performed using the microscope. In addition, the chamber effectively acts as a sound barrier to the nanometer measurements conducted within. The assembled chamber (andmore » microscope) are readily adjustable at the micron level using strut members external to the chamber but fixed to the belly band and a stand made of polymer concreate.« less

Evaluation of Vortex Chamber Concepts for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Trinh, Huu Phuoc; Knuth, Williams; Michaels, Scott; Turner, James E. (Technical Monitor)

2000-01-01

Rocket-based combined-cycle engines (RBBC) being considered at NASA for future generation launch vehicles feature clusters of small rocket thrusters as part of the engine components. Depending on specific RBBC concepts, these thrusters may be operated at various operating conditions including power level and/or propellant mixture ratio variations. To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for the subject cycle engine application. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concepts not only offer the system simplicity but they also would enhance the combustion performance. The test results showed that the chamber performance was markedly high even at a low chamber length-to- diameter ratio (L/D). This incentive can be translated to a convenience in the thrust chamber packaging.

Chamber Specific Gene Expression Landscape of the Zebrafish Heart

PubMed Central

Singh, Angom Ramcharan; Sivadas, Ambily; Sabharwal, Ankit; Vellarikal, Shamsudheen Karuthedath; Jayarajan, Rijith; Verma, Ankit; Kapoor, Shruti; Joshi, Adita; Scaria, Vinod; Sivasubbu, Sridhar

2016-01-01

The organization of structure and function of cardiac chambers in vertebrates is defined by chamber-specific distinct gene expression. This peculiarity and uniqueness of the genetic signatures demonstrates functional resolution attributed to the different chambers of the heart. Altered expression of the cardiac chamber genes can lead to individual chamber related dysfunctions and disease patho-physiologies. Information on transcriptional repertoire of cardiac compartments is important to understand the spectrum of chamber specific anomalies. We have carried out a genome wide transcriptome profiling study of the three cardiac chambers in the zebrafish heart using RNA sequencing. We have captured the gene expression patterns of 13,396 protein coding genes in the three cardiac chambers—atrium, ventricle and bulbus arteriosus. Of these, 7,260 known protein coding genes are highly expressed (≥10 FPKM) in the zebrafish heart. Thus, this study represents nearly an all-inclusive information on the zebrafish cardiac transcriptome. In this study, a total of 96 differentially expressed genes across the three cardiac chambers in zebrafish were identified. The atrium, ventricle and bulbus arteriosus displayed 20, 32 and 44 uniquely expressing genes respectively. We validated the expression of predicted chamber-restricted genes using independent semi-quantitative and qualitative experimental techniques. In addition, we identified 23 putative novel protein coding genes that are specifically restricted to the ventricle and not in the atrium or bulbus arteriosus. In our knowledge, these 23 novel genes have either not been investigated in detail or are sparsely studied. The transcriptome identified in this study includes 68 differentially expressing zebrafish cardiac chamber genes that have a human ortholog. We also carried out spatiotemporal gene expression profiling of the 96 differentially expressed genes throughout the three cardiac chambers in 11 developmental stages and 6

Laboratory simulation of space plasma phenomena*

NASA Astrophysics Data System (ADS)

Amatucci, B.; Tejero, E. M.; Ganguli, G.; Blackwell, D.; Enloe, C. L.; Gillman, E.; Walker, D.; Gatling, G.

2017-12-01

Laboratory devices, such as the Naval Research Laboratory's Space Physics Simulation Chamber, are large-scale experiments dedicated to the creation of large-volume plasmas with parameters realistically scaled to those found in various regions of the near-Earth space plasma environment. Such devices make valuable contributions to the understanding of space plasmas by investigating phenomena under carefully controlled, reproducible conditions, allowing for the validation of theoretical models being applied to space data. By working in collaboration with in situ experimentalists to create realistic conditions scaled to those found during the observations of interest, the microphysics responsible for the observed events can be investigated in detail not possible in space. To date, numerous investigations of phenomena such as plasma waves, wave-particle interactions, and particle energization have been successfully performed in the laboratory. In addition to investigations such as plasma wave and instability studies, the laboratory devices can also make valuable contributions to the development and testing of space plasma diagnostics. One example is the plasma impedance probe developed at NRL. Originally developed as a laboratory diagnostic, the sensor has now been flown on a sounding rocket, is included on a CubeSat experiment, and will be included on the DoD Space Test Program's STP-H6 experiment on the International Space Station. In this presentation, we will describe several examples of the laboratory investigation of space plasma waves and instabilities and diagnostic development. *This work supported by the NRL Base Program.

Chamber study of PCB emissions from caulking materials and light ballasts.

PubMed

Liu, Xiaoyu; Guo, Zhishi; Krebs, Kenneth A; Stinson, Rayford A; Nardin, Joshua A; Pope, Robert H; Roache, Nancy F

2015-10-01

The emissions of polychlorinated biphenyl (PCB) congeners from thirteen caulk samples were tested in a micro-chamber system. Twelve samples were from PCB-contaminated buildings and one was prepared in the laboratory. Nineteen light ballasts collected from buildings that represent 13 different models from five manufacturers were tested in 53-L environmental chambers. The rates of PCB congener emissions from caulking materials and light ballasts were determined. Several factors that may have affected the emission rates were evaluated. The experimentally determined emission factors showed that, for a given PCB congener, there is a linear correlation between the emission factor and the concentration of the PCB congener in the source. Furthermore, the test results showed that an excellent log-linear correlation exists between the normalized emission factor and the vapor pressure (coefficient of determination, r(2)⩾0.8846). The PCB congener emissions from ballasts at or near room temperature were relatively low with or without electrical load. However, the PCB congener emission rates increased significantly as the temperature increased. The results of this research provide new data and models for ranking the primary sources of PCBs and supports the development and refinement of exposure assessment models for PCBs. Published by Elsevier Ltd.

Gas-phase Precursors to Anthropogenic SOA: Using the MCM to Probe Detailed Observations of Aromatic Photo-oxidation

NASA Astrophysics Data System (ADS)

Rickard, A. R.; Wyche, K. P.; Metzger, A.; Monks, P. S.; Ellis, A. M.; Baltensperger, U.; Pilling, M. J.; Jenkin, M. E.

2008-12-01

The formation of photochemical ozone and particulate matter are major priorities in the determination of European air quality policies. Predictions of the future state of the atmosphere and the development of appropriate mitigation strategies rely on models, which necessarily incorporate chemistry. The Master Chemical Mechanism (MCM, http://mcm.leeds.ac.uk/MCM) is a near-explicit chemical mechanism originally conceived to model ozone formation in Europe but now also employed as a benchmark mechanism in a wide variety of applications where chemical detail is required. The MCM currently describes the detailed gas- phase tropospheric degradation of a 135 primary emitted volatile organic compounds (VOCs) leading to a mechanism containing ca. 5900 species and 13500 reactions. In order that the MCM continues to be a state-of-the-art resource for the atmospheric science community it resides under a constant regime of evaluation, development and improvement. Individual VOC photochemical mechanisms are evaluated using data obtained, under a variety of atmospheric conditions, from highly instrumented smog chambers. Smog chamber experiments are crucial, not only for mechanism evaluation, but also for mechanism development. Findings obtained from combined model and chamber studies can additionally provide key insight for guiding the directions of future laboratory experiments. Recently, the MCM was updated to MCMv3.1 in order to take into account recent advancements in the understanding of aromatic photo-oxidation, an important class of anthropogenic VOCs. As well as constituting precursors to secondary organic aerosol (SOA), aromatics generally have high photochemical ozone creation potentials (POCPs) and hence contribute significantly towards tropospheric ozone formation. In the work presented, a detailed gas-phase photochemical chamber box model, incorporating the MCMv3.1 degradation mechanism for 1,3,5-trimethylbenzene (TMB), has been used to simulate data measured during

Drift chambers on the basis of Mylar tube blocks

NASA Astrophysics Data System (ADS)

Budagov, Yu.; Chirikov-Zorin, I.; Golovanov, L.; Khazins, D.; Kuritsin, A.; Pukhov, O.; Zhukov, V.

1993-06-01

Prototypes of drift chambers constructed of Mylar tube blocks were tested. The purpose of developing tube blocks technology was to create long chambers (up to 3-4 m). Counting and drift characteristics of the chambers for different values of the gas pressure and different diameters of sense wires are presented. The lifetime of the chambers is determined. A photoeffect in the visible spectrum on the surface of the thin film aluminium cathode, which covers the Mylar tubes was observed.

Effect of primary iris and ciliary body cyst on anterior chamber angle in patients with shallow anterior chamber*

PubMed Central

Wang, Bing-hong; Yao, Yu-feng

2012-01-01

Objective: To evaluate the prevalence of primary iris and/or ciliary body cysts in eyes with shallow anterior chamber and their effect on the narrowing of the anterior chamber angle. Methods: Among the general physical check-up population, subjects with shallow anterior chambers, as judged by van Herick technique, were recruited for further investigation. Ultrasound biomicroscope (UBM) was used to detect and measure the cysts located in the iris and/or ciliary body, the anterior chamber depth (ACD), the angle opening distance at 500 μm (AOD500), and the trabecular-iris angle (TIA). A-scan ultrasonography was used to measure the ocular biometry, including lens thickness, axial length, lens/axial length factor (LAF), and relative lens position (RLP). The effect of the cyst on narrowing the corresponding anterior chamber angle and the entire angle was evaluated by the UBM images, ocular biometry, and gonioscopic grading. The eye with unilateral cyst was compared with the eye without the cyst for further analysis. Results: Among the 727 subjects with shallow anterior chamber, primary iris and ciliary body cysts were detected in 250 (34.4%) patients; among them 96 (38.4%) patients showed unilateral single cyst, 21 (8.4%) patients had unilateral double cysts, and 42 (16.8%) patients manifested unilateral multiple and multi-quadrants cysts. Plateau iris configuration was found in 140 of 361 (38.8%) eyes with cysts. The mean size of total cysts was (0.6547±0.2319) mm. In evaluation of the effect of the cyst size and location on narrowing the corresponding angle to their position, the proportion of the cysts causing corresponding angle narrowing or closure among the cysts larger than 0.8 mm (113/121, 93.4%) was found to be significantly higher than that of the cysts smaller than 0.8 mm (373/801, 46.6%), and a significant higher proportion was also found in the cysts located at iridociliary sulcus (354/437, 81.0%) than in that at the pars plicata (131/484, 27.1%). In

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…

Inhalable Microorganisms in Beijing’s PM2.5 and PM10 Pollutants during a Severe Smog Event

PubMed Central

2014-01-01

Particulate matter (PM) air pollution poses a formidable public health threat to the city of Beijing. Among the various hazards of PM pollutants, microorganisms in PM2.5 and PM10 are thought to be responsible for various allergies and for the spread of respiratory diseases. While the physical and chemical properties of PM pollutants have been extensively studied, much less is known about the inhalable microorganisms. Most existing data on airborne microbial communities using 16S or 18S rRNA gene sequencing to categorize bacteria or fungi into the family or genus levels do not provide information on their allergenic and pathogenic potentials. Here we employed metagenomic methods to analyze the microbial composition of Beijing’s PM pollutants during a severe January smog event. We show that with sufficient sequencing depth, airborne microbes including bacteria, archaea, fungi, and dsDNA viruses can be identified at the species level. Our results suggested that the majority of the inhalable microorganisms were soil-associated and nonpathogenic to human. Nevertheless, the sequences of several respiratory microbial allergens and pathogens were identified and their relative abundance appeared to have increased with increased concentrations of PM pollution. Our findings may serve as an important reference for environmental scientists, health workers, and city planners. PMID:24456276

Study on optimization of multiionization-chamber system for BNCT.

PubMed

Fujii, T; Tanaka, H; Maruhashi, A; Ono, K; Sakurai, Y

2011-12-01

In order to monitor stability of doses from the four components such as thermal, epi-thermal, fast neutron and gamma-ray during BNCT irradiation, we are developing a multiionization-chamber system. This system is consisted of four kinds of ionization chamber, which have specific sensitivity for each component, respectively. Since a suitable structure for each chamber depends on the energy spectrum of the irradiation field, the optimization study of the chamber structures for the epi-thermal neutron beam of cyclotron-based epi-thermal neutron source (C-BENS) was performed by using a Monte Carlo simulation code "PHITS" and suitable chamber-structures were determined. Copyright © 2011 Elsevier Ltd. All rights reserved.

Basic Aerodynamics of Combustion Chambers,

DTIC Science & Technology

1981-05-20

engineering circles, the trend in the design of new tyres of combustion chambers is to combine the use of aerodynamics , ;he science of heat transfer and...7. FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AF8 ON F/6 21/2 BASIC AERODYNAMICS OF COMBUSTION CHAMBERS,(U) MAY 81 N HUANG UNCLASSIFIED FTD-ID(RS)T...160󈨔 NL so EEEEEE 0hEEEEEEmollllmmlllll mEImmmmmEEE mEEEEEmmEEmmmE IilillilillEEE FTD-1D(RS)T-1684-80 FOREIGN TECHNOLOGY DIVISION BASIC AERODYNAMICS CF

Ultra-low mass drift chambers

NASA Astrophysics Data System (ADS)

Assiro, R.; Cappelli, L.; Cascella, M.; De Lorenzis, L.; Grancagnolo, F.; Ignatov, F.; L'Erario, A.; Maffezzoli, A.; Miccoli, A.; Onorato, G.; Perillo, M.; Piacentino, G.; Rella, S.; Rossetti, F.; Spedicato, M.; Tassielli, G.; Zavarise, G.

2013-08-01

We present a novel low mass drift chamber concept, developed in order to fulfill the stringent requirements imposed by the experiments for extremely rare processes, which require high resolutions (order of 100-200 keV/c) for particle momenta in a range (50-100 MeV/c) totally dominated by the multiple scattering contribution. We describe a geometry optimization procedure and a new wiring strategy with a feed-through-less wire anchoring system developed and tested on a drift chamber prototype under completion at INFN-Lecce .

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.

Application of Chaboche Model in Rocket Thrust Chamber Analysis

NASA Astrophysics Data System (ADS)

Asraff, Ahmedul Kabir; Suresh Babu, Sheela; Babu, Aneena; Eapen, Reeba

2017-06-01

Liquid Propellant Rocket Engines are commonly used in space technology. Thrust chamber is one of the most important subsystems of a rocket engine. The thrust chamber generates propulsive thrust force for flight of the rocket by ejection of combustion products at supersonic speeds. Often double walled construction is employed for these chambers. The thrust chamber investigated here has its hot inner wall fabricated out of a high thermal conductive material like copper alloy and outer wall made of stainless steel. Inner wall is subjected to high thermal and pressure loads during operation of engine due to which it will be in the plastic regime. Main reasons for the failure of such chambers are fatigue in the plastic range (called as low cycle fatigue since the number of cycles to failure will be low in plastic range), creep and thermal ratcheting. Elasto plastic material models are required to simulate the above effects through a cyclic stress analysis. This paper gives the details of cyclic stress analysis carried out for the thrust chamber using different plasticity model combinations available in ANSYS (Version 15) FE code. The best model among the above is applied in the cyclic stress analysis of two dimensional (plane strain and axisymmetric) and three dimensional finite element models of thrust chamber. Cyclic life of the chamber is calculated from stress-strain graph obtained from above analyses.

Evaluation of oxide-coated iridium-rhenium chambers

NASA Astrophysics Data System (ADS)

Reed, Brian D.

1994-03-01

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

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

The Evolution and Development of Cephalopod Chambers and Their Shape

PubMed Central

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

2016-01-01

The Ammonoidea is a group of extinct cephalopods ideal to study evolution through deep time. The evolution of the planispiral shell and complexly folded septa in ammonoids has been thought to have increased the functional surface area of the chambers permitting enhanced metabolic functions such as: chamber emptying, rate of mineralization and increased growth rates throughout ontogeny. Using nano-computed tomography and synchrotron radiation based micro-computed tomography, we present the first study of ontogenetic changes in surface area to volume ratios in the phragmocone chambers of several phylogenetically distant ammonoids and extant cephalopods. Contrary to the initial hypothesis, ammonoids do not possess a persistently high relative chamber surface area. Instead, the functional surface area of the chambers is higher in earliest ontogeny when compared to Spirula spirula. The higher the functional surface area the quicker the potential emptying rate of the chamber; quicker chamber emptying rates would theoretically permit faster growth. This is supported by the persistently higher siphuncular surface area to chamber volume ratio we collected for the ammonite Amauroceras sp. compared to either S. spirula or nautilids. We demonstrate that the curvature of the surface of the chamber increases with greater septal complexity increasing the potential refilling rates. We further show a unique relationship between ammonoid chamber shape and size that does not exist in S. spirula or nautilids. This view of chamber function also has implications for the evolution of the internal shell of coleoids, relating this event to the decoupling of soft-body growth and shell growth. PMID:26963712

The Evolution and Development of Cephalopod Chambers and Their Shape.

PubMed

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

2016-01-01

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

CONTINUOUSLY SENSITIVE BUBBLE CHAMBER

DOEpatents

Good, R.H.

1959-08-18

A radiation detector of the bubble chamber class is described which is continuously sensitive and which does not require the complex pressure cycling equipment characteristic of prior forms of the chamber. The radiation sensitive element is a gas-saturated liquid and means are provided for establishing a thermal gradient across a region of the liquid. The gradient has a temperature range including both the saturation temperature of the liquid and more elevated temperatures. Thus a supersaturated zone is created in which ionizing radiations may give rise to visible gas bubbles indicative of the passage of the radiation through the liquid. Additional means are provided for replenishing the supply of gas-saturated liquid to maintaincontinuous sensitivity.

Application of the Ta liner technique to produce Ca beams at INFN-Legnaro National Laboratories (INFN-LNL)

NASA Astrophysics Data System (ADS)

Galatà, A.; Sattin, M.; Manzolaro, M.; Martini, D.; Facco, A.; Tinschert, K.; Spaedtke, P.; Lang, R.; Kulevoy, T.

2014-02-01

The ECR ion sources are able to produce a wide variety of highly charged metallic ion beams thanks to the development of different techniques (ovens, sputtering, direct insertion, metal ions from volatile compounds (MIVOC)). In the case of the ovens, the sticking of the hot vapors on the surface of the plasma chamber leads to high material consumption rates. For elements like Ca, a tantalum liner inserted inside the chamber can be used to limit this phenomenon. The modeling of temperature distribution inside the chamber with and without the liner was carried out with COMSOL-multiphysics code. Results of simulation and the comparison with experiments performed at INFN-Legnaro National Laboratories with Ca beams are discussed.

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)

Liquid rocket engine fluid-cooled combustion chambers

NASA Technical Reports Server (NTRS)

1972-01-01

A monograph on the design and development of fluid cooled combustion chambers for liquid propellant rocket engines is presented. The subjects discussed are (1) regenerative cooling, (2) transpiration cooling, (3) film cooling, (4) structural analysis, (5) chamber reinforcement, and (6) operational problems.

Optimization of a vacuum chamber for vibration measurements.

PubMed

Danyluk, Mike; Dhingra, Anoop

2011-10-01

A 200 °C high vacuum chamber has been built to improve vibration measurement sensitivity. The optimized design addresses two significant issues: (i) vibration measurements under high vacuum conditions and (ii) use of design optimization tools to reduce operating costs. A test rig consisting of a cylindrical vessel with one access port has been constructed with a welded-bellows assembly used to seal the vessel and enable vibration measurements in high vacuum that are comparable with measurements in air. The welded-bellows assembly provides a force transmissibility of 0.1 or better at 15 Hz excitation under high vacuum conditions. Numerical results based on design optimization of a larger diameter chamber are presented. The general constraints on the new design include material yield stress, chamber first natural frequency, vibration isolation performance, and forced convection heat transfer capabilities over the exterior of the vessel access ports. Operating costs of the new chamber are reduced by 50% compared to a preexisting chamber of similar size and function.

Multi-chamber nucleic acid amplification and detection device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dugan, Lawrence

A nucleic acid amplification and detection device includes an amplification cartridge with a plurality of reaction chambers for containing an amplification reagent and a visual detection reagent, and a plurality of optically transparent view ports for viewing inside the reaction chambers. The cartridge also includes a sample receiving port which is adapted to receive a fluid sample and fluidically connected to distribute the fluid sample to the reaction chamber, and in one embodiment, a plunger is carried by the cartridge for occluding fluidic communication to the reaction chambers. The device also includes a heating apparatus having a heating element whichmore » is activated by controller to generate heat when a trigger event is detected. The heating apparatus includes a cartridge-mounting section which positioned a cartridge in thermal communication with the heating element so that visual changes to the contents of the reaction chambers are viewable through the view ports.« less

Thermohydrodynamic model: Hydrothermal system, shallowly seated magma chamber

NASA Astrophysics Data System (ADS)

Kiryukhin, A. V.

1985-02-01

The results of numerical modeling of heat exchange in the Hawaiian geothermal reservoir demonstrate the possibility of appearance of a hydrothermal system over a magma chamber. This matter was investigated in hydrothermal system. The equations for the conservation of mass and energy are discussed. Two possible variants of interaction between the magma chamber and the hydrothermal system were computated stationary dry magma chamber and dry magma chamber changing volume in dependence on the discharge of magma and taking into account heat exchange with the surrounding rocks. It is shown that the thermal supplying of the hydrothermal system can be ensured by the extraction of heat from a magma chamber which lies at a depth of 3 km and is melted out due to receipt of 40 cubic km of basalt melt with a temperature of 1,300 C. The initial data correspond with computations made with the model to the temperature values in the geothermal reservoir and a natural heat transfer comparable with the actually observed values.

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

30 CFR 77.303 - Hot gas inlet chamber dropout doors.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet chamber...

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

NASA Technical Reports Server (NTRS)

1976-01-01

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

Space Simulation Chamber Rescues Water Damaged Books.

ERIC Educational Resources Information Center

American School and University, 1981

1981-01-01

More than 4,000 valuable water-damaged books were restored by using a space-simulation chamber at the Lockheed Missile and Space Company. It was the fifth time that the chamber has been used for the restoration of valuable books and documents. (Author/MLF)

Titanium wound chambers for wound healing research.

PubMed

Nuutila, Kristo; Singh, Mansher; Kruse, Carla; Philip, Justin; Caterson, Edward J; Eriksson, Elof

2016-11-01

Standardized and reproducible animal models are crucial in medical research. Rodents are commonly used in wound healing studies since, they are easily available, affordable and simple to handle and house. However, the most significant limitation of rodent models is that the wounds heal by contraction while in humans the primary mechanisms of healing are reepithelialization and granulation tissue formation. The robust contraction results in faster wound closure that complicates the reproducibility of rodent studies in clinical trials. We have developed a titanium wound chamber for rodent wound healing research. The chamber is engineered from two pieces of titanium and is placed transcutaneously on the dorsum of a rodent. The chamber inhibits wound contraction and provides a means for controlled monitoring and sampling of the wound environment in vivo with minimal foreign body reaction. This technical report introduces two modalities utilizing the titanium chambers in rats: (1) Wound in a skin island model and, (2) Wound without skin model. Here, we demonstrate in rats how the "wound in a skin island model" slows down wound contraction and how the "wound without skin" model completely prevents the closure. The titanium wound chamber provides a reproducible standardized models for wound healing research in rodents. © 2016 by the Wound Healing Society.

21 CFR 878.5650 - Topical oxygen chamber for extremities.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Topical oxygen chamber for extremities. 878.5650... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Therapeutic Devices § 878.5650 Topical oxygen chamber for extremities. (a) Identification. A topical oxygen chamber for extremities is a device intended...

21 CFR 878.5650 - Topical oxygen chamber for extremities.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Topical oxygen chamber for extremities. 878.5650... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Therapeutic Devices § 878.5650 Topical oxygen chamber for extremities. (a) Identification. A topical oxygen chamber for extremities is a device intended...

DISCOVER-AQ Airborne Measurements Quantify How Satellite-Retrievable Becomes Health-Relevant: The Example Of Smog And Its Production

NASA Astrophysics Data System (ADS)

Esswein, R. F.; Chatfield, R. B.; Crawford, J. H.; Weinheimer, A. J.; Fried, A.; Barrick, J. D.

2012-12-01

Unusually rich information about health-relevant surface smog pollution may be expected from developing multi-wavelength retrievals from space, e.g., in upcoming missions being planned by the United States ("GEO-CAPE") and by European and Asian agencies. The key is that ozone and its precursors are vertically correlated in layers that can be retrieved, and that situation-to-situation variation is more important than small local spatial variations. Variations in relationships are understood in terms of simple weather principles such as subsidence and repeating local circulation features. BACKGROUND: Near-surface pollution is one of the most challenging problems for Earth observations from space. Near- surface information must be inferred from column-integrated quantities obtained by passive remote sensing from nadir-looking satellite instruments. NASA has undertaken a major five-year experimental mission to investigate air pollution on the 1- to 100-km urban/regional scale. The mission concept involved Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality, generally known better by its acronym DISCOVER-AQ. A major goal is to understand the usefulness of and best methodologies for satellite remote sensing data. The DISCOVER-AQ airborne study repeatedly made spirals over various urban, industrial, transportation, and rural sites in detail around the Baltimore-Washington area in July, 2011. We compare mixing ratios appropriately averaged over a 0.2-3 km altitude ("Retrievable") and those measured at the bottom of the spirals, 0.2-0.5 km, the "Relevant". The "Retrievable" layer 0.2-3 km. was set by GEO-CAPE remote- sensing sensitivity analyses for ozone [Natraj et al., Atmos. Environ., 2011]. Correlations were quite good, ca. 0.9. Retrieved-relevant correlations for O3 were determined mostly by synoptic conditions. Comparisons for NO2 and HCHO mixing ratio (= m.r.) and especially log(m.r.) are affected by

Efficacy, Safety, and Preparation of Standardized Parenteral Nutrition Regimens: Three-Chamber Bags vs Compounded Monobags-A Prospective, Multicenter, Randomized, Single-Blind Clinical Trial.

PubMed

Yu, Jianchun; Wu, Guohao; Tang, Yun; Ye, Yingjiang; Zhang, Zhongtao

2017-08-01

Parenteral nutrition (PN) covering the need for carbohydrates, amino acids, and lipids can either be compounded from single nutrients or purchased as an industrially manufactured ready-to-use regimen. This study compares a commercially available 3-chamber bag (study group) with a conventionally compounded monobag regarding nutrition efficacy, safety, and regimen preparation time. This prospective, randomized, single-blind study was conducted at 5 Chinese hospitals from October 2010-October 2011. Postsurgical patients requiring PN for at least 6 days were randomly assigned to receive the study or control regimen. Plasma concentrations of prealbumin and C-reactive protein (CRP), regimen preparation time, length of hospital stay (LOS), 30-day mortality, safety laboratory parameters, and adverse events (AEs) were recorded. In total, 240 patients (121 vs 119 in study and control groups) participated in this study. Changes in prealbumin concentrations during nutrition support (Δ Prealb(StudyGroup) = 2.65 mg/dL, P < .001 vs Δ Prealb(ControlGroup) = 0.27 mg/dL, P = .606) and CRP values were comparable. Regimen preparation time was significantly reduced in the study group by the use of 3-chamber bags (t (StudyGroup) = 4.90 ± 4.41 minutes vs t (ControlGroup) = 12.13 ± 5.62 minutes, P < .001). No differences were detected for LOS, 30-day mortality, safety laboratory parameters, and postoperative AEs (37 vs 38 in study and control groups). The PN regimen provided by the 3-chamber bag was comparable to the compounded regimen and safe in use. Time savings during regimen preparation indicates that use of 3-chamber bags simplifies the process of regimen preparation.