Science.gov

Sample records for air infiltration rate

  1. Measuring Infiltration Rates in Homes as a Basis for Understanding Indoor Air Quality

    NASA Astrophysics Data System (ADS)

    Jerz, G. G.; Lamb, B. K.; Pressley, S. N.; O'Keeffe, P.; Fuchs, M.; Kirk, M.

    2015-12-01

    Infiltration rates, or the rate of air exchange, of houses are important to understand because ventilation can be a dominate factor in determining indoor air quality. There are chemicals that are emitted from surfaces or point sources inside the home which are harmful to humans; these chemicals come from various objects including furniture, cleaning supplies, building materials, gas stoves, and the surrounding environment. The use of proper ventilation to cycle cleaner outdoor air into the house can be crucial for maintaining healthy living conditions in the home. At the same time, there can also be outdoor pollutants which infiltrate the house and contribute to poor indoor air quality. In either case, it is important to determine infiltration rates as a function of outdoor weather conditions, the house structure properties and indoor heating and cooling systems. In this work, the objective is to measure ventilation rates using periodic releases of a tracer gas and measuring how quickly the tracer concentration decays. CO2 will be used as the tracer gas because it is inert and harmless at low levels. An Arduino timer is connected to a release valve which controls the release of 9.00 SLPM of CO2 into the uptake vent within the test home. CO2 will be released until there is at least a 200 to 300 ppm increase above ambient indoor levels. Computers with CO2 sensors and temperature/pressure sensors attached will be used to record data from different locations within the home which will continuously record data up to a week. The results from these periodic ventilation measurements will be analyzed with respect to outdoor wind and temperature conditions and house structure properties. The data will be used to evaluate an established indoor air quality model.

  2. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration... gain due to infiltration as much as possible without impinging on health and comfort and within...

  3. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration... gain due to infiltration as much as possible without impinging on health and comfort and within...

  4. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration... gain due to infiltration as much as possible without impinging on health and comfort and within...

  5. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration... gain due to infiltration as much as possible without impinging on health and comfort and within...

  6. On the impact of entrapped air in infiltration under ponding conditions: Part a: Preferential air flow path effects on infiltration

    NASA Astrophysics Data System (ADS)

    Weisbord, N.; Mizrahi, G.; Furman, A.

    2015-12-01

    Entrapped air effects on infiltration under ponding conditions could be important for massive infiltration of managed aquifer recharge or soil aquifer treatment. Earlier studies found that under ponding conditions air could reduce infiltration by 70-90%. Most studies have dealt with entrapped air effects when soil surface topography is flat. The objective of this study is to investigate the effects of: (1) irregular surface topography on preferential air flow path development; (2) preferential air flow path on infiltration; and (3) hydraulic head on infiltration when air is trapped. Column experiments were used to investigate these particular effects. A 140 cm deep and 30 cm wide column packed with silica sand was used under two boundary conditions: in the first, air can only escape vertically upward through the soil surface; in the second, air is free to escape. The surface was flooded with 13 liters of water, with ponding depth decreasing with time. Two soil surface conditions were tested: flat surface and irregular. It was found that in irregular surfaces, stable air flow through preferential paths was developed in the high altitude zones. Flat surface topography caused unstable air flow through random paths. Comparison between irregular and flat surface topography showed that the entrapped air pressure was lower and the infiltration rate was about 40% higher in the irregular surface topography than in the flat surface topography. No difference of infiltration rate between flat and irregular surface topography was observed when air was free to escape along the infiltration path. It was also found that at the first stage of infiltration, higher hydraulic heads caused higher entrapped air pressures and lower infiltration rates. In contrast, higher hydraulic head results in higher infiltration rate, when air was free to escape. Our results suggest that during ponding conditions: (1) preferential air flow paths develop at high surface zones of irregular topography

  7. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration...-to-ceiling and wall-to-floor connections shall be caulked or otherwise sealed. When walls...

  8. Perfluorocarbon tracer method for air-infiltration measurements

    DOEpatents

    Dietz, R.N.

    1982-09-23

    A method of measuring air infiltration rates suitable for use in rooms of homes and buildings comprises the steps of emitting perfluorocarbons in the room to be measured, sampling the air containing the emitted perfluorocarbons over a period of time, and analyzing the samples at a laboratory or other facility.

  9. Characterizing Heterogeneity in Infiltration Rates During Managed Aquifer Recharge.

    PubMed

    Mawer, Chloe; Parsekian, Andrew; Pidlisecky, Adam; Knight, Rosemary

    2016-11-01

    Infiltration rate is the key parameter that describes how water moves from the surface into a groundwater aquifer during managed aquifer recharge (MAR). Characterization of infiltration rate heterogeneity in space and time is valuable information for MAR system operation. In this study, we utilized fiber optic distributed temperature sensing (FO-DTS) observations and the phase shift of the diurnal temperature signal between two vertically co-located fiber optic cables to characterize infiltration rate spatially and temporally in a MAR basin. The FO-DTS measurements revealed spatial heterogeneity of infiltration rate: approximately 78% of the recharge water infiltrated through 50% of the pond bottom on average. We also introduced a metric for quantifying how the infiltration rate in a recharge pond changes over time, which enables FO-DTS to be used as a method for monitoring MAR and informing maintenance decisions. By monitoring this metric, we found high-spatial variability in how rapidly infiltration rate changed during the test period. We attributed this variability to biological pore clogging and found a relationship between high initial infiltration rate and the most rapid pore clogging. We found a strong relationship (R(2)  = 0.8) between observed maximum infiltration rates and electrical resistivity measurements from electrical resistivity tomography data taken in the same basin when dry. This result shows that the combined acquisition of DTS and ERT data can improve the design and operation of a MAR pond significantly by providing the critical information needed about spatial variability in parameters controlling infiltration rates.

  10. MEASUREMENTS OF INFILTRATION RATES IN COMPACTED URBAN SOILS

    EPA Science Inventory

    Previous research hs identified significant reductions in infiltration rates in disturbed urban soils, More than 150 prior tests were conducted in predominately sandy and clayey urban soils in the Birmingham and Mobile, AL areas. Infiltration in Clayey soils ws found to be affect...

  11. Linking denitrification and infiltration rates during managed groundwater recharge.

    PubMed

    Schmidt, Calla M; Fisher, Andrew T; Racz, Andrew J; Lockwood, Brian S; Huertos, Marc Los

    2011-11-15

    We quantify relations between rates of in situ denitrification and saturated infiltration through shallow, sandy soils during managed groundwater recharge. We used thermal methods to determine time series of point-specific flow rates, and chemical and isotopic methods to assess denitrification progress. Zero order denitrification rates between 3 and 300 μmol L(-1) d(-1) were measured during infiltration. Denitrification was not detected at times and locations where the infiltration rate exceeded a threshold of 0.7 ± 0.2 m d(-1). Pore water profiles of oxygen and nitrate concentration indicated a deepening of the redoxocline at high flow rates, which reduced the thickness of the zone favorable for denitrification. Denitrification rates were positively correlated with infiltration rates below the infiltration threshold, suggesting that for a given set of sediment characteristics, there is an optimal infiltration rate for achieving maximum nitrate load reduction and improvements to water supply during managed groundwater recharge. The extent to which results from this study may be extended to other managed and natural hydrologic settings remains to be determined, but the approach taken in this study should be broadly applicable, and provides a quantitative link between shallow hydrologic and biogeochemical processes.

  12. Modeling the abnormally slow infiltration rate in mesoporous films.

    PubMed

    Berli, Claudio L A; Mercuri, Magalí; Bellino, Martín G

    2017-01-18

    Mesoporous films have been shown to exhibit striking behaviors in capillary-driven infiltration experiments. The process has been shown to follow classical Lucas-Washburn dynamics, but the effective pore radius has been calculated from hydrodynamic resistance considerations to be orders of magnitude lower than measured pore dimensions. In addition, the infiltration rate has been observed to decrease with increasing pore diameter, in contrast to the expected trend for capillary-like pores. Here, we present a simple model accounting for the mechanism behind these anomalous effects. We found the infiltration rate to be inversely proportional to the cubed ratio of pore to neck size. This physical scaling correctly modeled both the magnitude of the infiltration rate and its variation with pore diameters, for a wide range of experimental data. The model established a connection between capillary filling dynamics and nanoscale pore structure, which is of practical interest for the design and characterization of mesoporous films.

  13. Reduce Air Infiltration in Furnaces (English/Chinese) (Fact Sheet)

    SciTech Connect

    Not Available

    2011-10-01

    Chinese translation of the Reduce Air Infiltration in Furnaces fact sheet. Provides suggestions on how to improve furnace energy efficiency. Fuel-fired furnaces discharge combustion products through a stack or a chimney. Hot furnace gases are less dense and more buoyant than ambient air, so they rise, creating a differential pressure between the top and the bottom of the furnace. This differential, known as thermal head, is the source of a natural draft or negative pressure in furnaces and boilers. A well-designed furnace (or boiler) is built to avoid air leakage into the furnace or leakage of flue gases from the furnace to the ambient. However, with time, most furnaces develop cracks or openings around doors, joints, and hearth seals. These openings (leaks) usually appear small compared with the overall dimensions of the furnace, so they are often ignored. The negative pressure created by the natural draft (or use of an induced-draft fan) in a furnace draws cold air through the openings (leaks) and into the furnace. The cold air becomes heated to the furnace exhaust gas temperature and then exits through the flue system, wasting valuable fuel. It might also cause excessive oxidation of metals or other materials in the furnaces. The heat loss due to cold air leakage resulting from the natural draft can be estimated if you know four major parameters: (1) The furnace or flue gas temperature; (2) The vertical distance H between the opening (leak) and the point where the exhaust gases leave the furnace and its flue system (if the leak is along a vertical surface, H will be an average value); (3) The area of the leak, in square inches; and (4) The amount of operating time the furnace spends at negative pressure. Secondary parameters that affect the amount of air leakage include these: (1) The furnace firing rate; (2) The flue gas velocity through the stack or the stack cross-section area; (3) The burner operating conditions (e.g., excess air, combustion air temperature

  14. Modelling of percolation rate of stormwater from underground infiltration systems.

    PubMed

    Burszta-Adamiak, Ewa; Lomotowski, Janusz

    2013-01-01

    Underground or surface stormwater storage tank systems that enable the infiltration of water into the ground are basic elements used in Sustainable Urban Drainage Systems (SUDS). So far, the design methods for such facilities have not taken into account the phenomenon of ground clogging during stormwater infiltration. Top layer sealing of the filter bed influences the infiltration rate of water into the ground. This study presents an original mathematical model describing changes in the infiltration rate variability in the phases of filling and emptying the storage and infiltration tank systems, which enables the determination of the degree of top ground layer clogging. The input data for modelling were obtained from studies conducted on experimental sites on objects constructed on a semi-technological scale. The experiment conducted has proven that the application of the model developed for the phase of water infiltration enables us to estimate the degree of module clogging. However, this method is more suitable for reservoirs embedded in more permeable soils than for those located in cohesive soils.

  15. Weed management using goats: Effects on water infiltration rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Goats are used increasingly for weed control, fire fuel reduction and ecological restoration. The high stocking rates typical of these applications have been reported to decrease the rate of water infiltration in goat pastures. The hypothesis that annual goat browsing for weed control decreases infi...

  16. An investigation of infiltration and indoor air quality

    SciTech Connect

    Not Available

    1990-09-01

    A multitask study was performed in the State of New York to provide information for guiding home energy conservation programs while maintaining acceptable indoor air quality. During this study, the statistical distribution of radon concentrations inside 2400 homes was determined. The relationships among radon levels, house characteristics, and sources were also investigated. The direct impact that two specific air infiltration reduction measures -- caulking and weatherstripping of windows and doors, and installation of storm windows and storm doors -- have on house air leakage was investigated in 60 homes. The effect of house age on the impact of weatherization was also evaluated. Indoor and outdoor measurements of NO{sub 2}, CO, SO{sub 2}, and respirable suspended particulates (RSP) were made for 400 homes to determine the effect of combustion sources on indoor air quality and to characterize the statistical distribution of the concentrations. Finally, the combustion source data were combined with the information on air infiltration reduction measures to estimate the potential impact of these measures on indoor air quality. 87 tabs.

  17. Vadose Zone Infiltration Rates from Sr isotope Measurements

    NASA Astrophysics Data System (ADS)

    Maher, K.; Maher, K.; DePaolo, D. J.; DePaolo, D. J.; Conrad, M.

    2001-12-01

    Predicting infiltration rates and recharge through the vadose zone in arid regions is difficult and hence developing methods for the measurement of infiltration rates is important. We have been investigating the use of Sr isotope measurements for determining infiltration at the 200 Area plateau on the Hanford reservation in central Washington. In this context, infiltration affects the transport of contaminants to the water table as well as recharge of the groundwater system. Using Sr isotopes for this purpose requires drill core and water samples from the vadose zone, although leaches of the cores can substitute for water samples. Complementary information, including some constraints on regional recharge, can also be obtained using water samples from groundwater monitoring wells. The VZ method is based on the fact that the Sr isotope ratio of soil water just below the surface is often set by dissolution of aeolian material including carbonate, and this ratio is different from the average value in the deeper underlying vadose zone rock matrix. As water infiltrates, the Sr isotopic composition of the water changes toward the rock values as a result of Sr released from the rocks by weathering reactions. The rate of change with depth of the Sr isotope ratio of the vadose zone water is a function ultimately of q/R; the ratio of the infiltration flux (q) to the bulk rock weathering rate (R). Where it is possible to evaluate R, q can be estimated. As data accumulate it may be possible to improve the calibration of the method. At Hanford the vadose zone rock material is mostly unconsolidated sand, silt, and gravel of broadly granitic composition, which constitute the Hanford and Ringold formations. Annual precipitation is about 160 mm/yr. Drilling and coring of a ca. 70m hole to the water table in 1999 as part of the Hanford groundwater monitoring program, in a relatively undisturbed area of the site, allowed us to generate a unique Sr isotope data set. The Sr isotope

  18. Integrated loading rate determination for wastewater infiltration system sizing

    SciTech Connect

    Jenssen, P.D. . Centre for Soil and Environmental Research); Siegrist, R.L. )

    1991-01-01

    One of the principal parameters used in wastewater system design is the hydraulic loading rate. Historically the determination of the loading rate has been a straight forward process involving selection of a rate based on soil texture or water percolation rate. Research and experience over the past decade has provided additional insight into the complex processes occurring within wastewater-amended soil systems and has suggested the fallacy of this approach. A mean grain size vs. sorting (MESO) diagram constitutes a new basis for soil classification for wastewater infiltration system design. Crude characterization of the soil hydraulic properties is possible according to the MESO Diagram and loading rate as well as certain purification aspects can be assessed from the diagram. In this paper, an approach is described based on the MESO Diagram that integrates soil properties and wastewater pretreatment to yield a loading rate. 53 refs., 3 figs., 2 tabs.

  19. Spatiotemporally‐Resolved Air Exchange Rate as a Modifier of Acute Air Pollution‐Related Morbidity in AtlantaMorbidity in Atlanta

    EPA Science Inventory

    Epidemiological studies frequently use central site concentrations as surrogates of exposure to air pollutants. Variability in air pollutant infiltration due to differential air exchange rates (AERs) is potentially a major factor affecting the relationship between central site c...

  20. Comparison of soil infiltration rates in burned and unburned mountainous watersheds

    USGS Publications Warehouse

    Martin, D.A.; Moody, J.A.

    2001-01-01

    Steady-state infiltration measurements were made at mountainous sites in New Mexico and Colorado, USA, with volcanic and granitic soils after wildfires and at comparable unburned sites. We measured infiltration in the New Mexico volcanic soils under two vegetation types, ponderosa pine and mixed conifer, and in the Colorado granitic soils under ponderosa pine vegetation. These measurements were made within high-severity burn areas using a portable infiltrometer with a 0.017 m2 infiltration area and artificial rainfall rates ranging from 97 to 440 mm h-1. Steady-state infiltration rates were less at all burned sites relative to unburned sites. The volcanic soil with ponderosa pine vegetation showed the greatest difference in infiltration rates with a ratio of steady-state infiltration rate in burned sites to unburned soils equal to 0.15. Volcanic soils with mixed conifer vegetation had a ratio (burned to unburned soils) of at most 0.38, and granitic soils with ponderosa pine vegetation had a ratio of 0.38. Steady-state infiltration rates on unburned volcanic and granitic soils with ponderosa pine vegetation are not statistically different. We present data on the particle-size distribution at all the study sites and examples of wetting patterns produced during the infiltration experiments. Published in 2001 by John Wiley and Sons, Ltd.

  1. AIR INFILTRATION MEASUREMENTS USING TRACER GASES: A LITERATURE REVIEW

    EPA Science Inventory

    The report gives results of a literature review of air filtration measurements using tracer gases, including sulfur hexafluoride, hydrogen, carbon monoxide, carbon dioxide, nitrous oxide, and radioactive argon and krypton. Sulfur hexafluoride is the commonest tracer gas of choice...

  2. Virus removal during groundwater recharge: effects of infiltration rate on adsorption of poliovirus to soil

    SciTech Connect

    Vaughn, J.M.; Landry, E.F.; Beckwith, C.A.; Thomas, M.Z.

    1981-01-01

    Studies were conducted to determine the influence of infiltration rate on poliovirus removal during groundwater recharge with tertiary-treated wastewater effluents. Experiments were conducted at a uniquely designed, field-situated test recharge basin facility through which some 62,000 m/sup 3/ of sewage had been previously applied. Recharge at high infiltration rates (75 to 100 cm/h) resulted in the movement of considerable numbers of seeded poliovirus to the groundwater. Moderately reduced infiltration rates (6 cm/h) affected significantly improved virus removal. Very low infiltration rates (0.5 to 1.0 cm/h), achieved by partial clogging of the test basin, yielded the greatest virus removal efficiencies.

  3. Statistical methods to study soil infiltration rate in Kharga Oasis, Egypt.

    NASA Astrophysics Data System (ADS)

    Gamie, Rasha; De Smedt, Florimond

    2016-04-01

    Agricultural expansion in the Kahrga oasis, located in the western desert of Egypt, strongly depends on irrigation. Hence, the infiltration rate is a key parameter for further development. The infiltration rate was measured in the field using a double ring infiltrometer at 20 m intervals in a 120 m by 120 m plot, together with 12 other relevant physical and chemical soil parameters. The resulting data were statistically analyzed using principal component and linear regression analyses. Results show that the infiltration rate is highly variable in the study area, and strongly positively correlated with hydraulic conductivity and negatively with silt, clay and carbonates contents of the soil. Principle component analysis showed that most of the variation in the data is assigned in the first 3 principle components. The first component explains 36% of the total variation and is strongly linked with soil structure; the second component explains 18% of the total variation and is linked to soil texture; the third component explains 13% and is linked to chemical properties but has no link with infiltration rate; all other components just represent noise in the data and must be attributed to measurement errors, randomness and soil heterogeneity. Multiple linear regression analysis shows that the only relevant factors to predict infiltration rate are hydraulic conductivity, and silt and carbonate content of the soil. The regression equation is only able to predict about half of the variation of the infiltrations rate, while the other half remains unexplained.

  4. Relationship between soil erodibility and modeled infiltration rate in different soils

    NASA Astrophysics Data System (ADS)

    Wang, Guoqiang; Fang, Qingqing; Wu, Binbin; Yang, Huicai; Xu, Zongxue

    2015-09-01

    The relationship between soil erodibility, which is hard to measure, and modeled infiltration rate were rarely researched. Here, the soil erodibility factors (K and Ke in the USLE, Ki and K1 in the WEPP) were calculated and the infiltration rates were modeled based on the designed laboratory simulation experiments and proposed infiltration model, in order to build their relationship. The impacts of compost amendment on the soil erosion characteristics and relationship were also studied. Two contrasting agricultural soils (bare and cultivated fluvo-aquic soils) were used, and different poultry compost contents (control, low and high) were applied to both soils. The results indicated that the runoff rate, sediment yield rate and soil erodibility of the bare soil treatments were generally higher than those of the corresponding cultivated soil treatments. The application of composts generally decreased sediment yield and soil erodibility but did not always decrease runoff. The comparison of measured and modeled infiltration rates indicated that the model represented the infiltration processes well with an N-S coefficient of 0.84 for overall treatments. Significant negative logarithmic correlations have been found between final infiltration rate (FIR) and the four soil erodibility factors, and the relationship between USLE-K and FIR demonstrated the best correlation. The application of poultry composts would not influence the logarithmic relationship between FIR and soil erodibility. Our study provided a useful tool to estimate soil erodibility.

  5. Seasonal changes of the infiltration rates in urban parks of Valencia City, Eastern Spain

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Keesstra, Saskia; Burguet, María; Pereira, Paulo; Esteban Lucas-Borja, Manuel; Martinez-Murillo, Juan F.

    2016-04-01

    Infiltration is a key process of the hydrological cycle. Infiltration also controls the soil water resources, and the development of the vegetation, and moreover, in the Mediterranean, determines the runoff generation (Cerdà, 1996; 1997; 2001). In the Mediterranean, the infiltration in forest soils shows high spatial variability and seasonal and temporal changes (Cerdà, 1999; Bodí and Cerdà, 2009) and is being affected by forest fires (Cerdà, 1998), which introduce a new temporal change in the seasonality of the infiltration rates. Although the forest soils are well assessed, there is no information about the infiltration in urban areas in Mediterranean cities. The Mediterranean dense urban systems use to be treated as impermeable areas. However, the cities show areas covered by vegetation and with soils that allow the rainfall to infiltrate. Those areas are mainly the parks. In order to shed some light on the infiltration capacity of the soils of the urban area of Valencia city 30 rainfall simulations experiments (Cerdà, 1996) and 90 ring infiltrometer (10 cm diameter) measurements were carried out in January 2011, and they were repeated in July 2011, to compare wet (19.4 % of soil moisture) and dry (5.98 % of soil moisture) soils. The infiltration curves where fitted to the Horton (1933) equation and they lasted for 1 hour. The results show that the infiltration is 11 times higher when measured with ring infiltrometer than with the simulated rainfall at 55 mmh-1, and that the infiltration rates where higher in summer than in winter: 2.01 higher for the ring infiltrometer, and 1.45 higher when measured with the rainfall simulator. In comparison to the soils from the forest areas, the infiltration rate in the gardens were lower, with values of 10.23 and 21.65 mm h-1 in average for winter and summer when measured with the rainfall simulator. Similar results were found with the ring infiltrometer. It was also found a clear relationship between the vegetation

  6. Probabilistic estimation of residential air exchange rates for population-based human exposure modeling

    EPA Science Inventory

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER meas...

  7. The effect of surface cover on infiltration rate in steep forest plantations

    NASA Astrophysics Data System (ADS)

    Hiraoka, M.; Onda, Y.; Kato, H.; Ito, S.; Mizugaki, S.

    2007-12-01

    The Japanese cypress (Hinoki; Chamaecyparis obtusa) is a major commercial tree species in Japan, and without thinning of high-density stands, canopy closure prevents development of understory vegetation. Therefore there is a concern for overlandflow and sediment yield due to infiltration rate lowering from steep hillslopes of Japanese cypress plantation. We developed a light-weight rainfall simulator based on the design of Meyer and Harmon (1979). A flat fan Veejet 80150 spraying nozzle (Spraying systems Co., USA) is mounted on the manifold at 2.13 m high from the plot surface. The nozzle oscillates so that the spray fans swept across the targeting 1m x 1m plot. The Veejet 80150 spraying nozzle produces large raindrops larger than 2 mm in diameter, and can simulate the high raindrop kinetic energy of natural storm. A targeted rainfall rate is 180 mm/h. Total 25 sprinkling experiments have been conducted on 35-degree hillslopes with varying surface cover. We obtained the minimum infiltration rate of 14 mm/h where the surface cover is very little. The infiltration rates were plotted against the total understory vegetation and dry weight of total surface cover including litter. The infiltration rate increased with the increasing total surface cover, and higher regression coefficient is obtained for the case of the total surface cover. These results will contribute to the future modeling studies of overlandflow occurrences for the catchment scales.

  8. The effect of surface cover and soil devastation on infiltration rate in steep forest plantations

    NASA Astrophysics Data System (ADS)

    Onda, Y.; Hiraoka, M.; Kato, H.; Gomi, T.; Miyata, S.; Mizugaki, S.

    2008-12-01

    The Japanese cypress (Hinoki; Chamaecyparis obtusa) is a major commercial tree species in Japan, and without thinning of high-density stands, canopy closure prevents development of understory vegetation. Therefore there is a concern for overlandflow and sediment yield due to infiltration rate lowering. We developed a light-weight rainfall simulator based on the design of Meyer and Harmon (1979). A flat fan Veejet 80150 spraying nozzle (Spraying systems Co., USA) is mounted on the manifold at 2.13 m high from the plot surface. The nozzle oscillates so that the spray fan sweeps across the targeting 1 m x 1 m plot. The Veejet 80150 spraying nozzle produces large raindrops larger than 2 mm in diameter, and can simulate the high raindrop kinetic energy of natural throughfall. A targeted rainfall rate is 180 mm/h. About 30 sprinkling experiments have been conducted on 35-degree hillslopes with varying surface cover in 5 locations in Japan. We obtained the minimum infiltration rate of 14 mm/h where the surface cover is very little. The infiltration rates were plotted against the total understory vegetation and dry weight of total surface cover including litter. The infiltration rate increased with the increasing total surface cover, and generally higher regression coefficient was found for the case of the total surface cover. In some cases, high infiltration rates were obtained where surface cover is low. Two possible explanations can be made; 1) surface soil (especially fine particles) has been washed away, where soil is mostly composed of gravel and the percentage of fine fraction is low, or 2) because of long-term soil loss by raindrop detachment, remaining soil looks like "ghanging"h between exposed fine root networks of Japanese cypress, where soil bulk density is significantly lower than other site. Therefore the infiltration rate in the devastated Japanese cypress plantations is not only controlled by loss of surface vegetation by low light condition, but soil

  9. Infiltration and interrill erosion rates after a wildfire in western Montana, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 2000 Valley Complex wildfire burned in steep montane forests with ash cap soils in western Montana, USA. The effects of high burn severity on forest soil hydrologic function was examined using rainfall simulations (100 mm h-1 for 1 h) on 0.5-m2 plots. Infiltration rates and sediment yields and c...

  10. Air Leakage Rates in Typical Air Barrier Assemblies

    SciTech Connect

    Hun, Diana E.; Atchley, Jerald Allen; Childs, Phillip W.

    2016-11-01

    Estimates for 2010 indicate that infiltration in residential buildings was responsible for 2.85 quads of energy (DOE 2014), which is about 3% of the total energy consumed in the US. One of the mechanisms being implemented to reduce this energy penalty is the use of air barriers as part of the building envelope. These technologies decrease airflow through major leakage sites such as oriented strand board (OSB) joints, and gaps around penetrations (e.g., windows, doors, pipes, electrical outlets) as indicated by Hun et al. (2014). However, most air barrier materials do not properly address leakage spots such as wall-to-roof joints and wall-to-foundation joints because these are difficult to seal, and because air barrier manufacturers usually do not provide adequate instructions for these locations. The present study focuses on characterizing typical air leakage sites in wall assemblies with air barrier materials.

  11. Estimating infiltration rates for intermittent streams in the semiarid southwest: implications for ecosystem processes

    NASA Astrophysics Data System (ADS)

    Nicholas, H. D.; Meixner, T.; Lohse, K. A.

    2011-12-01

    Directional climate change may lead to increased aridity and fewer precipitation events across the American southwest. Determining infiltration fluxes during monsoonal rainstorms may be the key to predicting how changing precipitation frequency will affect groundwater percolation and potential recharge. Our study focuses on the following research question: How much water infiltrates- and at what rates- during flow events in ephemeral streams? An additional topic we hope to address as the project processes progresses is the link between intermittent flow variably and its affecteffect on water availability as it applies to ecosystem processes, from vegetation growth and diversity to insect populations, etc. As water is the limiting factor for ecosystem health and dynamics in the semi-arid southwest, the value of measuring and modeling variably saturated porous media is incredibly high. In order to address these topics, twelve intermittent stream sections in southern Arizona have been chosen for infiltration flux analysis. These twelve locations have been instrumented with vertical profiles of iButton temperature sensors in the streambed subsurface along several transects per reach. The iButton sensors log temperature hourly at depths of 0, 10, and 30cm, or in some locations at depths of 10, 30, and 50cm where possible. Deployed in protective metal housings directly in the sediment, they represent more dynamic possibilities for accurate infiltration measurements compared to their predecessors which were deployed in PVC pipe in sediment. The vertical profile temperature recordings may be analyzed by observing the propagation of amplitude and phase shifts that occur in the presence of water as you move deeper into the soil profile. Using temperature as a proxy for water infiltration rates makes flux estimations more reasonable in these highly unpredictable variably saturated zones. Temperature data is paired with modified TidbiT data-loggers which record electrical

  12. Microflowmeter-tension disc infiltrometer: Part II - Hydraulic properties estimation from transient infiltration rate analysis

    NASA Astrophysics Data System (ADS)

    Moret-Fernández, David; Latorre, Borja; González-Cebollada, César

    2012-10-01

    SummaryMeasurements of soil sorptivity (S0) and hydraulic conductivity (K0) are of paramount importance for many soil-related studies involving disciplines such as agriculture, forestry and hydrology. In the last two decades, the disc infiltrometer has become a very popular instrument for estimations of soil hydraulic properties. The previous paper in this series presented a new design of disc infiltrometer that directly estimates the transient flow of infiltration rate curves. The objective of this paper is to present a simple procedure for estimating K0 and S0 from the linearisation of the transient infiltration rate curve with respect to the inverse of the square root of time (IRC). The technique was tested in the laboratory on 1D sand columns and 1D and 3D 2-mm sieved loam soil columns and validated under field conditions on three different soil surfaces. The estimated K0 and S0 were subsequently compared to the corresponding values calculated with the Vandervaere et al. (2000) technique, which calculates the soil hydraulic parameters from the linearisation of the differential cumulative infiltration curve with respect to the square root of time (DCI). The results showed that the IRC method, with more significant linearised models and higher values of the coefficient of determination, allows more accurate estimation of K0 and S0 than the DCI technique. Field experiments demonstrate that the IRC procedure also makes it possible to detect and eliminate the effect of the sand contact layer commonly used in the disc infiltrometry technique. Comparison between the measured and the modelled cumulative infiltration curves for the K0 and S0 values estimated by the DCI and IRC methods in all the 1D and 3D laboratory experiments and field measurements shows that the IRC technique allowed better fittings between measured and modelled cumulative infiltration curves, which indicates better estimations of the soil hydraulic properties.

  13. A Study on Dispersion and Rate of Fat Infiltration in the Lumbar Spine of Patients with Herniated Nucleus Polpusus

    PubMed Central

    Kong, Bong-jun; Lim, Jong-soo; Kim, Kyung

    2014-01-01

    [Purpose] This study investigated the relationship between herniated nucleus pulposus (HNP) and fat infiltration of muscles around the spine by measuring body mass index (BMI) and fat infiltration of the muscles around the spine. [Subjects and Methods] Subjects were 82 people, both men and women they were divided into two groups, a normal group and a patient group who were suffering from serious HNP between L4 and L5. Of the anthropometric measurement, and fat infiltration muscles by measuring the cross-sectional area from the center of the disc to the muscle around the spine and the cross-sectional area of fat infiltration. [Results] Fat infiltration rate of each lumbar layer in the normal group was different L34–L45 and L45–L5S1, but not between L23–L34. Fat infiltration in the muscle between the normal group and patients with HNP was different in the layers and the difference was greatest in the L5–S1 layer. [Conclusion] We performed correlation analysis of BMI and the total fat infiltration rate in each group to find the relationship between obesity and fat infiltration in the lumbar spine. Fat infiltration increased, and normal people or patients with chronic back pain are considered to be exposed to other diseases as fat infiltration in the lumbar spine increases. PMID:24567672

  14. Pre- and Post-Fire Infiltration Rates in a Montane Mixed Conifer Ecosystem

    NASA Astrophysics Data System (ADS)

    Kopp, E. S.; Pohlmann, M. A.; Jones, C. A.; Chorover, J.; Schaap, M. G.

    2013-12-01

    The NSF-funded Catalina-Jemez Critical Zone Observatory (CZO) studies couplings among hydrologic, lithologic, ecological, and geochemical dynamics in the Southwest U.S. The motivation to study this region is to understand and to develop predictive models of how slow changes and abrupt disturbances affect landscape evolution and water resources for growing urban populations. One of the prevalent disturbances in Southwestern forested ecosystems is fire, which can dramatically alter near surface hydraulic properties and cause large changes in hydrological response in catchments. This poster will present a unique data set of pre- and post-fire infiltration and subsurface data collected before and shortly after the June 2013 Thompson Ridge Fire near Redondo Peak in the Valles Caldera 10 miles north of Jemez Springs, NM. Single ring pre-fire infiltration measurements were taken in July 2011 at 22 different locations with high-precision GPS tags. Similar post-fire infiltration measurements were taken within 1 meter of spatial accuracy of the pre-fire measurements in July 2013. The near-surface soil was analyzed for texture and organic matter content at 53 GPS-referenced locations in 2011, and a more detailed soil analysis is currently being analyzed in the laboratory for the 22 infiltration sites (5 depth increments down to about 50 cm). Because of the recent nature of the burn and subsequent sampling, complete results from data analysis are not yet available, however, the poster will provide a statistical analysis among pre- and post fire infiltration rates, established burn intensity classes, and subsurface changes such as soil texture and organic matter content.

  15. Probabilistic estimation of residential air exchange rates for ...

    EPA Pesticide Factsheets

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER measurements. An algorithm for probabilistically estimating AER was developed based on the Lawrence Berkley National Laboratory Infiltration model utilizing housing characteristics and meteorological data with adjustment for window opening behavior. The algorithm was evaluated by comparing modeled and measured AERs in four US cities (Los Angeles, CA; Detroit, MI; Elizabeth, NJ; and Houston, TX) inputting study-specific data. The impact on the modeled AER of using publically available housing data representative of the region for each city was also assessed. Finally, modeled AER based on region-specific inputs was compared with those estimated using literature-based distributions. While modeled AERs were similar in magnitude to the measured AER they were consistently lower for all cities except Houston. AERs estimated using region-specific inputs were lower than those using study-specific inputs due to differences in window opening probabilities. The algorithm produced more spatially and temporally variable AERs compared with literature-based distributions reflecting within- and between-city differences, helping reduce error in estimates of air pollutant exposure. Published in the Journal of

  16. High Dose-Rate Intracavitary Brachytherapy for Cervical Carcinomas With Lower Vaginal Infiltration

    SciTech Connect

    Kazumoto, Tomoko Kato, Shingo; Tabushi, Katsuyoshi; Kutsutani-Nakamura, Yuzuru; Mizuno, Hideyuki; Takahashi, Michiko; Shiromizu, Kenji; Saito, Yoshihiro

    2007-11-15

    Purpose: This report presents the clinical applications of an automated treatment-planning program of high-dose-rate intracavitary brachytherapy (HDR-ICBT) for advanced uterine cervical cancer infiltrating the parametrium and the lower vagina. Methods and Materials: We adopted HDR-ICBT under optimized dose distribution for 22 cervical cancer patients with tumor infiltration of the lower half of the vagina. All patients had squamous cell carcinoma with International Federation of Gynecology and Obstetrics clinical stages IIB-IVA. After whole pelvic external beam irradiation with a median dose of 30.6 Gy, a conventional ICBT was applied as 'pear-shaped' isodose curve. Then 3-4 more sessions per week of this new method of ICBT were performed. With a simple determination of the treatment volume, the cervix-parametrium, and the lower vagina were covered automatically and simultaneously by this program, that was designated as 'utero-vaginal brachytherapy'. The mean follow-up period was 87.4 months (range, 51.8-147.9 months). Results: Isodose curve for this program was 'galaxy-shaped'. Five-year local-progression-free survival and overall survival rates were 90.7% and 81.8%, respectively. Among those patients with late complications higher than Grade 2 Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer morbidity score, only one (4.5%) developed severe proctitis. Conclusions: Because of the favorable treatment outcomes, this treatment-planning program with a simplified target-volume based dosimetry was proposed for cervical cancer with lower vaginal infiltration.

  17. Infiltration of forest fire and residential wood smoke: an evaluation of air cleaner effectiveness.

    PubMed

    Barn, Prabjit; Larson, Timothy; Noullett, Melanie; Kennedy, Susan; Copes, Ray; Brauer, Michael

    2008-09-01

    Communities impacted by fine-particle air pollution (particles with an aerodynamic diameter less than 2.5 microm; PM(2.5)) from forest fires and residential wood burning require effective, evidence-based exposure-reduction strategies. Public health recommendations during smoke episodes typically include advising community members to remain indoors and the use of air cleaners, yet little information is available on the effectiveness of these measures. Our study attempted to address the following objectives: to measure indoor infiltration factor (F(inf)) of PM(2.5) from forest fires/wood smoke, to determine the effectiveness of high-efficiency particulate air (HEPA) filter air cleaners in reducing indoor PM(2.5), and to analyze the home determinants of F(inf) and air cleaner effectiveness (ACE). We collected indoor/outdoor 1-min PM(2.5) averages and 48-h outdoor PM(2.5) filter samples for 21 winter and 17 summer homes impacted by wood burning and forest fire smoke, respectively, during 2004-2005. A portable HEPA filter air cleaner was operated indoors with the filter removed for one of two sampling days. Particle F(inf) and ACE were calculated for each home using a recursive model. We found mean F(inf)+/-SD was 0.27+/-0.18 and 0.61+/-0.27 in winter (n=19) and summer (n=13), respectively, for days when HEPA filters were not used. Lower F(inf)+/-SD values of 0.10+/-0.08 and 0.19+/-0.20 were found on corresponding days when HEPA filters were in place. Mean+/-SD ACE ([F(inf) without filter-F(inf) with filter]/F(inf) without filter) in winter and summer were 55+/-38% and 65+/-35%, respectively. Number of windows and season predicted F(inf) (P<0.001). No significant predictors of ACE were identified. Our findings show that remaining indoors combined with use of air cleaner can effectively reduce PM(2.5) exposure during forest fires and residential wood burning.

  18. Effect of irrigation with treated wastewater on soil chemical properties and infiltration rate.

    PubMed

    Bedbabis, Saida; Ben Rouina, Béchir; Boukhris, Makki; Ferrara, Giuseppe

    2014-01-15

    In Tunisia, water scarcity is one of the major constraints for agricultural activities. The reuse of treated wastewater (TWW) in agriculture can be a sustainable solution to face water scarcity. The research was conducted for a period of four years in an olive orchard planted on a sandy soil and subjected to irrigation treatments: a) rain-fed conditions (RF), as control b) well water (WW) and c) treated wastewater (TWW). In WW and TWW treatments, an annual amount of 5000 m(3) ha(-1) of water was supplied to the orchard. Soil samples were collected at the beginning of the study and after four years for each treatment. The main soil properties such as electrical conductivity (EC), pH, soluble cations, chloride (Cl(-)), sodium adsorption ratio (SAR), organic matter (OM) as well as the infiltration rate were investigated. After four years, either a significant decrease of pH and infiltration rate or a significant increase of OM, SAR and EC were observed in the soil subjected to treated wastewater treatment.

  19. Determination of infiltration and percolation rates along a reach of the Santa Fe River near La Bajada, New Mexico

    USGS Publications Warehouse

    Thomas, Carole L.; Stewart, Amy E.; Constantz, Jim E.

    2000-01-01

    Two methods, one a surface-water method and the second a ground-water method, were used to determine infiltration and percolation rates along a 2.5-kilometer reach of the Santa Fe River near La Bajada, New Mexico. The surface-water method uses streamflow measurements and their differences along a stream reach, streamflow-loss rates, stream surface area, and evaporation rates to determine infiltration rates. The ground-water method uses heat as a tracer to monitor percolation through shallow streambed sediments. Data collection began in October 1996 and continued through December 1997. During that period the stream reach was instrumented with three streamflow gages, and temperature profiles were monitored from the stream-sediment interface to about 3 meters below the streambed at four sites along the reach. Infiltration is the downward flow of water through the stream- sediment interface. Infiltration rates ranged from 92 to 267 millimeters per day for an intense measurement period during June 26- 28, 1997, and from 69 to 256 millimeters per day during September 27-October 6, 1997. Investigators calculated infiltration rates from streamflow loss, stream surface-area measurements, and evaporation-rate estimates. Infiltration rates may be affected by unmeasured irrigation-return flow in the study reach. Although the amount of irrigation-return flow was none to very small, it may result in underestimation of infiltration rates. The infiltration portion of streamflow loss was much greater than the evaporation portion. Infiltration accounted for about 92 to 98 percent of streamflow loss. Evaporation-rate estimates ranged from 3.4 to 7.6 millimeters per day based on pan-evaporation data collected at Cochiti Dam, New Mexico, and accounted for about 2 to 8 percent of streamflow loss. Percolation is the movement of water through saturated or unsaturated sediments below the stream-sediment interface. Percolation rates ranged from 40 to 109 millimeters per day during June 26

  20. Infiltration as Ventilation: Weather-Induced Dilution

    SciTech Connect

    Sherman, Max H.; Turner, William J.N.; Walker, Iain S.

    2011-06-01

    The purpose of outdoor air ventilation is to dilute or remove indoor contaminants to which occupants are exposed. It can be provided by mechanical or natural means. In most homes, especially older homes, weather-driven infiltration provides the dominant fraction of the total ventilation. As we seek to provide good indoor air quality at minimum energy cost, it is important to neither over-ventilate nor under-ventilate. Thus, it becomes critically important to evaluate correctly the contribution infiltration makes to the total outdoor air ventilation rate. Because weather-driven infiltration is dependent on building air leakage and weather-induced pressure differences, a given amount of air leakage will provide different amounts of infiltration. Varying rates of infiltration will provide different levels of contaminant dilution and hence effective ventilation. This paper derives these interactions and then calculates the impact of weather-driven infiltration for different climates. A new “N-factor” is introduced to provide a convenient method for calculating the ventilation contribution of infiltration for over 1,000 locations across North America. The results of this work could be used in indoor air quality standards (specifically ASHRAE 62.2) to account for the contribution of weather-driven infiltration towards the dilution of indoor pollutants.

  1. Evaluation of the particle infiltration efficiency of three passive samplers and the PS-1 active air sampler

    NASA Astrophysics Data System (ADS)

    Markovic, Milos Z.; Prokop, Sebastian; Staebler, Ralf M.; Liggio, John; Harner, Tom

    2015-07-01

    The particle infiltration efficiencies (PIE) of three passive and one active air samplers were evaluated under field conditions. A wide-range particle spectrometer operating in the 250-4140 nm range was used to acquire highly temporally resolved particle-number and size distributions for the different samplers compared to ambient air. Overall, three of the four evaluated samplers were able to acquire a representative sample of ambient particles with PIEs of 91.5 ± 13.7% for the GAPS Network sampler, 103 ± 15.5% for the Lancaster University sampler, and 89.6 ± 13.4% for a conventional PS-1 high-volume active air sampler (Hi-Vol). Significantly (p = 0.05) lower PIE of 54 ± 8.0% was acquired for the passive sampler used under the MONET program. These findings inform the comparability and use of passive and active samplers for measuring particle-associated priority chemicals in air.

  2. Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model (ISES Presentation)

    EPA Science Inventory

    Previous exposure assessment panel studies have observed considerable seasonal, between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure ...

  3. Application of Modular Modeling System to Predict Evaporation, Infiltration, Air Temperature, and Soil Moisture

    NASA Technical Reports Server (NTRS)

    Boggs, Johnny; Birgan, Latricia J.; Tsegaye, Teferi; Coleman, Tommy; Soman, Vishwas

    1997-01-01

    Models are used for numerous application including hydrology. The Modular Modeling System (MMS) is one of the few that can simulate a hydrology process. MMS was tested and used to compare infiltration, soil moisture, daily temperature, and potential and actual evaporation for the Elinsboro sandy loam soil and the Mattapex silty loam soil in the Microwave Radiometer Experiment of Soil Moisture Sensing at Beltsville Agriculture Research Test Site in Maryland. An input file for each location was created to nut the model. Graphs were plotted, and it was observed that the model gave a good representation for evaporation for both plots. In comparing the two plots, it was noted that infiltration and soil moisture tend to peak around the same time, temperature peaks in July and August and the peak evaporation was observed on September 15 and July 4 for the Elinsboro Mattapex plot respectively. MMS can be used successfully to predict hydrological processes as long as the proper input parameters are available.

  4. Estimated Infiltration, Percolation, and Recharge Rates at the Rillito Creek Focused Recharge Investigation Site, Pima County, Arizona

    USGS Publications Warehouse

    Hoffmann, John P.; Blasch, Kyle W.; Pool, Don R.; Bailey, Matthew A.; Callegary, James B.

    2007-01-01

    A large fraction of ground water stored in the alluvial aquifers in the Southwest is recharged by water that percolates through ephemeral stream-channel deposits. The amount of water currently recharging many of these aquifers is insufficient to meet current and future demands. Improving the understanding of streambed infiltration and the subsequent redistribution of water within the unsaturated zone is fundamental to quantifying and forming an accurate description of streambed recharge. In addition, improved estimates of recharge from ephemeral-stream channels will reduce uncertainties in water-budget components used in current ground-water models. This chapter presents a summary of findings related to a focused recharge investigation along Rillito Creek in Tucson, Arizona. A variety of approaches used to estimate infiltration, percolation, and recharge fluxes are presented that provide a wide range of temporal- and spatial-scale measurements of recharge beneath Rillito Creek. The approaches discussed include analyses of (1) cores and cuttings for hydraulic and textural properties, (2) environmental tracers from the water extracted from the cores and cuttings, (3) seepage measurements made during sustained streamflow, (4) heat as a tracer and numerical simulations of the movement of heat through the streambed sediments, (5) water-content variations, (6) water-level responses to streamflow in piezometers within the stream channel, and (7) gravity changes in response to recharge events. Hydraulic properties of the materials underlying Rillito Creek were used to estimate long-term potential recharge rates. Seepage measurements and analyses of temperature and water content were used to estimate infiltration rates, and environmental tracers were used to estimate percolation rates through the thick unsaturated zone. The presence or lack of tritium in the water was used to determine whether or not water in the unsaturated zone infiltrated within the past 40 years

  5. How do soil texture, plant community composition and earthworms affected the infiltration rate in a grassland plant diversity experiment depending on season?

    NASA Astrophysics Data System (ADS)

    Fischer, Christine; Britta, Merkel; Nico, Eisenhauer; Christiane, Roscher; Sabine, Attinger; Stefan, Scheu; Anke, Hildebrandt

    2013-04-01

    Background and aims: In this study we analyzed the influences of plant community characteristics, soil texture and earthworm presence on infiltration rates on a managed grassland plant diversity experiment assessing the role of biotic and abiotic factors on soil hydrology. Methods: We measured infiltration using a hood infiltrometer in subplots with ambient and reduced earthworm density (earthworm extraction) nested in plots of different plant species richness (1, 4, and 16), plant functional group number and composition (1 to 4; legumes, grasses, small herbs, tall herbs) in early summer (June) and autumn (September, October) 2011. Results: The presence of certain plant functional groups such as grasses and legumes influenced infiltration rates and this effect enhanced during the growing season. Infiltration was significantly higher in plots containing legumes than in plots without, and it was significantly lower in the presence of grasses than in their absence. In early summer, earthworm presence and biomass increased the infiltration rates, independently of plant species richness. In October, plant species richness only affected infiltration rates in reduced earthworm plots. At the end of the growing season earthworm populations were negatively influenced by grasses and positively by legumes. In September, infiltration rates were positive related to the proportion of finer grains. The correlation disappears when removing all plots containing legumes from the sample. For all measurements the infiltration rates decreases from early summer to autumn at the matric potentials at pressure zero and -0.02 m, but not for smaller macropores at matric potentials -0.04 and -0.06m. Conclusions: Considering infiltration rates as ecosystem function, this function will largely depend on the ecosystem composition and season, not on biodiversity per se. Our results indicate that biotic factors are of overriding influence for shaping infiltration rates mainly for larger macropores

  6. Review of Air Exchange Rate Models for Air Pollution Exposure Assessments

    EPA Science Inventory

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings, where people spend their time. The AER, which is rate the exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pol...

  7. Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model

    EPA Science Inventory

    between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure and Dose Simulation (SHEDS) model is a population exposure model that uses a pro...

  8. Modelling spatial distribution of soil steady state infiltration rate in an urban park (Vingis Parkas, Vilnius, Lithuania)

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Cerda, Artemi; Depellegrin, Daniel; Misiune, Ieva; Bogunovic, Igor; Menchov, Oleksandr

    2016-04-01

    infiltration rate was 69 mm h-1, with a minimum of 12.72 mm h-1 and a maximum of 692.31 mm h-1. The spatial variability was extremely high (coefficient of variation of 153.71). Among the methods tested the most accurate was SK (RMSE=0.542) and the least precise TPS (RMSE=0.695). With the exception of the IDW5, all the correlations between observed and estimated values were significant at a p<0.05. All the residuals followed the normal distribution. Steady state infiltration was high in the southern and central part of the plot (where the human impact is high) and low in the northern part of the park, where forests are denser. References Bisantino, T., Bingner, R., Chouaib, W., Gentile, F., Trisorio Liuzzi, G. (2015) Estimation of runoff, peak discharge and sediment load at the event scale in a medium-size mediterranean watershed using the annagnps model Land Degradation and Development, 26, 340-355. Brevik, E. C., Cerdà, A., Mataix-Solera, J., Pereg, L., Quinton, J. N., Six, J., Van Oost, K. (2015) The interdisciplinary nature of SOIL. SOIL, 1, 117-129. Cassinari, C., Manfredi, P., Giupponi, L., Trevisan, M., Piccini, C. (2015). Relationship between hydraulic properties and plant coverage of the closed-landfill soils in Piacenza (Po Valley, Italy). Solid Earth, 6, 929-943. Cerdà, A. (1996) Seasonal variability of infiltration rates under contrasting slope conditions in southeast Spain. Geoderma, 69, 217-232. Cerdà, A., González-Pelayo, O., Giménez-Morera, A., Jordán, A., Pereira, P., Novara, A., Brevik, E.C., Prosdocimi, M., Mahmoodabadi, M., Keesstra, S., García Orenes, F., Ritsema, C. (2015) The use of barley straw residues to avoid high erosion and runoff rates on persimmon plantations in Eastern Spain under low frequency - high magnitude simulated rainfall events. Soil Research (In press) Cerdà, A. (2001) Effects of rock fragment cover on soil infiltration, interrill runoff and erosion. European Journal of Soil Science, 52, 59-68. Cerdà, A. (1997) Seasonal changes

  9. Virus removal within a soil infiltration zone as affected by effluent composition, application rate, and soil type.

    PubMed

    Van Cuyk, Sheila; Siegrist, Robert L

    2007-02-01

    The column studies presented in this paper simulated the infiltrative surface of onsite wastewater systems where effluent is applied and where a biomat may form. Two bacteriophages, MS-2 and PRD-1, were used as surrogates for human pathogenic enteric viruses during two tracer tests. A vacuum manifold was used to simulate the drainage effects of an underlying unsaturated soil profile, allowing for the collection of percolate samples at 4 cm immediately below the infiltrative surface. The impact of effluent applied (septic tank effluent (STE) or a simulated ground water), soil type (medium sand or sandy loam), hydraulic loading rate (5 or 25 cm/day) and method of application (four equivalent daily doses or 24 equivalent micro-doses per day) on the removal of viruses were investigated. These unsaturated mini column experiments demonstrated that the removal of viruses within an infiltrative surface zone (of approximately 4 cm) generally improved over time under the conditions studied. An exception occurred in sand-filled columns dosed with STE where the removal of PRD-1 decreased after a period of effluent application. Statistical analysis conducted on the calculated percent removal demonstrated that the quality of the effluent applied to the infiltrative surface is important for removal of MS-2 and PRD-1. Hydraulic loading rate also proved important in the removal of viruses. At the time of tracer test 2, columns dosed at the higher HLR (25 cm/day) had higher percent removals for both MS-2 and PRD-1. Soil type altered the removal of PRD-1 at the time of the second tracer test, at which time sandy loam had higher removal rates for PRD-1. No significant differences were observed between columns dosed four times daily and those dosed 24 times daily for either bacteriophage at either of the tracer test time points. These data suggest that over a relatively short period of operation the infiltrative surface of soil based wastewater treatment systems can achieve much higher

  10. Air velocity distributions inside tree canopies from a variable-rate air-assisted sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A variable-rate, air assisted, five-port sprayer had been in development to achieve variable discharge rates of both liquid and air. To verify the variable air rate capability by changing the fan inlet diameter of the sprayer, air jet velocities impeded by plant canopies were measured at various loc...

  11. Identifying Housing and Meteorological Conditions Influencing Residential Air Exchange Rates in the DEARS and RIOPA Studies: Development of Distributions for Human Exposure Modeling

    EPA Science Inventory

    Appropriate prediction of residential air exchange rate (AER) is important for estimating human exposures in the residential microenvironment, as AER drives the infiltration of outdoor-generated air pollutants indoors. AER differences among homes may result from a number of fact...

  12. Scenario Studies on Effects of Soil Infiltration Rates, Land Slope, and Furrow Irrigation Characteristics on Furrow Irrigation-Induced Erosion

    PubMed Central

    Dibal, Jibrin M.; Ramalan, A. A.; Mudiare, O. J.; Igbadun, H. E.

    2014-01-01

    Furrow irrigation proceeds under several soil-water-furrow hydraulics interaction dynamics. The soil erosion consequences from such interactions in furrow irrigation in Samaru had remained uncertain. A furrow irrigation-induced erosion (FIIE) model was used to simulate the potential severity of soil erosion in irrigated furrows due to interactive effects of infiltration rates, land slope, and some furrow irrigation characteristics under different scenarios. The furrow irrigation characteristics considered were furrow lengths, widths, and stream sizes. The model itself was developed using the dimensional analysis approach. The scenarios studied were the interactive effects of furrow lengths, furrow widths, and slopes steepness; infiltration rates and furrow lengths; and stream sizes, furrow lengths, and slopes steepness on potential furrow irrigation-induced erosion, respectively. The severity of FIIE was found to relate somewhat linearly with slope and stream size, and inversely with furrow lengths and furrow width. The worst soil erosion (378.05 t/ha/yr) was found as a result of the interactive effects of 0.65 m furrow width, 50 m furrow length, and 0.25% slope steepness; and the least soil erosion (0.013 t/ha/yr) was induced by the combined effects of 0.5 l/s, 200 m furrow length, and 0.05% slope steepness. Evidently considering longer furrows in furrow irrigation designs would be a better alternative of averting excessive FIIE. PMID:27382612

  13. Infiltration into Fractured Bedrock

    SciTech Connect

    Salve, Rohit; Ghezzehei, Teamrat A.; Jones, Robert

    2007-09-01

    One potential consequence of global climate change and rapid changes in land use is an increased risk of flooding. Proper understanding of floodwater infiltration thus becomes a crucial component of our preparedness to meet the environmental challenges of projected climate change. In this paper, we present the results of a long-term infiltration experiment performed on fractured ash flow tuff. Water was released from a 3 x 4 m{sup 2} infiltration plot (divided into 12 square subplots) with a head of {approx}0.04 m, over a period of {approx}800 days. This experiment revealed peculiar infiltration patterns not amenable to current infiltration models, which were originally developed for infiltration into soils over a short duration. In particular, we observed that in part of the infiltration plot, the infiltration rate abruptly increased a few weeks into the infiltration tests. We suggest that these anomalies result from increases in fracture permeability during infiltration, which may be caused by swelling of clay fillings and/or erosion of infill debris. Interaction of the infiltration water with subsurface natural cavities (lithophysal cavities) could also contribute to such anomalies. This paper provides a conceptual model that partly describes the observed infiltration patterns in fractured rock and highlights some of the pitfalls associated with direct extension of soil infiltration models to fractured rock over a long period.

  14. High performance air electrode for solid oxide regenerative fuel cells fabricated by infiltration of nano-catalysts

    NASA Astrophysics Data System (ADS)

    Lee, Sung-il; Kim, Jeonghee; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook; Je, Hae-June; Lee, Hae-Weon; Song, Huesup; Yoon, Kyung Joong

    2014-03-01

    A high performance air electrode fabricated by infiltration of highly active nano-catalysts into a porous scaffold is demonstrated for high-temperature solid oxide regenerative fuel cells (SORFCs). The nitrate precursor solution for Sm0.5Sr0.5CoO3 (SSC) catalyst is impregnated into a porous La0.6Sr0.4Co0.2Fe0.8O3 (LSCF)-gadolinia-doped ceria (GDC) composite backbone, and extremely fine SSC nano-particles are uniformly synthesized by in-situ crystallization at the initial stage of SORFC operation via homogeneous nucleation induced by urea decomposition. The SSC nano-catalysts are in the size range of 40-80 nm and stable against coarsening upon the SORFC operation at 750 °C. The electrochemical performance is significantly improved by incorporation of SSC nano-catalysts in both power generation and hydrogen production modes. Systematic analysis on the impedance spectra reveals that the surface modification of the air electrode with nano-catalysts remarkably accelerates the chemical surface exchange reactions for both O2 reduction and O2- oxidation, which are the major limiting processes for SORFC performance.

  15. Nitrogen Transformations in Wetland Soil Cores Measured by (sup15)N Isotope Pairing and Dilution at Four Infiltration Rates

    PubMed Central

    Stepanauskas, R.; Davidsson, E. T.; Leonardson, L.

    1996-01-01

    The effect of water infiltration rate (IR) on nitrogen cycling in a saturated wetland soil was investigated by applying a (sup15)N isotope dilution and pairing method. Water containing [(sup15)N]nitrate was infiltrated through 10-cm-long cores of sieved and homogenized soil at rates of 72, 168, 267, and 638 mm day(sup-1). Then the frequencies of (sup30)N(inf2), (sup29)N(inf2), (sup15)NO(inf3)(sup-), and (sup15)NH(inf4)(sup+) in the outflow water were measured. This method allowed simultaneous determination of nitrification, coupled and uncoupled denitrification, and nitrate assimilation rates. From 3% (at the highest IR) to 95% (at the lowest IR) of nitrate was removed from the water, mainly by denitrification. The nitrate removal was compensated for by the net release of ammonium and dissolved organic nitrogen. Lower oxygen concentrations in the soil at lower IRs led to a sharper decrease in the nitrification rate than in the ammonification rate, and, consequently, more ammonium leaked from the soil. The decreasing organic-carbon-to-nitrogen ratio (from 12.8 to 5.1) and the increasing light A(inf250)/A(inf365) ratio (from 4.5 to 5.2) indicated an increasing bioavailability of the outflowing dissolved organic matter with increasing IR. The efflux of nitrous oxide was also very sensitive to IR and increased severalfold when a zone of low oxygen concentration was close to the outlet of the soil cores. N(inf2)O then constituted 8% of the total gaseous N lost from the soil. PMID:16535352

  16. Influence of loading rate and modes on infiltration of treated wastewater in soil-based constructed wetland.

    PubMed

    Bisone, Sara; Gautier, Mathieu; Masson, Matthieu; Forquet, Nicolas

    2017-01-01

    Over the last 10 years soil-based constructed wetlands for discharge of treated wastewater (TWW) are commonly presented as a valuable option to provide tertiary treatment. The uncomplete knowledge in soil modifications and a lack of clear design practices laid the foundation of this work. The aim of this study was to determine optimal hydraulic loads and to observe the main critical parameters affecting treating performances and hydraulic loads acceptance. For this purpose, a soil rich in clay and backfill was chosen to perform column infiltration tests with TWW. Two loading rates and two loading modes were compared to study the influence of an intermittent feeding. Inlet and outlet waters were periodically analysed and columns were instrumented with balances, tensiometers, O2 and temperature probes. Soil physico-chemical characteristics were also taken into account to better understand the modification of the soil. One of the main expectations of tertiary treatment is to improve phosphate removal. A particular attention was thus given to phosphorus retention. The interest of an intermittent feeding in presence of a soil with high clay content was showed. This study highlighted that an intermittent feeding could make possible the use of a clay-rich soil for water infiltration.

  17. Infiltration modeling guidelines for commercial building energy analysis

    SciTech Connect

    Gowri, Krishnan; Winiarski, David W.; Jarnagin, Ronald E.

    2009-09-30

    This report presents a methodology for modeling air infiltration in EnergyPlus to account for envelope air barrier characteristics. Based on a review of various infiltration modeling options available in EnergyPlus and sensitivity analysis, the linear wind velocity coefficient based on DOE-2 infiltration model is recommended. The methodology described in this report can be used to calculate the EnergyPlus infiltration input for any given building level infiltration rate specified at known pressure difference. The sensitivity analysis shows that EnergyPlus calculates the wind speed based on zone altitude, and the linear wind velocity coefficient represents the variation in infiltration heat loss consistent with building location and weather data.

  18. Air velocity distributions from a variable-rate air-assisted sprayer for tree applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A capability that implements tree structure to control liquid and air flow rates is the preferential design in the development of variable-rate orchard and nursery sprayers. Air jet velocity distributions from an air assisted, five-port sprayer which was under the development to achieve variable-rat...

  19. A field method for measurement of infiltration

    USGS Publications Warehouse

    Johnson, A.I.

    1963-01-01

    The determination of infiltration--the downward entry of water into a soil (or sediment)--is receiving increasing attention in hydrologic studies because of the need for more quantitative data on all phases of the hydrologic cycle. A measure of infiltration, the infiltration rate, is usually determined in the field by flooding basins or furrows, sprinkling, or measuring water entry from cylinders (infiltrometer rings). Rates determined by ponding in large areas are considered most reliable, but the high cost usually dictates that infiltrometer rings, preferably 2 feet in diameter or larger, be used. The hydrology of subsurface materials is critical in the study of infiltration. The zone controlling the rate of infiltration is usually the least permeable zone. Many other factors affect infiltration rate--the sediment (soil) structure, the condition of the sediment surface, the distribution of soil moisture or soil- moisture tension, the chemical and physical nature of the sediments, the head of applied water, the depth to ground water, the chemical quality and the turbidity of the applied water, the temperature of the water and the sediments, the percentage of entrapped air in the sediments, the atmospheric pressure, the length of time of application of water, the biological activity in the sediments, and the type of equipment or method used. It is concluded that specific values of the infiltration rate for a particular type of sediment are probably nonexistent and that measured rates are primarily for comparative use. A standard field-test method for determining infiltration rates by means of single- or double-ring infiltrometers is described and the construction, installation, and operation of the infiltrometers are discussed in detail.

  20. Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate--The effects of street sweeping, vacuum cleaning, high pressure washing, and milling.

    PubMed

    Winston, Ryan J; Al-Rubaei, Ahmed M; Blecken, Godecke T; Viklander, Maria; Hunt, William F

    2016-03-15

    The surface infiltration rates (SIR) of permeable pavements decline with time as sediment and debris clog pore spaces. Effective maintenance techniques are needed to ensure the hydraulic functionality and water quality benefits of this stormwater control. Eight different small-scale and full-scale maintenance techniques aimed at recovering pavement permeability were evaluated at ten different permeable pavement sites in the USA and Sweden. Maintenance techniques included manual removal of the upper 2 cm of fill material, mechanical street sweeping, regenerative-air street sweeping, vacuum street sweeping, hand-held vacuuming, high pressure washing, and milling of porous asphalt. The removal of the upper 2 cm of clogging material did not significantly improve the SIR of concrete grid paves (CGP) and permeable interlocking concrete pavers (PICP) due to the inclusion of fines in the joint and bedding stone during construction, suggesting routine maintenance cannot overcome improper construction. For porous asphalt maintenance, industrial hand-held vacuum cleaning, pressure washing, and milling were increasingly successful at recovering the SIR. Milling to a depth of 2.5 cm nearly restored the SIR for a 21-year old porous asphalt pavement to like-new conditions. For PICP, street sweepers employing suction were shown to be preferable to mechanical sweepers; additionally, maintenance efforts may become more intensive over time to maintain a threshold SIR, as maintenance was not 100% effective at removing clogging material.

  1. Forecasting Foreign Currency Exchange Rates for Air Force Budgeting

    DTIC Science & Technology

    2015-03-26

    Department of Systems Engineering and Management Graduate School of Engineering and Management Air Force Institute of Technology Air University Air...this thesis: the Federal Reserve Foreign Exchange Rate – H.10, the Global Insight forecasts, the Chicago Mercantile Exchange (CME) as taken through...foreign currency units per U.S. dollar for each day of the previous week (Board of Governors of the Federal Reserve System , 2015). Table 3 is a

  2. Position paper -- Tank ventilation system design air flow rates

    SciTech Connect

    Goolsby, G.K.

    1995-01-04

    The purpose of this paper is to document a project position on required ventilation system design air flow rates for the waste storage tanks currently being designed by project W-236A, the Multi-Function Waste Tank Facility (MWTF). The Title 1 design primary tank heat removal system consists of two systems: a primary tank vapor space ventilation system; and an annulus ventilation system. At the conclusion of Title 1 design, air flow rates for the primary and annulus ventilation systems were 960 scfm and 4,400 scfm, respectively, per tank. These design flow rates were capable of removing 1,250,000 Btu/hr from each tank. However, recently completed and ongoing studies have resulted in a design change to reduce the extreme case heat load to 700,000 Btu/hr. This revision of the extreme case heat load, coupled with results of scale model evaporative testing performed by WHC Thermal Hydraulics, allow for a reduction of the design air flow rates for both primary and annulus ventilation systems. Based on the preceding discussion, ICF Kaiser Hanford Co. concludes that the design should incorporate the following design air flow rates: Primary ventilation system--500 scfm maximum and Annulus ventilation system--1,100 scfm maximum. In addition, the minimum air flow rates in the primary and annulus ventilation systems will be investigated during Title 2 design. The results of the Title 2 investigation will determine the range of available temperature control using variable air flows to both ventilation systems.

  3. Honeybee flight metabolic rate: does it depend upon air temperature?

    PubMed

    Woods, William A; Heinrich, Bernd; Stevenson, Robert D

    2005-03-01

    Differing conclusions have been reached as to how or whether varying heat production has a thermoregulatory function in flying honeybees Apis mellifera. We investigated the effects of air temperature on flight metabolic rate, water loss, wingbeat frequency, body segment temperatures and behavior of honeybees flying in transparent containment outdoors. For periods of voluntary, uninterrupted, self-sustaining flight, metabolic rate was independent of air temperature between 19 and 37 degrees C. Thorax temperatures (T(th)) were very stable, with a slope of thorax temperature on air temperature of 0.18. Evaporative heat loss increased from 51 mW g(-1) at 25 degrees C to 158 mW g(-1) at 37 degrees C and appeared to account for head and abdomen temperature excess falling sharply over the same air temperature range. As air temperature increased from 19 to 37 degrees C, wingbeat frequency showed a slight but significant increase, and metabolic expenditure per wingbeat showed a corresponding slight but significant decrease. Bees spent an average of 52% of the measurement period in flight, with 19 of 78 bees sustaining uninterrupted voluntary flight for periods of >1 min. The fraction of time spent flying declined as air temperature increased. As the fraction of time spent flying decreased, the slope of metabolic rate on air temperature became more steeply negative, and was significant for bees flying less than 80% of the time. In a separate experiment, there was a significant inverse relationship of metabolic rate and air temperature for bees requiring frequent or constant agitation to remain airborne, but no dependence for bees that flew with little or no agitation; bees were less likely to require agitation during outdoor than indoor measurements. A recent hypothesis explaining differences between studies in the slope of flight metabolic rate on air temperature in terms of differences in metabolic capacity and thorax temperature is supported for honeybees in voluntary

  4. Water filtration rate and infiltration/accumulation of low density lipoproteins in 3 different modes of endothelial/smooth muscle cell co-cultures.

    PubMed

    Ding, ZuFeng; Fan, YuBo; Deng, XiaoYan

    2009-11-01

    Using different endothelial/smooth muscle cell co-culture modes to simulate the intimal structure of blood vessels, the water filtration rate and the infiltration/accumulation of LDL of the cultured cell layers were studied. The three cell culture modes of the study were: (i) The endothelial cell monolayer (EC/Phi); (ii) endothelial cells directly co-cultured on the smooth muscle cell monolayer (EC-SMC); (iii) endothelial cells and smooth muscle cells cultured on different sides of a Millicell-CM membrane (EC/SMC). It was found that under the same condition, the water filtration rate was the lowest for the EC/SMC mode and the highest for the EC/Phi mode, while the infiltration/accumulation of DiI-LDLs was the lowest in the EC/Phi mode and the highest in the EC-SMC mode. It was also found that DiI-LDL infiltration/accumulation in the cultured cell layers increased with the increasing water filtration rate. The results from the in vitro model study therefore suggest that the infiltration/accumulation of the lipids within the arterial wall is positively correlated with concentration polarization of atherogenic lipids, and the integrity of the endothelium plays an important role in the penetration and accumulation of atherogenic lipids in blood vessel walls.

  5. Design and Implementation of Automatic Air Flow Rate Control System

    NASA Astrophysics Data System (ADS)

    Akbar, A.; Saputra, C.; Munir, M. M.; Khairurrijal

    2016-08-01

    Venturimeter is an apparatus that can be used to measure the air flow rate. In this experiment we designed a venturimeter which equipped with a valve that is used to control the air flow rate. The difference of pressure between the cross sections was measured with the differential pressure sensor GA 100-015WD which can calculate the difference of pressures from 0 to 3737.33 Pa. A 42M048C Z36 stepper motor was used to control the valve. The precision of this motor rotation is about 0.15 °. A Graphical User Interface (GUI) was developed to monitor and set the value of flow rate then an 8-bit microcontroller was used to process the control system In this experiment- the venturimeter has been examined to get the optimal parameter of controller. The results show that the controller can set the stable output air flow rate.

  6. Measuring Outdoor Air Intake Rates into Existing Building

    SciTech Connect

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2009-04-16

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10 percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15 percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  7. High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to

  8. Impacts of Changes of Indoor Air Pressure and Air Exchange Rate in Vapor Intrusion Scenarios.

    PubMed

    Shen, Rui; Suuberg, Eric M

    2016-02-01

    There has, in recent years, been increasing interest in understanding the transport processes of relevance in vapor intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant vapor concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in vapor intrusion situations, including the indoor air pressure and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air pressure and air exchange rate are seen to contribute to significant variations in indoor air contaminant vapor concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures.

  9. Impacts of Changes of Indoor Air Pressure and Air Exchange Rate in Vapor Intrusion Scenarios

    PubMed Central

    Shen, Rui; Suuberg, Eric M.

    2016-01-01

    There has, in recent years, been increasing interest in understanding the transport processes of relevance in vapor intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant vapor concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in vapor intrusion situations, including the indoor air pressure and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air pressure and air exchange rate are seen to contribute to significant variations in indoor air contaminant vapor concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures. PMID:28090133

  10. Yaw rate control of an air bearing vehicle

    NASA Technical Reports Server (NTRS)

    Walcott, Bruce L.

    1989-01-01

    The results of a 6 week project which focused on the problem of controlling the yaw (rotational) rate the air bearing vehicle used on NASA's flat floor facility are summarized. Contained within is a listing of the equipment available for task completion and an evaluation of the suitability of this equipment. The identification (modeling) process of the air bearing vehicle is detailed as well as the subsequent closed-loop control strategy. The effectiveness of the solution is discussed and further recommendations are included.

  11. Versatile radar measurement of the electron loss rate in air

    NASA Astrophysics Data System (ADS)

    Dogariu, Arthur; Shneider, Mikhail N.; Miles, Richard B.

    2013-11-01

    We present an experimental method that makes possible in-situ measurements of the electron loss rate in arbitrary gas mixtures. A weakly ionized plasma is induced via resonant multiphoton ionization of trace amounts of nitric oxide seeded into the gas, and homodyne microwave scattering detection is used to study the dynamics of the electron loss mechanisms. Using this approach, the attachment rate for electrons to molecular oxygen in room temperature, atmospheric pressure air is determined. The measured 0.76 × 108 s-1 attachment rate is in very good agreement with predictions based on literature data.

  12. Versatile radar measurement of the electron loss rate in air

    SciTech Connect

    Dogariu, Arthur; Shneider, Mikhail N.; Miles, Richard B.

    2013-11-25

    We present an experimental method that makes possible in-situ measurements of the electron loss rate in arbitrary gas mixtures. A weakly ionized plasma is induced via resonant multiphoton ionization of trace amounts of nitric oxide seeded into the gas, and homodyne microwave scattering detection is used to study the dynamics of the electron loss mechanisms. Using this approach, the attachment rate for electrons to molecular oxygen in room temperature, atmospheric pressure air is determined. The measured 0.76 × 10{sup 8} s{sup −1} attachment rate is in very good agreement with predictions based on literature data.

  13. Air traffic control surveillance accuracy and update rate study

    NASA Technical Reports Server (NTRS)

    Craigie, J. H.; Morrison, D. D.; Zipper, I.

    1973-01-01

    The results of an air traffic control surveillance accuracy and update rate study are presented. The objective of the study was to establish quantitative relationships between the surveillance accuracies, update rates, and the communication load associated with the tactical control of aircraft for conflict resolution. The relationships are established for typical types of aircraft, phases of flight, and types of airspace. Specific cases are analyzed to determine the surveillance accuracies and update rates required to prevent two aircraft from approaching each other too closely.

  14. A review of air exchange rate models for air pollution exposure assessments.

    PubMed

    Breen, Michael S; Schultz, Bradley D; Sohn, Michael D; Long, Thomas; Langstaff, John; Williams, Ronald; Isaacs, Kristin; Meng, Qing Yu; Stallings, Casson; Smith, Luther

    2014-11-01

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings where people spend their time. The AER, which is the rate of exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pollutants and for removal of indoor-emitted air pollutants. This paper presents an overview and critical analysis of the scientific literature on empirical and physically based AER models for residential and commercial buildings; the models highlighted here are feasible for exposure assessments as extensive inputs are not required. Models are included for the three types of airflows that can occur across building envelopes: leakage, natural ventilation, and mechanical ventilation. Guidance is provided to select the preferable AER model based on available data, desired temporal resolution, types of airflows, and types of buildings included in the exposure assessment. For exposure assessments with some limited building leakage or AER measurements, strategies are described to reduce AER model uncertainty. This review will facilitate the selection of AER models in support of air pollution exposure assessments.

  15. Air Controlman 3 and 2: Naval Rate Training Manual and Nonresident Career Course.

    ERIC Educational Resources Information Center

    Naval Education and Training Command, Pensacola, FL.

    The Rate Training Manual is one of a series of training manuals prepared for enlisted personnel of the Navy and Naval Reserve studying for advancement in the Air Controlman (AC) rating to Air Controlman Third and Second Class. Chapter 1 discusses air controlman qualifications, the enlisted rating structure, the Air Controlman rating, references…

  16. Modeling Spatial and Temporal Variability of Residential Air Exchange Rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

    EPA Science Inventory

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. Th...

  17. Zero-Spring-Rate Mechanism/Air Suspension Cart

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Cooley, Victor M.

    1991-01-01

    Compact mechanism suspends articulating flexible structures with minimal constraints. Zero-spring-rate mechanism (ZSRM) air suspension cart used to suspend flexible, "mass-critical" articles like lightweight spacecraft undergoing such large motions as slewing, translation, and telescoping/retraction. Suspends flexible article undergoing large rigid-body motion concurrent with vibratory motion, with minimal interaction between suspended article and suspending hardware. Adaptive to active control, which reduces undesirable effects caused by friction, nonlinearity, and mass coupling. Practical for most suspension applications.

  18. Air exchange rates in new energy-efficient manufactured housing

    SciTech Connect

    Hadley, D.; Bailey, S.

    1990-10-01

    During the 1989--1990 heating season, Pacific Northwest Laboratory, for the Bonneville Power Administration, measured the ventilation characteristics of 139 newly constructed energy-efficient manufactured homes and a control sample of 35 newer manufactured homes. A standard door fan pressurization technique was used to estimate shell leakiness, and a passive perfluorocarbon tracer technique was used to estimate overall air exchange rates. A measurement of the designated whole-house exhaust system flow rate was taken as well as an occupant and structure survey. The energy-efficient manufactured homes have very low air exchange rates, significantly lower than either existing manufactured homes or site-built homes. The standard deviation of the effective leakage area for this sample of homes is small (25% to 30% of the mean), indicating that the leakiness of manufactured housing stock can be confidently characterized by the mean value. There is some indication of increased ventilation due to the energy-efficient whole-house ventilation specification, but not directly related to the operation of the whole-house system. The mechanical systems as installed and operated do not provide the intended ventilation; consequently indoor air quality could possibly be adversely impacted and moisture/condensation in the living space is a potential problem. 6 refs., 6 figs., 5 tabs.

  19. On the physics of unstable infiltration, seepage, and gravity drainage in partially saturated tuffs

    SciTech Connect

    Faybishenko, B.; Bodvarsson, G.S.; Salve, R.

    2002-04-01

    To improve understanding of the physics of dynamic instabilities in unsaturated flow processes within the Paintbrush nonwelded unit (PTn) and the middle nonlithophysal portion of the Tonopah Spring welded tuff unit (TSw) of Yucca Mountain, we analyzed data from a series of infiltration tests carried out at two sites (Alcove 4 and Alcove 6) in the Exploratory Studies Facility, using analytical and empirical functions. The analysis of infiltration rates measured at both sites showed three temporal scales of infiltration rate: (1) a macro-scale trend of overall decreasing flow, (2) a meso-scale trend of fast and slow motion exhibiting three-stage variations of the flow rate (decreasing, increasing, and [again] decreasing flow rate, as observed in soils in the presence of entrapped air), and (3) micro-scale (high frequency) fluctuations. Infiltration tests in the nonwelded unit at Alcove 4 indicate that this unit may effectively dampen episodic fast infiltration events; however, well-known Kostyakov, Horton, and Philip equations do not satisfactorily describe the observed trends of the infiltration rate. Instead, a Weibull distribution model can most accurately describe experimentally determined time trends of the infiltration rate. Infiltration tests in highly permeable, fractured, welded tuff at Alcove 6 indicate that the infiltration rate exhibits pulsation, which may have been caused by multiple threshold effects and water-air redistribution between fractures and matrix. The empirical relationships between the extrinsic seepage from fractures, matrix imbibition, and gravity drainage versus the infiltration rate, as well as scaling and self-similarity for the leading edge of the water front are the hallmark of the nonlinear dynamic processes in water flow under episodic infiltration through fractured tuff. Based on the analysis of experimental data, we propose a conceptual model of a dynamic fracture flow and fracture-matrix interaction in fractured tuff

  20. Modeling Spatial and Temporal Variability of Residential Air Exchange Rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

    PubMed Central

    Breen, Michael S.; Burke, Janet M.; Batterman, Stuart A.; Vette, Alan F.; Godwin, Christopher; Croghan, Carry W.; Schultz, Bradley D.; Long, Thomas C.

    2014-01-01

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. The residential air exchange rate (AER), which is the rate of exchange of indoor air with outdoor air, is an important determinant for house-to-house (spatial) and temporal variations of air pollution infiltration. Our goal was to evaluate and apply mechanistic models to predict AERs for 213 homes in the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS), a cohort study of traffic-related air pollution exposures and respiratory effects in asthmatic children living near major roads in Detroit, Michigan. We used a previously developed model (LBL), which predicts AER from meteorology and questionnaire data on building characteristics related to air leakage, and an extended version of this model (LBLX) that includes natural ventilation from open windows. As a critical and novel aspect of our AER modeling approach, we performed a cross validation, which included both parameter estimation (i.e., model calibration) and model evaluation, based on daily AER measurements from a subset of 24 study homes on five consecutive days during two seasons. The measured AER varied between 0.09 and 3.48 h−1 with a median of 0.64 h−1. For the individual model-predicted and measured AER, the median absolute difference was 29% (0.19 h‑1) for both the LBL and LBLX models. The LBL and LBLX models predicted 59% and 61% of the variance in the AER, respectively. Daily AER predictions for all 213 homes during the three year study (2010–2012) showed considerable house-to-house variations from building leakage differences, and temporal variations from outdoor temperature and wind speed fluctuations. Using this novel approach, NEXUS will be one of the first epidemiology studies to apply calibrated

  1. Modeling spatial and temporal variability of residential air exchange rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS).

    PubMed

    Breen, Michael S; Burke, Janet M; Batterman, Stuart A; Vette, Alan F; Godwin, Christopher; Croghan, Carry W; Schultz, Bradley D; Long, Thomas C

    2014-11-07

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. The residential air exchange rate (AER), which is the rate of exchange of indoor air with outdoor air, is an important determinant for house-to-house (spatial) and temporal variations of air pollution infiltration. Our goal was to evaluate and apply mechanistic models to predict AERs for 213 homes in the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS), a cohort study of traffic-related air pollution exposures and respiratory effects in asthmatic children living near major roads in Detroit, Michigan. We used a previously developed model (LBL), which predicts AER from meteorology and questionnaire data on building characteristics related to air leakage, and an extended version of this model (LBLX) that includes natural ventilation from open windows. As a critical and novel aspect of our AER modeling approach, we performed a cross validation, which included both parameter estimation (i.e., model calibration) and model evaluation, based on daily AER measurements from a subset of 24 study homes on five consecutive days during two seasons. The measured AER varied between 0.09 and 3.48 h(-1) with a median of 0.64 h(-1). For the individual model-predicted and measured AER, the median absolute difference was 29% (0.19 h‑1) for both the LBL and LBLX models. The LBL and LBLX models predicted 59% and 61% of the variance in the AER, respectively. Daily AER predictions for all 213 homes during the three year study (2010-2012) showed considerable house-to-house variations from building leakage differences, and temporal variations from outdoor temperature and wind speed fluctuations. Using this novel approach, NEXUS will be one of the first epidemiology studies to apply calibrated and

  2. Infiltration in Swelling Soils

    NASA Astrophysics Data System (ADS)

    Giraldez, Juan V.; Sposito, Garrison

    1985-01-01

    Infiltration phenomena in swelling soils were investigated theoretically. The approach taken consisted of applying both the approximate analytical techniques developed by J.-Y. Parlange and co-workers and conventional finite difference numerical methods to study the generalized Richards equation for one-dimensional infiltration in a swelling soil. Equations were derived for the ponding time and the post-ponding infiltration rate that are generalizations of the Parlange-Smith model expressions for rigid soils. Ponding times for swelling soils were shown to be shorter than those for nonswelling analogs, and post-ponding infiltration rates in swelling soils were shown to approach zero instead of becoming equal to the hydraulic conductivity, as in rigid soils. These results were confirmed, both qualitatively and quantitatively, with the numerical model, which also provided instantaneous moisture profiles and surface swelling predictions in agreement with field observations. A three-parameter infiltration equation proposed recently by J.-Y. Parlange et al. (1982) was generalized to describe swelling soils and shown to be in good agreement with published laboratory and field data. It appears that the generalized analytical model equations developed can be employed conveniently in hydrologic applications which do not require high accuracy in predictions.

  3. Escherichia coli removal in biochar-augmented biofilter: effect of infiltration rate, initial bacterial concentration, biochar particle size, and presence of compost.

    PubMed

    Mohanty, Sanjay K; Boehm, Alexandria B

    2014-10-07

    Bioretention systems and biofilters are used in low impact development to passively treat urban stormwater. However, these engineered natural systems are not efficient at removing fecal indicator bacteria, the contaminants responsible for a majority of surface water impairments. The present study investigates the efficacy of biochar-augmented model sand biofilters for Escherichia coli removal under a variety of stormwater bacterial concentrations and infiltration rates. Additionally, we test the role of biochar particle size and "presence of compost on model" biofilter performance. Our results show that E. coli removal in a biochar-augmented sand biofilter is ∼ 96% and is not greatly affected by increases in stormwater infiltration rates and influent bacterial concentrations, particularly within the ranges expected in field. Removal of fine (<125 μm) biochar particles from the biochar-sand biofilter decreased the removal capacity from 95% to 62%, indicating biochar size is important. Addition of compost to biochar-sand biofilters not only lowered E. coli removal capacity but also increased the mobilization of deposited bacteria during intermittent infiltration. This result is attributed to exhaustion of attachment sites on biochar by the dissolved organic carbon leached from compost. Overall, our study indicates that biochar has potential to remove bacteria from stormwater under a wide range of field conditions, but for biochar to be effective, the size should be small and biochar should be applied without compost. Although the results aid in the optimization of biofilter design, further studies are needed to examine biochar potential in the field over an entire rainy season.

  4. IMPACT OF HEATING AND AIR CONDITIONING SYSTEM OPERATION AND LEAKAGE ON VENTILATION AND INTERCOMPARTMENT TRANSPORT: STUDIES IN UNOCCUPIED AND OCCUPIED TENNESSEE VALLEY HOMES

    EPA Science Inventory

    Forced-air heating and air conditioning (HAC) systems caused an average and maximum increase in air infiltration rates of 1.8- and 4.3-fold, respectively, during brief whole-house studies of tracer gas decay In 39 occupied houses. An average Increase in air infiltration rate of 0...

  5. Prototype Systems for Measuring Outdoor Air Intake Rates in Rooftop Air Handlers

    SciTech Connect

    Fisk, William J.; Chan, Wanyu R.; Hotchi, Toshifumi

    2015-01-01

    The widespread absence of systems for real-time measurement and feedback control, of minimum outdoor air intake rates in HVAC systems contributes to the poor control of ventilation rates in commercial buildings. Ventilation rates affect building energy consumption and influence occupant health. The project designed fabricated and tested four prototypes of systems for measuring rates of outdoor air intake into roof top air handlers. All prototypes met the ±20% accuracy target at low wind speeds, with all prototypes accurate within approximately ±10% after application of calibration equations. One prototype met the accuracy target without a calibration. With two of four prototype measurement systems, there was no evidence that wind speed or direction affected accuracy; however, winds speeds were generally below usually 3.5 m s-1 (12.6 km h-1) and further testing is desirable. The airflow resistance of the prototypes was generally less than 35 Pa at maximum RTU air flow rates. A pressure drop of this magnitude will increase fan energy consumption by approximately 4%. The project did not have resources necessary to estimate costs of mass produced systems. The retail cost of components and materials used to construct prototypes ranged from approximately $1,200 to $1,700. The test data indicate that the basic designs developed in this project, particularly the designs of two of the prototypes, have considerable merit. Further design refinement, testing, and cost analysis would be necessary to fully assess commercial potential. The designs and test results will be communicated to the HVAC manufacturing community.

  6. Air exchange rates from atmospheric CO2 daily cycle.

    PubMed

    Carrilho, João Dias; Mateus, Mário; Batterman, Stuart; da Silva, Manuel Gameiro

    2015-04-01

    We propose a new approach for measuring ventilation air exchange rates (AERs). The method belongs to the class of tracer gas techniques, but is formulated in the light of systems theory and signal processing. Unlike conventional CO2 based methods that assume the outdoor ambient CO2 concentration is constant, the proposed method recognizes that photosynthesis and respiration cycle of plants and processes associated with fuel combustion produce daily, quasi-periodic, variations in the ambient CO2 concentrations. These daily variations, which are within the detection range of existing monitoring equipment, are utilized for estimating ventilation rates without the need of a source of CO2 in the building. Using a naturally-ventilated residential apartment, AERs obtained using the new method compared favorably (within 10%) to those obtained using the conventional CO2 decay fitting technique. The new method has the advantages that no tracer gas injection is needed, and high time resolution results are obtained.

  7. Air quality assessment and control of emission rates.

    PubMed

    Skiba, Yuri N; Parra-Guevara, David; Belitskaya, Davydova Valentina

    2005-12-01

    Mathematical methods based on the adjoint model approach are given for the air-pollution estimation and control in an urban region. A simple advection-diffusion-reaction model and its adjoint are used to illustrate the application of the methods. Dual pollution concentration estimates in ecologically important zones are derived and used to develop two non-optimal strategies and one optimal strategy for controlling the emission rates of enterprises. A linear convex combination of these strategies represents a new sufficient strategy. A method for detecting the enterprises, which violate the emission rates prescribed by a control, is given. A method for determining an optimal position for a new enterprise in the region is also described.

  8. Air exchange rates from atmospheric CO2 daily cycle

    PubMed Central

    Carrilho, João Dias; Mateus, Mário; Batterman, Stuart; da Silva, Manuel Gameiro

    2015-01-01

    We propose a new approach for measuring ventilation air exchange rates (AERs). The method belongs to the class of tracer gas techniques, but is formulated in the light of systems theory and signal processing. Unlike conventional CO2 based methods that assume the outdoor ambient CO2 concentration is constant, the proposed method recognizes that photosynthesis and respiration cycle of plants and processes associated with fuel combustion produce daily, quasi-periodic, variations in the ambient CO2 concentrations. These daily variations, which are within the detection range of existing monitoring equipment, are utilized for estimating ventilation rates without the need of a source of CO2 in the building. Using a naturally-ventilated residential apartment, AERs obtained using the new method compared favorably (within 10%) to those obtained using the conventional CO2 decay fitting technique. The new method has the advantages that no tracer gas injection is needed, and high time resolution results are obtained. PMID:26236090

  9. Distribution patterns, infiltration and health risk assessment of PM2.5-bound PAHs in indoor and outdoor air in cold zone.

    PubMed

    Mohammed, Mohammed O A; Song, Wei-Wei; Ma, Yong-Liang; Liu, Li-Yan; Ma, Wan-Li; Li, Wen-Long; Li, Yi-Fan; Wang, Feng-Yan; Qi, Mei-Yun; Lv, Na; Wang, Ding-Zhen; Khan, Afed Ulla

    2016-07-01

    In this study we investigated the distribution patterns, infiltration and health risk assessment of PM2.5-bound PAHs in indoor and outdoor air done in Harbin city, northeastern China. Simultaneous indoor and outdoor sampling was done to collect 264 PM2.5 samples from four sites during winter, summer, and spring. Infiltration of PAHs into indoors was estimated using Retene, Benzo [ghi]perylene and Chrysene as reference compounds, where the latter compound was suggested to be a good estimator and subsequently used for further calculation of infiltration factors (IFs). Modeling with positive matrix factorization (PMF5) and estimation of diagnostic isomeric ratios were applied for identifying sources, where coal combustion, crop residues burning and traffic being the major contributors, particularly during winter. Linear discriminant analysis (LDA) has been utilized to show the distribution patterns of individual PAH congeners. LDA showed that, the greatest seasonal variability was attributed to high molecular weight compounds (HMW PAHs). Potential health risk of PAHs exposure was assessed through relative potency factor approach (RPF). The levels of the sum of 16 US EPA priority PAHs during colder months were very high, with average values of 377 ± 228 ng m(-)(3) and 102 ± 75.8 ng m(-)(3), for the outdoors and indoors, respectively. The outdoor levels reported to be 19 times higher than the outdoor concentrations during warmer months (summer + spring), while the indoor concentrations were suggested to be 9 times and 10 times higher than that for indoor summer (average 11.73 ± 4 ng m(-3)) and indoor spring (9.5 ± 3.3 ng m(-3)). During nighttime, outdoor PAHs revealed wider range of values compared to datytime which was likely due to outdoor temperature, a weather parameter with the strongest negative influence on ∑16PAHs compared to low impact of relative humidity and wind speed.

  10. Effects of hyperbaric oxygen at 1.25 atmospheres absolute with normal air on macrophage number and infiltration during rat skeletal muscle regeneration.

    PubMed

    Fujita, Naoto; Ono, Miharu; Tomioka, Tomoka; Deie, Masataka

    2014-01-01

    Use of mild hyperbaric oxygen less than 2 atmospheres absolute (2026.54 hPa) with normal air is emerging as a common complementary treatment for severe muscle injury. Although hyperbaric oxygen at over 2 atmospheres absolute with 100% O2 promotes healing of skeletal muscle injury, it is not clear whether mild hyperbaric oxygen is equally effective. The purpose of the present study was to investigate the impact of hyperbaric oxygen at 1.25 atmospheres absolute (1266.59 hPa) with normal air on muscle regeneration. The tibialis anterior muscle of male Wistar rats was injured by injection of bupivacaine hydrochloride, and rats were randomly assigned to a hyperbaric oxygen experimental group or to a non-hyperbaric oxygen control group. Immediately after the injection, rats were exposed to hyperbaric oxygen, and the treatment was continued for 28 days. The cross-sectional area of centrally nucleated muscle fibers was significantly larger in rats exposed to hyperbaric oxygen than in controls 5 and 7 days after injury. The number of CD68- or CD68- and CD206-positive cells was significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. Additionally, tumor necrosis factor-α and interleukin-10 mRNA expression levels were significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. The number of Pax7- and MyoD- or MyoD- and myogenin-positive nuclei per mm2 and the expression levels of these proteins were significantly higher in rats exposed to hyperbaric oxygen than in controls 5 days after injury. These results suggest that mild hyperbaric oxygen promotes skeletal muscle regeneration in the early phase after injury, possibly due to reduced hypoxic conditions leading to accelerated macrophage infiltration and phenotype transition. In conclusion, mild hyperbaric oxygen less than 2 atmospheres absolute with normal air is an appropriate support therapy for severe muscle injuries.

  11. Heart-rate monitoring by air pressure and causal analysis

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Naoki; Nakajima, Hiroshi; Hata, Yutaka

    2011-06-01

    Among lots of vital signals, heart-rate (HR) is an important index for diagnose human's health condition. For instance, HR provides an early stage of cardiac disease, autonomic nerve behavior, and so forth. However, currently, HR is measured only in medical checkups and clinical diagnosis during the rested state by using electrocardiograph (ECG). Thus, some serious cardiac events in daily life could be lost. Therefore, a continuous HR monitoring during 24 hours is desired. Considering the use in daily life, the monitoring should be noninvasive and low intrusive. Thus, in this paper, an HR monitoring in sleep by using air pressure sensors is proposed. The HR monitoring is realized by employing the causal analysis among air pressure and HR. The causality is described by employing fuzzy logic. According to the experiment on 7 males at age 22-25 (23 on average), the correlation coefficient against ECG is 0.73-0.97 (0.85 on average). In addition, the cause-effect structure for HR monitoring is arranged by employing causal decomposition, and the arranged causality is applied to HR monitoring in a setting posture. According to the additional experiment on 6 males, the correlation coefficient is 0.66-0.86 (0.76 on average). Therefore, the proposed method is suggested to have enough accuracy and robustness for some daily use cases.

  12. Relativistic collision rate calculations for electron-air interactions

    SciTech Connect

    Graham, G.; Roussel-Dupre, R.

    1992-12-16

    The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 kev. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data is available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two-dimensional grid as a function of mean kinetic energy and thermal energy.

  13. Relativistic collision rate calculations for electron-air interactions

    SciTech Connect

    Graham, G.; Roussel-Dupre, R.

    1993-12-01

    The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 keV. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data are available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two dimensional grid as a function of mean kinetic energy and thermal energy.

  14. Optical detection of intravenous infiltration

    NASA Astrophysics Data System (ADS)

    Winchester, Leonard W.; Chou, Nee-Yin

    2006-02-01

    Infiltration of medications during infusion therapy results in complications ranging from erythema and pain to tissue necrosis requiring amputation. Infiltration occurs from improper insertion of the cannula, separation of the cannula from the vein, penetration of the vein by the cannula during movement, and response of the vein to the medication. At present, visual inspection by the clinical staff is the primary means for detecting intravenous (IV) infiltration. An optical sensor was developed to monitor the needle insertion site for signs of IV infiltration. Initial studies on simulated and induced infiltrations on a swine model validated the feasibility of the methodology. The presence of IV infiltration was confirmed by visual inspection of the infusion site and/or absence of blood return in the IV line. Potential sources of error due to illumination changes, motion artifacts, and edema were also investigated. A comparison of the performance of the optical device and blinded expert observers showed that the optical sensor has higher sensitivity and specificity, and shorter detection time than the expert observers. An improved model of the infiltration monitoring device was developed and evaluated in a clinical study on induced infiltrations of healthy adult volunteers. The performance of the device was compared with the observation of a blinded expert observer. The results show that the rates of detection of infiltrations are 98% and 82% for the optical sensor and the observer, respectively. The sensitivity and specificity of the optical sensor are 0.97 and 0.98, respectively.

  15. Heart rate, heart rate variability and behaviour of horses during air transport.

    PubMed

    Munsters, C C B M; de Gooijer, J-W; van den Broek, J; van Oldruitenborgh-Oosterbaan, M M Sloet

    2013-01-05

    Heart rate (HR), HR variability (HRV) and behaviour score (BS) of nine horses were evaluated during an eight-hour air transport between The Netherlands and New York. HR and HRV parameters were calculated every five minutes during the air transport. Compared with transit (40±3), mean HRs were higher during loading into the jet stall (67±21, P<0.001), loading into the aircraft (47±6, P=0.011), taxiing (50±8, P=0.001), and during periods of in-flight turbulence (46±7, P=0.017). During the flight, individual horses showed differences in mean HR (P=0.005) and peak HR (P<0.001). By contrast with HR data, HRV data did not differ between stages or horses. BS was highest during turbulence (3.2±0.4). However, behaviour did not always correspond with HR measurements: the least responsive horse had the highest HR. Loading into the jet stall caused the highest increase in HR and was considered the most stressful event. During transit, HR was generally comparable with resting rates. Previous studies have shown that loading and transporting by road caused more elevation in HR than during loading and transporting by air. HRV data were not found to be useful, and caution is needed when interpreting HRV data. Not every horse exhibited stress through visible (evasive) behaviour, and HR measurements may provide an additional tool to assess stress in horses.

  16. Linking chloride mass balance infiltration rates with chlorofluorocarbon and SF6 groundwater dating in semi-arid settings: potential and limitations.

    PubMed

    Stadler, Susanne; Osenbruck, Karsten; Duijnisveld, Wilhelmus H M; Schwiede, Martin; Bottcher, Jurgen

    2010-09-01

    In the framework of the investigation of enrichment processes of nitrate in groundwater of the Kalahari of Botswana near Serowe, recharge processes were investigated. The thick unsaturated zone extending to up to 100 m of mostly unconsolidated sediments and very low recharge rates pose a serious challenge to study solute transport related to infiltration and recharge processes, as this extends past the conventional depths of soil scientific investigations and is difficult to describe using evidence from the groundwater due to the limitations imposed by available tracers. To determine the link between nitrate in the vadose zone and in the uppermost groundwater, sediment from the vadose zone was sampled up to a depth of 15-20 m (in one case also to 65 m) on several sites with natural vegetation in the research area. Among other parameters, sediment and water were analysed to determine chloride and nitrate concentration depth profiles. Using the chloride mass balance method, an estimation of groundwater infiltration rates produced values of 0.2-4 mm a(-1). The uncertainty of these values is, however, high. Because of the extreme thickness of the vadose zone, the travel time in the unsaturated zone might reach extreme values of up to 500 years and more. For investigations using groundwater, we applied the chlorofluorocarbons CFC-113, CFC-12, sulphur hexafluoride (SF(6)) and tritium to identify potential recharge, and found indications for some advective transport of the CFCs and SF(6), which we accounted for as constituting potential active localised recharge. In our contribution, we show the potential and limitations of the applied methods to determine groundwater recharge and coupled solute transport in semi-arid settings, and compare travel time ranges derived from soil science and groundwater investigations.

  17. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants.

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  18. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  19. Effect on runoff of rainfall redistribution by the impluvium-shaped canopy of banana cultivated on an Andosol with a high infiltration rate

    NASA Astrophysics Data System (ADS)

    Cattan, P.; Ruy, S. M.; Cabidoche, Y.-M.; Findeling, A.; Desbois, P.; Charlier, J. B.

    2009-04-01

    SummaryRainfall redistribution by plant canopy, notably the water flow down the plant stem (stemflow), modifies the incident rainfall rate at the soil surface and may affect runoff generation. To test this hypothesis, we observed and measured runoff at the plant scale with banana cultivated on tropical Andosol. Observation of runoff by video and matrix potential monitoring showed that, during a runoff event, the matrix potential increased mainly downstream from the pseudostem in line with the slope, delimiting a saturated zone of runoff propagation that appeared on video monitoring. The results indicate that rainfall redistribution by plant canopy, i.e. stemflow and dripping areas, enhances runoff even on soil with a high infiltration rate (mean hydraulic conductivity at saturation Ks of 67 mm h -1). Data analysis of 40 runoff events showed that events were composed of at least two runoff phases characterized by an abrupt increase in runoff coefficient (RC) from 0.16 to 0.65 between the first and the second phase. The change in RC was related to rainfall rate. Also, between the first and the second runoff phase, the apparent infiltration rate at the plot scale decreased from 30 to 10 mm h -1. This was related to an increase in runoff contributing areas (RCA), from an estimated 18% to 93% of the plot surface. However, data analysis and model simulations showed that the increase in mean rainfall rate in RCA due to stemflow was not sufficient to account for large runoff volumes. Hence, one must also take into account the spatial variation of hydraulic conductivity at saturation with low values relative to RCA (estimation for the second runoff phase was 7.6 mm h -1). Moreover, simulation results implied Ks decreases with time. Finally, rainfall redistribution may have an impact at a larger scale. In banana plantations, the hydraulic connectivity of runoff areas can enhance the stemflow effect up to the plot scale. From this point of view, the two-compartment scheme we

  20. Improving Detection of IV Infiltrates in Neonates

    PubMed Central

    Driscoll, MD, Colleen; Langer, Melissa; Burke, Susan; El Metwally, MD, Dina

    2015-01-01

    Neonates and infants in the neonatal intensive care unit suffer significant morbidity when intravenous (IV) catheters infiltrate. The underreporting of adverse events through hospital voluntary reporting systems, such as ours, can complicate the monitoring of low incidence events, like IV infiltrates. Based on severe cases of IV infiltrates observed in our neonatal intensive care unit, we attempted to improve the detection of all infiltrates and reduce the incidence of Stage 4 infiltrates. We developed, and initiated the use of, an evidence-based guideline for the improved surveillance, prevention, and management of IV infiltrates, with corresponding educational interventions for faculty and staff. We instituted the use of a checklist for compliance with guidelines, and as a mechanism of surveillance. The baseline incidence rate of IV infiltrates, determined by the voluntary reporting system, was 5 per 1000 line days. Following initiation of the guidelines and checklist, the IV infiltrate rate increased to 9 per 1000 line days. In most months, the detection of IV infiltrates was improved by use of the checklist. During the post-intervention period the rate of Stage 4 infiltrates, as measured by usage of nitroglycerin ointment, was significantly reduced. In conclusion, the detection of IV infiltrates was improved following our quality improvement interventions. Further, use of an evidence-based guideline for managing infiltrates may reduce the most severe infiltrate injuries. PMID:26734388

  1. Infiltration History and Spatial Variability Derived from Chloride Mass Balance

    NASA Astrophysics Data System (ADS)

    Walton, J. C.; Jaimes, A.; Woocay, A.

    2007-12-01

    Chloride mass balance was applied to drill cuttings collected from the unsaturated zone surrounding the Yucca Mountain Project. Samples correspond to four Nye County Early Warning Drilling Program boreholes where air was used as the drilling fluid to preserve sample integrity. Infiltration dates before present and pore velocities were calculated using a range of annual chloride deposition rates obtained from the literature. The lower chloride loading corresponds to contemporary values, and the upper loading corresponds to an attempt to correct for either past greater chloride deposition or a past higher precipitation with chloride concentration remaining constant. In each borehole, pore velocities present two distinct slopes corresponding to different infiltration regimes. The first one, near the surface, presents the slowest infiltration rate. The second pore velocity corresponds to a past wetter period (late Pleistocene to early Holocene) with much faster pore velocities. Results indicate that pore velocities among the boreholes differ at most by a factor of approximately 3.5. Boreholes located in areas of little or gradual slope present faster infiltration rates than those in areas of greater slope. Borehole NC-EWDP-22S, near Fortymile Wash east of Yucca Mountain, exhibits the most rapid pore velocities where as boreholes further from the wash demonstrate lower velocities. These results denote the effects climate change, and runoff and run-on at the surface have over infiltration rates in arid regions.

  2. Trench infiltration for managed aquifer recharge to permeable bedrock

    USGS Publications Warehouse

    Heilweil, V.M.; Watt, D.E.

    2011-01-01

    Managed aquifer recharge to permeable bedrock is increasingly being utilized to enhance resources and maintain sustainable groundwater development practices. One such target is the Navajo Sandstone, an extensive regional aquifer located throughout the Colorado Plateau of the western United States. Spreading-basin and bank-filtration projects along the sandstone outcrop's western edge in southwestern Utah have recently been implemented to meet growth-related water demands. This paper reports on a new cost-effective surface-infiltration technique utilizing trenches for enhancing managed aquifer recharge to permeable bedrock. A 48-day infiltration trench experiment on outcropping Navajo Sandstone was conducted to evaluate this alternative surface-spreading artificial recharge method. Final infiltration rates through the bottom of the trench were about 0.5 m/day. These infiltration rates were an order of magnitude higher than rates from a previous surface-spreading experiment at the same site. The higher rates were likely caused by a combination of factors including the removal of lower permeability soil and surficial caliche deposits, access to open vertical sandstone fractures, a reduction in physical clogging associated with silt and biofilm layers, minimizing viscosity effects by maintaining isothermal conditions, minimizing chemical clogging caused by carbonate mineral precipitation associated with algal photosynthesis, and diminished gas clogging associated with trapped air and biogenic gases. This pilot study illustrates the viability of trench infiltration for enhancing surface spreading of managed aquifer recharge to permeable bedrock. ?? 2010.

  3. Aleppo pine afforestation in the Massis del Caroig, Eastern Spain. The impact on soil water repellency and infiltration rates.

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; González Pelayo, Óscar; Jordán, Antonio; Mataix Solera, Jorge; Úbeda, Xavier

    2015-04-01

    organic matter content and the production of water repellent substances by the vegetation. Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE supported this research. References Barbera, V., Poma, I., Gristina, L., Novara, A., Egli, M. 2012. Long-term cropping systems and tillage management effects on soil organic carbon stock and steady state level of C sequestration rates in a semiarid environment. Land Degradation & Development, 23: 82- 91. Bellot, J., Maestre, F. T., Chirino, E., Hernández, N., de Urbina, J. O. 2004. Afforestation with< i> Pinus halepensis reduces native shrub performance in a Mediterranean semiarid area. Acta oecologica, 25(1), 7-15. Cerdà, A. & Doerr, S.H. 2007. Soil wettability, runoff and erodibility of major dry-Mediterranean land use types on calcareous soils. Hydrological Processes, 21, 2325-2336. (doi: 10.1016/j.catena.2008.03.010) Cerdà, A. y Doerr, S.H. 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74 , 256- 263. doi:10.1016/S0341-8162(02)00027-9 Chirino, E., Bonet, A., Bellot, J., Sánchez, J. R. 2006. Effects of 30-year-old Aleppo pine plantations on runoff, soil erosion, and plant diversity in a semi-arid landscape in south eastern Spain. Catena, 65(1), 19-29. García-Orenes, F., Cerdà, A., Mataix-Solera, J., Guerrero, C., Bodí, M.B., Arcenegui, V., Zornoza, R. & Sempere, J.G. 2009. Effects of agricultural management on surface soil properties and soil-water losses in eastern Spain. Soil and Tillage Research 106, 117-123. 10.1016/j.still.2009.06.002 García-Orenes, F., Guerrero, C., Roldán, A.,Mataix-Solera, J., Cerdà, A., Campoy, M., Zornoza, R., Bárcenas, G., Caravaca. F. 2010. Soil microbial biomass and activity under different agricultural management systems in a semiarid Mediterranean agroecosystem. Soil and Tillage Research 109, 110-115. 10.1016/j.still.2010.05.005. García-Orenes, F., Roldán, A., Mataix-Solera, J., Cerdà, A

  4. Peer Ratings: Scoring Strategy Development and Reliability Demonstration on Air Force Basic Trainees. Final Report.

    ERIC Educational Resources Information Center

    Borman, Walter C.; Rosse, Rodney L.

    As an alternative for or adjunct to paper-and-pencil tests for predicting personnel performance, the United States Air Force studied the use of peer ratings as an evaluative tool. Purpose of this study was to evaluate the psychometric characteristics of peer ratings among Air Force basic trainees. Peer ratings were obtained from more than 27,000…

  5. Impingement of a drop train enhance the liquid infiltration into a closed end hole

    NASA Astrophysics Data System (ADS)

    Sanada, Toshiyuki; Yamaguchi, Eri; Muraki, Shunsuke

    2016-11-01

    Liquid infiltration is an important process for cleaning inside fine holes. However, it is difficult to infiltrate liquid into closed end holes having small diameter. Because the surface tension prevents the deformation of gas-liquid interface for entering them. In this study we observed the liquid infiltration process into a closed end hole by applying external pressure under two ways, i.e. gradual pressurization with a hand pump and impingement of a droplet train. As a result, it is found that the amount of dissolved air into liquid by applying pressure is small, and it has small effect for the liquid infiltration. In addition, it is also found that the high liquid infiltration rate can be achieved by applying a droplet train impact. It is observed that the trapped bubbles inside the holes were ejected by repetition of droplet impingement.

  6. Statistical analysis of oxidation rates for K Basin fuel in dry air

    SciTech Connect

    Trimble, D.J.

    1998-02-06

    Test data from oxidation of K Basin fuel (SNF) samples in dry air were reviewed, and linear reaction rates were derived on a time-average basis. The derived rates were compared to literature data for unirradiated uranium in dry air using rate law of the form log(rate) = a + b (I/T). The analyses found differences between the SNF data and the literature data. Oxidation rate below 150 C was higher for K Basin fuel than for unirradiated uranium.

  7. Effect of wind tunnel air velocity on VOC flux rates from CAFO manure and wastewater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind tunnels and flux chambers are often used to estimate volatile organic compound (VOC) emissions from animal feeding operations (AFOs) without regard to air velocity or sweep air flow rates. Laboratory experiments were conducted to evaluate the effect of wind tunnel air velocity on VOC emission ...

  8. Investigating Unstable Water Infiltration into Alcohol Contaminated Soils

    NASA Astrophysics Data System (ADS)

    McLeod, H. C.; Smith, J. E.; Henry, E. J.; Brodsky, Y.

    2009-05-01

    A new mechanism causing highly focused, unstable flow exists in soils contaminated with alcohols due to their surface-activity. For example, surface-active compounds can significantly decrease the interfacial tension of the air-water interface and change the pressure-head of the soil water; directly affecting water flow and solute transport in the vadose zone. This study evaluated the fundamental effects of surface-active alcohols on water infiltration into contaminated soils under controlled laboratory conditions. A small scale 3-D glass flow cell and a mini disk tension infiltrometer were used to monitor the rates and physical characteristics of water infiltration from a constant head point source into sands of various textures contaminated with a butanol solution. The results confirmed that water infiltration into these soils is fundamentally and substantially different than the current understanding of infiltration patterns, including previously described mechanisms of wetting front instability. In butanol-contaminated soils, the wetting fronts exhibited highly focused flow with smaller wetted soil volumes, deeper penetration and substantially higher infiltration rates. In addition, the extent of fingered focused flow was confirmed to be texturally dependent, decreasing with grain size and dependent on the constant head boundary. This study characterized a new mechanism of focused, unstable flow with significant implications for groundwater management and solute transport in alcohol contaminated soils.

  9. Effect of air pollution on peak expiratory flow rate variability.

    PubMed

    Singh, Virendra; Khandelwal, Rakesh; Gupta, A B

    2003-02-01

    Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects.

  10. Effects of energy-efficient ventilation rates on indoor air quality at an Ohio elementary school

    NASA Astrophysics Data System (ADS)

    Berk, J. V.; Young, R.; Hollowell, C. D.; Turiel, I.; Pepper, J.

    1980-04-01

    A mobile laboratory was used to monitor air outdoors and at three indoor sites (two classrooms and a large multipurpose room); tests were made at three different ventilation rates. The parameters measured were outside air flow rates, odor perception, microbial burden, particulate mass, total aldehydes, carbon dioxide, ozone, and nitrogen oxides. The results of these measurements are given and compared with the existing outdoor air quality standards. Carbon dioxide concentrations increased as the ventilation rate decreased, but still did not exceed current standards. Odor perceptibility increased slightly at the lowest ventilation rate. Other pollutants showed very low concentrations, which did not change with reductions in ventilation rate.

  11. Root channels to indicate the increase in soil matrix water infiltration capacity of arid reclaimed mine soils

    NASA Astrophysics Data System (ADS)

    Wu, Gao-Lin; Liu, Yu; Yang, Zheng; Cui, Zeng; Deng, Lei; Chang, Xiao-Feng; Shi, Zhi-Hua

    2017-03-01

    Soil matrix flow plays a critical role in redistributing the precipitation input and enhancing water storage in arid areas. Root channels can result in macropore flow which strongly influences soil infiltration. Prior research has addressed the influence of vegetation on erosion and runoff, but the effects of root channels on infiltration capacity are less studied. In this study, we studied the root channels and soil water infiltration rates in ten artificial grasslands in an arid area. The results showed that the average root channel diameter (ARCD) of leguminous grasslands and of shrub grasslands were greater than that of gramineous grasslands (p < 0.05). Importantly, the ARCD and root channel area (RCA) were significantly and positively related to the average infiltration rate in stage I (AIRS I) and the initial infiltration rate (IIR). The IIR and the AIRS I increased at rates of 31.13 and 14.60 mm h-1, respectively, and at the same time there was an increase in ARCD. Overall, our results suggest that root channels played a significant role in the matrix infiltration capacity, resulting in a higher infiltration rate in leguminous grasslands and in mixed sown grasslands than in gramineous grasslands. We suggest that leguminous grasslands or the combination of leguminous and gramineous species in grassland should be given greater attention as suitable materials for mine-soil reclamation in arid regions. Our research improve the understanding of the influence of vegetation on soil hydrological processes and of the hydrology of reclaimed mine soils in arid regions.

  12. Infiltration tests on fractured compacted clay

    SciTech Connect

    McBrayer, M.C.; Mauldon, M.; Drumm, E.C.; Wilson, G.V.

    1997-05-01

    Desiccation and freeze-thaw of compacted clay barriers may result in cracks that serve as preferential flow paths. A series of infiltration tests on compacted kaolin samples was conducted to explore the importance of preferential flow paths during infiltration, and their effect on the infiltration rate. Clod size at the time of compaction was found to have a strong influence on both the rate and depth of infiltration. The authors suggest that flow and infiltration through fractured clay may be described in terms of two stages: an initial dynamic stage in which the infiltration rate is initially high but decreases rapidly due to the clay swelling and closing fractures, and a steady-state stage usually characterized by k{sub sat}, during which the infiltration rate is relatively constant. The study has shown that cracks do not fully heal upon hydration and readily reopen during subsequent dehydration. Infiltration rates during the dynamic stage of infiltration, while cracks are closing, are orders of magnitude higher than the steady-state rate used to estimate k{sub sat}, for barrier evaluation.

  13. Infiltrated carbon foam composites

    NASA Technical Reports Server (NTRS)

    Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

    2012-01-01

    An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

  14. Absorbed dose rate in air in metropolitan Tokyo before the Fukushima Daiichi Nuclear Power Plant accident.

    PubMed

    Inoue, K; Hosoda, M; Fukushi, M; Furukawa, M; Tokonami, S

    2015-11-01

    The monitoring of absorbed dose rate in air has been carried out continually at various locations in metropolitan Tokyo after the accident of the Fukushima Daiichi Nuclear Power Plant. While the data obtained before the accident are needed to more accurately assess the effects of radionuclide contamination from the accident, detailed data for metropolitan Tokyo obtained before the accident have not been reported. A car-borne survey of the absorbed dose rate in air in metropolitan Tokyo was carried out during August to September 2003. The average absorbed dose rate in air in metropolitan Tokyo was 49±6 nGy h(-1). The absorbed dose rate in air in western Tokyo was higher compared with that in central Tokyo. Here, if the absorbed dose rate indoors in Tokyo is equivalent to that outdoors, the annual effective dose would be calculated as 0.32 mSv y(-1).

  15. A MODFLOW Infiltration Device Package for Simulating Storm Water Infiltration.

    PubMed

    Jeppesen, Jan; Christensen, Steen

    2015-01-01

    This article describes a MODFLOW Infiltration Device (INFD) Package that can simulate infiltration devices and their two-way interaction with groundwater. The INFD Package relies on a water balance including inflow of storm water, leakage-like seepage through the device faces, overflow, and change in storage. The water balance for the device can be simulated in multiple INFD time steps within a single MODFLOW time step, and infiltration from the device can be routed through the unsaturated zone to the groundwater table. A benchmark test shows that the INFD Package's analytical solution for stage computes exact results for transient behavior. To achieve similar accuracy by the numerical solution of the MODFLOW Surface-Water Routing (SWR1) Process requires many small time steps. Furthermore, the INFD Package includes an improved representation of flow through the INFD sides that results in lower infiltration rates than simulated by SWR1. The INFD Package is also demonstrated in a transient simulation of a hypothetical catchment where two devices interact differently with groundwater. This simulation demonstrates that device and groundwater interaction depends on the thickness of the unsaturated zone because a shallow groundwater table (a likely result from storm water infiltration itself) may occupy retention volume, whereas a thick unsaturated zone may cause a phase shift and a change of amplitude in groundwater table response to a change of infiltration. We thus find that the INFD Package accommodates the simulation of infiltration devices and groundwater in an integrated manner on small as well as large spatial and temporal scales.

  16. A Review of the Thermodynamic, Transport, and Chemical Reaction Rate Properties of High-temperature Air

    NASA Technical Reports Server (NTRS)

    Hansen, C Frederick; Heims, Steve P

    1958-01-01

    Thermodynamic and transport properties of high temperature air, and the reaction rates for the important chemical processes which occur in air, are reviewed. Semiempirical, analytic expressions are presented for thermodynamic and transport properties of air. Examples are given illustrating the use of these properties to evaluate (1) equilibrium conditions following shock waves, (2) stagnation region heat flux to a blunt high-speed body, and (3) some chemical relaxation lengths in stagnation region flow.

  17. Effect of air-flow rate and turning frequency on bio-drying of dewatered sludge.

    PubMed

    Zhao, Ling; Gu, Wei-Mei; He, Pin-Jing; Shao, Li-Ming

    2010-12-01

    Sludge bio-drying is an approach for biomass energy utilization, in which sludge is dried by means of the heat generated by aerobic degradation of its organic substances. The study aimed at investigating the interactive influence of air-flow rate and turning frequency on water removal and biomass energy utilization. Results showed that a higher air-flow rate (0.0909m(3)h(-1)kg(-1)) led to lower temperature than did the lower one (0.0455m(3)h(-1)kg(-1)) by 17.0% and 13.7% under turning per two days and four days. With the higher air-flow rate and lower turning frequency, temperature cumulation was almost similar to that with the lower air-flow rate and higher turning frequency. The doubled air-flow rate improved the total water removal ratio by 2.86% (19.5gkg(-1) initial water) and 11.5% (75.0gkg(-1) initial water) with turning per two days and four days respectively, indicating that there was no remarkable advantage for water removal with high air-flow rate, especially with high turning frequency. The heat used for evaporation was 60.6-72.6% of the total heat consumption (34,400-45,400kJ). The higher air-flow rate enhanced volatile solids (VS) degradation thus improving heat generation by 1.95% (800kJ) and 8.96% (3200kJ) with turning per two days and four days. With the higher air-flow rate, heat consumed by sensible heat of inlet air and heat utilization efficiency for evaporation was higher than the lower one. With the higher turning frequency, sensible heat of materials and heat consumed by turning was higher than lower one.

  18. Modeling exposure close to air pollution sources in naturally ventilated residences: association of turbulent diffusion coefficient with air change rate.

    PubMed

    Cheng, Kai-Chung; Acevedo-Bolton, Viviana; Jiang, Ruo-Ting; Klepeis, Neil E; Ott, Wayne R; Fringer, Oliver B; Hildemann, Lynn M

    2011-05-01

    For modeling exposure close to an indoor air pollution source, an isotropic turbulent diffusion coefficient is used to represent the average spread of emissions. However, its magnitude indoors has been difficult to assess experimentally due to limitations in the number of monitors available. We used 30-37 real-time monitors to simultaneously measure CO at different angles and distances from a continuous indoor point source. For 11 experiments involving two houses, with natural ventilation conditions ranging from <0.2 to >5 air changes per h, an eddy diffusion model was used to estimate the turbulent diffusion coefficients, which ranged from 0.001 to 0.013 m² s⁻¹. The model reproduced observed concentrations with reasonable accuracy over radial distances of 0.25-5.0 m. The air change rate, as measured using a SF₆ tracer gas release, showed a significant positive linear correlation with the air mixing rate, defined as the turbulent diffusion coefficient divided by a squared length scale representing the room size. The ability to estimate the indoor turbulent diffusion coefficient using two readily measurable parameters (air change rate and room dimensions) is useful for accurately modeling exposures in close proximity to an indoor pollution source.

  19. Horizontal Fluid Infiltration: A New Measurement Device and Some Observations

    NASA Astrophysics Data System (ADS)

    Culligan, P. J.; Ivanov, V. M.; Germiane, J. T.

    2003-12-01

    Fluid infiltration in the vadose zone has been the subject of study since the early 1900s. Understanding infiltration processes is important to numerous problems, including forecasting moisture distribution following soil irrigation, estimating the potential for leachate generation during landfill cover design, and predicting contaminant transport to groundwater following a surface spill. Many models have been developed to describe fluid infiltration, including the well-known models by Jean-Yves Parlange and his co-workers (e.g., Smith and Parlange, Water Resources Research, 14(3), 1978). These models predict the time-rate of infiltration and the cumulative volume of infiltration based on parameters, such as sorptivity, that are often obtained from laboratory experiments. The proper design of these experiments, and appreciation of the factors controlling parameters derived from them, is therefore key to the accuracy of such models. This paper describes a new experimental setup to observe fluid infiltration under one-dimensional capillary dominated flow. Dry soil is packed in a horizontal 700 mm long polycarbonate channel that is 25.5 mm x 25.5 mm in cross-section. The top of the channel is open to the atmosphere. The upstream end of the channel is connected, via a three-valve chamber, to an infiltrant container placed on an electronic balance. Initial flooding and final draining of the three-valve chamber can be controlled without disturbing conditions in the column. The height of the infiltrant container can be adjusted to control the fluid inlet head. The end of the column is capped with a seal that allows the free exit of air. During an experiment, fluid is introduced at the upstream end of the column at a fixed head. The position of the infiltration front and the cumulative mass of fluid flowing into the column are both observed with time. At the end of each experiment, the fluid saturation along the column is obtained by sampling from the top, open surface of

  20. Temporal Variations of Air Dose Rates in East Fukushima During Japanese Fiscal Years 2012 and 2013.

    PubMed

    Akimoto, Kazuhiro

    2017-01-01

    Temporal variations of ambient air dose rates in eastern Fukushima prefecture during Japanese fiscal years 2012 and 2013 are analyzed. The average overall variation rate of air dose rates in east Fukushima during the examined period is found to be 0.49 (51% down) compared to the theoretically predicted value 0.65 (35% down) based on physical decay of radioactive cesium nuclides. On average, local dose rates declined almost linearly for the relatively short period. Temporal characteristics of air dose rates may be classified into variation rates, peaks, spikes, and oscillations. During the examined period, a typical dose-rate curve formed a long-term peak in summer that lasted one through a few months as well as a long-term spike in winter that lasted likewise. Otherwise, occasional short-term peaks and short-term spikes, in addition to long-term oscillations, were observed. Air dose rates may be effectively modulated at short timescales mainly by precipitation. Moreover, it is likely that winds may oscillate air dose rates due to resuspension of radio-dusts.

  1. Correlation of mutagenic assessment of Houston air particulate extracts in relation to lung cancer mortality rates

    SciTech Connect

    Walker, R.D.; Connor, T.H.; MacDonald, E.J.; Trieff, N.M.; Legator, M.S.; MacKenzie, K.W. Jr.; Dobbins, J.G.

    1982-08-01

    Air particulate extracts from a series of solvents were tested in the Ames mutagen detection system and were found to be mutagenic in varying degrees as a function of the particulate collection site in Houston, Texas. The mutagenicity level at seven sites was compared with age-adjusted mortality rates in the same areas. Significant correlation was found with the lung cancer mortality rates but not with mortality rates for other causes. These findings support the hypothesis of a contribution of urban air particulate to the lung cancer rates. Furthermore, these findings suggest that an index of the mutagenicity of air particulate is a more powerful measure of the human health hazard of air pollution than the traditional indices of particulate concentration.

  2. Refinement of the Air Force Systems Command Production Rate Model

    DTIC Science & Technology

    1989-09-01

    the recommended modified formulations. The relationship between production rate and production ratio has a definite influence on the model’s ability to...1984 7 36 21.954 370.00 1985 8 48 21.017 412.00 A- 3 Table A.2.8 F-15E Cost/Quantity Data Fiscal Year Lot Quntit Recurring Unit Cost LPP 1986 1 60

  3. Spatiotemporally-Resolved Air Exchange Rate as a Modifier of Acute Air Pollution-Related Morbidity

    EPA Science Inventory

    The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EP...

  4. Simplified modeling for infiltration and radon entry

    SciTech Connect

    Sherman, M.H.

    1992-08-01

    Air leakage in the envelopes of residential buildings is the primary mechanism for provided ventilation to those buildings. For radon the same mechanisms that drive the ventilation, drive the radon entry This paper attempts to provide a simplified physical model that can be used to understand the interactions between the building leakage distribution, the forces that drive infiltration and ventilation, and indoor radon concentrations, Combining both ventilation and entry modeling together allows an estimation of Radon concentration and exposure to be made and demonstrates how changes in the envelope or ventilation system would affect it. This paper will develop simplified modeling approaches for estimating both ventilation rate and radon entry rate based on the air tightness of the envelope and the driving forces. These approaches will use conventional leakage values (i.e. effective leakage area ) to quantify the air tightness and include natural and mechanical driving forces. This paper will introduce a simplified parameter, the Radon Leakage Area, that quantifies the resistance to radon entry. To be practical for dwellings, modeling of the occupant exposures to indoor pollutants must be simple to use and not require unreasonable input data. This paper presents the derivation of the simplified physical model, and applies that model to representative situations to explore the tendencies to be expected under different circumstances.

  5. Influence of surficial soil and bedrock on indoor radon in New York State homes. Task 2, Subtask 2 of an investigation of infiltration and indoor air quality in New York State homes

    SciTech Connect

    Kunz, C.

    1989-10-01

    Radon can enter a building from soil and bedrock through cracks or openings in the basement. Extrapolation from data obtained from studies of miners exposed to high concentrations of radon and other carcinogens over long periods indicates that radon gas in the home poses an increased risk of lung cancer. The project was initiated to determine the characteristics of soil and bedrock that contribute to the availability of radon for infiltration into the home, and the feasibility of using soil characteristics in mapping areas at higher risk for above-average indoor radon in New York State. After conducting soil surveys across the State, the researchers choose four areas for further study. Fifteen homes in each area were tested for indoor air concentrations of radon, air infiltration into the home, radon concentrations in the soil, and the permeability of the soil for gas flow. The researchers concluded that these parameters could be combined to obtain a Radon Index Number to predict mean indoor radon levels for a given area with similar soil geology. However, this measure has a limited ability to predict indoor radon levels for a particular home due to variations in construction as well as differences in soil and bedrock.

  6. Variations of the ambient dose equivalent rate in the ground level air.

    PubMed

    Lebedyte, M; Butkus, D; Morkŭnas, G

    2003-01-01

    The ambient dose equivalent rate is caused by ionizing radiation of radionuclides in the atmosphere and on the ground surface as well as by cosmic radiation. Seasonal and diurnal variations of the ambient dose equivalent rate (ADER) in the ground level air are influenced by the concentration of 222Rn daughters. The 222Rn concentration in the ground level atmosphere, in turn, depends on the rate of the 222Rn exhalation from soil and turbulent air mixing. Its diurnal and seasonal variations depend on meteorological conditions. The aim of this study is to estimate the influence of variations of the rate of the 222Rn exhalation from soil and its concentrations in the ground level air on variations of ADER in the ground level air, as well as the dependence of these parameters on meteorological conditions. The 222Rn diffusion coefficient and its exhalation rate in undisturbed loamy soil have been determined. The 222Rn concentration in the soil air and its concentration in the ground level air correlate inversely (correlation coefficient is r = -0.62). The main factors determining the 222Rn exhalation from soil are: the soil temperature (r = 0.64), the difference in temperature of soil and air (r = 0.57), and the precipitation amount (r = 0.50). The intensity of gamma radiation in the ground level air is mostly related to the 222Rn concentration in the air (r = 0.62), while the effect of the exhalation rate from soil is relatively low (r = 0.36). It has been shown that ADER due to 222Rn progeny causes only 7-16% of the total ADER and influences its variation. The comparison of variations of ADER due to 222Rn progeny and the total ADER during several years shows that these parameters correlate positively.

  7. Hereditary Diffuse Infiltrating Retinoblastoma.

    PubMed

    Schedler, Katharina J E; Traine, Peter G; Lohmann, Dietmar R; Haritoglou, Christos; Metz, Klaus A; Rodrigues, Eduardo B

    2016-01-01

    Retinoblastoma is one of the most common childhood cancers. The diffuse infiltrating retinoblastoma is a rare subtype of this neoplasm. The majority of cases of diffuse infiltrating retinoblastoma are unilateral and occur sporadically. Herein we report on a family with three children affected by retinoblastoma, among them one girl with diffuse infiltrating retinoblastoma. This girl was diagnosed at the age of 8 years with a unilateral diffuse infiltrating retinoblastoma. By contrast, the two brothers became clinically apparent in the first 2 years of life with bilateral retinoblastoma. The parents were clinically unremarkable. Genetic analysis of RB1 gene was performed. The girl with diffuse infiltrating RB was found to be heterozygous for an oncogenic mutation in the RB1 gene that was also carried by both brothers and the father of the family. These results show that diffuse infiltrating retinoblastoma can develop on the background of a hereditary predisposition to retinoblastoma.

  8. Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis

    DTIC Science & Technology

    2015-03-26

    required and expected . Additionally, the experience they gather throughout their careers is invaluable to the success of the Air Force and cannot be...The service commitments and career paths tend to be relatively equal within this group, so the attrition behavior was expected to be approximately the... females , given that they are in the same yeargroup, career field, etc. Although the actual reason cannot be determined based on this data, one can attribute

  9. Mixed artificial grasslands with more roots improved mine soil infiltration capacity

    NASA Astrophysics Data System (ADS)

    Wu, Gao-Lin; Yang, Zheng; Cui, Zeng; Liu, Yu; Fang, Nu-Fang; Shi, Zhi-Hua

    2016-04-01

    Soil water is one of the critical limiting factors in achieving sustainable revegetation. Soil infiltration capacity plays a vital role in determining the inputs from precipitation and enhancing water storage, which are important for the maintenance and survival of vegetation patches in arid and semi-arid areas. Our study investigated the effects of different artificial grasslands on soil physical properties and soil infiltration capacity. The artificial grasslands were Medicago sativa, Astragalus adsurgens, Agropyron mongolicum, Lespedeza davurica, Bromus inermis, Hedysarum scoparium, A. mongolicum + Artemisia desertorum, A. adsurgens + A. desertorum and M. sativa + B. inermis. The soil infiltration capacity index (SICI), which was based on the average infiltration rate of stage I (AIRSI) and the average infiltration rate of stage III (AIRS III), was higher (indicating that the infiltration capacity was greater) under the artificial grasslands than that of the bare soil. The SICI of the A. adsurgens + A. desertorum grassland had the highest value (1.48) and bare soil (-0.59) had the lowest value. It was evident that artificial grassland could improve soil infiltration capacity. We also used principal component analysis (PCA) to determine that the main factors that affected SICI were the soil water content at a depth of 20 cm (SWC20), the below-ground root biomasses at depths of 10 and 30 cm (BGB10, BGB30), the capillary porosity at a depth of 10 cm (CP10) and the non-capillary porosity at a depth of 20 cm (NCP20). Our study suggests that the use of Legume-poaceae mixtures and Legume-shrub mixtures to create grasslands provided an effective ecological restoration approach to improve soil infiltration properties due to their greater root biomasses. Furthermore, soil water content, below-ground root biomass, soil capillary porosity and soil non-capillary porosity were the main factors that affect the soil infiltration capacity.

  10. Water-air and soil-air exchange rate of total gaseous mercury measured at background sites

    NASA Astrophysics Data System (ADS)

    Poissant, Laurier; Casimir, Alain

    In order to evaluate and understand the processes of water-air and soil-air exchanges involved at background sites, an intensive field measurement campaign has been achieved during the summer of 1995 using high-time resolution techniques (10 min) at two sites (land and water) in southern Québec (Canada). Mercury flux was measured using a dynamic flux chamber technique coupled with an automatic mercury vapour-phase analyser (namely, Tekran®). The flux chamber shows that the rural grassy site acted primarily as a source of atmospheric mercury, its flux mimicked the solar radiation, with a maximum daytime value of ˜ 8.3 ng m -2 h -1 of TGM. The water surface location (St. Lawrence River site located about 3 km from the land site) shows deposition and evasion fluxes almost in the same order of magnitude (-0.5 vs 1.0 ng m -2 h -1).The latter is influenced to some extent by solar radiation but primarily by the formation of a layer of stable air over the water surface in which some redox reactions might promote evasion processes over the water surface. This process does not appear over the soil surface. As a whole, soil-air exchange rate is about 6-8 fold greater than the water-air exchange.

  11. Air-water Gas Exchange Rates on a Large Impounded River Measured Using Floating Domes (Poster)

    EPA Science Inventory

    Mass balance models of dissolved gases in rivers typically serve as the basis for whole-system estimates of greenhouse gas emission rates. An important component of these models is the exchange of dissolved gases between air and water. Controls on gas exchange rates (K) have be...

  12. K{sub Air} and H*(10) Rate Constants for Gamma Emitters

    SciTech Connect

    Vega-Carrillo, H. R.; Juarez, R. Rodriguez; Manzanares-Acuna, E.; Davila, V. M. Hernandez; Mercado, G. A.

    2008-08-11

    Monte Carlo calculations have been carried out to estimate the Air Kerma rate constant and the Ambient dose equivalent rate constant for 139 monoenergetic photon sources. The factor that relates activity to air kerma rate or to ambient dose equivalent is useful to estimate the dose from a photon emitter source. Here 139 point-like and monoenergetic gamma-ray sources, ranging from 0.01 to 10 MeV were utilized in Monte Carlo calculations to estimate both gamma factors. These factors were utilized to calculate the air kerma-and-ambient dose equivalent rate constants for {sup 137}Cs-{sup 137m}Ba, {sup 198}Au, {sup 60}Co, and {sup 131}I, whose values were compared with those published in the literature.

  13. Entrainment Rate in Shallow Cumuli: Dependence on Entrained Dry Air Sources and Probability Density Functions

    NASA Astrophysics Data System (ADS)

    Lu, C.; Liu, Y.; Niu, S.; Vogelmann, A. M.

    2012-12-01

    In situ aircraft cumulus observations from the RACORO field campaign are used to estimate entrainment rate for individual clouds using a recently developed mixing fraction approach. The entrainment rate is computed based on the observed state of the cloud core and the state of the air that is laterally mixed into the cloud at its edge. The computed entrainment rate decreases when the air is entrained from increasing distance from the cloud core edge; this is because the air farther away from cloud edge is drier than the neighboring air that is within the humid shells around cumulus clouds. Probability density functions of entrainment rate are well fitted by lognormal distributions at different heights above cloud base for different dry air sources (i.e., different source distances from the cloud core edge). Such lognormal distribution functions are appropriate for inclusion into future entrainment rate parameterization in large scale models. To the authors' knowledge, this is the first time that probability density functions of entrainment rate have been obtained in shallow cumulus clouds based on in situ observations. The reason for the wide spread of entrainment rate is that the observed clouds are affected by entrainment mixing processes to different extents, which is verified by the relationships between the entrainment rate and cloud microphysics/dynamics. The entrainment rate is negatively correlated with liquid water content and cloud droplet number concentration due to the dilution and evaporation in entrainment mixing processes. The entrainment rate is positively correlated with relative dispersion (i.e., ratio of standard deviation to mean value) of liquid water content and droplet size distributions, consistent with the theoretical expectation that entrainment mixing processes are responsible for microphysics fluctuations and spectral broadening. The entrainment rate is negatively correlated with vertical velocity and dissipation rate because entrainment

  14. Cooling Rates of Humans in Air and in Water: An Experiment

    NASA Astrophysics Data System (ADS)

    Bohren, Craig F.

    2012-12-01

    In a previous article I analyzed in detail the physical factors resulting in greater cooling rates of objects in still water than in still air, emphasizing cooling of the human body. By cooling rate I mean the rate of decrease of core temperature uncompensated by metabolism. I concluded that the "correct ratio for humans is closer to 2 than to 10." To support this assertion I subsequently did experiments, which I report following a digression on hypothermia.

  15. The rate of pressure rise of gaseous propylene-air explosions in spherical and cylindrical enclosures.

    PubMed

    Razus, Domnina; Movileanua, Codina; Oancea, Dumitru

    2007-01-02

    The maximum rates of pressure rise of propylene-air explosions at various initial pressures and various fuel/oxygen ratios in three closed vessels (a spherical vessel with central ignition and two cylindrical vessels with central or with top ignition) are reported. It was found that in explosions of quiescent mixtures the maximum rates of pressure rise are linear functions on total initial pressure, at constant initial temperature and fuel/oxygen ratio. The slope and intercept of found correlations are greatly influenced by vessel's volume and shape and by the position of the ignition source--factors which determine the amount of heat losses from the burned gas in a closed vessel explosion. Similar data on propylene-air inert mixtures are discussed in comparison with those referring to propylene-air, revealing the influence of nature and amount of inert additive. The deflagration index KG of centrally ignited explosions was also calculated from maximum rates of pressure rise.

  16. Modelling infiltration processes in frozen soils

    NASA Astrophysics Data System (ADS)

    Ireson, A. M.; Barbour, L. S.

    2014-12-01

    Understanding the hydrological processes in soils subject to significant freeze-thaw is fraught by "experimental vagaries and theoretical imponderables" (Miller 1980, Applications of soil physics). The infiltration of snowmelt water and the subsequent transmission of unfrozen water during thawing, is governed by hydraulic conductivity values which are changing with both ice and unfrozen water content. Water held within pores is subject to capillary forces, which results in a freezing point depression (i.e. water remains in the liquid state slightly below 0°C). As the temperature drops below zero, water freezes first in the larger pores, and then in progressively smaller pores. Since the larger pores also are the first to empty by drainage, these pores may be air filled during freezing, while smaller water filled pores freeze. This explains why an unsaturated, frozen soil may still have a considerable infiltration capacity. Infiltration into frozen soil is a critical phenomena related to the risk of flooding in the Canadian prairies, controlling the partitioning of snowmelt into either infiltration or runoff. We propose a new model, based on conceptualizing the pore space as a bundle of capillary tubes (with significant differences to the capillary bundle model of Wannatabe and Flury, 2008, WRR, doi:10.1029/2008WR007102) which allows any air-filled macropores to contribute to the potential infiltration capacity of the soil. The patterns of infiltration and water movement during freeze-thaw from the model are compared to field observations from the Canadian prairies and Boreal Plains.

  17. Air pollutant emission rates for sources at the Deaf Smith County repository site

    SciTech Connect

    Not Available

    1985-11-01

    This document summarizes the air-quality source terms used for the Deaf Smith County, Texas environmental assessment report and explains their derivation. The engineering data supporting these source terms appear as appendixes to this report and include summary equipment lists for the repository and detailed equipment lists for the exploratory shaft. Although substantial work has been performed in establishing the current repository design, a greater effort will be required for the final design. Consequently, the repository emission rates presented here should be considered as preliminary estimates. Another set of air pollution emission rates will be calculated after design data are more firmly established. 18 refs., 15 tabs.

  18. Infiltration in ASHRAE's Residential Ventilation Standards

    SciTech Connect

    Sherman, Max

    2008-10-01

    The purpose of ventilation is to dilute or remove indoor contaminants that an occupant could be exposed to. It can be provided by mechanical or natural means. ASHRAE Standards including standards 62, 119, and 136 have all considered the contribution of infiltration in various ways, using methods and data from 20 years ago. The vast majority of homes in the United States and indeed the world are ventilated through natural means such as infiltration caused by air leakage. Newer homes in the western world are tight and require mechanical ventilation. As we seek to provide acceptable indoor air quality at minimum energy cost, it is important to neither over-ventilate norunder-ventilate. Thus, it becomes critically important to correctly evaluate the contribution infiltration makes to both energy consumption and equivalent ventilation. ASHRAE Standard 62.2 specifies how much mechanical ventilation is considered necessary to provide acceptable indoor air quality, but that standard is weak on how infiltration can contribute towards meeting the total requirement. In the past ASHRAE Standard 136 was used to do this, but new theoretical approaches and expanded weather data have made that standard out of date. This article will describe how to properly treat infiltration as an equivalent ventilation approach and then use new data and these new approaches to demonstrate how these calculations might be done both in general and to update Standard 136.

  19. EFFECT OF AIR-POLLUTION CONTROL ON DEATH RATES IN DUBLIN, IRELAND: AN INTERVENTION STUDY. (R827353C006)

    EPA Science Inventory

    Background Particulate air pollution episodes have been associated with increased daily death. However, there is little direct evidence that diminished particulate air pollution concentrations would lead to reductions in death rates. We assessed the effect of ...

  20. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  1. Effects of saline-water flow rate and air speed on leakage current in RTV coatings

    SciTech Connect

    Kim, S.H.; Hackam, R.

    1995-10-01

    Room temperature vulcanizing (RTV) silicone rubber is increasingly being used to coat porcelain and glass insulators in order to improve their electrical performance in the presence of pollution and moisture. A study of the dependence of leakage current, pulse current count and total charge flowing across the surface of RTV on the flow rate of the saline water and on the compressed air pressure used to create the salt-fog is reported. The fog was directed at the insulating rods either from one or two sides. The RTV was fabricated from polydimethylsiloxane polymer, a filler of alumina trihydrate (ATH), a polymerization catalyst and fumed silica reinforcer, all dispersed in 1,1,1-trichloroethane solvent. The saline water flow rate was varied in the range 0.4 to 2.0 l/min. The compressed air pressure at the input of the fog nozzles was varied from 0.20 to 0.63 MPa. The air speed at the surface of the insulating rods was found to depend linearly on the air pressure measured at the inlet to the nozzles and varied in the range 3 to 14 km/hr. The leakage current increased with increasing flow rate and increasing air speed. This is attributed to the increased loss of hydrophobicity with a larger quantity of saline fog and a larger impact velocities of fog droplets interacting with the surface of the RTV coating.

  2. Contribution of climate and air pollution to variation in coronary heart disease mortality rates in England.

    PubMed

    Scarborough, Peter; Allender, Steven; Rayner, Mike; Goldacre, Michael

    2012-01-01

    There are substantial geographic variations in coronary heart disease (CHD) mortality rates in England that may in part be due to differences in climate and air pollution. An ecological cross-sectional multi-level analysis of male and female CHD mortality rates in all wards in England (1999-2004) was conducted to estimate the relative strength of the association between CHD mortality rates and three aspects of the physical environment--temperature, hours of sunshine and air quality. Models were adjusted for deprivation, an index measuring the healthiness of the lifestyle of populations, and urbanicity. In the fully adjusted model, air quality was not significantly associated with CHD mortality rates, but temperature and sunshine were both significantly negatively associated (p<0.05), suggesting that CHD mortality rates were higher in areas with lower average temperature and hours of sunshine. After adjustment for the unhealthy lifestyle of populations and deprivation, the climate variables explained at least 15% of large scale variation in CHD mortality rates. The results suggest that the climate has a small but significant independent association with CHD mortality rates in England.

  3. Contribution of Climate and Air Pollution to Variation in Coronary Heart Disease Mortality Rates in England

    PubMed Central

    Scarborough, Peter; Allender, Steven; Rayner, Mike; Goldacre, Michael

    2012-01-01

    There are substantial geographic variations in coronary heart disease (CHD) mortality rates in England that may in part be due to differences in climate and air pollution. An ecological cross-sectional multi-level analysis of male and female CHD mortality rates in all wards in England (1999–2004) was conducted to estimate the relative strength of the association between CHD mortality rates and three aspects of the physical environment - temperature, hours of sunshine and air quality. Models were adjusted for deprivation, an index measuring the healthiness of the lifestyle of populations, and urbanicity. In the fully adjusted model, air quality was not significantly associated with CHD mortality rates, but temperature and sunshine were both significantly negatively associated (p<0.05), suggesting that CHD mortality rates were higher in areas with lower average temperature and hours of sunshine. After adjustment for the unhealthy lifestyle of populations and deprivation, the climate variables explained at least 15% of large scale variation in CHD mortality rates. The results suggest that the climate has a small but significant independent association with CHD mortality rates in England. PMID:22427884

  4. Spray deposition inside tree canopies from a newly developed variable-rate air assisted sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional spray applications in orchards and ornamental nurseries are not target-oriented, resulting in significant waste of pesticides and contamination of the environment. To address this problem, a variable-rate air-assisted sprayer implementing laser scanning technology was developed to apply...

  5. THE EFFECT OF OPENING WINDOWS ON AIR CHANGE RATES IN TWO HOMES

    EPA Science Inventory

    Over 300 air change rate experiments were completed in two occupied residences: a two-story detached house in Redwood City, CA and a three-story townhouse in Reston, VA. A continuous monitor was used to measure the decay of sulfur hexafluoride tracer gas over periods of 1 to 1...

  6. Rainier Mesa CAU Infiltration Model using INFILv3

    SciTech Connect

    Levitt, Daniel G.; Kwicklis, Edward M.

    2012-07-13

    The outline of this presentation are: (1) Model Inputs - DEM, Precipitation, Air temp, Soil props, Surface geology, Vegetation; (2) Model Pre-processing - Runoff Routing and sinks, Slope and Azimuth, Soil Ksat reduction with slope (to mitigate bathtub ring), Soil-Bedrock Interface permeabilities; (3) Model Calibration - ET using PEST, Chloride mass balance data, Streamflow using PEST; (4) Model Validation - Streamflow data not used for calibration; (5) Uncertainty Analysis; and (6) Results. Conclusions are: (1) Average annual infiltration rates =11 to 18 mm/year for RM domain; (2) Average annual infiltration rates = 7 to 11 mm/year for SM domain; (3) ET = 70% of precipitation for both domains; (4) Runoff = 8-9% for RM; and 22-24% for SM - Apparently high average runoff is caused by the truncation of the lowerelevation portions of watersheds where much of the infiltration of runoff waters would otherwise occur; (5) Model results are calibrated to measured ET, CMB data, and streamflow observations; (6) Model results are validated using streamflow observations discovered after model calibration was complete; (7) Use of soil Ksat reduction with slope to mitigate bathtub ring was successful (based on calibration results); and (8) Soil-bedrock K{_}interface is innovative approach.

  7. The effects of air pollutants on the mortality rate of lung cancer and leukemia.

    PubMed

    Dehghani, Mansooreh; Keshtgar, Laila; Javaheri, Mohammad Reza; Derakhshan, Zahra; Oliveri Conti, Gea; Zuccarello, Pietro; Ferrante, Margherita

    2017-03-24

    World Health Organization classifies air pollution as the first cause of human cancer. The present study investigated impact of air pollutants on the mortality rates of lung cancer and leukemia in Shiraz, one of the largests cities of Iran. This cross‑sectional (longitudinal) study was carried out in Shiraz. Data on six main pollutants, CO, SO2, O3, NO2, PM10 and PM2.5, were collected from Fars Environmental Protection Agency for 3,001 days starting from 1 January, 2005. Also, measures of climatic factors (temperature, humidity, and air pressure) were obtained from Shiraz Meteorological Organization. Finally, data related to number of deaths due to lung and blood cancers (leukemia) were gathered from Shiraz University Hospital. Relationship between variations of pollutant concentrations and cancers in lung and blood was investigated using statistical software R and MiniTab to perform time series analysis. Results of the present study revealed that the mortality rate of leukemia had a direct significant correlation with concentrations of nitrogen dioxide and carbon monoxide in the air (P<0.05). Therefore, special attention should be paid to sources of these pollutants and we need better management to decrease air pollutant concentrations through, e.g., using clean energy respect to fossil fuels, better management of urban traffic planning, and the improvement of public transport service and car sharing.

  8. Evaluation of the indoor air quality minimum ventilation rate procedure for use in California retail buildings.

    PubMed

    Dutton, S M; Mendell, M J; Chan, W R; Barrios, M; Sidheswaran, M A; Sullivan, D P; Eliseeva, E A; Fisk, W J

    2015-02-01

    This research assesses benefits of adding to California Title-24 ventilation rate (VR) standards a performance-based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers 'Indoor Air Quality Procedure' (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate 'IAQP-based' VRs that would maintain concentrations of all CoCs below health- or odor-based reference concentration limits. An intervention study in a 'big box' store assessed how the current VR, the Title 24-prescribed VR, and the IAQP-based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24-prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP-based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas-phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant-reduction strategies.

  9. [Calculating method for the necessary lamps and sterile rate in a tube-shaped ultraviolet air washer].

    PubMed

    Xu, Z; Chen, C; Shen, J

    1998-05-01

    It has much more advantage to use the cylindric ultraviolet air washer than to use the ordinary ultraviolet lamps. There was a calculation method for determining necessary lamps in a rectangled ultraviolet air washer, but it had a limiting condition. This paper developed two calculating methods for determining necessary lamps and its sterile rate in a tube-shaped ultraviolet air washer. The sterile rate can be extracted with any parameter. Necessary lamps can also be extracted with its sterile rate.

  10. Relationship between recycling rate and air pollution: Waste management in the state of Massachusetts

    SciTech Connect

    Giovanis, Eleftherios

    2015-06-15

    Highlights: • This study examines the relationship between recycling rate of solid waste and air pollution. • Fixed effects Stochastic Frontier Analysis model with panel data are employed. • The case study is a waste municipality survey in the state of Massachusetts during 2009–2012. • The findings support that a negative relationship between air pollution and recycling. - Abstract: This study examines the relationship between recycling rate of solid waste and air pollution using data from a waste municipality survey in the state of Massachusetts during the period 2009–2012. Two econometric approaches are applied. The first approach is a fixed effects model, while the second is a Stochastic Frontier Analysis (SFA) with fixed effects model. The advantage of the first approach is the ability of controlling for stable time invariant characteristics of the municipalities, thereby eliminating potentially large sources of bias. The second approach is applied in order to estimate the technical efficiency and rank of each municipality accordingly. The regressions control for various demographic, economic and recycling services, such as income per capita, population density, unemployment, trash services, Pay-as-you-throw (PAYT) program and meteorological data. The findings support that a negative relationship between particulate particles in the air 2.5 μm or less in size (PM{sub 2.5}) and recycling rate is presented. In addition, the pollution is increased with increases on income per capita up to $23,000–$26,000, while after this point income contributes positively on air quality. Finally, based on the efficiency derived by the Stochastic Frontier Analysis (SFA) model, the municipalities which provide both drop off and curbside services for trash, food and yard waste and the PAYT program present better performance regarding the air quality.

  11. Effect of outside air ventilation rate on VOC concentrations and emissions in a call center

    SciTech Connect

    Hodgson, A.T.; Faulkner, D.; Sullivan, D.P.; DiBartolomeo, D.L.; Russell, M.L.; Fisk, W.J.

    2002-01-01

    A study of the relationship between outside air ventilation rate and concentrations of VOCs generated indoors was conducted in a call center. Ventilation rates were manipulated in the building's four air handling units (AHUs). Concentrations of VOCs in the AHU returns were measured on 7 days during a 13-week period. Indoor minus outdoor concentrations and emission factors were calculated. The emission factor data was subjected to principal component analysis to identify groups of co-varying compounds based on source type. One vector represented emissions of solvents from cleaning products. Another vector identified occupant sources. Direct relationships between ventilation rate and concentrations were not observed for most of the abundant VOCs. This result emphasizes the importance of source control measures for limiting VOC concentrations in buildings.

  12. Comparison of monoenergetic photon organ dose rate coefficients for stylized and voxel phantoms submerged in air

    SciTech Connect

    Bellamy, Michael B.; Hiller, Mauritius M.; Dewji, Shaheen A.; Veinot, Kenneth G.; Leggett, Richard Wayne; Eckerman, Keith F.; Easterly, Clay E.; Hertel, Nolan E.

    2016-02-01

    As part of a broader effort to calculate effective dose rate coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, soil or water, age-specific stylized phantoms have been employed to determine dose coefficients relating dose rate to organs and tissues in the body. In this article, dose rate coefficients computed using the International Commission on Radiological Protection reference adult male voxel phantom are compared with values computed using the Oak Ridge National Laboratory adult male stylized phantom in an air submersion exposure geometry. Monte Carlo calculations for both phantoms were performed for monoenergetic source photons in the range of 30 keV to 5 MeV. Furthermore, these calculations largely result in differences under 10 % for photon energies above 50 keV, and it can be expected that both models show comparable results for the environmental sources of radionuclides.

  13. Comparison of monoenergetic photon organ dose rate coefficients for stylized and voxel phantoms submerged in air

    DOE PAGES

    Bellamy, Michael B.; Hiller, Mauritius M.; Dewji, Shaheen A.; ...

    2016-02-01

    As part of a broader effort to calculate effective dose rate coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, soil or water, age-specific stylized phantoms have been employed to determine dose coefficients relating dose rate to organs and tissues in the body. In this article, dose rate coefficients computed using the International Commission on Radiological Protection reference adult male voxel phantom are compared with values computed using the Oak Ridge National Laboratory adult male stylized phantom in an air submersion exposure geometry. Monte Carlo calculations for both phantoms were performed for monoenergetic source photonsmore » in the range of 30 keV to 5 MeV. Furthermore, these calculations largely result in differences under 10 % for photon energies above 50 keV, and it can be expected that both models show comparable results for the environmental sources of radionuclides.« less

  14. Rate constants for chemical reactions in high-temperature nonequilibrium air

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.

    1986-01-01

    In the nonequilibrium atmospheric chemistry regime that will be encountered by the proposed Aeroassisted Orbital Transfer Vehicle in the upper atmosphere, where air density is too low for thermal and chemical equilibrium to be maintained, the detailed high temperature air chemistry plays a critical role in defining radiative and convective heating loads. Although vibrational and electronic temperatures remain low (less than 15,000 K), rotational and translational temperatures may reach 50,000 K. Attention is presently given to the effects of multiple temperatures on the magnitudes of various chemical reaction rate constants, for the cases of both bimolecular exchange reactions and collisional excitation and dissociation reactions.

  15. Geophysical methods for monitoring infiltration in soil

    NASA Astrophysics Data System (ADS)

    Coquet, Yves; Pessel, Marc; Saintenoy, Albane

    2015-04-01

    Geophysics provides useful tools for monitoring water infiltration in soil essentially because they are non-invasive and have a good time-resolution. We present some results obtained on different soils using two geophysical techniques: electrical resistivity tomography (ERT) and ground-penetrating radar (GPR). Infiltration in a loamy soil was monitored using a 2D Wenner array set up under a tension disc infiltrometer. A good imaging of the infiltration bulb below the infiltrometer could be achieved provided a sufficient resistivity contrast between the wet and the dry soil zones. ERT data could be used to invert soil hydraulic properties. However, we found that the information provided by the ERT could be of limited importance in regard to the information provided by the infiltration rate dynamics if the ERT spatial resolution is not small enough to capture the details of the infiltration front at the limit between the wet and dry soil zones. GPR was found to be a good tool to monitor the progression of the infiltration front in a sandy soil. By combining a water transport simulation model (HYDRUS-1D), a method for transforming water content into dielectric permittivity values (CRIM), and an electromagnetic wave propagation model (GprMax), the Mualem-van Genuchten hydraulic parameters could be retrieved from radargrams obtained under constant or falling head infiltration experiments. Both ERT and GPR methods have pros and cons. Time and spatial resolutions are of prime importance to achieve a sufficient sensitivity to all soil hydraulic parameters. Two exploration fields are suggested: the combination of different geophysical methods to explore infiltration in heterogeneous soils, and the development of integrated infiltrometers that allow geophysical measurements while monitoring water infiltration rate in soil.

  16. Photonic crystal waveguide created by selective infiltration

    NASA Astrophysics Data System (ADS)

    Casas Bedoya, A.; Domachuk, P.; Grillet, C.; Monat, C.; Mägi, E. C.; Li, E.; Eggleton, B. J.

    2012-06-01

    The marriage of photonics and microfluidics ("optofluidics") uses the inherent mobility of fluids to reversibly tune photonic structures beyond traditional fabrication methods by infiltrating voids in said structures. Photonic crystals (PhCs) strongly control light on the wavelength scale and are well suited to optofluidic tuning because their periodic airhole microstructure is a natural candidate for housing liquids. The infiltration of a single row of holes in the PhC matrix modifies the effective refractive index allowing optical modes to be guided by the PhC bandgap. In this work we present the first experimental demonstration of a reconfigurable single mode W1 photonic crystal defect waveguide created by selective liquid infiltration. We modified a hexagonal silicon planar photonic crystal membrane by selectively filling a single row of air holes with ~300nm resolution, using high refractive index ionic liquid. The modification creates optical confinement in the infiltrated region and allows propagation of a single optical waveguide mode. We describe the challenges arising from the infiltration process and the liquid/solid surface interaction in the photonic crystal. We include a detailed comparison between analytic and numerical modeling and experimental results, and introduce a new approach to create an offset photonic crystal cavity by varying the nature of the selective infiltration process.

  17. Association Between Air Temperature and Cancer Death Rates in Florida: An Ecological Study.

    PubMed

    Hart, John

    2015-01-01

    Proponents of global warming predict adverse events due to a slight warming of the planet in the last 100 years. This ecological study tests one of the possible arguments that might support the global warming theory - that it may increase cancer death rates. Thus, average daily air temperature is compared to cancer death rates at the county level in a U.S. state, while controlling for variables of smoking, race, and land elevation. The study revealed that lower cancer death rates were associated with warmer temperatures. Further study is indicated to verify these findings.

  18. Measurement of HOx• production rate due to radon decay in air

    SciTech Connect

    Ding, Huiling

    1993-08-01

    Radon in indoor air may cause the exposure of the public to excessive radioactivity. Radiolysis of water vapor in indoor air due to radon decay could produce (•OH and HO2 •) that may convert atmospheric constituents to compounds of lower vapor pressure. These lower vapor pressure compounds might then nucleate to form new particles in the indoor atmosphere. Chemical amplification was used to determine HOx• production rate in indoor air caused by radon decay. Average HOx• production rate was found to be (4.31±0.07) x 105 HOx• per Rn decay per second (Bq) 3.4 to 55.0% at 22C. This work provided G(HOx•)-value, 7.86±0.13 No./100 eV in air by directly measuring [HOx•] formed from the radiolysis procedure. This G value implies that HOx• produced by radon decay in air might be formed by multiple processes and may be result of positive ion-molecule reactions, primary radiolysis, and radical reactions. There is no obvious relation between HOx• production rate and relative humidity. A laser-induced fluorescence (LIF) system has been used for •OH production rate measurement; it consists of an excimer laser, a dye laser, a frequency doubler, a gaseous fluorescence chamber, and other optical and electronic parts. This system needs to be improved to eliminate the interferences of light scattering and artificial •OH produced from the photolysis of O3/H2O.

  19. Spatial and temporal variations of ponded infiltration in a grid of permanent infiltration rings

    NASA Astrophysics Data System (ADS)

    Votrubová, Jana; Dohnal, Michal; Dušek, Jaromír; Vogel, Tomáš; Tesař, Miroslav; Císlerová, Milena

    2016-04-01

    The soil at Liz experimental site (Volynka headwater catchment, Sumava Mountains, southern Bohemia) has been subject to a long term research on the soil infiltration properties since 2003. For this purpose, 18 permanent infiltration rings were installed at a gently sloped grass-covered experimental plot (300 sq.m). Using this set-up, the single-ring ponded infiltration experiments have been conducted annually. Since 2005, a procedure of repeating the same ponded infiltration experiments in two successive days has been implemented. For the soil type of the study area (sandy loam developed upon gneiss bedrock), a large spatial variability of soil hydraulic properties had been reported before. The focus of the present study has been primarily the temporal variability of the soil infiltration properties. Results of a supplementary dye-tracer experiment conducted in 2005 demonstrate that in the soil studied the infiltration process is strongly dominated by preferential flow. As expected, infiltration rates varied considerably among the infiltration ring. With regard to the impact of the initial soil moisture conditions, general decrease of the infiltration rates observed on two subsequent days was detected. Surprisingly, the spatial variations between separate measuring points were vastly overridden by a huge overall increase of the infiltration rates observed throughout the years. The observed variability of the experimental data was further examined in numerical simulations of hypothetical scenarios reflecting possible variations of soil profile and experimental set-up. Axisymmetric 3D simulations were performed using S2D code. The dual-continuum model was able to describe part of the variability of infiltration curves associated with soil structure heterogeneity. None of the tested factors could explain the wide range of infiltration rate variations observed. Nevertheless, better agreement between simulated and observed infiltration characteristics could be achieved

  20. Near-surface air temperature lapse rates in Xinjiang, northwestern China

    NASA Astrophysics Data System (ADS)

    Du, Mingxia; Zhang, Mingjun; Wang, Shengjie; Zhu, Xiaofan; Che, Yanjun

    2017-01-01

    Lapse rates of near-surface (2 m) air temperature are important parameters in hydrologic and climate simulations, especially for the mountainous areas without enough in-situ observations. In Xinjiang, northwestern China, the elevations range from higher than 7000 m to lower than sea level, but the existing long-term meteorological measurements are limited and distributed unevenly. To calculate lapse rates in Xinjiang, the daily data of near-surface air temperature (T min, T ave, and T max) were measured by automatic weather stations from 2012 to 2014. All the in situ observation stations were gridded into a network of 1.5° (latitude) by 1.5° (longitude), and the spatial distribution and the daily, monthly, seasonal variations of lapse rates for T min, T ave, and T max in Xinjiang are analyzed. The Urumqi River Basin has been considered as a case to study the influence of elevation, aspect, and the wet and dry air conditions to the T min, T ave, and T max lapse rates. Results show that (1) the lapse rates for T min, T ave, and T max vary spatially during the observation period. The spatial diversity of T min lapse rates is larger than that of T ave, and that of T max is the smallest. For each season, T max lapse rates have more negative values than T ave lapse rates which are steeper than T min lapse rates. The weakest spatial diversity usually appears in July throughout a year. (2) The comparison for the three subregions (North, Middle, and South region) exhibits that lapse rates have similar day-to-day and month-to-month characteristics which present shallower values in winter months and steeper values in summer months. The T ave lapse rates in North region are shallower than those in Middle and South region, and the steepest T ave lapse rates of the three regions all appear in April. T min lapse rates are shallower than T max lapse rates. The maximum medians of T min and T max lapse rates for each grid in the three regions all appear in January, whereas the

  1. Concentrations and decay rates of ozone in indoor air in dependence on building and surface materials.

    PubMed

    Moriske, H J; Ebert, G; Konieczny, L; Menk, G; Schöndube, M

    1998-08-01

    The decay of ozone in indoor air was measured in a closed chamber after contact with different building materials and residential surfaces. The tested materials were: vinyl wall paper, woodchip paper, plywood, latex paint, fitted carpet, and plaster. In the summer of 1996, the entry of ozone from ambient air into indoor air during ventilation and the ozone decay in indoor air, after windows had been closed again, were studied. Measurements were done in a residential house on the outskirts of Berlin. The following results were gained: the chamber measurements showed a decay of ozone after contact with most of the materials put inside the chamber. Higher decay rates have been obtained for wall papers, plywood, fitted carpet and plaster. As described in the literature, ozone is able to react with olefines inside the materials and is able to form formaldehyde and other components. This formation of formaldehyde could also be confirmed in our investigations. Thus, in most cases, the formaldehyde concentrations were lower than the German guideline value of 0.1 ppm. The formation of formaldehyde could be prevented when a special wall paper that was coated with activated carbon was used. In the house, a complete ozone diffusion into indoor air took place during ventilation within 30 min. After closing the windows, the ozone concentrations decreased to the basic level before ventilation within 60-90 min.

  2. US residential building air exchange rates: new perspectives to improve decision making at vapor intrusion sites.

    PubMed

    Reichman, Rivka; Shirazi, Elham; Colliver, Donald G; Pennell, Kelly G

    2017-02-22

    Vapor intrusion (VI) is well-known to be difficult to characterize because indoor air (IA) concentrations exhibit considerable temporal and spatial variability in homes throughout impacted communities. To overcome this and other limitations, most VI science has focused on subsurface processes; however there is a need to understand the role of aboveground processes, especially building operation, in the context of VI exposure risks. This tutorial review focuses on building air exchange rates (AERs) and provides a review of literature related building AERs to inform decision making at VI sites. Commonly referenced AER values used by VI regulators and practitioners do not account for the variability in AER values that have been published in indoor air quality studies. The information presented herein highlights that seasonal differences, short-term weather conditions, home age and air conditioning status, which are well known to influence AERs, are also likely to influence IA concentrations at VI sites. Results of a 3D VI model in combination with relevant AER values reveal that IA concentrations can vary more than one order of magnitude due to air conditioning status and one order of magnitude due to house age. Collectively, the data presented strongly support the need to consider AERs when making decisions at VI sites.

  3. Smoking, air pollution, and the high rates of lung cancer in Shenyang, China

    SciTech Connect

    Xu, Z.Y.; Blot, W.J.; Xiao, H.P.; Wu, A.; Feng, Y.P.; Stone, B.J.; Sun, J.; Ershow, A.G.; Henderson, B.E.; Fraumeni, J.F. Jr. )

    1989-12-06

    A case-control study involving interviews with 1,249 patients with lung cancer and 1,345 population-based controls was conducted in Shenyang, an industrial city in northeastern China, where mortality rates are high among men and women. Cigarette smoking was found to be the principal cause of lung cancer in this population, accounting for 55% of the lung cancers in males and 37% in females. The attributable risk percentage among females is high compared to elsewhere in China, largely because of a higher prevalence of smoking among women. After adjustment for smoking, there were also significant increases in lung cancer risk associated with several measures of exposure to air pollutants. Risks were twice as high among those who reported smoky outdoor environments, and increased in proportion to years of sleeping on beds heated by coal-burning stoves (kang), and to an overall index of indoor air pollution. Threefold increases in lung cancer risk were found among men who worked in the nonferrous smelting industry, where heavy exposures to inorganic arsenic have been reported. The associations with both smoking and indoor air pollution were stronger for squamous cell and small cell carcinomas than for adenocarcinoma of the lung. Risks due to smoking or air pollution were not greatly altered by adjustment for consumption of fresh vegetables or sources of beta carotene or retinol, prior chronic lung diseases, or education level. The findings suggest that smoking and environmental pollution combine to account for the elevated rates of lung cancer mortality in Shenyang.

  4. Effect of laminar air flow and clean-room dress on contamination rates of intravenous admixtures.

    PubMed

    Brier, K L; Latiolais, C J; Schneider, P J; Moore, T D; Buesching, W J; Wentworth, B C

    1981-08-01

    The effect of laminar air flow conditions and clean-room dress on the microbial contamination rates of intravenous admixtures was investigated. Intravenous admixtures were prepared by one investigator using aseptic technique under four environmental conditions: laminar air flow conditions with clean-room dress; laminar air flow without clean-room dress; clean table top with clean-room dress; and clean table top without clean-room dress. In each environmental condition, 350 admixtures were compounded. Negative-control samples (n = 150) were also tested, as were 10 positive-control samples. Samples were tested in each of two growth media and incubated at 35 degrees C for 14 days or until growth occurred. The incidence of contamination of admixtures compounded in laminar air flow conditions was significantly less than the contamination of those compounded on a clean table top (p less than 0.05) regardless of the operator's dress. The incidence of contamination of admixtures compounded while wearing clean-room dress was not significantly different from those prepared while not wearing clean-room dress regardless of the environment in which the admixture was prepared. The overall low level of contamination [0.79% (11/1400)] was inconclusive regarding the effect of dress on the incidence of contamination when admixtures were prepared under LAF conditions. It is concluded that, when one adheres to aseptic technique, the environment in which admixtures are compounded is the most important variable affecting the microbial contamination rate.

  5. Relationship between recycling rate and air pollution: Waste management in the state of Massachusetts.

    PubMed

    Giovanis, Eleftherios

    2015-06-01

    This study examines the relationship between recycling rate of solid waste and air pollution using data from a waste municipality survey in the state of Massachusetts during the period 2009-2012. Two econometric approaches are applied. The first approach is a fixed effects model, while the second is a Stochastic Frontier Analysis (SFA) with fixed effects model. The advantage of the first approach is the ability of controlling for stable time invariant characteristics of the municipalities, thereby eliminating potentially large sources of bias. The second approach is applied in order to estimate the technical efficiency and rank of each municipality accordingly. The regressions control for various demographic, economic and recycling services, such as income per capita, population density, unemployment, trash services, Pay-as-you-throw (PAYT) program and meteorological data. The findings support that a negative relationship between particulate particles in the air 2.5 μm or less in size (PM2.5) and recycling rate is presented. In addition, the pollution is increased with increases on income per capita up to $23,000-$26,000, while after this point income contributes positively on air quality. Finally, based on the efficiency derived by the Stochastic Frontier Analysis (SFA) model, the municipalities which provide both drop off and curbside services for trash, food and yard waste and the PAYT program present better performance regarding the air quality.

  6. Effective Dose Rate Coefficients for Immersions in Radioactive Air and Water.

    PubMed

    Bellamy, M B; Veinot, K G; Hiller, M M; Dewji, S A; Eckerman, K F; Easterly, C E; Hertel, N E; Leggett, R W

    2016-05-05

    The Oak Ridge National Laboratory Center for Radiation Protection Knowledge (CRPK) has undertaken a number of calculations in support of a revision to the United States Environmental Protection Agency (US EPA) Federal Guidance Report on external exposure to radionuclides in air, water and soil (FGR 12). Age-specific mathematical phantom calculations were performed for the conditions of submersion in radioactive air and immersion in water. Dose rate coefficients were calculated for discrete photon and electron energies and folded with emissions from 1252 radionuclides using ICRP Publication 107 decay data to determine equivalent and effective dose rate coefficients. The coefficients calculated in this work compare favorably to those reported in FGR12 as well as by other authors that employed voxel phantoms for similar exposure scenarios.

  7. Mathematical Modeling of Radiocesium Migration and Air Dose Rate Changes in Eastern Fukushima Prefecture

    NASA Astrophysics Data System (ADS)

    Kitamura, A.; Sakuma, K.; Kurikami, H.; Malins, A.; Okumura, M.; Itakura, M.; Yamada, S.; Machida, M.

    2015-12-01

    Radioactive cesium that was deposited over Fukushima Prefecture after the accident at the Fukushima Daiichi nuclear power plant station is one of the major concerns regarding health physics today. Its migration is primarily by soil erosion and sediment transport within surface water during times of heavy rainfall and flooding. In order to predict the future distribution of radioactive cesium and resulting air dose rate at any location in Fukushima, we have integrated a number of mathematical models covering different time and spatial scales. In this presentation we report our overall scheme of prediction starting from sediment and radioactive cesium movement and resulting long term air dose rate changes. Specifically, we present simulation results of sediment movement and radioactive cesium migration using semi-empirical and physics based watershed models, and that of sediment and radioactive cesium behavior in a dam reservoir using one and two dimensional river simulation models. The model's results are compared with ongoing field monitoring.

  8. Effects of aluminum-copper alloy filtration on photon spectra, air kerma rate and image contrast.

    PubMed

    Gonçalves, Andréa; Rollo, João Manuel Domingos de Almeida; Gonçalves, Marcelo; Haiter Neto, Francisco; Bóscolo, Frab Norberto

    2004-01-01

    This study evaluated the performance of aluminum-copper alloy filtration, without the original aluminum filter, for dental radiography in terms of x-ray energy spectrum, air kerma rate and image quality. Comparisons of various thicknesses of aluminum-copper alloy in three different percentages were made with aluminum filtration. Tests were conducted on an intra-oral dental x-ray machine and were made on mandible phantom and on step-wedge. Depending on the thickness of aluminum-copper alloy filtration, the beam could be hardened and filtrated. The use of the aluminum-copper alloy filter resulted in reductions in air kerma rate from 8.40% to 47.33%, and indicated the same image contrast when compared to aluminum filtration. Aluminum-copper alloy filtration may be considered a good alternative to aluminum filtration.

  9. Air bubble migration rates as a proxy for bubble pressure distribution in ice cores

    NASA Astrophysics Data System (ADS)

    Dadic, Ruzica; Schneebeli, Martin; Bertler, Nancy

    2015-04-01

    Air bubble migration can be used as a proxy to measure the pressure of individual bubbles and can help constrain the gradual close-off of gas bubbles and the resulting age distribution of gases in ice cores. The close-off depth of single bubbles can vary by tens of meters, which leads to a distribution of pressures for bubbles at a given depth. The age distribution of gases (along with gas-age-ice-age differences) decreases the resolution of the gas level reconstructions from ice cores and limits our ability to determine the phase relationship between gas and ice, and thus, the impact of rapid changes of greenhouse gases on surface temperatures. For times of rapid climate change, including the last 150 years, and abrupt climate changes further back in the past, knowledge of the age distribution of the gases trapped in air bubbles will enable us to refine estimates of atmospheric changes. When a temperature gradient is applied to gas bubbles in an ice sample, the bubbles migrate toward warmer ice. This motion is caused by sublimation from the warm wall and subsequent frost deposition on the cold wall. The migration rate depends on ice temperature and bubble pressure and is proportional to the temperature gradient. The spread in migration rates for bubbles in the same samples at given temperatures should therefore reflect the variations in bubble pressures within a sample. Air bubbles with higher pressures would have been closed off higher in the firn column and thus have had time to equilibrate with the surrounding ice pressure, while air bubbles that have been closed off recently would have pressures that are similar to todays atmospheric pressure above the firn column. For ice under pressures up to ~13-16 bar, the pressure distribution of bubbles from a single depth provides a record of the trapping function of air bubbles in the firn column for a certain time in the past. We will present laboratory experiments on air bubble migration, using Antarctic ice core

  10. Determination of collisional quenching rate coefficients of metastable nitrogen molecules by air pollutants

    NASA Astrophysics Data System (ADS)

    Suzuki, Susumu; Itoh, Haruo

    2009-10-01

    It has already been investigated on the determination of the collisional quenching rate coefficients of the metastable nitrogen molecules N2(A^3σu^+ ) by some air pollutants [1] in our laboratory. In this report, we present the result on the collisional quenching rate coefficient of N2(A^3σu^+ ) by formaldehyde (CH2O) using a theoretical procedure that takes into account the reflection of metastables at the boundary. As far as we know, this report is the first result of the collisional quenching rate coefficients of N2(A^3σu^+ ) by CH2O. Formaldehyde is a colorless gas with the foul odor, and elements of the adhesive, paints, and preservative, etc. It is widely used for construction materials such as houses, because it is low cost. It is released from paint of construction materials in air, and, in that case, it is known as one of the causative agents of so-called ``Sick building syndrome'' to influence the human body harmfully even if it is a low concentration. The obtained collisional quenching rate coefficient of N2(A^3σu^+ ) by CH2O is (4.7±0.4) x 10-12 cm^3/s. Because the collisional quenching rate coefficient by CH2O is large, it is understood that CH2O receives energy easily from N2(A^3σu^+ ). In addition, we reports on the obtained collisional quenching rate coefficient of N2(A^3σu^+ ) by some air pollutants. [1] S. Suzuki, T.Suzuki and H.Itoh: Proc. of XXVIII ICPIG (Prague, Czech Republic), (2007) 1P01-40.

  11. Analysis of rainfall infiltration law in unsaturated soil slope.

    PubMed

    Zhang, Gui-rong; Qian, Ya-jun; Wang, Zhang-chun; Zhao, Bo

    2014-01-01

    In the study of unsaturated soil slope stability under rainfall infiltration, it is worth continuing to explore how much rainfall infiltrates into the slope in a rain process, and the amount of rainfall infiltrating into slope is the important factor influencing the stability. Therefore, rainfall infiltration capacity is an important issue of unsaturated seepage analysis for slope. On the basis of previous studies, rainfall infiltration law of unsaturated soil slope is analyzed. Considering the characteristics of slope and rainfall, the key factors affecting rainfall infiltration of slope, including hydraulic properties, water storage capacity (θs - θr), soil types, rainfall intensities, and antecedent and subsequent infiltration rates on unsaturated soil slope, are discussed by using theory analysis and numerical simulation technology. Based on critical factors changing, this paper presents three calculation models of rainfall infiltrability for unsaturated slope, including (1) infiltration model considering rainfall intensity; (2) effective rainfall model considering antecedent rainfall; (3) infiltration model considering comprehensive factors. Based on the technology of system response, the relationship of rainfall and infiltration is described, and the prototype of regression model of rainfall infiltration is given, in order to determine the amount of rain penetration during a rain process.

  12. Chemical response of methane/air diffusion flames to unsteady strain rate

    SciTech Connect

    Im, H.G.; Chen, J.H.; Chen, J.Y.

    1998-03-01

    Effects of unsteady strain rate on the response of methane/air diffusion flames are studied. The authors use the finite-domain opposed flow configuration in which the nozzle exit velocity is imposed as a function of time. The GRI mechanism v2.11 is used for the detailed methane/air chemistry. The response of individual species to monochromatic oscillation in strain rate with various frequencies reveals that the fluctuation of slow species, such as CO and NO{sub x}, is more rapidly suppressed as the flow time scale decreases. It is also observed that the maximum CO concentration is very insensitive to the variation in the scalar dissipation rate. An extinction event due to an abrupt imposition of high strain rates is also simulated by an impulsive velocity with various frequencies. For a fast impulse, a substantial overshoot in NO{sub 2} concentration is observed after extinction. Finally, the overall fuel burning rate shows a nonmonotonic response to the variation in characteristic unsteady time scale, while the emission indices for NO{sub x} shows monotonic decay in response as frequency is increased.

  13. Porous body infiltrating method

    DOEpatents

    Corman, Gregory Scot

    2002-01-01

    A mixture is formed that comprises at least some to about 10 wt % boron nitride and silicon. A body comprising a component that is wetted by or reacts with silicon is contacted with the mixture and the contacted body is infiltrated with silicon from the mixture.

  14. Predicting Residential Air Exchange Rates from Questionnaires and Meteorology: Model Evaluation in Central North Carolina

    PubMed Central

    2010-01-01

    A critical aspect of air pollution exposure models is the estimation of the air exchange rate (AER) of individual homes, where people spend most of their time. The AER, which is the airflow into and out of a building, is a primary mechanism for entry of outdoor air pollutants and removal of indoor source emissions. The mechanistic Lawrence Berkeley Laboratory (LBL) AER model was linked to a leakage area model to predict AER from questionnaires and meteorology. The LBL model was also extended to include natural ventilation (LBLX). Using literature-reported parameter values, AER predictions from LBL and LBLX models were compared to data from 642 daily AER measurements across 31 detached homes in central North Carolina, with corresponding questionnaires and meteorological observations. Data was collected on seven consecutive days during each of four consecutive seasons. For the individual model-predicted and measured AER, the median absolute difference was 43% (0.17 h−1) and 40% (0.17 h−1) for the LBL and LBLX models, respectively. Additionally, a literature-reported empirical scale factor (SF) AER model was evaluated, which showed a median absolute difference of 50% (0.25 h−1). The capability of the LBL, LBLX, and SF models could help reduce the AER uncertainty in air pollution exposure models used to develop exposure metrics for health studies. PMID:21069949

  15. Air exchange rates and migration of VOCs in basements and residences

    PubMed Central

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Rowe, Zachary; Chin, Jo-Yu

    2015-01-01

    Basements can influence indoor air quality by affecting air exchange rates (AERs) and by the presence of emission sources of volatile organic compounds (VOCs) and other pollutants. We characterized VOC levels, AERs and interzonal flows between basements and occupied spaces in 74 residences in Detroit, Michigan. Flows were measured using a steady-state multi-tracer system, and 7-day VOC measurements were collected using passive samplers in both living areas and basements. A walkthrough survey/inspection was conducted in each residence. AERs in residences and basements averaged 0.51 and 1.52 h−1, respectively, and had strong and opposite seasonal trends, e.g., AERs were highest in residences during the summer, and highest in basements during the winter. Air flows from basements to occupied spaces also varied seasonally. VOC concentration distributions were right-skewed, e.g., 90th percentile benzene, toluene, naphthalene and limonene concentrations were 4.0, 19.1, 20.3 and 51.0 μg m−3, respectively; maximum concentrations were 54, 888, 1117 and 134 μg m−3. Identified VOC sources in basements included solvents, household cleaners, air fresheners, smoking, and gasoline-powered equipment. The number and type of potential VOC sources found in basements are significant and problematic, and may warrant advisories regarding the storage and use of potentially strong VOCs sources in basements. PMID:25601281

  16. Predicting residential air exchange rates from questionnaires and meteorology: model evaluation in central North Carolina.

    PubMed

    Breen, Michael S; Breen, Miyuki; Williams, Ronald W; Schultz, Bradley D

    2010-12-15

    A critical aspect of air pollution exposure models is the estimation of the air exchange rate (AER) of individual homes, where people spend most of their time. The AER, which is the airflow into and out of a building, is a primary mechanism for entry of outdoor air pollutants and removal of indoor source emissions. The mechanistic Lawrence Berkeley Laboratory (LBL) AER model was linked to a leakage area model to predict AER from questionnaires and meteorology. The LBL model was also extended to include natural ventilation (LBLX). Using literature-reported parameter values, AER predictions from LBL and LBLX models were compared to data from 642 daily AER measurements across 31 detached homes in central North Carolina, with corresponding questionnaires and meteorological observations. Data was collected on seven consecutive days during each of four consecutive seasons. For the individual model-predicted and measured AER, the median absolute difference was 43% (0.17 h(-1)) and 40% (0.17 h(-1)) for the LBL and LBLX models, respectively. Additionally, a literature-reported empirical scale factor (SF) AER model was evaluated, which showed a median absolute difference of 50% (0.25 h(-1)). The capability of the LBL, LBLX, and SF models could help reduce the AER uncertainty in air pollution exposure models used to develop exposure metrics for health studies.

  17. Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

    PubMed

    Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

    2008-11-01

    A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates.

  18. Infiltration of outdoor ultrafine particles into a test house.

    PubMed

    Rim, Donghyun; Wallace, Lance; Persily, Andrew

    2010-08-01

    Ultrafine particles (UFP) (<100 nm) have been related to adverse human health effects such as oxidative stress and cardiovascular mortality. However, human exposure to particles of outdoor origin is heavily dependent on their infiltration into homes. The infiltration factor (Finf) and its variation as a function of several factors becomes of enormous importance in epidemiological studies. The objective of this study is to investigate the transport of UFP into a residential building and to determine the functional dependence of infiltration on particle size and air change rate. A secondary objective was to estimate the values of the penetration coefficient P and composite deposition rate kcomp that enter into the definition of Finf. Using continuous measurements of indoor and outdoor concentrations of size-resolved particles ranging from 5 to 100 nm in a manufactured test house, particle penetration through the building, composite deposition, and the resulting value of Finf were calculated for two cases: closed windows and one window open 7.5 cm. Finf ranged from close to 0 (particles<10 nm) to 0.3 (particles>80 nm) with windows closed and from 0 to 0.6 with one window open. The penetration coefficient (closed windows) increased from about 0.2 for 10-nm particles to an asymptote near 0.6 for particles from 30-100 nm. Open window penetration coefficients were higher, ranging from 0.6 to 0.8. Closed-window composite deposition rates, which included losses to the furnace filter and to the ductwork as well as to interior surfaces, monotonically decreased from levels of about 1.5 h(-1) for 10-nm particles to 0.3 h(-1) for 100-nm particles. For the open-window case, composite deposition rates were higher for particles<20 nm, reaching values of 3.5 h(-1). Mean standard errors associated with estimates of P, kcomp, and Finf for two series of measurements ranged from 1.0% to 4.4%.

  19. Modified perfluorocarbon tracer method for measuring effective multizone air exchange rates.

    PubMed

    Shinohara, Naohide; Kataoka, Toshiyuki; Takamine, Koichi; Butsugan, Michio; Nishijima, Hirokazu; Gamo, Masashi

    2010-09-01

    A modified procedure was developed for the measurement of the effective air exchange rate, which represents the relationship between the pollutants emitted from indoor sources and the residents' level of exposure, by placing the dosers of tracer gas at locations that resemble indoor emission sources. To measure the 24-h-average effective air exchange rates in future surveys based on this procedure, a low-cost, easy-to-use perfluorocarbon tracer (PFT) doser with a stable dosing rate was developed by using double glass vials, a needle, a polyethylene-sintered filter, and a diffusion tube. Carbon molecular sieve cartridges and carbon disulfide (CS₂) were used for passive sampling and extraction of the tracer gas, respectively. Recovery efficiencies, sampling rates, and lower detection limits for 24-h sampling of hexafluorobenzene, octafluorotoluene, and perfluoroallylbenzene were 40% ± 3%, 72% ± 5%, and 84% ± 6%; 10.5 ± 1.1, 14.4 ± 1.4, and 12.2 ± 0.49 mL min⁻¹; and 0.20, 0.17, and 0.26 μg m⁻³, respectively.

  20. Effect of outside air ventilation rate on volatile organic compound concentrations in a call center

    NASA Astrophysics Data System (ADS)

    Hodgson, A. T.; Faulkner, D.; Sullivan, D. P.; DiBartolomeo, D. L.; Russell, M. L.; Fisk, W. J.

    A study of the relationship between outside air ventilation rate and concentrations of volatile organic compounds (VOCs) generated indoors was conducted in a call center office building. The building, with two floors and a total floor area of 4600 m 2, is located in the San Francisco Bay Area, CA. Ventilation rates were manipulated with the building's four air handling units (AHUs). VOC and CO 2 concentrations in the AHU returns were measured on 7 days during a 13-week period. VOC emission factors were determined for individual zones on days when they were operating at near steady-state conditions. The emission factor data were subjected to principal component (PC) analysis to identify groups of co-varying compounds. Potential sources of the PC vectors were ascribed based on information from the literature. The per occupant CO 2 generation rates were 0.0068-0.0092 l s -1. The per occupant isoprene generation rates of 0.2-0.3 mg h -1 were consistent with the value predicted by mass balance from breath concentration and exhalation rate. The relationships between indoor minus outdoor VOC concentrations and ventilation rate were qualitatively examined for eight VOCs. Of these, acetaldehyde and hexanal, which likely were associated with material sources, and decamethylcyclopentasiloxane, associated with personal care products, exhibited general trends of higher concentrations at lower ventilation rates. For other compounds, a clear inverse relationship between VOC concentrations and ventilation was not observed. The net concentration of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate isomers, examples of low-volatility compounds, changed very little with ventilation likely due to sorption and re-emission effects. These results illustrate that the efficacy of ventilation for controlling VOC concentrations can vary considerably depending upon the operation of the building, the pollutant sources and the physical and chemical processes affecting the pollutants. Thus, source

  1. Infiltration and instability in dune erosion

    NASA Astrophysics Data System (ADS)

    Palmsten, Margaret L.; Holman, Robert A.

    2011-10-01

    Forecasting dune erosion prior to a storm or over longer periods requires knowledge of the fluid forces on the dune sediments. To improve our predictive capability for this process, we propose a new model in which dune slumping occurs when water, which infiltrates horizontally into the dune, increases the overburden sufficiently to destabilize the dune. Horizontal infiltration is driven by suction of water from swash into the dune via capillary action and is a surprisingly strong process with rapid time scales. Because the elevated pore water concentrations increase the apparent cohesion of the wetted sediments, we also propose that the entire volume of wetted sand slumps as a unit when the dune becomes unstable and erosion can be modeled based on the force balance on a sliding block. Several versions of this model were tested, including a numerical infiltration model, a simplified infiltration equation, and an equation based on offshore wave forcing, rather than known forcing at the dune. The model was tested using data from a large-scale laboratory experiment with a storm hydrograph to investigate the time dependence of dune erosion. Predicting slope stability using a numerical infiltration model with known forcing explained 72% of the observed variance in erosion rate, while a simplified stability and infiltration model explained 58%. Error statistics suggest that we captured the majority of the physics controlling dune erosion in this laboratory experiment and that the simplified model will be useful as a forecasting tool.

  2. Relationship of air sampling rates of semipermeable membrane devices with the properties of organochlorine pesticides.

    PubMed

    Zhu, Xiuhua; Ding, Guanghui; Levy, Walkiria; Jakobi, Gert; Schramm, Karl-Werner

    2011-06-01

    The organochlorine pesticides (OCP) in Eastern-Barvaria at Haidel 1160 m a.s.l. were monitored with a low volume active air sampler and semi-permeable membrane devices (SPMD). The air sampling rates (Rair) of SPMD for OCP were calculated. Quantitative structure-property relationship (QSPR) models of Rair of SPMD were developed for OCP with partial least square (PLS) regression. Quantum chemical descriptors computed by semi-empirical PM6 method were used as predictor variables. The cumulative variance of the dependent variable explained by the PLS components and determined by cross-validation (Q(2)cum), for the optimal models, is 0.637, indicating that the model has good predictive ability and robustness, and could be used to estimate Rair values of OCP. The main factors governing Rair of OCP are intermolecular interactions and the energy required for cave-forming in dissolution of OCP into triolein of SPMD.

  3. Resin infiltration transfer technique

    DOEpatents

    Miller, David V.; Baranwal, Rita

    2009-12-08

    A process has been developed for fabricating composite structures using either reaction forming or polymer infiltration and pyrolysis techniques to densify the composite matrix. The matrix and reinforcement materials of choice can include, but are not limited to, silicon carbide (SiC) and zirconium carbide (ZrC). The novel process can be used to fabricate complex, net-shape or near-net shape, high-quality ceramic composites with a crack-free matrix.

  4. Joint modeling of canopy interception and soil water flow to compare infiltration rates below two land covers (Galápagos Islands)

    NASA Astrophysics Data System (ADS)

    Dominguez, C.; Pryet, A.; Gonzalez, A.; Tournebize, J.; Chaumont, C.; Villacis, M.; D'ozouville, N. I.; Violette, S.

    2014-12-01

    Most volcanic islands face issues due to an imbalance between constantly increasing population and limited freshwater resources. In this context, groundwater exploitation is a valuable strategy and the estimation of recharge rates is crucial for water management planning, specially considering the changes in land use. In the present study we aim to assess the impact of land cover change on the groundwater recharge at the Santa Cruz Island (Galápagos), where a marked vegetation zonation is observed on the windward side. We studied during one year two adjacent land covers that extend on the majority of the island: a secondary forest and a pasture land. We monitored the climatic variables and throughfall over the pasture and under the forest, respectively. At both plots, the soil water suction was measured with automatic tensiometers in a vertical profile at different soil depth. We associate (i) a Rutter-type canopy interception model, with (ii) a 1-D physically-based variably saturated flow model. This allows the estimation of interception losses, cloud water interception, plant transpiration, runoff and deep percolation. The model was calibrated with the throughfall and soil water suction measurements. The model reveals contrasting behaviors in the soil water transfers between the two plots. The difference could be attributed to the reduction of the net precipitation input at the forest, which is caused by higher evaporation losses at the canopy. The approach provides insights about the soil water dynamics under different land covers, and may help to assess the effect of land use change in the groundwater recharge of a vast region of the island.

  5. Fabrication of fiber-reinforced composites by chemical vapor infiltration

    SciTech Connect

    Matlin, W.M.; Stinton, D.P.; Besmann, T.M.

    1995-08-01

    A two-step forced chemical vapor infiltration process was developed that reduced infiltration times for 4.45 cm dia. by 1.27 cm thick Nicalon{sup +} fiber preforms by two thirds while maintaining final densities near 90 %. In the first stage of the process, micro-voids within fiber bundles in the cloth were uniformly infiltrated throughout the preform. In the second stage, the deposition rate was increased to more rapidly fill the macro-voids between bundles within the cloth and between layers of cloth. By varying the thermal gradient across the preform uniform infiltration rates were maintained and high final densities achieved.

  6. Numerical analysis of a neutron radiography-monitored infiltration experiment: Two-phase modeling using TOUGH2

    NASA Astrophysics Data System (ADS)

    Princ, Tomas; Sacha, Jan; Snehota, Michal

    2015-04-01

    It has been shown in ponded infiltration-outflow column experiments that true steady state flow is often not reached in certain soils exhibiting preferential flow. Experiments often show a temporal change of flow rate that can, in the case of experiments conducted on saturated samples at constant head gradients, be interpreted as variations of saturated hydraulic conductivity. It has also been shown that these variations can be caused by slow redistribution of entrapped air in the sample. The experiment presented in this study was conducted on a small fabricated sample with axially symmetrical inner geometry of material distribution. In preparing the sample, areas of fine sand were surrounded by continuous preferential pathways composed of coarse sand. Ponded infiltration was performed on the sample while monitoring using neutron imaging was conducted to obtain spatiotemporal information about the water content distribution in the sample. Results of the experiment revealed that during the quasi-steady state stage of the experiment the saturated hydraulic conductivity gradually decreased due to the transfer of air bubbles from fine sand to coarse sand. Flow through the coarse sand became partially blocked by air bubbles and the overall quasi-steady flow rate consequently decreased by 30% during six hours of infiltration. In an attempt to model this behavior, we simulated ponded infiltration in two dimensional (2D) domains using the EOS3 module of the numerical simulator TOUGH2 (Lawrence Berkeley National Laboratory). The main objective was to determine which types of preferential pathway patterns were prone to air entrapment and whether the air redistribution observed in the experiment could be numerically simulated. Modeling was conducted in three different 2D domains with increasing complexity of the preferential pathways' geometry. Analysis of the results confirmed that during ponded infiltration, water percolated fastest at the start of infiltration through the

  7. [Characteristics of water infiltration in urban soils of Nanjing City].

    PubMed

    Yang, Jin-Ling; Zhang, Gan-Lin; Yuan, Da-Gang

    2008-02-01

    By using dual-ring method, this paper measured the water infiltration rate in urban soils under representative land use patterns in Nanjing City, and studied the characteristics of water infiltration in the soils with different compaction degree. The results showed that there was a great difference in the infiltration rate among the soils with different compactness. Soil infiltration rate decreased with increasing bulk density and decreasing porosity, and the water-transport-limiting layer existed in heavily compacted soils resulted in a dramatic decrease of final stabilized infiltration rate. There was a significant linear relationship between the initial and final infiltration rates in the same soil though their absolute values had a great difference. The urban soils in Nanjing City had a wide range of final infiltration rate varied from 1 mm X h(-1) to 679 mm X h(-1), which was highly related to the soil compactness, structural status, and skeleton grain contents. The decrease of urban soil infiltration rate could induce the increase of runoff and of the probability and intensity of flooding.

  8. Estimating the Limits of Infiltration in the Urban Appalachian Plateau

    NASA Astrophysics Data System (ADS)

    Lavin, S. M.; Bain, D.; Hopkins, K. G.; Pfeil-McCullough, E. K.; Copeland, E.

    2014-12-01

    Green infrastructure in urbanized areas commonly uses infiltration systems, such as rain gardens, swales and trenches, to convey surface runoff from impervious surfaces into surrounding soils. However, precipitation inputs can exceed soil infiltration rates, creating a limit to infiltration-based storm water management, particularly in urban areas covered by impervious surfaces. Given the limited availability and varied quality of soil infiltration rate data, we synthesized information from national databases, available field test data, and applicable literature to characterize soil infiltration rate distributions, focusing on Allegheny County, Pennsylvania as a case study. A range of impervious cover conditions was defined by sampling available GIS data (e.g., LiDAR and street edge lines) with analysis windows placed randomly across urbanization gradients. Changes in effective precipitation caused by impervious cover were calculated across these gradients and compared to infiltration rate distributions to identify thresholds in impervious coverage where these limits are exceeded. Many studies have demonstrated the effects of urbanization on infiltration, but the identification of these thresholds will clarify interactions between impervious cover and soil infiltration. These methods can help identify sections of urban areas that require augmentation of infiltration-based systems with additional infrastructural strategies, especially as green infrastructure moves beyond low impact development towards more frequent application during infilling of existing urban systems.

  9. Measurement of air exchange rates in different indoor environments using continuous CO2 sensors.

    PubMed

    You, Yan; Niu, Can; Zhou, Jian; Liu, Yating; Bai, Zhipeng; Zhang, Jiefeng; He, Fei; Zhang, Nan

    2012-01-01

    A new air exchange rate (AER) monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m3 environmental chamber at different AERs (0.1-10.0 hr(-1)). AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity (RH), and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved: duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr(-1) in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr(-1) in fall, and 0.12 to 1.39 hr(-1) in winter with a median AER of 1.15.

  10. Measuring and modeling air exchange rates inside taxi cabs in Los Angeles, California

    NASA Astrophysics Data System (ADS)

    Shu, Shi; Yu, Nu; Wang, Yueyan; Zhu, Yifang

    2015-12-01

    Air exchange rates (AERs) have a direct impact on traffic-related air pollutant (TRAP) levels inside vehicles. Taxi drivers are occupationally exposed to TRAP on a daily basis, yet there is limited measurement of AERs in taxi cabs. To fill this gap, AERs were quantified in 22 representative Los Angeles taxi cabs including 10 Prius, 5 Crown Victoria, 3 Camry, 3 Caravan, and 1 Uplander under realistic driving (RD) conditions. To further study the impacts of window position and ventilation settings on taxi AERs, additional tests were conducted on 14 taxis with windows closed (WC) and on the other 8 taxis with not only windows closed but also medium fan speed (WC-MFS) under outdoor air mode. Under RD conditions, the AERs in all 22 cabs had a mean of 63 h-1 with a median of 38 h-1. Similar AERs were observed under WC condition when compared to those measured under RD condition. Under WC-MFS condition, AERs were significantly increased in all taxi cabs, when compared with those measured under RD condition. A General Estimating Equation (GEE) model was developed and the modeling results showed that vehicle model was a significant factor in determining the AERs in taxi cabs under RD condition. Driving speed and car age were positively associated with AERs but not statistically significant. Overall, AERs measured in taxi cabs were much higher than typical AERs people usually encounter in indoor environments such as homes, offices, and even regular passenger vehicles.

  11. Spatial analysis of water infiltration in urban soils. Case study of Iasi municipality (Romania)

    NASA Astrophysics Data System (ADS)

    Cristian Vasilica, Secu; Ionut, Minea

    2013-04-01

    The post-communist period (after 1989) caused important changes in the functional structure of Iasi municipality. The partly dismantling of the industrial area, the urban sprawl against the periurban and agricultural space, the new infrastructure works, all these determined important changes of soils' physical and morphological properties (e.g. porosity, density, compaction, infiltration rate etc., in the first case, and changes in soil horizons, in the second case etc.). This study aims to prove the variability of physical properties through the combination of statistical and geostatistical methods intended for a correct spatial representation. Water infiltration in urban soils was analyzed in relation to land use and the age of parental materials. Field investigations consisted in measurements of the water infiltration (by the means of Turf Tech infiltrometer), resistance to penetration (penetrologger), moisture deficit (Theta Probe) and resistivity (EC) for 70 equally distanced points (750 m x 750 m) placed in a grid covering more than 33 km2. In the laboratory, there were determined several parameters as density, porosity (air pycnometer), gravimetric moisture and other hydrophysical indicators. Filed investigations results are very heterogeneous, because of the human intervention on soils. The curves of variation for the rate water infiltration in soils indicate a downward trend, from high values in first time interval (one minute), between 5000 and 60 mm/h-1, gradually decreasing to the interval of 5-10 minutes (between 30 and 1000 mm/ h-1 to a general trend of flattening after a large time interval (in the timeframe of 50-60 minutes, the infiltration rate ranges between 4 and 142 mm•h-1). The highest frequency (≥65%) caracterizes the infiltration rates between 20 and 65 mm•h-1. For each analyzed sector (residential areas, industrial areas, degraded lands, recreational areas - parks and botanical gardens, forests heterogeneous agricultural lands), the

  12. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    PubMed

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions.

  13. Air-Supported Anti-Infiltration Barrier.

    DTIC Science & Technology

    1966-08-01

    traff isuon tho r ation its cant in an nanner an u thorix orson i rohibito by low. EX OMf E DOWNGRADDTOROM CNFIDENTIL TO U0C -IN ACCORDANCE WJWH...Murray Kamrass and Dr. W. Scott Payne, of IDA/RESD, for gathering much of the background information on costs and sortie capability that made these

  14. Measurement of Ozone Emission and Particle Removal Rates from Portable Air Purifiers

    ERIC Educational Resources Information Center

    Mang, Stephen A.; Walser, Maggie L.; Nizkorodov, Sergey A.; Laux, John M.

    2009-01-01

    Portable air purifiers are popular consumer items, especially in areas with poor air quality. Unfortunately, most users of these air purifiers have minimal understanding of the factors affecting their efficiency in typical indoor settings. Emission of the air pollutant ozone (O[subscript 3]) by certain air purifiers is of particular concern. In an…

  15. A hydrologic analysis for the infiltration basins planned on Jeju Island, Korea

    NASA Astrophysics Data System (ADS)

    Lee, S.; Kang, T.; Lee, J.; Kang, S.

    2010-12-01

    Urban development is a cause of expansion of impervious area. It reduces infiltration of rain water and may increase runoff volume from storms. Infiltration basins can be a method to receive storm water and to let the water move into the soil. The contents of the study include a hydrologic analysis on a site and an evaluation of the capacity of infiltration basins planned on the site. Most region of Jeju Island, Korea is highly pervious. Three infiltration basins were designed on the area of the Jeju English Education City. To evaluate adequacy of the capacities of the infiltration basins, infiltration rates were measured and storm water runoff was simulated. Infiltration rates on the surface of the reserved land for infiltration basins were measured by a standard double ring infiltrometer or a small infiltrometer. A FORTRAN version of SWMM was modified to incorporate the infiltration basin and the basic equations of the infiltration basin are same as those of the infiltration trench used in MIDUSS. The code modified was used to simulate storm runoff from watersheds, infiltration from the infiltration basins, and reservoir routing of the infiltration basins. The saturated hydraulic conductivities on the reserved sites were measured by 0.0068, 0.0038, and 0.00017 cm/sec. The return period of the design rainfall is fifty years. The following results were obtained from a hydrologic analysis on the watersheds and the infiltration basins to be built. The two infiltration basins with higher infiltration rates have adequate capacities to infiltrate the total water inflow to the basins. Some water, however releases from the other infiltration basin and the capacity of the basin is not sufficient to infiltrate the total runoff after the land use change. A channel is needed in which the water released from the less pervious basin flows. The hydrologic analysis method of the study can be used for capacity evaluation of future infiltration basins on highly pervious areas in

  16. Evaluation of an Infiltration Model with Microchannels

    NASA Astrophysics Data System (ADS)

    Garcia-Serrana, M.; Gulliver, J. S.; Nieber, J. L.

    2015-12-01

    This research goal is to develop and demonstrate the means by which roadside drainage ditches and filter strips can be assigned the appropriate volume reduction credits by infiltration. These vegetated surfaces convey stormwater, infiltrate runoff, and filter and/or settle solids, and are often placed along roads and other impermeable surfaces. Infiltration rates are typically calculated by assuming that water flows as sheet flow over the slope. However, for most intensities water flow occurs in narrow and shallow micro-channels and concentrates in depressions. This channelization reduces the fraction of the soil surface covered with the water coming from the road. The non-uniform distribution of water along a hillslope directly affects infiltration. First, laboratory and field experiments have been conducted to characterize the spatial pattern of flow for stormwater runoff entering onto the surface of a sloped surface in a drainage ditch. In the laboratory experiments different micro-topographies were tested over bare sandy loam soil: a smooth surface, and three and five parallel rills. All the surfaces experienced erosion; the initially smooth surface developed a system of channels over time that increased runoff generation. On average, the initially smooth surfaces infiltrated 10% more volume than the initially rilled surfaces. The field experiments were performed in the side slope of established roadside drainage ditches. Three rates of runoff from a road surface into the swale slope were tested, representing runoff from 1, 2, and 10-year storm events. The average percentage of input runoff water infiltrated in the 32 experiments was 67%, with a 21% standard deviation. Multiple measurements of saturated hydraulic conductivity were conducted to account for its spatial variability. Second, a rate-based coupled infiltration and overland model has been designed that calculates stormwater infiltration efficiency of swales. The Green-Ampt-Mein-Larson assumptions were

  17. Sequestration of Sr-90 Subsurface Contamination in the Hanford 100-N Area by Surface Infiltration of a Ca-Citrate-Phosphate Solution

    SciTech Connect

    Szecsody, James E.; Rockhold, Mark L.; Oostrom, Martinus; Moore, R. C.; Burns, Carolyn A.; Williams, Mark D.; Zhong, Lirong; Fruchter, Jonathan S.; McKinley, James P.; Vermeul, Vincent R.; Covert, Matthew A.; Wietsma, Thomas W.; Breshears, Andrew T.; Garcia, Ben J.

    2009-03-01

    The objective of this project is to develop a method to emplace apatite precipitate in the 100N vadose zone, which results in sorption and ultimately incorporation of Sr-90 into the apatite structure. The Ca-citrate-PO4 solution can be infiltrated into unsaturated sediments to result in apatite precipitate to provide effective treatment of Sr-90 contamination. Microbial redistribution during solution infiltration and a high rate of citrate biodegradation for river water microbes (water used for solution infiltration) results in a relatively even spatial distribution of the citrate biodegradation rate and ultimately apatite precipitate in the sediment. Manipulation of the Ca-citrate-PO4 solution infiltration strategy can be used to result in apatite precipitate in the lower half of the vadose zone (where most of the Sr-90 is located) and within low-K layers (which are hypothesized to have higher Sr-90 concentrations). The most effective infiltration strategy to precipitate apatite at depth (and with sufficient lateral spread) was to infiltrate a high concentration solution (6 mM Ca, 15 mM citrate, 60 mM PO4) at a rapid rate (near ponded conditions), followed by rapid, then slow water infiltration. Repeated infiltration events, with sufficient time between events to allow water drainage in the sediment profile can be used to buildup the mass of apatite precipitate at greater depth. Low-K heterogeneities were effectively treated, as the higher residual water content maintained in these zones resulted in higher apatite precipitate concentration. High-K zones did not receive sufficient treatment by infiltration, although an alternative strategy of air/surfactant (foam) was demonstrated effective for targeting high-K zones. The flow rate manipulation used in this study to treat specific depths and heterogeneities are not as easy to implement at field scale due to the lack of characterization of heterogeneities and difficulty tracking the wetting front over a large

  18. Modeling residential fine particulate matter infiltration for exposure assessment.

    PubMed

    Hystad, Perry U; Setton, Eleanor M; Allen, Ryan W; Keller, Peter C; Brauer, Michael

    2009-09-01

    Individuals spend the majority of their time indoors; therefore, estimating infiltration of outdoor-generated fine particulate matter (PM(2.5)) can help reduce exposure misclassification in epidemiological studies. As indoor measurements in individual homes are not feasible in large epidemiological studies, we evaluated the potential of using readily available data to predict infiltration of ambient PM(2.5) into residences. Indoor and outdoor light scattering measurements were collected for 84 homes in Seattle, Washington, USA, and Victoria, British Columbia, Canada, to estimate residential infiltration efficiencies. Meteorological variables and spatial property assessment data (SPAD), containing detailed housing characteristics for individual residences, were compiled for both study areas using a geographic information system. Multiple linear regression was used to construct models of infiltration based on these data. Heating (October to February) and non-heating (March to September) season accounted for 36% of the yearly variation in detached residential infiltration. Two SPAD housing characteristic variables, low building value, and heating with forced air, predicted 37% of the variation found between detached residential infiltration during the heating season. The final model, incorporating temperature and the two SPAD housing characteristic variables, with a seasonal interaction term, explained 54% of detached residential infiltration. Residences with low building values had higher infiltration efficiencies than other residences, which could lead to greater exposure gradients between low and high socioeconomic status individuals than previously identified using only ambient PM(2.5) concentrations. This modeling approach holds promise for incorporating infiltration efficiencies into large epidemiology studies, thereby reducing exposure misclassification.

  19. Temperature lapse rates at restricted thermodynamic equilibrium. Part II: Saturated air and further discussions

    NASA Astrophysics Data System (ADS)

    Björnbom, Pehr

    2016-03-01

    In the first part of this work equilibrium temperature profiles in fluid columns with ideal gas or ideal liquid were obtained by numerically minimizing the column energy at constant entropy, equivalent to maximizing column entropy at constant energy. A minimum in internal plus potential energy for an isothermal temperature profile was obtained in line with Gibbs' classical equilibrium criterion. However, a minimum in internal energy alone for adiabatic temperature profiles was also obtained. This led to a hypothesis that the adiabatic lapse rate corresponds to a restricted equilibrium state, a type of state in fact discussed already by Gibbs. In this paper similar numerical results for a fluid column with saturated air suggest that also the saturated adiabatic lapse rate corresponds to a restricted equilibrium state. The proposed hypothesis is further discussed and amended based on the previous and the present numerical results and a theoretical analysis based on Gibbs' equilibrium theory.

  20. Measurement of nonlinear refractive index and ionization rates in air using a wavefront sensor.

    PubMed

    Schwarz, Jens; Rambo, Patrick; Kimmel, Mark; Atherton, Briggs

    2012-04-09

    A wavefront sensor has been used to measure the Kerr nonlinear focal shift of a high intensity ultrashort pulse beam in a focusing beam geometry while accounting for the effects of plasma-defocusing. It is shown that plasma-defocusing plays a major role in the nonlinear focusing dynamics and that measurements of Kerr nonlinearity and ionization are coupled. Furthermore, this coupled effect leads to a novel way that measures the laser ionization rates in air under atmospheric conditions as well as Kerr nonlinearity. The measured nonlinear index n₂ compares well with values found in the literature and the measured ionization rates could be successfully benchmarked to the model developed by Perelomov, Popov, and Terentev (PPT model) [Sov. Phys. JETP 50, 1393 (1966)].

  1. Catchment-scale distribution of radiocesium air dose rate in a mountainous deciduous forest and its relation to topography.

    PubMed

    Atarashi-Andoh, Mariko; Koarashi, Jun; Takeuchi, Erina; Tsuduki, Katsunori; Nishimura, Syusaku; Matsunaga, Takeshi

    2015-09-01

    A large number of air dose rate measurements were collected by walking through a mountainous area with a small gamma-ray survey system, KURAMA-II. The data were used to map the air dose rate of a mountainous deciduous forest that received radiocesium from the Fukushima Dai-ichi Nuclear Power Plant accident. Measurements were conducted in a small stream catchment (0.6 km(2) in area) in August and September 2013, and the relationship between air dose rates and the mountainous topography was examined. Air dose rates increased with elevation, indicating that more radiocesium was deposited on ridges, and suggesting that it had remained there for 2.5 y with no significant downslope migration by soil erosion or water drainage. Orientation in relation to the dominant winds when the radioactive plume flowed to the catchment also strongly affected the air dose rates. Based on our continuous measurements using the KURAMA-II, we describe the variation in air dose rates in a mountainous forest area and suggest that it is important to consider topography when determining sampling points and resolution to assess the spatial variability of dose rates and contaminant deposition.

  2. Effect of air pollutants on the photosynthetic and dark respiration rates of Phaseolus vulgaris

    SciTech Connect

    Borgman, L.M.

    1982-01-01

    The effects of continuous fumigations with pollutant gases on net and gross photosynthesis, dark respiration, respiration/gross photosynthesis ratios, root/shoot ratios, and chloroplast ultrastructure were examined. Plants of Phaseolus vulgaris L. Blue Lakes, were grown in paired plexi-glass chambers. Photosynthetic and respiration rates of 12-19 day-old plants were measured by infrared gas analysis. The plants were dried and root/shoot ratios calculated. A significant increase (28.9%) in gross photosynthesis of plants exposed to 10 ppm. CO was evident compared to the controls. Although net photosynthesis was not significantly affected by 0.035-0.04 ppm NO/sub 2/, gross photosynthesis, dark respiration, and R/G were significantly greater than in controls. Concentrations of 0.04-0.005 SO/sub 2/ resulted in significantly greater respiration and R/G ratios. This procedure resulted in significantly reduced net and gross photosynthetic rates. Ozone exposures of 10-20 ppm for eight hours a day, five days a week, resulted in progressively lower net and gross photosynthetic rates as the week progressed and R/G ratios were significantly higher. Ozone exposures of 6-8 ppm reduced net and gross photosynthetic rates significantly. Average root/shoot ratios of all exposed plants were significantly greater (14.8%) than those grown in pollutant-free air. The concentrations employed were comparable to the federal air pollution standards. It was concluded that these low levels of pollutant gases are capable of altering physiological activities which may result in reduced yield.

  3. Eosinophilic Liver Infiltration

    PubMed Central

    Figueroa Rivera, Ivonne; Toro, Doris H.; Gutierrez, Jose; Acosta, Eduardo

    2015-01-01

    Eosinophilic liver infiltration is a commonly encountered focal eosinophil-related inflammation with or without necrosis, which can be seen on computed tomography (CT) in the presence of peripheral eosinophilia. Although this entity has a relatively benign course, it is related to numerable conditions for which diagnosis may be challenging and requires substantial diagnostic work-up for proper management and care of the underlying disease. We report a case of a 60-year-old man who presented with a 1-week history of right upper quadrant abdominal pain with multiple ill-defined liver hypodensities associated with significant eosinophilia. PMID:26504883

  4. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1991-01-01

    Progress was made on the preparation of carbon fiber composites using advanced polymer resins. Processes reported include powder towpreg process, weaving towpreg made from dry powder prepreg, composite from powder coated towpreg, and toughening of polyimide resin (PMR) composites by semi-interpenetrating networks. Several important areas of polymer infiltration into fiber bundles will be researched. Preparation to towpreg for textile preform weaving and braiding and for automated tow placement is a major goal, as are the continued development of prepregging technology and the various aspects of composite part fabrication.

  5. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1995-01-01

    Polymer infiltration investigations were directed toward development of methods by which to produce advanced composite material for automated part fabrication utilizing textile and robotic technology in the manufacture of subsonic and supersonic aircraft. Significant progress was made during the project on the preparation of carbon fiber composites using advanced polymer resins. The findings and results of the project are summarized in the attached paper entitled 'Powder-Coated Towpreg: Avenues to Near Net Shape Fabrication of High Performance Composite.' Also attached to this report is the second of two patent applications submitted as a result of these studies.

  6. Temperature and strain rate effects in high strength high conductivity copper alloys tested in air

    SciTech Connect

    Edwards, D.J.

    1998-03-01

    The tensile properties of the three candidate alloys GlidCop{trademark} Al25, CuCrZr, and CuNiBe are known to be sensitive to the testing conditions such as strain rate and test temperature. This study was conducted on GlidCop Al25 (2 conditions) and Hycon 3HP (3 conditions) to ascertain the effect of test temperature and strain rate when tested in open air. The results show that the yield strength and elongation of the GlidCop Al25 alloys exhibit a strain rate dependence that increases with temperature. Both the GlidCop and the Hycon 3 HP exhibited an increase in strength as the strain rate increased, but the GlidCop alloys proved to be the most strain rate sensitive. The GlidCop failed in a ductile manner irrespective of the test conditions, however, their strength and uniform elongation decreased with increasing test temperature and the uniform elongation also decreased dramatically at the lower strain rates. The Hycon 3 HP alloys proved to be extremely sensitive to test temperature, rapidly losing their strength and ductility when the temperature increased above 250 C. As the test temperature increased and the strain rate decreased the fracture mode shifted from a ductile transgranular failure to a ductile intergranular failure with very localized ductility. This latter observation is based on the presence of dimples on the grain facets, indicating that some ductile deformation occurred near the grain boundaries. The material failed without any reduction in area at 450 C and 3.9 {times} 10{sup {minus}4} s{sup {minus}1}, and in several cases failed prematurely.

  7. Opposed jet diffusion flames of nitrogen-diluted hydrogen vs air - Axial LDA and CARS surveys; fuel/air rates at extinction

    SciTech Connect

    Pellett, G.L.; Northam, G.B.; Wilson, L.G.; Jarrett, O. Jr.; Antcliff, R.R.

    1989-01-01

    An experimental study of H-air counterflow diffusion flames (CFDFs) is reported. Coaxial tubular opposed jet burners were used to form dish-shaped CFDFs centered by opposing laminar jets of H2/N2 and air in an argon bath at 1 atm. Jet velocities for extinction and flame restoration limits are shown versus input H2 concentration. LDA velocity data and CARS temperature and absolute N2, O2 density data give detailed flame structure on the air side of the stagnation point. The results show that air jet velocity is a more fundamental and appropriate measure of H2-air CFDF extinction than input H2 mass flux or fuel jet velocity. It is proposed that the observed constancy of air jet velocity for fuel mixtures containing 80 to 100 percent H2 measure a maximum, kinetically controlled rate at which the CFDF can consume oxygen in air. Fuel velocity mainly measures the input jet momentum required to center an H2/N2 versus air CFDF. 42 refs.

  8. Opposed jet diffusion flames of nitrogen-diluted hydrogen vs air - Axial LDA and CARS surveys; fuel/air rates at extinction

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. B.; Wilson, L. G.; Jarrett, Olin, Jr.; Antcliff, R. R.

    1989-01-01

    An experimental study of H-air counterflow diffusion flames (CFDFs) is reported. Coaxial tubular opposed jet burners were used to form dish-shaped CFDFs centered by opposing laminar jets of H2/N2 and air in an argon bath at 1 atm. Jet velocities for extinction and flame restoration limits are shown versus input H2 concentration. LDA velocity data and CARS temperature and absolute N2, O2 density data give detailed flame structure on the air side of the stagnation point. The results show that air jet velocity is a more fundamental and appropriate measure of H2-air CFDF extinction than input H2 mass flux or fuel jet velocity. It is proposed that the observed constancy of air jet velocity for fuel mixtures containing 80 to 100 percent H2 measure a maximum, kinetically controlled rate at which the CFDF can consume oxygen in air. Fuel velocity mainly measures the input jet momentum required to center an H2/N2 versus air CFDF.

  9. Impact of heating and air conditioning system operation and leakage on ventilation and intercompartment transport: studies in unoccupied and occupied Tennessee Valley homes.

    PubMed

    Matthews, T G; Wilson, D L; Thompson, C V; Monar, K P; Dudney, C S

    1990-02-01

    Forced-air heating and air conditioning (HAC) systems caused an average and maximum increase in air infiltration rates of 1.8- and 4.3-fold, respectively, during brief whole-house studies of tracer gas decay in 39 occupied houses. An average increase in air infiltration rate of 0.33 +/- 0.37 h-1 corresponded to an incremental air leak of 240 m3/h, based on approximate house volume. More detailed tracer gas decay studies were performed in basement, kitchen and bedroom locations of six homes with low air infiltration rates (i.e., less than 0.25 h-1). The HAC mixed the indoor air efficiently between measurement sites. HAC operation also caused 1.1- to 3.6-fold increases in air infiltration rates, corresponding to absolute increases of 0.02 to 0.1 h-1. In an unoccupied research house, three-fold increases in average air infiltration rate with HAC operation (i.e., from 0.13 to 0.36 h-1) were reduced to two-fold (i.e., from 0.10 to 0.18 h-1) by sealing the external HAC unit and crawlspace ductwork system. This sealing also resulted in a 30 percent reduction in crawlspace-to-indoor transport rates with the HAC turned on. Blower door tests indicated a less than 20 percent reduction in house leakage area.

  10. Environmental Assessment Report for the Proposed Santa Rosa County Reclaimed Water Rapid-rate Infiltration Basin (RIB) System at Eglin Air Force Base, Florida

    DTIC Science & Technology

    2005-02-01

    floridanus Bobcat Lynx rufus Red fox Vulpes vulpes Coyote Canis latrans During site visits in April 2001, June 2002, and January 2003, various anoles...species of plants and 38 animals of conservation concern. Of the 93 species, 62 are considered globally rare (species 39 or subspecies ranking of G3...or higher). Four species or subspecies have a G1 ranking 40 3.0 EXISTING CONDITIONS MGM05-NAVARRE BEACH/ENVIRONMENTAL ASSESSMENT/FINALEA.DOC 3-10 [2

  11. Environmental Assessment Report for the Proposed Santa Rosa County Reclaimed Water Rapid-rate Infiltration Basin (RIB) System at Eglin Air Force Base, Florida

    DTIC Science & Technology

    2005-02-01

    crocodile (Eglin, 2002). 31 There are 64 state-listed species found on Eglin. Most (51) of the 64 state-listed T&E species 32 are plants. Of the 13...RELIGIOUS RESERVOIRS RESIDENTIAL, LOW DENSITY RESIDENTIAL, MEDIUM DENSITY SALTWATER MARSHES SAND AND GRAVEL PITS SHRUB AND BRUSHLAND STREAMS AND...Medium Density 288 Roads and Highways 1 Saltwater Marshes 520 Sand and Gravel Pits 191 Shrub and Brushland 132 Streams and Lake Swamps 60 Streams

  12. Parametric Study of Reactive Melt Infiltration

    NASA Technical Reports Server (NTRS)

    Nelson, Emily S.; Colella, Phillip

    2000-01-01

    Reactive melt infiltration is viewed as a promising means of achieving near-net shape manufacturing with quick processing time and at low cost. Since the reactants and products are, in general, of varying density, overall conservation of mass dictates that there is a force related to chemical conversion which can directly influence infiltration behavior. In effect, the driving pressure forces may compete with the forces from chemical conversion, affecting the advancement of the front. We have developed a two-dimensional numerical code to examine these effects, using reaction-formed silicon carbide as a model system for this process. We have examined a range of initial porosities, pore radii, and reaction rates in order to investigate their effects on infiltration dynamics.

  13. The temperature dependence of ponded infiltration under isothermal conditions

    USGS Publications Warehouse

    Constantz, J.; Murphy, F.

    1991-01-01

    A simple temperature-sensitive modification to the Green and Ampt infiltration equation is described; this assumes that the temperature dependence of the hydraulic conductivity is reciprocally equal to the temperature dependence of the viscosity of liquid water, and that both the transmission zone saturation and the wetting front matric potential gradient are independent of temperature. This modified Green and Ampt equation is compared with ponded, isothermal infiltration experiments run on repacked columns of Olympic Sand and Aiken Loam at 5, 25, and 60??C. Experimental results showed increases in infiltration rates of at least 300% between 5 and 60??C for both soil materials, with subsequent increases in cumulative infiltration of even greater magnitudes for the loam. There is good agreement between measured and predicted initial infiltration rates at 25??C for both soil materials, yet at 60??C, the predicted results overestimate initial infiltration rates for the sand and underestimate initial rates for the loam. Measurements of the wetting depth vs. cumulative infiltration indicate that the transmission zone saturation increased with increasing temperature for both soil materials. In spite of this increased saturation with temperature, the final infiltration rates at both 25 and 60??C were predicted accurately using the modified Green and Ampt equation. This suggests that increased saturation occurred primarily in dead-end pore spaces, so that transmission zone hydraulic conductivities were unaffected by these temperature-induced changes in saturation. In conclusion, except for initial infiltration rates at 60??C, the measured influence of temperature on infiltration rates was fully accounted for by the temperature dependence of the viscosity of liquid water. ?? 1991.

  14. Development rates of two Xenopsylla flea species in relation to air temperature and humidity.

    PubMed

    Krasnov, B R; Khokhlova, I S; Fielden, L J; Burdelova, N V

    2001-09-01

    The rate of development of immature fleas, Xenopsylla conformis Wagner and Xenopsylla ramesis Rothschild (Siphonaptera: Xenopsyllidae) was studied in the laboratory at 25 degrees C and 28 degrees C with 40, 55, 75 and 92% relative humidity (RH). These fleas are separately associated with the host jird Meriones crassus Sundevall in different microhabitats of the Ramon erosion cirque, Negev Highlands, Israel. This study of basic climatic factors in relation to flea bionomics provides the basis for ecological investigations to interpret reasons for paratopic local distributions of these two species of congeneric fleas on the same host. Both air temperature and RH were positively correlated with duration of egg and larval stages in both species. Change of humidity between egg and larval environments did not affect duration of larval development at any temperature. At each temperature and RH, the eggs and larvae of X. ramesis did not differ between males and females in the duration of their development, whereas female eggs and larvae of X. conformis usually developed significantly faster than those of males. For both species, male pupae developed slower than female pupae at the same air temperature and RH. Air temperature, but not RH, affected the duration of pupal development. At each humidity, duration of the pupal stage was significantly longer at 25 degrees C than at 28 degrees C: 15.3+/-1.7 vs. 11.7+/-1.2 days in X. conformis; 14.1+/-2.0 vs. 11.5+/-1.7 days in X. ramesis, with a significantly shorter pupal period of the latter species at 25 degrees C. These limited interspecific bionomic contrasts in relation to basic climatic factors appear insufficient to explain the differential habitat distributions of X. conformis and X. ramesis.

  15. Air exchange rates and alternative vapor entry pathways to inform vapor intrusion exposure risk assessments.

    PubMed

    Reichman, Rivka; Roghani, Mohammadyousef; Willett, Evan J; Shirazi, Elham; Pennell, Kelly G

    2016-11-12

    Vapor intrusion (VI) is a term used to describe indoor air (IA) contamination that occurs due to the migration of chemical vapors in the soil and groundwater. The overall vapor transport process depends on several factors such as contaminant source characteristics, subsurface conditions, building characteristics, and general site conditions. However, the classic VI conceptual model does not adequately account for the physics of airflow around and inside a building and does not account for chemical emissions from alternative "preferential" pathways (e.g. sewers and other utility connections) into IA spaces. This mini-review provides information about recent research related to building air exchange rates (AERs) and alternative pathways to improve the accuracy of VI exposure risk assessment practices. First, results from a recently published AER study for residential homes across the United States (US) are presented and compared to AERs recommended by the US Environmental Protection Agency (USEPA). The comparison shows considerable differences in AERs when season, location, building age, and other factors are considered. These differences could directly impact VI assessments by influencing IA concentration measurements. Second, a conceptual model for sewer gas entry into buildings is presented and a summary of published field studies is reported. The results of the field studies suggest that alternative pathways for vapors to enter indoor spaces warrant consideration. Ultimately, the information presented in this mini-review can be incorporated into a multiple-lines-of-evidence approach for assessing site-specific VI exposure risks.

  16. Influence of air flow rate and backwashing on the hydraulic behaviour of a submerged filter.

    PubMed

    Cobos-Becerra, Yazmin Lucero; González-Martínez, Simón

    2013-01-01

    The aim of this study was to evaluate backwashing effects on the apparent porosity of the filter media and on the hydraulic behaviour of a pilot scale submerged filter, prior to biofilm colonization, under different hydraulic retention times, and different air flow rates. Tracer curves were analysed with two mathematical models for ideal and non-ideal flow (axial dispersion and Wolf and Resnick models). The filter media was lava stones sieved to 4.5 mm. Backwashing causes attrition of media particles, decreasing the void volume of the filter media and, consequently, the tracer flow is more uniform. The eroded media presented lower dead volumes (79% for the filter with aeration and 8% for the filter without aeration) compared with the new media (83% for the filter with aeration and 22% for the filter without aeration). The flow patterns of eroded and new media were different because the more regular shape of the particles decreases the void volume of the filter media. The dead volume is attributed, in the case of the filter with aeration, to the turbulence caused by the air bubbles that generate preferential channelling of the bulk liquid along the filter media, creating large zones of stagnant liquid and, for the filter without aeration, to the channels formed due to the irregular shaped media.

  17. 40 CFR 35.927-1 - Infiltration/inflow analysis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... possible existence of excessive infiltration/inflow in the sewer system. The analysis should identify the presence, flow rate, and type of infiltration/inflow conditions which exist in the sewer system. (b) For... analysis guidelines (Appendix A to this subpart) should be consulted with respect to this determination....

  18. Analysis of turbulent free jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.

    1978-01-01

    The nonequilibrium flow field resulting from the turbulent mixing and combustion of a supersonic axisymmetric hydrogen jet in a supersonic parallel coflowing air stream is analyzed. Effective turbulent transport properties are determined using the (K-epsilon) model. The finite-rate chemistry model considers eight reactions between six chemical species, H, O, H2O, OH, O2, and H2. The governing set of nonlinear partial differential equations is solved by an implicit finite-difference procedure. Radial distributions are obtained at two downstream locations of variables such as turbulent kinetic energy, turbulent dissipation rate, turbulent scale length, and viscosity. The results show that these variables attain peak values at the axis of symmetry. Computed distributions of velocity, temperature, and mass fraction are also given. A direct analytical approach to account for the effect of species concentration fluctuations on the mean production rate of species (the phenomenon of unmixedness) is also presented. However, the use of the method does not seem justified in view of the excessive computer time required to solve the resulting system of equations.

  19. On The Valuation of Infiltration towards Meeting Residential Ventilation Needs

    SciTech Connect

    Sherman, Max H.

    2008-09-01

    The purpose of ventilation is dilute or remove indoor contaminants that an occupant is exposed to. It can be provided by mechanical or natural means. In most homes, especially existing homes, infiltration provides the dominant fraction of the ventilation. As we seek to provide acceptable indoor air quality at minimum energy cost, it is important to neither over-ventilate nor under-ventilate. Thus, it becomes critically important to correctly evaluate the contribution infiltration makes to both energy consumption and equivalent ventilation. ASHRAE Standards including standards 62, 119, and 136 have all considered the contribution of infiltration in various ways, using methods and data from 20 years ago.

  20. Effect on air quality and flow rate of fresh water production in humidification and dehumidification system

    NASA Astrophysics Data System (ADS)

    Rajasekar, K.; Pugazhenthi, R.; Selvaraju, A.; Manikandan, T.; Saravanan, R.

    2017-03-01

    Water is the vital need of any living organisms of the world when water fails, functions of nature cease the world. The water scarcity is one of the major problems to be faced by the developing world, which indicates a critical need to develop inexpensive small-scale desalination technologies. The cost of the desalination process takes more, so the world expecting the desalination plants with minimum operating cost, so the utilization of renewable energy source is a preferable one. This research article provides a glimpse of an overview of the humidification-dehumidification (HDH) based desalination method which uses the solar energy. The HDH based desalination method monitored and evaluated the performance parameters, i.e. mass flow rates of water and air.

  1. Polymer infiltration studies

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.

    1992-01-01

    Progress was made in several areas on the preparation of carbon fiber composites using advanced polymer resins. Polymer infiltration studies dealt with ways of preparing composite materials from advanced polymer resins and carbon fibers. This effort is comprised of an integrated approach to the process of composite part fabrication. The goal is to produce advanced composite materials for automated part fabrication using textile and robotics technology in the manufacture of subsonic and supersonic aircraft. The object is achieved through investigations at the NASA Langley Research Center and by stimulating technology transfer between contract researchers and the aircraft industry. Covered here are literature reviews, a status report on individual projects, current and planned research, publications, and scheduled technical presentations.

  2. Influence of travel speed on spray deposition uniformity from an air-assisted variable-rate sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A newly developed LiDAR-guided air-assisted variable-rate sprayer for nursery and orchard applications was tested at various travel speeds to compare its spray deposition and coverage uniformity with constant-rate applications. Spray samplers, including nylon screens and water-sensitive papers (WSP)...

  3. Space Station Freedom seal leakage rate analysis and testing summary: Air leaks in ambient versus vacuum exit conditions

    NASA Technical Reports Server (NTRS)

    Rodriguez, P. I.; Markovitch, R.

    1992-01-01

    This report is intended to reveal the apparent relationship of air seal leakage rates between 2 atmospheres (atm) to 1 atm and 1 atm to vacuum conditions. Gas dynamics analysis is provided as well as data summarizing the MSFC test report, 'Space Station Freedom (S.S. Freedom) Seal Flaw Study With Delta Pressure Leak Rate Comparison Test Report'.

  4. Chemical characterization of indoor air of homes from communes in Xuan Wei, China, with high lung cancer mortality rates

    EPA Science Inventory

    In a rural county, Xuan Wei, China, the lung cancer mortality rate is among China's highest, especially in women. This mortality rate is more associated with indoor air burning of smoky coal, as opposed to smokeless coal or wood, for cooking and heating under unvented conditions....

  5. Effects of metabolic rate on thermal responses at different air velocities in -10 degrees C.

    PubMed

    Mäkinen, T T; Gavhed, D; Holmér, I; Rintamäki, H

    2001-04-01

    The effects of exercise intensity on thermoregulatory responses in cold (-10 degrees C) in a 0.2 (still air, NoWi), 1.0 (Wi1), and 5.0 (Wi5) m x s(-1) wind were studied. Eight young and healthy men, preconditioned in thermoneutral (+20 degrees C) environment for 60 min, walked for 60 min on the treadmill at 2.8 km/h with different combinations of wind and exercise intensity. Exercise level was adjusted by changing the inclination of the treadmill between 0 degrees (lower exercise intensity, metabolic rate 124 W x m(-2), LE) and 6 degrees (higher exercise intensity, metabolic rate 195 W x m(-2), HE). Due to exercise increased heat production and circulatory adjustments, the rectal temperature (T(re)), mean skin temperature (Tsk) and mean body temperature (Tb) were significantly higher at the end of HE in comparison to LE in NoWi and Wi1, and T(re) and Tb also in Wi5. Tsk and Tb were significantly decreased by 5.0 m x s(-1) wind in comparison to NoWi and Wi1. The higher exercise intensity was intense enough to diminish peripheral vasoconstriction and consequently the finger skin temperature was significantly higher at the end of HE in comparison to LE in NoWi and Wi1. Mean heat flux from the skin was unaffected by the exercise intensity. At LE oxygen consumption (VO2) was significantly higher in Wi5 than NoWi and Wi1. Heart rate was unaffected by the wind speed. The results suggest that, with studied exercise intensities, produced without changes in walking speed, the metabolic rate is not so important that it should be taken into consideration in the calculation of wind chill index.

  6. Spatial and temporal infiltration dynamics during managed aquifer recharge.

    PubMed

    Racz, Andrew J; Fisher, Andrew T; Schmidt, Calla M; Lockwood, Brian S; Los Huertos, Marc

    2012-01-01

    Natural groundwater recharge is inherently difficult to quantify and predict, largely because it comprises a series of processes that are spatially distributed and temporally variable. Infiltration ponds used for managed aquifer recharge (MAR) provide an opportunity to quantify recharge processes across multiple scales under semi-controlled conditions. We instrumented a 3-ha MAR infiltration pond to measure and compare infiltration patterns determined using whole-pond and point-specific methods. Whole-pond infiltration was determined by closing a transient water budget (accounting for inputs, outputs, and changes in storage), whereas point-specific infiltration rates were determined using heat as a tracer and time series analysis at eight locations in the base of the pond. Whole-pond infiltration, normalized for wetted area, rose rapidly to more than 1.0 m/d at the start of MAR operations (increasing as pond stage rose), was sustained at high rates for the next 40 d, and then decreased to less than 0.1 m/d by the end of the recharge season. Point-specific infiltration rates indicated high spatial and temporal variability, with the mean of measured values generally being lower than rates indicated by whole-pond calculations. Colocated measurements of head gradients within saturated soils below the pond were combined with infiltration rates to calculate soil hydraulic conductivity. Observations indicate a brief period of increasing saturated hydraulic conductivity, followed by a decrease of one to two orders of magnitude during the next 50 to 75 d. Locations indicating the most rapid infiltration shifted laterally during MAR operation, and we suggest that infiltration may function as a "variable source area" processes, conceptually similar to catchment runoff.

  7. Effectiveness of traffic-related elements in tree bark and pollen abortion rates for assessing air pollution exposure on respiratory mortality rates.

    PubMed

    Carvalho-Oliveira, Regiani; Amato-Lourenço, Luís F; Moreira, Tiana C L; Silva, Douglas R Rocha; Vieira, Bruna D; Mauad, Thais; Saiki, Mitiko; Saldiva, Paulo H Nascimento

    2017-02-01

    The majority of epidemiological studies correlate the cardiorespiratory effects of air pollution exposure by considering the concentrations of pollutants measured from conventional monitoring networks. The conventional air quality monitoring methods are expensive, and their data are insufficient for providing good spatial resolution. We hypothesized that bioassays using plants could effectively determine pollutant gradients, thus helping to assess the risks associated with air pollution exposure. The study regions were determined from different prevalent respiratory death distributions in the Sao Paulo municipality. Samples of tree flower buds were collected from twelve sites in four regional districts. The genotoxic effects caused by air pollution were tested through a pollen abortion bioassay. Elements derived from vehicular traffic that accumulated in tree barks were determined using energy-dispersive X-ray fluorescence spectrometry (EDXRF). Mortality data were collected from the mortality information program of Sao Paulo City. Principal component analysis (PCA) was applied to the concentrations of elements accumulated in tree barks. Pearson correlation and exponential regression were performed considering the elements, pollen abortion rates and mortality data. PCA identified five factors, of which four represented elements related to vehicular traffic. The elements Al, S, Fe, Mn, Cu, and Zn showed a strong correlation with mortality rates (R(2)>0.87) and pollen abortion rates (R(2)>0.82). These results demonstrate that tree barks and pollen abortion rates allow for correlations between vehicular traffic emissions and associated outcomes such as genotoxic effects and mortality data.

  8. Pyrolysis of polymeric materials. I - Effect of chemical structure, temperature, heating rate, and air flow on char yield and toxicity

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Casey, C. J.

    1979-01-01

    Various polymeric materials, including synthetic polymers and cellulosic materials, were evaluated at different temperatures, heating rates and air flow rates for thermophysical and toxicological responses. It is shown that char yields appeared to be a function of air access as much as of the chemical structure of the material. It is stated that the sensitivity of the apparent thermal stability of some materials to air access is so marked that thermogravimetric studies in oxygen-free atmospheres may be a consistently misleading approach to comparing synthetic polymers intended to increase fire safety. Toxicity also appeared to be a function of temperature and air access as much as of the chemical structure of the material. Toxicity of the gases evolved seemed to increase with increasing char yield for some polymers.

  9. Analysis of turbulent free-jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.; Glass, I. I.; Evans, J. S.

    1979-01-01

    A numerical analysis is presented of the nonequilibrium flow field resulting from the turbulent mixing and combustion of an axisymmetric hydrogen jet in a supersonic parallel ambient air stream. The effective turbulent transport properties are determined by means of a two-equation model of turbulence. The finite-rate chemistry model considers eight elementary reactions among six chemical species: H, O, H2O, OH, O2 and H2. The governing set of nonlinear partial differential equations was solved by using an implicit finite-difference procedure. Radial distributions were obtained at two downstream locations for some important variables affecting the flow development, such as the turbulent kinetic energy and its dissipation rate. The results show that these variables attain their peak values on the axis of symmetry. The computed distribution of velocity, temperature, and mass fractions of the chemical species gives a complete description of the flow field. The numerical predictions were compared with two sets of experimental data. Good qualitative agreement was obtained.

  10. Uneven futures of human lifespans: reckonings from Gompertz mortality rates, climate change, and air pollution.

    PubMed

    Finch, Caleb E; Beltrán-Sánchez, Hiram; Crimmins, Eileen M

    2014-01-01

    The past 200 years have enabled remarkable increases in human lifespans through improvements in the living environment that have nearly eliminated infections as a cause of death through improved hygiene, public health, medicine, and nutrition. We argue that the limit to lifespan may be approaching. Since 1997, no one has exceeded Jeanne Calment's record of 122.5 years, despite an exponential increase of centenarians. Moreover, the background mortality may be approaching a lower limit. We calculate from Gompertz coefficients that further increases in longevity to approach a life expectancy of 100 years in 21st century cohorts would require 50% slower mortality rate accelerations, which would be a fundamental change in the rate of human aging. Looking into the 21st century, we see further challenges to health and longevity from the continued burning of fossil fuels that contribute to air pollution as well as global warming. Besides increased heat waves to which elderly are vulnerable, global warming is anticipated to increase ozone levels and facilitate the spread of pathogens. We anticipate continuing socioeconomic disparities in life expectancy.

  11. Model-based flow rate control for an orfice-type low-volume air sampler

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The standard method of measuring air suspended particulate matter concentration per volume of air consists of continuously drawing a defined volume of air across a filter over an extended period of time, then measuring the mass of the filtered particles and dividing it by the total volume sampled ov...

  12. Relationships between strength and endurance parameters and air depletion rates in professional firefighters.

    PubMed

    Windisch, Stephanie; Seiberl, Wolfgang; Schwirtz, Ansgar; Hahn, Daniel

    2017-03-17

    The aim of this study was to quantify the physical demands of a simulated firefighting circuit and to establish the relationship between job performance and endurance and strength fitness measurements. On four separate days 41 professional firefighters (39 ± 9 yr, 179.6 ± 2.3 cm, 84.4 ± 9.2 kg, BMI 26.1 ± 2.8 kg/m(2)) performed treadmill testing, fitness testing (strength, balance and flexibility) and a simulated firefighting exercise. The firefighting exercise included ladder climbing (20 m), treadmill walking (200 m), pulling a wire rope hoist (15 times) and crawling an orientation section (50 m). Firefighting performance during the simulated exercise was evaluated by a simple time-strain-air depletion model (TSA) taking the sum of z-transformed parameters of time to finish the exercise, strain in terms of mean heart rate, and air depletion from the breathing apparatus. Multiple regression analysis based on the TSA-model served for the identification of the physiological determinants most relevant for professional firefighting. Three main factors with great influence on firefighting performance were identified (70.1% of total explained variance): VO2peak, the time firefighter exercised below their individual ventilatory threshold and mean breathing frequency. Based on the identified main factors influencing firefighting performance we recommend a periodic preventive health screening for incumbents to monitor peak VO2 and individual ventilatory threshold.

  13. Relationships between strength and endurance parameters and air depletion rates in professional firefighters

    PubMed Central

    Windisch, Stephanie; Seiberl, Wolfgang; Schwirtz, Ansgar; Hahn, Daniel

    2017-01-01

    The aim of this study was to quantify the physical demands of a simulated firefighting circuit and to establish the relationship between job performance and endurance and strength fitness measurements. On four separate days 41 professional firefighters (39 ± 9 yr, 179.6 ± 2.3 cm, 84.4 ± 9.2 kg, BMI 26.1 ± 2.8 kg/m2) performed treadmill testing, fitness testing (strength, balance and flexibility) and a simulated firefighting exercise. The firefighting exercise included ladder climbing (20 m), treadmill walking (200 m), pulling a wire rope hoist (15 times) and crawling an orientation section (50 m). Firefighting performance during the simulated exercise was evaluated by a simple time-strain-air depletion model (TSA) taking the sum of z-transformed parameters of time to finish the exercise, strain in terms of mean heart rate, and air depletion from the breathing apparatus. Multiple regression analysis based on the TSA-model served for the identification of the physiological determinants most relevant for professional firefighting. Three main factors with great influence on firefighting performance were identified (70.1% of total explained variance): VO2peak, the time firefighter exercised below their individual ventilatory threshold and mean breathing frequency. Based on the identified main factors influencing firefighting performance we recommend a periodic preventive health screening for incumbents to monitor peak VO2 and individual ventilatory threshold. PMID:28303944

  14. Measurement of air exchange rate of stationary vehicles and estimation of in-vehicle exposure.

    PubMed

    Park, J H; Spengler, J D; Yoon, D W; Dumyahn, T; Lee, K; Ozkaynak, H

    1998-01-01

    The air exchange rates or air changes per hour (ACH) were measured under 4 conditions in 3 stationary automobiles. The ACH ranged between 1.0 and 3.0 h-1 with windows closed and no mechanical ventilation, between 1.8 and 3.7 h-1 for windows closed with fan set on recirculation, between 13.3 and 26.1 h-1 for window open with no mechanical ventilation, and between 36.2 and 47.5 h-1 for window closed with the fan set on fresh air. ACHs for windows closed with no ventilation were higher for the older automobile than for the newer automobiles. With the windows closed and fan turned off, ACH was not influenced by wind speed (p > 0.05). When the window was open, ACH appeared to be greatly affected by wind speed (R2 = 0.86). These measurements are relevant to understanding exposures inside automobiles to sources such as dry-cleaned clothes, cigarettes and airbags. Therefore, to understand the in-vehicle exposure to these internal sources, perchloroethylene (PCE) emitted from dry-cleaned clothes and environmental tobacco smoke (ETS) inside a vehicle were modeled for simulated driving cycles. Airbag deployment was also modeled for estimating exposure level to alkaline particulate and carbon monoxide (CO). Average exposure to PCE inside a vehicle for 30 minutes period was high (approximately 780 micrograms/m3); however, this is only 6% of the two-week exposure that is influenced by the storage of dry cleaned clothing at home. On the other hand, the exposure levels of respirable suspended particulate (RSP) and formaldehyde due to ETS could reach 2.1 mg/m3 and 0.11 ppm, respectively, when a person smokes inside a driving car even with the window open. In modeling the in-vehicle concentrations following airbag deployment, the average CO level over 20 minutes would not appear to present problem (less than 28 ppm). The peak concentration of respirable particulate would have exceeded 140 mg/m3. Since most of the particle mass is composed of alkaline material, these high levels

  15. Transient Point Infiltration In The Unsaturated Zone

    NASA Astrophysics Data System (ADS)

    Buecker-Gittel, M.; Mohrlok, U.

    The risk assessment of leaking sewer pipes gets more and more important due to urban groundwater management and environmental as well as health safety. This requires the quantification and balancing of transport and transformation processes based on the water flow in the unsaturated zone. The water flow from a single sewer leakage could be described as a point infiltration with time varying hydraulic conditions externally and internally. External variations are caused by the discharge in the sewer pipe as well as the state of the leakage itself. Internal variations are the results of microbiological clogging effects associated with the transformation processes. Technical as well as small scale laboratory experiments were conducted in order to investigate the water transport from an transient point infiltration. From the technical scale experiment there was evidence that the water flow takes place under transient conditions when sewage infiltrates into an unsaturated soil. Whereas the small scale experiments investigated the hydraulics of the water transport and the associated so- lute and particle transport in unsaturated soils in detail. The small scale experiment was a two-dimensional representation of such a point infiltration source where the distributed water transport could be measured by several tensiometers in the soil as well as by a selective measurement of the discharge at the bottom of the experimental setup. Several series of experiments were conducted varying the boundary and initial con- ditions in order to derive the important parameters controlling the infiltration of pure water from the point source. The results showed that there is a significant difference between the infiltration rate in the point source and the discharge rate at the bottom, that could be explained by storage processes due to an outflow resistance at the bottom. This effect is overlayn by a decreasing water content decreases over time correlated with a decreasing infiltration

  16. [Lung infiltrations in Hodgkin lymphoma].

    PubMed

    Ciurea-Löchel, A; Ciurea, A; Stey, C; Pestalozzi, B

    2001-08-02

    We report the case of a young patient presenting with cervical lymphadenopathy and interstitial pulmonary infiltrates due to Hodgkin's Disease. Although lung involvement regressed under chemotherapy, we observed new alveolar infiltrates during treatment. Steroid administration after exclusion of an infectious cause was followed by rapid clinical and radiological improvement, indicating the probable presence of pulmonary bleomycine toxicity.

  17. Ring Infiltrate in Staphylococcal Keratitis

    PubMed Central

    Wallang, Batriti S.; Sharma, Savitri; Sahu, Srikant K.; Mittal, Ruchi

    2013-01-01

    Smear and culture tests of corneal scrapings from a patient with a ring infiltrate confirmed significant growth of a Staphylococcus species resistant to fluoroquinolones. Because of nonresponse to medical management, the patient underwent therapeutic penetrating keratoplasty. Staphylococcal infection of the cornea may appear as a ring-like infiltrate that is recalcitrant to medical management. PMID:23100354

  18. [Mathematical simulation of point source average infiltration depth under film hole irrigation].

    PubMed

    Sun, Xiu-Juan; Ma, Xiao-Yi; Liu, Ji-Long; Zhan, Guo-Long

    2010-03-01

    By using RETC and SWMS-3D software, the point source infiltration characteristics of several typical soils under film hole irrigation were simulated, with the infiltration characteristics and related affecting factors analyzed. One simplified point source infiltration model with the parameters opening film hole rate, film hole diameter, soil clay particle content, and soil bulk density was established, and tested by infiltration experiments with the typical soils from Loess Plateau. It was shown that the infiltration coefficient under film hole irrigation increased with increasing opening film hole rate and decreased with increasing film hole diameter and soil clay particle content, while the infiltration index decreased with increasing opening film hole rate and soil clay particle content. This model could simply and accurately reflect the point source infiltration characteristics under film hole irrigation, and credibly determine the infiltration coefficient and index.

  19. Comparison BIPM.RI(I)-K8 of high dose rate 192Ir brachytherapy standards for reference air kerma rate of the NPL and the BIPM

    NASA Astrophysics Data System (ADS)

    Alvarez, J. T.; Sander, T.; de Pooter, J. A.; Allisy-Roberts, P. J.; Kessler, C.

    2014-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate brachytherapy sources of the National Physical Laboratory (NPL), United Kingdom, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the NPL in June 2010. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the NPL and the BIPM standards for reference air kerma rate, is 0.9989 with a combined standard uncertainty of 0.0057. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  20. Modelling evolution of air dose rates in river basins in Fukushima Prefecture affected by sediment-sorbed radiocesium redistribution

    NASA Astrophysics Data System (ADS)

    Malins, A.; Sakuma, K.; Nakanishi, T.; Kurikami, H.; Machida, M.; Kitamura, A.; Yamada, S.

    2015-12-01

    The radioactive 134Cs and 137Cs isotopes deposited over Fukushima Prefecture by the Fukushima Daiichi nuclear disaster are the predominant radiological concern for the years following the accident. This is because the energetic gamma radiation they emit on decay constitutes the majority of the elevated air dose rates that now afflict the region. Therefore, we developed a tool for calculating air dose rates from arbitrary radiocesium spatial distributions across the land surface and depth profiles within the ground. As cesium is strongly absorbed by clay soils, its primary redistribution mechanism within Fukushima Prefecture is by soil erosion and water-borne sediment transport. Each year between 0.1~1% of the total radiocesium inventory in the river basins neighboring Fukushima Daiichi is eroded from the land surface and enters into water courses, predominantly during typhoon storms. Although this is a small amount in relative terms, in absolute terms it corresponds to terabecquerels of 134Cs and 137Cs redistribution each year and this can affect the air dose rate at locations of high erosion and sediment deposition. This study inputs the results of sediment redistribution simulations into the dose rate evaluation tool to calculate the locations and magnitude of air dose rate changes due to radiocesium redistribution. The dose rate calculations are supported by handheld survey instrument results taken within the Prefecture.

  1. MO-D-213-07: RadShield: Semi- Automated Calculation of Air Kerma Rate and Barrier Thickness

    SciTech Connect

    DeLorenzo, M; Wu, D; Rutel, I; Yang, K

    2015-06-15

    Purpose: To develop the first Java-based semi-automated calculation program intended to aid professional radiation shielding design. Air-kerma rate and barrier thickness calculations are performed by implementing NCRP Report 147 formalism into a Graphical User Interface (GUI). The ultimate aim of this newly created software package is to reduce errors and improve radiographic and fluoroscopic room designs over manual approaches. Methods: Floor plans are first imported as images into the RadShield software program. These plans serve as templates for drawing barriers, occupied regions and x-ray tube locations. We have implemented sub-GUIs that allow the specification in regions and equipment for occupancy factors, design goals, number of patients, primary beam directions, source-to-patient distances and workload distributions. Once the user enters the above parameters, the program automatically calculates air-kerma rate at sampled points beyond all barriers. For each sample point, a corresponding minimum barrier thickness is calculated to meet the design goal. RadShield allows control over preshielding, sample point location and material types. Results: A functional GUI package was developed and tested. Examination of sample walls and source distributions yields a maximum percent difference of less than 0.1% between hand-calculated air-kerma rates and RadShield. Conclusion: The initial results demonstrated that RadShield calculates air-kerma rates and required barrier thicknesses with reliable accuracy and can be used to make radiation shielding design more efficient and accurate. This newly developed approach differs from conventional calculation methods in that it finds air-kerma rates and thickness requirements for many points outside the barriers, stores the information and selects the largest value needed to comply with NCRP Report 147 design goals. Floor plans, parameters, designs and reports can be saved and accessed later for modification and recalculation

  2. Dynamic evaluation of airflow rates for a variable air volume system serving an open-plan office.

    PubMed

    Mai, Horace K W; Chan, Daniel W T; Burnett, John

    2003-09-01

    In a typical air-conditioned office, the thermal comfort and indoor air quality are sustained by delivering the amount of supply air with the correct proportion of outdoor air to the breathing zone. However, in a real office, it is not easy to measure these airflow rates supplied to space, especially when the space is served by a variable air volume (VAV) system. The most accurate method depends on what is being measured, the details of the building and types of ventilation system. The constant concentration tracer gas method as a means to determine ventilation system performance, however, this method becomes more complicated when the air, including the tracer gas is allowed to recirculate. An accurate measurement requires significant resource support in terms of instrumentation set up and also professional interpretation. This method deters regular monitoring of the performance of an airside systems by building managers, and hence the indoor environmental quality, in terms of thermal comfort and indoor air quality, may never be satisfactory. This paper proposes a space zone model for the calculation of all the airflow parameters based on tracer gas measurements, including flow rates of outdoor air, VAV supply, return space, return and exfiltration. Sulphur hexafluoride (SF6) and carbon dioxide (CO2) are used as tracer gases. After using both SF6 and CO2, the corresponding results provide a reference to justify the acceptability of using CO2 as the tracer gas. The validity of using CO2 has the significance that metabolic carbon dioxide can be used as a means to evaluate real time airflow rates. This approach provides a practical protocol for building managers to evaluate the performance of airside systems.

  3. Modeling runoff and microbial overland transport with KINEROS2/STWIR model: Accuracy and uncertainty as affected by source of infiltration parameters

    EPA Science Inventory

    Infiltration is important to modeling the overland transport of microorganisms in environmental waters. In watershed- and hillslope scale-models, infiltration is commonly described by simple equations relating infiltration rate to soil saturated conductivity and by empirical para...

  4. Induced infiltration in aquifers with ambient flow

    NASA Astrophysics Data System (ADS)

    Wilson, John L.

    1993-10-01

    Well water quality depends on the relative amounts of water drawn from the pumped aquifer and nearby surface water bodies, such as streams, lakes, and wetlands. Although a surface water body may normally gain water from the aquifer, pumping can reverse gradients, causing it to lose water near the well. Surface water then enters the well by induced infiltration. Two-dimensional vertically integrated models of induced infiltration are developed for various combinations of aquifer geometry and sources of recharge. The models, which have applications in wellhead protection, aquifer pollution characterization, and aquifer remediation, are presented graphically. They show that the propensity for and rate of induced infiltration are enhanced by higher pumping rates, proximity of the well to the stream, and the presence of nearby barrier boundaries. The propensity and rate are reduced by the presence of other surface water bodies. Ambient groundwater discharge rate to the surface water body also plays a role, but not its source, whether it is from local vertical recharge, lateral inflow, or both. The results are also largely indifferent to whether the aquifer transmissivity is assumed to be a constant, or a function of water table elevation. Finally, if the well is close enough to the surface water body, say, less than 5% of the aquifer width, then the aquifer acts as if it were semi-infinite.

  5. E-beam treatment of trichloroethylene-air mixtures: Products and rates

    NASA Astrophysics Data System (ADS)

    Mill, Theodore; Su, Minggong; David Yao, C. C.; Matthews, Stephen M.; Wang, Francis T. S.

    1997-09-01

    Electron beam (E-beam) treatment of 3000 ppmv trichloroethylene (TCE) vapor in dry and wet air led to rapid, nearly quantitative, conversion of TCE to dichloroacetyl chloride, plus small amounts of phosgene. Higher E-beam doses, up to 110 kGy, led to oxidation of the initial products to CO, CO 2, HCl and Cl 2. The results parallel results found for photo- and Cl-atom initiated oxidation of TCE vapor, and are accounted for by an efficient Cl-atom chain oxidation. Lack of effect of 28,000 ppmv water vapor (90% RH) on rates or products reflects a very high efficiency for the Cl-atom chain oxidation and the very slow reaction of vapor phase water with acyl halides. Irradiation experiments conducted with TCE dissolved in aerated and deaerated water at 10 and 300 ppm showed marked differences in radiolytic products from those found in the vapor phase. A preliminary cost estimate indicates that E-beam treatment of TCE vapor is very competitive with conventional activated carbon treatment and catalytic oxidation.

  6. Influence of experimental set-up on the infiltration characteristics during managed aquifer recharge operation

    NASA Astrophysics Data System (ADS)

    Fichtner, Thomas; Vanzella de Melo, Julio Augusto; Stefan, Catalin

    2016-04-01

    The main focus during operation of managed aquifer recharge (MAR) is on clogging processes, specifically on the changes of infiltration capacities and degradation of infiltrated organic substances including vadose zone oxygen dynamics. Lab scale experiments are one opportunity to understand and characterize these processes under different drying and wetting cycles and infiltration rates. However, the multitude of assumptions and scale-related limitations of downscale investigations often lead to over- or underestimations, rendering their results useless when translated to field-like conditions. Therefore, the specific objective of this investigation is to compare the results obtained from two different experimental set-ups with different scales: a 3D, rectangular shaped, stainless steel lysimeter (1.5 x 1.0 x 1.0 m) with an infiltration basin installed in the centre of its surface and a 1D soil column (1m, ᴓ 0.15 m) with the infiltration over the complete column surface. The study focuses on the influence of the experimental setup conditions on the soil clogging, water flow pattern, oxygen dynamics and degradation of organic substances. The results should allow making statements about the suitability of these lab experiments for the investigation of processes taking place in the unsaturated soil zone during operation of MAR. Both experimental units were packed with the same soil and equipped with tensiometers, TDR-probes, oxygen probes and suction cups in two depths for the estimation of spatial and temporal distribution of soil moisture, oxygen and infiltrated substances. The lysimeter and the column were placed inside of a fully automatic climate tent, which facilitates the exact control of air temperature and humidity. The first results confirm that both infiltration units are suitable to simulate the clogging and the oxidation of easily degradable organic substances. However, the velocity of water transport is higher in the column compared with the lysimeter

  7. Measuring OutdoorAir Intake Rates Using Electronic Velocity Sensors at Louvers and Downstream of Airflow Straighteners

    SciTech Connect

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2008-10-01

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100percent, and were often greater than 25percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  8. Humic substance formation during wastewater infiltration

    SciTech Connect

    Siegrist, R.L. ); Hildmann-Smed, R.; Filip, Z.K. , Langen . Inst. fuer Wasser-, Boden- und Lufthygiene); Jenssen, P.D. . Centre for Soil and Environmental Research)

    1991-01-01

    Soil infiltration of wastewater effluents is a widely practiced method of treatment and disposal/reuse throughout the world. Renovation of the wastewater results from a wide variety of complex physicochemical and biological processes. One set of processes is speculated to involve the accumulation of organic matter by filtration and sorption followed by formation of humic substances. This humic substance formation can effect the performance of soil treatment systems by contributing to soil pore clogging and reduction in hydraulic capacity, and by yielding reactive substances and an enhancement of purification processes. While there has been a wealth of research into the nature and genesis of humic substances in terrestrial environments, there has been limited research of humic substance formation during soil infiltration of wastewater. The purpose of the research reported herein was to determine if humic substances can form under conditions typical of those present during wastewater infiltration into natural soil systems. This work was conducted during 1989 to 1990 as a collaborative effort between the Centre for Soil and Environmental Research, located in Aas, Norway and the Institute for Water, Soil and Air Hygiene located in Langen, West Germany. 11 refs., 3 figs., 6 tabs.

  9. The effect of low ventilation rate with elevated bioeffluent concentration on work performance, perceived indoor air quality and health symptoms.

    PubMed

    Maula, Henna; Hongisto, Valtteri; Naatula, Viivi; Haapakangas, Annu; Koskela, Hannu

    2017-04-05

    The aim of this laboratory experiment was to study the effects of ventilation rate, and related changes in air quality, predominantly bioeffluents, on work performance, perceived indoor air quality and health symptoms in a typical conditions of modern open-plan office with low material and equipment emissions. In Condition A, outdoor air flow rate of 28.2 l/s person (CO2 level 540 ppm) was applied and in Condition B, outdoor air flow rate was 2.3 l/s person (CO2 level 2260 ppm). CO2 concentration level was used as an indicator of bioeffluents. Performance was measured with seven different tasks which measure different cognitive processes. Thirty-six subjects participated in the experiment. The exposure time was 4 hours. Condition B had a weak negative effect on performance only in the information retrieval tasks. Condition B increased slightly subjective workload and perceived fatigue. No effects on health symptoms were found. The intensity of symptoms was low in both conditions. The experimental condition had an effect on perceived air quality and observed odour intensity only in the beginning of the session. Although the room temperature was controlled in both conditions, the heat was perceived to impair the performance more in Condition B. This article is protected by copyright. All rights reserved.

  10. Building ventilation and indoor air quality

    SciTech Connect

    Hollowell, C.D.; Berk, J.V.; Boegel, M.L.; Miksch, R.R.; Nazaroff, W.W.; Traynor, G.W.

    1980-01-01

    Rising energy prices, among other factors, have generated an incentive to reduce ventilation rates and thereby reduce the cost of heating and cooling buildings. Reduced infiltration and ventilation in buildings may significantly increase exposure to indoor contaminants and perhaps have adverse effects on occupant health and comfort. Four indoor air contaminants - carbon monoxide and nitrogen dioxide from gas appliances; formaldehyde from particleboard, plywood, urea-formaldehyde foam insulation, and gas appliances; and radon from building materials, soil, and ground water - are currently receiving considerable attention in the context of potential health risks associated with reduced infiltration and ventilation rates. These air contaminants in conventional and energy efficient buildings were measured and analyzed with a view to assessing their potential health risks and various control strategies capable of lowering pollutant concentrations. Preliminary findings suggest that further intensive studies are needed in order to develop criteria for maintaining acceptable indoor air quality without compromising energy efficiency.

  11. Ablation rate, caries removal, and restoration using Nd:YAG and Er:YAG lasers and air abrasion

    NASA Astrophysics Data System (ADS)

    White, Joel M.

    1998-04-01

    This study evaluated the ablation rate in dentin and enamel of the Nd:YAG laser (1 - 2W, 10Hz) and the Er:YAG laser (1 - 2.5W, 10Hz), compared to the high-speed drill, low-speed drill and air abrasion (fine and extra-fine particle size). Subsequently, the effectiveness of caries removal and restoration in enamel of the Nd:YAG laser at the same powers and pulse repetition rate was compared to the high-speed drill, low-speed drill, and air abrasion. Enamel and dentin of 1mm thick mid-coronal sections from extracted third molars were ablated by Er:YAG laser ((lambda) equals 2.94 micrometer), Nd:YAG laser ((lambda) equals 1.06 micrometer) both with air/water spray, high-speed drill with 300 carbide bur, and low-speed drill with $1/4 round bur and air abrasions at 160 psi, with fine air abrasion at 50 micrometer and extra fine at 27 micrometer particle size. Removal (ablation) rate defined as dentin or enamel thickness divided by time required for perforation of the samples was determined for lasers, drills and air abrasion. Multifactor randomized ANOVA (p less than 0.05) considered removal rate as a function of treatment conditions. Removal Rate (micrometers per second) Enamel Dentin High-speed drill 273 +/- 47.34 493 +/- 1.73 Low-speed drill 0 42 +/- 14.25 Nd:YAG 2W 0 103 +/- 37 Er:YAG 2W 35 +/- 10 348 +/- 101 Air abrasion/fine 220 +/- 27 433 +/- 99 Air abrasion/extra fine 151 +/- 13 203 +/- 30 Er:YAG laser at 2W 10Hz ablated both enamel and dentin faster than the low-speed drill but slower than the high-speed drill, while the Nd:YAG laser at identical power and pulse rate did not ablate healthy enamel but was capable of removing dentin. To determine caries removal rate in enamel, extracted superficial carious molars (n equals 35) that included minimal explorer penetration and radiographic confirmation of caries extent were selected. Samples were randomly distributed into treatment groups: high-speed drill (HS), low-speed drill (LS), Nd:YAG laser (L), Nd:YAG with air

  12. Controls on the variability of net infiltration to desert sandstone

    USGS Publications Warehouse

    Heilweil, V.M.; McKinney, T.S.; Zhdanov, M.S.; Watt, D.E.

    2007-01-01

    As populations grow in and climates and desert bedrock aquifers are increasingly targeted for future development, understanding and quantifying the spatial variability of net infiltration becomes critically important for accurately inventorying water resources and mapping contamination vulnerability. This paper presents a conceptual model of net infiltration to desert sandstone and then develops an empirical equation for its spatial quantification at the watershed scale using linear least squares inversion methods for evaluating controlling parameters (independent variables) based on estimated net infiltration rates (dependent variables). Net infiltration rates used for this regression analysis were calculated from environmental tracers in boreholes and more than 3000 linear meters of vadose zone excavations in an upland basin in southwestern Utah underlain by Navajo sandstone. Soil coarseness, distance to upgradient outcrop, and topographic slope were shown to be the primary physical parameters controlling the spatial variability of net infiltration. Although the method should be transferable to other desert sandstone settings for determining the relative spatial distribution of net infiltration, further study is needed to evaluate the effects of other potential parameters such as slope aspect, outcrop parameters, and climate on absolute net infiltration rates. Copyright 2007 by the American Geophysical Union.

  13. Conjunction of Multizone Infiltration Specialists (COMIS) fundamentals

    SciTech Connect

    Feustel, H.E.; Rayner-Hooson, A.

    1990-05-01

    The COMIS workshop (Conjunction of Multizone Infiltration Specialists) was a joint research effort to develop a multizone infiltration mode. This workshop (October 1988--September 1989) was hosted by the Energy Performance of Buildings Group at Lawrence Berkeley Laboratory's Applied Science Division. The task of the workshop was to develop a detailed multizone infiltration program taking crack flow, HVAC-systems, single-sided ventilation and transport mechanism through large openings into account. This work was accomplished not by investigating into numerical description of physical phenomena but by reviewing the literature for the best suitable algorithm. The numerical description of physical phenomena is clearly a task of IEA-Annex XX Air Flow Patterns in Buildings,'' which will be finished in September 1991. Multigas tracer measurements and wind tunnel data will be used to check the model. The agenda integrated all participants' contributions into a single model containing a large library of modules. The user-friendly program is aimed at researchers and building professionals. From its announcement in December 1986, COMIS was well received by the research community. Due to the internationality of the group, several national and international research programmes were co-ordinated with the COMIS workshop. Colleagues for France, Italy, Japan, The Netherlands, People's Republic of China, Spain, Sweden, Switzerland, and the United States of America were working together on the development of the model. Even though this kind of co-operation is well known in other fields of research, e.g., high energy physics; for the field of building physics it is a new approach. This document contains an overview about infiltration modelling as well as the physics and the mathematics behind the COMIS model. 91 refs., 38 figs., 9 tabs.

  14. EFFECT OF VENTILATION SYSTEMS AND AIR FILTERS ON DECAY RATES OF PARTICLES PRODUCED BY INDOOR SOURCES IN AN OCCUPIED TOWNHOUSE

    EPA Science Inventory

    Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we me...

  15. CHANGES IN HEART RATE VARIABILITY AND LUNG FUNCTION OBSERVED IN NC PATROL TROOPERS EXPOSED TO PM AND AIR TOXICS

    EPA Science Inventory

    Changes in Heart Rate Variability and Lung Function in NC Patrol Troopers exposed to PM and Air Toxics

    Michael Riediker1, Wayne E Cascio1, Robert B Devlin2, Thomas Griggs1&4, Margaret Herbst1, Ronald W Williams3, Steve P McCorquodale4, Philip A Bromberg1
    1) University o...

  16. INVESTIGATING THE INFLUENCE OF RELATIVE HUMIDITY, AIR VELOCITY, AND AMPLIFICATION ON THE EMISSION RATES OF FUNGAL SPORES

    EPA Science Inventory

    The paper discusses the impact of relative humidity (RH), air velocity, and surface growth on the emission rates of fungal spores from the surface of contaminated material. Although the results show a complex interaction of factors, we have determined, for this limited data set,...

  17. Solute Breakthrough During Recurrent Ponded Infiltration Into Heterogeneous Soil

    NASA Astrophysics Data System (ADS)

    Sobotkova, M.; Snehota, M.; Cislerova, M.

    2009-12-01

    Water flow during recurrent ponded infiltration may be influenced by presence of entrapped air in heterogeneous soils. It is assumed that variations of the entrapped air volume cause changes of the water content and flow patterns, with consequences for the solute transport. The aim of this contribution is to investigate the effect of entrapped air on dispersion by means of experiments in laboratory. Two undisturbed samples of sandy loam soils were collected at the experimental sites in the Šumava Mountains and the Jizera Mountains (Czech Republic). Recurrent ponded infiltration, conducted on each soil sample consisted of two or more infiltration runs. The same level of ponding was maintained during each infiltration run at the top of the sample. Water drained freely through the perforated plate at the bottom of the sample. First infiltration run was done into naturally dry soil while subsequent runs were conducted into wetter soil. Suction pressure heads in three heights were continuously measured by tensiometers. Water contents were monitored by TDR probes also in three heights. Outflow fluxes were recorded continuously during the experiments as well as the weight of the sample. During each infiltration run the concentration pulse of potassium bromide solution was applied at the top of the soil core during steady state flow and breakthrough curve was acquired by electrochemical in-line analysis of bromide ions in the effluent. Soil hydraulic properties were obtained by fitting the measured flux, water content and pressure data by the dual permeability model. The dispersion coefficients were determined by fitting a one-dimensional advection-dispersion equation to each breakthrough curve. Differences in the shape of the breakthrough curves obtained for individual infiltration runs will be discussed on the poster. This research has been supported by GACR 103/08/1552.

  18. Solute breakthrough during recurrent ponded infiltration into heterogeneous soil

    NASA Astrophysics Data System (ADS)

    Sobotkova, Martina; Snehota, Michal; Dohnal, Michal; Cislerova, Milena

    2010-05-01

    Water flow during recurrent ponded infiltration may be influenced by presence of entrapped air in heterogeneous soils. It is assumed that variations of the entrapped air volume cause changes of the water content and flow patterns, with consequences for the solute transport. The aim of this contribution is to investigate the effect of entrapped air on dispersion by means of experiments in laboratory. Two undisturbed samples of sandy loam soils were collected at the experimental sites in the Šumava Mountains and the Jizera Mountains (Czech Republic). Packed sample of fine quartz sand was used as a reference. Recurrent ponded infiltration, conducted on each soil sample consisted of two or more infiltration runs. The same level of ponding was maintained during each infiltration run at the top of the sample. Water drained freely through the perforated plate at the bottom of the sample. First infiltration run was done into naturally dry soil while subsequent runs were conducted into wetter soil. Suction pressure heads in three heights were continuously measured by tensiometers. Water contents were monitored by TDR probes also in three heights. Outflow fluxes were recorded continuously during the experiments as well as the weight of the sample. During each infiltration run the concentration pulse of potassium bromide solution was applied at the top of the soil core during steady state flow and breakthrough curve was acquired by electrochemical in-line analysis of bromide ions in the effluent. Soil hydraulic properties were obtained by fitting the measured flux, water content and pressure data by the dual permeability model. The dispersion coefficients were determined by fitting a one-dimensional advection-dispersion equation to each breakthrough curve. Differences in the shape of the breakthrough curves obtained for individual infiltration runs will be discussed on the poster. This research has been supported by GACR 103/08/1552.

  19. The IPEM code of practice for determination of the reference air kerma rate for HDR (192)Ir brachytherapy sources based on the NPL air kerma standard.

    PubMed

    Bidmead, A M; Sander, T; Locks, S M; Lee, C D; Aird, E G A; Nutbrown, R F; Flynn, A

    2010-06-07

    This paper contains the recommendations of the high dose rate (HDR) brachytherapy working party of the UK Institute of Physics and Engineering in Medicine (IPEM). The recommendations consist of a Code of Practice (COP) for the UK for measuring the reference air kerma rate (RAKR) of HDR (192)Ir brachytherapy sources. In 2004, the National Physical Laboratory (NPL) commissioned a primary standard for the realization of RAKR of HDR (192)Ir brachytherapy sources. This has meant that it is now possible to calibrate ionization chambers directly traceable to an air kerma standard using an (192)Ir source (Sander and Nutbrown 2006 NPL Report DQL-RD 004 (Teddington: NPL) http://publications.npl.co.uk). In order to use the source specification in terms of either RAKR, Κ(R) (ICRU 1985 ICRU Report No 38 (Washington, DC: ICRU); ICRU 1997 ICRU Report No 58 (Bethesda, MD: ICRU)), or air kerma strength, S(K) (Nath et al 1995 Med. Phys. 22 209-34), it has been necessary to develop algorithms that can calculate the dose at any point around brachytherapy sources within the patient tissues. The AAPM TG-43 protocol (Nath et al 1995 Med. Phys. 22 209-34) and the 2004 update TG-43U1 (Rivard et al 2004 Med. Phys. 31 633-74) have been developed more fully than any other protocol and are widely used in commercial treatment planning systems. Since the TG-43 formalism uses the quantity air kerma strength, whereas this COP uses RAKR, a unit conversion from RAKR to air kerma strength was included in the appendix to this COP. It is recommended that the measured RAKR determined with a calibrated well chamber traceable to the NPL (192)Ir primary standard is used in the treatment planning system. The measurement uncertainty in the source calibration based on the system described in this COP has been reduced considerably compared to other methods based on interpolation techniques.

  20. A Photonic Crystal Magnetic Field Sensor Using a Shoulder-Coupled Resonant Cavity Infiltrated with Magnetic Fluid

    PubMed Central

    Su, Delong; Pu, Shengli; Mao, Lianmin; Wang, Zhaofang; Qian, Kai

    2016-01-01

    A kind of photonic crystal magnetic field sensor is proposed and investigated numerically. The shoulder-coupled resonant cavity is introduced in the photonic crystal, which is infiltrated with magnetic fluid. Through monitoring the shift of resonant wavelength, the magnetic field sensing is realized. According to the designed infiltration schemes, both the magnetic field sensitivity and full width at half maximum increase with the number of infiltrated air holes. The figure of merit of the structure is defined to evaluate the sensing performance comprehensively. The best structure corresponding to the optimal infiltration scheme with eight air holes infiltrated with magnetic fluid is obtained. PMID:27999254

  1. A Photonic Crystal Magnetic Field Sensor Using a Shoulder-Coupled Resonant Cavity Infiltrated with Magnetic Fluid.

    PubMed

    Su, Delong; Pu, Shengli; Mao, Lianmin; Wang, Zhaofang; Qian, Kai

    2016-12-16

    A kind of photonic crystal magnetic field sensor is proposed and investigated numerically. The shoulder-coupled resonant cavity is introduced in the photonic crystal, which is infiltrated with magnetic fluid. Through monitoring the shift of resonant wavelength, the magnetic field sensing is realized. According to the designed infiltration schemes, both the magnetic field sensitivity and full width at half maximum increase with the number of infiltrated air holes. The figure of merit of the structure is defined to evaluate the sensing performance comprehensively. The best structure corresponding to the optimal infiltration scheme with eight air holes infiltrated with magnetic fluid is obtained.

  2. Strain characteristics of selectively infiltrated photonic crystal fibers

    NASA Astrophysics Data System (ADS)

    Yu, WenBing; Wang, Ying; Tian, Jie

    2015-07-01

    To obtain the strain sensing for the high sensitivity PCF (Photonic Crystal Fibers), the high refractive index mixture is infiltrated into the air hole of the PCF. In this paper, we propose to adjust the infiltrated length of the air hole in order to make the loss maximum. The goal is to realize the PCF sensor with high sensitive strain. The experimental results show that the strain sensitivity is about 4.36 pm / μ ɛ when the infiltrated length is 30mm and the refractive index of the liquid is 1.5. The experimental results are consistent with the simulation ones. This kind of device can apply to the ultrasensitive strain sensing.

  3. Is volcanic air pollution associated with decreased heart-rate variability?

    PubMed Central

    Chow, Dominic C; Grandinetti, Andrew; Fernandez, Ed; Sutton, A J; Elias, Tamar; Brooks, Barbara; Tam, Elizabeth K

    2010-01-01

    Objectives To determine the autonomic cardiovascular control among residents of Hawaii who are exposed to varying levels of volcanic air pollution (vog), which consists largely of sulfur dioxide (SO2) and acid aerosols. Methods In a cross-sectional study between April 2006 and June 2008, the authors measured cardiovagal autonomic function by heart-rate variability (HRV) in 72 healthy individuals who lived in four exposure zones on Hawaii Island: vog-free (n=18); episodic exposure to SO2 >200 ppb and acid aerosol (n=19); chronic exposure to SO2 ≥30 ppb and acid aerosol (n=15); and chronic exposure to acid aerosols (n=20). Individuals with diabetes or heart disease, or who had smoked in the preceding month were excluded. HRV was measured in all subjects during rest, paced breathing and active standing (Ewing manoeuvre). HRV was analysed in time and frequency domains and compared between the four exposure zones. Results There were no significant differences between exposure zones in HRV, in either time or frequency domains, even after adjustment for age, gender, ethnicity and body mass index. There was no significant HRV change in three individuals in whom HRV was measured before and during an exposure to combined SO2 100–250 ppb and concentration of respirable particles of diameter ≤2.5 μ (PM2.5) >500 μg/m3. Age was significantly correlated with time-domain parameters during paced breathing and the Ewing manoeuvre. Conclusions This study of healthy individuals found no appreciable effects of vog on the autonomic nervous system. PMID:21546995

  4. The air dose rate around the Fukushima Dai-ichi Nuclear Power Plant: its spatial characteristics and temporal changes until December 2012.

    PubMed

    Mikami, Satoshi; Maeyama, Takeshi; Hoshide, Yoshifumi; Sakamoto, Ryuichi; Sato, Shoji; Okuda, Naotoshi; Sato, Tetsuro; Takemiya, Hiroshi; Saito, Kimiaki

    2015-01-01

    Distribution maps of air dose rates around the Fukushima Dai-ichi Nuclear Power Plant were constructed using the results of measurement obtained from approximately 6500 locations (at most) per measurement period. The measurements were conducted 1 m above the ground using survey meters in flat and spatially open locations. Spatial distribution and temporal change of the air dose rate in the area were revealed by examining the resultant distribution maps. The observed reduction rate of the air dose rate over the 18 months between June 2011 and December 2012 was greater than that calculated from radioactive decay of radiocesium by 10% in relative percentage except decontaminated sites. This 10% difference in the reduction of the air dose rate can be explained by the mobility of radiocesium in the depth direction. In the region where the air dose rate was lower than 0.25 μSv h(-1) on June 2011, the reduction of the air dose rate was observed to be smaller than that of the other dose rate regions, and it was in fact smaller than the reduction rate caused by radioactive decay alone. In contrast, the reduction rate was larger in regions with higher air dose rates. In flat and spatially open locations, no significant difference in the reduction tendency of air dose rates was observed among different land use classifications (rice fields, farmland, forests, and building sites).

  5. Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature, Relative Humidity, and Air Exchange Rate

    PubMed Central

    Bekö, Gabriel; Timm, Michael; Gustavsen, Sine; Hansen, Erik Wind

    2012-01-01

    Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m3) and were lowest in winter (median, 26 CFU/m3). Indoor bacteria peaked in spring (median, 2,165 CFU/m3) and were lowest in summer (median, 240 CFU/m3). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates. PMID:23001651

  6. Seasonal variations of indoor microbial exposures and their relation to temperature, relative humidity, and air exchange rate.

    PubMed

    Frankel, Mika; Bekö, Gabriel; Timm, Michael; Gustavsen, Sine; Hansen, Erik Wind; Madsen, Anne Mette

    2012-12-01

    Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m(3)) and were lowest in winter (median, 26 CFU/m(3)). Indoor bacteria peaked in spring (median, 2,165 CFU/m(3)) and were lowest in summer (median, 240 CFU/m(3)). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.

  7. Reference dosimetry at the Australian Synchrotron's imaging and medical beamline using free-air ionization chamber measurements and theoretical predictions of air kerma rate and half value layer

    SciTech Connect

    Crosbie, Jeffrey C.; Rogers, Peter A. W.; Stevenson, Andrew W.; Hall, Christopher J.; Lye, Jessica E.; Nordstroem, Terese; Midgley, Stewart M.; Lewis, Robert A.

    2013-06-15

    Purpose: Novel, preclinical radiotherapy modalities are being developed at synchrotrons around the world, most notably stereotactic synchrotron radiation therapy and microbeam radiotherapy at the European Synchrotron Radiation Facility in Grenoble, France. The imaging and medical beamline (IMBL) at the Australian Synchrotron has recently become available for preclinical radiotherapy and imaging research with clinical trials, a distinct possibility in the coming years. The aim of this present study was to accurately characterize the synchrotron-generated x-ray beam for the purposes of air kerma-based absolute dosimetry. Methods: The authors used a theoretical model of the energy spectrum from the wiggler source and validated this model by comparing the transmission through copper absorbers (0.1-3.0 mm) against real measurements conducted at the beamline. The authors used a low energy free air ionization chamber (LEFAC) from the Australian Radiation Protection and Nuclear Safety Agency and a commercially available free air chamber (ADC-105) for the measurements. The dimensions of these two chambers are different from one another requiring careful consideration of correction factors. Results: Measured and calculated half value layer (HVL) and air kerma rates differed by less than 3% for the LEFAC when the ion chamber readings were corrected for electron energy loss and ion recombination. The agreement between measured and predicted air kerma rates was less satisfactory for the ADC-105 chamber, however. The LEFAC and ADC measurements produced a first half value layer of 0.405 {+-} 0.015 and 0.412 {+-} 0.016 mm Cu, respectively, compared to the theoretical prediction of 0.427 {+-} 0.012 mm Cu. The theoretical model based upon a spectrum calculator derived a mean beam energy of 61.4 keV with a first half value layer of approximately 30 mm in water. Conclusions: The authors showed in this study their ability to verify the predicted air kerma rate and x-ray attenuation

  8. Unilateral apical infiltrate as an initial presentation of pulmonary sarcoidosis.

    PubMed

    Tice, A W

    1981-11-01

    A unilateral, apical, pulmonary infiltrate was seen in an Air Force weapon systems officer stationed in the Philippines as an initial presentation of pulmonary sarcoidosis. The most obvious diagnosis for that geographic area is tuberculosis. Diagnosis must be pursued to evaluate all differential possibilities, with resort to open-lung or bronchoscopic biopsy, if necessary.

  9. Passive Microwave Observation of Soil Water Infiltration

    NASA Technical Reports Server (NTRS)

    Jackson, Thomas J.; Schmugge, Thomas J.; Rawls, Walter J.; ONeill, Peggy E.; Parlange, Marc B.

    1997-01-01

    Infiltration is a time varying process of water entry into soil. Experiments were conducted here using truck based microwave radiometers to observe small plots during and following sprinkler irrigation. Experiments were conducted on a sandy loam soil in 1994 and a silt loam in 1995. Sandy loam soils typically have higher infiltration capabilities than clays. For the sandy loam the observed brightness temperature (TB) quickly reached a nominally constant value during irrigation. When the irrigation was stopped the TB began to increase as drainage took place. The irrigation rates in 1995 with the silt loam soil exceeded the saturated conductivity of the soil. During irrigation the TB values exhibited a pattern that suggests the occurrence of coherent reflection, a rarely observed phenomena under natural conditions. These results suggested the existence of a sharp dielectric boundary (wet over dry soil) that was increasing in depth with time.

  10. Authentic Assessment in the Geometry Classroom: Calculating the Classroom Air-Exchange Rate.

    ERIC Educational Resources Information Center

    Erich, David J.

    2002-01-01

    Introduces a room air-exchange activity designed to assess student understanding of the concept of volume. Lists materials for the activity and its procedures. Includes the lesson plan and a student worksheet. (KHR)

  11. Time variations of 222Rn concentration and air exchange rates in a Hungarian cave.

    PubMed

    Nagy, Hedvig Éva; Szabó, Zsuzsanna; Jordán, Gyozo; Szabó, Csaba; Horváth, Akos; Kiss, Attila

    2012-09-01

    A long-term radon concentration monitoring was carried out in the Pál-völgy cave, Budapest, Hungary, for 1.5 years. Our major goal was to determine the time dependence of the radon concentration in the cave to characterise the air exchange and define the most important environmental parameters that influence the radon concentration inside the cave. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were collected simultaneously. The air's radon concentration in the cave varied between 104 and 7776 Bq m(-3), the annual average value was 1884±85 Bq m(-3). The summer to winter radon concentration ratio was as high as 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, the correlation coefficient (R) was 0.76.

  12. Western Mojave Desert, Rate of Progress Demonstration; Proposed Approval of California Air Plan Revision

    EPA Pesticide Factsheets

    EPA is proposing to approve a state implementation plan revision submitted by the State of California to meet Clean Air Act requirements applicable to the Western Mojave Desert (WMD) ozone nonattainment area.

  13. Comparison of Monoenergetic Photon Organ Dose Rate Coefficients for the Female Stylized and Voxel Phantoms Submerged in Air

    DOE PAGES

    Hiller, Mauritius; Dewji, Shaheen Azim

    2017-02-16

    Dose rate coefficients computed using the International Commission on Radiological Protection (ICRP) reference adult female voxel phantom were compared with values computed using the Oak Ridge National Laboratory (ORNL) adult female stylized phantom in an air submersion exposure geometry. This is a continuation of previous work comparing monoenergetic organ dose rate coefficients for the male adult phantoms. With both the male and female data computed, effective dose rate as defined by ICRP Publication 103 was compared for both phantoms. Organ dose rate coefficients for the female phantom and ratios of organ dose rates for the voxel and stylized phantoms aremore » provided in the energy range from 30 to 5 MeV. Analysis of the contribution of the organs to effective dose is also provided. Lastly, comparison of effective dose rates between the voxel and stylized phantoms was within 8% at 100 keV and is <5% between 200 and 5000 keV.« less

  14. To boldly gulp: standard metabolic rate and boldness have context-dependent influences on risk-taking to breathe air in a catfish.

    PubMed

    McKenzie, David J; Belão, Thiago C; Killen, Shaun S; Rantin, F Tadeu

    2015-12-01

    The African sharptooth catfish Clarias gariepinus has bimodal respiration, it has a suprabranchial air-breathing organ alongside substantial gills. We used automated bimodal respirometry to reveal that undisturbed juvenile catfish (N=29) breathed air continuously in normoxia, with a marked diurnal cycle. Air breathing and routine metabolic rate (RMR) increased in darkness when, in the wild, this nocturnal predator forages. Aquatic hypoxia (20% air saturation) greatly increased overall reliance on air breathing. We investigated whether two measures of risk taking to breathe air, namely absolute rates of aerial O2 uptake (ṀO2,air) and the percentage of RMR obtained from air (%ṀO2,air), were influenced by individual standard metabolic rate (SMR) and boldness. In particular, whether any influence varied with resource availability (normoxia versus hypoxia) or relative fear of predation (day versus night). Individual SMR, derived from respirometry, had an overall positive influence on ṀO2,air across all contexts but a positive influence on %ṀO2,air only in hypoxia. Thus, a pervasive effect of SMR on air breathing became most acute in hypoxia, when individuals with higher O2 demand took proportionally more risks. Boldness was estimated as time required to resume air breathing after a fearful stimulus in daylight normoxia (Tres). Although Tres had no overall influence on ṀO2,air or %ṀO2,air, there was a negative relationship between Tres and %ṀO2,air in daylight, in normoxia and hypoxia. There were two Tres response groups, 'bold' phenotypes with Tres below 75 min (N=13) which, in daylight, breathed proportionally more air than 'shy' phenotypes with Tres above 115 min (N=16). Therefore, individual boldness influenced air breathing when fear of predation was high. Thus, individual energy demand and personality did not have parallel influences on the emergent tendency to take risks to obtain a resource; their influences varied in strength with context.

  15. Observation of infiltration experiments with time lapse electrical resistivity tomography

    NASA Astrophysics Data System (ADS)

    Noell, Ursula; Ganz, Christina; Altfelder, Sven; Günther, Thomas; Duijnisveld, Wilhelmus; Grissemann, Christoph

    2010-05-01

    analysed quantitatively. For the first experiment this calculation shows one day after the infiltration about 40% of the infiltrated water being lost to the groundwater. For the second experiment the quantitative interpretation takes into account the increased conductivity of the infiltrating tracer solution compared to the pore water of the vadose zone before infiltration. Another infiltration experiment is done on Loess. Due to the low infiltration rate only about 9l of water could be infiltrated within about 3 h (38mm/h). The time lapse ERT clearly reveals the water remaining close to surface and no sign of resistivity change due to the infiltration is observed to penetrate deeper than 30cm. At this depth the plough pan seems to inhibit the infiltration. The analysis shows the high sensitivity of the ERT method. Although the original water content is quite high and therefore the resistivity changes due to water content changes are small (the flat part of the Archie function) the time lapse ERT inversion depicts the changes of resistivity quite clearly. The experiments show the advantages of ERT measurements to observe the infiltration process in real time. However, the interpretation of such measurements still poses difficulties mainly due to the limited resolution and the ill posedness of the inversion problem of electrical resistivity tomography (ERT). These problems are investigated further in order to advance the applicability of the method to infiltration problems showing signs of preferential flow.

  16. Measurements of air dose rates in and around houses in the Fukushima Prefecture in Japan after the Fukushima accident.

    PubMed

    Matsuda, Norihiro; Mikami, Satoshi; Sato, Tetsuro; Saito, Kimiaki

    2017-01-01

    Measurements of air dose rates for 192 houses in a less contaminated area (<0.5 μSv h(-1)) of the Fukushima Prefecture in Japan were conducted in both living rooms and/or bedrooms using optically stimulated luminescence (OSL) dosimeters and around the houses via a man-borne survey at intervals of several meters. The relation of the two air dose rates (inside and outside) for each house, including the background from natural radionuclides, was divided into several categories, determined by construction materials (light and heavy) and floor number, with the dose reduction factors being expressed as the ratio of the dose inside to that outside the house. For wooden and lightweight steel houses (classed as light), the dose rates inside and outside the houses showed a positive correlation and linear regression with a slope-intercept form due to the natural background, although the degree of correlation was not very high. The regression coefficient, i.e., the average dose reduction factor, was 0.38 on the first floor and 0.49 on the second floor. It was found that the contribution of natural radiation cannot be neglected when we consider dose reduction factors in less contaminated areas. The reductions in indoor dose rates are observed because a patch of ground under each house is not contaminated (this is the so-called uncontaminated effect) since the shielding capability of light construction materials is typically low. For reinforced steel-framed concrete houses (classed as heavy), the dose rates inside the houses did not show a correlation with those outside the houses due to the substantial shielding capability of these materials. The average indoor dose rates were slightly higher than the arithmetic mean value of the outdoor dose rates from the natural background because concrete acts as a source of natural radionuclides. The characteristics of the uncontaminated effect were clarified through Monte Carlo simulations. It was found that there is a great variation

  17. Determination of the Clean Air Delivery Rate (CADR) of Photocatalytic Oxidation (PCO) Purifiers for Indoor Air Pollutants Using a Closed-Loop Reactor. Part I: Theoretical Considerations.

    PubMed

    Dumont, Éric; Héquet, Valérie

    2017-03-06

    This study demonstrated that a laboratory-scale recirculation closed-loop reactor can be an efficient technique for the determination of the Clean Air Delivery Rate (CADR) of PhotoCatalytic Oxidation (PCO) air purification devices. The recirculation closed-loop reactor was modeled by associating equations related to two ideal reactors: one is a perfectly mixed reservoir and the other is a plug flow system corresponding to the PCO device itself. Based on the assumption that the ratio between the residence time in the PCO device and the residence time in the reservoir τP/τR tends to 0, the model highlights that a lab closed-loop reactor can be a suitable technique for the determination of the efficiency of PCO devices. Moreover, if the single-pass removal efficiency is lower than 5% of the treated flow rate, the decrease in the pollutant concentration over time can be characterized by a first-order decay model in which the time constant is proportional to the CADR. The limits of the model are examined and reported in terms of operating conditions (experiment duration, ratio of residence times, and flow rate ranges).

  18. Drying rate and temperature profile for superheated steam vacuum drying and moist air drying of softwood lumber

    SciTech Connect

    Pang, S.; Dakin, M.

    1999-07-01

    Two charges of green radiata pine sapwood lumber were dried, ether using superheated steam under vacuum (90 C, 0.2 bar abs.) or conventionally using hot moist air (90/60 C). Due to low density of the drying medium under vacuum, the circulation velocity used was 10 m/s for superheated steam drying and 5.0 m/s for moist air drying, and in both cases, the flow was unidirectional. In drying, stack drying rate and wood temperatures were measured to examine the differences between the superheated steam drying and drying using hot moist air. The experimental results have shown that the stack edge board in superheated steam drying dried faster than in the hot moist air drying. Once again due to the low density of the steam under vacuum, a prolonged maximum temperature drop across load (TDAL) was observed in the superheated steam drying, however, the whole stack dried slower and the final moisture content distribution was more variable than for conventional hot moist air drying.

  19. Characteristics and verification of a car-borne survey system for dose rates in air: KURAMA-II.

    PubMed

    Tsuda, S; Yoshida, T; Tsutsumi, M; Saito, K

    2015-01-01

    The car-borne survey system KURAMA-II, developed by the Kyoto University Research Reactor Institute, has been used for air dose rate mapping after the Fukushima Dai-ichi Nuclear Power Plant accident. KURAMA-II consists of a CsI(Tl) scintillation detector, a GPS device, and a control device for data processing. The dose rates monitored by KURAMA-II are based on the G(E) function (spectrum-dose conversion operator), which can precisely calculate dose rates from measured pulse-height distribution even if the energy spectrum changes significantly. The characteristics of KURAMA-II have been investigated with particular consideration to the reliability of the calculated G(E) function, dose rate dependence, statistical fluctuation, angular dependence, and energy dependence. The results indicate that 100 units of KURAMA-II systems have acceptable quality for mass monitoring of dose rates in the environment.

  20. Simulation of fluid, heat transport to estimate desert stream infiltration

    USGS Publications Warehouse

    Kulongoski, J.T.; Izbicki, J.A.

    2008-01-01

    In semiarid regions, the contribution of infiltration from intermittent streamflow to ground water recharge may be quantified by comparing simulations of fluid and heat transport beneath stream channels to observed ground temperatures. In addition to quantifying natural recharge, streamflow infiltration estimates provide a means to characterize the physical properties of stream channel sediments and to identify suitable locations for artificial recharge sites. Rates of winter streamflow infiltration along stream channels are estimated based on the cooling effect of infiltrated water on streambed sediments, combined with the simulation of two-dimensional fluid and heat transport using the computer program VS2DH. The cooling effect of ground water is determined by measuring ground temperatures at regular intervals beneath stream channels and nearby channel banks in order to calculate temperature-depth profiles. Additional data inputs included the physical, hydraulic, and thermal properties of unsaturated alluvium, and monthly ground temperatures measurements over an annual cycle. Observed temperatures and simulation results can provide estimates of the minimum threshold for deep infiltration, the variability of infiltration along stream channels, and also the frequency of infiltration events.

  1. California residential indoor air quality study. Volume 2. Carbon monoxide and air exchange rate: A univariate and multivariate analysis. Topical report

    SciTech Connect

    Colome, S.D.; Wilson, A.L.; Tian, Y.

    1994-07-01

    This second volume provides a systematic evaluation of the data set focusing on the relationships of the recorded parameters with the following four outcome measures: indoor 48-hour average CO; net 48-hour average indoor minus outdoor CO; air exchange rates; and maximum 8-hour average indoor CO. Over 350 variables were measured and/or recorded for each house in the pilot study. These parameters included the concentrations of pollutants of interest (CO, benzene, NO2, toluene, radon, formaldehyde, and methane), housing characteristics (e.g., cooking fuel, burner adjustments, proper venting) and occupant practices (e.g., cigarette smoking, heating with the range/oven).

  2. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature.

    PubMed

    Wang, Kaicun; Zhou, Chunlüe

    2015-07-22

    Global analyses of surface mean air temperature (T(m)) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the "warming hole" over the central U.S., are still under debate. Here we show these regional contrasts depend on the calculation methods of T(m). Existing global analyses calculate T(m) from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using T(m) calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2.

  3. Delivery after Operation for Deeply Infiltrating Endometriosis

    PubMed Central

    Allerstorfer, Christina; Enzelsberger, Simon H.; Shebl, Omar Josef; Mayer, Richard Bernhard

    2016-01-01

    Background. It has been suggested that, during pregnancy, endometriosis can cause a variety of disease-related complications. Objectives. The purpose of the study was to find out if women with histologically confirmed endometriosis do have a higher risk of adverse pregnancy outcome and if they suffer from a higher rate of complications during labor. Study Design. 51 women who underwent surgery because of deeply infiltrating endometriosis in the General Hospital Linz and the Women's General Hospital Linz and who gave birth in the Women's General Hospital Linz after the surgery were included in our survey. Results. 31 women (60.8%) had a spontaneous delivery and in 20 women (39.2%) a caesarean section was performed. There were no cases of third- and fourth-degree perineal lacerations. Collectively there were 4 cases (7.8%) of preterm delivery and one case (2.0%) of premature rupture of membranes. In two women (6.5%) a retained placenta was diagnosed. Conclusions. Our study is the first description on delivery modes after surgery for deeply infiltrating endometriosis. We did not find an elevated risk for perineal or vaginal laceration in women with a history of surgery for deeply infiltrating endometriosis, even when a resection of the rectum or of the posterior vaginal wall had been performed. PMID:27517050

  4. Nanosecond discharge in air at atmospheric pressure as an x-ray source with high pulse repetition rates

    NASA Astrophysics Data System (ADS)

    Tarasenko, Victor F.

    2006-02-01

    The properties of x-ray radiation and runaway electrons produced using a nanosecond volume discharge are examined. X-ray radiation at a pulse repetition rate of 3kHz was obtained time in a gas diode filled with air at atmospheric pressure. The current pulse width (FWHM) for runaway electrons generated in the gas diode was ˜100ps. A prepulse was observed on an oscilloscope trace of the main runaway electron beam current.

  5. Nanosecond discharge in air at atmospheric pressure as an x-ray source with high pulse repetition rates

    SciTech Connect

    Tarasenko, Victor F.

    2006-02-20

    The properties of x-ray radiation and runaway electrons produced using a nanosecond volume discharge are examined. X-ray radiation at a pulse repetition rate of 3 kHz was obtained time in a gas diode filled with air at atmospheric pressure. The current pulse width (FWHM) for runaway electrons generated in the gas diode was {approx}100 ps. A prepulse was observed on an oscilloscope trace of the main runaway electron beam current.

  6. Elementary stage rate coefficients of heterogeneous catalytic recombination of dissociated air on thermal protective surfaces from ab initio approach

    NASA Astrophysics Data System (ADS)

    Buchachenko, A. A.; Kroupnov, A. A.; Kovalev, V. L.

    2015-08-01

    Elementary stage rate coefficients of the full system of kinetic equations describing heterogeneous catalytic recombination of the dissociated air on the surfaces of thermal protective ceramic coatings of β-cristobalite and α-Al2O3 are determined using the quantum-mechanical calculations within the framework of cluster models and literature data. Both the impact and associative recombination processes of adsorbed oxygen and nitrogen atoms are taken into account.

  7. THE EFFECT OF SALINITY ON RATES OF ELEMENTAL MERCURY AIR/WATER EXCHANGE

    EPA Science Inventory

    The U.S. EPA laboratory in Athens, Georgia i spursuing the goal of developing a model for describing toxicant vapor phase air/water exchange under all relevant environmental conditions. To date, the two-layer exchange model (suitable for low wind speed conditions) has been modif...

  8. THE ROLE OF AQUEOUS THIN FILM EVAPORATIVE COOLING ON RATES OF ELEMENTAL MERCURY AIR-WATER EXCHANGE UNDER TEMPERATURE DISEQUILIBRIUM CONDITIONS

    EPA Science Inventory

    The technical conununity has only recently addressed the role of atmospheric temperature variations on rates of air-water vapor phase toxicant exchange. The technical literature has documented that: 1) day time rates of elemental mercury vapor phase air-water exchange can exceed ...

  9. Field study of exhaust fans for mitigating indoor air quality problems: Final report

    SciTech Connect

    Grimsrud, D.T.; Szydlowski, R.F.; Turk, B.H.

    1986-09-01

    Residential ventilation in the United States housing stock is provided primarily by infiltration, the natural leakage of outdoor air into a building through cracks and holes in the building shell. Since ventilation is the dominant mechanism for control of indoor pollutant concentrations, low infiltration rates caused fluctuation in weather conditions may lead to high indoor pollutant concentrations. Supplemental mechanical ventilation can be used to eliminate these periods of low infiltration. This study examined effects of small continuously-operating exhaust fan on pollutant concentrations and energy use in residences.

  10. Influence of surface crusting on infiltration of a loess plateau soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface sealing and crusting are common widespread processes that occur in many cultivated soils worldwide, especially in arid and semiarid regions. Soil crusting negatively affects water infiltration, increases surface runoff, reduces seedling emergence, restricts air exchange between the soil and ...

  11. On-site infiltration of road runoff using pervious pavements with subjacent infiltration trenches as source control strategy.

    PubMed

    Fach, S; Dierkes, C

    2011-01-01

    The focus in this work was on subsoil infiltration of stormwater from parking lots. With regard to operation, reduced infiltration performance due to clogging and pollutants in seepage, which may contribute to contaminate groundwater, are of interest. The experimental investigation covered a pervious pavement with a subjacent infiltration trench draining an impervious area of 2 ha. In order to consider seasonal effects on the infiltration performance, the hydraulic conductivity was measured tri-monthly during monitoring with a mobile sprinkling unit. To assess natural deposits jointing, road bed, gravel of infiltration trenches and subsoil were analysed prior to commencement of monitoring for heavy metals, polycyclic aromatic and mineral oil type hydrocarbons. Furthermore, from 22 storm events, water samples of rainfall, surface runoff, seepage and ground water were analysed with regard to the above mentioned pollutants. The study showed that the material used for the joints had a major impact on the initial as well as the final infiltration rates. Due to its poor hydraulic conductivity, limestone gravel should not be used as jointing. Furthermore, it is recommended that materials for the infiltration facilities are ensured free of any contaminants prior to construction. Polycyclic aromatic and mineral oil type hydrocarbons were, with the exception of surface runoff, below detection limits. Heavy metal concentrations of groundwater were with the exception of lead (because of high background concentrations), below the permissible limits.

  12. Determination of dispersion parameters for oxidizing air and the oxidation rate of calcium sulfites in a pilot desulfurization plant

    SciTech Connect

    Burenkov, D.K.; Derevich, I.V.; Rzaev, A.I.

    1995-10-01

    In the effort to remove sulfur oxides from waste gases, the widest use is gained by desulfurization plants based on wet collection of sulfur dioxide in empty absorbers in which a limestone-gypsum suspension is sprayed, with gypsum being produced as a commodity product. Dispersion of oxidizing air in a model liquid and the oxidation rate of calcium sulfites in a suspension contained in the sump of a pilot desulfurization plant absorber are studied experimentally. Flow velocities, bubble trajectories, and oxidation rates were determined and are presented.

  13. Determination of the Clean Air Delivery Rate (CADR) of Photocatalytic Oxidation (PCO) Purifiers for Indoor Air Pollutants Using a Closed-Loop Reactor. Part II: Experimental Results.

    PubMed

    Héquet, Valérie; Batault, Frédéric; Raillard, Cécile; Thévenet, Frédéric; Le Coq, Laurence; Dumont, Éric

    2017-03-06

    The performances of a laboratory PhotoCatalytic Oxidation (PCO) device were determined using a recirculation closed-loop pilot reactor. The closed-loop system was modeled by associating equations related to two ideal reactors: a perfectly mixed reservoir with a volume of VR = 0.42 m³ and a plug flow system corresponding to the PCO device with a volume of VP = 5.6 × 10(-3) m³. The PCO device was composed of a pleated photocatalytic filter (1100 cm²) and two 18-W UVA fluorescent tubes. The Clean Air Delivery Rate (CADR) of the apparatus was measured under different operating conditions. The influence of three operating parameters was investigated: (i) light irradiance I from 0.10 to 2.0 mW·cm(-2); (ii) air velocity v from 0.2 to 1.9 m·s(-1); and (iii) initial toluene concentration C₀ (200, 600, 1000 and 4700 ppbv). The results showed that the conditions needed to apply a first-order decay model to the experimental data (described in Part I) were fulfilled. The CADR values, ranging from 0.35 to 3.95 m³·h(-1), were mainly dependent on the light irradiance intensity. A square root influence of the light irradiance was observed. Although the CADR of the PCO device inserted in the closed-loop reactor did not theoretically depend on the flow rate (see Part I), the experimental results did not enable the confirmation of this prediction. The initial concentration was also a parameter influencing the CADR, as well as the toluene degradation rate. The maximum degradation rate rmax ranged from 342 to 4894 ppbv/h. Finally, this study evidenced that a recirculation closed-loop pilot could be used to develop a reliable standard test method to assess the effectiveness of PCO devices.

  14. Production and Characterization of High Repetition Rate Terahertz Radiation in Femtosecond-Laser-Induced Air Plasma

    DTIC Science & Technology

    2009-03-01

    and plasma signal. The air plasma intensity was measured using a 40 kHz ultrasonic transducer, while the terahertz radiation was measured by a... calibrate the time axis of the streak camera ................................................... 28 8. Processed data used to calibrate the time axis of...field can be measured 5 directly, but is difficult to manipulate and requires bulky waveguides. However, in optics, radiation is viewed as light

  15. Indoor air pollutants, ventilation rate determinants and potential control strategies in Chinese dwellings: A literature review.

    PubMed

    Ye, Wei; Zhang, Xu; Gao, Jun; Cao, Guangyu; Zhou, Xiang; Su, Xing

    2017-05-15

    After nearly twenty years of rapid modernization and urbanization in China, huge achievements have transformed the daily lives of the Chinese people. However, unprecedented environmental consequences in both indoor and outdoor environments have accompanied this progress and have triggered public awareness and demands for improved living standards, especially in residential environments. Indoor pollution data measured for >7000 dwellings (approximately 1/3 were newly decorated and were tested for volatile organic compound (VOC) measurements, while the rest were tested for particles, phthalates and other semi-volatile organic compounds (SVOCs), moisture/mold, inorganic gases and radon) in China within the last ten years were reviewed, summarized and compared with indoor concentration recommendations based on sensory or health end-points. Ubiquitous pollutants that exceed the concentration recommendations, including particulate matter, formaldehyde, benzene and other VOCs, moisture/mold, inorganic gases and radon, were found, indicating a common indoor air quality (IAQ) issue in Chinese dwellings. With very little prevention, oral, inhalation and dermal exposure to those pollutants at unhealthy concentration levels is almost inevitable. CO2, VOCs, humidity and radon can serve as ventilation determinants, each with different ventilation demands and strategies, at typical occupant densities in China; and particle reduction should be a prerequisite for determining ventilation requirements. Two directional ventilation modes would have profound impacts on improving IAQ for Chinese residences are: 1) natural (or window) ventilation with an air cleaner and 2) mechanical ventilation with an air filtration unit, these two modes were reviewed and compared for their applicability and advantages and disadvantages for reducing human exposure to indoor air pollutants. In general, mode 2 can more reliably ensure good IAQ for occupants; while mode 1 is more applicable due to its low

  16. CLIMATIC FORECASTING OF NET INFILTRATION AT YUCCA MOUNTAIN, USING ANALOGUE METEOROLOGICAL DATA

    SciTech Connect

    B. Faybishenko

    2005-09-07

    Net infiltration is a key hydrologic parameter that controls the rate of deep percolation through the unsaturated zone, the groundwater recharge, radionuclide transport, and seepage into the underground tunnels. Because net infiltration is largely affected by climatic conditions, future changes in climatic conditions will potentially alter net infiltration. The objectives of this presentation are to: (1) Present a conceptual model and a semi-empirical approach for regional, climatic forecasting of net infiltration, based on the precipitation and temperature data from analogue meteorological stations, and (2) Demonstrate the results of forecasting net infiltration for future climates--interglacial, monsoon and glacial--over the Yucca Mountain region for the period of 500,000 years. Calculations of the net infiltration were performed using a modified Budyko's water-balance model, for which potential evapotranspiration was evaluated from the temperature-based Thornthwaite formula. (Both Budyko's and Thornthwaite's formulae have been used broadly in hydrological studies.) The results of calculations were used for ranking net infiltration, along with the aridity and precipitation-effectiveness (P-E) indexes, for future climatic scenarios. Using this approach, we determined a general trend of increasing net infiltration from the present-day (interglacial) climate to monsoon, intermediate (glacial transition), and then to the glacial climate. Ranking of the aridity and P-E indexes is practically the same as that of net infiltration. The validation of the computed net infiltration rates yielded a good match with other field and modeling study results of groundwater recharge and net infiltration evaluation.

  17. Remediation to improve infiltration into compact soils.

    PubMed

    Olson, Nicholas C; Gulliver, John S; Nieber, John L; Kayhanian, Masoud

    2013-03-15

    Urban development usually involves soil compaction through converting large pervious land into developed land. This change typically increases runoff during runoff events and consequently may add to flooding and additional volume of runoff. The wash off of pollutants may also create numerous water quality and environmental problems for receiving waters. To alleviate this problem many municipalities are considering low impact development. One technique to reduce runoff in an urban area is to improve the soil infiltration. This study is specifically undertaken to investigate tilling and compost addition to improve infiltration rate, and to investigate measurement tools to assess the effectiveness of remediated soil. Soil remediation was performed at three sites in an urban area metropolitan area. Each site was divided into three plots: tilled, tilled with compost addition, and a control plot with no treatment. The infiltration effectiveness within each plot was assessed by measuring saturated hydraulic conductivity (K(sat)) using the modified Philip Dunne (MPD) infiltrometer during pre- and post-treatment. In addition, the use of soil bulk density and soil strength as surrogate parameters for K(sat) was investigated. Results showed that deep tillage was effective at reducing the level of soil strength. Soil strength was approximately half that of the control plot in the first six inches of soil. At two of the sites, tilling was also ineffective at improving the infiltration capacity of the soil. The geometric mean of K(sat) was 0.5-2.3 times that of the control plot, indicating little overall improvement. Compost addition was more effective than tilling by reducing the soil strength and compaction and increasing soil infiltration. The geometric mean of K(sat) on the compost plots was 2.7-5.7 times that of the control plot. No strong correlations were observed before remediation between either soil bulk density or soil strength and K(sat). Simulation results showed

  18. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    SciTech Connect

    Logue, J. M.; Turner, W. J.N.; Walker, I. S.; Singer, B. C.

    2015-07-01

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector’s energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level.

  19. A neural network based optimization system provides on-line coal fired furnace air flow balancing for heat rate improvement and NO{sub x} reduction

    SciTech Connect

    Radl, B.J.; Roland, W. Jr.

    1995-12-31

    The optimization system provides on-line, real-time air flow balancing without extensive testing or large complex physical models. NO{sub x} emissions and unit heat rate are very sensitive to air distribution and turbulence in the combustion zone. These issues are continuously changing due to ambient conditions, coal quality and the condition of plant equipment. This report discusses applying on-line, real-time and neural network to adjust secondary air flow and overfire air flow to reduce NO{sub x} and improve heat rate on various coal fired boiler designs.

  20. Oxidation rate of nuclear-grade graphite IG-110 in the kinetic regime for VHTR air ingress accident scenarios

    NASA Astrophysics Data System (ADS)

    Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

    2014-03-01

    The oxidation rates of nuclear-grade graphite IG-110 in the kinetically-controlled temperature regime of graphite oxidation were predicted and compared in Very High Temperature Reactor air ingress accident scenarios. The oxidative mass loss of graphite was measured thermogravimetrically from 873 to 1873 K in 100% air (21 mol%). The activation energy was found to be 222.07 kJ/mol, and the order of reaction with respect to oxygen concentration is 0.76. The surfaces of the samples were characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Fourier Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy before and after oxidation. These results are compared with those available in the literature, and our recently reported results for NBG-18 nuclear-grade graphite using the same technique.

  1. Relationships between ozone photolysis rates and peroxy radical concentrations in clean marine air over the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Penkett, S. A.; Monks, P. S.; Carpenter, L. J.; Clemitshaw, K. C.; Ayers, G. P.; Gillett, R. W.; Galbally, I. E.; Meyer, C. P.

    1997-06-01

    Measurements of the sum of inorganic and organic peroxy radicals (RO2) and photolysis rate coefficients J(NO2) and J(O1D) have been made at Cape Grim, Tasmania in the course of a comprehensive experiment which studied photochemistry in the unpolluted marine boundary layer. The SOAPEX (Southern Ocean Atmospheric Photochemistry Experiment) campaign included measurements of ozone, peroxides, nitrogen oxides, water vapor, and many other parameters. This first full length paper concerned with the experiment focuses on the types of relationships observed between peroxy radicals and J(NO2), J(O1D) and √[J(O1D)] in different air masses in which ozone is either produced or destroyed by photochemistry. It was found that in baseline air with ozone loss, RO2 was proportional to √[J(O1D)], whereas in more polluted air RO2 was proportional to J(O1D). Simple algorithms were derived to explain these relationships and also to calculate the concentrations of OH radicals in baseline air from the instantaneous RO2 concentrations. The signal to noise ratio of the peroxy radical measurements was up to 10 for 1-min values and much higher than in other previous deployments of the instrument in the northern hemisphere, leading to the confident determination of the relationships between RO2 and J(O1D) in different conditions. The absolute concentration Of RO2 determined in these experiments is in some doubt, but this does not affect our conclusions concerned either with the behavior of peroxy radicals with changing light levels or with the concentrations of OH calculated from RO2. The results provide confidence that the level of understanding of the photochemistry of ozone leading to the production of peroxide via recombination of peroxy radicals in clean air environments is well advanced.

  2. Crash Rates of Scheduled Commuter and Air Carrier Flights Before and After a Regulatory Change

    PubMed Central

    Baker, Susan P.; Groff, Loren; Haaland, Wren; Qiang, Yandong; Rebok, George W.; Li, Guohua

    2010-01-01

    Introduction In 1997, in an effort to reduce the crash rate of scheduled commuter flights, the FAA required aircraft with 10–30 passenger seats to operate under stricter rules. Training and other requirements of 14 CFR Part 121 rules were applied to these midsize commuters, which previously had operated under the less strict Part 135 rules. Published crash rates obscured changes related to aircraft size. This research was undertaken to determine whether the rule change affected crash rates of aircraft with 10–30 passenger seats. Method We determined the number of passenger seats on each Part 135 or Part 121 aircraft that crashed between 1983 and 2007. For aircraft with < 10, 10–30, and > 30 seats, we estimated the numbers of departures and crash rates, adjusting for changes in total departures and numbers of in-service aircraft. Results The Part 135 crash rate tripled in 1997 when commuters with 10–30 seats were excluded, reflecting the administrative change. However, the crash rate of aircraft with 10–30 passenger seats began to decline 4 yr before the rule change; thereafter, their rate was lower than for larger aircraft. The fleet size of aircraft with 10–30 passenger seats increased from 1983 to 1997, then declined as they were replaced with larger aircraft in response to the rule change. Discussion No effect of the rule change on crash rates of 10–30-seat aircraft was apparent. The decline in their crash rates began before the rule change and may have been related to the 1992 requirement for ground proximity warning devices. PMID:19378909

  3. Distribution and Rate of Microbial Processes in an Ammonia-Loaded Air Filter Biofilm▿

    PubMed Central

    Juhler, Susanne; Revsbech, Niels Peter; Schramm, Andreas; Herrmann, Martina; Ottosen, Lars D. M.; Nielsen, Lars Peter

    2009-01-01

    The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH3 in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet. Nitrite oxidation was not detected during most of the experimental period, and the AOB activity therefore resulted in NO2−, accumulation, with concentrations often exceeding 100 mM at the filter inlet. The restriction of AOB to the outlet section of the filter was explained by both competition with heterotrophic bacteria for O2 and inhibition by the protonated form of NO2−, HNO2. Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH3 concentration irrespective of variations in inlet concentration and airflow. PMID:19363071

  4. Anesthetic efficacy of infiltrations in mandibular anterior teeth.

    PubMed Central

    Yonchak, T.; Reader, A.; Beck, M.; Clark, K.; Meyers, W. J.

    2001-01-01

    The purpose of this prospective, randomized, double-blind study was to measure the degree of anesthesia obtained with a labial infiltration of either 2% lidocaine with 1:50,000 or 2% lidocaine with 1:100,000 epinephrine in mandibular anterior teeth. Another objective was to measure the degree of anesthesia obtained with a lingual infiltration of 2% lidocaine with 1:100,000 epinephrine in mandibular anterior teeth. Through use of a repeated-measures design, 40 subjects randomly received a labial infiltration at the lateral incisor apex of either 1.8 mL of 2% lidocaine with 1:100,000 epinephrine or 1.8 mL of 2% lidocaine with 1:50,000 epinephrine at 2 separate appointments. An additional 40 subjects received a lingual infiltration at the lateral incisor apex of 1.8 mL of 2% lidocaine with 1:100,000 epinephrine. The mandibular anterior teeth were blindly pulp tested at 4-minute cycles for 60 minutes postinjection. No response from the subject to the maximum output (80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when 2 consecutive 80 readings were obtained. For the 3 infiltrations, success rates for the lateral incisor ranged from 43 to 50%. Adjacent teeth had success rates of 27 to 63%. There was no significant difference (P > 0.05) in success between the labial infiltration of 2% lidocaine with 1:100,000 epinephrine and 2% lidocaine with 1:50,000 epinephrine or the lingual infiltration of 2% lidocaine with 1:100,000 epinephrine when compared with the labial infiltration of 2% lidocaine with 1:100,000 epinephrine. Duration of pulpal anesthesia declined steadily for all solutions over the 60 minutes. In conclusion, the success rate of 43-50% and declining duration of pulpal anesthesia over an hour indicates that a labial infiltration of 1.8 mL of either 2% lidocaine with 1:100,000 epinephrine or 1: 50,000 epinephrine or a lingual infiltration of 2% lidocaine with 1:100,000 epinephrine over the

  5. Low air exchange rate causes high indoor radon concentration in energy-efficient buildings.

    PubMed

    Vasilyev, A V; Yarmoshenko, I V; Zhukovsky, M V

    2015-06-01

    Since 1995, requirements on energy-efficient building construction were established in Russian Building Codes. In the course of time, utilisation of such technologies became prevailing, especially in multi-storey building construction. According to the results of radon survey in buildings constructed meeting new requirements on energy efficiency, radon concentration exceeds the average level in early-constructed buildings. Preponderance of the diffusion mechanism of radon entry in modern multi-storey buildings has been experimentally established. The experimental technique of the assessment of ventilation rate in dwellings under real conditions was developed. Based on estimates of average ventilation rate, it was approved that measures to increase energy efficiency lead to reduction in ventilation rate and accumulation of higher radon concentrations indoors. Obtained ventilation rate values have to be considered as extremely low.

  6. Embedded computer controlled premixing inline injection system for air-assisted variable-rate sprayers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvements to reduce chemical waste and environmental pollution for variable-rate sprayers used in orchards and ornamental nurseries require inline injection techniques. A microprocessor controlled premixing inline injection system implementing a ceramic piston chemical metering pump and two small...

  7. An accurate derivation of the air dose-rate and the deposition concentration distribution by aerial monitoring in a low level contaminated area

    NASA Astrophysics Data System (ADS)

    Nishizawa, Yukiyasu; Sugita, Takeshi; Sanada, Yukihisa; Torii, Tatsuo

    2015-04-01

    Since 2011, MEXT (Ministry of Education, Culture, Sports, Science and Technology, Japan) have been conducting aerial monitoring to investigate the distribution of radioactive cesium dispersed into the atmosphere after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), Tokyo Electric Power Company. Distribution maps of the air dose-rate at 1 m above the ground and the radioactive cesium deposition concentration on the ground are prepared using spectrum obtained by aerial monitoring. The radioactive cesium deposition is derived from its dose rate, which is calculated by excluding the dose rate of the background radiation due to natural radionuclides from the air dose-rate at 1 m above the ground. The first step of the current method of calculating the dose rate due to natural radionuclides is calculate the ratio of the total count rate of areas where no radioactive cesium is detected and the count rate of regions with energy levels of 1,400 keV or higher (BG-Index). Next, calculate the air dose rate of radioactive cesium by multiplying the BG-Index and the integrated count rate of 1,400 keV or higher for the area where the radioactive cesium is distributed. In high dose-rate areas, however, the count rate of the 1,365-keV peak of Cs-134, though small, is included in the integrated count rate of 1,400 keV or higher, which could cause an overestimation of the air dose rate of natural radionuclides. We developed a method for accurately evaluating the distribution maps of natural air dose-rate by excluding the effect of radioactive cesium, even in contaminated areas, and obtained the accurate air dose-rate map attributed the radioactive cesium deposition on the ground. Furthermore, the natural dose-rate distribution throughout Japan has been obtained by this method.

  8. The effects of air temperature on office workers' well-being, workload and productivity-evaluated with subjective ratings.

    PubMed

    Lan, Li; Lian, Zhiwei; Pan, Li

    2010-12-01

    Productivity bears a close relationship to the indoor environmental quality (IEQ), but how to evaluate office worker's productivity remains to be a challenge for ergonomists. In this study, the effect of indoor air temperature (17 °C, 21 °C, and 28 °C) on productivity was investigated with 21 volunteered participants in the laboratory experiment. Participants performed computerized neurobehavioral tests during exposure in the lab; their physiological parameters including heart rate variation (HRV) and electroencephalograph (EEG) were also measured. Several subjective rating scales were used to tap participant's emotion, well-being, motivation and the workload imposed by tasks. It was found that the warm discomfort negatively affected participants' well-being and increased the ratio of low frequency (LF) to high frequency (HF) of HRV. In the moderately uncomfortable environment, the workload imposed by tasks increased and participants had to exert more effort to maintain their performance and they also had lower motivation to do work. The results indicate that thermal discomfort caused by high or low air temperature had negative influence on office workers' productivity and the subjective rating scales were useful supplements of neurobehavioral performance measures when evaluating the effects of IEQ on productivity.

  9. Indoor air quality, air exchange rates, and radioactivity in new built temporary houses following the Great East Japan Earthquake in Minamisoma, Fukushima.

    PubMed

    Shinohara, N; Tokumura, M; Kazama, M; Yoshino, H; Ochiai, S; Mizukoshi, A

    2013-08-01

    This study measured air exchange rates, indoor concentrations of aldehydes and volatile organic compounds (VOCs), and radioactivity levels at 19 temporary houses in different temporary housing estate constructed in Minamisoma City following the Great East Japan Earthquake. The 19 surveyed houses represented all of the companies assigned to construct temporary houses in that Minamisoma City. Data were collected shortly after construction and before occupation, from August 2011 to January 2012. Mean air exchange rates in the temporary houses were 0.28/h, with no variation according to housing types and construction date. Mean indoor concentrations of formaldehyde, acetaldehyde, toluene, ethylbenzene, m/p-xylene, o-xylene, styrene, p-dichlorobenzene, tetradecane, and total VOCs (TVOCs) were 29.2, 72.7, 14.6, 6.35, 3.05, 1.81, 7.29, 14.3, 8.32, and 901 μg/m(3), respectively. The levels of acetaldehyde and TVOCs exceeded the indoor guideline (48 μg/m(3)) and interim target (400 μg/m(3)) in more than half of the 31 rooms tested. In addition to guideline chemicals, terpenes (α-pinene and d-limonene) and acetic esters (butyl acetate and ethyl acetate) were often detected in these houses. The indoor radiation levels measured by a Geiger-Müller tube (Mean: 0.22 μSv/h) were lower than those recorded outdoors (Mean: 0.42 μSv/h), although the shielding effect of the houses was less than for other types of buildings.

  10. Methods to Use Surface Infiltration Tests in Permeable Pavement Systems to Determine Maintenance Frequency

    EPA Science Inventory

    Currently, there is limited guidance on selecting test sites to measure surface infiltration rates in permeable pavement systems to determine maintenance frequency. The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete suggest to either (1) p...

  11. Effect of liquid distribution on gas-water phase mass transfer in an unsaturated sand during infiltration

    NASA Astrophysics Data System (ADS)

    Imhoff, Paul T.; Jaffé, Peter R.

    1994-09-01

    Gas-water phase mass transfer was examined in a homogeneous sand with both the gas and water phase mobile: water was infiltrated from the top of the sand column while benzene-laden air flowed upward from the bottom. Mass-transfer limitations for this situation may be important for applications of bioventing, where water and nutrients are added at the ground surface simultaneously with induced air movement to carry oxygen and volatile organics to microbial populations. Gas- and water-phase samples indicate that gas-water phase mass transfer was sufficiently fast that equilibrium between gas and water phases was achieved at all sampling locations within the porous medium. Lower-bound estimates for the gas-water mass-transfer rate coefficient show that mass transfer was at least 10-40 times larger than predictions made from an empirical model developed for gas-water phase mass transfer in an identical porous medium. A water-phase tracer test demonstrates that water flow was much more uniform in this study than in those earlier experiments, which is a likely explanation for the differing rates of gas-water phase mass transfer. It is hypothesized that the liquid distribution in previous laboratory experiments was less uniform because of preferential flow paths due to wetting front instabilities. Gas-water phase mass-transfer rate coefficients reported in this investigation are for an ideal situation of uniform water infiltration: mass-transfer rates in field soils are expected to be significantly smaller.

  12. Improving snow process modeling with satellite-based estimation of near-surface-air-temperature lapse rate

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Sun, Litao; Shrestha, Maheswor; Li, Xiuping; Liu, Wenbin; Zhou, Jing; Yang, Kun; Lu, Hui; Chen, Deliang

    2016-10-01

    In distributed hydrological modeling, surface air temperature (Tair) is of great importance in simulating cold region processes, while the near-surface-air-temperature lapse rate (NLR) is crucial to prepare Tair (when interpolating Tair from site observations to model grids). In this study, a distributed biosphere hydrological model with improved snow physics (WEB-DHM-S) was rigorously evaluated in a typical cold, large river basin (e.g., the upper Yellow River basin), given a mean monthly NLRs. Based on the validated model, we have examined the influence of the NLR on the simulated snow processes and streamflows. We found that the NLR has a large effect on the simulated streamflows, with a maximum difference of greater than 24% among the various scenarios for NLRs considered. To supplement the insufficient number of monitoring sites for near-surface-air-temperature at developing/undeveloped mountain regions, the nighttime Moderate Resolution Imaging Spectroradiometer land surface temperature is used as an alternative to derive the approximate NLR at a finer spatial scale (e.g., at different elevation bands, different land covers, different aspects, and different snow conditions). Using satellite-based estimation of NLR, the modeling of snow processes has been greatly refined. Results show that both the determination of rainfall/snowfall and the snowpack process were significantly improved, contributing to a reduced summer evapotranspiration and thus an improved streamflow simulation.

  13. Development of a two-step, forced chemical vapor infiltration process

    SciTech Connect

    Matlin, W.M.; Stinton, D.P.; Besmann, T.M.

    1995-12-01

    A two-step forced chemical vapor infiltration process was developed that reduced infiltration times for 4.45 cm dia. by 1.27 cm thick Nicalon{trademark} fiber pre-forms by two thirds while maintaining final densities near 90%. In the first stage of the process, micro-voids within fiber bundles in the cloth were uniformly infiltrated throughout the preform. In the second stage, the deposition rate was increased to more rapidly fill the macro-voids between bundles within the cloth and between layers of cloth. By varying the thermal gradient across the preform uniform infiltration rates were maintained and high final densities achieved.

  14. Net-Infiltration map of the Navajo Sandstone outcrop area in western Washington County, Utah

    USGS Publications Warehouse

    Heilweil, Victor M.; McKinney, Tim S.

    2007-01-01

    As populations grow in the arid southwestern United States and desert bedrock aquifers are increasingly targeted for future development, understanding and quantifying the spatial variability of net infiltration and recharge becomes critically important for inventorying groundwater resources and mapping contamination vulnerability. A Geographic Information System (GIS)-based model utilizing readily available soils, topographic, precipitation, and outcrop data has been developed for predicting net infiltration to exposed and soil-covered areas of the Navajo Sandstone outcrop of southwestern Utah. The Navajo Sandstone is an important regional bedrock aquifer. The GIS model determines the net-infiltration percentage of precipitation by using an empirical equation. This relation is derived from least squares linear regression between three surficial parameters (soil coarseness, topographic slope, and downgradient distance from outcrop) and the percentage of estimated net infiltration based on environmental tracer data from excavations and boreholes at Sand Hollow Reservoir in the southeastern part of the study area.Processed GIS raster layers are applied as parameters in the empirical equation for determining net infiltration for soil-covered areas as a percentage of precipitation. This net-infiltration percentage is multiplied by average annual Parameter-elevation Regressions on Independent Slopes Model (PRISM) precipitation data to obtain an infiltration rate for each model cell. Additionally, net infiltration on exposed outcrop areas is set to 10 percent of precipitation on the basis of borehole net-infiltration estimates. Soils and outcrop net-infiltration rates are merged to form a final map.Areas of low, medium, and high potential for ground-water recharge have been identified, and estimates of net infiltration range from 0.1 to 66 millimeters per year (mm/yr). Estimated net-infiltration rates of less than 10 mm/yr are considered low, rates of 10 to 50 mm/yr are

  15. Oxidation rate of graphitic matrix material in the kinetic regime for VHTR air ingress accident scenarios

    NASA Astrophysics Data System (ADS)

    Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

    2014-08-01

    Data on oxidation rates of matrix-grade graphite in the kinetically-controlled temperature regime of graphite oxidation are needed for safety analysis of High Temperature Gas Cooled Reactors and Very High Temperature Reactors. In this work, the oxidation rate of graphitic matrix material GKrS was measured thermogravimetrically for various oxygen concentrations and with temperatures from 873 to 1873 K. A semi-empirical Arrhenius rate equation was also developed for this temperature range. The activation energy of the graphitic material is found to be about 111.5 kJ/mol. The order of reaction was found to be about 0.89. The surface of oxidized GKrS was characterized by Scanning Electron Microscopy, Electron Dispersive Spectroscopy, Fourier Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy.

  16. GROUND WATER CONTAMINATION POTENTIAL FROM STORMWATER INFILTRATION

    EPA Science Inventory

    Prior to urbanization, ground water recharge resulted from infiltration of precipitation through pervious surfaces, including grasslands and woods. This infiltration water was relatively uncontaminated. With urbanization, the permeable soil surface area through which recharge by...

  17. Air Change Rates and Interzonal Flows in Residences, and the Need for Multi-Zone Models for Exposure and Health Analysis

    EPA Science Inventory

    Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measureme...

  18. Runoff production on a slope with randomly distributed infiltrabilities

    NASA Astrophysics Data System (ADS)

    Mouche, E.; Harel, M.

    2013-12-01

    Runoff generated on one- and two-dimensional slopes with randomly distributed infiltrability is studied in the queuing theory and connectivity frameworks. The equivalence between the runoff-runon equation and the customers waiting time in a single server queue provides a theoretical link between the statistical descriptions of infiltrability and that of runoff flow rate. Different distributions of infiltrability, representing soil heterogeneities at different scales, are considered. Numerical simulations validate these results and improve our understanding of runoff-runon process. All of the quantities describing the generation of runoff (runoff one-point statistics) and its organization into patterns (patterns statistics and connectivity) are studied as functions of rainfall rate and runoff dimensionality.

  19. Relationships between Individual Differences and Accuracy in Rating Air Force Jet Engine Mechanic Performance

    DTIC Science & Technology

    1989-08-01

    may be enhanced to some extent (Thornton & Zorich , 1980). However, training costs may still be reduced by selecting for training those candidates with...ratee behaviors correctly noted by the rater (Thornton & Zorich , 1980). Several studies have investigated evaluation accuracy. For example, Borman (1977...correlations: Uses in assessing rater reliability. Psychological Bulletin, 86, 420-428. Thornton, G., & Zorich , S. (1980). Training to improve

  20. Monitoring the impact of the indoor air quality on silver cultural heritage objects using passive and continuous corrosion rate assessments

    NASA Astrophysics Data System (ADS)

    `t Hart, Lucy; Storme, Patrick; Anaf, Willemien; Nuyts, Gert; Vanmeert, Frederik; Dorriné, Walter; Janssens, Koen; de Wael, Karolien; Schalm, Olivier

    2016-10-01

    There is a long tradition in evaluating industrial atmospheres by measuring the corrosion rate of exposed metal coupons. The heritage community also uses this method, but the interpretation of the corrosion rate often lacks clarity due to the low corrosivity in indoor museum environments. This investigation explores the possibilities and drawbacks of different silver corrosion rate assessments. The corrosion rate is determined by three approaches: (1) chemical characterization of metal coupons using analytical techniques such as electrochemical measurements, SEM-EDX, XRD, and µ-Raman spectroscopy, (2) continuous corrosion monitoring methods based on electrical resistivity loss of a corroding nm-sized metal wire and weight gain of a corroding silver coated quartz crystal, and (3) characterization of the visual degradation of the metal coupons. This study confirms that subtle differences in corrosivity between locations inside a museum can be determined on condition that the same corrosion rate assessment is used. However, the impact of the coupon orientation with respect to the prevailing direction of air circulation can be substantially larger than the impact of the coupon location.

  1. [Characters of infiltration and preferential flow of black soil in Northeast China under different tillage patterns].

    PubMed

    Li, Wen-Feng; Zhang, Xiao-Ping; Liang, Ai-Zhen; Shen, Yan; Shi, Xiu-Huan; Luo, Jin-Ming; Yang, Xue-Ming

    2008-07-01

    By using dye tracer and double-ring infiltrometer techniques, the characters of infiltration and preferential flow of black soil under no-tillage (NT) and fall moldboard plow (MP) were compared after six years continuous management. The results showed that the infiltration rate was higher under NT than under MP. When the infiltration reached steady, the infiltration rate and accumulative infiltration capacity under NT were 1.35 and 1.44 times as high as those under MP, respectively. The penetration depth of methylene blue reached a depth of 43 cm in NT soil, being 16 cm deeper than that in MP soil. Comparing with MP soil, NT soil had better development of pore structure and more biological pores, and presented better preferential flow character, which were of importance for water infiltration and soil and water conservation.

  2. SENSOR FOR INDIVIDUAL BURNER CONTROL OF FIRING RATE, FUEL-AIR RATIO, AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill; Roger Demler; Robert G. Mudry

    2004-10-01

    Instrumentation difficulties encountered in the previous reporting period were addressed early in this reporting period, resulting in a new instrumentation configuration that appears to be free of the noise issues found previously. This permitted the collection of flow calibration data to begin. The first issues in question are the effects of the type and location of the transducer mount. Data were collected for 15 different transducer positions (upstream and downstream of an elbow in the pipe), with both a stud mount and a magnetic transducer mount, for each of seven combinations of air and coal flow. Analysis of these data shows that the effects of the transducer mount type and location on the resulting dynamics are complicated, and not easily captured in a single analysis. To maximize the practical value of the calibration data, further detailed calibration data will be collected with both the magnetic and stud mounts, but at a single mounting location just downstream of a pipe elbow. This testing will be performed in the Coal Flow Test Facility in the next reporting period. The program progress in this reporting period was sufficient to put us essentially back on schedule.

  3. Gas phase dispersion in compost as a function of different water contents and air flow rates.

    PubMed

    Sharma, Prabhakar; Poulsen, Tjalfe G

    2009-07-21

    Gas phase dispersion in a natural porous medium (yard waste compost) was investigated as a function of gas flow velocity and compost volumetric water content using oxygen and nitrogen as tracer gases. The compost was chosen because it has a very wide water content range and because it represents a wide range of porous media, including soils and biofilter media. Column breakthrough curves for oxygen and nitrogen were measured at relatively low pore gas velocities, corresponding to those observed in for instance soil vapor extraction systems or biofilters for air cleaning at biogas plants or composting facilities. Total gas mechanical dispersion-molecular diffusion coefficients were fitted from the breakthrough curves using a one-dimensional numerical solution to the advection-dispersion equation and used to determine gas dispersivities at different volumetric gas contents. The results showed that gas mechanical dispersion dominated over molecular diffusion with mechanical dispersion for all water contents and pore gas velocities investigated. Importance of mechanical dispersion increased with increasing pore gas velocity and compost water content. The results further showed that gas dispersivity was relatively constant at high values of compost gas-filled porosity but increased with decreasing gas-filled porosity at lower values of gas-filled porosity. Results finally showed that measurement uncertainty in gas dispersivity is generally highest at low values of pore gas velocity.

  4. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    PubMed Central

    2012-01-01

    The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream. PMID:23369487

  5. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower.

    PubMed

    Jafari, Mohammad Javad; Ghasemi, Roohollah; Mehrabi, Yadollah; Yazdanbakhsh, Ahmad Reza; Hajibabaei, Majid

    2012-12-10

    The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2-3 and further to 80.2% at L/G of >3, respectively. L/G of 2-3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.

  6. A multiscale Bayesian data integration approach for mapping air dose rates around the Fukushima Daiichi Nuclear Power Plant.

    PubMed

    Wainwright, Haruko M; Seki, Akiyuki; Chen, Jinsong; Saito, Kimiaki

    2017-02-01

    This paper presents a multiscale data integration method to estimate the spatial distribution of air dose rates in the regional scale around the Fukushima Daiichi Nuclear Power Plant. We integrate various types of datasets, such as ground-based walk and car surveys, and airborne surveys, all of which have different scales, resolutions, spatial coverage, and accuracy. This method is based on geostatistics to represent spatial heterogeneous structures, and also on Bayesian hierarchical models to integrate multiscale, multi-type datasets in a consistent manner. The Bayesian method allows us to quantify the uncertainty in the estimates, and to provide the confidence intervals that are critical for robust decision-making. Although this approach is primarily data-driven, it has great flexibility to include mechanistic models for representing radiation transport or other complex correlations. We demonstrate our approach using three types of datasets collected at the same time over Fukushima City in Japan: (1) coarse-resolution airborne surveys covering the entire area, (2) car surveys along major roads, and (3) walk surveys in multiple neighborhoods. Results show that the method can successfully integrate three types of datasets and create an integrated map (including the confidence intervals) of air dose rates over the domain in high resolution. Moreover, this study provides us with various insights into the characteristics of each dataset, as well as radiocaesium distribution. In particular, the urban areas show high heterogeneity in the contaminant distribution due to human activities as well as large discrepancy among different surveys due to such heterogeneity.

  7. Properties of the seawater-air interface. 2. Rates of surface film formation under steady state conditions

    SciTech Connect

    Dragcevic, D.; Pravdic, V.

    1981-05-01

    The laboratory techniques of dynamic surface tension and of surface electrical potential measurements were used to determine rates of formation and of reorientation of organic surface films at the seawater-air interface. Relaxation times of surface films were determined for three characteristic samples obtained by screen and bottle sampling in the coastal waters of the northern Adriatic area. These data were compared with those for model samples produced by spreading oleic acid and crude oil on or dissolving polyethyleneglycol and sodium dodecyl sulfate in artificial seawater. Relaxation times were in the range of 0.1-1 s for most of the samples. A good representative value for field samples is 0.2 s. The temperature-dependence (the energies of activation) for the surface film relaxation indicates that several processes control material transport toward the seawater-air interface. The findings are interpreted as showing that an almost ever-present organic surface film influences the mechanism and the rate of material transport across the sea-atmosphere boundary.

  8. Particulate Air Pollution and the Rate of Hospitalization for Congestive Heart Failure among Medicare Beneficiaries in Pittsburgh, Pennsylvania.

    PubMed Central

    Wellenius, Gregory A.; Bateson, Thomas F.; Mittleman, Murray A.; Schwartz., Joel

    2006-01-01

    We used a case-crossover approach to evaluate the association between ambient air pollution and the rate of hospitalization for congestive heart failure (CHF) among Medicare recipients (age ≥ 65) residing in Allegheny County (Pittsburgh area), PA, during 1987–1999. We also explored effect modification by age, gender, and specific secondary diagnoses. During follow-up, there were 55,019 admissions with a primary diagnosis of CHF. We found that particulate matter with aerodynamic diameter ≤ 10 μm (PM10), carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide – but not ozone – were positively and significantly associated with the rate of admission on the same day in single-pollutant models. The strongest associations were observed with CO, NO2 and PM10. The associations with CO and NO2 were the most robust in two-pollutant models, remaining statistically significant even after adjusting for other pollutants. Patients with a recent myocardial infarction were at greater risk of particulate-related admission, but there was otherwise no significant effect modification by age, gender, or other secondary diagnoses. These results suggest that short-term elevations in air pollution from traffic-related sources may trigger acute cardiac decompensation of heart failure patients and that those with certain comorbid conditions may be more susceptible to these effects. PMID:15901623

  9. Oxidation and decomposition mechanisms of air sensitive aluminum clusters at high heating rates

    NASA Astrophysics Data System (ADS)

    DeLisio, Jeffery B.; Mayo, Dennis H.; Guerieri, Philip M.; DeCarlo, Samantha; Ives, Ross; Bowen, Kit; Eichhorn, Bryan W.; Zachariah, Michael R.

    2016-09-01

    Molecular near zero oxidation state clusters of metals are of interest as fuel additives. In this work high heating rate decomposition of the Al(I) tetrameric cluster, [AlBr(NEt3)]4 (Et = C2H5), was studied at heating rates of up to 5 × 105 K/s using temperature-jump time-of-flight mass spectrometry (T-jump TOFMS). Gas phase Al and AlHx species were rapidly released during decomposition of the cluster, at ∼220 °C. The activation energy for decomposition was determined to be ∼43 kJ/mol. Addition of an oxidizer, KIO4, increased Al, AlO, and HBr signal intensities, showing direct oxidation of the cluster with gas phase oxygen.

  10. Development of a Portable Gamma-ray Survey System for the Measurement of Air Dose Rates

    NASA Astrophysics Data System (ADS)

    Goto, Jun; Shobugawa, Yugo; Kawano, Yoh; Amaya, Yoshihiro; Izumikawa, Takuji; Katsuragi, Yoshinori; Shiiya, Tomohiro; Suzuki, Tsubasa; Takahashi, Takeshi; Takahashi, Toshihiro; Yoshida, Hidenori; Naito, Makoto

    BIo-Safety Hybrid Automatic MOnitor-Niigata (BISHAMON), a portable gamma-ray survey system, was developed to support victims of the Fukushima Daiichi nuclear disaster. BISHAMON is capable of constructing a map of the distribution of ambient dose equivalent rates using vehicle-mounted or on-foot survey methods. In this study, we give an overview of BISHAMON and its measurement results including a comparison with those of other systems such as KURAMA.

  11. Effect of ventilation systems and air filters on decay rates of particles produced by indoor sources in an occupied townhouse

    NASA Astrophysics Data System (ADS)

    Howard-Reed, Cynthia; Wallace, Lance A.; Emmerich, Steven J.

    Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we measured the deposition of particles ranging from 0.3 to 10 μm in an occupied townhouse and also in an unoccupied test house. Experiments were run with three different sources (cooking with a gas stove, citronella candle, pouring kitty litter), with the central heating and air conditioning (HAC) fan on or off, and with two different types of in-duct filters (electrostatic precipitator and ordinary furnace filter). Particle size, HAC fan operation, and the electrostatic precipitator had significant effects on particle loss rates. The standard furnace filter had no effect. Surprisingly, the type of source (combustion vs. mechanical generation) and the type of furnishings (fully furnished including carpet vs. largely unfurnished including mostly bare floor) also had no measurable effect on the deposition rates of particles of comparable size. With the HAC fan off, average deposition rates varied from 0.3 h -1 for the smallest particle range (0.3-0.5 μm) to 5.2 h -1 for particles greater than 10 μm. Operation of the central HAC fan approximately doubled these rates for particles <5 μm, and increased rates by 2 h -1 for the larger particles. An in-duct electrostatic precipitator increased the loss rates compared to the fan-off condition by factors of 5-10 for particles <2.5 μm, and by a factor of 3 for 2.5-5.0 μm particles. In practical terms, use of the central fan alone could reduce indoor particle concentrations by 25-50%, and use of an in-duct ESP could reduce particle concentrations by 55-85% compared to fan-off conditions.

  12. Determining the extent of groundwater interference on the performance of infiltration trenches

    NASA Astrophysics Data System (ADS)

    Locatelli, Luca; Mark, Ole; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten; Wong, Tony; Binning, Philip John

    2015-10-01

    Infiltration trenches are widely used in stormwater management, but their capacity decreases when installed in areas with shallow groundwater where infiltration is limited by groundwater drainage. Here the hydrological performance of single infiltration trenches in areas with shallow water tables is quantified in terms of their capability to reduce peak flow, peak volume and annual stormwater runoff volume. To simulate the long term hydrological performance of infiltration trenches two different models are employed. The models continuously simulate infiltration rates from infiltration trenches using a 19 year rainfall time series from Copenhagen as input. The annual and single event stormwater runoff reduction from infiltration trenches was determined for 9 different scenarios that covered different soil conditions and infiltration trench dimensions. Monte Carlo simulations were used in order to quantify the impact of parameter variability for each scenario. Statistical analysis of the continuous long term model simulations was used to quantify the hydrological performance of infiltration trenches. Results show that infiltration trenches are affected by groundwater when there is an unsaturated depth of less than 1.5-3 m in sandy loam, 6.5-8 m in silt loam and 11-12 m in silty clay loam. A correction factor that can be applied for infiltration trench design when there is a shallow groundwater table is presented. The analyses showed that below a certain value of unsaturated depth the dissipation capacity of the mound/groundwater becomes the dominant process determining the infiltration capacity from infiltration trenches. In these cases it is essential to consider the local groundwater conditions in the infiltration trench design process.

  13. Field measurement of ventilation rates.

    PubMed

    Persily, A K

    2016-02-01

    Ventilation rates have significant impacts on building energy use and indoor contaminant concentrations, making them key parameters in building performance. Ventilation rates have been measured in buildings for many decades, and there are mature measurement approaches available to researchers and others who need to know actual ventilation rates in buildings. Despite the fact that ventilation rates are critical in interpreting indoor concentration measurements, it is disconcerting how few Indoor Air Quality field studies measure ventilation rates or otherwise characterize the ventilation design of the study building(s). This paper summarizes parameters of interest in characterizing building ventilation, available methods for quantifying these parameters, and challenges in applying these methods to different types of buildings and ventilation systems. These parameters include whole-building air change rates, system outdoor air intake rates, and building infiltration rates. Tracer gas methods are reviewed as well as system airflow rate measurements using, for example, duct traverses. Several field studies of ventilation rates conducted over the past 75 years are described to highlight the approaches employed and the findings obtained.

  14. Use of reference chemicals to determine passive uptake rates of common indoor air VOCs by collocation deployment of active and passive samplers.

    PubMed

    Xian, Qiming; Feng, Yong-Lai; Chan, Cecilia C; Zhu, Jiping

    2011-09-01

    Passive samplers have become more popular in their application in the measurement of airborne chemicals. For volatile organic compounds, the rate of a chemical's diffusivity is a determining factor in the quantity of the chemical being collected for a given passive sampler. While uptake rate of a chemical in the passive sampler can be determined either by collocation deployment of both active and passive samplers or use of controlled facilities such as environmental chambers, a new approach without a need for accurate active flow rate in the collocation experiment was demonstrated in this study. This approach uses chemicals of known uptake rates as references to calculate the actual flow rate of the active sampling in the collocation experiment. The active sampling rate in turn can be used in the determination of the uptake rates of all other chemicals present in the passive samplers. The advantage of such approach is the elimination of the errors in actual active sampling rate associated with low flow employed in the collocation experiment. Using this approach, passive uptake rates of more than 80 volatile organic compounds commonly present in indoor air were determined. These experimentally determined uptake rates correlate well with air diffusivity of the chemicals, indicating the regression equation describing such correlation might be useful in predicting the uptake rates of other volatile organic chemicals in indoor air based on their air diffusivity.

  15. Measurement of air dose rates over a wide area around the Fukushima Dai-ichi Nuclear Power Plant through a series of car-borne surveys.

    PubMed

    Andoh, Masaki; Nakahara, Yukio; Tsuda, Shuichi; Yoshida, Tadayoshi; Matsuda, Norihiro; Takahashi, Fumiaki; Mikami, Satoshi; Kinouchi, Nobuyuki; Sato, Tetsuro; Tanigaki, Minoru; Takamiya, Koichi; Sato, Nobuhiro; Okumura, Ryo; Uchihori, Yukio; Saito, Kimiaki

    2015-01-01

    A series of car-borne surveys using the Kyoto University RAdiation MApping (KURAMA) and KURAMA-II survey systems has been conducted over a wide area in eastern Japan since June 2011 to evaluate the distribution of air dose rates around the Fukushima Dai-ichi Nuclear Power Plant and to evaluate the time-dependent trend of decrease in air dose rates. An automated data processing system for the KURAMA-II system was established, which enabled rapid analysis of large amounts of data obtained using about 100 KURAMA-II units. The initial data used for evaluating the migration status of radioactive cesium were obtained in the first survey, followed by other car-borne surveys conducted over more extensive and wider measurement ranges. By comparing the measured air dose rates obtained in each survey (until December 2012), the decreasing trend of air dose rates measured through car-borne surveys was found to be more pronounced than those expected on the basis of the physical decay of radioactive cesium and of the air dose rates measured using NaI (Tl) survey meters in the areas surrounding the roadways. In addition, it was found that the extent of decrease in air dose rates depended on land use, wherein it decreased faster for land used as building sites than for forested areas.

  16. Two-step infiltration of aluminum melts into Al-Ti-B4C-CuO powder mixture pellets

    NASA Astrophysics Data System (ADS)

    Zhang, Jingjing; Lee, Jung-Moo; Cho, Young-Hee; Kim, Su-Hyeon; Yu, Huashun

    2016-03-01

    Aluminum matrix composites with a high volume fraction of B4C and TiB2 were fabricated by a novel processing technique - a quick spontaneous infiltration process. The process combines a pressureless infiltration with the combustion reaction of Al-Ti-B4C-CuO in molten aluminum. The process is realized in a simple and economical way in which the whole process is performed in air in a few minutes. To verify the rapidity of the process, the infiltration kinetics was calculated based on the Washburn equation in which melt flows into a porous skeleton. However, there was a noticeable deviation from the calculated results with the experimental results. Considering the cross-sections of the samples at different processing times, a new infiltration model (two step infiltration) consisting of macro-infiltration and micro-infiltration is suggested. The calculated kinetics results in light of the proposed model agree well with the experimental results.

  17. A Novel Method for Quantifying the Inhaled Dose of Air Pollutants Based on Heart Rate, Breathing Rate and Forced Vital Capacity

    PubMed Central

    Greenwald, Roby; Hayat, Matthew J.; Barton, Jerusha; Lopukhin, Anastasia

    2016-01-01

    To better understand the interaction of physical activity and air pollution exposure, it is important to quantify the change in ventilation rate incurred by activity. In this paper, we describe a method for estimating ventilation using easily-measured variables such as heart rate (HR), breathing rate (fB), and forced vital capacity (FVC). We recruited healthy adolescents to use a treadmill while we continuously measured HR, fB, and the tidal volume (VT) of each breath. Participants began at rest then walked and ran at increasing speed until HR was 160–180 beats per minute followed by a cool down period. The novel feature of this method is that minute ventilation (V˙E) was normalized by FVC. We used general linear mixed models with a random effect for subject and identified nine potential predictor variables that influence either V˙E or FVC. We assessed predictive performance with a five-fold cross-validation procedure. We used a brute force selection process to identify the best performing models based on cross-validation percent error, the Akaike Information Criterion and the p-value of parameter estimates. We found a two-predictor model including HR and fB to have the best predictive performance (V˙E/FVC = -4.247+0.0595HR+0.226fB, mean percent error = 8.1±29%); however, given the ubiquity of HR measurements, a one-predictor model including HR may also be useful (V˙E/FVC = -3.859+0.101HR, mean percent error = 11.3±36%). PMID:26809066

  18. SCC Propagation Rate of Type 304, 304L Steels Under Oceanic Air Environment

    SciTech Connect

    Akio Kosaki

    2006-07-01

    Corrosion integrity of canister in the concrete cask for spent fuel storage is very important because the canister serves to maintain the sealability over the storage period of 40 to 60 years. Natural exposure and accelerated corrosion tests of conventional stainless steels for canister, that are Type 304, 304L, and 316(LN), for concrete cask's canister have been conducted by using many three Point Bending (3PB) test specimens and compared. The SCC propagation rates in Type 304 and 304L at the natural condition were about 1.2 E-12 to 1.8 E-11 m/s at the K (Stress Intensity Factor) range of 0.6 to 9.0 MPa/m, and that of the accelerate test (60 degrees C, 95%RHS., filled with NaCl mist.) were about 1.0 E-10 to 3.5 E-9 m/s at the K range of 0.3 to 32 MPa/m. The SCC propagation rates under both natural and accelerated conditions were independent with K. Both da/dt values of the direct exposure test and of the under glass exposure test were in the same scattering band. (author)

  19. Air pollution and mortality rates: a note on Lave and Seskin's pooling of cross-section and time-series data

    SciTech Connect

    Christainsen, G.B.; Degen, C.G.

    1980-06-01

    Air Pollution and Human Health (Johns Hopkins University Press, Baltimore, 1977) by Lester Lave and Eugene Seskin reports the results of regressions which suggest a strong association between air pollution and mortality rates. This note questions assumptions made by Lave and Seskin which underlie their estimation of a single-equation model using pooled cross-section and time-series data. If, in fact, these assumptions cannot be made, the association between air pollution and mortality rates appears considerably weakened, but it still appears to be significant.

  20. Critical effect of pore characteristics on capillary infiltration in mesoporous films

    NASA Astrophysics Data System (ADS)

    Ceratti, D. R.; Faustini, M.; Sinturel, C.; Vayer, M.; Dahirel, V.; Jardat, M.; Grosso, D.

    2015-03-01

    Capillary phenomena governing the mass-transport (capillary filling, condensation/evaporation) has been experimentally investigated in around 20 different silica thin films exhibiting various porosities with pores dimension ranging from 2 to 200 nm. Films have been prepared by sol-gel chemistry combined with soft-templating approaches and controlled dip coating process. Environmental ellipsometric porosimetry combined with electronic microscopy were used to assess the porosity characteristics. Investigation of lateral capillary filling was performed by following the natural infiltration of water and ionic liquids at the edge of a sessile drop in open air or underneath a PDMS cover. The Washburn model was applied to the displacement of the liquid front within the films to deduce the kinetic constants. The role of the different capillary phenomena were discussed with respect to the porosity characteristics (porosity vol%, pore dimensions and constrictions). We show that correlation between capillary filling rate and pore dimensions is not straightforward. Generally, with a minimum of constrictions, faster filling is observed for larger pores. In the case of mesopores (<50 nm in diameter), the presence of bottle necks considerably slows down the infiltration rate. At such a small dimension, evaporation/capillary condensation dynamics, taking place at the meniscus inside the porosity, has to be considered to explain the transport mode. This fundamental study is of interest for applications involving liquids at the interface of mesoporous networks such as nanofluidics, purification, separation, water harvesting or heat transfer.

  1. Variably-saturated groundwater modeling for optimizing managed aquifer recharge using trench infiltration

    USGS Publications Warehouse

    Heilweil, Victor M.; Benoit, Jerome; Healy, Richard W.

    2015-01-01

    Spreading-basin methods have resulted in more than 130 million cubic meters of recharge to the unconfined Navajo Sandstone of southern Utah in the past decade, but infiltration rates have slowed in recent years because of reduced hydraulic gradients and clogging. Trench infiltration is a promising alternative technique for increasing recharge and minimizing evaporation. This paper uses a variably saturated flow model to further investigate the relative importance of the following variables on rates of trench infiltration to unconfined aquifers: saturated hydraulic conductivity, trench spacing and dimensions, initial water-table depth, alternate wet/dry periods, and number of parallel trenches. Modeling results showed (1) increased infiltration with higher hydraulic conductivity, deeper initial water tables, and larger spacing between parallel trenches, (2) deeper or wider trenches do not substantially increase infiltration, (3) alternating wet/dry periods result in less overall infiltration than keeping the trenches continuously full, and (4) larger numbers of parallel trenches within a fixed area increases infiltration but with a diminishing effect as trench spacing becomes tighter. An empirical equation for estimating expected trench infiltration rates as a function of hydraulic conductivity and initial water-table depth was derived and can be used for evaluating feasibility of trench infiltration in other hydrogeologic settings

  2. Gas exchange rates across the sediment-water and air-water interfaces in south San Francisco Bay

    USGS Publications Warehouse

    Hartman, Blayne; Hammond, Douglas E.

    1984-01-01

    Radon 222 concentrations in the water and sedimentary columns and radon exchange rates across the sediment-water and air-water interfaces have been measured in a section of south San Francisco Bay. Two independent methods have been used to determine sediment-water exchange rates, and the annual averages of these methods agree within the uncertainty of the determinations, about 20%. The annual average of benthic fluxes from shoal areas is nearly a factor of 2 greater than fluxes from the channel areas. Fluxes from the shoal and channel areas exceed those expected from simple molecular diffusion by factors of 4 and 2, respectively, apparently due to macrofaunal irrigation. Values of the gas transfer coefficient for radon exchange across the air-water interface were determined by constructing a radon mass balance for the water column and by direct measurement using floating chambers. The chamber method appears to yield results which are too high. Transfer coefficients computed using the mass balance method range from 0.4 m/day to 1.8 m/day, with a 6-year average of 1.0 m/day. Gas exchange is linearly dependent upon wind speed over a wind speed range of 3.2–6.4 m/s, but shows no dependence upon current velocity. Gas transfer coefficients predicted from an empirical relationship between gas exchange rates and wind speed observed in lakes and the oceans are within 30% of the coefficients determined from the radon mass balance and are considerably more accurate than coefficients predicted from theoretical gas exchange models.

  3. Microwave assisted chemical vapor infiltration

    SciTech Connect

    Devlin, D.J.; Currier, R.P.; Barbero, R.S.; Espinoza, B.F.; Elliott, N.

    1991-12-31

    A microwave assisted process for production of continuous fiber reinforced ceramic matrix composites is described. A simple apparatus combining a chemical vapor infiltration reactor with a conventional 700 W multimode oven is described. Microwave induced inverted thermal gradients are exploited with the ultimate goal of reducing processing times on complex shapes. Thermal gradients in stacks of SiC (Nicalon) cloths have been measured using optical thermometry. Initial results on the ``inside out`` deposition of SiC via decomposition of methyltrichlorosilane in hydrogen are presented. Several key processing issues are identified and discussed. 5 refs.

  4. A novel experiment for measuring infiltration into seasonal frozen soil

    NASA Astrophysics Data System (ADS)

    Demand, Dominic; Weiler, Markus

    2016-04-01

    Large parts of the northern hemisphere have at least seasonal frozen soils. Depending on the initial soil water content infiltration capacity can be reduced through pore blockage of ice. Many studies dealing with this topic used numerical modelling for estimating the effect of frozen soils on infiltration. Only a few studies investigated the influences of seasonal frozen soils on infiltration and runoff generation in field experiments. Some authors point out that preferential flow can be an important factor under frozen conditions, but only qualitative information are available so far. A missing methodology makes it hard to measure and quantify infiltration into frozen soils, especially the role of preferential flow. Therefore, a novel multi-method approach for measuring the influences of seasonal frozen soil on infiltration is presented. Sprinkling experiments with a rate of 50 mm/h were performed at frozen soil plots under wet and dry initial conditions in a grassland field site in the Black Forest, Germany. Additionally, two different water temperatures were used for the sprinkling experiments (~2°C and ~10°C). Thermal infrared imagery was tested for continuous, in-situ monitoring of the spatiotemporal soil thermal state during infiltration and the possibility to derive information on water flow. A dye tracer (Brilliant Blue FCF) was added to the infiltrating water and analyzed by image analysis for flow patterns and depth distribution. Thermal infrared imagery and dye tracer were used for the first time in field experiments in frozen soils and were tested for their potential to show the effect of preferential flow under frozen conditions. These information were related to observed soil moisture and temperature profiles measured with capacitance probes in five depths. Furthermore timing and amount of surface runoff was examined for all plots. Brilliant Blue flow patterns and surface runoff were compared against unfrozen soils with similar initial conditions

  5. Evaluation of Surface Infiltration Testing Procedures in Permeable Pavement Systems

    EPA Science Inventory

    The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete provides limited guidance on how to select testing locations, so research is needed to evaluate how testing sites should be selected and how results should be interpreted to assess surface ...

  6. High-repetition-rate laser ignition of fuel-air mixtures.

    PubMed

    Hsu, Paul S; Roy, Sukesh; Zhang, Zhili; Sawyer, Jordan; Slipchenko, Mikhail N; Mance, Jason G; Gord, James R

    2016-04-01

    A laser-ignition (LI) method is presented that utilizes a high-repetition-rate (HRR) nanosecond laser to reduce minimal ignition energies of individual pulses by ∼10 times while maintaining comparable total energies. The most common LI employs a single nanosecond-laser pulse with energies on the order of tens of millijoules to ignite combustible gaseous mixtures. Because of the requirements of high energy per pulse, fiber coupling of traditional LI systems is difficult to implement in real-world systems with limited optical access. The HRR LI method demonstrated here has an order of magnitude lower per-pulse energy requirement than the traditional single-pulse LI technique, potentially allowing delivery through standard commercial optical fibers. Additionally, the HRR LI approach significantly increases the ignition probability of lean combustible mixtures in high-speed flows while maintaining low individual pulse energies.

  7. [Infiltration characteristics of soil water on loess slope land under intermittent and repetitive rainfall conditions].

    PubMed

    Li, Yi; Shao, Ming-An

    2008-07-01

    Based on the experiments of controlled intermittent and repetitive rainfall on slope land, the infiltration and distribution characteristics of soil water on loess slope land were studied. The results showed that under the condition of intermittent rainfall, the cumulative runoff during two rainfall events increased linearly with time, and the wetting front also increased with time. In the interval of the two rainfall events, the wetting front increased slowly, and the infiltration rate was smaller on steeper slope than on flat surface. During the second rainfall event, there was an obvious decreasing trend of infiltration rate with time. The cumulative infiltration on 15 degrees slope land was larger than that of 25 degrees slope land, being 178 mm and 88 mm, respectively. Under the condition of repetitive rainfall, the initial infiltration rate during each rainfall event was relatively large, and during the first rainfall, both the infiltration rate and the cumulative infiltration at various stages were larger than those during the other three rainfall events. However, after the first rainfall, there were no obvious differences in the infiltration rate among the next three rainfall events. The more the rainfall event, the deeper the wetting front advanced.

  8. Infiltration and permeability testing at geokinetics oil shale site

    SciTech Connect

    Hoylman, E.W.; Quinn, G.W.

    1984-03-01

    Infiltration (double-rint) and pressure permeability (packer) tests were conducted in or near true in-situ oil shale retorts and at adjacent undisturbed locations to obtain comparative data to evaluate the potential for groundwater pollution due to increased fluid migration resulting from this retorting methodology. Tests were performed at the Geokinetics oil shale site located in Section 2, Township 14 South, Range 22 East, Uintah County, Utah. Test results suggest a slight increase in surface infiltration rates and hydraulic conductivity in or near the retort areas. It is expected that this type of true in-situ retorting will pose very little, if any, threat to groundwater resources in the area.

  9. Climatic Forecasting of Net Infiltration at Yucca Montain Using Analogue Meteororological Data

    SciTech Connect

    B. Faybishenko

    2006-09-11

    At Yucca Mountain, Nevada, future changes in climatic conditions will most likely alter net infiltration, or the drainage below the bottom of the evapotranspiration zone within the soil profile or flow across the interface between soil and the densely welded part of the Tiva Canyon Tuff. The objectives of this paper are to: (a) develop a semi-empirical model and forecast average net infiltration rates, using the limited meteorological data from analogue meteorological stations, for interglacial (present day), and future monsoon, glacial transition, and glacial climates over the Yucca Mountain region, and (b) corroborate the computed net-infiltration rates by comparing them with the empirically and numerically determined groundwater recharge and percolation rates through the unsaturated zone from published data. In this paper, the author presents an approach for calculations of net infiltration, aridity, and precipitation-effectiveness indices, using a modified Budyko's water-balance model, with reference-surface potential evapotranspiration determined from the radiation-based Penman (1948) formula. Results of calculations show that net infiltration rates are expected to generally increase from the present-day climate to monsoon climate, to glacial transition climate, and then to the glacial climate. The forecasting results indicate the overlap between the ranges of net infiltration for different climates. For example, the mean glacial net-infiltration rate corresponds to the upper-bound glacial transition net infiltration, and the lower-bound glacial net infiltration corresponds to the glacial transition mean net infiltration. Forecasting of net infiltration for different climate states is subject to numerous uncertainties-associated with selecting climate analogue sites, using relatively short analogue meteorological records, neglecting the effects of vegetation and surface runoff and runon on a local scale, as well as possible anthropogenic climate changes.

  10. Association between indoor air pollutant exposure and blood pressure and heart rate in subjects according to body mass index.

    PubMed

    Jung, Chien-Cheng; Su, Huey-Jen; Liang, Hsiu-Hao

    2016-01-01

    This study investigates the effects of high body mass index (BMI) of subjects on individual who exhibited high cardiovascular disease indexes with blood pressure (BP) and heart rate (HR) when exposed to high levels of indoor air pollutants. We collected 115 office workers, and measured their systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR at the end of the workday. The subjects were divided into three groups according to BMI: 18-24 (normal weight), 24-27 (overweight) and >27 (obese). This study also measured the levels of carbon dioxide (CO2), total volatile organic compounds (TVOC), particulate matter with an aerodynamic diameter less than 2.5μm (PM2.5), as well as the bacteria and fungi in the subjects' work-places. The pollutant effects were divided by median. Two-way analysis of variance (ANOVA) was used to analyze the health effects of indoor air pollution exposure according to BMI. Our study showed that higher levels of SBP, DBP and HR occurred in subjects who were overweight or obese as compared to those with normal weight. Moreover, there was higher level of SBP in subjects who were overweight or obese when they were exposed to higher levels of TVOC and fungi (p<0.05). We also found higher value for DBP and HR with increasing BMI to be associated with exposure to higher TVOC levels. This study suggests that individuals with higher BMI have higher cardiovascular disease risk when they are exposed to poor indoor air quality (IAQ), and specifically in terms of TVOC.

  11. Continuous measurements of air change rates in an occupied house for 1 year: the effect of temperature, wind, fans, and windows.

    PubMed

    Wallace, L A; Emmerich, S J; Howard-Reed, C

    2002-07-01

    A year-long investigation of air change rates in an occupied house was undertaken to establish the effects of temperature, wind velocity, use of exhaust fans, and window-opening behavior. Air change rates were calculated by periodically injecting a tracer gas (SF(6)) into the return air duct and measuring the concentration in 10 indoor locations sequentially every minute by a gas chromatograph equipped with an electron capture detector. Temperatures were also measured outdoors and in the 10 indoor locations. Relative humidity (RH) was measured outdoors and in five indoor locations every 5 min. Wind speed and direction in the horizontal plane were measured using a portable meteorological station mounted on the rooftop. Use of the thermostat-controlled attic fan was recorded automatically. Indoor temperatures increased from 21 degrees C in winter to 27 degrees C in summer. Indoor RH increased from 20% to 70% in the same time period. Windows were open only a few percent of the time in winter but more than half the time in summer. About 4600 hour-long average air change rates were calculated from the measured tracer gas decay rates. The mean (SD) rate was 0.65 (0.56) h(-1). Tracer gas decay rates in different rooms were very similar, ranging only from 0.62 to 0.67 h(-1), suggesting that conditions were well mixed throughout the year. The strongest influence on air change rates was opening windows, which could increase the rate to as much as 2 h(-1) for extended periods, and up to 3 h(-1) for short periods of a few hours. The use of the attic fan also increased air change rates by amounts up to 1 h(-1). Use of the furnace fan had no effect on air change rates. Although a clear effect of indoor-outdoor temperature difference could be discerned, its magnitude was relatively small, with a very large temperature difference of 30 degrees C (54 degrees F) accounting for an increase in the air change rate of about 0.6 h(-1). Wind speed and direction were found to have very

  12. [Lymphoid infiltrates in the lung].

    PubMed

    Szalontai, K; Krenács, L; Csanádi, J; Ugocsai, K; Kraszkó, P

    1993-11-07

    The authors reviewed material of 10 year period (1980-1990) of the Department of Pulmonology, Albert Szent-Györgyi University of Medicine, Deszk, Hungary, and selected 14 patients from the files who considered to belong in one of the lymphoproliferative conditions (4 low grade and 4 high grade lymphomas of B-cell type, 1 angiocentric, 1 mediastinal lymphoblastic non-Hodgkin's lymphoma, 3 Hodgkin's lymphoma cases and 1 pleural pseudolymphoma). Every patient admitted with prominent pulmonary symptoms. The diagnoses were based on histology and immunohistochemistry of tissue samples and autopsy. One high grade B-cell and the angiocentric malignant lymphoma proved to be primary pulmonary process. No specific radiomorphological signs were found, which could be characteristic for the pulmonary lympho-reticular infiltrations and also to distinct the primary and secondary ones. The lung infiltrations in the most of the non-Hodgkin's lymphoma cases with low grade malignancy appeared imitating tuberculosis, while the high grade group and Hodgkin's lymphomas displayed confusion with any primary or multiple tumors.

  13. Combustion rate limits of hydrogen plus hydrocarbon fuel: Air diffusion flames from an opposed jet burner technique

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Guerra, Rosemary; Wilson, Lloyd G.; Reeves, Ronald N.; Northam, G. Burton

    1987-01-01

    Combustion of H2/hydrocarbon (HC) fuel mixtures may be considered in certain volume-limited supersonic airbreathing propulsion applications. Effects of HC addition to H2 were evaluated, using a recent argon-bathed, coaxial, tubular opposed jet burner (OJB) technique to measure the extinction limits of counterflow diffusion flames. The OJB flames were formed by a laminar jet of (N2 and/or HC)-diluted H2 mixture opposed by a similar jet of air at ambient conditions. The OJB data, derived from respective binary mixtures of H2 and methane, ethylene, or propane HCs, were used to characterize BLOWOFF and RESTORE. BLOWOFF is a sudden breaking of the dish-shaped OJB flame to a stable torus or ring shape, and RESTORE marks sudden restoration of the central flame by radial inward flame propagation. BLOWOFF is a measure of kinetically-limited flame reactivity/speed under highly stretched, but relatively ideal impingement flow conditions. RESTORE measures inward radial flame propagation rate, which is sensitive to ignition processes in the cool central core. It is concluded that relatively small molar amounts of added HC greatly reduce the reactivity characteristics of counterflow hydrogen-air diffusion flames, for ambient initial conditions.

  14. SENSOR FOR INDIVIDUAL BURNER CONTROL OF FIRING RATE, FUEL-AIR RATIO, AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill; Roger Demler; Robert G. Mudry

    2005-04-01

    A no-cost time extension was requested, to permit additional laboratory testing prior to undertaking field data collection. This was received in this reporting period. To minimize program cost, this additional testing is planned to be performed in concert with EPRI-funded testing at the Coal Flow Test Facility. Since the EPRI schedule was undecided, a hiatus occurred in the test effort. Instead, a significant effort was exerted to analyze the available laboratory test data to see whether the source and nature of noise behaviors could be identified, or whether the key flow information could be extracted even in the presence of the noise. One analysis approach involved filtering the data numerically to reject dynamics outside of various frequency bands. By varying the center frequency and width of the band, the effect of signal frequency on flow dynamics could be examined. Essentially equivalent results were obtained for all frequency bands that excluded a neighborhood of the transducer resonance, indicating that there is little advantage to be gained by limiting the experimental frequency window. Another approach examined the variation of the dynamics over a series of 1-second windows of data, producing an improvement in the prediction of coal flow rate. Yet another approach compared the dynamics of a series of 1-second windows to those of a series of 5-second windows, producing still better results. These results will be developed further in the next reporting period, which should also include further laboratory testing at the Coal Flow Test Facility.

  15. SENSOR FOR INDIVIDUAL BURNER CONTROL OF FIRING RATE, FUEL-AIR RATIO, AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill; Roger Demler; Robert G. Mudry

    2005-01-01

    Additional calibration data were collected in the Coal Flow Test Facility early in this reporting period. These data comprised a total of 181 tests for stud and magnetic accelerometer mounts, with two mounting locations relative to two different pipe elbows, and including some tests with out-of-plane elbows upstream of the test section to produce coal ''roping''. The results found in analyzing these new data were somewhat disappointing: correlations for coal flow rate for a given mount type and mounting location were less accurate than desired, and degraded badly when data from other locations were included in the same analysis. Reviewing all of the data files (from both the earlier testing and recent calibration testing) disclosed a significant fraction of cases with several forms of noise. Eliminating these cases improved the correlations somewhat, but the number of cases that remained did not permit general conclusions to be drawn. It was finally learned that yet another type of noise is present in some data files, producing a strong effect on the correlation accuracy. The cases not subject to this noise correlated very well. It would be desirable to collect additional data in the Coal Flow Test Facility prior to moving on to field data collection, a change in program direction that would require a no-cost time extension.

  16. Characterization of interstitial infiltrating cells in Berger's disease.

    PubMed

    Sabadini, E; Castiglione, A; Colasanti, G; Ferrario, F; Civardi, R; Fellin, G; D'Amico, G

    1988-10-01

    The role of infiltrating blood-borne cells in the pathogenesis of renal damage in human glomerulonephritis is under active investigation. We have evaluated leukocyte infiltrates (number of cells/mm2) in the renal interstitium of 21 patients with Berger's disease and eight normal kidneys with monoclonal antibodies and a four-layer immunoperoxidase technique. In our population of patients, the number of infiltrating T-lymphocytes (OKT11+ cells) was significantly higher (median, 132) than in the normal kidneys (median, 60). This increase was mainly due to T-suppressor/cytotoxic lymphocytes (OKT8+ cells; median, 68), while T-helper/inducer lymphocytes (Leu 3A+ cells) and monocytes were in the normal range. T-lymphocyte infiltration was more marked in ten patients with impaired glomerular filtration rate (GFR) at the time of biopsy (median, 167) than in patients with normal GFR (median, 88). In addition, ten patients who showed deterioration of renal function during the subsequent follow-up, whatever their serum creatinine levels at the time of biopsy, had significantly more total T cells (median, 269), OKT8+ cells (median, 143), and Leu 3A+ cells (median, 105) than 11 patients with persistently stable GFR and normal controls. More data are necessary to establish whether this T-lymphocyte infiltration is the consequence of a cell-mediated mechanism acting in the interstitium, concomitant with the immune-complex-mediated mechanism acting in the glomerulus, or is a nonspecific consequence of the tubulointerstitial damage induced by the immunologically mediated glomerular disease.

  17. Characterizing ponded infiltration in a dry cracked clay soil

    NASA Astrophysics Data System (ADS)

    Bouma, J.; Wösten, J. H. M.

    1984-02-01

    Ponded infiltration in a dry cracked clay soil was studied in large blocks of soil (upper surface area 1500 cm 2, height 25-40 cm) using physical and morphological methods. Blocks were encased in gypsum. Physical measurements included: (1) infiltration rates into the block and into subsoil below the block during shallow ponding; (2) D- θ relations of soil in the block; and (3) depth and degree of wetting in soil adjacent to the cracks. Cracks in the block were then filled with a gypsum slurry. Morphological measurements included Quantimet ® counts of the surface area ( A) and the peripheral length ( L) of the gypsum-filled cracks, using in situ drawings. Simulation of horizontal infiltration from the cracks, using D( θ)- and L-values, yielded results that agreed well with in situ measurements, demonstrating the mutual compatibility of the morphological and physical methods.

  18. Chemical characterization of indoor air of homes from communes in Xuan Wei, China, with high lung cancer mortality rate

    NASA Astrophysics Data System (ADS)

    Chuang, J. C.; Cao, S. R.; Xian, Y. L.; Harris, D. B.; Mumford, J. L.

    In a rural county, Xuan Wei, China, the lung cancer mortality rate is among China's highest, especially in women. This mortality rate is more associated with indoor air burning of smoky coal, as opposed to smokeless coal or wood, for cooking and heating under unvented conditions. Homes using different fuels from communes with high and low lung cancer mortality rates were sampled for particulate matter (< 10 μm) and semivolatile organics. The fine particles obtained from homes using smoky coal contained highest concentrations of organic matter (> 70%), including PAH, followed by homes using wood and smokeless coal. The major components present in the smoky coal filter samples were PAH and alkylated PAH. The smokeless coal filter samples exhibited profiles which were similar to the smoky coal samples except that some sulfur compounds were found. The estimated concentration levels of PAH in the smokeless coal samples were about one to two orders of magnitude lower than those of the smoky coal samples. In addition to PAH, aliphatic compounds and fatty acids were the major components found in the wood samples. Selected sample extracts from homes using smoky coal were fractionated into four fractions, and the results showed that the PAH and polar fractions have high mutagenic activity. Chemical characterization of the PAH fraction indicated that concentrations of some alkylated PAH were higher than those of their parent compounds. Chemical characterization of the polar fractions showed that nitrogen heterocyclic compounds are present.

  19. Heart rate and heart rate variability assessment identifies individual differences in fear response magnitudes to earthquake, free fall, and air puff in mice.

    PubMed

    Liu, Jun; Wei, Wei; Kuang, Hui; Tsien, Joe Z; Zhao, Fang

    2014-01-01

    Fear behaviors and fear memories in rodents have been traditionally assessed by the amount of freezing upon the presentation of conditioned cues or unconditioned stimuli. However, many experiences, such as encountering earthquakes or accidental fall from tree branches, may produce long-lasting fear memories but are behaviorally difficult to measure using freezing parameters. Here, we have examined changes in heartbeat interval dynamics as physiological readout for assessing fearful reactions as mice were subjected to sudden air puff, free-fall drop inside a small elevator, and a laboratory-version earthquake. We showed that these fearful events rapidly increased heart rate (HR) with simultaneous reduction of heart rate variability (HRV). Cardiac changes can be further analyzed in details by measuring three distinct phases: namely, the rapid rising phase in HR, the maximum plateau phase during which HRV is greatly decreased, and the recovery phase during which HR gradually recovers to baseline values. We showed that durations of the maximum plateau phase and HR recovery speed were quite sensitive to habituation over repeated trials. Moreover, we have developed the fear resistance index based on specific cardiac response features. We demonstrated that the fear resistance index remained largely consistent across distinct fearful events in a given animal, thereby enabling us to compare and rank individual mouse's fear responsiveness among the group. Therefore, the fear resistance index described here can represent a useful parameter for measuring personality traits or individual differences in stress-susceptibility in both wild-type mice and post-traumatic stress disorder (PTSD) models.

  20. Biodrying of sewage sludge: kinetics of volatile solids degradation under different initial moisture contents and air-flow rates.

    PubMed

    Villegas, Manuel; Huiliñir, Cesar

    2014-12-01

    This study focuses on the kinetics of the biodegradation of volatile solids (VS) of sewage sludge for biodrying under different initial moisture contents (Mc) and air-flow rates (AFR). For the study, a 3(2) factorial design, whose factors were AFR (1, 2 or 3L/minkgTS) and initial Mc (59%, 68% and 78% w.b.), was used. Using seven kinetic models and a nonlinear regression method, kinetic parameters were estimated and the models were analyzed with two statistical indicators. Initial Mc of around 68% increases the temperature matrix and VS consumption, with higher moisture removal at lower initial Mc values. Lower AFRs gave higher matrix temperatures and VS consumption, while higher AFRs increased water removal. The kinetic models proposed successfully simulate VS biodegradation, with root mean square error (RMSE) between 0.007929 and 0.02744, and they can be used as a tool for satisfactory prediction of VS in biodrying.

  1. Quantifying Molecular Hydrogen Emissions and an Industrial Leakage Rate for the South Coast Air Basin of California

    NASA Astrophysics Data System (ADS)

    Irish, M. C.; Schroeder, J.; Beyersdorf, A. J.; Blake, D. R.

    2015-12-01

    The poorly understood atmospheric budget and distribution of molecular hydrogen (H2) have invited further research since the discovery that emissions from a hydrogen-based economy could have negative impacts on the global climate system and stratospheric ozone. The burgeoning fuel cell electric vehicle industry in the South Coast Air Basin of California (SoCAB) presents an opportunity to observe and constrain urban anthropogenic H2 emissions. This work presents the first H2 emissions estimate for the SoCAB and calculates an upper limit for the current rate of leakage from production and distribution infrastructure within the region. A top-down method utilized whole air samples collected during the Student Airborne Research Program (SARP) onboard the NASA DC-8 research aircraft from 23-25 June 2015 to estimate H2 emissions from combustion and non-combustion sources. H2:carbon monoxide (CO) and H2:carbon dioxide ratios from airborne observations were compared with experimentally established ratios from pure combustion source ratios and scaled with the well-constrained CO emissions inventory to yield H2 emissions of 24.9 ± 3.6 Gg a-1 (1σ) from combustion engines and 8.2 ± 4.7 Gg a-1 from non-combustion sources. Total daily production of H2 in the SoCAB was compared with the top-down results to estimate an upper limit leakage rate (5%) where all emissions not accounted for by incomplete combustion in engines were assumed to be emitted from H2 infrastructure. For bottom-up validation, the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory dispersion model was run iteratively with all known stationary sources in attempt to constrain emissions. While this investigation determined that H2 emissions from non-combustion sources in the SoCAB are likely significant, more in-depth analysis is required to better predict the atmospheric implications of a hydrogen economy.

  2. Hydraulic characteristics and nutrient transport and transformation beneath a rapid infiltration basin, Reedy Creek Improvement District, Orange County, Florida

    USGS Publications Warehouse

    Sumner, D.M.; Bradner, L.A.

    1996-01-01

    The Reedy Creek Improvement District disposes of about 7.5 million gallons per day (1992) of reclaimed water through 85 1-acre rapid infiltration basins within a 1,000-acre area of sandy soils in Orange County, Florida. The U.S. Geological Survey conducted field experiments in 1992 at an individual basin to examine and better understand the hydraulic characteristics and nutrient transport and transformation of reclaimed water beneath a rapid infiltration basin. At the time, concentrations of total nitrogen and total phosphorus in reclaimed water were about 3 and 0.25 milligrams per liter, respectively. A two-dimensional, radial, unsaturated/saturated numerical flow model was applied to describe the flow system beneath a rapid infiltration basin under current and hypothetical basin loading scenarios and to estimate the hydraulic properties of the soil and sediment beneath a basin. The thicknesses of the unsaturated and saturated parts of the surficial aquifer system at the basin investigated were about 37 and 52 feet, respectively. The model successfully replicated the field-monitored infiltration rate (about 5.5 feet per day during the daily flooding periods of about 17 hours) and ground-water mounding response during basin operation. Horizontal and vertical hydraulic conductivity of the saturated part of the surficial aquifer system were estimated to be 150 and 45 feet per day, respectively. The field-saturated vertical hydraulic conductivity of the shallow soil, estimated to be about 5.1 feet per day, was considered to have been less than the full- saturation value because of the effects of air entrapment. Specific yield of the surficial aquifer was estimated to be 0.41. The upper 20 feet of the basin subsurface profile probably served as a system control on infiltration because of the relatively low field-saturated, vertical hydraulic conductivity of the sediments within this layer. The flow model indicates that, in the vicinity of the basin, flow in the deeper

  3. Streamflow, Infiltration, and Recharge in Arroyo Hondo, New Mexico

    USGS Publications Warehouse

    Moore, Stephanie J.

    2007-01-01

    Infiltration events in channels that flow only sporadically produce focused recharge to the Tesuque aquifer in the Espa?ola Basin. The current study examined the quantity and timing of streamflow and associated infiltration in Arroyo Hondo, an unregulated mountain-front stream that enters the basin from the western slope of the Sangre de Cristo Mountains. Traditional methods of stream gaging were combined with environmental-tracer based methods to provide the estimates. The study was conducted during a three-year period, October 1999?October 2002. The period was characterized by generally low precipitation and runoff. Summer monsoonal rains produced four brief periods of streamflow in water year 2000, only three of which extended beyond the mountain front, and negligible runoff in subsequent years. The largest peak flow during summer monsoon events was 0.59 cubic meters per second. Snowmelt was the main contributor to annual streamflow. Snowmelt produced more cumulative flow downstream from the mountain front during the study period than summer monsoonal rains. The presence or absence of streamflow downstream of the mountain front was determined by interpretation of streambed thermographs. Infiltration rates were estimated by numerical modeling of transient vertical streambed temperature profiles. Snowmelt extended throughout the instrumented reach during the spring of 2001. Flow was recorded at a station two kilometers downstream from the mountain front for six consecutive days in March. Inverse modeling of this event indicated an average infiltration rate of 1.4 meters per day at this location. For the entire study reach, the estimated total annual volume of infiltration ranged from 17,100 to 246,000 m3 during water years 2000 and 2001. During water year 2002, due to severe drought, streamflow and streambed infiltration in the study reach were both zero.

  4. The measured energy impact of air leakage on frame wall systems. Final report

    SciTech Connect

    Bhattacharyya, S.

    1991-06-01

    Infiltration is customarily assumed to increase the heating and cooling load of a building by an amount equal to the mass flow rate of the infiltration times the enthalpy difference between the inside and outside air -- with the latent portion of the enthalpy difference sometimes neglected. An experimental and analytical investigation has been conducted on the actual energy impact of air leakage on frame wall systems. Calorimetric measurements conducted on a small test cell and on a well characterized stud-cavity wall specimen with measured amounts of air leakage introduced under a variety of controlled conditions and configurations show convincingly that infiltration can lead to a much smaller change in the energy load than is customarily calculated. The data also suggest that the phenomenon occurs in full-sized houses as well. Infiltration Heat Exchange Effectiveness (IHEE),{var_epsilon}, is introduced as a measure of the effectiveness of a building in ``recovering`` heat otherwise lost (or gained) because of infiltration. Measurements show that {var_epsilon} increases as: (a) flow rate decreases; (b) flow path length increases; and, (c) hole/crack size decreases.

  5. The measured energy impact of air leakage on frame wall systems

    SciTech Connect

    Bhattacharyya, S.

    1991-06-01

    Infiltration is customarily assumed to increase the heating and cooling load of a building by an amount equal to the mass flow rate of the infiltration times the enthalpy difference between the inside and outside air -- with the latent portion of the enthalpy difference sometimes neglected. An experimental and analytical investigation has been conducted on the actual energy impact of air leakage on frame wall systems. Calorimetric measurements conducted on a small test cell and on a well characterized stud-cavity wall specimen with measured amounts of air leakage introduced under a variety of controlled conditions and configurations show convincingly that infiltration can lead to a much smaller change in the energy load than is customarily calculated. The data also suggest that the phenomenon occurs in full-sized houses as well. Infiltration Heat Exchange Effectiveness (IHEE),{var epsilon}, is introduced as a measure of the effectiveness of a building in recovering'' heat otherwise lost (or gained) because of infiltration. Measurements show that {var epsilon} increases as: (a) flow rate decreases; (b) flow path length increases; and, (c) hole/crack size decreases.

  6. Effects of Thinning Intensities on Soil Infiltration and Water Storage Capacity in a Chinese Pine-Oak Mixed Forest

    PubMed Central

    Chen, Lili; Yuan, Zhiyou; Shao, Hongbo; Wang, Dexiang; Mu, Xingmin

    2014-01-01

    Thinning is a crucial practice in the forest ecosystem management. The soil infiltration rate and water storage capacity of pine-oak mixed forest under three different thinning intensity treatments (15%, 30%, and 60%) were studied in Qinling Mountains of China. The thinning operations had a significant influence on soil infiltration rate and water storage capacity. The soil infiltration rate and water storage capacity in different thinning treatments followed the order of control (nonthinning): <60%, <15%, and <30%. It demonstrated that thinning operation with 30% intensity can substantially improve soil infiltration rate and water storage capacity of pine-oak mixed forest in Qinling Mountains. The soil initial infiltration rate, stable infiltration rate, and average infiltration rate in thinning 30% treatment were significantly increased by 21.1%, 104.6%, and 60.9%, compared with the control. The soil maximal water storage capacity and noncapillary water storage capacity in thinning 30% treatment were significantly improved by 20.1% and 34.3% in contrast to the control. The soil infiltration rate and water storage capacity were significantly higher in the surface layer (0~20 cm) than in the deep layers (20~40 cm and 40~60 cm). We found that the soil property was closely related to soil infiltration rate and water storage capacity. PMID:24883372

  7. Effects of thinning intensities on soil infiltration and water storage capacity in a Chinese pine-oak mixed forest.

    PubMed

    Chen, Lili; Yuan, Zhiyou; Shao, Hongbo; Wang, Dexiang; Mu, Xingmin

    2014-01-01

    Thinning is a crucial practice in the forest ecosystem management. The soil infiltration rate and water storage capacity of pine-oak mixed forest under three different thinning intensity treatments (15%, 30%, and 60%) were studied in Qinling Mountains of China. The thinning operations had a significant influence on soil infiltration rate and water storage capacity. The soil infiltration rate and water storage capacity in different thinning treatments followed the order of control (nonthinning): <60%, <15%, and <30%. It demonstrated that thinning operation with 30% intensity can substantially improve soil infiltration rate and water storage capacity of pine-oak mixed forest in Qinling Mountains. The soil initial infiltration rate, stable infiltration rate, and average infiltration rate in thinning 30% treatment were significantly increased by 21.1%, 104.6%, and 60.9%, compared with the control. The soil maximal water storage capacity and noncapillary water storage capacity in thinning 30% treatment were significantly improved by 20.1% and 34.3% in contrast to the control. The soil infiltration rate and water storage capacity were significantly higher in the surface layer (0~20 cm) than in the deep layers (20~40 cm and 40~60 cm). We found that the soil property was closely related to soil infiltration rate and water storage capacity.

  8. [METHODOLOGY FOR THE ASSESSMENT OF THE IMPACT OF THE ATMOSPHERIC AIR POLLUTION ON THE FORMATION OF THE LEVELS OF OVERALL MORBIDITY RATE OF BRONCHIAL ASTHMA].

    PubMed

    Veremchuk, L V; Cherpack, N A; Gvozdenko, T A; Volkova, M V

    2015-01-01

    In large cities with strong air pollution the formation of the levels of morbidity rate of bronchial asthma has a complex causation that requires the search for informative methods for identification of causes and consequences of this dependence. Method for the assessment of the dependence of overall levels of morbidity rate of bronchial asthma on the degree of air pollution allows you to select a "useful information" of the direct impact of air pollution on a background of random processes and latent relationship between human and environment. The use of the method of the information entropy analysis allowed us to estimate the total and the individual contribution of the separate components of air pollution on the formation of levels of total morbidity rate of bronchial asthma in the population of the city of Vladivostok. Levels of total incidence of this pathology were established to differ in various age groups. The adult population is more adapted to air pollution, but retains a high sensitivity to the impact of nitrogen dioxide. Levels of overall l morbidity rate of bronchial asthma in children and adolescents depend on the total air pollution with some dominance of the influence of suspended matter and carbon monoxide.

  9. Relationship between heart rate variability, blood pressure and arterial wall properties during air and oxygen breathing in healthy subjects.

    PubMed

    Graff, Beata; Szyndler, Anna; Czechowicz, Krzysztof; Kucharska, Wiesława; Graff, Grzegorz; Boutouyrie, Pierre; Laurent, Stephane; Narkiewicz, Krzysztof

    2013-11-01

    Previous studies reported that normobaric hyperoxia influences heart rate, arterial pressure, cardiac output and systemic vascular resistance, but the mechanisms underlying these changes are still not fully understood. Several factors are considered including degeneration of endothelium-derived nitric oxide by reactive oxygen species, the impact of oxygen-free radicals on tissues and alterations of autonomic nervous system function. Recently, new devices for the detailed non-invasive assessment of large and small arteries have been developed. Therefore, the aim of our study was to assess heart rate variability (HRV) as a potential indicator of autonomic balance and its relation to blood pressure and vascular properties during medical air (MAB) and 100% oxygen breathing (OXB) in healthy volunteers. In 12 healthy subjects we assessed heart rate and blood pressure variability, baroreflex sensitivity, respiratory frequency, common carotid artery diameter and its wall distensibility, as well as changes in the digital artery pulse waveform, stroke index and systemic vascular resistance during MAB and OXB. Mean and systolic blood pressure have increased significantly while digital pulse amplitude and carotid artery diameter were significantly lower during hyperoxia. Heart rate variability measures did not differ during MAB and OXB. However, the correlations between spectral HRV components and those hemodynamic parameters which have changed due to hyperoxia varied substantially during MAB (correlated significantly) and OXB (no significant correlations were noted). Our findings suggest that autonomic nervous system might not be the main mediator of the cardiovascular changes during 100% oxygen breathing in healthy subjects. It seems that the direct vascular responses are initial consequences of hyperoxia and other cardiovascular parameter alterations are secondary to them.

  10. Infiltration of river water to a shallow aquifer investigated with 3H/ 3He, noble gases and CFCs

    NASA Astrophysics Data System (ADS)

    Beyerle, U.; Aeschbach-Hertig, W.; Hofer, M.; Imboden, D. M.; Baur, H.; Kipfer, R.

    1999-09-01

    Noble gas isotopes ( 3He, 4He, Ne, Ar, Kr, Xe), tritium ( 3H), chlorofluorocarbons (CFCs) and dissolved oxygen (O 2) were seasonally measured in a small groundwater system recharged by infiltration of river water at Linsental, northeastern Switzerland. All Groundwater samples contained an excess of atmospheric noble gases ('excess air') usually with an elemental composition equal to air. The concentrations of atmospheric noble gases in the groundwater were used to calculate the excess air component and the water temperature at recharge. The noble gas temperatures (NGTs) in the boreholes close to the river vary seasonally, however, the average NGT of all samples lies close to the mean annual temperature of the river water. Groundwater ages were calculated using the tritium/helium-3 ( 3H/ 3He) dating method. The water ages of the samples obtained near the river depend on the amount of recently infiltrated river water and are young during times of active river discharge. In contrast, the mean water age of about 3 years of the deep aquifer remained nearly constant over the sampling period. The observed CFC-11 (CFCl 3) and CFC-12 (CF 2Cl 2) concentrations are significantly higher than the atmospheric equilibrium concentrations and therefore CFCs do not provide any direct information on the residence time of the groundwater. Nevertheless, the CFC excess in the groundwater shows a linear increase with the 3H/ 3He age. Additionally, both accumulation of radiogenic He ( 4He rad) and O 2 consumption are strongly correlated with residence time. All these correlations can be interpreted either in terms of mixing of recently infiltrated river water with older groundwater or in terms of accumulation/consumption rates.

  11. Field study and simulation of diurnal temperature effects on infiltration and variably saturated flow beneath an ephemeral stream

    USGS Publications Warehouse

    Ronan, A.D.; Prudic, D.E.; Thodal, C.E.; Constantz, J.

    1998-01-01

    Two experiments were performed to investigate flow beneath an ephemeral stream and to estimate streambed infiltration rates. Discharge and stream-area measurements were used to determine infiltration rates. Stream and subsurface temperatures were used to interpret subsurface flow through variably saturated sediments beneath the stream. Spatial variations in subsurface temperatures suggest that flow beneath the streambed is dependent on the orientation of the stream in the canyon and the layering of the sediments. Streamflow and infiltration rates vary diurnally: Stream flow is lowest in late afternoon when stream temperature is greatest and highest in early morning when stream temperature is least. The lower afternoon streamflow is attributed to increased infiltration rates; evapotranspiration is insufficient to account for the decreased streamflow. The increased infiltration rates are attributed to viscosity effects on hydraulic conductivity from increased stream temperatures. The first set of field data was used to calibrate a two-dimensional variably saturated flow model that includes heat transport. The model was calibrated to (1) temperature fluctuations in the subsurface and (2) infiltration rates determined from measured stream flow losses. The second set of field data was to evaluate the ability to predict infiltration rates on the basis of temperature measurements alone. Results indicate that the variably saturated subsurface flow depends on downcanyon layering of the sediments. They also support the field observations in indicating that diurnal changes in infiltration can be explained by temperature dependence of hydraulic conductivity. Over the range of temperatures and flows monitored, diurnal stream temperature changes can be used to estimate streambed infiltration rates. It is often impractical to maintain equipment for determining infiltration rates by traditional means; however, once a model is calibrated using both infiltration and temperature data

  12. Field Test Evaluation of Conservation Retrofits of Low-Income, Single-Family Buildings in Wisconsin: Blower-Door-Directed Infiltration Reduction Procedure, Field Test Implementation and Results

    SciTech Connect

    Gettings, M.B.

    2001-05-21

    A blower-door-directed infiltration retrofit procedure was field tested on 18 homes in south central Wisconsin. The procedure, developed by the Wisconsin Energy Conservation Corporation, includes recommended retrofit techniques as well as criteria for estimating the amount of cost-effective work to be performed on a house. A recommended expenditure level and target air leakage reduction, in air changes per hour at 50 Pascal (ACH50), are determined from the initial leakage rate measured. The procedure produced an average 16% reduction in air leakage rate. For the 7 houses recommended for retrofit, 89% of the targeted reductions were accomplished with 76% of the recommended expenditures. The average cost of retrofits per house was reduced by a factor of four compared with previous programs. The average payback period for recommended retrofits was 4.4 years, based on predicted energy savings computed from achieved air leakage reductions. Although exceptions occurred, the procedure's 8 ACH50 minimum initial leakage rate for advising retrofits to be performed appeared a good choice, based on cost-effective air leakage reduction. Houses with initial rates of 7 ACH50 or below consistently required substantially higher costs to achieve significant air leakage reductions. No statistically significant average annual energy savings was detected as a result of the infiltration retrofits. Average measured savings were -27 therm per year, indicating an increase in energy use, with a 90% confidence interval of 36 therm. Measured savings for individual houses varied widely in both positive and negative directions, indicating that factors not considered affected the results. Large individual confidence intervals indicate a need to increase the accuracy of such measurements as well as understand the factors which may cause such disparity. Recommendations for the procedure include more extensive training of retrofit crews, checks for minimum air exchange rates to insure air quality

  13. Prevalence rates of respiratory symptoms in Italian general population samples exposed to different levels of air pollution

    SciTech Connect

    Viegi, G. Univ. of Arizona, Tucson ); Paoletti, P.; Carrozzi, L.; Vellutini, M.; Diviggiano, E.; Pistelli, G.; Giutini, G. ); Di Pede, C. Occupational Medicine Service, Toscana ); Lebowitz, M.D. )

    1991-08-01

    The authors surveyed two general population samples aged 8 to 64 living in the unpolluted, rural area of the Po Delta (northern Italy) and in the urban area of Pisa (central Italy). Each subject filled out a standardized interviewer-administered questionnaire. The Pisa sample was divided into three groups according to their residence in the urban-suburban areas and to outdoor air pollution exposure (automobile exhaust only or industrial fumes as well). Significantly higher prevalence rates of all the respiratory symptoms and diseases were found in Pisa compared with the Po Delta. Current smoking was more frequent in the rural area, but the urban smokers had a higher lifetime cigarette consumption. Childhood respiratory trouble and recurrent respiratory illnesses were evenly distributed. Exposure to parental smoking in childhood and lower educational level were more frequent in Po Delta, whereas familial history of respiratory/allergic disorders and work and indoor exposures were more often reported in the city. Multiple logistic regression models estimating independently the role of the various risk factors showed significant odds ratios associated with residence in Pisa for all the symptoms but chronic phlegm. The conclusion, these preliminary analyses indicate an urban factor related to the rates of respiratory symptoms and diseases in Italy in the 1980s.

  14. Oxidation rate of nuclear-grade graphite NBG-18 in the kinetic regime for VHTR air ingress accident scenarios

    NASA Astrophysics Data System (ADS)

    Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

    2013-07-01

    One of the most severe accident scenarios anticipated for VHTRs is an air ingress accident caused by a pipe break. Graphite oxidation could be severe under these conditions. In this work, the oxidation rate of NBG-18 nuclear-grade graphite was studied thermogravimetrically for different oxygen concentrations and with temperatures from 873 to 1873 K. A semi-empirical Arrhenius rate equation was developed for the temperature range of 873-1023 K. The activation energy of NBG-18 was 187 kJ/mol and the order of reaction was 1.25. The penetration depth of oxidant was about 3-4 mm for NBG-18 oxidized at 973 K. Increased porosity and changes in external geometry became more prominent at higher temperatures from about 1173 to 1873 K. The surface of oxidized NBG-18 was characterized by SEM, EDS, FTIR and XPS. Diffusion of oxygen to the graphite surface and walls of open volume pores. Adsorption of oxygen atoms on the graphite surface free active sites and complexes inducing the simultaneous forming of Csbnd O and Csbnd H bonds and breaking of Csbnd C bonds (dissociative chemisorption). Chemical reactions occur at the surface. Desorption of gaseous products, CO and CO2, from the graphite surface and transport to the bulk gas mixture.

  15. SIMULATION OF NET INFILTRATION FOR MODERN AND POTENTIAL FUTURE CLIMATES

    SciTech Connect

    J.A. Heveal

    2000-06-16

    This Analysis/Model Report (AMR) describes enhancements made to the infiltration model documented in Flint et al. (1996) and documents an analysis using the enhanced model to generate spatial and temporal distributions over a model domain encompassing the Yucca Mountain site, Nevada. Net infiltration is the component of infiltrated precipitation, snowmelt, or surface water run-on that has percolated below the zone of evapotranspiration as defined by the depth of the effective root zone, the average depth below the ground surface (at a given location) from which water is removed by evapotranspiration. The estimates of net infiltration are used for defining the upper boundary condition for the site-scale 3-dimensional Unsaturated-Zone Ground Water Flow and Transport (UZ flow and transport) Model (CRWMS M&O 2000a). The UZ flow and transport model is one of several process models abstracted by the Total System Performance Assessment model to evaluate expected performance of the potential repository at Yucca Mountain, Nevada, in terms of radionuclide transport (CRWMS M&O 1998). The net-infiltration model is important for assessing potential repository-system performance because output from this model provides the upper boundary condition for the UZ flow and transport model that is used to generate flow fields for evaluating potential radionuclide transport through the unsaturated zone. Estimates of net infiltration are provided as raster-based, 2-dimensional grids of spatially distributed, time-averaged rates for three different climate stages estimated as likely conditions for the next 10,000 years beyond the present. Each climate stage is represented using a lower bound, a mean, and an upper bound climate and corresponding net-infiltration scenario for representing uncertainty in the characterization of daily climate conditions for each climate stage, as well as potential climate variability within each climate stage. The set of nine raster grid maps provide spatially

  16. Fluid infiltration pressure for hydrophobic nanochannels

    NASA Astrophysics Data System (ADS)

    Mo, Jingwen; Li, Long; Zhou, Jianfeng; Xu, Dongyan; Huang, Baoling; Li, Zhigang

    2015-03-01

    We investigate water infiltration pressure for hydrophobic nanochannels through molecular dynamics simulations. It is found that the entrance energy barrier significantly raises the infiltration pressure, which makes the classic Young-Laplace equation invalid for nanochannels. As the channel surface is tuned from superhydrophobic to hydrophobic, the infiltration pressure is greatly reduced mainly due to the decrease of the capillary pressure (Young-Laplace equation) caused by the contact angle change, while the contribution of the entrance energy barrier to the infiltration pressure, which is termed entrance barrier pressure, increases from 25% to 60%.

  17. A review of reaction rates and thermodynamic and transport properties for the 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.

    1989-01-01

    Reaction rate coefficients and thermodynamic and transport properties are provided for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in such environments.

  18. Release and dispersal of basidiospores from Amanita muscaria var. alba and their infiltration into a residence.

    PubMed

    Li, De-Wei

    2005-11-01

    Release and dispersal of basidiospores of Amanita muscaria var. alba and their potential to infiltrate a nearby residence were investigated. Basidiospore release mainly occurred in the first three days following the expansion of the caps. The concentrations of released basidiospores near basidiomata were 77 137, 75 062, and 41 738 spores m(-3) in the first three days, respectively, with the highest concentration at 281 738 spores m(-3) air. After three days, the concentration dropped by 95%. At the second location, airborne basidiospore concentrations dropped 96-99% after three days with the concentrations of 940, 575, and 1359 spores m(-3) in the first three days, respectively. The diurnal pattern showed a relatively extended night peak. Relative humidity and dew were positively correlated with basidiospore release and short distance dispersal. Rain and rain rate were positively correlated with basidiospore release, but not correlated with short distance dispersal. The basidiospore release period of Amanita muscaria var. alba was short, but within such a period it released a large amount of basidiospores. However, only less than 5% of basidiospores released were dispersed to the second location 5.2 m away and 2.7 m above the basidiomata. Only < 0.1% of basidiospores dispersed from the basidiomata were found inside a nearby residence. Amanita muscaria var. alba showed a low potential of infiltrating the residence.

  19. The characteristics of coarse particulate matter air pollution associated with alterations in blood pressure and heart rate during controlled exposures

    PubMed Central

    Morishita, Masako; Bard, Robert L.; Wang, Lu; Das, Ritabrata; Dvonch, J. Timothy; Spino, Catherine; Mukherjee, Bhramar; Sun, Qinghua; Harkema, Jack R.; Rajagopalan, Sanjay; Brook, Robert D.

    2015-01-01

    Although fine particulate matter (PM) air pollution <2.5 μm in aerodynamic diameter (PM2.5) is a leading cause of global morbidity and mortality, the potential health effects of coarse PM (2.5–10 μm in aerodynamic diameter; PM10–2.5) remain less clearly understood. We aimed to elucidate the components within coarse PM most likely responsible for mediating these hemodynamic alterations. Thirty-two healthy adults (25.9 ± 6.6 years) were exposed to concentrated ambient coarse PM (CAP) (76.2 ± 51.5 μg/m3) and filtered air (FA) for 2 h in a rural location in a randomized double-blind crossover study. The particle constituents (24 individual elements, organic and elemental carbon) were analyzed from filter samples and associated with the blood pressure (BP) and heart rate (HR) changes occurring throughout CAP and FA exposures in mixed model analyses. Total coarse PM mass along with most of the measured elements were positively associated with similar degrees of elevations in both systolic BP and HR. Conversely, total PM mass was unrelated, whereas only two elements (Cu and Mo) were positively associated with and Zn was inversely related to diastolic BP changes during exposures. Inhalation of coarse PM from a rural location rapidly elevates systolic BP and HR in a concentration-responsive manner, whereas the particulate composition does not appear to be an important determinant of these responses. Conversely, exposure to certain PM elements may be necessary to trigger a concomitant increase in diastolic BP. These findings suggest that particulate mass may be an adequate metric of exposure to predict some, but not all, hemodynamic alterations induced by coarse PM mass. PMID:25227729

  20. Effects of white grubs on soil water infiltration.

    PubMed

    Romero-López, A A; Rodríguez-Palacios, E; Alarcón-Gutiérrez, E; Geissert, D; Barois, I

    2015-04-01

    Water infiltration rates k were measured in mesocosms with soil and "white grubs" of Ancognatha falsa (Arrow) (Coleoptera: Melolonthidae). Three third instars of A. falsa and three adult earthworms Pontoscolex corethrurus were selected, weighted, and introduced into the mesocosms setting three treatments: soil + A. falsa, soil + P. corethrurus, and control (soil without any macroorganism). The experiment had a completely random design with four replicates per treatment (n = 4). The infiltration rates of soil matrix were assessed in each mesocosms with a minidisk tension infiltrometer. Six measurements were made along the experiment. Results showed that larvae of A. falsa promoted a higher water infiltration in the soil, compared to the control. On day 7, k values were similar among treatments, but k values after 28 days and up to 100 days were much higher in the A. falsa treatment (k = 0.00025 cm s(-1)) if compared to control (k = 0.00011 cm s(-1)) and P. corethrurus (k = 0.00008 cm s(-1)) treatments. The k values were significantly higher in the presence of larvae of A. falsa compared to the control and P. corethrurus treatments. The larvae of A. falsa are potential candidates for new assays on soil water infiltration with different tensions to evaluate the role of pores and holes created by the larvae on soils.

  1. ANEMOS: A computer code to estimate air concentrations and ground deposition rates for atmospheric nuclides emitted from multiple operating sources

    SciTech Connect

    Miller, C.W.; Sjoreen, A.L.; Begovich, C.L.; Hermann, O.W.

    1986-11-01

    This code estimates concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operating Sources. ANEMOS is one component of an integrated Computerized Radiological Risk Investigation System (CRRIS) developed for the US Environmental Protection Agency (EPA) for use in performing radiological assessments and in developing radiation standards. The concentrations and deposition rates calculated by ANEMOS are used in subsequent portions of the CRRIS for estimating doses and risks to man. The calculations made in ANEMOS are based on the use of a straight-line Gaussian plume atmospheric dispersion model with both dry and wet deposition parameter options. The code will accommodate a ground-level or elevated point and area source or windblown source. Adjustments may be made during the calculations for surface roughness, building wake effects, terrain height, wind speed at the height of release, the variation in plume rise as a function of downwind distance, and the in-growth and decay of daughter products in the plume as it travels downwind. ANEMOS can also accommodate multiple particle sizes and clearance classes, and it may be used to calculate the dose from a finite plume of gamma-ray-emitting radionuclides passing overhead. The output of this code is presented for 16 sectors of a circular grid. ANEMOS can calculate both the sector-average concentrations and deposition rates at a given set of downwind distances in each sector and the average of these quantities over an area within each sector bounded by two successive downwind distances. ANEMOS is designed to be used primarily for continuous, long-term radionuclide releases. This report describes the models used in the code, their computer implementation, the uncertainty associated with their use, and the use of ANEMOS in conjunction with other codes in the CRRIS. A listing of the code is included in Appendix C.

  2. Measured Infiltration and Ventilation in Manufactured Homes : Residential Construction Demonstration Project, Cycle II.

    SciTech Connect

    Palmiter, Larry S.

    1992-04-28

    Air infiltration is an important factor in heat loss and indoor air quality; in modern well-insulated homes, it may account for as much as half of the total heat loss. Due to the recent emphasis by home buyers and manufacturers on energy efficiency, tighter homes are being constructed. In the past, it was assumed that natural infiltration would provide adequate ventilation to maintain acceptable indoor air quality, but this is no longer the case in modern energy-efficient homes. This report summarizes the results of infiltration measurements made on two groups of manufactured homes in the Bonneville Power Administration (BPA) service area: 131 energy-efficient homes constructed under RCDP, and a control group of 29 homes not participating in energy-efficiency programs.

  3. Natural variation of ambient dose rate in the air of Izu-Oshima Island after the Fukushima Daiichi Nuclear Power Plant accident.

    PubMed

    Maedera, Fumihiko; Inoue, Kazumasa; Sugino, Masato; Sano, Ryosuke; Furue, Mai; Shimizu, Hideo; Tsuruoka, Hiroshi; Le Van, Tan; Fukushi, Masahiro

    2016-03-01

    The ambient dose rate in air and radioactivity concentration in soil samples collected on Izu-Oshima Island were observed in 2012, 2013 and 2014, i.e. 1, 2 and 3 years after the severe accident at the Fukushima Daiichi Nuclear Power Plant. A car-borne survey for the ambient dose rate in air was carried out for the entire island. Soil samples were collected for the radioactivity concentration measurements from 22 points. The ambient dose rates in air were 36 nGy h(-1) in 2012, 34 nGy h(-1) in 2013 and 29 nGy h(-1) in 2014. The corresponding radioactivity concentrations in those years for (134)Cs were 53, 39 and 29 Bq kg(-1) and for (137)Cs, 87, 73 and 75 Bq kg(-1). All the values have decreased every year.

  4. Equivalence in Ventilation and Indoor Air Quality

    SciTech Connect

    Sherman, Max; Walker, Iain; Logue, Jennifer

    2011-08-01

    We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

  5. Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

    PubMed

    Martens, D E; Nollen, E A; Hardeveld, M; van der Velden-de Groot, C A; de Gooijer, C D; Beuvery, E C; Tramper, J

    1996-01-01

    The death rate of Vero cells grown on Cytodex-3 microcarriers was studied as a function of the gas flow rate in a small air-lift loop reactor. The death rate may be described by first-order death-rate kinetics. The first-order death-rate constant as calculated from the decrease in viable cells, the increase in dead cells and the increase in LDH activity is linear proportional to the gas flow rate, with a specific hypothetical killing volume in which all cells are killed of about 2·10(-3) m(3) liquid per m(3) of air bubbles. In addition, an experiment was conducted in the same air-lift reactor with Vero cells grown inside porous Asahi microcarriers. The specific hypothetical killing volume calculated from this experiment has a value of 3·10(-4) m(3) liquid per m(3) of air bubbles, which shows that the porous microcarriers were at least in part able to protect the cells against the detrimental hydrodynamic forces generated by the bubbles.

  6. Smog O3 Production Rate in California Air: Marker Compounds Allow Checks on Source Attribution to Fire and Other Sources

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Esswein, R. F.; Cai, C.; Kaduwela, A.; Kulkarni, S.; Blake, D. R.; Weinheimer, A. J.; Fried, A.; Huey, L. G.

    2012-12-01

    We are able to attribute sources of both radical reactivity and NO that determined the smog-chemical production rate of ozone, P(O3), for NASA's wide-ranging sampling of California air in June, 2008, part of the ARCTAS intensive. We relate formaldehyde, HCHO, and reactive nitrogen oxides, NOx, to a variety of distinct "marker" species that identify origins. We have labeled the sources and markers as (i) Fire emissions (CH3CN), (ii) Biogenic emissions (Isoprene), (iii) Urban/business emissions (CHCl3), (iv) Transport-related fuel consumption, (SO2), and (v) Refining/Port emissions ("residual" toluene). We use multiple linear regression with some appropriate restrictions. We achieve R-squared or explained variance of 88% for HCHO (VOC's) and 60% for NOx. HCHO and NOx are slowly evolving measures of potential ozone generation. The two related but radiation-influenced measures j (HCHO->H+HCO) x [HCHO] and [NO] quantitatively, but non-linearly, relate to instantaneous ozone production in California air, with R-squared of 86-93%, just as in New York City (Chatfield et al., Atmos. Environ., 2010). Maps of attribution for 650 samples from the Port of San Diego to the Northern Sierra foothills, and offshore -— all show huge variability in source attributions for VOCs and NOx. They indicate a widespread fire-emission influence on VOCs as they produce peroxy radicals, but show no positive influence on NOx, in fact consuming NOx from other sources. Comparisons with simulations help to refine our attribution classes and also to check balances of VOC emissions in available inventories. The use of the P(O3) measures is directly translatable to a method for estimate smog-ozone production rate from space, as data from another intensive, DISCOVER-AQ, show. (Left) A rare example where all sources contribute significantly, with markers and tentative attributions marked. (Right) Three different situations describing the control of smog ozone production, all from the same geographic

  7. F-22 Pilot Heart Rate Response to +Gz and Relationship to Pilot Fitness Using U.S. Air Force Fitness Test Scores

    DTIC Science & Technology

    2015-08-19

    AFRL-SA-WP-SR-2015-0024 F-22 Pilot Heart Rate Response to +Gz and Relationship to Pilot Fitness Using U.S. Air Force Fitness Test Scores...To) July 2013 – June 2015 4. TITLE AND SUBTITLE F-22 Pilot Heart Rate Response to +Gz and Relationship to Pilot Fitness Using U.S. Air Force... Fitness Test Scores 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Marie-France M. McIntee, Mark J

  8. Experimental determination of the velocity and strain rate field in a laminar H2/Air counter-flow diffusion flame via LDA

    NASA Technical Reports Server (NTRS)

    Yeo, S. H.; Dancey, C. L.

    1991-01-01

    Measurements of the axial and radial components of velocity on the air side of stagnation in an axisymmetric H2/Air laminar counter-flow diffusion flame are reported. Results include the two-dimensional velocity field and computed velocity gradients (strain rates) along the stagnation streamline at two 'characteristic' strain rates, below the extinction limit. The measurements generally verify the modeling assumptions appropriate to the model of Kee et al. (1988). The 'traditional' potential flow model is not consistent with the measured results.

  9. A surface and subsurface model for the simulation of rainfall infiltration in slopes

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Zhang, F.; Shen, K.; Yuan, M.

    2015-09-01

    Rainfall infiltration is one of the major triggering factors leading to slope failures in geotechnical engineering. Numerical investigation on rainfall infiltration is often based on Richards’ equation, which ignores the surface water effects and simplifies the boundary conditions. In reality, rainfall, infiltration, and surface runoff are interacted simultaneously. In this paper a new conjunctive one-dimensional surface flow and two-dimensional subsurface flow model for geotechnical slope is developed. The interaction between surface and subsurface flow is the interface infiltration rate, which is obtained by iterations. The results of comparisons between coupled and uncoupled models show that the surface water depth rises up as runoff increases and it tends to a dynamic balance state with a steady surface water depth. Interaction between surface and subsurface flow has remarkable effects on infiltration process. According to the results of coupled model, more rainwaters infiltrate into the slope. Therefore, pore water pressure changes faster and the wetting front moves deeper into the soil. Under initial drier condition, the capacity of infiltration is higher and more rainfall can be absorbed into slope, thus the differences of infiltration rate and pore water pressure between the coupled and uncoupled model are more significant.

  10. General characteristics of U.S. Air Force and U.S. Army rated male and female aircrew.

    PubMed

    Voge, V M

    1996-11-01

    The issue of women flying military combat aircraft has been controversial. We conducted a comprehensive survey, via anonymous questionnaire, of all U.S. Army and U.S. Air Force rated female aircrew and an equal number of age- and duty-matched male aircrew. We are reporting on the general information section of the questionnaire here: age, time in the military, flight role, desire to remain in the military, marital status, number of children, spousal encouragement of career, type of aircraft flown, aircraft mishap and injury history, and reasons for extended period of illness/medical incapacitation to fly. Males' and females' responses in most areas surveyed were very similar. However, women were more than twice as likely to have been medically grounded for a period of more than 30 days. Not all the excess groundings were due to pregnancies. The responses to this section of the questionnaire indicate that female military officer aircrew are similar to their male counterparts. About 20% of married female aircrew do not postpone pregnancies in deference to their military careers.

  11. SU-E-P-15: Technique Factor Modulation and Reference Plane Air Kerma Rates in Response to Simulated Patient Thickness Variations for a Sample of Current Generation Fluoroscopes

    SciTech Connect

    Wunderle, K; Rakowski, J; Dong, F

    2015-06-15

    Purpose: To evaluate and compare approaches to technique factor modulation and air kerma rates in response to simulated patient thickness variations for four state-of-the-art and one previous-generation interventional fluoroscopes. Methods: A polymethyl methacrylate (PMMA) phantom was used as a tissue surrogate for the purposes of determining fluoroscopic reference plane air kerma rates, kVp, mA, and spectral filtration over a wide range of simulated tissue thicknesses. Data were acquired for each fluoroscopic and acquisition dose curve within a default abdomen or body imaging protocol. Results: The data obtained indicated vendor- and model-specific variations in the approach to technique factor modulation and reference plane air kerma rates across a range of tissue thicknesses. Some vendors have made hardware advances increasing the radiation output capabilities of their fluoroscopes; this was evident in the acquisition air kerma rates. However, in the imaging protocol evaluated, all of the state-of-the-art systems had relatively low air kerma rates in the fluoroscopic low-dose imaging mode as compared to the previous-generation unit. Each of the newest-generation systems also employ copper filtration in the selected protocol in the acquisition mode of imaging; this is a substantial benefit, reducing the skin entrance dose to the patient in the highest dose-rate mode of fluoroscope operation. Conclusion: Understanding how fluoroscopic technique factors are modulated provides insight into the vendor-specific image acquisition approach and provides opportunities to optimize the imaging protocols for clinical practice. The enhanced radiation output capabilities of some of the fluoroscopes may, under specific conditions, may be beneficial; however, these higher output capabilities also have the potential to lead to unnecessarily high dose rates. Therefore, all parties involved in imaging, including the clinical team, medical physicists, and imaging vendors, must work

  12. [Soil infiltration capacity under different vegetations in southern Ningxia Loess hilly region].

    PubMed

    Yang, Yong-Hui; Zhao, Shi-Wei; Lei, Ting-Wu; Liu, Han

    2008-05-01

    A new apparatus for measuring the run off-on-out under simulated rainfall conditions was used to study the soil infiltration capacity under different rainfall intensities and vegetations in loess hilly region of southern Ningxia, with the relationships between soil water-stable aggregate content and soil stable infiltration rate under different vegetations analyzed. The results showed that the regression equations between rainfall duration and soil infiltration rate under different vegetations all followed y = a + be(-cx), with R2 ranged from 0.9678 to 0.9969. With the increase of rainfall intensity, the soil stable infiltration rate on slope cropland decreased, while that on Medicago lupulina land, natural grassland, and Caragana korshinskii land increased. Under the rainfall intensity of 20 mm h(-1), the rainfall infiltration translation rate (RITR) was decreased in the order of M. lupulina land > slope cropland > natural grassland > C. korshinskii land; while under the rainfall intensity of 40 mm h(-1) and 56 mm h(-1), the RITR was in the sequence of M. lupulina land > natural grassland > slope cropland > C. korshinskii land, and decreased with increasing rainfall intensity. After the reversion of cropland to grassland and forest land, and with the increase of re-vegetation, the amount of >0.25 mm soil aggregates increased, and soil infiltration capacity improved. The revegetation in study area effectively improved soil structure and soil infiltration capacity, and enhanced the utilization potential of rainfall on slope.

  13. The impacts of short-term exposure to noise and traffic-related air pollution on heart rate variability in young healthy adults.

    PubMed

    Huang, Jing; Deng, Furong; Wu, Shaowei; Lu, Henry; Hao, Yu; Guo, Xinbiao

    2013-01-01

    Traffic-related air pollution and noise are associated with cardiovascular diseases, and alternation of heart rate variability (HRV), which reflects cardiac autonomic function, is one of the mechanisms. However, few studies considered the impacts of noise when exploring associations between air pollution and HRV. We explored whether noise modifies associations between short-term exposure to traffic-related air pollution and HRV in young healthy adults. In this randomized, crossover study, 40 young healthy adults stayed for 2 h in a traffic center and, on a separate occasion, in a park. Personal exposure to traffic-related air pollutants and noise were measured and ambulatory electrocardiogram was performed. Effects were estimated using mixed-effects regression models. Traffic-related air pollution and noise were both associated with HRV, and effects of air pollutants were amplified at high noise level (>65.6 A-weighted decibels (dB[A])) compared with low noise level (≤ 65.6 dB[A]). High frequency (HF) decreased by -4.61% (95% confidence interval, -6.75% to-2.42%) per 10 μg/m(3) increment in fine particle (PM2.5) at 5-min moving average, but effects became insignificant at low noise level (P>0.05). Similar effects modification was observed for black carbon (BC) and carbon monoxide (CO). We conclude that noise is an important factor influencing the effects of air pollution on HRV.

  14. Evaluation of Soil Media for Stormwater Infiltration Best Management Practices (BMPs)

    EPA Science Inventory

    This project will improve the performance of structural management practices, and provide guidance that will allow designers to balance infiltration rates with sorption capacity. This project will also perform a standard column test procedure for evaluating candidate soil media.

  15. Effects of sodium polyacrylate on water retention and infiltration capacity of a sandy soil.

    PubMed

    Zhuang, Wenhua; Li, Longguo; Liu, Chao

    2013-01-01

    Based on the laboratory study, the effects of sodium polyacrylate (SP) was investigated at 5 rates of 0, 0.08, 0.2, 0.5, and 1%, on water retention, saturated hydraulic conductivity(Ks), infiltration characteristic and water distribution profiles of a sandy soil. The results showed that water retention and available water capacity effectively increased with increasing SP rate. The Ks and the rate of wetting front advance and infiltration under certain pond infiltration was significantly reduced by increasing SP rate, which effectively reduced water in a sandy soil leaking to a deeper layer under the plough layer. The effect of SP on water distribution was obviously to the up layer and very little to the following deeper layers. Considering both the effects on water retention and infiltration capacity, it is suggested that SP be used to the sandy soil at concentrations ranging from 0.2 to 0.5%.

  16. Investigations of infiltration processes from flooded areas by column experiments

    NASA Astrophysics Data System (ADS)

    Mohrlok, U.; Bethge, E.; Golalipour, A.

    2009-04-01

    In case of inundation of flood plains during flood events there is an increased risk of groundwater contamination due to infiltration of increasingly polluted river water. Specifically in densely populated regions, this groundwater may be used as source for drinking water supply. For the evaluation of this a detailed quantitative understanding of the infiltration processes under such conditions is required. In this context the infiltration related to a flood event can be described by three phases. The first phase is defined by the saturation of the unsaturated soils. Within the second phase infiltration takes place under almost saturated conditions determined by the hydraulic load of the flood water level. The drainage of the soils due to falling groundwater table is characterizing the third phase. Investigations by soil columns gave a detailed insight into the infiltration processes caused by flooding. Inflow at the soil top was established by a fixed water table fed by a Mariotte bottle. Free outflow and a groundwater table were used as lower boundary condition. Inflow and outflow volume were monitored. The evolution of the matrix pressure was observed by micro-tensiometers installed at several depths within the soil column. The flow processes during phase one and two were characterized by a tracer test. Some of the experiments were repeated in order to study the influence of preliminary events. Main results were a difference in infiltration due to the lower boundary condition with regard to inflow rate, outflow dynamics and matrix pressure evolution which is directly related to the water content evolution. Further, the influence of preliminary events was different for the different boundary conditions. A replacement of pre-event water could be observed which was confirmed by volume balances calculated for the infiltration experiments. Although these water balances were almost closed significant dynamics of the matrix pressure remained in soil column in the

  17. Concrete grinding residue characterization and influence on infiltration.

    PubMed

    DeSutter, T; Prunty, L; Bell, J

    2011-01-01

    Concrete grinding residue (CGR) is a slurry byproduct created by concrete pavement maintenance operations. Disposal of CGR slurry is presently regulated on the basis of very minimal information. The least immediate expense is incurred by spreading CGR slurry directly on vegetated roadway ditches and embankments. The direct disposal impacts to environmental quality in terms of soil physical or chemical properties are not known. Five CGR materials from widely dispersed sites in the United States were analyzed for particle size distribution and evaluated with a suite of USEPA physical and chemical analyses. Values found for the parameters examined are not considered harmful. An infiltration column study was also conducted in which two CGRs were mixed at 8 and 25% by weight and also surface applied 2.5 mm deep with two contrasting (relatively fine and coarse textured) soils. With the finer soil, statistically (p < 0.05) significant decrease in infiltration time (increased infiltration rate) was associated with the 25% and surface-applied CGR treatments, compared with the untreated control soil. The results indicate that excessive application of CGR may increase water infiltration into soil in the short-term. This should be kept in mind, but does not appear to be generally detrimental.

  18. Traffic-Related Air Pollution and Acute Changes in Heart Rate Variability and Respiratory Function in Urban Cyclists

    PubMed Central

    Kulka, Ryan; Dubeau, Aimee; Martin, Christina; Wang, Daniel; Dales, Robert

    2011-01-01

    Background: Few studies have examined the acute health effects of air pollution exposures experienced while cycling in traffic. Objectives: We conducted a crossover study to examine the relationship between traffic pollution and acute changes in heart rate variability. We also collected spirometry and exhaled nitric oxide measures. Methods: Forty-two healthy adults cycled for 1 hr on high- and low-traffic routes as well as indoors. Health measures were collected before cycling and 1–4 hr after the start of cycling. Ultrafine particles (UFPs; ≤ 0.1 μm in aerodynamic diameter), particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5), black carbon, and volatile organic compounds were measured along each cycling route, and ambient nitrogen dioxide (NO2) and ozone (O3) levels were recorded from a fixed-site monitor. Mixed-effects models were used to estimate associations between air pollutants and changes in health outcome measures relative to precycling baseline values. Results: An interquartile range increase in UFP levels (18,200/cm3) was associated with a significant decrease in high-frequency power 4 hr after the start of cycling [β = –224 msec2; 95% confidence interval (CI), –386 to –63 msec2]. Ambient NO2 levels were inversely associated with the standard deviation of normal-to-normal (NN) intervals (β = –10 msec; 95% CI, –20 to –0.34 msec) and positively associated with the ratio of low-frequency to high-frequency power (β = 1.4; 95% CI, 0.35 to 2.5) 2 hr after the start of cycling. We also observed significant inverse associations between ambient O3 levels and the root mean square of successive differences in adjacent NN intervals 3 hr after the start of cycling. Conclusions: Short-term exposures to traffic pollution may contribute to altered autonomic modulation of the heart in the hours immediately after cycling. PMID:21672679

  19. Integrated modelling for the evaluation of infiltration effects.

    PubMed

    Schulz, N; Baur, R; Krebs, P

    2005-01-01

    The objective of the present study is the estimation of the potential benefits of sewer pipe rehabilitation for the performance of the drainage system and the wastewater treatment plant (WWTP) as well as for the receiving water quality. The relation of sewer system status and the infiltration rate is assessed based on statistical analysis of 470 km of CCTV (Closed Circuit Television) inspected sewers of the city of Dresden. The potential reduction of infiltration rates and the consequent performance improvements of the urban wastewater system are simulated as a function of rehabilitation activities in the network. The integrated model is applied to an artificial system with input from a real sewer network. In this paper, the general design of the integrated model and its data requirements are presented. For an exemplary study, the consequences of the simulations are discussed with respect to the prioritisation of rehabilitation activities in the network.

  20. Anion Absorption by Etiolated Wheat Leaves after Vacuum Infiltration

    PubMed Central

    MacDonald, I. R.; Macklon, A. E. S.

    1972-01-01

    Chloride and phosphate uptake by leaf segments of green and etiolated 7-day-old seedlings of Triticum aestivum L. cultivar Capelle is enhanced by light. In the range from 1.0 to 10 millimolar KCl, maximal rates of uptake were obtained with 1.5-millimeter segments. Above 1.5 millimeters, ion diffusion through the cut edge was the rate-limiting factor, uptake being proportional to the amount of cut edge, but vacuum infiltration of the tissue overcame this limitation, allowing uptake to be independent of segment length. No deleterious effects of vacuum infiltration were observed, and it is suggested that the technique offers a convenient alternative to existing methods in the study of foliar absorption. PMID:16657949

  1. Landslide triggering by rain infiltration

    USGS Publications Warehouse

    Iverson, Richard M.

    2000-01-01

    Landsliding in response to rainfall involves physical processes that operate on disparate timescales. Relationships between these timescales guide development of a mathematical model that uses reduced forms of Richards equation to evaluate effects of rainfall infiltration on landslide occurrence, timing, depth, and acceleration in diverse situations. The longest pertinent timescale is A/D0, where D0 is the maximum hydraulic diffusivity of the soil and A is the catchment area that potentially affects groundwater pressures at a prospective landslide slip surface location with areal coordinates x, y and depth H. Times greater than A/D0 are necessary for establishment of steady background water pressures that develop at (x, y, H) in response to rainfall averaged over periods that commonly range from days to many decades. These steady groundwater pressures influence the propensity for landsliding at (x, y, H), but they do not trigger slope failure. Failure results from rainfall over a typically shorter timescale H2/D0 associated with transient pore pressure transmission during and following storms. Commonly, this timescale ranges from minutes to months. The shortest timescale affecting landslide responses to rainfall is √(H/g), where g is the magnitude of gravitational acceleration. Postfailure landslide motion occurs on this timescale, which indicates that the thinnest landslides accelerate most quickly if all other factors are constant. Effects of hydrologic processes on landslide processes across these diverse timescales are encapsulated by a response function, R(t*) = √(t*/π) exp (-1/t*) - erfc (1/√t*), which depends only on normalized time, t*. Use of R(t*) in conjunction with topographic data, rainfall intensity and duration information, an infinite-slope failure criterion, and Newton's second law predicts the timing, depth, and acceleration of rainfall-triggered landslides. Data from contrasting landslides that exhibit rapid, shallow motion and slow, deep

  2. Heating rate measurements over 30 deg and 40 deg (half angle) blunt cones in air and helium in the Langley expansion tube facility

    NASA Technical Reports Server (NTRS)

    Reddy, N. M.

    1980-01-01

    Convective heat transfer measurements, made on the conical portion of spherically blunted cones (30 deg and 40 deg half angle) in an expansion tube are discussed. The test gases used were helium and air; flow velocities were about 6.8 km/sec for helium and about 5.1 km/sec for air. The measured heating rates are compared with calculated results using a viscous shock layer computer code. For air, various techniques to determine flow velocity yielded identical results, but for helium, the flow velocity varied by as much as eight percent depending on which technique was used. The measured heating rates are in satisfactory agreement with calculation for helium, assuming the lower flow velocity, the measurements are significantly greater than theory and the discrepancy increased with increasing distance along the cone.

  3. Radon entry rate analyses using in situ tracer gas method application.

    PubMed

    Froňka, A; Jílek, K

    2014-07-01

    Recently, the role of energy savings in indoor air quality deterioration has been extensively emphasised, predominantly in the context of significant air exchange rate reduction as a result of home energy retrofits. In case of refurbishment of existing buildings, the effect of energy-efficient technologies on indoor radon concentration is considerably complex and has to be carefully evaluated with respect to radon entry rate (RER) and air exchange rate alteration. For the purpose of detailed analysis of radon entry pathways, the unique infiltration experiment has been carried out using the tracer gas (N2O) method application in field conditions. Significant amount of experimental works has been done to provide an independent assessment of RER and air-exchange rate facilitating the analysis of fundamental factors influencing the indoor radon variations (e.g. indoor-outdoor pressure difference induced by wind, stack effect, heating, ventilation and operation of air-conditioning systems).

  4. Effects of H2O, CO2, and N2 Air Contaminants on Critical Airside Strain Rates for Extinction of Hydrogen-Air Counterflow Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Wilson, L. G.; Northam, G. B.; Guerra, Rosemary

    1989-01-01

    Coaxial tubular opposed jet burners (OJB) were used to form dish shaped counterflow diffusion flames (CFDF), centered by opposing laminar jets of H2, N2 and both clean and contaminated air (O2/N2 mixtures) in an argon bath at 1 atm. Jet velocities for flame extinction and restoration limits are shown versus wide ranges of contaminant and O2 concentrations in the air jet, and also input H2 concentration. Blowoff, a sudden breaking of CFDF to a stable ring shape, occurs in highly stretched stagnation flows and is generally believed to measure kinetically limited flame reactivity. Restore, a sudden restoration of central flame, is a relatively new phenomenon which exhibits a H2 dependent hysteresis from Blowoff. For 25 percent O2 air mixtures, mole for mole replacement of 25 percent N2 contaminant by steam increased U(air) or flame strength at Blowoff by about 5 percent. This result is consistent with laminar burning velocity results from analogous substitution of steam for N2 in a premixed stoichiometric H2-O2-N2 (or steam) flame, shown by Koroll and Mulpuru to promote a 10 percent increase in experimental and calculated laminar burning velocity, due to enhanced third body efficiency of water in: H + O2 + M yields HO2 + M. When the OJB results were compared with Liu and MacFarlane's experimental laminar burning velocity of premixed stoichiometric H2 + air + steam, a crossover occurred, i.e., steam enhanced OJB flame strength at extinction relative to laminar burning velocity.

  5. Measurement of air kerma rates for 6- to 7-MeV high-energy gamma-ray field by ionisation chamber and build-up plate.

    PubMed

    Kowatari, Munehiko; Tanimura, Yoshihiko; Tsutsumi, Masahiro

    2014-12-01

    The 6- to 7-MeV high-energy gamma-ray calibration field by the (19)F(p, αγ)(16)O reaction is to be served at the Japan Atomic Energy Agency. For the determination of air kerma rates using an ionisation chamber in the 6- to 7-MeV high-energy gamma-ray field, the establishment of the charged particle equilibrium must be achieved during measurement. In addition to measurement of air kerma rates by the ionisation chamber with a thick build-up cap, measurement using the ionisation chamber and a build-up plate (BUP) was attempted, in order to directly determine air kerma rates under the condition of regular calibration for ordinary survey meters and personal dosemeters. Before measurements, Monte Carlo calculations were made to find the optimum arrangement of BUP in front of the ionisation chamber so that the charged particle equilibrium could be well established. Measured results imply that air kerma rates for the 6- to 7-MeV high-energy gamma-ray field could be directly determined under the appropriate condition using an ionisation chamber coupled with build-up materials.

  6. Effect of air flow rate on the polyphenols content and antioxidant capacity of convective dried cactus pear cladodes (Opuntia ficus indica).

    PubMed

    Gallegos-Infante, José-Alberto; Rocha-Guzman, Nuria-Elizabeth; González-Laredo, Ruben-Francisco; Reynoso-Camacho, Rosalia; Medina-Torres, Luis; Cervantes-Cardozo, Veronica

    2009-01-01

    The interest in nopal has encouraged the use of dehydration; there are few studies about the effect of process parameters on the nopal polyphenol content and antioxidant activity. The objective of the present work was to evaluate the effect of air-drying flow rates on the amount and antioxidant capacity of extracts of Opuntia ficus indica cladodes. Nopal was dried at 45 degrees C and air flow rates of 3 and 5 m/sec. Samples were analyzed for moisture, total polyphenol, flavonoid, and flavonol contents, chain-breaking activity, inhibition of low-density lipoprotein and deoxyribose oxidation. Nopal drying at an air flow rate of 3 m/sec showed higher values of phenols, flavonoids and flavonols. The best value of low-density lipoprotein inhibition and deoxyribose was found at 1,000 microg/ml. The air flow rate affected the amount of polyphenols and the OH( . ) radical scavenging, but did not modify the chain-breaking activity and the low-density lipoprotein inhibition activity.

  7. Experimental study on burning rates of square/rectangular gasoline and methanol pool fires under longitudinal air flow in a wind tunnel.

    PubMed

    Hu, L H; Liu, S; Peng, W; Huo, R

    2009-09-30

    Square pool fires with length of 5, 7.5, 10, 15, 20, 25 and 30 cm and rectangular pool fires with dimensions of 10 cm x 20 cm and 10 cm x 40 cm were burned in a wind tunnel, under a longitudinal air flow ranged from 0 to 3m/s with incremental change of about 0.5m/s. Methanol and gasoline were burned and compared, with results indicated that their burning rates showed different response to the longitudinal air flow. With the increase of the longitudinal air flow speed, the burning rates of methanol pool fires, except the 5 cm square one, first decreased and then increased, but those of the 5 cm methanol square one and the gasoline pool fires increased monotonously. The burning rate of smaller square pool fires increased more significantly than that of the larger ones, as well as the enlargement of their flame attachment length along the ground. The burning rate of a rectangular pool fire with longer rim parallel to the longitudinal flow increased faster, but the flame attachment length seemed to increase more gradually, with the increase of the longitudinal air flow speed than that perpendicular to.

  8. Monitoring Preferential Flow During Infiltration Experiments

    NASA Astrophysics Data System (ADS)

    Jelinkova, V.; Votrubova, J.; Sanda, M.; Cislerova, M.

    2006-12-01

    Field ponded infiltration experiments monitored by electrical resistivity tomography (ERT) were conducted at the experimental site Liz, Sumava Mts., Southern Bohemia. Single-ring ponded infiltration experiments were carried out repeatedly using a set of permanently installed plastic infiltration rings and additional ring made of concrete. The preferential flow occurring during the infiltration experiment was monitored by means of invasive and non-invasive visualization of flow paths. For the noninvasive visualization two geophysical methods were tested, namely TDR and ERT. Geophysical measurements were taken before, during and after the infiltration. TDR measurements were conducted using Tektronix 1502C cable tester connected to three steel electrodes 1- m long installed vertically in the centre of the infiltration ring. ERT was done using the ARES device (the multi electrode VES employing the Wenner-Schlumberger method). After the initial period of clean water infiltration 10g/l NaCl solute was used to improve the ERT signal. The electrical resistivity images were reconstructed using RES2DINV (Geotomo software). In ERT images the evolution of infiltration processes is clearly visible however the preferential character of the flow is completely smeared. This is clear from the comparison of ERT images with the images of Brilliant Blue dye distribution taken from the dug out horizons at the end of infiltration. In addition, the ERT results show some inconsistencies, which are most probably related to the design and the scale of the ERT network which is not fully consistent with the assumption of the methods employed. The research has been performed in the frame of research projects VaV/650/5/03 and GACR 103/04/0663.

  9. Decreasing IV Infiltrates in the Pediatric Patient--System-Based Improvement Project.

    PubMed

    Major, Tracie Wilt; Huey, Tricia K

    2016-01-01

    Intravenous infiltrates pose tremendous risk for the hospitalized pediatric patient. Infiltrate events increase hospital-acquired harm, the number of painful procedures, use of supplies, length of stay, and nursing time; it threatens relationships essential in patient- and family-centered care. The goal of this quality improvement project was to achieve a 10% decrease in the baseline infiltrate rate on two inpatient units and in the overall infiltrate rate across all of the pediatric units. A Lean Six Sigma methodology was used to guide project activities. Improvement strategies focused on evidence-based education, intravenous (IV) catheter securement, and family engagement. A comparative purposive sample was used to evaluate the pre- and post-implementation period to determine if desired project success measures were achieved. Data analysis revealed positive results across all units, with the number of events (n = 51 pre; n = 19 post) and the infiltration rates (13.5 pre; 7.1 post) decreasing over a three-month period. A decrease was also noted in the overall percent of IVs that infiltrated in the first 24 hours (45% pre; 42% post). A statistically significant increase (t = 15.16; p < 0.001) was noted in nurses' education pre- and post-assessment survey scores. The family engagement strategy revealed overall parental responses to be 88% positive. By decreasing infiltrates, quality of care improved, resulting in the delivery of safe, effective, and patient-centered IV therapy.

  10. Using numerical simulation methods to predict the effects of balancing coal and primary air flow rates on furnace emissions

    SciTech Connect

    Schwab, M.J.; Nelson, R.K.; Hardman, R.R.; Facchiano, T.

    1996-12-31

    This paper presents the technical results of a computer modeling exercise to quantify the impacts of balanced and unbalanced coal flows on NO{sub x} emissions and other boiler performance indicators. Using Airflow Sciences Corporation`s proprietary codes, separate computational fluid dynamics models of the furnace region and coal nozzles of a 200 MW{sub e} tangentially-fired boiler equipped with an ABB C-E Services Low NO{sub x} Concentric Firing System (Level II) were constructed. In modeling the coal combustion process, the numerical simulation of gas conditions within the furnace is accomplished by coupling the fluid dynamics relationships with sub-models that predict heat transfer (conduction, convection and radiation), turbulence, coal particle trajectories and temperatures, coal devolatilization, char combustion and equilibrium (mixing limited) chemistry. The equilibrium chemistry sub-model defines concentrations of the products of combustion at all locations within the furnace, with the exception of NO{sub x} concentrations. The generation of NO{sub x} is decoupled from the CFD simulation and is determined using finite-rate chemistry. The model was validated using test results from a recently completed US Department of Energy-sponsored Clean Coal Project at Gulf Power Company`s Plant Lansing Smith Unit 2. Validation was accomplished through comparison of the model results with experimental data including NO{sub x} emissions, unburned carbon, furnace exit gas temperatures, carbon monoxide levels, and excess oxygen values. Following validation, additional simulations were run to quantify the effect of balanced and unbalanced coal flows. Conditions simulated included the as-found condition, a fully balanced condition, a mill-by-mill fully balanced condition, and a {+-}10 percent balanced condition. The results showed that NO{sub x} emissions were not significantly affected by improving the distributions of primary air and coal between the burners.

  11. Modeling of meltwater infiltration in subfreezing snow

    SciTech Connect

    Illangasekare, T.H.; Walter, R.J. Jr.; Meier, M.F.; Pfeffer, W.T. )

    1990-05-01

    A mathematical model which incorporates the processes that influence water flow and heat transfer in subfreezing snow was developed. Among the aspects of snow included are density and grain-size heterogeneities, capillary-pressure gradients, meltwater refreezing, time dependent hydraulic and thermal parameters, and heat conduction. From this conceptual mathematical model a numerical model of two-dimensional meltwater infiltration was developed. Results from various test cases show which data are most important to measure accurately in the field, in order to determine how the snowpack will respond to an introduction of meltwater. These simulations also show the importance of the orientation of the various layers which make up the snowpack and how randomly distributed heterogeneities can produce two-dimensional flow of meltwater under unsaturated conditions. Finally, it is demonstrated that various assumptions related to density and porosity variations, dimensionality of flow, capillary effects, etc., which have been made by past investigators for ideal situations may not be valid under many circumstances, and several suggestions are made for improving predictions of meltwater behavior. Sensitivity analysis showed that the model is most sensitive to changes in bulk density, residual saturation of wet snow and meltwater supply rates, whereas changes in snow temperature and mean grain size had less marked effect.

  12. Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel.

    PubMed

    Razus, D; Brinzea, V; Mitu, M; Movileanu, C; Oancea, D

    2011-06-15

    The maximum rates of pressure rise during closed vessel explosions of propane-air mixtures are reported, for systems with various initial concentrations, pressures and temperatures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.3 bar; T(0)=298-423 K). Experiments were performed in a spherical vessel (Φ=10 cm) with central ignition. The deflagration (severity) index K(G), calculated from experimental values of maximum rates of pressure rise is examined against the adiabatic deflagration index, K(G, ad), computed from normal burning velocities and peak explosion pressures. At constant temperature and fuel/oxygen ratio, both the maximum rates of pressure rise and the deflagration indices are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, the maximum rates of pressure rise and deflagration indices are slightly influenced by the initial temperature; some influence of the initial temperature on maximum rates of pressure rise is observed only for propane-air mixtures far from stoichiometric composition. The differentiated temperature influence on the normal burning velocities and the peak explosion pressures might explain this behaviour.

  13. Managing landscape disturbances to increase watershed infiltration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural land undergoing conversion to conventional urban development can drastically increase runoff and degrade water quality. A study of landscape management for improving watershed infiltration was conducted using readily available runoff data from experimental watersheds. This article focus...

  14. Chemical vapor infiltration using microwave energy

    DOEpatents

    Devlin, David J.; Currier, Robert P.; Laia, Jr., Joseph R.; Barbero, Robert S.

    1993-01-01

    A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.

  15. Dosimetric implications of the infiltrated injection

    SciTech Connect

    Castronovo, F.P.; McKusick, K.A.; Strauss, H.W.

    1984-01-01

    Following inadvertent infiltration of a radiopharmaceutical, there is variable and uncertain uptake in target tissue. Concomitantly, there is also a concern for the radiation dose to the infiltrated site. This investigation determined the clearance and radiation burdens from various radiopharmaceutical infiltrates in a rat model. Nine separate sites were studied for: Tc-99m microspheres; Tc-99m MDP; Ga-67 citrate; and Tl-201 chloride. Following sc injection on the shaven posteriors of anesthetized adult male Sprague-Dawley rats, gamma camera and computer data were collected up to 24 hours. The resulting data were expressed semilogarithmically as the mean (N = 9) of the ''% retained at site'' as a f(time) after injection. Nonparticulate agents showed a tri-exponential release pattern from each site, whereas the microspheres remained for an extended period of time. Using these pharma-cokinetic curves, the % remaining at each site for various times, and rems/mCi per lcc infiltrate was determined.

  16. Mathematical Analysis and Optimization of Infiltration Processes

    NASA Technical Reports Server (NTRS)

    Chang, H.-C.; Gottlieb, D.; Marion, M.; Sheldon, B. W.

    1997-01-01

    A variety of infiltration techniques can be used to fabricate solid materials, particularly composites. In general these processes can be described with at least one time dependent partial differential equation describing the evolution of the solid phase, coupled to one or more partial differential equations describing mass transport through a porous structure. This paper presents a detailed mathematical analysis of a relatively simple set of equations which is used to describe chemical vapor infiltration. The results demonstrate that the process is controlled by only two parameters, alpha and beta. The optimization problem associated with minimizing the infiltration time is also considered. Allowing alpha and beta to vary with time leads to significant reductions in the infiltration time, compared with the conventional case where alpha and beta are treated as constants.

  17. Counterflow diffusion flames of hydrogen, and hydrogen plus methane, ethylene, propane, and silane vs. air - Strain rates at extinction

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. Burton; Wilson, L. G.

    1991-01-01

    Five coaxial tubular opposed jet burners (OJBs) with tube diameter D(T) of 1.8-10 mm and 5 mm conical nozzles were used to form dish-shaped counterflow diffusion flames centered by opposing laminar jets of nitrogen and hydrocarbon-diluted H2 versus air in an argon-purged chamber at 1 atm. Area-averaged air jet velocities at blowoff of the central flame, U(air), characterized extinction of the airside flame as functions of input H2 concentration on the fuelside. A master plot of extensive U(air) data at blowoff versus D(T) shows that U(air) varies linearly with D(T). This and other data sets are used to find that nozzle OJB results for U(air)/diameter average 4.24 + or - 0.28 times larger than tubular OJB results for the same fuel compositions. Critical radial velocity gradients consistent with one-dimensional stagnation point boundary theory and with plug flow inputs are estimated. The results compare favorably with published numerical results based only on potential flow.

  18. Determination of air-kerma strength for the {sup 192}Ir GammaMedplus iX pulsed-dose-rate brachytherapy source

    SciTech Connect

    Riley, A. D.; Pike, T. L.; Micka, J. A.; Fulkerson, R. K.; DeWerd, L. A.

    2013-07-15

    Purpose: Pulsed-dose-rate (PDR) brachytherapy was originally proposed to combine the therapeutic advantages of high-dose-rate (HDR) and low-dose-rate brachytherapy. Though uncommon in the United States, several facilities employ pulsed-dose-rate brachytherapy in Europe and Canada. Currently, there is no air-kerma strength standard for PDR brachytherapy {sup 192}Ir sources traceable to the National Institute of Standards and Technology. Discrepancies in clinical measurements of the air-kerma strength of the PDR brachytherapy sources using HDR source-calibrated well chambers warrant further investigation.Methods: In this research, the air-kerma strength for an {sup 192}Ir PDR brachytherapy source was compared with the University of Wisconsin Accredited Dosimetry Calibration Laboratory transfer standard well chambers, the seven-distance technique [B. E. Rasmussen et al., 'The air-kerma strength standard for 192Ir HDR sources,' Med. Phys. 38, 6721-6729 (2011)], and the manufacturer's stated value. Radiochromic film and Monte Carlo techniques were also employed for comparison to the results of the measurements.Results: While the measurements using the seven-distance technique were within + 0.44% from the manufacturer's determination, there was a + 3.10% difference between the transfer standard well chamber measurements and the manufacturer's stated value. Results showed that the PDR brachytherapy source has geometric and thus radiological qualities that exhibit behaviors similar to a point source model in contrast to a conventional line source model.Conclusions: The resulting effect of the pointlike characteristics of the PDR brachytherapy source likely account for the differences observed between well chamber and in-air measurements.

  19. Nutrient transport and transformation beneath an infiltration basin

    USGS Publications Warehouse

    Sumner, D.M.; Rolston, D.E.; Bradner, L.A.

    1998-01-01

    Field experiments were conducted to examine nutrient transport and transformation beneath an infiltration basin used for the disposal of treated wastewater. Removal of nitrogen from infiltrating water by denitrification was negligible beneath the basin, probably because of subsurface aeration as a result of daily interruptions in basin loading. Retention of organic nitrogen in the upper 4.6 m of the unsaturated zone (water table depth of approximately 11 m) during basin loading resulted in concentrations of nitrate as much as 10 times that of the applied treated wastewater, following basin 'rest' periods of several weeks, which allowed time for mineralization and nitrification. Approximately 90% of the phosphorus in treated wastewater was removed within the upper 4.6 m of the subsurface, primarily by adsorption reactions, with abundant iron and aluminum oxyhydroxides occurring as soil coatings. A reduction in the flow rate of infiltrating water arriving at the water table may explain the accumulation of relatively coarse (>0.45 ??m), organic forms of nitrogen and phosphorus slightly below the water table. Mineralization and nitrification reactions at this second location of organic nitrogen accumulation contributed to concentrations of nitrate as much as three times that of the applied treated wastewater. Phosphorus, which accumulated below the water table, was immobilized by adsorption or precipitation reactions during basin rest periods.Field experiments were conducted to examine nutrient transport and transformation beneath an infiltration basin used for the disposal of treated wastewater. Removal of nitrogen from infiltrating water by denitrification was negligible beneath the basin, probably because of subsurface aeration as a result of daily interruptions in basin loading. Retention of organic nitrogen in the upper 4.6 m of the unsaturated zone (water table depth of approximately 11 m) during basin loading resulted in concentrations of nitrate as much as 10

  20. Climatic Forecasting of Net Infiltration at Yucca Mountain UsingAnalogue Meteorological Data

    SciTech Connect

    Faybishenko, Boris

    2005-12-22

    At Yucca Mountain, NV, future changes in climatic conditionswill probably alter net infiltration, drainage below the bottom of theevapotranspiration zone within the soil profile, or flow across theinterface between soil and the densely welded part of the Tiva CanyonTuff. The objectives of this study were to: (i) develop a semiempiricalmodel and forecast average net infiltration rates, using the limitedmeteorological data from analog meteorological stations, for interglacial(present day), and future monsoon, glacial transition, and glacialclimates over the Yucca Mountain region; and (ii) corroborate thecomputed net infiltration ratesby comparing them with the empiricallyand numerically determined groundwater recharge and percolation ratesthrough the unsaturated zone from published data. This study approachedcalculations of net infiltration, aridity, and precipitationeffectiveness indices using a modified Budyko's water-balance model, withreference-surface potential evapotranspiration determined from theradiation-based Penman formula. Results of calculations show that netinfiltration rates are expected to generally increase from thepresent-day climate to monsoon climate, to glacial transition climate,and then to the glacial climate, following a power law relationshipbetween net infiltration and precipitation. The forecasting resultsindicate the overlap between the ranges of net infiltration for differentclimates. Forecasting of net infiltration for different climate states issubject to numerous uncertainties associated with selecting climateanalog sites, using relatively short analog meteorological records,neglecting the effects of vegetation and surface runoff and run-on on alocal scale, as well as possible anthropogenically induced climatechanges.

  1. Detailed analysis of inflammatory cell infiltration in colorectal cancer

    PubMed Central

    Väyrynen, J P; Tuomisto, A; Klintrup, K; Mäkelä, J; Karttunen, T J; Mäkinen, M J

    2013-01-01

    Background: Higher-grade inflammatory infiltrate is a promising marker for better prognosis in colorectal cancer (CRC). However, the knowledge on the interrelationships between different inflammatory cells and classifications is fragmentary. Methods: We analysed the densities of eight types of inflammatory cells in a prospectively recruited group of 117 CRC patients and determined their interrelationships and contributions to Klintrup–Mäkinen (K–M) score of overall peritumoural inflammation. We characterised the inflammatory infiltrate in relation to stage and recurrences in 24-month follow-up. Results: There were high positive correlations between the inflammatory cell densities, with the exception of mast cells and CD1a+ immature dendritic cells. High K–M score associated with high peri- and intratumoural densities of CD3+, CD8+, CD68+, CD83+, and FoxP3+ cells and neutrophils. Advanced stage associated with low K–M score, as well as low CD3+, CD8+, CD83+, and FoxP3+ cell counts, of which low K–M score, low CD3+ T-cell count, and low FoxP3+ T-cell count were linked to higher recurrence rate. Conclusion: The density of CRC inflammatory infiltrate declines as stage advances. Especially, low K–M score and low T-cell counts predict higher recurrence rate. The high positive correlations between the individual inflammatory markers support the value of overall inflammatory reaction scoring. PMID:24008661

  2. Host cell infiltration into PDT-treated tumor

    NASA Astrophysics Data System (ADS)

    Korbelik, Mladen; Krosl, Gorazd; Dougherty, Graeme J.; Chaplin, David J.

    1992-06-01

    C3H mice bearing SCCVII squamous cell carcinoma were treated with photodynamic therapy (PDT) 24 hours after receiving Photofrin (25 mg/kg, i.v.). Single cell suspensions obtained by the enzymatic digestion of tumors excised either 30 minutes or 4 hours after PDT were analyzed for the content of host immune cells and colony forming ability of malignant cells. The results were compared to the data obtained with non-treated tumors. It is shown that there is a marked increase in the content of cells expressing Mac-1 (monocytes/macrophages or granulocytes) in the tumor 30 minutes post PDT, while a high level of other leucocytes are found within the tumors by 4 hours after PDT. As elaborated in Discussion, the infiltration rate of host immune cells, dying of malignant tumor cells, and yet unknown death rate of host cells originally present in PDT treated tumor occurring concomitantly during this time period complicates this analysis. The results of this study suggest a massive infiltration of macrophages and other leucocytes in PDT treated SCCVII tumor, supporting the suggestion that a potent immune reaction is one of the main characteristics of PDT action in solid tumors. It remains to be determined to what extent is the activity of tumor infiltrating immune cells responsible for its eradication by PDT.

  3. Effects of H2O, CO2, and N2 air contaminants on critical airside strain rates for extinction of hydrogen-air counterflow diffusion flames

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. B.; Wilson, L. G.; Guerra, Rosemary

    1989-01-01

    Dish-shaped counterflow diffusion flames centered by opposing laminar jets of H2 and clean and contaminant O2/N2 mixtures in an argon bath at 1 atm were used to study the effects of contaminants on critical airside strain. The jet velocities for both flame extinction and restoration are found for a wide range of contaminant and O2 concentrations in the air jet. The tests are also conducted for a variety of input H2 concentrations. The results are compared with those from several other studies.

  4. Real Time Electrical Monittoring of the Soil Infiltration

    NASA Astrophysics Data System (ADS)

    Losinno, B.; Sainato, C. M.

    2012-12-01

    Infiltration into the soil plays a key role in the agricultural field. Standard methodologies to determine basic infiltration rate are altered by the presence of preferential flow pathways in the soil. At intensive livestock farms, previous studies showed that in areas with high stocking rates and consequently high levels of trampling, both the basic infiltration rate measured in the field as a field such as saturated hydraulic conductivity (Ks) measured in laboratory had values significantly lower than those obtained in the areas without animals. Therefore, the evaluation of the infiltration process as an entry of pollutants into the profile is of importance in determining indicators of vulnerability to groundwater contamination. Geoelectrical methodology was used in combination with tracers to study the movement of water flow. A salty solution was used as tracer as it progresses along the profile. It is assumed that the water flow rate is similar to that of the applied solution. Geolelctric surveys can measure the apparent electrical resistivity inverse of the ECa, apparent electrical conductivity) in real time and thus determine the direction and speed of water flow through the profile. The aim of this study was to detect and characterize potential preferential flow pathways, comparing sectors where the high trampling by animals has generated high compaction, with areas without animals. We chose two sites: one located under high trampling at path between the pens of a feedlot placed at a lower position which receives runoff from feedlots. The background site was chosen at a pasture plot, with sporadic presence of animals. The soil is silty-loamy. In each of the sites sprinkler irrigation was performed in a square of 4 m x 4 m with saline solution of potassium bromide (concentration 5 g / l). After the irrigation, dipole - dipole survey was done with a line of stainless steel electrodes spaced 20 cm. while the flow is penetrating into the ground. Two dimension

  5. Infiltrating lipomatosis of the face: A case series

    PubMed Central

    Urs, Aadithya B.; Augustine, Jeyaseelan; Kumar, Priya; Arora, Shelly; Aggarwal, Neha; Sultana, Neha

    2013-01-01

    Infiltrating lipomatosis of the face is a very rare entity which is characterized by the collection of non-encapsulated mature adipocytes infiltrating local tissues, resulting in craniofacial deformities. Psychomotor development of the patients is normal, esthetics often being the primary concern to seek treatment. The presentation is always unilateral with hypertrophy of hard and soft structures on the affected side of the face. The pathogenesis of the condition is unclear. This condition shows a wide phenotypic range, uncertain prognosis with high rates of recurrence after surgery, and variable post-op cosmetic improvement. The condition shows no gender predilection, with most of the cases presenting in and beyond the second decade of life. Here, we present a series of four cases presenting in varying age groups with history of recurrence in three cases. PMID:23633877

  6. Anesthetic efficacy of an infiltration in mandibular anterior teeth following an inferior alveolar nerve block.

    PubMed Central

    Clark, Kenneth; Reader, Al; Beck, Mike; Meyers, William J.

    2002-01-01

    The purpose of this prospective, randomized, blinded study was to measure the degree of pulpal anesthesia obtained with an inferior alveolar nerve (IAN) block followed by an infiltration in mandibular anterior teeth. Through use of a repeated-measures design, 40 patients randomly received 3 injection combinations at 3 separate appointments: an IAN block followed by a mock lingual infiltration and a mock labial infiltration, an IAN block followed by a mock lingual infiltration and a labial infiltration, and an IAN block followed by a mock labial infiltration and a lingual infiltration. Each IAN block used 3.6 mL of 2% lidocaine with 1:100,000 epinephrine, and each infiltration used 1.8 mL of 2% lidocaine with 1:100,000 epinephrine administered over the lateral incisor apex. Mandibular anterior teeth were blindly pulp tested at 2-minute cycles for 60 minutes following the IAN-infiltration injections. No response from the patient to the maximum output (80 reading) of the pulp tester was used as the criterion for pulpal anesthesia. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes and the 80 reading was sustained for 60 minutes. Anesthesia was considered a failure if 2 consecutive 80 readings were not obtained during the 60 minutes. The results of this study showed that 100% of the patients had lip numbness with all IAN blocks. For the lateral incisor, the success rate of the IAN block alone was 40% and the failure rate was 30%. For the IAN block plus labial infiltration, the success rate was 62% and the failure rate was 12% for the lateral incisor. There was a significant difference (P < .05) between the IAN block alone and the IAN block plus labial infiltration. In conclusion, a labial infiltration, over the lateral incisor apex, of 1.8 mL of 2% lidocaine with 1:100,000 epinephrine following an IAN block significantly improved pulpal anesthesia for the lateral incisor compared with the IAN block alone. PMID:15384292

  7. The effects of indoor particle exposure on blood pressure and heart rate among young adults: An air filtration-based intervention study

    NASA Astrophysics Data System (ADS)

    Lin, Lian-Yu; Chen, Hua-Wei; Su, Te-Li; Hong, Gui-Bing; Huang, Li-Chu; Chuang, Kai-Jen

    2011-10-01

    This study aims to evaluate whether air filtration can modify the effect of indoor particles on blood pressure (BP) and heart rate (HR) in a young, healthy population. We recruited 60 students to participate in a study of multiple, prolonged exposures to either particle-filtered or non-filtered indoor air. We made four home visits in which we took continuous 48-hour measurements of systolic BP (SBP), diastolic BP (DBP), and HR in each participant. Particulate matter less than 2.5 μm in diameter (PM 2.5) and total volatile organic compounds (VOCs) were measured at each participant's home. We used mixed-effects models to associate BP and HR with indoor particles and total VOCs, which were averaged over 1-hour to 8-hour periods prior to physiological measurements. We found that the mean values for indoor PM 2.5 exposures at 1-hour to 4-hour were associated with an elevation in SBP, DBP and HR. The effects of indoor PM 2.5 on BP and HR were greatest during the visits without air filtration. During visits with air filtration, participants showed no significant change in BP and HR in response to indoor PM 2.5 exposure. We concluded that air filtration can reduce indoor PM 2.5 concentrations and modify the effect of PM 2.5 on BP and HR in a healthy, young population.

  8. Infiltration and quality of water for two arroyo channels, Albuquerque, New Mexico, 1988-92

    USGS Publications Warehouse

    Thomas, Carole L.

    1995-01-01

    Selected reaches of Grant Line Arroyo and Tijeras Arroyo in Albuquerque, New Mexico, were studied to collect information about the amount and quality of infiltration through arroyo channels. Infiltration rate was calculated for selected reaches of Grant Line Arroyo and Tijeras Arroyo based on instantaneous streamflow-loss volumes, wetted channel area, and instantaneous evaporation rates measured during 1988-92. Infiltration rates at Grant Line Arroyo ranged from 0.0 to 0.6 foot per day, and at Tijeras Arroyo from 2.28 to 30 feet per day. The evaporation rate ranged from one-tenth of 1 percent to 2 percent of the infiltration rate. Infiltration rates differed with the location of the reach isolated for measurement and with the time of day of the infiltration-rate measurement. Differences in intrinsic permeability of the sediments may be the most important factor affecting spatial variations in infiltration. The most important factor affecting temporal variations in infiltration may be the temperature of the water and sediment where infiltration occurs. Annual evaporation rates were greatest over saturated stream sediments and ranged from 802 to 1,025 millimeters per year or from 31.57 to 40.35 inches per year. Annual evaporation rates were least over unsaturated, unvegetated soil and ranged from 174 to 291 millimeters per year or from 6.85 to 11.46 inches per year. Annual evapotranspiration rates over grasses or shrubs or both were about one-half the rates over saturated stream sediments. Rates were similar for Grant Line and Tijeras Arroyos. The land- surface vegetation, availability of water at the land surface, availability of energy to enable a change of state from water to vapor, existence of a vapor concentration gradient, and a turbulent atmosphere to carry the vapor away may be the factors that determine the amount of evaporation and evapotranspiration. Water in Grant Line Arroyo and Tijeras Arroyo met U. S. Environmental Protection Agency drinking

  9. Overcoming the difficulties in collecting apoplastic fluid from rice leaves by the infiltration-centrifugation method.

    PubMed

    Nouchi, Isamu; Hayashi, Kentaro; Hiradate, Syuntaro; Ishikawa, Satoru; Fukuoka, Minehiko; Chen, Charles P; Kobayashi, Kazuhiko

    2012-09-01

    Physiological and biochemical studies on the leaf apoplast have been facilitated by the use of the infiltration-centrifugation technique to collect intercellular washing fluid (IWF). However, this technique has been difficult to implement in rice (Oryza sativa L.) for various reasons. We compared the collection efficiency of leaf IWF between two types of rice varieties (Indica and Japonica), as well as between rice and other species (spinach, snap bean and wheat). Although the extraction of IWF in most species took only 2-3 min, it took up to 35 min in rice. The difficulty in infiltration with rice was ascribed to the small stomatal aperture and hydrophobicity of the leaves. In this study, we have established an improved method for collecting IWF and determining the apoplastic air and water volumes in rice leaves. We have shortened the infiltration time to 8 min via the following improvements: (i) infiltration under outdoor shade in the daytime to prevent stomatal closure and a rise in temperature of the infiltration medium; (ii) soaking of leaves in a surfactant solution to decrease the leaf hydrophobicity; and (iii) continuous pressurization using a sealant injector to facilitate the infiltration. The rapid collection of IWF achieved using this technique will facilitate study of the leaf apoplast in rice.

  10. Expression of JMJD2A in infiltrating duct carcinoma was markedly higher than fibroadenoma, and associated with expression of ARHI, p53 and ER in infiltrating duct carcinoma.

    PubMed

    Li, Bei-Xu; Li, Jia; Luo, Cheng-Liang; Zhang, Ming-Chang; Li, Hui; Li, Li-Liang; Xu, Hong-Fei; Shen, Yi-Wen; Xue, Ai-Min; Zhao, Zi-Qin

    2013-03-01

    Jumonji Domain Containing 2A (JMJD2A) may be a cancer-associated gene involved in human breast cancer. With a view to investigating expression of JMJD2A in human breast cancer and benign lesion tissues as well as relationship between JMJD2A and tumor related proteins, histological and immunohistochemical analysis, Western blot and quantitative real-time PCR in infiltrating duct carcinoma and fibroadenoma for JMJD2A and immunohistochemical analysis and quantitative real-time PCR in infiltrating duct carcinoma for tumor related proteins (ARHI, p53, ER, PR and CerbB-2) were performed. Histological examination validated the clinical diagnosis. The JMJD2A positive rate of infiltrating duct carcinoma was significantly higher than fibroadenoma by immunohistochemical analysis. The mean optical density of JMJD2A in infiltrating duct carcinoma was higher than fibroadenoma by western blot. JMJD2A mRNA level in infiltrating duct carcinoma was higher than fibroadenoma by quantitative real-time PCR. Spearman correlation analysis revealed that the expression of JMJD2A was associated with ARHI, p53 and ER from immunohistochemical results respectively. Pearson correlation analysis revealed that the expression of JMJD2A was associated with ARHI, p53 and ER from quantitative real-time PCR results respectively. Expression of JMJD2A in infiltrating duct carcinoma was higher, and associated with ARHI, p53 and ER. The results may take JMJD2A as a potential diagnostic and therapeutic target in human breast cancer.

  11. The study of mercury exchange rate between air and soil surface in Hongfeng reservoir region, Guizhou, PR China

    NASA Astrophysics Data System (ADS)

    Wang, S.; Feng, X.; Qiu, G.

    2003-05-01

    In summer of 2002, we measured the exchange flux of mercury between air and soil surface using the method of Dynamic Flux Chamber (DFC) in Hongfeng lake region. At the same time, we recorded meteorological parameters such as air temperature, soil temperature, wind speed and solar radiation using a multi-function mini-weather station (global water III). Soil, moss and fertilizer samples in study area were also collected. The Hg fluxes of air/soil surface rangeed from -11.0ng m^{-2} h^{-1} to 219.0ng m^{-2}h^{-1}, averaged at 29.2 ng m^{-2} h^{-1} (n = 508). The data show that the exchange of mercury is bi-direction between air and soit surface: namely both emission and deposition of mercury occurs, but Hg emission is much more frequent than deposition process (n_{deposition} =3,n_{emission}= 505). The average mercury content in soil, moss, fertilizer sample are 249.9± 24.1ng/g (n=3), 450.4 ± 64.6ng/g (n=2), 53.4ng/g (n= 1) respectively.

  12. Sorptivity and liquid infiltration into dry soil

    NASA Astrophysics Data System (ADS)

    Culligan, Patricia J.; Ivanov, Vladimir; Germaine, John T.

    2005-10-01

    The sorptivity S quantifies the effect of capillarity on liquid movement in a porous material. For liquid infiltration into an initially dry material, S is a parameter that is contingent on both liquid and material properties as well as the maximum liquid content behind the infiltrating front, θm. Scaling analyses are used to derive a dimensionless, intrinsic sorptivity S∗ that is constant for different liquids, Miller-similar materials and different values of θm. The analyses confirm that S is dependent on β1/2, where β = cos ϕ is a measure of the wettability of the liquid. They also indicate a power law relationship between S and Se(av), the average liquid saturation behind the infiltrating front. Seventeen water and eleven Soltrol 220 horizontal infiltration experiments are reported in uniform, dry sand. Test results show that water is partially wetting in the sand. They also confirm that S∝Se(av)d, where d = 3.2 for the experimental conditions. The usefulness of a general, dimensionless Boltzmann variable is demonstrated to normalize infiltration profiles for the different liquids. An approximate method for sorptivity calculation is shown to provide an accurate estimate of S∗.

  13. Greatly Increased Toughness of Infiltrated Spider Silk

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Mo; Pippel, Eckhard; Gösele, Ulrich; Dresbach, Christian; Qin, Yong; Chandran, C. Vinod; Bräuniger, Thomas; Hause, Gerd; Knez, Mato

    2009-04-01

    In nature, tiny amounts of inorganic impurities, such as metals, are incorporated in the protein structures of some biomaterials and lead to unusual mechanical properties of those materials. A desire to produce these biomimicking new materials has stimulated materials scientists, and diverse approaches have been attempted. In contrast, research to improve the mechanical properties of biomaterials themselves by direct metal incorporation into inner protein structures has rarely been tried because of the difficulty of developing a method that can infiltrate metals into biomaterials, resulting in a metal-incorporated protein matrix. We demonstrated that metals can be intentionally infiltrated into inner protein structures of biomaterials through multiple pulsed vapor-phase infiltration performed with equipment conventionally used for atomic layer deposition (ALD). We infiltrated zinc (Zn), titanium (Ti), or aluminum (Al), combined with water from corresponding ALD precursors, into spider dragline silks and observed greatly improved toughness of the resulting silks. The presence of the infiltrated metals such as Al or Ti was verified by energy-dispersive x-ray (EDX) and nuclear magnetic resonance spectra measured inside the treated silks. This result of enhanced toughness of spider silk could potentially serve as a model for a more general approach to enhance the strength and toughness of other biomaterials.

  14. The inflammatory infiltrate of melanocytic nevus.

    PubMed

    Fernandez-Flores, Angel; Saeb-Lima, Marcela

    2014-01-01

    Melanocytic nevi are frequently accompanied by inflammatory cells of different types, in varied amounts and distributed in different patterns. In the current report, we review the knowledge on inflammation seen in different types of melanocytic nevi. As an additional contribution, we studied the lymphocytic inflammatory component of Duperrat nevus, as well as the cytotoxic component of Sutton nevus, two contributions that we have not found in the literature. We conclude that: (a) Duperrat nevus has a mixed inflammatory reaction that includes histiocytes, foreign-body multinucleated giant cells, polymorphonuclears, lymphocytes (predominantly CD4+) and plasma cells (commonly abundant); (b) common melanocytic nevi with reactive inflammatory infiltrate usually show a CD4+ predominant population; (c) Meyerson nevus commonly shows an inflammatory infiltrate mainly made up of CD4+ T-cells; (d) Sutton nevus with halo phenomenon is accompanied by a dense inflammatory infiltrate with lymphocytes in a CD4:CD8 ratio varying from 1:1 to 1:3 and in which most of the CD8+ T-cells do not express cytotoxic markers; (e) Wiesner nevus commonly shows a spare lymphocytic infiltrate but the nature of the infiltrate has not yet been investigated.

  15. Incorporating infiltration modelling in urban flood management

    NASA Astrophysics Data System (ADS)

    Jumadar, A. S.; Pathirana, A.; Gersonius, B.; Zevenbergen, C.

    2008-06-01

    Increasing frequency and intensity of flood events in urban areas can be linked to increase in impervious area due to urbanization, exacerbated by climate change. The established approach of conveying storm water by conventional drainage systems has contributed to magnification of runoff volume and peak flows beyond those of undeveloped catchments. Furthermore, the continuous upgrading of such conventional systems is costly and unsustainable in the long term. Sustainable drainage systems aim at addressing the adverse effects associated with conventional systems, by mimicking the natural drainage processes, encouraging infiltration and storage of storm water. In this study we model one of the key components of SuDS, the infiltration basins, in order to assert the benefits of the approach. Infiltration modelling was incorporated in the detention storage unit within the one-dimensional urban storm water management model, EPA-SWMM 5.0. By introduction of infiltration modelling in the storage, the flow attenuation performance of the unit was considerably improved. The study also examines the catchment scale impact of both source and regional control storage/infiltration systems. Based on the findings of two case study areas modelled with the proposed options, it was observed that source control systems have a greater and much more natural impact at a catchment level, with respect to flow attenuation, compared to regional control systems of which capacity is equivalent to the sum of source control capacity at the catchment.

  16. Estimating an overall infiltration value in an urbanized watershed using high-resolution satellite images and ground measurements 1934

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rain water infiltration is part of the water cycle and is strongly influenced by human activities, such as urban growth. Changes in infiltration rates due to urbanization can affect storm water runoff, soil moisture and groundwater recharge. This is of particular concern in areas of rapid urbanizati...

  17. Single-zone stack-dominated infiltration modeling

    SciTech Connect

    Sherman, M.H.

    1991-09-01

    Simplified, physical models for calculating infiltration in a single zone, usually calculate the air flows from the natural driving forces separately and then combine them. For most purposes -- especially minimum ventilation or energy considerations -- the stack effect dominates and total ventilation can be calculated by treating other effects (i.e., wind and small fans) as perturbations, using superposition techniques. The stack effect is caused by differences in density between indoor and outdoor air, normally attributable to the indoor-outdoor temperature difference. This report derives an exact, but practical, expression for calculating the stack effect from the air densities and leakage distribution using the power law formulation of envelope leakage. The neutral height -- the height at which there is no stack-related indoor-outdoor pressure difference -- is a key intermediate in stack modeling. This report defines a computable parameter called stack height, which contains all of the leakage distribution information necessary for estimating stack flows, thus freeing the model from specific assumptions (e.g., that the leakage is separable into evenly distributed floor, wall, and ceiling components). Example calculations including comparisons with other models, as well as validations using measured data from dwellings, are also presented. The dimensionless neutral level, which is related to the neutral height, is often used as an indicator of leakage distribution and in superposition. Its definition and role in these regards are discussed in detail. The more exact formulation is then used to analyze the simple box cases normally assumed in infiltration modeling and other approximations. Measured ventilation data will be used to infer leakage distributions and neutral levels as well as for example calculations.

  18. Sensor for Individual Burner Control of Coal Firing Rate, Fuel-Air Ratio and Coal Fineness Correlation

    SciTech Connect

    R. Demler

    2006-04-01

    Accurate, cost-efficient monitoring instrumentation has long been considered essential to the operation of power plants. Nonetheless, for the monitoring of coal flow, such instrumentation has been sorely lacking and technically difficult to achieve. With more than half of the electrical power in the United States currently supplied by coal, energy generated by this resource is critical to the US economy. The demand for improvement in this area has only increased as a result of the following two situations: First, deregulation has produced a heightened demand for both reduced electrical cost and improved grid connectivity. Second, environmental concerns have simultaneously resulted in a need for both increased efficiency and reduced carbon and NOx emissions. A potential approach to addressing both these needs would be improvement in the area of combustion control. This would result in a better heat rate, reduced unburned carbon in ash, and reduced NOx emissions. However, before feedback control can be implemented, the ability to monitor coal flow to the burners in real-time must be established. While there are several ''commercially available'' products for real-time coal flow measurement, power plant personnel are highly skeptical about the accuracy and longevity of these systems in their current state of development. In fact, following several demonstration projects of in-situ coal flow measurement systems in full scale utility boilers, it became obvious that there were still many unknown influences on these instruments during field applications. Due to the operational environment of the power plant, it has been difficult if not impossible to sort out what parameters could be influencing the various probe technologies. Additionally, it has been recognized for some time that little is known regarding the performance of coal flow splitters, even where rifflers are employed. Often the coal flow distribution from these splitters remains mal-distributed. There have

  19. Synthesis of active carbon-based catalysts by chemical vapor infiltration for nitrogen oxide conversion.

    PubMed

    Busch, Martin; Bergmann, Ulf; Sager, Uta; Schmidt, Wolfgang; Schmidt, Frank; Notthoff, Christian; Atakan, Burak; Winterer, Markus

    2011-09-01

    Direct reduction of nitrogen oxides is still a challenge. Strong efforts have been made in developing noble and transition metal catalysts on microporous support materials such as active carbons or zeolites. However, the required activation energy and low conversion rates still limit its breakthrough. Furthermore, infiltration of such microporous matrix materials is commonly performed by wet chemistry routes. Deep infiltration and homogeneous precursor distribution are often challenging due to precursor viscosity or electrostatic shielding and may be inhibited by pore clogging. Gas phase infiltration, as an alternative, can resolve viscosity issues and may contribute to homogeneous infiltration of precursors. In the present work new catalysts based on active carbon substrates were synthesized via chemical vapor infiltration. Iron oxide nano clusters were deposited in the microporous matrix material. Detailed investigation of produced catalysts included nitrogen oxide adsorption, X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Catalytic activity was studied in a recycle flow reactor by time-resolved mass spectrometry at a temperature of 423 K. The infiltrated active carbons showed very homogeneous deposition of iron oxide nano clusters in the range of below 12 to 19 nm, depending on the amount of infiltrated precursor. The specific surface area was not excessively reduced, nor was the pore size distribution changed compared to the original substrate. Catalytic nitrogen oxides conversion was detected at temperatures as low as 423 K.

  20. [Effects of rainfall intensity on rainfall infiltration and redistribution in soil on Loess slope land].

    PubMed

    Li, Yi; Shao, Ming'an

    2006-12-01

    With simulation test, this paper studied the patterns of rainfall infiltration and redistribution in soil on typical Loess slope land, and analyzed the quantitative relations between the infiltration and redistribution and the movement of soil water and mass, with rainfall intensity as the main affecting factor. The results showed that rainfall intensity had significant effects on the rainfall infiltration and water redistribution in soil, and the microcosmic movement of soil water. The larger the rainfall intensity, the deeper the wetting front of rainfall infiltration and redistribution was, and the wetting front of soil water redistribution had a slower increase velocity than that of rainfall infiltration. The power function of the wetting front with time, and also with rainfall intensity, was fitted well. There was also a quantitative relation between the wetting front of rainfall redistribution and the duration of rainfall. The larger the rainfall intensity, the higher the initial and steady infiltration rates were, and the cumulative infiltration increased faster with time. Moreover, the larger the rainfall intensity, the smaller the wetting front difference was at the top and the end of the slope. With the larger rainfall intensity, both the difference of soil water content and its descending trend between soil layers became more obvious during the redistribution process on slope land.

  1. The heterogeneity of meningioma revealed by multiparameter analysis: infiltrative and non-infiltrative clinical phenotypes.

    PubMed

    Gay, Emmanuel; Lages, Elodie; Ramus, Claire; Guttin, Audrey; El Atifi, Michèle; Dupré, Isabelle; Bouamrani, Ali; Salon, Caroline; Ratel, David; Wion, Didier; Berger, François; Issartel, Jean-Paul

    2011-05-01

    Tumor invasion or infiltration of adjacent tissues is the source of clinical challenges in diagnosis as well as prevention and treatment. Among brain tumors, infiltration of the adjacent tissues with diverse pleiotropic mechanisms is frequently encountered in benign meningiomas. We assessed whether a multiparametric analysis of meningiomas based on data from both clinical observations and molecular analyses could provide a consistent and accurate appraisal of invasive and infiltrative phenotypes and help determine the diagnosis of these tumors. Tissue analyses of 37 meningiomas combined enzyme-linked immunosorbent assay (ELISA) and surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) assays of two different protein biomarkers (thrombospondin 1 and a phosphorylated form of vimentin) as well as gene expression analyses with oligonucleotide micro-arrays. Up to four different clinical and molecular parameters were then examined for tumor classification. From this study, we were able to cluster 36 out of the 37 tumors into two different subsets corresponding to infiltrative/invasive and non-infiltrative tumors. In addition, meningiomas that invade brain and those that infiltrate the neighboring skull bone exhibited no distinguishable molecular features. Our multi-parameter analysis that combines clinical data, transcriptomic and molecular assays clearly reveals the heterogeneity of meningiomas and distinguishes the intrinsically infiltrative/invasive tumors from the non-infiltrative meningiomas.

  2. Movement of water infiltrated from a recharge basin to wells

    USGS Publications Warehouse

    O'Leary, David R.; Izbicki, John A.; Moran, Jean E.; Meeth, Tanya; Nakagawa, Brandon; Metzger, Loren; Bonds, Chris; Singleton, Michael J.

    2012-01-01

    Local surface water and stormflow were infiltrated intermittently from a 40-ha basin between September 2003 and September 2007 to determine the feasibility of recharging alluvial aquifers pumped for public supply, near Stockton, California. Infiltration of water produced a pressure response that propagated through unconsolidated alluvial-fan deposits to 125 m below land surface (bls) in 5 d and through deeper, more consolidated alluvial deposits to 194 m bls in 25 d, resulting in increased water levels in nearby monitoring wells. The top of the saturated zone near the basin fluctuates seasonally from depths of about 15 to 20 m. Since the start of recharge, water infiltrated from the basin has reached depths as great as 165 m bls. On the basis of sulfur hexafluoride tracer test data, basin water moved downward through the saturated alluvial deposits until reaching more permeable zones about 110 m bls. Once reaching these permeable zones, water moved rapidly to nearby pumping wells at rates as high as 13 m/d. Flow to wells through highly permeable material was confirmed on the basis of flowmeter logging, and simulated numerically using a two-dimensional radial groundwater flow model. Arsenic concentrations increased slightly as a result of recharge from 2 to 6 μg/L immediately below the basin. Although few water-quality issues were identified during sample collection, high groundwater velocities and short travel times to nearby wells may have implications for groundwater management at this and at other sites in heterogeneous alluvial aquifers.

  3. Movement of water infiltrated from a recharge basin to wells.

    PubMed

    O'Leary, David R; Izbicki, John A; Moran, Jean E; Meeth, Tanya; Nakagawa, Brandon; Metzger, Loren; Bonds, Chris; Singleton, Michael J

    2012-01-01

    Local surface water and stormflow were infiltrated intermittently from a 40-ha basin between September 2003 and September 2007 to determine the feasibility of recharging alluvial aquifers pumped for public supply, near Stockton, California. Infiltration of water produced a pressure response that propagated through unconsolidated alluvial-fan deposits to 125 m below land surface (bls) in 5 d and through deeper, more consolidated alluvial deposits to 194 m bls in 25 d, resulting in increased water levels in nearby monitoring wells. The top of the saturated zone near the basin fluctuates seasonally from depths of about 15 to 20 m. Since the start of recharge, water infiltrated from the basin has reached depths as great as 165 m bls. On the basis of sulfur hexafluoride tracer test data, basin water moved downward through the saturated alluvial deposits until reaching more permeable zones about 110 m bls. Once reaching these permeable zones, water moved rapidly to nearby pumping wells at rates as high as 13 m/d. Flow to wells through highly permeable material was confirmed on the basis of flowmeter logging, and simulated numerically using a two-dimensional radial groundwater flow model. Arsenic concentrations increased slightly as a result of recharge from 2 to 6 µg/L immediately below the basin. Although few water-quality issues were identified during sample collection, high groundwater velocities and short travel times to nearby wells may have implications for groundwater management at this and at other sites in heterogeneous alluvial aquifers.

  4. Epinephrine Affects Pharmacokinetics of Ropivacaine Infiltrated Into Palate.

    PubMed

    Yamashiro, Mikiko; Hashimoto, Shuichi; Yasuda, Asako; Sunada, Katsuhisa

    2016-01-01

    Pulpal anesthesia success rates for ropivacaine following maxillary infiltration anesthesia seem to be low. We investigated the hypothesis that the addition of epinephrine would affect the pharmacokinetics of ropivacaine by retaining ropivacaine in the mucosa of the injected area through the time-dependent distribution of ropivacaine in the rat maxilla and serum following maxillary infiltration anesthesia using (3)H-labeled ropivacaine. We then examined the vasoactivity of ropivacaine with or without epinephrine on local peripheral blood flow. The addition of epinephrine to ropivacaine increased ropivacaine concentrations in the palatal mucosa and adjacent maxilla by more than 3 times that of plain ropivacaine at 20 minutes. By observing the autoradiogram of (3)H-ropivacaine, plain ropivacaine in the maxilla was remarkably reduced 20 minutes after injection. However, it was definitely retained in the palatal mucosa, hard palate, adjacent maxilla, and maxillary nerve after the administration with epinephrine. Ropivacaine with epinephrine significantly decreased labial blood flow. This study suggests that 10 μg/mL epinephrine added to 0.5% ropivacaine could improve anesthetic efficacy and duration for maxillary infiltration anesthesia over plain ropivacaine.

  5. Epinephrine Affects Pharmacokinetics of Ropivacaine Infiltrated Into Palate

    PubMed Central

    Yamashiro, Mikiko; Hashimoto, Shuichi; Yasuda, Asako; Sunada, Katsuhisa

    2016-01-01

    Pulpal anesthesia success rates for ropivacaine following maxillary infiltration anesthesia seem to be low. We investigated the hypothesis that the addition of epinephrine would affect the pharmacokinetics of ropivacaine by retaining ropivacaine in the mucosa of the injected area through the time-dependent distribution of ropivacaine in the rat maxilla and serum following maxillary infiltration anesthesia using 3H-labeled ropivacaine. We then examined the vasoactivity of ropivacaine with or without epinephrine on local peripheral blood flow. The addition of epinephrine to ropivacaine increased ropivacaine concentrations in the palatal mucosa and adjacent maxilla by more than 3 times that of plain ropivacaine at 20 minutes. By observing the autoradiogram of 3H-ropivacaine, plain ropivacaine in the maxilla was remarkably reduced 20 minutes after injection. However, it was definitely retained in the palatal mucosa, hard palate, adjacent maxilla, and maxillary nerve after the administration with epinephrine. Ropivacaine with epinephrine significantly decreased labial blood flow. This study suggests that 10 μg/mL epinephrine added to 0.5% ropivacaine could improve anesthetic efficacy and duration for maxillary infiltration anesthesia over plain ropivacaine. PMID:27269664

  6. The effect of fission products on the rate of U3O8 formation in SIMFUEL oxidized in air at 250°C

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Won; McEachern, Rod J.; Taylor, Peter; Wood, Donald D.

    1996-06-01

    The effect of fission products on the rate of U3O8 formation was investigated by oxidizing UO2-based SIMFUEL (simulated high burnup nuclear fuel) and unirradiated UO2 fuel specimens in air at 250°C for different times (1-317 days). The progress of oxidation was monitored by X-ray diffraction, revealing that the rate of U3O8 formation declines with increasing burnup. An expression was derived to describe quantitatively the time for U3O8 powder formation as a function of simulated burnup. These findings were supported by additional isochronal oxidation experiments conducted between 200 and 300°C.

  7. Influence of the initial soil water content on Beerkan water infiltration experiments

    NASA Astrophysics Data System (ADS)

    Lassabatere, L.; Loizeau, S.; Angulo-Jaramillo, R.; Winiarski, T.; Rossier, Y.; Delolme, C.; Gaudet, J. P.

    2012-04-01

    Understanding and modeling of water flow in the vadose zone are important with regards water management and infiltration devices design. Water infiltration process clearly depends on initial soil water content, in particular for sandy soils with high organic matter content. This study investigates the influence of initial water content on water infiltration in a hydrophobic sandy soil and on the related derivation of hydraulic parameters using the BEST algorithm (Lassabatere et al., 2006). The studied sandy soil has a high total organic content decreasing from 3.5% (w/w) at the surface to 0.5% (w/w) below 1cm depth. The highest TOC at surface was due to the presence of a dense biofilm and resulted in a high surface hydrophobicity under dry conditions (low initial water contents). The water infiltration experiments consisted in infiltrating known volumes of water through a simple ring at null pressure head (Beerkan method). The infiltrations were performed during three successive days after a dry period with a storm event between the first and the second day (5 mm) and another between the second and the third day (35 mm). These events resulted in an increase in initial water contents, from less than 5% for the first day to around 10% for the last day. Experiments were performed for appropriate conditions for Beerkan experiments: initial water contents below 1/4 of the saturated water content and uniform water profile resulting from water redistribution after each rainfall event. The analysis of the infiltration data clearly highlights the strong effect of hydrophobicity. For the driest initial conditions (first day), infiltration rates increased with time, whereas they decreased with time for wetter conditions. Such a decrease agreed with the principles of water infiltration without hydrophobicity. In addition, total cumulative infiltrations were far higher for the wettest conditions. Regarding hydraulic characterization, only the data obtained during the last

  8. Influence of Lithology and Slope Gradient to Infiltration of the Mount Malabar, West Java

    NASA Astrophysics Data System (ADS)

    Pratama, A.; Irawan, D. E.; Susanto, A.; Ardi, R. D. W.

    2016-01-01

    Volcano is an area which serves as a catchment area for the lowlands. Ability of rock or weathered-soil to absorb the rain water depends on several things, such as lithology and large of slope. Different lithology has different characteristics, including in terms of porosity which is directly related to the ability of rock to store water. Characteristics of lithology in volcanic area can change rapidly, both vertically and laterally. Large of slope in volcanic area that change significantly also can affect the infiltration rate (the seepage of rain) in rock or weathered-soil. Therefore, the influence of lithology and large of slope to the infiltration rate should be proven to predict the infiltration zone in volcanic area. Observations has been conducted on the eastern slopes of Mount Malabar with an area 78 km2, at coordinates 7003'28.04" LS - 7010'32.05" LS and 107038'37.64" BT - 107041'50.6" BT. The infiltration rate observed on the weathered-soil using simple single infiltrometer made of PVC pipe 50 cm long, on March-April 2015. The measurement is carried out at several points where the weathered-rock result has been known, as much two times for different slope in each point. 26 measurement points have been obtained from different slopes and weathered-soil of different five-lithology. The results showed that the infiltration rate proportional to the percentage of rock porosity and large of slope. Infiltration rate sequence from the smallest to the greatest are weathered-soil andesites, basaltic andesite, laharic breccias, alteration of dacite, and pyroclastic breccias. The greatest infiltration rate obtained is 10.11 cm/minute in pyroclastic breccia with 25o slope, while the smallest is 0.0437 cm/minute in pyroclastic breccias with 4o slope.

  9. 40 CFR 35.927-1 - Infiltration/inflow analysis.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Infiltration/inflow analysis. 35.927-1... Infiltration/inflow analysis. (a) The infiltration/inflow analysis shall demonstrate the nonexistence or possible existence of excessive infiltration/inflow in the sewer system. The analysis should identify...

  10. Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

    PubMed

    Martens, D E; Nollen, E A; Hardeveld, M; Velden-de Groot, C A; Gooijer, C D; Beuvery, E C; Tramper, J

    1997-01-01

    The death rate of Vero cells grown on Cytodex-3 microcarrierswas studied as a function of the gas flow rate in a smallair-lift loop reactor. The death rate may be described byfirst-order death-rate kinetics. The first-order death-rateconstant as calculated from the decrease in viable cells, theincrease in dead cells and the increase in LDH activity islinear proportional to the gas flow rate, with a specifichypothetical killing volume in which all cells are killed ofabout 2.10(-3)m(3) liquid per m(3) of air bubbles.In addition, an experiment was conducted in the sameair-lift reactor with Vero cells grown inside porous Asahimicrocarriers. The specific hypothetical killing volumecalculated from this experiment has a value of 3.10(-4)m(3) liquid per m(3) of air bubbles, which shows thatthe porous microcarriers were at least in part able to protectthe cells against the detrimental hydrodynamic forcesgenerated by the bubbles.

  11. Improving the Quality of Student Ratings of Instruction: A Look at Two Strategies. AIR 1988 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Cook, Stuart S.

    The effect of rating scale format (behaviorally anchored rating scales (BARS) and Likert) and rater training on leniency and halo in student ratings of instruction was investigated. The subjects (N=269) were students enrolled in required courses at a graduate theological seminary in the southwestern United States. A repeated measures design…

  12. Opal photonic crystals infiltrated with chalcogenide glasses

    SciTech Connect

    Astratov, V. N.; Adawi, A. M.; Skolnick, M. S.; Tikhomirov, V. K.; Lyubin, V.; Lidzey, D. G.; Ariu, M.; Reynolds, A. L.

    2001-06-25

    Composite opal structures for nonlinear applications are obtained by infiltration with chalcogenide glasses As{sub 2}S{sub 3} and AsSe by precipitation from solution. Analysis of spatially resolved optical spectra reveals that the glass aggregates into submillimeter areas inside the opal. These areas exhibit large shifts in the optical stop bands by up to 80 nm, and by comparison with modelling are shown to have uniform glass filling factors of opal pores up to 40%. Characterization of the domain structure of the opals prior to infiltration by large area angle-resolved spectroscopy is an important step in the analysis of the properties of the infiltrated regions. {copyright} 2001 American Institute of Physics.

  13. Snowmelt rate dictates streamflow

    NASA Astrophysics Data System (ADS)

    Barnhart, Theodore B.; Molotch, Noah P.; Livneh, Ben; Harpold, Adrian A.; Knowles, John F.; Schneider, Dominik

    2016-08-01

    Declining mountain snowpack and earlier snowmelt across the western United States has implications for downstream communities. We present a possible mechanism linking snowmelt rate and streamflow generation using a gridded implementation of the Budyko framework. We computed an ensemble of Budyko streamflow anomalies (BSAs) using Variable Infiltration Capacity model-simulated evapotranspiration, potential evapotranspiration, and estimated precipitation at 1/16° resolution from 1950 to 2013. BSA was correlated with simulated baseflow efficiency (r2 = 0.64) and simulated snowmelt rate (r2 = 0.42). The strong correlation between snowmelt rate and baseflow efficiency (r2 = 0.73) links these relationships and supports a possible streamflow generation mechanism wherein greater snowmelt rates increase subsurface flow. Rapid snowmelt may thus bring the soil to field capacity, facilitating below-root zone percolation, streamflow, and a positive BSA. Previous works have shown that future increases in regional air temperature may lead to earlier, slower snowmelt and hence decreased streamflow production via the mechanism proposed by this work.

  14. Slow-light dispersion engineering of photonic crystal waveguides using selective microfluidic infiltration.

    PubMed

    Casas-Bedoya, A; Husko, C; Monat, C; Grillet, C; Gutman, N; Domachuk, P; Eggleton, B J

    2012-10-15

    We experimentally demonstrate dispersion engineering of slow light photonic crystal (PhC) waveguides using selective infiltration of the first two rows of air holes with high index ionic liquids. The infiltrated PhC waveguide exhibits a dispersion window of 3 nm with a nearly constant group velocity of ~c/80 that depends on the liquid physical properties. We investigate how the effective refractive index changes in time due to the dynamics of the liquids in the holes. This demonstration highlights the versatility, flexibility, and tunability offered by optofluidics in PhC circuits.

  15. A Simulation of the Effects of Varying Repetition Rate and Pulse Width of Nanosecond Discharges on Premixed Lean Methane-Air Combustion

    DOE PAGES

    Bak, Moon Soo; Cappelli, Mark A.

    2012-01-01

    Two-dimensional kinetic simulation has been carried out to investigate the effects of repetition rate and pulse width of nanosecond repetitively pulsed discharges on stabilizing premixed lean methane-air combustion. The repetition rate and pulse width are varied from 10 kHz to 50 kHz and from 9 ns to 2 ns while the total power is kept constant. The lower repetition rates provide larger amounts of radicals such as O, H, and OH. However, the effect on stabilization is found to be the same for all of the tested repetition rates. The shorter pulse width is found to favor the production of species in higher electronicmore » states, but the varying effects on stabilization are also found to be small. Our results indicate that the total deposited power is the critical element that determines the extent of stabilization over this range of discharge properties studied.« less

  16. An integrated evaluation study of the ventilation rate, the exposure and the indoor air quality in naturally ventilated classrooms in the Mediterranean region during spring.

    PubMed

    Dorizas, Paraskevi Vivian; Assimakopoulos, Margarita-Niki; Helmis, Constantinos; Santamouris, Mattheos

    2015-01-01

    Ventilation rates and indoor air pollutants have been extensively monitored in nine naturally ventilated primary schools of Athens, Greece during spring. The ventilation rates and pollutant levels were studied during the teaching and non-teaching periods and ventilation profiles were created for each of the schools. The median ventilation rates per school ranged between 0.7 and 8 ACH while the average ventilation rate in all schools (11.7l/s/p) was greater than the minimum recommended rates by ASHRAE for school classrooms. The average carbon dioxide (CO2) concentrations per school varied between 893 and 2082ppm, while the majority of the cases were slightly above the recommended limit values. CO2 concentrations were also positively correlated to the number of students and negatively correlated to the ventilation rates. Particles of several size ranges (PM10, PM5, PM2.5, PM1, PM0.5 and UFP) were also measured and analyzed. PM10 concentrations exceeded the recommended limit values by more than 10 times for the majority of the cases. There were also many cases that the PM2.5 concentrations exceeded their limit values. PM concentrations were significantly affected by the ventilation rates and the presence of students. All of the measured particle sizes were greater during teaching than the non-teaching hours. For most of the cases the indoor to outdoor (I/O) concentrations ratios of PM10 and PM2.5 were much greater than one, indicating that the indoor environment was being mostly affected by indoor sources instead of the outdoor air. Furthermore it was found that chalk and marker boards' usage significantly affect indoor pollutant concentrations. Overall, the measured levels of exposure were for most of the cases greater than the recommended guideline values due to the intense presence of indoor pollution sources, even though the ventilation rates were in general satisfactory.

  17. Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

  18. Summary of Simplified Two Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydrogen/Oxygen

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Molnar, Melissa

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (greater than l x 10(exp -20)) moles per cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T(sub 4)). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/Air fuel and for H2/O2. A similar correlation is also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T(sub 4)) as a function of overall fuel/air ratio, pressure and initial temperature (T(sub 3)). High values of the regression coefficient R squared are obtained.

  19. Assessment of organic compound exposures, thermal comfort parameters, and HVAC system-driven air exchange rates in public school portable classrooms in California

    SciTech Connect

    Shendell, Derek Garth

    2003-01-01

    The prevalence of prefabricated, portable classrooms (portables, relocatables, RCs) has increased due to class size reduction initiatives and limited resources. Classroom mechanical wall-mount heating, ventilation, and air conditioning (HVAC) systems may function improperly or not be maintained; lower ventilation rates may impact indoor air and environmental quality (IEQ). Materials in portables may off-gas volatile organic compounds (VOCs), including formaldehyde, as a function of age, temperature, and humidity. For a pilot study, public K-12 schools located in or serving target areas within five Los Angeles County communities were identified. In two communities where school districts (SD) consented, 1-3 randomly selected portables, one newer and one older, and one main building control classroom from each participating school were included. Sampling was conducted over a five-day school week in the cooling and heating seasons, or repeated twice in the cooling season. Measurements included passive samplers for VOCs, formaldehyde and acetaldehyde, and air exchange rate (AER) calculation; indoor air temperature and humidity; technician walk-through surveys; an interview questionnaire above HVAC system operation and maintenance (O and M). For an intervention study evaluating advanced HVAC technologies in comparison to the common conventional technology, and materials for source reduction of VOCs, four RC were manufactured and located in pairs at two schools in two recruited Northern California SD in different climate zones. RCs were built with the two HVAC systems, cabinetry and conduit for monitoring equipment, and standard or advanced interior finish materials. Each RC was its own control in a case-crossover design--HVAC systems alternately operated for 1-2 week intervals in the 2001-02 school year, with IEQ monitoring including aldehyde and indoor air temperature and humidity data. Measured classroom AER were low, formaldehyde concentrations were below the state

  20. Raman measurement of mixing and finite-rate chemistry in a supersonic hydrogen-air diffusion flame

    SciTech Connect

    Cheng, T.S.; Wehrmeyer, J.A.; Pitz, R.W. . Dept. of Mechanical Engineering); Jarrett, O. Jr.; Northam, G.B. . Langley Research Center)

    1994-10-01

    Ultraviolet (UV) spontaneous vibrational Raman scattering and laser-induced predissociative fluorescence (LIPF) from a KrF excimer laser are combined to simultaneously measure temperature, major species concentrations (H[sub 2], O[sub 2], N[sub 2], H[sub 2]O), and OH radical concentration in a supersonic lifted co-flowing hydrogen-air diffusion flame. The axisymmetric flame is formed when a sonic jet of hydrogen mixes with a Mach 2 annular jet of vitiated air. Mean and rms profiles of temperature, species concentrations, and mixture fraction are obtained throughout the supersonic flame. Simultaneous measurements of the chemical species and temperature are compared with frozen chemistry and equilibrium chemistry limits to assess the local state of the mixing and chemistry. Upstream of the lifted flame base, a very small amount of reaction occurs form mixing with hot vitiated air. Downstream of the lifted flame base, strong turbulent mixing leads to sub equilibrium values of temperature and OH concentration. Due to the interaction of velocity and temperature in supersonic compressible flames, the fluctuations of temperature and species concentrations are found to be higher than subsonic flames. Farther downstream, slow three-body recombination reactions result in super equilibrium OH concentrations that depress temperatures below their equilibrium values.

  1. Pressureless infiltration of aluminum metal-matrix composites

    SciTech Connect

    Kajikawa, Y.; Nukami, T.; Flemings, M.C.

    1995-08-01

    Pressureless infiltration of ceramic preforms by molten aluminum is described. The preforms are SiC with varying amounts of particulate Al, Ti, and Ni. Infiltrants employed are pure Al and Al-12.5 wt pct Si. It is shown that a pressure differential within the preform is required for infiltration, and measurements are made of pressure changes in the preforms during infiltration. Results indicate that atmospheric pressure is essential for infiltration but that capillarity may play a role as well.

  2. Combined geophysical methods for mapping infiltration pathways at the Aurora Water Aquifer recharge and recovery site

    NASA Astrophysics Data System (ADS)

    Jasper, Cameron A.

    Although aquifer recharge and recovery systems are a sustainable, decentralized, low cost, and low energy approach for the reclamation, treatment, and storage of post- treatment wastewater, they can suffer from poor infiltration rates and the development of a near-surface clogging layer within infiltration ponds. One such aquifer recharge and recovery system, the Aurora Water site in Colorado, U.S.A, functions at about 25% of its predicted capacity to recharge floodplain deposits by flooding infiltration ponds with post-treatment wastewater extracted from river bank aquifers along the South Platte River. The underwater self-potential method was developed to survey self-potential signals at the ground surface in a flooded infiltration pond for mapping infiltration pathways. A method for using heat as a groundwater tracer within the infiltration pond used an array of in situ high-resolution temperature sensing probes. Both relatively positive and negative underwater self-potential anomalies are consistent with observed recovery well pumping rates and specific discharge estimates from temperature data. Results from electrical resistivity tomography and electromagnetics surveys provide consistent electrical conductivity distributions associated with sediment textures. A lab method was developed for resistivity tests of near-surface sediment samples. Forward numerical modeling synthesizes the geophysical information to best match observed self- potential anomalies and provide permeability distributions, which is important for effective aquifer recharge and recovery system design, and optimization strategy development.

  3. Statistical Analysis of Meteorological Data to Assess Evapotranspiration and Infiltration at the Rifle Site, CO, USA

    NASA Astrophysics Data System (ADS)

    Faybishenko, B.; Long, P. E.; Tokunaga, T. K.; Christensen, J. N.

    2015-12-01

    Net infiltration to the vadose zone, especially in arid or semi-arid climates, is an important control on microbial activity and solute and green house gas fluxes. To assess net infiltration, we performed a statistical analysis of meteorological data as the basis for hydrological and climatic investigations and predictions for the Rifle site, Colorado, USA, located within a floodplain in a mountainous region along the Colorado River, with a semi-arid climate. We carried out a statistical analysis of meteorological 30-year time series data (1985-2015), including: (1) precipitation data, taking into account the evaluation of the snowmelt, (2) evaluation of the evapotranspiration (reference and actual), (3) estimation of the multi-time-scalar Standardized Precipitation-Evapotranspiration Index (SPEI), (4) evaluation of the net infiltration rate, and (5) corroborative analysis of calculated net infiltration rate and groundwater recharge from radioisotopic measurements from samples collected in 2013. We determined that annual net infiltration percentage of precipitation varies from 4.7% to ~18%, with a mean of ~10%, and concluded that calculations of net infiltration based on long-term meteorological data are comparable with those from strontium isotopic investigations. The evaluation of the SPEI showed the intermittent pattern of droughts and wet periods over the past 30 years, with a detectable decreasein the duration of droughts with time. Local measurements within the floodplain indicate a recharge gradient with increased recharge closer to the Colorado River.

  4. Linking structural and functional connectivity in a simple runoff-runon model over soils with heterogeneous infiltrability

    NASA Astrophysics Data System (ADS)

    Harel, M.; Mouche, E.

    2012-12-01

    Runoff production on a hillslope during a rainfall event may be simplified as follows. Given a soil of constant infiltrability I, which is the maximum amount of water that the soil can infiltrate, and a constant rainfall intensity R, runoff is observed wherever R is greater than I. The infiltration rate equals the infiltrability where runoff is produced, R otherwise. When ponding time, topography, and overall spatial and temporal variations of physical parameters, such as R and I, are neglected, the runoff equation remains simple. In this study, we consider soils of spatially variable infiltrability. As runoff can re-infiltrate on down-slope areas of higher infiltrabilities (runon process), the resulting process is highly non-linear. The stationary runoff equation is: Qn+1 = max (Qn + (R - In)*Δx , 0) where Qn is the runoff arriving on pixel n of size Δx [L2/T], R and In the rainfall intensity and infiltrability on that same pixel [L/T]. The non-linearity is due to the dependence of infiltration on R and Qn, that is runon. This re-infiltration process generates patterns of runoff along the slope, patterns that organise and connect differently to each other depending on the rainfall intensity and the nature of the soil heterogeneity. In order to characterize the runoff patterns and their connectivity, we use the connectivity function defined by Allard (1993) in Geostatistics. Our aim is to assess, in a stochastic framework, the runoff organization on 1D and 2D slopes with random infiltrabilities (log-normal, exponential and bimodal distributions) by means of numerical simulations. Firstly, we show how runoff is produced and organized in patterns along a 2D slope according to the infiltrability distribution. We specifically illustrate and discuss the link between the statistical nature of the infiltrability and that of the flow-rate, with a special focus on the relations between the connectivities of both fields: the structural connectivity (infiltrability patterns

  5. The influence of a low air pressure environment on human metabolic rate during short-term (< 2 h) exposures.

    PubMed

    Cui, W; Wang, H; Wu, T; Ouyang, Q; Hu, S; Zhu, Y

    2017-03-01

    Passengers in aircraft cabins are exposed to low-pressure environments. One of the missing links in the research on thermal comfort under cabin conditions is the influence of low air pressure on the metabolic rate. In this research, we simulated the cabin pressure regime in a chamber in which the pressure level could be controlled. Three pressure levels (101/85/70 kPa) were tested to investigate how metabolic rate changed at different pressure levels. The results show that as pressure decreased, the respiratory flow rate (RFR) at standard condition (STPD: 0°C, 101 kPa) significantly decreased. Yet the oxygen (O2 ) consumption and carbon dioxide (CO2 ) production significantly increased, as reflected in the larger concentration difference between inhaled and exhaled air. A significant increase in the respiratory quotient (RQ) was also observed. For metabolic rate, no significant increase (P > 0.05) was detected when pressure decreased from 101 kPa to 85 kPa; however, the increase associated with a pressure decrease from 85 kPa to 70kPa was significant (P < 0.05). Empirical equations describing the above parameters are provided, which can be helpful for thermal comfort assessment in short-haul flights.

  6. Modeling contamination of shallow unconfined aquifers through infiltration beds

    USGS Publications Warehouse

    Ostendorf, D.W.

    1986-01-01

    We model the transport of a simply reactive contaminant through an infiltration bed and underlying shallow, one-dimensional, unconfined aquifer with a plane, steeply sloping bottom in the assumed absence of dispersion and downgradient dilution. The effluent discharge and ambient groundwater flow under the infiltration beds are presumed to form a vertically mixed plume marked by an appreciable radial velocity component in the near field flow region. The near field analysis routes effluent contamination as a single linear reservoir whose output forms a source plane for the one-dimensional, far field flow region downgradient of the facility; the location and width of the source plane reflect the relative strengths of ambient flow and effluent discharge. We model far field contaminant transport, using an existing method of characteristics solution with frame speeds modified by recharge, bottom slope, and linear adsorption, and concentrations reflecting first-order reaction kinetics. The near and far field models simulate transport of synthetic detergents, chloride, total nitrogen, and boron in a contaminant plume at the Otis Air Force Base sewage treatment plant in Barnstable County, Massachusetts, with reasonable accuracy.

  7. Modeling Contamination of Shallow Unconfined Aquifers Through Infiltration Beds

    NASA Astrophysics Data System (ADS)

    Ostendorf, D. W.

    1986-03-01

    We model the transport of a simply reactive contaminant through an infiltration bed and underlying shallow, one-dimensional, unconfined aquifer with a plane, steeply sloping bottom in the assumed absence of dispersion and downgradient dilution. The effluent discharge and ambient groundwater flow under the infiltration beds are presumed to form a vertically mixed plume marked by an appreciable radial velocity component in the near field flow region. The near field analysis routes effluent contamination as a single linear reservoir whose output forms a source plane for the one-dimensional, far field flow region downgradient of the facility; the location and width of the source plane reflect the relative strengths of ambient flow and effluent discharge. We model far field contaminant transport, using an existing method of characteristics solution with frame speeds modified by recharge, bottom slope, and linear adsorption, and concentrations reflecting first-order reaction kinetics. The near and far field models simulate transport of synthetic detergents, chloride, total nitrogen, and boron in a contaminant plume at the Otis Air Force Base sewage treatment plant in Barnstable County, Massachusetts, with reasonable accuracy.

  8. Difficulties in the evaluation and measuring of soil water infiltration

    NASA Astrophysics Data System (ADS)

    Pla-Sentís, Ildefonso

    2013-04-01

    Soil water infiltration is the most important hydrological parameter for the evaluation and diagnosis of the soil water balance and soil moisture regime. Those balances and regimes are the main regulating factors of the on site water supply to plants and other soil organisms and of other important processes like runoff, surface and mass erosion, drainage, etc, affecting sedimentation, flooding, soil and water pollution, water supply for different purposes (population, agriculture, industries, hydroelectricity), etc. Therefore the evaluation and measurement of water infiltration rates has become indispensable for the evaluation and modeling of the previously mentioned processes. Infiltration is one of the most difficult hydrological parameters to evaluate or measure accurately. Although the theoretical aspects of the process of soil water infiltration are well known since the middle of the past century, when several methods and models were already proposed for the evaluation of infiltration, still nowadays such evaluation is not frequently enough accurate for the purposes being used. This is partially due to deficiencies in the methodology being used for measuring infiltration, including some newly proposed methods and equipments, and in the use of non appropriate empirical models and approaches. In this contribution we present an analysis and discussion about the main difficulties found in the evaluation and measurement of soil water infiltration rates, and the more commonly committed errors, based on the past experiences of the author in the evaluation of soil water infiltration in many different soils and land conditions, and in their use for deducing soil water balances under variable and changing climates. It is concluded that there are not models or methods universally applicable to any soil and land condition, and that in many cases the results are significantly influenced by the way we use a particular method or instrument, and by the alterations in the soil

  9. Modeling the infiltration kinetics of molten aluminum into porous titanium carbide

    NASA Astrophysics Data System (ADS)

    Muscat, Daniel; Drew, Robin A. L.

    1994-11-01

    Capillary-induced melt infiltration is an attractive method of fabricating metal/ceramic composites, as it offers the advantage of producing material with a high ceramic content and near-net-shape fabrication, without the use of an external force. In this work, the kinetics of infiltration of molten Al in TiC preforms, having a pore size of approximately 1 µm and porosity ranging from 20 to 40 pct, were investigated. The rate of infiltration was continuously monitored using a Thermo-Gravimetric analyzer (TGA), which measured the weight change of the preform as the metal intruded the sample. Infiltration profiles where generated over a temperature range of 860 °C to 1085 °C. At lower temperatures, an incubation period was evident in the profiles. The average activation energy for the different preforms was 90 kJ/mol, indicating that some form of mass-transfer mechanism was involved in driving the process. Furthermore, sessile drop tests showed an unstable wetting angle over a long period of time. Such wetting kinetics were responsible for the incubation period during the infiltration. The infiltration rate was also seen to be slower as the preform density increased. This was due to the tortuous nature of the channels and was characterized using curves obtained for liquids infiltrating the same preforms at room temperature. Both the tortuosity and the unstable contact angle have to be considered when modeling the infiltration kinetics of such a system. The existing model was therefore modified by incorporating terms to describe the process more accurately. A good correlation with the experimental data was seen to exist.

  10. An Infiltration Exercise for Introductory Soil Science

    ERIC Educational Resources Information Center

    Barbarick, K. A.; Ippolito, J. A.; Butters, G.; Sorge, G. M.

    2005-01-01

    One of the largest challenges in teaching introductory soil science is explaining the dynamics of soil infiltration. To aid students in understanding the concept and to further engage them in active learning in the soils laboratory course, we developed an exercise using Decagon Mini-Disk Infiltrometers with a tension head (h[subscript o]) of 2 cm.…

  11. A review of reaction rates and thermodynamic and transport properties for an 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.; Lee, Kam-Pui

    1990-01-01

    Reaction rate coefficients and thermodynamic and transport properties are reviewed and supplemented for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium up to temperatures of 3000 K. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Curve fits are given for the various species properties for their efficient computation in flowfield codes. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in a high energy environment. Limitations of the approximate mixing laws are discussed for a mixture of ionized species. An electron number-density correction for the transport properties of the charged species is obtained. This correction has been generally ignored in the literature.

  12. Spatial variability of steady-state infiltration into a two-layer soil system on burned hillslopes

    USGS Publications Warehouse

    Kinner, D.A.; Moody, J.A.

    2010-01-01

    Rainfall-runoff simulations were conducted to estimate the characteristics of the steady-state infiltration rate into 1-m2 north- and south-facing hillslope plots burned by a wildfire in October 2003. Soil profiles in the plots consisted of a two-layer system composed of an ash on top of sandy mineral soil. Multiple rainfall rates (18.4-51.2 mm h-1) were used during 14 short-duration (30 min) and 2 long-duration simulations (2-4 h). Steady state was reached in 7-26 min. Observed spatially-averaged steady-state infiltration rates ranged from 18.2 to 23.8 mm h-1 for north-facing and from 17.9 to 36.0 mm h-1 for south-facing plots. Three different theoretical spatial distribution models of steady-state infiltration rate were fit to the measurements of rainfall rate and steady-state discharge to provided estimates of the spatial average (19.2-22.2 mm h-1) and the coefficient of variation (0.11-0.40) of infiltration rates, overland flow contributing area (74-90% of the plot area), and infiltration threshold (19.0-26 mm h-1). Tensiometer measurements indicated a downward moving pressure wave and suggest that infiltration-excess overland flow is the runoff process on these burned hillslope with a two-layer system. Moreover, the results indicate that the ash layer is wettable, may restrict water flow into the underlying layer, and increase the infiltration threshold; whereas, the underlying mineral soil, though coarser, limits the infiltration rate. These results of the spatial variability of steady-state infiltration can be used to develop physically-based rainfall-runoff models for burned areas with a two-layer soil system. ?? 2010 Elsevier B.V.

  13. Chronic Left Lower Lobe Pulmonary Infiltrates During Military Deployment.

    PubMed

    Hunninghake, John C; Skabelund, Andrew J; Morris, Michael J

    2016-08-01

    Deployment to Southwest Asia is associated with increased airborne hazards such as geologic dusts, burn pit smoke, vehicle exhaust, or air pollution. There are numerous ongoing studies to evaluate the potential effects of inhaled particulate matter on reported increases in acute and chronic respiratory symptoms. Providers need to be aware of potential causes of pulmonary disease such as acute eosinophilic pneumonia, asthma, and vocal cord dysfunction that have been associated with deployment. Other pulmonary disorders such as interstitial lung disease are infrequently reported. Not all deployment-related respiratory complaints may result from deployment airborne hazards and a broad differential should be considered. We present the case of a military member with a prolonged deployment found to have lobar infiltrates secondary to pulmonary vein stenosis from treatment for atrial fibrillation.

  14. Temperature sensitivity of photonic crystal fibers infiltrated with ethanol solutions

    NASA Astrophysics Data System (ADS)

    Chu Van, Lanh; Stefaniuk, Tomasz; Kasztelanic, Rafał; Cao Long, Van; Klimczak, Mariusz; Le Van, Hieu; Trippenbach, Marek; Buczyński, Ryszard

    2015-12-01

    In this paper we present a numerical study on the optimization of dispersion of a photonic crystal fiber infiltrated with water-ethanol mixtures. The advantage of such an approach stems from the fact that the dependence of the refractive index on temperature is larger in liquids than in solid materials. Here, we examine photonic crystal fibers with a regular, hexagonal lattice and with various geometrical and material parameters, such as different number of rings of holes, various lattice constants and the size of core and air-holes. Additionally, for the optimized structure with flat dispersion characteristics, we analyze the influence of temperature and concentration of the ethanol solution on the dispersion characteristic and the zero dispersion wavelength shift of the fundamental mode.

  15. A comparative study of terrestrial gamma dose rate in air measured by thermoluminescent dosimeter, portable survey meter and HPGe gamma spectrometer.

    PubMed

    Huang, Yan-Jun; Guo, Gui-Yin; He, Yi; Yang, Li-Tao; Shan, Zhen; Chen, Chao-Feng; Shang-Guan, Zhi-Hong

    2016-11-01

    In this paper, three different widely-used measurement techniques for environmental gamma dose rate were studied and compared, i.e., the thermoluminescent dosimeter, the portable survey meter and the spectrome