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Sample records for air humidity wind

  1. Instructions for observing air temperature, humidity, and direction and force of wind

    USGS Publications Warehouse

    U.S. Geological Survey

    1892-01-01

    Description of instruments.-The temperature and humidity of the air are obtained from the simultaneous observation of a pair of mercurial thermometers termed the dry and the wet bulb. The air temperature is given by the dry-bulb thermometer, and the humidity is obtained from the combined readings of both. The wet-bulb thermometer differs from the dry-bulb thermometer only in having its bulb covered with thin muslin, which is wetted in pure water at each observation.The two thermometers are fastened in a light metal 'or wooden frame. To this frame is to be attached a stout cord for the whirling of the thermometers, which is an essential part of every observation.

  2. 40 CFR 89.326 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air supply. Air that has had its absolute humidity altered is considered humidity- conditioned air. For...

  3. 40 CFR 89.326 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air supply. Air that has had its absolute humidity altered is considered humidity- conditioned air. For...

  4. 40 CFR 89.326 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air supply. Air that has had its absolute humidity altered is considered humidity- conditioned air. For...

  5. 40 CFR 89.326 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air supply. Air that has had its absolute humidity altered is considered humidity- conditioned air. For...

  6. 40 CFR 89.326 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air supply. Air that has had its absolute humidity altered is considered humidity- conditioned air. For...

  7. Effects of ambient air temperature, humidity, and wind speed on seminal traits in Braford and Nellore bulls at the Brazilian Pantanal

    NASA Astrophysics Data System (ADS)

    Menegassi, Silvio Renato Oliveira; Pereira, Gabriel Ribas; Bremm, Carolina; Koetz, Celso; Lopes, Flávio Guiselli; Fiorentini, Eduardo Custódio; McManus, Concepta; Dias, Eduardo Antunes; da Rocha, Marcela Kuczynski; Lopes, Rubia Branco; Barcellos, Júlio Otávio Jardim

    2016-04-01

    The aim of this study was to evaluate the bioclimatic thermal stress assessed by Equivalent Temperature Index (ETI) and Temperature Humidity Index (THI) on Braford and Nellore bulls sperm quality during the reproductive seasons at the tropical region in the Brazilian Pantanal. We used 20 bulls aged approximately 24 months at the beginning of the study. Five ejaculates per animal were collected using an electroejaculator. Temperature, air humidity, and wind speed data were collected every hour from the automatic weather station at the National Institute of Meteorology. Infrared thermography images data were collected to assess the testicular temperature gradient in each animal. Data were analyzed with ANOVA using MIXED procedure of SAS and means were compared using Tukey's HSD test. The THI and ETI at 12 days (epididymal transit) were higher in January (89.7 and 28.5, respectively) and February (90.0 and 29.0, respectively) compared to other months (P < 0.01). Total seminal defects differ only in Bradford bulls between the months of November and February. Nellore bulls had lower major defects (MaD) and total defects (TD) compared to Braford. Nellore bulls showed correlation between minor defects (MiD) and THI for 30 days (0.90) and 18 days (0.88; P < 0.05). Braford bulls showed correlation for MaD (0.89) in ETI for 12 days (P < 0.05). Infrared thermography showed no difference between animals. Reproductive response to environmental changes is a consequence of Nellore and Braford adaptation to climate stress conditions. Both THI and ETI environmental indexes can be used to evaluate the morphological changes in the seminal parameters in Nellore or Braford bulls; however, more experiments should be performed focusing on larger sample numbers and also in reproductive assessment during the consecutive years to assess fertility potential.

  8. Influence of air pressure, humidity, solar radiation, temperature, and wind speed on ambulatory visits due to chronic obstructive pulmonary disease in Bavaria, Germany

    NASA Astrophysics Data System (ADS)

    Ferrari, Uta; Exner, Teresa; Wanka, Eva R.; Bergemann, Christoph; Meyer-Arnek, Julian; Hildenbrand, Beate; Tufman, Amanda; Heumann, Christian; Huber, Rudolf M.; Bittner, Michael; Fischer, Rainald

    2012-01-01

    Chronic obstructive pulmonary disease (COPD) is one of the most important causes of morbidity and mortality in the world. The disease is often aggravated by periods of increased symptoms requiring medical attention. Among the possible triggers for these exacerbations, meteorological factors are under consideration. The objective of this study was to assess the influence of various meteorological factors on the health status of patients with COPD. For this purpose, the daily number of ambulatory care visits due to COPD was analysed in Bavaria, Germany, for the years 2006 and 2007. The meteorological factors were provided by the model at the European Centre for Medium Range Weather Forecast (ECMWF). For the multivariate analysis, a generalised linear model was used. In Bavaria, an increase of 1% of daily consultations (about 103 visits per day) was found to be associated with a change of 0.72 K temperature, 209.55 of log air surface pressure in Pa, and a decrease of 1% of daily consultations with 1,453,763 Ws m2 of solar radiation. There also seem to be regional differences between north and south Bavaria; for instance, the effect of wind speed and specific humidity with a lag of 1 day were only significant in the north. This study could contribute to a tool for the prevention of exacerbations. It also serves as a model for the further evaluation of the impact of meteorological factors on health, and could easily be applied to other diseases or other regions.

  9. Influence of air pressure, humidity, solar radiation, temperature, and wind speed on ambulatory visits due to chronic obstructive pulmonary disease in Bavaria, Germany.

    PubMed

    Ferrari, Uta; Exner, Teresa; Wanka, Eva R; Bergemann, Christoph; Meyer-Arnek, Julian; Hildenbrand, Beate; Tufman, Amanda; Heumann, Christian; Huber, Rudolf M; Bittner, Michael; Fischer, Rainald

    2012-01-01

    Chronic obstructive pulmonary disease (COPD) is one of the most important causes of morbidity and mortality in the world. The disease is often aggravated by periods of increased symptoms requiring medical attention. Among the possible triggers for these exacerbations, meteorological factors are under consideration. The objective of this study was to assess the influence of various meteorological factors on the health status of patients with COPD. For this purpose, the daily number of ambulatory care visits due to COPD was analysed in Bavaria, Germany, for the years 2006 and 2007. The meteorological factors were provided by the model at the European Centre for Medium Range Weather Forecast (ECMWF). For the multivariate analysis, a generalised linear model was used. In Bavaria, an increase of 1% of daily consultations (about 103 visits per day) was found to be associated with a change of 0.72 K temperature, 209.55 of log air surface pressure in Pa, and a decrease of 1% of daily consultations with 1,453,763 Ws m(2) of solar radiation. There also seem to be regional differences between north and south Bavaria; for instance, the effect of wind speed and specific humidity with a lag of 1 day were only significant in the north. This study could contribute to a tool for the prevention of exacerbations. It also serves as a model for the further evaluation of the impact of meteorological factors on health, and could easily be applied to other diseases or other regions. PMID:21301889

  10. Air motion determination by tracking humidity patterns in isentropic layers

    NASA Technical Reports Server (NTRS)

    Mancuso, R. L.; Hall, D. J.

    1975-01-01

    Determining air motions by tracking humidity patterns in isentropic layers was investigated. Upper-air rawinsonde data from the NSSL network and from the AVE-II pilot experiment were used to simulate temperature and humidity profile data that will eventually be available from geosynchronous satellites. Polynomial surfaces that move with time were fitted to the mixing-ratio values of the different isentropic layers. The velocity components of the polynomial surfaces are part of the coefficients that are determined in order to give an optimum fitting of the data. In the mid-troposphere, the derived humidity motions were in good agreement with the winds measured by rawinsondes so long as there were few or no clouds and the lapse rate was relatively stable. In the lower troposphere, the humidity motions were unreliable primarily because of nonadiabatic processes and unstable lapse rates. In the upper troposphere, the humidity amounts were too low to be measured with sufficient accuracy to give reliable results. However, it appears that humidity motions could be used to provide mid-tropospheric wind data over large regions of the globe.

  11. 40 CFR 91.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply....

  12. 40 CFR 91.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply....

  13. 40 CFR 91.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply....

  14. 40 CFR 91.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply....

  15. 40 CFR 91.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply....

  16. 40 CFR 90.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a)...

  17. 40 CFR 90.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a)...

  18. 40 CFR 90.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a)...

  19. 40 CFR 90.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a)...

  20. 40 CFR 90.310 - Engine intake air humidity measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a)...

  1. Acoustic method for measuring air temperature and humidity in rooms

    NASA Astrophysics Data System (ADS)

    Kanev, N. G.

    2014-05-01

    A method is proposed to determine air temperature and humidity in rooms with a system of sound sources and receivers, making it possible to find the sound velocity and reverberation time. Nomograms for determining the air temperature and relative air humidity are constructed from the found sound velocity and time reverberation values. The required accuracy of measuring these parameters is estimated.

  2. Relationship of air temperature, relative humidity, precipitation, photoperiod, wind speed and solar radiation with serum insulin-like growth factor I (IGF-I) concentration in Angus beef cattle.

    PubMed

    Sarko, T A; Bishop, M D; Davis, M E

    1994-07-01

    Eight paternal half-sib Angus calves born in late April and early May, 1988 were used to investigate the potential relationship of serum IGF-I concentration with photoperiod and various weather variables including minimum, maximum and average air temperatures, relative humidity, precipitation, wind speed and solar radiation. To determine IGF-I concentration, blood samples were obtained at birth and then weekly until the calves reached 1 mo of age and bi-weekly thereafter. Blood sampling continued until the calves reached puberty as determined by progesterone and testosterone assays. Photoperiod and each weather variable were averaged over the 3 d prior to and including the day of blood sampling (4-d average). Data were divided into two periods: (1) birth through the end of the postweaning period and (2) postweaning period only. Serum IGF-I concentrations were analyzed using a model which included the fixed effects of sex and sample number, the random effect of calf nested within sex and the fixed interaction of sex x sample number, in addition to covariates for weight, photoperiod and weather variables. From birth through the end of the postweaning test, none of the weather variables or photoperiod had significant effects on serum IGF-I concentrations when each was fitted separately. For the postweaning period only, cubic regression coefficients for minimum and average temperatures were .0962 +/- .0325 ng/ml/degrees C3 and .0976 +/- .0272 ng/ml/degrees C3, respectively (P < .01). The quadratic regression coefficient for relative humidity during the postweaning period was -.2991 +/- .1142 ng/ml/%2 (P < .05). The quartic regression coefficient for wind speed during the postweaning period was -36.435 +/- 13.00 ng/ml/(km/hr)4 (P < .01). Maximum temperature, precipitation, solar radiation and photoperiod did not have significant effects on postweaning serum IGF-I concentrations. Based on these data, we conclude that temperature, humidity and wind speed were contributing

  3. Temperature, Humidity, Wind and Pressure Sensors (THWAPS) Handbook

    SciTech Connect

    Ritsche, MT

    2011-01-17

    The temperature, humidity, wind, and pressure system (THWAPS) provide surface reference values of these measurements for balloon-borne sounding system (SONDE) launches. The THWAPS is located adjacent to the SONDE launch site at the Southern Great Plains (SGP) Central Facility. The THWAPS system is a combination of calibration-quality instruments intended to provide accurate measurements of meteorological conditions near the surface. Although the primary use of the system is to provide accurate surface reference values of temperature, pressure, relative humidity (RH), and wind velocity for comparison with radiosonde readings, the system includes a data logger to record time series of the measured variables.

  4. HUMID AIR TURBINE CYCLE TECHNOLOGY DEVELOPMENT PROGRAM

    SciTech Connect

    Richard Tuthill

    2002-07-18

    The Humid Air Turbine (HAT) Cycle Technology Development Program focused on obtaining HAT cycle combustor technology that will be the foundation of future products. The work carried out under the auspices of the HAT Program built on the extensive low emissions stationary gas turbine work performed in the past by Pratt & Whitney (P&W). This Program is an integral part of technology base development within the Advanced Turbine Systems Program at the Department of Energy (DOE) and its experiments stretched over 5 years. The goal of the project was to fill in technological data gaps in the development of the HAT cycle and identify a combustor configuration that would efficiently burn high moisture, high-pressure gaseous fuels with low emissions. The major emphasis will be on the development of kinetic data, computer modeling, and evaluations of combustor configurations. The Program commenced during the 4th Quarter of 1996 and closed in the 4th Quarter of 2001. It teamed the National Energy Technology Laboratory (NETL) with P&W, the United Technologies Research Center (UTRC), and a subcontractor on-site at UTRC, kraftWork Systems Inc. The execution of the program started with bench-top experiments that were conducted at UTRC for extending kinetic mechanisms to HAT cycle temperature, pressure, and moisture conditions. The fundamental data generated in the bench-top experiments was incorporated into the analytical tools available at P&W to design the fuel injectors and combustors. The NETL then used the hardware to conduct combustion rig experiments to evaluate the performance of the combustion systems at elevated pressure and temperature conditions representative of the HAT cycle. The results were integrated into systems analysis done by kraftWork to verify that sufficient understanding of the technology had been achieved and that large-scale technological application and demonstration could be undertaken as follow-on activity. An optional program extended the

  5. Characteristics of dielectric barrier discharge plasmas in atmospheric humid air

    NASA Astrophysics Data System (ADS)

    Fukuda, Y.; Fukui, K.; Iwami, R.; Matsuoka, Y.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2012-10-01

    Atmospheric pressure plasmas have a great advantage for industrial applications such as surface modifications, sterilization and film preparation. In particular, reactive plasmas including OH radicals can be generated in humid air. On the other hand, it is known that dielectric barrier discharge (DBD) plasmas in air are strongly affected by humidity. In this study, a twisted pair sample is used as a DBD electrode. The twisted pair consists of two enameled wires, and it is installed in a climate chamber to control ambient temperature and humidity. Repetitive impulse voltage pulses were applied to the twisted pair to produce DBD plasmas. Light emission, electromagnetic wave and current pulses were used to detect discharge activities. The discharge inception voltage (DIV) is basically determined by Paschen curve in air, however, the DIV was decreased by increasing the humidity. In addition, it was found that there were largely scattered data of DIV at the low humidity condition. After the pre-discharges, the DIV reached to the steady state value. On the other hand, there was no scattering of the observed DIV at the high humidity condition. Measurements of surface potential of the sample after the discharge show these behaviors could be explained by surface charge accumulation on the enameled wire. It is noted that there was no fluctuation in the DIV data in the case of unipolar voltage pulse.

  6. Ambient humidity and the skin: the impact of air humidity in healthy and diseased states.

    PubMed

    Goad, N; Gawkrodger, D J

    2016-08-01

    Humidity, along with other climatic factors such as temperature and ultraviolet radiation, can have an important impact on the skin. Limited data suggest that external humidity influences the water content of the stratum corneum. An online literature search was conducted through Pub-Med using combinations of the following keywords: skin, skin disease, humidity, dermatoses, dermatitis, eczema, and mist. Publications included in this review were limited to (i) studies in humans or animals, (ii) publications showing relevance to the field of dermatology, (iii) studies published in English and (iv) publications discussing humidity as an independent influence on skin function. Studies examining environmental factors as composite influences on skin health are only included where the impact of humidity on the skin is also explored in isolation of other environmental factors. A formal systematic review was not feasible for this topic due to the heterogeneity of the available research. Epidemiological studies indicated an increase in eczema with low internal (indoors) humidity and an increase in eczema with external high humidity. Other studies suggest that symptoms of dry skin appear with low humidity internal air-conditioned environments. Murine studies determined that low humidity caused a number of changes in the skin, including the impairment of the desquamation process. Studies in humans demonstrated a reduction in transepidermal water loss (TEWL) (a measure of the integrity of the skin's barrier function) with low humidity, alterations in the water content in the stratum corneum, decreased skin elasticity and increased roughness. Intervention with a humidifying mist increased the water content of the stratum corneum. Conversely, there is some evidence that low humidity conditions can actually improve the barrier function of the skin. Ambient relative humidity has an impact on a range of parameters involved in skin health but the literature is inconclusive. Further

  7. Volatilization modeling of two herbicides from soil in a wind tunnel experiment under varying humidity conditions.

    PubMed

    Schneider, Martina; Goss, Kai-Uwe

    2012-11-20

    Volatilization of pesticides from the bare soil surface is drastically reduced when the soil is under dry conditions (i.e., water content lower than the permanent wilting point). This effect is caused by the hydrated mineral surfaces that become available as additional sorption sites under dry conditions. However, established volatilization models do not explicitly consider the hydrated mineral surfaces as an independent sorption compartment and cannot correctly cover the moisture effect on volatilization. Here we integrated the existing mechanistic understanding of sorption of organic compounds to mineral surfaces and its dependence on the hydration status into a simple volatilization model. The resulting model was tested with reported experimental data for two herbicides from a wind tunnel experiment under various well-defined humidity conditions. The required equilibrium sorption coefficients of triallate and trifluralin to the mineral surfaces, K(min/air), at 60% relative humidity were fitted to experimental data and extrapolated to other humidity conditions. The model captures the general trend of the volatilization in different humidity scenarios. The results reveal that it is essential to have high quality input data for K(min/air), the available specific surface area (SSA), the penetration depth of the applied pesticide solution, and the humidity conditions in the soil. The model approach presented here in combination with an improved description of the humidity conditions under dry conditions can be integrated into existing volatilization models that already work well for humid conditions but still lack the mechanistically based description of the volatilization process under dry conditions. PMID:23130847

  8. A physically based analytical spatial air temperature and humidity model

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Endreny, Theodore A.; Nowak, David J.

    2013-09-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the same mesoscale climate, grid air temperature and humidity are modified by local variation in absorbed solar radiation and the partitioning of sensible and latent heat. The model uses a reference grid site for time series meteorological data and the air temperature and humidity of any other grid can be obtained by solving the heat flux network equations. PASATH was coupled with the USDA iTree-Hydro water balance model to obtain evapotranspiration terms and run from 20 to 29 August 2010 at a 360 m by 360 m grid scale and hourly time step across a 285 km2 watershed including the urban area of Syracuse, NY. PASATH predictions were tested at nine urban weather stations representing variability in urban topography and land cover. The PASATH model predictive efficiency R2 ranged from 0.81 to 0.99 for air temperature and 0.77 to 0.97 for dew point temperature. PASATH is expected to have broad applications on environmental and ecological models.

  9. Effect of wind speed and relative humidity on atmospheric dust concentrations in semi-arid climates.

    PubMed

    Csavina, Janae; Field, Jason; Félix, Omar; Corral-Avitia, Alba Y; Sáez, A Eduardo; Betterton, Eric A

    2014-07-15

    Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (>4m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport. PMID:24769193

  10. Effect of Wind Speed and Relative Humidity on Atmospheric Dust Concentrations in Semi-Arid Climates

    PubMed Central

    Csavina, Janae; Field, Jason; Félix, Omar; Corral-Avitia, Alba Y.; Sáez, A. Eduardo; Betterton, Eric A.

    2014-01-01

    Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (> 4 m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport. PMID:24769193

  11. Humidity variations across the edge of trade wind cumuli: Observations and dynamical implications

    NASA Astrophysics Data System (ADS)

    Wang, Yonggang; Geerts, Bart

    2010-07-01

    Aircraft data are used to analyze the composite horizontal structure of shallow tropical maritime cumulus clouds across the cloud edge into the ambient clear air. The emphasis is on humidity variations, and their implications for cumulus dynamics. The Lyman-α humidity probe has the required fast response and is unaffected by wetting in-cloud. On average the water vapor mixing ratio increases gradually from the clear air towards the cloud edge, and air is often sub-saturated in the outer fringe of the cloud, implying that droplets are evaporating. Similarly, conserved variables such as the total water concentration and the wet equivalent potential temperature gradually transition in the "margin" of cumulus clouds. The gradual change of water vapor mixing ratio and conserved variables across the cloud edge highlights the significance of lateral entrainment and detrainment, and it reveals a characteristic penetration depth of mixing eddies of 10 to 15% of the cloud diameter, or about 50 m. An ˜ 100 m wide region just outside the cloud is generally characterized by negatively buoyant, sinking air. The excess water vapor in this region, also documented in several recent studies, confirms that the negative buoyancy is caused by evaporative cooling in the cloud margin. Although rather weak, this cooling appears strong enough to evoke a dynamical response, even in the relative small trade wind cumuli.

  12. Significance of air humidity and air velocity for fungal spore release into the air

    NASA Astrophysics Data System (ADS)

    Pasanen, A.-L.; Pasanen, P.; Jantunen, M. J.; Kalliokoski, P.

    Our previous field studies have shown that the presence of molds in buildings does not necessarily mean elevated airborne spore counts. Therefore, we investigated the release of fungal spores from cultures of Aspergillus fumigatus, Penicillium sp. and Cladosporium sp. at different air velocities and air humidities. Spores of A. fumigatus and Penicillium sp. were released from conidiophores already at air velocity of 0.5 ms -1, whereas Cladosporium spores required at least a velocity of 1.0 ms -1. Airborne spore counts of A. fumigatus and Penicillium sp. were usually higher in dry than moist air, being minimal at relative humidities (r.h.) above 70%, while the effect of r.h. on the release of Cladosporium sp. was ambivalent. The geometric mean diameter of released spores increased when the r.h. exceeded a certain level which depends on fungal genus. Thus, spores of all three fungi were hygroscopic but the hygroscopicity of various spores appeared at different r.h.-ranges. This study indicates that spore release is controlled by external factors and depends on fungal genus which can be one reason for considerable variation of airborne spore counts in buildings with mold problems.

  13. Biphilic Surfaces for Enhanced Water Collection from Humid Air

    NASA Astrophysics Data System (ADS)

    Benkoski, Jason; Gerasopoulos, Konstantinos; Luedeman, William

    Surface wettability plays an important role in water recovery, distillation, dehumidification, and heat transfer. The efficiency of each process depends on the rate of droplet nucleation, droplet growth, and mass transfer. Unfortunately, hydrophilic surfaces are good at nucleation but poor at shedding. Hydrophobic surfaces are the reverse. Many plants and animals overcome this tradeoff through biphilic surfaces with patterned wettability. For example, the Stenocara beetle uses hydrophilic patches on a superhydrophobic background to collect fog from air. Cribellate spiders similarly collect fog on their webs through periodic spindle-knot structures. In this study, we investigate the effects of wettability patterns on the rate of water collection from humid air. The steady state rate of water collection per unit area is measured as a function of undercooling, angle of inclination, water contact angle, hydrophilic patch size, patch spacing, area fraction, and patch height relative to the hydrophobic background. We then model each pattern by comparing the potential and kinetic energy of a droplet as it rolls downwards at a fixed angle. The results indicate that the design rules for collecting fog differ from those for condensation from humid air. The authors gratefully acknowledge the Office of Naval Research for financial support through Grant Number N00014-15-1-2107.

  14. Equipment for Measuring Air Flow, Air Temperature, Relative Humidity, and Carbon Dioxide in Schools. Technical Bulletin.

    ERIC Educational Resources Information Center

    Jacobs, Bruce W.

    Information on equipment and techniques that school facility personnel may use to evaluate IAQ conditions are discussed. Focus is placed on the IAQ parameters of air flow, air temperature, relative humidity, as well as carbon dioxide and the equipment used to measure these factors. Reasons for measurement and for when the measurement of these…

  15. Relative Humidity and its Effect on Sampling and Analysis of Agricultural Odorants in Air

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Source and ambient air sampling techniques used in agricultural air quality studies are seldom validated for the variability in the air matrix (temperature, dust levels, and relative humidity). In particular, relative humidity (RH) affects both field sampling and analysis of air samples. The objec...

  16. D-Zero Instrument Air System Humidity Transmitter Evaluation

    SciTech Connect

    Serges, T.J.; /Fermilab

    1988-07-15

    This report shows the findings that resulted in the purchase of the optimum dew point hygrometer for use in the D-Zero instrument air system (see diagram 2 on page 9). The hygrometer will monitor the air syste m to insure that the dew point level does not go above the normal operating output of the driers (this precise value will be determined during initial system start-up). The following criteria was used in the evaluation: (1) Long term durability; (2) Minimum calibration; (3) Indicate a dew point level down to -40 C accurately; (4) Designed to work in a low humidity region; (5) Minimum maintenance; (6) Fast response time; and (7) Lowest cost provided all other criteria is met.

  17. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 34 2013-07-01 2013-07-01 false NOX intake-air humidity...

  18. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 33 2011-07-01 2011-07-01 false NOX intake-air humidity...

  19. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 32 2010-07-01 2010-07-01 false NOX intake-air humidity...

  20. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 34 2012-07-01 2012-07-01 false NOX intake-air humidity...

  1. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.670 NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you... 40 Protection of Environment 33 2014-07-01 2014-07-01 false NOX intake-air humidity...

  2. 40 CFR 1066.615 - NOX intake-air humidity correction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false NOX intake-air humidity correction. 1066.615 Section 1066.615 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Calculations § 1066.615 NOX intake-air humidity...

  3. Influence of humidity on the characteristics of negative corona discharge in air

    NASA Astrophysics Data System (ADS)

    Xu, Pengfei; Zhang, Bo; He, Jinliang; Chen, Shuiming

    2015-09-01

    Detailed negative corona discharge characteristics, such as the pulse amplitude, repetition frequency, average corona current, rise time, and half-wave time, are systematically studied under various air humidities with a single artificial defect electrode. The experimental result reveals that the pulse amplitude increases with the increase of air humidity; meanwhile, the repetition frequency deceases as the air humidity increases. Empirical formulae are first established for the pulse amplitude and repetition frequency with the humidity factor taken into consideration. The effective ionization integral is calculated and a positive correlation is found between the integral and the pulse amplitude. Furthermore, a simplified negative-ion cloud model is built up to investigate the mechanism of the humidity's influence on negative corona discharge. Based on the theoretical analyses, the correlation between pulse amplitude, repetition frequency, and air humidity is well explained.

  4. Influence of humidity on the characteristics of negative corona discharge in air

    SciTech Connect

    Xu, Pengfei Zhang, Bo He, Jinliang Chen, Shuiming

    2015-09-15

    Detailed negative corona discharge characteristics, such as the pulse amplitude, repetition frequency, average corona current, rise time, and half-wave time, are systematically studied under various air humidities with a single artificial defect electrode. The experimental result reveals that the pulse amplitude increases with the increase of air humidity; meanwhile, the repetition frequency deceases as the air humidity increases. Empirical formulae are first established for the pulse amplitude and repetition frequency with the humidity factor taken into consideration. The effective ionization integral is calculated and a positive correlation is found between the integral and the pulse amplitude. Furthermore, a simplified negative-ion cloud model is built up to investigate the mechanism of the humidity's influence on negative corona discharge. Based on the theoretical analyses, the correlation between pulse amplitude, repetition frequency, and air humidity is well explained.

  5. Improving Regional Air Quality with Wind Energy

    SciTech Connect

    Not Available

    2005-05-01

    This model documentation is designed to assist State and local governments in pursuing wind energy purchases as a control measure under regional air quality plans. It is intended to support efforts to draft State Implementation Plans (SIPs), including wind energy purchases, to ensure compliance with the standard for ground-level ozone established under the Clean Air Act.

  6. Modeling Validation and Control Analysis for Controlled Temperature and Humidity of Air Conditioning System

    PubMed Central

    Lee, Jing-Nang; Lin, Tsung-Min

    2014-01-01

    This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14°C, 0006 kgw/kgda in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system. PMID:25250390

  7. An ultrasonic air temperature measurement system with self-correction function for humidity

    NASA Astrophysics Data System (ADS)

    Tsai, Wen-Yuan; Chen, Hsin-Chieh; Liao, Teh-Lu

    2005-02-01

    This paper proposes an ultrasonic measurement system for air temperature with high accuracy and instant response. It can measure the average temperature of the environmental air by detecting the changes of the speed of the ultrasound in the air. The changes of speed of sound are computed from combining variations of time-of-flight (TOF) from a binary frequency shift-keyed (BFSK) ultrasonic signal and phase shift from continuous waves [11]. In addition, another proposed technique for the ultrasonic air temperature measurement is the self-correction functionality within a highly humid environment. It utilizes a relative humidity/water vapour sensor and applies the theory of how sound speed changes in a humid environment. The proposed new ultrasonic air temperature measurement has the capability of self-correction for the environment variable of humidity. Especially under the operational environment with high fluctuations of various humidity levels, the proposed system can accurately self-correct the errors on the conventional ultrasonic thermometer caused by the changing density of the vapours in the air. Including the high humidity effect, a proof-of-concept experiment demonstrates that in dry air (relative humidity, RH = 10%) without humidity correction, it is accurate to ±0.4 °C from 0 °C to 80 °C, while in highly humid air (relative humidity, RH = 90%) with self-correction functionality, it is accurate to ±0.3 °C from 0 °C to 80 °C with 0.05% resolution and temperature changes are instantly reflected within 100 ms.

  8. Influence of humidity on the characteristics of positive corona discharge in air

    NASA Astrophysics Data System (ADS)

    Xu, Pengfei; Zhang, Bo; Chen, Shuiming; He, Jinliang

    2016-06-01

    Detailed positive corona discharge characteristics, such as the corona onset voltage, pulse amplitude, repetition frequency, average corona current, rise time, and half-wave time, are systematically studied under different air humidity with a single artificial defect electrode. The experimental results indicate that the pulse amplitude decreases with the increase of air humidity; meanwhile, the repetition frequency increases as the air humidity increases. This phenomenon is different from that of negative corona discharge. Therefore, to have an insight into the mechanism of humidity influence on positive corona discharge, a positive corona discharge model based on the continuity equations is utilized. The simulations present a dynamic development of positive corona discharge and, meanwhile, reveal the humidity influence on positive corona discharge.

  9. Effect of production microclimate on female thermal state with increased temperature and air humidity

    NASA Technical Reports Server (NTRS)

    Machablishvili, O. G.

    1980-01-01

    The thermal state of women during the effect of high air temperature and relative humidity with a varying degree of physical loads was studied. Parameters for air temperature, relative humidity, and air movement were established. It was established that in women the thermo-regulatory stress occurs at lower air temperatures and with lower physical loads than in men. The accumulation of heat in women was revealed with lower air temperature than in men. It is concluded that to preserve the normal physiological state of the female organism it is necessary to create more favorable microclimate conditions and decrease the physical loads.

  10. Insect hygroreceptor responses to continuous changes in humidity and air pressure

    PubMed Central

    Tichy, H.; Kallina, W.

    2011-01-01

    The most favored model of humidity transduction views the cuticular wall of insect hygroreceptive sensilla as a hygromechanical transducer. Hygroscopic swelling or shrinking alters the geometry of the wall, deforming the dendritic membranes of the moist and dry cells. The small size the sensilla and their position surrounded by elevated structures creates technical difficulties to mechanically stimulate them by direct contact. The present study investigated hygroreceptors on the antennae of the cockroach and the stick insect. Accurately controlled, homogeneous mechanical input was delivered by modulating air pressure. Both the moist and dry cells responded not only to changes in air pressure, but also in the opposite direction, as observed during changes in air humidity. The moist-cell’s excitatory response to increasing humidity and increasing air pressure implies that swelling of the hygroscopic cuticle compresses the dendrites, and the dry-cell’s excitatory response to decreasing humidity and decreasing air pressure implies that shrinking of the hygroscopic cuticle expands the dendrites. The moist and dry cells of the stick insect are more sensitive to pressure changes than those of the cockroach, but the responses to air pressure are generally weaker than to humidity. Therefore, the hygroreceptive sensilla differ in their physical properties and constitutions. Furthermore, the mechanical parameters associated with homogeneous changes in air pressure on the sensillum surface can only partially account for the responses of the moist and dry cells of both species to humidity stimulation. PMID:20375249

  11. Insect hygroreceptor responses to continuous changes in humidity and air pressure.

    PubMed

    Tichy, H; Kallina, W

    2010-06-01

    The most favored model of humidity transduction views the cuticular wall of insect hygroreceptive sensilla as a hygromechanical transducer. Hygroscopic swelling or shrinking alters the geometry of the wall, deforming the dendritic membranes of the moist and dry cells. The small size the sensilla and their position surrounded by elevated structures creates technical difficulties to mechanically stimulate them by direct contact. The present study investigated hygroreceptors on the antennae of the cockroach and the stick insect. Accurately controlled, homogeneous mechanical input was delivered by modulating air pressure. Both the moist and dry cells responded not only to changes in air pressure but also in the opposite direction, as observed during changes in air humidity. The moist cell's excitatory response to increasing humidity and increasing air pressure implies that swelling of the hygroscopic cuticle compresses the dendrites, and the dry cell's excitatory response to decreasing humidity and decreasing air pressure implies that shrinking of the hygroscopic cuticle expands the dendrites. The moist and dry cells of the stick insect are more sensitive to pressure changes than those of the cockroach, but the responses to air pressure are generally weaker than to humidity. Therefore the hygroreceptive sensilla differ in their physical properties and constitutions. Furthermore, the mechanical parameters associated with homogeneous changes in air pressure on the sensillum surface can only partially account for the responses of the moist and dry cells of both species to humidity stimulation. PMID:20375249

  12. Simulating Tree and Topography Effects on Urban Air temperature and Humidity

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Endreny, T. A.; Nowak, D. J.; Kroll, C.; Heisler, G. M.

    2012-12-01

    Microclimate, especially air temperature and humidity, significantly affect human thermal comfort, ecosystem services, and building energy use. Air temperature and humidity measurements are generally recorded at fixed-location meteorology stations, which do not represent the spatial variations encountered in these parameters across the landscape. We developed a spatial air temperature and humidity model to simulate local air temperature and humidity over a region where the mesoscale climate is presumed homogeneous. The model assumes that under the same mesoscale climate, microclimate is modified by local topography and land cover, which are two critical factors determining the absorbed solar radiation and the partitioning of sensible and latent heat. Therefore, the difference in microclimates among local clusters can be determined by the differences in local topography and land cover. Given a reference site where the meteorological data are collected, the microclimate of any other local cluster can be obtained by comparing the topography and land cover of the reference site and the local cluster. The model was tested at 11 locations in Syracuse, NY, where the hourly air temperature and humidity were measured from July 15, 2010 through September 15, 2010. The simulation results showed the model has high efficiency in estimating local cluster air temperature and humidity. The model can be applied on strategic urban reforestation designs, urban heat island mitigation, climate change mitigation and adaptation, and ecosystem interaction research.

  13. 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

  14. Influence of Air Temperature and Humidity on Dehydration Equilibria and Kinetics of Theophylline

    PubMed Central

    Touil, Amira; Peczalski, Roman; Timoumi, Souad; Zagrouba, Fethi

    2013-01-01

    The effect of hygrothermal conditions (air temperature and relative humidity) on the dehydration of theophylline monohydrate was investigated. Firstly, the equilibrium states of theophylline were investigated. The data from gravimetric analysis at constant temperature and humidity were reported as desorption isotherms. The PXRD analysis was used to identify the different polymorphic forms of theophylline: the monohydrate, the metastable anhydrate, and the stable anhydrate. Solid-solid phase diagrams for two processing times were proposed. Secondly, the dehydration kinetics were studied. The water content evolutions with time were recorded at several temperatures from 20°C to 80°C and several relative humidities from 4% to 50%. Different mathematical models were used to fit the experimental data. The spatially averaged solution of 2D Fickian transient diffusion equation best represented the water mass loss versus time experimental relationship. The dehydration rate constant was found to increase exponentially with air temperature and to decrease exponentially with air relative humidity. PMID:26556000

  15. Influence of Air Temperature and Humidity on Dehydration Equilibria and Kinetics of Theophylline.

    PubMed

    Touil, Amira; Peczalski, Roman; Timoumi, Souad; Zagrouba, Fethi

    2013-01-01

    The effect of hygrothermal conditions (air temperature and relative humidity) on the dehydration of theophylline monohydrate was investigated. Firstly, the equilibrium states of theophylline were investigated. The data from gravimetric analysis at constant temperature and humidity were reported as desorption isotherms. The PXRD analysis was used to identify the different polymorphic forms of theophylline: the monohydrate, the metastable anhydrate, and the stable anhydrate. Solid-solid phase diagrams for two processing times were proposed. Secondly, the dehydration kinetics were studied. The water content evolutions with time were recorded at several temperatures from 20°C to 80°C and several relative humidities from 4% to 50%. Different mathematical models were used to fit the experimental data. The spatially averaged solution of 2D Fickian transient diffusion equation best represented the water mass loss versus time experimental relationship. The dehydration rate constant was found to increase exponentially with air temperature and to decrease exponentially with air relative humidity. PMID:26556000

  16. Correlation formulas for the frost thickness and heat transfer coefficient on a cylinder in humid air cross flow

    SciTech Connect

    Sengupta, S.; Sherif, S.A.; Wong, K.V.

    1995-12-31

    This paper reports on results of an experimental investigation where the emphasis was placed on obtaining empirical correlations for the frost thickness-time history and the heat transfer coefficient-time history for a cylinder in humid air cross flow. The facility employed for the investigation consisted of a low velocity wind tunnel comprised of a rectangular test section, a transition section and a honeycomb placed at the tunnel entrance. An external refrigerator was used to cool an antifreeze solution having a mixture of 90% methanol and 10% ethylene glycol. Measured parameters included, among other things, the heat transfer coefficient as well as the frost thickness.

  17. The impact of humidity on evaporative cooling in small desert birds exposed to high air temperatures.

    PubMed

    Gerson, Alexander R; Smith, Eric Krabbe; Smit, Ben; McKechnie, Andrew E; Wolf, Blair O

    2014-01-01

    Environmental temperatures that exceed body temperature (Tb) force endothermic animals to rely solely on evaporative cooling to dissipate heat. However, evaporative heat dissipation can be drastically reduced by environmental humidity, imposing a thermoregulatory challenge. The goal of this study was to investigate the effects of humidity on the thermoregulation of desert birds and to compare the sensitivity of cutaneous and respiratory evaporation to reduced vapor density gradients. Rates of evaporative water loss, metabolic rate, and Tb were measured in birds exposed to humidities ranging from ∼2 to 30 g H2O m(-3) (0%-100% relative humidity at 30°C) at air temperatures between 44° and 56°C. In sociable weavers, a species that dissipates heat primarily through panting, rates of evaporative water loss were inhibited by as much as 36% by high humidity at 48°C, and these birds showed a high degree of hyperthermia. At lower temperatures (40°-44°C), evaporative water loss was largely unaffected by humidity in this species. In Namaqua doves, which primarily use cutaneous evaporation, increasing humidity reduced rates of evaporative water loss, but overall rates of water loss were lower than those observed in sociable weavers. Our data suggest that cutaneous evaporation is more efficient than panting, requiring less water to maintain Tb at a given temperature, but panting appears less sensitive to humidity over the air temperature range investigated here. PMID:25461643

  18. Preliminary Investigations on the Effect of Humidity on the Reception of Visible Solar Radiation and the Effect of Humidity and Wind Speed on PV Module Output

    NASA Astrophysics Data System (ADS)

    Zainuddin, Hedzlin; Shaari, Sulaiman; Omar, Ahmad Maliki; Zain, Zainazlan Md.; Soumin, Jonson; Surat, Zainizam

    2010-07-01

    In order to improve the accuracy of methods currently used for characterizing the performance of photovoltaic (PV) arrays in their actual use environment, it is of importance to investigate the effect of ambient variables on the PV module output. Malaysia is a hot and humid country with relative humidity (RH) of 100% during rainfall and wind speed of greater than 4.0 ms-1 occurred about 8.4% in five years time. Therefore, the objective of this paper is to do a preliminary investigation on the effects of RH on the reception of solar radiation and the effect of humidity and wind speed on the PV module output. Outdoor field testing was conducted at Photovoltaic Monitoring Centre (PVMC), Universiti Teknologi MARA, of a BPSX-30U polycrystalline under variation of RH and wind speed separately. From the field testing, it was found that humidity reduced the amount of visible solar radiation reception, while humidity and wind speed both acts as cooling agents that increase the output of a PV module by reducing the module temperature.

  19. High-speed sterilization technique using dielectric barrier discharge plasmas in atmospheric humid air

    NASA Astrophysics Data System (ADS)

    Miyamae, M.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2010-11-01

    The inactivation of Bacillus atrophaeus spores by a dielectric barrier discharge (DBD) plasma produced by an ac voltage application of 1 kHz in atmospheric humid air was investigated in order to develop low-temperature, low-cost and high-speed plasma sterilization technique. The biological indicators covered with a Tyvek sheet were set just outside the DBD plasma region, where the air temperature and humidity as a discharge gas were precisely controlled by an environmental test chamber. The results show that the inactivation of Bacillus atrophaeus spores was found to be dependent strongly on the humidity, and was completed within 15 min at a relative humidity of 90 % and a temperature of 30 C. The treatment time for sterilization is shorter than those of conventional sterilization methods using ethylene oxide gas and dry heat treatment. It is considered that reactive species such as hydroxyl radicals that are effective for the inactivation of Bacillus atrophaeus spores could be produced by the DBD plasma in the humid air. Repetitive micro-pulsed discharge plasmas in the humid air will be applied for the sterilization experiment to enhance the sterilization efficiency.

  20. High accuracy acoustic relative humidity measurement in duct flow with air.

    PubMed

    van Schaik, Wilhelm; Grooten, Mart; Wernaart, Twan; van der Geld, Cees

    2010-01-01

    An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0-12 m/s with an error of ± 0.13 m/s, temperature 0-100 °C with an error of ± 0.07 °C and relative humidity 0-100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments. PMID:22163610

  1. High Accuracy Acoustic Relative Humidity Measurement in Duct Flow with Air

    PubMed Central

    van Schaik, Wilhelm; Grooten, Mart; Wernaart, Twan; van der Geld, Cees

    2010-01-01

    An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0–12 m/s with an error of ±0.13 m/s, temperature 0–100 °C with an error of ±0.07 °C and relative humidity 0–100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments. PMID:22163610

  2. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    NASA Technical Reports Server (NTRS)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    Air purification systems are necessary to provide clean air in the closed environments aboard spacecraft. Trace contaminants are removed using adsorption. One major factor concerning the removal of trace contaminants is relative humidity. Water can reduce adsorption capacity and, due to constant fluctuations, its presence is difficult to incorporate into adsorption column designs. The purpose of the research was to allow for better design techniques in trace contaminant adsorption systems, especially for feeds with water present. Experiments and mathematical modeling research on effects of humidity swings on adsorption columns for air revitalization were carried out.

  3. Temperature and Humidity Independent Control Research on Ground Source Heat Pump Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Chen, G.; Wang, L. L.

    Taking green demonstration center building air conditioning system as an example, this paper presents the temperature and humidity independent control system combined with ground source heat pump system, emphasis on the design of dry terminal device system, fresh air system and ground source heat pump system.

  4. Hydrochloric acid aerosol formation by the interaction of hydrogen chloride with humid air

    NASA Technical Reports Server (NTRS)

    Rhein, R. A.

    1973-01-01

    The conditions in which hydrochloric acid aerosol is predicted by the interaction of hydrogen chloride gas with the water vapor in humid air are analyzed. The liquid gas phase equilibrium for the HCL-H2O system is expressed in terms of relative humidity and hydrogen chloride concentration as parts per million, units commonly used in pollution studies. Presented are the concentration (wt %) of HC1 in the aerosol and the concentration of aerosol (ppm) predicted.

  5. Measurement of the radon diffusion through a nylon foil for different air humidities

    SciTech Connect

    Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

    2015-08-17

    The dependency of the radon penetration through a nylon foil on air humidity was measured. Such information is needed for the tracking part of the SuperNEMO detector, which is planned to be shielded against radon by nylon foil and in which the air humidity is not negligible. The long term measurements of radon penetration through nylon foils for different air humidities were performed with the radon diffusion setup constructed at the IEAP, CTU in Prague. The setup consists of two stainless steel hemispheres with Si detector in each of them. Both hemispheres are separated by the tested foil. While the left hemisphere contains high Rn activity, the right part contains only activity caused by the radon penetration through the tested foil. Obtained results of this study with a nylon foil with the thickness of 50 µm are presented.

  6. Measurement of the radon diffusion through a nylon foil for different air humidities

    NASA Astrophysics Data System (ADS)

    Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

    2015-08-01

    The dependency of the radon penetration through a nylon foil on air humidity was measured. Such information is needed for the tracking part of the SuperNEMO detector, which is planned to be shielded against radon by nylon foil and in which the air humidity is not negligible. The long term measurements of radon penetration through nylon foils for different air humidities were performed with the radon diffusion setup constructed at the IEAP, CTU in Prague. The setup consists of two stainless steel hemispheres with Si detector in each of them. Both hemispheres are separated by the tested foil. While the left hemisphere contains high Rn activity, the right part contains only activity caused by the radon penetration through the tested foil. Obtained results of this study with a nylon foil with the thickness of 50 µm are presented.

  7. DYNAMICS of optical-microphysical properties of atmospheric haze at stepwise change of air humidity

    NASA Astrophysics Data System (ADS)

    Rakhimov, Rustam F.; Kozlov, Valerii S.; Shmargunov, Vladimir P.

    2015-11-01

    The three-day cycle of spectronephelometric measurements of the angular aerosol scattering coefficients of the near-ground aerosol at the stepwise increase/decrease of the relative air humidity of 50, 65, 75, 85, and 90% has been conducted in the Large Aerosol Chamber of IAO SB RAS filled with the atmospheric air. The results of solution of the inverse problem have shown that the condensation coarsening of particles at the simultaneous decrease of their refractive index and the imaginary part of the complex refraction index (absorption index) is stably observed with an increase of the relative air humidity for ultrafine (with radii of 30-100 nm) and fine (100-370 nm) particles. However, for the coarse particles (370-600 nm), the increase of humidity leads to the effect of increase of the refractive index from 1.60 to 1.66, while the values of the absorption index are low (˜10-5) and vary only slightly at the aerosol humidification. The effective radius of particles (165-195 nm) and the single scattering albedo (0.71-0.83) increase synchronously with an increase of the air humidity. For two days of aerosol evolution in the closed volume of the chamber, the total extinction and absorption coefficients also vary synchronously with the variation of humidity, but at the third day the influence of humidity on the absorption coefficient was not observed. A possible reason for appearance of specific condensation peculiarities is the influence of humidity variations on the inflow/outflow of particles smaller than 30 nm and larger than 600 nm having various physical-chemical composition into the optically active size range.

  8. Calculating osmotic pressure of xylitol solutions from molality according to UNIFAC model and measuring it with air humidity osmometry.

    PubMed

    Yu, Lan; Zhan, Tingting; Zhan, Xiancheng; Wei, Guocui; Tan, Xiaoying; Wang, Xiaolan; Li, Chengrong

    2014-11-01

    The osmotic pressure of xylitol solution at a wide concentration range was calculated according to the UNIFAC model and experimentally determined by our newly reported air humidity osmometry. The measurements from air humidity osmometry were compared with UNIFAC model calculations from dilute to saturated solution. Results indicate that air humidity osmometry measurements are comparable to UNIFAC model calculations at a wide concentration range by two one-sided test and multiple testing corrections. The air humidity osmometry is applicable to measure the osmotic pressure and the osmotic pressure can be calculated from the concentration. PMID:24032449

  9. The sensitivity of latent heat flux to the air humidity approximations used in ocean circulation models

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Niiler, Pearn P.

    1990-01-01

    In deriving the surface latent heat flux with the bulk formula for the thermal forcing of some ocean circulation models, two approximations are commonly made to bypass the use of atmospheric humidity in the formula. The first assumes a constant relative humidity, and the second supposes that the sea-air humidity difference varies linearly with the saturation humidity at sea surface temperature. Using climatological fields derived from the Marine Deck and long time series from ocean weather stations, the errors introduced by these two assumptions are examined. It is shown that the errors reach above 100 W/sq m over western boundary currents and 50 W/sq m over the tropical ocean. The two approximations also introduce erroneous seasonal and spatial variabilities with magnitudes over 50 percent of the observed variabilities.

  10. Airborne pollen sampling in Manoa Valley, Hawaii: effect of rain, humidity and wind.

    PubMed

    Massey, D G; Fournier-Massey, G

    1984-05-01

    Kramer-Collins pollen sampling was conducted over 24 hours for 25 consecutive months at two valley sites in Honolulu. Of 1,059 expected samples, 699 (66.0%) were collected. Only 25 were considered excellent, i.e., eight three-hour collection bands. Twenty eight were considered good, ie., two to six bands. The difficulties in the study were associated with the weather directly (17.5%), the power source (3.9%), inadequancy of the samplers (63.1%) and the inexperience of technicians (15.3%). Sampler problems were also indirectly attributable to the high humidity, rain and wind, which differed at the two sites. PMID:6721258

  11. Preventing Indoor Air Quality Problems in Educational Facilities: Guidelines for Hot, Humid Climates. Revised.

    ERIC Educational Resources Information Center

    Odom, J. David; DuBose, George

    This manual addresses the errors that occur during new construction that subsequently contribute to indoor air quality (IAQ) problems in newly constructed buildings in hot and humid climates, and offers guidelines for preventing them during the design and construction phases. It defines the roles and responsibilities of the design team, the…

  12. STS-32 OV-102 air revitalization system (ARS) humidity separator problem

    NASA Technical Reports Server (NTRS)

    1990-01-01

    During STS-32, onboard Columbia, Orbiter Vehicle (OV) 102, a leakage problem at environmental control and life support system (ECLSS) air revitalization system (ARS) humidity separator A below the middeck is solved with a plastic bag and a towel. The towel inserted inside a plastic bag absorbed the water that had collected at the separator inlet.

  13. 6. VIEW OF FIVEFOOT WIND TUNNEL WITH AIR STRAIGHTENER AND ...

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

    6. VIEW OF FIVE-FOOT WIND TUNNEL WITH AIR STRAIGHTENER AND OPERATOR STATION IN FOREGROUND (1991). - Wright-Patterson Air Force Base, Area B, Building No. 19, Five-Foot Wind Tunnel, Dayton, Montgomery County, OH

  14. Storage corrosion of materials and equipment: Temperature-humidity and aerochemical regimes indoors and in the open air

    SciTech Connect

    Strekalov, P.V.

    1994-07-01

    The following storage factors are considered: (1) the temperature-humidity complex (THC) in the open air at representative sites with cold, moderate, and subtropical humid climate; (2) the temperature and humidity differences between the open air and an atmospheric of semiclosed spaces; (3) the THC inside storage-spaces in a humid tropical climate; (4) the concentration of SO{sub 2} and Cl{sup -} in the open air and in different storage-spaces; (5) the categories of corrosivity of the atmosphere and methods for its evaluation indoors and outdoors.

  15. Effect of inlet-air humidity on the formation of oxides of nitrogen in a gas-turbine combustor

    NASA Technical Reports Server (NTRS)

    Marchionna, N. R.

    1973-01-01

    Tests were conducted to determine the effect of inlet-air humidity on the formation of oxides of nitrogen from a gas-turbine combustor. Combustor inlet-air temperature ranged from 450 F to 1050 F. The tests were run at a constant pressure of 6 atmospheres and reference Mach number of 0.065. The NO sub x emission index was found to decrease with increasing inlet-air humidity at a constant exponential rate of 19 percent per mass percent water vapor in the air. This decrease of NO sub x emission index with increasing humidity was found to be independent of inlet-air temperature.

  16. Sterilization of soybean powder with plasma treatment in atmospheric humid air

    NASA Astrophysics Data System (ADS)

    Iwami, R.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.; Nakayama, A.; Nakagawa, K.

    2013-10-01

    Sterilization of foods has been performed by conventional methods such as heat, steam and chemical solutions. However, these sterilization techniques could cause damages to the food material. It is considered that plasma sterilization at atmospheric pressure is one of the promising alternative methods because of the low temperature process. In our previous study, the inactivation of Bacillus atrophaeusspores by a dielectric barrier discharge (DBD) plasma produced in atmospheric humid air was investigated in order to develop low-temperature, low-cost and high-speed plasma sterilization technique. The results showed that the inactivation of Bacillus atrophaeusspores was found to be dependent strongly on the humidity. In the present study, the plasma treatment technique in humid air is applied to sterilization of soybean powder. Effects of plasma sterilization were successfully confirmed by a colony counting method. It was found that the sterilization efficiency was increased by using the humid air as the discharge gas. In the conference, an improvement of the plasma treatment system to enhance the sterilization efficiency will be shown.

  17. Electro-Hydrodynamics and Kinetic Modeling of Dry and Humid Air Flows Activated by Corona Discharges

    NASA Astrophysics Data System (ADS)

    P. Sarrette, J.; Eichwald, O.; Marchal, F.; Ducasse, O.; Yousfi, M.

    2016-05-01

    The present work is devoted to the 2D simulation of a point-to-plane Atmospheric Corona Discharge Reactor (ACDR) powered by a DC high voltage supply. The corona reactor is periodically crossed by thin mono filamentary streamers with a natural repetition frequency of some tens of kHz. The study compares the results obtained in dry air and in air mixed with a small amount of water vapour (humid air). The simulation involves the electro-dynamics, chemical kinetics and neutral gas hydrodynamics phenomena that influence the kinetics of the chemical species transformation. Each discharge lasts about one hundred of a nanosecond while the post-discharge occurring between two successive discharges lasts one hundred of a microsecond. The ACDR is crossed by a lateral dry or humid air flow initially polluted with 400 ppm of NO. After 5 ms, the time corresponding to the occurrence of 50 successive discharge/post-discharge phases, a higher NO removal rate and a lower ozone production rate are found in humid air. This change is due to the presence of the HO2 species formed from the H primary radical in the discharge zone.

  18. Multiscale Covariability of Surface Wind, Humidity and Temperature in the Subtropical Marine Boundary Layer

    NASA Astrophysics Data System (ADS)

    Fildier, Benjamin; Collins, William

    2016-04-01

    Trade cumulus and stratocumulus clouds in oceanic subtropical regions are sources of much uncertainty in current global climate model (GCM) simulations. Errors in low cloud fraction and rain amounts are a result of inadequate parameterizations for describing the small-scale boundary layer processes specific to the convective and cloud-formation dynamics of those regions. While most cloud parameterization techniques do consider sub-grid scale variability in specific humidity (q), the significant fluctuations in temperature (T) and wind speed (u) in the boundary layer are still often neglected. In order to better acknowledge the interactions of these fields with cloud and convection, understanding their codependence seems crucial. For example, using the negative correlations between T and q on large scales has helped to improve cloud parameterizations, and wind shear is known to modulate cloud layer decoupling and affect the liquid water path (LWP). While numerous studies document the spatial properties of T , q and u independently through power spectra and multifractal analyses, the covariation between these three variables and their spatial increments - and how these relationships change across spatial scales - has not been adequately and quantitatively characterized. The present work focuses on the spatial covariability and multiscale coupling between fluctuations in q, T and u in the marine boundary layer and seeks to understand which pieces of information are required for better predicting LWP on a variety of scales from a few tens to a few hundred kms. We use remote-sensing measurements of thermodynamic variables from MODIS and surface wind estimates from QuikSCAT. The scale-by-scale covariability of two variables is quantified through their Fourier and wavelet cross spectra, using Haar wavelets; these spectra permit the calculation of multiscale coupling exponents when appropriate. Results from this study are threefold: (1) we quantify the contributions of

  19. Humidity and aggregate content correction factors for air-coupled ultrasonic evaluation of concrete.

    PubMed

    Berriman, J; Purnell, P; Hutchins, D A; Neild, A

    2005-02-01

    This paper describes the use of non-contact ultrasound for the evaluation of concrete. Micromachined capacitance transducers are used to transmit ultrasonic longitudinal chirp signals through concrete samples using air as the coupling medium, and a pulse compression technique is then employed for measurement of time of flight through the sample. The effect on the ultrasonic wave speed of storing concrete samples, made with the same water/cement ratio, at different humidity levels is investigated. It is shown that there is a correlation between humidity and speed of sound, allowing a correction factor for humidity to be derived. A strong positive linear correlation between aggregate content and speed of sound was then observed; there was no obvious correlation between compressive strength and speed of sound. The results from the non-contact system are compared with that from a contact system, and conclusions drawn concerning coupling of energy into the samples. PMID:15567195

  20. The effect of increased air humidity on northern deciduous forest ecosystem - a FAHM study.

    NASA Astrophysics Data System (ADS)

    Ostonen, Ivika; Rosenvald, Katrin; Tullus, Arvo; Parts, Kaarin; Sellin, Arne; Kupper, Priit; Sõber, Jaak; Sõber, Anu; Uri, Veiko; Aosaar, Jürgen; Varik, Mats; Lõhmus, Krista

    2013-04-01

    At northern latitudes a rise in atmospheric humidity and precipitation is predicted as a consequence of global climate change. In 2006 an unique experimental facility for free air humidity manipulation (FAHM) was established in Estonia to study the functioning of deciduous forest ecosystem under altered humidity conditions. The experimental site contains humidified and control plots, each includes four types of forest ecosystem: two overstorey species (planted hybrid aspen (Populus tremula L. × P. tremuloides Michx. and silver birch (Betula pendula Roth.)) both split into two types according to understorey vegetation (diverse "forest" understory and early successional grasses). We investigated the productivity, biomass allocation and functioning of silver birch forest ecosystem in response to elevated atmospheric humidity (on average 7% over the ambient level) during four growing seasons (2008-2011). We hypothesized that elevated air humidity facilitates both above- and below-ground growth and accumulation of plant biomass. During the first three experimental seasons height, stem diameter, and stem volume (D2H) increments of trees, biomass of understory in aboveground and fine root biomass in belowground were similar or significantly reduced in humidified plots. Only the fine root and rhizome biomass of the understory was twice higher in humidified plots. However, fine root turnover speeded up for both tree and understory roots. The trends in above-ground growth changed in 2011, when current annual increments of trees height, diameter, stem volume and fine root biomass were higher in humidified plots. Functionally, trees hydraulic conductance was significantly higher and stem sap flux lower for humidified trees coinciding with significantly higher biomass of primary (in majority ectomycorrhizal) roots, morphologically thinner and longer root tips and higher specific root length. Humidification caused a shift in the root tips colonizing fungal community towards the

  1. Effect of humidity on the adsorption kinetics of lung surfactant at air-water interfaces.

    PubMed

    Zuo, Yi Y; Gitiafroz, Roya; Acosta, Edgar; Policova, Zdenka; Cox, Peter N; Hair, Michael L; Neumann, A Wilhelm

    2005-11-01

    The in vitro adsorption kinetics of lung surfactant at air-water interfaces is affected by both the composition of the surfactant preparations and the conditions under which the assessment is conducted. Relevant experimental conditions are surfactant concentration, temperature, subphase pH, electrolyte concentration, humidity, and gas composition of the atmosphere exposed to the interface. The effect of humidity on the adsorption kinetics of a therapeutic lung surfactant preparation, bovine lipid extract surfactant (BLES), was studied by measuring the dynamic surface tension (DST). Axisymmetric drop shape analysis (ADSA) was used in conjunction with three different experimental methodologies, i.e., captive bubble (CB), pendant drop (PD), and constrained sessile drop (CSD), to measure the DST. The experimental results obtained from these three methodologies show that for 100% relative humidity (RH) at 37 degrees C the rate of adsorption of BLES at an air-water interface is substantially slower than for low humidity. It is also found that there is a difference in the rate of surface tension decrease measured from the PD and CB/CSD methods. These experimental results agree well with an adsorption model that considers the combined effects of entropic force, electrostatic interaction, and gravity. These findings have implications for the development and evaluation of new formulations for surfactant replacement therapy. PMID:16262325

  2. Megha-Tropiques/SAPHIR measurements of humidity profiles: validation with AIRS and global radiosonde network

    NASA Astrophysics Data System (ADS)

    Subrahmanyam, K. V.; Kumar, K. K.

    2013-12-01

    The vertical profiles of humidity measured by SAPHIR (Sondeur Atmospherique du Profil d' Humidité Intropicale par Radiométrie) on-board Megha-Tropiques satellite are validated using Atmosphere Infrared Sounder (AIRS) and ground based radiosonde observations during July-September 2012. SAPHIR provides humidity profiles at six pressure layers viz., 1000-850 (level 1), 850-700 (level 2), 700-550 (level 3), 550-400 (level 4) 400-250 (level 5) and 250-100(level 6) hPa. Segregated AIRS observations over land and oceanic regions are used to assess the performance of SAPHIR quantitatively. The regression analysis over oceanic region (125° W-180° W; 30° S-30° N) reveal that the SAPHIR measurements agrees very well with the AIRS measurements at levels 3, 4, 5 and 6 with correlation coefficients 0.79, 0.88, 0.87 and 0.78 respectively. However, at level 6 SAPHIR seems to be systematically underestimating the AIRS measurements. At level 2, the agreement is reasonably good with correlation coefficient of 0.52 and at level 1 the agreement is very poor with correlation coefficient 0.17. The regression analysis over land region (10° W-30° E; 8° N-30° N) revealed an excellent correlation between AIRS and SAPHIR at all the six levels with 0.80, 0.78, 0.84, 0.84, 0.86 and 0.65 respectively. However, again at levels 5 and 6, SAPHIR seems to be underestimating the AIRS measurements. After carrying out the quantitative comparison between SAPHIR and AIRS separately over land and ocean, the ground based global radiosonde network observations of humidity profiles over three distinct geographical locations (East Asia, tropical belt of South and North America and South Pacific) are then used to further validate the SAPHIR observations as AIRS has its own limitations. The SAPHIR observations within a radius of 50 km around the radiosonde stations are averaged and then the regression analysis is carried out at the first five levels of SAPHIR. The comparison is not carried out at sixth

  3. Average Tropical Relative Humidity from AIRS, Dec-Feb 2002-2005

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The average tropospheric relative humidity from AIRS for the four December-February periods during 2002 through 2005.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  4. STS-32 OV-102 air revitalization system (ARS) humidity separator problem

    NASA Technical Reports Server (NTRS)

    1990-01-01

    During STS-32, onboard Columbia, Orbiter Vehicle (OV) 102, a leakage problem at environmental control and life support system (ECLSS) air revitalization system (ARS) humidity separator A below the middeck is documented in this closeup view. Note the many bubbles around the separator. The crew cleared out stowage bags, lithium hydroxide (LiOH) cannisters and other materials to get at the problem. It was eventually repaired.

  5. Investigation on wind energy-compressed air power system.

    PubMed

    Jia, Guang-Zheng; Wang, Xuan-Yin; Wu, Gen-Mao

    2004-03-01

    Wind energy is a pollution free and renewable resource widely distributed over China. Aimed at protecting the environment and enlarging application of wind energy, a new approach to application of wind energy by using compressed air power to some extent instead of electricity put forward. This includes: explaining the working principles and characteristics of the wind energy-compressed air power system; discussing the compatibility of wind energy and compressor capacity; presenting the theoretical model and computational simulation of the system. The obtained compressor capacity vs wind power relationship in certain wind velocity range can be helpful in the designing of the wind power-compressed air system. Results of investigations on the application of high-pressure compressed air for pressure reduction led to conclusion that pressure reduction with expander is better than the throttle regulator in energy saving. PMID:14727304

  6. Efficient and stable perovskite solar cells prepared in ambient air irrespective of the humidity.

    PubMed

    Tai, Qidong; You, Peng; Sang, Hongqian; Liu, Zhike; Hu, Chenglong; Chan, Helen L W; Yan, Feng

    2016-01-01

    Poor stability of organic-inorganic halide perovskite materials in humid condition has hindered the success of perovskite solar cells in real applications since controlled atmosphere is required for device fabrication and operation, and there is a lack of effective solutions to this problem until now. Here we report the use of lead (II) thiocyanate (Pb(SCN)2) precursor in preparing perovskite solar cells in ambient air. High-quality CH3NH3PbI3-x(SCN)x perovskite films can be readily prepared even when the relative humidity exceeds 70%. Under optimized processing conditions, we obtain devices with an average power conversion efficiency of 13.49% and the maximum efficiency over 15%. In comparison with typical CH3NH3PbI3-based devices, these solar cells without encapsulation show greatly improved stability in humid air, which is attributed to the incorporation of thiocyanate ions in the crystal lattice. The findings pave a way for realizing efficient and stable perovskite solar cells in ambient atmosphere. PMID:27033249

  7. Efficient and stable perovskite solar cells prepared in ambient air irrespective of the humidity

    NASA Astrophysics Data System (ADS)

    Tai, Qidong; You, Peng; Sang, Hongqian; Liu, Zhike; Hu, Chenglong; Chan, Helen L. W.; Yan, Feng

    2016-04-01

    Poor stability of organic-inorganic halide perovskite materials in humid condition has hindered the success of perovskite solar cells in real applications since controlled atmosphere is required for device fabrication and operation, and there is a lack of effective solutions to this problem until now. Here we report the use of lead (II) thiocyanate (Pb(SCN)2) precursor in preparing perovskite solar cells in ambient air. High-quality CH3NH3PbI3-x(SCN)x perovskite films can be readily prepared even when the relative humidity exceeds 70%. Under optimized processing conditions, we obtain devices with an average power conversion efficiency of 13.49% and the maximum efficiency over 15%. In comparison with typical CH3NH3PbI3-based devices, these solar cells without encapsulation show greatly improved stability in humid air, which is attributed to the incorporation of thiocyanate ions in the crystal lattice. The findings pave a way for realizing efficient and stable perovskite solar cells in ambient atmosphere.

  8. Efficient and stable perovskite solar cells prepared in ambient air irrespective of the humidity

    PubMed Central

    Tai, Qidong; You, Peng; Sang, Hongqian; Liu, Zhike; Hu, Chenglong; Chan, Helen L. W.; Yan, Feng

    2016-01-01

    Poor stability of organic–inorganic halide perovskite materials in humid condition has hindered the success of perovskite solar cells in real applications since controlled atmosphere is required for device fabrication and operation, and there is a lack of effective solutions to this problem until now. Here we report the use of lead (II) thiocyanate (Pb(SCN)2) precursor in preparing perovskite solar cells in ambient air. High-quality CH3NH3PbI3−x(SCN)x perovskite films can be readily prepared even when the relative humidity exceeds 70%. Under optimized processing conditions, we obtain devices with an average power conversion efficiency of 13.49% and the maximum efficiency over 15%. In comparison with typical CH3NH3PbI3-based devices, these solar cells without encapsulation show greatly improved stability in humid air, which is attributed to the incorporation of thiocyanate ions in the crystal lattice. The findings pave a way for realizing efficient and stable perovskite solar cells in ambient atmosphere. PMID:27033249

  9. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blakenship, Clay; Zavodsky, Bradley; Blackwell, William

    2014-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. Forecasts are against ERA reanalyses.

  10. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay; Zavodsky, Brad; Blackwell, William

    2014-01-01

    Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. This paper will describe the bias correction technique and results from forecasts evaluated by validation against a Total Precipitable Water (TPW) product from CIRA and against Global Forecast System (GFS) analyses.

  11. 20th Century Reanalysis Project Ensemble Gateway: 56 Estimates of World Temperature, Pressure, Humidity, and Wind, 1871-2010

    DOE Data Explorer

    This site provides data from the 20th Century Reanalysis Project, offering temperature, pressure, humidity, and wind predictions in 200 km sections all around the earth from 1871 to 2010, every 6 hours, based on historical data. The ensemble mean and standard deviation for each value were calculated over a set of 56 simulations. Data for each of the 56 ensemble members are included here. The dataset consists of files in netCDF 4 format that are available for download from the National Energy Research. The goal of the 20th Century Reanalysis Project is to use a Kalman filter-based technique to produce a global trophospheric circulation dataset at four-times-daily resolution back to 1871. The only dataset available for the early 20th century consists of error-ridden hand-drawn analyses of the mean sea level pressure field over the Northern Hemisphere. Modern data assimilation systems have the potential to improve upon these maps, but prior to 1948, few digitized upper-air sounding observations are available for such a reanalysis. The global tropospheric circulation dataset will provide an important validation check on the climate models used to make 21st century climate projections....[copied from http://portal.nersc.gov/project/20C_Reanalysis/

  12. A Humidity Control System with an Adsorption Material and Indoor Air Quality Improvement

    NASA Astrophysics Data System (ADS)

    Moriya, Yoshifumi; Ishii, Noriaki

    The present study introduces a humidity control apparatus which can hygienically and automatically maintain the appropriate humidity level of indoor air without either a water supply or drainage system. In humidification, the desiccant takes up water vapor from the outdoor air in the adsorption process, and release it indoors by desorption. Therefore, no water supply is required to humidify. An apparatus having no water supply is more hygienic, because it does not propagate bacteria and does not scatter the calcium and magnesium salts found in the water. In dehumidification, water vapor is removed from the indoor air by the desiccant and is released outdoors by desorption, eliminating the need for a drainage system. The absence of a drainage system also eliminates problems such as water leakage and installation. The performance of a system based on this new method was compared with that of conventional products, whereby the modes of dehumidification, humidification and humidification with ventilation were evaluated. In addition, the new system was tested to reveal the time-dependent charaeteristics of the concentration of indoor odor and the dust collection efficiency.

  13. Afterglow chemistry of atmospheric-pressure helium-oxygen plasmas with humid air impurity

    NASA Astrophysics Data System (ADS)

    Murakami, Tomoyuki; Niemi, Kari; Gans, Timo; O'Connell, Deborah; Graham, William G.

    2014-04-01

    The formation of reactive species in the afterglow of a radio-frequency-driven atmospheric-pressure plasma in a fixed helium-oxygen feed gas mixture (He+0.5%O2) with humid air impurity (a few hundred ppm) is investigated by means of an extensive global plasma chemical kinetics model. As an original objective, we explore the effects of humid air impurity on the biologically relevant reactive species in an oxygen-dependent system. After a few milliseconds in the afterglow environment, the densities of atomic oxygen (O) decreases from 1015 to 1013 cm-3 and singlet delta molecular oxygen (O2(1D)) of the order of 1015 cm-3 decreases by a factor of two, while the ozone (O3) density increases from 1014 to 1015 cm-3. Electrons and oxygen ionic species, initially of the order of 1011 cm-3, recombine much faster on the time scale of some microseconds. The formation of atomic hydrogen (H), hydroxyl radical (OH), hydroperoxyl (HO2), hydrogen peroxide (H2O2), nitric oxide (NO) and nitric acid (HNO3) resulting from the humid air impurity as well as the influence on the afterglow chemistry is clarified with particular emphasis on the formation of dominant reactive oxygen species (ROS). The model suggests that the reactive species predominantly formed in the afterglow are major ROS O2(1D) and O3 (of the order of 1015 cm-3) and rather minor hydrogen- and nitrogen-based reactive species OH, H2O2, HNO3 and NO2/NO3, of which densities are comparable to the O-atom density (of the order of 1013 cm-3). Furthermore, the model quantitatively reproduces the experimental results of independent O and O3 density measurements.

  14. Recent improvements in retrieving near-surface air temperature and humidity using microwave remote sensing (Invited)

    NASA Astrophysics Data System (ADS)

    Roberts, J. B.

    2010-12-01

    Detailed studies of the energy and water cycles require accurate estimation of the turbulent fluxes of moisture and heat across the atmosphere-ocean interface at regional to basin scale. Providing estimates of these latent and sensible heat fluxes over the global ocean necessitates the use of satellite or reanalysis-based estimates of near surface variables. Recent studies have shown that errors in the surface (10 meter) estimates of humidity and temperature are currently the largest sources of uncertainty in the production of turbulent fluxes from satellite observations. Therefore, emphasis has been placed on reducing the systematic errors in the retrieval of these parameters from microwave radiometers. This study discusses recent improvements in the retrieval of air temperature and humidity through improvements in the choice of algorithms (linear vs. nonlinear) and the choice of microwave sensors. Particular focus is placed on improvements using a neural network approach with a single sensor (Special Sensor Microwave/Imager) and the use of combined sensors from the NASA AQUA satellite platform. The latter algorithm utilizes the unique sampling available on AQUA from the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit (AMSU-A). Current estimates of uncertainty in the near-surface humidity and temperature from single and multi-sensor approaches are discussed and used to estimate errors in the turbulent fluxes.

  15. Recent Improvements in Retrieving Near-Surface Air Temperature and Humidity Using Microwave Remote Sensing

    NASA Technical Reports Server (NTRS)

    Roberts, J. Brent

    2010-01-01

    Detailed studies of the energy and water cycles require accurate estimation of the turbulent fluxes of moisture and heat across the atmosphere-ocean interface at regional to basin scale. Providing estimates of these latent and sensible heat fluxes over the global ocean necessitates the use of satellite or reanalysis-based estimates of near surface variables. Recent studies have shown that errors in the surface (10 meter)estimates of humidity and temperature are currently the largest sources of uncertainty in the production of turbulent fluxes from satellite observations. Therefore, emphasis has been placed on reducing the systematic errors in the retrieval of these parameters from microwave radiometers. This study discusses recent improvements in the retrieval of air temperature and humidity through improvements in the choice of algorithms (linear vs. nonlinear) and the choice of microwave sensors. Particular focus is placed on improvements using a neural network approach with a single sensor (Special Sensor Microwave/Imager) and the use of combined sensors from the NASA AQUA satellite platform. The latter algorithm utilizes the unique sampling available on AQUA from the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit (AMSU-A). Current estimates of uncertainty in the near-surface humidity and temperature from single and multi-sensor approaches are discussed and used to estimate errors in the turbulent fluxes.

  16. Air Pressure, Humidity and Stroke Occurrence: A Systematic Review and Meta-Analysis

    PubMed Central

    Cao, Yongjun; Wang, Xia; Zheng, Danni; Robinson, Thompson; Hong, Daqing; Richtering, Sarah; Leong, Tzen Hugh; Salam, Abdul; Anderson, Craig; Hackett, Maree L.

    2016-01-01

    Background/Aims: An influence of climate upon stroke risk is biologically plausible and supported by epidemiological evidence. We aimed to determine whether air pressure (AP) and humidity are associated with hospital stroke admission. Methods: We searched MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and GEOBASE, from inception to 16 October 2015 to identify relevant population-based observational studies. Where possible, data were pooled for meta-analysis with odds ratios (OR) and corresponding 95% confidence intervals (CI) by means of the random-effect method. Results: We included 11 studies with a total of 314,385 patients. The effect of AP was varied across studies for ischemic stroke (IS) and subarachnoid haemorrhage (SAH). Pooled ORs (95%CI) associated with 1 hPa increase in AP for the risk of IS, intracerebral hemorrhage (ICH) and SAH were 1.00 (0.99–1.01), 1.01 (0.99–1.02) and 1.02 (0.97–1.07) respectively. The pooled ORs (95%CI) associated with 1 percent increase in humidity for the risk of IS and ICH were 1.00 (1.00–1.01) and 1.00 (0.99–1.01) respectively. Conclusion: This review shows that there is no evidence of a relationship between AP or humidity and the occurrence of hospital admission for stroke. Further research is needed to clarify the extent and nature of any relationship between AP, humidity and stroke in different geographical areas. PMID:27399733

  17. One-dimensional variational (1D-Var) retrieval of middle to upper tropospheric humidity using AIRS radiance data

    NASA Astrophysics Data System (ADS)

    Ishimoto, Hiroshi; Okamoto, Kozo; Okamoto, Hajime; Sato, Kaori

    2014-06-01

    A one-dimensional variational analysis (1D-Var retrieval) of tropospheric humidity was conducted using hyper-spectral radiance data from the Atmospheric Infrared Sounder (AIRS). For the vertical range of the atmosphere between 200 and 600 hPa, the same high-resolution retrieval of humidity profiles as for clear-sky conditions was possible over low clouds if the cloud height was lower than 800 hPa. Global analyses from a global data assimilation system were used for initial profiles, and clear conditions over 800 hPa height were determined from AIRS radiance data. Results of analyses for 50 days of global radiosonde matchup data from 21 December 2008 to 8 February 2009 revealed that our 1D-Var calculations derived humidity profiles were closer to the sonde profiles than those of a global analysis at a height over 600 hPa. Furthermore, the results of 1D-Var retrieval often represented high and supersaturated relative humidity around the supposed ice clouds. The altitudes of the high humidity region agreed with the height of ice clouds that had been detected by CloudSat/CALIPSO. As well as possibly improving the humidity profiles in a numerical model by data assimilation, it is expected that these humidity analyses using AIRS radiance data will provide additional information for the study of ice clouds in the middle to upper troposphere.

  18. Effect of air temperature and humidity on ingestive behaviour of sheep

    NASA Astrophysics Data System (ADS)

    Paranhos da Costa, Mateus J. R.; da Silva, Roberto Gomes; de Souza, Roberto Carlos

    1992-12-01

    Thirty-two Polwarth ewes, of ages up to 1 year, were observed in a climatic chamber (24 to 45° C) for eight periods of 5 h each. The observations were made through a window in the chamber wall. All animals were observed four times, then shorn and observed four times again. The animals were given weighed quantities of water and feed consisting of commercial concentrate plus Rhodes grass ( Chloris gayana) hay. The water and feed remaining after 5 h of observation were weighed. The following traits were analysed: time eating hay (TEH), time eating concentrate (TEC), time drinking water (TDW), weight of hay eaten (WHE), weight of concentrate eaten (WCE), volume of ingested water (VIW), ruminating time standing up (RTS), ruminating time lying down (RTL), idling time standing up (ITS), and idling time lying down (ITL). Shearing had a significant effect for all traits except ITS. Shearing resulted in higher values for all traits except for ITS and ITL. Ingestion of hay (TEH and WHE) decreased with increased air temperature and humidity, while the ingestion of concentrate (TEC) and WHE) and water (TDW and VIW) increased. Rumination decreased with increased air temperature and humidity, and was higher in shorn than in unshorn sheep.

  19. Season and humidity dependence of the effects of air pollution on COPD hospitalizations in Hong Kong

    NASA Astrophysics Data System (ADS)

    Qiu, Hong; Yu, Ignatius Tak Sun; Wang, Xiaorong; Tian, Linwei; Tse, Lap Ah; Wong, Tze Wai

    2013-09-01

    Associations between ambient pollution and respiratory morbidity including chronic obstructive pulmonary disease (COPD) have been confirmed. Weather factors, such as temperature, season and relative humidity (RH), may modify the effects of air pollution. This time series study was conducted to examine whether the effects of air pollution on emergency COPD hospital admissions in Hong Kong varied across seasons and RH levels, and explore the possible joint modification of season and RH on the effects of pollution. Data of daily air pollution concentrations mean temperature and RH, and COPD hospital admissions from 1998 to 2007 were collected. Generalized additive Poisson models with interaction terms were used to estimate the effects of pollution across seasons and RH levels. We observed an increase in the detrimental effects of air pollution in the cool season and on low humidity days. On the cool and dry days, a 10 μg m-3 increment of lag03 exposure was associated with an increase in emergency COPD admissions by 1.76% (95%CI: 1.19-2.34%), 3.43% (95%CI: 2.80-4.07%), and 1.99% (95%CI: 0.90-3.09%) for nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2), respectively, all of which were statistically significantly higher than those on the other days. No consistent modification of weather factors was found for the effects of particles with an aerodynamic diameter less than 10 μm (PM10). The results suggested that season and RH jointly modified the effects of gaseous pollutants, resulting in increased emergency COPD hospitalizations on the cool and dry days.

  20. Temperature-modulated graphene oxide resistive humidity sensor for indoor air quality monitoring

    NASA Astrophysics Data System (ADS)

    de Luca, A.; Santra, S.; Ghosh, R.; Ali, S. Z.; Gardner, J. W.; Guha, P. K.; Udrea, F.

    2016-02-01

    In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide-semiconductor (CMOS) micro-electro-mechanical-system (MEMS) micro-hotplate technology for the monitoring and control of indoor air quality (IAQ). GO powder is obtained by chemical exfoliation, dispersed in water and deposited via ink-jet printing onto a low power micro-hotplate. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) show the typical layered and wrinkled morphology of the GO. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FTIR) spectroscopy indicate that the GO flakes possess a significant number of oxygen containing functional groups (epoxy, carbonyl, hydroxyl) extremely attractive for humidity detection. Electro-thermal characterisation of the micro-hotplates shows a thermal efficiency of 0.11 mW per °C, resulting in a sensor DC power consumption of only 2.75 mW at 50 °C. When operated in an isothermal mode, the sensor response is detrimentally affected by significant drift, hysteretic behaviour, slow response/recovery times and hence poor RH level discrimination. Conversely, a temperature modulation technique coupled with a differential readout methodology results in a significant reduction of the sensor drift, improved linear response with a sensitivity of 0.14 mV per %, resolution below 5%, and a maximum hysteresis of +/-5% response and recovery times equal to 189 +/- 49 s and 89 +/- 5 s, respectively. These performance parameters satisfy current IAQ monitoring requirements. We have thus demonstrated the effectiveness of integrating GO on a micro-hotplate CMOS-compatible platform enabling temperature modulation schemes to be easily applied in order to achieve compact, low power, low cost humidity IAQ monitoring.In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary

  1. Solar-Powered, Liquid-Desiccant Air Conditioner for Low-Electricity Humidity Control: Report and Summary Report

    SciTech Connect

    Dean, J.; Kozubal, E.; Herrmann, L.; Miller, J.; Lowenstein, A.; Barker, G.; Slayzak, S.

    2012-11-01

    The primary objective of this project was to demonstrate the capabilities of a new high-performance, liquid-desiccant dedicated outdoor air system (DOAS) to enhance cooling efficiency and comfort in humid climates while substantially reducing electric peak demand at Tyndall Air Force Base (AFB), which is 12 miles east of Panama City, Florida.

  2. Monthly mean large-scale analyses of upper-tropospheric humidity and wind field divergence derived from three geostationary satellites

    SciTech Connect

    Schmetz, J.; Menzel, W.P.; Hayden, C.

    1995-09-01

    This paper describes the results from a collaborative study between the European Space Operations Center, the European Organization for the Exploitation of Meteorological Satellites, the National Oceanic and Atmospheric Administration, and the Cooperative Institute for Meterological Satellite Studies investigating the relationship between satellite-derived monthly mean fields of wind and humidity in the upper troposphere for March 1994. Three geostationary meteorological satellites GOES-7, Meteosat-3, and Meteosat-5 are used to cover an area from roughly 160{degrees}W to 50{degrees}E. The wind fields are derived from tracking features in successive images of upper-tropospheric water vapor (WV) as depicted in the 6.5-{mu} absorption band. The upper-tropospheric relative humidity (UTH) is inferred from measured water vapor radiances with a physical retrieval scheme based on radiative forward calculations. Quantitative information on large-scale circulation patterns in the upper troposphere is possible with the dense spatial coverage of the WV wind vectors. The monthly mean wind field is used to estimate the large-scale divergence; values range between about -5 x 10{sup -6} and 5 x 10{sup -6} sec{sup -1} when averaged over a scale length of about 1000-2000 km. The spatial patterns of the UTH field and the divergence of the wind field closely resemble one another, suggesting that UTH patterns are principally determined by the large-scale circulation. Since the upper-tropospheric humidity absorbs upwelling radiation from lower-tropospheric levels and therefore contributes significantly to the atmospheric greenhouse effect, this work implies that studies on the climate relevance of water vapor should include three-dimensional modeling of the atmospheric dynamics. The fields of UTH and WV winds are useful parameters for a climate-monitoring system based on satellite data. 21 refs., 5 figs.

  3. Monthly mean large-scale analyses of upper-tropospheric humidity and wind field divergence derived from three geostationary satellites

    NASA Technical Reports Server (NTRS)

    Schmetz, Johannes; Menzel, W. Paul; Velden, Christopher; Wu, Xiangqian; Vandeberg, Leo; Nieman, Steve; Hayden, Christopher; Holmlund, Kenneth; Geijo, Carlos

    1995-01-01

    This paper describes the results from a collaborative study between the European Space Operations Center, the European Organization for the Exploitation of Meteorological Satellites, the National Oceanic and Atmospheric Administration, and the Cooperative Institute for Meteorological Satellite Studies investigating the relationship between satellite-derived monthly mean fields of wind and humidity in the upper troposphere for March 1994. Three geostationary meteorological satellites GOES-7, Meteosat-3, and Meteosat-5 are used to cover an area from roughly 160 deg W to 50 deg E. The wind fields are derived from tracking features in successive images of upper-tropospheric water vapor (WV) as depicted in the 6.5-micron absorption band. The upper-tropospheric relative humidity (UTH) is inferred from measured water vapor radiances with a physical retrieval scheme based on radiative forward calculations. Quantitative information on large-scale circulation patterns in the upper-troposphere is possible with the dense spatial coverage of the WV wind vectors. The monthly mean wind field is used to estimate the large-scale divergence; values range between about-5 x 10(exp -6) and 5 x 10(exp 6)/s when averaged over a scale length of about 1000-2000 km. The spatial patterns of the UTH field and the divergence of the wind field closely resemble one another, suggesting that UTH patterns are principally determined by the large-scale circulation. Since the upper-tropospheric humidity absorbs upwelling radiation from lower-tropospheric levels and therefore contributes significantly to the atmospheric greenhouse effect, this work implies that studies on the climate relevance of water vapor should include three-dimensional modeling of the atmospheric dynamics. The fields of UTH and WV winds are useful parameters for a climate-monitoring system based on satellite data. The results from this 1-month analysis suggest the desirability of further GOES and Meteosat studies to characterize

  4. Cloud-induced uncertainties in AIRS and ECMWF temperature and specific humidity

    NASA Astrophysics Data System (ADS)

    Wong, Sun; Fetzer, Eric J.; Schreier, Mathias; Manipon, Gerald; Fishbein, Evan F.; Kahn, Brian H.; Yue, Qing; Irion, Fredrick W.

    2015-03-01

    The uncertainties of the Atmospheric Infrared Sounder (AIRS) Level 2 version 6 specific humidity (q) and temperature (T) retrievals are quantified as functions of cloud types by comparison against Integrated Global Radiosonde Archive radiosonde measurements. The cloud types contained in an AIRS/Advanced Microwave Sounding Unit footprint are identified by collocated Moderate Resolution Imaging Spectroradiometer retrieved cloud optical depth (COD) and cloud top pressure. We also report results of similar validation of q and T from European Centre for Medium-Range Weather Forecasts (ECMWF) forecasts (EC) and retrievals from the AIRS Neural Network (NNW), which are used as the initial state for AIRS V6 physical retrievals. Differences caused by the variation in the measurement locations and times are estimated using EC, and all the comparisons of data sets against radiosonde measurements are corrected by these estimated differences. We report in detail the validation results for AIRS GOOD quality control, which is used for the AIRS Level 3 climate products. AIRS GOOD quality q reduces the dry biases inherited from the NNW in the middle troposphere under thin clouds but enhances dry biases in thick clouds throughout the troposphere (reaching -30% at 850 hPa near deep convective clouds), likely because the information contained in AIRS retrievals is obtained in cloud-cleared areas or above clouds within the field of regard. EC has small moist biases (~5-10%), which are within the uncertainty of radiosonde measurements, in thin and high clouds. Temperature biases of all data are within ±1 K at altitudes above the 700 hPa level but increase with decreasing altitude. Cloud-cleared retrievals lead to large AIRS cold biases (reaching about -2 K) in the lower troposphere for large COD, enhancing the cold biases inherited from the NNW. Consequently, AIRS GOOD quality T root-mean-squared errors (RMSEs) are slightly smaller than the NNW errors in thin clouds (1.5-2.5 K) but

  5. Interaction of temperature, humidity, driver preferences, and refrigerant type on air conditioning compressor usage.

    PubMed

    Levine, C; Younglove, T; Barth, M

    2000-10-01

    Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity. Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted. PMID:11288304

  6. Temperature-modulated graphene oxide resistive humidity sensor for indoor air quality monitoring.

    PubMed

    De Luca, A; Santra, S; Ghosh, R; Ali, S Z; Gardner, J W; Guha, P K; Udrea, F

    2016-02-28

    In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide-semiconductor (CMOS) micro-electro-mechanical-system (MEMS) micro-hotplate technology for the monitoring and control of indoor air quality (IAQ). GO powder is obtained by chemical exfoliation, dispersed in water and deposited via ink-jet printing onto a low power micro-hotplate. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) show the typical layered and wrinkled morphology of the GO. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FTIR) spectroscopy indicate that the GO flakes possess a significant number of oxygen containing functional groups (epoxy, carbonyl, hydroxyl) extremely attractive for humidity detection. Electro-thermal characterisation of the micro-hotplates shows a thermal efficiency of 0.11 mW per °C, resulting in a sensor DC power consumption of only 2.75 mW at 50 °C. When operated in an isothermal mode, the sensor response is detrimentally affected by significant drift, hysteretic behaviour, slow response/recovery times and hence poor RH level discrimination. Conversely, a temperature modulation technique coupled with a differential readout methodology results in a significant reduction of the sensor drift, improved linear response with a sensitivity of 0.14 mV per %, resolution below 5%, and a maximum hysteresis of ±5%; response and recovery times equal to 189 ± 49 s and 89 ± 5 s, respectively. These performance parameters satisfy current IAQ monitoring requirements. We have thus demonstrated the effectiveness of integrating GO on a micro-hotplate CMOS-compatible platform enabling temperature modulation schemes to be easily applied in order to achieve compact, low power, low cost humidity IAQ monitoring. PMID:26842731

  7. Repetitively pulsed atmospheric pressure discharge treatment of rough polymer surfaces: I. Humid air discharges

    NASA Astrophysics Data System (ADS)

    Bhoj, Ananth N.; Kushner, Mark J.

    2008-08-01

    Plasmas generated at atmospheric pressure are used to functionalize the surfaces of polymers by creating new surface-resident chemical groups. The polymers used in textiles and biomedical applications often have non-planar surfaces whose functionalization requires penetration of plasma generated species into sometimes complex surface features. In this regard, the atmospheric pressure plasma treatment of a rough polypropylene surface was computationally investigated using a two-dimensional plasma hydrodynamics model integrated with a surface kinetics model. Repetitively pulsed discharges produced in a dielectric barrier-corona configuration in humid air were considered to affix O. Macroscopic non-uniformities in treatment result from the spatial variations in radical densities which depend on the polarity of the discharge. Microscopic non-uniformities arise due to the higher reactivity of plasma produced species, such as OH radicals, which are consumed before they can diffuse deeper into surface features. The consequences of applied voltage magnitude and polarity, and the relative humidity on discharge dynamics and radical generation leading to surface functionalization, are discussed.

  8. Emissions of an AVCO Lycoming 0-320-DIAD air cooled light aircraft engine as a function of fuel-air ratio, timing, and air temperature and humidity

    NASA Technical Reports Server (NTRS)

    Meng, P. R.; Skorobatckyi, M.; Cosgrove, D. V.; Kempke, E. E., Jr.

    1976-01-01

    A carbureted aircraft engine was operated over a range of test conditions to establish the exhaust levels over the EPA seven-mode emissions cycle. Baseline (full rich production limit) exhaust emissions at an induction air temperature of 59 F and near zero relative humidity were 90 percent of the EPA standard for HC, 35 percent for NOx, and 161 percent for CO. Changes in ignition timing around the standard 25 deg BTDC from 30 deg BTDC to 20 deg BTDC had little effect on the exhaust emissions. Retarding the timing to 15 deg BTDC increased both the HC and CO emissions and decreased NOx emissions. HC and CO emissions decreased as the carburetor was leaned out, while NOx emissions increased. The EPA emission standards were marginally achieved at two leanout conditions. Variations in the quantity of cooling air flow over the engine had no effect on exhaust emissions. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased.

  9. Dependence on material choice of degradation of organic solar cells following exposure to humid air

    PubMed Central

    Glen, Tom S.; Scarratt, Nicholas W.; Yi, Hunan; Iraqi, Ahmed; Wang, Tao; Kingsley, James; Buckley, Alastair R.; Lidzey, David G.

    2015-01-01

    ABSTRACT Electron microscopy has been used to study the degradation of organic solar cells when exposed to humid air. Devices with various different combinations of commonly used organic solar cell hole transport layers and cathode materials have been investigated. In this way the ingress of water and the effect it has on devices could be studied. It was found that calcium and aluminum in the cathode both react with water, causing voids and delamination within the device. The use of poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was found to increase the degradation by easing water ingress into the device. Replacing these materials removed these degradation features. © 2015 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 216–224 PMID:27594763

  10. Utilization of rice husk silica as adsorbent for BTEX passive air sampler under high humidity condition.

    PubMed

    Areerob, Thanita; Grisdanurak, Nurak; Chiarakorn, Siriluk

    2016-03-01

    Selective adsorbent of benzene, toluene, ethylbenzene, and xylenes (BTEX) was developed based on mesoporous silica materials, RH-MCM-41. It was synthesized from rice husk silica and modified by silane reagents. The silane reagents used in this study were trimethylchlorosilane (TMS), triisopropylchlorosilane (TIPS), and phenyldimethylchlorosilane (PDMS). Physiochemical properties of synthesized materials were characterized by small-angle X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), and surface area analysis. Materials packed in passive air sampler were tested for BTEX uptake capacity. The tests were carried out under an influence of relative humidity (25 to 99 %). Overall, RH-MCM-41 modified by TMS outperformed compared to those modified by other silane agents. The comparative BTEX adsorption on this material and commercial graphitized carbon black was reported. PMID:26573315

  11. Hurricane Frances as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS) and SeaWinds

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image shows Hurricane Frances as captured by instruments onboard two different satellites: the AIRS infrared instrument onboard Aqua, and the SeaWinds scatterometer onboard QuikSCAT. Both are JPL-managed instruments. AIRS data are used to create global three-dimensional maps of temperature, humidity and clouds, while scatterometers measure surface wind speed and direction over the ocean.

    The red vectors in the image show Frances' surface winds as measured by SeaWinds on QuikSCAT. The background colors show the temperature of clouds and surface as viewed in the infrared by AIRS, with cooler areas pushing to purple and warmer areas are pushing to red. The color scale on the right gives the temperatures in degrees Kelvin. (The top of the scale, 320 degrees Kelvin, corresponds to 117 degrees Fahrenheit, and the bottom, 180 degrees K is -135 degrees F.) The powerful circulation of this storm is evident from the combined data as well as the development of a clearly-defined central 'eye'. The infrared signal does not penetrate through clouds, so the light blue areas reveal the cold clouds tops associated with strong thunderstorms embedded within the storm. In cloud-free areas the infrared signal comes from Earth's surface, revealing warmer temperatures.

    The power of the SeaWinds scatterometer data set lies in its ability to generate global maps of wind speed and direction, giving us a snapshot of how the atmosphere is circulating. Weather prediction centers, including the Tropical Prediction Center - a branch of NOAA that monitors the creation of ocean-born storms, use scatterometer data to help it 'see' where these storms are brewing so that warnings can be issued and the storms, with often erratic motions, can be tracked.

    While the SeaWinds instrument isn't designed to gather hurricane data, having difficulty seeing the surface in heavy rain, it's data can be used in combination with other data sets to give us an insight into these storms. In

  12. Indoor air quality assessment of daycare facilities with carbon dioxide, temperature, and humidity as indicators.

    PubMed

    Ferng, Shiaw-Fen; Lee, Li-Wen

    2002-11-01

    Poor indoor air quality (IAQ) in daycare facilities affects both attending children and care providers. Incident rates of upper-respiratory-tract infections have been reported to be higher in children who attend daycare. Excessive carbon dioxide (CO2) exposure can cause several health effects and even sudden infant death. For this study, 26 facilities were randomly selected in a Midwestern county of the United States. CO2, room temperature, and relative humidity were used as indicators for IAQ and comfort levels. These IAQ parameters were continuously monitored for eight hours at each facility by a direct-reading instrument that was calibrated before each measurement. More than 50 percent of the facilities had an average CO2 level over the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) standard of 1,000 parts per million (ppm). For temperature and relative humidity, respectively, 42.3 percent and 15.4 percent of facilities were outside of the ASHRAE-recommended comfort zones. The nap-time average CO2 level was about 117 ppm higher than the non-nap-time level. The increment of the nap-time CO2 level in the sleeping-only room over the level in multipurpose rooms was statistically significant (p < .05). According to stepwise multiple regression analysis, nap-time CO2 level was predicted by CO2 level before occupancy, nap-time average temperature, carbon monoxide, and child density (R2 = .83). It is recommended that an appropriate IAQ standard for daycare facilities be established and that children should not be placed in a completely isolated room during nap time. PMID:12415886

  13. Effects of Environmental Humidity and Temperature on Sterilization Efficiency of Dielectric Barrier Discharge Plasmas in Atmospheric Pressure Air

    NASA Astrophysics Data System (ADS)

    Kikuchi, Yusuke; Miyamae, Masanori; Nagata, Masayoshi; Fukumoto, Naoyuki

    2011-01-01

    The inactivation of Bacillus atrophaeus spores by a dielectric barrier discharge (DBD) plasma in atmospheric humid air was investigated in order to develop a low-temperature, low-cost, and high-speed plasma sterilization technique. The biological indicators covered with a Tyvek sheet were set just outside the DBD plasma region, where air temperature and humidity as a discharge gas were precisely controlled by an environmental test chamber. The results show that the inactivation of B. atrophaeus spores was found to be dependent strongly on humidity, and was completed within 15 min at a relative humidity of 90% and a temperature of 30 °C. The treatment time for sterilization is shorter than those of conventional sterilization methods using ethylene oxide gas and dry heat treatment. The inactivation rates depend on not only relative humidity but also temperature, so that water content in air could determine the generation of reactive species such as hydroxyl radicals that are effective for the inactivation of B. atrophaeus spores.

  14. Combining microwave radiometer and wind profiler radar measurements to improve accuracy and resolution of atmospheric humidity profiling

    NASA Astrophysics Data System (ADS)

    Bianco, L.; Cimini, D.; Ware, R.; Marzano, F.

    2003-04-01

    An algorithm to compute high-resolution atmospheric humidity profiling by synergetic use of microwave radiometer and wind profiler radar is illustrated. Wind profiler radar data are input for the computation of the potential refractivity gradient profiles, and combined with radiometer estimates of temperature profiles, which are needed to fully retrieve humidity gradient profiles. The algorithm makes use of recent developments in Wind Profiler Radar (WPR) signal processing, computing the zeroth, first, and second moments of WPR Doppler spectra via a fuzzy logic method (Bianco and Wilczak, 2002), which provides quality control of radar data in the spectral domain. The zeroth, first, and second moments are employed to compute the structure parameter of potential refractivity (C_φ^2), the horizontal wind (V_h), and the structure parameter of vertical velocity (C_w^2) respectively (Stankov et al. 2002). In addition, the algorithm uses a formula proposed by White (White et al. 1999) for the computation of C_w^2, to account for the spatial and temporal filtering effects on the Doppler spectrum. C_φ^2, V_h, and C_w^2 are then combined together to retrieve the potential refractivity gradient profiles. On the radiometric side, a first attempt is made using low resolution temperature profile estimates obtained following the algorithm described by Han and Westwater (1995), which make use of ground-based sensors, including a dual channel microwave radiometer (MWR), and other surface meteorological instruments. Then, the advantages of using estimates of temperature and humidity profiles from a multichannel microwave radiometer profiler (MWRP) are evaluated. Finally, the combined algorithm performances in retrieving humidity profiles are tested with simultaneous radiosonde "in situ" measurements. The empirical sets of WPR and MWR data were provided by the Atmospheric Radiation Measurement (ARM) Program, and collected at the ARM Southern Great Plains (SGP) site (latitude: 36^o

  15. Combining Microwave Radiometer and Wind Profiler Radar Measurements to Improve Accuracy and Resolution of Atmospheric Humidity Profiling

    NASA Astrophysics Data System (ADS)

    Bianco, L.; Cimini, D.; Ware, R.; Marzano, F.

    2003-04-01

    An algorithm to compute high-resolution atmospheric humidity profiling by synergetic use of microwave radiometer and wind profiler radar is illustrated. Wind profiler radar data are input for the computation of the potential refractivity gradient profiles, and combined with radiometer estimates of temperature profiles, which are needed to fully retrieve humidity gradient profiles. The algorithm makes use of recent developments in Wind Profiler Radar (WPR) signal processing, computing the zeroth, first, and second moments of WPR Doppler spectra via a fuzzy logic method (Bianco and Wilczak, 2002), which provides quality control of radar data in the spectral domain. The zeroth, first, and second moments are employed to compute the structure parameter of potential refractivity (C_φ^2), the horizontal wind (V_h), and the structure parameter of vertical velocity (C_w^2) respectively (Stankov et al. 2002). In addition, the algorithm uses a formula proposed by White (White et al. 1999) for the computation of C_w^2, to account for the spatial and temporal filtering effects on the Doppler spectrum. C_φ^2, V_h, and C_φ^2 are then combined together to retrieve the potential refractivity gradient profiles. On the radiometric side, a first attempt is made using low resolution temperature profile estimates obtained following the algorithm described by Han and Westwater (1995), which make use of ground-based sensors, including a dual channel microwave radiometer (MWR), and other surface meteorological instruments. Then, the advantages of using estimates of temperature and humidity profiles from a multichannel microwave radiometer profiler (MWRP) are evaluated. Finally, the combined algorithm performances in retrieving humidity profiles are tested with simultaneous radiosonde "in situ" measurements. The empirical sets of WPR and MWR data were provided by the Atmospheric Radiation Measurement (ARM) Program, and collected at the ARM Southern Great Plains (SGP) site (latitude: 36^o

  16. Interaction of humidity and air pollutants on vegetation. Final report, 16 July 1986-30 April 1988

    SciTech Connect

    Thompson, C.R.; Olszyk, D.M.

    1988-03-01

    This study used a humidification system that adds dry steam to open-top field chambers to determine how relative-humidity affects plant responses to air pollutants in the field. There was a definite interaction between humidity and air pollution on leaf injury, with increasing humidity greatly increasing the amount of visible leaf necrosis and senescence from ozone. However, the injury interaction was not associated with any general interaction in terms of crop yield. Ozone caused visible injury to tomatoes, almonds, beans, and melons; reduced yield, growth, and biomass production for tomatoes and beans; and reduced physiological processes for tomatoes, beans, and almonds. Sulfur dioxide reduced growth and biomass production in wheat and lettuce, and yield for wheat. Humidification increased biomass production for tomatoes, carrots, onions, and beans, yield for carrots, onions, and lettuce, but decreased yields in beans.

  17. Impacts of wind farms on surface air temperatures

    PubMed Central

    Baidya Roy, Somnath; Traiteur, Justin J.

    2010-01-01

    Utility-scale large wind farms are rapidly growing in size and numbers all over the world. Data from a meteorological field campaign show that such wind farms can significantly affect near-surface air temperatures. These effects result from enhanced vertical mixing due to turbulence generated by wind turbine rotors. The impacts of wind farms on local weather can be minimized by changing rotor design or by siting wind farms in regions with high natural turbulence. Using a 25-y-long climate dataset, we identified such regions in the world. Many of these regions, such as the Midwest and Great Plains in the United States, are also rich in wind resources, making them ideal candidates for low-impact wind farms. PMID:20921371

  18. Near Decade Long Tropospheric Air Temperature and Specific Humidity Records from AIRS for CMIP5 Model Evaluation

    NASA Astrophysics Data System (ADS)

    Tian, B.; Fetzer, E.; Kahn, B. H.; Teixeira, J.; Manning, E.; Hearty, T. J.

    2012-12-01

    The peer-reviewed analyses of multi-model outputs from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) experiments will be the most important basis for the next Intergovernmental Panel on Climate Change (IPCC) Assessment Report (AR5). To increase the fidelity of the IPCC AR5, an Obs4MIPs project has been initiated to collect some well-established and well-documented datasets, to organize them according to the CMIP5 model output requirements, and makes them available to the science community for CMIP5 model evaluation. The NASA Atmospheric Infrared Sounder (AIRS) project has produced monthly mean tropospheric air temperature (ta, K) and specific humidity (hus, kg/kg) products as part of the Obs4MIPS project. In this paper, we first describe these two AIRS datasets in terms of data description, origin, validation and caveats for model-observation comparison. We then document the climatological mean features of these two AIRS datasets and compare them to those from NASA's Modern Era Retrospective analysis for Research and Applications (MERRA) for AIRS data validation and CMIP5 model simulations for CMIP5 model evaluation. As expected, the 9-year AIRS data show several well-known climatological features of tropospheric ta and hus, such as the strong meridional and vertical gradients of tropospheric ta and hus and strong zonal gradient of tropospheric hus. AIRS data also show the strong connections between the tropospheric hus, atmospheric circulation and deep convection. In comparison to MERRA, AIRS seems to be colder in the free troposphere but warmer in the boundary layer with differences typically less than 1 K. AIRS is wetter (~10%) in the tropical boundary layer but drier (around 30%) in the tropical free troposphere and the extratropical troposphere. In particular, the large AIRS-MERRA hus differences are mainly located in the cloudy regions, such as the Intertropical Convergence Zone (ITCZ), the South Pacific Convergence Zone (SPCZ) and the

  19. 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,...

  20. Elevated air movement enhances stomatal sensitivity to abscisic acid in leaves developed at high relative air humidity

    PubMed Central

    Carvalho, Dália R. A.; Torre, Sissel; Kraniotis, Dimitrios; Almeida, Domingos P. F.; Heuvelink, Ep; Carvalho, Susana M. P.

    2015-01-01

    High relative air humidity (RH ≥ 85%) during growth leads to stomata malfunctioning, resulting in water stress when plants are transferred to conditions of high evaporative demand. In this study, we hypothesized that an elevated air movement (MOV) 24 h per day, during the whole period of leaf development would increase abscisic acid concentration ([ABA]) enhancing stomatal functioning. Pot rose ‘Toril’ was grown at moderate (61%) or high (92%) RH combined with a continuous low (0.08 m s-1) or high (0.92 m s-1) MOV. High MOV reduced stomatal pore length and aperture in plants developed at high RH. Moreover, stomatal function improved when high MOV-treated plants were subjected to leaflet desiccation and ABA feeding. Endogenous concentration of ABA and its metabolites in the leaves was reduced by 35% in high RH, but contrary to our hypothesis this concentration was not significantly affected by high MOV. Interestingly, in detached leaflets grown at high RH, high MOV increased stomatal sensitivity to ABA since the amount of exogenous ABA required to decrease the transpiration rate was significantly reduced. This is the first study to show that high MOV increases stomatal functionality in leaves developed at high RH by reducing the stomatal pore length and aperture and enhancing stomatal sensitivity to ABA rather than increasing leaf [ABA]. PMID:26074943

  1. Hurricane Isabel, AIRS Infrared and SeaWinds Scatterometer Data Combined

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

    These two images show Hurricane Isabel as viewed by AIRS and each of the two SeaWinds scatterometers on the ADEOS-2 and QuikScat satellites, all JPL-managed experiments. AIRS data are used to create global three-dimensional maps of temperature, humidity and clouds, while scatterometers measure surface wind speed and direction.

    Figure 1 shows Isabel on September 13, 2003, when it was a Category 5 storm threatening the Caribbean and southern United States. At the time Isabel was the strongest Atlantic storm since hurricane Mitch killed thousands in central America in 1997. The red vectors in the image show Isabel's surface winds as measured by SeaWinds on ADEOS-2, and the background colors show the temperature of clouds and surface, as viewed in the infrared by AIRS. The hurricane's powerful swirling winds are apparent. These winds circle the hurricane's eye, seen as the red dot near the middle top of the image. Light blue areas shows adjacent cold clouds tops associated with strong thunderstorms embedded within the storm.

    Figure 2 shows Isabel as it approached landfall on the outer banks of North Carolina on September 18. The hurricane weakened in the five days since the earlier image was observed, as indicated by a less clearly defined eye. Nevertheless, it was still a powerful storm. The winds blowing onshore north of the eye knocked over trees, blew roofs off buildings, and drove large waves that breached the coastal barrier islands in many places. Water, transportation and power are still not fully restored to many of the areas in the image. The winds apparently blowing away from the eye of the storm are an artifact of one of the hurricane's other destructive phenomena: rain. The darkest blue clouds observed by AIRS show the most intense thunderstorms, and hence the heaviest rains. Hard rain fools the the SeaWinds on Quik

  2. Crystallization of spray-dried lactose/protein mixtures in humid air

    NASA Astrophysics Data System (ADS)

    Shawqi Barham, A.; Kamrul Haque, Md.; Roos, Yrjö H.; Kieran Hodnett, B.

    2006-10-01

    An in situ crystallization technique with X-ray diffraction analysis complemented by ex situ scanning electron microscopy and chromatographic analysis of the α/( α+ β) solid-state anomeric ratios has been developed to study the crystallization of lactose/protein mixtures in humid air. This technique was used to determine changes in phase composition and morphology during crystallization. Following an induction period during which water is sorbed, crystallization is rapid and the predominant phase observed using the in situ method in spray-dried lactose/sodium-caseinate, albumin and gelatin is α-lactose monohydrate. However, in the case of spray-dried lactose/whey protein isolate (WPI) the predominant phase that appears is the α/ β mixed phase with smaller amounts of α-lactose monohydrate. With pure lactose the α/ β mixed phase appears as a transient shortly after the onset of crystallization and α-lactose monohydrate and β-lactose both appear as stable crystalline phases at longer times. Another transient phase with 2 θ=12.2°, 20.7° and 21.8° was observed in spray-dried lactose/albumin. This phase decomposed as α-lactose monohydrate developed. Three phases seem to persist in the case of spray-dried lactose/gelatin, namely the phase with peaks at 2 θ=12.2°, 20.7° and 21.8°, α-lactose monohydrate and β-lactose for the duration of the in situ experiment.

  3. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    PubMed Central

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

  4. Stress response of Escherichia coli induced by surface streamer discharge in humid air

    NASA Astrophysics Data System (ADS)

    Doležalová, Eva; Prukner, Václav; Lukeš, Petr; Šimek, Milan

    2016-02-01

    Inactivation of Escherichia coli by means of surface streamer discharge has been investigated to obtain new insights into the key mechanisms involved, with a particular emphasis placed on the microbial response to plasma-induced stress. The surface streamer discharge was produced in coplanar dielectric barrier discharge electrode geometry, and was driven by an amplitude-modulated ac high voltage in humid synthetic air at atmospheric pressure. The response to plasma-induced stress was evaluated by using conventional cultivation, sublethal injury and resazurin assay and the LIVE/DEAD® BacLight™ Bacterial Viability kit. Compared to conventional cultivation, the LIVE/DEAD® test labels bacteria with damaged membranes, while resazurin assay tracks their metabolic activity. Our results clearly demonstrate that the treated bacteria partly lost their ability to grow properly, i.e. they became injured and culturable, or even viable but nonculturable (VBNC). The ability to develop colonies could have been lost due to damage of the bacterial membrane. Damage of the membranes was mainly caused by the lipid peroxidation, evidencing the key role of oxygen reactive species, in particular ozone. We conclude that the conventional cultivation method overestimates the decontamination efficiency of various plasma sources, and must therefore be complemented by alternative techniques capable of resolving viable but nonculturable bacteria.

  5. Effect of relative humidity and air temperature on survival of hepatitis A virus on environmental surfaces.

    PubMed Central

    Mbithi, J N; Springthorpe, V S; Sattar, S A

    1991-01-01

    Stainless steel disks (diameter, 1 cm) were contaminated with fecally suspended hepatitis A virus (HAV; strain HM-175) and held at low (25% +/- 5%), medium (55% +/- 5%), high (80% +/- 5%), or ultrahigh (95% +/- 5%) relative humidity (RH) at an air temperature of 5,20, or 35 degrees C. HAV survival was inversely proportional to the level of RH and temperature, and the half-lives of the virus ranged from greater than 7 days at the low RH and 5 degrees C to about 2 h at the ultrahigh RH and 35 degrees C. In parallel tests with fecally suspended Sabin poliovirus (PV) type 1 at the low and ultrahigh RH, all PV activity was lost within 4 h at the low RH whereas at the ultrahigh RH it remained detectable up to 12 h. HAV could therefore survive much better than PV on nonporous environmental surfaces. Moreover, the ability of HAV to survive better at low levels of RH is in direct contrast to the behavior of other enteroviruses. These findings should help in understanding the genesis of HAV outbreaks more clearly and in designing better measures for their control and prevention. PMID:1649579

  6. Energy-Efficient Supermarket Heating, Ventilation, and Air Conditioning in Humid Climates in the United States

    SciTech Connect

    Clark, J.

    2015-03-01

    Supermarkets are energy-intensive buildings that consume the greatest amount of electricity per square foot of building of any building type in the United States and represent 5% of total U.S. commercial building primary energy use (EIA 2005). Refrigeration and heating, ventilation, and air-conditioning (HVAC) systems are responsible for a large proportion of supermarkets’ total energy use. These two systems sometimes work together and sometimes compete, but the performance of one system always affects the performance of the other. To better understand these challenges and opportunities, the Commercial Buildings team at the National Renewable Energy Laboratory investigated several of the most promising strategies for providing energy-efficient HVAC for supermarkets and quantified the resulting energy use and costs using detailed simulations. This research effort was conducted on behalf of the U.S. Department of Energy (DOE) Commercial Building Partnerships (CBP) (Baechler et al. 2012; Parrish et al. 2013; Antonopoulos et al. 2014; Hirsch et al. 2014). The goal of CBP was to reduce energy use in the commercial building sector by creating, testing, and validating design concepts on the pathway to net zero energy commercial buildings. Several CBP partners owned or operated buildings containing supermarkets and were interested in optimizing the energy efficiency of supermarket HVAC systems in hot-humid climates. These partners included Walmart, Target, Whole Foods Market, SUPERVALU, and the Defense Commissary Agency.

  7. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    NASA Astrophysics Data System (ADS)

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-07-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface.

  8. Effect of single silica gel particle adsorption on the transport processes in a humid air stream

    NASA Astrophysics Data System (ADS)

    Sanyal, Apratim; Basu, Saptarshi; Kumar, Pramod

    2013-11-01

    The effect of adsorption due to a single silica gel particle on a convective field consisting of humid air has been investigated numerically. The adsorption is incorporated as a sink term in the transport equation for species (water vapor) and has been modeled using Linear Driving Force model, while the heat released due to adsorption is taken as source term in the energy equation and proportional to the amount of water vapor adsorbed. The heat released creates a coupling between the species and the temperature field as the adsorption characteristics are directly influenced by particle temperature. The extent of species and temperature boundary layer show the diffusion of the adsorption effects into the free stream. Surface adsorption is found to decrease with Reynolds no. The particle surface temperature increases from forward stagnation point till downstream. This work provides a model for understanding the adsorption kinetics in convective stream for other adsorbate-adsorbent pair. Further more complex scenarios can be modeled such as presence of multiple adsorbent particles, the interaction of species and temperature boundary layers setup due to individual particles and their influence on the overall adsorption characteristics.

  9. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air.

    PubMed

    Hassan, Ghassan; Yilbas, B S; Said, Syed A M; Al-Aqeeli, N; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

  10. A comparison of humid air turbine (HAT) cycle and combined-cycle power plants

    SciTech Connect

    Rao, A.D.; Francuz, V.J.; Shen, J.C.; West, E.W. )

    1991-03-01

    The Humid Air Turbine (HAT) cycle is a combustion turbine-based power generating cycle that provides an alternative to combined-cycle power generation. The HAT cycle differs from combined cycles in that it eliminates the steam turbine bottoming cycle by vaporizing water into the turbine's combustion air with heat obtained from the combustion turbine exhaust and other heat sources. This report presents the results of a study conducted by Fluor Daniel, Inc. for EPRI in which the HAT cycle was compared with combined-cycle plants in integration with the Texaco coal gasification process, and in natural gas-fired plants. The comparison of the coal gasification-based power plants utilizing the HAT cycle with Texaco coal gasification-based combined-cycle plants indicate that HAT cycle-based plants are less expensive and produce less environmental emissions. Whereas the combined-cycle plants require the use of expensive syngas coolers to achieve high efficiencies, the HAT cycle plants can achieve similar high efficiencies without the use of such equipment, resulting in a significant savings in capital cost and a reduction in levelized cost of electricity of up to 15%. In addition, HAT cycle plants produce very low levels of NO{sub x} emissions, possibly as little as 6 ppmv (dry, 15% O{sub 2} basis) without requiring the use of control technologies such as selective catalytic reduction. In natural gas-fired plants, the HAT cycle was calculated to have as much as a 4 percentage point gain in efficiency over the combined cycle and a potential for substantial reductions in NO{sub x} emissions, CO{sub 2} emissions, and water consumption. 71 figs., 74 tabs.

  11. Temperature, humidity and air flow in the emplacement drifts using convection and dispersion transport models

    SciTech Connect

    Danko, G.; Birkholzer, J.T.; Bahrami, D.; Halecky, N.

    2009-10-01

    A coupled thermal-hydrologic-airflow model is developed, solving for the transport processes within a waste emplacement drift and the surrounding rockmass together at the proposed nuclear waste repository at Yucca Mountain. Natural, convective air flow as well as heat and mass transport in a representative emplacement drift during post-closure are explicitly simulated, using the MULTIFLUX model. The conjugate, thermal-hydrologic transport processes in the rockmass are solved with the TOUGH2 porous-media simulator in a coupled way to the in-drift processes. The new simulation results show that large-eddy turbulent flow, as opposed to small-eddy flow, dominate the drift air space for at least 5000 years following waste emplacement. The size of the largest, longitudinal eddy is equal to half of the drift length, providing a strong axial heat and moisture transport mechanism from the hot to the cold drift sections. The in-drift results are compared to those from simplified models using a surrogate, dispersive model with an equivalent dispersion coefficient for heat and moisture transport. Results from the explicit, convective velocity simulation model provide higher axial heat and moisture fluxes than those estimated from the previously published, simpler, equivalent-dispersion models, in addition to showing differences in temperature, humidity and condensation rate distributions along the drift length. A new dispersive model is also formulated, giving a time- and location-variable function that runs generally about ten times higher in value than the highest dispersion coefficient currently used in the Yucca Mountain Project as an estimate for the equivalent dispersion coefficient in the emplacement drift. The new dispersion coefficient variation, back-calculated from the convective model, can adequately describe the heat and mass transport processes in the emplacement drift example.

  12. Air humidity as key determinant of morphogenesis and productivity of the rare temperate woodland fern Polystichum braunii.

    PubMed

    Schwerbrock, R; Leuschner, C

    2016-07-01

    (1) Most ferns are restricted to moist and shady habitats, but it is not known whether soil moisture or atmospheric water status are decisive limiting factors, or if both are equally important. (2) Using the rare temperate woodland fern Polystichum braunii, we conducted a three-factorial climate chamber experiment (soil moisture (SM) × air humidity (RH) × air temperature (T)) to test the hypotheses that: (i) atmospheric water status (RH) exerts a similarly large influence on the fern's biology as soil moisture, and (ii) both a reduction in RH and an increase in air temperature reduce vigour and growth. (3) Nine of 11 morphological, physiological and growth-related traits were significantly influenced by an increase in RH from 65% to 95%, leading to higher leaf conductance, increased above- and belowground productivity, higher fertility, more epidermal trichomes and fewer leaf deformities under high air humidity. In contrast, soil moisture variation (from 66% to 70% in the moist to ca. 42% in the dry treatment) influenced only one trait (specific leaf area), and temperature variation (15 °C versus 19 °C during daytime) only three traits (leaf conductance, root/shoot ratio, specific leaf area); RH was the only factor affecting productivity. (4) This study is the first experimental proof for a soil moisture-independent air humidity effect on the growth of terrestrial woodland ferns. P. braunii appears to be an air humidity hygrophyte that, whithin the range of realistic environmental conditions set in this study, suffers more from a reduction in RH than in soil moisture. A climate warming-related increase in summer temperatures, however, seems not to directly threaten this endangered species. PMID:26891763

  13. The Use of Red Green Blue Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-Convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Zavodsky, B. T.; Moltham, A. L.; Folmer, M. J.; Jedlovec, G. J.

    2014-01-01

    The investigation of non-convective winds associated with passing extratropical cyclones and the formation of the sting jet in North Atlantic cyclones that impact Europe has been gaining interest. Sting jet research has been limited to North Atlantic cyclones that impact Europe because it is known to occur in Shapiro-Keyser cyclones and theory suggests it does not occur in Norwegian type cyclones. The global distribution of sting jet cyclones is unknown and questions remain as to whether cyclones with Shapiro-Keyser characteristics that impact the United States develop features similar to the sting jet. Therefore unique National Aeronautics and Space Administration (NASA) products were used to analyze an event that impacted the Northeast United States on 09 February 2013. Moderate Resolution Imaging Spectroradiometer (MODIS) Red Green Blue (RGB) Air Mass imagery and Atmospheric Infrared Sounder (AIRS) ozone data were used in conjunction with NASA's global Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis and higher-resolution regional 13-km Rapid Refresh (RAP) data to analyze the role of stratospheric air in producing high winds. The RGB Air Mass imagery and a new AIRS ozone anomaly product were used to confirm the presence of stratospheric air. Plan view and cross sectional plots of wind, potential vorticity, relative humidity, omega, and frontogenesis were used to analyze the relationship between stratospheric air and high surface winds during the event. Additionally, the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to plot trajectories to determine the role of the conveyor belts in producing the high winds. Analyses of new satellite products, such as the RGB Air Mass imagery, show the utility of future GOES-R products in forecasting non-convective wind events.

  14. Comparison of absolute and relative air humidity sensors fabricated with inkjet printing technology

    NASA Astrophysics Data System (ADS)

    Selma, R.; Tarapata, G.; Marzecki, M.

    2015-09-01

    This paper describes design, manufacturing and testing of novelty humidity sensors manufactured in inkjet printing technology. Two types of sensors were produced - sensor for dew point hygrometer, along with heater and thermistor, and a relative humidity sensor. Both were tested and proven to be functional, with both advantages and disadvantages described further in the article.

  15. Elevated air humidity affects hydraulic traits and tree size but not biomass allocation in young silver birches (Betula pendula)

    PubMed Central

    Sellin, Arne; Rosenvald, Katrin; Õunapuu-Pikas, Eele; Tullus, Arvo; Ostonen, Ivika; Lõhmus, Krista

    2015-01-01

    As changes in air temperature, precipitation, and air humidity are expected in the coming decades, studies on the impact of these environmental shifts on plant growth and functioning are of major importance. Greatly understudied aspects of climate change include consequences of increasing air humidity on forest ecosystems, predicted for high latitudes. The main objective of this study was to find a link between hydraulic acclimation and shifts in trees’ resource allocation in silver birch (Betula pendula Roth) in response to elevated air relative humidity (RH). A second question was whether the changes in hydraulic architecture depend on tree size. Two years of application of increased RH decreased the biomass accumulation in birch saplings, but the biomass partitioning among aboveground parts (leaves, branches, and stems) remained unaffected. Increased stem Huber values (xylem cross-sectional area to leaf area ratio) observed in trees under elevated RH did not entail changes in the ratio of non-photosynthetic to photosynthetic tissues. The reduction of stem–wood density is attributable to diminished mechanical load imposed on the stem, since humidified trees had relatively shorter crowns. Growing under higher RH caused hydraulic conductance of the root system (KR) to increase, while KR (expressed per unit leaf area) decreased and leaf hydraulic conductance increased with tree size. Saplings of silver birch acclimate to increasing air humidity by adjusting plant morphology (live crown length, slenderness, specific leaf area, and fine-root traits) and wood density rather than biomass distribution among aboveground organs. The treatment had a significant effect on several hydraulic properties of the trees, while the shifts were largely associated with changes in tree size but not in biomass allocation. PMID:26528318

  16. Degradation mechanism of CH3NH3PbI3 perovskite materials upon exposure to humid air

    NASA Astrophysics Data System (ADS)

    Shirayama, Masaki; Kato, Masato; Miyadera, Tetsuhiko; Sugita, Takeshi; Fujiseki, Takemasa; Hara, Shota; Kadowaki, Hideyuki; Murata, Daisuke; Chikamatsu, Masayuki; Fujiwara, Hiroyuki

    2016-03-01

    Low stability of organic-inorganic perovskite (CH3NH3PbI3) solar cells in humid air environments is a serious drawback which could limit practical application of this material severely. In this study, from real-time spectroscopic ellipsometry characterization, the degradation mechanism of ultra-smooth CH3NH3PbI3 layers prepared by a laser evaporation technique is studied. We present evidence that the CH3NH3PbI3 degradation in humid air proceeds by two competing reactions of (i) the PbI2 formation by the desorption of CH3NH3I species and (ii) the generation of a CH3NH3PbI3 hydrate phase by H2O incorporation. In particular, rapid phase change occurs in the near-surface region and the CH3NH3PbI3 layer thickness reduces rapidly in the initial 1 h air exposure even at a low relative humidity of 40%. After the prolonged air exposure, the CH3NH3PbI3 layer is converted completely to hexagonal platelet PbI2/hydrate crystals that have a distinct atomic-scale multilayer structure with a period of 0.65 ± 0.05 nm. We find that conventional x-ray diffraction and optical characterization in the visible region, used commonly in earlier works, are quite insensitive to the surface phase change. Based on results obtained in this work, we discuss the degradation mechanism of CH3NH3PbI3 in humid air.

  17. Effect of air temperature and relative humidity at various fuel-air ratios on exhaust emissions on a per-mode basis of an Avco Lycoming 0-320 DIAD light aircraft engine. Volume 2: Individual data points

    NASA Technical Reports Server (NTRS)

    Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempke, E. R.

    1976-01-01

    A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions included carburetor lean-out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel-air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity. Volume II contains the data taken at each of the individual test points.

  18. Effect of Air Temperature and Relative Humidity at Various Fuel-Air Ratios on Exhaust Emissions on a Per-Mode Basis of an AVCO Lycoming 0-320 Diad Light Aircraft Engine: Volume 1: Results and Plotted Data

    NASA Technical Reports Server (NTRS)

    Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempe, E. E., Jr.

    1978-01-01

    A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions include carburetor lean out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity.

  19. Vandenberg Air Force Base Pressure Gradient Wind Study

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.

    2013-01-01

    Warning category winds can adversely impact day-to-day space lift operations at Vandenberg Air Force Base (VAFB) in California. NASA's Launch Services Program and other programs at VAFB use wind forecasts issued by the 30 Operational Support Squadron Weather Flight (30 OSSWF) to determine if they need to limit activities or protect property such as a launch vehicle. The 30 OSSWF tasked the AMU to develop an automated Excel graphical user interface that includes pressure gradient thresholds between specific observing stations under different synoptic regimes to aid forecasters when issuing wind warnings. This required the AMU to determine if relationships between the variables existed.

  20. Effects of Ambient Humidity on Plant Growth Enhancement by Atmospheric Air Plasma Irradiation to Plant Seeds

    NASA Astrophysics Data System (ADS)

    Sarinont, Thapanut; Amano, Takaaki; Koga, Kazunori; Shiratani, Masaharu

    2015-09-01

    Humidity is an important factor for plasma-bio applications because composition of species generated by atmospheric pressure plasmas significantly depends on the humidity. Here we have examined effects of humidity on the growth enhancement to study the mechanism. Experiments were carried out with a scalable DBD device. 10 seeds of Raphanus sativus L. were set for x = 5 mm and y = 3 mm below the electrodes. The humidity Hair was 10 - 90 %Rh. The ratio of length of plants with plasma irradiation to that of control increases from 1.2 for Hair = 10 %Rh to 2.5 for Hair = 50 %Rh. The ratio is 2.5 for Hair = 50-90 %Rh. This humidity dependence is similar to the humidity dependence of O2+-H2O,H3O*, NO2--H2Oand NO3--H2Odensities, whereas it is different from that of other species such as O3, NO, and so on. The similarity gives information on key species for the growth enhancement.

  1. Measuring Relative Humidity.

    ERIC Educational Resources Information Center

    Pinkham, Chester A.; Barrett, Kristin Burrows

    1992-01-01

    Describes four experiments that enable students to explore the phenomena of evaporation and condensation and determine the relative humidity by measuring air temperature and dew point on warm September days. Provides tables to calculate saturation points and relative humidity. (MDH)

  2. Tangential stress beneath wind-driven air water interfaces

    NASA Astrophysics Data System (ADS)

    Banner, Michael L.; Peirson, William L.

    1998-06-01

    The detailed structure of the aqueous surface sublayer flow immediately adjacent to the wind-driven air water interface is investigated in a laboratory wind-wave flume using particle image velocimetry (PIV) techniques. The goal is to investigate quantitatively the character of the flow in this crucial, very thin region which is often disrupted by microscale breaking events. In this study, we also examine critically the conclusions of Okuda, Kawai & Toba (1977), who argued that for very short, strongly forced wind-wave conditions, shear stress is the dominant mechanism for transmitting the atmospheric wind stress into the water motion waves and surface drift currents. In strong contrast, other authors have more recently observed very substantial normal stress contributions on the air side. The availability of PIV and associated image technology now permits a timely re-examination of the results of Okuda et al., which have been influential in shaping present perceptions of the physics of this dynamically important region. The PIV technique used in the present study overcomes many of the inherent shortcomings of the hydrogen bubble measurements, and allows reliable determination of the fluid velocity and shear within 200 [mu]m of the instantaneous wind-driven air water interface.

  3. Analysis and Numerical Simulation of Humidity Halos around Trade Wind Cumulus Clouds

    NASA Astrophysics Data System (ADS)

    Lu, M.; Wang, J.; Freedman, A.; Jonsson, H. H.; Flagan, R. C.; McClatchey, R. A.; Seinfeld, J. H.

    2002-12-01

    Significant enhancements in humidity above that in the cloud-free atmosphere have been found in the vicinity of isolated cumulus clouds, so-called cloud halos. Cloud halos can reflect features of cloud evolution, increase shortwave atmospheric radiative absorption, and may serve as a predominant region of new particle formation. We report results of an aircraft campaign off Oahu, Hawaii during August 2001, aimed at characterizing the humidity properties around isolated cumulus clouds at 10 m spatial resolution by a novel high-speed spectroscopic water vapor concentration monitor developed by Aerodyne Research, Inc. Analysis of the measurements adds to the existing body of information on cloud halos, their frequency of occurrence, spatial extent, and meteorological characteristics. The dynamic model RAMS (Regional Atmospheric Modeling System) in the LES (Large Eddy Simulation) mode and the SHDOM (Spherical Harmonic Discrete Ordinate Method) radiative transfer model have been implemented for one particularly long-lived cloud to track the temporal evolution of the cloud halos and to calculate the associated spatial and temporal patterns of shortwave absorption. Results of this modeling study are in general agreement with the field measurement data and previous aircraft studies.

  4. The effect of increased air humidity on fine root and rhizome biomass and turnover of silver birch forest ecosystem - a FAHM study.

    NASA Astrophysics Data System (ADS)

    Ostonen, I.; Kupper, P.; Sõber, J.; Aosaar, J.; Varik, M.; Lõhmus, K.

    2012-04-01

    A facility for free air humidity manipulation (FAHM) was established to investigate the effect of increased air humidity on belowground biomass and turnover in silver birch (Betula pendula Roth.) forest ecosystems with respect to rising air humidity predicted for Northern Europe. Fine root and rhizomes are short-lived and recognized as the most important component contributing to below-ground C fluxes in forests. The FAHM system enables air relative humidity to be increased on average 7 units (%) over the ambient level during mist fumigation. The experimental site contains humidified (H) and control (C) plots; each plot contains sectors with diverse "forest" understory and early successional grasses. The trees were planted in 2006, humidification started in spring 2008, and soil cores to study fine root and rhizome biomass and turnover were taken in 2007, 2009 and 2010. In July 2009, total fine root and rhizome biomass was 8 tons per ha in C and 16 tons per ha in H plots. The roots of understory formed 86% in C and 93% H plots, respectively. Our preliminary data suggest that the increased humidity affected more the roots of understory plants: fine root and rhizome biomass and production increased approximately twice by increasing air humidity. However, the tendency was similar for fine root biomass and production of silver birch. Fine root turnover speeded up for both silver birch and understory roots in H plots. Hence, changes in air humidity can significantly affect forest carbon cycling.

  5. Effect of low air velocities on thermal homeostasis and comfort during exercise at space station operational temperature and humidity

    NASA Technical Reports Server (NTRS)

    Beumer, Ronald J.

    1989-01-01

    The effectiveness of different low air velocities in maintaining thermal comfort and homeostasis during exercise at space station operational temperature and humidity was investigated. Five male subjects exercised on a treadmill for successive ten minute periods at 60, 71, and 83 percent of maximum oxygen consumption at each of four air velocities, 30, 50, 80, and 120 ft/min, at 22 C and 62 percent relative humidity. No consistent trends or statistically significant differences between air velocities were found in body weight loss, sweat accumulation, or changes in rectal, skin, and body temperatures. Occurrence of the smallest body weight loss at 120 ft/min, the largest sweat accumulation at 30 ft/min, and the smallest rise in rectal temperature and the greatest drop in skin temperature at 120 ft/min all suggested more efficient evaporative cooling at the highest velocity. Heat storage at all velocities was evidenced by increased rectal and body temperatures; skin temperatures declined or increased only slightly. Body and rectal temperature increases corresponded with increased perception of warmth and slight thermal discomfort as exercise progressed. At all air velocities, mean thermal perception never exceeded warm and mean discomfort, greatest at 30 ft/min, was categorized at worst as uncomfortable; sensation of thermal neutrality and comfort returned rapidly after cessation of exercise. Suggestions for further elucidation of the effects of low air velocities on thermal comfort and homeostasis include larger numbers of subjects, more extensive skin temperature measurements and more rigorous analysis of the data from this study.

  6. Increased Air Velocity Reduces Thermal and Cardiovascular Strain in Young and Older Males during Humid Exertional Heat Stress.

    PubMed

    Wright Beatty, Heather E; Hardcastle, Stephen G; Boulay, Pierre; Flouris, Andreas D; Kenny, Glen P

    2015-01-01

    Older adults have been reported to have a lower evaporative heat loss capacity than younger adults during exercise when full sweat evaporation is permitted. However, it is unclear how conditions of restricted evaporative and convective heat loss (i.e., high humidity, clothing insulation) alter heat stress. to the purpose of this study was to examine the heat stress responses of young and older males during and following exercise in a warm/humid environment under two different levels of air velocity. Ten young (YOUNG: 24±2 yr) and 10 older (OLDER: 59±3 yr) males, matched for body surface area performed 4×15-min cycling bouts (15-min rest) at a fixed rate of heat production (400 W) in warm/humid conditions (35°C, 60% relative humidity) under 0.5 (Low) and 3.0 (High) m·s(-1) air velocity while wearing work coveralls. Rectal (Tre) and mean skin (MTsk) temperatures, heart rate (HR), local sweat rate, % max skin blood flow (SkBF) (recovery only), and blood pressure (recovery only) were measured. High air velocity reduced core and skin temperatures (p < 0.05) equally in YOUNG and OLDER males (p > 0.05) but was more effective in reducing cardiovascular strain (absolute and % max HR; p < 0.05) in YOUNG males (p < 0.05). Greater increases in local dry heat loss responses (% max SkBF and cutaneous vascular conductance) were detected across time in OLDER than YOUNG males in both conditions (p < 0.05). Local dry heat loss responses and cardiovascular strain were attenuated during the High condition in YOUNG compared to OLDER (p < 0.05). High air velocity reduced the number of males surpassing the 38.0°C Tre threshold from 90% (Low) to 50% (High). Despite age-related local heat loss differences, YOUNG and OLDER males had similar levels of heat stress during intermittent exercise in warm and humid conditions while wearing work coveralls. Increased air velocity was effective in reducing heat stress equally, and cardiovascular strain to a greater extent, in YOUNG and OLDER

  7. Estimation of spatial variability in humidity, wind, and solar radiation using the random forest algorithm for the conterminous USA

    NASA Astrophysics Data System (ADS)

    Hashimoto, H.; Nemani, R. R.

    2015-12-01

    Regional scale ecosystem modeling requires high-resolution data of surface climate variables. Spatial variability in temperature and precipitation has been well studied over the past two decades resulting in several sophisticated algorithms. However, compared to temperature and precipitation, other surface climate variables, such as humidity, solar radiation and wind speed, are not available to use, even though those data are equally important for ecosystem modeling. The main reason for this is the lack of governing physical equations for interpolating observations and the lack of comparable satellite observations. Therefore, scientists have been using reanalysis data or simply interpolated data for ecosystem modeling, though they are too coarse for regional scale ecosystem analysis. In this study, we developed a method to spatially map daily climate variables, including humidity, solar radiation, wind, precipitation, and temperature. We applied the method to the conterminous USA from 1980 to 2015. Previously, we successfully developed a precipitation interpolation method using random forest algorithm, and now we extended it to the other variables. Because this method does not require any assumptions about physical equations, this method can potentially be applicable to any climate variable if measured data are available. The method requires point data along with a host of spatial data sets . Satellite data, reanalysis data, and radar data were used and the importance of each dataset was analyzed using random forest algorithm. The only parameter we need to adjust is the radius from the target point, in which statistically meaningful relationships between observed and spatial co-variate data is calculated. The radius was optimized using mean absolute error and bias. We also analyzed temporal consistency and spatial patterns of the results. Because it is relatively easy to customize the setup depending on user's request, the resulting datasets may be useful for

  8. On water repellency, humidity, fire, and wind erosion in arid landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies of water repellent soils have usually focused on their effect on infiltration and runoff. In arid regions, however, the landscape is often shaped more by wind than by water, with important implications for ecology and land management. In a series of field, laboratory, and theoretical experim...

  9. Wind Direction Bias in Generating Wind Roses and Conducting Sector-Based Air-Dispersion Modeling

    SciTech Connect

    Droppo, James G.; Napier, Bruce A.

    2008-07-01

    Certain widely used wind rose programs and air dispersion models use an overly-simple data-transfer algorithm that induces a directional bias in their output products. The purpose of this paper is to provide a revised algorithm that corrects the aliasing bias that occurs when the internals in reported wind direction data are on the same order of magnitude, but not equal to the intervals used in the wind direction summaries. The directional bias issue arises when output products in 22.5-degree sectors are produced from 10-degree wind direction data, which affects the results of simulations of air and surface concentrations using widely applied air-dispersion models. Datasets or models with the bias discussed here give consistent positive biases (approximately 30%) for cardinal direction sectors (north, south, east, and west) and consistent negative biases for all the other sectors (approximately -10%). Data summary and air dispersion programs providing outputs in directions sectors that do not match the observational sectors need to be checked for this bias. A revised data-transfer algorithm is provided that corrects the aliasing bias that can occur in transferring wind direction data between different sectors widths.

  10. Predicting Indian Summer Monsoon onset through variations of surface air temperature and relative humidity

    NASA Astrophysics Data System (ADS)

    Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

    2015-04-01

    Indian Summer Monsoon (ISM) rainfall has an enormous effect on Indian agriculture, economy, and, as a consequence, life and prosperity of more than one billion people. Variability of the monsoonal rainfall and its onset have a huge influence on food production, agricultural planning and GDP of the country, which on 22% is determined by agriculture. Consequently, successful forecasting of the ISM onset is a big challenge and large efforts are being put into it. Here, we propose a novel approach for predictability of the ISM onset, based on critical transition theory. The ISM onset is defined as an abrupt transition from sporadious rainfall to spatially organized and temporally sustained rainfall. Taking this into account, we consider the ISM onset as is a critical transition from pre-monsoon to monsoon, which take place in time and also in space. It allows us to suggest that before the onset of ISM on the Indian subcontinent should be areas of critical behavior where indicators of the critical transitions can be detected through an analysis of observational data. First, we identify areas with such critical behavior. Second, we use detected areas as reference points for observation locations for the ISM onset prediction. Third, we derive a precursor for the ISM onset based on the analysis of surface air temperature and relative humidity variations in these reference points. Finally, we demonstrate the performance of this precursor on two observational data sets. The proposed approach allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. The ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In the anomalous years, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the

  11. EDITORIAL: Humidity sensors Humidity sensors

    NASA Astrophysics Data System (ADS)

    Regtien, Paul P. L.

    2012-01-01

    All matter is more or less hygroscopic. The moisture content varies with vapour concentration of the surrounding air and, as a consequence, most material properties change with humidity. Mechanical and thermal properties of many materials, such as the tensile strength of adhesives, stiffness of plastics, stoutness of building and packaging materials or the thermal resistivity of isolation materials, all decrease with increasing environmental humidity or cyclic humidity changes. The presence of water vapour may have a detrimental influence on many electrical constructions and systems exposed to humid air, from high-power systems to microcircuits. Water vapour penetrates through coatings, cable insulations and integrated-circuit packages, exerting a fatal influence on the performance of the enclosed systems. For these and many other applications, knowledge of the relationship between moisture content or humidity and material properties or system behaviour is indispensable. This requires hygrometers for process control or test and calibration chambers with high accuracy in the appropriate temperature and humidity range. Humidity measurement methods can roughly be categorized into four groups: water vapour removal (the mass before and after removal is measured); saturation (the air is brought to saturation and the `effort' to reach that state is measured); humidity-dependent parameters (measurement of properties of humid air with a known relation between a specific property and the vapour content, for instance the refractive index, electromagnetic spectrum and acoustic velocity); and absorption (based on the known relation between characteristic properties of non-hydrophobic materials and the amount of absorbed water from the gas to which these materials are exposed). The many basic principles to measure air humidity are described in, for instance, the extensive compilations by Wexler [1] and Sonntag [2]. Absorption-type hygrometers have small dimensions and can be

  12. Effect of inlet-air humidity, temperature, pressure, and reference Mach number on the formation of oxides of nitrogen in a gas turbine combustor

    NASA Technical Reports Server (NTRS)

    Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

    1973-01-01

    Tests were conducted to determine the effect of inlet air humidity on the formation of oxides of nitrogen (NOx) from a gas turbine combustor. Combustor inlet air temperature ranged from 506 K (450 F) to 838 K (1050 F). The tests were primarily run at a constant pressure of 6 atmospheres and reference Mach number of 0.065. The NOx emission index was found to decrease with increasing inlet air humidity at a constant exponential rate: NOx = NOx0e-19H (where H is the humidity and the subscript 0 denotes the value at zero humidity). the emission index increased exponentially with increasing normalized inlet air temperature to the 1.14 power. Additional tests made to determine the effect of pressure and reference Mach number on NOx showed that the NOx emission index varies directly with pressure to the 0.5 power and inversely with reference Mach number.

  13. Thermal comfort in air-conditioned buildings in hot and humid climates--why are we not getting it right?

    PubMed

    Sekhar, S C

    2016-02-01

    While there are plenty of anecdotal experiences of overcooled buildings in summer, evidence from field studies suggests that there is indeed an issue of overcooling in tropical buildings. The findings suggest that overcooled buildings are not a consequence of occupant preference but more like an outcome of the HVAC system design and operation. Occupants' adaptation in overcooled indoor environments through additional clothing cannot be regarded as an effective mitigating strategy for cold thermal discomfort. In the last two decades or so, several field studies and field environmental chamber studies in the tropics provided evidence for occupants' preference for a warmer temperature with adaptation methods such as elevated air speeds. It is important to bear in mind that indoor humidity levels are not compromised as they could have an impact on the inhaled air condition that could eventually affect perceived air quality. This review article has attempted to track significant developments in our understanding of the thermal comfort issues in air-conditioned office and educational buildings in hot and humid climates in the last 25 years, primarily on occupant preference for thermal comfort in such climates. The issue of overcooled buildings, by design intent or otherwise, is discussed in some detail. Finally, the article has explored some viable adaptive thermal comfort options that show considerable promise for not only improving thermal comfort in tropical buildings but are also energy efficient and could be seen as sustainable solutions. PMID:25626476

  14. Effects of 6-h exposure to low relative humidity and low air pressure on body fluid loss and blood viscosity.

    PubMed

    Hashiguchi, N; Takeda, A; Yasuyama, Y; Chishaki, A; Tochihara, Y

    2013-10-01

    The purpose of this study was to investigate the effects of 6-h exposure to low relative humidity (RH) and low air pressure in a simulated air cabin environment on body fluid loss (BFL) and blood viscosity. Fourteen young healthy male subjects were exposed to four conditions, which combined RH (10% RH or 60% RH) and air pressure (NP: sea level or LP: equivalent to an altitude of 2000 m). Subjects remained seated on a chair in the chamber for 6 h. Their diet and water intake were restricted before and during the experiment. Insensible water loss (IWL) in LP10% condition was significantly greater than in NP60% condition; thus, combined 10%RH and LP conditions promoted a greater amount of IWL. The BFL under the LP condition was significantly greater than that under the NP condition. Blood viscosity significantly increased under LP conditions. Increases in red blood cell counts (RBCs) and BFL likely contributed to the increased blood viscosity. These findings suggest that hypobaric-induced hypoxia, similar to the conditions in the air cabin environment, may cause increased blood viscosity and that the combined low humidity and hypobaric hypoxia conditions increase IWL. PMID:23464811

  15. High resolution vertical profiles of wind, temperature and humidity obtained by computer processing and digital filtering of radiosonde and radar tracking data from the ITCZ experiment of 1977

    NASA Technical Reports Server (NTRS)

    Danielson, E. F.; Hipskind, R. S.; Gaines, S. E.

    1980-01-01

    Results are presented from computer processing and digital filtering of radiosonde and radar tracking data obtained during the ITCZ experiment when coordinated measurements were taken daily over a 16 day period across the Panama Canal Zone. The temperature relative humidity and wind velocity profiles are discussed.

  16. Measurement and Modeling of Vertical Temperature, Humidity and Wind Profiles Through Aspen Stands in a Mountain Basin

    NASA Astrophysics Data System (ADS)

    Flerchinger, G. N.; Marks, D. G.; Reba, M. L.; Link, T. E.

    2013-12-01

    Forest canopies filter climate by reducing wind speed and solar radiation, and moderating temperature and thermal radiation to the ground surface. Vertical profiles were established in two aspen stands to investigate how deciduous canopy structure modulates interaction between the atmosphere and the snow or soil surface below the canopy. The study sites are located within Reynolds Creek Experimental Watershed (RCEW) at the Reynolds Mountain East (RME) and Upper Sheep Creek (USC) catchments. The aspen canopy at RME is 15 m tall and that at USC is 4.5 m. For this study, meteorological sensors were placed on a tower at 3, 9, and 15 m above the ground surface for the RME site and at 1.5, 3.0 and 4.5 m at the USC site. The data presented include hourly averages of temperature, humidity, wind speed, and vegetation surface temperature at each level. Inter-annual, seasonal, monthly and diurnal variability are reported. Analysis of events during key periods of interest, including snow covered, meltout, and snow-free growing season periods are also reported. Precipitation, solar and thermal radiation, soil temperature and soil moisture data from nearby stations within the catchments were used to support the analysis and to model the canopy profile data. This analysis illustrates the sensitivity of surface energetics and watershed hydrology to canopy structure.

  17. Energy impact of various inside air temperatures and humidities in a museum when located in five U. S. cities

    SciTech Connect

    Ayres, J.M.; Lau, H.; Haiad, J.C. )

    1990-01-01

    The art conservation literature presents a wide range of recommended temperatures and relative humidities required to protect the safety of collections in museums, but the operating energy costs for specific criteria have not been identified. The Scott Gallery at the Huntington Library and Art Gallery in San Marino, CA, was selected for a detailed study of energy costs associated with recommended environmental levels for museums. The results of computer simulations of the Scott Gallery when located in Albuquerque, NM; Burbank, CA; Minneapolis, MN; New Orleans, LA; and New York, NY are presented. The simulations were performed suing the DOE-2 building energy analysis computer program. The peak heating and cooling load components are identified, thermal zone loads quantified, and psychrometric analysis of the annual energy requirements with fixed and variable inside air temperature and relative humidity (RH) setpoints are presented. In all five climate regions the minimum energy consumption occurred with a 70 {degree} F and 50% RH setpoint.

  18. Wind Energy and Air Emission Reduction Benefits: A Primer

    SciTech Connect

    Jacobson, D.; High, C.

    2008-02-01

    This document provides a summary of the impact of wind energy development on various air pollutants for a general audience. The core document addresses the key facts relating to the analysis of emission reductions from wind energy development. It is intended for use by a wide variety of parties with an interest in this issue, ranging from state environmental officials to renewable energy stakeholders. The appendices provide basic background information for the general reader, as well as detailed information for those seeking a more in-depth discussion of various topics.

  19. Induced Air Movement for Wide-Span Schools in Humid Asia. Educational Building Digest 9.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and Oceania.

    Schools in the hot and humid zones of the Asian region are narrow to ensure good ventilation. The purpose of this report is to show that it is possible, through appropriate design, to obtain sufficient breeze for thermal comfort in buildings as wide as 15 meters. Some of the conclusions of a study of the subject are summarized. The summary is…

  20. Membrane Dehumidifier: High-Efficiency, On-Line Membrane Air Dehumidifier Enabling Sensible Cooling for Warm and Humid Climates

    SciTech Connect

    2010-09-01

    BEETIT Project: ADMA Products is developing a foil-like membrane for air conditioners that efficiently removes moisture from humid air. ADMA Products’s metal foil-like membrane consists of a paper thin, porous metal sheet coated with a layer of water-loving molecules. This new membrane allows water vapor to permeate across the membrane at high fluxes and at the same time, blocks air penetration efficiently resulting in high selectivity. The high selectivity of the membrane translates to less energy use, while the high permeation fluxes result in a more compact device. The new materials and the flat foil-like nature of the membrane facilitate the mass production of a low-coast compact dehumidification device

  1. Air temperature and humidity diversity in the Hornsund fjord area (Spitsbergen) in the period 1 July 2014 - 30 June 2015

    NASA Astrophysics Data System (ADS)

    Przybylak, Rajmund; Araźny, Andrzej; Wyszyński, Przemysław; Budzik, Tomasz; Wawrzyniak, Tomasz

    2016-04-01

    The article presents preliminary results of studies into the spatial diversity of air temperature and relative humidity (overground layer, 2 m a.g.l.) in the area of the Hornsund fjord (S Spitsbergen, approx. 77°N), based on data collected between 1 July 2014 and 30 June 2015. The Hornsund fjord runs latitudinal along approx. 40 km and its average width is about 10 km. Numerous glaciers flow into the fjord and the mountain ridges around it often exceed 700 m a.s.l. Data series obtained from 11 sites equipped with automatic weather stations (Vaisala, Campbell, Davis) or HOBO temperature and humidity sensors were used. Two sites (Hornsund HOR and the Hans Glacier HG4) have been operating for years, whereas 9 new ones (Bogstranda BOG, Fugleberget FUG, Gnålodden GNA, Gåshamnoyra GAS, Hyttevika HYT, Lisbetdalen LIS, Ostrogradskijfjella OST, Treskelodden TRE and Wilczekodden WIL) were established within the Polish-Norwegian AWAKE-2 project. Three of the sites (BOG, GAS and OST) were damaged by polar bears, hence their measurement series are shorter. A substantial spatial diversity was found in the air temperature and relative humidity in the area, mostly influenced by elevation, type of surface and distance from the Greenland Sea's open water. During the year (July 2014 - June 2015), the areas of HYT (-1.1°C) and WIL (-1.9°C) were the warmest. Both sites are located on the west coast of the fjord. The HYT demonstrates the most favourable temperature conditions, being orographically sheltered from the east and its cold and dry air masses. The coldest sites were the mountain-top site of FUG (-5.9°C) and the glacier-located HG4 (-4.3°C). The low temperature at FUG resulted from its elevation (568 m a.s.l.), whereas at HG4 (184 m a.s.l) the glaciated surface also added up to the result. In the analysed period, the annual course of air temperature in the area had a clear minimum in February, when the lowest mean monthly values ranged from -9.4°C at HYT to -15.1°C at

  2. Determination of benzene, toluene and xylene concentration in humid air using differential ion mobility spectrometry and partial least squares regression.

    PubMed

    Maziejuk, M; Szczurek, A; Maciejewska, M; Pietrucha, T; Szyposzyńska, M

    2016-05-15

    Benzene, toluene and xylene (BTX compounds) are chemicals of greatest concern due to their impact on humans and the environment. In many cases, quantitative information about each of these compounds is required. Continuous, fast-response analysis, performed on site would be desired for this purpose. Several methods have been developed to detect and quantify these compounds in this way. Methods vary considerably in sensitivity, accuracy, ease of use and cost-effectiveness. The aim of this work is to show that differential ion mobility spectrometry (DMS) may be applied for determining concentration of BTX compounds in humid air. We demonstrate, this goal is achievable by applying multivariate analysis of the measurement data using partial least squares (PLS) regression. The approach was tested at low concentrations of these compounds in the range of 5-20ppm and for air humidity in a range 0-12g/kg. These conditions correspond to the foreseeable application of the developed approach in occupational health and safety measurements. The average concentration assessment error was about 1ppm for each: benzene, toluene and xylene. We also successfully determined water vapor content in air. The error achieved was 0.2g/kg. The obtained results are very promising regarding further development of DMS technique as well as its application. PMID:26992504

  3. Within-Crop Air Temperature and Humidity Outcomes on Spatio-Temporal Distribution of the Key Rose Pest Frankliniella occidentalis.

    PubMed

    Fatnassi, Hicham; Pizzol, Jeannine; Senoussi, Rachid; Biondi, Antonio; Desneux, Nicolas; Poncet, Christine; Boulard, Thierry

    2015-01-01

    Frankliniella occidentalis (Pergande) is a key pest of various crops worldwide. In this study, we analyse the dependence of the infestation of this pest on spatially distributed micro climatic factors in a rose greenhouse. Despite the importance of this subject, the few existing studies have been realized in laboratory rather than in greenhouse conditions. However, recent progress on greenhouse microclimate characterisation has highlighted the strong indoor climate heterogeneity that may influence the within-crop pest distribution. In this study, both microclimate (air temperature and humidity) and thrips distribution were simultaneously mapped in a rose greenhouse. The measurements were sensed in a horizontal plane situated at mid-height of the rose crop inside the greenhouse. Simultaneously, thrips population dynamics were assessed after an artificial and homogeneous infestation of the rose crop. The spatio-temporal distribution of climate and thrips within the greenhouse were compared, and links between thrips infestation and climatic conditions were investigated. A statistical model was used to define the favourable climate conditions for thrips adults and larvae. Our results showed that (i) the air temperature and air humidity were very heterogeneously distributed within the crop, (ii) pest populations aggregated in the most favourable climatic areas and (iii) the highest population density of thrips adults and larvae were recorded at 27°C and 22°C for temperature and 63% and 86% for humidity, respectively. These findings confirm, in real rose cropping conditions, previous laboratory studies on the F. occidentalis climatic optimum and provide a solid scientific support for climatic-based control methods against this pest. PMID:26011275

  4. Within-Crop Air Temperature and Humidity Outcomes on Spatio-Temporal Distribution of the Key Rose Pest Frankliniella occidentalis

    PubMed Central

    Fatnassi, Hicham; Pizzol, Jeannine; Senoussi, Rachid; Biondi, Antonio; Desneux, Nicolas; Poncet, Christine; Boulard, Thierry

    2015-01-01

    Frankliniella occidentalis (Pergande) is a key pest of various crops worldwide. In this study, we analyse the dependence of the infestation of this pest on spatially distributed micro climatic factors in a rose greenhouse. Despite the importance of this subject, the few existing studies have been realized in laboratory rather than in greenhouse conditions. However, recent progress on greenhouse microclimate characterisation has highlighted the strong indoor climate heterogeneity that may influence the within-crop pest distribution. In this study, both microclimate (air temperature and humidity) and thrips distribution were simultaneously mapped in a rose greenhouse. The measurements were sensed in a horizontal plane situated at mid-height of the rose crop inside the greenhouse. Simultaneously, thrips population dynamics were assessed after an artificial and homogeneous infestation of the rose crop. The spatio-temporal distribution of climate and thrips within the greenhouse were compared, and links between thrips infestation and climatic conditions were investigated. A statistical model was used to define the favourable climate conditions for thrips adults and larvae. Our results showed that (i) the air temperature and air humidity were very heterogeneously distributed within the crop, (ii) pest populations aggregated in the most favourable climatic areas and (iii) the highest population density of thrips adults and larvae were recorded at 27°C and 22°C for temperature and 63% and 86% for humidity, respectively. These findings confirm, in real rose cropping conditions, previous laboratory studies on the F. occidentalis climatic optimum and provide a solid scientific support for climatic-based control methods against this pest. PMID:26011275

  5. Unexpected luminescent and quenching properties of metalloporphyrins in Langmuir-Blodgett structures: application to relative air-humidity sensing

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitry B.; Ponomarev, Gely V.; Chernov, Sergey F.; Kurochkin, Ilya N.

    1993-05-01

    Monomolecular thin solid films containing water-soluble Pt- and Pd-porphyrins were prepared and transferred onto solid supports. Surface active charged polymer on the basis of alkylated polyethyleneimine was used to improve extraction of the dye from aqueous solution to the interface. The solid-state materials obtained which showed intense long-decay luminescence were studied by optical methods with emphasis to luminescence quenching and lifetime measurements. The results were applied to quenched-luminescence lifetime-based sensing of relative air humidity. A corresponding fiber-optic prototype device was developed.

  6. Effects of ambient air temperature, humidity and rainfall on annual survival of adult little penguins Eudyptula minor in southeastern Australia.

    PubMed

    Ganendran, L B; Sidhu, L A; Catchpole, E A; Chambers, L E; Dann, P

    2016-08-01

    Seabirds are subject to the influences of local climate variables during periods of land-based activities such as breeding and, for some species, moult; particularly if they undergo a catastrophic moult (complete simultaneous moult) as do penguins. We investigated potential relationships between adult penguin survival and land-based climate variables (ambient air temperature, humidity and rainfall) using 46 years of mark-recapture data of little penguins Eudyptula minor gathered at a breeding colony on Phillip Island in southeastern Australia. Our results showed that adult penguin survival had a stronger association with land-based climate variables during the moult period, when birds were unable to go to sea for up to 3 weeks, than during the breeding period, when birds could sacrifice breeding success in favour of survival. Annual adult survival probability was positively associated with humidity during moult and negatively associated with rainfall during moult. Prolonged heat during breeding and moult had a negative association with annual adult survival. Local climate projections suggest increasing days of high temperatures, fewer days of rainfall which will result in more droughts (and by implication, lower humidity) and more extreme rainfall events. All of these predicted climate changes are expected to have a negative impact on adult penguin survival. PMID:26698160

  7. Effects of ambient air temperature, humidity and rainfall on annual survival of adult little penguins Eudyptula minor in southeastern Australia

    NASA Astrophysics Data System (ADS)

    Ganendran, L. B.; Sidhu, L. A.; Catchpole, E. A.; Chambers, L. E.; Dann, P.

    2015-12-01

    Seabirds are subject to the influences of local climate variables during periods of land-based activities such as breeding and, for some species, moult; particularly if they undergo a catastrophic moult (complete simultaneous moult) as do penguins. We investigated potential relationships between adult penguin survival and land-based climate variables (ambient air temperature, humidity and rainfall) using 46 years of mark-recapture data of little penguins Eudyptula minor gathered at a breeding colony on Phillip Island in southeastern Australia. Our results showed that adult penguin survival had a stronger association with land-based climate variables during the moult period, when birds were unable to go to sea for up to 3 weeks, than during the breeding period, when birds could sacrifice breeding success in favour of survival. Annual adult survival probability was positively associated with humidity during moult and negatively associated with rainfall during moult. Prolonged heat during breeding and moult had a negative association with annual adult survival. Local climate projections suggest increasing days of high temperatures, fewer days of rainfall which will result in more droughts (and by implication, lower humidity) and more extreme rainfall events. All of these predicted climate changes are expected to have a negative impact on adult penguin survival.

  8. Effects of ambient air temperature, humidity and rainfall on annual survival of adult little penguins Eudyptula minor in southeastern Australia

    NASA Astrophysics Data System (ADS)

    Ganendran, L. B.; Sidhu, L. A.; Catchpole, E. A.; Chambers, L. E.; Dann, P.

    2016-08-01

    Seabirds are subject to the influences of local climate variables during periods of land-based activities such as breeding and, for some species, moult; particularly if they undergo a catastrophic moult (complete simultaneous moult) as do penguins. We investigated potential relationships between adult penguin survival and land-based climate variables (ambient air temperature, humidity and rainfall) using 46 years of mark-recapture data of little penguins Eudyptula minor gathered at a breeding colony on Phillip Island in southeastern Australia. Our results showed that adult penguin survival had a stronger association with land-based climate variables during the moult period, when birds were unable to go to sea for up to 3 weeks, than during the breeding period, when birds could sacrifice breeding success in favour of survival. Annual adult survival probability was positively associated with humidity during moult and negatively associated with rainfall during moult. Prolonged heat during breeding and moult had a negative association with annual adult survival. Local climate projections suggest increasing days of high temperatures, fewer days of rainfall which will result in more droughts (and by implication, lower humidity) and more extreme rainfall events. All of these predicted climate changes are expected to have a negative impact on adult penguin survival.

  9. Quantitative Ethylene Measurements with MOx Chemiresistive Sensors at Different Relative Air Humidities

    PubMed Central

    Krivec, Matic; Mc Gunnigle, Gerald; Abram, Anže; Maier, Dieter; Waldner, Roland; Gostner, Johanna M.; Überall, Florian; Leitner, Raimund

    2015-01-01

    The sensitivity of two commercial metal oxide (MOx) sensors to ethylene is tested at different relative humidities. One sensor (MiCS-5914) is based on tungsten oxide, the other (MQ-3) on tin oxide. Both sensors were found to be sensitive to ethylene concentrations down to 10 ppm. Both sensors have significant response times; however, the tungsten sensor is the faster one. Sensor models are developed that predict the concentration of ethylene given the sensor output and the relative humidity. The MQ-3 sensor model achieves an accuracy of ±9.2 ppm and the MiCS-5914 sensor model predicts concentration to ±7.0 ppm. Both sensors are more accurate for concentrations below 50 ppm, achieving ±6.7 ppm (MQ-3) and 5.7 ppm (MiCS-5914). PMID:26561812

  10. Heating, Ventilation, and Air Conditioning Design Strategy for a Hot-Humid Production Builder

    SciTech Connect

    Kerrigan, P.

    2014-03-01

    Building Science Corporation (BSC) worked directly with the David Weekley Homes - Houston division to develop a cost-effective design for moving the HVAC system into conditioned space. In addition, BSC conducted energy analysis to calculate the most economical strategy for increasing the energy performance of future production houses in preparation for the upcoming code changes in 2015. This research project addressed the following questions: 1. What is the most cost effective, best performing and most easily replicable method of locating ducts inside conditioned space for a hot-humid production home builder that constructs one and two story single family detached residences? 2. What is a cost effective and practical method of achieving 50% source energy savings vs. the 2006 International Energy Conservation Code for a hot-humid production builder? 3. How accurate are the pre-construction whole house cost estimates compared to confirmed post construction actual cost?

  11. Quantitative Ethylene Measurements with MOx Chemiresistive Sensors at Different Relative Air Humidities.

    PubMed

    Krivec, Matic; Mc Gunnigle, Gerald; Abram, Anže; Maier, Dieter; Waldner, Roland; Gostner, Johanna M; Überall, Florian; Leitner, Raimund

    2015-01-01

    The sensitivity of two commercial metal oxide (MOx) sensors to ethylene is tested at different relative humidities. One sensor (MiCS-5914) is based on tungsten oxide, the other (MQ-3) on tin oxide. Both sensors were found to be sensitive to ethylene concentrations down to 10 ppm. Both sensors have significant response times; however, the tungsten sensor is the faster one. Sensor models are developed that predict the concentration of ethylene given the sensor output and the relative humidity. The MQ-3 sensor model achieves an accuracy of ±9.2 ppm and the MiCS-5914 sensor model predicts concentration to ±7.0 ppm. Both sensors are more accurate for concentrations below 50 ppm, achieving ±6.7 ppm (MQ-3) and 5.7 ppm (MiCS-5914). PMID:26561812

  12. Imaging of Biological Macromolecules on Mica in Humid Air by Scanning Electrochemical Microscopy

    NASA Astrophysics Data System (ADS)

    Fan, Fu-Ren F.; Bard, Allen J.

    1999-12-01

    Imaging of DNA, keyhole limpet hemocyanin, mouse monoclonal IgG, and glucose oxidase on a mica substrate has been accomplished by scanning electrochemical microscopy with a tungsten tip. The technique requires the use of a high relative humidity to form a thin film of water on the mica surface that allows electrochemical reactions to take place at the tip and produce a faradaic current (≈ 1\\ pA) that can be used to control tip position. The effect of relative humidity and surface pretreatment with buffer solutions on the ionic conductivity of a mica surface was investigated to find appropriate conditions for imaging. Resolution of the order of 1 nm was obtained.

  13. Imaging of biological macromolecules on mica in humid air by scanning electrochemical microscopy

    PubMed Central

    Fan, Fu-Ren F.; Bard, Allen J.

    1999-01-01

    Imaging of DNA, keyhole limpet hemocyanin, mouse monoclonal IgG, and glucose oxidase on a mica substrate has been accomplished by scanning electrochemical microscopy with a tungsten tip. The technique requires the use of a high relative humidity to form a thin film of water on the mica surface that allows electrochemical reactions to take place at the tip and produce a faradaic current (≈1 pA) that can be used to control tip position. The effect of relative humidity and surface pretreatment with buffer solutions on the ionic conductivity of a mica surface was investigated to find appropriate conditions for imaging. Resolution of the order of 1 nm was obtained. PMID:10588687

  14. Investigating In-cloud Relative Humidity and Thin Cirrus in the Upper Tropical Atmosphere Using AIRS, CALIPSO, and MLS

    NASA Astrophysics Data System (ADS)

    Liang, C. K.; Kahn, B. H.; Eldering, A.; Fetzer, E. J.

    2007-12-01

    We investigate vertical and horizontal distributions of tropical oceanic thin cirrus optical and microphysical properties observed by the Atmospheric Infrared Sounder (AIRS). These properties are related to thermodynamic quantities, i.e., relative humidity with respect to ice (RHi), and cloud top temperature derived from the AIRS Level 2 operational soundings. Differences between all sky and in-cloud RHi are explored and possible mechanisms that explain these anomalies are discussed. Furthermore, we evaluate the hypothesis that many of the observed clouds are physically much thinner than the nominal resolution of AIRS, which may lead to dry biases of in-cloud RHi. To test this we exploit the co-located AIRS RHi and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) cloud thickness. Finally, we diagnose the ability of AIRS to measure water vapor in the Tropical Tropopause Layer (TTL) using co- located observations from the Microwave Limb Sounder (MLS). From this, a combined AIRS-MLS RHi product is used to investigate joint distributions of cirrus microphysical and optical properties, and RHi in the TTL.

  15. Air-flow separation over unsteady breaking wind waves

    NASA Astrophysics Data System (ADS)

    Saxena, Gaurav

    2005-11-01

    In air-sea interaction processes, when considering wind stress over small-scale breaking waves, there are few direct quantitative experimental investigations into the role of air-flow separation on the interfacial momentum flux. Reul et. al, (1999), found multiple coherent patches of vorticity downwind of the crest that were strongly influenced by the geometric characteristics of the breaker. However, their breakers were generated by dispersive focusing techniques and, therefore, independent of the wind stress. We present experimental results obtained with particle image velocimetry (PIV) where moderate to strong winds directly generate unsteady small-scale breaking waves, a scenario commonly found in the open ocean. Particular attention has been devoted to capturing the spatio-temporal evolution of the air-water interface. Specifically, texture segmentation algorithms typically used for face recognition (Grey Level Co-occurrence Matrix (GLCM) and the Cross-Diagonal Texture Matrix (CDTM)) have been combined to yield robust and accurate estimates of the instantaneous breaker geometry.

  16. Integration of Wind Turbines with Compressed Air Energy Storage

    NASA Astrophysics Data System (ADS)

    Arsie, I.; Marano, V.; Rizzo, G.; Moran, M.

    2009-08-01

    Some of the major limitations of renewable energy sources are represented by their low power density and intermittent nature, largely depending upon local site and unpredictable weather conditions. These problems concur to increase the unit costs of wind power, so limiting their diffusion. By coupling storage systems with a wind farm, some of the major limitations of wind power, such as a low power density and an unpredictable nature, can be overcome. After an overview on storage systems, the Compressed Air Energy Storage (CAES) is analyzed, and the state of art on such systems is discussed. A Matlab/Simulink model of a hybrid power plant consisting of a wind farm coupled with CAES is then presented. The model has been successfully validated starting from the operating data of the McIntosh CAES Plant in Alabama. Time-series neural network-based wind speed forecasting are employed to determine the optimal daily operation strategy for the storage system. A detailed economic analysis has been carried out: investment and maintenance costs are estimated based on literature data, while operational costs and revenues are calculated according to energy market prices. As shown in the paper, the knowledge of the expected available energy is a key factor to optimize the management strategies of the proposed hybrid power plant, allowing to obtain environmental and economic benefits.

  17. Apparatus for supplying conditioned air at a substantially constant temperature and humidity

    NASA Technical Reports Server (NTRS)

    Obler, H. D. (Inventor)

    1980-01-01

    The apparatus includes a supply duct coupled to a source of supply air for carrying the supply air therethrough. A return duct is coupled to the supply duct for carrying return conditioned air therethrough. A temperature reducing device is coupled to the supply duct for decreasing the temperature of the supply and return conditioned air. A by-pass duct is coupled to the supply duct for selectively directing portions of the supply and return conditioned air around the temperature reducing device. Another by-pass duct is coupled to the return duct for selectively directing portions of the return conditioned air around the supply duct and the temperature reduction device. Controller devices selectively control the flow and amount of mixing of the supply and return conditioned air.

  18. Cost benefit analysis and energy savings of using compression and absorption chillers for air conditioners in hot and humid climates

    NASA Astrophysics Data System (ADS)

    Shekarchian, M.; Moghavvemi, M.; Motasemi, F.; Mahlia, T. M. I.

    2012-06-01

    The electricity consumption growth has increased steadily in the recent decade which is a great concern for the environment. Increasing the number of high-rise air-conditioned buildings and the rapid use of electrical appliances in residential and commercial sectors are two important factors for high electricity consumption. This paper investigates the annual energy required for cooling per unit area and the total energy cost per unit area for each type of air conditioning systems in hot and humid climates. The effects of changing the coefficient of performance (COP) of absorption chillers on cost saving was also investigated in this study. The results showed that using absorption chillers for cooling will increase the amount of energy consumption per unit area; however the energy cost per unit area will decrease. In addition this research indicates that for each 0.1 increment in COP of absorption chillers, there is about 500 USD/m2 saved cost.

  19. The Relationship between Relative Humidity and the Dewpoint Temperature in Moist Air: A Simple Conversion and Applications.

    NASA Astrophysics Data System (ADS)

    Lawrence, Mark G.

    2005-02-01

    The relative humidity (RH) and the dewpoint temperature (td) are two widely used indicators of the amount of moisture in air. The exact conversion from RH to td, as well as highly accurate approximations, are too complex to be done easily without the help of a calculator or computer. However, there is a very simple rule of thumb that can be very useful for approximating the conversion for moist air (RH > 50%) which does not appear to be widely known by the meteorological community: td decreases by about 1°C for every 5% decrease in RH (starting at td = t, the dry bulb temperature, when RH = 100%). This article examines the mathematical basis and accuracy of this and other relationships between the dewpoint and relative humidity. Several useful applications of the simple conversion are presented, in particular the computation of the cumulus cloud-base level (or lifting condensation level) as zLCL (20 + t/5) (100 - RH), where zLCL is in meters when t is in degrees Celcius and RH in percent. Finally, a historical perspective is given with anecdotes about some of the early work in this field.

  20. An integrated evaluation of thirteen modelling solutions for the generation of hourly values of air relative humidity

    NASA Astrophysics Data System (ADS)

    Bregaglio, Simone; Donatelli, Marcello; Confalonieri, Roberto; Acutis, Marco; Orlandini, Simone

    2010-11-01

    The availability of hourly air relative humidity (HARH) data is a key requirement for the estimation of epidemic dynamics of plant fungal pathogens, in particular for the simulation of both the germination of the spores and the infection process. Most of the existing epidemic forecasting models require these data as input directly or indirectly, in the latter case for the estimation of leaf wetness duration. In many cases, HARH must be generated because it is not available in historical series and when there is the need to simulate epidemics either on a wide scale or with different climate scenarios. Thirteen modelling solutions (MS) for the generation of this variable were evaluated, with different input requirements and alternative approaches, on a large dataset including several sites and years. A composite indicator was developed using fuzzy logic to compare and to evaluate the performances of the models. The indicator consists of four modules: Accuracy, Correlation, Pattern and Robustness. Results showed that when available, daily maximum and minimum air relative humidity data substantially improved the estimation of HARH. When such data are not available, the choice of the MS is crucial, given the difference in predicting skills obtained during the analysis, which allowed a clear detection of the best performing MS. This study represents the first step of the creation of a robust modelling chain coupling the MS for the generation of HARH and disease forecasting models, including the systematic validation of each step of the simulation.

  1. [Impact of canopy structural characteristics on inner air temperature and relative humidity of Koelreuteria paniculata community in summer].

    PubMed

    Qin, Zhong; Li, Zhan-dong; Cheng, Fang-yun; Sha, Hai-feng

    2015-06-01

    To investigate the diurnal variation of the correlations between the cooling and humidifying effects and canopy structural characteristics of the Koelreuteria paniculata community, the measurements of air temperature, relative humidity, canopy density, leaf area index (LAI) and mean leaf angle (MLA) were performed on calm sunny summer days in the community in Beijing Olympic Forest Park, China. There were significant correlations between the canopy density, LAI and MLA, which affected the cooling and humidifying effects together. The cooling effect reached its maximum by 12:00, whereas the humidifying effect reached its peak at 10:00. Compared with the control open space site, the community appeared to lower the air temperature by 0.43 to 7.53 °C and to increase the relative humidity by 1%-22% during the daytime. However, the cooling and humidifying effects seem to be not effective during the night. The canopy density and LAI were better for determining the cooling and humidifying effects from 9:00 to 12:00. However, these effects were largely controlled only by the canopy density from 12:00 to 14:00 and were significantly correlated with the canopy density and LAI afterwards until 18:00. PMID:26572013

  2. Control of Relative Air Humidity as a Potential Means to Improve Hygiene on Surfaces: A Preliminary Approach with Listeria monocytogenes

    PubMed Central

    Zoz, Fiona; Iaconelli, Cyril; Lang, Emilie; Iddir, Hayet; Guyot, Stéphane; Grandvalet, Cosette; Gervais, Patrick; Beney, Laurent

    2016-01-01

    Relative air humidity fluctuations could potentially affect the development and persistence of pathogenic microorganisms in their environments. This study aimed to characterize the impact of relative air humidity (RH) variations on the survival of Listeria monocytogenes, a bacterium persisting on food processing plant surfaces. To assess conditions leading to the lowest survival rate, four strains of L. monocytogenes (EGDe, CCL500, CCL128, and LO28) were exposed to different RH conditions (75%, 68%, 43% and 11%) with different drying kinetics and then rehydrated either progressively or instantaneously. The main factors that affected the survival of L. monocytogenes were RH level and rehydration kinetics. Lowest survival rates between 1% and 0.001% were obtained after 3 hours of treatment under optimal conditions (68% RH and instantaneous rehydration). The survival rate was decreased under 0.001% after prolonged exposure (16h) of cells under optimal conditions. Application of two successive dehydration and rehydration cycles led to an additional decrease in survival rate. This preliminary study, performed in model conditions with L. monocytogenes, showed that controlled ambient RH fluctuations could offer new possibilities to control foodborne pathogens in food processing environments and improve food safety. PMID:26840373

  3. Humidity effects on photochemical aerosol formation in the SO 2-NO-C 3H 6-air system

    NASA Astrophysics Data System (ADS)

    Izumi, Katsuyuki; Mizuochi, Motoyuki; Murano, Kentaro; Fukuyama, Tsutomu

    In order to investigate the effects of humidity on the gas-phase oxidation of SO 2 in polluted air and on the subsequent aerosol formation process, photoirradiation experiments were carried out by means of a 4-m 3 chamber, in which mixtures containing SO 2, NO and C 3H 6 with concentrations in the ppm range were exposed to simulated solar radiation in different relative humidity (r.h.) conditions. The total amount of oxidized SO 2 was quantified from the SO 42- yield determined by the chemical analysis of the aerosol product, and a part due to the oxidation by the OH radical was evaluated by estimating the OH concentration from the decay rate of C 3H 6. The remaining part was assigned to the oxidation by the Criegee intermediate, as it had a good correlation with the progress of the O 3 + C 3H 6 reaction. The contributions of the two oxidizing species to the total conversion and the oxidation rate of SO 2 were measured as functions of r.h. As a result, experimental evidence was obtained for the prediction of Calvert and Stockwell's (1983, Envir. Sci. Technol. 17, 428A-443A) simulation that the oxidation due to the Criegee intermediate was retarded by the increase in humidity. The OH contribution, on the other hand, was almost independent of r.h. It was observed consequently that the total oxidized amount of SO 2 considerably decreased as r.h. was higher. The humidity effect on the aerosol formation process was found to be more complicated than the effect on the gas-phase chemistry. The maximum rate of increase in the particle number concentration rose linearly with increasing r.h., but the number concentration itself measured at its maximum or at the end of the irradiation reached a ceiling value around r.h. = 30% and went down for higher r.h. The average panicle size in the final stage of the reaction showed a minimum around the same r.h. at which the number concentration was maximum. The H 2SO 4 concentration in the mist particles, however, decreased

  4. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    NASA Technical Reports Server (NTRS)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    The goal of this research was to develop a dynamic model which can predict the effect of humidity swings on activated carbon adsorption beds used to remove trace contaminants from the atmosphere in spacecraft. Specifically, the model was to be incorporated into a computer simulation to predict contaminant concentrations exiting the bed as a function of time after a humidity swing occurs. Predicted breakthrough curves were to be compared to experimentally measured results. In all respects the research was successful. The two major aspects of this research were the mathematical model and the experiments. Experiments were conducted by Mr. Appel using a fixed-bed apparatus at NASA-Ames Research Center during the summers of 1994 and 1995 and during the first 8 months of 1996. Mr. Appel conducted most of his mathematical modeling work at the University of Virginia. The simulation code was used to predict breakthrough curves using adsorption equilibrium correlations developed previously by M. D. LeVan's research group at the University of Virginia. These predictions were compared with the experimental measurements, and this led to improvements in both the simulation code and the apparatus.

  5. Heating, Ventilation, and Air Conditioning Design Strategy for a Hot-Humid Production Builder

    SciTech Connect

    Kerrigan, P.

    2014-03-01

    BSC worked directly with the David Weekley Homes - Houston division to redesign three floor plans in order to locate the HVAC system in conditioned space. The purpose of this project is to develop a cost effective design for moving the HVAC system into conditioned space. In addition, BSC conducted energy analysis to calculate the most economical strategy for increasing the energy performance of future production houses. This is in preparation for the upcoming code changes in 2015. The builder wishes to develop an upgrade package that will allow for a seamless transition to the new code mandate. The following research questions were addressed by this research project: 1. What is the most cost effective, best performing and most easily replicable method of locating ducts inside conditioned space for a hot-humid production home builder that constructs one and two story single family detached residences? 2. What is a cost effective and practical method of achieving 50% source energy savings vs. the 2006 International Energy Conservation Code for a hot-humid production builder? 3. How accurate are the pre-construction whole house cost estimates compared to confirmed post construction actual cost? BSC and the builder developed a duct design strategy that employs a system of dropped ceilings and attic coffers for moving the ductwork from the vented attic to conditioned space. The furnace has been moved to either a mechanical closet in the conditioned living space or a coffered space in the attic.

  6. Wind Prediction Accuracy for Air Traffic Management Decision Support Tools

    NASA Technical Reports Server (NTRS)

    Cole, Rod; Green, Steve; Jardin, Matt; Schwartz, Barry; Benjamin, Stan

    2000-01-01

    The performance of Air Traffic Management and flight deck decision support tools depends in large part on the accuracy of the supporting 4D trajectory predictions. This is particularly relevant to conflict prediction and active advisories for the resolution of conflicts and the conformance with of traffic-flow management flow-rate constraints (e.g., arrival metering / required time of arrival). Flight test results have indicated that wind prediction errors may represent the largest source of trajectory prediction error. The tests also discovered relatively large errors (e.g., greater than 20 knots), existing in pockets of space and time critical to ATM DST performance (one or more sectors, greater than 20 minutes), are inadequately represented by the classic RMS aggregate prediction-accuracy studies of the past. To facilitate the identification and reduction of DST-critical wind-prediction errors, NASA has lead a collaborative research and development activity with MIT Lincoln Laboratories and the Forecast Systems Lab of the National Oceanographic and Atmospheric Administration (NOAA). This activity, begun in 1996, has focussed on the development of key metrics for ATM DST performance, assessment of wind-prediction skill for state of the art systems, and development/validation of system enhancements to improve skill. A 13 month study was conducted for the Denver Center airspace in 1997. Two complementary wind-prediction systems were analyzed and compared to the forecast performance of the then standard 60 km Rapid Update Cycle - version 1 (RUC-1). One system, developed by NOAA, was the prototype 40-km RUC-2 that became operational at NCEP in 1999. RUC-2 introduced a faster cycle (1 hr vs. 3 hr) and improved mesoscale physics. The second system, Augmented Winds (AW), is a prototype en route wind application developed by MITLL based on the Integrated Terminal Wind System (ITWS). AW is run at a local facility (Center) level, and updates RUC predictions based on an

  7. Vandenberg Air Force Base Upper Level Wind Launch Weather Constraints

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.; Wheeler, Mark M.

    2012-01-01

    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman III ballistic missile. The 30 OSSWF tasked the Applied Meteorology Unit (AMU) to analyze VAFB sounding data with the goal of determining the probability of violating (PoV) their upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a tool that will calculate the PoV of each constraint on the day of launch. In order to calculate the probability of exceeding each constraint, the AMU collected and analyzed historical data from VAFB. The historical sounding data were retrieved from the National Oceanic and Atmospheric Administration Earth System Research Laboratory archive for the years 1994-2011 and then stratified into four sub-seasons: January-March, April-June, July-September, and October-December. The maximum wind speed and 1000-ft shear values for each sounding in each subseason were determined. To accurately calculate the PoV, the AMU determined the theoretical distributions that best fit the maximum wind speed and maximum shear datasets. Ultimately it was discovered that the maximum wind speeds follow a Gaussian distribution while the maximum shear values follow a lognormal distribution. These results were applied when calculating the averages and standard deviations needed for the historical and real-time PoV calculations. In addition to the requirements outlined in the original task plan, the AMU also included forecast sounding data from the Rapid Refresh model. This information provides further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours on day of launch. The interactive graphical user interface (GUI) for this project was developed in

  8. Influence of Temperature, Relative Humidity, and Soil Properties on the Soil-Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models.

    PubMed

    Davie-Martin, Cleo L; Hageman, Kimberly J; Chin, Yu-Ping; Rougé, Valentin; Fujita, Yuki

    2015-09-01

    Soil-air partition coefficient (Ksoil-air) values are often employed to investigate the fate of organic contaminants in soils; however, these values have not been measured for many compounds of interest, including semivolatile current-use pesticides. Moreover, predictive equations for estimating Ksoil-air values for pesticides (other than the organochlorine pesticides) have not been robustly developed, due to a lack of measured data. In this work, a solid-phase fugacity meter was used to measure the Ksoil-air values of 22 semivolatile current- and historic-use pesticides and their degradation products. Ksoil-air values were determined for two soils (semiarid and volcanic) under a range of environmentally relevant temperature (10-30 °C) and relative humidity (30-100%) conditions, such that 943 Ksoil-air measurements were made. Measured values were used to derive a predictive equation for pesticide Ksoil-air values based on temperature, relative humidity, soil organic carbon content, and pesticide-specific octanol-air partition coefficients. Pesticide volatilization losses from soil, calculated with the newly derived Ksoil-air predictive equation and a previously described pesticide volatilization model, were compared to previous results and showed that the choice of Ksoil-air predictive equation mainly affected the more-volatile pesticides and that the way in which relative humidity was accounted for was the most critical difference. PMID:26258946

  9. 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 ...

  10. Interaction of multiple atmospheric-pressure micro-plasma jets in small arrays: He/O2 into humid air

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia Yu; Kushner, Mark J.

    2014-02-01

    Arrays of atmospheric-pressure plasma jets are being considered as a means to increase the area being treated in surface modification and in plasma medicine in particular. A unique challenge of scaling plasma jet arrays is that individual plasma jets in an array tend to interact with each other, which can lead to quenching of some individual jets. To investigate these potential interactions, a computational study of one-, two- and three-tube arrays of micro-plasma jet arrays was performed. An atmospheric-pressure He/O2 = 99.8/0.2 mixture was flowed through the tubes into humid room air. We found that the jets interact through electrostatic, hydrodynamic and photolytic means. The hydrodynamic interactions result from the merging of individual He channels emerging from individual tubes as air diffuses into the extended gas jets. Ionization waves (IWs) or plasma bullets, which form the jets on the boundaries of an array, encounter higher mole fractions of air earlier compared with the center jet and so are slower or are quenched earlier. The close proximity of the jets produces electrostatic repulsion, which affects the trajectories of the IWs. If the jets are close enough, photoionizing radiation from their neighbors is an additional form of interaction. These interactions are sensitive to the spacing of the jets.

  11. Combined effects of precipitation and air temperature on soil moisture in different land covers in a humid basin

    NASA Astrophysics Data System (ADS)

    Feng, Huihui; Liu, Yuanbo

    2015-12-01

    Soil moisture is a key variable in hydrological processes. Although the combined effects of multiple climatic factors in different land cover conditions are highly valuable for water resource management, a complete understanding of these effects remains unclear. This study used a cluster analysis approach to investigate the combined effects of precipitation and air temperature, rather than a single factor, in different land covers for an area over the Poyang Lake Basin in China from 2003 to 2009. Specifically, monthly soil moisture was classified into eight clusters according to the change in precipitation and air temperature; the clusters describe a range of climates from the extreme of wet-hot to that of dry-cold. For an individual climate factor, our results showed that the contribution of air temperature to soil moisture is greater than that of precipitation, and the effect of air temperature is more sensitive in different land covers. When considering the combined effects of precipitation and air temperature, soil moisture varies with land cover; however, the variation in a normal climate cluster is greater than in an extreme climate cluster. This indicated that land cover is the dominant factor in soil moisture variation in normal climatic conditions, whereas climate is the dominant factor in extreme conditions. As climate shifts from the wet-hot to the dry-cold cluster, soil moisture decreases for all land covers, with the minimum rate occurring in forest conditions. Meanwhile, soil moisture deficit and saturation are more likely to occur in grassland and forest areas, indicating that forest cover might mitigate drought. The results of this study provide an effective approach to investigate the combined effects of climate factors on soil moisture for various land covers in humid areas. This study also supports the management of water resources in changing climates.

  12. The Resistance of Spheres in Wind Tunnels and In Air

    NASA Technical Reports Server (NTRS)

    Bacon, D L; Reid, E G

    1924-01-01

    To supplement the standardization tests now in progress at several laboratories, a broad investigation of the resistance of spheres in wind tunnels and free air has been carried out by the National Advisory Committee for Aeronautics. The subject has been classed in aerodynamic research, and in consequence there is available a great mass of data from previous investigations. This material was given careful consideration in laying out the research, and explanation of practically all the disagreement between former experiments has resulted. A satisfactory confirmation of Reynolds law has been accomplished, the effect of means of support determined, the range of experiment greatly extended by work in the new variable density wind tunnel, and the effects of turbulence investigated by work in the tunnels and by towing and dropping tests in free air. It is concluded that the erratic nature of most of the previous work is due to support interference and differing turbulence conditions. While the question of support has been investigated thoroughly, a systematic and comprehensive study of the effects of scale and quality of turbulence will be necessary to complete the problem, as this phase was given only general treatment.

  13. High relative air humidity influences mineral accumulation and growth in iron deficient soybean plants

    PubMed Central

    Roriz, Mariana; Carvalho, Susana M. P.; Vasconcelos, Marta W.

    2014-01-01

    Iron (Fe) deficiency chlorosis (IDC) in soybean results in severe yield losses. Cultivar selection is the most commonly used strategy to avoid IDC but there is a clear interaction between genotype and the environment; therefore, the search for quick and reliable tools to control this nutrient deficiency is essential. Several studies showed that relative humidity (RH) may influence the long distance transport of mineral elements and the nutrient status of plants. Thus, we decided to analyze the response of an “Fe-efficient” (EF) and an “Fe-inefficient” (INF) soybean accession grown under Fe-sufficient and deficient conditions under low (60%) and high (90%) RH, evaluating morphological, and physiological parameters. Furthermore, the mineral content of different plant organs was analyzed. Our results showed beneficial effects of high RH in alleviating IDC symptoms as seen by increased SPAD values, higher plant dry weight (DW), increased plant height, root length, and leaf area. This positive effect of RH in reducing IDC symptoms was more pronounced in the EF accession. Also, Fe content in the different plant organs of the EF accession grown under deficient conditions increased with RH. The lower partitioning of Fe to roots and stems of the EF accessions relative to dry matter also supported our hypothesis, suggesting a greater capacity of this accession in Fe translocation to the aerial parts under Fe deficient conditions, when grown under high RH. PMID:25566297

  14. Evaluation of the response of tritium-in-air instrumentation to HT in dry and humid conditions and to HTO vapor

    SciTech Connect

    Phillips, H.; Dean, J.; Privas, E.

    2015-03-15

    Nuclear plant operators (power generation, decommissioning and reprocessing operations) are required to monitor releases of tritium species for regulatory compliance and radiation protection purposes. Tritium monitoring is performed using tritium-in-air gas monitoring instrumentation based either on flow-through ion chambers or proportional counting systems. Tritium-in-air monitors are typically calibrated in dry conditions but in service may operate at elevated levels of relative humidity. The NPL (National Physical Laboratory) radioactive gas-in-air calibration system has been used to study the effect of humidity on the response to tritium of two tritium-in-air ion chamber based monitors and one proportional counting system which uses a P10/air gas mixture. The response of these instruments to HTO vapour has also been evaluated. In each case, instrument responses were obtained for HT in dry conditions (relative humidity (RH) about 2%), HT in 45% RH, and finally HTO at 45% RH. Instrumentation response to HT in humid conditions has been found to slightly exceed that in dry conditions. (authors)

  15. Acoustic Humidity Sensor

    NASA Technical Reports Server (NTRS)

    Shakkottai, Parthasarathy; Kwack, Eug Y.; Venkateshan, Shakkottai

    1990-01-01

    Industrial humidity sensor measures volume fraction of water in air via its effect on speed of sound. Only portion of sensor exposed to sensed atmosphere is pair of stainless-steel tubes, one containing dry air and other containing moist air. Counters measure intervals between reflected pulses. Sensor rugged enough for use in harsh environments like those used to control drying of paper in paper mills, where most humidity sensors do not survive.

  16. Nocturnal drainage wind characteristics in two converging air sheds

    SciTech Connect

    Gedayloo, T.; Clements, W.E.; Barr, S.; Archuleta, J.A.

    1980-01-01

    During the short experimental period in the Grants Basin of Northeastern New Mexico a survey was conducted on the complex meteorology of this area. Emphasis was placed on the nocturnal drainage flow because of the potential hazards to the populated areas of Milan and Grants from the effluents of the uranium mining and milling operation in this area. This investigation has shown that the nocturnal drainage flow patterns agree with the winds predicted on the basis of the complex terrain of the area. Because of the surface cooling at night (over 25/sup 0/C during summer and about 20/sup 0/C during winter), air from elevated surrounding areas flows to the low lying regions consequently setting up a nocturnal drainage flow. This regime exists over 60% of the time during summer months and over 65% of the time during winter months with a depth generally less than 200 m. In the San Mateo air shed the drainage flow is east northeast, and in the Ambrosia Lake air shed it is from northwest. The confluence of these two air flows contributes mainly to the drainage flow through the channel formed by La Ja Mesa and Mesa Montanosa. The analysis of data collected by the recording Flats Station confirms the prediction that although the area south of the channel region broadens considerably causing a reduction in flow speed, contributions from the southside of La Jara Mesa and Mesa Montanosa partly compensate for this reduction. The position of this recording station is 15 to 20 km from the populated towns of Milan and Grants. A drainage flow speed of approximately 2.2 m s/sup -1/ and the duration of over 11 hours as recorded by this station indicates that air from the San Mateo and Ambrosia Lake regions may be transported southwards to these population centers during a nocturnal period. In order to test this prediction, a series of multi-atmospheric tracer experiments were conducted in the Grants Basin.

  17. Summary report on effects at temperature, humidity, and fuel-air ratio on two air-cooled light aircraft engines

    NASA Technical Reports Server (NTRS)

    Kempke, E. E., Jr.

    1976-01-01

    Five different engine models were tested to experimentally characterize emissions and to determine the effects of variation in fuel-air ratio and spark timing on emissions levels and other operating characteristics such as cooling, misfiring, roughness, power acceleration, etc. The results are given of two NASA reports covering the Avco Lycoming 0-320-D engine testing and the recently obtained results on the Teledyne Continental TSIO-360-C engine.

  18. Formation of reactive oxygen and nitrogen species by repetitive negatively pulsed helium atmospheric pressure plasma jets propagating into humid air

    NASA Astrophysics Data System (ADS)

    Norberg, Seth A.; Johnsen, Eric; Kushner, Mark J.

    2015-06-01

    Atmospheric pressure plasma jets have many beneficial effects in their use in surface treatment and, in particular, plasma medicine. One of these benefits is the controlled production of reactive oxygen and nitrogen species (RONS) in the active discharge through the molecular gases added to the primary noble gas in the input mixture, and through the interaction of reactive species in the plasma effluent with the ambient air. In this computational investigation, a parametric study was performed on the production of RONS in a multiply pulsed atmospheric pressure plasma jet sustained in a He/O2 mixture and flowing into ambient humid air. The consequences of flow rate, O2 fraction, voltage, and repetition rate on reactant densities after a single discharge pulse, after 30 pulses, and after the same total elapsed time were investigated. At the end of the first discharge pulse, voltage has the greatest influence on RONS production. However, the systematic trends for production of RONS depend on repetition rate and flow rate in large part due to the residence time of RONS in the plasma zone. Short residence times result in reactive species produced by the previous pulse still being in the discharge tube or in the path of the ionization wave at the next pulse. The RONS therefore accumulate in the tube and in the near effluent on a pulse-to-pulse basis. This accumulation enables species requiring multiple reactions among the primary RONS species to be produced in greater numbers.

  19. Performance analysis of a bio-gasification based combined cycle power plant employing indirectly heated humid air turbine

    NASA Astrophysics Data System (ADS)

    Mukherjee, S.; Mondal, P.; Ghosh, S.

    2016-07-01

    Rapid depletion of fossil fuel has forced mankind to look into alternative fuel resources. In this context, biomass based power generation employing gas turbine appears to be a popular choice. Bio-gasification based combined cycle provides a feasible solution as far as grid-independent power generation is concerned for rural electrification projects. Indirectly heated gas turbine cycles are promising alternatives as they avoid downstream gas cleaning systems. Advanced thermodynamic cycles have become an interesting area of study to improve plant efficiency. Water injected system is one of the most attractive options in this field of applications. This paper presents a theoretical model of a biomass gasification based combined cycle that employs an indirectly heated humid air turbine (HAT) in the topping cycle. Maximum overall electrical efficiency is found to be around 41%. Gas turbine specific air consumption by mass is minimum when pressure ratio is 6. The study reveals that, incorporation of the humidification process helps to improve the overall performance of the plant.

  20. Long-period humidity variability in the Arctic atmosphere from upper-air observations

    NASA Astrophysics Data System (ADS)

    Agurenko, A.; Khokhlova, A.

    2014-12-01

    Under climate change, atmospheric water content also tends to change. This gives rise to changes in the amount of moisture transferred, clouds and precipitation, as well as in hydrological regime. This work analyzes seasonal climatic characteristics of precipitated water in the Arctic atmosphere, by using 1972-2011 data from 55 upper-air stations located north of 60°N. Regions of maximum and minimum mean values and variability trends are determined. In the summer, water amount is shown to increase in nearly the whole of the latitudinal zone. The comparison with the similar characteristics of reanalysis obtained by the other authors shows a good agreement. Time variation in the atmosphere moisture transport crossing 70°N, which is calculated from observation data, is presented and compared with model results. The work is supported by the joint EC ERA.Net RUS and Russian Fundamental Research Fund Project "Arctic Climate Processes Linked Through the Circulation of the Atmosphere" (ACPCA) (project 12-05-91656-ЭРА_а).

  1. Temperature and Humidity Profiles in the "TqJoint" Data Group of AIRS Version 6 Product for the Climate Model Evaluation

    NASA Astrophysics Data System (ADS)

    Ding, F.; Fang, F.; Hearty, T. J., III; Theobald, M.; Vollmer, B.; Lynnes, C.

    2014-12-01

    The Atmospheric Infrared Sounder (AIRS) mission is entering its 13th year of global observations of the atmospheric state, including temperature and humidity profiles, outgoing longwave radiation, cloud properties, and trace gases. Thus AIRS data have been widely used, among other things, for short-term climate research and observational component for model evaluation. One instance is the fifth phase of the Coupled Model Intercomparison Project (CMIP5) which uses AIRS version 5 data (Tian et al. 2013) in the climate model evaluation. The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is the home of processing, archiving, and distribution services for data from the AIRS mission. The GES DISC, in collaboration with the AIRS Project, released data from the version 6 algorithm in early 2013. The new algorithm represents a significant improvement over previous versions in terms of greater stability, yield, and quality of products. The ongoing Earth System Grid for next generation climate model research project, a collaborative effort of GES DISC and NASA JPL, will bring temperature and humidity profiles from AIRS version 6. The AIRS version 6 product adds a new "TqJoint" data group, which contains data for a common set of observations across water vapor and temperature at all atmospheric levels and is suitable for climate process studies. How different may the monthly temperature and humidity profiles in "TqJoint" group be from the standard group where temperature and water vapor are not always valid at the same time? This study aims to answer the question by comprehensively comparing the temperature and humidity profiles from the TqJoint group and the standard group. The comparison includes absolute and relative differences, systematic trends at different levels, over land/sea and different latitude regions. We will also use MERRA data to examine the sampling differences between the "TqJoint" and standard group. The detail statistical

  2. Temperature and Humidity Profiles in the TqJoint Data Group of AIRS Version 6 Product for the Climate Model Evaluation

    NASA Technical Reports Server (NTRS)

    Ding, Feng; Fang, Fan; Hearty, Thomas J.; Theobald, Michael; Vollmer, Bruce; Lynnes, Christopher

    2014-01-01

    The Atmospheric Infrared Sounder (AIRS) mission is entering its 13th year of global observations of the atmospheric state, including temperature and humidity profiles, outgoing long-wave radiation, cloud properties, and trace gases. Thus AIRS data have been widely used, among other things, for short-term climate research and observational component for model evaluation. One instance is the fifth phase of the Coupled Model Intercomparison Project (CMIP5) which uses AIRS version 5 data in the climate model evaluation. The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is the home of processing, archiving, and distribution services for data from the AIRS mission. The GES DISC, in collaboration with the AIRS Project, released data from the version 6 algorithm in early 2013. The new algorithm represents a significant improvement over previous versions in terms of greater stability, yield, and quality of products. The ongoing Earth System Grid for next generation climate model research project, a collaborative effort of GES DISC and NASA JPL, will bring temperature and humidity profiles from AIRS version 6. The AIRS version 6 product adds a new "TqJoint" data group, which contains data for a common set of observations across water vapor and temperature at all atmospheric levels and is suitable for climate process studies. How different may the monthly temperature and humidity profiles in "TqJoint" group be from the "Standard" group where temperature and water vapor are not always valid at the same time? This study aims to answer the question by comprehensively comparing the temperature and humidity profiles from the "TqJoint" group and the "Standard" group. The comparison includes mean differences at different levels globally and over land and ocean. We are also working on examining the sampling differences between the "TqJoint" and "Standard" group using MERRA data.

  3. Restoration of an inner-city stream and its impact on air temperature and humidity based on long-term monitoring data

    NASA Astrophysics Data System (ADS)

    Kim, Kyu Rang; Kwon, Tae Heon; Kim, Yeon-Hee; Koo, Hae-Jung; Choi, Byoung-Cheol; Choi, Chee-Young

    2009-03-01

    Spatiotemporal changes in air temperature and humidity associated with the restoration of an innercity stream in Seoul, Korea, are investigated based on long-term monitoring data. The Cheonggye stream, covered under a concrete structure for 46 years, was restored in 2005 and runs 5.8 km eastward through a central region of Seoul. Long-term monitoring of the air temperature and relative humidity was made along the stream throughout the restoration and across the stream after the restoration. The area along the stream had a higher air temperature than the entire metropolitan area. The temperature anomaly between the monitoring area and the surrounding metropolitan area was 0.13°C lower on average at the center of the stream after the restoration. The stream’s effect on the air temperature was also evident in the temperature distribution along a street traversing the stream. The relative and specific humidities were increased due to the restoration. The restored stream modified the nearby urban climate in the opposite direction compared to urbanization. The results could be used as a model case in mitigating urban climate by a stream in future urban planning practices.

  4. Development and testing of a portable wind sensitive directional air sampler

    NASA Technical Reports Server (NTRS)

    Deyo, J.; Toma, J.; King, R. B.

    1975-01-01

    A portable wind sensitive directional air sampler was developed as part of an air pollution source identification system. The system is designed to identify sources of air pollution based on the directional collection of field air samples and their analysis for TSP and trace element characteristics. Sources can be identified by analyzing the data on the basis of pattern recognition concepts. The unit, designated Air Scout, receives wind direction signals from an associated wind vane. Air samples are collected on filter slides using a standard high volume air sampler drawing air through a porting arrangement which tracks the wind direction and permits collection of discrete samples. A preset timer controls the length of time each filter is in the sampling position. At the conclusion of the sampling period a new filter is automatically moved into sampling position displacing the previous filter to a storage compartment. Thus the Air Scout may be set up at a field location, loaded with up to 12 filter slides, and left to acquire air samples automatically, according to the wind, at any timer interval desired from 1 to 30 hours.

  5. A New Method for Deriving Ocean Surface Specific Humidity and Air Temperature: An Artificial Neural Network Approach.

    NASA Astrophysics Data System (ADS)

    Jones, Charles; Peterson, Pete; Gautier, Catherine

    1999-08-01

    A new methodology for deriving monthly averages of surface specific humidity (Qa) and air temperature (Ta) is described. Two main aspects characterize the new approach. First, remotely sensed parameters, total precipitable water (W), and sea surface temperature (SST) are used to derive Qa and Ta. Second, artificial neural networks (ANN) are employed to find transfer functions relating the input (W, SST) and output (Qa and Ta) parameters. Input data consist of nearly six years (January 1988-November 1993) of monthly averages of total precipitable water from Special Sensor Microwave/Imager data and sea surface temperature analysis from the National Centers for Environmental Prediction. Surface marine observations of Qa and Ta are used to develop and evaluate the new methodology.The performance of the algorithm is measured with surface marine observations not used in the development phase. Higher seasonally dependent discrepancies between Qa and Ta derived from the new method and in situ data are observed in regions such as the Kuroshio and Gulf Stream currents. After removal of systematic biases, the new method indicates that the combination of W and SST as input parameters and the ANN algorithm provides an interesting alternative for deriving monthly averaged surface parameters. The global mean bias in Qa is 0.010 ± 0.23 g kg1 over most oceanic areas, whereas root-mean-square (rms) differences are 0.77 ± 0.39 g kg1. Likewise, the global mean bias and rms in Ta are on the order of 7.3 × 105 ± 0.27°C and 0.72 ± 0.38°C, respectively.

  6. Compressed air energy storage system reservoir size for a wind energy baseload power plant

    SciTech Connect

    Cavallo, A.J.

    1996-12-31

    Wind generated electricity can be transformed from an intermittent to a baseload resource using an oversized wind farm in conjunction with a compressed air energy storage (CAES) system. The size of the storage reservoir for the CAES system (solution mined salt cavern or porous media) as a function of the wind speed autocorrelation time (C) has been examined using a Monte Carlo simulation for a wind class 4 (wind power density 450 W m{sup -2} at 50 m hub height) wind regime with a Weibull k factor of 2.5. For values of C typically found for winds over the US Great Plains, the storage reservoir must have a 60 to 80 hour capacity. Since underground reservoirs account for only a small fraction of total system cost, this larger storage reservoir has a negligible effect on the cost of energy from the wind energy baseload system. 7 refs., 2 figs., 1 tab.

  7. Measured Cooling Season Results Relating the Impact of Mechanical Ventilation on Energy, Comfort, and Indoor Air Quality in Humid Climates

    SciTech Connect

    Martin, Eric; Amos, Bryan; McIlvaine, Janet; Chasar, David; Widder, Sarah H.; Fonorow, Ken

    2014-08-22

    Conference Paper for ACEEE Summer Study in Buildings discussing results to date of a project evaluating the impact of ventialtion on energy use, comfort, durability, and cost in the hot humid climate.

  8. Nectar production of Epilobium angustifolium L. at different air humidities; nectar sugar in individual flowers and the optimal foraging theory.

    PubMed

    Bertsch, A

    1983-08-01

    The nectar production of Epilobium angustifolium L. was investigated at 20°C and 50%, 78% and 94% ambient humidity in the climatic test chamber. By means of permanent pipettes, freshly produced nectar was sucked off immediately after secretion, and nectar samples were also taken at 10-h and 48-h intervals to investigate the postsecretory influence of ambient humidity. Volume and sugar concentration of samples from individual flowers were measured and the sugar contained was calculated. The rate of sugar production remains constant for all ambient humidities and extraction intervals investigated; the mean value for all 180 samples is 1.55 mg sucrose equivalents/24h. Sugar concentration of secretion nectar is linearly dependent on ambient humidity over the range investigated, and nectar volume and sugar concentration change according to the theoretically expected curve for solutions with a sugar content of 1.55 mg sucrose. The response of secretion nectar to steplike changes in ambient humidity was investigated and the transient function described. The nectaries respond immediately to changes in ambient humidity. The consequences of the results for nectar production and nectar reward of individual flowers in the field and for the optimal foraging of pollinators are discussed. Discussion concentrates particularly on the following questions: what influence the variability of nectar reward in individual flowers may have on flower-visiting bumble-bees; whether these animals have the sensory capabilities to measure sugar exactly; and whether the water relations of pollinators may also influence foraging behaviour. PMID:25024144

  9. Internal gravity wave-atmospheric wind interaction - A cause of clear air turbulence.

    NASA Technical Reports Server (NTRS)

    Bekofske, K.; Liu, V. C.

    1972-01-01

    The interaction between an internal gravity wave (IGW) and a vertical wind shear is discussed as a possible cause in the production of clear air turbulence in the free atmosphere. It is shown that under certain typical condition the interaction of an IGW with a background wind shear near a critical level provides a mechanism for depositing sufficient momentum in certain regions of the atmosphere to significantly increase the local mean wind shear and to lead to the production of turbulence.

  10. Analysis of vector wind change with respect to time for Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Adelfang, S. I.

    1978-01-01

    A statistical analysis of the temporal variability of wind vectors at 1 km altitude intervals from 0 to 27 km altitude taken from a 10-year data sample of twice-daily rawinsode wind measurements over Vandenberg Air Force Base, California is presented.

  11. 10. INTERIOR VIEW OF WIND TUNNEL (1991). WrightPatterson Air ...

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

    10. INTERIOR VIEW OF WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  12. 11. INTERIOR VIEW OF WIND TUNNEL (1991). WrightPatterson Air ...

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

    11. INTERIOR VIEW OF WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  13. 9. INTERIOR VIEW OF WIND TUNNEL (1991). WrightPatterson Air ...

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

    9. INTERIOR VIEW OF WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  14. The Use of Red Green Blue (RGB) Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-Convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Zavodsky, Bradley; Molthan, Andrew; Jedlovec, Gary

    2013-01-01

    AIRS ozone and model PV analysis confirm the stratospheric air in RGB Air Mass imagery. Trajectories confirm winds south of the low were distinct from CCB driven winds. Cross sections connect the tropopause fold, downward motion, and high nearsurface winds. Comparison to conceptual models show Shapiro-Keyser features and sting jet characteristics were observed in a storm that impacted the U.S. East Coast. RGB Air Mass imagery can be used to identify stratospheric air and regions susceptible to tropopause folding and attendant non-convective winds.

  15. Method and apparatus for wind turbine air gap control

    DOEpatents

    Grant, James Jonathan; Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; DiMascio, Paul Stephen; Gadre, Aniruddha Dattatraya; Qu, Ronghai

    2007-02-20

    Methods and apparatus for assembling a wind turbine generator are provided. The wind turbine generator includes a core and a plurality of stator windings circumferentially spaced about a generator longitudinal axis, a rotor rotatable about the generator longitudinal axis wherein the rotor includes a plurality of magnetic elements coupled to a radially outer periphery of the rotor such that an airgap is defined between the stator windings and the magnetic elements and the plurality of magnetic elements including a radially inner periphery having a first diameter. The wind turbine generator also includes a bearing including a first member in rotatable engagement with a radially inner second member, the first member including a radially outer periphery, a diameter of the radially outer periphery of the first member being substantially equal to the first diameter, the rotor coupled to the stator through the bearing such that a substantially uniform airgap is maintained.

  16. Simulation of the Impact of New Air-Based Ocean Surface Wind Measurements on H*Wind Analyses

    NASA Technical Reports Server (NTRS)

    Miller, Timothy; Atlas, Robert; Black, Peter; Case, Jonathan; Chen, Shuyi; Hood, Robbie; Jones, Linwood; Ruff, Chris; Uhlhorn, Eric

    2008-01-01

    The H'Wind analysis, a product of the Hurricane Research Division of NOAA's Atlantic Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of wind speeds in a tropical cyclone. This product is designed to improve understanding of the extent and strength of the wind field, and to improve the assessment of hurricane intensity. See http://www.aoml.noaa.gov/hrd/data sub/wind.html. The Hurricane Imaging Radiometer (HIRad) is a new airborne microwave remote sensor for hurricane observations that is currently under development by NASA Marshall Space Flight Center, NOAA Hurricane Research Division, the University of Central Florida and the University of Michigan. HIRad is being designed to enhance the real-time airborne ocean surface winds observation capabilities of NOAA and USAF Weather Squadron hurricane hunter aircraft using the operational airborne Stepped Frequency Microwave Radiometer (SFMR). Unlike SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRad will provide images of the surface wind and rain field over a wide swath (approx. 3 x the aircraft altitude). The instrument is described in a paper presented to the Hurricanes and Tropical Meteorology Symposium. The present paper describes a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing instruments (air, surface, and space-based) are simulated from the output of a numerical model from the University of Miami and those results are used to construct H*Wind analyses. Evaluations will be presented on the impact of the HIRad instrument on H'Wind analyses, both in terms of adding it to the full suite of current measurements, as well as using it to replace instrument(s) that may not be functioning at the future tame the HIRad instrument is implemented.

  17. NARSTO PAC2001 GVRD CAPMON AIR QUAL DATA

    Atmospheric Science Data Center

    2014-04-25

    ... Temperature Probe Humidity Probe Wind Sensor UV Ozone Detector Chemiluminescence TEOM GC-MS Ion Chromatograph ... Related Data:  Spatial Coverage: Canada Pacific 2001 Air Quality Study SCAR-B Block:  ...

  18. Automation&Characterization of US Air Force Bench Top Wind Tunnels - Summary Report

    SciTech Connect

    Hardy, J.E.

    2006-03-23

    The United States Air Force Precision Measurement Equipment Laboratories (PMEL) calibrate over 1,000 anemometer probes per year. To facilitate a more efficient calibration process for probe-style anemometers, the Air Force Metrology and Calibration Program underwent an effort to modernize the existing PMEL bench top wind tunnels. Through a joint effort with the Department of Energy's Oak Ridge National Laboratory, the performance of PMEL wind tunnels was improved. The improvement consisted of new high accuracy sensors, automatic data acquisition, and a software-driven calibration process. As part of the wind tunnel upgrades, an uncertainty analysis was completed, laser Doppler velocimeter profiling was conducted to characterize the velocities at probe locations in the wind tunnel, and pitot tube calibrations of the wind tunnel were verified. The bench top wind tunnel accuracy and repeatability has been measured for nine prototype wind tunnel systems and valuable field experience has been gained with these wind tunnels at the PMELs. This report describes the requirements for the wind tunnel improvements along with actual implementation strategies and details. Lessons-learned from the automation, the velocity profiling, and the software-driven calibration process will also be discussed.

  19. Simulation of air-droplet mixed phase flow in icing wind-tunnel

    NASA Astrophysics Data System (ADS)

    Mengyao, Leng; Shinan, Chang; Menglong, Wu; Yunhang, Li

    2013-07-01

    Icing wind-tunnel is the main ground facility for the research of aircraft icing, which is different from normal wind-tunnel for its refrigeration system and spraying system. In stable section of icing wind-tunnel, the original parameters of droplets and air are different, for example, to keep the nozzles from freezing, the droplets are heated while the temperature of air is low. It means that complex mass and heat transfer as well as dynamic interactive force would happen between droplets and air, and the parameters of droplet will acutely change along the passageway. Therefore, the prediction of droplet-air mixed phase flow is necessary in the evaluation of icing researching wind-tunnel. In this paper, a simplified droplet-air mixed phase flow model based on Lagrangian method was built. The variation of temperature, diameter and velocity of droplet, as well as the air flow field, during the flow process were obtained under different condition. With calculating three-dimensional air flow field by FLUENT, the droplet could be traced and the droplet distribution could also be achieved. Furthermore, the patterns about how initial parameters affect the parameters in test section were achieved. The numerical simulation solving the flow and heat and mass transfer characteristics in the mixing process is valuable for the optimization of experimental parameters design and equipment adjustment.

  20. Application of Artificial Neural Networks to the Development of Improved Multi-Sensor Retrievals of Near-Surface Air Temperature and Humidity Over Ocean

    NASA Technical Reports Server (NTRS)

    Roberts, J. Brent; Robertson, Franklin R.; Clayson, Carol Anne

    2012-01-01

    Improved estimates of near-surface air temperature and air humidity are critical to the development of more accurate turbulent surface heat fluxes over the ocean. Recent progress in retrieving these parameters has been made through the application of artificial neural networks (ANN) and the use of multi-sensor passive microwave observations. Details are provided on the development of an improved retrieval algorithm that applies the nonlinear statistical ANN methodology to a set of observations from the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit (AMSU-A) that are currently available from the NASA AQUA satellite platform. Statistical inversion techniques require an adequate training dataset to properly capture embedded physical relationships. The development of multiple training datasets containing only in-situ observations, only synthetic observations produced using the Community Radiative Transfer Model (CRTM), or a mixture of each is discussed. An intercomparison of results using each training dataset is provided to highlight the relative advantages and disadvantages of each methodology. Particular emphasis will be placed on the development of retrievals in cloudy versus clear-sky conditions. Near-surface air temperature and humidity retrievals using the multi-sensor ANN algorithms are compared to previous linear and non-linear retrieval schemes.

  1. Differences between water permeability of astomatous and stomatous cuticular membranes: effects of air humidity in two species of contrasting drought-resistance strategy

    PubMed Central

    Karbulková, Jana; Schreiber, Lukas; Macek, Petr; Šantrůček, Jiří

    2008-01-01

    Cuticular water permeabilities of adaxial and abaxial leaf surfaces and their dependence on relative air humidity (RH) applied in long-term and short-term regimes have been analysed for Hedera helix, native in a temperate climate, and Zamioculcas zamiifolia, native in subtropical regions. The water permeability of cuticular membranes (CM) isolated from the adaxial (astomatous) and abaxial (stomatous) leaf sides was measured using a method which allowed the separation of water diffusion through the remnants of the original stomatal pores from water diffusion through the solid cuticle. The long-term effects of low (20–40%) or high (60–80%) RH applied during plant growth and leaf ontogeny (‘growth RH’) and the short-term effects of applying 2% or 100% RH while measuring permeability (‘measurement RH’) were investigated. With both species, water permeability of the solid stomatous CM was significantly higher than the permeability of the astomatous CM. Adaxial cuticles of plants grown in humid air were more permeable to water than those from dry air. The adaxial CM of the drought-tolerant H. helix was more permeable and more sensitive to growth RH than the adaxial CM of Z. zamiifolia, a species avoiding water stress. However, permeability of the solid abaxial CM was similar in both species and independent of growth RH. The lack of a humidity response in the abaxial CM is attributed to a higher degree of cuticular hydration resulting from stomatal transpiration. The ecophysiological significance of higher permeability of the solid stomatous CM compared to the astomatous CM is discussed. PMID:18836141

  2. Interpretation of combined wind profiler and aircraft-measured tropospheric winds and clear air turbulence

    NASA Technical Reports Server (NTRS)

    Thomson, D. W.; Syrett, William J.; Fairall, C. W.

    1991-01-01

    In the first experiment, it was found that wind profilers are far better suited for the detailed examination of jet stream structure than are weather balloons. The combination of good vertical resolution with not previously obtained temporal resolution reveals structural details not seen before. Development of probability-derived shear values appears possible. A good correlation between pilot reports of turbulence and wind shear was found. In the second experiment, hourly measurements of wind speed and direction obtained using two wind profiling Doppler radars during two prolonged jet stream occurrences over western Pennsylvania were analyzed. In particular, the time-variant characteristics of derived shear profiles were examined. Profiler data dropouts were studied in an attempt to determine possible reasons for the apparently reduced performance of profiling radar operating beneath a jet stream. Richardson number and wind shear statistics were examined along with pilot reports of turbulence in the vicinity of the profiler.

  3. Humidity coefficient correction in the calculation equations of air refractive index by He-Ne laser based on phase step interferometry.

    PubMed

    Chen, Qianghua; Liu, Jinghai; He, Yongxi; Luo, Huifu; Luo, Jun; Wang, Feng

    2015-02-10

    The refractive index of air (RIA) is an important parameter in precision measurement. The revisions to Edlen's equations by Boensch and Potulski [Metrologia 35, 133 (1998)] are mostly used to calculate the RIA at present. Since the humidity correction coefficients in the formulas were performed with four wavelengths of a Cd(114) lamp (644.0, 508.7, 480.1, and 467.9 nm) and at the temperature range of 19.6°C-20.1°C, the application is restricted when an He-Ne laser is used as the light source, which is mostly applied in optical precision measurement, and the environmental temperature is far away from 20°C as well. To solve this problem, a measurement system based on phase step interferometry for measuring the effect of the humidity to the RIA is presented, and a corresponding humidity correction equation is derived. The analysis and comparison results show that the uncertainty of the presented equation is better than that of Boensch and Potulski's. It is more suitable in present precision measurements by He-Ne laser, and the application temperature range extends to 14.6°C-24.0°C as well. PMID:25968028

  4. Response surface modeling for hot, humid air decontamination of materials contaminated with Bacillus anthracis ∆Sterne and Bacillus thuringiensis Al Hakam spores

    PubMed Central

    2014-01-01

    Response surface methodology using a face-centered cube design was used to describe and predict spore inactivation of Bacillus anthracis ∆Sterne and Bacillus thuringiensis Al Hakam spores after exposure of six spore-contaminated materials to hot, humid air. For each strain/material pair, an attempt was made to fit a first or second order model. All three independent predictor variables (temperature, relative humidity, and time) were significant in the models except that time was not significant for B. thuringiensis Al Hakam on nylon. Modeling was unsuccessful for wiring insulation and wet spores because there was complete spore inactivation in the majority of the experimental space. In cases where a predictive equation could be fit, response surface plots with time set to four days were generated. The survival of highly purified Bacillus spores can be predicted for most materials tested when given the settings for temperature, relative humidity, and time. These predictions were cross-checked with spore inactivation measurements. PMID:24949256

  5. Air emissions due to wind and solar power.

    PubMed

    Katzenstein, Warren; Apt, Jay

    2009-01-15

    Renewables portfolio standards (RPS) encourage large-scale deployment of wind and solar electric power. Their power output varies rapidly, even when several sites are added together. In many locations, natural gas generators are the lowest cost resource available to compensate for this variability, and must ramp up and down quickly to keep the grid stable, affecting their emissions of NOx and CO2. We model a wind or solar photovoltaic plus gas system using measured 1-min time-resolved emissions and heat rate data from two types of natural gas generators, and power data from four wind plants and one solar plant. Over a wide range of renewable penetration, we find CO2 emissions achieve approximately 80% of the emissions reductions expected if the power fluctuations caused no additional emissions. Using steam injection, gas generators achieve only 30-50% of expected NOx emissions reductions, and with dry control NOx emissions increase substantially. We quantify the interaction between state RPSs and NOx constraints, finding that states with substantial RPSs could see significant upward pressure on NOx permit prices, if the gas turbines we modeled are representative of the plants used to mitigate wind and solar power variability. PMID:19238948

  6. Mars Science Laboratory relative humidity observations: Initial results

    PubMed Central

    Harri, A-M; Genzer, M; Kemppinen, O; Gomez-Elvira, J; Haberle, R; Polkko, J; Savijärvi, H; Rennó, N; Rodriguez-Manfredi, JA; Schmidt, W; Richardson, M; Siili, T; Paton, M; Torre-Juarez, M De La; Mäkinen, T; Newman, C; Rafkin, S; Mischna, M; Merikallio, S; Haukka, H; Martin-Torres, J; Komu, M; Zorzano, M-P; Peinado, V; Vazquez, L; Urqui, R

    2014-01-01

    The Mars Science Laboratory (MSL) made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity (REMS-H), and UV measurements. We concentrate on describing the REMS-H measurement performance and initial observations during the first 100 MSL sols as well as constraining the REMS-H results by comparing them with earlier observations and modeling results. The REMS-H device is based on polymeric capacitive humidity sensors developed by Vaisala Inc., and it makes use of transducer electronics section placed in the vicinity of the three humidity sensor heads. The humidity device is mounted on the REMS boom providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The final relative humidity results appear to be convincing and are aligned with earlier indirect observations of the total atmospheric precipitable water content. The water mixing ratio in the atmospheric surface layer appears to vary between 30 and 75 ppm. When assuming uniform mixing, the precipitable water content of the atmosphere is ranging from a few to six precipitable micrometers. Key Points Atmospheric water mixing ratio at Gale crater varies from 30 to 140 ppm MSL relative humidity observation provides good data Highest detected relative humidity reading during first MSL 100 sols is RH75% PMID:26213667

  7. Pattern recognition methods and air pollution source identification. [based on wind direction

    NASA Technical Reports Server (NTRS)

    Leibecki, H. F.; King, R. B.

    1978-01-01

    Directional air samplers, used for resolving suspended particulate matter on the basis of time and wind direction were used to assess the feasibility of characterizing and identifying emission source types in urban multisource environments. Filters were evaluated for 16 elements and X-ray fluorescence methods yielded elemental concentrations for direction, day, and the interaction of direction and day. Large numbers of samples are necessary to compensate for large day-to-day variations caused by wind perturbations and/or source changes.

  8. A Peak Wind Probability Forecast Tool for Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Crawford, Winifred; Roeder, William

    2008-01-01

    This conference abstract describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida. The peak winds are an important forecast element for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a short-range peak-wind forecast tool to assist in forecasting LCC violatioas.The tool will include climatologies of the 5-minute mean end peak winds by month, hour, and direction, and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  9. Indoor air quality in two urban elementary schools--measurements of airborne fungi, carpet allergens, CO2, temperature, and relative humidity.

    PubMed

    Ramachandran, Gurumurthy; Adgate, John L; Banerjee, Sudipto; Church, Timothy R; Jones, David; Fredrickson, Ann; Sexton, Ken

    2005-11-01

    This article presents measurements of biological contaminants in two elementary schools that serve inner city minority populations. One of the schools is an older building; the other is newer and was designed to minimize indoor air quality problems. Measurements were obtained for airborne fungi, carpet loadings of dust mite allergens, cockroach allergens, cat allergens, and carpet fungi. Carbon dioxide concentrations, temperature, and relative humidity were also measured. Each of these measurements was made in five classrooms in each school over three seasons--fall, winter, and spring. We compared the indoor environments at the two schools and examined the variability in measured parameters between and within schools and across seasons. A fixed-effects, nested analysis was performed to determine the effect of school, season, and room-within-school, as well as CO2, temperature and relative humidity. The levels of all measured parameters were comparable for the two schools. Carpet culturable fungal concentrations and cat allergen levels in the newer school started and remained higher than in the older school over the study period. Cockroach allergen levels in some areas were very high in the newer school and declined over the study period to levels lower than the older school. Dust mite allergen and culturable fungal concentrations in both schools were relatively low compared with benchmark values. The daily averages for temperature and relative humidity frequently did not meet ASHRAE guidelines in either school, which suggests that proper HVAC and general building operation and maintenance procedures are at least as important as proper design and construction for adequate indoor air quality. The results show that for fungi and cat allergens, the school environment can be an important exposure source for children. PMID:16223714

  10. 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

  11. Understanding run-in behavior of diamond-like carbon friction and preventing diamond-like carbon wear in humid air.

    PubMed

    Marino, Matthew J; Hsiao, Erik; Chen, Yongsheng; Eryilmaz, Osman L; Erdemir, Ali; Kim, Seong H

    2011-10-18

    The friction behavior of diamond-like carbon (DLC) is very sensitive to the test environment. For hydrogen-rich DLC tested in dry argon and hydrogen, there was always an induction period, so-called "run-in" period, during which the friction coefficient was high and gradually decreased before DLC showed an ultralow friction coefficient (less than 0.01) behavior. Regardless of friction coefficients and hydrogen contents, small amounts of wear were observed in dry argon, hydrogen, oxygen, and humid argon environments. Surprisingly, there were no wear or rubbing scar on DLC surfaces tested in n-pentanol vapor conditions, although the friction coefficient was relatively high among the five test environments. Ex situ X-ray photoelectron and near-edge X-ray absorption fine-structure spectroscopy analyses failed to reveal any differences in chemical composition attributable to the environment dependence of DLC friction and wear. The failure of getting chemical information of oxygenated surface species from the ex situ analysis was found to be due to facile oxidation of the DLC surface upon exposure to air. The removal or wear of this surface oxide layer is responsible for the run-in behavior of DLC. It was discovered that the alcohol vapor can also prevent the oxidized DLC surface from wear in humid air conditions. PMID:21888344

  12. Effect of High Temperature Storage in Vacuum, Air, and Humid Conditions on Degradation of Gold/Aluminum Wire Bonds in PEMs

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2006-01-01

    Microcircuits encapsulated in three plastic package styles were stored in different environments at temperatures varying from 130 C to 225 C for up to 4,000 hours in some cases. To assess the effect of oxygen, the parts were aged at high temperatures in air and in vacuum chambers. The effect of humidity was evaluated during long-term highly accelerated temperature and humidity stress testing (HAST) at temperatures of 130 C and 150 C. High temperature storage testing of decapsulated microcircuits in air, vacuum, and HAST chambers was carried out to evaluate the role of molding compounds in the environmentally-induced degradation and failure of wire bonds (WB). This paper reports on accelerating factors of environment and molding compound on WB failures. It has been shown that all environments, including oxygen, moisture, and the presence of molding compounds reduce time-to-failures compared to unencapsulated devices in vacuum conditions. The mechanism of the environmental effect on KB degradation is discussed.

  13. Influences of wind on the uptake of XAD passive air sampler in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Wang, Xiaoping; Liu, Xiande

    2016-04-01

    The passive air sampler based on XAD-2 resin (XAD-PAS) is a useful tool for studying the long-range atmospheric transport of persistent organic pollutants (POPs) in the remote or high-altitude regions. Due to its opening bottom, the sampling processes of XAD-PAS was influenced by wind or air turbulence. By now, there were no studies focusing on the wind impact on the sampling rates (R values) in field. In this study, three sampling sites in the Tibetan Plateau, a high-altitude region with large range of wind speed (v), were chosen to calibrate XAD-PAS. In the low-wind regions, the R values fitted for the predicted values by ambient tempratrue (T) and air pressure (P). In the windy regions, not only T and P but also v impacted the R values, and an equation for estimating the R values was developed in the windy regions. Air turbulence may introduce the uncertainties of the R values, therefore, the improved type with spoilers on the bottom of XAD-PAS were designed to decrease the uncertainties. The observed R values of the improved XAD-PAS in field were good agreement with the predicted R values only by T^1.75/P, indicating that the improved XAD-PAS can decrease the influence of wind.

  14. Air/ground wind shear information integration: Flight test results

    NASA Technical Reports Server (NTRS)

    Hinton, David A.

    1992-01-01

    An element of the NASA/FAA wind shear program is the integration of ground-based microburst information on the flight deck, to support airborne wind shear alerting and microburst avoidance. NASA conducted a wind shear flight test program in the summer of 1991 during which airborne processing of Terminal Doppler Weather Radar (TDWR) data was used to derive microburst alerts. High level microburst products were extracted from TDWR, transmitted to a NASA Boeing 737 in flight via data link, and processed to estimate the wind shear hazard level (F-factor) that would be experienced by the aircraft in the core of each microburst. The microburst location and F-factor were used to derive a situation display and alerts. The situation display was successfully used to maneuver the aircraft for microburst penetrations, during which in situ 'truth' measurements were made. A total of 19 penetrations were made of TDWR-reported microburst locations, resulting in 18 airborne microburst alerts from the TDWR data and two microburst alerts from the airborne in situ measurements. The primary factors affecting alerting performance were spatial offset of the flight path from the region of strongest shear, differences in TDWR measurement altitude and airplane penetration altitude, and variations in microburst outflow profiles. Predicted and measured F-factors agreed well in penetrations near microburst cores. Although improvements in airborne and ground processing of the TDWR measurement would be required to support an airborne executive-level alerting protocol, the feasibility of airborne utilization of TDWR data link data has been demonstrated.

  15. Laminar Flow Supersonic Wind Tunnel primary air injector

    NASA Technical Reports Server (NTRS)

    Smith, Brooke Edward

    1993-01-01

    This paper describes the requirements, design, and prototype testing of the flex-section and hinge seals for the Laminar Flow Supersonic Wind Tunnel Primary Injector. The supersonic atmospheric primary injector operates between Mach 1.8 and Mach 2.2 with mass-flow rates of 62 to 128 lbm/s providing the necessary pressure reduction to operate the tunnel in the desired Reynolds number (Re) range.

  16. Air Density And Wind Retrieval Using GOCE Data

    NASA Astrophysics Data System (ADS)

    Doornbos, E.; Bruinsma, S.; Fritsche, B.; Visser, P.; Van Den IJssel, J.; Encarnacao, J. Teixeira; Kern, M.

    2013-12-01

    In the GOCE+ Theme 3 project, ion thruster activation data from GOCE telemetry has been combined with the accelerometer and star camera data products, to derive a new set of data products on thermosphere neutral density and wind speed. These products can be seen as an ex- tension of the successful accelerometer-derived thermosphere density data sets from CHAMP and GRACE. It is the first time that such data, spanning multiple years, is available at a fixed and very low altitude and at a near constant orientation of the orbit plane with respect to the Sun. The data processing is based on an analysis of the aerodynamic accelerations acting on the satellite, and makes use of data from all instruments onboard the satellite. The following steps are involved: 1) estimation of the bias in the gradiometer common-mode accelerations using GPS tracking data, 2) conversion of ion thruster activation data to accelerations, 3) modelling of radiation pressure accelerations based on orbit and attitude information, 4) removal of radiation pressure and ion thruster accelerations from the common-mode acceleration data, to arrive at the observed aerodynamic accelerations, 5) iterative adjustment of wind direction and density inputs of an aerodynamic model of the satellite, until the modelled aerodynamic accelerations match the observations. The resulting density and wind observations are made available in the form of time series and grids. These data can be applied in investigations of solar-terrestrial physics, as well as for the improvement and validation of models used in space operations.

  17. Forecasting Cool Season Daily Peak Winds at Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Barrett, Joe, III; Short, David; Roeder, William

    2008-01-01

    The expected peak wind speed for the day is an important element in the daily 24-Hour and Weekly Planning Forecasts issued by the 45th Weather Squadron (45 WS) for planning operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The morning outlook for peak speeds also begins the warning decision process for gusts ^ 35 kt, ^ 50 kt, and ^ 60 kt from the surface to 300 ft. The 45 WS forecasters have indicated that peak wind speeds are a challenging parameter to forecast during the cool season (October-April). The 45 WS requested that the Applied Meteorology Unit (AMU) develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. The tool must only use data available by 1200 UTC to support the issue time of the Planning Forecasts. Based on observations from the KSC/CCAFS wind tower network, surface observations from the Shuttle Landing Facility (SLF), and CCAFS upper-air soundings from the cool season months of October 2002 to February 2007, the AMU created multiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence, the temperature inversion depth, strength, and wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft. Six synoptic patterns were identified: 1) surface high near or over FL, 2) surface high north or east of FL, 3) surface high south or west of FL, 4) surface front approaching FL, 5) surface front across central FL, and 6) surface front across south FL. The following six predictors were selected: 1) inversion depth, 2) inversion strength, 3) wind gust factor, 4) synoptic weather pattern, 5) occurrence of

  18. VAB Temperature and Humidity Study

    NASA Technical Reports Server (NTRS)

    Lane, John E.; Youngquist, Robert C.; Muktarian, Edward; Nurge, Mark A.

    2014-01-01

    In 2012, 17 data loggers were placed in the VAB to measure temperature and humidity at 10-minute intervals over a one-year period. In 2013, the data loggers were replaced with an upgraded model and slight adjustments to their locations were made to reduce direct solar heating effects. The data acquired by the data loggers was compared to temperature data provided by three wind towers located around the building. It was found that the VAB acts as a large thermal filter, delaying and reducing the thermal oscillations occurring outside of the building. This filtering is typically more pronounced at higher locations in the building, probably because these locations have less thermal connection with the outside. We surmise that the lower elevations respond more to outside temperature variations because of air flow through the doors. Temperatures inside the VAB rarely exceed outdoor temperatures, only doing so when measurements are made directly on a surface with connection to the outside (such as a door or wall) or when solar radiation falls directly on the sensor. A thermal model is presented to yield approximate filter response times for various locations in the building. Appendix A contains historical thermal and humidity data from 1994 to 2009.

  19. A large volume 2000 MPA air source for the radiatively driven hypersonic wind tunnel

    SciTech Connect

    Constantino, M

    1999-07-14

    An ultra-high pressure air source for a hypersonic wind tunnel for fluid dynamics and combustion physics and chemistry research and development must provide a 10 kg/s pure air flow for more than 1 s at a specific enthalpy of more than 3000 kJ/kg. The nominal operating pressure and temperature condition for the air source is 2000 MPa and 900 K. A radial array of variable radial support intensifiers connected to an axial manifold provides an arbitrarily large total high pressure volume. This configuration also provides solutions to cross bore stress concentrations and the decrease in material strength with temperature. [hypersonic, high pressure, air, wind tunnel, ground testing

  20. Report Card on Humidity Control.

    ERIC Educational Resources Information Center

    Fischer, John C.; Bayer, Charlene

    2003-01-01

    Reports on an investigation of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62-1999 on outdoor ventilation rates and space humidity levels for schools. Examined conventional cooling versus desiccant-based systems designed to control indoor humidity levels. Discusses the effectiveness of systems…

  1. Validation of the Atmospheric Infrared Sounder (AIRS) over the Antarctic Plateau: Low Radiance, Low Humidity, and Thin Clouds

    NASA Technical Reports Server (NTRS)

    Tobin, David C.

    2005-01-01

    The main goal of the project has been to use specialized measurements collected at the Antarctic Plateau to provide validation of the Atmospheric InfraRed Sounder (AIRS) spectral radiances and some AIRS Level 2 products. As proposed, efforts conducted at the University of Wisconsin are focused on providing technical information, data, and software in support of the validation studies.

  2. Measuring Vertical Profiles of Wind, Temperature and Humidity within the Atmospheric Boundary Layer using the Research UAVs 'M2AV Carolo'

    NASA Astrophysics Data System (ADS)

    Bange, J.; Martin, S.

    2009-09-01

    The measurement of vertical profiles is important to characterise the vertical structure of the atmospheric boundary layer (ABL). For instance, the dependence of the potential temperature on altitude defines the thermal stratification. The mechanical shear (i.e. the variation of wind speed and direction) produces turbulence and turbulent fluxes. The top of the ABL is required for scaling approaches (e.g. Deardorff scaling in the convective boundary layer, local scaling in the stable boundary layer). The Meteorological Mini Aerial Vehicles (M²AV) are self-constructed, automatically operating research aircraft of 6 kg in weight (including 1.5 kg scientific payload) and 2 m wingspan. These systems are capable of performing turbulence measurements (wind vector, temperature and humidity) and are used as a new instrument for measuring vertical profiles of the lower troposphere. Compared to a radiosonde, the spatial resolution of the M²AV is significantly higher. Especially the wind measurement is significantly more accurate compared to radiosonde data when using an aircraft that is equipped with a proper flow sensor (mainly a five-hole probe). It is important to maintain flow angles (sideslip and angle of attack) within the calibration range (typically 10 to 20 degree). This limits the vertical speed (the rate of climb and descent) of the research aircraft. In general there are two approaches to measure vertical profiles with research aircraft. Instantaneous profiles (slant flight pattern) are suitable if only little time is available, if the ABL is very in-stationary (or the aircraft is slow), if the dependence of the profile on time is requested (repeated slant flight patterns over one location) or if the dependence of the profile on the location is requested (saw-tooth pattern). For mean profiles (horizontal straight and level flights 'legs' at several altitudes within the ABL) it is necessary to use fast sensors. If the response time is too large, the vertical

  3. Monitoring of cave air temperature and humidity in the Niedźwiedzia Cave system (Sudetes, Poland) - a key to understanding tourists activity impact to cave environment

    NASA Astrophysics Data System (ADS)

    Gasiorowski, M.; Hercman, H.

    2012-04-01

    The Niedźwiedzia Cave is located in Śnieżnik Massif (the Easter Sudetes, SW Poland) at 800 m a.s.l. The length of known passages is ~3000 m and denivelation is 69 m. The system is composed of 3 levels of passages and chambers. It is a show cave with ~80,000 visitors every year. In 2010 we started monitoring program of cave air temperature and humidity, drip rate, stable isotopes and Uranium and Polonium content in water in selected sites inside the cave and in its vicinity. Changes in dropping rate in upper level are well correlated with precipitation. However, a response of dripping to rainfall depends on former precipitation frequency and intensity - during the humid period the dripping reacts immediately and after long dry period dripping responses with two-weeks delay. There is not so direct correlation between precipitation and dripping in lower level of the system. Air temperature inside the cave is almost stable in lower level (mean annual ~5.3 °C, and annual variation up to 0.7 °C) and more dynamic in the middle level (mean annual ~6.4 °C, and mean annual amplitude up to 4 °C). Daily and weekly measured changes of cave air temperature demonstrate extremely well correlation with number of visitors. In show cave passages (the middle level of the system) temperature increase 0.1-0.2 °C during every day when the cave is open for tourists and such changes is not observed during days without visitors and in lower level of the system closed for tourists. But even short visits of 3-4 cavers are recorded by temperature sensors exposed in the lower level (~0.02 °C increase). It proves very high sensitivity of cave environment to human activity. This study is funded by the National Science Centre and Higher Education grant no. N N306 131038.

  4. Mars Science Laboratory (MSL) - First Results of Relative Humidity Observations

    NASA Astrophysics Data System (ADS)

    Genzer, Maria; Harri, Ari-Matti; Kemppinen, Osku; Gómez-Elvira, Javier; Renno, Nilton; Savijärvi, Hannu; Schmidt, Walter; Polkko, Jouni; Rodríquez-Manfredi, Jose Antonio; de la Torre Juárez, Manuel; Mischna, Michael; Martín-Torres, Javier; Haukka, Harri; Paz Zorzano-Mier, Maria; Rafkin, Scott; Paton, Mark; MSL Science Team

    2013-04-01

    The Mars Science laboratory (MSL) called Curiosity made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity, and UV measurements. The REMS instrument suite is described at length in [1]. We concentrate on describing the first results from the REMS relative humidity observations and comparison of the measurements with modeling results. The REMS humidity device is provided by the Finnish Meteorological Institute. It is based on polymeric capacitive humidity sensors developed by Vaisala Inc. The humidity device makes use of one transducer electronics section placed in the vicinity of the three (3) humidity sensor heads. The humidity device is mounted on the REMS boom 2 providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The absolute accuracy of the humidity device is temperature dependent, and is of the order of 2% at the temperature range of -30 to -10 °C, and of the order of 10% at the temperature range of -80 to -60 °C. This enables the investigations of atmospheric humidity variations of both diurnal and seasonal scale. The humidity device measurements will have a lag, when a step-wise change in humidity is taking place. This lag effect is increasing with decreasing temperature, and it is of the order of a few hours at the temperature of -75 °C. To compensate for the lag effect we used an algorithm developed by Mäkinen [2]. The humidity observations were validated after tedious efforts. This was needed to compensate for the artifacts of the transducer electronics. The compensation process includes an assumption that the relative humidity at Mars in the temperature range of 0 to -30 °C is about zero. The

  5. Optimization research on the structure of horizontally-arranged indirect air-cooling tower under strong wind condition

    NASA Astrophysics Data System (ADS)

    Chen, Guoyong; Gu, Hongfang; Wang, Haijun; Qin, Yongbo

    2013-07-01

    Strong wind has a significant impact on the heat radiation of the air-cooling system. In this research, a numerical calculation model of 2×1000MW horizontally arranged air-cooling tower is established to simulate the flow distribution and heat exchanging capability of three different structures-horizontally-arranged indirect air-cooling tower, tower with guide wall outside, and tower with a cross wall inside-under high-speed wind and extreme-speed wind conditions. The result reveals that the structure with the guide wall outside the tower only works under strong wind condition while the structure with cross wall inside shows the anti-wind capability under both high-speed wind and extreme-speed wind conditions.

  6. Evolution of arched roofs in salt caves: Role of gravity-induced stress and relative air humidity and temperature changes (Zagros Mts., Iran)

    NASA Astrophysics Data System (ADS)

    Bruthans, Jiri; Filippi, Michal; Zare, Mohammad

    2016-04-01

    In salt caves in the halite karst in SE Iran the disintegration of rock salt into individual grains can be observed. Highly disintegrated blocks and individual grains form a major volume of debris in many caves on islands in the Persian Gulf. Larger cave rooms have often perfectly arched roof. The perfect geometry of rooms and interlocking of salt grains indicate that evolution of room cross-sections in these caves is controlled by feedback between gravity-induced stress and rock salt disintegration in similar way as in evolution of sandstone landforms (Bruthans et al. 2014). Those portions of rock salt, which are under compressional stress, disintegrate much slower than portions under tensile stress. Important question is the kind of weathering mechanism responsible for intergranular disintegration of rock salt. The relationship between disintegration, its rate and cave climate was studied. Clearly the fastest disintegration rate was found in caves with strong air circulation (i.e, short caves with large cross-sections, open on both ends). Temperature and air humidity changes are considerable in these caves. On the other hand the disintegration is very slow in the inner parts of long caves with slow air circulation or caves with one entrance. The best example of such caves is the inner part of 3N Cave on Namakdan salt diapir with nearly no air circulation and stable temperature and humidity, where disintegration of rock salt into grains is missing. Strong effect of cave climate on disintegration rate can be explained by deliquescence properties of halite. Halite is absorbing air moisture forming NaCl solution if relative humidity (RH) exceeds 75 % (at 20-30 oC). In the Persian Gulf region the RH of the air is passing the 75 % threshold in case of 91% days (Qeshm Island, years 2002-2005), while in mountainous areas in mainland this threshold is less commonly reached. In most of nights (91 %) in Persian Gulf the air with RH >75 % is entering the salt caves and air

  7. A laser Doppler system for the remote sensing of boundary layer winds in clear air conditions

    NASA Technical Reports Server (NTRS)

    Lawrence, T. R.; Krause, M. C.; Craven, C. E.; Morrison, L. K.; Thomson, J. A. L.; Cliff, W. C.; Huffaker, R. M.

    1975-01-01

    The system discussed uses a laser Doppler radar in combination with a velocity azimuth display mode of scanning to determine the three-dimensional wind field in the atmospheric boundary layer. An attractive feature of this CW monostatic system is that the ambient aerosol provides a 'sufficient' scattering target to permit operation under clear air conditions. Spatial resolution is achieved by focusing.

  8. Wind Tunnel Evaluation of Vegetative Buffer Effects on Air Flow near Swine Production Facilities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing concerns about generation and transport of swine odor constituents have substantiated wind tunnel simulation studies on air flow dynamics near swine production facilities. A possible odor mitigation strategy is a forest vegetative buffer as a windbreak barrier near swine facilities becaus...

  9. [Effect of air humidity on traditional Chinese medicine extract of spray drying process and prediction of its powder stability].

    PubMed

    He, Yan; Xie, Yin; Zheng, Long-jin; Liu, Wei; Rao, Xiao-yong; Luo, Xiao-jian

    2015-02-01

    In order to solve the adhesion and the softening problems of traditional Chinese medicine extract during spray drying, a new method of adding dehumidified air into spray drying process was proposed, and the storage stability conditions of extract powder could be predicted. Kouyanqing extract was taken as model drug to investigate on the wet air (RH = 70%) and dry air conditions of spray drying. Under the dry air condition, the influence of the spray drying result with different air compression ratio and the spray-dried powder properties (extract powder recovery rate, adhesion percentage, water content, angle of repose, compression ratio, particle size and distribution) with 100, 110, 120, 130, 140 °C inlet temperature were studied. The hygroscopic investigation and Tg value with different moisture content of ideal powder were determined. The water activity-equilibrium moisture content (aw-EMC) and the equilibrium moisture content-Tg (EMC-Tg) relationships were fitted by GAB equation and Gordon-Taylor model respectively, and the state diagram of kouyanqing powder was obtained to guide the rational storage conditions. The study found that in the condition of dry air, the extract powder water content decreased with the increase of air compression ratio and the spray drying effect with air compression ratio of 100% was the best performance; in the condition of wet air, the extract powder with high water content and low yield, and the value were 4.26% and 16.73 °C, while, in the dry air condition the values were 2.43% and 24.86 °C with the same other instru- ment parameters. From the analysis of kouyanqing powder state diagram, in order to keep the stability, the critical water content of 3.42% and the critical water content of 0.188. As the water decreased Tg value of extract powder is the major problem of causing adhesion and softening during spray drying, it is meaningful to aid dehumidified air during the process. PMID:26084164

  10. Performance prediction of a multi-stage wind tower for indoor cooling

    NASA Astrophysics Data System (ADS)

    Issa, Roy J.; Chang, Byungik

    2012-08-01

    A theoretical model is developed to establish an in-depth understanding of the performance of a three-stage wind tower with a bypass system for indoor cooling in rural dry and hot climates. Model simulations are presented for a wide range of ambient conditions that include inlet wind speed, inlet temperature and relative humidity. Simulation results provide an insight into the desirable water flow rates and air-to-water loadings for comfort zone temperatures and relative humidity levels at the exit of the wind tower. Simulations show wind towers with variable cross-sections provide an increase in the cooling power for the same inlet wind speed, inlet air temperature and relative humidity when compared to wind towers with a constant cross-section. The study shall lead to a better understanding to designing wind towers that are both environmentally friendly and energy efficient.

  11. Statistical Short-Range Guidance for Peak Wind Speed Forecasts at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Dreher, Joseph G.; Crawford, Winifred; Lafosse, Richard; Hoeth, Brian; Burns, Kerry

    2009-01-01

    The peak winds near the surface are an important forecast element for space shuttle landings. As defined in the Flight Rules (FR), there are peak wind thresholds that cannot be exceeded in order to ensure the safety of the shuttle during landing operations. The National Weather Service Spaceflight Meteorology Group (SMG) is responsible for weather forecasts for all shuttle landings, and is required to issue surface average and 10-minute peak wind speed forecasts. They indicate peak winds are a challenging parameter to forecast. To alleviate the difficulty in making such wind forecasts, the Applied Meteorology Unit (AMU) developed a PC-based graphical user interface (GUI) for displaying peak wind climatology and probabilities of exceeding peak wind thresholds for the Shuttle Landing Facility (SLF) at Kennedy Space Center (KSC; Lambert 2003). However, the shuttle occasionally may land at Edwards Air Force Base (EAFB) in southern California when weather conditions at KSC in Florida are not acceptable, so SMG forecasters requested a similar tool be developed for EAFB.

  12. Properties of air mass mixing and humidity in the subtropics from measurements of the D/H isotope ratio of water vapor at the Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Noone, David; Galewsky, Joseph; Sharp, Zachary D.; Worden, John; Barnes, John; Baer, Doug; Bailey, Adriana; Brown, Derek P.; Christensen, Lance; Crosson, Eric; Dong, Feng; Hurley, John V.; Johnson, Leah R.; Strong, Mel; Toohey, Darin; van Pelt, Aaron; Wright, Jonathon S.

    2011-11-01

    Water vapor in the subtropical troposphere plays an important role in the radiative balance, the distribution of precipitation, and the chemistry of the Earth's atmosphere. Measurements of the water vapor mixing ratio paired with stable isotope ratios provide unique information on transport processes and moisture sources that is not available with mixing ratio data alone. Measurements of the D/H isotope ratio of water vapor from Mauna Loa Observatory over 4 weeks in October-November 2008 were used to identify components of the regional hydrological cycle. A mixing model exploits the isotope information to identify water fluxes from time series data. Mixing is associated with exchange between marine boundary layer air and tropospheric air on diurnal time scales and between different tropospheric air masses with characteristics that evolve on the synoptic time scale. Diurnal variations are associated with upslope flow and the transition from nighttime air above the marine trade inversion to marine boundary layer air during daytime. During easterly trade wind conditions, growth and decay of the boundary layer are largely conservative in a regional context but contribute ˜12% of the nighttime water vapor at Mauna Loa. Tropospheric moisture is associated with convective outflow and exchange with drier air originating from higher latitude or higher altitude. During the passage of a moist filament, boundary layer exchange is enhanced. Isotopic data reflect the combination of processes that control the water balance, which highlights the utility for baseline measurements of water vapor isotopologues in monitoring the response of the hydrological cycle to climate change.

  13. Thermal comfort in the humid tropics: Field experiments in air conditioned and naturally ventilated buildings in Singapore

    NASA Astrophysics Data System (ADS)

    de Dear, R. J.; Leow, K. G.; Foo, S. C.

    1991-12-01

    Thermal comfort field experiments were conducted in Singapore in both naturally ventilated highrise residential buildings and air conditioned office buildings. Each of the 818 questionnaire responses was made simultaneously with a detailed set of indoor climatic measurements, and estimates of clothing insulation and metabolic rate. Results for the air conditioned sample indicated that office buildings were overcooled, causing up to one-third of their occupants to experience cool thermal comfort sensations. These observations in air conditioned buildings were broadly consistent with the ISO, ASHRAE and Singapore indoor climatic standards. Indoor climates of the naturally ventilated apartments during the day and early evening were on average three degrees warmer than the ISO comfort standard prescriptions, but caused much less thermal discomfort than expected. Discrepancies between thermal comfort responses in apartment blocks and office buildings are discussed in terms of contemporary perceptual theory.

  14. A Simple Drought Product and Indicator Derived from Temperature and Relative Humidity Observed by the Atmospheric InfraRed Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Granger, S. L.; Behrangi, A.

    2015-12-01

    In the United States, drought results in agricultural losses, impacts to industry, power and energy production, natural resources, municipal water supplies and human health making it one of the costliest natural hazards in the nation. Monitoring drought is therefore critical to help local governments, resource managers, and other groups make effective decisions, yet there is no single definition of drought, and because of the complex nature of drought there is no universal best drought indicator. Remote sensing applications in drought monitoring are advantageous due to the large spatial and temporal frequency of observations, leading to a better understanding of the spatial extent of drought and its duration, and in detecting the onset of drought and its intensity. NASA Earth Observing System (EOS)-era data have potential for monitoring and assessing drought and many are already used either directly or indirectly for drought monitoring. Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) sensor are widely used for agricultural and environmental plant-stress monitoring via the USDM, the VegDRI project and FEWSNet. However there remain underutilized sources of information from NASA satellite observations that may have promise for characterizing and understanding meteorological drought. Once such sensor is NASA's Advanced Infra-Red Sounder (AIRS) aboard the Aqua satellite. AIRS and it's sister sensor the Advanced Microwave Sounding Unit (AMSU) that together provide meteorological information of high relevance to meteorological drought, e.g., profiles of water vapor, surface air temperature, and precipitation. Recent work undertaken to develop simple indicators of drought based on temperature and relative humidity from the AIRS suite of instruments is promising. Although there are more sophisticated indicators developed through the application of a variety of

  15. Radiative-dynamical and microphysical processes of thin cirrus clouds controlling humidity of air entering the stratosphere

    NASA Astrophysics Data System (ADS)

    Dinh, Tra; Fueglistaler, Stephan

    2016-04-01

    Thin cirrus clouds in the tropical tropopause layer (TTL) are of great interest due to their role in the control of water vapor and temperature in the TTL. Previous research on TTL cirrus clouds has focussed mainly on microphysical processes, specifically the ice nucleation mechanism and dehydration efficiency. Here, we use a cloud resolving model to analyse the sensitivity of TTL cirrus characteristics and impacts with respect to microphysical and radiative processes. A steady-state TTL cirrus cloud field is obtained in the model forced with dynamical conditions typical for the TTL (2-dimensional setup with a Kelvin-wave temperature perturbation). Our model results show that the dehydration efficiency (as given by the domain average relative humidity in the layer of cloud occurrence) is relatively insensitive to the ice nucleation mechanism, i.e. homogeneous versus heterogeneous nucleation. Rather, TTL cirrus affect the water vapor entering the stratosphere via an indirect effect associated with the cloud radiative heating and dynamics. Resolving the cloud radiative heating and the radiatively induced circulations approximately doubles the domain average ice mass. The cloud radiative heating is proportional to the domain average ice mass, and the observed increase in domain average ice mass induces a domain average temperature increase of a few Kelvin. The corresponding increase in water vapor entering the stratosphere is estimated to be about 30 to 40%.

  16. Ocean Winds and Turbulent Air-Sea Fluxes Inferred From Remote Sensing

    NASA Technical Reports Server (NTRS)

    Bourassa, Mark A.; Gille, Sarah T.; Jackson, Daren L.; Roberts, J. Brent; Wick, Gary A.

    2010-01-01

    Air-sea turbulent fluxes determine the exchange of momentum, heat, freshwater, and gas between the atmosphere and ocean. These exchange processes are critical to a broad range of research questions spanning length scales from meters to thousands of kilometers and time scales from hours to decades. Examples are discussed (section 2). The estimation of surface turbulent fluxes from satellite is challenging and fraught with considerable errors (section 3); however, recent developments in retrievals (section 3) will greatly reduce these errors. Goals for the future observing system are summarized in section 4. Surface fluxes are defined as the rate per unit area at which something (e.g., momentum, energy, moisture, or CO Z ) is transferred across the air/sea interface. Wind- and buoyancy-driven surface fluxes are called surface turbulent fluxes because the mixing and transport are due to turbulence. Examples of nonturbulent processes are radiative fluxes (e.g., solar radiation) and precipitation (Schmitt et al., 2010). Turbulent fluxes are strongly dependent on wind speed; therefore, observations of wind speed are critical for the calculation of all turbulent surface fluxes. Wind stress, the vertical transport of horizontal momentum, also depends on wind direction. Stress is very important for many ocean processes, including upper ocean currents (Dohan and Maximenko, 2010) and deep ocean currents (Lee et al., 2010). On short time scales, this horizontal transport is usually small compared to surface fluxes. For long-term processes, transport can be very important but again is usually small compared to surface fluxes.

  17. Statistical Short-Range Guidance for Peak Wind Speed Forecasts at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Dreher, Joseph; Crawford, Winifred; Lafosse, Richard; Hoeth, Brian; Burns, Kerry

    2008-01-01

    The peak winds near the surface are an important forecast element for Space Shuttle landings. As defined in the Shuttle Flight Rules (FRs), there are peak wind thresholds that cannot be exceeded in order to ensure the safety of the shuttle during landing operations. The National Weather Service Spaceflight Meteorology Group (SMG) is responsible for weather forecasts for all shuttle landings. They indicate peak winds are a challenging parameter to forecast. To alleviate the difficulty in making such wind forecasts, the Applied Meteorology Unit (AMTJ) developed a personal computer based graphical user interface (GUI) for displaying peak wind climatology and probabilities of exceeding peak-wind thresholds for the Shuttle Landing Facility (SLF) at Kennedy Space Center. However, the shuttle must land at Edwards Air Force Base (EAFB) in southern California when weather conditions at Kennedy Space Center in Florida are not acceptable, so SMG forecasters requested that a similar tool be developed for EAFB. Marshall Space Flight Center (MSFC) personnel archived and performed quality control of 2-minute average and 10-minute peak wind speeds at each tower adjacent to the main runway at EAFB from 1997- 2004. They calculated wind climatologies and probabilities of average peak wind occurrence based on the average speed. The climatologies were calculated for each tower and month, and were stratified by hour, direction, and direction/hour. For the probabilities of peak wind occurrence, MSFC calculated empirical and modeled probabilities of meeting or exceeding specific 10-minute peak wind speeds using probability density functions. The AMU obtained and reformatted the data into Microsoft Excel PivotTables, which allows users to display different values with point-click-drag techniques. The GUT was then created from the PivotTables using Visual Basic for Applications code. The GUI is run through a macro within Microsoft Excel and allows forecasters to quickly display and

  18. Evaluation of Vertically Resolved Water Winds from AIRS using Hurricane Katrina

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Dobkowski, Edwin C.; Gregorich, David T.

    2005-01-01

    The knowledge of wind velocity as a function of altitude is key to weather forecast improvements. The ability of hyperspectral sounders in principle to measure vertically resolved water winds, which has long been recognized, has been tested with Atmospheric Infrared Sounder (AIRS) data. AIRS retrievals of total column water above 300 mb have been correlated with the radiosonde upper-tropospheric wind velocity and moisture data. The excellent correlation is illustrated with results obtained from hurricane Katrina and from the western United States. AIRS is a hyperspectral infrared sounder in low Earth orbit. It was launched in May 2002. We illustrate the use of AIRS data for the measurement of upper tropospheric water by using the 2387/cm CO2 R-branch channel and the 1551/cm water vapor channel. The 2387/cm channel measures the temperature at 300 mb totally independent of water vapor. The weighting function of the 1551/cm channel peaks at 300 mb only under moist conditions; the peak shifts downward (higher temperature) for less water and upward (lower temperature) for more water. The difference between the brightness temperatures bt2387 and bt1551 cancels the local several degree weather related variability of the temperature and measures the component due to the water vapor at 300 mb.

  19. Trajectory Simulations of Upper Tropospheric Humidity

    NASA Technical Reports Server (NTRS)

    Dessler, A. E.; Schoeberl, M. R.; Sherwood, S. C.

    1999-01-01

    We present comparisons of simulations of upper tropospheric humidity at 215 and 146 hPa with satellite measurements. Our model uses diabatic trajectories to advect water vapor from an initial condition of 100% relative humidity to the final state. The model does not allow parcels' relative humidity to exceed 100%, and in this way crudely incorporates condensation. We find that this simple model does a good job of simulating the observations. Sensitivity studies suggest that one must have realistic wind velocities in order to accurately simulate the humidity distribution; microphysical parameterizations seem to be less important. Comparisions between simulations using UKMO and NCEP horizontal winds will be discussed.

  20. Weather Research and Forecasting Model Wind Sensitivity Study at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Bauman, William H., III

    2008-01-01

    NASA prefers to land the space shuttle at Kennedy Space Center (KSC). When weather conditions violate Flight Rules at KSC, NASA will usually divert the shuttle landing to Edwards Air Force Base (EAFB) in Southern California. But forecasting surface winds at EAFB is a challenge for the Spaceflight Meteorology Group (SMG) forecasters due to the complex terrain that surrounds EAFB, One particular phenomena identified by SMG is that makes it difficult to forecast the EAFB surface winds is called "wind cycling". This occurs when wind speeds and directions oscillate among towers near the EAFB runway leading to a challenging deorbit bum forecast for shuttle landings. The large-scale numerical weather prediction models cannot properly resolve the wind field due to their coarse horizontal resolutions, so a properly tuned high-resolution mesoscale model is needed. The Weather Research and Forecasting (WRF) model meets this requirement. The AMU assessed the different WRF model options to determine which configuration best predicted surface wind speed and direction at EAFB, To do so, the AMU compared the WRF model performance using two hot start initializations with the Advanced Research WRF and Non-hydrostatic Mesoscale Model dynamical cores and compared model performance while varying the physics options.

  1. Wind estimation using air data probe measurements to evaluate meteorological measurements made during Space Shuttle entries

    NASA Technical Reports Server (NTRS)

    Kelly, G. M.; Findlay, J. T.; Compton, H. R.

    1982-01-01

    Deterministic and weighted least squares methods for obtaining estimates of the horizontal winds encountered during the Shuttle entry phase are described. The estimates are based on in situ Air Data System (ADS) measurements of angle-of-attack, side-slip angle and true airspeed, in conjunction with inertial trajectory parameters obtained from the post flight trajectory reconstruction. Accuracies in the wind estimates obtained from each method are assessed using both theoretical arguments and flight results. Comparisons of derived winds with meteorological measurements taken during the first three Shuttle entries have demonstrated: (1) the usefulness of the wind estimators for evaluating meteorological measurements below 50 kft, and (2) the potential for adequate wind determinations in the absence of independent wind measurements. Comparisons of STS-3 flight-derived L/D versus predicted values from the LaRC aerodynamic data base are presented from 50 kft to touchdown. These results exemplify the importance of such determinations to enhance the ongoing Shuttle aerodynamic and aerothermodynamic research.

  2. Tide and Wind Forcing of Estuarine Air-Water Gas Transfer

    NASA Astrophysics Data System (ADS)

    Orton, P. M.; Zappa, C. J.; McGillis, W. R.

    2008-12-01

    Recent studies have demonstrated that while gas transfer is primarily driven by wind, tidal currents can drive gas exchange in estuaries. Studies have also shown that the turbulent kinetic energy (TKE) dissipation just below the sea surface is a good proxy for the gas exchange velocity (k) for a wide range of forcing processes (e.g. wind, currents, rain). However, the connection between tidally-driven turbulence and gas exchange has not been investigated in detail. In this study, an autonomous instrumented surface platform deployment and one-dimensional numerical modeling are used to examine the influence of wind, tidal current shear, and water column bottom boundary layer (BBL) growth on gas transfer in an estuary. An autonomous instrumented surface platform was deployed for one month at a shallow site in the Hudson River estuary, measuring wind velocity, water velocity, TKE dissipation, air-water CO2 gradient and flux, and gas transfer velocity. Currents were 0-0.8 m s-1, winds 0-14 m s-1, depths 4.7-6.2 m, significant wave heights 0-0.8 m, and water pCO2 700-1600 μatm during the study. Surveys spanning the entire estuary from 2002 to the present broaden our understanding of tidal currents, stratification and turbulence to the entire estuary, with over a billion acoustic velocity measurements, millions of turbulence measurements, and 50 CTD surveys up the entire length of the estuary. The estuarine observations show a strong relationship between wind and k, but several recent parameterizations of k as a function of wind speed under-predict k for low-to-moderate winds (1-6 m s- 1). Upper water-column TKE dissipation and k are correlated, consistent with a recent parameterization. Both processes show enhancement when the turbulent BBL nears the sea surface. One-dimensional turbulence modeling is used to expand these results to a broad range of estuaries.

  3. Interconversion of chromium species during air sampling: effects of O3, NO2, SO2, particle matrices, temperature, and humidity.

    PubMed

    Huang, Lihui; Fan, Zhihua Tina; Yu, Chang Ho; Hopke, Philip K; Lioy, Paul J; Buckley, Brian T; Lin, Lin; Ma, Yingjun

    2013-05-01

    The interconversion between Cr(VI), a pulmonary carcinogen, and Cr(III), an essential human nutrient, poses challenges to the measurement of Cr(VI) in airborne particles. Chamber and field tests were conducted to identify the factors affecting Cr(VI)-Cr(III) interconversion in the basic filter medium under typical sampling conditions. In the chamber tests, isotopically enriched (53)Cr(VI) and (50)Cr(III) were spiked on diesel particulate matter (DPM) and secondary organic aerosol (SOA) that were precollected on a basic MCE filter. The filter samples were then exposed to clean air or the air containing SO2 (50 and 160 ppb), 100 ppb O3, or 150 ppb NO2 for 24 h at 16.7 LPM flow rate at designated temperature (20 and 31 °C) and RH (40% and 70%) conditions. Exposure to 160 ppb SO2 had the greatest effect on (53)Cr(VI) reduction, with (53)Cr(VI) recovery of 31.7 ± 15.8% (DPM) and 42.0 ± 7.9% (SOA). DPM and SOA matrix induced (53)Cr(VI) reduction when exposed to clean air while reactive oxygen species in SOA could promote (50)Cr(III) oxidation. Deliquescence when RH increased from 40% to 70% led to conversion of Cr(III) in SOA, whereas oxidized organics in DPM and SOA enhanced hygroscopicity and thus facilitated Cr(VI) reduction. Field tests showed seasonal variation of Cr(VI)-Cr(III) interconversion during sampling. Correction of the interconversion using USEPA method 6800 is recommended to improve accuracy of ambient Cr(VI) measurements. PMID:23550818

  4. Effects of Thermal Mass, Window Size, and Night-Time Ventilation on Peak Indoor Air Temperature in the Warm-Humid Climate of Ghana

    PubMed Central

    Amos-Abanyie, S.; Akuffo, F. O.; Kutin-Sanwu, V.

    2013-01-01

    Most office buildings in the warm-humid sub-Saharan countries experience high cooling load because of the predominant use of sandcrete blocks which are of low thermal mass in construction and extensive use of glazing. Relatively, low night-time temperatures are not harnessed in cooling buildings because office openings remain closed after work hours. An optimization was performed through a sensitivity analysis-based simulation, using the Energy Plus (E+) simulation software to assess the effects of thermal mass, window size, and night ventilation on peak indoor air temperature (PIAT). An experimental system was designed based on the features of the most promising simulation model, constructed and monitored, and the experimental data used to validate the simulation model. The results show that an optimization of thermal mass and window size coupled with activation of night-time ventilation provides a synergistic effect to obtain reduced peak indoor air temperature. An expression that predicts, indoor maximum temperature has been derived for models of various thermal masses. PMID:23878528

  5. Air supply using an ionic wind generator in a proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Kwon, Kilsung; Li, Longnan; Park, Byung Ho; Lee, Seung Jun; Kim, Daejoong

    2015-06-01

    A new air supply is demonstrated for a portable polymer electrolyte membrane fuel cell (PEMFC). The air supply is an ionic wind generator (IWG) with a needle-to-cylinder configuration. The IWG supplies air to the portable PEMFC owing to momentum transfer to the air by charged molecules generated by the corona discharge from a high applied potential. There is no difference in the performance of the PEMFC when compressed air and the IWG are used as the air supply. For the varying interelectrode distance, IWG performance is varied and measured in terms of the flow rate and current. At the interelectrode distance of 9.0 mm, the air flow rate is a suitable for the portable PEMFC with low power consumption. When the IWG is used to supply air to the portable PEMFC, it is found that the flow rate per unit power consumed decreases with the applied voltage, the gross power generation monotonously increases with the applied voltage, and the highest net power (268 mW) is obtained at the applied voltage of 8.5 kV. The parasitic power ratio reaches a minimum value of ∼0.06 with the applied IWG voltage of 5.5 kV.

  6. Vertical air circulation in a low-speed lateral flow wind turbine with rotary blades

    NASA Astrophysics Data System (ADS)

    Cheboxarov, Vik. V.; Cheboxarov, Val. V.

    2008-01-01

    The model of a large-scale lateral flow wind turbine with rotary blades is presented and the conditions of numerical aerodynamic investigation of this turbine are described. The results of numerical experiments show that air flowing past the turbine exhibits a considerable vertical (axial) circulation, which increases the power coefficient of the turbine. In the inner space of the turbine, two stable vortices are formed through which retarded streams partly leave the turbine upon flowing past the windward side, to be replaced by faster streams from adjacent layers of air.

  7. Estimation of potential evapotranspiration from extraterrestrial radiation, air temperature and humidity to assess future climate change effects on the vegetation of the Northern Great Plains, USA

    USGS Publications Warehouse

    King, David A.; Bachelet, Dominique M.; Symstad, Amy J.; Ferschweiler, Ken; Hobbins, Michael

    2014-01-01

    The potential evapotranspiration (PET) that would occur with unlimited plant access to water is a central driver of simulated plant growth in many ecological models. PET is influenced by solar and longwave radiation, temperature, wind speed, and humidity, but it is often modeled as a function of temperature alone. This approach can cause biases in projections of future climate impacts in part because it confounds the effects of warming due to increased greenhouse gases with that which would be caused by increased radiation from the sun. We developed an algorithm for linking PET to extraterrestrial solar radiation (incoming top-of atmosphere solar radiation), as well as temperature and atmospheric water vapor pressure, and incorporated this algorithm into the dynamic global vegetation model MC1. We tested the new algorithm for the Northern Great Plains, USA, whose remaining grasslands are threatened by continuing woody encroachment. Both the new and the standard temperature-dependent MC1 algorithm adequately simulated current PET, as compared to the more rigorous PenPan model of Rotstayn et al. (2006). However, compared to the standard algorithm, the new algorithm projected a much more gradual increase in PET over the 21st century for three contrasting future climates. This difference led to lower simulated drought effects and hence greater woody encroachment with the new algorithm, illustrating the importance of more rigorous calculations of PET in ecological models dealing with climate change.

  8. Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

    SciTech Connect

    Johnson, Michael J.; Go, David B.

    2015-12-28

    To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ∼30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (<30 V) to generate breakdown in air without the need for conventional high-voltage electrical equipment. Piezoelectric transformers (PTs) use their inherent electromechanical resonance to produce a voltage amplification, such that the surface of the piezoelectric exhibits a large surface voltage that can generate corona-like discharges on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.

  9. Piezoelectric transformers for low-voltage generation of gas discharges and ionic winds in atmospheric air

    NASA Astrophysics Data System (ADS)

    Johnson, Michael J.; Go, David B.

    2015-12-01

    To generate a gas discharge (plasma) in atmospheric air requires an electric field that exceeds the breakdown threshold of ˜30 kV/cm. Because of safety, size, or cost constraints, the large applied voltages required to generate such fields are often prohibitive for portable applications. In this work, piezoelectric transformers are used to amplify a low input applied voltage (<30 V) to generate breakdown in air without the need for conventional high-voltage electrical equipment. Piezoelectric transformers (PTs) use their inherent electromechanical resonance to produce a voltage amplification, such that the surface of the piezoelectric exhibits a large surface voltage that can generate corona-like discharges on its corners or on adjacent electrodes. In the proper configuration, these discharges can be used to generate a bulk air flow called an ionic wind. In this work, PT-driven discharges are characterized by measuring the discharge current and the velocity of the induced ionic wind with ionic winds generated using input voltages as low as 7 V. The characteristics of the discharge change as the input voltage increases; this modifies the resonance of the system and subsequent required operating parameters.

  10. Wind tunnel experiments: cold-air pooling and atmospheric decoupling above a melting snow patch

    NASA Astrophysics Data System (ADS)

    Mott, R.; Paterna, E.; Horender, S.; Crivelli, P.; Lehning, M.

    2015-10-01

    The longevity of perennial snow fields is not fully understood but it is known that strong atmospheric stability and thus boundary layer decoupling limits the amount of (sensible and latent) heat that can be transmitted to the snow surface. The strong stability is typically caused by two factors, (i) the temperature difference between the (melting) snow surface and the near-surface atmosphere and (ii) cold-air pooling in topographic depressions. These factors are almost always a prerequisite for perennial snow fields to exist. For the first time, this contribution investigates the relative importance of the two factors in a controlled wind tunnel environment. Vertical profiles of sensible heat fluxes are measured using two-component hot wire and one-component cold-wire anemometry directly over the melting snow patch. The comparison between a flat snow surface and one that has a depression shows that atmospheric decoupling is strongly increased in the case of topographic sheltering but only for low to moderate wind speeds. For those conditions, the near-surface suppression of turbulent mixing was observed to be strongest and drainage flows were decoupled from the surface enhancing atmospheric stability and promoting the cold-air pooling over the single snow patch. Further work is required to systematically and quantitatively describe the flux distribution for varying terrain geometry, wind speeds and air temperatures.

  11. Wind driven vertical transport in a vegetated, wetland water column with air-water gas exchange

    NASA Astrophysics Data System (ADS)

    Poindexter, C.; Variano, E. A.

    2010-12-01

    Flow around arrays of cylinders at low and intermediate Reynolds numbers has been studied numerically, analytically and experimentally. Early results demonstrated that at flow around randomly oriented cylinders exhibits reduced turbulent length scales and reduced diffusivity when compared to similarly forced, unimpeded flows (Nepf 1999). While horizontal dispersion in flows through cylinder arrays has received considerable research attention, the case of vertical dispersion of reactive constituents has not. This case is relevant to the vertical transfer of dissolved gases in wetlands with emergent vegetation. We present results showing that the presence of vegetation can significantly enhance vertical transport, including gas transfer across the air-water interface. Specifically, we study a wind-sheared air-water interface in which randomly arrayed cylinders represent emergent vegetation. Wind is one of several processes that may govern physical dispersion of dissolved gases in wetlands. Wind represents the dominant force for gas transfer across the air-water interface in the ocean. Empirical relationships between wind and the gas transfer coefficient, k, have been used to estimate spatial variability of CO2 exchange across the worlds’ oceans. Because wetlands with emergent vegetation are different from oceans, different model of wind effects is needed. We investigated the vertical transport of dissolved oxygen in a scaled wetland model built inside a laboratory tank equipped with an open-ended wind tunnel. Plastic tubing immersed in water to a depth of approximately 40 cm represented emergent vegetation of cylindrical form such as hard-stem bulrush (Schoenoplectus acutus). After partially removing the oxygen from the tank water via reaction with sodium sulfite, we used an optical probe to measure dissolved oxygen at mid-depth as the tank water re-equilibrated with the air above. We used dissolved oxygen time-series for a range of mean wind speeds to estimate the

  12. The Effect of Venue and Wind on the Distance of a Hammer Throw

    ERIC Educational Resources Information Center

    Hunter, Iain

    2005-01-01

    In track and field, gravity and air resistance act on the hammer after it has been released. Both of these forces depend on altitude and latitude. In addition, air resistance also depends on wind, temperature, humidity, and barometric pressure. Often, air resistance and varying gravity throughout the earth are not considered when throwing…

  13. An analysis of winds affecting air pollution concentrations in Hong Kong

    NASA Astrophysics Data System (ADS)

    Cheng, Shouquan; Lam, Kin-Che

    A study of concentrations of SO 2 and TSP has been performed in Hong Kong. The results were discussed from the standpoint of seasonal, monthly, and weekly variations and wind effects. The monthly mean SO 2 concentrations were in the range of 16.6-43.7 μg m -3 and showed regular seasonal variations with the highest concentrations in summer and the lowest in autumn. On the other hand, the monthly TSP concentrations reached the highest (117.7 μg m -3) in December and the lowest (72.9 μg m -3) in June. The procedure was able to identify that the high SO 2 concentrations were generally associated with the southwesterly and westerly winds, while the high TSP concentrations were usually related to the northerly and westerly winds. From 1983 to 1992, 85% of the total high and severe SO 2 concentration days were observed when there were the SSW-WNW winds over Hong Kong; and 70% of the total severe TSP concentration days occurred in the days with the W-ENE winds. Finally, the proportion of the total SO 2 concentrations contributed by each of the source regions was quantitatively estimated. On an average the power stations, industry, and automobiles, etc., are responsible for 40, 35, and 25% of the total SO 2 concentrations in the urban air of Hong Kong, respectively.

  14. LOCATING NEARBY SOURCES OF AIR POLLUTION BY NONPARAMETRIC REGRESSION OF ATMOSPHERIC CONCENTRATIONS ON WIND DIRECTION. (R826238)

    EPA Science Inventory

    The relationship of the concentration of air pollutants to wind direction has been determined by nonparametric regression using a Gaussian kernel. The results are smooth curves with error bars that allow for the accurate determination of the wind direction where the concentrat...

  15. Air/sea DMS gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

    NASA Astrophysics Data System (ADS)

    Bell, T. G.; De Bruyn, W.; Miller, S. D.; Ward, B.; Christensen, K.; Saltzman, E. S.

    2013-05-01

    Shipboard measurements of eddy covariance DMS air/sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s-1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air/sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near surface water side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air/sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.

  16. Calibration of a system for measuring low air flow velocity in a wind tunnel

    NASA Astrophysics Data System (ADS)

    Krach, Andrzej; Kruczkowski, Janusz

    2016-08-01

    This article presents the calibration of a system for measuring air flow velocity in a wind tunnel with a multiple-hole orifice. The comparative method was applied for the calibration. The method consists in equalising the air flow velocity in a test section of the tunnel with that of the hot-wire anemometer probe which should then read zero value. The hot-wire anemometer probe moves reciprocally in the tunnel test section with a constant velocity, aligned and opposite to the air velocity. Air velocity in the tunnel test section is adjusted so that the minimum values of a periodic hot-wire anemometer signal displayed on an oscilloscope screen reach the lowest position (the minimum method). A sinusoidal component can be superimposed to the probe constant velocity. Then, the air flow velocity in the tunnel test section is adjusted so that, when the probe moves in the direction of air flow, only the second harmonic of the periodically variable velocity superimposed on the constant velocity (second harmonic method) remains at the output of the low-pass filter to which the hot-wire anemometer signal, displayed on the oscilloscope screen, is supplied. The velocity of the uniform motion of the hot-wire anemometer probe is measured with a magnetic linear encoder. The calibration of the system for the measurement of low air velocities in the wind tunnel was performed in the following steps: 1. Calibration of the linear encoder for the measurement of the uniform motion velocity of the hot-wire anemometer probe in the test section of the tunnel. 2. Calibration of the system for measurement of low air velocities with a multiple-hole orifice for the velocities of 0.1 and 0.25 m s‑1: - (a) measurement of the probe movement velocity setting; - (b) measurement of air velocity in the tunnel test section with comparison according to the second harmonic method; - (c) measurement of air velocity in the tunnel with comparison according to the minimum method. The calibration

  17. Manganese oxide octahedral molecular sieve K-OMS-2 as catalyst in post plasma-catalysis for trichloroethylene degradation in humid air.

    PubMed

    Nguyen Dinh, M T; Giraudon, J-M; Vandenbroucke, A M; Morent, R; De Geyter, N; Lamonier, J-F

    2016-08-15

    The total oxidation of trichloroethylene (TCE) in air at low relative humidity (RH=10%) in the presence of CO2 (520ppmv) was investigated in function of energy density using an atmospheric pressure negative DC luminescent glow discharge combined with a cryptomelane catalyst positioned downstream of the plasma reactor at a temperature of 150°C. When using Non-Thermal Plasma (NTP) alone, it is found a low COx (x=1-2) yield in agreement with the detection of gaseous polychlorinated by-products in the outlet stream as well as ozone which is an harmful pollutant. Introduction of cryptomelane enhanced trichloroethylene removal, totally inhibited plasma ozone formation and increased significantly the COx yield. The improved performances of the hybrid system were mainly ascribed to the total destruction of plasma generated ozone on cryptomelane surface to produce active oxygen species. Consequently these active oxygen species greatly enhanced the abatement of the plasma non-reacted TCE and completely destroyed the hazardous plasma generated polychlorinated intermediates. The facile redox of Mn species associated with oxygen vacancies and mobility as well as the textural properties of the catalyst might also contribute as a whole to the efficiency of the process. PMID:27107238

  18. A theoretical model for {sup 222}Rn adsorption on activated charcoal canisters in humid air based on Polanyi`s potential theory

    SciTech Connect

    Scarpitta, S.C.

    1995-03-01

    Water vapor interferes with adsorption {sup 222}Rn gas by passive activated charcoal devices used to estimate indoor air concentrations. The {sup 222}Rn adsorption coefficient is the fundamental parameter characterizing charcoal`s ability to adsorb {sup 222}Rn. The Dubinin-Radushkevich equation, based on Polanyi`s potential theory, was modified to include two terms quantifying the effect of both water vapor and sampling time on the {sup 222}Rn adsorption coefficient of passive charcoal devices. A single equation was derived that quantities the {sup 222}Rn adsorption coefficients at any temperature, humidity and exposure time using six experimentally determined physical constants that are unique for a particular passive charcoal device. The theoretical model was verified with published experimental data, and it showed a good correlation between theory and experiment. The model proved to be consistent with experimental data, provided that the amount of water vapor adsorbed by the charcoal device during sampling remains below a critical level, termed the breakpoint. 44 refs., 5 figs., 2 tabs.

  19. Energy and economic assessment of desiccant cooling systems coupled with single glazed air and hybrid PV/thermal solar collectors for applications in hot and humid climate

    SciTech Connect

    Beccali, Marco; Finocchiaro, Pietro; Nocke, Bettina

    2009-10-15

    This paper presents a detailed analysis of the energy and economic performance of desiccant cooling systems (DEC) equipped with both single glazed standard air and hybrid photovoltaic/thermal (PV/t) collectors for applications in hot and humid climates. The use of 'solar cogeneration' by means of PV/t hybrid collectors enables the simultaneous production of electricity and heat, which can be directly used by desiccant air handling units, thereby making it possible to achieve very energy savings. The present work shows the results of detailed simulations conducted for a set of desiccant cooling systems operating without any heat storage. System performance was investigated through hourly simulations for different systems and load combinations. Three configurations of DEC systems were considered: standard DEC, DEC with an integrated heat pump and DEC with an enthalpy wheel. Two kinds of building occupations were considered: office and lecture room. Moreover, three configurations of solar-assisted air handling units (AHU) equipped with desiccant wheels were considered and compared with standard AHUs, focusing on achievable primary energy savings. The relationship between the solar collector's area and the specific primary energy consumption for different system configurations and building occupation patterns is described. For both occupation patterns, sensitivity analysis on system performance was performed for different solar collector areas. Also, this work presents an economic assessment of the systems. The cost of conserved energy and the payback time were calculated, with and without public incentives for solar cooling systems. It is worth noting that the use of photovoltaics, and thus the exploitation of related available incentives in many European countries, could positively influence the spread of solar air cooling technologies (SAC). An outcome of this work is that SAC systems equipped with PV/t collectors are shown to have better performance in terms of

  20. Peak Wind Forecasts for the Launch-Critical Wind Towers on Kennedy Space Center/Cape Canaveral Air Force Station, Phase IV

    NASA Technical Reports Server (NTRS)

    Crawford, Winifred

    2011-01-01

    This final report describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The peak winds arc an important forecast clement for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to update the statistics in the current peak-wind forecast tool to assist in forecasting LCC violations. The tool includes onshore and offshore flow climatologies of the 5-minute mean and peak winds and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  1. Raman diagnostic of the reactivity between ZnSO4 and CaCO3 particles in humid air relevant to heterogeneous zinc chemistry in atmosphere

    NASA Astrophysics Data System (ADS)

    Falgayrac, Guillaume; Sobanska, Sophie; Brémard, Claude

    2014-03-01

    Laboratory experiments using Raman imaging demonstrated the behaviour of ZnSO4·7H2O (goslarite) microparticles in contact with a {101bar4} CaCO3 (calcite) surface under three different experimental conditions representative of remote atmosphere. Contact between the ZnSO4·7H2O particles and the CaCO3 surface in humid air (RH ∼40-80%) did not induce any deliquescence and chemical phenomena. In contrast, condensation of a water drop at the ZnSO4·7H2O-CaCO3 interface caused free dissolution of the ZnSO4·7H2O particle and rapid precipitation of Zn4SO4(OH)6 onto the CaCO3 surface. This coating inhibited the surface reaction and subsequent drying resulted in the deposition of residual ZnSO4·7H2O, then ZnSO4·H2O (gunningite) and CaSO4·2H2O (gypsum) superimposed onto the Zn4SO4(OH)6 layer. The deposition of ZnSO4·7H2O particles in a water drop, previously in contact with a CaCO3 particle for a long time, resulted in the coprecipitation of Zn4SO4(OH)6 and Zn5(CO3)2(OH)6 (hydrozincite). Subsequent drying caused the deposition of residual ZnSO4·7H2O, ZnSO4·H2O and CaSO4·2H2O as small particles. These results indicated the possible fates of ZnSO4 particles in a humid atmosphere, when externally mixed with CaCO3 mineral dust after atmospheric events such as aggregation, water condensation and evaporation. This study indicated the fundamental role of water that typically existed on the surface of aerosol particles in the troposphere. These heterogeneous chemical processes have substantial consequences on particle size and solubility, and thus on bioavailability and toxicity of metal-rich particles.

  2. UAS Air Traffic Controller Acceptability Study-2: Effects of Communications Delays and Winds in Simulation

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; Ghatas, Rania W.; Consiglio, Maria C.; Chamberlain, James P.; Hoffler, Keith D.

    2016-01-01

    This study evaluated the effects of Communications Delays and Winds on Air Traffic Controller ratings of acceptability of horizontal miss distances (HMDs) for encounters between UAS and manned aircraft in a simulation of the Dallas-Ft. Worth East-side airspace. Fourteen encounters per hour were staged in the presence of moderate background traffic. Seven recently retired controllers with experience at DFW served as subjects. Guidance provided to the UAS pilots for maintaining a given HMD was provided by information from self-separation algorithms displayed on the Multi-Aircraft Simulation System. Winds tested did not affect the acceptability ratings. Communications delays tested included 0, 400, 1200, and 1800 msec. For longer communications delays, there were changes in strategy and communications flow that were observed and reported by the controllers. The aim of this work is to provide useful information for guiding future rules and regulations applicable to flying UAS in the NAS.

  3. Simulating smoke transport from wildland fires with a regional-scale air quality model: Sensitivity to uncertain wind fields

    NASA Astrophysics Data System (ADS)

    Garcia-Menendez, Fernando; Hu, Yongtao; Odman, Mehmet Talat

    2013-06-01

    Uncertainties associated with meteorological inputs which are propagated through atmospheric chemical transport models may constrain their ability to replicate the effects of wildland fires on air quality. Here, we investigate the sensitivity of predicted fine particulate matter (PM2.5) levels to uncertain wind fields by simulating the air quality impacts of two fires on an urban area with the Community Multiscale Air Quality modeling system (CMAQ). Brute-force sensitivity analyses show that modeled concentrations at receptors downwind from the fires are highly sensitive to variations in wind speed and direction. Additionally, uncertainty in wind fields produced with the Weather Research and Forecasting model was assessed by evaluating meteorological predictions against surface and upper air observations. Significant differences between predicted and observed wind fields were identified. Simulated PM2.5 concentrations at urban sites displayed large sensitivities to wind perturbations within the error range of meteorological inputs. The analyses demonstrate that normalized errors in CMAQ predictions attempting to model the regional impacts of fires on PM2.5 levels could be as high as 100% due to inaccuracies in wind data. Meteorological drivers may largely account for the considerable discrepancies between monitoring site observations and predicted concentrations. The results of this study demonstrate that limitations in fire-related air quality simulations cannot be overcome by solely improving emission rates.

  4. Effect of Wind Tunnel Air Velocity on VOC Flux from Standard Solutions and CAFO Manure/Wastewater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers and practitioners have used wind tunnels and flux chambers to quantify the flux of volatile organic compounds (VOCs), ammonia, and hydrogen sulfide and estimate emission factors from animal feeding operations (AFOs) without accounting for effects of air velocity or sweep air flow rate. L...

  5. Humidity-dependent compression-induced glass transition of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA).

    PubMed

    Kim, Hyun Chang; Lee, Hoyoung; Jung, Hyunjung; Choi, Yun Hwa; Meron, Mati; Lin, Binhua; Bang, Joona; Won, You-Yeon

    2015-07-28

    Constant rate compression isotherms of the air-water interfacial Langmuir films of poly(D,L-lactic acid-ran-glycolic acid) (PLGA) show a distinct feature of an exponential increase in surface pressure in the high surface polymer concentration regime. We have previously demonstrated that this abrupt increase in surface pressure is linked to the glass transition of the polymer film, but the detailed mechanism of this process is not fully understood. In order to obtain a molecular-level understanding of this behavior, we performed extensive characterizations of the surface mechanical, structural and rheological properties of Langmuir PLGA films at the air-water interface, using combined experimental techniques including the Langmuir film balance, X-ray reflectivity and double-wall-ring interfacial rheometry methods. We observed that the mechanical and structural responses of the Langmuir PLGA films are significantly dependent on the rate of film compression; the glass transition was induced in the PLGA film only at fast compression rates. Surprisingly, we found that this deformation rate dependence is also dependent on the humidity of the environment. With water acting as a plasticizer for the PLGA material, the diffusion of water molecules through the PLGA film seems to be the key factor in the determination of the glass transformation properties and thus the mechanical response of the PLGA film against lateral compression. Based on our combined results, we hypothesize the following mechanism for the compression-induced glass transformation of the Langmuir PLGA film; (1) initially, a humidified/non-glassy PLGA film is formed in the full surface-coverage region (where the surface pressure shows a plateau) during compression; (2) further compression leads to the collapse of the PLGA chains and the formation of new surfaces on the air side of the film, and this newly formed top layer of the PLGA film is transiently glassy in character because the water evaporation rate

  6. A 2-Liter, 2000 MPa Air Source for the Radiatively Driven Hypersonic Wind Tunnel

    SciTech Connect

    Costantino, M; Lofftus, D

    2002-05-30

    The A2 LITE is a 2 liter, 2000 MPa, 750 K ultra-high pressure (UHP) vessel used to demonstrate UHP technology and to provide an air flow for wind tunnel nozzle development. It is the largest volume UHP vessel in the world. The design is based on a 100:1 pressure intensification using a hydraulic ram as a low pressure driver and a three-layer compound cylinder UHP section. Active control of the 900 mm piston stroke in the 63.5 mm bore permits pressure-time profiles ranging from static to constant pressure during flow through a 1 mm throat diameter nozzle for 1 second.

  7. ABA induces H2O2 production in guard cells, but does not close the stomata on Vicia faba leaves developed at high air humidity

    PubMed Central

    Arve, Louise E; Carvalho, Dália RA; Olsen, Jorunn E; Torre, Sissel

    2014-01-01

    Plants developed under constant high (> 85%) relative air humidity (RH) have larger stomata that are unable to close completely. One of the hypotheses for the less responsive stomata is that the plants have reduced sensitivity to abscisic acid (ABA). Both ABA and darkness are signals for stomatal closure and induce the production of the secondary messenger hydrogen peroxide (H2O2). In this study, the ability of Vicia faba plants developed in moderate or high RH to close the stomata in response to darkness, ABA and H2O2 was investigated. Moreover, the ability of the plants to produce H2O2 when treated with ABA or transferred to darkness was also assessed. Our results show that the ABA concentration in moderate RH is not increased during darkness even though the stomata are closing. This indicates that stomatal closure in V. faba during darkness is independent of ABA production. ABA induced both H2O2 production and stomatal closure in stomata formed at moderate RH. H2O2 production, as a result of treatment with ABA, was also observed in stomata formed at high RH, though the closing response was considerably smaller as compared with moderate RH. In either RH, leaf ABA concentration was not affected by darkness. Similarly to ABA treatment, darkness elicited both H2O2 production and stomatal closure following plant cultivation at moderate RH. Contrary to this, neither H2O2 production nor stomatal closure took place when stomata were formed at high RH. These results suggest that the reduced stomatal response in plants developed in continuous high RH is caused by one or more factors downstream of H2O2 in the signaling pathway toward stomatal closure. PMID:25763494

  8. Predictability of the Indian Summer Monsoon onset through an analysis of variations in surface air temperature and relative humidity during the pre-monsoon season

    NASA Astrophysics Data System (ADS)

    Stolbova, V.; Surovyatkina, E.; Bookhagen, B.; Kurths, J.

    2014-12-01

    The prediction of the Indian Summer monsoon (ISM) onset is one of the vital questions for the Indian subcontinent, as well as for areas directly or indirectly affected by the ISM. In previous studies, the areas used for ISM-onset prediction were often too large (or too small), or did not include all necessary information for the ISM-onset forecasting. Here, we present recent findings that suggest that a climate network approach may help to provide better definitions for areas used for ISM-onset prediction and an overall better ISM-onset prediction. Our analysis focuses on the following domains: North West Pakistan (NP) and the Eastern Ghats (EG) as they have been identified to include important pre-monsoon information for predicting ISM onset dates. Specifically, we focus on the analysis of surface air temperature and relative humidity in both areas that allows us to derive temporal trends and to estimate the ISM onset. We propose an approach, which allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In addition, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the forthcoming ISM will be normal or weaker/stronger.

  9. Weather Research and Forecasting Model Wind Sensitivity Study at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.; Bauman, William H., III; Hoeth, Brian

    2009-01-01

    This abstract describes work that will be done by the Applied Meteorology Unit (AMU) in assessing the success of different model configurations in predicting "wind cycling" cases at Edwards Air Force Base, CA (EAFB), in which the wind speeds and directions oscillate among towers near the EAFB runway. The Weather Research and Forecasting (WRF) model allows users to choose among two dynamical cores - the Advanced Research WRF (ARW) and the Non-hydrostatic Mesoscale Model (NMM). There are also data assimilation analysis packages available for the initialization of the WRF model - the Local Analysis and Prediction System (LAPS) and the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS). Having a series of initialization options and WRF cores, as well as many options within each core, creates challenges for local forecasters, such as determining which configuration options are best to address specific forecast concerns. The goal of this project is to assess the different configurations available and determine which configuration will best predict surface wind speed and direction at EAFB.

  10. Cold air outbreaks along a non-frozen sea channel: effects of wind on snow bands

    NASA Astrophysics Data System (ADS)

    Savijärvi, Hannu

    2015-08-01

    Wintertime cold air outbreaks along a non-frozen sea channel or a long lake can become destructive if the related bands of heavy snowfall hit onto land. The forcing for such bands is studied with a 2D numerical model set across an east-west sea channel at 60oN (`Gulf of Finland'), varying the basic geostrophic wind V g. Without any V g opposite coastal land breezes emerge with convergence. This results in a quasi-steady rising motion w max ~ 7.5 cm/s at 600 m in the middle of the gulf, which can force a snow band. During weak V g, the rising motion is reduced but least so for winds from 60o to 80o (~ENE), when modest alongshore bands could exist near the downstream (Estonian) coast. During V g of 4-6 m/s from any direction, the land breezes and rising motions are reduced more effectively, so snow bands are not expected during moderate basic flow. In contrast, during a strong V g of 20-25 m/s from 110o to 120o (~ESE) the land breeze perturbations are intense with w max up to 15-18 cm/s. The induced alongshore bands of heavy snowfall are located in these cases at the sea but quite close to the downstream (Finnish) coast. They can suddenly make a landfall if the basic wind turns clockwise.

  11. Numerical implementation and oceanographic application of the thermodynamic potentials of liquid water, water vapour, ice, seawater and humid air - Part 2: The library routines

    NASA Astrophysics Data System (ADS)

    Wright, D. G.; Feistel, R.; Reissmann, J. H.; Miyagawa, K.; Jackett, D. R.; Wagner, W.; Overhoff, U.; Guder, C.; Feistel, A.; Marion, G. M.

    2010-07-01

    The SCOR/IAPSO1 Working Group 127 on Thermodynamics and Equation of State of Seawater has prepared recommendations for new methods and algorithms for numerical estimation of the the thermophysical properties of seawater. As an outcome of this work, a new International Thermodynamic Equation of Seawater (TEOS-10) was endorsed by IOC/UNESCO2 in June 2009 as the official replacement and extension of the 1980 International Equation of State, EOS-80. As part of this new standard a source code package has been prepared that is now made freely available to users via the World Wide Web. This package includes two libraries referred to as the SIA (Sea-Ice-Air) library and the GSW (Gibbs SeaWater) library. Information on the GSW library may be found on the TEOS-10 web site (http://www.TEOS-10.org). This publication provides an introduction to the SIA library which contains routines to calculate various thermodynamic properties as discussed in the companion paper. The SIA library is very comprehensive, including routines to deal with fluid water, ice, seawater and humid air as well as equilibrium states involving various combinations of these, with equivalent code developed in different languages. The code is hierachically structured in modules that support (i) almost unlimited extension with respect to additional properties or relations, (ii) an extraction of self-contained sub-libraries, (iii) separate updating of the empirical thermodynamic potentials, and (iv) code verification on different platforms and between different languages. Error trapping is implemented to identify when one or more of the primary routines are accessed significantly beyond their established range of validity. The initial version of the SIA library is available in Visual Basic and FORTRAN as a supplement to this publication and updates will be maintained on the TEOS-10 web site. 1SCOR/IAPSO: Scientific Committee on Oceanic Research

  12. The Use of Red Green Blue Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Zavodsky, B. T.; Jedlovec, G. J.; Molthan, A. L.

    2013-01-01

    Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis, and Rapid Refresh analyses.

  13. Air-Loads Prediction of a UH-60A Rotor inside the 40- by 80-Foot Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Chang, I-Chung; Romander, Ethan A.; Potsdam, Mark; Yeo, Hyeonsoo

    2010-01-01

    The presented research extends the capability of a loose coupling computational fluid dynamics (CFD) and computational structure dynamics (CSD) code to calculate the flow-field around a rotor and test stand mounted inside a wind tunnel. Comparison of predicted air-load results for a full-scale UH-60A rotor recently tested inside the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel at Ames Research Center and in free-air flight are made for three challenging flight data points from the earlier conducted UH-60A Air-loads Program. Overall results show that the extension of the coupled CFD/CSD code to the wind-tunnel environment is generally successful.

  14. Developing a Peak Wind Probability Forecast Tool for Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Lambert, WInifred; Roeder, William

    2007-01-01

    This conference presentation describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida. The peak winds are an important forecast element for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a short-range peak-wind forecast tool to assist in forecasting LCC violations. The tool will include climatologies of the 5-minute mean and peak winds by month, hour, and direction, and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  15. Using wind setdown and storm surge on Lake Erie to calibrate the air-sea drag coefficient.

    PubMed

    Drews, Carl

    2013-01-01

    The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

  16. Using Wind Setdown and Storm Surge on Lake Erie to Calibrate the Air-Sea Drag Coefficient

    PubMed Central

    Drews, Carl

    2013-01-01

    The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

  17. Preliminary Assessment of Potential Avian Interactions at Four Proposed Wind Energy Facilities on Vandenberg Air Force Base, California

    SciTech Connect

    Not Available

    2004-08-01

    The United States Air Force (USAF) is investigating whether to install wind turbines to provide a supplemental source of electricity at Vandenberg Air Force Base (VAFB) near Lompoc, California. As part of that investigation, VAFB sought assistance from the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to provide a preliminary characterization of the potential risk to wildlife resources (mainly birds and bats) from wind turbine installations. With wind power development expanding throughout North America and Europe, concerns have surfaced over the number of bird fatalities associated with wind turbines. Guidelines developed for the wind industry by the National Wind Coordinating Committee (NWCC) recommend assessing potential impacts to birds, bats, and other potentially sensitive resources before construction. The primary purpose of an assessment is to identify potential conflicts with sensitive resources, to assist developers with identifying their permitting needs, and to develop strategies to avoid impacts or to mitigate their effects. This report provides a preliminary (Phase I) biological assessment of potential impacts to birds and bats that might result from construction and operation of the proposed wind energy facilities on VAFB.

  18. Profiling Wind and Greenhouse Gases by Infrared-laser Occultation: Algorithm and Results from Simulations in Windy Air

    NASA Astrophysics Data System (ADS)

    Plach, Andreas; Proschek, Veronika; Kirchengast, Gottfried

    2014-05-01

    We employ the Low Earth Orbit (LEO-LEO) microwave and infrared-laser occultation (LMIO) method to derive a full set of thermodynamic state variables from microwave signals and climate benchmark profiling of greenhouse gases (GHGs) and line-of-sight (l.o.s.) wind using infrared-laser signals. The focus lies on the upper troposphere/lower stratosphere region (UTLS - 5 km to 35 km). The GHG retrieval errors are generally smaller than 1% to 3% r.m.s., at a vertical resolution of about 1 km. In this study we focus on the infrared-laser part of LMIO, where we introduce a new, advanced wind retrieval algorithm to derive accurate l.o.s. wind profiles. The wind retrieval uses the reasonable assumption of the wind blowing along spherical shells (horizontal winds) and therefore the l.o.s. wind speed can be retrieved by using an Abel integral transform. A 'delta-differential transmission' principle is applied to two thoroughly selected infrared-laser signals placed at the wings of the highly symmetric C18OO absorption line (nominally ±0.004 cm-1 from the line center near 4767 cm-1) plus a related 'off-line' reference signal. The delta-differential transmission obtained by differencing these signals is clear from atmospheric broadband effects and is proportional to the wind-induced Doppler shift; it serves as the integrand of the Abel transform. The Doppler frequency shift calculated along with the wind retrieval is in turn also used in the GHG retrieval to correct the frequency of GHG-sensitive infrared-laser signals for the wind-induced Doppler shift, which enables improved GHG estimation. This step therefore provides the capability to correct potential wind-induced residual errors of the GHG retrieval in case of strong winds. We performed end-to-end simulations to test the performance of the new retrieval in windy air. The simulations used realistic atmospheric conditions (thermodynamic state variables and wind profiles) from an analysis field of the European Centre for

  19. Air-Water Gas Exchange in Wetland Water Columns Due To Wind and Thermal Convection

    NASA Astrophysics Data System (ADS)

    Poindexter, C.; Variano, E. A.

    2011-12-01

    The goal of this work is to provide a parameterization of the air-water gas transfer rate in wetlands, and do so in terms of easily measured environmental variables. This parameterization is intended to support biogeochemical modeling in wetlands by providing an interfacial flux of key importance. Our approach uses laboratory experiments describe the oxygen transfer across an air-water interface in a model wetland. The oxygen transfer is sensitive to the externally imposed wind, vegetation characteristics, and vertical thermal convection. We vary these systematically, determining the gas transfer (or "piston") velocity that describes interfacial gas flux. We measure velocity vector fields near the air-water interface using particle image velocimetry, and use these measurements to help explain the mechanisms behind the measured trends in oxygen transfer. The explanatory power of these measurements includes the relationship between plant geometry and surface divergence. We explore the potential impact of our results on wetland modeling and management, for issues such as carbon sequestration and methane emission.

  20. High-resolution daily gridded datasets of air temperature and wind speed for Europe

    NASA Astrophysics Data System (ADS)

    Brinckmann, S.; Krähenmann, S.; Bissolli, P.

    2015-08-01

    New high-resolution datasets for near surface daily air temperature (minimum, maximum and mean) and daily mean wind speed for Europe (the CORDEX domain) are provided for the period 2001-2010 for the purpose of regional model validation in the framework of DecReg, a sub-project of the German MiKlip project, which aims to develop decadal climate predictions. The main input data sources are hourly SYNOP observations, partly supplemented by station data from the ECA&D dataset (http://www.ecad.eu). These data are quality tested to eliminate erroneous data and various kinds of inhomogeneities. Grids in a resolution of 0.044° (5 km) are derived by spatial interpolation of these station data into the CORDEX area. For temperature interpolation a modified version of a regression kriging method developed by Krähenmann et al. (2011) is used. At first, predictor fields of altitude, continentality and zonal mean temperature are chosen for a regression applied to monthly station data. The residuals of the monthly regression and the deviations of the daily data from the monthly averages are interpolated using simple kriging in a second and third step. For wind speed a new method based on the concept used for temperature was developed, involving predictor fields of exposure, roughness length, coastal distance and ERA Interim reanalysis wind speed at 850 hPa. Interpolation uncertainty is estimated by means of the kriging variance and regression uncertainties. Furthermore, to assess the quality of the final daily grid data, cross validation is performed. Explained variance ranges from 70 to 90 % for monthly temperature and from 50 to 60 % for monthly wind speed. The resulting RMSE for the final daily grid data amounts to 1-2 °C and 1-1.5 m s-1 (depending on season and parameter) for daily temperature parameters and daily mean wind speed, respectively. The datasets presented in this article are published at http://dx.doi.org/10.5676/DWD_CDC/DECREG0110v1.

  1. Characterization of waviness in wind turbine blades using air coupled ultrasonics

    SciTech Connect

    Chakrapani, Sunil Kishore; Dayal, Vinay; Hsu, David K.; Barnard, Daniel J.; Gross, Andrew

    2011-06-23

    Waviness in glass fiber reinforced composite is of great interest in composite research, since it results in the loss of stiffness. Several NDE techniques have been used previously to detect waviness. This work is concerned with waves normal to the plies in a composite. Air-coupled ultrasonics was used to detect waviness in thick composites used in the manufacturing of wind turbine blades. Composite samples with different wave aspect ratios were studied. Different wavy samples were characterized, and a three step process was developed to make sure the technique is field implementable. This gives us a better understanding of the effect of waviness in thick composites, and how it affects the life and performance of the composite.

  2. Numerical modeling on air quality in an urban environment with changes of the aspect ratio and wind direction.

    PubMed

    Yassin, Mohamed F

    2013-06-01

    Due to heavy traffic emissions within an urban environment, air quality during the last decade becomes worse year by year and hazard to public health. In the present work, numerical modeling of flow and dispersion of gaseous emissions from vehicle exhaust in a street canyon were investigated under changes of the aspect ratio and wind direction. The three-dimensional flow and dispersion of gaseous pollutants were modeled using a computational fluid dynamics (CFD) model which was numerically solved using Reynolds-averaged Navier-Stokes (RANS) equations. The diffusion flow field in the atmospheric boundary layer within the street canyon was studied for different aspect ratios (W/H=1/2, 3/4, and 1) and wind directions (θ=90°, 112.5°, 135°, and 157.5°). The numerical models were validated against wind tunnel results to optimize the turbulence model. The numerical results agreed well with the wind tunnel results. The simulation demonstrated that the minimum concentration at the human respiration height within the street canyon was on the windward side for aspect ratios W/H=1/2 and 1 and wind directions θ=112.5°, 135°, and 157.5°. The pollutant concentration level decreases as the wind direction and aspect ratio increase. The wind velocity and turbulence intensity increase as the aspect ratio and wind direction increase. PMID:23192299

  3. Comparison of Tests on Air Propellers in Flight with Wind Tunnel Model Tests on Similar Forms

    NASA Technical Reports Server (NTRS)

    Durand, W F; Lesley, E P

    1926-01-01

    The purpose of this investigation was to determine the performance, characteristics, and coefficients of full-sized air propellers in flight and to compare these results with those derived from wind-tunnel tests on reduced scale models of similar geometrical form. The full-scale equipment comprised five propellers in combination with a VE-7 airplane and Wright E-4 engine. This part of the work was carried out at the Langley Memorial Aeronautical Laboratory, between May 1 and August 24, 1924, and was under the immediate charge of Mr. Lesley. The model or wind-tunnel part of the investigation was carried out at the Aerodynamic Laboratory of Stanford University and was under the immediate charge of Doctor Durand. A comparison of the curves for full-scale results with those derived from the model tests shows that while the efficiencies realized in flight are close to those derived from model tests, both thrust developed and power absorbed in flight are from 6 to 10 per cent greater than would be expected from the results of model tests.

  4. Wind tunnel experiments: cold-air pooling and atmospheric decoupling above a melting snow patch

    NASA Astrophysics Data System (ADS)

    Mott, Rebecca; Paterna, Enrico; Horender, Stefan; Crivelli, Philip; Lehning, Michael

    2016-02-01

    The longevity of perennial snowfields is not fully understood, but it is known that strong atmospheric stability and thus boundary-layer decoupling limit the amount of (sensible and latent) heat that can be transmitted from the atmosphere to the snow surface. The strong stability is typically caused by two factors, (i) the temperature difference between the (melting) snow surface and the near-surface atmosphere and (ii) cold-air pooling in topographic depressions. These factors are almost always a prerequisite for perennial snowfields to exist. For the first time, this contribution investigates the relative importance of the two factors in a controlled wind tunnel environment. Vertical profiles of sensible heat and momentum fluxes are measured using two-component hot-wire and one-component cold-wire anemometry directly over the melting snow patch. The comparison between a flat snow surface and one that has a depression shows that atmospheric decoupling is strongly increased in the case of topographic sheltering but only for low to moderate wind speeds. For those conditions, the near-surface suppression of turbulent mixing was observed to be strongest, and the ambient flow was decoupled from the surface, enhancing near-surface atmospheric stability over the single snow patch.

  5. WIND TUNNEL STUDY OF THE FLOW FIELD WITHIN AND AROUND OPEN-TOP CHAMBERS USED FOR AIR POLLUTION STUDIES

    EPA Science Inventory

    The EPA Meteorological Wind Tunnel was used to examine the flow field in and around models of open-top field plant growth chambers used to assess the effects of pollutant gases on plant growth. Baffles designed to reduce the ingress of ambient air into the chamber through the ope...

  6. Incorporation of the Wind Erosion Prediction System (WEPS) for dust into a regional air quality modeling system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion of soil is a major concern of the agricultural community as it removes the most fertile part of the soil and thus degrades soil productivity. Furthermore, suspension of eroded soil particles results in dust emissions into the atmosphere, contributing to poor air quality, reduced visibi...

  7. An evaluation of Shuttle Entry Air Data System (SEADS) flight pressures - Comparisons with wind tunnel and theoretical predictions

    NASA Technical Reports Server (NTRS)

    Henry, M. W.; Wolf, H.; Siemers, Paul M., III

    1988-01-01

    The SEADS pressure data obtained from the Shuttle flight 61-C are analyzed in conjunction with the preflight database. Based on wind tunnel data, the sensitivity of the Shuttle Orbiter stagnation region pressure distribution to angle of attack and Mach number is demonstrated. Comparisons are made between flight and wind tunnel SEADS orifice pressure distributions at several points throughout the re-entry. It is concluded that modified Newtonian theory provides a good tool for the design of a flush air data system, furnishing data for determining orifice locations and transducer sizing. Ground-based wind tunnel facilities are capable of providing the correction factors necessary for the derivation of accurate air data parameters from pressure data.

  8. Modeling the uptake of neutral organic chemicals on XAD passive air samplers under variable temperatures, external wind speeds and ambient air concentrations (PAS-SIM).

    PubMed

    Armitage, James M; Hayward, Stephen J; Wania, Frank

    2013-01-01

    The main objective of this study was to evaluate the performance and demonstrate the utility of a fugacity-based model of XAD passive air samplers (XAD-PAS) designed to simulate the uptake of neutral organic chemicals under variable temperatures, external wind speeds and ambient air concentrations. The model (PAS-SIM) simulates the transport of the chemical across the air-side boundary layer and within the sampler medium, which is segmented into a user-defined number of thin layers. Model performance was evaluated using data for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) from a field calibration study (i.e., active and XAD-PAS data) conducted in Egbert, Ontario, Canada. With some exceptions, modeled PAS uptake curves are in good agreement with the empirical PAS data. The results are highly encouraging, given the uncertainty in the active air sampler data used as input and other uncertainties related to model parametrization (e.g., sampler-air partition coefficients, the influence of wind speed on sampling rates). The study supports the further development and evaluation of the PAS-SIM model as a diagnostic (e.g., to aid interpretation of calibration studies and monitoring data) and prognostic (e.g., to inform design of future passive air sampling campaigns) tool. PMID:24175752

  9. Onshore Winds and Coastal Fog Enhance Bacterial Connections Between Water and Air In the Coastal Environment (Invited)

    NASA Astrophysics Data System (ADS)

    Dueker, M.; O'Mullan, G. D.; Juhl, A. R.; Weathers, K. C.; Uriarte, M.

    2013-12-01

    Globally, bacteria suspended in the atmosphere, or microbial aerosols, can range in concentration from 10^4 to 10^5 cells m^-3. They can be either attached to ambient aerosol particles or exist singly in the air, and can serve as ice, cloud and fog nucleators. To better understand sources for bacterial aerosols in the coastal environment, we assessed the effect of onshore wind speed on bacterial aerosol production and fallout in urban and non-urban coastal settings. We found that the fallout rate of culturable (viable) bacterial aerosols increased with onshore wind speeds. Furthermore, molecular characterization of the 16S rRNA gene diversity of bacteria from aerosols and surface waters revealed a similar species-level bacterial composition. This bacterial connection between water and air quality was strengthened at wind speeds above 4 m s^-1, with similar temporal patterns for coarse aerosol concentrations, culturable bacterial fallout rates, and presence of aquatic bacteria in near-shore aerosols. The water-air connection created by onshore winds in the coastal environment may be further modulated by coastal fog. Previous work has shown that the deposition of viable microbial aerosols increases by several orders of magnitude when fog is present in the coastal environment. Also, molecular analyses of bacteria in fog provide evidence that coastal fog enhances the viability of aerosolized marine bacteria, potentially allowing these bacteria to be transported further inland in a viable state with onshore winds. Implications for the coupling of wind-based aerosol production from surface waters with fog presence in the coastal environment include bi-directional atmospheric feedbacks between terrestrial and coastal ocean systems and the potential for water quality to affect air quality at coastal sites.

  10. The Relation Between Wind Speed and Air-Sea Temperature Difference in the Marine Atmospheric Boundary Layer off Northwest Europe

    NASA Astrophysics Data System (ADS)

    Kettle, A. J.

    2014-12-01

    Wind speed and atmospheric stability have an important role in determining the turbulence in the marine atmospheric boundary layer (MABL) as well as the surface wave field. The understanding of MABL dynamics in northwest Europe is complicated by fetch effects, the proximity of coastlines, shallow topography, and larger scale circulation patterns (e.g., cold air outbreaks). Numerical models have difficulty simulating the marine atmospheric boundary layer in coastal areas and partially enclosed seas, and this is partly due to spatial resolution problems at coastlines. In these offshore environments, the boundary layer processes are often best understood directly from time series measurements from fixed platforms or buoys, in spite of potential difficulties from platform flow distortion as well as the spatial sparseness of the data sets. This contribution presents the results of time series measurements from offshore platforms in the North Sea and Norwegian Sea in terms of a summary diagnostic - wind speed versus air-sea temperature difference (U-ΔT) - with important implications for understanding atmospheric boundary layer processes. The U-ΔT diagram was introduced in earlier surveys of data from coastal (Sletringen; O.J. Andersen and J. Løvseth, J. Wind Eng. Ind. Aerodyn., 57, 97-109, 1995) and offshore (Statfjord A; K.J. Eidsvik, Boundary-Layer Meteorol., 32, 103-132, 1985) sites in northwest Europe to summarize boundary layer conditions at a given location. Additional information from a series of measurement purpose-built offshore measurement and oil/gas production platforms from the southern North Sea to the Norwegian Sea illustrates how the wind characteristics vary spatially over large distances, highlighting the influence of cold air outbreaks, in particular. The results are important for the offshore wind industry because of the way that wind turbines accrue fatigue damage in different conditions of atmospheric stability and wind speed.

  11. Further investigations of automated surface observing system (ASOS) winds used in air quality modeling applications

    SciTech Connect

    Brower, R.P.; Jones, W.B.; Sherwell, J.

    1999-07-01

    Since 1992, a significant shift in the way standard surface meteorological data are observed and collected has occurred across the country. The National Weather Service, the Federal Aviation Administration, and the Department of Defense have been deploying the Automated Surface Observing System (ASOS) at nearly one thousand sites. Prior to ASOS, manual observation and recordation were the norm. With the advent of ASOS, an unprecedented level of meteorological data is now available; observations of standard meteorological variables are available almost real-time at more sites. However, with ASOS, meteorological data are being gathered in a fundamentally different way. New automated instruments sample, analyze, and record meteorological observations without human intervention. Many of these meteorological observations are key inputs to predictive air quality models. Reliable estimates of plume transport and dispersion require reliable and available meteorological data. The effect of the ASOS method of data collection on the dispersion modeling community is not clear. Because the hourly data now being reported at most stations across the country are being gathered in a fundamentally different way than previously, it is prudent to examine the differences between hourly meteorological observations gathered before and after ASOS. A preliminary analysis1 of pre-ASOS and ASOS data suggested that the differences in the observations could impact the data's application to air quality models. This expanded study examines more thoroughly the differences between wind data gathered before and after ASOS implementation in order to identify potential ramifications for air quality modeling. Pre-ASOS and ASOS data, from five stations in and around Maryland that represent the diversity of urbanization and topography of the region and that have a reasonably long record of ASOS observations, are examined.

  12. Laboratory study of SO2 dry deposition on limestone and marble: Effects of humidity and surface variables

    USGS Publications Warehouse

    Spiker, E. C.; Hosker, R.P., Jr.; Weintraub, V.C.; Sherwood, S.I.

    1995-01-01

    The dry deposition of gaseous air pollutants on stone and other materials is influenced by atmospheric processes and the chemical characteristics of the deposited gas species and of the specific receptor material. Previous studies have shown that relative humidity, surface moisture, and acid buffering capability of the receptor surface are very important factors. To better quantify this behavior, a special recirculating wind tunnel/environmental chamber was constructed, in which wind speed, turbulence, air temperature, relative humidity, and concentrations of several pollutants (SO2, O3, nitrogen oxides) can be held constant. An airfoil sample holder holds up to eight stone samples (3.8 cm in diameter and 1 cm thick) in nearly identical exposure conditions. SO2 deposition on limestone was found to increase exponentially with increasing relative humidity (RH). Marble behaves similarly, but with a much lower deposition rate. Trends indicate there is little deposition below 20% RH on clean limestone and below 60% RH on clean marble. This large difference is due to the limestone's greater porosity, surface roughness, and effective surface area. These results indicate surface variables generally limit SO2 deposition below about 70% RH on limestone and below at least 95% RH on marble. Aerodynamic variables generally limit deposition at higher relative humidity or when the surface is wet.The dry deposition of gaseous air pollutants on stone and other materials is influenced by atmospheric processes and the chemical characteristics of the deposited gas species and of the specific receptor material. Previous studies have shown that relative humidity, surface moisture, and acid buffering capability of the receptor surface are very important factors. To better quantify this behavior, a special recirculating wind tunnel/environmental chamber was constructed, in which wind speed, turbulence, air temperature, relative humidity, and concentrations of several pollutants (SO2, O3

  13. Ionic wind generation by a wire-cylinder-plate corona discharge in air at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Colas, Dorian F.; Ferret, Antoine; Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-11-01

    A wire-cylinder-plate electrode configuration is presented to generate ionic wind with a dc corona discharge in air at atmospheric pressure. The objective of the work is to maximize the power supplied to the flow in order to increase acceleration while avoiding breakdown. Thus, the proposed experimental setup addresses the problem of decoupling the mechanism of ion generation from that of ion acceleration. Using a wire-plate configuration as a reference, we have focused on improving the topography of the electric field to (1) separate the ionization and acceleration zones in space, and (2) guide the trajectory of charged particles as parallel to the median axis as possible. In the proposed wire-cylinder-plate setup, a dc corona discharge is generated in the space between a wire and two cylinders. The ions produced by the corona then drift past the cylinders and into a channel between two plates, where they undergo acceleration. To maximize the ionic wind it is found that the geometric configuration must be as compact as possible and that the voltage applied must be right below breakdown. Experimentally, the optimized wire-plate reference setup provides a maximum flow velocity of 8 m s-1, a flow rate per unit electrode length of 0.034 m2 s-1, and a thrust per unit electrode length of 0.24 N m-1. The wire-cylinder-plate configuration provides a maximum flow velocity of 10 m s-1, a flow rate per unit electrode length of 0.041 m2 s-1, and a thrust per unit electrode length of 0.35 N m-1. This 46% increase in thrust is obtained by increasing the electric power per unit electrode length by only 16% (from 175 to 210 W m-1), which confirms the gain in efficiency obtained with the decoupled system. In comparison with a simple wire-wire corona configuration, the wire-cylinder-plate configuration increases the ionic wind velocity by up to a factor of 3, and the thrust by an order of magnitude.

  14. [Alchemists' humid radical].

    PubMed

    Lafont, Olivier

    2007-01-01

    The term radical has been used by chemists since the beginnings and even when they still were alchemists. The term "humid radical" is present in numerous alchemists' texts. It was used to represent a kind of "humid", which was considered as different from what is nowadays called "humid", but was a sort of principle necessary for life. PMID:17575839

  15. Wind-Based Navigation of a Hot-air Balloon on Titan: A Feasibility Study

    NASA Technical Reports Server (NTRS)

    Furfaro, Roberto; Lunine, Jonathan I.; Elfes, Alberto; Reh, Kim

    2008-01-01

    Current analysis of data streamed back to Earth by the Cassini spacecraft features Titan as one of the most exciting places in the solar system. NASA centers and universities around the US, as well as the European Space Agency, are studying the possibility of sending, as part of the next mission to this giant moon of Saturn, a hot-air balloon (Montgolfier-type) for further and more in-depth exploration. The basic idea would be to design a reliable, semi-autonomous, and yet cheap Montgolfier capable of using continuous flow of waste heat from a power source to lift the balloon and sustain its altitude in the Titan environment. In this paper we study the problem of locally navigating a hot-air balloon in the nitrogen-based Titan atmosphere. The basic idea is to define a strategy (i.e. design of a suitable guidance system) that allows autonomous and semi-autonomous navigation of the balloon using the available (and partial) knowledge of the wind structure blowing on the saturnian satellite surface. Starting from first principles we determined the appropriate thermal and dynamical models describing (a) the vertical dynamics of the balloon and (b) the dynamics of the balloon moving on a vertical plane (2-D motion). Next, various non-linear fuzzy-based control strategies have been evaluated, analyzed and implemented in MATLAB to numerically simulate the capability of the system to simultaneously maintain altitude, as well as a scientifically desirable trajectory. We also looked at the ability of the balloon to perform station keeping. The results of the simulation are encouraging and show the effectiveness of such a system to cheaply and effectively perform semiautonomous exploration of Titan.

  16. High resolution system for upper air (troposphere) wind and temperature profile measurements. [meteorological radar/Jimsphere system

    NASA Technical Reports Server (NTRS)

    Camp, D. W.; Vaughan, W. W.

    1973-01-01

    The Jimsphere/Jimsonde system is described and some possible applications of the system for air-sea interface measurements are presented. As space vehicles became larger and more sophisticated, an improved method for obtaining wind profile data had to be found. To satisfy this need the FPS-16 radar/Jimsphere system was developed. The Jimsphere is an aluminized mylar spherical balloon, two meters in diameter. The balloon is under superpressure, and is tracked with a high precision radar system. The development of this detailed wind profile system was started in 1963, and the present design was established in 1964. To improve the system, a program was initiated in 1965 to obtain high resolution temperature data simultaneously with the wind profile data.

  17. Homogenization of global radiosonde humidity data

    NASA Astrophysics Data System (ADS)

    Blaschek, Michael; Haimberger, Leopold

    2016-04-01

    The global radiosonde network is an important source of upper-air measurements and is strongly connected to reanalysis efforts of the 20th century. However, measurements are strongly affected by changes in the observing system and require a homogenization before they can be considered useful in climate studies. In particular humidity measurements are known to show spurious trends and biases induced by many sources, e.g. reporting practices or freezing of the sensor. We propose to detect and correct these biases in an automated way, as has been done with temperature and winds. We detect breakpoints in dew point depression (DPD) time series by employing a standard normal homogeneity test (SNHT) on DPD-departures from ERA-Interim. In a next step, we calculate quantile departures between the latter and the earlier part near the breakpoints of the time series, going back in time. These departures adjust the earlier distribution of DPD to the latter distribution, called quantile matching, thus removing for example a non climatic shift. We employ this approach to the existing radiosonde network. In a first step to verify our approach we compare our results with ERA-Interim data and brightness temperatures of humidity-sensitive channels of microwave measuring radiometers (SSMIS) onboard DMSP F16. The results show that some of the biases can be detected and corrected in an automated way, however large biases that impact the distribution of DPD values originating from known reporting practices (e.g. 30 DPD on US stations) remain. These biases can be removed but not corrected. The comparison of brightness temperatures from satellite and radiosondes proofs to be difficult as large differences result from for example representative errors.

  18. A novel multi-beam correlation lidar for wind profiling and plume tracking for air quality applications

    NASA Astrophysics Data System (ADS)

    Prasad, N. S.

    2014-12-01

    Various types of in-situ and remote sensing techniques are being utilized for measuring air quality parameters. In this paper, the development and testing of a novel three beam multifunctional direct detection lidar for air quality applications will be discussed. Operating at 1030 nm wavelength, this lidar is a nanosecond class direct detection system with three transceivers and is capable of tracking the motion of aerosol structures using elastic backscatter. Designed with scalable and modular elements and advanced algorithms and graphical user display, this lidar is tripod mounted and measures three component (3D) winds by cross correlation of aerosol backscatter from three near-parallel beams. Besides extracting multi-component wind data, the system is designed provide various atmospheric elements including turbulence. Performance of this lidar in regard to crosswind profiling has been validated with ultrasonic anemometers under low and high wind conditions. From the field data, it shown that this lidar is capable of providing relatively high spatial resolution (<1.2 m) and line-of-sight error less than 0.1 m/s over a range of greater than 2 km. With a maximum operational range of over 15 km, this lidar was recently used to study effluents from a smokestack. The results of our plume tracking study will be presented and follow-on applications for studying air emissions due to hydraulic fracturing or fracking, will be discussed.

  19. The effects of temperature, humidity, and barometric pressure on short-sprint race times

    NASA Astrophysics Data System (ADS)

    Mureika, J. R.

    2006-04-01

    A numerical model of 100 m and 200 m world class sprinting performances is modified using standard hydrodynamic principles to include effects of air temperature, pressure, and humidity levels on aerodynamic drag. The magnitude of the effects are found to be dependent on wind speed. This implies that differing atmospheric conditions can yield slightly different corrections for the same wind-gauge reading. In the absence of wind, temperature is found to induce the largest variation in times (0.01 s per 10 degrees C increment in the 100 m), while relative humidity contributes the least (under 0.01 s for all realistic conditions for 100 m). Barometric pressure variations at a particular venue can also introduce fluctuations in performance times on the order of a 0.01 s for this race. The combination of all three variables is essentially additive, and is more important for head-wind conditions that for tail-winds. As expected, calculated corrections in the 200 m are magnified due to the longer duration of the race. The overall effects of these factors on sprint times can be considered a ``second order'' adjustment to previous methods that rely strictly on a venue's physical elevation, but can become important in extreme conditions.

  20. Why HVAC commissioning procedures do not work in humid climates

    SciTech Connect

    DuBose, G.H.; Odom, J.D. III; Fairey, P.W.

    1993-12-01

    This article discusses ways to avoid moisture damage to buildings caused by improper commissioning of HVAC systems during periods of high humidity. The topics of the article include moisture control strategies, air leakage in hot, humid climates, commissioning HVAC systems, and case studies covering central exhaust systems, building chases being used as air distribution systems, and leakage at guest room fan coil units.

  1. Synthesis, characterization, and humidity sensing of metallophtalocyanines

    NASA Astrophysics Data System (ADS)

    Chakane, Sanjay D. S.; Jain, Shilpa; Bhoraskar, S. V.

    2001-03-01

    Metallophthalocyanines synthesized for different metals such as Ni, Cr, Ag, Mg, Cu, Cd, Al, etc by chemical methods were characterized with FTIR, UV etc. Sensing of humidity and different gases such as Nox, H2, O2, CO2, N2, ammonia, alcohol vapours etc were checked with 2-probe technique with monitoring change in resistance change. These samples have excellent stability against heat, light, air, and hence it has considerable attention for environmentally stable gas sensor. The electrical property of these samples were investigated at room temperature and at normal atmospheric pressure from low to 98% relative Humidity. It was observed that these samples shows good response and recovery for humidity sensing.

  2. Improved Performance of an Air Cooled Condenser (ACC) Using SPX Wind Guide Technology at Coal-Based Thermoelectric Power Plants

    SciTech Connect

    Ken Mortensen

    2010-12-31

    This project added a new airflow enhancement technology to an existing ACC cooling process at a selected coal power plant. Airflow parameters and efficiency improvement for the main plant cooling process using the applied technology were determined and compared with the capabilities of existing systems. The project required significant planning and pre-test execution in order to reach the required Air Cooled Condenser system configuration for evaluation. A host Power Plant ACC system had to be identified, agreement finalized, and addition of the SPX ACC Wind Guide Technology completed on that site. Design of the modification, along with procurement, fabrication, instrumentation, and installation of the new airflow enhancement technology were executed. Baseline and post-modification cooling system data was collected and evaluated. The improvement of ACC thermal performance after SPX wind guide installation was clear. Testing of the improvement indicates there is a 5% improvement in heat transfer coefficient in high wind conditions and 1% improvement at low wind speed. The benefit increased with increasing wind speed. This project was completed on schedule and within budget.

  3. Static voltage distribution between turns of secondary winding of air-core spiral strip transformer and its application

    NASA Astrophysics Data System (ADS)

    Zhang, Hong-bo; Liu, Jin-liang; Cheng, Xin-bing; Zhang, Yu

    2011-09-01

    The static voltage distribution between winding turns has great impact on output characteristics and lifetime of the air-core spiral strip pulse transformer (ACSSPT). In this paper, winding inductance was calculated by electromagnetic theory, so that the static voltage distribution between turns of secondary winding of ACSSPT was analyzed conveniently. According to theoretical analysis, a voltage gradient because of the turn-to-turn capacitance was clearly noticeable across the ground turns. Simulation results of Pspice and CST EM Studio codes showed that the voltage distribution between turns of secondary winding had linear increments from the output turn to the ground turn. In experiment, the difference in increased voltage between the ground turns and the output turns of a 20-turns secondary winding is almost 50%, which is believed to be responsible for premature breakdown of the insulation, particularly between the ground turns. The experimental results demonstrated the theoretical analysis and simulation results, which had important value for stable and long lifetime ACSSPT design. A new ACSSPT with improved structure has been used successfully in intense electron beam accelerators steadily.

  4. The seasonal vertical distribution of the Saharan Air Layer and its modulation by the wind

    NASA Astrophysics Data System (ADS)

    Tsamalis, C.; Chédin, A.; Pelon, J.; Capelle, V.

    2013-11-01

    winter and 9 m deg-1 in summer. Spring and fall present similar characteristics for both mean altitude and geometrical thickness. Wind plays a major role not only for the transport of dust within the SAL but also by sculpting it. During winter, the trade winds transport SAL towards South America, while in spring and summer they bring dust-free maritime air masses mainly from the North Atlantic up to about 50° W below the SAL. The North Atlantic westerlies, with their southern border occurring between 15 and 30° N (depending on the season, the longitude and the altitude), prevent the SAL from developing further northward. In addition, their southward shift with altitude gives SAL its characteristic oval shape in the northern part. The effective dry deposition velocity of dust particles is estimated to be 0.07 cm s-1 in winter, 0.14 cm s-1 in spring, 0.2 cm s-1 in summer and 0.11 cm s-1 in fall. Finally, the African Easterly Jet (AEJ) is observed to collocate with the maximum dust load of the SAL, and this might promote the differential advection for SAL parts, especially during summer.

  5. 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 ...

  6. Transition from downward to upward air-sea momentum transfer in swell-dominated light wind condition

    NASA Astrophysics Data System (ADS)

    Smedman, Ann-Sofi; Högström, Ulf; Rutgersson, Anna

    2016-04-01

    Atmospheric and surface wave data from two oceanic experiments carried out on FLIP and ASIS platforms are analysed in order to identify swell-related effects on the momentum exchange during low wind speed conditions. The RED experiment was carried out on board an R/P Floating Instrument Platform, FLIP, anchored north east of the Hawaiian island Oahu with sonic anemometers at four levels: 5.1 m, 6.9 m, 9.9 m and 13.8 m respectively. The meteorological conditions were characterized by north- easterly trade wind and with swell present during most of the time. During swell the momentum flux was directed downwards meaning a positive contribution to the stress. The FETCH experiment was carried out in the Gulf of Lion in the north-western Mediterranean Sea. On the ASIS (air-sea interaction spar) buoy a sonic anemometer was mounted at 7 m above the mean surface level. During strong swell conditions the momentum flux was directed upwards meaning a negative contribution to the stress in this case. The downward momentum flux is shown to be a function of the orbital circulation while the upward momentum flux is a function of wave height. The dividing wind speed is found to be 3.5 m/s Conclusion: Wind speed > 3.5 m/s creates waves (ripples) and thus roughness. Combination of orbital motion and asymmetric structure of ripples lead to flow perturbation and downward transport of negative momentum. With low wind speed (no ripples but viscosity) circulations will form above the crest and the trough with opposite direction which will cause a pressure drop in the vertical direction and an upward momentum transport from the water to the air.

  7. Completion of the Edward Air Force Base Statistical Guidance Wind Tool

    NASA Technical Reports Server (NTRS)

    Dreher, Joseph G.

    2008-01-01

    The goal of this task was to develop a GUI using EAFB wind tower data similar to the KSC SLF peak wind tool that is already in operations at SMG. In 2004, MSFC personnel began work to replicate the KSC SLF tool using several wind towers at EAFB. They completed the analysis and QC of the data, but due to higher priority work did not start development of the GUI. MSFC personnel calculated wind climatologies and probabilities of 10-minute peak wind occurrence based on the 2-minute average wind speed for several EAFB wind towers. Once the data were QC'ed and analyzed the climatologies were calculated following the methodology outlined in Lambert (2003). The climatologies were calculated for each tower and month, and then were stratified by hour, direction (10" sectors), and direction (45" sectors)/hour. For all climatologies, MSFC calculated the mean, standard deviation and observation counts of the Zminute average and 10-minute peak wind speeds. MSFC personnel also calculated empirical and modeled probabilities of meeting or exceeding specific 10- minute peak wind speeds using PDFs. The empirical PDFs were asymmetrical and bounded on the left by the 2- minute average wind speed. They calculated the parametric PDFs by fitting the GEV distribution to the empirical distributions. Parametric PDFs were calculated in order to smooth and interpolate over variations in the observed values due to possible under-sampling of certain peak winds and to estimate probabilities associated with average winds outside the observed range. MSFC calculated the individual probabilities of meeting or exceeding specific 10- minute peak wind speeds by integrating the area under each curve. The probabilities assist SMG forecasters in assessing the shuttle FR for various Zminute average wind speeds. The A M ' obtained the processed EAFB data from Dr. Lee Bums of MSFC and reformatted them for input to Excel PivotTables, which allow users to display different values with point

  8. Air-sea dimethylsulfide (DMS) gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

    NASA Astrophysics Data System (ADS)

    Bell, T. G.; De Bruyn, W.; Miller, S. D.; Ward, B.; Christensen, K.; Saltzman, E. S.

    2013-11-01

    Shipboard measurements of eddy covariance dimethylsulfide (DMS) air-sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s-1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air-sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near-surface water-side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air-sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.

  9. Influence of humidity on hot-wire measurements

    NASA Astrophysics Data System (ADS)

    Durst, Franz; Noppenberger, Stefan; Still, Martin; Venzke, Holger

    1996-10-01

    When applying hot-wire anemometry to velocity measurements in air, it is standard practice to neglect the effect of humidity. In this paper the influence of the thermodynamic and transport properties of humid air on hot-wire measurements is examined on the basis of the correlations for Nusselt number proposed previously by other researchers. Experimental results at controlled levels of relative humidity between 30% and 90% at 0957-0233/7/10/021/img1, 0957-0233/7/10/021/img2 and 0957-0233/7/10/021/img3 are reproduced satisfactorily by the theoretical approaches of two of these equations. A corrective term is defined to expand formulae designed for dry air to work in a humid environment. The error in velocity by omitting the influence of humidity is estimated in terms of temperature and relative humidity.

  10. Vegetative buffers for swine odor mitigation - wind tunnel evaluation of air flow dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scale model wind tunnel experiments were completed to determine the effectiveness and feasibility of vegetative buffers to mitigate swine odor and particulate transport. Three series of wind tunnel experiments were completed. The first included four swine housing unit models and either a slurry tank...

  11. Long-distance recording of the humidity over the sea

    NASA Technical Reports Server (NTRS)

    Buklanov, V. V.; Klaptsov, V. M.

    1975-01-01

    A procedure is developed for long distance recording of humidity over the sea that uses humidity detectors of the sorption type, whose electrical properties depend on the relative humidity of the air. The moisture sensitive material of the hygristor is the organic polymer polyacrylonitryl, deposited on silver electrodes and thermally treated. In the measurements of the relative humidity from 60% to 95%, the resistance of the hygristor varies from several hundred kiloohms to a few kiloohms, and is an essentially nonlinear function of the humidity.

  12. Interpolation Correlations for Fluid Properties of Humid Air in the Temperature Range 100 °C to 200 °C

    NASA Astrophysics Data System (ADS)

    Melling, Adrian; Noppenberger, Stefan; Still, Martin; Venzke, Holger

    1997-07-01

    This paper provides simple analytical correlations for selected thermodynamic and fluid transport properties for the mixture dry air and water vapor. These correlations are derived from theory as well as from numerical fitting procedures and give expressions for density ϱ, viscosity μ, thermal conductivity k, specific heat cp, and Prandtl number Pr at a working pressure of p=1 bar and for a temperature range from 100 °C to 200 °C. The main purpose is to present a comparatively simple set of equations, as the correlations do not reflect in every case the underlying physical background. Since experimental data are scarce for the properties under investigation, it was in some cases necessary to extrapolate the available correlations to temperatures or water vapor contents where no experimental data could be found. The derived equations are compared with the pure component values for dry air and water vapor and, as far as possible, also for air-water vapor mixtures.

  13. Tool for Forecasting Cool-Season Peak Winds Across Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Roeder, William P.

    2010-01-01

    The expected peak wind speed for the day is an important element in the daily morning forecast for ground and space launch operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45th Weather Squadron (45 WS) must issue forecast advisories for KSC/CCAFS when they expect peak gusts for >= 25, >= 35, and >= 50 kt thresholds at any level from the surface to 300 ft. In Phase I of this task, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a cool-season (October - April) tool to help forecast the non-convective peak wind from the surface to 300 ft at KSC/CCAFS. During the warm season, these wind speeds are rarely exceeded except during convective winds or under the influence of tropical cyclones, for which other techniques are already in use. The tool used single and multiple linear regression equations to predict the peak wind from the morning sounding. The forecaster manually entered several observed sounding parameters into a Microsoft Excel graphical user interface (GUI), and then the tool displayed the forecast peak wind speed, average wind speed at the time of the peak wind, the timing of the peak wind and the probability the peak wind will meet or exceed 35, 50 and 60 kt. The 45 WS customers later dropped the requirement for >= 60 kt wind warnings. During Phase II of this task, the AMU expanded the period of record (POR) by six years to increase the number of observations used to create the forecast equations. A large number of possible predictors were evaluated from archived soundings, including inversion depth and strength, low-level wind shear, mixing height, temperature lapse rate and winds from the surface to 3000 ft. Each day in the POR was stratified in a number of ways, such as by low-level wind direction, synoptic weather pattern, precipitation and Bulk Richardson number. The most accurate Phase II equations were then selected for an independent verification. The Phase I and II forecast methods were

  14. Enhancing performance and uniformity of CH3NH3PbI3−xClx perovskite solar cells by air-heated-oven assisted annealing under various humidities

    PubMed Central

    Zhou, Qing; Jin, Zhiwen; Li, Hui; Wang, Jizheng

    2016-01-01

    To fabricate high-performance metal-halide perovskite solar cells, a thermal annealing process is indispensable in preparing high quality perovskite film. And usually such annealing is performed on hot plate. However hot-plate annealing could cause problems such as inhomogeneous heating (induced by non-tight contact between the sample and the plate), it is also not fit for large scale manufactory. In this paper, we conduct the annealing process in air-heated oven under various humidity environments, and compared the resulted films (CH3NH3PbI3−xClx) and devices (Al/PC61BM/CH3NH3PbI3−xClx/PEDOT:PSS/ITO/glass) with that obtained via hot-plate annealing. It is found that the air-heated-oven annealing is superior to the hot-plate annealing: the annealing time is shorter, the films are more uniform, and the devices exhibit higher power conversion efficiency and better uniformity. The highest efficiencies achieved for the oven and hot-plate annealing processes are 14.9% and 13.5%, and the corresponding standard deviations are 0.5% and 0.8%, respectively. Our work here indicates that air-heated-oven annealing could be a more reliable and more efficient way for both lab research and large-scale production. PMID:26879260

  15. Enhancing performance and uniformity of CH3NH3PbI3-xClx perovskite solar cells by air-heated-oven assisted annealing under various humidities

    NASA Astrophysics Data System (ADS)

    Zhou, Qing; Jin, Zhiwen; Li, Hui; Wang, Jizheng

    2016-02-01

    To fabricate high-performance metal-halide perovskite solar cells, a thermal annealing process is indispensable in preparing high quality perovskite film. And usually such annealing is performed on hot plate. However hot-plate annealing could cause problems such as inhomogeneous heating (induced by non-tight contact between the sample and the plate), it is also not fit for large scale manufactory. In this paper, we conduct the annealing process in air-heated oven under various humidity environments, and compared the resulted films (CH3NH3PbI3-xClx) and devices (Al/PC61BM/CH3NH3PbI3-xClx/PEDOT:PSS/ITO/glass) with that obtained via hot-plate annealing. It is found that the air-heated-oven annealing is superior to the hot-plate annealing: the annealing time is shorter, the films are more uniform, and the devices exhibit higher power conversion efficiency and better uniformity. The highest efficiencies achieved for the oven and hot-plate annealing processes are 14.9% and 13.5%, and the corresponding standard deviations are 0.5% and 0.8%, respectively. Our work here indicates that air-heated-oven annealing could be a more reliable and more efficient way for both lab research and large-scale production.

  16. Verification and implementation of microburst day potential index (MDPI) and wind INDEX (WINDEX) forecasting tools at Cape Canaveral Air Station

    NASA Technical Reports Server (NTRS)

    Wheeler, Mark

    1996-01-01

    This report details the research, development, utility, verification and transition on wet microburst forecasting and detection the Applied Meteorology Unit (AMU) did in support of ground and launch operations at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). The unforecasted wind event on 16 August 1994 of 33.5 ms-1 (65 knots) at the Shuttle Landing Facility raised the issue of wet microburst detection and forecasting. The AMU researched and analyzed the downburst wind event and determined it was a wet microburst event. A program was developed for operational use on the Meteorological Interactive Data Display System (MIDDS) weather system to analyze, compute and display Theta(epsilon) profiles, the microburst day potential index (MDPI), and wind index (WINDEX) maximum wind gust value. Key microburst nowcasting signatures using the WSR-88D data were highlighted. Verification of the data sets indicated that the MDPI has good potential in alerting the duty forecaster to the potential of wet microburst and the WINDEX values computed from the hourly surface data do have potential in showing a trend for the maximum gust potential. WINDEX should help in filling in the temporal hole between the MDPI on the last Cape Canaveral rawinsonde and the nowcasting radar data tools.

  17. Metabolic response to air temperature and wind in day-old mallards and a standard operative temperature scale

    USGS Publications Warehouse

    Bakken, G.S.; Reynolds, P.S.; Kenow, K.P.; Korschgen, C.E.; Boysen, A.F.

    1999-01-01

    Most duckling mortality occurs during the week following hatching and is often associated with cold, windy, wet weather and scattering of the brood. We estimated the thermoregulatory demands imposed by cold, windy weather on isolated 1-d-old mallard (Anas platyrhynchos) ducklings resting in cover. We measured O-2 consumption and evaporative water loss at air temperatures from 5 degrees to 25 degrees C and wind speeds of 0.1, 0.2, 0.5, and 1.0 mis. Metabolic heat production increased as wind increased or temperature decreased but was less sensitive to wind than that of either adult passerines or small mammals. Evaporative heat loss ranged from 5% to 17% of heat production. Evaporative heal loss and the ratio of evaporative heat loss to metabolic heat production was significantly lower in rest phase. These data were used to define a standard operative temperature (T-es) scale for night or heavy overcast conditions. An increase of wind speed from 0.1 to 1 mis decreased T-es by 3 degrees-5 degrees C.

  18. Hot air ablowin! 'Media-speak', social conflict, and the Australian 'decoupled' wind farm controversy.

    PubMed

    Hindmarsh, Richard

    2014-04-01

    In work in science, technology, and society social conflict around wind farms has a growing profile, not least because it draws our attention to two key interrelated themes: 'science, technology and governance' and 'socio-technological systems'. In this article on Australian wind farm development and siting, these themes are highlighted in contexts of sustainability, legitimacy, and competency for policy effectiveness. There is enduring social conflict around wind farms at the local community level, but little government understanding of this conflict or willingness to respond adequately to resolve it. This article examines the conflict through the lens of print media analysis. A key finding of the five identified is that people seeing wind farms as spoiling a sense of place is a primary cause of enduring social conflict at the local community level around wind farms, alongside significant environmental issues and inadequate community engagement; this finding also indicates a central reason for the highly problematic state of Australian wind energy transitions. In turn, by identifying this problematic situation as one of a significantly 'decoupled' and 'dysfunctional' condition of the Australian socio-technological wind farm development and siting system, I suggest remedies including those of a deliberative nature that also respond to the Habermas-Mouffe debate. These inform a socio-technical siting approach or pathway to better respect and navigate contested landscapes for enhanced renewable energy transitions at the local level. PMID:24941611

  19. Evaluation of the desiccation tolerance of blastospores of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomyces)using a lab- scale, air-drying chamber with controlled relative humidity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The stabilization of living microbial agents for use as biological control agents is often accomplished through desiccation. The drying process must be conducive to the survival of the living microbial agent during desiccation and storage. Our air-drying studies with liquid culture-produced blasto...

  20. 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.

  1. How factoring in humidity adds value

    SciTech Connect

    Berlin, G. )

    1994-09-01

    Humidity plays a major role in health, comfort, and production. This article is a brief overview of the technologies available and a detailed explanation of how to calculate humidification loads. The problems caused by dry air vary from one building to another and from one area to another. But basically, there are three major problem types: static electricity, poor moisture stability, health and comfort problems. In today's business offices, static electricity can disrupt operations and increase operating costs. In printing facilities, low humidity causes poor ink registration. Also, sheets of paper stick together and jam machines, wasting time and paper. In computer rooms and data processing areas, dry air leads to static electric discharges that cause circuit board failure, dust buildup on heads, and storage tape breakage. Moisture stability impacts industrial processes and the materials they use. In many cases, product and material deterioration is directly related to moisture fluctuations and lack of humidity control. Books, antiques, paper, wood and wood products, and fruits and vegetables are a few items that can be ruined by low or changing humidity. The health impact of low humidity shows up in dry nasal and thread membranes, dry and itchy skin, and irritated eyes. For employees, this means greater susceptibility to colds and other viral infections. The results is higher absenteeism when humidity is low, which translates into lost productivity and profits.

  2. Method for measuring temperatures and densities in hypersonic wind tunnel air flows using laser-induced O2 fluorescence

    NASA Technical Reports Server (NTRS)

    Laufer, Gabriel; Mckenzie, Robert L.; Fletcher, Douglas G.

    1990-01-01

    Laser-induced fluorescence in oxygen, in combination with Raman scattering, is shown to be an accurate means by which temperature, density, and their fluctuations owing to turbulence can be measured in air flows associated with high-speed wind tunnels. For temperatures above 60 K and densities above 0.01 amagat, the uncertainties in the temperature and density measurements can be less than 2 percent, if the signal uncertainties are dominated by photon statistical noise. The measurements are unaffected by collisional quenching and can be achieved with laser fluences for which nonlinear effects are insignificant. Temperature measurements using laser-induced fluorescence alone have been demonstrated at known densities in the range of low temperatures and densities which are expected in a hypersonic wind tunnel.

  3. A method for measuring temperatures and densities in hypersonic wind tunnel air flows using laser-induced O2 fluorescence

    NASA Technical Reports Server (NTRS)

    Laufer, Gabriel; Fletcher, Douglas G.; Mckenzie, Robert L.

    1990-01-01

    Laser-induced fluorescence in oxygen, in combination with Raman scattering, is shown to be an accurate means by which temperature, density, and their fluctuations due to turbulence can be measured in air flows associated with high-speed wind tunnels. For temperatures above 60 K and densities above 0.01 amagat, the uncertainty in the temperature and density measurements can be less than 2 and 3 percent, respectively, if the signal uncertainties are dominated by photon-statistical noise. The measurements are unaffected by collisional quenching and can be achieved with laser fluences for which nonlinear effects are insignificant. Temperature measurements using laser-induced fluorescence alone have been demonstrated at known densities in the range of low temperatures and densities which are expected in a hypersonic wind tunnel.

  4. The measured field performances of eight different mechanical and air-lift water-pumping wind-turbines

    SciTech Connect

    Kentfield, J.A.C.

    1996-12-31

    Results are presented of the specific performances of eight, different, water-pumping wind-turbines subjected to impartial tests at the Alberta Renewable Energy Test Site (ARETS), Alberta, Canada. The results presented which were derived from the test data, obtained independently of the equipment manufacturers, are expressed per unit of rotor projected area to eliminate the influence of machine size. Hub-height wind speeds and water flow rates for a common lift of 5.5 m (18 ft) constitute the essential test data. A general finding was that, to a first approximation, there were no major differences in specific performance between four units equipped with conventional reciprocating pumps two of which employed reduction gearing and two of which did not. It was found that a unit equipped with a Moyno pump performed well but three air-lift machines had, as was expected, poorer specific performances than the more conventional equipment. 10 refs., 9 figs.

  5. Modeling the effect of humidity on the threshold friction velocity of coal particles

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaochun; Chen, Weiping; Ma, Chun; Zhan, Shuifen

    2012-09-01

    Coal particles emission could cause serious air pollution in coal production region and transport region. In coal mining industry, large amounts of water are regularly spayed to coal piles to prevent dust emission from the coal particles. The mechanism behind this measure is to manage the threshold friction velocity, which is an important parameter in controlling wind erosion and dust emission. Bagnold has developed a threshold friction velocity model for soil particles. However, the Bagnold model cannot be applied directly to coal particles as coal particles are quite different from soils in physical and chemical properties. We studied and modeled threshold friction velocity of coal particles under different humidities by using a wind tunnel. Results showed that the effects of humidity on coal particles' threshold friction velocity are related to the hydrophilic effect and adhesive effect. Bagnold model can be corrected by two new parameter items which explained the two effects. The new model, agreed well with wind tunnel measurements for coal particles with different size categories. Despite the fact the new model was developed for coal particles, its physical basis may allow the model application to other wind susceptible particles.

  6. Air temperature, wind speed, and wind direction in the National Petroleum Reserve—Alaska and the Arctic National Wildlife Refuge, 1998–2011

    USGS Publications Warehouse

    Urban, Frank E.; Clow, Gary D.

    2013-01-01

    This report provides air temperature, wind speed, and wind direction data collected on Federal lands in Arctic Alaska over the period August 1998 to July 2011 by the U.S. Department of the Interior's climate monitoring array, part of the Global Terrestrial Network for Permafrost. In addition to presenting data, this report also describes monitoring, data collection, and quality control methodology. This array of 16 monitoring stations spans 68.5°N to 70.5°N and 142.5°W to 161°W, an area of roughly 150,000 square kilometers. Climate summaries are presented along with provisional quality-controlled data. Data collection is ongoing and includes several additional climate variables to be released in subsequent reports, including ground temperature and soil moisture, snow depth, rainfall, up- and downwelling shortwave radiation, and atmospheric pressure. These data were collected by the U.S. Geological Survey in close collaboration with the Bureau of Land Management and the U.S. Fish and Wildlife Service.

  7. Development of Cowling for Long-nose Air-cooled Engine in the NACA Full-scale Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Guryansky, Eugene R.; Silverstein, Abe

    1941-01-01

    An investigation of cowlings for long-nose radial engines was made on the Curtiss XP-42 fighter in the NACA full-scale wind tunnel. The unsatisfactory aerodynamic characteristics of all the cowlings with scoop inlets tested led to the development of the annular high-velocity inlet cowlings. Tests showed that ratio of cooling-air velocity at cowling inlet to stream velocity should not be less than 0.5 for this type of cowling and that critical compressibility speed can be extended to more than 500 mph at 20,000 ft altitude.

  8. Application of 50 MHz doppler radar wind profiler to launch operations at Kennedy Space Center and Cape Canaveral Air Station

    NASA Technical Reports Server (NTRS)

    Schumann, Robin S.; Taylor, Gregory E.; Smith, Steve A.; Wilfong, Timothy L.

    1994-01-01

    This paper presents a case study where a significant wind shift, not detected by jimspheres, was detected by the 50 MHz DRWP (Doppler Radar Wind Profiler) and evaluated to be acceptable prior to the launch of a Shuttle. This case study illustrates the importance of frequent upper air wind measurements for detecting significant rapidly changing features as well as for providing confidence that the features really exist and are not due to instrumentation error. Had the release of the jimsphere been timed such that it would have detected the entire wind shift, there would not have been sufficient time to release another jimsphere to confirm the existence of the feature prior to the scheduled launch. We found that using a temporal median filter on the one minute spectral estimates coupled with a constraining window about a first guess velocity effectively removes nearly all spurious signals from the velocity profile generated by NASA's 50 MHz DRWP while boosting the temporal resolution to as high as one profile every 3 minutes. The higher temporal resolution of the 50 MHz DRWP using the signal processing algorithm described in this paper ensures the detection of rapidly changing features as well as provides the confidence that the features are genuine. Further benefit is gained when the profiles generated by the DRWP are examined in relation to the profiles measured by jimspheres and/or rawinsondes. The redundancy offered by using two independent measurements can dispel or confirm any suspicion regarding instrumentation error or malfunction and wind profiles can be examined in light of their respective instruments' strengths and weaknesses.

  9. Sensitivity of honeybee hygroreceptors to slow humidity changes and temporal humidity variation detected in high resolution by mobile measurements.

    PubMed

    Tichy, Harald; Kallina, Wolfgang

    2014-01-01

    The moist cell and the dry cell on the antenna of the male honeybee were exposed to humidities slowly rising and falling at rates between -1.5%/s and +1.5%/s and at varying amplitudes in the 10 to 90% humidity range. The two cells respond to these slow humidity oscillations with oscillations in impulse frequency which depend not only on instantaneous humidity but also on the rate with which humidity changes. The impulse frequency of each cell was plotted as a function of these two parameters and regression planes were fitted to the data points of single oscillation periods. The regression slopes, which estimate sensitivity, rose with the amplitude of humidity oscillations. During large-amplitude oscillations, moist and dry cell sensitivity for instantaneous humidity and its rate of change was high. During small-amplitude oscillations, their sensitivity for both parameters was low, less exactly reflecting humidity fluctuations. Nothing is known about the spatial and temporal humidity variations a honeybee may encounter when flying through natural environments. Microclimatic parameters (absolute humidity, temperature, wind speed) were measured from an automobile traveling through different landscapes of Lower Austria. Landscape type affected extremes and mean values of humidity. Differences between peaks and troughs of humidity fluctuations were generally smaller in open grassy fields or deciduous forests than in edge habitats or forest openings. Overall, fluctuation amplitudes were small. In this part of the stimulus range, hygroreceptor sensitivity is not optimal for encoding instantaneous humidity and the rate of humidity change. It seems that honeybee's hygroreceptors are specialized for detecting large-amplitude fluctuations that are relevant for a specific behavior, namely, maintaining a sufficiently stable state of water balance. The results suggest that optimal sensitivity of both hygroreceptors is shaped not only by humidity oscillation amplitudes but also

  10. Sensitivity of Honeybee Hygroreceptors to Slow Humidity Changes and Temporal Humidity Variation Detected in High Resolution by Mobile Measurements

    PubMed Central

    Tichy, Harald; Kallina, Wolfgang

    2014-01-01

    The moist cell and the dry cell on the antenna of the male honeybee were exposed to humidities slowly rising and falling at rates between –1.5%/s and +1.5%/s and at varying amplitudes in the 10 to 90% humidity range. The two cells respond to these slow humidity oscillations with oscillations in impulse frequency which depend not only on instantaneous humidity but also on the rate with which humidity changes. The impulse frequency of each cell was plotted as a function of these two parameters and regression planes were fitted to the data points of single oscillation periods. The regression slopes, which estimate sensitivity, rose with the amplitude of humidity oscillations. During large-amplitude oscillations, moist and dry cell sensitivity for instantaneous humidity and its rate of change was high. During small-amplitude oscillations, their sensitivity for both parameters was low, less exactly reflecting humidity fluctuations. Nothing is known about the spatial and temporal humidity variations a honeybee may encounter when flying through natural environments. Microclimatic parameters (absolute humidity, temperature, wind speed) were measured from an automobile traveling through different landscapes of Lower Austria. Landscape type affected extremes and mean values of humidity. Differences between peaks and troughs of humidity fluctuations were generally smaller in open grassy fields or deciduous forests than in edge habitats or forest openings. Overall, fluctuation amplitudes were small. In this part of the stimulus range, hygroreceptor sensitivity is not optimal for encoding instantaneous humidity and the rate of humidity change. It seems that honeybee's hygroreceptors are specialized for detecting large-amplitude fluctuations that are relevant for a specific behavior, namely, maintaining a sufficiently stable state of water balance. The results suggest that optimal sensitivity of both hygroreceptors is shaped not only by humidity oscillation amplitudes but also

  11. Inter-conversion of Chromium Species During Air Sampling: Effects of O3, NO2, SO2, Particle Matrices, Temperature and Humidity

    PubMed Central

    Huang, Lihui; Fan, Zhihua (Tina); Yu, Chang Ho; Hopke, Philip K.; Lioy, Paul J.; Buckley, Brian T.; Lin, Lin; Ma, Yingjun

    2013-01-01

    The inter-conversion between Cr(VI), a pulmonary carcinogen, and Cr(III), an essential human nutrient, poses challenges to the measurement of Cr(VI) in airborne particles. Chamber and field tests were conducted to identify the factors affecting Cr(VI)-Cr(III) inter-conversion in the basic filter medium under typical sampling conditions. In the chamber tests, isotopically enriched 53Cr(VI) and 50Cr(III) were spiked on diesel particulate matter (DPM) and secondary organic aerosol (SOA) that were pre-collected on a basic MCE filter. The filter samples were then exposed to clean air or the air containing SO2 (50 and 160 ppb), 100 ppb O3, or 150 ppb NO2 for 24 hours at 16.7 LPM flow rate at designated temperature (20 and 31°C) and RH (40% and 70%) conditions. Exposure to 160 ppb SO2 had the greatest effect on 53Cr(VI) reduction, with 53Cr(VI) recovery of 31.7 ± 15.8% (DPM) and 42.0 ± 7.9% (SOA). DPM and SOA matrix induced 53Cr(VI) reduction when exposed to clean air while reactive oxygen species in SOA could promote 50Cr(III) oxidation. Deliquescence when RH increased from 40% to 70% led to conversion of Cr(III) in SOA, whereas oxidized organics in DPM and SOA enhanced hygroscopicity and thus facilitated Cr(VI) reduction. Field tests showed seasonal variation of Cr(VI)-Cr(III) inter-conversion during sampling. Correction of the inter-conversion using USEPA method 6800 is recommended to improve accuracy of ambient Cr(VI) measurements. PMID:23550818

  12. Academics explore humidity's benefits.

    PubMed

    Mortimer, Dave

    2008-11-01

    The effects of humidification on hospital superbugs are being explored by some of the UK's top academics, in what Dave Mortimer, national sales manager for Vapac Humidity Control, explains are the UK's first such studies. PMID:19044148

  13. Humidity without Mystification

    ERIC Educational Resources Information Center

    Staver, Allen E.

    1977-01-01

    Demonstrates how a simple graph can be effectively used in teaching the concept, measurement, and use of humidity. Science activities for upper elementary, secondary, and higher education students are suggested and definitions of terms are presented. (Author/DB)

  14. Heat or humidity, which triggers tree phenology?

    NASA Astrophysics Data System (ADS)

    Laube, Julia; Sparks, Tim H.; Estrella, Nicole; Menzel, Annette

    2014-05-01

    An overwhelming number of studies confirm that temperature is the main driver for phenological events such as leafing, flowering or fruit ripening, which was first discovered by Réaumur in 1735. Since then, several additional factors which influence onset dates have been identified, such as length of the chilling period, photoperiod, temperature of the previous autumn, nutrient availability, precipitation, sunshine and genetics (local adaptations). Those are supposed to capture some of the remaining, unexplained variance. But our ability to predict onset dates remains imprecise, and our understanding of how plants sense temperature is vague. From a climate chamber experiment on cuttings of 9 tree species we present evidence that air humidity is an important, but previously overlooked, factor influencing the spring phenology of trees. The date of median leaf unfolding was 7 days earlier at 90% relative humidity compared to 40% relative humidity. A second experiment with cuttings shows that water uptake by above-ground tissue might be involved in the phenological development of trees. A third climate chamber experiment suggests that winter dormancy and chilling might be linked to dehydration processes. Analysis of climate data from several meteorological stations across Germany proves that the increase in air humidity after winter is a reliable signal of spring, i.e. less variable or susceptible to reversal compared to temperature. Finally, an analysis of long-term phenology data reveals that absolute air humidity can even be used as a reliable predictor of leafing dates. Current experimental work tries to elucidate the involved foliar uptake processes by using deuterium oxide marked water and Raman spectroscopy. We propose a new framework, wherein plants' chilling requirements and frost tolerance might be attributed to desiccation processes, while spring development is linked to re-humidification of plant tissue. The influence of air humidity on the spring

  15. Aeorodynamic characteristics of an air-exchanger system for the 40- by 80-foot wind tunnel at Ames Research Center

    NASA Technical Reports Server (NTRS)

    Rossow, V. J.; Schmidt, G. I.; Meyn, L. A.; Ortner, K. R.; Holmes, R. E.

    1986-01-01

    A 1/50-scale model of the 40- by 80-Foot Wind Tunnel at Ames Research Center was used to study various air-exchange configurations. System components were tested throughout a range of parameters, and approximate analytical relationships were derived to explain the observed characteristics. It is found that the efficiency of the air exchanger could be increased (1) by adding a shaped wall to smoothly turn the incoming air downstream, (2) by changing to a contoured door at the inlet to control the flow rate, and (3) by increasing the size of the exhaust opening. The static pressures inside the circuit then remain within the design limits at the higher tunnel speeds if the air-exchange rate is about 5% or more. Since the model is much smaller than the full-scale facility, it is not possible to completely duplicate the tunnel, and it will be necessary to measure such characteristics as flow rate and tunnel pressures during implementation of the remodeled facility. The aerodynamic loads estimated for the inlet door and for nearby walls are also presented.

  16. Gas exchange in wetlands with emergent vegetation: The effects of wind and thermal convection at the air-water interface

    NASA Astrophysics Data System (ADS)

    Poindexter, Cristina M.; Variano, Evan A.

    2013-07-01

    Methane, carbon dioxide, and oxygen are exchanged between wetlands and the atmosphere through multiple pathways. One of these pathways, the hydrodynamic transport of dissolved gas through the surface water, is often underestimated in importance. We constructed a model wetland in the laboratory with artificial emergent plants to investigate the mechanisms and magnitude of this transport. We measured gas transfer velocities, which characterize the near-surface stirring driving air-water gas transfer, while varying two stirring processes important to gas exchange in other aquatic environments: wind and thermal convection. To isolate the effects of thermal convection, we identified a semiempirical model for the gas transfer velocity as a function of surface heat loss. The laboratory results indicate that thermal convection will be the dominant mechanism of air-water gas exchange in marshes with emergent vegetation. Thermal convection yielded peak gas transfer velocities of 1 cm h-1. Because of the sheltering of the water surface by emergent vegetation, gas transfer velocities for wind-driven stirring alone are likely to exceed this value only in extreme cases.

  17. Pollution by Urticaceae pollen-influence of selected air pollutants and meteorological parameters.

    PubMed

    Sabo, Nataša Čamprag; Kiš, Tibor; Janaćković, Peđa; Đorđević, Dragana; Popović, Aleksandar

    2016-05-01

    The goal of this study was to analyze the influence of pollutants (concentrations of NO2, SO2, and soot in the air) and meteorological parameters (air temperature, humidity, wind speed, air pressure, cloud index) on Urticaceae pollen type emission measured in the region of Subotica, Serbia. The concentrations of the air pollutants, Urticaceae pollen, and meteorological parameters were measured over a 5-year period (2009-2013), followed by a statistical analysis of the values obtained. For most of the years examined, the concentration of NO2 correlates significantly with the concentration of Urticaceae pollen type. It was also established that air temperature, humidity, wind speed, atmospheric pressure, and cloud index have an influence on Urticaceae pollen type emission, while SO2 and soot do not contribute. PMID:26865493

  18. A Comparison of Propeller and Centrifugal Fans for Circulating the Air in a Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Weick, Fred E

    1928-01-01

    The tests described in this paper afford a direct comparison of the efficiency and smoothness of flow obtained with propeller fan and multiblade centrifugal fan drives in the same wind tunnel. The propeller fan was found to be superior to the centrifugal fan in that the efficiency was about twice as great, and the flow much smoother.

  19. Effect of relative humidity on fungal colonization of fiberglass insulation.

    PubMed Central

    Ezeonu, I M; Noble, J A; Simmons, R B; Price, D L; Crow, S A; Ahearn, D G

    1994-01-01

    Fiberglass duct liners and fiberglass duct boards from eight buildings whose occupants complained of unacceptable or moldy odors in the air were found to be heavily colonized by fungi, particularly by Aspergillus versicolor. Unused fiberglass was found to be susceptible to fungal colonization in environmental chambers dependent upon relative humidity. No colonization was observed at relative humidities below 50%. Images PMID:8031101

  20. Temperature and humidity control of simulated human breath

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    Subsystem was developed for breathing metabolic simulator which adjusts temperature and humidity of air to levels of human exhaled breath. Temperature-humidity subsystem is described, consisting of aluminum enclosure with 400 watt heat sheet glued to bottom, vertical separators, inlet connection, and check valve.

  1. 40 CFR 86.344-79 - Humidity calculations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Humidity calculations. 86.344-79 Section 86.344-79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Humidity calculations. (a) The following abbreviations (and units) are used in this section:...

  2. Breaking waves and near-surface sea spray aerosol dependence on changing winds: Wave breaking efficiency and bubble-related air-sea interaction processes

    NASA Astrophysics Data System (ADS)

    Hwang, P. A.; Savelyev, I. B.; Anguelova, M. D.

    2016-05-01

    Simultaneous measurements of sea spray aerosol (SSA), wind, wave, and microwave brightness temperature are obtained in the open ocean on-board Floating Instrument Platform (FLIP). These data are analysed to clarify the ocean surface processes important to SSA production. Parameters are formulated to represent surface processes with characteristic length scales spanning a broad range. The investigation reveals distinct differences of the SSA properties in rising winds and falling winds, with higher SSA volume in falling winds. Also, in closely related measurements of whitecap coverage, higher whitecap fraction as a function of wind speed is found in falling winds than in rising winds or in older seas than in younger seas. Similar trend is found in the short scale roughness reflected in the microwave brightness temperature data. In the research of length and velocity scales of breaking waves, it has been observed that the length scale of wave breaking is shorter in mixed seas than in wind seas. For example, source function analysis of short surface waves shows that the characteristic length scale of the dissipation function shifts toward higher wavenumber (shorter wavelength) in mixed seas than in wind seas. Similarly, results from feature tracking or Doppler analysis of microwave radar sea spikes, which are closely associated with breaking waves, show that the magnitude of the average breaking wave velocity is smaller in mixed seas than in wind seas. Furthermore, breaking waves are observed to possess geometric similarity. Applying the results of breaking wave analyses to the SSA and whitecap observations described above, it is suggestive that larger air cavities resulting from the longer breakers are entrained in rising high winds. The larger air cavities escape rapidly due to buoyancy before they can be fully broken down into small bubbles for the subsequent SSA production or whitecap manifestation. In contrast, in falling winds (with mixed seas more likely), the

  3. Statistical Short-Range Guidance for Peak Wind Forecasts on Kennedy Space Center/Cape Canaveral Air Force Station, Phase III

    NASA Technical Reports Server (NTRS)

    Crawford, Winifred

    2010-01-01

    This final report describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The peak winds are an important forecast element for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a short-range peak-wind forecast tool to assist in forecasting LCC violations.The tool includes climatologies of the 5-minute mean and peak winds by month, hour, and direction, and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  4. 40 CFR 92.108 - Intake and cooling air measurements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... practice J244 (incorporated by reference at § 92.5) are allowed. (b) Humidity and temperature measurements. (1) Air that has had its absolute humidity altered is considered humidity-conditioned air. For this type of intake air supply, the humidity measurements must be made within the intake air supply...

  5. 40 CFR 92.108 - Intake and cooling air measurements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... recommended practice J244 (incorporated by reference at § 92.5) are allowed. (b) Humidity and temperature measurements. (1) Air that has had its absolute humidity altered is considered humidity-conditioned air. For this type of intake air supply, the humidity measurements must be made within the intake air...

  6. 40 CFR 92.108 - Intake and cooling air measurements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... recommended practice J244 (incorporated by reference at § 92.5) are allowed. (b) Humidity and temperature measurements. (1) Air that has had its absolute humidity altered is considered humidity-conditioned air. For this type of intake air supply, the humidity measurements must be made within the intake air...

  7. A Full-Envelope Air Data Calibration and Three-Dimensional Wind Estimation Method Using Global Output-Error Optimization and Flight-Test Techniques

    NASA Technical Reports Server (NTRS)

    Taylor, Brian R.

    2012-01-01

    A novel, efficient air data calibration method is proposed for aircraft with limited envelopes. This method uses output-error optimization on three-dimensional inertial velocities to estimate calibration and wind parameters. Calibration parameters are based on assumed calibration models for static pressure, angle of attack, and flank angle. Estimated wind parameters are the north, east, and down components. The only assumptions needed for this method are that the inertial velocities and Euler angles are accurate, the calibration models are correct, and that the steady-state component of wind is constant throughout the maneuver. A two-minute maneuver was designed to excite the aircraft over the range of air data calibration parameters and de-correlate the angle-of-attack bias from the vertical component of wind. Simulation of the X-48B (The Boeing Company, Chicago, Illinois) aircraft was used to validate the method, ultimately using data derived from wind-tunnel testing to simulate the un-calibrated air data measurements. Results from the simulation were accurate and robust to turbulence levels comparable to those observed in flight. Future experiments are planned to evaluate the proposed air data calibration in a flight environment.

  8. Wind-Tunnel Investigation of Air Inlet and Outlet Openings for Aircraft, Special Report

    NASA Technical Reports Server (NTRS)

    Rogallo, Francis M.; Gauvain, William E.

    1938-01-01

    An investigation was made in the NACA 5-foot vertical wind tunnel of a large variety of duct inlets and outlets to obtain information relative to their design for the cooling or the ventilation systems on aircraft. Most of the tests were of openings in a flat plate but, in order to determine the best locations and the effects of interference, a few tests were made of openings in an airfoil. The best inlet location for a system not including a blower was found to be at the forward stagnation point; for one including a blower, the best location was found to be in the region of lowest total head, probably in the boundary layer near the trailing edge. Design recommendations are given, and it is shown that correct design demands a knowledge of the external flow and of the internal requirements in addition to that obtained from the results of the wind tunnel tests.

  9. A 20-KW Wind Energy Conversion System (WECS) at the Marine Corps Air Station, Kaneohe, Hawaii

    NASA Astrophysics Data System (ADS)

    Pal, D.

    1983-01-01

    The wind turbine generator chosen for the evaluation was a horizontal-axis-propeller-downwind rotor driving a three-phase, self-excited alternator through a step-up gear box. The alternator is fed into the base power distribution system through a three-phase, line-communtated-synchronous inverter using SCRs. The site has moderate wind conditions with an annual average windspeed of 12 to 14 mph, and the WECS turbine has a relatively high (29 mph) rated windspeed. The 20-kW WECS systems was primarily designed to obtain operating experience with, and maintenance information on, a 20-kW-sized WECS. This report describes in detail the experience gained and lessons learned during the field evaluation.

  10. United States Air Force Academy (USAFA) Vertical Axis Wind Turbine. Final report May 77-Sep 80

    SciTech Connect

    Kullgren, T.E.; Wiedemeier, D.W.

    1980-09-01

    This report describes the design, fabrication, installation and testing of a small variable-speed vertical axis wind turbine (VAWT). This VAWT is unique in its installation using hand tools only; unconventional and simple support system; and variable speed operation under microprocessor control. Initial testing confirmed that the turbine can be controlled by commanded alternator field modulation. Further studies will be directed toward determination of an optimum control algorithm.

  11. Scheduling whole-air samples above the Trade Wind Inversion from SUAS using real-time sensors

    NASA Astrophysics Data System (ADS)

    Freer, J. E.; Greatwood, C.; Thomas, R.; Richardson, T.; Brownlow, R.; Lowry, D.; MacKenzie, A. R.; Nisbet, E. G.

    2015-12-01

    Small Unmanned Air Systems (SUAS) are increasingly being used in science applications for a range of applications. Here we explore their use to schedule the sampling of air masses up to 2.5km above ground using computer controlled bespoked Octocopter platforms. Whole-air sampling is targeted above, within and below the Trade Wind Inversion (TWI). On-board sensors profiled the TWI characteristics in real time on ascent and, hence, guided the altitudes at which samples were taken on descent. The science driver for this research is investigation of the Southern Methane Anomaly and, more broadly, the hemispheric-scale transport of long-lived atmospheric tracers in the remote troposphere. Here we focus on the practical application of SUAS for this purpose. Highlighting the need for mission planning, computer control, onboard sensors and logistics in deploying such technologies for out of line-of-sight applications. We show how such a platform can be deployed successfully, resulting in some 60 sampling flights within a 10 day period. Challenges remain regarding the deployment of such platforms routinely and cost-effectively, particularly regarding training and support. We present some initial results from the methane sampling and its implication for exploring and understanding the Southern Methane Anomaly.

  12. Interactions Between the Nighttime Valley-Wind System and a Developing Cold-Air Pool

    NASA Astrophysics Data System (ADS)

    Arduini, Gabriele; Staquet, Chantal; Chemel, Charles

    2016-06-01

    The Weather Research and Forecast numerical model is used to characterize the influence of a thermally-driven down-valley flow on a developing cold-air pool in an idealized alpine valley decoupled from the atmosphere above. Results for a three-dimensional (3D) valley, which allows for the formation of a down-valley flow, and for a two-dimensional (2D) valley, where the formation of a down-valley flow is inhibited, are analyzed and compared. A key result is that advection leads to a net cooling in the 2D valley and to a warming in the 3D valley, once the down-valley flow is fully developed. This difference stems from the suppression of the slope-flow induced upward motions over the valley centre in the 3D valley. As a result, the downslope flows develop a cross-valley circulation within the cold-air pool, the growth of the cold-air pool is reduced and the valley atmosphere is generally warmer than in the 2D valley. A quasi-steady state is reached for which the divergence of the down-valley flow along the valley is balanced by the convergence of the downslope flows at the top of the cold-air pool, with no net contribution of subsiding motions far from the slope layer. More precisely, the inflow of air at the top of the cold-air pool is found to be driven by an interplay between the return flow from the plain region and subsidence over the plateaux. Finally, the mechanisms that control the structure of the cold-air pool and its evolution are found to be independent of the valley length as soon as the quasi-steady state is reached and the down-valley flow is fully developed.

  13. Modulation of the Wind Speed Response of Marine Stratocumulus Clouds

    NASA Astrophysics Data System (ADS)

    Kazil, J.; Feingold, G.

    2014-12-01

    We explore a possible feedback mechanism of marine boundary layer clouds in response to expected 21st century changes in large scale wind speed. The mechanism proceeds via the effect of wind speed on the surface fluxes of sensible and latent heat, horizontal momentum (shear), and sea spray aerosol, and associated changes to cloud properties. An increase in wind speed produces, e.g., a higher latent heat flux from the surface, which causes stronger entrainment of free tropospheric air, and an adjustment in cloud properties. We have investigated how free tropospheric humidity and the evolution of the boundary layer modify the response of marine stratocumulus clouds to changes in wind speed. Results of cloud-system-resolving simulations are presented. The response of cloud properties and of radiative forcing to changes in surface wind speed is quantified under different free tropospheric conditions (dry vs. moist) and different boundary layer states (growing vs. steady state).

  14. Optical humidity sensor

    DOEpatents

    Tarvin, J.A.

    1987-02-10

    An optical dielectric humidity sensor is disclosed which includes a dielectric mirror having multiple alternating layers of two porous water-adsorbent dielectric materials with differing indices of refraction carried by a translucent substrate. A narrow-band polarized light source is positioned to direct light energy onto the mirror, and detectors are positioned to receive light energy transmitted through and reflected by the mirror. A ratiometer indicates humidity in the atmosphere which surrounds the dielectric mirror as a function of a ratio of light energies incident on the detectors. 2 figs.

  15. Optical humidity sensor

    DOEpatents

    Tarvin, Jeffrey A.

    1987-01-01

    An optical dielectric humidity sensor which includes a dielectric mirror having multiple alternating layers of two porous water-adsorbent dielectric materials with differing indices of refraction carried by a translucent substrate. A narrow-band polarized light source is positioned to direct light energy onto the mirror, and detectors are positioned to receive light energy transmitted through and reflected by the mirror. A ratiometer indicates humidity in the atmosphere which surrounds the dielectric mirror as a function of a ratio of light energies incident on the detectors.

  16. 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

  17. A 400 year reconstruction of July relative air humidity for the region Vienna (eastern Austria) based on carbon and oxygen stable isotope ratios in tree-ring latewood cellulose of oaks

    NASA Astrophysics Data System (ADS)

    Haupt, M.; Boettger, T.; Weigl, M.; Grabner, M.

    2009-04-01

    Stable isotope chronologies and correlation to climate. We present the stable isotope chronologies of carbon (^13Clw) and oxygen (^18Olw) for the period from 1600 to 2003 respectively of non-exchangeable hydrogen (^2Hlw) for the last century constructed base upon tree-ring latewood cellulose from oaks (Quercus petraea Matt. Liebl.) grown in the region Vienna (Austria). The stable isotope ratios correspond mainly to the summer climate conditions. For the calibration period (1900-2003) we found high significant correlations (p < 0.001) between ^13Clw and relative air humidity (RH) of July (-0.66), between ^18Olw and RHV I-V II (-0.61) and between ^2Hlw and RHV I-V III(-0.56). In the case of temperatures high significant correlations between the growing season temperature and ^13Clw (0.55), between the annual mean temperatures and ^18Olw ratios (0.45) and between summer mean temperatures (June to August) and ^2Hlw values (0.49) were estimated. Modeling. Various univariate and multivariate linear regressions models were proved for the reconstruction of summer relative air humidity and temperature. We found that establishing of robust models had several uncertainties: - using common linear transfer functions which oversimplify the complexity of relations; - using of pooled material and neglecting of different reactions from individual trees to climate; - high-order autocorrelations in the isotope time series; - climatic trends in the investigated region which are different in the first and in the second half of 20th century; - temporal instability of climate signals in the isotope ratios of tree ring cellulose. In the case of temperature no valid model could be estimated caused by temporal instabilities of signal strength. For relative air humidity two bivariate models RHV II = (-4.3 ± 0.7) * ^13Clw + (-2.8 ± 0.5) * ^18Olw + 44 [1] and RHV II = (-4.7 ± 0.7) * ^13Clw + (-0.35 ± 0.07) * ^2Hlw - 68 [2] were found as verifiable and applicable to reconstruct RHV II

  18. A 400 year reconstruction of July relative air humidity for the region Vienna (eastern Austria) based on carbon and oxygen stable isotope ratios in tree-ring latewood cellulose of oaks

    NASA Astrophysics Data System (ADS)

    Haupt, M.; Boettger, T.; Weigl, M.; Grabner, M.

    2009-04-01

    Stable isotope chronologies and correlation to climate. We present the stable isotope chronologies of carbon (^13Clw) and oxygen (^18Olw) for the period from 1600 to 2003 respectively of non-exchangeable hydrogen (^2Hlw) for the last century constructed base upon tree-ring latewood cellulose from oaks (Quercus petraea Matt. Liebl.) grown in the region Vienna (Austria). The stable isotope ratios correspond mainly to the summer climate conditions. For the calibration period (1900-2003) we found high significant correlations (p < 0.001) between ^13Clw and relative air humidity (RH) of July (-0.66), between ^18Olw and RHV I-V II (-0.61) and between ^2Hlw and RHV I-V III(-0.56). In the case of temperatures high significant correlations between the growing season temperature and ^13Clw (0.55), between the annual mean temperatures and ^18Olw ratios (0.45) and between summer mean temperatures (June to August) and ^2Hlw values (0.49) were estimated. Modeling. Various univariate and multivariate linear regressions models were proved for the reconstruction of summer relative air humidity and temperature. We found that establishing of robust models had several uncertainties: - using common linear transfer functions which oversimplify the complexity of relations; - using of pooled material and neglecting of different reactions from individual trees to climate; - high-order autocorrelations in the isotope time series; - climatic trends in the investigated region which are different in the first and in the second half of 20th century; - temporal instability of climate signals in the isotope ratios of tree ring cellulose. In the case of temperature no valid model could be estimated caused by temporal instabilities of signal strength. For relative air humidity two bivariate models RHV II = (-4.3 ± 0.7) * ^13Clw + (-2.8 ± 0.5) * ^18Olw + 44 [1] and RHV II = (-4.7 ± 0.7) * ^13Clw + (-0.35 ± 0.07) * ^2Hlw - 68 [2] were found as verifiable and applicable to reconstruct RHV II

  19. Considerations on the effect of wind-tunnel walls on oscillating air forces for two-dimensional subsonic compressible flow

    NASA Technical Reports Server (NTRS)

    Runyan, Harry L; Watkins, Charles E

    1953-01-01

    This report treats the effect of wind-tunnel walls on the oscillating two-dimensional air forces in a compressible medium. The walls are simulated by the usual method of placing images at appropriate distances above and below the wing. An important result shown is that, for certain conditions of wing frequency, tunnel height, and Mach number, the tunnel and wing may form a resonant system so that the forces on the wing are greatly changed from the condition of no tunnel walls. It is pointed out that similar conditions exist for three-dimensional flow in circular and rectangular tunnels and apparently, within certain Mach number ranges, in tunnels of nonuniform cross section or even in open tunnels or jets.

  20. Influence of current velocity and wind speed on air-water gas exchange in a mangrove estuary

    NASA Astrophysics Data System (ADS)

    Ho, David T.; Coffineau, Nathalie; Hickman, Benjamin; Chow, Nicholas; Koffman, Tobias; Schlosser, Peter

    2016-04-01

    Knowledge of air-water gas transfer velocities and water residence times is necessary to study the fate of mangrove derived carbon exported into surrounding estuaries and ultimately to determine carbon balances in mangrove ecosystems. For the first time, the 3He/SF6 dual tracer technique, which has been proven to be a powerful tool to determine gas transfer velocities in the ocean, is applied to Shark River, an estuary situated in the largest contiguous mangrove forest in North America. The mean gas transfer velocity was 3.3 ± 0.2 cm h-1 during the experiment, with a water residence time of 16.5 ± 2.0 days. We propose a gas exchange parameterization that takes into account the major sources of turbulence in the estuary (i.e., bottom generated shear and wind stress).

  1. Silver Doped Titanium Dioxide Humidity Sensor

    NASA Astrophysics Data System (ADS)

    Hooshiar Zare, Ali; Mohammadi, Somayye

    2011-02-01

    The effect of silver doping on the sensitivity, dynamic range and the response time of a titanium dioxide-based resistive humidity sensor is studied. Sample pallets were prepared by sintering the dry pressed samples at 900°C in air. Silver was added to the ceramic raw material in the form of AgNO3 which was decomposed during the sintering process. Large area silver electrodes were deposited on the sintered disks by paste printing. The resistance and the response time of the various pallets containing different additive levels were measured at relative humidity range of 4-100%. Silver doping, substantially increased the sensitivity to the ambient humidity. Moreover, it resulted in faster responses; the response time of the silver added pallets were about four times shorter than the pure ones.

  2. All-Optical Graphene Oxide Humidity Sensors

    PubMed Central

    Lim, Weng Hong; Yap, Yuen Kiat; Chong, Wu Yi; Ahmad, Harith

    2014-01-01

    The optical characteristics of graphene oxide (GO) were explored to design and fabricate a GO-based optical humidity sensor. GO film was coated onto a SU8 polymer channel waveguide using the drop-casting technique. The proposed sensor shows a high TE-mode absorption at 1550 nm. Due to the dependence of the dielectric properties of the GO film on water content, this high TE-mode absorption decreases when the ambient relative humidity increases. The proposed sensor shows a rapid response (<1 s) to periodically interrupted humid air flow. The transmission of the proposed sensor shows a linear response of 0.553 dB/% RH in the range of 60% to 100% RH. PMID:25526358

  3. Lanthanide-halide based humidity indicators

    DOEpatents

    Beitz, James V.; Williams, Clayton W.

    2008-01-01

    The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.

  4. Hands-on Humidity.

    ERIC Educational Resources Information Center

    Pankiewicz, Philip R.

    1992-01-01

    Presents five hands-on activities that allow students to detect, measure, reduce, and eliminate moisture. Students make a humidity detector and a hygrometer, examine the effects of moisture on different substances, calculate the percent of water in a given food, and examine the absorption potential of different desiccants. (MDH)

  5. Desiccant humidity control system

    NASA Technical Reports Server (NTRS)

    Amazeen, J. (Editor)

    1973-01-01

    A regenerable sorbent system was investigated for controlling the humidity and carbon dioxide concentration of the space shuttle cabin atmosphere. The sorbents considered for water and carbon dioxide removal were silica gel and molecular sieves. Bed optimization and preliminary system design are discussed along with system optimization studies and weight penalites.

  6. Dependence of urban air pollutants on meteorology.

    PubMed

    Elminir, Hamdy K

    2005-11-01

    Dependence of air pollutants on meteorology is presented with the aim of understanding the governing processes pollutants phase interaction. Intensive measurements of particulate matter (PM10) and gaseous materials (e.g., CO, NO2, SO2, and O3) are carried out regularly in 2002 at 14 measurement sites distributed over the whole territory of Great Cairo by the Egyptian Environmental Affairs Agency to assess the characteristics of air pollutants. The discussions in this work are based upon measurements performed at Abbassiya site as a case study. The nature of the contributing sources has been investigated and some attempts have been made to indicate the role played by neighboring regions in determining the air quality at the site mentioned. The results hint that, wind direction was found to have an influence not only on pollutant concentrations but also on the correlation between pollutants. As expected, the pollutants associated with traffic were at highest ambient concentration levels when wind speed was low. At higher wind speeds, dust and sand from the surrounding desert was entrained by the wind, thus contributing to ambient particulate matter levels. We also found that, the highest average concentration for NO2 and O3 occurred at humidityhumidity above 80%. PMID:16227082

  7. Data Center Economizer Contamination and Humidity Study

    SciTech Connect

    Shehabi, Arman; Tschudi, William; Gadgil, Ashok

    2007-03-06

    Data centers require continuous air conditioning to address high internal heat loads (heat release from equipment) and maintain indoor temperatures within recommended operating levels for computers. Air economizer cycles, which bring in large amounts of outside air to cool internal loads when weather conditions are favorable, could save cooling energy. There is reluctance from many data center owners to use this common cooling technique, however, due to fear of introducing pollutants and potential loss of humidity control. Concerns about equipment failure from airborne pollutants lead to specifying as little outside air as permissible for human occupants. To investigate contamination levels, particle monitoring was conducted at 8 data centers in Northern California. Particle counters were placed at 3 to 4 different locations within and outside of each data center evaluated in this study. Humidity was also monitored at many of the sites to determine how economizers affect humidity control. Results from this study indicate that economizers do increase the outdoor concentration in data centers, but this concentration, when averaged annually, is still below current particle concentration limits. Study results are summarized below: (1) The average particle concentrations measured at each location, both outside and at the servers, are shown in Table 1. Measurements show low particle concentrations at all data centers without economizers, regardless of outdoor particle concentrations. Particle concentrations were typically an order of magnitude below both outside particle concentrations and recently published ASHRAE standards. (2) Economizer use caused sharp increases in particle concentrations when the economizer vents were open. The particle concentration in the data centers, however, quickly dropped back to pre-economizer levels when the vents closed. Since economizers only allow outside air part of the time, the annual average concentrations still met the ASHRAE

  8. Wind-Tunnel Investigation of Air Inlet and Outlet Openings on a Streamline Body

    NASA Technical Reports Server (NTRS)

    Becker, John V

    1951-01-01

    In connection with the general problem of providing air flow to an aircraft power plant located within a fuselage, an investigation was conducted in the Langley 8-foot high-speed tunnel to determine the effect on external drag and pressure distribution of air inlet openings located at the nose of a streamline body. Air outlet openings located at the tail and at the 21-percent and 63-percent stations of the body were also investigated. Boundary layer transition measurements were made and correlated with the force and the pressure data. Individual openings were investigated with the aid of a blower and then practicable combinations of inlet and outlet openings were tested. Various modifications to the internal duct shape near the inlet opening and the aerodynamic effects of a simulated gun in the duct were also studied. The results of the tests suggested that outlet openings should be designed so that the static pressure of the internal flow at the outlet would be the same as the static pressure of the external flow in the vicinity of the opening.

  9. Measure Guideline: Supplemental Dehumidification in Warm-Humid Climates

    SciTech Connect

    Rudd, Armin

    2014-10-01

    This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. Cooling loads are typically high and cooling equipment runs a lot to cool the air in older homes in warm-humid climates. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisture being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and winter days. In warm-humid climates, those long-off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.

  10. Measure Guideline: Supplemental Dehumidification in Warm-Humid Climates

    SciTech Connect

    Rudd, A.

    2014-10-01

    This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. In older homes in warm-humid climates, cooling loads are typically high and cooling equipment runs a lot to cool the air. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisture being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and some winter days. In warm-humid climates, those long off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and avoids adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.

  11. Wind tunnel evaluation of air-foil performance using simulated ice shapes

    NASA Technical Reports Server (NTRS)

    Bragg, M. B.; Zaguli, R. J.; Gregorek, G. M.

    1982-01-01

    A two-phase wind tunnel test was conducted in the 6 by 9 foot Icing Research Tunnel (IRT) at NASA Lewis Research Center to evaluate the effect of ice on the performance of a full scale general aviation wing. In the first IRT tests, rime and glaze shapes were carefully documented as functions of angle of attack and free stream conditions. Next, simulated ice shapes were constructed for two rime and two glaze shapes and used in the second IRT tunnel entry. The ice shapes and the clean airfoil were tapped to obtain surface pressures and a probe used to measure the wake characteristics. These data were recorded and processed, on-line, with a minicomputer/digital data acquisition system. The effect of both rime and glaze ice on the pressure distribution, Cl, Cd, and Cm are presented.

  12. Indirect health effects of relative humidity in indoor environments

    SciTech Connect

    Arundel, A.V.; Sterling, E.M.; Biggin, J.H.; Sterling, T.D.

    1986-03-01

    A review of the health effects of relative humidity in indoor environments suggests that relative humidity can affect the incidence of respiratory infections and allergies. Experimental studies on airborne-transmitted infectious bacteria and viruses have shown that the survival or infectivity of these organisms is minimized by exposure to relative humidities between 40 and 70%. Nine epidemiological studies examined the relationship between the number of respiratory infections or absenteeism and the relative humidity of the office, residence, or school. The incidence of absenteeism or respiratory infections was found to be lower among people working or living in environments with mid-range versus low or high relative humidities. The indoor size of allergenic mite and fungal populations is directly dependent upon the relative humidity. Mite populations are minimized when the relative humidity is below 50% and reach a maximum size at 80% relative humidity. Most species of fungi cannot grow unless the relative humidity exceeds 60%. Relative humidity also affects the rate of offgassing of formaldehyde from indoor building materials, the rate of formation of acids and salts from sulfur and nitrogen dioxide, and the rate of formation of ozone. The influence of relative humidity on the abundance of allergens, pathogens, and noxious chemicals suggests that indoor relative humidity levels should be considered as a factor of indoor air quality. The majority of adverse health effects caused by relative humidity would be minimized by maintaining indoor levels between 40 and 60%. This would require humidification during winter in areas with cold winter climates. Humidification should preferably use evaporative or steam humidifiers, as cool mist humidifiers can disseminate aerosols contaminated with allergens.

  13. Indirect health effects of relative humidity in indoor environments.

    PubMed Central

    Arundel, A V; Sterling, E M; Biggin, J H; Sterling, T D

    1986-01-01

    A review of the health effects of relative humidity in indoor environments suggests that relative humidity can affect the incidence of respiratory infections and allergies. Experimental studies on airborne-transmitted infectious bacteria and viruses have shown that the survival or infectivity of these organisms is minimized by exposure to relative humidities between 40 and 70%. Nine epidemiological studies examined the relationship between the number of respiratory infections or absenteeism and the relative humidity of the office, residence, or school. The incidence of absenteeism or respiratory infections was found to be lower among people working or living in environments with mid-range versus low or high relative humidities. The indoor size of allergenic mite and fungal populations is directly dependent upon the relative humidity. Mite populations are minimized when the relative humidity is below 50% and reach a maximum size at 80% relative humidity. Most species of fungi cannot grow unless the relative humidity exceeds 60%. Relative humidity also affects the rate of offgassing of formaldehyde from indoor building materials, the rate of formation of acids and salts from sulfur and nitrogen dioxide, and the rate of formation of ozone. The influence of relative humidity on the abundance of allergens, pathogens, and noxious chemicals suggests that indoor relative humidity levels should be considered as a factor of indoor air quality. The majority of adverse health effects caused by relative humidity would be minimized by maintaining indoor levels between 40 and 60%. This would require humidification during winter in areas with cold winter climates. Humidification should preferably use evaporative or steam humidifiers, as cool mist humidifiers can disseminate aerosols contaminated with allergens. PMID:3709462

  14. Determining the Probability of Violating Upper-Level Wind Constraints for the Launch of Minuteman Ill Ballistic Missiles At Vandenberg Air Force Base

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.; Brock, Tyler M.

    2013-01-01

    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman Ill ballistic missile. The 30 OSSWF requested the Applied Meteorology Unit (AMU) analyze VAFB sounding data to determine the probability of violating (PoV) upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a graphical user interface (GUI) that will calculate the PoV of each constraint on the day of launch. The AMU suggested also including forecast sounding data from the Rapid Refresh (RAP) model. This would provide further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours, and help to improve the overall upper winds forecast on launch day.

  15. Combined effects of wind and solar irradiance on the spatial variation of midday air temperature over a mountainous terrain

    NASA Astrophysics Data System (ADS)

    Kim, Soo-Ock; Kim, Jin-Hee; Kim, Dae-Jun; Shim, Kyo Moon; Yun, Jin I.

    2015-08-01

    When the midday temperature distribution in a mountainous region was estimated using data from a nearby weather station, the correction of elevation difference based on temperature lapse caused a large error. An empirical approach reflecting the effects of solar irradiance and advection was suggested in order to increase the reliability of the results. The normalized slope irradiance, which was determined by normalizing the solar irradiance difference between a horizontal surface and a sloping surface from 1100 to 1500 LST on a clear day, and the deviation relationship between the horizontal surface and the sloping surface at the 1500 LST temperature on each day were presented as simple empirical formulas. In order to simulate the phenomenon that causes immigrant air parcels to push out or mix with the existing air parcels in order to decrease the solar radiation effects, an advection correction factor was added to exponentially reduce the solar radiation effect with an increase in wind speed. In order to validate this technique, we estimated the 1500 LST air temperatures on 177 clear days in 2012 and 2013 at 10 sites with different slope aspects in a mountainous catchment and compared these values to the actual measured data. The results showed that this technique greatly improved the error bias and the overestimation of the solar radiation effect in comparison with the existing methods. By applying this technique to the Korea Meteorological Administration's 5-km grid data, it was possible to determine the temperature distribution at a 30-m resolution over a mountainous rural area south of Jiri Mountain National Park, Korea.

  16. Sensitivity of Global Sea-Air CO2 Flux to Gas Transfer Algorithms, Climatological Wind Speeds, and Variability of Sea Surface Temperature and Salinity

    NASA Technical Reports Server (NTRS)

    McClain, Charles R.; Signorini, Sergio

    2002-01-01

    Sensitivity analyses of sea-air CO2 flux to gas transfer algorithms, climatological wind speeds, sea surface temperatures (SST) and salinity (SSS) were conducted for the global oceans and selected regional domains. Large uncertainties in the global sea-air flux estimates are identified due to different gas transfer algorithms, global climatological wind speeds, and seasonal SST and SSS data. The global sea-air flux ranges from -0.57 to -2.27 Gt/yr, depending on the combination of gas transfer algorithms and global climatological wind speeds used. Different combinations of SST and SSS global fields resulted in changes as large as 35% on the oceans global sea-air flux. An error as small as plus or minus 0.2 in SSS translates into a plus or minus 43% deviation on the mean global CO2 flux. This result emphasizes the need for highly accurate satellite SSS observations for the development of remote sensing sea-air flux algorithms.

  17. Planar Rayleigh Scattering Results in Helium/Air Mixing Experiments in a Mach 6 Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Shirinzadeh, B.; Balla, R. Jeffrey; Hillard, M. E.; Anders, J. B.; Exton, R. J.; Waitz, I. A.

    1991-01-01

    Planar Rayleigh scattering measurements using an ArF-excimer laser have been performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach 6facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross sectional area (5 cm by 10 cm) of the flow field in the absence of clusters.

  18. Comparison of aerodynamic data measured in air and Freon-12 wind-tunnel test mediums

    NASA Technical Reports Server (NTRS)

    Weller, W. H.

    1978-01-01

    An experimental investigation was carried out to measure two dimensional static aerodynamic characteristics of a 65 sub l-213 airfoil in air and Freon-12 (dichlorodifluoromethane) test mediums at corresponding test conditions. The purpose of the tests was to compare measurements in the two test mediums and to evaluate reported methods of converting Freon-12 data to equivalent air values. The test article was a two dimensional wing instrumented to measure chordwise surface pressure distributions. The parameters considered were Mach numbers from 0.6 to 1.0, angles of attack of zero deg and 1 deg, and Reynolds numbers based on model chord from 2,000,000 to 21,000,000. The agreement between data measured in the two test mediums is further improved by application of the transonic or area ratio similarity laws. Where flow conditions are characterized by surface shocks or stall, the effects of flow separation may not be identically reflected in the Freon-12 data, even when converted in accordance with existing similarity laws.

  19. Measuring air-sea gas exchange velocities in a large scale annular wind-wave tank

    NASA Astrophysics Data System (ADS)

    Mesarchaki, E.; Kräuter, C.; Krall, K. E.; Bopp, M.; Helleis, F.; Williams, J.; Jähne, B.

    2014-06-01

    In this study we present gas exchange measurements conducted in a large scale wind-wave tank. Fourteen chemical species spanning a wide range of solubility (dimensionless solubility, α = 0.4 to 5470) and diffusivity (Schmidt number in water, Scw = 594 to 1194) were examined under various turbulent (u10 = 0.8 to 15 m s-1 conditions. Additional experiments were performed under different surfactant modulated (two different concentration levels of Triton X-100) surface states. This paper details the complete methodology, experimental procedure and instrumentation used to derive the total transfer velocity for all examined tracers. The results presented here demonstrate the efficacy of the proposed method, and the derived gas exchange velocities are shown to be comparable to previous investigations. The gas transfer behaviour is exemplified by contrasting two species at the two solubility extremes, namely nitrous oxide (N2O) and methanol (CH3OH). Interestingly, a strong transfer velocity reduction (up to a factor of three) was observed for N2O under a surfactant covered water surface. In contrast, the surfactant affected CH3OH, the high solubility tracer only weakly.

  20. An experimental wind-tunnel investigation of a ram-air-spoiler roll-control device on a forward-control missile at supersonic speeds

    NASA Technical Reports Server (NTRS)

    Blair, A. B., Jr.

    1978-01-01

    A parametric experimental wind-tunnel investigation was made at supersonic Mach numbers to provide design data on a ram-air-spoiler roll-control device that is to be used on forward-control cruciform missile configurations. The results indicate that the ram-air-spoiler tail fin is an effective roll-control device and that roll control is generally constant with vehicle attitude and Mach number unless direct canard and/or forebody shock impingement occurs. The addition of the ram-air-spoiler tail fins resulted in only small changes in aerodynamic-center location. For the ram-air-spoiler configuration tested, there are large axial force coefficient effects associated with the increased fin thickness and ram-air momentum loss.

  1. Investigations of the air flow velocity field structure above the wavy surface under severe wind conditions by particle image velosimetry technique.

    NASA Astrophysics Data System (ADS)

    Troitskaya, Yuliya; Kandaurov, Alexander; Sergeev, Daniil; Ermakova, Olga

    2013-04-01

    Preliminary experiments devoted to measuring characteristics of the air flow above the waved water surface for the wide range of wind speeds were performed with the application of modified Particle Image Velosimetry (PIV) technique. Experiments were carried out at the Wind - wave stratified flume of IAP RAS (length 10 °, cross section of air channel 0.4×0.4 m) for four different axial wind speeds: 8.7, 13.5, 19 and 24 m/s, corresponding to the equivalent 10-m wind speeds 15, 20, 30 40 m/s correspondingly. Intensive wave breaking with forming foam crest and droplets generations was occurred for two last wind conditions. The modified PIV-method based on the use of continuous-wave (CW) laser illumination of the airflow seeded by tiny particles and with highspeed video. Spherical 20 μm polyamide particles with density 1.02 g/sm3 and inertial time 7•10-3 s were used for seeding airflow with special injecting device. Green (532 nm) CW laser with 4 Wt output power was used as a source for light sheet. High speed digital camera Videosprint was used for taking visualized air flow images with the frame rate 2000 Hz s and exposure time 10 ms Combination including iteration Canny method [1] for obtaining curvilinear surface from the images in the laser sheet view and contact measurements of surface elevation by wire wave gauge installed near the border of working area for the surface wave profile was used. Then velocity air flow field was retrieved by PIV images processing with adaptive cross-correlation method on the curvilinear grid following surface wave profile. The mean wind velocity profiles were retrieved by averaging over obtained ensembles of wind velocity field realizations and over a wave period even for the cases of intensive wave breaking and droplets generation. To verify the PIV method additional measurements of mean velocity profiles over were carried out by the contact method using the Pitot tube. In the area of overlap, wind velocity profiles measured by

  2. Hydrophilic membrane-based humidity control.

    PubMed

    Scovazzo, P; Burgos, J; Hoehn, A; Todd, P

    1998-10-14

    A dehumidification system for low gravity plant growth experiments requires the generation of no free-liquid condensate and the recovery of water for reuse. In the systems discussed in this paper, the membrane is a barrier between the humid air phase and a liquid-coolant water phase. The coolant water temperature combined with a transmembrane pressure differential establishes a water flux from the humid air into the coolant water. Building on the work of others, we directly compared different hydrophilic membranes for humidity control. In a direct comparison of the hydrophilic membranes, hollow fiber cellulose ester membranes were superior to metal and ceramic membranes in the categories of condensation flux per surface area, ease of start-up, and stability. However, cellulose ester membranes were inferior to metal membranes in one significant category, durability. Dehumidification systems using mixed cellulose ester membranes failed after operational times of only hours to days. We propose that the ratio of fluid surface area to membrane material area (approximately = membrane porosity) controls the relative performances among membranes. In addition, we clarified design equations for operational parameters such as the transmembrane pressure differential. This technology has several potential benefits related to earth environmental issues including the minimization of airborne pathogen release and higher energy efficiency in air conditioning equipment. Utilizing these study results, we designed, constructed, and flew on the space shuttle missions a membrane-based dehumidification system for a plant growth chamber. PMID:11543067

  3. Performance of a wind-profiling LIDAR in the region of wind turbine rotor disks

    NASA Astrophysics Data System (ADS)

    Aitken, M.; Rhodes, M. E.; Lundquist, J. K.

    2010-12-01

    As the wind energy sector continues to grow, so does the need for reliable vertical wind profiles for assessing wind turbine performance and diagnosing underperformance issues. In situ instrumentation mounted on meteorological towers can rarely probe the atmosphere at the altitudes of modern turbine rotor disks, up to 200 m above the surface. Remote sensing LIDAR, on the other hand, can quantify winds and turbulence at altitudes throughout the ranges of modern turbine rotor disks (40 m to 200 m above the surface). By measuring the Doppler shift of laser light backscattered by particles in the atmosphere, LIDAR has proven a promising technology for both wind resource assessment and turbine response characterization; to date, however, LIDAR data availability has not been well-quantified. To determine situations of suitable data return rates, we have deployed a Windcube LIDAR, co-located with a Vaisala CL31 ceilometer, as part of the Skywatch Observatory at the University of Colorado at Boulder. Aerosol backscatter, as measured by the ceilometer, and LIDAR signal-to-noise ratio (SNR) are strongly correlated. Additionally, we find that LIDAR SNR also depends weakly on atmospheric turbulence characteristics and atmospheric relative humidity. This relationship suggests an ability to predict LIDAR performance based on widely available air quality assessments (such as the EPA Air Quality Index), thus providing guidance for useful LIDAR deployments at wind farms to characterize turbine performance. *Acknowledgments: Skywatch Observatory is funded through NSF grant 0837388.

  4. A Worldwide Plan to Eliminate Global Warming, Air Pollution, and Energy Instability With Wind, Water, and Sunlight (WWS)

    NASA Astrophysics Data System (ADS)

    Jacobson, M. Z.; Delucchi, M. A.

    2011-12-01

    Global warming, air pollution mortality, and energy insecurity are three of the most significant problems facing the world today. This talk discusses a plan to solve the problems by powering 100% of the world's energy for all purposes, including electricity, transportation, industrial processes, and heating/cooling, with wind, water, and sunlight (WWS) within the next 20-40 years. It reviews and ranks major proposed energy solutions to global warming, air pollution mortality, and energy insecurity while considering other impacts of the proposed solutions, such as on water supply, land use, resource availability, reliability, wildlife, and catastrophic risk. It then evaluates a scenario for powering the world on the energy options determined to be the best while also considering materials, transmission infrastructure, costs, and politics. The study concludes that powering the world with WWS electric power technologies and a conversion from combustion to electricity and electrolytically-produced hydrogen is the cleanest and safest method of solving these problems. Due to the efficiency of electricity, such a conversion reduces world power demand by 30%. Methods of ensuring reliability of WWS electric power are available and will be demonstrated. We also conclude that neither liquid biofuels for transportation (including ethanol or biodiesel from any source), solid biofuels for home heating and cooking, biomass for electricity, conventional or fracked natural gas for electricity or transportation, nuclear power, nor coal with carbon capture (clean coal) are nearly so clean or safe as WWS technologies so are not recommended, either as bridge technologies or in the long term. Our plan calls for all new energy to be supplied by WWS-electricity-hydrogen resources no later than 2030 and all existing non-WWS infrastructure to be eliminated no later than 2050. We find that the plan is technically and economically feasible but politically challenging.

  5. Co-location of air capture, subseafloor CO2 sequestration, and energy production on the Kerguelen plateau.

    PubMed

    Goldberg, David S; Lackner, Klaus S; Han, Patrick; Slagle, Angela L; Wang, Tao

    2013-07-01

    Reducing atmospheric CO2 using a combination of air capture and offshore geological storage can address technical and policy concerns with climate mitigation. Because CO2 mixes rapidly in the atmosphere, air capture could operate anywhere and in principle reduce CO2 to preindustrial levels. We investigate the Kerguelen plateau in the Indian Ocean, which offers steady wind resources, vast subseafloor storage capacities, and minimal risk of economic damages or human inconvenience and harm. The efficiency of humidity swing driven air capture under humid and windy conditions is tested in the laboratory. Powered by wind, we estimate ∼75 Mt CO2/yr could be collected using air capture and sequestered below seafloor or partially used for synfuel. Our analysis suggests that Kerguelen offers a remote and environmentally secure location for CO2 sequestration using renewable energy. Regional reservoirs could hold over 1500 Gt CO2, sequestering a large fraction of 21st century emissions. PMID:23745611

  6. Net sea-air CO2 flux uncertainties in the Bay of Biscay based on the choice of wind speed products and gas transfer parameterizations

    NASA Astrophysics Data System (ADS)

    Otero, P.; Padin, X. A.; Ruiz-Villarreal, M.; García-García, L. M.; Ríos, A. F.; Pérez, F. F.

    2013-05-01

    The estimation of sea-air CO2 fluxes is largely dependent on wind speed through the gas transfer velocity parameterization. In this paper, we quantify uncertainties in the estimation of the CO2 uptake in the Bay of Biscay resulting from the use of different sources of wind speed such as three different global reanalysis meteorological models (NCEP/NCAR 1, NCEP/DOE 2 and ERA-Interim), one high-resolution regional forecast model (HIRLAM-AEMet), winds derived under the Cross-Calibrated Multi-Platform (CCMP) project, and QuikSCAT winds in combination with some of the most widely used gas transfer velocity parameterizations. Results show that net CO2 flux estimations during an entire seasonal cycle (September 2002-September 2003) may vary by a factor of ~ 3 depending on the selected wind speed product and the gas exchange parameterization, with the highest impact due to the last one. The comparison of satellite- and model-derived winds with observations at buoys advises against the systematic overestimation of NCEP-2 and the underestimation of NCEP-1. In the coastal region, the presence of land and the time resolution are the main constraints of QuikSCAT, which turns CCMP and ERA-Interim in the preferred options.

  7. Responses of sap flow, leaf gas exchange and growth of hybrid aspen to elevated atmospheric humidity under field conditions

    PubMed Central

    Niglas, Aigar; Kupper, Priit; Tullus, Arvo; Sellin, Arne

    2014-01-01

    An increase in average air temperature and frequency of rain events is predicted for higher latitudes by the end of the 21st century, accompanied by a probable rise in air humidity. We currently lack knowledge on how forest trees acclimate to rising air humidity in temperate climates. We analysed the leaf gas exchange, sap flow and growth characteristics of hybrid aspen (Populus tremula × P. tremuloides) trees growing at ambient and artificially elevated air humidity in an experimental forest plantation situated in the hemiboreal vegetation zone. Humidification manipulation did not affect the photosynthetic capacity of plants, but did affect stomatal responses: trees growing at elevated air humidity had higher stomatal conductance at saturating photosynthetically active radiation (gs sat) and lower intrinsic water-use efficiency (IWUE). Reduced stomatal limitation of photosynthesis in trees grown at elevated air humidity allowed slightly higher net photosynthesis and relative current-year height increments than in trees at ambient air humidity. Tree responses suggest a mitigating effect of higher air humidity on trees under mild water stress. At the same time, trees at higher air humidity demonstrated a reduced sensitivity of IWUE to factors inducing stomatal closure and a steeper decline in canopy conductance in response to water deficit, implying higher dehydration risk. Despite the mitigating impact of increased air humidity under moderate drought, a future rise in atmospheric humidity at high latitudes may be disadvantageous for trees during weather extremes and represents a potential threat in hemiboreal forest ecosystems. PMID:24887000

  8. Responses of sap flow, leaf gas exchange and growth of hybrid aspen to elevated atmospheric humidity under field conditions.

    PubMed

    Niglas, Aigar; Kupper, Priit; Tullus, Arvo; Sellin, Arne

    2014-01-01

    An increase in average air temperature and frequency of rain events is predicted for higher latitudes by the end of the 21st century, accompanied by a probable rise in air humidity. We currently lack knowledge on how forest trees acclimate to rising air humidity in temperate climates. We analysed the leaf gas exchange, sap flow and growth characteristics of hybrid aspen (Populus tremula × P. tremuloides) trees growing at ambient and artificially elevated air humidity in an experimental forest plantation situated in the hemiboreal vegetation zone. Humidification manipulation did not affect the photosynthetic capacity of plants, but did affect stomatal responses: trees growing at elevated air humidity had higher stomatal conductance at saturating photosynthetically active radiation (gs sat) and lower intrinsic water-use efficiency (IWUE). Reduced stomatal limitation of photosynthesis in trees grown at elevated air humidity allowed slightly higher net photosynthesis and relative current-year height increments than in trees at ambient air humidity. Tree responses suggest a mitigating effect of higher air humidity on trees under mild water stress. At the same time, trees at higher air humidity demonstrated a reduced sensitivity of IWUE to factors inducing stomatal closure and a steeper decline in canopy conductance in response to water deficit, implying higher dehydration risk. Despite the mitigating impact of increased air humidity under moderate drought, a future rise in atmospheric humidity at high latitudes may be disadvantageous for trees during weather extremes and represents a potential threat in hemiboreal forest ecosystems. PMID:24887000

  9. 77 FR 485 - Wind Plant Performance-Public Meeting on Modeling and Testing Needs for Complex Air Flow...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-05

    ... of Energy Efficiency and Renewable Energy Wind Plant Performance--Public Meeting on Modeling and... validation techniques for complex flow phenomena in and around off- shore and on-shore utility-scale wind power plants. DOE is requesting this information to support the development of cost-effective wind...

  10. Ground-level climate at a peatland wind farm in Scotland is affected by wind turbine operation

    NASA Astrophysics Data System (ADS)

    Armstrong, Alona; Burton, Ralph R.; Lee, Susan E.; Mobbs, Stephen; Ostle, Nicholas; Smith, Victoria; Waldron, Susan; Whitaker, Jeanette

    2016-04-01

    The global drive to produce low-carbon energy has resulted in an unprecedented deployment of onshore wind turbines, representing a significant land use change for wind energy generation with uncertain consequences for local climatic conditions and the regulation of ecosystem processes. Here, we present high-resolution data from a wind farm collected during operational and idle periods that shows the wind farm affected several measures of ground-level climate. Specifically, we discovered that operational wind turbines raised air temperature by 0.18 °C and absolute humidity (AH) by 0.03 g m‑3 during the night, and increased the variability in air, surface and soil temperature throughout the diurnal cycle. Further, the microclimatic influence of turbines on air temperature and AH decreased logarithmically with distance from the nearest turbine. These effects on ground-level microclimate, including soil temperature, have uncertain implications for biogeochemical processes and ecosystem carbon cycling, including soil carbon stocks. Consequently, understanding needs to be improved to determine the overall carbon balance of wind energy.

  11. Design of single-winding energy-storage reactors for dc-to-dc converters using air-gapped magnetic-core structures

    NASA Technical Reports Server (NTRS)

    Ohri, A. K.; Wilson, T. G.; Owen, H. A., Jr.

    1977-01-01

    A procedure is presented for designing air-gapped energy-storage reactors for nine different dc-to-dc converters resulting from combinations of three single-winding power stages for voltage stepup, current stepup and voltage stepup/current stepup and three controllers with control laws that impose constant-frequency, constant transistor on-time and constant transistor off-time operation. The analysis, based on the energy-transfer requirement of the reactor, leads to a simple relationship for the required minimum volume of the air gap. Determination of this minimum air gap volume then permits the selection of either an air gap or a cross-sectional core area. Having picked one parameter, the minimum value of the other immediately leads to selection of the physical magnetic structure. Other analytically derived equations are used to obtain values for the required turns, the inductance, and the maximum rms winding current. The design procedure is applicable to a wide range of magnetic material characteristics and physical configurations for the air-gapped magnetic structure.

  12. Frost Growth and Densification on a Flat Surface in Laminar Flow with Variable Humidity

    NASA Technical Reports Server (NTRS)

    Kandula, M.

    2012-01-01

    Experiments are performed concerning frost growth and densification in laminar flow over a flat surface under conditions of constant and variable humidity. The flat plate test specimen is made of aluminum-6031, and has dimensions of 0.3 mx0.3 mx6.35 mm. Results for the first variable humidity case are obtained for a plate temperature of 255.4 K, air velocity of 1.77 m/s, air temperature of 295.1 K, and a relative humidity continuously ranging from 81 to 54%. The second variable humidity test case corresponds to plate temperature of 255.4 K, air velocity of 2.44 m/s, air temperature of 291.8 K, and a relative humidity ranging from 66 to 59%. Results for the constant humidity case are obtained for a plate temperature of 263.7 K, air velocity of 1.7 m/s, air temperature of 295 K, and a relative humidity of 71.6 %. Comparisons of the data with the author's frost model extended to accommodate variable humidity suggest satisfactory agreement between the theory and the data for both constant and variable humidity.

  13. Modeling of urbanization effect on the simulation of wind fields in urban building environments and its application to air quality studies

    NASA Astrophysics Data System (ADS)

    Jeong, J. H.; Kim, Y. K.

    2014-12-01

    The effect of urbanization on the simulation of wind fields and air quality in urban building environments was evaluated. The urban canopy model (UCM) parameterizations coupled to the WRF model were used to study urban processes, and their effect on the diurnal evolution of boundary layer structure in urban building environments. The study domain for modeling is the Seoul metropolitan area, which is typical urban building environment with high-densities and a broad range of multi-stories buildings. To create and compare urban land surface, the land cover was extracted from the Environmental Geographic Information System and the spatial data of the Seoul Metropolitan area for the Biotope Mapping Project. To apply UCM parameterization, the classification of urban surfaces was conducted. For the analysis, several meteorological variables were used during two specific time periods, i.e., day and night. Overall, large differences in wind fields were shown distinctly by urbanization effect. However, the magnitude of the differences was distinguished between the time periods. The differences in the wind components by urbanization effect were somewhat stronger during the day than at night, and it was likely that the marked decrease in the wind speed during the day was mainly caused by increased mechanical drag, turbulence production, and thermal effects. The urbanization effect showed a decrease of wind speed in the urban canopy layer for two specific times. Moreover, the urbanization effect on the simulation of wind fields was applied to air quality studies in urban building environments. Acknowledgements: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2010-0012045).

  14. A diagram of wind speed versus air-sea temperature difference to understand the dynamics of the marine atmospheric boundary layer off northwest Europe

    NASA Astrophysics Data System (ADS)

    Kettle, Anthony

    2015-04-01

    Wind speed and atmospheric stability have an important role in determining the turbulence in the marine atmospheric boundary layer (MABL) as well as the surface wave field. The understanding of MABL dynamics in northwest Europe is complicated by fetch effects, the proximity of coastlines, shallow topography, and larger scale circulation patterns (e.g., cold air outbreaks). Numerical models have difficulty simulating the marine atmospheric boundary layer in coastal areas and partially enclosed seas, and this is partly due to spatial resolution problems at land-sea coastline discontinuities. In these offshore environments, the boundary layer processes are often best understood directly from time series measurements from measurement platforms or buoys, in spite of potential difficulties from platform flow distortion as well as the spatial sparseness of the data sets. This contribution presents updated results of measurements from offshore platforms in the North Sea and Norwegian Sea in terms of a summary diagnostic - wind speed versus air-sea temperature difference (U-ΔT) - with important implications for understanding atmospheric boundary layer processes. The U-ΔT diagram was introduced in earlier surveys of data from coastal and offshore sites in northwest Europe to summarize boundary layer conditions at a given location. Additional information from a series of measurement purpose-built offshore measurement and oil/gas production platforms from the North Sea illustrates how the wind characteristics vary spatially over large distances. The results are important for the offshore wind industry because of the way that wind turbines accrue fatigue damage in different conditions of atmospheric stability and wind speed.

  15. Hover and wind-tunnel testing of shrouded rotors for improved micro air vehicle design

    NASA Astrophysics Data System (ADS)

    Pereira, Jason L.

    The shrouded-rotor configuration has emerged as the most popular choice for rotary-wing Micro Air Vehicles (MAVs), because of the inherent safety of the design and the potential for significant performance improvements. However, traditional design philosophies based on experience with large-scale ducted propellers may not apply to the low-Reynolds-number (˜20,000) regime in which MAVs operate. An experimental investigation of the effects of varying the shroud profile shape on the performance of MAV-scale shrouded rotors has therefore been conducted. Hover tests were performed on seventeen models with a nominal rotor diameter of 16 cm (6.3 in) and various values of diffuser expansion angle, diffuser length, inlet lip radius and blade tip clearance, at various rotor collective angles. Compared to the baseline open rotor, the shrouded rotors showed increases in thrust by up to 94%, at the same power consumption, or reductions in power by up to 62% at the same thrust. These improvements surpass those predicted by momentum theory, due to the additional effect of the shrouds in reducing the non-ideal power losses of the rotor. Increasing the lip radius and decreasing the blade tip clearance caused performance to improve, while optimal values of diffuser angle and length were found to be 10 and 50% of the shroud throat diameter, respectively. With the exception of the lip radius, the effects of changing any of the shrouded-rotor parameters on performance became more pronounced as the values of the other parameters were changed to degrade performance. Measurements were also made of the wake velocity profiles and the shroud surface pressure distributions. The uniformity of the wake was improved by the presence of the shrouds and by decreasing the blade tip clearance, resulting in lower induced power losses. For high net shroud thrust, a favorable pressure distribution over the inlet was seen to be more important than in the diffuser. Strong suction pressures were observed

  16. Fiberboard Humidity Data for 9975 Shipping Packages

    SciTech Connect

    Daugherty, W.

    2015-07-31

    The 9975 surveillance program is identifying a technical basis to support extending the storage period of 9975 packages in KAC beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis. Two efforts have been undertaken to better understand the levels and behavior of moisture within the fiberboard assemblies of the 9975 shipping package. In the first effort, an initial survey of humidity and temperature in the upper air space of 26 packages stored in KAC was made. The data collected within this first effort help to illustrate how the upper air space humidity varies with the local ambient temperature and package heat load. In the second effort, direct measurements of two test packages are providing a correlation between humidity and fiberboard moisture levels within the package, and variations in moisture throughout the fiberboard assembly. This effort has examined packages with cane fiberboard and internal heat levels of 5 and 10W to date. Additional testing is expected to include 15 and 19W heat levels, and then repeat the same four heat levels with softwood fiberboard assemblies. This report documents the data collected to date within these two efforts

  17. Fiberboard humidity data for 9975 shipping packages

    SciTech Connect

    Daugherty, W. L.

    2015-07-31

    The 9975 surveillance program is identifying a technical basis to support extending the storage period of 9975 packages in KAC beyond the currently approved 15 years. A key element of this effort is developing a better understanding of degradation of the fiberboard assembly under storage conditions. This degradation is influenced greatly by the moisture content of the fiberboard, which is not well characterized on an individual package basis.Two efforts have been undertaken to better understand the levels and behavior of moisture within the fiberboard assemblies of the 9975 shipping package. In the first effort, an initial survey of humidity and temperature in the upper air space of 26 packages stored in KAC was made. The data collected within this first effort help to illustrate how the upper air space humidity varies with the local ambient temperature and package heat load. In the second effort, direct measurements of two test packages are providing a correlation between humidity and fiberboard moisture levels within the package, and variations in moisture throughout the fiberboard assembly. This effort has examined packages with cane fiberboard and internal heat levels of 5 and 10W to date. Additional testing is expected to include 15 and 19W heat levels, and then repeat the same four heat levels with softwood fiberboard assemblies. This report documents the data collected to date within these two efforts.

  18. A wind tunnel study of the flow field within and around open-top chambers used for air pollution studies

    NASA Astrophysics Data System (ADS)

    Davis, J. M.; Riordan, A. J.; Lawson, R. E.

    1983-02-01

    The EPA Meteorological Wind Tunnel was used to examine the flow field in and around models of open-top field-plant growth chambers used to assess the effects of pollutant gases on plant growth. Baffles designed to reduce the ingress of ambient air into the chamber through the open top were tested; the mean flow and turbulence in the simulated boundary layer with and without the chambers were compared (the chamber was operated with and without the pollutant flow system on); and the effects of surrounding chambers on the concentration field were measured. Results showed that a baffle with a reduced opening vertically above the test area maintained the highest uniform concentration in the test area. The major differences between the three (no chamber and the chamber with flow on and off) mean velocity profiles occurred below z/h = 2.0 ( h is chamber height) and at z/h ≤ 4.2. The three Reynolds stress profiles were similar above z/h = 2.0. Downwind of the chamber, the Reynolds stresses in the on-mode were greater than those in the off-mode above z/h = 1.1. The reverse was true below that point. Both longitudinal and vertical intensities above and downwind of the chamber were greater with the mixture flow system on rather than off, below about z/h < 1.5. Lateral variations in the mean wind indicated that the mean velocity was greater with the mixture flow system on except near the centerline where the reverse was true. The concentrations in the downwind wake resembled those for a cube. The location of a cylinder within a regular array had some effect on its internal gas concentration. Locations near the upwind and downwind edges of the array were associated with lower concentrations, although for all locations the highest internal values were always found at the lowest portion of the upwind wall. With active cylinders downwind, the gas plume emitted from a source cylinder at the windward edge of the array was forced 0.5 h higher and the centerline meandered laterally

  19. Building for the Pacific Rim Countries. Energy-efficient building strategies for hot, humid climates

    SciTech Connect

    Sheinkopf, K.

    1991-09-01

    This book has been published by the Solar Energy Industries Association (SEIA), the US trade association of the solar thermal, photovoltaic, and passive solar manufacturers, distributors, and component suppliers. Its purpose is to help architects, builders, and developers construct energy-efficient homes in hot humid climates like the Pacific Rim Countries, and to allow occupants of these homes to enjoy enhanced comfort without reliance on mechanical air-conditioning systems. Two important factors are addressed in this book. First, the past few years have seen a tremendous increase in practical applications of new research. The current popularity of ceiling paddle fans, attic radiant barriers and natural daylighting attest to the importance of keeping up with the latest concepts in energy-reduction and comfort-awareness. Professionals who have been in the field for the past few years may be unaware of the latest research findings--some of which dramatically alter prior thinking on such subjects as natural ventilation or mechanical air conditioning. The second factor is the importance of site-specific characteristics, which greatly affect building strategies and designs. A thorough understanding of the climate is a prerequisite to good building design. Such factors as temperature, humidity, wind speed and direction, and solar radiation must be understood and properly integrated into the design for the home to be truly energy-efficient.

  20. Air-sea interaction with SSM/I and altimeter

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A number of important developments in satellite remote sensing techniques have occurred recently which offer the possibility of studying over vast areas of the ocean the temporally evolving energy exchange between the ocean and the atmosphere. Commencing in spring of 1985, passive and active microwave sensors that can provide valuable data for scientific utilization will start to become operational on Department of Defense (DOD) missions. The passive microwave radiometer can be used to estimate surface wind speed, total air column humidity, and rain rate. The active radar, or altimeter, senses surface gravity wave height and surface wind speed.

  1. Crystal Microbalance Monitors Relative Humidity

    NASA Technical Reports Server (NTRS)

    Yang, L. C.

    1984-01-01

    Sensor monitors water evaporation in industrial drying processes. Measured adsorption isotherm for instrument essentially linear over entire range of relative humidity. Testing at each temperature setting less than half hour for full relative-humidity range, with estimated frequency response time less than 10 seconds. Used to measure relative humidity of ambient atmosphere near drying paper, food textile fabrics and pulp to optimize water-drying portion of processing cycle.

  2. Proposal and Development of Radial Air-gap Coreless Generator Suitable for Small Wind Turbine using in Urban Area

    NASA Astrophysics Data System (ADS)

    Takahashi, Toshiyuki; Yasuda, Yoh; Ohmoto, Shingo; Hara, Takehisa

    Independent distributed generations using small wind turbines are widely spread as increasing of wind power generation. Installation of small wind turbines in densely-populated urban area is not only useful from the viewpoint of digging up wind power source in weak-wind area but also for enlightenment of renewable energy due to closing power supplies to consumptions. From the point of view, the authors proposed “urban wind power generation" using collective system with a number of small vertical wind turbines and have developed a suitable generator for low-speed vertical wind turbines such as Savonius windmill. Standardized on a coreless generator, the proposed generator is designed to let direction of magnetic fluxes radial in order to install the magnets and coils on the outer end of the generator. The change of magnet composition and flux direction gives realization of maximized speed of flux change and output voltage in the limited space. With above composition, the power of the proposed one is independent on the diameter. In this report, we describe evaluated fundamental performance of a prototype of the proposed generator. As the result of the experiments, the maximum output power of 283W was obtained. The obtained starting torque is enough small to begin to rotate at weak wind condition of no more than 1m/s. Therefore, it is clear that the proposed “radial” coreless generator is suitable for self-starting and producing high power at low speed wind.

  3. Mesoscale variability of free tropospheric humidity near San Nicolas Island during FIRE

    NASA Technical Reports Server (NTRS)

    White, A. B.; Fairall, C. W.; Thomson, D. W.

    1990-01-01

    Humidity variability at the top of the marine boundary layer (MBL) and in the free troposphere was examined using a variety of measurements taken on and around San Nicolas Island (SNI) during the FIRE IFO in July, 1987. Doppler wind profiler reflectivity recorded at two minute time resolution has provided the most continuous record and detail of small scale humidity fluctuations. Rawinsonde data were available from both an island site and the research vessel Point Sur. The information extractable from these sources is somewhat limited due to the frequency of launches (3 to 4/day at SNI and 6/day on the Point Sur). Some additional data were available from instrumented aircraft although scheduling flights in the neighborhood of the island was difficult due to restrictions on the air space. Other relevant data were collected at SNI near the radar and rawinsonde launch sites. A continuous record of cloud base altitude was logged by a ceilometer. Doppler acoustic sounder (sodar) reflectivity data provided a good record of inversion height. The sodar also monitored turbulent temperature fluctuations in the MBL. A small ground station recorded hourly averages of solar irradiance and downward longwave irradiance. The analysis in progress of the various data sets for two adjacent two day periods from 11 July to 14 July is described. The earlier period was chosen because the marine inversion was unusually high and there was increased frequency of rawinsonde launches at SNI. The later period was chosen because of the significant descent with time of an elevated inversion indicated by the radar data. Throughout the four day period, but especially in the first half, the turbulent humidity structure calculated from Doppler radar reflectivity shows excellent agreement with humidity profiles evaluated from rawinsonde data.

  4. Net sea-air CO2 flux uncertainties in the Bay of Biscay based on the choice of wind speed products and gas transfer parameterizations

    NASA Astrophysics Data System (ADS)

    Otero, P.; Padín, X. A.; Ruiz-Villarreal, M.; García-García, L. M.; Ríos, A. F.; Pérez, F. F.

    2012-08-01

    The estimation of sea-air CO2 fluxes are largely dependent on wind speed through the gas transfer velocity parameterization. In this paper, we quantify uncertainties in the estimation of the CO2 uptake in the Bay of Biscay resulting from using different sources of wind speed such as three different global reanalysis meteorological models (NCEP/NCAR 1, NCEP/DOE 2 and ERA-Interim), one regional high-resolution forecast model (HIRLAM-AEMet) and QuikSCAT winds, in combination with some of the most widely used gas transfer velocity parameterizations. Results show that net CO2 flux estimations during an entire seasonal cycle may differ up to 240% depending on the wind speed product and the gas exchange parameterization. The comparison of satellite and model derived winds with observations at buoys advises against the systematic overestimation of NCEP-2 and the underestimation of NCEP-1. In this region, QuikSCAT has the best performing, although ERA-Interim becomes the best choice in areas near the coastline or when the time resolution is the constraint.

  5. The relationship between the microwave radar cross section and both wind speed and stress: Model function studies using Frontal Air-Sea Interaction Experiment data

    NASA Technical Reports Server (NTRS)

    Weissman, David E.; Davidson, Kenneth L.; Brown, Robert A.; Friehe, Carl A.; Li, Fuk

    1994-01-01

    The Frontal Air-Sea Interaction Experiment (FASINEX) provided a unique data set with coincident airborne scatterometer measurements of the ocean surface radar cross section (RCS)(at Ku band) and near-surface wind and wind stress. These data have been analyzed to study new model functions which relate wind speed and surface friction velocity (square root of the kinematic wind stress) to the radar cross section and to better understand the processes in the boundary layer that have a strong influence on the radar backscatter. Studies of data from FASINEX indicate that the RCS has a different relation to the friction velocity than to the wind speed. The difference between the RCS models using these two variables depends on the polarization and the incidence angle. The radar data have been acquired from the Jet Propulsion Laboratory airborne scatterometer. These data span 10 different flight days. Stress measurements were inferred from shipboard instruments and from aircraft flying at low altitudes, closely following the scatterometer. Wide ranges of radar incidence angles and environmental conditions needed to fully develop algorithms are available from this experiment.

  6. Biometeorological classification of daily weather types for the humid tropics

    NASA Astrophysics Data System (ADS)

    Lecha Estela, Luis B.

    This paper describes the methodology for an objective classification of weather types for biometeorological purposes in a tropical-humid climate, such as the Cuban climate. The classification considers the daily behavior of extreme air temperatures, the mean partial vapor pressure, the mean diurnal cloudiness, the wind speed at 1300 hours local time, and the occurrence of precipitation during the day, in order to identify up to 18 weather types. Descriptions are given of the main biometeorological characteristics of some significant weather types, considering typical geographical locations, and their seasonal variations related to the seasonal pattern of asthma and acute respiratory infections. The relationship between the daily occurrence of diseases and the distribution of these local weather types is also discribed. A significant relationship was found between the incidence of cardiovascular and neurological diseases and the occurrence of hot stress, while the presence of cold and very cold days was closely related with increases of bronchial asthma in adults and children. The appearance of large meteoropathological reactions in the native population could be explained by the day to day pattern of change in the weather types.

  7. Improving irrigation management for humid and sub-humid climates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This project includes studies led by both USDA-ARS and University of Missouri scientists, with a goal to develop solutions to broad water management problems with application to humid and sub-humid areas in the USA and the world. Our interdisciplinary team optimizes production systems for irrigated ...

  8. Improving irrigation management for humid and sub-humid climates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This project includes studies led by both USDA-ARS and University of Missouri scientists, with a goal to develop solutions to broad water management problems with application to humid and sub-humid areas in the USA and the world. Our interdisciplinary team evaluates and optimizes production systems ...

  9. Upper tropospheric humidity changes under constant relative humidity

    NASA Astrophysics Data System (ADS)

    Gierens, Klaus; Eleftheratos, Kostas

    2016-03-01

    Theoretical derivations are given on the change of upper tropospheric humidity (UTH) in a warming climate. The considered view is that the atmosphere, which is getting moister with increasing temperatures, will retain a constant relative humidity. In the present study, we show that the upper tropospheric humidity, a weighted mean over a relative humidity profile, will change in spite of constant relative humidity. The simple reason for this is that the weighting function that defines UTH changes in a moister atmosphere. Through analytical calculations using observations and through radiative transfer calculations, we demonstrate that two quantities that define the weighting function of UTH can change: the water vapour scale height and the peak emission altitude. Applying these changes to real profiles of relative humidity shows that absolute UTH changes typically do not exceed 1 %. If larger changes would be observed they would be an indication of climatological changes of relative humidity. As such, an increase in UTH between 1980 and 2009 in the northern midlatitudes, as shown by earlier studies using the High-resolution Infrared Radiation Sounder (HIRS) data, may be an indication of an increase in relative humidity as well.

  10. Upper-tropospheric humidity changes under constant relative humidity

    NASA Astrophysics Data System (ADS)

    Gierens, K.; Eleftheratos, K.

    2015-10-01

    Theoretical derivations are given on the change of upper-tropospheric humidity (UTH) in a warming climate. Considered view is that the atmosphere, getting moister with increasing temperatures, will retain a constant relative humidity. In the present study we show that the upper-tropospheric humidity, a weighted mean over a relative humidity profile, will change in spite of constant relative humidity. The simple reason for this is that the weighting function, that defines UTH, changes in a moister atmosphere. Through analytical calculations using observations and through radiative transfer calculations we demonstrate that two quantities that define the weighting function of UTH can change: the water vapour scale height and the peak emission altitude. Applying these changes to real profiles of relative humidity shows that absolute UTH changes typically do not exceed 1 %. If larger changes would be observed they would be an indication of climatological changes of relative humidity. As such, an increase in UTH between 1980 and 2009 in the northern midlatitudes as shown by earlier studies using HIRS data, may be an indication of an increase in relative humidity as well.

  11. Humidity Graphs for All Seasons.

    ERIC Educational Resources Information Center

    Esmael, F.

    1982-01-01

    In a previous article in this journal (Vol. 17, p358, 1979), a wet-bulb depression table was recommended for two simple experiments to determine relative humidity. However, the use of a graph is suggested because it gives the relative humidity directly from the wet and dry bulb readings. (JN)

  12. Wind tunnel investigation of an all flush orifice air data system for a large subsonic aircraft. [conducted in a Langley 8 foot transonic pressure tunnel

    NASA Technical Reports Server (NTRS)

    Larson, T. J.; Flechner, S. G.; Siemers, P. M., III

    1980-01-01

    The results of a wind tunnel investigation on an all flush orifice air data system for use on a KC-135A aircraft are presented. The investigation was performed to determine the applicability of fixed all flush orifice air data systems that use only aircraft surfaces for orifices on the nose of the model (in a configuration similar to that of the shuttle entry air data system) provided the measurements required for the determination of stagnation pressure, angle of attack, and angle of sideslip. For the measurement of static pressure, additional flush orifices in positions on the sides of the fuselage corresponding to those in a standard pitot-static system were required. An acceptable but less accurate system, consisting of orifices only on the nose of the model, is defined and discussed.

  13. EVALUATING THE EFFICACY OF A WOOD-STRAND MATERIAL FOR WIND EROSION MITIGATION AND AIR QUALITY PROTECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arid conditions and persistent winds are characteristic of much of the western United States and provide a climate conducive to wind erosion. Airborne dust generated from exposed soil at construction sites, post–wildfire events, and farm fields is a widespread problem with both human health and envi...

  14. Entropy and Mixing : Titan's Humidity Revisited

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2003-05-01

    Determinations of the relative humidity of methane near Titan's surface range from 40-60 %. The rationale advanced by Lunine in the global ocean hypothesis was that a mixed ethane-methane ocean in thermodynamic equilibrium with the atmosphere would be unsaturated due to methane vapor pressure supression by involatile ethane (much as salt or sugar dissolved in water slows its evaporation). Here I explore a nonequilibrium explanation for the incomplete saturation - the reason why the terrestrial atmosphere is not saturated. Specifically, saturated near-surface air is mixed with downwelling dry air, a mixing driven by vertical convection. The more vigorous the mixing, the dryer the near-surface air should be. Flasar (1983) made a crude empirical evaluation of transport processes : here I adopt a more fundamental thermodynamic approach. In reality both the involatile solute and the mixing mechanisms probably play a part in regulating methane humidity, and the utility of global and annual averages must be compromised by latitudinal and seasonal dependences. Comparison with the Earth - where moist processes play a dominant role in the entropy budget - will be instructive.

  15. Separating the influence of projected changes in air temperature and wind on patterns of sea level change and ocean heat content

    NASA Astrophysics Data System (ADS)

    Saenko, Oleg A.; Yang, Duo; Gregory, Jonathan M.; Spence, Paul; Myers, Paul G.

    2015-08-01

    We present ocean model sensitivity experiments aimed at separating the influence of the projected changes in the "thermal" (near-surface air temperature) and "wind" (near-surface winds) forcing on the patterns of sea level and ocean heat content. In the North Atlantic, the distribution of sea level change is more due to the "thermal" forcing, whereas it is more due to the "wind" forcing in the North Pacific; in the Southern Ocean, the "thermal" and "wind" forcing have a comparable influence. In the ocean adjacent to Antarctica the "thermal" forcing leads to an inflow of warmer waters on the continental shelves, which is somewhat attenuated by the "wind" forcing. The structure of the vertically integrated heat uptake is set by different processes at low and high latitudes: at low latitudes it is dominated by the heat transport convergence, whereas at high latitudes it represents a small residual of changes in the surface flux and advection of heat. The structure of the horizontally integrated heat content tendency is set by the increase of downward heat flux by the mean circulation and comparable decrease of upward heat flux by the subgrid-scale processes; the upward eddy heat flux decreases and increases by almost the same magnitude in response to, respectively, the "thermal" and "wind" forcing. Regionally, the surface heat loss and deep convection weaken in the Labrador Sea, but intensify in the Greenland Sea in the region of sea ice retreat. The enhanced heat flux anomaly in the subpolar Atlantic is mainly caused by the "thermal" forcing.

  16. A comparison between Nimbus 5 THIR and ITPR temperatures and derived winds with rawinsonde data obtained in the AVE II experiment. [Temperature-Humidity Infrared Radiometer and Infrared Temperature Profile Radiometer

    NASA Technical Reports Server (NTRS)

    Arnold, J. E.; Scoggins, J. R.; Fuelberg, H. E.

    1977-01-01

    During the second Atmospheric Variability Experiment (AVE II), atmospheric temperature profiles were computed from Nimbus 5 data, which comprised ITPR, NEMS, and SCR measurements. Rawinsonde data were obtained from NWS stations in the AVE II network and processed for each pressure contact; the soundings closest in space and time were interpolated to the Nimbus 5 sounding points for comparison purposes. Cross sections of thermal and geostrophic winds were computed from satellite-derived cross sections of temperature along the Nimbus orbital track.

  17. Greenhouse gas and air pollutant emission reduction potentials of renewable energy--case studies on photovoltaic and wind power introduction considering interactions among technologies in Taiwan.

    PubMed

    Kuo, Yu-Ming; Fukushima, Yasuhiro

    2009-03-01

    To achieve higher energy security and lower emission of greenhouse gases (GHGs) and pollutants, the development of renewable energy has attracted much attention in Taiwan. In addition to its contribution to the enhancement of reliable indigenous resources, the introduction of renewable energy such as photovoltaic (PV) and wind power systems reduces the emission of GHGs and air pollutants by substituting a part of the carbon- and pollutant-intensive power with power generated by methods that are cleaner and less carbon-intensive. To evaluate the reduction potentials, consequential changes in the operation of different types of existing power plants have to be taken into account. In this study, a linear mathematical programming model is constructed to simulate a power mix for a given power demand in a power market sharing a cost-minimization objective. By applying the model, the emission reduction potentials of capacity extension case studies, including the enhancement of PV and wind power introduction at different scales, were assessed. In particular, the consequences of power mix changes in carbon dioxide, nitrogen oxides, sulfur oxides, and particulates were discussed. Seasonally varying power demand levels, solar irradiation, and wind strength were taken into account. In this study, we have found that the synergetic reduction of carbon dioxide emission induced by PV and wind power introduction occurs under a certain level of additional installed capacity. Investigation of a greater variety of case studies on scenario development with emerging power sources becomes possible by applying the model developed in this study. PMID:19320274

  18. Tool for Forecasting Cool-Season Peak Winds Across Kennedy Space Center and Cape Canaveral Air Force Station (CCAFS)

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Roeder, William P.

    2010-01-01

    Peak wind speed is important element in 24-Hour and Weekly Planning Forecasts issued by 45th Weather Squadron (45 WS). Forecasts issued for planning operations at KSC/CCAFS. 45 WS wind advisories issued for wind gusts greater than or equal to 25 kt. 35 kt and 50 kt from surface to 300 ft. AMU developed cool-season (Oct - Apr) tool to help 45 WS forecast: daily peak wind speed, 5-minute average speed at time of peak wind, and probability peak speed greater than or equal to 25 kt, 35 kt, 50 kt. AMU tool also forecasts daily average wind speed from 30 ft to 60 ft. Phase I and II tools delivered as a Microsoft Excel graphical user interface (GUI). Phase II tool also delivered as Meteorological Interactive Data Display System (MIDDS) GUI. Phase I and II forecast methods were compared to climatology, 45 WS wind advisories and North American Mesoscale model (MesoNAM) forecasts in a verification data set.

  19. Validation and development of existing and new RAOB-based warm-season convective wind forecasting tools for Cape Canaveral Air Force Station and Kennedy Space Center

    NASA Astrophysics Data System (ADS)

    McCue, Mitchell Hollis

    Using a 15-year (1995 to 2009) climatology of 1500 UTC warm-season (May through September) rawinsonde observation (RAOB) data from the Cape Canaveral Air Force Station (CCAFS) Skid Strip (KXMR) and 5 minute wind data from 36 wind towers on CCAFS and Kennedy Space Center (KSC), several convective wind forecasting techniques currently employed by the 45th Weather Squadron (45 WS) were evaluated. Present forecasting methods under evaluation include examining the vertical equivalent potential temperature (theta e) profile, vertical profiles of wind spend and direction, and several wet downburst forecasting indices. Although previous research found that currently used wet downburst forecasting methods showed little promise for forecasting convective winds, it was carried out with a very small sample, limiting the reliability of the results. Evaluation versus a larger 15-year dataset was performed to truly assess the forecasting utility of these methods in the central Florida warm-season convective environment. In addition, several new predictive analytic based forecast methods for predicting the occurrence of warm-season convection and its associated wind gusts were developed and validated. This research was performed in order to help the 45 WS better forecast not only which days are more likely to produce convective wind gusts, but also to better predict which days are more likely to yield warning criteria wind events of 35 knots or greater, should convection be forecasted. Convective wind forecasting is a very challenging problem that requires new statistically based modeling techniques since conventional meteorologically based methods do not perform well. New predictive analytic based forecasting methods were constructed using R statistical software and incorporate several techniques including multiple linear regression, logistic regression, multinomial logistic regression, classification and regression trees (CART), and ensemble CART using bootstrapping. All of

  20. Relationships Between the Bulk-Skin Sea Surface Temperature Difference, Wind, and Net Air-Sea Heat Flux

    NASA Technical Reports Server (NTRS)

    Emery, William J.; Castro, Sandra L.; Lindstrom, Eric (Technical Monitor)

    2002-01-01

    The primary purpose of this project was to evaluate and improve models for the bulk-skin temperature difference to the point where they could accurately and reliably apply under a wide variety of environmental conditions. To accomplish this goal, work was conducted in three primary areas. These included production of an archive of available data sets containing measurements of the skin and bulk temperatures and associated environmental conditions, evaluation of existing skin layer models using the compiled data archive, and additional theoretical work on the development of an improved model using the data collected under diverse environmental conditions. In this work we set the basis for a new physical model of renewal type, and propose a parameterization for the temperature difference across the cool skin of the ocean in which the effects of thermal buoyancy, wind stress, and microscale breaking are all integrated by means of the appropriate renewal time scales. Ideally, we seek to obtain a model that will accurately apply under a wide variety of environmental conditions. A summary of the work in each of these areas is included in this report. A large amount of work was accomplished under the support of this grant. The grant supported the graduate studies of Sandra Castro and the preparation of her thesis which will be completed later this year. This work led to poster presentations at the 1999 American Geophysical Union Fall Meeting and 2000 IGARSS meeting. Additional work will be presented in a talk at this year's American Meteorological Society Air-Sea Interaction Meeting this May. The grant also supported Sandra Castro during a two week experiment aboard the R/P Flip (led by Dr. Andrew Jessup of the Applied Physics Laboratory) to help obtain additional shared data sets and to provide Sandra with a fundamental understanding of the physical processes needed in the models. In a related area, the funding also partially supported Dr. William Emery and Daniel

  1. Thermal Comfort: An Index for Hot, Humid Asia. Educational Building Digest 12.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and Oceania.

    The sensation of thermal comfort is determined by a combination of air temperature, humidity of the air, rate of movement of the air, and radiant heat. This digest is intended to assist architects to design educational facilities that are as thermally comfortable as is possible without recourse to mechanical air conditioning. A nomogram is…

  2. Gas and humidity sensing element

    SciTech Connect

    Komine, Y.; Sawada, T.

    1984-06-26

    A gas and humidity sensing element in a single integral structure made of a base plate of apatite ceramics, on which a particular metal oxide such as tin oxide, zinc oxide, or composite oxide of titanium and niobium is provided. The sensing element has a function of sensing gas and humidity with outstanding sensitivity to bad smell gas and alcoholic gas, in which the humidity is sensed and measured by variations in electrical resistance of the apatite ceramic base plate and the bad smell gas such as hydrogen sulfide, methyl mercaptan, etc. is sensed and measured by variations in electrical resistance of the metal oxide.

  3. Determining the Probability of Violating Upper-Level Wind Constraints for the Launch of Minuteman III Ballistic Missiles at Vandenberg Air Force Base

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.; Brock, Tyler M.

    2012-01-01

    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman Ill ballistic missile. The 30 OSSWF tasked the Applied Meteorology Unit (AMU) to analyze VAFB sounding data with the goal of determining the probability of violating (PoV) their upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a tool that will calculate the PoV of each constraint on the day of launch. In order to calculate the probability of exceeding each constraint, the AMU collected and analyzed historical data from VAFB. The historical sounding data were retrieved from the National Oceanic and Atmospheric Administration Earth System Research Laboratory archive for the years 1994-2011 and then stratified into four sub-seasons: January-March, April-June, July-September, and October-December. The AMU determined the theoretical distributions that best fit the maximum wind speed and maximum wind shear datasets and applied this information when calculating the averages and standard deviations needed for the historical and real-time PoV calculations. In addition, the AMU included forecast sounding data from the Rapid Refresh model. This information provides further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours on the day of launch. The AMU developed an interactive graphical user interface (GUI) in Microsoft Excel using Visual Basic for Applications. The GUI displays the critical sounding data easily and quickly for LWOs on day of launch. This tool will replace the existing one used by the 30 OSSWF, assist the LWOs in determining the probability of exceeding specific wind threshold values, and help to improve the overall upper winds forecast for

  4. Distortion of thermospheric air masses by horizontal neutral winds over Poker Flat Alaska measured using an all-sky scanning Doppler imager

    NASA Astrophysics Data System (ADS)

    Dhadly, M. S.; Conde, M.

    2016-01-01

    An air mass transported by a wind field will become distorted over time by any gradients present in the wind field. To study this effect in Earth's thermosphere, we examine the behavior of a simple parameter that we describe here as the "distortion gradient." It incorporates all of the wind field's departures from uniformity and is thus capable of representing all contributions to the distortion or mixing of air masses. The distortion gradient is defined such that it is always positive, so averaging over time and/or space does not suppress small-scale features. Conventional gradients, by contrast, are signed quantities that would often average to zero. To analyze the climatological behavior of this distortion gradient, we used three years (2010, 2011, and 2012) of thermospheric F region wind observations from a high-latitude ground-based all-sky wavelength scanning Doppler Fabry-Perot interferometer located at Poker Flat Alaska. Climatological averaging of the distortion gradient allowed us to investigate its diurnal and seasonal (annual) behaviors at our observing location. Distortion was observed to be higher before local magnetic midnight and to be seasonally dependent. While maximum distortion occurred before local magnetic midnight under all geomagnetic conditions, the peak distortion occurred earlier under moderate geomagnetic conditions as compared to the quiet geomagnetic conditions and even earlier still when geomagnetic conditions were active. Peak distortion was stronger and appeared earlier when interplanetary magnetic field (IMF) was southward compared to northward. By contrast, we could not resolve any time-shift effect due to the IMF component tangential to Earth's orbit.

  5. An investigation of drag reduction for tractor trailer vehicles with air deflector and boattail. [wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Muirhead, V. U.

    1981-01-01

    A wind tunnel investigation was conducted to determine the influence of several physical variables on the aerodynamic drag of a trailer model. The physical variables included: a cab mounted wind deflector, boattail on trailer, flow vanes on trailer front, forced transition on trailer, and decreased gap between tractor and trailer. Tests were conducted at yaw angles (relative wind angles) of 0, 5, 10, 20, and 30 degrees and Reynolds numbers of 3.58 x 10 to the 5th power 6.12 x 10 to the 5th power based upon the equivalent diameter of the vehicles. The wind deflector on top of the cab produced a calculated reduction in fuel consumption of about 5 percent of the aerodynamic portion of the fuel budget for a wind speed of 15.3 km/hr (9.5 mph) over a wind angle range of 0 deg to 180 deg and for a vehicle speed of 88.5 km/hr (55 mph). The boattail produced a calculated 7 percent to 8 percent reduction in fuel consumption under the same conditions. The decrease in gap reduced the calculated fuel consumption by about 5 percent of the aerodynamic portion of the fuel budget.

  6. Production cost and air emissions impacts of coal cycling in power systems with large-scale wind penetration

    NASA Astrophysics Data System (ADS)

    Oates, David Luke; Jaramillo, Paulina

    2013-06-01

    Wind power introduces variability into electric power systems. Due to the physical characteristics of wind, most of this variability occurs at inter-hour time-scales and coal units are therefore technically capable of balancing wind. Operators of coal-fired units have raised concerns that additional cycling will be prohibitively costly. Using PJM bid-data, we observe that coal operators are likely systematically under-bidding their startup costs. We then consider the effects of a 20% wind penetration scenario in the coal-heavy PJM West area, both when coal units bid business as usual startup costs, and when they bid costs accounting for the elevated wear and tear that occurs during cycling. We conclude that while 20% wind leads to increased coal cycling and reduced coal capacity factors under business as usual startup costs, including full startup costs shifts the burden of balancing wind onto more flexible units. This shift has benefits for CO2, NOX, and SO2 emissions as well as for the profitability of coal plants, as calculated by our dispatch model.

  7. Thermal Comfort in the Hot Humid Tropics of Australia

    PubMed Central

    Wyndham, C. H.

    1963-01-01

    Day and night comfort votes were recorded from Caucasian residents at Weipa, a mission station in the hot humid tropics of North Queensland, Australia. The limit of day comfort for more than 50% of the men was 81·5°F. (27·5°C.) “normal” corrected effective temperature; the night limit was 78·0°F. (25·5°C.). Day comfort limits correlated well with air conditions at which sweat was apparent: night limits correlated with the amount of bed covering. Evidence of a change over 14 days in day comfort limit was found. Limitations in the effective temperature scale for expressing the “oppressive nature” of night air conditions are pointed out. Criticism is voiced of the use of dry bulb temperature instead of the effective temperature scale in conditions of high wet bulb temperatures with high relative humidity, such as in the hot humid tropics. PMID:14002126

  8. Temperature, Humidity, And Polymer Aging

    NASA Technical Reports Server (NTRS)

    Cuddihy, Edward F.

    1988-01-01

    Report presents analysis of experimental data on electrical resistivity of polymer (polyvinyl butyral) as function of temperature and relative humidity. Resulting theoretical expression for electrical resistivity resembles generally accepted empirical law for the corrosion rate.

  9. Humidity testing of bleached holograms.

    PubMed

    Chenoweth, A J

    1971-04-01

    One of the proposed storage media for semipermanent optical stores is an array of bleached holograms fabricated on photographic plates. If a store utilizing this medium is to be operated in a field environment, the effect of humidity variation requires consideration. In this study holograms were made using either Burckhardt's potassium ferricyanide or Russo and Sottini's modified R-10 type bleach on Kodak 649F and Agfa 10E70 plates. Diffraction efficiency was measured as a function of relative humidity over the range 30-98%. For holograms fabricated and tested as described above it was found that relative humidity values above 75% caused a permanent loss in diffraction efficiency for potassium ferricyanide bleached plates; humidity above 90% produced a temporary loss in R-10 bleached plates. PMID:20094561

  10. Humidity sensing with doped polyaniline

    NASA Astrophysics Data System (ADS)

    Jain, Shilpa; Chakane, Sanjay D. S.; Bhoraskar, S. V.; Samui, A. B.; Krishnamurthy, V. N.

    2001-03-01

    Polyaniline (PANI) was doped with different dopants like camphosulphoric acid (CSA), diphenyl phosphate (DPPH), Sulphonic acid (S) and Maleic acid (MAC) by chemical method. The samples were prepared in the form of pellets as well as films. Polyaniline doped with Maleic acid was found to be mechanically and chemically stable as compared to other dopants and therefore the effect of humidity on conductivity was further investigated. Films prepared out of styrene buryl acrylate copolymer with different concentrations of PANI Maleic acid were used for sensing humidity ranging between 20% to 90% relative humidity. A maximum change in the conductivity of three to four orders of magnitude was obtained for the Maleic acid doped polyaniline pellet while two orders of magnitude change was obtained for the film samples over the range of humidity measured.

  11. Experimental investigation of the dependence of radar backscattering on wind speed, wind stress and wave height

    NASA Technical Reports Server (NTRS)

    Gogineni, S. P.; Katsaros, K. B.

    1989-01-01

    During summer 1988, radar measurements were performed in conjunction with detailed environmental observations on Lake Washington at the University of Washington Sand Point field station. Radar data were collected at 5.3 and 10 GHz for incidence angles between 30 and 60 deg with VV-polarization. The environmental measurements included wind speed and direction, large-wave heights, the high-frequency portion of the wave spectrum, humidity, and air and water temperatures. The small-scale wave spectrum was measured using a resistance wire gauge. The results show that backscatter increased with wind speed as expected. However, little difference was observed in the scattering coefficient for upwind and crosswind directions. The results also indicated an increase in the amplitude of small waves with friction velocity.

  12. Application of infrared radiometers for airborne detection of clear air turbulence and low level wind shear, airborne infrared low level wind shear detection test

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.

    1985-01-01

    The feasibility of infrared optical techniques for the advance detection and avoidance of low level wind shear (LLWS) or low altitude wind shear hazardous to aircraft operations was investigated. A primary feasibility research effort was conducted with infrared detectors and instrumentation aboard the NASA Ames Research Center Learjet. The main field effort was flown on the NASA-Ames Dryden B57B aircraft. The original approach visualized a forward-looking, infrared transmitting (KRS-5) window through which signals would reach the detector. The present concept of a one inch diameter light pipe with a 45 deg angled mirror enables a much simpler installation virtually anywhere on the aircraft coupled with the possibility of horizontal scanning via rotation of the forward directed mirror. Present infrared detectors and filters would certainly permit ranging and horizontal scanning in a variety of methods. CRT display technology could provide a contoured picture with possible shear intensity levels from the infrared detection system on the weather radar or a small adjunct display. This procedure shoud be further developed and pilot evaluated in a light aircraft such as a Cessna 207 or equivalent.

  13. Humidity profiles over the ocean

    NASA Technical Reports Server (NTRS)

    Liu, W. T.; Tang, Wenqing; Niiler, Pearn P.

    1991-01-01

    The variabilities of atmospheric humidity profile over oceans from daily to interannual time scales were examined using 9 years of daily and semidaily radiosonde soundings at island stations extending from the Arctic to the South Pacific. The relative humidity profiles were found to have considerable temporal and geographic variabilities, contrary to the prevalent assumption. Principal component analysis on the profiles of specific humidity were used to examine the applicability of a relation between the surface-level humidity and the integrated water vapor; this relation has been used to estimate large-scale evaporation from satellite data. The first principal component was found to correlate almost perfectly with the integrated water vapor. The fractional variance represented by this mode increases with increasing period. It reaches approximately 90 percent at two weeks and decreases sharply, below one week, down to approximately 60 percent at the daily period. At low frequencies, the integrated water vapor appeared to be an adequate estimator of the humidity profile and the surface-level humidity. At periods shorter than a week, more than one independent estimator is needed.

  14. Effects of Humidity on Solid Oxide Fuel Cell Cathodes

    SciTech Connect

    Hardy, John S.; Stevenson, Jeffry W.; Singh, Prabhakar; Mahapatra, Manoj K.; Wachsman, E. D.; Liu, Meilin; Gerdes, Kirk R.

    2015-03-17

    This report summarizes results from experimental studies performed by a team of researchers assembled on behalf of the Solid-state Energy Conversion Alliance (SECA) Core Technology Program. Team participants employed a variety of techniques to evaluate and mitigate the effects of humidity in solid oxide fuel cell (SOFC) cathode air streams on cathode chemistry, microstructure, and electrochemical performance.

  15. 40 CFR 86.344-79 - Humidity calculations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Humidity calculations. 86.344-79 Section 86.344-79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for New Gasoline-Fueled and...

  16. Comparison of a simple logarithmic and equivalent neutral wind approaches for converting buoy-measured wind speed to the standard height: special emphasis to North Indian Ocean

    NASA Astrophysics Data System (ADS)

    Singh, Prem; Parekh, Anant; Attada, Raju

    2013-02-01

    The difference between the transferred wind speed to 10-m height based on the equivalent neutral wind approach ( U n) and the logarithmic approach ( U log) is studied using in situ observations from the Indian, Pacific, and Atlantic Oceans, with special emphasis given to the North Indian Ocean. The study included U n - U log variations with pressure, relative humidity, wind speed, air temperature, and sea surface temperature (SST). U n - U log variation with respect to air temperature ( T a) reveals that U n - U log is out of phase with air temperature. Further analysis found that U n - U log is in phase with SST ( T s) - T a and varies between -1.0 and 1.0 m/s over the North Indian Ocean, while for the rest of the Oceans, it is between -0.3 and 0.8 m/s. This higher magnitude of U n - U log over the North Indian Ocean is due to the higher range of T s - T a (-4 to 6 °C) in the North Indian Ocean. Associated physical processes suggested that the roughness length and friction velocity dependence on the air-sea temperature difference contributes to the U n - U log difference. The study is further extended to evaluate the behavior of U n - U log under cyclonic conditions (winds between 15 and 30 m/s), and it was found that the magnitude of Un - U log varies 0.5-1.5 m/s under the cyclonic wind conditions. The increasing difference with the wind speed is due to the increase in the momentum transfer coefficient with wind speed, which modifies the friction velocity significantly, resulting in U n higher than U log. Thus, under higher wind conditions, U n - U log can contribute up to half the retrieval error (5 % of the wind speed magnitude) to the satellite validation exercise.

  17. Geometeorological data collected by the USGS Desert Winds Project at Desert Wells, Sonoran Desert, central-west Arizona, 1981 - 1996

    USGS Publications Warehouse

    Helm, Paula J.; Breed, Carol S.; Tigges, Richard; Creighton, Shawn

    1998-01-01

    The data in this report were obtained by instruments deployed on a GOES-satellite data collection station operated by the U.S. Geological Survey Desert Winds Project at Desert Wells (latitude 33° 42' 08" N, longitude 113° 48' 40" W), La Paz County, west-central Arizona. The elevation is 344 m (1,130 ft). From January 9, 1981 through May 31, 1995 the station recorded eight parameters: wind direction, wind speed, peak gust, air temperature, precipitation, humidity, barometric pressure, and soil temperature. On June 1, 1995, the station was upgraded by adding a SENSIT sand-flux sensor, which records grain impacts concurrently with wind speed and wind direction measurements. Included with the data is descriptive text on the geology, soils, climate, vegetation, and land use at the site, as well as text on data format, date retrieval software and instructions, and metadata

  18. Application for temperature and humidity monitoring of data center environment

    NASA Astrophysics Data System (ADS)

    Albert, Ş.; Truşcǎ, M. R. C.; Soran, M. L.

    2015-12-01

    The technology and computer science registered a large development in the last years. Most systems that use high technologies require special working conditions. The monitoring and the controlling are very important. The temperature and the humidity are important parameters in the operation of computer systems, industrial and research, maintaining it between certain values to ensure their proper functioning being important. Usually, the temperature is maintained in the established range using an air conditioning system, but the humidity is affected. In the present work we developed an application based on a board with own firmware called "AVR_NET_IO" using a microcontroller ATmega32 type for temperature and humidity monitoring in Data Center of INCDTIM. On this board, temperature sensors were connected to measure the temperature in different points of the Data Center and outside of this. Humidity monitoring is performed using data from integrated sensors of the air conditioning system, thus achieving a correlation between humidity and temperature variation. It was developed a software application (CM-1) together with the hardware, which allows temperature monitoring and register inside Data Center and trigger an alarm when variations are greater with 3°C than established limits of the temperature.

  19. Air gap winding method and support structure for a super conducting generator and method for forming the same

    DOEpatents

    Hopeck, James Frederick

    2003-11-25

    A method of forming a winding support structure for use with a superconducting rotor wherein the method comprises providing an inner support ring, arranging an outer support ring around the inner support ring, coupling first and second support blocks to the outer support ring and coupling a lamination to the first and second support blocks. A slot is defined between the support blocks and between the outer support ring and the lamination to receive a portion of a winding. An RTV fills any clearance space in the slot.

  20. Power augmentation in a Savonius-type wind-turbine by using a single air-deflecting vane

    NASA Astrophysics Data System (ADS)

    Sivapalan, S.; Sivasegaram, S.

    1982-07-01

    This paper deals with the increase of power output from a vertical-axis wind-turbine of the Savonius-type by using a single deflector vane of simple geometry. Vanes of plane and circular arc sections were used in the study. The respective influences of vane arc angle, vane size and angle of setting of the vane relative to the rotor on the power output were studied and so was the sensitivity of power output to wind direction. Power augmentation by over 50% is seen possible with a single vane of modest size. Means of further power augmentation and achievement of direction-independent operation are discussed.

  1. Trends and abrupt changes in 104 years of ice cover and water temperature in a dimictic lake in response to air temperature, wind speed, and water clarity drivers

    NASA Astrophysics Data System (ADS)

    Magee, Madeline R.; Wu, Chin H.; Robertson, Dale M.; Lathrop, Richard C.; Hamilton, David P.

    2016-05-01

    The one-dimensional hydrodynamic ice model, DYRESM-WQ-I, was modified to simulate ice cover and thermal structure of dimictic Lake Mendota, Wisconsin, USA, over a continuous 104-year period (1911-2014). The model results were then used to examine the drivers of changes in ice cover and water temperature, focusing on the responses to shifts in air temperature, wind speed, and water clarity at multiyear timescales. Observations of the drivers include a change in the trend of warming air temperatures from 0.081 °C per decade before 1981 to 0.334 °C per decade thereafter, as well as a shift in mean wind speed from 4.44 m s-1 before 1994 to 3.74 m s-1 thereafter. Observations show that Lake Mendota has experienced significant changes in ice cover: later ice-on date(9.0 days later per century), earlier ice-off date (12.3 days per century), decreasing ice cover duration (21.3 days per century), while model simulations indicate a change in maximum ice thickness (12.7 cm decrease per century). Model simulations also show changes in the lake thermal regime of earlier stratification onset (12.3 days per century), later fall turnover (14.6 days per century), longer stratification duration (26.8 days per century), and decreasing summer hypolimnetic temperatures (-1.4 °C per century). Correlation analysis of lake variables and driving variables revealed ice cover variables, stratification onset, epilimnetic temperature, and hypolimnetic temperature were most closely correlated with air temperature, whereas freeze-over water temperature, hypolimnetic heating, and fall turnover date were more closely correlated with wind speed. Each lake variable (i.e., ice-on and ice-off dates, ice cover duration, maximum ice thickness, freeze-over water temperature, stratification onset, fall turnover date, stratification duration, epilimnion temperature, hypolimnion temperature, and hypolimnetic heating) was averaged for the three periods (1911-1980, 1981-1993, and 1994-2014) delineated by

  2. Resistive graphene humidity sensors with rapid and direct electrical readout

    NASA Astrophysics Data System (ADS)

    Smith, Anderson D.; Elgammal, Karim; Niklaus, Frank; Delin, Anna; Fischer, Andreas C.; Vaziri, Sam; Forsberg, Fredrik; Råsander, Mikael; Hugosson, Håkan; Bergqvist, Lars; Schröder, Stephan; Kataria, Satender; Östling, Mikael; Lemme, Max C.

    2015-11-01

    We demonstrate humidity sensing using a change of the electrical resistance of single-layer chemical vapor deposited (CVD) graphene that is placed on top of a SiO2 layer on a Si wafer. To investigate the selectivity of the sensor towards the most common constituents in air, its signal response was characterized individually for water vapor (H2O), nitrogen (N2), oxygen (O2), and argon (Ar). In order to assess the humidity sensing effect for a range from 1% relative humidity (RH) to 96% RH, the devices were characterized both in a vacuum chamber and in a humidity chamber at atmospheric pressure. The measured response and recovery times of the graphene humidity sensors are on the order of several hundred milliseconds. Density functional theory simulations are employed to further investigate the sensitivity of the graphene devices towards water vapor. The interaction between the electrostatic dipole moment of the water and the impurity bands in the SiO2 substrate leads to electrostatic doping of the graphene layer. The proposed graphene sensor provides rapid response direct electrical readout and is compatible with back end of the line (BEOL) integration on top of CMOS-based integrated circuits.We demonstrate humidity sensing using a change of the electrical resistance of single-layer chemical vapor deposited (CVD) graphene that is placed on top of a SiO2 layer on a Si wafer. To investigate the selectivity of the sensor towards the most common constituents in air, its signal response was characterized individually for water vapor (H2O), nitrogen (N2), oxygen (O2), and argon (Ar). In order to assess the humidity sensing effect for a range from 1% relative humidity (RH) to 96% RH, the devices were characterized both in a vacuum chamber and in a humidity chamber at atmospheric pressure. The measured response and recovery times of the graphene humidity sensors are on the order of several hundred milliseconds. Density functional theory simulations are employed to further

  3. Study of field-pole Bi2223 windings of air core type for a HTS propulsion motor

    NASA Astrophysics Data System (ADS)

    Sugyo, D.; Kimura, Y.; Sano, T.; Yamaguchi, K.; Izumi, M.; Miki, M.; Ohmatu, K.; Fukumoto, Y.; Fujimoto, H.

    2008-02-01

    In the present study, we designed a field pole of Bi2223 superconductor winding without iron core applied to high-temperature superconducting (HTS) motor of an axial gap type. As the preliminary step to form a field pole winding, we designed a double-pancake-coil (DPC) and qualified relationship between the terminal voltage and the excitation current. We adopted the structure of HTS winding field pole composed of stacked two layered DPC because of effective conduction cooling and electromagnetic effect. We manufactured 16 poles DPC and verified the critical current vs. terminal voltage at 77 K with liquid nitrogen. To form a rotor, 8 field-pole HTS windings were manufactured by integrating of two DPCs as a split coil. We measured the coil Ic and voltage drop of the terminal at 30 K cooled with gas-liquid mixing helium and qualified the heat generation from the coils with DC current excitation. The cooling and excitation test of the constructed field pole coils were performed in the testing motor. The results exhibit that presently developed coils possesses sufficient performance on the heat generation and the magnetic flux density in the axial-type machine under construction.

  4. Incorporating the Wind Erosion Prediction System (WEPS) Into a Regional Air Quality Modeling System for the Pacific Northwest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Pacific Northwest, wind storms intermittently cause massive dust events that reduce visibility along roadways and jeopardize health as a result of extremely high concentrations of PM10 (particulate matter less than or equal to 10µm in diameter). An early warning dust forecast system is needed...

  5. Ice core evidence of rapid air temperature increases since 1960 in alpine areas of the Wind River Range, Wyoming, United States

    USGS Publications Warehouse

    Naftz, D.L.; Susong, D.D.; Schuster, P.F.; Cecil, L.D.; Dettinger, M.D.; Michel, R.L.; Kendall, C.

    2002-01-01

    Site-specific transfer functions relating delta oxygen 18 (??18O) values in snow to the average air temperature (TA) during storms on Upper Fremont Glacier (UFG) were used in conjunction with ??18O records from UFG ice cores to reconstruct long-term trends in air temperature from alpine areas in the Wind River Range, Wyoming. Transfer functions were determined by using data collected from four seasonal snowpacks (1989-1990, 1997-1998, 1998-1999, and 1999-2000). The timing and amount of each storm was determined from an automated snowpack telemetry (SNOTEL) site, 22 km northeast of UFG, and ???1060 m in elevation below UFG. Statistically significant and positive correlations between ??18O values in the snow and TA were consistently found in three of the four seasonal snowpacks. The snowpack with the poor correlation was deposited in 1997-1998 during the 1997-1998 El Nin??o Southern Oscillation (ENSO). An ultrasonic snow-depth sensor installed on UFG provided valuable insights into site-specific storms and postdepositional processes that occur on UFG. The timing of storms recorded at the UFG and Cold Springs SNOTEL sites were similar; however, selected storms did not correlate. Snow from storms occurring after mid-October and followed by high winds was most susceptible to redeposition of snow. This removal of lower temperature snowfall could potentially bias the ??18O values preserved in ice core records to environmental conditions reflecting higher air temperatures and lower wind speeds. Transfer functions derived from seasonal snow cover on UFG were used to reconstruct TA values from ??18O values determined from two ice cores collected from UFG. Reconstructed air temperatures from the ice core data indicate an increase in TA of ???3.5??C from the mid-1960s to the early 1990s in the alpine areas of northwestern Wyoming. Reconstructed TA from the ice core records between the end of the Little Ice Age (LIA), mid-1800s, and the early 1990s indicate a TA increase of

  6. Greenhouse gas and air pollutant emission reduction potentials of renewable energy - case studies on photovoltaic and wind power introduction considering interactions among technologies in Taiwan

    SciTech Connect

    Yu-Ming Kuo; Yasuhiro Fukushima

    2009-03-15

    To achieve higher energy security and lower emission of greenhouse gases (GHGs) and pollutants, the development of renewable energy has attracted much attention in Taiwan. In addition to its contribution to the enhancement of reliable indigenous resources, the introduction of renewable energy such as photovoltaic (PV) and wind power systems reduces the emission of GHGs and air pollutants by substituting a part of the carbon- and pollutant-intensive power with power generated by methods that are cleaner and less carbon-intensive. To evaluate the reduction potentials, consequential changes in the operation of different types of existing power plants have to be taken into account. In this study, a linear mathematical programming model is constructed to simulate a power mix for a given power demand in a power market sharing a cost-minimization objective. By applying the model, the emission reduction potentials of capacity extension case studies, including the enhancement of PV and wind power introduction at different scales, were assessed. In particular, the consequences of power mix changes in carbon dioxide, nitrogen oxides, sulfur oxides, and particulates were discussed. Seasonally varying power demand levels, solar irradiation, and wind strength were taken into account. In this study, we have found that the synergetic reduction of carbon dioxide emission induced by PV and wind power introduction occurs under a certain level of additional installed capacity. Investigation of a greater variety of case studies on scenario development with emerging power sources becomes possible by applying the model developed in this study. 15 refs., 8 figs., 11 tabs.

  7. Effect of humidity on fretting wear of several pure metals

    NASA Technical Reports Server (NTRS)

    Goto, H.; Buckley, D. H.

    1984-01-01

    Fretting wear experiments with several pure metals were conducted in air at various relative humidity levels. The materials used were iron, aluminum, copper, silver, chromium, titanium, and nickel. Each pure metal had a maximum fretting wear volume at a specific humidity level RH sub max that was not dependent on mechanical factors such as contact load, fretting amplitude, and frequency in the ranges studied. The weight loss due to fretting wear at RH sub max for each pure metal decreased with increasing heat of oxygen adsorption on the metal, indicating that adhesive wear dominated at RH sub max.

  8. Challenges to Cabin Humidity Removal Presented by Intermittent Condensing Conditions

    NASA Technical Reports Server (NTRS)

    vonJouanne, Roger G.; Williams, David E.

    2007-01-01

    On-orbit temperature and humidity control (THC) is more easily accomplished when the THC hardware is either consistently dry (i.e., no humidity control is occurring), or consistently wet. The system is especially challenged when intermittent wet/dry conditions occur. The first six years of on-orbit ISS operations have revealed specific concerns within the THC system, specifically in the condensing heat exchanger and the downstream air/water separator. Failed or degraded hardware has been returned to ground and investigated. This paper presents the investigation findings, and the recommended hardware and procedural revisions to prevent and recover from the effects of intermittent condensing conditions.

  9. Ultrahigh humidity sensitivity of graphene oxide

    PubMed Central

    Bi, Hengchang; Yin, Kuibo; Xie, Xiao; Ji, Jing; Wan, Shu; Sun, Litao; Terrones, Mauricio; Dresselhaus, Mildred S.

    2013-01-01

    Humidity sensors have been extensively used in various fields, and numerous problems are encountered when using humidity sensors, including low sensitivity, long response and recovery times, and narrow humidity detection ranges. Using graphene oxide (G-O) films as humidity sensing materials, we fabricate here a microscale capacitive humidity sensor. Compared with conventional capacitive humidity sensors, the G-O based humidity sensor has a sensitivity of up to 37800% which is more than 10 times higher than that of the best one among conventional sensors at 15%–95% relative humidity. Moreover, our humidity sensor shows a fast response time (less than 1/4 of that of the conventional one) and recovery time (less than 1/2 of that of the conventional one). Therefore, G-O appears to be an ideal material for constructing humidity sensors with ultrahigh sensitivity for widespread applications. PMID:24048093

  10. Repair of Corrosion in Air Supply Piping at the NASA Glenn Research Center's 1 by 1 Foot Supersonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Henry, Michael

    2000-01-01

    During a test at the NASA Glenn Research Center's 1 x 1 Supersonic Wing Tunnel, it was discovered that particles entrained in the air flow were damaging the pressure sensitive paint on a test article. An investigation found the source of the entrained particles to be rust on the internal surfaces of the air supply piping. To remedy the situation, the air supply line components made from carbon steel were either refurbished or replaced with new stainless steel components. The refurbishment process included various combinations of chemical cleaning, bead blasting, painting and plating.

  11. Photogated humidity-driven motility

    NASA Astrophysics Data System (ADS)

    Zhang, Lidong; Liang, Haoran; Jacob, Jolly; Naumov, Panče

    2015-06-01

    Hygroinduced motion is a fundamental process of energy conversion that is essential for applications that require contactless actuation in response to the day-night rhythm of atmospheric humidity. Here we demonstrate that mechanical bistability caused by rapid and anisotropic adsorption and desorption of water vapour by a flexible dynamic element that harnesses the chemical potential across very small humidity gradients for perpetual motion can be effectively modulated with light. A mechanically robust material capable of rapid exchange of water with the surroundings is prepared that undergoes swift locomotion in effect to periodic shape reconfiguration with turnover frequency of <150 min-1. The element can lift objects ~85 times heavier and can transport cargos ~20 times heavier than itself. Having an azobenzene-containing conjugate as a photoactive dopant, this entirely humidity-driven self-actuation can be controlled remotely with ultraviolet light, thus setting a platform for next-generation smart biomimetic hybrids.

  12. Photogated humidity-driven motility

    PubMed Central

    Zhang, Lidong; Liang, Haoran; Jacob, Jolly; Naumov, Panče

    2015-01-01

    Hygroinduced motion is a fundamental process of energy conversion that is essential for applications that require contactless actuation in response to the day–night rhythm of atmospheric humidity. Here we demonstrate that mechanical bistability caused by rapid and anisotropic adsorption and desorption of water vapour by a flexible dynamic element that harnesses the chemical potential across very small humidity gradients for perpetual motion can be effectively modulated with light. A mechanically robust material capable of rapid exchange of water with the surroundings is prepared that undergoes swift locomotion in effect to periodic shape reconfiguration with turnover frequency of <150 min−1. The element can lift objects ∼85 times heavier and can transport cargos ∼20 times heavier than itself. Having an azobenzene-containing conjugate as a photoactive dopant, this entirely humidity-driven self-actuation can be controlled remotely with ultraviolet light, thus setting a platform for next-generation smart biomimetic hybrids. PMID:26067649

  13. Short term change in relative humidity during the festival of Diwali in India

    NASA Astrophysics Data System (ADS)

    Ganguly, Nandita D.

    2015-07-01

    The changes in humidity levels during the Diwali festivities have been examined over a period of 13 years at three Indian metro cities: Ahmedabad, New Delhi and Kolkata. A small short term increase in relative humidity even in the absence of transport of humid air from Arabian Sea and Bay of Bengal has been observed. The relative humidity levels were found to be exceeding the ambient levels during night and lying below the ambient levels during morning hours, indicating an increase in the survival rates of viruses responsible for the transmission of viral infections, as well as triggering immune-mediated illnesses such as asthma during Diwali.

  14. Retrofit device and method to improve humidity control of vapor compression cooling systems

    DOEpatents

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2016-08-16

    A method and device for improving moisture removal capacity of a vapor compression system is disclosed. The vapor compression system is started up with the evaporator blower initially set to a high speed. A relative humidity in a return air stream is measured with the evaporator blower operating at the high speed. If the measured humidity is above the predetermined high relative humidity value, the evaporator blower speed is reduced from the initially set high speed to the lowest possible speed. The device is a control board connected with the blower and uses a predetermined change in measured relative humidity to control the blower motor speed.

  15. Hourly Wind Speed Interval Prediction in Arid Regions

    NASA Astrophysics Data System (ADS)

    Chaouch, M.; Ouarda, T.

    2013-12-01

    The long and extended warm and dry summers, the low rate of rain and humidity are the main factors that explain the increase of electricity consumption in hot arid regions. In such regions, the ventilating and air-conditioning installations, that are typically the most energy-intensive among energy consumption activities, are essential for securing healthy, safe and suitable indoor thermal conditions for building occupants and stored materials. The use of renewable energy resources such as solar and wind represents one of the most relevant solutions to overcome the increase of the electricity demand challenge. In the recent years, wind energy is gaining more importance among the researchers worldwide. Wind energy is intermittent in nature and hence the power system scheduling and dynamic control of wind turbine requires an estimate of wind energy. Accurate forecast of wind speed is a challenging task for the wind energy research field. In fact, due to the large variability of wind speed caused by the unpredictable and dynamic nature of the earth's atmosphere, there are many fluctuations in wind power production. This inherent variability of wind speed is the main cause of the uncertainty observed in wind power generation. Furthermore, producing wind power forecasts might be obtained indirectly by modeling the wind speed series and then transforming the forecasts through a power curve. Wind speed forecasting techniques have received substantial attention recently and several models have been developed. Basically two main approaches have been proposed in the literature: (1) physical models such as Numerical Weather Forecast and (2) statistical models such as Autoregressive integrated moving average (ARIMA) models, Neural Networks. While the initial focus in the literature has been on point forecasts, the need to quantify forecast uncertainty and communicate the risk of extreme ramp events has led to an interest in producing probabilistic forecasts. In short term

  16. Ultrafast graphene oxide humidity sensors.

    PubMed

    Borini, Stefano; White, Richard; Wei, Di; Astley, Michael; Haque, Samiul; Spigone, Elisabetta; Harris, Nadine; Kivioja, Jani; Ryhänen, Tapani

    2013-12-23

    Sensors allow an electronic device to become a gateway between the digital and physical worlds, and sensor materials with unprecedented performance can create new applications and new avenues for user interaction. Graphene oxide can be exploited in humidity and temperature sensors with a number of convenient features such as flexibility, transparency and suitability for large-scale manufacturing. Here we show that the two-dimensional nature of graphene oxide and its superpermeability to water combine to enable humidity sensors with unprecedented response speed (∼30 ms response and recovery times). This opens the door to various applications, such as touchless user interfaces, which we demonstrate with a 'whistling' recognition analysis. PMID:24206232

  17. Humidity Testing for Human Rated Spacecraft

    NASA Technical Reports Server (NTRS)

    Johnson, Gary B.

    2009-01-01

    Determination that equipment can operate in and survive exposure to the humidity environments unique to human rated spacecraft presents widely varying challenges. Equipment may need to operate in habitable volumes where the atmosphere contains perspiration, exhalation, and residual moisture. Equipment located outside the pressurized volumes may be exposed to repetitive diurnal cycles that may result in moisture absorption and/or condensation. Equipment may be thermally affected by conduction to coldplate or structure, by forced or ambient air convection (hot/cold or wet/dry), or by radiation to space through windows or hatches. The equipment s on/off state also contributes to the equipment s susceptibility to humidity. Like-equipment is sometimes used in more than one location and under varying operational modes. Due to these challenges, developing a test scenario that bounds all physical, environmental and operational modes for both pressurized and unpressurized volumes requires an integrated assessment to determine the "worst-case combined conditions." Such an assessment was performed for the Constellation program, considering all of the aforementioned variables; and a test profile was developed based on approximately 300 variable combinations. The test profile has been vetted by several subject matter experts and partially validated by testing. Final testing to determine the efficacy of the test profile on actual space hardware is in the planning stages. When validation is completed, the test profile will be formally incorporated into NASA document CxP 30036, "Constellation Environmental Qualification and Acceptance Testing Requirements (CEQATR)."

  18. 40 CFR 86.344-79 - Humidity calculations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 4101.12 4124.83 4148.65 4172.59 4196.66 4220.84 30 4245.15 4269.58 4294.13 4318.80 4343.60 4368.52 4393... = barometric pressure (Pa) H = specific humidity, (gm H2O/gm of dry air) K = 0.6220 gm H2O/gm dry air M air... = Web-bulb temperature (°K) B = − 12.150799 F 0 = − 8.49922(10)3 F 1 = − 7.4231865(10)3 F 2 =...

  19. 40 CFR 86.344-79 - Humidity calculations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 4101.12 4124.83 4148.65 4172.59 4196.66 4220.84 30 4245.15 4269.58 4294.13 4318.80 4343.60 4368.52 4393... = barometric pressure (Pa) H = specific humidity, (gm H2O/gm of dry air) K = 0.6220 gm H2O/gm dry air M air... = Web-bulb temperature (°K) B = − 12.150799 F 0 = − 8.49922(10)3 F 1 = − 7.4231865(10)3 F 2 =...

  20. The Chilled-Mirror Humidity Sensor: Improved Radiosonde Measurements

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.

    1999-01-01

    Chilled-mirror humidity sensor technology recently was adapted for use with the VIZ radiosonde. The principle of the chilled-mirror operation is to lower its temperature until dew forms on the mirror, at that point the dew point temperature is noted and the mirror is then heated to evaporate the moisture. The cycle is repeated. Research conducted from NASA's Wallops Flight Facility has provided comparisons between the chilled-mirror sensor and the carbon hygristor of VIZ, and the capacitive sensors of AIR Inc. and Vaisala Co. We believe the chilled-mirror sensor is accurate and would serve as a reference standard for evaluating operational radiosonde relative humidity sensors. Thus, differences seen in the comparisons are beginning to furnish insight into developing better humidity sensors. We discuss these comparison results as well as reproducibility results from a dual chilled-mirror measurement.

  1. Relative humidity from psychrometric data

    NASA Technical Reports Server (NTRS)

    Putnam, T. W.

    1976-01-01

    Analytical equation for computing relative humidity as function of wet bulb temperature, dry bulb temperature, and atmospheric pressure is suitable for use with calculator or computer. Analytical expressions may be useful for chemical process control systems and building environmental control systems.

  2. No-reheat air-conditioning

    NASA Technical Reports Server (NTRS)

    Obler, H. D.

    1980-01-01

    Air conditioning system, for environmentally controlled areas containing sensitive equipment, regulates temperature and humidity without wasteful and costly reheating. System blends outside air with return air as dictated by various sensors to ensure required humidity in cooled spaces (such as computer room).

  3. Apparatus for investigating the reactions of soft-bodied invertebrates to controlled humidity gradients

    PubMed Central

    Russell, Joshua; Pierce-Shimomura, Jonathan T.

    2015-01-01

    Background While many studies have assayed behavioral responses of animals to chemical, temperature and light gradients, fewer studies have assayed how animals respond to humidity gradients. Our novel humidity chamber has allowed us to study the neuromolecular basis of humidity sensation in the nematode Caenorhabditis elegans (Russell et al. 2014). New Method We describe an easy-to-construct, low-cost humidity chamber to assay the behavior of small animals, including soft-bodied invertebrates, in controlled humidity gradients. Results We show that our humidity-chamber design is amenable to soft-bodied invertebrates and can produce reliable gradients ranging 0.3–8% RH/cm across a 9-cm long x 7.5-cm wide gel-covered arena. Comparison with Existing Method(s) Previous humidity chambers relied on circulating dry and moist air to produce a steep humidity gradient in a small arena (e.g. Sayeed & Benzer, 1996). To remove the confound of moving air that may elicit mechanical responses independent of humidity responses, our chamber controlled the humidity gradient using reservoirs of hygroscopic materials. Additionally, to better observe the behavioral mechanisms for humidity responses, our chamber provided a larger arena. Although similar chambers have been described previously, these approaches were not suitable for soft-bodied invertebrates or for easy imaging of behavior because they required that animals move across wire or fabric mesh. Conclusion The general applicability of our humidity chamber overcomes limitations of previous designs and opens the door to observe the behavioral responses of soft-bodied invertebrates, including genetically powerful C. elegans and Drosophila larvae. PMID:25176025

  4. APPLICATION OF FOURIER TRANSFORM SPECTROSCOPY TO AIR POLLUTION PROBLEMS. COMPUTER-GENERATED LONG-PATH AIR SPECTRA

    EPA Science Inventory

    An atlas of computer-generated infrared transmission spectra of the atmosphere for low humidity (29 percent relative humidity) and high humidity (65 percent relative humidity) air samples is presented. These spectra extend from 700/cm to 3000/cm, and were computed with a resoluti...

  5. Influence of fine water droplets to temperature and humidity

    NASA Astrophysics Data System (ADS)

    Hafidzal, M. H. M.; Hamzah, A.; Manaf, M. Z. A.; Saadun, M. N. A.; Zakaria, M. S.; Roslizar, A.; Jumaidin, R.

    2015-05-01

    Excessively dry air can cause dry skin, dry eyes and exacerbation of medical conditions. Therefore, many researches have been done in order to increase humidity in our environment. One of the ways is by using water droplets. Nowadays, it is well known in market stand fan equipped with water mister in order to increase the humidity of certain area. In this study, the same concept is applied to the ceiling fan. This study uses a model that combines a humidifier which functions as cooler, ceiling fan and scaled down model of house. The objective of this study is to analyze the influence of ceiling fan humidifier to the temperature and humidity in a house. The mechanism of this small model uses batteries as the power source, connected to the fan and the humidifier. The small water tank's function is to store and supply water to the humidifier. The humidifier is used to cool the room by changing water phase to fine water droplets. Fine water droplets are created from mechanism of the humidifier, which is by increasing the kinetic energy of water molecule using high frequency vibration that overcome the holding force between water molecules. Thus, the molecule of water will change to state of gas or mist. The fan is used to spread out the mist of water to surrounding of the room in order to enhance the humidity. Thermocouple and humidity meter are used to measure temperature and humidity in some period of times. The result shows that humidity increases and temperature decreases with time. This application of water droplet can be applied in the vehicles and engine in order to decrease the temperature.

  6. Variation of elastic moduli of clays with humidity

    NASA Astrophysics Data System (ADS)

    Kuila, U.; Prasad, M.

    2012-12-01

    The elastic moduli of clays are highly variable. The reported values of elastic moduli of clays in the literature provide a large range: ranging from 0.15 GPa to 400 GPa. One of the many probable reasons for this variation is different external experimental environments leading to varied amounts of cations and bound water in the interlayers. The clay structure is affected by the kind of water associated with it: free water and bound water, the water in the interlayer. Smectite and mixed-layered illite-smectite (I-S) are capable of retaining significant electrostatic bound water in excess of 200C and can rapidly adsorb moisture from the air depending upon the humidity conditions. These can lead to the variation in their elastic properties. Prior experimental studies of acoustic velocity measurement in compacted clay pellets showed comparable trends (Figure 1) but different velocities for same reported porosity. This can be attributed to the humidity difference in the lab ambient conditions where the measurements were made. Molecular simulation studies on montmorillonite clays shows similar dependence of Young's Modulus on the hydration state of the clays (Pal Bathija 2009). In this paper, we studied the effect of humidity on the elastic properties of compacted pellets of Na-montmorillonite. This can be achieved by placing the Na-montmorillonite pellets in bell jars containing different saturated salt solutions. These salt solutions are used as a standard for relative humidity measurements. Figure 2 shows an experimental set-up used to the experiment. We will present the results of the variation of elastic properties of clays with varying humidity conditions. Preliminary results suggest that acoustic velocities through the compacted Na-montmorillonite pellet depend on the humidity conditions. The varying amount of interlayer clay-bound water and capillary condensation of water in small micropores in clays with varying humidity conditions resulted in the change in the

  7. Decomposition of nitric oxide in a hot nitrogen stream to synthesize air for hypersonic wind tunnel combustion testing

    NASA Technical Reports Server (NTRS)

    Zumdieck, J. F.; Zlatarich, S. A.

    1974-01-01

    A clean source of high enthalpy air was obtained from the exothermic decomposition of nitric oxide in the presence of strongly heated nitrogen. A nitric oxide jet was introduced into a confined coaxial nitrogen stream. Measurements were made of the extent of mixing and reaction. Experimental results are compared with one- and two-dimensional chemical kinetics computations. Both analyses predict much lower reactivity than was observed experimentally. Inlet nitrogen temperatures above 2400 K were sufficient to produce experimentally a completely reacted gas stream of synthetic air.

  8. On the Opposing Roles of Air Temperature and Wind Speed Variability in Flux Estimation over Partially Vegetated Landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In semi-arid regions the evapotranspiration rates depend on both the spatial distribution of the vegetation and the soil moisture, for a given radiation regime. Remote sensing can provide high resolution spatially distributed estimation of land surface states. However, data on the near surface air p...

  9. Stable and Selective Humidity Sensing Using Stacked Black Phosphorus Flakes.

    PubMed

    Yasaei, Poya; Behranginia, Amirhossein; Foroozan, Tara; Asadi, Mohammad; Kim, Kibum; Khalili-Araghi, Fatemeh; Salehi-Khojin, Amin

    2015-10-27

    Black phosphorus (BP) atomic layers are known to undergo chemical degradation in humid air. Yet in more robust configurations such as films, composites, and embedded structures, BP can potentially be utilized in a large number of practical applications. In this study, we explored the sensing characteristics of BP films and observed an ultrasensitive and selective response toward humid air with a trace-level detection capability and a very minor drift over time. Our experiments show that the drain current of the BP sensor increases by ∼4 orders of magnitude as the relative humidity (RH) varies from 10% to 85%, which ranks it among the highest ever reported values for humidity detection. The mechanistic studies indicate that the operation principle of the BP film sensors is based on the modulation in the leakage ionic current caused by autoionization of water molecules and ionic solvation of the phosphorus oxoacids produced on moist BP surfaces. Our stability tests reveal that the response of the BP film sensors remains nearly unchanged after prolonged exposures (up to 3 months) to ambient conditions. This study opens up the route for utilizing BP stacked films in many potential applications such as energy generation/storage systems, electrocatalysis, and chemical/biosensing. PMID:26401950

  10. Isokinetic air sampler

    DOEpatents

    Sehmel, George A.

    1979-01-01

    An isokinetic air sampler includes a filter, a holder for the filter, an air pump for drawing air through the filter at a fixed, predetermined rate, an inlet assembly for the sampler having an inlet opening therein of a size such that isokinetic air sampling is obtained at a particular wind speed, a closure for the inlet opening and means for simultaneously opening the closure and turning on the air pump when the wind speed is such that isokinetic air sampling is obtained. A system incorporating a plurality of such samplers provided with air pumps set to draw air through the filter at the same fixed, predetermined rate and having different inlet opening sizes for use at different wind speeds is included within the ambit of the present invention as is a method of sampling air to measure airborne concentrations of particulate pollutants as a function of wind speed.

  11. Humidity sensing by carbon nanocones.

    PubMed

    Svåsand, Eldrid; Häberle, Patricio

    2014-05-01

    Carbon nano-structures, mainly nanotubes, have been explored in the past as sensing devices. In this report we have considered cones and discs (CNCs) subjected to acid treatment, dry oxidation and high temperature annealing, to study the modifications induced as they are used as sensing elements of varying relative humidity (RH). The relative humidity was varied in cycles of 30 min between 36% and 75%. Not strangely, the acid treated films displayed a much larger variation in resistance for the same difference in RH (16%). In the as-grown material, very small variations were detected among cycles under similar conditions. The changes induced in the sensors structures by the different preparation procedures were characterized by transmission electron microscopy (TEM) and Raman reflexion. These results were used to model their behaviour as RH sensors. PMID:24734591

  12. Winter weather conditions vs. air quality in Tricity, Poland

    NASA Astrophysics Data System (ADS)

    Nidzgorska-Lencewicz, Jadwiga; Czarnecka, Małgorzata

    2015-02-01

    The principal aim of this paper is to assess the influence of meteorological conditions on the variability of sulfur dioxide and PM10 particulate matter concentration of pollutants during winter with consideration of an excess of admissible standards. The basis for the analysis were hourly concentrations of PM10 and sulfur dioxide as well as the basic meteorological elements automatically recorded at five stations located in the Tricity agglomeration, and operating within the weather station network belonging to the Agency of Regional Air Quality Monitoring in the Gdańsk Metropolitan Area (ARMAAG). The analysis covers the calendar winters (December-February) in the years 2004/2005 through 2009/2010. The variability of the concentrations of both pollutants under certain weather conditions, i.e. air temperature and relative humidity, atmospheric pressure, as well as wind speed and direction, were evaluated by means of cluster analysis using k-means belonging to a group of non-hierarchical cluster analysis method. The composite effect of meteorological conditions on the variability of sulfur dioxide and PM10 concentrations in isolated clusters were determined by multiple linear regression, using a stepwise procedure, at the significance level α = 0.05 and α = 0.01. The effect of individual weather elements on the pattern of concentration levels was determined using partial regression coefficients. Clusters grouping the highest concentrations of pollutants were characterised, in most cases, by the lowest air temperature and a lower wind speed, and often a higher pressure, and sometimes slightly lower relative air humidity, i.e. the conditions of anticyclonic weather. Weather conditions had a statistically significant effect on the concentrations of both pollutants in all clusters; however, air temperature and wind speed had the crucial role. Thermal conditions were the decisive factor in the winter season 2005/2006 with the most frequent, overnormative daily

  13. Humidity and Buildings. Technical Paper No. 188.

    ERIC Educational Resources Information Center

    Hutcheon, N. B.

    Modified and controlled relative humidity in buildings for certain occupancies is discussed. New criteria are used in determining the needs, desirability and problems associated with humidities in a building. Severe winter climate requires that special attention be given to the problems associated with increased indoor humidities during cold…

  14. Impact of fine particulate fluctuation and other variables on Beijing's air quality index.

    PubMed

    Chen, Bo; Lu, Shaowei; Li, Shaoning; Wang, Bing

    2015-04-01

    We analyzed fluctuation in Beijing's air quality over 328 days, based on air quality grades and air quality data from 35 atmospheric monitoring stations. Our results show the air over Beijing is subject to pollution 152 days of the year, or 46.34%. Among all pollutants, fine particulates, solid or liquid, 2.5 μm or less in size (PM2.5), appeared most frequently as the primary pollutant: 249 days, or 76% of the sample year (328 days). Nitrogen dioxide (NO2) and coarse particulates (PM10) cause the least pollution, appearing only 7 and 3 days, or 2 and 1% of the sample year, respectively. In Beijing, fine particulates like PM2.5 vary seasonally: 154.54 ± 18.60 in winter > 145.22 ± 18.61 in spring > 140.16 ± 20.76 in autumn > 122.37 ± 13.42 in summer. Air quality is best in August and worst in December, while various districts in Beijing experience different air quality. To be specific, from south to north and from west to east, air quality tends to improve. Meteorological elements have a constraining effect on air pollutants, which means there is a linear correlation between the air quality index and humidity, rainfall, wind speed, and temperature. Under a typical pollution scenario, the higher the air quality index (AQI) value, the lower the wind speed and the greater the relative humidity; the lower the AQI value, the higher the wind speed and lower the relative humidity. Analysis of influencing factors reveals that the air pollution is mainly particulate matter produced by burning coal, vehicle emissions, volatile oils and gas, fast development of food services, emissions from the surrounding region, and natural dust clouds formed in arid areas to the northwest. Topography affects the distribution of meteorological conditions, in turn varying air quality over the region from one location to another. Human activities also exercise impact on urban air quality with dual functions. PMID:25563832

  15. Windowless ultrasound photoacoustic cell for in vivo mid-IR spectroscopy of human epidermis: Low interference by changes of air pressure, temperature, and humidity caused by skin contact opens the possibility for a non-invasive monitoring of glucose in the interstitial fluid

    NASA Astrophysics Data System (ADS)

    Pleitez, Miguel A.; Lieblein, Tobias; Bauer, Alexander; Hertzberg, Otto; von Lilienfeld-Toal, Hermann; Mäntele, Werner

    2013-08-01

    The application of a novel open, windowless cell for the photoacoustic infrared spectroscopy of human skin is described. This windowless cavity is tuned for optimum performance in the ultrasound range between 50 and 60 kHz. In combination with an external cavity tunable quantum cascade laser emitting in the range from ˜1000 cm-1 to 1245 cm-1, this approach leads to high signal-to-noise-ratio (SNR) for mid-infrared spectra of human skin. This opens the possibility to measure in situ the absorption spectrum of human epidermis in the mid-infrared region at high SNR in a few (˜5) seconds. Rapid measurement of skin spectra greatly reduces artifacts arising from movements. As compared to closed resonance cells, the windowless cell exhibits the advantage that the influence of air pressure variations, temperature changes, and air humidity buildup that are caused by the contact of the cell to the skin surface can be minimized. We demonstrate here that this approach can be used for continuous and non-invasive monitoring of the glucose level in human epidermis, and thus may form the basis for a non-invasive monitoring of the glucose level for diabetes patients.

  16. Relative humidities in mid-latitude contrails

    NASA Astrophysics Data System (ADS)

    Krämer, M.; Kübbeler, M.; Meyer, J.; Schiller, C.; Gayet, J.-F.; Fiebig, M.; Hamburger, Th.; Petzold, A. Minikin (4), A.; Schlager, H.; Voigt, Ch.

    2009-04-01

    Aircraft contrails frequently occur in the upper troposphere. They consist of ice particles having the potential to directly affect the Earth's climate. The frequency, life time, ice crystal size spectra and thus radiative properties of contrails depend strongly on the ambient distribution of the relative humidity with respect to ice (RHi). In air with RHi below 100% contrails are believed to be short-lived, while persistent contrails require an ambient RHi of at least 100% (Gao et al., 2006, Atmospheric Environment). During the mid-latitude aircraft experiments CONCERT 2008 (CONtrail and Cirrus ExpeRimenT, 6 flights), CIRRUS 2006 (1 flight) and PAZI 2003 ('PArtikel und ZIrren', 2 flights), RHi inside of contrails were measured using the high precision Fast In-situ Stratospheric lyman-alpha Hygrometer FISH. We present results from about 1 hour of observation time in 52 contrails during the 9 flights. The peak of the RHi frequency distribution is around 90%, i.e. most of the contrails are observed in subsaturated air. There is indication that the age of the contrails is much larger than expected, implying that, to date, the lifetime of contrails below 100% RHi is underestimated. Further analysis of the observations is needed to confirm/explain these results.

  17. Climate change, air quality, and human health.

    PubMed

    Kinney, Patrick L

    2008-11-01

    Weather and climate play important roles in determining patterns of air quality over multiple scales in time and space, owing to the fact that emissions, transport, dilution, chemical transformation, and eventual deposition of air pollutants all can be influenced by meteorologic variables such as temperature, humidity, wind speed and direction, and mixing height. There is growing recognition that development of optimal control strategies for key pollutants like ozone and fine particles now requires assessment of potential future climate conditions and their influence on the attainment of air quality objectives. In addition, other air contaminants of relevance to human health, including smoke from wildfires and airborne pollens and molds, may be influenced by climate change. In this study, the focus is on the ways in which health-relevant measures of air quality, including ozone, particulate matter, and aeroallergens, may be affected by climate variability and change. The small but growing literature focusing on climate impacts on air quality, how these influences may play out in future decades, and the implications for human health is reviewed. Based on the observed and anticipated impacts, adaptation strategies and research needs are discussed. PMID:18929972

  18. The Selection of Q-Switch for a 350mJ Air-borne 2-micron Wind Lidar

    NASA Technical Reports Server (NTRS)

    Petros, Mulugeta; Yu, Jirong; Trieu, Bo; Bai, Yingxin; Petzar, Paul; Singh, Upendra N.

    2008-01-01

    In the process of designing a coherent, high energy 2micron, Doppler wind Lidar, various types of Q-Switch materials and configurations have been investigated for the oscillator. Designing an oscillator with a relatively low gain laser material, presents challenges related to the management high internal circulating fluence due to high reflective output coupler. This problem is compounded by the loss of hold-off. In addition, the selection has to take into account the round trip optical loss in the resonator and the loss of hold-off. For this application, a Brewster cut 5mm aperture, fused silica AO Q-switch is selected. Once the Q-switch is selected various rf frequencies were evaluated. Since the Lidar has to perform in single longitudinal and transverse mode with transform limited line width, in this paper, various seeding configurations are presented in the context of Q-Switch diffraction efficiency. The master oscillator power amplifier has demonstrated over 350mJ output when the amplifier is operated in double pass mode and higher than 250mJ when operated in single pass configuration. The repetition rate of the system is 10Hz and the pulse length 200ns.

  19. Measuring air-sea gas-exchange velocities in a large-scale annular wind-wave tank

    NASA Astrophysics Data System (ADS)

    Mesarchaki, E.; Kräuter, C.; Krall, K. E.; Bopp, M.; Helleis, F.; Williams, J.; Jähne, B.

    2015-01-01

    In this study we present gas-exchange measurements conducted in a large-scale wind-wave tank. Fourteen chemical species spanning a wide range of solubility (dimensionless solubility, α = 0.4 to 5470) and diffusivity (Schmidt number in water, Scw = 594 to 1194) were examined under various turbulent (u10 = 0.73 to 13.2 m s-1) conditions. Additional experiments were performed under different surfactant modulated (two different concentration levels of Triton X-100) surface states. This paper details the complete methodology, experimental procedure and instrumentation used to derive the total transfer velocity for all examined tracers. The results presented here demonstrate the efficacy of the proposed method, and the derived gas-exchange velocities are shown to be comparable to previous investigations. The gas transfer behaviour is exemplified by contrasting two species at the two solubility extremes, namely nitrous oxide (N2O) and methanol (CH3OH). Interestingly, a strong transfer velocity reduction (up to a factor of 3) was observed for the relatively insoluble N2O under a surfactant covered water surface. In contrast, the surfactant effect for CH3OH, the high solubility tracer, was significantly weaker.

  20. Analysis of Building Envelope Insulation Performance Utilizing Integrated Temperature and Humidity Sensors

    PubMed Central

    Hung, San-Shan; Chang, Chih-Yuan; Hsu, Cheng-Jui; Chen, Shih-Wei

    2012-01-01

    A major cause of high energy consumption for air conditioning in indoor spaces is the thermal storage characteristics of a building's envelope concrete material; therefore, the physiological signals (temperature and humidity) within concrete structures are an important reference for building energy management. The current approach to measuring temperature and humidity within concrete structures (i.e., thermocouples and fiber optics) is limited by problems of wiring requirements, discontinuous monitoring, and high costs. This study uses radio frequency integrated circuits (RFIC) combined with temperature and humidity sensors (T/H sensors) for the design of a smart temperature and humidity information material (STHIM) that automatically, regularly, and continuously converts temperature and humidity signals within concrete and transmits them by radio frequency (RF) to the Building Physiology Information System (BPIS). This provides a new approach to measurement that incorporates direct measurement, wireless communication, and real-time continuous monitoring to assist building designers and users in making energy management decisions and judgments. PMID:23012529