Science.gov

Sample records for air infiltration rate

  1. Air encapsulation during infiltration

    USGS Publications Warehouse

    Constantz, J.; Herkelrath, W.N.; Murphy, F.

    1988-01-01

    A series of field and laboratory experiments were performed to measure the effects of air encapsulation within the soil's transmission zone upon several infiltration properties. In the field, infiltration rates were measured using a double-cap infiltrometer and soil-water contents were measured using time-domain reflectometry (TDR). In the laboratory, infiltration experiments were peformed using repacked soil columns using TDR and CO 2 flooding. Results suggest that a significant portion of the total encapsulated air resided in interconnected pores within the soil's transmission zone. For the time scale considered, this residual air caused the effective hydraulic conductivity of the transmission zone to remain at a level no greater than 20% of the saturated hydraulic conductivity of the soil. -from Authors

  2. Method and apparatus for measuring the rate at which air infiltrates into and out of buildings

    SciTech Connect

    Dempsey, J. C.

    1985-01-15

    Tracer emission sources which emit tracer gas at a predetermined constant known rate are distributed throughout a building. The preferred source is a small vessel containing a vaporous perfluorocarbon tracer (PFT) substance having a very small bore hole in the top through which the PFT vapor can escape. Time is permitted for the tracer gas to mix uniformly throughout the building and for its concentration to equilibrate with infiltrating air. The concentration of the tracer is then measured and compared to the known volume of air in the building to determine the infiltration rate. In the preferred mode, the concentration is integrated and measured by continuously sampling the tracer gas at a constant rate on activated charcoal adsorbent over a period of several weeks. The amount of tracer substance accumulated on the adsorbent at the end of the test is directly related to the average tracer gas concentration which existed in the building during the sampling period and it can therefore be used to calculate an average infiltration rate during that period.

  3. 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.

  4. Wind-tunnel simulation of infiltration across permeable building envelopes: Energy and air pollution exchange rates

    SciTech Connect

    Meroney, R.N.; Neff, D.E.; Birdsall, J.B.

    1995-12-31

    This study investigates the fluid-modeling techniques used to simulate wind-forced natural ventilation rates of rectangular, single-cell low-rise buildings. A 1:25 scale model of the Texas Tech University Wind Engineering Research Field Laboratory is used in a boundary-layer wind tunnel to evaluate alternative strategies for simulating infiltration into permeable buildings. A new approach is proposed which should permit evaluation of a wide range of leakage situations. In addition data is used to critique standard full-scale tracer gas test methods.

  5. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Air infiltration. 3280.505 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration. (a) Envelope air infiltration. The opaque envelope shall be designed and constructed to limit...

  6. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Air infiltration. 3280.505 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration. (a) Envelope air infiltration. The opaque envelope shall be designed and constructed to limit...

  7. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Air infiltration. 3280.505 Section... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Thermal Protection § 3280.505 Air infiltration. (a) Envelope air infiltration. The opaque envelope shall be designed and constructed to limit...

  8. 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)

    Mizrahi, Guy; Weisbrod, Noam; Furman, Alex

    2015-04-01

    Entrapped air effects on infiltration under ponding conditions could be important for massive infiltration of managed aquifer recharge (MAR) or soil aquifer treatment (SAT) of treated wastewater. Earlier studies found that under ponding conditions, air is being entrapped and compressed until it reaches a pressure which will enable the air to escape (unstable air flow). They also found that entrapped 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, under ponding conditions, the effects of: (1) irregular surface topography on preferential air flow path development (stable air flow); (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 through 20 ports installed along the column perimeter. 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 surface (high and low surface zones). Additionally, Helle-show experiments were conducted in order to obtain a visual observation of preferential air flow path development. The measurements were carried out using a tension meter, air pressure transducers, TDR and video cameras. 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

  9. 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

  10. Infiltration rate measurement by active perfluorocarbon monitoring

    SciTech Connect

    Menzies, K.T.; Pong, C.M.; Randel, M.A. )

    1987-01-01

    The rate of air infiltration in homes and buildings is a significant factor affecting the magnitude of human exposure to air pollutants in the indoor environment. Several techniques have been utilized for the determination of air infiltration. These include building pressurization and tracer analysis, e.g., SF/sub 6/. Dietz and Cote at Brookhaven National Laboratory (BNL) have developed a simple, steady-state tracer kit that can be utilized by homeowners. This kit includes a source(s) of perfluorocarbon, i.e., perfluoromethylcyclohexane (PMCH) or perfluorodimethylcyclohexane (PDCH), and a passive sampling tube containing Ambersorb XE-347. Typically, the sampling tube is deployed for several days and then returned to a laboratory for analysis by thermal desorption/gas chromatography/electron capture detection. The authors developed an alternative sampling and analysis technique for PMCH/PDCH in homes. In order to facilitate monitoring of short-term infiltration rates (i.e., less than one day) they developed an active sorbent sampling method and solvent desorption/gas chromatography/electron capture detection analytical method. The method is based on the collection of PMCH on charcoal. The method validation, which is discussed in this article, includes analytical method development, selection of a solid sorbent, determination of desorption efficiency, analysis of breakthrough, testing of storage stability, and assessment of precision and accuracy in both the laboratory and field environment.

  11. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN 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...

  12. 24 CFR 3280.505 - Air infiltration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN 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...

  13. 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.

  14. Indoor air quality and infiltration in multifamily naval housing

    SciTech Connect

    Parker, G.B.; Wilfert, G.L.; Dennis, G.W.

    1984-11-01

    Measurements of indoor air quality and air infiltration were taken in three units of a multifamily housing complex at the Naval Submarine base in Bangor, Washington, over 5 consecutive days during the heating season of 1983. Three dwelling units of identical size constructed in 1978 were monitored, each in a separate two-story four-unit complex. One unit was a downstairs unit and the other two units were upstairs units. Two of the units were occupied by smokers (one downstairs and one upstairs). None of the units had combustion appliances. Pollutants monitored indoors included radon, formaldehyde, carbon monoxide, particulate matter, and nitrogen dioxide. Indoor and outdoor temperature and windspeed were also recorded. Outdoor formaldehyde and nitrogen dioxide were also measured. Air exchange was measured about three times during each 24-h period, using a perfluorocarbon tracer with automatic tracer sampling. The daily average air exchange rate ranged from 0.22 to 0.91 air changes per hour (ACH). Pollutant concentrations were generally low except for particulate matter in the units with smokers, which were two to four times higher than in the unit with nonsmokers. Levels of carbon monoxide were also slightly elevated in one of the units with a smoker compared to the unit with nonsmokers. 5 references, 4 figures, 4 tables.

  15. 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...

  16. 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

  17. Air infiltration and interzonal airflow measurements in research houses: Final report

    SciTech Connect

    Nagda, N.L.

    1988-08-01

    Four different but complementary methods--the tracer gas dilution method, single tracer constant concentration, passive perfluorocarbon tracers (constant release), and constant release of multiple halocarbon tracers with real-time analysis--were used to obtain detailed information on air infiltration and interzonal airflow rates in two bilevel research houses. The study included measurements of seasonal variations and differences between the houses, one of which was retrofitted in a previous EPRI study to reduce the air leakage area. Measurements showed that there had been little change in whole house infiltration rates during the 4 years since the retrofit. Differences between the houses with respect to whole house air infiltration rates were primarily the result of differences in downstairs air infiltration rates between the two houses. Zone-specific measurements indicated that downstairs infiltration rates were three to nine times higher than upstairs; infiltration rates were 30 to 60 percent lower in the downstairs of the retrofitted house than in the other house. The impact of the retrofit was also reflected by lower rates of airflow from the garage into the downstairs and from the upstairs to the attic. Airflows between the upstairs and downstairs of the houses exhibited seasonal variation due to stack effect action and operation of the central heating and cooling systems. Short-term interzonal airflow rates were as much as an order of magnitude higher than week-long average rates. Results of measurements with the different methods are also compared and discussed as they relate to advantages, limitations, and applicability of the methods in utility-sponsored measurement programs. 30 refs., 22 figs., 16 tabs.

  18. Brookhaven air infiltration measurement system (BNL/AIMS) description and application

    SciTech Connect

    Dietz, R.N.; Goodrich, R.W.; Cote, E.A.; Wieser, R.F.

    1983-08-01

    A unique capability to measure part-per-quadrillion concentrations of a family of perfluorocarbon tracers (PFTs) is presented. Together with our unique PFT source and passive sampler, measurement of average air exchange and infiltration rate can be determined for periods as short as 12 hours. A more expensive programmable sampler can provide information on a frequency of as little as once per minute for each of its 23 sampling tubes. The principal of AIMS is based on the applicable steady-state assumption that the average concentration (e.g., in pL/L) of a tracer vapor in a chamber (i.e., a building or room) is equal to the emission rate of the tracer source (e.g., in pL/min) divided by the air leakage or infiltration rate (e.g., in L/min). Knowing the source rate and measuring the average concentration then provides a means to calculate the air leakage rate. Extending this technique to a multichamber concept, in which a different type of PFT source is deployed in each chamber of a building, allows the calculation of not only the infiltration rates in each chamber but also the air exchange rates between chambers as well. Since both the PFT source and the passive sampler, a miniature Capillary Adsorption Tube Sampler (CATS), are about the size of a cigarette, inexpensive, and reusable, the BNL/AIMS is a very cost-effective means (if not the only means) for determining these air exchange rates.

  19. 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. PMID:24292460

  20. 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.

  1. 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...

  2. 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.

  3. Multizone infiltration monitoring system

    SciTech Connect

    Wortman, D.N.; Burch, J.; Judkoff, R.

    1982-06-01

    A multizone infiltration monitoring system (MIMS) using a single tracer gas has been developed. MIMS measures zonal infiltration and exfiltration as well as interzonal air movement rates. The system has been used at the 4-zone test house at the SERI interim field site, and this paper presents preliminary results. The present system can determine zonal infiltration rates, and the results show significant differences in infiltration rates for the various zones.

  4. 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...

  5. Comparison of the perfluorocarbon and tracer gas decay methods for assessing infiltration rates in residents

    SciTech Connect

    Schaap, L.; Leaderer, B.P.; Renes, S.; Verstraelen, H.; Tosun, T.; Dietz, R.N.

    1985-01-01

    The passive perfluorocarbon tracer (PFT) technique for determining air infiltration rates into homes and buildings was evaluated in an environmental chamber. The impact of sampler orientation at a constant ventilation rate and a constant temperature, of variable ventilation rate at a constant temperature, and of variable temperature at a constant ventilation rate were evaluated. The average relative standard deviation of 16 paired samplers deployed in experiment 1 was +- 1.9% +- 1.0% indicating good reproducibility of the passive sampling rate and sample analysis. No impact of sampler orientation with respect to low air velocities (<0.2 m/s) present in houses is expected. The passive samplers accurately measured the average tracer concentration as compared with calculations based on the known source strength (CO/sub 2/ decays) and the measured ventilation rate under conditions of a 3-fold variation in ventilation rates (experiment 2). Temperature cycling differences of 8/sup 0/C (experiment 3) did not produce a bias in the PFT determined ventilation rate. The PFT technique is applicable to the expected range of condition in homes and buildings. 3 refs., 1 fig., 1 tab.

  6. LAND USE AND MANAGEMENT IMPACT ON INFILTRATION RATE OF SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil physical properties and water infiltration were measured for five land use and soil management practices at North Appalachian Experimental Watersheds, Coshocton, Ohio. The five treatments were no-till with and without manure (NTM, NTWM), no-till corn-soybean rotation (NTCSR), conventional till...

  7. 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...

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

    NASA Astrophysics Data System (ADS)

    Martin, Deborah A.; Moody, John A.

    2001-10-01

    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 John Wiley & Sons, Ltd.

  9. 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.

  10. Evaluation of the perfluorocarbon tracer technique for determining infiltration rates in residences

    SciTech Connect

    Leaderer, B.P.; Schaap, L.; Dietz, R.N.

    1985-12-01

    A simple passive perfluorocarbon tracer (PFT) technique, for determining air infiltration rates into homes and buildings, was evaluated in a well-defined environmental chamber under experimental conditions of (1) constant temperature and ventilation rate, (2) constant temperature but variable ventilation rate, and (3) variable temperature but constant ventilation rate. Two PFT sources of known emission rate and temperature dependence produced chamber concentrations of 100-300 nL/m/sup 3/ (parts per trillion). The average relative standard deviation for sampling and analysis of 16 paired samplers in experiment 1 was +/- 1.9 +/- 1.0%, and there was negligible consequence of sampler orientation. For a 3-fold variation in ventilation rates (experiment 2), the passive samplers accurately measured the average chamber tracer concentration, but the PFT-determined ventilation rate had a 10% negative bias. Temperature cycling differences of as much as 8 /sup 0/C were accommodated to provide essentially no bias in the PFT-determined ventilation rate. The PFT technique is applicable to the expected range of conditions in homes and buildings.

  11. Time-Averaged Indoor Radon Concentrations and Infiltration RatesSampled in Four U.S. Cities

    SciTech Connect

    Doyle, S.M.; Nazaroff, W.W.; Nero, A.V.

    1983-09-01

    Indoor radon concentrations, measured in 58 houses over a four to five month period during the winter and spring of 1981-1982, varied from 0.1 to 16 pCi 1{sup -1} (4-590 Bq m{sup -3}). Average infiltration rates were determined for each house over the same period, based on a measurement of the effective leakage area and an infiltration model, and found to range from 0.2 to 2.2 air changes per hour (hr{sup -1}). Indoor radon concentrations correlated poorly with infiltration rates for houses within each city as well as for the entire sample. Differences in radon entry rates among houses thus appear to be more important than differences in infiltration rates in determining whether a house has high indoor radon levels, consistent with previous indications from grab-sample measurements. Radon entry rates and indoor radon concentrations were generally higher in houses in Fargo, ND and Colorado Springs, CO than in houses in Portland, ME and Charleston, NC.

  12. Explicit expressions for Green-Ampt (delta function diffusivity) infiltration rate and cumulative storage

    NASA Astrophysics Data System (ADS)

    Salvucci, Guido Daniel; Entekhabi, Dara

    1994-09-01

    The sharp wetting front model of infiltration (Green and Ampt, 1911; Philip, 1954) yields through simple integration an exact solution relating the infiltration rate (i), cumulative infiltration (I), and time (t). The relation, however, is implicit for i or I; i.e., it is of the form t = A[I - B ln (1 + I/B)]. Numerical iteration is required to find the infiltration rate, and furthermore, analytic manipulations are limited using this traditional formulation of the Green-Ampt infiltration. In this note we present an accurate expression for the infiltration rate in the form of a rapidly converging series in the variable τ = t/(t + χ). Truncating the series at four terms yields a useful expression for i(t). The proposed four-term expression gives less than 2% error at all times and is readily integrated to yield the cumulative infiltration I(t). In conjunction with the exact expression for time (t) given i or I, the proposed expression is useful in infiltration/runoff calculations that necessitate the time compression approximation (TCA).

  13. 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.

  14. 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.

  15. Experimental investigation of infiltration in soil with occurrence of preferential flow and air trapping

    NASA Astrophysics Data System (ADS)

    Snehota, Michal; Jelinkova, Vladimira; Sacha, Jan; Cislerova, Milena

    2015-04-01

    Recently, a number of infiltration experiments have not proved the validity of standard Richards' theory of the flow in soils with wide pore size distribution. Water flow in such soils under near-saturated conditions often exhibits preferential flow and temporal instability of the saturated hydraulic conductivity. An intact sample of coarse sandy loam from Cambisol series containing naturally developed vertically connected macropore was investigated during recurrent ponding infiltration (RPI) experiments conducted during period of 30 hours. RPI experiment consisted of two ponded infiltration runs, each followed by free gravitational draining of the sample. Three-dimensional neutron tomography (NT) image of the dry sample was acquired before the infiltration begun. The dynamics of the wetting front advancement was investigated by a sequence of neutron radiography (NR) images. Analysis of NR showed that water front moved preferentially through the macropore at the approximate speed of 2 mm/sec, which was significantly faster pace than the 0.3 mm/sec wetting advancement in the surrounding soil matrix. After the water started to flow out of the sample, changes in the local water content distribution were evaluated quantitatively by subtracting the NT image of the dry sample from subsequent tomography images. As a next stage, the experiment was repeated on a composed sample packed of ceramic and coarse sand. Series of infiltration runs was conducted in the sample with different initial water contents. The neutron tomography data quantitatively showed that both in natural soil sample containing the macropore and in the composed sample air was gradually transported from the region of fine soil matrix to the macropores or to the coarser material. The accumulation of the air bubbles in the large pores affected the hydraulic conductivity of the sample reducing it up to 50% of the initial value. This supports the hypothesis on strong influence of entrapped air amount and

  16. Capillary infiltration rates into porous media with applications to Silcomp processing

    SciTech Connect

    Einset, E.O.

    1996-02-01

    The rate of capillary rise of a liquid into a porous medium made up of consolidated particulates is analyzed. The infiltration distance is parabolic in time and can be modeled using the Washburn analysis. The effective pore radius is measured to be one to two orders of magnitude smaller than the particle size, particle spacing, and the median pore size as measured by mercury porosimetry. This result is interpreted using a modification of the Washburn model which models the porous medium as a single pore with varying diameter. Using a two-sized single pore model, the predicted infiltration rate is consistent with the measured values. In applying the two-sized single pore model to the reactive capillary infiltration of silicon into a carbonaceous preform in the Silcomp process, the effect of pore closure by the conversion of carbon to SiC is predicted. Using pore closure dimensions measured in a partial infiltration experiment, a decrease in the infiltration rate constant is predicted and is consistent with the measured infiltration rate.

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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...

  2. An empirical method for determining average soil infiltration rates and runoff, Powder River structural basin, Wyoming

    USGS Publications Warehouse

    Rankl, James G.

    1982-01-01

    This report describes a method to estimate infiltration rates of soils for use in estimating runoff from small basins. Average rainfall intensity is plotted against storm duration on log-log paper. All rainfall events are designated as having either runoff or nonrunoff. A power-decay-type curve is visually fitted to separate the two types of rainfall events. This separation curve is an incipient-ponding curve and its equation describes infiltration parameters for a soil. For basins with more than one soil complex, only the incipient-ponding curve for the soil complex with the lowest infiltration rate can be defined using the separation technique. Incipient-ponding curves for soils with infiltration rates greater than the lowest curve are defined by ranking the soils according to their relative permeabilities and optimizing the curve position. A comparison of results for six basins produced computed total runoff for all events used ranging from 16.6 percent less to 2.3 percent more than measured total runoff. (USGS)

  3. Field measurement of infiltration rate using an oscillating nozzle rainfall simulator in the cold semiarid grassland of Mongolia

    NASA Astrophysics Data System (ADS)

    Kato, Hiroaki; Onda, Yuichi; Tanaka, Yukiya; Asano, Maki

    2010-05-01

    In arid and semiarid rangelands, the process of desertification due to overgrazing has been described in terms of changes in surface vegetation cover and reduction in infiltration rate. Infiltration rate is one of the key indicators of overland flow generation and soil erosion; therefore, detecting reduction in infiltration rate is essential to assess land degradation of rangeland. Mongolia is located in northeastern Asia, and approximately 75 percent of its total land area consists of cold, semiarid grassland that is subjected to grazing throughout the year. Recent intensive grazing in Mongolia may be significantly reducing the infiltration rate of rangeland; however, very few data on the infiltration rate are currently available in this region. In this study, a new light-weight oscillating nozzle rainfall simulator was developed to generate the simulated rainfall with large raindrops and raindrop kinetic energy based on the design of existing rainfall simulators. We carried out a series of field infiltration tests for various surface cover conditions using the modified rainfall simulator and small plots (1 m2) in Mongolia. The objectives of this study were to elucidate the fundamental relationships between surface vegetation cover and infiltration rate in cold semiarid grassland. The results of field infiltration tests indicated that dense surface vegetation cover increased the infiltration rate significantly; however, a statistically significant correlation was found between the total surface cover (including rock fragment cover) and steady state infiltration rate, suggesting that surface cover by rock fragments also increased the infiltration rate to some extent. In general, steady state infiltration rate observed in the simulated rainfall experiment increases with increasing rainfall intensity until all parts of the plot are saturated (Murai and Iwasaki, 1975; Hawkins, 1982). The infiltration rates observed in simulated rainfall experiment is apparent

  4. 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

  5. Influence of the substitution of a grass cover by a mulch on infiltration rate

    NASA Astrophysics Data System (ADS)

    Sastre-Merlín, A.; Martínez-Pérez, S.; Bienes-Allas, R.; Molina-Navarro, E.; Martínez de Baroja, L.

    2012-04-01

    The study was carried out in an urban park of Madrid, in which it was decided to remove part of the prairie, replacing it by a mulch (pine bark). One year after this change in soil cover, infiltration tests were performed using the double ring infiltrometer (Müntz method). In each treatment the number of repetitions was 3. In the infiltration tests carried out the mulch not was withdraw, since we want to study their behavior before a rain or overhead irrigation. After one year, the infiltration rate showed ??much higher values in the prairie (18.9 mm h-1) than in the pine bark (8.4 mm h-1). Removing the prairie has meant a reduction in permeability of about 55%, which demonstrates the important role exerted by the radicular systems on infiltration. The origin is in the ability of roots to create preferred pathways circulation of the water. These pathways are of various types, and perhaps the most important are the root tubes, which are the channels that occur in the soil once the roots decompose. The finer roots create these pathways faster. These root tubes end up crumbling over time, so that is necessary to maintain the constant creation of new pipes in the soil. Under a prairie the number of root tubes that forms annually is enormous. By contrast, in absence of roots, in the surface horizon begins a process of gradual compaction, with reducing of the macroporosity and consequently impacting on the infiltration rate. The first consequence of this reduction in the infiltration rate is a poor flushing of salts from the soil of reclaimed water used in irrigation. This assertion has been corroborated by the analysis of the soil saturated paste, which shows an increasing of the electrical conductivities under the mulch. E.C. (μS cm-1) at the beginning of 2011 irrigation season (March) at different depths. Efficiency of the rains of autumn-winter by to wash soil salts. Depth (cm) PrairiePine bark 20 340 320 35 310 480 60 340 550 Therefore, the results indicate that

  6. Seasonal effects on multi-zone air infiltration in some typical US homes using a passive perfluorocarbon tracer technique

    SciTech Connect

    Dietz, R.N.; D'Ottavio, T.W.; Goodrich, R.W.

    1985-02-01

    The time-averaged air infiltration (I), exfiltration (E), and between-zone exchange rates in three, similarly sized, 2-story homes with basements were measured biweekly for one year with the passive PFT system. In February, total air changes per hour (ACH) were 0.20, 0.29, and 0.69 h/sup -1/, respectively, for houses D, B, and G, but total air flow in and out of the basements were in the ratio of about 1:4:7, respectively. House D had an average 1st floor ACH/sub I/ of 0.32 and ACH/sub E/ of 0.50 h/sup -1/ and, for the 2nd floor, 0.02 and 0.05 h/sup -1/, respectively; this house only needed slight weatherization on the 1st floor. Floor 1 in and out rates in B were 0.27 and 0.03 h/sup -1/, and for floor 2, 0.07 and 0.45 h/sup -1/, respectively, indicating a slight weatherization need. The house G 1st floor ACH/sub I/ and ACH/sub E/ were 0.72 and 0.35 h/sup -1/ and 2nd floor, 0.00 and 1.21 h/sup -1/, respectively, showing a need for significant weatherizing. Total seasonal ACH was correlated with temperature difference and wind speed within +-12% for all 3.

  7. Air kerma rate constants for radionuclides.

    PubMed

    Wasserman, H; Groenewald, W

    1988-01-01

    Conversion to SI units requires that the exposure rate constant which was usually quoted in R.h-1.mCi-1.cm2 be replaced by the air kerma rate constant with units m2.Gy.Bq-1.s-1. The conversion factor is derived and air kerma rate constants for 30 radionuclides used in nuclear medicine and brachytherapy are listed. A table for calculation of air kerma rates for other radionuclides is also given. To calculate absorbed dose to tissue, the air kerma rate has to be multiplied by approximately 1.1. A dose equivalent rate constant is thus listed which allows direct calculation of dose equivalent rate to soft tissue without resorting to exposure rate constants tabulated in the special units R.m2.mCi-1.h-1 which should no longer be used. PMID:3208786

  8. Air Controlman 1 & C: Rate Training Manual.

    ERIC Educational Resources Information Center

    Naval Training Command, Pensacola, FL.

    The manual is designed for use in preparing for advancement within the Navy Air Controlman rating, which designates a professional air traffic controller, unlike the more specialized center or tower controllers. However, minimum qualifications for the rating include completion of the Federal Aviation Administration (FAA) written examination for…

  9. 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.

  10. 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. PMID:24361727

  11. 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

  12. Effect of room air recirculation delay on the decay rate of tracer gas concentration

    SciTech Connect

    Kristoffersen, A.R.; Gadgil, A.J.; Lorenzetti, D.M.

    2004-05-01

    Tracer gas measurements are commonly used to estimate the fresh air exchange rate in a room or building. Published tracer decay methods account for fresh air supply, infiltration, and leaks in ductwork. However, the time delay associated with a ventilation system recirculating tracer back to the room also affects the decay rate. We present an analytical study of tracer gas decay in a well-mixed, mechanically-ventilated room with recirculation. The analysis shows that failing to account for delays can lead to under- or over-estimates of the fresh air supply, depending on whether the decay rate calculation includes the duct volume.

  13. Mechanical Behavior of Methane Infiltrated Coal: the Roles of Gas Desorption, Stress Level and Loading Rate

    NASA Astrophysics Data System (ADS)

    Wang, Shugang; Elsworth, Derek; Liu, Jishan

    2013-09-01

    We report laboratory experiments to investigate the role of gas desorption, stress level and loading rate on the mechanical behavior of methane infiltrated coal. Two suites of experiments are carried out. The first suite of experiments is conducted on coal (Lower Kittanning seam, West Virginia) at a confining stress of 2 MPa and methane pore pressures in the fracture of 1 MPa to examine the role of gas desorption. These include three undrained (hydraulically closed) experiments with different pore pressure distributions in the coal, namely, overpressured, normally pressured and underpressured, and one specimen under drained condition. Based on the experimental results, we find quantitative evidence that gas desorption weakens coal through two mechanisms: (1) reducing effective stress controlled by the ratio of gas desorption rate over the drainage rate, and (2) crushing coal due to the internal gas energy release controlled by gas composition, pressure and content. The second suite of experiments is conducted on coal (Upper B seam, Colorado) at confining stresses of 2 and 4 MPa, with pore pressures of 1 and 3 MPa, under underpressured and drained condition with three different loading rates to study the role of stress level and loading rate. We find that the Biot coefficient of coal specimens is <1. Reducing effective confining stress decreases the elastic modulus and strength of coal. This study has important implications for the stability of underground coal seams.

  14. Water quality impacts on infiltration rates and using chemical transport models as management tools

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of low quality waters for irrigation requires improved tools for managing soil salinity, and increased knowledge of chemical effects on infiltration, plant ion uptake, and impact to ground and surface water. Impacts of irrigation water with SAR (sodium adsorption ratio) 2,4,6,8 and l0 on infiltr...

  15. 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 ...

  16. An iminosugar-based heparanase inhibitor heparastatin (SF4) suppresses infiltration of neutrophils and monocytes into inflamed dorsal air pouches.

    PubMed

    Sue, Mayumi; Higashi, Nobuaki; Shida, Hiroaki; Kogane, Yusuke; Nishimura, Yoshio; Adachi, Hayamitsu; Kolaczkowska, Elzbieta; Kepka, Magdalena; Nakajima, Motowo; Irimura, Tatsuro

    2016-06-01

    Local infiltration of inflammatory cells is regulated by a number of biological steps during which the cells likely penetrate through subendothelial basement membranes that contain heparan sulfate proteoglycans. In the present study, we examined whether administration of heparastatin (SF4), an iminosugar-based inhibitor of heparanase, could suppress local inflammation and degradation of heparan sulfate proteoglycans in basement membranes. In a carrageenan- or formyl peptide-induced dorsal air pouch inflammation model, the number of infiltrated neutrophils and monocytes was significantly lower in mice after topical administration of heparastatin (SF4). The concentration of chemokines MIP-2 and KC in pouch exudates of drug-treated mice was similar to control. In a zymosan-induced peritonitis model, the number of infiltrated cells was not altered in drug-treated mice. To further test how heparastatin (SF4) influences transmigration of inflammatory neutrophils, its suppressive effect on migration and matrix degradation was examined in vitro. In the presence of heparastatin (SF4), the number of neutrophils that infiltrated across a Matrigel-coated polycarbonate membrane was significantly lower, while the number of neutrophils passing through an uncoated membrane was not altered. Lysate of bone marrow-derived neutrophils released sulfate-radiolabeled macromolecules from basement membrane-like extracellular matrix, which was suppressed by heparastatin (SF4). Heparan sulfate degradation activity was almost completely abolished after incubation of lysate with protein G-conjugated anti-heparanase monoclonal antibody, strongly suggesting that the activity was due to heparanase-mediated degradation. Taken together, in a dorsal air pouch inflammation model heparastatin (SF4) potentially suppresses extravasation of inflammatory cells by impairing the degradation of basement membrane heparan sulfate. PMID:27015605

  17. 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.

  18. 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

  19. 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

  20. 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...

  1. 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...

  2. 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

  3. Immunophenotypic features of tumor infiltrating lymphocytes from mammary carcinomas in female dogs associated with prognostic factors and survival rates

    PubMed Central

    2010-01-01

    Background The immune system plays an important role in the multifactorial biologic system during the development of neoplasias. However, the involvement of the inflammatory response in the promotion/control of malignant cells is still controversial, and the cell subsets and the mechanisms involved are poorly investigated. The goal of this study was to characterize the clinical-pathological status and the immunophenotyping profile of tumor infiltrating lymphocytes and their association with the animal survival rates in canine mammary carcinomas. Methods Fifty-one animals with mammary carcinomas, classified as carcinomas in mixed tumors-MC-BMT = 31 and carcinomas-MC = 20 were submitted to systematic clinical-pathological analysis (tumor size; presence of lymph node and pulmonary metastasis; clinical stage; histological grade; inflammatory distribution and intensity as well as the lymphocytic infiltrate intensity) and survival rates. Twenty-four animals (MC-BMT = 16 and MC = 8) were elected to the immunophenotypic study performed by flow cytometry. Results Data analysis demonstrated that clinical stage II-IV and histological grade was I more frequent in MC-BMT as compared to MC. Univariate analysis demonstrated that the intensity of inflammation (moderate/intense) and the proportion of CD4+ (≥ 66.7%) or CD8+ T-cells (<33.3%) were not associated with worse survival rate. Multivariate analysis demonstrated that only lymphocytic infiltrate intensity ≥ 600 (P = 0.02) remained as independent prognostic factor. Despite the clinical manifestation, the lymphocytes represented the predominant cell type in the tumor infiltrate. The percentage of T-cells was higher in animals with MC-BMT without metastasis, while the percentage of B-lymphocytes was greater in animals with metastasized MC-BMT (P < 0.05). The relative percentage of CD4+ T-cells was significantly greater in metastasized tumors (both MC-BMT and MC), (P < 0.05) while the proportion of CD8+ T-cells was higher in

  4. 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

  5. Effect of Saline Waste Solution Infiltration Rates on UraniumRetention and Spatial Distribution in Hanford Sediments

    SciTech Connect

    Wan, Jiamin; Tokunaga, Tetsu K.; Kim, Yongman; Wang, Zheming; Lanzirotti, Antonio; Saiz, Eduardo; Serne, R. Jeffrey

    2007-03-15

    The accidental overfilling of waste liquid from tank BX-102 at the Hanford Site in 1951 put about 10 metric tons of U(VI) into the vadose zone. In order to understand the dominant geochemical reactions and transport processes occurred during the initial infiltration and help understand current spatial distribution, we simulated the waste liquid spilling event in laboratory sediment columns using synthesized metal waste solution. We found that, as the plume propagating through sediments, pH decreased greatly (as much as 4 units) at the moving plume front. Infiltration flow rates strongly affect U behavior. Slower flow rates resulted in higher sediment-associated U concentrations, and higher flow rates ({ge} 5 cm/day) permitted practically unretarded U transport. Therefore, given the very high K{sub sat} of most of Hanford formation, the low permeability zones within the sediment could have been most important in retaining high concentrations of U during initial release into the vadose zone. Massive amount of colloids, including U-colloids, formed at the plume fronts. Total U concentrations (aqueous and colloid) within plume fronts exceeded the source concentration by up to 5-fold. Uranium colloid formation and accumulation at the neutralized plume front could be one mechanism responsible for highly heterogeneous U distribution observed in the contaminated Hanford vadose zone.

  6. 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...

  7. 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.

  8. 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.

  9. Current Problems and Issues in Air Freight Rates

    NASA Technical Reports Server (NTRS)

    Stout, A. R.

    1972-01-01

    Actions of the Civil Aeronautics Board in determining air freight rates are discussed. The tariff filings by domestic airlines for making basic changes in domestic fares and rates are reported. The roles of the carriers and the Civil Aeronautics Board in establishing freight rates are defined. Specific examples of areas of controversy in establishing freight rates are included. Methods for improving the air cargo and freight rate situation are proposed.

  10. 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...

  11. RESIDENTIAL AIR EXCHANGE RATES FOR USE IN INDOOR AIR AND EXPOSURE MODELING STUDIES

    EPA Science Inventory

    Data on air exchange rates are important inputs to indoor air quality models. ndoor air models, in turn, are incorporated into the structure of total human exposure models. ragmentary data on residential ventilation rates are available in various governmental reports, journal art...

  12. 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.

  13. 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.

  14. 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. PMID:26735865

  15. 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.

  16. Greenhouse Gas Growth Rates from AIRS Hyperspectral Radiance Time Series

    NASA Astrophysics Data System (ADS)

    Strow, L. L.; Desouza-Machado, S. G.; Hannon, S.; Imbiriba, B.; Schou, P.

    2009-12-01

    The AIRS seven year hyperspectral radiance record provides an ideal platform for measurings growth rates of infrared active minor gases, especially carbon dioxide and methane. The largest changes in CLARREO radiances will likely be due to increasing carbon dioxide and other greenhouse gases. We have produced a 5+ year record of almost cloud-free AIRS radiances, from which we have derived the radiance anomaly and linear time rate of change. The source of these radiances are the L1b radiances corrected for small frequency drifts. Growth rates of carbon dioxide, nitrous oxide, methane, ozone, and CFC11 are simultaneously derived from zonal averages of these radiance rates for tropics, and mid-latitude northern and southern hemispheres. The effective linear rate of change of ~5 layers of water vapor and temperature, plus the surface temperature are also simultaneously derived with the minor gas rates. No model data or prior is needed and more than 1000 channels are used in the fit. Sampling issues may preclude the use of the mid-latitude temperature and water vapor rates for climate analysis, but possibly not for the tropics. The resulting greenhouse gas growth rates agree very well with in-situ measurements, which suggests high radiometric stability for AIRS. Radiance intercomparisons for climate analysis between IASI and AIRS will also be presented.

  17. Relationship between air exchange rate and indoor VOC levels

    SciTech Connect

    Otson, R.; Williams, D.T.; Fellin, P.

    1998-12-31

    It is often assumed that the air quality is better in leaky than in airtight buildings. To test this anecdotal hypothesis, data from two Canadian surveys were examined. Indoor measurements of 28 volatile organic compounds (VOCs) were made by means of a passive sampling method during the 24 to 48 h study periods in both studies, and air exchange rates were determined by the perfluorocarbon tracer approach. The air exchange rates ranged between about 0.1 to 2.5 air changes per hour in 54 test homes in the Greater Toronto Area (GTA). Other information on building age and construction, renovation activities and occupant activities that potentially influenced indoor VOC concentrations in the homes was collected by means of a questionnaire. The statistical relationships between the concentrations of VOCs and air exchange were determined. Correlation coefficients between the airborne concentrations of each VOC and the air exchange rates for the homes were all < 0.1 indicating that the relationship between the air exchange and indoor VOC concentrations is tenuous. Since the questionnaire responses did not provide quantitative estimates of indoor emissions, a quantitative correlation between responses and indoor concentrations could not be established nor was a consistent pattern evident between these responses and the occurrence of high indoor concentrations. The lack of definitive quantitative relationships is not surprising considering the complexity of indoor environments, the lack of a detailed inventory of indoor sources and their emission rates and a lack of information or understanding of indoor sinks. The findings, on the effect of air exchange rates and the value of questionnaires in studies on indoor VOCs are consistent with findings in other similar studies.

  18. Debris flow probability and extent vary with infiltration rate and intensity-duration of rainfall: Mt. Mayon, Philippines

    NASA Astrophysics Data System (ADS)

    Maggio, J. C.; Rose, W. I.; Newhall, C. G.

    2010-12-01

    Volcanoclastic debris flows or lahars triggered by intense rainfall due to bulking are influenced by surface characteristics that reduce the downward infiltration of groundwater after saturation. Variations in surface cover control storm water runoff, thus affecting the timing and volume of water entering a river channel prone to lahars. Rainfall induced debris flows constitute a serious geologic hazard to communities in many parts of the world. The abundant loose erodible material on volcanoes increases the likelihood and severity of large debris flow events; this combined with dense populations make volcanoes an important area for lahar research and mitigation measures. This study was carried out on the slopes of the Republic of the Philippines most active volcano, Mt. Mayon, in hopes of increasing the understanding of debris flow initiation. Two tipping bucket rain gauges equipped with data loggers were deployed to determine an intensity-duration rainfall threshold during quiescent periods on Mayon. The steady-state infiltration capacities of Mayon’s substrates were determined using a double-ring infiltrometer ponding method. Additional infiltrometer experiments were carried out with an overlying simulated ash layer of 10, 20, 30, 40, 50, and 100 mm in order to quantify the effects of tephra cover on ground infiltration, adding supporting data that decreased infiltration and increased likelihood of debris flow initiation occur after an eruptive event. Finally, sieve analyses of the volcanic substrates were conducted to better understand the variations of infiltration and runoff due to grain size distribution. An intensity-duration rainfall threshold for quiescent periods on Mayon was estimated to be (I=46.2D-0.43). Average infiltration measurements ranged from 5.43-230.83 mm/hr depending on the type of substrate, vegetation cover, and grain size distribution. Simulated ash layers were found to increase initial infiltration (first 10 minutes) but decreased long

  19. Residential air exchange rates for use in indoor air and exposure modeling studies.

    PubMed

    Pandian, M D; Ott, W R; Behar, J V

    1993-01-01

    Data on air exchange rates are important inputs to indoor air quality models. Indoor air models, in turn, are incorporated into the structure of total human exposure models. Fragmentary data on residential ventilation rates are available in various governmental reports, journal articles, and contractor reports. Most of the published papers present data on only a few homes to answer very specialized questions, and none of these publications summarize the ventilation rates of a large population of homes across the United States. Brookhaven National Laboratory (BNL) has conducted more than 4000 residential perfluorocarbon tracer (PFT) measurements and brought them together into a large data base from about 100 studies in the United States and elsewhere. This paper analyzes the BNL PFT data base to generate frequency distributions and summary statistics for different regions of the United States, different seasons, and different levels within the homes. The data analyses suggest that residential ventilation rates are similar in the northeastern and northwestern states but higher in the southwestern states. Winter and fall ventilation rates are similar, but the rates are slightly higher in spring, and much higher in summer. Multi-level residences have higher air exchange rates than single-level residences. Although the BNL data are not a representative sample of homes in the United States, these analyses give insight into the range of air exchange rates found in the United States under a great variety of conditions and are intended for use by developers of models of indoor air quality and total human exposure. PMID:8173341

  20. 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.

  1. 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

  2. Ventilating-air change rate versus particulate contaminant spread

    SciTech Connect

    Langer, G.; Deitesfeld, C.A.

    1987-11-13

    This study provides information on the spread of particulate contamination from glovebox leaks in plutonium manufacturing facilities, with emphasis on the effect of ventilating-air change rate on contaminated spread. A new, very sensitive aerosol tracer technique was developed to simulate plutonium aerosol leaks and its dispersion in a room. The tracer, a submicron aerosol of phloroglucinol, does not interfere with work activity and is detected by its ability to form ice crystals in a supercooled cloud. This technique was applied in Buildings 371 and 707 plutonium production areas. The tracer spread throughout the rooms in a few minutes and reached its equilibrium concentration in 10 to 25 min. Also, to clear the room of all tracer took about the same time. In one room, tracer concentration decreased proportionally to the air change rate, while in the second one, air change rate had no effect. This points out the need for air velocity data. Also, future work must include simultaneous particle concentration measurements at several points. 4 refs., 9 figs., 2 tabs.

  3. 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.

  4. 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.

  5. 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.

  6. 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. PMID:23715084

  7. Infiltrative Cardiomyopathies

    PubMed Central

    Bejar, David; Colombo, Paolo C; Latif, Farhana; Yuzefpolskaya, Melana

    2015-01-01

    Infiltrative cardiomyopathies can result from a wide spectrum of both inherited and acquired conditions with varying systemic manifestations. They portend an adverse prognosis, with only a few exceptions (ie, glycogen storage disease), where early diagnosis can result in potentially curative treatment. The extent of cardiac abnormalities varies based on the degree of infiltration and results in increased ventricular wall thickness, chamber dilatation, and disruption of the conduction system. These changes often lead to the development of heart failure, atrioventricular (AV) block, and ventricular arrhythmia. Because these diseases are relatively rare, a high degree of clinical suspicion is important for diagnosis. Electrocardiography and echocardiography are helpful, but advanced techniques including cardiac magnetic resonance (CMR) and nuclear imaging are increasingly preferred. Treatment is dependent on the etiology and extent of the disease and involves medications, device therapy, and, in some cases, organ transplantation. Cardiac amyloid is the archetype of the infiltrative cardiomyopathies and is discussed in great detail in this review. PMID:26244036

  8. The Effects of Air Pollution on Ischemic Stroke Admission Rate

    PubMed Central

    Alimohammadi, Hossein; Fakhri, Sara; Derakhshanfar, Hojjat; Hosseini-Zijoud, Seyed-Mostafa; Safari, Saeed

    2016-01-01

    The present study aimed to determine the relationship between the level of air pollutants and the rate of ischemic stroke (IS) admissions to hospitals. In this retrospective cross-sectional study, stroke admissions (January-March 2012 and 2013) to an emergency department and air pollution and meteorological data were gathered. The relationship between air pollutant levels and hospital admission rates were evaluated using the generalize additive model. In all 379 patients with IS were referred to the hospital (52.5% male; mean age 68.2±13.3 years). Both transient (p<0.001) and long-term (p<0.001) rises in CO level increases the risk of IS. Increased weekly (p<0.001) and monthly (p<0.001) average O3 levels amplifies this risk, while a transient increase in NO2 (p<0.001) and SO2 (p<0.001) levels has the same effect. Long-term changes in PM10 (p<0.001) and PM2.5 (p<0.001) also increase the risk of IS. The findings showed that the level of air pollutants directly correlates with the number of stroke admissions to the emergency department. PMID:26866000

  9. The Effects of Air Pollution on Ischemic Stroke Admission Rate.

    PubMed

    Alimohammadi, Hossein; Fakhri, Sara; Derakhshanfar, Hojjat; Hosseini-Zijoud, Seyed-Mostafa; Safari, Saeed; Hatamabadi, Hamid Reza

    2016-01-01

    The present study aimed to determine the relationship between the level of air pollutants and the rate of ischemic stroke (IS) admissions to hospitals. In this retrospective cross-sectional study, stroke admissions (January-March 2012 and 2013) to an emergency department and air pollution and meteorological data were gathered. The relationship between air pollutant levels and hospital admission rates were evaluated using the generalize additive model. In all 379 patients with IS were referred to the hospital (52.5% male; mean age 68.2±13.3 years). Both transient (p<0.001) and long-term (p<0.001) rises in CO level increases the risk of IS. Increased weekly (p<0.001) and monthly (p<0.001) average O3 levels amplifies this risk, while a transient increase in NO2 (p<0.001) and SO2 (p<0.001) levels has the same effect. Long-term changes in PM10 (p<0.001) and PM2.5 (p<0.001) also increase the risk of IS. The findings showed that the level of air pollutants directly correlates with the number of stroke admissions to the emergency department. PMID:26866000

  10. 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…

  11. 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...

  12. 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.

  13. 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

    2014-11-01

    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 and

  14. 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

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

    PubMed

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

    2003-01-01

    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 Topopah 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 (ESF), 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

  16. 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

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

    NASA Astrophysics Data System (ADS)

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

    2003-05-01

    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 Topopah 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 (ESF), 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

  18. The air-kerma rate constant of 192Ir.

    PubMed

    Ninković, M M; Raiĉevìć, J J

    1993-01-01

    The air-kerma rate constant gamma delta (and its precursors), as one of the basic radiation characteristics of 192Ir, was determined by many authors. Analysis of accessible data on this quantity led us to the conclusion that published data strongly disagree. That is the reason we calculated this quantity on the basis of our and many other authors' gamma-ray spectral data and the latest data for mass energy-transfer coefficients for air. In this way, a value was obtained for gamma delta of 30.0 +/- 0.9 a Gy m2 s-1 Bq-1 for an unshielded 192Ir source and 27.8 +/- 0.9 a Gy m2s -1Bq-1 for a standard packaged radioactive source taking into account attenuation of gamma rays in the platinum source wall. PMID:8416220

  19. Multizone infiltration measurements in homes and buildings using a passive perfluorocarbon tracer method

    SciTech Connect

    Dietz, R.N.; D'Offavio, T.W.; Goodrich, R.W.

    1985-01-01

    A miniature passive perfluorocarbon tracer system was successfully applied to the determination of air infiltration and exfiltration rates from each zone of a multizoned structure, as well as the air exchange rates between zones in homes, multiple unit condominiums, naturally ventilated apartment buildings, and large commercial buildings with multiple air-handling systems. Use of the multizone technique in indoor quality assessments and air-handling system stratification studies appears to be quite feasible with the availability of this measuring system.

  20. Expected rates with mini-arrays for air showers

    NASA Technical Reports Server (NTRS)

    Hazen, W. E.

    1985-01-01

    As a guide in the design of mini-arrays used to exploit the Linsley effect in the study of air showers, it is useful to calculate the expected rates. The results can aid in the choice of detectors and their placement or in predicting the utility of existing detector systems. Furthermore, the potential of the method can be appraised for the study of large showers. Specifically, we treat the case of a mini-array of dimensions small enough compared to the distance of axes of showers of interest so that it can be considered a point detector. The input information is taken from the many previous studies of air showers by other groups. The calculations will give: (1) the expected integral rate, F(sigma, rho), for disk thickness, sigma, or rise time, t sub 1/2, with local particle density, rho, as a parameter; (2) the effective detection area A(N) with sigma (min) and rho (min) and rho (min) as parameters; (3) the expected rate of collection of data F sub L (N) versus shower size, N.

  1. 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.

  2. 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

  3. Local Anaesthetic Infiltration and Indwelling Postoperative Wound Catheters for Patients with Hip Fracture Reduce Death Rates and Length of Stay

    PubMed Central

    Harrison, William D.; Lees, Deborah; A'Court, Jamie; Ankers, Thomas; Harper, Ian; Inman, Dominic; Reed, Mike R.

    2015-01-01

    Background. An analgesic enhanced recovery (ER) protocol for patients with a hip fracture was introduced. It was hypothesised that the ER would reduce pain, length of stay and improve clinical outcomes. The protocol used intraoperative infiltration of levobupivacaine followed by ongoing wound infusions. Methods. Consecutive patients admitted to two hospitals were eligible for the ER protocol. Numerical Reporting Scale pain scores (0–10) were recorded alongside opiate requirements. 434 patients in the ER group (316 full ER, 90 partial ER, and 28 no ER) were compared to a control group (CG) of 100 consecutive patients managed with traditional opiate analgesia. Results. Mean opiate requirement was 49.2 mg (CG) versus 32.5 mg (ER). Pain scores were significantly reduced in the full ER group, p < 0.0001. Direct discharge home and mean acute inpatient stay were significantly reduced (p = 0.0031 and p < 0.0001, resp.). 30-day mortality was 15% (CG) versus 5.5% (ER), p = 0.0024. Conclusions. This analgesic ER protocol for patients with a hip fracture was safe and effective and was associated with reduced inpatient stay and mortality. PMID:26649330

  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. 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. PMID:27108365

  6. Effects of Hyperbaric Oxygen at 1.25 Atmospheres Absolute with Normal Air on Macrophage Number and Infiltration during Rat Skeletal Muscle Regeneration

    PubMed Central

    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. PMID:25531909

  7. 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.

  8. 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.

  9. 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.

  10. Analysis of Infiltration Uncertainty

    SciTech Connect

    R. McCurley

    2003-10-27

    The primary objectives of this uncertainty analysis are: (1) to develop and justify a set of uncertain parameters along with associated distributions; and (2) to use the developed uncertain parameter distributions and the results from selected analog site calculations done in ''Simulation of Net Infiltration for Modern and Potential Future Climates'' (USGS 2001 [160355]) to obtain the net infiltration weighting factors for the glacial transition climate. These weighting factors are applied to unsaturated zone (UZ) flow fields in Total System Performance Assessment (TSPA), as outlined in the ''Total System Performance Assessment-License Application Methods and Approach'' (BSC 2002 [160146], Section 3.1) as a method for the treatment of uncertainty. This report is a scientific analysis because no new and mathematical physical models are developed herein, and it is based on the use of the models developed in or for ''Simulation of Net Infiltration for Modern and Potential Future Climates'' (USGS 2001 [160355]). Any use of the term model refers to those developed in the infiltration numerical model report. TSPA License Application (LA) has included three distinct climate regimes in the comprehensive repository performance analysis for Yucca Mountain: present-day, monsoon, and glacial transition. Each climate regime was characterized using three infiltration-rate maps, including a lower- and upper-bound and a mean value (equal to the average of the two boundary values). For each of these maps, which were obtained based on analog site climate data, a spatially averaged value was also calculated by the USGS. For a more detailed discussion of these infiltration-rate maps, see ''Simulation of Net Infiltration for Modern and Potential Future Climates'' (USGS 2001 [160355]). For this Scientific Analysis Report, spatially averaged values were calculated for the lower-bound, mean, and upper-bound climate analogs only for the glacial transition climate regime, within the

  11. 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...

  12. 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...

  13. 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

  14. A comparative analysis of infiltration rates below a pasture and a secondary forest on Santa Cruz Island, Galapagos

    NASA Astrophysics Data System (ADS)

    d'Ozouville, N.; Pryet, A.; Tournebize, J.; Chaumont, C.; Gonzáles, A.; Dominguez, C.; Fuente-Tomai, P.; Fernandez, J.; Violette, S.

    2011-12-01

    The potential effects of land use changes on groundwater recharge are being investigated on the windward side of Santa Cruz Island, Galapagos. Comparative studies allow the identification of the processes (evaporation, transpiration, soil water storage) at the vegetation/soil interface leading to contrasting recharge rates under different land covers. During one year, we monitored soil water dynamics under two adjacent study plots differing only by their vegetation cover: a pasture and a secondary forest. Climatic variables were monitored above the pasture and completed by throughfall monitoring under the forest. Tensiometers provide a direct measurement of the driving force of water dynamics in the soil: the hydraulic head gradient. In the two plots, tensiometers were set up in vertical profiles together with soil water content probes and connected to an automatic acquisition device. The forest stand has a higher canopy storage capacity and aerodynamic resistance, which causes evaporation losses to be higher. This is confirmed by throughfall measurements: only ca. 80% of gross precipitation reaches the ground. Expectedly, soil water tension profiles present clearly different behaviors in the pasture and in the forest. Despite high uncertainties on estimated recharge rates, we show that parallel monitoring of soil hydrodynamics in these two study plots provides valuable insights and may help to manage or anticipate the potential effect of deforestation or invasion by introduced plants on the hydrology of Santa Cruz Island, Galapagos.

  15. Effect of hydraulic loading rate on pollutant removal efficiency in subsurface infiltration system under intermittent operation and micro-power aeration.

    PubMed

    Yang, Yongqiang; Zhan, Xuan; Wu, Shijun; Kang, Mingliang; Guo, Jianan; Chen, Fanrong

    2016-04-01

    The low hydraulic loading rate (HLR) greatly restricts the wide application of subsurface wastewater infiltration system (SWIS) in densely populated areas. To increase the HLR, an innovative SWIS was developed using cyclic operation mode. In each cycle, a wastewater feeding period is followed by a drying period, in which the aeration is conducted by a medium-pressure fan. Results indicated that the removal rate of TOC and NH4(+)-N were more than 85% at HLR of 0.5m(3)/m(2)d, whereas the TN removal rate was lower than 20%, indicating that the aeration was efficient and denitrification process was largely limited in the SWIS. When HLR decreased from 0.5 to 0.2m(3)/m(2)d, the pollutant removal efficiency enhanced slightly except for TN. Overall, the intermittent operation and micro-power aeration, combined with shunting the pollutant loading were really helpful for SWIS to achieve higher HLR, which offers a reference for the design of innovative SWIS. PMID:26826957

  16. 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

  17. 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

  18. Estimation of uncertainty in tracer gas measurement of air change rates.

    PubMed

    Iizuka, Atsushi; Okuizumi, Yumiko; Yanagisawa, Yukio

    2010-12-01

    Simple and economical measurement of air change rates can be achieved with a passive-type tracer gas doser and sampler. However, this is made more complex by the fact many buildings are not a single fully mixed zone. This means many measurements are required to obtain information on ventilation conditions. In this study, we evaluated the uncertainty of tracer gas measurement of air change rate in n completely mixed zones. A single measurement with one tracer gas could be used to simply estimate the air change rate when n = 2. Accurate air change rates could not be obtained for n ≥ 2 due to a lack of information. However, the proposed method can be used to estimate an air change rate with an accuracy of <33%. Using this method, overestimation of air change rate can be avoided. The proposed estimation method will be useful in practical ventilation measurements. PMID:21318005

  19. HAZARDOUS AIR POLLUTANTS: WET REMOVAL RATES AND MECHANISMS

    EPA Science Inventory

    Fourteen hazardous organic air pollutants were evaluated for their potentials to be wet deposited by precipitation scavenging. This effort included a survey of solubilities (Henry's Law constants) in the literature, measurement of solubilities of three selected species, developme...

  20. REFINED PHOTOLYSIS RATES FOR ADVANCED AIR QUALITY MODELING SYSTEM

    EPA Science Inventory

    Accurate modeling of photochemistry is critical and fundamental to reducing the uncertainty in air quality model predictions. lmost all chemical reactions in the atmosphere are initiated by the photodissociation of a number of trace gases. irect measure of this photodissociation ...

  1. Modeled and measured infiltration: Phase II. A detailed case study of three homes; Final report

    SciTech Connect

    Palmiter, L.; Bond, T.

    1994-01-01

    The primary purpose of this work was to investigate the impacts of wind, temperature and mechanical systems on infiltration in real homes, with a view toward resolving infiltration modeling problems raised in recent studies. This report contains results from the second phase of an ongoing project. In Phase I, detailed infiltration and pressure measurements were made by Lawrence Berkeley Laboratory on four homes in the Pacific Northwest. In this phase, similar measurements were made on an additional three homes, chosen for maximal wind exposure. For the reader`s convenience the summary tables in this report contain data from all seven homes in a uniform format. The predictions of two natural infiltration models (LBL and AIM-2) were compared in detail with one another and the measured data. An improved method of calculating the height parameter for both models is proposed. A modification of the LBL wind model is also proposed. A simple model is presented to incorporate the infiltration effects of exhaust and supply ventilation systems and unbalanced flows due to duct leakage. An unbalanced flow to the conditioned space induces approximately one-half of its magnitude in additional infiltration when it is small relative to natural infiltration. Forced-air distribution systems were investigated in detail. Air handlers and associated duct leakage can have large effects on living-zone infiltration rates; for these homes the median increase in overall infiltration was 21%, based on a runtime of six hours per day. Closing even a single bedroom door can cause a major increase in infiltration when the air handler runs. The bias due to use of a time-averaged concentration tracer technique (i.e., the perfluorocarbon (PFT) method) was assessed and found to be small for the living zones, and large for the wind-dominated, ventilated crawl space and attic zones.

  2. Multizone infiltration measurements in homes and buildings determined with a passive perfluorocarbon tracer method

    SciTech Connect

    Dietz, R.N.; D'Ottavio, T.W.; Goodrich, R.W.

    1985-03-01

    A miniature passive perfluorocarbon tracer system was successfully applied to the determination of air infiltration and exfiltration rates from each zone of a multizoned structure as well as the air exchange rates between zones in homes, multiple unit condominiums, naturally ventilated apartment buildings, and large commercial buildings with multiple air handling systems. Use of the multizone technique in indoor air quality assessments and air handling system stratification studies appears to be quite feasible with the availability of this measurement system. 16 refs., 8 figs., 6 tabs.

  3. 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 ...

  4. 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.

  5. VOLATILIZATION RATES FROM WATER TO INDOOR AIR PHASE II

    EPA Science Inventory

    Contaminated water can lead to volatilization of chemicals to residential indoor air. Previous research has focused on only one source (shower stalls) and has been limited to chemicals in which gas-phase resistance to mass transfer is of marginal significance. As a result, attemp...

  6. Inverse modelling of multiple infiltration-outflow experiments

    NASA Astrophysics Data System (ADS)

    Sobotková, M.; Snehota, M.; Dohnal, M.; Cislerova, M.

    2009-04-01

    Changes of (quasi)steady state water flow rates were observed in laboratory infiltration experiments done on columns of compacted sand and on two undisturbed soil columns of sandy loam and loamy sand cambisol soil. Infiltration-outflow experiments consisted of series of ponded infiltration runs with seepage face boundary condition at the lower end of columns. The initial water contents were different for each run. The results of the experiment done on an undisturbed soil column showed that the flux rates and water contents measured during quasi-steady state differ between infiltration runs. This finding contradicts the standard theory. The fluctuations of the water content during the steady state flow can be ascribed to the variations in volume of the entrapped air. The same behaviour was not observed in the sample of homogeneous sand. Computer tomography was used to characterize the structure of the undisturbed soil sample with focus on potential preferential flow pathways. In order to asses the changes between runs quantitatively, hydraulic characteristics were estimated for each infiltration run separately by inverse modelling. Experimental outflow data and tensiometric pressure head data were used as an input for inverse modelling. Numerical code based on dual permeability approach was coupled with parameter estimator. Result of the inverse modelling for each column is specific set of hydraulic properties for each infiltration run of particular soil column. Since we hypothesise that the steady state flow is affected by soil water content at the beginning of the infiltration run, we will study the relationships between initial moistures and hydraulic parameters values. Furthermore we will test if the above phenomena can be ascribed to hysteresis of hydraulic functions.

  7. Rating procedure for mixed-air-source unitary air conditioners and heat pumps operating in the cooling mode

    SciTech Connect

    Domanski, P.A.

    1986-02-01

    A procedure is presented for rating split, residential air conditioners and heat pumps operating in the cooling mode that are made up of an evaporator unit combined with a condensing unit that has been rated under current procedures in conjunction with a different evaporator unit. The procedure allows calculation of capacity at the 95/sup 0/ F rating point and seasonal energy efficiency ratio, SEER, without performing laboratory tests of the complete system.

  8. Exploring Variation and Predictors of Residential Fine Particulate Matter Infiltration

    PubMed Central

    Clark, Nina A.; Allen, Ryan W.; Hystad, Perry; Wallace, Lance; Dell, Sharon D.; Foty, Richard; Dabek-Zlotorzynska, Ewa; Evans, Greg; Wheeler, Amanda J.

    2010-01-01

    Although individuals spend the majority of their time indoors, most epidemiological studies estimate personal air pollution exposures based on outdoor levels. This almost certainly results in exposure misclassification as pollutant infiltration varies between homes. However, it is often not possible to collect detailed measures of infiltration for individual homes in large-scale epidemiological studies and thus there is currently a need to develop models that can be used to predict these values. To address this need, we examined infiltration of fine particulate matter (PM2.5) and identified determinants of infiltration for 46 residential homes in Toronto, Canada. Infiltration was estimated using the indoor/outdoor sulphur ratio and information on hypothesized predictors of infiltration were collected using questionnaires and publicly available databases. Multiple linear regression was used to develop the models. Mean infiltration was 0.52 ± 0.21 with no significant difference across heating and non-heating seasons. Predictors of infiltration were air exchange, presence of central air conditioning, and forced air heating. These variables accounted for 38% of the variability in infiltration. Without air exchange, the model accounted for 26% of the variability. Effective modelling of infiltration in individual homes remains difficult, although key variables such as use of central air conditioning show potential as an easily attainable indicator of infiltration. PMID:20948956

  9. Correlation between indoor radon concentration and dose rate in air from terrestrial gamma radiation in Japan.

    PubMed

    Fujimoto, K

    1998-09-01

    A correlation between the indoor radon concentration and dose rate in air from terrestrial gamma radiation is studied using the results of nationwide indoor radon and external exposure surveys, although the surveys were not conducted at the same time nor at the same location. The radon concentration shows a log-normal-like distribution, whereas the terrestrial gamma radiation dose rate in air shows a normal-like distribution. A log-linear scatterplot for each pair of the indoor radon concentration and gamma-ray dose rate in air in each city reveals a clear relationship. The average, maximum, and minimum as well as regression line of radon concentration were found to increase with the gamma-ray dose rate in air. The group in higher quantile of radon concentration shows larger dependence on the gamma-ray dose rate. The rate of increase of radon concentration with the gamma-ray dose rate in air depends on the house structure. The wooden house has a larger rate of increase than the concrete house, and the regression lines cross at high air dose rate. Based on the finding in the present study a certain criterion level of air dose rate could be established and used for an effective survey to find out which houses might require a remedial action in conjunction with other screening tools. The criterion level of air dose rate might be more effective if the level is set for each house structure since the rate of increase of radon concentration depends on house structure. PMID:9721838

  10. Fractal structure of the distributions of air dose rates in Koriyama city in Fukushima.

    PubMed

    Ishihara, Masamichi

    2014-10-01

    The authors investigated the fractal structure of the distributions of air dose rates in Koriyama city in Fukushima using data published by the Fukushima Prefectural and Koriyama City governments. Relative frequency data of air dose rates (strength distribution) could be well fitted with a q-distribution. In the present analysis, the relative frequency decreases approximately as s for high air dose rate values, where the quantity s represents air dose rate. The fractal dimension is a function of the threshold sth of air dose rate. The fractal dimension is approximately 1.59 when sth is the average of the air dose rates in Koriyama (0.9 μSv h) and decreases with increasing the threshold: it is approximately 1.97 for sth = 0.6 μSv h and 1.40 for sth = 1.2 μSv h. These results confirm that the strength distribution behaves like a power function for high air dose rate values and that the fallout pattern can be described as a fractal. PMID:25162424

  11. 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). PMID:25944962

  12. Soil properties controlling infiltration in volcanic soils

    NASA Astrophysics Data System (ADS)

    Neris, Jonay; Tejedor, Marisa; Jiménez, Concepción

    2013-04-01

    Soil water infiltration is an important process whose behaviour depends on external factors and soil properties that vary depending on the type of soil. The soil parameters affecting the infiltration capacity of six soil orders all formed on volcanic materials (andisols, vertisols, alfisols, aridisols, inceptisols, and entisols) and contribute to the differences between them were studied in this paper. A total of 108 sites were selected on the island of Tenerife (Spain). The main soil properties were analysed and the steady-state infiltration rate measured using a double-ring infiltrometer. The relationship between the soil properties and infiltration was modelled using statistical Principal Components Analysis and regressions. The research concludes that the relation between structural development and texture play a decisive role. The high structural development of non-vitric andisols, due to the high organic matter and short-range-order mineral content, leads to an extremely fast infiltration rate. The structural instability and fine texture of aridisols produce low infiltration. In less developed soils (entisols and vitric andisols) where aggregate formation is minimal or non-existent, the coarse grain size is the relevant factor determining their very fast and extremely fast infiltration. In vertisols and alfisols, which have strong aggregation but low stability, clay type and content play an important role and lead to a moderate and moderately fast steady-state infiltration rate, respectively. In the most typic inceptisols, with moderate structural development and stability, the balance of the properties is largely responsible for the intermediate infiltration rate observed.

  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. 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.

  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. PMID:25187115

  16. 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...

  17. Daily changes in oxygen saturation and pulse rate associated with particulate air pollution and barometric pressure.

    PubMed

    Dockery, D W; Pope, C A; Kanner, R E; Martin Villegas, G; Schwartz, J

    1999-01-01

    Epidemiologic studies have linked fine particulate air pollution with increases in morbidity and mortality rates from cardiopulmonary complications. Although the underlying biologic mechanisms responsible for this increase remain largely unknown, potential pathways include transient declines in blood oxygenation and changes in pulse rate following exposures to particulate air pollution episodes. This study evaluated potential associations between daily measures of respirable particulate matter (PM) with pulse rate and oxygen saturation of the blood. Pulse rate and oxygen saturation (Spo2) using pulse oximetry were measured daily in 90 elderly subjects living near air pollution monitors during the winter of 1995-96 in Utah Valley. We also evaluated potential associations of oxygen saturation and pulse rate with barometric pressure. Small but statistically significant positive associations between day-to-day changes in Spo2 and barometric pressure were observed. Pulse rate was inversely associated with barometric pressure. Exposure to particulate pollution was not significantly associated with Spo2 except in male participants 80 years of age or older. Increased daily pulse rate, as well as the odds of having a pulse rate 5 or 10 beats per minute (bpm) above normal (normal is defined as the individual's mean pulse rate throughout the study period), were significantly associated with exposure to particulate pollution on the previous 1 to 5 days. The medical or biologic relevance of these increases in pulse rate following exposure to particulate air pollution requires further study. PMID:10192116

  18. Dosimetric Effects of Air Pockets Around High-Dose Rate Brachytherapy Vaginal Cylinders

    SciTech Connect

    Richardson, Susan; Palaniswaamy, Geethpriya; Grigsby, Perry W.

    2010-09-01

    Purpose: Most physicians use a single-channel vaginal cylinder for postoperative endometrial cancer brachytherapy. Recent published data have identified air pockets between the vaginal cylinders and the vaginal mucosa. The purpose of this research was to evaluate the incidence, size, and dosimetric effects of these air pockets. Methods and Materials: 25 patients receiving postoperative vaginal cuff brachytherapy with a high-dose rate vaginal cylinders were enrolled in this prospective data collection study. Patients were treated with 6 fractions of 200 to 400 cGy per fraction prescribed at 5 mm depth. Computed tomography simulation for brachytherapy treatment planning was performed for each fraction. The quantity, volume, and dosimetric impact of the air pockets surrounding the cylinder were quantified. Results: In 25 patients, a total of 90 air pockets were present in 150 procedures (60%). Five patients had no air pockets present during any of their treatments. The average number of air pockets per patient was 3.6, with the average total air pocket volume being 0.34 cm{sup 3} (range, 0.01-1.32 cm{sup 3}). The average dose reduction to the vaginal mucosa at the air pocket was 27% (range, 9-58%). Ten patients had no air pockets on their first fraction but air pockets occurred in subsequent fractions. Conclusion: Air pockets between high-dose rate vaginal cylinder applicators and the vaginal mucosa are present in the majority of fractions of therapy, and their presence varies from patient to patient and fraction to fraction. The existence of air pockets results in reduced radiation dose to the vaginal mucosa.

  19. Infiltration Model for Center Pivot Sprinkler Irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The marked reduction in infiltration rate caused by formation of a soil surface seal due to water droplet impact on bare soil is a well known phenomenon but is rarely considered in infiltration models, especially under center pivot irrigation. The objective of this study was to develop a soil infil...

  20. 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.

  1. Two-phase flow numerical simulation of infiltration and groundwater drainage in a rice field

    NASA Astrophysics Data System (ADS)

    Lugomela, G. V.

    Farming of rice normally uses a substantially larger amount of water than other cereal grain crops mainly due to the traditional flooding of rice fields. Flooding of the fields result in a seepage flow condition whereby infiltration occurs at a potential rate. The potential infiltration rate obstructs the free movement of pore-air through the ground surface and gradually compresses the pore-air between the infiltrating wetting front and the groundwater table under which subsurface drains are installed. The Galerkin finite element method (FEM) simulation of two-phase flow of air and water in the porous media of the rice field shows that the subsequent increase in the pore-air pressure makes the pore-air act as a link phase which transfers the effects of the processes taking place in the wetting front above and the saturated zone below the groundwater table. This phenomenon is clearly demonstrated when the results of the two-phase flow simulation are compared to the corresponding single-phase flow simulation which neglects the effect of the pore-air. It is concluded that the ‘ponding’ which appears in rice fields can partly be explained by the resistance offered by the pore-air to the percolation process. The study demonstrates that flooding of rice fields during most of its growth time is not necessary rather it is enough to keep the ground surface just saturated and the rest of the water can be saved.

  2. Sensitivity of long-term bare soil infiltration simulations to hydraulic properties in an arid environment

    NASA Astrophysics Data System (ADS)

    Stothoff, Stuart A.

    1997-04-01

    The suitability of Yucca Mountain, Nevada, for emplacement of a high-level nuclear waste geologic repository is currently being evaluated. Assessments of the repository performance suggest that the uncertainty in infiltration rates strongly affects predicted repository performance. Most of the ground surface over the potential repository footprint is characterized by shallow to deep colluvium/alluvium overlying densely fractured, welded tuffs. In order to identify characteristic behavior of infiltration that might be expected at the site, two idealizations of this situation are examined: an effectively semi-infinite column of alluvium and a two-layer column of alluvium over a fractured impermeable matrix. For each idealization the impact of hydraulic properties is assessed. Examining the sensitivity of bare soil simulator predictions for an effectively semi-infinite column, it is found that decreasing the air entry pressure while holding all other parameters at a fixed level tends to increase both the long-term average moisture content and the long-term average net infiltration flux for homogeneous media. In contrast, increasing the van Genuchten scale parameter (m=1 - 17sol;n) or decreasing the porosity tends to decrease the average soil moisture but increase the infiltration. Most interestingly, three regimes are found for permeability. For relatively high permeabilities, there is a trend toward increasing average infiltration and increasing average moisture content with decreasing permeability. For relatively low permeabilities, vapor transport dominates over liquid transport, runoff and evaporation overwhelm infiltration, and the soil becomes very dry with essentially no infiltration flux. Between the extreme cases of high and low permeability, there is a zone where decreasing permeability results in decreased infiltration but increased moisture content, which is explained by the capacity of more permeable media to maintain surface wetness for longer periods of

  3. Infiltration characteristics of bare soil under sequential water application events

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The marked reduction in infiltration rate caused by formation of a soil surface seal is a well known phenomenon but often ignored in infiltration models. The effect sequential water application events have on infiltration rate and soil surface seal formation has rarely been investigated. The objecti...

  4. 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...

  5. Hereditary Diffuse Infiltrating Retinoblastoma.

    PubMed

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

    2016-03-01

    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. PMID:24892564

  6. 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.

  7. Reaction rate constant for dry air oxidation of K Basin fuel

    SciTech Connect

    Trimble, D.J.

    1998-04-29

    The rate of oxidation of spent nuclear fuel stored in the K Basin water is an important parameter when assessing the processes and accident scenarios for preparing the fuel for dry storage. The literature provides data and rate laws for the oxidation of unirradiated uranium in various environments. Measurement data for the dry air oxidation of K Basin fuel is compared to the literature data for linear oxidation in dry air. Equations for the correlations and statistical bounds to the K Basin fuel data and the literature data are selected for predicting nominal and bounding rates for the dry air oxidation of the K Basin fuel. These rate equations are intended for use in the Spent Nuclear Fuel Project Technical Data book.

  8. Infiltration into soils: Conceptual approaches and solutions

    NASA Astrophysics Data System (ADS)

    Assouline, Shmuel

    2013-04-01

    Infiltration is a key process in aspects of hydrology, agricultural and civil engineering, irrigation design, and soil and water conservation. It is complex, depending on soil and rainfall properties and initial and boundary conditions within the flow domain. During the last century, a great deal of effort has been invested to understand the physics of infiltration and to develop quantitative predictors of infiltration dynamics. Jean-Yves Parlange and Wilfried Brutsaert have made seminal contributions, especially in the area of infiltration theory and related analytical solutions to the flow equations. This review retraces the landmark discoveries and the evolution of the conceptual approaches and the mathematical solutions applied to the problem of infiltration into porous media, highlighting the pivotal contributions of Parlange and Brutsaert. A historical retrospective of physical models of infiltration is followed by the presentation of mathematical methods leading to analytical solutions of the flow equations. This review then addresses the time compression approximation developed to estimate infiltration at the transition between preponding and postponding conditions. Finally, the effects of special conditions, such as the presence of air and heterogeneity in soil properties, on infiltration are considered.

  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. 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

  11. On the accuracy of the rate coefficients used in plasma fluid models for breakdown in air

    NASA Astrophysics Data System (ADS)

    Kourtzanidis, Konstantinos; Raja, Laxminarayan L.

    2016-07-01

    The electrical breakdown of air depends on the balance between creation and loss of charged particles. In fluid models, datasets of the rate coefficients used are obtained either from fits to experimental data or by solutions of the Boltzmann equation. Here, we study the accuracy of the commonly used models for ionization and attachment frequencies and their impact on the prediction of the breakdown threshold for air. We show that large errors can occur depending on the model and propose the most accurate dataset available for modeling of air breakdown phenomena.

  12. 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 ...

  13. Long-term dynamics of death rates of emphysema, asthma, and pneumonia and improving air quality

    PubMed Central

    Kravchenko, Julia; Akushevich, Igor; Abernethy, Amy P; Holman, Sheila; Ross, William G; Lyerly, H Kim

    2014-01-01

    Background The respiratory tract is a major target of exposure to air pollutants, and respiratory diseases are associated with both short- and long-term exposures. We hypothesized that improved air quality in North Carolina was associated with reduced rates of death from respiratory diseases in local populations. Materials and methods We analyzed the trends of emphysema, asthma, and pneumonia mortality and changes of the levels of ozone, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and particulate matters (PM2.5 and PM10) using monthly data measurements from air-monitoring stations in North Carolina in 1993–2010. The log-linear model was used to evaluate associations between air-pollutant levels and age-adjusted death rates (per 100,000 of population) calculated for 5-year age-groups and for standard 2000 North Carolina population. The studied associations were adjusted by age group-specific smoking prevalence and seasonal fluctuations of disease-specific respiratory deaths. Results Decline in emphysema deaths was associated with decreasing levels of SO2 and CO in the air, decline in asthma deaths–with lower SO2, CO, and PM10 levels, and decline in pneumonia deaths–with lower levels of SO2. Sensitivity analyses were performed to study potential effects of the change from International Classification of Diseases (ICD)-9 to ICD-10 codes, the effects of air pollutants on mortality during summer and winter, the impact of approach when only the underlying causes of deaths were used, and when mortality and air-quality data were analyzed on the county level. In each case, the results of sensitivity analyses demonstrated stability. The importance of analysis of pneumonia as an underlying cause of death was also highlighted. Conclusion Significant associations were observed between decreasing death rates of emphysema, asthma, and pneumonia and decreases in levels of ambient air pollutants in North Carolina. PMID:25018627

  14. Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

    NASA Astrophysics Data System (ADS)

    Weschler, Charles J.; Shields, Helen C.

    Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution of their particle size distributions. The experiments were performed in a manipulated office setting containing a constant source of d-limonene and an ozone generator that was remotely turned "on" or "off" at 6 h intervals. The particle number concentrations were monitored using an optical particle counter with eight-channels ranging from 0.1-0.2 to>2.0 μm diameter. The air exchange rates during the experiments were either high (working hours) or low (non-working hours) and ranged from 1.6 to>12 h -1, with intermediate exchange rates. Given the emission rates of ozone and d-limonene used in these studies, at an air exchange rate of 1.6 h -1 particle number concentration in the 0.1-0.2 μm size-range peaked 1.2 h after the ozone generator was switched on. In the ensuing 4.8 h particle counts increased in successive size-ranges up to the 0.5-0.7 μm diameter range. At higher air exchange rates, the resulting concentrations of total particles and particle mass (calculated from particle counts) were smaller, and at exchange rates exceeding 12 h -1, no excess particle formation was detectable with the instrument used in this study. Particle size evolved through accretion and, in some cases, coagulation. There was evidence for coagulation among particles in the smallest size-range at low air exchange rates (high particle concentrations) but no evidence of coagulation was apparent at higher air exchange rates (lower particle concentrations). At higher air exchange rates the particle count or size distributions were shifted towards smaller particle diameters and less time was required to achieve the maximum concentration in each of the size-ranges where discernable particle growth

  15. Modelling multiphase dynamics during infiltration using a pore network model

    NASA Astrophysics Data System (ADS)

    Tzavaras, Jannis; Arns, Ji-Youns; Max, Koehne; Hans-Joerg, Vogel

    2013-04-01

    We present an implementation of water infiltration into a pore network model where the local water pressures is continuously updated during the transient process. The network geometry is designed to represent structured soil which is different from simple granular porous media in some respect: Pores are more elongated and less isometric and the pore size distribution is much wider and structured hierarchically. To reproduce these properties, the classical concept of pore-bodies and throats is replaced by direct measurements of pore topology and the pores below the minimal pore size of the network model are represented by a continuous network of water saturated micro pores. The latter ensures that the water phase is always continuous which affects the propagation of the water potential during infiltration. The network model is based on cylindrical pores and considers capillary and gravitational forces. The propagation of interfaces is calculated for each time step by repeatedly solving the complete set of linear equation arising from Kirchhoff's law based on mass balance at each node of the network. This is done using the public domain package ITPack. The successive overrelaxation (SOR) and the Jacobi conjugate gradient (JCG) method proved to be more robust and faster than other solvers tested for the complex topology. The model accounts for entrapped air which is assumed to be incompressible. We present first results demonstrating the impact of external forcing (i.e infiltration rate) and pore topology on the dynamics of water-gas interfaces, the volume of entrapped air and hysteresis.

  16. Attenuation effects on the kerma rates in air after cesium depositions on grasslands.

    PubMed

    Jacob, P; Meckbach, R; Paretzke, H G; Likhtarev, I; Los, I; Kovgan, L; Komarikov, I

    1994-01-01

    Since the reactor accident of Chernobyl, cesium depth profiles and nuclide-specific kerma rates in air have been determined for various grassland sites in south Bavaria and in Ukraine. The sites are described by soil characteristics, annual precipitation, distance from release point, mode of deposition, and activity per unit area. The effects of surface roughness and migration of cesium into the soil on the kerma rate in air over grasslands was determined by two methods. The kerma rates in air obtained by the evaluations of in situ gamma-ray spectrometry results and of measured activity distributions in the soil showed only negligible differences for the observation period of 6 years after deposition. For the sites in Ukraine the kerma rate in air per activity per unit area was found to be systematically 40% higher than in Bavaria. The results from Bavaria on the attenuation of the kerma rate and a data set, including experiences from the weapons test fallout, are analytically approximated as a function of time up to 25 years after deposition. PMID:7809371

  17. Measurement of air exchange rates in residential and commercial buildings in the northwest: techniques and results

    SciTech Connect

    Parker, G.B.

    1985-04-01

    In a study of air exchange rates in commercial and residential buildings, several techniques were employed to measure the air exchange: analysis of sulfur hexafluoride tracer gas decay using a portable gas chromatograph; analysis of carbon monoxide decay using a continuous infrared analyzer; analysis of nitrogen oxides decay using a continuous oxides of nitrogen analyzer; and analysis of perfluorocarbon tracer (PFT) gas using a programmable automatic sampler, and a passive capillary tube sampler. Using sulfur hexafluoride tracer gas with real-time chromatography was the most labor-intensive method, requiring constant attention for several hours; whereas, analyzing the decay of PFT tracer gas using small capillary tubes required little setup time and virtually no attention. However, the analysis of tracer gas captured by the capillary tubes was difficult and was performed using special analysis equipment. The air exchange rate measured in the commercial buildings ranged from 5 to 0.04 air changes per hour (ACH) depending on the type of heating, ventilation, and air conditioning (HVAC) system. Air exchange in the residential structures ranged from about 1 ACH to about 0.3 ACH. 6 refs., 5 tabs., 3 figs.

  18. 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

  19. 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.

  20. 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 ...

  1. 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...

  2. Spray droplet sizes with additives discharged from an air-assisted variable-rate nozzle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding droplet size distributions is essential to achieve constant spray quality for real-time variable-rate sprayers that synchronize spray outputs with canopy structures. Droplet sizes were measured for a custom-designed, air-assisted, five-port nozzle coupled with a pulse width modulated (...

  3. 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...

  4. Influence of human activity patterns, particle composition, and residential air exchange rates on modeled distributions of PM2.5 exposure compared with central-site monitoring data.

    PubMed

    Baxter, Lisa K; Burke, Janet; Lunden, Melissa; Turpin, Barbara J; Rich, David Q; Thevenet-Morrison, Kelly; Hodas, Natasha; Ökaynak, Halûk

    2013-01-01

    Central-site monitors do not account for factors such as outdoor-to-indoor transport and human activity patterns that influence personal exposures to ambient fine-particulate matter (PM(2.5)). We describe and compare different ambient PM(2.5) exposure estimation approaches that incorporate human activity patterns and time-resolved location-specific particle penetration and persistence indoors. Four approaches were used to estimate exposures to ambient PM(2.5) for application to the New Jersey Triggering of Myocardial Infarction Study. These include: Tier 1, central-site PM(2.5) mass; Tier 2A, the Stochastic Human Exposure and Dose Simulation (SHEDS) model using literature-based air exchange rates (AERs); Tier 2B, the Lawrence Berkeley National Laboratory (LBNL) Aerosol Penetration and Persistence (APP) and Infiltration models; and Tier 3, the SHEDS model where AERs were estimated using the LBNL Infiltration model. Mean exposure estimates from Tier 2A, 2B, and 3 exposure modeling approaches were lower than Tier 1 central-site PM(2.5) mass. Tier 2A estimates differed by season but not across the seven monitoring areas. Tier 2B and 3 geographical patterns appeared to be driven by AERs, while seasonal patterns appeared to be due to variations in PM composition and time activity patterns. These model results demonstrate heterogeneity in exposures that are not captured by the central-site monitor. PMID:23321856

  5. 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.

  6. 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. PMID:24809924

  7. 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.

  8. 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.

  9. 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.

  10. The measurement of water vapour transfer rate through clothing system with air gap between layers

    NASA Astrophysics Data System (ADS)

    Oh, Ae-Gyeong

    2008-02-01

    The experiments described in this paper are designed to test the water vapour transfer rates through outdoor clothing system with air gap between layers under conditions more closely actual wear. It was adopted distance of 5 mm to ensure no disturbance of the air gap thickness between layers throughout the measurement period with all fabrics. The results have indicated that the water vapour transfer rates of clothing system decrease very slightly with time, it is shown that they approached nearly equilibrium state throughout the experiment. It is revealed that the water vapour transfer rates of the clothing system were ordered into groups determined by the type of waterproof breathable fabric as a shell layer being ordered.

  11. Infiltrative Hepatocellular Carcinoma

    PubMed Central

    Yan, Xiaopeng; Fu, Xu; Deng, Min; Chen, Jun; He, Jian; Shi, Jiong; Qiu, Yudong

    2016-01-01

    Abstract Data on infiltrative hepatocellular carcinoma (iHCC) receiving hepatectomy are unclear. Our study assessed the outcomes, effects of anatomical resection, and prognostic factors in a cohort of Chinese patients with iHCC undergoing hepatectomy. Data from 47 patients with iHCC undergoing hepatectomy were analyzed in a retrospective study. Independent prognostic factors of overall survival (OS) and recurrence-free survival (RFS) were identified using univariate and multivariate analyses. Correlations between microvascular invasion (MVI) and clinicopathological features were assessed using the χ2 test, Student t test, or the Mann–Whitney U test. Survival outcomes were estimated using the Kaplan-Meier method. The median OS was 27.37 months and the 1-year RFS rate were 61.7%. Alpha-fetoprotein (AFP) level was not a specific parameter in iHCC patients undergoing hepatectomy. Anatomic resection was significantly associated with increased RFS (P = 0.007). Patients showing MVI were observed with decreased RFS (P < 0.001). A high lactate dehydrogenase (LDH) level was significantly associated with decreased OS and RFS (P = 0.003 and P = 0.020, respectively). MVI was shown correlated with the levels of aspartate aminotransferase (AST), gamma glutamyl transpeptidase (GGT), and LDH. Subgroup analysis indicated that in mild MVI group, survival outcome was significantly more favorable in patients with high LDH level (P = 0.019). iHCC patients are related with higher MVI rate and patients may still derive survival benefit from anatomic resection at early and intermediate stages. MVI classification could be used to identify iHCC patients with a poorer survival, especially those with a high preoperative LDH level. PMID:27175659

  12. 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.

  13. 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.

  14. 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

  15. Age of air and heating rates: comparison of ERA-40 with ERA-Interim

    NASA Astrophysics Data System (ADS)

    Legras, B.; Fueglistaler, S.

    2009-04-01

    The age of air in the stratosphere is often used as a test for the good representation of the Brewer-Dobson circulation by atmospheric models. This is a critical requirement to modelize the distribution of long-lived species in chemical models. It is often advocated that using heating rates for vertical transport in the stratosphere performs better that standard analysed velocities from weather centers. This work is based on an extensive comparison of the age of air using 5 years of heating rates from the ERA-40 reanalysis and from the new ERA-interim reanalysis built with 4D-Var assimilation. The ERA-40 exhibits both too young ages with analyzed velocities and too old ages with heating rates. The reason for too young ages is spurious transport associated with too noisy wind, as a result of 3D-Var assimilation. Heating rates provide a much less noisy meridional circulation and preserve transport barriers and polar vortex confinement. However, excessive cooling near 30 hPa in the tropics blocks the ascending motion within the tropical pipe over extended periods of time inducing very old ages. This effect is usually corrected by an empirical correction which can exceed in some regions the calculated heating rate in magnitude, with opposite sign. We relate this correction to the assimilation temperature increment that is required to compensate the bias of the model, notably the excessive negative heat transport due to the noisy vertical velocities and the lack of mass conservation in the isentropic frame. The new ERA-interim exhibits much reduced noise in the vertical velocity and is ten times less diffusive than the ERA-40 in the tropics. Age of air is then found to be slightly older than given by the observations. The biases in the heating rate have also been considerably reduced with respect to ERA-40 and the assimilation increment is now only a fraction of the heating rate. The age of air is in fairly good aggreement with the observations at 20 km and higher

  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. 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. PMID:25827258

  18. 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.

  19. A Subgrid Model for Predicting Air Entrainment Rates in Bubbly Flows

    NASA Astrophysics Data System (ADS)

    Ma, Jingsen; Oberai, Assad A.; Drew, Donald E.; Lahey, Richard T., Jr.; Moraga, Francisco J.

    2008-11-01

    In this talk we present a fairly simple subgrid air entrainment model that accurately predicts the rate of air entrainment, which is critical in simulating multiphase (air/water) flows. The derivation of this model begins by assuming that a thin sheet of air is carried into the water by the inertia of the liquid at the free surface. A momentum balance on the entrained gas layer results in an expression for the entrained volumetric gas flow rate, in terms of the local liquid velocity, gas viscosity etc., which are readily available from a multiphase RANS-type simulation. This model has been validated against extensive experimental data on both plunging jets and hydraulic jumps over a wide range of liquid velocities. It was implemented in a two-fluid computational fluid dynamics code (CFDShipM) to be used to predict the void fraction distribution underneath a plunging liquid jet at different depths and jet velocities. The results were found to match the experimental observations very well. The application of this model to more challenging problems, including hydraulic jumps and full-scale ship simulations, is currently underway.

  20. 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.

  1. The energy impact of air leakage through insulated walls

    SciTech Connect

    Bhattacharyya, S.; Claridge, D.E.

    1995-08-01

    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 a well-characterized insulated stud-cavity wall specimen. Calorimetric measurements conducted on the specimen with measured amounts of air leakage introduced under a variety of controlled conditions and configurations verify earlier test cell measurements showing that infiltration heat exchange can lead to a much smaller change in the energy load due to infiltration than is customarily calculated and show the dependence of infiltration heat exchange on flow rate and path length. A analytical model based on fundamental heat and mass transfer principles has been developed and the predicted values of Infiltration Heat Exchange Effectiveness, {var_epsilon}, as a function of air flow rates and effective path length for five study-cavity wall specimen test configurations were consistent with the experimental results. Significant experimental results include: (i) {epsilon} values in the 0.16--0.7 range in the stud-cavity and (ii) {epsilon} values of 0.16 to 0.34 for air exiting the stud-cavity directly across from the entry. These results indicate that significant heat recovery is probable for most leakage occurring through insulated stud cavities.

  2. 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. PMID:24672332

  3. Analysis of Rainfall Infiltration Law in Unsaturated Soil Slope

    PubMed Central

    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. PMID:24672332

  4. Risk of sick leave associated with outdoor air supply rate, humidification, and occupant complaints.

    PubMed

    Milton, D K; Glencross, P M; Walters, M D

    2000-12-01

    We analyzed 1994 sick leave for 3,720 hourly employees of a large Massachusetts manufacturer, in 40 buildings with 115 independently ventilated work areas. Corporate records identified building characteristics and IEQ complaints. We rated ventilation as moderate (approximately 25 cfm/person, 12 ls-1) or high (approximately 50 cfm/person, 24 ls-1) outdoor air supply based on knowledge of ventilation systems and CO2 measurements on a subset of work areas, and used Poisson regression to analyze sick leave controlled for age, gender, seniority, hours of non-illness absence, shift, ethnicity, crowding, and type of job (office, technical, or manufacturing worker). We found consistent associations of increased sick leave with lower levels of outdoor air supply and IEQ complaints. Among office workers, the relative risk for short-term sick leave was 1.53 (95% confidence 1.22-1.92) with lower ventilation, and 1.52 (1.18-1.97) in areas with IEQ complaints. The effect of ventilation was independent of IEQ complaints and among those exposed to lower outdoor air supply rates the attributable risk of short-term sick leave was 35%. The cost of sick leave attributable to ventilation at current recommended rates was estimated as $480 per employee per year at Polaroid. These findings suggest that net savings of $400 per employee per year may be obtained with increased ventilation. Thus, currently recommended levels of outdoor air supply may be associated with significant morbidity, and lost productivity on a national scale could be as much as $22.8 billion per year. Additional studies of IEQ impacts on productivity and sick leave, and the mechanisms underlying the apparent association are needed. PMID:11089326

  5. 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

  6. Establishment of air kerma reference standard for low dose rate Cs-137 brachytherapy sources.

    PubMed

    Sharma, Sunil Dutt; Kumar, Sudhir; Srinivasan, P; Chourasiya, G

    2011-01-01

    A guarded cylindrical graphite ionization chamber of nominal volume 1000 cm3 was designed and fabricated for use as a reference standard for low-dose rate 137Cs brachytherapy sources. The air kerma calibration coefficient (N(K)) of this ionization chamber was estimated analytically using Burlin's general cavity theory, as well as by the Monte Carlo simulation and validated experimentally using Amersham CDCS-J-type 137Cs reference source. In the analytical method, the N(K) was calculated for 662 keV gamma rays of 137Cs brachytherapy source. In the Monte Carlo method, the geometry of the measurement setup and physics-related input data of the 137Cs source and the surrounding material were simulated using the Monte Carlo N-Particle code. The photon energy fluence was used to arrive at the reference air kerma rate (RAKR) using mass energy absorption coefficient. The energy deposition rates were used to simulate the value of charge rate in the ionization chamber, and the N(K) was determined. The analytical and Monte Carlo values of N(K) of the cylindrical graphite ionization chamber for 137Cs brachytherapy source are in agreement within 1.07%. The deviation of analytical and Monte Carlo values from experimental values of N(K) is 0.36% and 0.72%, respectively. This agreement validates the analytical value, and establishes this chamber as a reference standard for RAKR or AKS measurement of 137Cs brachytherapy sources. PMID:22089009

  7. 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. PMID:20948928

  8. 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. PMID:19044163

  9. 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.

  10. Distribution and variability of the 24-h average air exchange rates and interzonal flow rates in 26 Japanese residences in 5 seasons

    NASA Astrophysics Data System (ADS)

    Shinohara, Naohide; Kataoka, Toshiyuki; Takamine, Koichi; Gamo, Masashi

    2011-07-01

    In this study, to evaluate the distribution of air exchange rates in Japan, daily, seasonal, and inter-residence variabilities were determined as well as the air exchange rate itself. In addition, airflows among multiple zones were also evaluated. For this purpose, the 24 h average air exchange rates and interzonal air flow rates were measured using a passive perfluorocarbon tracer (PFT) method with three kinds of tracer gases for 1 week in three rooms of 26 Japanese residences over five seasons: summer and autumn of 2005, and winter, spring, and summer of 2006. During these seasons, the weekly average air exchange rates were found to be 1.6 ± 1.7, 0.58 ± 0.94, 0.61 ± 0.93, 1.2 ± 2.5, and 1.7 ± 1.8 h -1, respectively. Two-way repeated measure analysis of variance (ANOVA) revealed that the air exchange rates differed significantly with respect to the seasons, residences, and interaction of seasons and residences ( p < 0.01). In addition, the air exchange rates in both summers and spring were statistically higher than those in autumn and winter (Sheffe test, p < 0.01). According to the ANOVA, the percentage contribution of inter-residence variability, seasonal variability, interaction of seasonal and inter-residence variabilities, and daily variability to the total variability of the 24 h average air exchange rates in the present survey was 51%, 44%, 3.7%, and 1.0%, respectively.

  11. Reconfigurable photonic crystal waveguides created by selective liquid infiltration.

    PubMed

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

    2012-05-01

    We experimentally demonstrate reconfigurable photonic crystal waveguides created directly by infiltrating high refractive index (n≈2.01) liquids into selected air holes of a two-dimensional hexagonal periodic lattice in silicon. The resulting effective index contrast is large enough that a single row of infiltrated holes enables light propagation at near-infrared wavelengths. We include a detailed comparison between modeling and experimental results of single line defect waveguides and show how our infiltration procedure is reversible and repeatable. We achieve infiltration accuracy down to the single air hole level and demonstrate control on the volume of liquid infused into the holes by simply changing the infiltration velocity. This method is promising for achieving a wide range of targeted optical functionalities on a "blank" photonic crystal membrane that can be reconfigured on demand. PMID:22565727

  12. 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.

  13. Building characterization and aerosol infiltration into a naturally ventilated three-story apartment building.

    PubMed

    Rodes, Charles E; Vanosdell, Douglas W; Portzer, Jeffrey W; Seagraves, Jeremy; Hahn, Intaek; Henkle, Stacy W; Wiener, Russell W

    2009-12-01

    Understanding infiltration of outdoor pollutants was an integral part of the Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study. For this reason, the structural and air exchange properties of the three-story row house in Brooklyn, NY, USA, that was used in the B-TRAPPED experiments were fully characterized. Factors investigated included representativeness of the construction and impact of building design features on the natural ventilation and infiltration of outdoor aerosol. Both blower door and perfluorocarbon tracer (PFT) air exchange rate (AER) experiments showed that the ventilation rates of the building were quite typical of similar structures in the New York City (NYC) metropolitan area. Indoor/outdoor (I/O) aerosol count ratios by particle size were comparable to a similar vintage naturally ventilated building in Boston, MA, USA. I/O ratio analyses were consistent with literature findings and showed I/O ratios ranging from 0.310 to 0.601, varying across particle sizes (from 0.3 to 5.0 [corrected] mum) and between first and second floor apartments. An effort to apply the rebound method of Thatcher et al. (Aerosol Sci. Technol., 2003, 37, 847-864) in determining aerosol infiltration rates proved unsuccessful due to unexpectedly long (>60 min) equilibration times after the filtration period. Uninsulated interior wall renovations in the study house created a cavity that resulted in a large intermediate dead volume (for infiltration) that apparently could not be accommodated by a simple infiltration model. Simple two-compartment models evidently have finite application limitations for even modestly complex settings. PMID:20024015

  14. Evaluation of passive air sampler calibrations: Selection of sampling rates and implications for the measurement of persistent organic pollutants in air

    NASA Astrophysics Data System (ADS)

    Melymuk, Lisa; Robson, Matthew; Helm, Paul A.; Diamond, Miriam L.

    2011-04-01

    Polyurethane foam (PUF) passive air samplers (PAS) are a common and highly useful method of sampling persistent organic pollutants (POP) concentrations in air. PAS calibration is necessary to obtain reasonable and comparable semi-quantitative measures of air concentrations. Various methods are found in the literature concerning PAS calibration. 35 studies on PAS use and calibration are examined here, in conjunction with a study involving 10 PAS deployed concurrently in outdoor air with a low-volume air sampler in order to measure the sampling rates of PUF-PAS for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic musks (PCMs), and polycyclic aromatic hydrocarbons (PAHs). Based on this analysis it is recommended that (1) PAS should be assumed to represent bulk rather than gas-phase compound concentrations due to the sampling of particle-bound compounds, (2) calibration of PAS sampling rates is more accurately achieved using an active low-volume air sampler rather than depuration compounds since the former measures gas- and particle-phase compounds and does so continuously over the deployment period of the PAS, and (3) homolog-specific sampling rates based on KOA groupings be used in preference to compound/congener-specific or single sampling rates.

  15. Ambient temperature, air pollution, and heart rate variability in an aging population.

    PubMed

    Ren, Cizao; O'Neill, Marie S; Park, Sung Kyun; Sparrow, David; Vokonas, Pantel; Schwartz, Joel

    2011-05-01

    Studies show that ambient temperature and air pollution are associated with cardiovascular disease and that they may interact to affect cardiovascular events. However, few epidemiologic studies have examined mechanisms through which ambient temperature may influence cardiovascular function. The authors examined whether temperature was associated with heart rate variability (HRV) in a Boston, Massachusetts, study population and whether such associations were modified by ambient air pollution concentrations. The population was a cohort of 694 older men examined between 2000 and 2008. The authors fitted a mixed model to examine associations between temperature and air pollution and their interactions with repeated HRV measurements, adjusting for covariates selected a priori on the basis of their previous studies. Results showed that higher ambient temperature was associated with decreases in HRV measures (standard deviation of normal-to-normal intervals, low-frequency power, and high-frequency power) during the warm season but not during the cold season. These warm-season associations were significantly greater when ambient ozone levels were higher (>22.3 ppb) but did not differ according to levels of ambient fine (≤2.5 μm) particulate matter. The authors conclude that temperature and ozone, exposures to both of which are expected to increase with climate change, might act together to worsen cardiovascular health and/or precipitate cardiovascular events via autonomic nervous system dysfunction. PMID:21385834

  16. 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.

  17. Evaluation of Burning Test Rate Method for Flammable Solids to Increase air-Cargo Safety.

    PubMed

    Lukežič, Marjan; Marinšek, Marjan; Faganeli, Jadran

    2010-03-01

    This paper deals with a standard classification procedure for readily combustible solids and their assignment to the relevant packing groups according to international air-cargo legislation and regulations. The current International Air Transport Association and United Nations Orange Book regulations were used on chemically similar substances: hexamethylenetetramine and Dancook ignition briquettes, which are both assigned into the same Packing Group III. To critically evaluate the degree of hazard both chemicals present, a standard burning test rate as well as thermogravimetry, differential scanning calorimetry and evolved gas analysis measurements were performed. It was shown that relatively small changes in the chemical composition of the material may have essential influence on the package group determination. Taking into account all the facts collected in the experimental work, it was concluded that ignition briquettes will undergo spontaneous combustion if exposed to elevated temperatures and, from this point of view, represent higher risk than hexamethylenetetramine during air transportation. Therefore, ignition briquettes should be classified into Packing Group II. PMID:24061664

  18. 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

  19. 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.

  20. Field observations of turbulent dissipation rate profiles immediately below the air-water interface

    NASA Astrophysics Data System (ADS)

    Wang, Binbin; Liao, Qian

    2016-06-01

    Near surface profiles of turbulence immediately below the air-water interface were measured with a free-floating Particle Image Velocimetry (PIV) system on Lake Michigan. The surface-following configuration allowed the system to measure the statistics of the aqueous-side turbulence in the topmost layer immediately below the water surface (z≈0˜15 cm, z points downward with 0 at the interface). Profiles of turbulent dissipation rate (ɛ) were investigated under a variety of wind and wave conditions. Various methods were applied to estimate the dissipation rate. Results suggest that these methods yield consistent dissipation rate profiles with reasonable scattering. In general, the dissipation rate decreases from the water surface following a power law relation in the top layer, ɛ˜z-0.7, i.e., the slope of the decrease was lower than that predicted by the wall turbulence theory, and the dissipation was considerably higher in the top layer for cases with higher wave ages. The measured dissipation rate profiles collapse when they were normalized with the wave speed, wave height, water-side friction velocity, and the wave age. This scaling suggests that the enhanced turbulence may be attributed to the additional source of turbulent kinetic energy (TKE) at the "skin layer" (likely due to micro-breaking), and its downward transport in the water column.

  1. 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.

  2. Effect of surfactants on the rate of growth of an air bubble by rectified diffusion.

    PubMed

    Lee, Judy; Kentish, Sandra; Ashokkumar, Muthupandian

    2005-08-01

    The rectified diffusion growth of a single air bubble levitated in an acoustic field (frequency = 22.35 kHz) in water and in aqueous solutions containing surfactants (sodium dodecyl sulfate and sodium dodecylbenzene sulfonate) was investigated. As reported by Crum (J. Acoust. Soc. Am. 1980, 68, 203), the presence of surfactants at the bubble/liquid interface enhanced the growth rate of the bubble by rectified diffusion. It is suggested in this paper that in addition to the effect of surfactants on the surface tension and interfacial resistance to mass transfer, the effect of surface rheological properties may also contribute to the cause of the enhancement observed in the bubble growth rate. PMID:16852840

  3. Effects of air oxidation on the dissolution rate of LWR spent fuel

    SciTech Connect

    Gray, W.J.; Thomas, L.E.; Einziger, R.E.

    1993-12-31

    Dissolution rates for air-oxidized spent fuel were measured in flowthrough tests where U concentrations were kept well below the solubility limit. Results from two types of specimens, separated grains and coarse particles, both in oxidized (U{sub 4}O{sub 9+x}) and unoxidized (UO{sub 2}) conditions indicated only minor effects of oxidation on the surface-area-normalized rates. Similar results were obtained for unirradiated specimens in three different oxidation states (UO{sub 2}, U{sub 3}O{sub 7}, and U{sub 3}O{sub 8}). These observations have important practical implications for disposal of spent fuel in a geologic repository as well as implications regarding the oxidative dissolution mechanism of UO{sub 2} fuel.

  4. 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.

  5. 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…

  6. Biofiltration of air contaminated by styrene: Effect of nitrogen supply, gas flow rate, and inlet concentration

    SciTech Connect

    Jorio, H.; Bibeau, L.; Heitz, M.

    2000-05-01

    The biofiltration process is a promising technology for the treatment of dilute styrene emissions in air. The efficiency of this process is however strongly dependent upon various operational parameters such as the filter bed characteristics, nutrient supplies, input contaminant concentrations, and gas flow rates. The biofiltration of air containing styrene vapors was therefore investigated, employing a novel biomass filter material, in two identical but separate laboratory scale biofiltration units (units 1 and 2), both biofilters being initially inoculated with a microbial consortium. Each biofilter was irrigated with a nutrient solution supplying nitrogen in one of two forms; i.e., mainly as ammonia for unit 1 and exclusively as nitrate for unit 2. The experimental results have revealed that greater styrene elimination rates are achieved in the biofilter supplied with ammonia as the major nitrogen source in comparison to the lesser elimination performance obtained with the nitrate provided biofilter. However, in achieving the high styrene removal rates in the ammonia supplied biofilter, the excess of biomass accumulates on the filtering pellets and causes progressive clogging of the filter media. Furthermore, the effectiveness of nitrate supply as the sole nitrogen nutrient form, on reducing or controlling the biomass accumulation in the filter media in comparison to ammonia, could not be satisfactorily demonstrated because the two biofilters operated with very different styrene elimination capacities. The monitoring of the carbon dioxide concentration profile through both biofilters revealed that the ratio of carbon dioxide produced to the styrene removed was approximately 3/1, which confirms the complete biodegradation of removed styrene, given that some of the organic carbon consumed is also used for the microbial growth. The effects of the most important design parameters, namely styrene input concentrations and gas flow rates, were investigated for each

  7. 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

  8. Safety management of nuclear medicine personnel with visualisation of air dose rate.

    PubMed

    Kawase, S; Ohno, K; Nakamoto, Y; Miyatake, H

    2015-07-01

    Many people are anxious about radiation exposure for the reason that radiation cannot be seen. With the aim of devising a way for medical personnel to perform their medical duties without worry about radiation exposure, we attempted safety management using a system that displays the air dose of radiation in real time. Measurements were made in a lung ventilation scintigraphy examination room with the use of Xe-133. An SCI-type RI detector from Hamamatsu Photonics, which displays the air dose rate in real time, was used for the measurements. These radiation measurements were continued from the start to finish of the examination. The measurements were made in two locations, on the patient inhalation tube side and on the opposite side. Measurements were made on the patient tube side in 24 tests and on the opposite side in 12 tests. The maximum air dose rate was 3.7 ± 2.1 μSv/h on the patient tube side and 1.1 ± 0.5 μSv/h on the opposite side. Thus, the level on the opposite side was about 1/5 that of the tube side. To accurately perform lung ventilation scintigraphy, a medical worker needs to observe the patient's breathing status up close. Because of this, some medical workers are worried about radiation exposure during tests. The simplest way to reduce exposure would be to maintain a distance from the examination tube that is the source of radiation. The measurements in this study were made to encourage medical workers' recognition of this fact. Displaying specific numbers not only serves as basic data for managing staff operations, but is also thought to reassure workers through visualization. PMID:25889608

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. Radiative and turbulent heating rates in the clear-air boundary layer

    NASA Astrophysics Data System (ADS)

    Savijärvi, Hannu

    2006-01-01

    The diurnal evolution of a clear-sky midlatitude summertime boundary layer (BL) was studied using a column model over smooth and homogeneous land, subject to weak, moderate, and strong winds. The high-resolution BL model (lowest point at 30 cm) was equipped with an adequate turbulence scheme and a narrow-band long-wave (LW) radiation scheme, the latter validated using data from the International Comparison of Radiation Codes in Climate Models (ICRCCM).In off-line ICRCCM experiments, ground emissivity ɛ < 1 led to extra LW cooling of air near the surface compared to ɛ = 1. However, much stronger LW cooling at heights of 1 3 m, and warming below 1 m, was obtained by setting the ground colder than air at screen height, a typical condition during clear nights. Conversely, a warm surface anomaly typical of sunny days leads to strong LW warming at 1 3 m, with LW cooling just above the ground. These ground temperature anomalies dominated the LW heating/cooling patterns at heights of up to 3 4 m, perhaps explaining controversies in the observed LW flux divergences close to the ground.Interactive model results indicate that the middle part of a windy clear-air nocturnal BL (NBL) is dominated by turbulent cooling, while the upper and lower NBL is dominated by LW cooling. Below about 1 m, a fourth layer is formed with LW warming and turbulent cooling, in agreement with the off-line experiments. When the surface winds fall below about 1 1.5 m s -1 LW cooling dominates in the whole NBL, except very near the surface. In these light wind conditions the Monin Obukhov theory should be revised to include radiative effects.In clear-air daytime conditions strong convective BL heating dominates over weak LW cooling except at 1 3 m heights where the cooler air absorbs the thermal emission of the hot ground. The subsequent LW warming of the superadiabatic surface layer appears to be strong enough to induce local turbulent cooling (despite the hot surface) in an 'hour glass' pattern

  15. The effects of outdoor air supply rate in an office on perceived air quality, sick building syndrome (SBS) symptoms and productivity.

    PubMed

    Wargocki, P; Wyon, D P; Sundell, J; Clausen, G; Fanger, P O

    2000-12-01

    Perceived air quality, Sick Building Syndrome (SBS) symptoms and productivity were studied in a normally furnished office space (108 m3) ventilated with an outdoor airflow of 3, 10 or 30 L/s per person, corresponding to an air change rate of 0.6, 2 or 6 h-1. The temperature of 22 degrees C, the relative humidity of 40% and all other environmental parameters remained unchanged. Five groups of six female subjects were each exposed to the three ventilation rates, one group and one ventilation rate at a time. Each exposure lasted 4.6 h and took place in the afternoon. Subjects were unaware of the intervention and remained thermally neutral by adjusting their clothing. They assessed perceived air quality and SBS symptoms at intervals, and performed simulated normal office work. Increasing ventilation decreased the percentage of subjects dissatisfied with the air quality (P < 0.002) and the intensity of odour (P < 0.02), and increased the perceived freshness of air (P < 0.05). It also decreased the sensation of dryness of mouth and throat (P < 0.0006), eased difficulty in thinking clearly (P < 0.001) and made subjects feel generally better (P < 0.0001). The performance of four simulated office tasks improved monotonically with increasing ventilation rates, and the effect reached formal significance in the case of text-typing (P < 0.03). For each two-fold increase in ventilation rate, performance improved on average by 1.7%. This study shows the benefits for health, comfort and productivity of ventilation at rates well above the minimum levels prescribed in existing standards and guidelines. It confirms the results of a previous study in the same office when the indoor air quality was improved by decreasing the pollution load while the ventilation remained unchanged. PMID:11089327

  16. 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. PMID:2306364

  17. 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.

  18. 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

  19. 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.

  20. Hydrocarbon Observations and Ozone Production Rates in Western Houston During the Texas 2000 Air Quality Study

    SciTech Connect

    Berkowitz, Carl M.; Spicer, Chet W.; Doskey, Paul V.

    2005-06-01

    Measurements of total non-methane hydrocarbon in whole air canisters collected from the top of a skyscraper on the western edge of Houston, Texas are summarized with an emphasis on samples collected during the passage of plumes of O{sub 3} and the associated rapid increase in the mixing ratio of this species. The back-trajectories associated with these events showed a pronounced deceleration of air parcels over central and western Houston and were not necessarily associated with direct passage over the petrochemical plants located in the heavily industrialized eastern part of Houston. As a result of the time these air parcels spent over the central and western parts of Houston, their VOC mix and associated chemical production rates were expected to differ from similar observations made over eastern Houston from aircraft sampling at low altitudes. Although periods of high O{sub 3} in the western part of the city were closely associated with light alkenes, these same observations show isoprene to make a significant contribution to the total VOC reactivity in the early afternoon (the start of peak photochemical activity) in contrast to observations made east of our sampling site that found the reactivity to be dominated by anthropogenic species. By initializing a 0-dimensional chemical kinetic model with observations made at the Williams Tower, we find that the ozone production efficiency scaled linearly to the ratio of total hydrocarbons and NO{sub x}, with an average OPE of 7.2, ranging from 2.3 to 16.9; these values are smaller than those reported in eastern Houston, suggesting a strong gradient in photochemical productivity across the city.

  1. Indoor Air Pollution, Nighttime Heart Rate Variability and Coffee Consumption among Convenient Store Workers

    PubMed Central

    Chuang, Kai-Jen; Chuang, Hsiao-Chi; Lin, Lian-Yu

    2013-01-01

    Background The association between ambient air pollution and heart rate variability (HRV) has been well-documented. Little is known about the association of HRV at night with indoor air pollution and coffee consumption. The aim of this study was to investigate the association of HRV indices with indoor air pollution, working time and coffee consumption. Methods We recruited 60 young healthy convenient store workers to monitor indoor PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 µm) exposures, coffee consumption (yes vs. no) and HRV indices during daytime (0700–1500 hours) and nighttime (2300-0700 hours). We used linear mixed effects models to assess the associations of HRV indices with indoor PM2.5 exposures and coffee consumption. Results We observed the inverse association between indoor PM2.5 exposures and HRV indices, with a decrease in all HRV indices with increased indoor PM2.5 exposures. However, the decrease was most pronounced during nighttime, where a 1 interquartile range (IQR) increase in indoor PM2.5 at 4-hr time-weighted moving average was associated with a change of −4.78% 5-min standard deviation (SD) of normal-to-normal intervals for 5-min segment (SDNN) and −3.23% 5-min square root of the mean squared differences of successive intervals for 5-min segment (r-MSSD). Effects of indoor PM2.5 were lowest for participants with coffee consumption during daytime. Conclusions Indoor PM2.5 exposures were associated with decreased 5-min SDNN and 5-min r-MSSD, especially during nighttime. The effect of indoor PM2.5 on HRV indices may be modified by coffee consumption in young healthy convenient store workers. PMID:24312680

  2. 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.

  3. An experimental investigation on the effects of surface gravity waves on the water evaporation rate in different air flow regimes

    NASA Astrophysics Data System (ADS)

    Jodat, Amin; Moghiman, Mohammad; Shirkhani, Golshad

    2013-12-01

    Estimating rate of evaporation from undisturbed water surfaces to moving and quiet air has been the topic a vast number of research activities. The obvious presence of various shapes of gravity waves on the water body surfaces was the motivation of this experimental investigation. In this investigation experimental measurements have been done to quantify evaporation rate from wavy water surfaces in free, mixed and forced convection regimes. The effects of a wide range of surface gravity waves from low steepness, round shaped crest with slow celerity, to steep and very slight spilling crest waves, on the water evaporation rate have been investigated. A wide range of was achieved by applying different air flow velocities on a large heated wave flume equipped with a wind tunnel. Results reveal that wave motion on the water surface increase the rate of evaporation for all air flow regimes. For free convection, due to the effect of wave motion for pumping rotational airflows at the wave troughs and the dominant effect of natural convection for the air flow advection, the maximum evaporation increment percentage from wavy water surface is about 70 %. For mixed and forced convection, water evaporation rate increment is more sensitive to the air flow velocity for the appearance of very slight spilling on the steep wave crests and the leeward air flow structures.

  4. Effects of oblique air flow on burning rates of square ethanol pool fires.

    PubMed

    Tao, Changfa; He, Yaping; Li, Yuan; Wang, Xishi

    2013-09-15

    The effects of downward airflow on the burning rate and/or burning intensity of square alcohol pool fires for different airflow speeds and directions have been studied experimentally in an inclined wind tunnel. An interesting flame-wrapping phenomenon, caused by impingement of air flow, was observed. The mass burning intensity was found to increase with the airflow speed and the impinging angle. The fuel pan rim temperatures were also measured to study the effect of wind direction and speed on heat transfer from the flame to the fuel source. A model based on heat transfer analysis was developed to correlate the burning intensity with the pan rim characteristic temperature. A good correlation was established between the model results and the experimental results. PMID:23811377

  5. 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.

  6. Infiltration Flow Path Distributions in Unsaturated Rocks

    NASA Astrophysics Data System (ADS)

    Tokunaga, T. K.; Olson, K. R.; Wan, J.

    2004-12-01

    Spatial distributions of infiltration flow paths through rock formations are complex networks that determine flow velocities, control rates of natural geochemical reactions in the subsurface, as well as rates of contaminant transport to underlying groundwater. Despite these important consequences, distributions of infiltration paths and locally fast seepage rates through rocks are not well understood. Laboratory-based studies on fractured rocks cannot easily be conducted on systems large enough to include sufficient fracture network complexity, so that inferences of field-scale flux distributions cannot be reliably made. Field-based studies to date have permitted quantification of only a small fraction of the flow distribution, typically while imposing extremely high fluxes, and therefore have not allowed comprehensive delineation of flow distributions expected under natural recharge. Based on hydraulic scaling considerations, we hypothesize that unsaturated flow path distributions in rock deposits will be similar to those occurring in fractured rock formations under low overall infiltration rates. Talus rock deposits and mine waste rock piles control flow and transport into their respective underlying groundwaters. All of these reasons motivated infiltration experiments in rock packs. Experiments have been conducted on 4 different rock types and system scales ranging from 1 to 46 rock layers. Our experiments showed that infiltration through rocks conforms to no previously reported behavior in soils, and that flow paths do not progressively converge into fewer and fewer flow paths. Instead, a fundamentally different hydraulic structure develops, having an exponential (geometric) flux distribution, with the characteristic scale determined by the characteristic rock size. Although the phenomena are very different, the evolution of flow path distributions and local seepage rate distributions is predictable based on a statistical mechanical model for energy

  7. Infiltration model for center pivot irrigation on bare soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The marked reduction in infiltration rate caused by formation of a soil surface seal due to water droplet impact on bare soil is a well known phenomenon but is rarely considered in infiltration models, especially under center pivot irrigation. The objective of this study was to develop a soil infil...

  8. 40 CFR 35.927-1 - Infiltration/inflow analysis.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-1... estimated total costs for transportation and treatment of the infiltration/inflow. Cost-effectiveness... presence, flow rate, and type of infiltration/inflow conditions which exist in the sewer system. (b)...

  9. 40 CFR 35.927-1 - Infiltration/inflow analysis.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-1... estimated total costs for transportation and treatment of the infiltration/inflow. Cost-effectiveness... presence, flow rate, and type of infiltration/inflow conditions which exist in the sewer system. (b)...

  10. 40 CFR 35.927-1 - Infiltration/inflow analysis.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-1... estimated total costs for transportation and treatment of the infiltration/inflow. Cost-effectiveness... presence, flow rate, and type of infiltration/inflow conditions which exist in the sewer system. (b)...

  11. 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. PMID:11282319

  12. The association of particulate air metal concentrations with heart rate variability.

    PubMed Central

    Magari, Shannon R; Schwartz, Joel; Williams, Paige L; Hauser, Russ; Smith, Thomas J; Christiani, David C

    2002-01-01

    Numerous studies show an association between particulate air pollution and adverse health effects. Particulate matter is a complex mixture of elemental carbon, ammonium, sulfates, nitrates, organic components, and metals. The mechanisms of action of particulate matter less than or equal to 2.5 micro m in mean aerodynamic diameter (PM(2.5)), as well as the constituents responsible for the observed cardiopulmonary health effects, have not been identified. In this study we focused on the association between the metallic component of PM(2.5) and cardiac autonomic function based on standard heart rate variability (HRV) measures in an epidemiologic study of boilermakers. Thirty-nine male boilermakers were monitored throughout a work shift. Each subject wore an ambulatory electrocardiogram (Holter) monitor and a personal monitor to measure PM(2.5). We used mixed-effects models to regress heart rate and SDNN index (standard deviation of the normal-to-normal) on PM(2.5) and six metals (vanadium, nickel, chromium, lead, copper, and manganese). There were statistically significant mean increases in the SDNN index of 11.30 msec and 3.98 msec for every 1 micro g/m(3) increase in the lead and vanadium concentrations, respectively, after adjusting for mean heart rate, age, and smoking status. Small changes in mean heart rate were seen with all exposure metrics. The results of this study suggest an association between exposure to airborne metals and significant alterations in cardiac autonomic function. These results extend our understanding of the adverse health effects of the metals component of ambient PM(2.5). PMID:12204821

  13. Childhood cancer incidence rates and hazardous air pollutants in California: an exploratory analysis.

    PubMed Central

    Reynolds, Peggy; Von Behren, Julie; Gunier, Robert B; Goldberg, Debbie E; Hertz, Andrew; Smith, Daniel F

    2003-01-01

    Hazardous air pollutants (HAPs) are compounds shown to cause cancer or other adverse health effects. We analyzed population-based childhood cancer incidence rates in California (USA) from 1988 to 1994, by HAP exposure scores, for all California census tracts. For each census tract, we calculated exposure scores by combining cancer potency factors with outdoor HAP concentrations modeled by the U.S. Environmental Protection Agency. We evaluated the relationship between childhood cancer rates and exposure scores for 25 potentially carcinogenic HAPs emitted from mobile, area, and point sources and from all sources combined. Our study period saw 7,143 newly diagnosed cancer cases in California; of these, 6,989 (97.8%) could be assigned to census tracts and included in our analysis. Using Poisson regression, we estimated rate ratios (RRs) adjusted for age, race/ethnicity, and sex. We found little evidence for elevated cancer RRs for all sites or for gliomas among children living in high-ranking combined-source exposure areas. We found elevated RRs and a significant trend with increasing exposure level for childhood leukemia in tracts ranked highest for exposure to the combined group of 25 HAPs (RR = 1.21; 95% confidence interval, 1.03, 1.42) and in tracts ranked highest for point-source HAP exposure (RR = 1.32; 95% confidence interval, 1.11, 1.57). Our findings suggest an association between increased childhood leukemia rates and high HAP exposure, but studies involving more comprehensive exposure assessment and individual-level exposure data will be important for elucidating this relationship. PMID:12676632

  14. 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....

  15. 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'.

  16. 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)...

  17. 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. PMID:24401556

  18. 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.

  19. Uneven Futures of Human Lifespans: Reckonings from Gompertz Mortality Rates, Climate Change, and Air Pollution

    PubMed Central

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

    2014-01-01

    The past 200 years have enabled remarkable increases in human lifespans thru improvements of 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 Jean 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 C cohorts would require 50% slower mortality rate accelerations, which would be a fundamental change in the rate of human aging. Looking into the 21st C, 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 to favor the spread of pathogens. We anticipate continuing socio-economic disparities of life expectancy. PMID:24401556

  20. Infiltration kinetics of fibrous preform

    SciTech Connect

    Yamauchi, Toshio; Nishida, Yoshinori

    1994-12-31

    The infiltration kinetics of fibrous preform was investigated in the case of aluminum matrix composites by pressure infiltration method. Pressure was applied mechanically by a punch, and the pressure change and the punch speed were measured during the infiltration of molten aluminum into SiC whisker preforms. To analyze the correlation between applied pressure and infiltration front in the preform, the distribution of hardness along the infiltration direction in the composites was measured and the distribution of volume fraction was calculated from the hardness. A theoretical expression is derived to describe fluid flow in the preform during the infiltration, on the condition that the pressure on the preform surface starts to rise from zero and when the applied pressure exceeds the compressive strength of preform, deformation starts. The starting point of deformation and the distribution of volume fraction in the composites can be calculated by the theory and proved by experiments.

  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. 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...

  3. Reactive infiltration in fabricating silicon carbide composites for electronic packaging

    NASA Astrophysics Data System (ADS)

    Xiao, Liming

    The silicon carbide (SiC) composite is a promising material to improve thermal dissipation and thermal expansion matching for electronic packaging, but its wide application has been greatly hindered by the high fabrication cost. To address this cost issue, two new reactive infiltration methods have been proposed and developed to fabricate SiC composite in a net-shape manner. They are Method 1--locally magnesium-enhanced infiltration and Method 2--globally carbon-enhanced infiltration. In Method 1, a magnesium wetting agent was strategically inserted at the interface between SiC powder and Al-Si alloy. The molten Al-Si alloy was assisted by chemical reaction to infiltrate into the porous SiC powder in an inert atmosphere sealed in a quartz tube or a steel cup. The infiltration kinetics was characterized by measuring the infiltration weight gain with respect to time. It was found that the infiltration kinetics could be divided into three stages: infiltration initiation, rapid infiltration, and slow infiltration, and most of the weight gain occurred in the rapid infiltration stage. The rapid infiltration was due to the magnesium-silicon oxide reaction and the magnesium accumulation at the infiltration front. Modeling of the infiltration kinetics showed the magnesium dilution increased the dynamic contact angle, which in turn decreased the infiltration rate. The SiC oxidation, Mg content and temperature were shown to be important factors affecting the infiltration. In Method 2, a carbon wetting agent is coated globally on every SiC particle. To accomplish this coating, a slip casting, drying, curing and carbonization process was developed. A crucibleless infiltration method was designed to fabricate SiC composites in an open atmosphere protected by nitrogen. The temperature change of SiC preform during infiltration was monitored to determine the infiltration kinetics. The silicon-carbon reaction was found to create a spontaneous infiltration of molten Si or molten Al

  4. Groundwater Mounding Beneath Stormwater Infiltration Basins

    NASA Astrophysics Data System (ADS)

    Nimmer, M.; Thompson, A. M.; Misra, D.

    2007-12-01

    An accurate understanding of groundwater mound formation is important in the proper design of stormwater infiltration basins since these basins are often required to recharge a portion of pre-development infiltration volume. Mound formation due to localized recharge may reduce the infiltration rate of the basin and the ability of the soil to filter pollutants. The goal of this research was to understand groundwater mounding and the potential for contaminant transport resulting from recharge beneath stormwater infiltration basins. A 0.10 ha infiltration basin serving a 9.4 ha residential subdivision in Oconomowoc, Wisconsin was used in this study. Subsurface conditions included sand and gravel material and a groundwater table at 2.3 m below grade. Three storm events, 4.9 cm, 2.8 cm, and 4.3 cm, between August 2006 and April 2007 were modeled using the two-dimensional numerical model HYDRUS. The calibrated model was used to evaluate hypothetical basin operation scenarios for various basin sizes, soil types, ponding depths, and water table depths. The groundwater mound intersected the basin floor in most scenarios with loamy sand and sandy loam soils, an unsaturated thickness of 1.52 m, and a ponding depth of 0.61 m. No groundwater table response was observed with ponding depths less than 0.31 m with an unsaturated zone thickness of 6.09 m. The mound height was most sensitive to hydraulic conductivity and unsaturated zone thickness. A 7.6 cm sediment layer delayed the time to reach maximum mound height, but had a minimal effect on the magnitude of the mound. Mound heights increased as infiltration basin size increased.

  5. The influence of surface sorption and air flow rate on phthalate emissions from vinyl flooring: Measurement and modeling

    NASA Astrophysics Data System (ADS)

    Liang, Yirui; Xu, Ying

    2015-02-01

    This study investigated the influences of surface sorption and air flow rate on the emission of phthalates from building materials. Controlled tests were conducted in specially designed stainless steel and wood chambers, and the steady-state concentration in the stainless steel chamber was about 2-3 times higher than that in the wood chamber for di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP). The emission rate of phthalates increased in the wood chamber due to the diffusion mass flow through the chamber wall (i.e., surface absorption). The adsorption isotherm of phthalates on the stainless steel surface and the absorption parameters (i.e., diffusion and partition coefficients) of phthalates on the wood surface were determined experimentally, and the values were comparable to those in the literature. The equilibration time scale for phthalates absorbed to the sink reservoir in actual indoor environments was estimated and can be substantial (approximately 80 years), indicating that surface absorption may continuously drive phthalates from their indoor sources to various sinks and thus significantly increase the emission rate of phthalates. The gas-phase concentration of DEHP was measured in two stainless steel chambers operated at flow rates of 300 mL/min and 3000 mL/min, respectively, which were both adjusted to 1000 mL/min after steady state was reached. The gas-phase concentration of DEHP in the chamber was very sensitive to the chamber air flow rate, and higher air flow rates resulted in lower concentration levels. However, the increased emission rate compensated for the dilution in the gas phase and made the DEHP concentration not drop substantially with an increase in the air flow rate. Independently measured or calculated parameters were used to validate a semi-volatile organic compounds (SVOCs) emission model that included absorptive surfaces and for a range of air flow rates, with excellent agreement between the model predictions and the

  6. Liquid precursor infiltration processing of powder compacts. 1: Kinetic studies and microstructure development

    SciTech Connect

    Tu, W.C.; Lange, F.F.

    1995-12-01

    The kinetics of infiltrating a solution precursor into Si{sub 3}N{sub 4} powder compacts were studied using either water or an aqueous solution of Zr-nitrate and Y-nitrate that formed a crystalline Zr(Y)O{sub 2} (3 mol% Y{sub 2}O{sub 3}) solid solution during pyrolysis. When the powder compact contained air, the infiltration involved two steps: (1) relatively rapid intrusion of liquid via flow due to capillary pressure and (2) diffusion of entrapped gas to the surface as its pressure became equal to the capillary pressure. The kinetics of both processes are described with different parabolic rate laws--Darcy`s law and Fick`s law, respectively. When the intruded precursor is converted to an inorganic during heat treatment, the void space is partially filled with pyrolyzed precursor without shrinkage of the Si{sub 3}N{sub 4} powder. The movement of precursor molecules was prevented by gelling prior to drying, viz., by soaking the infiltrated bodies in an aqueous NH{sub 4}OH solution. Microstructures developed during cyclic precursor infiltration and pyrolysis were characterized to show that cracklike voids are produced within the pyrolyzed precursor due to its large volume change during pyrolysis and densification; the size distribution of the cracklike voids is proportional to the size distribution of the voids within the initial powder compact.

  7. Infiltration in heterogeneous soil monitored by neutron imaging

    NASA Astrophysics Data System (ADS)

    Snehota, Michal; Sobotkova, Martina; Jelinkova, Vladimira; Sacha, Jan; Vontobel, Peter; Cislerova, Milena

    2014-05-01

    The process of infiltration in near-saturated soil and fate of residual air bubbles was studied using neutron imaging. It is the continuation of previous study on flow instability. Ponding infiltration-outflow experiment conducted at NEUTRA beamline of the Spallation Neutron Source Division, Paul Scherrer Institut aimed at i) characterizing the types of structures susceptible to air trapping, ii) monitoring of entrapped air and water redistribution during steady state flow iii) imaging the process of entrapped air dissolution. Experiments were conducted on series of undisturbed samples of soil from the Cambisol series and on an artificially prepared sample. The latter was composed of coarse sand (representing pathways of fast preferential flow), which surrounded blocks of fine ceramic. Cumulative infiltration and outflow fluxes of water were measured gravimetrically by two precision digital scales thus the full water balance data were obtained. Small samples (30 mm in diameter) were used to achieve good spatial resolution of neutron images. Degassed water was used to dissolve bubbles of entrapped air at the end of infiltration experiments. The neutron radiography and tomography data show quantitatively exchange of water and air between domains of fine and coarse materials during quasi-steady state flow in the sample. The redistribution of the entrapped air directly affected the hydraulic conductivity. On neutron tomography images the gradual dissolving of trapped air bubbles was clearly detected. The effect also led to significant increase of hydraulic conductivity. The obtained data show clearly that air as a non-wetting phase should not be overlooked in case of near-saturated infiltration in soil with preferential flow. The research was supported by the Czech Science Foundation Project No. 14-03691S.

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

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Allisy-Roberts, P. J.; Selbach, H. J.

    2015-01-01

    An indirect comparison of the standards for reference air kerma rate (RAKR) for 192Ir high dose rate (HDR) brachytherapy sources of the Physikalisch-Technische Bundesanstalt (PTB), Germany, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the PTB in September 2011. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the PTB and the BIPM standards for reference air kerma rate, is 1.0003 with a combined standard uncertainty of 0.0099. 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).

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

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Downton, B.; Mainegra-Hing, E.

    2015-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate (HDR) brachytherapy sources of the National Research Council (NRC), Canada, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the NRC in August 2014. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the NRC and the BIPM standards for reference air kerma rate, is 0.9966 with a combined standard uncertainty of 0.0050. 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).

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

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Kurosawa, T.; Mikamoto, T.

    2016-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate (HDR) brachytherapy sources of the National Metrology Institute of Japan (AIST-NMIJ), Japan, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the Japan Radioisotope Association (JRIA) in April 2015. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the NMIJ and the BIPM standards for reference air kerma rate, is 1.0036 with a combined standard uncertainty of 0.0054. 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).

  11. 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...

  12. Infiltrating angiolipoma with phlebolith formation.

    PubMed

    De Orchis, D; Ozonoff, M B

    1986-01-01

    Angiolipomas are uncommon benign soft tissue tumors with both fatty and vascular components; they may be encapsulated or locally invasive. Three cases are reported in which phleboliths were present within infiltrating angiolipomas. The demonstration of phleboliths in a lipoma suggests the diagnosis of infiltrating angiolipoma rather than the usual encapsulated lipoma. PMID:3764475

  13. Inexpensive perfluorocarbon tracer technique for wide-scale infiltration measurements in homes

    SciTech Connect

    Dietz, R.N.; Cote, E.A.; Senum, G.I.; Wieser, R.F.

    1981-08-01

    A perfluorocarbon tracer technique to determine infiltration rates in homes is described. A tracer kit, coined the Brookhaven National Laboratory Air Infiltration Measurement System, which can be deployed by the average homeowner, is briefly described. The tracer source is a fluoroelastomer plug impregnated with a known mass of perfluorocarbon tracers (PFT) and crimped within a metal shell. The PFT diffuses from the end of the plug. Two samplers briefly described are: the capillary adsorption tube sampler (CATS) and the programmable Brookhaven Atmospheric Tracer Sampler (BATS). Deployment of one of the diffusion sources in a home and use of a BATS unit to measure the increase in the tracer concentration perfluorodimethylcyclohexane (PDCH) are discussed. Results of the tests are presented. (MCW)

  14. 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.

  15. 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.

  16. 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

  17. Modeling Hydrologic and Geochemical Aspects of Rapid Infiltration Basins

    NASA Astrophysics Data System (ADS)

    Akhavan, M.; Imhoff, P. T.; Andres, S.; Finsterle, S.; Gu, C.; Maggi, F.

    2010-12-01

    Land-based wastewater treatment is the controlled application of wastewater to soil to remove wastewater constituents. A Rapid Infiltration Basin (RIB) is a major land treatment technique where treated wastewater is infiltrated at high rates in shallow basins, with further treatment occurring in soil and the vadose zone before the water recharges groundwater. Because the influent wastewater is usually enriched in nitrogen compounds, there is particular concern that a RIB may contaminant groundwater or nearby surface waters if not designed and operated properly. RIBs are operated in repetitive cycles of flooding, infiltration, and drying. Key operational parameters include the ratio of wetting to drying time and the hydraulic loading rate, which affect pollutant residence time and water table rise in shallow groundwater systems. They also alter water saturation and air content in the vadose zone, which have an impact on denitrification. Optimum values of the wetting-drying cycle ratio and the hydraulic loading rate are expected to vary with the quality of applied wastewater, soil type, treatment objective, and climate. Soil development within the basins may have an important effect on RIB performance. In this study, numerical modeling is used to obtain optimum values for the wetting-drying cycle ratio and hydraulic loading rate for different soil types and environmental conditions. TOUGH2/ iTOUGH2, a general-purpose numerical simulation program for multi-phase fluid flow in porous media, is used for modeling fluid movement. Overland flow within RIBs is coupled with subsurface flow to investigate the influence of non-uniform application of wastewater on hydraulic performance. TOUGHREACT v1.1 is used for modeling nitrogen fate and transport. Flow simulations indicate that using a long flooding cycle results in more water spreading over the basin and higher vadose zone water saturations than more frequent short-duration flooding events. Results of modeling fate and

  18. Comparison of success rate of intubation through Air-Q with ILMA using two different endotracheal tubes

    PubMed Central

    Malhotra, SK; Bharath, KV; Saini, Vikas

    2016-01-01

    Background and Aims: Air-Q™ is a newly introduced airway device, which can be used to facilitate endotracheal intubation. The primary aim of this study was to assess whether use of two different endotracheal tubes (ETTs) (standard polyvinyl chloride [PVC] and reinforced PVC) increases the success rate of blind intubation through Air-Q™ (Group Q) when compared with intubating laryngeal mask airway (ILMA- Fastrach™) keeping ILMA as control (Group I). Methods: One hundred and twenty patients aged between 18 and 60 years with American Society of Anesthesiologists physical status I-II, undergoing elective surgery under general anaesthesia, were enrolled into this prospective, randomised, case–control study to compare the success rate of tracheal intubation between ILMA (Fastrach™) and Air-Q™ intubating laryngeal airway. Those patients with anticipated difficult airway were excluded from the study. All the recruited patients completed the study. Reinforced PVC ETT was used in both airway devices to secure intubation. Since standard PVC tube is recommended for use in Air-Q, when first intubation attempt failed, second or third attempt was made with standard PVC ETT. Total of three attempts were made for each procedure: Whereas in ILMA group, only reinforced tube was used in all three attempts. Results: The overall success rate after three attempts was more with Air-Q (96.6%) in our study compared with ILMA (91.6%) but no significant difference was seen between the groups (P = 0.43). Conclusion: The present study shows that when intubation with reinforced tube fails, the success rate with use of conventional PVC tube is more with Air-Q when compared with ILMA. PMID:27141106

  19. 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...

  20. 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,...

  1. 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...

  2. 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.

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

    NASA Astrophysics Data System (ADS)

    Heilweil, Victor M.; McKinney, Tim S.; Zhdanov, Michael S.; Watt, Dennis E.

    2007-07-01

    As populations grow in arid 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.

  4. Modeling Nitrogen Losses under Rapid Infiltration Basins

    NASA Astrophysics Data System (ADS)

    Akhavan, M.; Imhoff, P. T.; Andres, A. S.; Finsterle, S.

    2011-12-01

    Rapid Infiltration Basin System (RIBS) is one of the major land treatment techniques used for wastewater treatment and reuse of recovered treated wastewater. In this system, wastewater that is treated using primary, secondary, or advanced treatment techniques is applied at high rates to shallow basins constructed in permeable deposits of soil or sand, with further treatment occurring in soil and the vadose zone before the water recharges groundwater. Because the influent wastewater is usually enriched in nitrogen (N) compounds, there is particular concern that RIBS may contaminant groundwater or nearby surface waters if not designed and operated properly. In most of the new sequenced batch reactor (SBR) wastewater treatment plants, N is found in the form of nitrate in the discharged wastewater, so denitrification (DNF) is the main reaction in N removal. The absence of molecular oxygen is one of the required conditions for DNF. During RIBS operation, application of wastewater is cyclic and typically consists of a flooding period followed by days or weeks of drying. Key operational parameters include the ratio of wetting to drying time and the hydraulic loading rate, which affect water saturation and air content in the vadose zone and as a result have an impact on DNF. Wastewater is typically distributed at a limited number of discharge points in RIBS and basins are not usually completely flooded which result in non-homogeneous distribution of wastewater and unusual surface water flow patterns. For this reason, we couple overland flow within RIBS with subsurface flow to investigate the influence of non-uniform application of wastewater on DNF. No modeling effort has been done for understanding this aspect of RIBS performance previously. TOUGH2/ iTOUGH2, a general-purpose numerical simulation program for multi-phase fluid flow in porous media, is used for modeling fluid movement. Water saturation is used as a surrogate parameter to evaluate oxygen limitations in the

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

    PubMed

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

    2010-02-23

    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 (SO(2)) 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 SO(2) >200 ppb and acid aerosol (n=19); chronic exposure to SO(2) ≥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 SO(2) 100-250 ppb and concentration of respirable particles of diameter ≥2.5 μ (PM(2.5)) >500 μg/m(3). 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

  6. 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.

  7. Experimental Validation and Applications of a Fluid Infiltration Model

    PubMed Central

    Kao, Cindy S.; Hunt, James R.

    2010-01-01

    Horizontal infiltration experiments were performed to validate a plug flow model that minimizes the number of parameters that must be measured. Water and silicone oil at three different viscosities were infiltrated into glass beads, desert alluvium, and silica powder. Experiments were also performed with negative inlet heads on air-dried silica powder, and with water and oil infiltrating into initially water moist silica powder. Comparisons between the data and model were favorable in most cases, with predictions usually within 40% of the measured data. The model is extended to a line source and small areal source at the ground surface to analytically predict the shape of two-dimensional wetting fronts. Furthermore, a plug flow model for constant flux infiltration agrees well with field data and suggests that the proposed model for a constant-head boundary condition can be effectively used to predict wetting front movement at heterogeneous field sites if averaged parameter values are used. PMID:20428480

  8. Relative contributions of transient and steady state infiltration during ephemeral streamflow

    USGS Publications Warehouse

    Blasch, K.W.; Ferre, T. P. A.; Hoffmann, J.P.; Fleming, J.B.

    2006-01-01

    Simulations of infiltration during three ephemeral streamflow events in a coarse-grained alluvial channel overlying a less permeable basin-fill layer were conducted to determine the relative contribution of transient infiltration at the onset of streamflow to cumulative infiltration for the event. Water content, temperature, and piezometric measurements from 2.5-m vertical profiles within the alluvial sediments were used to constrain a variably saturated water flow and heat transport model. Simulated and measured transient infiltration rates at the onset of streamflow were about two to three orders of magnitude greater than steady state infiltration rates. The duration of simulated transient infiltration ranged from 1.8 to 20 hours, compared with steady state flow periods of 231 to 307 hours. Cumulative infiltration during the transient period represented 10 to 26% of the total cumulative infiltration, with an average contribution of approximately 18%. Cumulative infiltration error for the simulated streamflow events ranged from 9 to 25%. Cumulative infiltration error for typical streamflow events of about 8 hours in duration in is about 90%. This analysis indicates that when estimating total cumulative infiltration in coarse-grained ephemeral stream channels, consideration of the transient infiltration at the onset of streamflow will improve predictions of the total volume of infiltration that may become groundwater recharge. Copyright 2006 by the American Geophysical Union.

  9. Model description of storage and infiltration functions of infiltration facilities for urban runoff analysis by a distributed model.

    PubMed

    Furumai, H; Jinadasa, H K P K; Murakami, M; Nakajima, F; Aryal, R K

    2005-01-01

    Although there have been simulation researches focusing on reduction of stormwater peak flow by introduced infiltration facilities, model simulation of dynamic runoff behavior is still limited for frequently occurring rainfall events with weak intensity. Therefore, dynamic simulation was carried out in two urban drainages with infiltration facilities incorporated with a distributed model using two methods for describing functions of infiltration facilities. A method adjusting effective rainfall model gave poor simulation of runoff behavior in light rainfalls. Another method considering dynamic change of storage capacity as well as infiltration rate gave satisfactory estimation of the runoff in both drainages. In addition, assumption of facility clogging improved the agreement between measured and simulated hydrographs in small and medium-sized rainfall. Therefore, the proposed method might be useful for quantifying the secondary effects of the infiltration facilities on groundwater recharge and urban non-point pollutant trapping as well as runoff reduction. PMID:16248180

  10. 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

  11. 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). PMID:25246092

  12. 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.

  13. [Effects of air pollution on stillbirth rates in an industrial town].

    PubMed

    Dimitriev, D A

    2000-01-01

    The impact of seasonal variations in ambient air pollution with some compounds (suspended matters, sulphur dioxide, carbon oxide, nitrogen dioxide) on stillbirth was studied. Changes in the concentration of the studied pollutants were found to affect stillbirth. PMID:11030098

  14. 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)

  15. Impact of Blow/Fill/Seal process variables in determining rate of vial contamination by air dispersed microorganisms.

    PubMed

    Leo, Frank; Poisson, Patrick; Sinclair, Colin S; Tallentire, Alan

    2005-01-01

    Controlled challenges of air dispersed spores of Bacillus subtilis NCIMB 8649 have been generated in a custom-built challenge room housing a Blow/Fill/Seal machine filling filter-sterilized trypticase soy broth into 5.5 cm3 low density polyethylene vials. The effects on the rate of vial contamination of systematic changes in the process variables, rate of provision of ballooning air, delay in the application of mould vacuum and duration of transfer of the open vial, have been examined. Overall, the findings show that the conditions of vial formation can affect appreciably the rate of vial contamination from airborne spores. The indications are that heat lethality, associated with the elevated temperature required for polymer extrusion and vial formation, has a role in determining such contamination. PMID:16316067

  16. Water-depth dependent infiltration into burnt forest soils

    NASA Astrophysics Data System (ADS)

    Langhans, Christoph; Sheridan, Gary; Noske, Phil; Metzen, Daniel; Lane, Patrick

    2014-05-01

    Infiltration into severely burnt forest soils in South Eastern Australia exhibits a behaviour that is at odds with traditional infiltration theories that assumes a coherent soil matrix, which has important implications for upscaling from plot to hillslope. Infiltration patterns were studied at three severely burnt sites with different soils by applying a blue dye solution during rainfall and runon experiments, and subsequent profile excavation. Rainfall and runon rates were varied on each plot, runoff measured, and orthogonal photos taken during quasi-steady states. From transects on these photos average inundation fractions of the surface were measured, and 1.5 mm horizontal resolution DEMs were generated with image-based software. This information was combined in a DEM inundation algorithm that calculated water depth maps for each plot and rainfall and runon rate. At all three sites, nearly 100% of infiltration occurred through macropores that bypass the matrix of a water repellent layer. Average fractions of subsoil dye staining were 3% in shallow soils with a northerly aspect and low trees, 60% in deep soils with southerly aspects and high trees, and 20% in an intermediate soil. This was consistent with runoff coefficients of 0.94 for the shallow soil, 0.08 for the deep soil, and 0.71 for the intermediate soil. Irrespective of the runoff coefficient or dyed fraction there was a positive relationship between average water depth and infiltration rates on a given plot. Functions of water depth vs. bypass infiltration were derived inversely for each plot by matching average infiltration rates with the rates derived from sampling the water depth distributions. Additionally, characteristic bypass infiltration rates for all sites as function of runon and rainfall intensity were derived, normalized by the maximum infiltration rate at full inundation. These infiltration functions represent the water depth-dependent dynamics of runoff generation in bypass infiltration

  17. Measurement of HO{sub x}{center_dot} 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 ({center_dot}OH and HO{sub 2} {center_dot}) 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 HO{sub x}{center_dot} production rate in indoor air caused by radon decay. Average HO{sub x}{center_dot} production rate was found to be (4.31{plus_minus}0.07) {times} 10{sup 5} HO{sub x}{center_dot} per Rn decay per second (Bq) 3.4 to 55.0% at 22C. This work provided G{sub (HO{sub x}{center_dot})}-value, 7.86{plus_minus}0.13 No./100 eV in air by directly measuring [HO{sub x}{center_dot}] formed from the radiolysis procedure. This G value implies that HO{sub x}{center_dot} 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 HO{sub x}{center_dot} production rate and relative humidity. A laser-induced fluorescence (LIF) system has been used for {center_dot}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 {center_dot}OH produced from the photolysis of O{sub 3}/H{sub 2}O.

  18. 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.

  19. On the infiltration process in treated effluents spreading basins

    NASA Astrophysics Data System (ADS)

    Loewy, A.; Weisbrod, N.; Lev, O.; Lazarovitch, N.

    2009-12-01

    Secondary treated effluents originating from the Dan Region in Israel are sent to tertiary treatment that uses Soil Aquifer Treatment (SAT) for purification within the vadose zone. The SAT is based on intermittent flooding (1-2 days) and drying (2-3 days) cycles in spreading basins constructed at the surface of a 40-m deep vadose zone. The site is located in the natural sand dunes north to the city of Ashdod, above the Israeli Coastal Plain Aquifer. The study aim is to investigate the physical and chemical processes that occur within the upper 2 meters of the spreading basins’ sandy soil profiles during the cyclic SAT operation. We explored two 2-m profiles about 50 m apart. In addition to ponding depth, continuous measurements of volumetric water content (VWC), temperature, electrical conductivity (EC) and oxidation-reduction potential at 8 different depths within the first profile were recorded. Data were collected in 15-min resolution during infiltration events for 3 months. Measurements in the second profile have been collected for a few weeks now and also include air pressure measurements. Additionally, soil samples were taken from both profiles to determine hydraulic parameters. Preliminary results indicate that the infiltration rate in the first profile is about 72 cm day-1, a low rate compared to what would be expected from a sandy profile. The VWC changes along this profile during the flooding stage imply percolation in the form of a double wetting front. First, the wetting front proceeds from the surface downward until effective saturation of 0.55. Second, the wetting front proceeds from 2-m upwards until effective saturation of 0.7 is reached. We assume the presence of a local lower hydraulic conductivity layer or a local perched water table at a depth of 4-5 m (perched above a deeper low hydraulic conductivity layer). This layer may cause the observed double wetting front. This combined with approximately 30% of entrapped air within the pores may be

  20. 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. PMID:24698118

  1. Effect of ambient air pollution on daily mortality rates in Guangzhou, China

    NASA Astrophysics Data System (ADS)

    Yu, Ignatius Tak Sun; Zhang, Yong hui; San Tam, Wilson Wai; Yan, Qing Hua; Xu, Yan jun; Xun, Xiao jun; Wu, Wei; Ma, Wen Jun; Tian, Lin Wei; Tse, Lap Ah; Lao, Xiang Qian

    2012-01-01

    We aimed to investigate the effects of ambient air pollutants on daily mortality in a relatively stable and homogeneous population in Guangzhou, China. Daily mortality, air pollution, and weather data between 2006 and 2009 were collected. The generalized additive model with poison regression was used to estimate the excessive risks (ERs) of air pollutants (PM 10, SO 2, and NO 2) on total, cardiovascular and respiratory mortality. The effects of lag0-1 were the greatest for total non-accidental and cardiovascular deaths. The increments of 10 μg m -3 in SO 2, NO 2, and PM 10 were associated with ERs of 1.54% (95%CI: 1.03-2.06%), 1.42% (95%CI: 1.06-1.78%), and 1.26% (95%CI: 0.86-1.66%) respectively for total non-accidental deaths, and 2.28% (95%CI: 1.40-3.16%), 1.81% (95%CI: 1.20-2.41%), and 1.79% (95%CI: 1.11-2.47%) respectively for cardiovascular deaths. For persons who died from respiratory disease, however, the maximum effects occurred at lag0. The ERs for SO 2, NO 2, and PM 10 were 1.36% (95%CI: 0.23-2.50%), 1.47% (95%CI: 0.66-2.29%) and 0.93% (95%CI: 0.03-1.83%), respectively. The effects of the three air pollutants on mortality were stronger in elderly and in women. The ERs in the present study were higher than those reported in Europe, the U.S., and most other Asian cities. Our findings show relatively higher ERs of daily mortality by ambient air pollutants in the center of Guangzhou, China, compared with estimates in other cities. Further studies with accurate exposure measurement among homogeneous population are needed to evaluate the precise magnitudes of the effects of the air pollutants.

  2. 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.

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

    PubMed Central

    Wang, Kaicun; Zhou, Chunlüe

    2015-01-01

    Global analyses of surface mean air temperature (Tm) 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 Tm. Existing global analyses calculate Tm 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 Tm 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. PMID:26198976

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

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun; Zhou, Chunlüe

    2015-07-01

    Global analyses of surface mean air temperature (Tm) 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 Tm. Existing global analyses calculate Tm 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 Tm 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.

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

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun; Zhou, Chunlüe

    2016-04-01

    Global analyses of surface mean air temperature (Tm) 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 depends on the calculation methods of Tm. Existing global analyses calculated Tm 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 Tm 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.

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

    PubMed

    Wang, Kaicun; Zhou, Chunlüe

    2015-01-01

    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. PMID:26198976

  7. Enhanced infiltration regime for treated-wastewater purification in soil aquifer treatment (SAT)

    NASA Astrophysics Data System (ADS)

    Nadav, Itamar; Arye, Gilboa; Tarchitzky, Jorge; Chen, Yona

    2012-02-01

    SummaryUtilization of treated wastewater (TWW) for agriculture is a widely accepted practice in regions suffering from freshwater (FW) shortages. Soil aquifer treatment is often employed for wastewater purification in regions with sandy soil. Infiltration rates of water through the soil can decrease as a result organic matter (OM) accumulation and the consequential water repellency. We examined several infiltration regimes with the aim of achieving lower levels of OM accumulation, reduced water repellency and increased infiltration rate in the topsoil layer of the infiltration basin. OM accumulation in the topsoil layer was found to be the main factor adversely affecting soil permeability. In measurements performed in the infiltration basins of the Tel Aviv wastewater-purification facility over a 1-year period, infiltration rates were found to differ with season, being low in the winter and high in the summer. Similar observations were made on small model infiltration ponds established to simulate the large basins. Several water-application regimes were tested for enhancement of the infiltration rates. Rapid application of TWW was the most efficient method in terms of reducing OM accumulation and water repellency in the topsoil layer. Low-rate, and spraying of TWW over the soil using sprinklers produced the highest OM accumulation and consequently, higher water repellency. Low-rate, single outlet application—the conventional infiltration method employed in the commercial infiltration basins—exhibited moderate OM accumulation and water repellency. Neither water repellency nor OM accumulation were observed in the FW-application regime. Accumulation of OM originating from the percolating TWW, at the topsoil layer was identified as dominating infiltration rate at the infiltration basins. Reduction of OM content by the means proposed and evaluated in this experiment can drastically increase infiltration rates.

  8. 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...

  9. 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.

  10. Lower responsiveness of canopy evapotranspiration rate than of leaf stomatal conductance to open-air CO2 elevation in rice.

    PubMed

    Shimono, Hiroyuki; Nakamura, Hirofumi; Hasegawa, Toshihiro; Okada, Masumi

    2013-08-01

    An elevated atmospheric CO2 concentration ([CO2 ]) can reduce stomatal conductance of leaves for most plant species, including rice (Oryza sativa L.). However, few studies have quantified seasonal changes in the effects of elevated [CO2 ] on canopy evapotranspiration, which integrates the response of stomatal conductance of individual leaves with other responses, such as leaf area expansion, changes in leaf surface temperature, and changes in developmental stages, in field conditions. We conducted a field experiment to measure seasonal changes in stomatal conductance of the uppermost leaves and in the evapotranspiration, transpiration, and evaporation rates using a lysimeter method. The study was conducted for flooded rice under open-air CO2 elevation. Stomatal conductance decreased by 27% under elevated [CO2 ], averaged throughout the growing season, and evapotranspiration decreased by an average of 5% during the same period. The decrease in daily evapotranspiration caused by elevated [CO2 ] was more significantly correlated with air temperature and leaf area index (LAI) rather than with other parameters of solar radiation, days after transplanting, vapor-pressure deficit and FAO reference evapotranspiration. This indicates that higher air temperatures, within the range from 16 to 27 °C, and a larger LAI, within the range from 0 to 4 m(2)  m(-2) , can increase the magnitude of the decrease in evapotranspiration rate caused by elevated [CO2 ]. The crop coefficient (i.e. the evapotranspiration rate divided by the FAO reference evapotranspiration rate) was 1.24 at ambient [CO2 ] and 1.17 at elevated [CO2 ]. This study provides the first direct measurement of the effects of elevated [CO2 ] on rice canopy evapotranspiration under open-air conditions using the lysimeter method, and the results will improve future predictions of water use in rice fields. PMID:23564676

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

    PubMed

    Kulongoski, Justin T; Izbicki, John 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. PMID:18194325

  12. 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.

  13. Groundwater contamination from stormwater infiltration

    SciTech Connect

    Pitt, R.; Clark, S.; Parmer, K.

    1995-10-01

    The research summarized here was conducted during the first year of a 3-yr cooperative agreement (CR819573) to identify and control stormwater toxicants, especially those adversely affecting groundwater. The purpose of this research effort was to review the groundwater contamination literature as it relates to stormwater. Prior to urbanization groundwater is recharged by rainfall-runoff and snowmelt infiltrating through pervious surfaces including grasslands and woods. This infiltrating water is relatively uncontaminated. Urbanization, however, reduces the permeable soil surface area through which recharge by infiltration occurs. This results in much less groundwater recharge and greatly increased surface runoff. In addition the waters available for recharge carry increased quantities of pollutants. With urbanization, waters having elevated contaminant concentrations also recharge groundwater including effluent from domestic septic tanks, wastewater from percolation basins and industrial waste injection wells, infiltrating stormwater, and infiltrating water from agricultural irrigation. The areas of main concern that are covered by this paper are: the source of the pollutants, stormwater constituents having a high potential to contaminate groundwater, and the treatment necessary for stormwater.

  14. 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

  15. Delivery after Operation for Deeply Infiltrating Endometriosis.

    PubMed

    Allerstorfer, Christina; Oppelt, Peter; Enzelsberger, Simon H; Shamiyeh, Andreas; Schimetta, Wolfgang; 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

  16. Indoor air exposure to coal and wood combustion emissions associated with a high lung cancer rate in Xuan Wei, China

    SciTech Connect

    Mumford, J.L.; Chapman, R.S.; Harris, D.B.; He, X.Z.; Cac, S.R.

    1989-01-01

    Residents of Xuan Wei County in China have unusually high lung cancer mortality that cannot be attributed to tobacco use or occupational exposure. They are exposed to smoke from unvented, open pit coal or wood fires (often used for cooking and heating). The variation in lung cancer rates among communes within the county suggests that indoor combustion of smoky coal may be the prime determinant of lung cancer. To characterize the air in Xuan Wei homes, samples of the air particles and semivolatile organic compounds were collected from homes located in two communes; one commune has a high rate of lung cancer, and the other has a low rate. Samples collected in the commune where the lung cancer rate is high and where smoky coal is the predominant fuel contained high concentrations of small particles with high organic content; organic extracts of these samples were mutagenic. Samples from homes in the wood-burning commune, which has a low rate of lung cancer, consisted mostly of larger particles of lower organic content and mutagenicity. The smoky coal sample was a mouse skin carcinogen and was a more potent initiator of skin tumors in comparison to the wood or smokeless coal sample.

  17. Indoor air exposure to coal and wood combustion emissions associated with a high lung cancer rate in Xuan Wei, China

    SciTech Connect

    Mumford, J.L.; Chapman, R.S.; Harris, D.B. ); He, X.Z.; Cao, S.R.; Xian, Y.L.; Li, X.M. )

    1989-01-01

    Residents of Xuan Wei County in China have unusually high lung cancer mortality that cannot be attributed to tobacco use or occupational exposure. They are exposed to smoke from unvented, open pit coal or wood fires (often used for cooking and heating). The variation in lung cancer rates among communes within the county suggests that indoor combustion of smoky coal may be the prime determinant of lung cancer. To characterize the air in Xuan Wei homes, samples of air particles and semivolatile organic compounds were collected from homes located in two communes; one commune has a high rate of lung cancer, and the other has a low rate. Samples collected in the commune where the lung cancer rate is high and where smoky coal is the predominant fuel contained high concentrations of small particles with high organic content; organic extracts of these samples were mutagenic. Samples from homes in the wood-burning commune, which has a low rate of lung cancer, consisted mostly of larger particles of lower organic content and mutagenicity. The smoky coal sample was a mouse skin carcinogen and was a more potent initiator of skin tumors in comparison to the wood or smokeless coal sample.

  18. 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 ...

  19. Inverse Simulation of Field Infiltration Experiment Counting Preferential Flow

    NASA Astrophysics Data System (ADS)

    Zumr, David; Snehota, Michal; Nemcova, Renata; Dohnal, Michal; Cislerova, Milena

    2010-05-01

    The field tension and ponded infiltration experiments were conducted to monitor and describe irregularities of moisture propagation and to estimate the soil hydraulic properties (Distric Cambisol, Korkusova Hut, Sumava). On these soils the preferential pathways have been observed in several scales with the use of dye tracers, MRI and CT imaging. Preferential behavior was detected also during laboratory infiltration experiments. The flow irregularities are credited to variable air entrapment at the beginning of infiltrations. The field infiltration experiment was carried out in a shallow pit for a period of one day. The upper boundary condition was controlled by the tension disk infiltrometer, the propagation of a water front was monitored by two tensiometers installed in two depths below the infiltration disk. The propagation of saline solution front during ponded infiltration was visualized with high resolution electrical resistivity tomography (ERT). Infiltration experiments were monitored with TDR probes, tensiometers and ERT. Zones of preferential flow were determined through analyses of photographs taken during laboratory dye tracer infiltration experiments performed on undisturbed soil samples. Connectivity, volumetric ratio and spatial development of preferential pathways were evaluated as the necessary information for numerical simulations of flow using dual-permeability approach. 2D axisymetric numerical simulations were conducted to evaluate the results of the experiment. The parameter estimator PEST coupled with the simulation code S2D_DUAL (Vogel et al., 2000) were employed. Two different approaches were used: 1. Single-domain approach based on Richards' equation. 2. Dual-permeability approach based on two interacting water flow domains (matrix and preferential domains), each governed by one Richards' equation. Concerning the existence of preferential flow on investigated soil, the dual-permeability model gives a better picture of the flow regime. The

  20. Cave air and hydrological controls on prior calcite precipitation and stalagmite growth rates: Implications for palaeoclimate reconstructions using speleothems

    NASA Astrophysics Data System (ADS)

    Sherwin, Catherine M.; Baldini, James U. L.

    2011-07-01

    Hourly resolved cave air P and cave drip water hydrochemical data illustrate that calcite deposition on stalagmites can be modulated by prior calcite precipitation (PCP) on extremely short timescales. A very clear second-order covariation between cave air P and drip water Ca 2+ concentrations during the winter months demonstrates the effects of degassing-induced PCP on drip water chemistry. Estimating the strength of the cave air P control on PCP is possible because the PCP signal is so clear; at our drip site a one ppm shift in Ca 2+ concentrations requires a P shift of between 333 and 667 ppm. This value will undoubtedly vary from site to site, depending on drip water flow rate, residence time, drip water-cave air P differential, and availability of low P void spaces in the vadose zone above the cave. High-resolution cave environmental measurements were used to model calcite deposition on one stalagmite in Crag Cave, SW Ireland, and modelled growth over the study period (222 μm over 171 days) is extremely similar to the amount of actual calcite growth (240 μm) over the same time interval, strongly suggesting that equations used to estimate stalagmite growth rates are valid. Although cave air P appears to control drip water hydrochemistry in the winter, drip water dilution caused by rain events may have played a larger role during the summer, as evidenced by a series of sudden drops in Ca 2+ concentrations (dilution) followed by much more gradual increases in drip water Ca 2+ concentrations (slow addition of diffuse water). This research demonstrates that PCP on stalactites, cave ceilings, and void spaces within the karst above the cave partially controls drip water chemistry, and that thorough characterisation of this process at individual caves is necessary to most accurately interpret climate records from those sites.

  1. Partitioning of Infiltration into Macropore and Soil-Matrix Flow: Predictive Model Based on Mesoscale Heterogeneity of Infiltrability

    NASA Astrophysics Data System (ADS)

    Nimmo, J. R.

    2014-12-01

    A condition that initiates macropore flow at the land surface is the application of water faster than it can infiltrate into the soil matrix material. Sometimes this is taken to require ponding, but accumulated evidence shows preferential flow to be commonplace when wetness is less than saturation and when macropores are not completely filled. Examples include water flowing into shrinkage cracks or funneled into macropores by hydrophobic surface material. A more inclusive criterion is that macropore flow is generated when the water application rate exceeds the infiltrability of a small area associated with a macropore. A new model based on this criterion considers the representative elementary area (REA), as would be appropriate for measurement of field-scale infiltrability, to be divided into a mosaic of functional sub-areas (FSA). A single value of matrix infiltrability characterizes each FSA. The REA as a mosaic of FSAs is hydraulically represented by a characteristic distribution of infiltrabilities. During rainfall or irrigation, each FSA absorbs water into its soil matrix material up to the rate of its matrix infiltrability. Water applied in excess of this infiltrability is assumed to flow into a macropore within or adjacent to the FSA, becoming preferential flow. Especially if crusted or hydrophobic, an FSA can generate preferential flow even during low-intensity rainfall when other FSAs are absorbing all incident water into the matrix. The total flux of preferential flow at given depth is the sum of contributions from all FSAs. In this way the characteristic distribution of FSA infiltrabilities controls the field-scale partitioning of matrix and macropore flow as an emergent phenomenon. Illustrative case studies use field-measured data concerning water application rate and preferential flux. Results show this model can quantitatively represent observations of preferential flow occurring in relatively dry soils or at modest rainfall intensities.

  2. Modeling Water Infiltration in Soil Irrigated with Treated Wastewater

    NASA Astrophysics Data System (ADS)

    Gharaibeh, Mamoun; Albalasmeh, Ammar; Alghzawi, Ma'in

    2015-04-01

    Infiltration of soils irrigated with treated wastewater (TWW) was modeled using Philip, Horton, Kostiakov, and modified Kostiakov. Treatments were: soil irrigated with TWW for 5 years, 2 years, and a control site. Cumulative (Ft), rate of infiltration (ft), and hydraulic conductivity (HC) were measured in the field and aggregate stability (AS) in the lab. Both HC and ft were decreased with and AS was increased with TWW use and period of application. The Root Mean Squared Error (RMSE) and correlation coefficient (R2) were used to measure the goodness of fit and linearity of the relationship between models and measured data. Philip model was best to fit infiltration compared to other models. High AS values in treated areas compared to control area indicated that infiltration was more affected by pore clogging than soil dispersion and swelling,

  3. The Analysis of Ratings Using Generalizability Theory for Student Outcome Assessment. AIR 1988 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Erwin, T. Dary

    Rating scales are a typical method for evaluating a student's performance in outcomes assessment. The analysis of the quality of information from rating scales poses special measurement problems when researchers work with faculty in their development. Generalizability measurement theory offers a set of techniques for estimating errors or…

  4. Identifying Peer Institutions for Graduation Rate Comparisons. AIR 2000 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Walsh, Timothy A.

    This study used publicly available information to identify institutional controllable variables that influence graduation rate and to group colleges using these factors. The dependent variable for the correlation analysis was the six-year graduation rate of the fall 1993 freshman cohort (as reported by US News and World Report) at more than 1,400…

  5. 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 ...

  6. Simulating and explaining passive air sampling rates for semi-volatile compounds on polyurethane foam passive samplers

    PubMed Central

    Petrich, Nicholas T.; Spak, Scott N.; Carmichael, Gregory R.; Hu, Dingfei; Martinez, Andres; Hornbuckle, Keri C.

    2013-01-01

    Passive air samplers (PAS) including polyurethane foam (PUF) are widely deployed as an inexpensive and practical way to sample semi-volatile pollutants. However, concentration estimates from PAS rely on constant empirical mass transfer rates, which add unquantified uncertainties to concentrations. Here we present a method for modeling hourly sampling rates for semi-volatile compounds from hourly meteorology using first-principle chemistry, physics, and fluid dynamics, calibrated from depuration experiments. This approach quantifies and explains observed effects of meteorology on variability in compound-specific sampling rates and analyte concentrations; simulates nonlinear PUF uptake; and recovers synthetic hourly concentrations at a reference temperature. Sampling rates are evaluated for polychlorinated biphenyl congeners at a network of Harner model samplers in Chicago, Illinois during 2008, finding simulated average sampling rates within analytical uncertainty of those determined from loss of depuration compounds, and confirming quasi-linear uptake. Results indicate hourly, daily and interannual variability in sampling rates, sensitivity to temporal resolution in meteorology, and predictable volatility-based relationships between congeners. We quantify importance of each simulated process to sampling rates and mass transfer and assess uncertainty contributed by advection, molecular diffusion, volatilization, and flow regime within the PAS, finding PAS chamber temperature contributes the greatest variability to total process uncertainty (7.3%). PMID:23837599

  7. Dose rate estimates from irradiated light-water-reactor fuel assemblies in air

    SciTech Connect

    Lloyd, W.R.; Sheaffer, M.K.; Sutcliffe, W.G.

    1994-01-31

    It is generally considered that irradiated spent fuel is so radioactive (self-protecting) that it can only be moved and processed with specialized equipment and facilities. However, a small, possibly subnational, group acting in secret with no concern for the environment (other than the reduction of signatures) and willing to incur substantial but not lethal radiation doses, could obtain plutonium by stealing and processing irradiated spent fuel that has cooled for several years. In this paper, we estimate the dose rate at various distances and directions from typical pressurized-water reactor (PWR) and boiling-water reactor (BWR) spent-fuel assemblies as a function of cooling time. Our results show that the dose rate is reduced rapidly for the first ten years after exposure in the reactor, and that it is reduced by a factor of {approx}10 (from the one year dose rate) after 15 years. Even for fuel that has cooled for 15 years, a lethal dose (LD50) of 450 rem would be received at 1 m from the center of the fuel assembly after several minutes. However, moving from 1 to 5 m reduces the dose rate by over a factor of 10, and moving from 1 to 10 m reduces the dose rate by about a factor of 50. The dose rates 1 m from the top or bottom of the assembly are considerably less (about 10 and 22%, respectively) than 1 m from the center of the assembly, which is the direction of the maximum dose rate.

  8. 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

  9. 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.

  10. 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.

  11. Cooling rates of living and killed chicken and quail eggs in air and in helium-oxygen gas mixture.

    PubMed

    Tazawa, H; Turner, J S; Paganelli, C V

    1988-01-01

    1. In a helium atmosphere, heat is dissipated from a surface 3.5 times faster than it is in air. Eggs in a helium-oxygen atmosphere cool only 1.4 times faster than they cool in air. This signifies that internal resistance to heat flow is a significant factor in the cooling rates of eggs. 2. Heat flow occurs inside an egg in two ways: by conduction through the tissues and in flowing blood. Killing an embryo stops the latter, but not the former. Eggs cool more slowly after they have been killed, signifying that blood flow can be an important component in an egg's internal flows of heat. 3. Blood flow should be a relatively more important component of heat flow in large eggs than in small eggs. The difference in conductance between living and killed eggs is larger in 60 g chicken eggs than it is in 10 g quail eggs. PMID:2900113

  12. 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.

  13. 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...

  14. 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.

  15. 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. PMID:20478555

  16. Microalgae cultivation in air-lift reactors: modeling biomass yield and growth rate as a function of mixing frequency.

    PubMed

    Barbosa, Maria J; Janssen, Marcel; Ham, Nienke; Tramper, Johannes; Wijffels, René H

    2003-04-20

    The slow development of microalgal biotechnology stems from the failure in the design of large-scale photobioreactors where light energy is efficiently utilized. Due to the light gradient inside the reactor and depending on the mixing properties, algae are subjected to certain light/dark cycles where the light period is characterized by a light gradient. These light/dark cycles will determine productivity and biomass yield on light energy. Air-lift reactors can be used for microalgae cultivation and medium-frequency light/dark cycles will be found in these systems. Light/dark cycles are associated with two basic parameters: first, the light fraction, i.e., the ratio between the light period and the cycle time and second, the frequency of the light/dark cycle. In the present work, light/dark cycles found in air-lift reactors were simulated taking into account the light gradient during the light period. The effect of medium-frequency cycle time (10-100 s) and light fraction (0.1-1) on growth rate and biomass yield on light energy of the microalgae Dunaliella tertiolecta was studied. The biomass yield and growth rates were mainly affected by the light fraction, while cycle time had little influence. Response surface methodology was used and a statistical model describing the effect of light fraction and cycle time on growth rate and biomass yield on light energy was developed. The use of the model as a reactor design criterion is discussed. PMID:12584758

  17. 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.

  18. Ni-coated SiC{sub p} reinforced aluminum composites processed by vacuum infiltration

    SciTech Connect

    Chung, W.S.; Lin, S.J.

    1996-12-01

    A vacuum infiltration process has been developed to process aluminum-base composites reinforced with particulate SiC{sub p}. Electroless nickel coating of SiC{sub p} was used to improve wetting by molten aluminum. Experimental results showed that composites of aluminum with 5.9 wt % Si and 0.23 wt % Mg containing about 50 vol % Ni-coated SiC{sub p} were completely infiltrated at a temperature above 700 C. The effects of nickel coating thickness and infiltration temperature on infiltration behavior were investigated. The infiltration rate increased and the infiltration incubation time decreased with increasing infiltration temperature or nickel coating thickness. The microstructure, nickel distribution, bending strength and fracture were also examined. Nonuniformity bending strength and fracture morphology were attributed to nickel macrosegregation.

  19. Radial water infiltration advance evaporation processes during irrigation using point source emitters in rigid and swelling soils

    NASA Astrophysics Data System (ADS)

    Su, Ninghu

    2007-10-01

    SummaryIn this paper we investigate the dynamic water balance of radial flows during irrigation using point source emitters. The components of radial flows of this kind include infiltration simultaneously coupled to the storage and advance on the soil surface, and evaporation into the air while the source continuously supplies water. The soils we consider here can be rigid or swelling. Because the infiltration equations reported for both rigid and swelling soils have an identical mathematical structure, the analysis for rigid soils using Philip's two-term infiltration equation applies to both swelling and rigid soils. As such, we emphasise that our analysis is applicable to both rigid and swelling soils. We first extend the radial Lewis-Milne equation (RLME) given by Rasmussen to analyse the radial flow mechanics by incorporating evaporation as a key component in the radial dynamic water balance. Then we present a set of four solutions of the RLME using Philip's two-parameter infiltration equation and two-term and three-term equations for cumulative evaporation. With the two-term cumulative evaporation equation, we show that the three solutions yield a simple identical asymptotic formulae at large times, which can be used to design the area to be irrigated, or to derive the final infiltration rate, A, and the final evaporation rate, E2. Analyses show that evaporation plays an important role in the radial dynamic water balance at large times, and as expected it plays a minor role during the early stage of irrigation (small time solutions).

  20. 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.

  1. Safety in the Chemical Laboratory: Laboratory Air Quality: Part II. Measurements of Ventilation Rates.

    ERIC Educational Resources Information Center

    Butcher, Samuel S.; And Others

    1985-01-01

    Part I of this paper (SE 538 295) described a simple model for estimating laboratory concentrations of gas phase pollutants. In this part, the measurement of ventilation rates and applications of the model are discussed. The model can provide a useful starting point in planning for safer instructional laboratories. (JN)

  2. 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...

  3. Transient soil surface sealing and infiltration model for bare soil under droplet impact

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The marked reduction in infiltration rate caused by formation of a soil surface seal due to water droplet impact on bare soil is a well known phenomenon but is rarely considered in infiltration models, especially under center pivot irrigation. Water application rates under center pivot irrigation c...

  4. Infiltration on sloping surfaces: Laboratory experimental evidence and implications for infiltration modeling

    NASA Astrophysics Data System (ADS)

    Morbidelli, Renato; Saltalippi, Carla; Flammini, Alessia; Cifrodelli, Marco; Corradini, Corrado; Govindaraju, Rao S.

    2015-04-01

    Infiltration on sloping surfaces occupies an important role in our understanding of surface and subsurface hydrology. Previous studies have provided conflicting results about the role of slope on infiltration. Here, our main objective is to highlight, by well-controlled experiments, the slope role in the absence of the conflicting contributions generated by other physical processes observed in previous studies under natural or laboratory conditions. The experimental program was designed to resolve some of the confounding factors such as lower impermeable boundary condition, range of rainfall rates relative to soil saturated hydraulic conductivity, surface sealing, and erosion of top soil. The experimental apparatus consists of a box containing a natural bare soil with slope angle γ chosen between 0° and 10°, two sensors of surface and deep flow, one probe for moisture content and an artificial rainfall generator. The primary experimental results suggest that under steady conditions and rainfall rate, r, greater than saturated hydraulic conductivity, Ks, the deep flow, Qd, decreases with increasing slope angle, γ, up to a value leading to Qd(γ = 1°)/Qd(γ = 10°) equal to ≈4 which is in contrast with the results provided in a few earlier papers. Furthermore, in sloping bare soils surface runoff is produced even for r < Ks. Finally, we discuss the link between Qd(γ) and the shear stress at the soil surface as a guideline in the determination of an effective saturated hydraulic conductivity to be incorporated in the existing horizontal infiltration models.

  5. Effect of the Entrapped air on Water Flow in Heterogeneous Soil: Experimental Set- up

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    Temporal variations of steady state water flow rates were observed in laboratory infiltration experiments done on a sample of compacted sand and on an undisturbed soil sample (Eutric Cambisol). These variations are found to be in relation with entrapped air content. Infiltration-outflow experiments consisted of a series of ponded infiltration runs with seepage face boundary condition at the lower end of columns. The amount of the entrapped was derived from continuous weighing of the sample. The initial water contents were different for each run, which led to different amount of the air trapped in the soil during the first stages of infiltrations. The results of the experiments done on undisturbed soil showed that the flux rates and water contents varied during quasi-steady state. This finding contradicts the standard theory. The fluctuations of the water content during the steady state flow can be ascribed to the variations in volume of the entrapped air. Similarly, shape of the bromide breakthrough curve, which were performed simultaneously during the quasi-steady state varied for undisturbed soil. The same behaviour was not observed in the sample of homogeneous sand. Computer tomography was used to characterize the structure of the undisturbed soil sample with focus on potential preferential flow pathways, which are likely to host the entrapped air. To formulate more general conclusions, an extended series of infiltration outflow and bromide breakthrough experiments is in progress. This research has been supported by research project GACR 103/08/1552 and MSMT CEZ MSM 6840770002.

  6. Numerical analysis of reaction-diffusion effects on species mixing rates in turbulent premixed methane-air combustion

    SciTech Connect

    Richardson, E.S.; Grout, R.W.; Chen, J.H.; Sankaran, R.

    2010-03-15

    The scalar mixing time scale, a key quantity in many turbulent combustion models, is investigated for reactive scalars in premixed combustion. Direct numerical simulations (DNS) of three-dimensional, turbulent Bunsen flames with reduced methane-air chemistry have been analyzed in the thin reaction zones regime. Previous conclusions from single step chemistry DNS studies are confirmed regarding the role of dilatation and turbulence-chemistry interactions on the progress variable dissipation rate. Compared to the progress variable, the mixing rates of intermediate species is found to be several times greater. The variation of species mixing rates are explained with reference to the structure of one-dimensional premixed laminar flames. According to this analysis, mixing rates are governed by the strong gradients which are imposed by flamelet structures at high Damkoehler numbers. This suggests a modeling approach to estimate the mixing rate of individual species which can be applied, for example, in transported probability density function simulations. Flame-turbulence interactions which modify the flamelet based representation are analyzed. (author)

  7. Corrosion product identification and relative rates of corrosion of candidate metals in an irradiated air-steam environment

    SciTech Connect

    Reed, D.T.; Swayambunathan, V.; Tani, B.S. ); Van Konynenburg, R.A. )

    1989-11-03

    Previously reported work by others indicates that dicopper trihydroxide nitrate, Cu{sub 2}NO{sub 3}(OH){sub 3}, forms on copper and copper alloys subjected to irradiated moist air near room temperature. We have performed experiments over a range of temperature and humidity, and have found that this species is formed at temperatures up to at least 150{degree}C if low to intermediate relative humidities are present. At 150{degree}C and 100% relative humidity, only Cu{sub 2}O and CuO were observed. The relative general corrosion rates of the copper materials tested in 1-month experiments at dose rates of 0.7 and 2.0 kGy/h were Cu > 70/30 Cu--Ni > Al-bronze. High-nickel alloy 825 showed no observable corrosion. 29 refs., 4 tabs.

  8. 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 ground-water 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

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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...

  14. 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...

  15. RAPID INFILTRATION WASTEWATER TREATMENT FOR SMALL COMMUNITIES

    EPA Science Inventory

    Rapid infiltration treatment performance of three infiltration basins receiving primary treated municipal wastewater is evaluated for optimum total nitrogen control using a series of manual operational techniques and by remote control computer operation of a sprinkler system. Thr...

  16. 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.

  17. 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.

  18. Characterization of liquid metal infiltration of a chopped fiber preform aided by external pressure. 2: Modeling of liquid metal infiltration process

    SciTech Connect

    Long, S.; Zhang, Z.; Flower, H.M.

    1995-09-01

    Based on the visualized flow behavior of Al10SiMg alloy melt in Saffil chopped fiber preforms, unidirectional infiltration of a chopped fiber preform aided by squeeze pressure has been analyzed. The relationships between melt flow and process parameters have been statistically established by the hydrodynamic analysis. The stress distribution, the variation of saturation degree and the formation of cavities due to air entrapment in the preform during infiltration have been discussed together with the analysis results.

  19. Air leakage in residential solar heating systems

    NASA Astrophysics Data System (ADS)

    Shingleton, J. G.; Cassel, D. E.; Overton, R. L.

    1981-02-01

    A series of computer simulations was performed to evaluate the effects of component air leakage on system thermal performance for a typical residential solar heating system, located in Madison, Wisconsin. Auxiliary energy required to supplement solar energy for space heating was determined using the TRNSYS computer program, for a range of air leakage rates at the solar collector and pebble bed storage unit. The effects of heat transfer and mass transfer between the solar equipment room and the heated building were investigated. The effect of reduced air infiltration into the building due to pressurized by the solar air heating system were determined. A simple method of estimating the effect of collector array air leakage on system thermal performance was evaluated, using the f CHART method.

  20. Improvement Accuracy of Assessment of Total Equivalent Dose Rate during Air Travel

    NASA Astrophysics Data System (ADS)

    Dorenskiy, Sergey; Minligareev, Vladimir

    For radiation safety on the classic flight altitudes 8-11 km is necessary to develop a methodology for calculating the total equivalent dose rate (EDR) to prevent excess exposure of passengers and crews of airliners. During development it became necessary to assess all components affecting the calculation of EDR Comprehensive analysis of the solution to this problem, based on the developed program basis, allowing to automate calculations , as well as on the assessment of the statistical data is introduced. The results have shown that: 1) Limiting accuracy of error of geomagnetic cutoff rigidity (GCR) in the period from 2005 to 2010 was 5% This error is not significant within the considered problems. 2) It is necessary to take into account seasonal variations of atmospheric parameters in the calculation of the EDR. The difference in the determination of dose rate can reach 31% Diurnal variations of atmospheric parameters are offered to consider to improve reliability of EDR estimates. 3) Introduction in the GCR calculations of additional parameters is necessary for reliability improvement and estimation accuracy of EDR on flight routs (Kp index of geomagnetic activity , etc.).

  1. 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)

  2. 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

  3. Residential infiltration of fine and ultrafine particles in Edmonton

    NASA Astrophysics Data System (ADS)

    Kearney, Jill; Wallace, Lance; MacNeill, Morgan; Héroux, Marie-Eve; Kindzierski, Warren; Wheeler, Amanda

    2014-09-01

    air cleaner was associated with reduced UFP infiltration factors in summer, suggesting a potential method of reducing infiltrated UFPs. Various cooking activities and smoking were associated with the non-ambient component of indoor FP and UFP concentrations. On average, the majority of indoor FPs were of ambient origin while the majority of UFPs were of indoor origin. In summer, more of the indoor FP and UFP concentrations were from ambient origin, compared to winter, due to the higher infiltration factors. The variability in FP and UFP Finf within and between homes may cause substantial exposure misclassification in epidemiological studies using only ambient measurements.

  4. 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.

  5. 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.

  6. 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. PMID:24951121

  7. 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.

  8. Characteristic of flotation deinking using bio and synthetic surfactant at different air flow rate

    NASA Astrophysics Data System (ADS)

    Trismawati, Wardana, I. N. G.; Hamidi, Nurkholis; Sasongko, Mega Nur

    2016-03-01

    Flotation deinking has industrially applied but several problems keep unsolved because limitations have to compete with several variables present. Flotation deinking is multi variables process, so studying flotation deinking is still interesting. In this research, the amount of variables was reduced and focused to the performance comparison between flotation deinking of old newspaper (ONP) using biodegradable fatty acid of morinda citrifolia as the raw bio surfactant (RBS) and biodegradable fatty acid of palm oil that had been converted to be commercial surfactant (CS). The flotation was done at laboratory flotation cell equipped with orifice at different diameter (orifice number 20, 40 and 60) with adjustable airflow rate. Brightness and Effective Residual Ink Concentration (ERIC) of the deinked pulp were measured. The best results were achieved on orifice number 40 with the highest brightness of 41.96 °ISO and 40.96 °ISO when using CS and RBS respectively, and lowest ERIC of 896.82 ppm and 1001.72 ppm when using CS and RBS respectively. The percentage delta of deinking power characteristic between CS and RBS was 2.36% and 11.70% for brightness and ERIC, respectively.

  9. 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. PMID:25689218

  10. 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

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

    SciTech Connect

    Wayne Hill

    2004-10-01

    The project's overall objective is to develop a commercially viable sensing system to infer the flow rate and fineness of pulverized coal flows using the dynamic signature from a pipe-mounted accelerometer. The preliminary calibration data for this effort will be obtained using a Coal Flow Test Facility built and operated by our subcontractor, Airflow Sciences Corporation, in support of an EPRI program. Airflow Sciences encountered significant difficulty getting the system up and running, with the final hurdles related to the system controls. These problems were resolved in this reporting period, so that the facility is ready for testing. Shakedown testing with our instrumentation package began late in the reporting period. Preliminary analysis of the resulting data indicates that there are problems with the instrumentation and/or test rig. Even with no flow passing through the test section, a power spectrum of the data shows strong frequency ''lines''. The data should be free of such behaviors, so the instrumentation must be recording behaviors that are unrelated to the flow. This issue must be resolved before calibration data are collected. A preliminary effort to debug the problem through long-distance consultation between Foster-Miller and Airflow Sciences personnel at the end of the reporting period did not discover the source of the problem. Consequently, a Foster-Miller engineer will visit the test facility early in the next reporting period. Assuming this effort is successful, preliminary testing and analysis should be completed in the next reporting period. Because of slack in the program schedule, there should be no net effect on the program scope, cost, or schedule.

  12. A pilot study to determine medical laser generated air contaminant emission rates for a simulated surgical procedure.

    PubMed

    Lippert, Julia F; Lacey, Steven E; Lopez, Ramon; Franke, John; Conroy, Lorraine; Breskey, John; Esmen, Nurtan; Liu, Li

    2014-01-01

    The U.S. Occupational Safety and Health Administration (OSHA) estimates that half a million health-care workers are exposed to laser surgical smoke each year. The purpose of this study was to establish a methodology to (1) estimate emission rates of laser-generated air contaminants (LGACs) using an emission chamber, and to (2) perform a screening study to differentiate the effects of three laser operational parameters. An emission chamber was designed, fabricated, and assessed for performance to estimate the emission rates of gases and particles associated with LGACs during a simulated surgical procedure. Two medical lasers (Holmium Yttrium Aluminum Garnet [Ho:YAG] and carbon dioxide [CO2]) were set to a range of plausible medical laser operational parameters in a simulated surgery to pyrolyze porcine skin generating plume in the emission chamber. Power, pulse repetition frequency (PRF), and beam diameter were evaluated to determine the effect of each operational parameter on emission rate using a fractional factorial design. The plume was sampled for particulate matter and seven gas phase combustion byproduct contaminants (benzene, ethylbenzene, toluene, formaldehyde, hydrogen cyanide, carbon dioxide, and carbon monoxide): the gas phase emission results are presented here. Most of the measured concentrations of gas phase contaminants were below their limit of detection (LOD), but detectable measurements enabled us to determine laser operation parameter influence on CO2 emissions. Confined to the experimental conditions of this screening study, results indicated that beam diameter was statistically significantly influential and power was marginally statistically significant to emission rates of CO2 when using the Ho:YAG laser but not with the carbon dioxide laser; PRF was not influential vis-a-vis emission rates of these gas phase contaminants. PMID:24498966

  13. 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 ...

  14. Polyacrylamide molecular weight effects on soil infiltration and erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seal formation at the surface of smectitic soils during rainstorms reduces soil infiltration rate (IR) and causes runoff and erosion. Surface application of dry anionic polyacrylamide (PAM) with high molecular weight (MW) has been found to be effective in stabilizing soil aggregates, and decreasing ...

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

    SciTech Connect

    Chuang, J.; Cao, S.; Xian, Y.; Harris, B.; Mumford, J.

    1992-01-01

    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 micrometers) 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.

  16. 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.

  17. Critical effect of pore characteristics on capillary infiltration in mesoporous films.

    PubMed

    Ceratti, D R; Faustini, M; Sinturel, C; Vayer, M; Dahirel, V; Jardat, M; Grosso, D

    2015-03-12

    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. PMID:25723817

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Influence of specimen size, tray inclination and air flow rate on the emission of gases from biomass combustion

    NASA Astrophysics Data System (ADS)

    Amorim, E. B.; Carvalho, J. A.; Soares Neto, T. G.; Anselmo, E.; Saito, V. O.; Dias, F. F.; Santos, J. C.

    2013-08-01

    Experiments of biomass combustion were performed to determine whether specimen size, tray inclination, or combustion air flow rate was the factor that most affects the emission of carbon dioxide, carbon monoxide, and methane. The chosen biomass was Eucalyptus citriodora, a very abundant species in Brazil, utilized in many industrial applications, including combustion for energy generation. Analyses by gas chromatograph and specific online instruments were used to determine the concentrations of the main emitted gases, and the following figures were found for the emission factors: 1400 ± 101 g kg-1 of CO2, 50 ± 13 g kg-1 of CO, and 3.2 ± 0.5 g kg-1 of CH4, which agree with values published in the literature for biomass from the Amazon rainforest. Statistical analysis of the experiments determined that specimen size most significantly affected the emission of gases, especially CO2 and CO.

  3. Infiltrative lung diseases in pregnancy.

    PubMed

    Freymond, N; Cottin, V; Cordier, J F

    2011-03-01

    Pregnancy may affect the diagnosis, management, and outcome of infiltrative lung disease (ILD). Conversely, ILD may affect pregnancy. ILD may occur as a result of drugs administered commonly or specifically during pregnancy. Most ILDs predominate in patients older than 40 years and are thus rare in pregnant women. During pregnancy ILD may arise de novo and preexisting ILD may be exacerbated or significantly worsened. Some ILDs generally do not alter the management of pregnancy, labor, or delivery. Preexisting ILD no longer contraindicates pregnancy systematically, but thorough evaluation of ILD before pregnancy is required to identify potential contraindications and adapt monitoring. PMID:21277455

  4. Heart Rate and Heart Rate Variability Assessment Identifies Individual Differences in Fear Response Magnitudes to Earthquake, Free Fall, and Air Puff in Mice

    PubMed Central

    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. PMID:24667366

  5. 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.

  6. Determining air pollutant emission rates based on mass balance using airborne measurement data over the Alberta oil sands operations

    NASA Astrophysics Data System (ADS)

    Gordon, M.; Li, S.-M.; Staebler, R.; Darlington, A.; Hayden, K.; O'Brien, J.; Wolde, M.

    2015-09-01

    Top-down approaches to measure total integrated emissions provide verification of bottom-up, temporally resolved, inventory-based estimations. Aircraft-based measurements of air pollutants from sources in the Canadian oil sands were made in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring during a summer intensive field campaign between 13 August and 7 September 2013. The measurements contribute to knowledge needed in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring. This paper describes the top-down emission rate retrieval algorithm (TERRA) to determine facility emissions of pollutants, using SO2 and CH4 as examples, based on the aircraft measurements. In this algorithm, the flight path around a facility at multiple heights is mapped to a two-dimensional vertical screen surrounding the facility. The total transport of SO2 and CH4 through this screen is calculated using aircraft wind measurements, and facility emissions are then calculated based on the divergence theorem with estimations of box-top losses, horizontal and vertical turbulent fluxes, surface deposition, and apparent losses due to air densification and chemical reaction. Example calculations for two separate flights are presented. During an upset condition of SO2 emissions on one day, these calculations are within 5 % of the industry-reported, bottom-up measurements. During a return to normal operating conditions, the SO2 emissions are within 11 % of industry-reported, bottom-up measurements. CH4 emissions calculated with the algorithm are relatively constant within the range of uncertainties. Uncertainty of the emission rates is estimated as less than 30 %, which is primarily due to the unknown SO2 and CH4 mixing ratios near the surface below the lowest flight level.

  7. 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.

  8. 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.

  9. Enhancement of T cell recruitment and infiltration into tumours

    PubMed Central

    Oelkrug, C; Ramage, J M

    2014-01-01

    Studies have documented that cancer patients with tumours which are highly infiltrated with cytotoxic T lymphocytes show enhanced survival rates. The ultimate goal of cancer immunotherapy is to elicit high-avidity tumour-specific T cells to migrate and kill malignant tumours. Novel antibody therapies such as ipilumimab (a cytotoxic T lymphocyte antigen-4 blocking antibody) show enhanced T cell infiltration into the tumour tissue and increased survival. More conventional therapies such as chemotherapy or anti-angiogenic therapy and recent therapies with oncolytic viruses have been shown to alter the tumour microenvironment and thereby lead to enhanced T cell infiltration. Understanding the mechanisms involved in the migration of high-avidity tumour-specific T cells into tumours will support and provide solutions for the optimization of therapeutic options in cancer immunotherapy. PMID:24828133

  10. Delays in hiring Air Traffic Collegiate Training Initiative (AT-CTI) graduates and the impact on their training success rate

    NASA Astrophysics Data System (ADS)

    Jorgenson, Terra A.

    arrive at the FAA Academy. In addition, the effect of the wait on the success rate of training at the FAA Academy and at the candidate's first facility was examined. Data was collected to examine the relationship between a CTI graduate's performance in the CTI program and the individual's performance during FAA training at the FAA Academy and assignment to their first facility. Through correlation analysis of the Air Traffic Basics (AT-Basic), Air Traffic Selection and Training (AT-SAT) and Performance Verification (PV) scores there was significant correlation between the AT-Basic and PV scores. As the AT-Basic score increases so does the PV scores. There needs to be future research on GPA's, PV's, AT-SAT and AT-Basics scores to determine if any of them are predictors of CTI's success in training. If the FAA can better predict if an applicant will be successful in training, it can save the FAA money in the selection, hiring and training process.

  11. Free-air CO{sub 2} enrichment effects on rate and duration of apical development of spring wheat

    SciTech Connect

    Li, Ai-Guo; Trent, A.; Wall, G.W.; Kimball, B.A.

    1997-05-01

    Rates and durations of individual phases of wheat (Triticum aestivum L.) apical development are among the most important factors that determine yield components. Because atmospheric CO{sub 2} has been increasing steadily, it is important to evaluate the effects of elevated CO{sub 2} on wheat development. This study was conducted to determine rates and durations of leaf, spikelet, and floret primordium initiation in a Free-Air Carbon Dioxide Enrichment (FACE) system. Spring wheat (cv. Yecora Roja) was planted at the University of Arizona Maricopa Agricultural Center. The two CO{sub 2} concentrations were 550 (elevated) and 370 (ambient) {mu}mol mol{sup -1} CO{sub 2}. Individual plant samples were collected every 3 to 4 d. We dissected the main stem (MS), coleoptile tiller (T0), primary tillers (T1, T2, and T3) and secondary tillers (T00, T01, T02, T10, T11, and T12) and counted primordia. Apex primordium data were fitted to a four-piece linear-spline segmented regression model with the SAS proc NLIN. No influence of elevated CO{sub 2} (550 {mu}mol mol{sup -1}) on leaf primordium initiation of MS was detected. Nevertheless, CO{sub 2} enrichment significantly increased was detected. Nevertheless, CO{sub 2} enrichment significantly increased rates of spikelet primordium initiation of MS, T1, T2, T10, and T11, and diminished the durations of spikelet development phase of MS, T1, T2, T3, T10, and T11. Within the floret phase, CO{sub 2} enrichment significantly increased rates of floret primordium initiation of MS, floret primordium initiation of MS, T0, T1, T3, and T11. The information from this study will be utilized to predict wheat apical development and grain production in the elevated atmospheric CO{sub 2} environments of the future. 40 refs., 4 figs., 5 tabs.

  12. Connecting bacterial colonization to physical and biochemical changes in a sand box infiltration experiment

    NASA Astrophysics Data System (ADS)

    Rubol, S.; Freixa, A.; Carles-Brangarí, A.; Fernàndez-Garcia, D.; Romaní, A. M.; Sanchez-Vila, X.

    2014-09-01

    Infiltration through sediments is linked to complex biogeochemical processes occurring at small spatial scales, often leading to a progressive reduction in infiltration rates due to microbial growth and/or mechanical clogging. Unraveling the linkage between microbial dynamics and water infiltration in a heterogeneous medium is of concern in artificial recharge ponds and natural infiltration systems. We present an 84-day laboratory infiltration experiment that aims at studying the temporal variation of selected biogeochemical parameters at different depths along the infiltration path. The experimental setup consists of a 1.2 m high tank packed with a heterogeneous soil and instrumented with arrays of sensors as well as soil and liquid samplers. Results indicate that: (i) microbial processes are responsible for infiltration reduction, enhancing the spatially heterogeneous distribution of infiltration rates with time, (ii) bacteria and extracellular polymeric substances (EPS) are present at all monitored depths, indicating the potential for deep biological clogging, (iii) bacteria functioning and richness exhibit depth zonation after the system reaches a mature state and (iv) the retention curve changes towards highest saturation by the end of the experiment. The increase in water holding capacity is largest at depth, where the presence of EPS is noticeable. The reduction in time of the quantity of water infiltrating along the tank can only be accounted for with a truly interdisciplinary approach involving physical, chemical and biological processes.

  13. 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

  14. 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.

  15. 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

  16. An experiment of rainfall infiltration under different boundary conditions

    NASA Astrophysics Data System (ADS)

    Hao, Shuang; Tong, Fuguo; Xue, Song

    2016-04-01

    Rainfall infiltration is a two-phase flow of water and gas, which should be simulated through solving the nonlinear governing equations of gas and water flow. In order to avoid the three main problems, such as convergence, numerical stability and computational efficiency in the solution of the nonlinear governing equations, Richard equation was usually used to simulate rainfall infiltration when the effect of gas phase could be ignored. The purpose of this work is to study the effect of boundary condition on rainfall infiltration, and to know in which cases Richard equation is available for the simulation of rainfall infiltration. The sample of soil has a height of 1200 mm. It is tightly enclosed in a toughened glass sleeve. The gas pressure is equal to the atmospheric pressure on the top surface of the model. The gas tight of its bottom can be controlled by a tap to simulate two different gas boundary conditions, permeable boundary and impermeable boundary. When the bottom of the model is not gas tight, the water infiltration rate is entirely bigger than gas tight. There is a big difference over the long time of rainfall that infiltration rate tends to be stable to 0.05cm/min when permeable but it is only 0.002cm/min when impermeable. The dramatic contrast reflects that gas paly a hindered part during rainfall infiltration. In addition, the gas pressure is obviously lower when the model is not gas tight. Although the pore gas pressure rise a little bit when water block gas, it is still same with atmospheric pressure all time. The situation is different when gas tight, the pore gas pressure increases sharply in the early stage and stable to a higher value, such as 10cm gas pressure on 67cm depth. Therefore, people basically negate the correlation between gas pressure and rainfall infiltration rate, but the evidence points out that the effect of gas pressure is in a significant position and Richard equations are not accurate under gas impermeable condition.

  17. 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.

  18. Effect of spatial variability of soil properties on infiltration

    NASA Astrophysics Data System (ADS)

    Domenech, Marisa; Castro Franco, Mauricio; Aparicio, Virginia; Costa, José Luis

    2013-04-01

    Topography and soil properties are key determinants of spatial variability of water content. Prediction of soil hydraulic properties are essential for modeling water flow and solute transport. In the southeastern of Buenos Aires Province, the effect of the relief on soil spatial variability is result of the relationship between elevation and effective depth (ED). Digital elevation models (DEM) provide quantitive information about relief. The objective was to determine the effect of spatial variability of soil properties on infiltration. The field was 50 ha and the soil classes were vertic Hapludoll, typic and petrocalcic Argiudoll. ED was measured using Gidding_Soil_Sampler® in 30x30m grid size. Elevation data were measured ussing a DGPS Trimble_R3®. From this, a DEM was generated. Two elevation and ED areas were delineated named High and Low zones. Three soil samples were taken at each zone with three replications at depth 0-30 and 30-90 cm. Texture, bulk density (δb) and organic matter (OM) were determined. A disc infiltrometer was used to determine the water infiltration rate (i). Clay content (As) and OM were homogeneous in the profile of the High zone. However, As content at 30-90 cm decreased in the Low zone. At the High zone, δb ranged from 1.31 to 1.34 g cm-3 and was higher than at the Low zone (δb=1.16 - 1.27 g cm-3). Also the i had less variation at the High zone. Under pressure head of -1 cm , the i increased in the Low zone. At lower pressure heads, the i was greater in the High zone. Higher i at the Low zone could be due to major ED, textural heterogeneity and higher OM content. Textural homogeneity, shallow ED and high δb allowed a more stable i at the High zone. Using topography and ED is a promising way of characterizing soil hydraulic behavior and its spatial variability across a field.

  19. 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

  20. Light propagation mechanism switching in a liquid crystal infiltrated microstructured polymer optical fibre

    NASA Astrophysics Data System (ADS)

    Rutkowska, K. A.; Milenko, K.; Chojnowska, O.; Dąbrowski, R.; Woliński, T. R.

    2015-12-01

    In this work studies on propagation properties of a microstructured polymer optical fibre infiltrated with a nematic liquid crystal are presented. Specifically, the influence of an infiltration method on the LC molecular alignment inside fibre air-channels and, thus, on light guidance is discussed. Switching between propagation mechanisms, namely the transition from modified total internal reflection (mTIR) to the photonic bandgap effect obtained by varying external temperature is also demonstrated.

  1. Infiltration of reaction-bonded silicon nitride with equilibrium Y-Si-O-N melt

    SciTech Connect

    Sheu, T.S. . Dept. of Biologic and Materials Science)

    1994-02-01

    An equilibrium Y-Si-O-N melt was infiltrated to eliminate the open porosity of reaction-bonded silicon nitride at 1600--1800 C. This oxynitride melt contained two equilibrium phases, a [beta]-Si[sub 3]N[sub 4] solid phase and a liquid phase at high temperatures. Before infiltration, porous reaction-bonded silicon nitride compacts were heat-treated to completely transform to the [beta]-Si[sub 3]N[sub 4] phase. After infiltration, the flexural strength of the reaction-bonded silicon nitride material increased from 200 to 600 MPa at 25 C, from 200 to 300 MPa at 1400 C in air.

  2. 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.

  3. Ambient particulate air pollution, heart rate variability, and blood markers of inflammation in a panel of elderly subjects.

    PubMed Central

    Pope, C Arden; Hansen, Matthew L; Long, Russell W; Nielsen, Karen R; Eatough, Norman L; Wilson, William E; Eatough, Delbert J

    2004-01-01

    Epidemiologic studies report associations between particulate air pollution and cardiopulmonary morbidity and mortality. Although the underlying pathophysiologic mechanisms remain unclear, it has been hypothesized that altered autonomic function and pulmonary/systemic inflammation may play a role. In this study we explored the effects of air pollution on autonomic function measured by changes in heart rate variability (HRV) and blood markers of inflammation in a panel of 88 elderly subjects from three communities along the Wasatch Front in Utah. Subjects participated in multiple sessions of 24-hr ambulatory electrocardiographic monitoring and blood tests. Regression analysis was used to evaluate associations between fine particulate matter [aerodynamic diameter less than or equal to 2.5 microm (PM2.5)] and HRV, C-reactive protein (CRP), blood cell counts, and whole blood viscosity. A 100- microg/m3 increase in PM2.5 was associated with approximately a 35 (SE = 8)-msec decline in standard deviation of all normal R-R intervals (SDNN, a measure of overall HRV); a 42 (SE = 11)-msec decline in square root of the mean of the squared differences between adjacent normal R-R intervals (r-MSSD, an estimate of short-term components of HRV); and a 0.81 (SE = 0.17)-mg/dL increase in CRP. The PM2.5-HRV associations were reasonably consistent and statistically robust, but the CRP association dropped to 0.19 (SE = 0.10) after excluding the most influential subject. PM2.5 was not significantly associated with white or red blood cell counts, platelets, or whole-blood viscosity. Most short-term variability in temporal deviations of HRV and CRP was not explained by PM2.5; however, the small statistically significant associations that were observed suggest that exposure to PM2.5 may be one of multiple factors that influence HRV and CRP. PMID:14998750

  4. 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

  5. Modeling air pollutant emissions from Indian auto-rickshaws: Model development and implications for fleet emission rate estimates

    NASA Astrophysics Data System (ADS)

    Grieshop, Andrew P.; Boland, Daniel; Reynolds, Conor C. O.; Gouge, Brian; Apte, Joshua S.; Rogak, Steven N.; Kandlikar, Milind

    2012-04-01

    Chassis dynamometer tests were conducted on 40 Indian auto-rickshaws with 3 different fuel-engine combinations operating on the Indian Drive Cycle (IDC). Second-by-second (1 Hz) data were collected and used to develop velocity-acceleration look-up table models for fuel consumption and emissions of CO2, CO, total hydrocarbons (THC), oxides of nitrogen (NOx) and fine particulate matter (PM2.5) for each fuel-engine combination. Models were constructed based on group-average vehicle activity and emissions data in order to represent the performance of a 'typical' vehicle. The models accurately estimated full-cycle emissions for most species, though pollutants with more variable emission rates (e.g., PM2.5) were associated with larger errors. Vehicle emissions data showed large variability for single vehicles ('intra-vehicle variability') and within the test group ('inter-vehicle variability'), complicating the development of a single model to represent a vehicle population. To evaluate the impact of this variability, sensitivity analyses were conducted using vehicle activity data other than the IDC as model input. Inter-vehicle variability dominated the uncertainty in vehicle emission modeling. 'Leave-one-out' analyses indicated that the model outputs were relatively insensitive to the specific sample of vehicles and that the vehicle samples were likely a reasonable representation of the Delhi fleet. Intra-vehicle variability in emissions was also substantial, though had a relatively minor impact on model performance. The models were used to assess whether the IDC, used for emission factor development in India, accurately represents emissions from on-road driving. Modeling based on Global Positioning System (GPS) activity data from real-world auto-rickshaws suggests that, relative to on-road vehicles in Delhi, the IDC systematically under-estimates fuel use and emissions; real-word auto-rickshaws consume 15% more fuel and emit 49% more THC and 16% more PM2.5. The models

  6. Influence of air flow rate on emission of DEHP from vinyl flooring in the emission cell FLEC: Measurements and CFD simulation

    NASA Astrophysics Data System (ADS)

    Clausen, Per Axel; Liu, Zhe; Xu, Ying; Kofoed-Sørensen, Vivi; Little, John C.

    2010-07-01

    The emission of di-(2-ethylhexyl)phthalate (DEHP) from one type of vinyl flooring with ˜15% (w/w) DEHP as plasticizer was measured at 22 °C in five FLECs + one blank FLEC (Field and Laboratory Emission Cell). Initially, the flow through all FLECs was 450 ml min -1. After 689 days the flows were changed to 1000 ml min -1, 1600 ml min -1, 2300 ml min -1, and 3000 ml min -1, respectively, in four FLECs, and kept at 450 ml min -1 in one FLEC. Air samples were collected from the effluent air at regular intervals. After 1190 days the experiments were terminated and the interior surfaces of all six FLECs were rinsed with methanol to estimate the internal surface concentrations of DEHP. The DEHP air concentration and specific emission rate (SER) at steady state was estimated for the five different flow rates. The steady-state concentrations decreased slightly with increasing air flow with only the two highest flow rates resulting in significantly lower concentrations. In contrast, the SERs increased significantly. Despite large variation, the internal surface concentrations appeared to decrease slightly with increasing FLEC flow. Computational fluid dynamic (CFD) simulations suggest that the interior gas and surface concentrations were roughly uniform for the low flow case (450 ml min -1), under which, the partitioning between the FLEC internal surface and chamber air was examined. Although paired t-tests showed no difference between CFD and experimental results for DEHP air concentrations and SERs at steady-state conditions, CFD indicated that the experimental DEHP surface concentrations in the FLECs were underestimated. In conclusion, the experiments showed that the emission of DEHP from vinyl flooring is subject to "external" control and that the SER is strongly and positively dependent on the air exchange rate. However, the increased SER almost compensates for the decrease in gas-phase concentration caused by the increased air exchange.

  7. 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.

  8. 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

  9. Infiltration in soils with a saturated surface

    NASA Astrophysics Data System (ADS)

    Hogarth, W. L.; Lockington, D. A.; Barry, D. A.; Parlange, M. B.; Haverkamp, R.; Parlange, J.-Y.

    2013-05-01

    An earlier infiltration equation relied on curve fitting of infiltration data for the determination of one of the parameters, which limits its usefulness in practice. This handicap is removed here, and the parameter is now evaluated by linking it directly to soil-water properties. The new predictions of infiltration using this evaluation are quite accurate. Positions and shapes of soil-water profiles are also examined in detail and found to be predicted analytically with great precision.

  10. 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

  11. 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.

  12. 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. PMID:26246583

  13. 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

  14. The Significance of Bronchoalveolar Lavage Fluid Cytology in Diagnosing Lung Infiltrates in Children

    PubMed Central

    Selimovic, Amina; Mujicic, Ermina; Milisic, Selma; Pejicic, Tanja; Rancic, Milan; Mesihovic-Dinarevic, Senka; Lukic-Bilela, Lada; Moro, Mahir

    2016-01-01

    Aim: The aim of this research is to show why is it important in diagnosing children with lung infiltrates. Methods: Our study included 50 children with lung infiltrates during period 2005-2012, and was conducted on Pediatric Clinic of the University Clinical Center Sarajevo. We sent all cytological BAL analyses to the University Clinical Center Sarajevo. Cytology was performed by direct microscopy. BAL cytology was performed by the principle of sending samples for centrifuging, 12000 revolutions during a 10 min Shandon-cyto spin. Then the centrifuged sample is dried in the air during 1-2 hours, and is then dyed under the May-Grünwald-Giemsa staining, and analyzed under the Olympus BX41 microscope. Results: Nosocomial pneumonia has occurred in 32% children, acquired pneumonia in 38%, and 30% children had a lung infiltrates. 6 (12%) of children were younger then 1 year old, 23 (46%) children were between 1 to 5 years, 14 (28%) of children were between 5 to 10 ages, and 7 (14%) of children were between 10-15 ages. The most of the changes in observed children took place on the right lung, 34%, while 26% occurred on the left side, 22% were normal and 18% changes have affected both lungs, right and left. Percentage of cells in cytological smear in children with BAL were: cylindrical cells 28%, lung macrophage 26%, lymphocytes 17%, detritus 17% and phlegm 12%. Erythrocyte sedimentation rate (ESR) in children with BAL was up to 10-52%, to 50-30%, while ESR after first hour was above 50-18 %. Conclusion: Clinical parameters and local inflammation of the affected lobe are associated with positive bronchoalveolar cytology lavage findings. PMID:26980927

  15. Mobilization and transport of naturally occurring enterococci in beach sands subject to transient infiltration of seawater.

    PubMed

    Russell, Todd L; Yamahara, Kevan M; Boehm, Alexandria B

    2012-06-01

    This study explores the transport of enterococci (ENT) from naturally contaminated beach sands to the groundwater table via infiltrating seawater using field, laboratory, and modeling experiments. ENT were readily mobilized and transported through the unsaturated zone during infiltration events in both the field and laboratory column experiments. Detachment mechanisms were investigated using a modified version of HYDRUS-1D. Three models for detachment kinetics were tested. Detachment kinetics that are first order with respect to the rate of change in the water content and attached surface bacterial concentrations were found to provide a best fit between predicted and observed data. From these experimental and model results we conclude that detachment mechanisms associated with the rapid increases in pore water content such as air-water interface scouring and thin film expansion are likely drivers of ENT mobilization in the investigated system. These findings suggest that through-beach transport of ENT may be an important pathway through which ENT from beach sands are transported to beach groundwater where they may be discharged to coastal waters via submarine groundwater discharge. PMID:22533299

  16. Analytical determination of transition time between transient and steady state water infiltration

    NASA Astrophysics Data System (ADS)

    Lassabatere, Laurent; Angulo-Jaramillo, Rafael; di Prima, Simone; Bagarello, Vincenzo; Iovino, Massimo

    2016-04-01

    The hydraulic characterization of soil hydraulic properties is a prerequisite to the modelling of flow in the vadose zone. Since many years, numerous methods were developed to determine soil hydraulic properties. Many of these methods rely on water infiltration experiments and their analysis using analytical or numerical models. At the beginning, most models were developed for water infiltration at steady state. These models had the advantage to be easy to develop from a theoretical point of view. Yet, many drawbacks remain including the need to wait for a long time, leading to time-consuming experiments, the risk to infiltrate water in large volumes of soil, leading to a response affected by soil variability, and the uncertainty regarding the attainment of steady state (i.e. constant infiltration rate). More recently, infiltration models and mathematical developments addressed the case of consecutive transient and steady states. Yet, one main problem remain. In the field, the operator is never sure about the state of water infiltration data. This paper present analytical formulations for the estimation of a transition time. We consider the model developed by Haverkamp et al. (1994) linking 1D infiltration flux to cumulative infiltration and related approximated expansions. An analytical method based on scaling is proposed to define transition time values in terms of both scaled cumulative infiltration and times. Dimensional times are then calculated for a large variety of soils and initial conditions. These time database can be considered as a relevant tool for the guidance for operators who conduct water infiltration experiments and wants to know when to stop and also for modelers who want to know how to select the data to fit transient or steady state models. Haverkamp, R., Ross, P. J., Smetten, K. R. J., Parlange, J. Y. (1994), Three-dimensional analysis of infiltration from the disc infiltrometer: 2 Physically based infiltration equation. Water Resour. Res

  17. What is the role of wind pumping on heat and mass transfer rates at the air-snow interface?

    NASA Astrophysics Data System (ADS)

    Helgason, W.; Pomeroy, J. W.

    2010-12-01

    Accurate prediction of the turbulent exchange of sensible heat and water vapour between the atmosphere and snowpack remains a challenging task under all but the most ideal conditions. Heat and mass transfer coefficients that recognize the unique properties of the snow surface are warranted. A particular area requiring improvement concerns the role of the porous nature of snow which provides a large surface area for heat and mass exchange with the atmosphere. Wind-pumping has long been considered as a viable mechanism for incorporating aerosols into snowpacks; however these processes are not considered in parameterization schemes for heat and mass transfer near the surface. This study attempts to determine the degree to which wind pumping can increase the rates of heat and mass transfer to snow, and to ascertain which structural properties of the snowpack are needed for inclusion in heat and mass transfer coefficients that reflect wind pumping processes. Based upon a review of recent geophysical and engineering literature where porous surfaces are exploited for their ability to augment heat and mass transfer rates, a technical analysis was conducted. Numerous conceptual mechanisms of wind pumping were considered: topographically-induced flow; barometric pressure changes; high frequency pressure fluctuations at the surface; and steady flow in the interfacial region. A sensitivity analysis was performed, subjecting each conceptual model to varying thermal and hydraulic conditions at the air-snow interface, as well as variable micro-structural properties of snow. It is shown that the rate of heat and mass exchange is most sensitive to the interfacial thermal conditions and factors controlling the energy balance of the uppermost snow grains. The effect upon the thermal regime of the snowpack was found to be most significant for mechanisms of wind pumping that result in shorter flow paths near the surface, rather than those caused by low frequency pressure changes. In

  18. Rate-ratio asymptotic analysis of methane-air diffusion-flame structure for predicting production of oxides of nitrogen

    SciTech Connect

    Hewson, J.C.; Williams, F.A.

    1999-05-01

    Production rates of oxides of nitrogen in laminar methane-air diffusion flames are addressed, with thermal, prompt, and nitrous oxide mechanisms taken into account, as well as consumption processes collectively termed reburn. For this purpose, it is necessary to extend the well-known four-step flame-chemistry description to six steps, with acetylene taken out of steady-state and one-step production of nitric oxide included. Emission indices are calculated as functions of the rate of scalar dissipation at the stoichiometric mixture fraction for near-atmospheric pressures and shown to be in reasonable agreement with results obtained from numerical integrations. The various mechanisms of NO{sub x} production and consumption are verified to be strongly dependent on the flame temperature and on superequilibrium concentrations of radicals, both fuel-derived and from hydrogen-oxygen chemistry; the flame-structure analysis was extended to provide sufficient accuracy in the prediction of these quantities. It was found that for flames in near-normal ambient atmospheres, the prompt mechanism usually is most important. For longer residence times, and especially for ambient pressures and temperatures above standard, the thermal mechanism was found to increase in importance, but this increase was calculated to be offset almost entirely by NO consumption through reburn reactions. Conditions that favor reburn were observed to be those where the ratio of radical concentrations to NO concentrations is small. Longer residence times and higher pressures were demonstrated to lead both to more complete heat release and to smaller superequilibrium radical concentrations whence the correspondence between thermal production and reburn. The nitrous oxide mechanism was found to be generally less important for the conditions considered here.

  19. Measured Infiltration and Ventilation in Manufactured Homes : Residential Construction Demonstration Project, Cycle II.

    SciTech Connect

    Palmiter, Larry S.; Ecotope, Inc.

    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.

  20. Dispersion engineering in nonlinear soft glass photonic crystal fibers infiltrated with liquids.

    PubMed

    Pniewski, Jacek; Stefaniuk, Tomasz; Van, Hieu Le; Long, Van Cao; Van, Lanh Chu; Kasztelanic, Rafał; Stępniewski, Grzegorz; Ramaniuk, Aleksandr; Trippenbach, Marek; Buczyński, Ryszard

    2016-07-01

    We present a numerical study of the dispersion characteristic modification of nonlinear photonic crystal fibers infiltrated with liquids. A photonic crystal fiber based on the soft glass PBG-08, infiltrated with 17 different organic solvents, is proposed. The glass has a light transmission window in the visible-mid-IR range of 0.4-5 μm and has a higher refractive index than fused silica, which provides high contrast between the fiber structure and the liquids. A fiber with air holes is designed and then developed in the stack-and-draw process. Analyzing SEM images of the real fiber, we calculate numerically the refractive index, effective mode area, and dispersion of the fundamental mode for the case when the air holes are filled with liquids. The influence of the liquids on the fiber properties is discussed. Numerical simulations of supercontinuum generation for the fiber with air holes only and infiltrated with toluene are presented. PMID:27409187

  1. 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

  2. Reactive-infiltration instability in radial geometry

    NASA Astrophysics Data System (ADS)

    Grodzki, Piotr; Szymczak, Piotr

    2015-04-01

    A planar dissolution front propagating through a homogeneous porous matrix is unstable with respect to small variations in local permeability; regions of high permeability dissolve faster because of enhanced transport of reactants, which leads to increased rippling of the front. This phenomenon, usually referred to known as reactive-infiltration instability is an important mechanism for pattern development in geology, with a range of morphologies and scales, from cave systems running for hundreds of miles to laboratory acidization on the scale of centimeters. In general, this instability is characterized by two length scales: the diffusive length (D/v) and the reactant penetration length (v/r), where v is the Darcy velocity, D - the diffusion constant and r - the dissolution rate. If the latter scale is much smaller than the former one can adopt the so-called thin front limit, where the interface is treated as a discontinuity in porosity, with a completely dissolved phase on one side and an undissolved phase on the other. Linear stability analysis for this case has been carried out by Chadam et al. [1], and the corresponding dispersion relation shows that long wavelengths are unstable, whereas short wavelengths are stabilized by diffusion. In their derivation, Chadam et al. have considered a linear geometry with a uniform pressure gradient applied along one of the directions. However, in many cases (e.g. in the acidization techniques used in oil industry) the reactive fluids are injected through a well and thus the relevant geometry is radial rather than linear. Motivated by this, we have carried out the linear stability analysis of the reactive-infiltration problem in radial geometry, with the fluid injection at the centre of the system. We stay within the thin-front limit and derive the corresponding dispersion relation, which shows the stable regions for both the long-wavelength and short-wavelength modes, and the unstable region in between. Next, we study how

  3. 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

  4. A Study of Soil Infiltration in Northern California Almond Orchards Using a Sprinkling Infiltrometer

    NASA Astrophysics Data System (ADS)

    Brown, D. L.; Martini, C. J.

    2005-12-01

    Dormant season (winter) orchard sprays are of major concern as a source of nonpoint source (NPS) pollution. Modeling and analysis of NPS pollution is heavily constrained in the Sacramento River Valley by a near total lack of soil infiltration characteristics. Field infiltration trials are being conducted at six test sites with varying surface runoff generation potential. A Cornell sprinkling infiltrometer with a 24.1-cm diameter metal ring was used to characterize infiltration rates, runoff rates, sorptivity, and field-saturated infiltrability. This study also tested a method for simulating wet season soil conditions by saturating the ground surface before testing. A comparison with upcoming wet season infiltration measurements will be used to evaluate the validity of this method. Within one of the orchard rows tested, the field-saturated infiltration rates ranged from 0.13 to 0.26 mm/min, with a mean of 0.19 mm/min. At the same locations after seven days of drying, infiltration rates increased to 0.32 to 0.68 mm/min, with a mean of 0.49 mm/min. The field data collected will be coupled with a GIS model to create a surface runoff potential index during the winter rainy season when dormant season pesticides are applied.

  5. 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.

  6. 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%. PMID:24701379

  7. 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.

  8. Microwave assisted chemical vapor infiltration

    SciTech Connect

    Devlin, D.J.

    1993-12-31

    The purpose of this program is to develop a new process for the fabrication of ceramic matrix composites by chemical vapor infiltration. This period has been devoted in part to the exploration of material systems suitable for MACVI processing. A number of potential processing schemes are possible using combinations of absorbing and transparent material as composite components. This includes the use of an absorbing preform (nicalon fiber) combined with a transparent matrix (silicon nitride). Composites 5 cm in diameter by 1 cm. thick have been fabricated to densities of 65% theoretical. Processing times for these materials are under 20 hours. Higher densities will require additional microwave power now possible with the new reactor. The most effective MACVI scheme will involve the use of a transparent fiber with an absorbing matrix. The hot spot will be initiated by appropriate treatment of the central region of the preform. To this end alumna fibers with pretreatments to control thermal gradients has been explored. Nextel 610 fibers have been effectively pretreated carbon coating resulting in preferential heating in the interior of the preform. Possible matrix materials include siliconized silicon carbide, doped silicon carbide, alumna and zirconia. A patent for MACVI has been issued 10/19/93.

  9. 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.

  10. Groundwater Infiltration Path of Road Deicing Agent and its Quantification

    NASA Astrophysics Data System (ADS)

    Moroizumi, T.; Hada, J.; Sasaki, K.

    2015-12-01

    A deicing agent has been sprinkled on an expressway to prevent it from freezing in the hilly and mountainous area along the expressway having been used for more than 30 years. We investigated the infiltration, the river runoff, and the scattering of the de-icing agent quantitatively, observed the variation of water quality in river, and discussed the infiltration route and balance of the deicing agent in order to clarify the influence of the de-icing agent on the groundwater salinization. As a result, it turned out that 65% of the de-icing agent sprinkled on the road surface flowed into the waterway, the 25% infiltrated into underground through the crack of a road surface, and the remaining 10% dispersed out of an expressway. Next, for the rate of the de-icing agent outflowing to the river during a frozen snow term, it was estimated that the 39% of the sprinkled de-icing agent outflowed with surface water, and the 17% did with groundwater. Moreover, it was shown clearly that the 44% was probably stored in underground from the balance between the sprinkled de-icing agent and the outflowing one. In addition, the Cl- concentration of groundwater by the infiltrated deicing agent was simulated to clarify its extent and to predict its change in future when stopped sprinkling the deicing agent.

  11. QUALITY ASSURANCE PROCEDURES: METHOD 28A MEASUREMENT OF AIR TO FUEL RATIO AND MINIMUM BURN RATE FOR WOOD-FIRED APPLIANCES

    EPA Science Inventory

    Quality assurance procedures are contained in this comprehensive document intended to be used as an aid for wood heater manufacturers and testing laboratories in performing measurement of air-to-fuel ratio and minimum burn rate determinations according to EPA protocol, Method 28A...

  12. 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. PMID:19468951

  13. Association of Heart Rate Variability in Taxi Drivers with Marked Changes in Particulate Air Pollution in Beijing in 2008

    PubMed Central

    Wu, Shaowei; Deng, Furong; Niu, Jie; Huang, Qinsheng; Liu, Youcheng; Guo, Xinbiao

    2010-01-01

    Background Heart rate variability (HRV), a marker of cardiac autonomic function, has been associated with particulate matter (PM) air pollution, especially in older patients and those with cardiovascular diseases. However, the effect of PM exposure on cardiac autonomic function in young, healthy adults has received less attention. Objectives We evaluated the relationship between exposure to traffic-related PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5) and HRV in a highly exposed panel of taxi drivers. Methods Continuous measurements of personal exposure to PM2.5 and ambulatory electrocardiogram monitoring were conducted on 11 young healthy taxi drivers for a 12-hr work shift during their work time (0900–2100 hr) before, during, and after the Beijing 2008 Olympic Games. Mixed-effects regression models were used to estimate associations between PM2.5 exposure and percent changes in 5-min HRV indices after combining data from the three time periods and controlling for potentially confounding variables. Results Personal exposures of taxi drivers to PM2.5 changed markedly across the three time periods. The standard deviation of normal-to-normal (SDNN) intervals decreased by 2.2% [95% confidence interval (CI), −3.8% to −0.6%] with an interquartile range (IQR; 69.5 μg/m3) increase in the 30-min PM2.5 moving average, whereas the low-frequency and high-frequency powers decreased by 4.2% (95% CI, −9.0% to 0.8%) and 6.2% (95% CI, −10.7% to −1.5%), respectively, in association with an IQR increase in the 2-hr PM2.5 moving average. Conclusions Marked changes in traffic-related PM2.5 exposure were associated with altered cardiac autonomic function in young healthy adults. PMID:20056565

  14. Enhanced immunohistochemical detection of neural infiltration in primary melanoma: is there a clinical value?

    PubMed

    Scanlon, Patrick; Tian, Jaiying; Zhong, Judy; Silva, Ines; Shapiro, Richard; Pavlick, Anna; Berman, Russell; Osman, Iman; Darvishian, Farbod

    2014-08-01

    Neural infiltration in primary melanoma is a histopathologic feature that has been associated with desmoplastic histopathologic subtype and local recurrence in the literature. We tested the hypothesis that improved detection and characterization of neural infiltration into peritumoral or intratumoral location and perineural or intraneural involvement could have a prognostic relevance. We studied 128 primary melanoma cases prospectively accrued and followed at New York University using immunohistochemical detection with antihuman neurofilament protein and routine histology with hematoxylin and eosin. Neural infiltration, defined as the presence of tumor cells involving or immediately surrounding nerve foci, was identified and characterized using both detection methods. Neural infiltration rate of detection was enhanced by immunohistochemistry for neurofilament in matched-pair design (47% by immunohistochemistry versus 25% by routine histology). Immunohistochemical detection of neural infiltration was significantly associated with ulceration (P = .021), desmoplastic and acral lentiginous histologic subtype (P = .008), and head/neck/hands/feet tumor location (P = .037). Routinely detected neural infiltration was significantly associated with local recurrence (P = .010). Immunohistochemistry detected more intratumoral neural infiltration cases compared with routine histology (30% versus 3%, respectively). Peritumoral and intratumoral nerve location had no impact on clinical outcomes. Using a multivariate model controlling for stage, neither routinely detected neural infiltration nor enhanced immunohistochemical characterization of neural infiltration was significantly associated with disease-free or overall survival. Our data demonstrate that routinely detected neural infiltration is associated with local recurrence in all histologic subtypes but that improved detection and characterization of neural infiltration with immunohistochemistry in primary melanoma does not

  15. Melt infiltration of silicon carbide compacts. I - Study of infiltration dynamics

    NASA Technical Reports Server (NTRS)

    Asthana, Rajiv; Rohatgi, Pradeep K.

    1992-01-01

    Countergravity, pressure-assisted infiltration with a 2014 Al alloy of suitably tamped porous compacts of platelet shaped single crystals of alpha (hexagonal) silicon carbide was used to measure particulate wettability and infiltration kinetics under dynamic conditions relevant to pressure casting of composites. A threshold pressure P(th) for ingression of the infiltrant was identified based on the experimental penetration length versus pressure profiles for a range of experimental variables which included infiltration pressure, infiltration time, SiC size and SiC surface chemistry. The results showed that P(th) decreased whereas the penetration length increased with increasing SiC size and infiltration time. Cu-coated SiC led to lower P(th) and larger penetration lengths compared to uncoated SiC under identical conditions. These observations have been discussed in the light of theoretical models of infiltration and the kinetics of wetting.

  16. 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

  17. 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. PMID:27019937

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

    PubMed Central

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Chin, Jo-Yu; Parker, Edith; Breen, Michael; Brakefield, Wilma; Robins, Thomas; Lewis, Toby

    2012-01-01

    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 measurements in several seasons averaged 0.73 ± 0.76 h−1 (median = 0.57 h−1, n = 263) in the general living area, and much higher, 1.66 ± 1.50 h−1 (median = 1.23 h−1, n = 253) in bedrooms. Living area ACRs were highest in winter and lowest in spring; bedroom ACRs were highest in summer and lowest in spring. Bedrooms received an average of 55 ± 18% of air from elsewhere in the house; the living area received only 26 ± 20% from the bedroom. Interzonal flows did not depend on season, indoor smoking or the presence of air conditioners. A two-zone IAQ model calibrated for the field study showed large differences in pollutant levels between the living area and bedroom, and the key parameters affecting IAQ were emission rates, emission source locations, air filter use, ACRs, interzonal flows, outdoor concentrations, and PM penetration factors. The single-zone models that are commonly used for residences have substantial limitations and may inadequately represent pollutant concentrations and exposures in bedrooms and potentially other environments other where people spend a substantial fraction of time. PMID:23235286

  19. Infiltration and soil erosion modelling on Lausatian post mine sites

    NASA Astrophysics Data System (ADS)

    Kunth, Franziska; Schmidt, Jürgen

    2013-04-01

    Land management of reclaimed lignite mine sites requires long-term and safe structuring of recultivation areas. Erosion by water leads to explicit soil losses, especially on heavily endangered water repellent and non-vegetated soil surfaces. Beyond that, weathering of pyrite-containing lignite burden dumps causes sulfuric acid-formation, and hence the acidification of groundwater, seepage water and surface waters. Pyrite containing sediment is detached by precipitation and transported into worked-out open cuts by draining runoff. In addition to ground water influence, erosion processes are therefore involved in acidification of surface waters. A model-based approach for the conservation of man-made slopes of post mining sites is the objective of this ongoing study. The study shall be completed by modeling of the effectiveness of different mine site recultivation scenarios. Erosion risks on man-made slopes in recultivation areas should be determined by applying the physical, raster- and event based computer model EROSION 2D/3D (Schmidt, 1991, 1992; v. Werner, 1995). The widely used erosion model is able to predict runoff as well as detachment, transport and deposition of sediments. Lignite burden dumps contain hydrophobic substances that cover soil particles. Consequently, these soils show strong water repellency, which influences the processes of infiltration and soil erosion on non-vegetated, coal containing dump soils. The influence of water repellency had to be implemented into EROSION 2D/3D. Required input data for soil erosion modelling (e.g. physical soil parameters, infiltration rates, calibration factors, etc.) were gained by soil sampling and rainfall experiments on non-vegetated as well as recultivated reclaimed mine sites in the Lusatia lignite mining region (southeast of Berlin, Germany). The measured infiltration rates on the non-vegetated water repellent sites were extremely low. Therefore, a newly developed water repellency-factor was applied to

  20. Chemical vapor infiltration of carbon fiber bundles

    SciTech Connect

    Currier, R.P.; Devlin, D.J.; Barbero, R.S.

    1992-12-31

    Chemical vapor infiltration in carbon fiber bundles is studied under isothermal conditions over the temperature range 1000--1090 C at a nominal pressure of 300 Torr. Pyrolytic decomposition of methane is used in the infiltration experiments with carbon weight gain data obtained continuously from thermogravimetric analysis. The sensitivity of the infiltration dynamics to initial yarn porosity and to spatial variations in fiber positioning are explored. Results indicate that small changes in initial porosity can have significant impact on the weight gain above the solid phase percolation threshold.

  1. Chemical vapor infiltration of carbon fiber bundles

    SciTech Connect

    Currier, R.P.; Devlin, D.J.; Barbero, R.S.

    1992-01-01

    Chemical vapor infiltration in carbon fiber bundles is studied under isothermal conditions over the temperature range 1000--1090 C at a nominal pressure of 300 Torr. Pyrolytic decomposition of methane is used in the infiltration experiments with carbon weight gain data obtained continuously from thermogravimetric analysis. The sensitivity of the infiltration dynamics to initial yarn porosity and to spatial variations in fiber positioning are explored. Results indicate that small changes in initial porosity can have significant impact on the weight gain above the solid phase percolation threshold.

  2. Water and entrapped air redistribution in heterogeneous sand sample: Quantitative neutron imaging of the process

    NASA Astrophysics Data System (ADS)

    Snehota, Michal; Jelinkova, Vladimira; Sobotkova, Martina; Sacha, Jan; Vontobel, Peter; Hovind, Jan

    2015-02-01

    Saturated flow in soil with the occurrence of preferential flow often exhibits temporal changes of saturated hydraulic conductivity even during the time scale of a single infiltration event. These effects, observed in a number of experiments done mainly on heterogeneous soils, are often attributed to the changing distribution of water and air in the sample. We have measured the variation of the flow rates during the steady state stage of the constant head ponded infiltration experiment conducted on a packed sample composed of three different grades of sand. The experiment was monitored by quantitative neutron imaging, which provided information about the spatial distribution of water in the sample. Measurements were taken during (i) the initial stages of infiltration by neutron radiography and (ii) during the steady state flow by neutron tomography. A gradual decrease of the hydraulic conductivity has been observed during the first 4 h of the infiltration event. A series of neutron tomography images taken during the quasi-steady state stage showed the trapping of air bubbles in coarser sand. Furthermore, the water content in the coarse sand decreased even more while the water content in the embedded fine sand blocks gradually increased. The experimental results support the hypothesis that the effect of the gradual hydraulic conductivity decrease is caused by entrapped air redistribution and the build up of bubbles in preferential pathways. The trapped air thus restricts the preferential flow pathways and causes lower hydraulic conductivity.

  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. 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.

  5. 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.

  6. Infiltration formulas by curve number procedure.

    USGS Publications Warehouse

    Chen, C.-L.

    1982-01-01

    The Soil Conservation Service (SCS) curve number procedure for estimating runoff volume is examined in terms of the validity and applicability of the derived infiltration equations. -from ASCE Publications Abstracts

  7. 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.

  8. 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.

  9. 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...

  10. Interactions between landscape types and infiltration fluxes

    NASA Astrophysics Data System (ADS)

    Kurinova, N.

    2014-12-01

    Type of landscape is a complex characteristic include several factors which has strong influence on volume of infiltration flux. These factors are geomorphogy characteristics, soil type of vadozone, deep of ground water level, type of plants and meteorological conditions. This research are presented results of simulating water movement in one-dimensional variably saturated media for different types of landscape nearby Zvenigorod town (Moscow Region, Russia) in reserve part of Moscow River Valley. There was taking into account 11 different type of landscape. On basis of this 11 model were simulated. Examined models shown the high influence of plants type and ground water levels on infiltration recharge. The most high infiltration recharge was received for second fluvial terrace with forest, sandy soil and ground water level at 10 m deep. For a flood plain was receive the lowest value of infiltration recharge and the highest value of evaporation.

  11. Stormwater infiltration trenches: a conceptual modelling approach.

    PubMed

    Freni, Gabriele; Mannina, Giorgio; Viviani, Gaspare

    2009-01-01

    In recent years, limitations linked to traditional urban drainage schemes have been pointed out and new approaches are developing introducing more natural methods for retaining and/or disposing of stormwater. These mitigation measures are generally called Best Management Practices or Sustainable Urban Drainage System and they include practices such as infiltration and storage tanks in order to reduce the peak flow and retain part of the polluting components. The introduction of such practices in urban drainage systems entails an upgrade of existing modelling frameworks in order to evaluate their efficiency in mitigating the impact of urban drainage systems on receiving water bodies. While storage tank modelling approaches are quite well documented in literature, some gaps are still present about infiltration facilities mainly dependent on the complexity of the involved physical processes. In this study, a simplified conceptual modelling approach for the simulation of the infiltration trenches is presented. The model enables to assess the performance of infiltration trenches. The main goal is to develop a model that can be employed for the assessment of the mitigation efficiency of infiltration trenches in an integrated urban drainage context. Particular care was given to the simulation of infiltration structures considering the performance reduction due to clogging phenomena. The proposed model has been compared with other simplified modelling approaches and with a physically based model adopted as benchmark. The model performed better compared to other approaches considering both unclogged facilities and the effect of clogging. On the basis of a long-term simulation of six years of rain data, the performance and the effectiveness of an infiltration trench measure are assessed. The study confirmed the important role played by the clogging phenomenon on such infiltration structures. PMID:19587416

  12. 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

  13. 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.

  14. [Predictors of bacterial excretion in patients with infiltrative pulmonary tuberculosis].

    PubMed

    Volchegorskiĭ, I A; Novoselov, P N; Bolotov, A A

    2009-01-01

    An association of bacterial excretion with the magnitude of the X-ray and clinical symptoms of infiltrative pulmonary tuberculosis, with the intensity of concomitant anxiety-depression disorders and the results of complex laboratory peripheral blood tests was studied in 100 patients with this condition. The fact that M. tuberculosis was present in the sputum was shown to be linked to the significant increase in the size of tuberculous infiltrates, the extent of decay in the latter, their connection with the root of the lung, the spread of excretion foci, and the intensity of cough and bloody expectoration. The similar trend was demonstrated in the degree of situational anxiety, depressive indecision, and pessimism, as well as in the values of leukocytosis and erythrocyte sedimentation rate. The predictive informative value of a set of findings is illustrated by the discriminant function equation that allows the correct prediction of bacterial excretion in 76.8% of cases. PMID:20095373

  15. 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

  16. Rapid-infiltration research at Flushing Meadows Project, Arizona

    SciTech Connect

    Bouwer, H.; Rice, R.C.; Lance, J.C.; Gilbert, R.G.

    1980-10-01

    The Flushing Meadows Project in Arizona was initiated to investigate the feasibility of using wastewater for irrigation and the effects of infiltration on water quality. The results of the second phase of this 10 yr study, focusing on maximization of nitrogen removal and reduction of hydraulic loading, are discussed. Infiltration rates employed in this phase were 0.3-1 m/d, using a water depth of 0.3 m in the six experimental water basins. Removal of dissolved and suspended solids, nitrogen, phosphorus, organic carbon, and pathogens was monitored. Phosphate removal increased with increasing distance of wastewater movement; 65% of the total nitrogen content was removed. (3 graphs, 1 map, 23 references, 3 tables)

  17. A Simple Infiltration Method for Determining Hydraulic Conductivities at Various Depths

    NASA Astrophysics Data System (ADS)

    Chen, C.; Hsu, K.

    2010-12-01

    Soil hydraulic properties usually show high spatial variation. Most infiltration methods assume a uniform hydraulic conductivity and rely on the attainment of a steady state flow rate of water into the soil. In this study, a falling head infiltration method is developed to determine hydraulic conductivities at various depths. Water content sensors at various depths are required to add to the classical ponded infiltration test. The falling head infiltration theory proposed by Philip [1992a] is extended to multiple steps in the proposed method. The Green-Ampt model is used to physically approximate the movement of the wetting front. General analytical solutions for infiltration depth and saturated hydraulic conductivity are derived for a multi-layer soil. The falling head infiltration method is compared to the constant head infiltration method for a homogeneous soil. The results show that the falling head infiltration method is more efficient in water use than is the constant head infiltration method. Then, the proposed method is demonstrated for a two-layer soil system. Numerical experiment results show that with measured variations of water content, the effective arrival time of the wetting front can be well approximated by the average of the start and finish times of the change in water content to obtain the hydraulic conductivity. The calculated hydraulic conductivity is the harmonic mean of the layer soil, and thus hydraulic conductivities at various depths can be estimated sequentially from the top down. The multi-step falling head infiltration method was applied to a sandbox experiment in the laboratory. The experimental results are consistent with the hydraulic conductivity obtained using the constant head ponded infiltration method. The multi-step falling head infiltration method also shows a consistent decrease of hydraulic conductivity in the sand column. The proposed method is less laborious and more versatile than the constant head ponded infiltration

  18. Channel infiltration from floodflows along the Pawnee River and its tributaries, west-central Kansas

    USGS Publications Warehouse

    Gillespie, James B.; Perry, C.A.

    1988-01-01

    Most of the streams is west-central Kansas are ephemeral. Natural recharge to the alluvial aquifers underlying these streams occurs during periods of storm runoff in the ephemeral channels. Proposed flood-retarding structures within the basin will alter the downstream runoff characteristics in these channels by reducing the peak flow and increasing the flow duration. Information concerning channel-infiltration rate, unsaturated and saturated flow, and lithology of the unsaturated zone as related to stream stage and duration was collected along the Pawnee River and its tributaries to determine the effects of the flood-retarding structures. The infiltration rate on ephemeral streams was determined at five sites within the Pawnee River Basin. Tests were conducted in channel infiltrometers constructed by isolating a section of channel with two plastic-lined wooden cofferdams. At two of the sites, perched groundwater mounds intersected the bottom of the channel and reduced the infiltration rate. At two other sites where the perched groundwater mounds did not reach the bottom of the channel, the infiltration rate was directly proportional to the stage. Comparison of infiltration from simulated controlled and uncontrolled floodflows at the five sites indicated an average increase of about 2% with the controlled floodflow. Cumulative infiltration for these simulations ranged from 0.5 to 14.8 acre-ft/mi of channel. (USGS)

  19. Temperature dependence of electrical resistivity measurements: A useful infiltration tracer?

    NASA Astrophysics Data System (ADS)

    Pidlisecky, A.; Knight, R.

    2008-12-01

    As part of an ongoing monitoring project, three resistivity probes were installed to a depth of 2m below a seasonal infiltration pond on the central coast of California. The probes were instrumented with 35 resistivity electrodes and 5 temperature loggers. They were designed to monitor the change in bulk resistivity beneath the pond during infiltration. The pond was filled in January 2008 and resistivity measurements were made on each probe every hour for a period of 4 months. In addition to changes in bulk resistivity, we observed diurnal fluctuations in the apparent resistivity signal due to the temperature dependence of in-situ resistivity. By processing the resistivity data, using a band pass filter, we can recover a time-depth section of pseudo- temperature data. We refer to these data as pseudo-temperature because they can be treated as a surrogate for temperature in terms of phase but not amplitude. These pseudo-temperature sections can be used as a tracer to calculate 1D infiltration rates. When compared with in-situ temperature loggers, we see good agreement. Moreover, we note that the resistivity fluctuations correspond to temperature variations that are less than one degree Celsius. The use of the temperature dependence of measured resistivity is a promising field technique. The pseudo-temperature data may prove more robust than using traditional temperature probes given that the larger sampling volume of the resistivity measurement will limit the influence local flow path perturbations caused by probe installation. Future research will involve extending this approach to 2D tomography in hopes of providing us with a technique for obtaining spatially exhaustive estimates of near-surface infiltration rates.

  20. Fine and ultrafine particle decay rates in multiple homes.

    PubMed

    Wallace, Lance; Kindzierski, Warren; Kearney, Jill; MacNeill, Morgan; Héroux, Marie-Ève; Wheeler, Amanda J

    2013-11-19

    Human exposure to particles depends on particle loss mechanisms such as deposition and filtration. Fine and ultrafine particles (FP and UFP) were measured continuously over seven consecutive days during summer and winter inside 74 homes in Edmonton, Canada. Daily average air exchange rates were also measured. FP were also measured outside each home and both FP and UFP were measured at a central monitoring station. A censoring algorithm was developed to identify indoor-generated concentrations, with the remainder representing particles infiltrating from outdoors. The resulting infiltration factors were employed to determine the continuously changing background of outdoor particles infiltrating the homes. Background-corrected indoor concentrations were then used to determine rates of removal of FP and UFP following peaks due to indoor sources. About 300 FP peaks and 400 UFP peaks had high-quality (median R(2) value >98%) exponential decay rates lasting from 30 min to 10 h. Median (interquartile range (IQR)) decay rates for UFP were 1.26 (0.82-1.83) h(-1); for FP 1.08 (0.62-1.75) h(-1). These total decay rates included, on average, about a 25% contribution from air exchange, suggesting that deposition and filtration accounted for the major portion of particle loss mechanisms in these homes. Models presented here identify and quantify effects of several factors on total decay rates, such as window opening behavior, home age, use of central furnace fans and kitchen and bathroom exhaust fans, use of air cleaners, use of air conditioners, and indoor-outdoor temperature differences. These findings will help identify ways to reduce exposure and risk. PMID:24143863

  1. Lorentz force infiltration of fibrous preforms

    NASA Astrophysics Data System (ADS)

    Andrews, Richard M.; Mortensen, Andreas

    1991-12-01

    A new process for the production of metal matrix composites, whereby molten metal is forced into the interstices of a fibrous preform using electromagnetic body forces, is presented. These forces are created by subjecting the molten matrix to a concentrated transient magnetic field which, in turn, induces intense eddy currents in the melt. This gives rise to Lorentz forces which propel the metal into the preform. Equations governing the mechanics of Lorentz force infiltration of an axisymmetric preform surrounded by molten metal are solved numerically. A finite difference algorithm is applied to solve Maxwell's equation of electromagnetic field propagation and to determine the flux density as a function of radial position. The resulting Lorentz force is then calculated and balanced with the inertial, fluid friction and capillary forces, taking preform compression into account, to predict infiltration velocity and cumulative infiltration distance. Apparatuses were designed and constructed to infiltrate cylindrical preforms of 24 vol pct 3-μm-diameter chopped alumina fiber preforms with commercial purity aluminum. Two capacitor banks were charged from 1 to 4 kV and rapidly discharged to produce magnetic pulses of up to 4 tesla peak, at frequencies of 2 to 3 kHz in the infiltrating furnace. A commercial MAGNEFORM unit was also used to produce fields of up to 5 tesla at 5.6 kHz.-Sound composite samples were produced, to a depth of 1.8 mm into the preforms, with little or no breakage of fibers. Good agreement between theoretical model predictions and experimentally measured infiltration depths was demonstrated. Primary process variables for a given matrix-preform system, were the number of discharges, the magnetic pulse intensity and frequency, and the melt ring thickness. The model predicts a pulse frequency below which infiltration does not occur and an optimum frequency for maximum infiltration depth. Successive pulses are predicted to produce only slightly

  2. Large conversion rates of NO2 to HNO2 observed in air masses from the South China Sea: Evidence of strong production at sea surface?

    NASA Astrophysics Data System (ADS)

    Zha, Qiaozhi; Xue, Likun; Wang, Tao; Xu, Zheng; Yeung, Chungpong; Louie, Peter K. K.; Luk, Connie W. Y.

    2014-11-01

    Nitrous acid (HONO) plays important roles in tropospheric chemistry, but its source(s) are not completely understood. Here we analyze measurements of HONO, nitrogen dioxide (NO2), and related parameters at a coastal site in Hong Kong during September-December 2012. The nocturnal NO2-to-HONO conversion rates were estimated in air masses passing over land and sea surfaces. The conversion rates in the "sea cases" (3.17-3.36 × 10-2 h-1) were significantly higher than those in the "land cases" in our study (1.20-1.30 × 10-2 h-1) and in previous studies by others. These results suggest that air-sea interactions may be a significant source of atmospheric HONO and need to be considered in chemical transport models.

  3. 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

  4. 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

  5. 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…

  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. Factors affecting pressure infiltration of packed SiC particulates by liquid aluminum

    SciTech Connect

    Narciso, J.; Alonso, A.; Pamies, A.; Garcia-Cordovilla, C.; Louis, E.

    1995-04-01

    Pressure infiltration is being currently used to evaluate the wettability of ceramic particles and fibers by liquid metals. The objective of this work is to investigate the effect of type and surface condition of the particulates and infiltration atmosphere on pressure infiltration of packed SiC particulates by pure liquid aluminum, Fourteen SiC particulates from five different suppliers, of green (high purity) and black (low purity) types, were used. Two of the particulates were subjected to either low or high-temperature heat treatments in order to either bum organic residues or promote oxidation. Infiltrations were carried out in air, argon, argon/hydrogen, and nitrogen/hydrogen atmospheres. The results indicate that the threshold pressure does not depend appreciably on the type of particulate. A heat treatment at 600 C improves the infiltration performance of particulates having a large amount of organic residues, whereas oxidation at 1,000 C decreases the threshold pressure. The results also illustrate the effects of the infiltration atmosphere; in particular, it is shown that inert or reducing atmospheres improve wettability.

  8. 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...

  9. A Simulation of the Effects of Varying Repetition Rate and Pulse Width of Nanosecond Discharges on Premixed Lean Methane-Air Combustion

    DOE PAGESBeta

    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

  10. 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.

  11. Greatly increased toughness of infiltrated spider silk.

    PubMed

    Lee, Seung-Mo; Pippel, Eckhard; Gösele, Ulrich; Dresbach, Christian; Qin, Yong; Chandran, C Vinod; Bräuniger, Thomas; Hause, Gerd; Knez, Mato

    2009-04-24

    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. PMID:19390040

  12. Electron Percolation In Copper Infiltrated Carbon

    NASA Astrophysics Data System (ADS)

    Krcho, Stanislav

    2015-11-01

    The work describes the dependence of the electrical conductivity of carbon materials infiltrated with copper in a vacuum-pressure autoclave on copper concentration and on the effective pore radius of the carbon skeleton. In comparison with non-infiltrated material the electrical conductivity of copper infiltrated composite increased almost 500 times. If the composite contained less than 7.2 vol% of Cu, a linear dependence of the electrical conductivity upon cupper content was observed. If infiltrated carbon contained more than 7.2 vol% of Cu, the dependence was nonlinear - the curve could be described by a power formula (x - xc)t. This is a typical formula describing the electron percolation process in regions containing higher Cu fraction than the critical one. The maximum measured electrical conductivity was 396 × 104 Ω-1 m-1 for copper concentration 27.6 vol%. Experiments and analysis of the electrical conductivity showed that electron percolation occurred in carbon materials infiltrated by copper when the copper volume exceeded the critical concentration. The analysis also showed a sharp increase of electrical conductivity in composites with copper concentration higher than the threshold, where the effective radius of carbon skeleton pores decreased to 350 nanometres.

  13. 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.

  14. 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.

  15. 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. PMID:27269664

  16. 40 CFR 35.927-1 - Infiltration/inflow analysis.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 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...

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 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...

  18. 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.

  19. Setting maximum emission rates from ozone emitting consumer appliances in the United States and Canada

    NASA Astrophysics Data System (ADS)

    Morrison, Glenn; Shaughnessy, Richard; Shu, Shi

    2011-02-01

    A Monte Carlo analysis of indoor ozone levels in four cities was applied to provide guidance to regulatory agencies on setting maximum ozone emission rates from consumer appliances. Measured distributions of air exchange rates, ozone decay rates and outdoor ozone levels at monitoring stations were combined with a steady-state indoor air quality model resulting in emission rate distributions (mg h -1) as a function of % of building hours protected from exceeding a target maximum indoor concentration of 20 ppb. Whole-year, summer and winter results for Elizabeth, NJ, Houston, TX, Windsor, ON, and Los Angeles, CA exhibited strong regional differences, primarily due to differences in air exchange rates. Infiltration of ambient ozone at higher average air exchange rates significantly reduces allowable emission rates, even though air exchange also dilutes emissions from appliances. For Houston, TX and Windsor, ON, which have lower average residential air exchange rates, emission rates ranged from -1.1 to 2.3 mg h -1 for scenarios that protect 80% or more of building hours from experiencing ozone concentrations greater than 20 ppb in summer. For Los Angeles, CA and Elizabeth, NJ, with higher air exchange rates, only negative emission rates were allowable to provide the same level of protection. For the 80th percentile residence, we estimate that an 8-h average limit concentration of 20 ppb would be exceeded, even in the absence of an indoor ozone source, 40 or more days per year in any of the cities analyzed. The negative emission rates emerging from the analysis suggest that only a zero-emission rate standard is prudent for Los Angeles, Elizabeth, NJ and other regions with higher summertime air exchange rates. For regions such as Houston with lower summertime air exchange rates, the higher emission rates would likely increase occupant exposure to the undesirable products of ozone reactions, thus reinforcing the need for zero-emission rate standard.

  20. 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.

  1. Improvement of oxygen transfer coefficient during Penicillium canescens culture. Influence of turbine design, agitation speed, and air flow rate on xylanase production.

    PubMed

    Gaspar, A; Strodiot, L; Thonart, P

    1998-01-01

    To improve xylanase productivity from Penicillium canescens 10-10c culture, an optimization of oxygen supply is required. Because the strain is sensitive to shear forces, leading to lower xylanase productivity as to morphological alteration, vigorous mixing is not desired. The influence of turbine design, agitation speed, and air flow rate on K1a (global mass transfer coefficient, h(-1)) and enzyme production is discussed. K1a values increased with agitation speed and air flow rate, whatever the impeller, in our assay conditions. Agitation had more influence on K1a values than air flow, when a disk-mounted blade's impeller (DT) is used; an opposite result was obtained with a hub-mounted pitched blade's impeller (PBT). Xylanase production appeared as a function of specific power (W/m3), and an optimum was found in 20 and 100 L STRs fitted with DT impellers. On the other hand, the use of a hub-mounted pitched blade impeller (PBT8), instead of a disk-mounted blade impeller (DT4), reduced the lag time of hemicellulase production and increased xylanase productivity 1.3-fold. PMID:18576019

  2. Primary cardiac lymphoma mimicking infiltrative cardiomyopathy.

    PubMed

    Lee, Ga Yeon; Kim, Won Seog; Ko, Young-Hyeh; Choi, Jin-Oh; Jeon, Eun-Seok

    2013-05-01

    Primary cardiac lymphoma is a rare malignancy which has been described as thickened myocardium due to the infiltration of atypical lymphocytes and accompanying intracardiac masses. Here, we report a case of a primary cardiac lymphoma without demonstrable intracardiac masses, mimicking infiltrative cardiomyopathy. A 40-year-old male presented with exertional dyspnoea and was diagnosed as having restrictive cardiomyopathy with severely decreased LV systolic function. Endomyocardial biopsy was performed and the diagnosis of primary cardiac lymphoma was confirmed. After appropriate chemotherapy, he recovered his systolic function fully. PMID:23248217

  3. 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.

  4. Reaction Infiltration Instabilities in Partially Molten Rocks

    NASA Astrophysics Data System (ADS)

    Pec, M.; Holtzman, B. K.; Zimmerman, M. E.; Kohlstedt, D. L.

    2015-12-01

    Tabular dunites in ophiolites are thought to form high-permeability, melt channels due to a positive feedback between melt flow and melt-solid reaction in the upper mantle. Reaction-infiltration instability (RII) theory predicts whether or not channels emerge from background flow. To test the applicability of RII theory to mantle rocks, we sandwiched a partially molten rock between a melt reservoir and a porous sink. Hot-pressed 50:50 mixtures of olivine (Ol) and clinopyroxene (Cpx) with either 4, 10 or 20 vol% alkali basalt formed ~4 mm long cylinders of partially molten rock. Source and sink are disks of alkali basalt and porous alumina. We annealed the melt-rock-sink triplets for up to 5 h at a confining pressure of Pc=300 MPa with effective pressure Pe=0 to 299.9 MPa at T=1200° or 1250°C. The melt fraction in the partially molten rock influences the permeability, which, together with the applied pressure gradient, controls the melt migration velocity. The temperature influences the reaction rate. Melt velocity and reaction rate are fundamental parameters in RII theory. In experiments, two distinct features form due to melt migration, 1) a planar reaction layer (RL) and 2) finger-shaped channels. Both the RL and the channels contain Ol+melt with no Cpx, indicating that the reaction melt1+Cpx→melt2+Ol occurs. The channels develop only if the melt velocity is >5µm/s. Once a channel reaches the porous sink, a large increase in the effective permeability is detected. The morphology and spacing of the channels depends on the initial melt fraction. With 20 vol% melt, multiple, voluminous channels with a spacing of 1.8±0.5 mm develop. At lower melt contents, fewer, thinner channels with a spacing of ~3 mm develop. The channel spacing predicted by theory is about a factor 2-4 smaller than observed. Our results indicate that RII theory provides a solid framework for investigating melt migration in experiments and potentially a basis for extrapolation to mantle

  5. 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

  6. 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.

  7. 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.

  8. Theoretical study of the effect of liquid desiccant mass flow rate on the performance of a cross flow parallel-plate liquid desiccant-air dehumidifier

    NASA Astrophysics Data System (ADS)

    Mohammad, Abdulrahman Th.; Mat, Sohif Bin; Sulaiman, M. Y.; Sopian, K.; Al-abidi, Abduljalil A.

    2013-11-01

    A computer simulation using MATLAB is investigated to predict the distribution of air stream parameters (humidity ratio and temperature) as well as desiccant parameters (temperature and concentration) inside the parallel plate absorber. The present absorber consists of fourteen parallel plates with a surface area per unit volume ratio of 80 m2/m3. Calcium chloride as a liquid desiccant flows through the top of the plates to the bottom while the air flows through the gap between the plates making it a cross flow configuration. The model results show the effect of desiccant mass flow rate on the performance of the dehumidifier (moisture removal and dehumidifier effectiveness). Performance comparisons between present cross-flow dehumidifier and another experimental cross-flow dehumidifier in the literature are carried out. The simulation is expected to help in optimizing of a cross flow dehumidifier.

  9. Measurements of VOC/SVOC emission factors from burning incenses in an environmental test chamber: influence of temperature, relative humidity, and air exchange rate.

    PubMed

    Manoukian, A; Buiron, D; Temime-Roussel, B; Wortham, H; Quivet, E

    2016-04-01

    This study investigates the influence of three environmental indoor parameters (i.e., temperature, relative humidity, and air exchange rate) on the emission of 13 volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) during incense burning. Experiments have been carried out using an environmental test chamber. Statistical results from a classical two-level full factorial design highlight the predominant effect of ventilation on emission factors. The higher the ventilation, the higher the emission factor. Moreover, thanks to these results, an estimation of the concentration range for the compounds under study can be calculated and allows a quick look of indoor pollution induced by incense combustion. Carcinogenic substances (i.e., benzene, benzo(a)pyrene, and formaldehyde) produced from the incense combustion would be predicted in typical living indoors conditions to reach instantaneous concentration levels close to or higher than air quality exposure threshold values. PMID:26614451

  10. 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.

  11. 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

  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. Evaluation of Net Infiltration Uncertainty for Multiple Uncertain Input Parameters Using Latin Hypercube Sampling

    NASA Astrophysics Data System (ADS)

    Faybishenko, B.; McCurley, R. D.; Wang, J. Y.

    2004-12-01

    To assess, via numerical simulation, the effect of 12 uncertain input parameters (characterizing soil and rock properties and boundary [meteorological] conditions), on net infiltration uncertainty, the Latin Hypercube Sampling (LHS) technique (a modified Monte Carlo approach using a form of stratified sampling) was used. Each uncertain input parameter is presented using a probability distribution function, characterizing the epistemic uncertainty (which arises from the lack of knowledge about parameters-an uncertainty that can be reduced as new information becomes available). One hundred LHS realizations (using the code LHS V2.50 developed at Sandia National Laboratories) of the uncertain input parameters were used to simulate the net infiltration over the Yucca Mountain repository footprint. Simulations were carried out using the code INFIL VA-2.a1 (a modified USGS code INFIL V2.0). The results of simulations were then used to determine the net infiltration probability distribution function. According to theoretical considerations, for 12 uncertain input parameters, from 15 to 36 realizations using the LHS technique should be sufficient to get meaningful results. In this presentation, we will show that the theoretical considerations may significantly underestimate the required number of realizations for the evaluation of the correlation between the net infiltration and uncertain input parameters. We will demonstrate that the calculated net infiltration rate (presented as a probability distribution function) oscillates as a function of simulation runs, and that the correlation between net infiltration rate and the uncertain input parameters depends on the number of simulation runs. For example, the correlation coefficient between the soil (or rock) permeability and net infiltration stabilizes only after 60-80 realizations. The results of the correlation analysis show that the correlation to net infiltration is highest for precipitation, bedrock permeability

  14. Water and Air Redistribution within a Dual Permeability Porous System Investigated Using Neutron Imaging

    NASA Astrophysics Data System (ADS)

    Sacha, Jan; Jelinkova, Vladimira; Snehota, Michal; Vontobel, Peter; Hovind, Jan; Cislerova, Milena

    A ponded infiltration experiment was conducted under simultaneous imaging to investigate variations in quasi-saturated hydraulic conductivity a process frequently observed in infiltration experiments in soils with wide grain -size distribution. An artificially prepared heterogeneous sample composed of coarse quartz sand (representing pathways of preferential flow) and fine porous ceramic (representing soil matrix) was investigated. The sample was 34.5 mm high and 29.0 mm in diameter. Sequences of neutron radiography images (RI) of pixel size 0.045 × 0.045 mm were taken at one angle during particular transient phases of the flow process. During quasi-steady state flow stages of the experiment radiography images were acquired in range of angles 0-180° in 0.9° step and. 3D neutron tomograms (TI) were then developed. Using the data a quantitative evaluation of the spatial and temporal distribution of water content within the sample was conducted. For every RI and TI the amount of water in particular pixels and voxels, respectively, was calculated by subtracting the image of dry sample. The accuracy of the water content estimates derived from the images was checked by comparing them to the corresponding gravimetrically determined water content data. Heavy water with equilibrium air saturation was introduced into the sample during two recurrent infiltrations. Thirty five hours later, during second infiltration, the inflow was switched to degassed heavy water in order to remove residual air present in the sample. During the first twelve hours of first infiltration run flow rate through the sample decreased from 3.7 cm/hour to 1.0 cm/hour at the end of the "steady state flow" stage. The flow rate in second run decreased from 3.6 cm/hour to 1.6 cm/hour. Comparison of the tomogram of the sample at the beginning and one taken at the end of the steady state flow stage in each run shows an increase of water content in the porous ceramic, while the water content in the coarse

  15. Passive bioventing driven by natural air exchange

    SciTech Connect

    Foor, D.C.; Zwick, T.C.; Hinchee, R.E.; Hoeppel, R.E.; Kyburg, C.; Bowling, L.

    1995-12-31

    Bioventing wells installed in the vadose zone of petroleum-contaminated sites at the Marine Corps Air Ground Combat Center (MCAGCC) in Twentynine Palms, California, naturally inhale and exhale air. This natural air exchange appears to be driven primarily by barometric pressure changes. The natural air exchange was utilized to engineer a passive bioventing system in which a valve allows only air injection and prevents soil gas extraction. The system is effective in aerating petroleum-contaminated, oxygen-limited subsurface soils. This aeration resulted in enhanced biological activity and site remediation. The bioventing wells (vent wells) were fitted with a passive valve mechanism that opens when the atmospheric pressure overcomes the internal vent well pressure. When the valve is open it permits atmospheric air to enter the vent well and infiltrate into the soil, thereby stimulating bioremediation. When the vent well pressure overcomes atmospheric pressure, the valve is closed and inhibits soil gas extraction. The vent wells are installed in a coarse sand where the depth to groundwater is approximately 220 ft (67 m). Generally, deeper vent wells produce greater flowrates. Passive airflow rates of up to 7 cfm (12 m{sup 3}/h) have been achieved at the bioventing wells.

  16. Point estimation of soil water infiltration process using Artificial Neural Networks for some calcareous soils

    NASA Astrophysics Data System (ADS)

    Parchami-Araghi, Farzin; Mirlatifi, Seyed Majid; Ghorbani Dashtaki, Shoja; Mahdian, Mohmmad Hossein

    2013-02-01

    SummaryInfiltration process is one of the most important components of the hydrological cycle. The direct measurement of infiltration is laborious, time consuming, expensive, and often involves large spatial and temporal variability. Thus, any indirect estimation of this process is quite helpful. The main objective of this study was to predict the cumulative infiltration at specific time steps, using readily available soil data and Artificial Neural Networks (ANNs). 210 double ring infiltration data were collected from different regions of Iran. Basic soil properties of the two upper pedogenic layers (A and B horizons) including initial soil water content, soil water contents at field capacity (-33 kPa) and permanent wilting point (-1500 kPa), bulk density, particle-size distributions, organic carbon, gravel content (>2 mm size), and CaCO3 content were determined. The feedforward multilayer perceptron ANN model was used to predict the cumulative infiltration at 5, 10, 15, 20, 30, 45, 60, 90, 120, 150, 180, 210, 240, and 270 min after the start of the infiltration experiment and at the time of the basic infiltration rate. The developed ANN models were categorized to type I and type II ANN models. The basic soil properties of the first upper soil horizon were hierarchically used as inputs to develop type I ANN models. In contrast, the type II ANN models were developed while the available soil properties of the two upper soil horizons were implemented as inputs using principal component analysis technique. Results of the reliability test for the developed ANN models indicated that type I ANN models with a RMSE of 1.136-9.312 cm had the best performance in estimating the cumulative infiltration. Type I ANN models with the mean RMSD of 6.307 cm had the best performance in estimating the cumulative infiltration curve (CIC). Results indicated that at the 1% probability level, ANNs-derived CIC can be accepted as one of the replications of a reliable infiltration experiment

  17. 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.…

  18. Effects of rainfall characteristics on infiltration and redistribution patterns in revegetation-stabilized desert ecosystems

    NASA Astrophysics Data System (ADS)

    Wang, Xin-Ping; Cui, Yan; Pan, Yan-Xia; Li, Xin-Rong; Yu, Z.; Young, M. H.

    2008-08-01

    SummaryRainfall, the dominant source of water replenishment in the semi-arid sand dune area of north-western China, plays an important role in sustaining the desert ecosystem. An experiment to measure water balance associated with infiltration events was conducted on the re-vegetated sand dunes in the Tengger Desert, north-western China. The redistribution of infiltrated moisture in the course of percolation, root extraction, and evapotranspiration pathways was investigated for a period of 45 days during the growing season. Time domain reflectometry probes were inserted horizontally at 12 different depths below the ground surface in the Caragana korshinskii dwarf-shrub community to record volumetric soil moisture at hourly intervals. Rainfall events were sporadic with widely different intensities during the period of the experiment. The presence of vegetation markedly influenced the infiltration and redistribution patterns on the stabilized sand dunes. Infiltration rates varied greatly with individual rainfall quantity and antecedent soil moisture, with drier soil profile facilitating infiltration. The relationship between infiltration rate and rainfall intensity was linear, with infiltration rate at 80% the magnitude of rainfall intensity. Contrasts between the infiltration rate and cumulative infiltration varied with the feature of rainfall events of the vegetation-stabilized desert soil and the un-vegetated bare desert soil indicate that the measured precipitation alone is insufficient to explain the effective rainfall of the studied regions. At rainfall amount <8.2 mm, with rainfall intensity <0.5 mm h -1, no soil moisture was gained for the re-vegetated soil, while for the bare soil the comparable values were <6.4 mm, and <0.7 mm h -1, respectively. Root withdrawal of soil water and evapotranspiration (reaching 69-90% of precipitation) restricted the wetting front penetration for the vegetated soil. In contrast, the bare soil was prone to infiltration zone

  19. Influence of photon energy spectra from brachytherapy sources on Monte Carlo simulations of kerma and dose rates in water and air

    SciTech Connect

    Rivard, Mark J.; Granero, Domingo; Perez-Calatayud, Jose; Ballester, Facundo

    2010-02-15

    Purpose: For a given radionuclide, there are several photon spectrum choices available to dosimetry investigators for simulating the radiation emissions from brachytherapy sources. This study examines the dosimetric influence of selecting the spectra for {sup 192}Ir, {sup 125}I, and {sup 103}Pd on the final estimations of kerma and dose. Methods: For {sup 192}Ir, {sup 125}I, and {sup 103}Pd, the authors considered from two to five published spectra. Spherical sources approximating common brachytherapy sources were assessed. Kerma and dose results from GEANT4, MCNP5, and PENELOPE-2008 were compared for water and air. The dosimetric influence of {sup 192}Ir, {sup 125}I, and {sup 103}Pd spectral choice was determined. Results: For the spectra considered, there were no statistically significant differences between kerma or dose results based on Monte Carlo code choice when using the same spectrum. Water-kerma differences of about 2%, 2%, and 0.7% were observed due to spectrum choice for {sup 192}Ir, {sup 125}I, and {sup 103}Pd, respectively (independent of radial distance), when accounting for photon yield per Bq. Similar differences were observed for air-kerma rate. However, their ratio (as used in the dose-rate constant) did not significantly change when the various photon spectra were selected because the differences compensated each other when dividing dose rate by air-kerma strength. Conclusions: Given the standardization of radionuclide data available from the National Nuclear Data Center (NNDC) and the rigorous infrastructure for performing and maintaining the data set evaluations, NNDC spectra are suggested for brachytherapy simulations in medical physics applications.

  20. Role of osteopontin in hepatic neutrophil infiltration during alcoholic steatohepatitis

    SciTech Connect

    Apte, Udayan M.; Banerjee, Atrayee; McRee, Rachel; Wellberg, Elizabeth; Ramaiah, Shashi K. . E-mail: sramaiah@cvm.tamu.edu

    2005-08-22

    Alcoholic liver disease (ALD) is a major complication of heavy alcohol (EtOH) drinking and is characterized by three progressive stages of pathology: steatosis, steatohepatitis, and fibrosis/cirrhosis. Alcoholic steatosis (AS) is the initial stage of ALD and consists of fat accumulation in the liver accompanied by minimal liver injury. AS is known to render the hepatocytes increasingly sensitive to toxicants such as bacterial endotoxin (LPS). Alcoholic steatohepatitis (ASH), the second and rate-limiting step in the progression of ALD, is characterized by hepatic fat accumulation, neutrophil infiltration, and neutrophil-mediated parenchymal injury. However, the pathogenesis of ASH is poorly defined. It has been theorized that the pathogenesis of ASH involves interaction of increased circulating levels of LPS with hepatocytes being rendered highly sensitive to LPS due to heavy EtOH consumption. We hypothesize that osteopontin (OPN), a matricellular protein (MCP), plays an important role in the hepatic neutrophil recruitment due to its enhanced expression during the early phase of ALD (AS and ASH). To study the role of OPN in the pathogenesis of ASH, we induced AS in male Sprague-Dawley rats by feeding EtOH-containing Lieber-DeCarli liquid diet for 6 weeks. AS rats experienced extensive fat accumulation and minimal liver injury. Moderate induction in OPN was observed in AS group. ASH was induced by feeding male Sprague-Dawley rats EtOH-containing Lieber-DeCarli liquid diet for 6 weeks followed by LPS injection. The ASH rats had substantial neutrophil infiltration, coagulative oncotic necrosis, and developed higher liver injury. Significant increases in the hepatic and circulating levels of OPN was observed in the ASH rats. Higher levels of the active, thrombin-cleaved form of OPN in the liver in ASH group correlated remarkably with hepatic neutrophil infiltration. Finally, correlative studies between OPN and hepatic neutrophil infiltration was corroborated in a simple