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Sample records for air temperature simulations

  1. 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.

  2. Simulation of air and ground temperatures in PMIP3/CMIP5 last millennium simulations: implications for climate reconstructions from borehole temperature profiles

    NASA Astrophysics Data System (ADS)

    García-García, A.; Cuesta-Valero, F. J.; Beltrami, H.; Smerdon, J. E.

    2016-04-01

    For climate models to simulate the continental energy storage of the Earth’s energy budget they must capture the processes that partition energy across the land-atmosphere boundary. We evaluate herein the thermal consequences of these processes as simulated by models in the third phase of the paleoclimate modelling intercomparison project and the fifth phase of the coupled model intercomparison project (PMIP3/CMIP5). We examine air and ground temperature tracking at decadal and centennial time-scales within PMIP3 last-millennium simulations concatenated to historical simulations from the CMIP5 archive. We find a strong coupling between air and ground temperatures during the summer from 850 to 2005 CE. During the winter, the insulating effect of snow and latent heat exchanges produce a decoupling between the two temperatures in the northern high latitudes. Additionally, we use the simulated ground surface temperatures as an upper boundary condition to drive a one-dimensional conductive model in order to derive synthetic temperature-depth profiles for each PMIP3/CMIP5 simulation. Inversion of these subsurface profiles yields temperature trends that retain the low-frequency variations in surface air temperatures over the last millennium for all the PMIP3/CMIP5 simulations regardless of the presence of seasonal decoupling in the simulations. These results demonstrate the robustness of surface temperature reconstructions from terrestrial borehole data and their interpretation as indicators of past surface air temperature trends and continental energy storage.

  3. Simulation of Air and Ground Temperatures in PMIP3/CMIP5 Last Millennium Simulations: Implications for Climate Reconstructions from Borehole Temperature Profiles

    NASA Astrophysics Data System (ADS)

    Beltrami, Hugo; García-García, Almudena; José Cuesta-Valero, Francisco; Smerdon, Jason

    2016-04-01

    For General Circulation Models (GCMs) to simulate the continental energy storage of the Earth's energy budget it is crucial that they correctly capture the processes that partition energy across the land-atmosphere boundary. We evaluate herein the characteristics of these processes as simulated by models in the third phase of the Paleoclimate Modelling Intercomparison Project and the fifth phase of the Coupled Model Intercomparison Project (PMIP3/CMIP5). We examine the seasonal differences between air and ground temperatures within PMIP3 last-millennium simulations concatenated with historical simulations from the CMIP5 archive. We find a strong air-ground coupling during the summer from 850 to 2000 CE. During the winter, the insulating effect of snow and latent heat exchanges produce a decoupling between air and ground temperatures in the northern high latitudes. Additionally, we use the simulated temperature trends as an upper boundary condition to force a one-dimensional conductive model to derive synthetic temperature-depth profiles for each PMIP3/CMIP5 simulation. The inversions of these subsurface profiles yield temperature trends that retain the surface temperature variations of the last millennium for all the PMIP3/CMIP5 simulations. These results support the use of underground temperatures to reconstruct past changes in ground surface temperature and to estimate the continental energy storage.

  4. Influence of Air Temperature Difference on the Snow Melting Simulation of SWAT Model

    NASA Astrophysics Data System (ADS)

    YAN, Y.; Onishi, T.

    2013-12-01

    The temperature-index models are commonly used to simulate the snowmelt process in mountain areas because of its good performance, low data requirements, and computational simplicity. Widely used distributed hydrological model: Soil and Water Assessment Tool (SWAT) model is also using a temperature-index module. However, the lack of monitoring air temperature data still involves uncertainties and errors in its simulation performance especially in data sparse area. Thus, to evaluate the different air temperature data influence on the snow melt of the SWAT model, five different air temperature data are applied in two different Russia basins (Birobidjan basin and Malinovka basin). The data include the monitoring air temperature data (TM), NCEP reanalysis data (TNCEP), the dataset created by inverse distance weighted interpolation (IDW) method (TIDW), the dataset created by improved IDW method considering the elevation influence (TIDWEle), and the dataset created by using linear regression and MODIS Land Surface Temperature (LST) data (TLST). Among these data, the TLST , the TIDW and TIDWEle data have the higher spatial density, while the TNCEP and TM DATA have the most valid monitoring value for daily scale. The daily simulation results during the snow melting seasons (March, April and May) showed reasonable results in both test basins for all air temperature data. While R2 and NSE in Birobidjan basin are around 0.6, these values in Malinovka basin are over 0.75. Two methods: Generalized Likelihood Uncertainty Estimation (GLUE) and Sequential Uncertainty Fitting, version. 2 (SUFI-2) were used for model calibration and uncertainty analysis. The evolution index is p-factor which means the percentage of measured data bracketed by the 95% Prediction Uncertainty (95PPU). The TLST dataset always obtained the best results in both basins compared with other datasets. On the other hand, the two IDW based method get the worst results among all the scenarios. Totally, the

  5. Performance of a hydrogen burner to simulate air entering scramjet combustors. [simulation of total temperature, total pressure, and volume fraction of oxygen of air at flight conditions

    NASA Technical Reports Server (NTRS)

    Russin, W. R.

    1974-01-01

    Tests were conducted to determine the performance of a hydrogen burner used to produce a test gas that simulates air entering a scramjet combustor at various flight conditions. The test gas simulates air in that it duplicates the total temperature, total pressure, and the volume fraction of oxygen of air at flight conditions. The main objective of the tests was to determine the performance of the burner as a function of the effective exhaust port area. The conclusions were: (1) pressure oscillations of the chugging type were reduced in amplitude to plus or minus 2 percent of the mean pressure level by proper sizing of hydrogen, oxygen, and air injector flow areas; (2) combustion efficiency remained essentially constant as the exhaust port area was increased by a factor of 3.4; (3) the mean total temperature determined from integrating the exit radial gas property profiles was within plus or minus 5 percent of the theoretical bulk total temperature; (4) the measured exit total temperature profile had a local peak temperature more than 30 percent greater than the theoretical bulk total temperature; and (5) measured heat transfer to the burner liner was 75 percent of that predicted by theory based on a flat radial temperature profile.

  6. Mesoscale climatic simulation of surface air temperature cooling by highly reflective greenhouses in SE Spain.

    PubMed

    Campra, Pablo; Millstein, Dev

    2013-01-01

    A long-term local cooling trend in surface air temperature has been monitored at the largest concentration of reflective greenhouses in the world, at the Province of Almeria, SE Spain, associated with a dramatic increase in surface albedo in the area. The availability of reliable long-term climatic field data at this site offers a unique opportunity to test the skill of mesoscale meteorological models describing and predicting the impacts of land use change on local climate. Using the Weather Research and Forecast (WRF) mesoscale model, we have run a sensitivity experiment to simulate the impact of the observed surface albedo change on monthly and annual surface air temperatures. The model output showed a mean annual cooling of 0.25 °C associated with a 0.09 albedo increase, and a reduction of 22.8 W m(-2) of net incoming solar radiation at surface. Mean reduction of summer daily maximum temperatures was 0.49 °C, with the largest single-day decrease equal to 1.3 °C. WRF output was evaluated and compared with observations. A mean annual warm bias (MBE) of 0.42 °C was estimated. High correlation coefficients (R(2) > 0.9) were found between modeled and observed values. This study has particular interest in the assessment of the potential for urban temperature cooling by cool roofs deployment projects, as well as in the evaluation of mesoscale climatic models performance. PMID:24074145

  7. Simulation of effects of direction and air flow speed on temperature distribution in the room covered by various roof materials

    NASA Astrophysics Data System (ADS)

    Sukanto, H.; Budiana, E. P.; Putra, B. H. H.

    2016-03-01

    The objective of this research is to get a comparison of the distribution of the room temperature by using three materials, namely plastic-rubber composite, clay, and asbestos. The simulation used Ansys Fluent to get the temperature distribution. There were two conditions in this simulations, first the air passing beside the room and second the air passing in front of the room. Each condition will be varied with the air speed of 1 m/s, 2 m/s, 3 m/s, 4 m/s, 5 m/s for each material used. There are three heat transfers in this simulation, namely radiation, convection, and conduction. Based on the ANSI/ ASHRAE Standard 55-2004, the results of the simulation showed that the best temperature distribution was the roof of plastic-rubber composites.

  8. Simulation of the effect of an increase in methane on air temperature

    NASA Astrophysics Data System (ADS)

    Bi, Yun; Chen, Yuejuan; Zhou, Renjun; Yi, Mingjian; Deng, Shumei

    2011-01-01

    The infrared radiative effect of methane was analyzed using the 2D, interactive chemical dynamical radiative SOCRATES model of the National Center for Atmospheric Research. Then, a sensitivity experiment, with the methane volume mixing ratio increased by 10%, was carried out to study the influence of an increase of methane on air temperature. The results showed that methane has a heating effect through the infrared radiative process in the troposphere and a cooling effect in the stratosphere. However, the cooling effect of the methane is much smaller than that of water vapor in the stratosphere and is negligible in the mesosphere. The simulation results also showed that when methane concentration is increased by 10%, the air temperature lowers in the stratosphere and mesosphere and increases in the troposphere. The cooling can reach 0.2 K at the stratopause and can vary from 0.2-0.4 K in the mesosphere, and the temperature rise varies by around 0.001-0.002 K in the troposphere. The cooling results from the increase of the infrared radiative cooling rate caused by increased water vapor and O3 concentration, which are stimulated by the increase in methane in most of the stratosphere. The infrared radiation cooling of methane itself is minor. The depletion of O3 stimulated by the methane increase results indirectly in a decrease in the rate of solar radiation heating, producing cooling in the stratopause and mesosphere. The tropospheric warming is mainly caused by the increase of methane, which produces infrared radiative heating. The increase in H2O and O3 caused by the methane increase also contributes to a rise in temperature in the troposphere.

  9. Numerical simulation on pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Zhu, Jianguo; Ouyang, Ziqu; Lu, Qinggang

    2013-06-01

    High temperature air combustion is a prospecting technology in energy saving and pollutants reduction. Numerical simulation on pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed was presented. The down-fired combustor, taken as the calculation domain, has the diameter of 220 mm and the height of 3000 mm. 2 cases with air staging combustion are simulated. Compared the simulation results with experimental data, there is a good agreement. It is found that the combustion model and NOx formation model are applicable to simulate the pulverized coal combustion and NOx emissions in high temperature air from circulating fluidized bed. The results show that there is a uniform temperature profile along the axis of the down-fired combustor. The NOx emissions are lower than those of ordinary pulverized coal combustion, and the NOx emissions are 390 mg/m3 and 352 mg/m3 in Case 1 and Case 2, respectively. At the range of 300-600 mm below the nozzle, the NO concentration decreases, mainly resulting from some homogeneous reactions and heterogeneous reaction. NO concentration has a little increase at the position of 800 mm below the nozzle as the tertiary air supplied to the combustor at the position of 600 mm below the nozzle.

  10. Impact of an improved WRF urban canopy model on diurnal air temperature simulation over northern Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Chuan-Yao; Su, Chiung-Jui; Kusaka, Hiroyuki; Akimoto, Yuko; Sheng, Yang-Fan; Huang, -Chuan, Jr.; Hsu, Huang-Hsiung

    2016-02-01

    This study evaluates the impact of urbanization over northern Taiwan using the Weather Research and Forecasting (WRF) Model coupled with the Noah land-surface model and a modified urban canopy model (WRF-UCM2D). In the original UCM coupled to WRF (WRF-UCM), when the land use in the model grid is identified as "urban", the urban fraction value is fixed. Similarly, the UCM assumes the distribution of anthropogenic heat (AH) to be constant. This may not only lead to over- or underestimation of urban fraction and AH in urban and non-urban areas, but spatial variation also affects the model-estimated temperature. To overcome the abovementioned limitations and to improve the performance of the original UCM model, WRF-UCM is modified to consider the 2-D urban fraction and AH (WRF-UCM2D).The two models were found to have comparable temperature simulation performance for urban areas, but large differences in simulated results were observed for non-urban areas, especially at nighttime. WRF-UCM2D yielded a higher correlation coefficient (R2) than WRF-UCM (0.72 vs. 0.48, respectively), while bias and RMSE achieved by WRF-UCM2D were both significantly smaller than those attained by WRF-UCM (0.27 and 1.27 vs. 1.12 and 1.89, respectively). In other words, the improved model not only enhanced correlation but also reduced bias and RMSE for the nighttime data of non-urban areas. WRF-UCM2D performed much better than WRF-UCM at non-urban stations with a low urban fraction during nighttime. The improved simulation performance of WRF-UCM2D in non-urban areas is attributed to the energy exchange which enables efficient turbulence mixing at a low urban fraction. The result of this study has a crucial implication for assessing the impacts of urbanization on air quality and regional climate.

  11. Evaluating the Adequacy of Simulating Maximum and Minimum Daily Air Temperature with the Normal Distribution.

    NASA Astrophysics Data System (ADS)

    Harmel, R. D.; Richardson, C. W.; Hanson, C. L.; Johnson, G. L.

    2002-07-01

    Weather simulation models are commonly used to generate synthetic daily weather for use in studies of crop growth, water quality, water availability, soil erosion, climate change, and so on. Synthetic weather sequences are needed if long-term measured data are not available, measured data contain missing records, collection of actual data is cost or time prohibitive, or when necessary to simulate impacts of future climate scenarios. Most weather generators are capable of producing one or more components of weather such as precipitation, temperature, solar radiation, humidity, and wind speed. This study focused on one generation component, the procedure commonly used by weather simulation models to generate daily maximum and minimum temperature. The normal distribution is used by most weather generators (including USCLIMATE, WXGEN, LARS-WG, CLIMGEN, and CLIGEN) to generate daily maximum and minimum temperature values. The objective of this study was to analyze the adequacy of generating temperature data from the normal distribution. To accomplish this objective, the assumption of normality in measured daily temperatures was evaluated by testing the hypothesis that daily minimum and maximum temperature are normally distributed for each month. In addition, synthetic temperature records generated with the normal distribution were compared with measured temperature records. Based on these analyses, it was determined that measured daily maximum and minimum temperature are generally not normally distributed in each month but often are slightly skewed, which contradicts the assumption of normality used by most weather generators. In addition, generating temperature from the normal distribution resulted in several physically improbable values.

  12. Coupling Between Air and Ground Temperatures in PMIP3/CMIP5 Last Millennium Simulations and the Implications for Climate Reconstructions from Borehole Temperature Profiles

    NASA Astrophysics Data System (ADS)

    Beltrami, H.; García-García, A.; Cuesta-Valero, F. J.; Smerdon, J. E.

    2015-12-01

    The continental energy storage for the second half of the 20th20^{th} century has been estimated from geothermal data to be about 7±1×1021J7 ± 1 × 10^{21} J under the assumption that there exists a long-term coupling between the lower atmosphere and the continental subsurface. For General Circulation Models (GCMs) to simulate the continental energy storage of the Earth's energy budget, however, it is crucial that they correctly capture the processes that partition energy across the land-atmosphere boundary. We evaluate herein the characteristics of these processes as simulated by models in the third phase of the Paleoclimate Modelling Intercomparison Project and the fifth phase of the Coupled Model Intercomparison Project (PMIP33/CMIP55). We examine the seasonal differences between air and ground temperatures within PMIP3 last-millennium simulations concatenated with historical simulations from the CMIP5 archive. We find a strong air-ground coupling during the summer from 850850 to 20002000 CE. During the winter, the insulating effect of snow and latent heat exchanges produce a decoupling between air and ground temperatures in the northern high latitudes. These seasonal differences decrease with depth, supporting the central assumption of climate reconstructions from borehole temperature profiles. Additionally, we use the simulated temperature trends as an upper boundary condition to force a one-dimensional conductive model to derive synthetic temperature-depth profiles for each PMIP3/CMIP5 simulation. The inversions of these subsurface profiles yield temperature trends that retain the surface temperature variations of the last millennium for all the PMIP3/CMIP5 simulations. These results support the use of underground temperatures to reconstruct past changes in ground surface temperature and to estimate the continental energy storage. Results also provide guidance for improving the land-surface components of GCMs.

  13. Controlled simulation of optical turbulence in a temperature gradient air chamber

    NASA Astrophysics Data System (ADS)

    Toselli, Italo; Wang, Fei; Korotkova, Olga

    2016-05-01

    Atmospheric turbulence simulator is built and characterized for in-lab optical wave propagation with controlled strength of the refractive-index fluctuations. The temperature gradients are generated by a sequence of heat guns with controlled individual strengths. The temperature structure functions are measured in two directions transverse to propagation path with the help of a thermocouple array and used for evaluation of the corresponding refractive-index structure functions of optical turbulence.

  14. The influence of air temperature inversions on snowmelt and glacier mass-balance simulations, Ammassalik island, SE Greenland

    SciTech Connect

    Mernild, Sebastian Haugard; Liston, Glen

    2009-01-01

    In many applications, a realistic description of air temperature inversions is essential for accurate snow and glacier ice melt, and glacier mass-balance simulations. A physically based snow-evolution modeling system (SnowModel) was used to simulate eight years (1998/99 to 2005/06) of snow accumulation and snow and glacier ice ablation from numerous small coastal marginal glaciers on the SW-part of Ammassalik Island in SE Greenland. These glaciers are regularly influenced by inversions and sea breezes associated with the adjacent relatively low temperature and frequently ice-choked fjords and ocean. To account for the influence of these inversions on the spatiotemporal variation of air temperature and snow and glacier melt rates, temperature inversion routines were added to MircoMet, the meteorological distribution sub-model used in SnowModel. The inversions were observed and modeled to occur during 84% of the simulation period. Modeled inversions were defined not to occur during days with strong winds and high precipitation rates due to the potential of inversion break-up. Field observations showed inversions to extend from sea level to approximately 300 m a.s.l., and this inversion level was prescribed in the model simulations. Simulations with and without the inversion routines were compared. The inversion model produced air temperature distributions with warmer lower elevation areas and cooler higher elevation areas than without inversion routines due to the use of cold sea-breeze base temperature data from underneath the inversion. This yielded an up to 2 weeks earlier snowmelt in the lower areas and up to 1 to 3 weeks later snowmelt in the higher elevation areas of the simulation domain. Averaged mean annual modeled surface mass-balance for all glaciers (mainly located above the inversion layer) was -720 {+-} 620 mm w.eq. y{sup -1} for inversion simulations, and -880 {+-} 620 mm w.eq. y{sup -1} without the inversion routines, a difference of 160 mm w.eq. y

  15. Regional and large-scale influences on seasonal to interdecadal variability in Caribbean surface air temperature in CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Ryu, Jung-Hee; Hayhoe, Katharine

    2015-07-01

    We evaluate the ability of global climate models participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5) to reproduce observed seasonality and interannual variability of temperature over the Caribbean, and compare these with simulations from atmosphere-only (AMIP5) and previous-generation CMIP3 models. Compared to station and gridded observations, nearly every CMIP5, CMIP3 and AMIP5 simulation tends to reproduce the primary inter-regional features of the Caribbean annual temperature cycle. In most coupled model simulations, however, boreal summer temperature lags observations by about 1 month, with a similar lag in the simulated annual cycle of sea surface temperature (SST), and a systematic cold bias in both climatological annual mean air temperature and SST. There is some improvement from CMIP3 to CMIP5 but the bias is still marked compared to AMIP5 and observations, implying that biases in the annual temperature cycle may originate in the ocean component of the coupled models. This also suggests a tendency for models to over-emphasize the influence of SSTs on near-surface temperature, a bias that may be exacerbated by model tendency to over-estimate ocean mixed layer depth as well. In contrast, we find that both coupled and atmosphere-only models tend to reasonably simulate the response of observed temperature to global temperature, to regional and large-scale variability across the Caribbean region and the Gulf of Mexico, and even to more remote Atlantic and Pacific influences. These findings contribute to building confidence in the ability of coupled models to simulate the effect of global-scale change on the Caribbean.

  16. Evaluation of air-soil temperature relationships simulated by land surface models during winter across the permafrost region

    NASA Astrophysics Data System (ADS)

    Wang, Wenli; Rinke, Annette; Moore, John C.; Ji, Duoying; Cui, Xuefeng; Peng, Shushi; Lawrence, David M.; McGuire, A. David; Burke, Eleanor J.; Chen, Xiaodong; Decharme, Bertrand; Koven, Charles; MacDougall, Andrew; Saito, Kazuyuki; Zhang, Wenxin; Alkama, Ramdane; Bohn, Theodore J.; Ciais, Philippe; Delire, Christine; Gouttevin, Isabelle; Hajima, Tomohiro; Krinner, Gerhard; Lettenmaier, Dennis P.; Miller, Paul A.; Smith, Benjamin; Sueyoshi, Tetsuo; Sherstiukov, Artem B.

    2016-08-01

    A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyse simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models, and compare them with observations from 268 Russian stations. There are large cross-model differences in the simulated differences between near-surface soil and air temperatures (ΔT; 3 to 14 °C), in the sensitivity of soil-to-air temperature (0.13 to 0.96 °C °C-1), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, hence guide improvements to the model's conceptual structure and process parameterisations. Models with better performance apply multilayer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (13.19 to 15.77 million km2). However, there is not a simple relationship between the sophistication of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, because several other factors, such as soil depth used in the models, the treatment of soil organic matter content, hydrology and vegetation cover, also affect the simulated permafrost distribution.

  17. Air Shower Simulations

    SciTech Connect

    Alania, Marco; Gomez, Adolfo V. Chamorro; Araya, Ignacio J.; Huerta, Humberto Martinez; Flores, Alejandra Parra; Knapp, Johannes

    2009-04-30

    Air shower simulations are a vital part of the design of air shower experiments and the analysis of their data. We describe the basic features of air showers and explain why numerical simulations are the appropriate approach to model the shower simulation. The CORSIKA program, the standard simulation program in this field, is introduced and its features, performance and limitations are discussed. The basic principles of hadronic interaction models and some gerneral simulation techniques are explained. Also a brief introduction to the installation and use of CORSIKA is given.

  18. Computational simulation of temperature and velocity distribution in human upper respiratory airway during inhalation of hot air.

    PubMed

    Goodarzi-Ardakani, V; Taeibi-Rahni, M; Salimi, M R; Ahmadi, G

    2016-03-01

    The present study provides an accurate simulation of velocity and temperature distributions of inhalation thermal injury in a human upper airway, including vestibule, nasal cavity, paranasal sinuses, nasopharynx, oropharynx, larynx, and upper part of main bronchus. To this end, a series of CT scan images, taken from an adult woman, was used to construct a three dimensional model. The airway walls temperature was adjusted according to existing in vivo temperature measurements. Also, in order to cover all breathing activities, five different breathing flow rates (10, 15, 20, 30, and 40 l/min) and different ambient air temperatures (100, 200, 300, 400, and 500 °C) were studied. Different flow regimes, including laminar, transitional, and turbulence were considered and the simulations were validated using reliable experimental data. The results show that nostrils, vestibule, and nasal cavity are damaged more than other part of airway. Finally, In order to obtain the heat flux through the walls, correlations for Nusselt number for each individual parts of airway (vestibule, main upper airway, nasopharynx etc.,) are proposed. PMID:26777422

  19. Simulation of free air CO2 enriched wheat growth and interaction with water, nitrogen, and temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural system simulation models are key tools for assessment of possible impacts of climate change on crop production and environmental quality. In this study, the CERES-wheat 4.0 module in the RZWQM2 model was calibrated and validated for simulating spring wheat grown under elevated CO2 condi...

  20. Impact of an improved WRF-urban canopy model on diurnal air temperature simulation over northern Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Chuan-yao; Su, Chiung-Jui; Kusaka, Hiroyuki; Akimoto, Yuko; Sheng, Yang Fan; Huang, Chuan, Jr.

    2016-04-01

    This study evaluated the impact of urbanization over northern Taiwan using the Weather Research and Forecasting (WRF) model coupled with the Noah land-surface model and a modified Urban Canopy Model (WRF-UCM2D). In the original UCM coupled in WRF (WRF-UCM), when the land use in the model grid is identified as "urban", the urban fraction value is fixed. Similarly, the UCM assumes the distribution of anthropogenic heat (AH) to be constant. Such not only may lead to over- or underestimation of urban fraction and AH in urban and non-urban areas, spatial variation also affects the model-estimated temperature. To overcome the above-mentioned limitations and to improve the performance of the original UCM model, WRF-UCM is modified to consider the 2-D urban fraction and AH (WRF-UCM2D). The two models were found to have comparable temperature simulation performance for urban areas but large differences in simulated results were observed for non-urban, especially at nighttime. WRF-UCM2D yielded a higher correlation coefficient (R2) than WRF-UCM (0.72 vs. 0.48, respectively), while bias and RMSE achieved by WRF-UCM2D were both significantly smaller than those attained by WRF-UCM (0.27 and 1.27 vs. 1.12 and 1.89, respectively). In other words, the improved model not only enhanced correlation but also reduced bias and RMSE for the nighttime data of non-urban areas. WRF-UCM2D performed much better than WRF-UCM at non-urban stations with low urban fraction during nighttime. The improved simulation performance of WRF-UCM2D at non-urban areas is attributed to the energy exchange which enables efficient turbulence mixing at low urban fraction. The achievement of this study has a crucial implication for assessing the impacts of urbanization on air quality and regional climate.

  1. Increased air temperature during simulated autumn conditions impairs photosynthetic electron transport between photosystem II and photosystem I.

    PubMed

    Busch, Florian; Hüner, Norman P A; Ensminger, Ingo

    2008-05-01

    Changes in temperature and daylength trigger physiological and seasonal developmental processes that enable evergreen trees of the boreal forest to withstand severe winter conditions. Climate change is expected to increase the autumn air temperature in the northern latitudes, while the natural decreasing photoperiod remains unaffected. As shown previously, an increase in autumn air temperature inhibits CO2 assimilation, with a concomitant increased capacity for zeaxanthin-independent dissipation of energy exceeding the photochemical capacity in Pinus banksiana. In this study, we tested our previous model of antenna quenching and tested a limitation in intersystem electron transport in plants exposed to elevated autumn air temperatures. Using a factorial design, we dissected the effects of temperature and photoperiod on the function as well as the stoichiometry of the major components of the photosynthetic electron transport chain in P. banksiana. Natural summer conditions (16-h photoperiod/22 degrees C) and late autumn conditions (8-h photoperiod/7 degrees C) were compared with a treatment of autumn photoperiod with increased air temperature (SD/HT: 8-h photoperiod/22 degrees C) and a treatment with summer photoperiod and autumn temperature (16-h photoperiod/7 degrees C). Exposure to SD/HT resulted in an inhibition of the effective quantum yield associated with a decreased photosystem II/photosystem I stoichiometry coupled with decreased levels of Rubisco. Our data indicate that a greater capacity to keep the primary electron donor of photosystem I (P700) oxidized in plants exposed to SD/HT compared with the summer control may be attributed to a reduced rate of electron transport from the cytochrome b6f complex to photosystem I. Photoprotection under increased autumn air temperature conditions appears to be consistent with zeaxanthin-independent antenna quenching through light-harvesting complex II aggregation and a decreased efficiency in energy transfer from the

  2. Increased Air Temperature during Simulated Autumn Conditions Impairs Photosynthetic Electron Transport between Photosystem II and Photosystem I1[OA

    PubMed Central

    Busch, Florian; Hüner, Norman P.A.; Ensminger, Ingo

    2008-01-01

    Changes in temperature and daylength trigger physiological and seasonal developmental processes that enable evergreen trees of the boreal forest to withstand severe winter conditions. Climate change is expected to increase the autumn air temperature in the northern latitudes, while the natural decreasing photoperiod remains unaffected. As shown previously, an increase in autumn air temperature inhibits CO2 assimilation, with a concomitant increased capacity for zeaxanthin-independent dissipation of energy exceeding the photochemical capacity in Pinus banksiana. In this study, we tested our previous model of antenna quenching and tested a limitation in intersystem electron transport in plants exposed to elevated autumn air temperatures. Using a factorial design, we dissected the effects of temperature and photoperiod on the function as well as the stoichiometry of the major components of the photosynthetic electron transport chain in P. banksiana. Natural summer conditions (16-h photoperiod/22°C) and late autumn conditions (8-h photoperiod/7°C) were compared with a treatment of autumn photoperiod with increased air temperature (SD/HT: 8-h photoperiod/22°C) and a treatment with summer photoperiod and autumn temperature (16-h photoperiod/7°C). Exposure to SD/HT resulted in an inhibition of the effective quantum yield associated with a decreased photosystem II/photosystem I stoichiometry coupled with decreased levels of Rubisco. Our data indicate that a greater capacity to keep the primary electron donor of photosystem I (P700) oxidized in plants exposed to SD/HT compared with the summer control may be attributed to a reduced rate of electron transport from the cytochrome b6f complex to photosystem I. Photoprotection under increased autumn air temperature conditions appears to be consistent with zeaxanthin-independent antenna quenching through light-harvesting complex II aggregation and a decreased efficiency in energy transfer from the antenna to the photosystem

  3. Air Combat Simulator

    NASA Technical Reports Server (NTRS)

    1981-01-01

    By adapting COSMIC's One-on-One Adaptive Maneuvering Logic (AML) for two versus one simulation, Link Division was able to reduce software and other design/development costs. Enhancements to the AML program developed by Link for simulation of two-versus one combat, two trainees can simultaneously engage a computer driven target, thereby doubling the training utility of the simulator.

  4. Evaluation of surface air temperature and urban effects in Japan simulated by non-hydrostatic regional climate model

    NASA Astrophysics Data System (ADS)

    Murata, A.; Sasaki, H.; Hanafusa, M.; Kurihara, K.

    2012-12-01

    We evaluated the performance of a well-developed nonhydrostatic regional climate model (NHRCM) with a spatial resolution of 5 km with respect to temperature in the present-day climate of Japan, and estimated urban heat island (UHI) intensity by comparing the model results and observations. The magnitudes of root mean square error (RMSE) and systematic error (bias) for the annual average of daily mean (Ta), maximum (Tx), and minimum (Tn) temperatures are within 1.5 K, demonstrating that the temperatures of the present-day climate are reproduced well by NHRCM. These small errors indicate that temperature variability produced by local-scale phenomena is represented well by the model with a higher spatial resolution. It is also found that the magnitudes of RMSE and bias in the annually-average Tx are relatively large compared with those in Ta and Tn. The horizontal distributions of the error, defined as the difference between simulated and observed temperatures (simulated minus observed), illustrate negative errors in the annually-averaged Tn in three major metropolitan areas: Tokyo, Osaka, and Nagoya. These negative errors in urban areas affect the cold bias in the annually-averaged Tx. The relation between the underestimation of temperature and degree of urbanization is therefore examined quantitatively using National Land Numerical Information provided by the Ministry of Land, Infrastructure, Transport, and Tourism. The annually-averaged Ta, Tx, and Tn are all underestimated in the areas where the degree of urbanization is relatively high. The underestimations in these areas are attributed to the treatment of urban areas in NHRCM, where the effects of urbanization, such as waste heat and artificial structures, are not included. In contrast, in rural areas, the simulated Tx is underestimated and Tn is overestimated although the errors in Ta are small. This indicates that the simulated diurnal temperature range is underestimated. The reason for the relatively large

  5. An Analysis of Simulated and Observed Global Mean Near-Surface Air Temperature Anomalies from 1979 to 1999: Trends and Attribution of Causes

    NASA Technical Reports Server (NTRS)

    MacKay, R. M.; Ko, M. K. W.

    2001-01-01

    The 1979 - 1999 response of the climate system to variations in solar spectral irradiance is estimated by comparing the global averaged surface temperature anomalies simulated by a 2D (two dimensional) energy balance climate model to observed temperature anomalies. We perform a multiple regression of southern oscillation index and the individual model responses to solar irradiance variations, stratospheric and tropospheric aerosol loading, stratospheric ozone trends, and greenhouse gases onto each of five near-surface temperature anomaly data sets. We estimate the observed difference in global mean near surface air temperature attributable to the solar irradiance difference between solar maximum and solar minimum to be between 0.06 and 0.11 K, and that 1.1 - 3.8% of the total variance in monthly mean near-surface air temperature data is attributable to nations in solar spectral irradiance. For the five temperature data sets used in our analysis, the trends in raw monthly mean temperature anomaly data have a large range, spanning a factor of 3 from 0.06 to 0.17 K/decade. However. our analysis suggests that trends in monthly temperature anomalies attributable to the combination of greenhouse gas, stratospheric ozone, and tropospheric sulfate aerosol variations are much more consistent among data sets, ranging from 0.16 to 0.24 K/decade. Our model results suggest that roughly half of the warming from greenhouse gases is cancelled by the cooling from changes in stratospheric ozone. Tropospheric sulfate aerosol loading in the present day atmospheric contributes significantly to the net radiative forcing of the present day climate system. However, because the change in magnitude and latitudinal distribution of tropospheric sulfate aerosol has been small over the past 20 years, the change in the direct radiative forcing attributable to changes in aerosol loading over this time is also small.

  6. Increased air temperature during simulated autumn conditions does not increase photosynthetic carbon gain but affects the dissipation of excess energy in seedlings of the evergreen conifer Jack pine.

    PubMed

    Busch, Florian; Hüner, Norman P A; Ensminger, Ingo

    2007-03-01

    Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack pine (Pinus banksiana) in controlled environments during a simulated summer-autumn transition under natural conditions and conditions with altered air temperature and photoperiod. Using a factorial design, we dissected the effects of daylength and temperature. Control plants were grown at either warm summer conditions with 16-h photoperiod and 22 degrees C or conditions representing a cool autumn with 8 h/7 degrees C. To assess the impact of photoperiod and temperature on photosynthesis and energy dissipation, plants were also grown under either cold summer (16-h photoperiod/7 degrees C) or warm autumn conditions (8-h photoperiod/22 degrees C). Photosynthetic gas exchange was affected by both daylength and temperature. Assimilation and respiration rates under warm autumn conditions were only about one-half of the summer values but were similar to values obtained for cold summer and natural autumn treatments. In contrast, photosynthetic efficiency was largely determined by temperature but not by daylength. Plants of different treatments followed different strategies for dissipating excess energy. Whereas in the warm summer treatment safe dissipation of excess energy was facilitated via zeaxanthin, in all other treatments dissipation of excess energy was facilitated predominantly via increased aggregation of the light-harvesting complex of photosystem II. These differences were accompanied by a lower deepoxidation state and larger amounts of beta-carotene in the warm autumn

  7. Surface Temperature variability from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Dang, V. T.; Aumann, H. H.

    2015-12-01

    To address the existence and possible causes of the climate hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014for the day and night conditions. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We compare the satellite data with the new surface data produced by Karl et al. (2015) who denies the reality of the climate hiatus. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The day-night difference is an indicator of the anthropogenic trend. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  8. IAQPC: AN INDOOR AIR QUALITY SIMULATOR

    EPA Science Inventory

    The paper discusses an Indoor Air Quality Simulator for Personal Computers (IAQPC), developed in response to the growing need for quick accurate predictions of indoor air contamination levels. eating, ventilating, and air conditioning (HVAC) system designers need ways to determin...

  9. Simulation model air-to-air plate heat exchanger

    SciTech Connect

    Wetter, Michael

    1999-01-01

    A simple simulation model of an air-to-air plate heat exchanger is presented. The model belongs to a collection of simulation models that allows the eflcient computer simulation of heating, ventilation, and air-conditioning (HVAC) systems. The main emphasis of the models is to shorten computation time and to use only input data that are known in the design process of an HVAC system. The target of the models is to describe the behavior of HVAC components in the part-load operation mode, which is becoming increasingly important in energy eficient HVAC systems. The models are intended to be used for yearly energy calculations or load calculations with time steps of about 10 minutes or larger. Short- time dynamic effects, which are of interest for different aspects of control theory, are neglected. The part-load behavior is expressed in terms of the nominal condition and the dimensionless variation of the heat transfer with change of mass flow and temperature. The effectiveness- NTU relations are used to parametrize the convective heat transfer at nominal conditions and to compute the part-load condition. If the heat transfer coefficients on the two exchanger sides are not equal (i. e. due to partial bypassing of air), their ratio can be easily calculated and set as a parameter. The model is static and uses explicit equations only. The explicit model formulation ensures short computation time and numerical stability, which allows using the model with sophisticated engineering methods like automatic system optimization. This paper fully outlines the algorithm description and its simplifications. It is not tailored for any particular simulation program to ensure easy implementation in any simulation program.

  10. Visual air quality simulation techniques

    NASA Astrophysics Data System (ADS)

    Molenar, John V.; Malm, William C.; Johnson, Christopher E.

    Visual air quality is primarily a human perceptual phenomenon beginning with the transfer of image-forming information through an illuminated, scattering and absorbing atmosphere. Visibility, especially the visual appearance of industrial emissions or the degradation of a scenic view, is the principal atmospheric characteristic through which humans perceive air pollution, and is more sensitive to changing pollution levels than any other air pollution effect. Every attempt to quantify economic costs and benefits of air pollution has indicated that good visibility is a highly valued and desired environmental condition. Measurement programs can at best approximate the state of the ambient atmosphere at a few points in a scenic vista viewed by an observer. To fully understand the visual effect of various changes in the concentration and distribution of optically important atmospheric pollutants requires the use of aerosol and radiative transfer models. Communication of the output of these models to scientists, decision makers and the public is best done by applying modern image-processing systems to generate synthetic images representing the modeled air quality conditions. This combination of modeling techniques has been under development for the past 15 yr. Initially, visual air quality simulations were limited by a lack of computational power to simplified models depicting Gaussian plumes or uniform haze conditions. Recent explosive growth in low cost, high powered computer technology has allowed the development of sophisticated aerosol and radiative transfer models that incorporate realistic terrain, multiple scattering, non-uniform illumination, varying spatial distribution, concentration and optical properties of atmospheric constituents, and relative humidity effects on aerosol scattering properties. This paper discusses these improved models and image-processing techniques in detail. Results addressing uniform and non-uniform layered haze conditions in both

  11. Is Air Temperature Enough to Predict Lake Surface Temperature?

    NASA Astrophysics Data System (ADS)

    Piccolroaz, S.; Toffolon, M.; Majone, B.

    2014-12-01

    Lake surface water (LST) is a key factor that controls most of the physical and ecological processes occurring in lakes. Reliable estimates are especially important in the light of recent studies, which revealed that inland water bodies are highly sensitive to climate, and are rapidly warming throughout the world. However, an accurate estimation of LST usually requires a significant amount of information that is not always available. In this work, we present an application of air2water, a lumped model that simulates LST as a function of air temperature only. In addition, air2water allows for a qualitative evaluation of the depth of the epilimnion during the annual stratification cycle. The model consists in a simplification of the complete heat budget of the well-mixed surface layer, and has a few parameters (from 4 to 8 depending on the version) that summarize the role of the different heat flux components. Model calibration requires only air and water temperature data, possibly covering sufficiently long historical periods in order to capture inter-annual variability and long-term trends. During the calibration procedure, the information included in input data is retrieved to directly inform model parameters, which can be used to classify the thermal behavior of the lake. In order to investigate how thermal dynamics are related to morphological features, the model has been applied to 14 temperate lakes characterized by different morphological and hydrological conditions, by different sources of temperature data (buoys, satellite), and by variable frequency of acquisition. A good agreement between observed and simulated LST has been achieved, with a RMSE in the order of 1°C, which is fully comparable to the performances of more complex process-based models. This application allowed for a deeper understanding of the thermal response of lakes as a function of their morphology, as well as for specific analyses as for example the investigation of the exceptional

  12. Numerical simulation and nasal air-conditioning

    PubMed Central

    Keck, Tilman; Lindemann, Jörg

    2011-01-01

    Heating and humidification of the respiratory air are the main functions of the nasal airways in addition to cleansing and olfaction. Optimal nasal air conditioning is mandatory for an ideal pulmonary gas exchange in order to avoid desiccation and adhesion of the alveolar capillary bed. The complex three-dimensional anatomical structure of the nose makes it impossible to perform detailed in vivo studies on intranasal heating and humidification within the entire nasal airways applying various technical set-ups. The main problem of in vivo temperature and humidity measurements is a poor spatial and time resolution. Therefore, in vivo measurements are feasible only to a restricted extent, solely providing single temperature values as the complete nose is not entirely accessible. Therefore, data on the overall performance of the nose are only based on one single measurement within each nasal segment. In vivo measurements within the entire nose are not feasible. These serious technical issues concerning in vivo measurements led to a large number of numerical simulation projects in the last few years providing novel information about the complex functions of the nasal airways. In general, numerical simulations merely calculate predictions in a computational model, e.g. a realistic nose model, depending on the setting of the boundary conditions. Therefore, numerical simulations achieve only approximations of a possible real situation. The aim of this review is the synopsis of the technical expertise on the field of in vivo nasal air conditioning, the novel information of numerical simulations and the current state of knowledge on the influence of nasal and sinus surgery on nasal air conditioning. PMID:22073112

  13. Simulated Future Changes in Air Temperature and Precipitation Climatology in the Central Asia Cordex Region 8 BY Using RegCM 4.3.5

    NASA Astrophysics Data System (ADS)

    Ozturk, Tugba; Türkeş, Murat; Kurnaz, M. Levent

    2014-05-01

    In this study, projected future changes for the period of 2071-2100 in mean surface air temperature and precipitation climatology and variability over the large Central Asia region with respect to present climate (1971 to 2000) were simulated based on the RCP 4.5 and RCP 8.5 emission scenarios. Regional Climate Model (RegCM4.3) of the International Centre for Theoretical Physics (ICTP) was used for projections of future and present climate conditions. Hadley Global Environment Model 2 (HadGEM2) of the Met Office Hadley Centre was downscaled for the Cordex Region 8. We investigated the seasonal time-scale performance of RegCM4.3.5 in reproducing observed climatology over the domain of Central Asia by usingtwo different emission scenario datasets for three future periods. The regional model is capable of reproducing the observed climate with few exceptions, which are due to the meteorological and physical geographical complexities of the domain. For the future climatology of the domain, the regional model predicts relatively high warming in the warm season and northern part of the domain at cold season with a decrease in precipitation amounts almost all part of the domain. The results of our study showed that surface air temperatures in the region will increase from 3° C up to more than 7° C on average according to the emission scenarios for the period of 2070-2100 with respect to past period of 1970-2000. In the future, a decrease in the amount of precipitation is also predicted for the region. The projected warming and decrease in precipitation for the domain may strongly affect the ecological and socio-economic systems including agriculture, natural biomes, hydrology and water resources of this region, which is already a mostly arid and semi-arid environment. This work has been supported by Bogazici University BAP under project number 7362. One of the authors (MLK) was partially supported by Mercator-IPC Fellowship Program.

  14. Crowdsourcing urban air temperatures from smartphone battery temperatures

    NASA Astrophysics Data System (ADS)

    Overeem, Aart; Robinson, James C. R.; Leijnse, Hidde; Steeneveld, Gert-Jan; Horn, Berthold K. P.; Uijlenhoet, Remko

    2014-05-01

    Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. It has been shown that a straightforward heat transfer model can be employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. The methodology has been applied to Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree

  15. Temperature estimators in computer simulation

    NASA Astrophysics Data System (ADS)

    Jara, César; González-Cataldo, Felipe; Davis, Sergio; Gutiérrez, Gonzalo

    2016-05-01

    Temperature is a key physical quantity that is used to describe equilibrium between two bodies in thermal contact. In computer simulations, the temperature is usually estimated by means of the equipartition theorem, as an average over the kinetic energy. However, recent studies have shown that the temperature can be estimated using only the particles positions, which has been called configurational temperature. Through classical molecular dynamics simulations of 108-argon-atoms system, we compare the performance of four different temperature estimators: the usual kinetic temperature and three configurational temperatures, Our results show that the different estimators converge to the same value, but their fluctuations are different.

  16. Software for Simulating Air Traffic

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Bilimoria, Karl; Grabbe, Shon; Chatterji, Gano; Sheth, Kapil; Mulfinger, Daniel

    2006-01-01

    Future Air Traffic Management Concepts Evaluation Tool (FACET) is a system of software for performing computational simulations for evaluating advanced concepts of advanced air-traffic management. FACET includes a program that generates a graphical user interface plus programs and databases that implement computational models of weather, airspace, airports, navigation aids, aircraft performance, and aircraft trajectories. Examples of concepts studied by use of FACET include aircraft self-separation for free flight; prediction of air-traffic-controller workload; decision support for direct routing; integration of spacecraft-launch operations into the U.S. national airspace system; and traffic- flow-management using rerouting, metering, and ground delays. Aircraft can be modeled as flying along either flight-plan routes or great-circle routes as they climb, cruise, and descend according to their individual performance models. The FACET software is modular and is written in the Java and C programming languages. The architecture of FACET strikes a balance between flexibility and fidelity; as a consequence, FACET can be used to model systemwide airspace operations over the contiguous U.S., involving as many as 10,000 aircraft, all on a single desktop or laptop computer running any of a variety of operating systems. Two notable applications of FACET include: (1) reroute conformance monitoring algorithms that have been implemented in one of the Federal Aviation Administration s nationally deployed, real-time, operational systems; and (2) the licensing and integration of FACET with the commercially available Flight Explorer, which is an Internet- based, real-time flight-tracking system.

  17. Simulating Martian Temperatures

    NASA Astrophysics Data System (ADS)

    Buchanan, Randy K.

    2003-09-01

    The Mars Electrostatic Chamber (MEC) was designed to provide for research and testing relative to future missions to Mars. Environmental characteristics of Mars were emulated, including pressure, atmospheric composition, and temperature. Existing and newly acquired hardware were integrated with a centralized controller to bring about successful near-autonomous operation and temperature control. The MEC is principally comprised of systems that control atmospheric pressure, atmospheric content, and chamber temperature. The temperature control system is used to replicate temperatures within actual minimum and maximum values as would be experienced on Mars. Cryogenic liquid/gaseous nitrogen supplies as well as various heating techniques were used to obtain this temperature range. Fundamental to the stabilization of temperature within the chamber was the instrumentation of multiple temperature measurements and optimal control of extremely cold nitrogen. Through testing and characterization, cooling design modifications, and controller instrumentation revisions, the cryogenic supply was successfully throttled by a programmable controller system with appropriate programming. Stable temperature control was ultimately achieved and automated diurnal cycling provided.

  18. Crowdsourcing urban air temperatures from smartphone battery temperatures

    NASA Astrophysics Data System (ADS)

    Overeem, A.; Robinson, J. C. R.; Leijnse, H.; Steeneveld, G. J.; Horn, B. K. P.; Uijlenhoet, R.

    2013-08-01

    Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. A straightforward heat transfer model is employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas.

  19. Controlled-Temperature Hot-Air Gun

    NASA Technical Reports Server (NTRS)

    Munoz, M. C.

    1986-01-01

    Materials that find applications in wind tunnels first tested in laboratory. Hot-Air Gun differs from commercial units in that flow rate and temperature monitored and controlled. With typical compressed-airsupply pressure of 25 to 38 psi (170 to 260 kPa), flow rate and maximum temperature are 34 stdft3/min (0.96 stdm3/min) and 1,090 degrees F (590 degrees C), respectively. Resembling elaborate but carefully regulated hot-air gun, setup used to apply blasts of air temperatures above 1,500 degrees F (815 degrees C) to test specimens.

  20. Air separation with temperature and pressure swing

    DOEpatents

    Cassano, Anthony A.

    1986-01-01

    A chemical absorbent air separation process is set forth which uses a temperature swing absorption-desorption cycle in combination with a pressure swing wherein the pressure is elevated in the desorption stage of the process.

  1. Crowdsourcing urban air temperature measurements using smartphones

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-10-01

    Crowdsourced data from cell phone battery temperature sensors could be used to contribute to improved real-time, high-resolution air temperature estimates in urban areas, a new study shows. Temperature observations in cities are in some cases currently limited to a few weather stations, but there are millions of smartphone users in many cities. The batteries in cell phones have temperature sensors to avoid damage to the phone.

  2. The role of subsurface soil temperature feedbacks in summer surface air temperature variability over East Asia

    NASA Astrophysics Data System (ADS)

    Zhang, J.

    2012-12-01

    Soil temperature, an important component of land surface, can influence the climate through its effects on surface energy and water budgets and resulted changes in regional atmospheric circulation. However, the effects of soil temperature on climate variations have been less discussed. This study investigates the role of subsurface soil temperature feedbacks in influencing summer surface air temperature variability over East Asia by means of regional climate model (RCM) simulations. For this aim, two long-term simulations with and without subsurface soil temperature feedbacks are performed with the Weather Research and Forecasting (WRF) model. From our investigation, it is evident that subsurface soil temperature feedbacks make a dominant contribution to amplifying summer surface air temperature variability over the arid/semi-arid regions. Further analysis reveals that subsurface soil temperature exhibits an asymmetric effect on summer daytime and nighttime surface air temperature variability, with a stronger effect on daily minimum temperature variability than that of daily maximum temperature variability. This study provides the first RCM-based demonstration that subsurface soil temperature feedbacks play an important role in influencing climate variability over East Asia, such as summer surface air temperature. In the meanwhile, the model bias should be recognized. The results achieved by this study thus need to be further confirmed in a multi-model framework to eliminate the model dependence.

  3. Muon production in extended air shower simulations.

    PubMed

    Pierog, T; Werner, K

    2008-10-24

    Whereas air shower simulations are very valuable tools for interpreting cosmic ray data, there is a long-standing problem: it is difficult to accommodate at the same time the longitudinal development of air showers and the number of muons measured on the ground. Using a new hadronic interaction model (EPOS) in air shower simulations produces much more muons, in agreement with results from the HiRes-MIA experiment. We find that this is mainly due to a better description of (anti) baryon production in hadronic interactions. This is an aspect of air shower physics which has been neglected so far. PMID:18999734

  4. Nowcasting daily minimum air and grass temperature

    NASA Astrophysics Data System (ADS)

    Savage, M. J.

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient ( b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  5. Nowcasting daily minimum air and grass temperature.

    PubMed

    Savage, M J

    2016-02-01

    Site-specific and accurate prediction of daily minimum air and grass temperatures, made available online several hours before their occurrence, would be of significant benefit to several economic sectors and for planning human activities. Site-specific and reasonably accurate nowcasts of daily minimum temperature several hours before its occurrence, using measured sub-hourly temperatures hours earlier in the morning as model inputs, was investigated. Various temperature models were tested for their ability to accurately nowcast daily minimum temperatures 2 or 4 h before sunrise. Temperature datasets used for the model nowcasts included sub-hourly grass and grass-surface (infrared) temperatures from one location in South Africa and air temperature from four subtropical sites varying in altitude (USA and South Africa) and from one site in central sub-Saharan Africa. Nowcast models used employed either exponential or square root functions to describe the rate of nighttime temperature decrease but inverted so as to determine the minimum temperature. The models were also applied in near real-time using an open web-based system to display the nowcasts. Extrapolation algorithms for the site-specific nowcasts were also implemented in a datalogger in an innovative and mathematically consistent manner. Comparison of model 1 (exponential) nowcasts vs measured daily minima air temperatures yielded root mean square errors (RMSEs) <1 °C for the 2-h ahead nowcasts. Model 2 (also exponential), for which a constant model coefficient (b = 2.2) was used, was usually slightly less accurate but still with RMSEs <1 °C. Use of model 3 (square root) yielded increased RMSEs for the 2-h ahead comparisons between nowcasted and measured daily minima air temperature, increasing to 1.4 °C for some sites. For all sites for all models, the comparisons for the 4-h ahead air temperature nowcasts generally yielded increased RMSEs, <2.1 °C. Comparisons for all model nowcasts of the daily grass

  6. Temperature Tunable Air-Gap Etalon Filter

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.; Stephen, Mark A.; Lunt, David L.

    1998-01-01

    We report on experimental measurements of a temperature tuned air-gap etalon filter. The filter exhibits temperature dependent wavelength tuning of 54 pm/C. It has a nominal center wavelength of 532 nm. The etalon filter has a 27 pm optical bandpass and 600 pm free spectral range (finesse approximately 22). The experimental results are in close agreement with etalon theory.

  7. GENERATION OF FUMES SIMULATING PARTICULATE AIR POLLUTANTS

    EPA Science Inventory

    The report describes techniques developed for generating large quantities of reproducible, stable, inorganic, fine-particle aerosol fumes. These fumes simulated particulate air pollutants emitted from power generation, basic oxygen furnaces, electric arc furnaces, and zinc smelti...

  8. Undulator Hall Air Temperature Fault Scenarios

    SciTech Connect

    Sevilla, J.; Welch, J.; /SLAC

    2010-11-17

    Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about {+-}2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.

  9. Modeling monthly mean air temperature for Brazil

    NASA Astrophysics Data System (ADS)

    Alvares, Clayton Alcarde; Stape, José Luiz; Sentelhas, Paulo Cesar; de Moraes Gonçalves, José Leonardo

    2013-08-01

    Air temperature is one of the main weather variables influencing agriculture around the world. Its availability, however, is a concern, mainly in Brazil where the weather stations are more concentrated on the coastal regions of the country. Therefore, the present study had as an objective to develop models for estimating monthly and annual mean air temperature for the Brazilian territory using multiple regression and geographic information system techniques. Temperature data from 2,400 stations distributed across the Brazilian territory were used, 1,800 to develop the equations and 600 for validating them, as well as their geographical coordinates and altitude as independent variables for the models. A total of 39 models were developed, relating the dependent variables maximum, mean, and minimum air temperatures (monthly and annual) to the independent variables latitude, longitude, altitude, and their combinations. All regression models were statistically significant ( α ≤ 0.01). The monthly and annual temperature models presented determination coefficients between 0.54 and 0.96. We obtained an overall spatial correlation higher than 0.9 between the models proposed and the 16 major models already published for some Brazilian regions, considering a total of 3.67 × 108 pixels evaluated. Our national temperature models are recommended to predict air temperature in all Brazilian territories.

  10. Montecarlo simulation of photon induced air showers.

    NASA Astrophysics Data System (ADS)

    D'Ettorre Piazzoli, B.; di Sciascio, G.

    The EPAS code (Electron Photon induced Air Showers) is a three dimensional Montecarlo simulation developed to study the properties of extensive air showers generated by the interaction of high energy photons (or electrons) in the atmosphere. Results of the present simulation concern the longitudinal, lateral, temporal and angular distributions of electrons in atmospheric cascades initiated by photons of energies up to 100 TeV.

  11. Solar Eclipse Effect on Shelter Air Temperature

    NASA Technical Reports Server (NTRS)

    Segal, M.; Turner, R. W.; Prusa, J.; Bitzer, R. J.; Finley, S. V.

    1996-01-01

    Decreases in shelter temperature during eclipse events were quantified on the basis of observations, numerical model simulations, and complementary conceptual evaluations. Observations for the annular eclipse on 10 May 1994 over the United States are presented, and these provide insights into the temporal and spatial changes in the shelter temperature. The observations indicated near-surface temperature drops of as much as 6 C. Numerical model simulations for this eclipse event, which provide a complementary evaluation of the spatial and temporal patterns of the temperature drops, predict similar decreases. Interrelationships between the temperature drop, degree of solar irradiance reduction, and timing of the peak eclipse are also evaluated for late spring, summer, and winter sun conditions. These simulations suggest that for total eclipses the drops in shelter temperature in midlatitudes can be as high as 7 C for a spring morning eclipse.

  12. Terminal area air traffic control simulation

    NASA Technical Reports Server (NTRS)

    1977-01-01

    To study the impact of advanced aeronautical technologies on operations to and from terminal airports, a computer model of air traffic movements was developed. The advantages of fast-time simulation are discussed, and the arrival scheduling and flight simulation are described. A New York area study, user's guide, and programmer's guide are included.

  13. SPCZ and air surface temperature in the south-central Pacific in CMIP5 simulations and a forced 50 km downscaling: changes in RCP4.5 and RCP8.5 vs historical period

    NASA Astrophysics Data System (ADS)

    Hopuare, Marania; Pontaud, Marc; Céron, Jean-Pierre; Déqué, Michel

    2013-04-01

    The South Pacific Convergence Zone (SPCZ) is a key feature in the South Pacific climate. Its orientation, intensity and variability directly impacts the population's water resource as well as risks of floods and provides an ideal place for perturbations to develop and grow into depressions or even tropical cyclones. In this study, we focus on the changes in precipitation and surface air temperature, with CMIP5 models and a forced 50km downscaled simulation including a bias correction of SST. The reference period 1960-2005 has been chosen from the historical simulations of CMIP5 models in order to evaluate the change implied by two scenarios of the twenty-first century : RCP8.5 and RCP4.5. The three thirty year periods 2006-2037, 2038-2069, 2070-2100, are analyzed to highlight the transition, for the two austral seasons, summer and winter. We confirm the double ITCZ bias in the CMIP5 simulations (Brown et al, 2012, Clim. Dyn.) which is slightly improved in the forced simulation while the amount of precipitations is increased. It turns out that a westward contraction of the simulated SPCZ occurs along the twenty-first century, more significant in the RCP8.5. Finally the SPCZ leaves the eastern Polynesian islands (the Gambiers archipelago ) suggesting a drier climate during the austral summer by the end of the twenty-first century. This move is not obvious in the forced simulation and it makes sense regarding the global coupled model CNRM-CM5, which SSTs (after bias correction) are used to produce the forced simulation. Indeed, the departure of the SPCZ is not as pronounced as it is in the majority of models. The surface air temperature increases in the whole south Pacific but the warming is more intense over the equatorial cold tongue and persistent all year long, it reaches more than 3°C by the end of the twenty-first century under the RCP8.5 scenario. The forced simulation exhibits a similar but smoother pattern and the anomalies are somewhat reduced. People

  14. Computationally Lightweight Air-Traffic-Control Simulation

    NASA Technical Reports Server (NTRS)

    Knight, Russell

    2005-01-01

    An algorithm for computationally lightweight simulation of automated air traffic control (ATC) at a busy airport has been derived. The algorithm is expected to serve as the basis for development of software that would be incorporated into flight-simulator software, the ATC component of which is not yet capable of handling realistic airport loads. Software based on this algorithm could also be incorporated into other computer programs that simulate a variety of scenarios for purposes of training or amusement.

  15. 40 CFR 91.309 - Engine intake air temperature 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 temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  16. 40 CFR 91.309 - Engine intake air temperature 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 temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  17. 40 CFR 91.309 - Engine intake air temperature 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 temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  18. 40 CFR 91.309 - Engine intake air temperature 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 temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  19. 40 CFR 91.309 - Engine intake air temperature 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 temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must...

  20. Effect of Ambient Design Temperature on Air-Cooled Binary Plant Output

    SciTech Connect

    Dan Wendt; Greg Mines

    2011-10-01

    Air-cooled binary plants are designed to provide a specified level of power production at a particular air temperature. Nominally this air temperature is the annual mean or average air temperature for the plant location. This study investigates the effect that changing the design air temperature has on power generation for an air-cooled binary plant producing power from a resource with a declining production fluid temperature and fluctuating ambient temperatures. This analysis was performed for plants operating both with and without a geothermal fluid outlet temperature limit. Aspen Plus process simulation software was used to develop optimal air-cooled binary plant designs for specific ambient temperatures as well as to rate the performance of the plant designs at off-design operating conditions. Results include calculation of annual and plant lifetime power generation as well as evaluation of plant operating characteristics, such as improved power generation capabilities during summer months when electric power prices are at peak levels.

  1. Simulator Of Rain In Flowing Air

    NASA Technical Reports Server (NTRS)

    Clayton, Richard M.; Cho, Young I.; Shakkottai, Parthasarathy; Back, Lloyd H.

    1989-01-01

    Report describes relatively inexpensive apparatus that creates simulated precipitation from drizzle to heavy rain in flowing air. Small, positive-displacement pump and water-injecting device positioned at low-airspeed end of converging section of wind tunnel 10 in. in diameter. Drops injected by array entrained in flow of air as it accelerates toward narrower outlet, 15 in. downstream. Outlet 5 in. in diameter.

  2. Simulation of a hydraulic air ingestion process

    SciTech Connect

    Chen, F.C.; Golshani, A.

    1981-01-01

    A hydraulic air ingestion process which requires no mechanical moving parts to accomplish air compression but a downward flow of water and operates at nearly isothermal compression mode can be a viable alternative for the noncondensibles disposal of an OTEC open-cycle power system. A computer simulation of the process is presented based on one-dimensional lumped parameter analysis. Results of laboratory-scale experiments were obtained which compared favorably with the analytical results. A sensitivity study which depicts the effects of various parameters upon the applied head of the hydraulic air ingestion process is also presented.

  3. Amino acid-mediated impacts of elevated carbon dioxide and simulated root herbivory on aphids are neutralized by increased air temperatures

    PubMed Central

    Ryalls, James M. W.; Moore, Ben D.; Riegler, Markus; Gherlenda, Andrew N.; Johnson, Scott N.

    2015-01-01

    Changes in host plant quality, including foliar amino acid concentrations, resulting from global climate change and attack from multiple herbivores, have the potential to modify the pest status of insect herbivores. This study investigated how mechanically simulated root herbivory of lucerne (Medicago sativa) before and after aphid infestation affected the pea aphid (Acyrthosiphon pisum) under elevated temperature (eT) and carbon dioxide concentrations (eCO2). eT increased plant height and biomass, and eCO2 decreased root C:N. Foliar amino acid concentrations and aphid numbers increased in response to eCO2, but only at ambient temperatures, demonstrating the ability of eT to negate the effects of eCO2. Root damage reduced aboveground biomass, height, and root %N, and increased root %C and C:N, most probably via decreased biological nitrogen fixation. Total foliar amino acid concentrations and aphid colonization success were higher in plants with roots cut early (before aphid arrival) than those with roots cut late (after aphid arrival); however, this effect was counteracted by eT. These results demonstrate the importance of amino acid concentrations for aphids and identify individual amino acids as being potential factors underpinning aphid responses to eT, eCO2, and root damage in lucerne. Incorporating trophic complexity and multiple climatic factors into plant–herbivore studies enables greater insight into how plants and insects will interact in the future, with implications for sustainable pest control and future crop security. PMID:25403916

  4. Observing System Simulation Experiments for air quality

    NASA Astrophysics Data System (ADS)

    Timmermans, R. M. A.; Lahoz, W. A.; Attié, J.-L.; Peuch, V.-H.; Curier, R. L.; Edwards, D. P.; Eskes, H. J.; Builtjes, P. J. H.

    2015-08-01

    This review paper provides a framework for the application of the Observing System Simulation Experiment (OSSE) methodology to satellite observations of atmospheric constituents relevant for air quality. The OSSEs are experiments used to determine the potential benefit of future observing systems using an existing monitoring or forecasting system and by this can help to define optimal characteristics of future instruments. To this end observations from future instruments are simulated from a model representing the realistic state of the atmosphere and an instrument simulator. The added value of the new observations is evaluated through assimilation into another model or model version and comparison with the simulated true state and a control run. This paper provides an overview of existing air quality OSSEs focusing on ozone, CO and aerosol. Using illustrative examples from these studies we present the main elements of an air quality OSSE and associated requirements based on evaluation of the existing studies and experience within the meteorological community. The air quality OSSEs performed hitherto provide evidence of their usefulness for evaluation of future observations although most studies published do not meet all the identified requirements. Especially the evaluation of the OSSE set-up requires more attention; the differences between the assimilation model and the simulated truth should approximate differences between models and real observations. Although this evaluation is missing in many studies, it is required to ensure realistic results. Properly executed air quality OSSEs are a valuable and cost effective tool to space agencies and instrument builders when applied at the start of the development stage to ensure future observations provide added value to users of Earth Observation data.

  5. 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.

  6. Trends in Surface Temperature from AIRS.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.

    2014-12-01

    To address possible causes of the current hiatus in the Earth's global temperature we investigate the trends and variability in the surface temperature using retrievals obtained from the measurements by the Atmospheric Infrared Sounder (AIRS) and its companion instrument, the Advanced Microwave Sounding Unit (AMSU), onboard of Aqua spacecraft in 2002-2014. The data used are L3 monthly means on a 1x1degree spatial grid. We separate the land and ocean temperatures, as well as temperatures in Artic, Antarctic and desert regions. We find a monotonic positive trend for the land temperature but not for the ocean temperature. The difference in the regional trends can help to explain why the global surface temperature remains almost unchanged but the frequency of occurrence of the extreme events increases under rising anthropogenic forcing. The results are compared with the model studies. This work was supported by the Jet Propulsion Laboratory of the California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  7. CFD simulation research on residential indoor air quality.

    PubMed

    Yang, Li; Ye, Miao; He, Bao-Jie

    2014-02-15

    Nowadays people are excessively depending on air conditioning to create a comfortable indoor environment, but it could cause some health problems in a long run. In this paper, wind velocity field, temperature field and air age field in a bedroom with wall-hanging air conditioning running in summer are analyzed by CFD numerical simulation technology. The results show that wall-hanging air conditioning system can undertake indoor heat load and conduct good indoor thermal comfort. In terms of wind velocity, air speed in activity area where people sit and stand is moderate, most of which cannot feel wind flow and meet the summer indoor wind comfort requirement. However, for air quality, there are local areas without ventilation and toxic gases not discharged in time. Therefore it is necessary to take effective measures to improve air quality. Compared with the traditional measurement method, CFD software has many advantages in simulating indoor environment, so it is hopeful for humans to create a more comfortable, healthy living environment by CFD in the future. PMID:24365517

  8. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  9. 40 CFR 89.325 - Engine intake air temperature 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 temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  10. 40 CFR 89.325 - Engine intake air temperature 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 temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  11. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  12. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  13. 40 CFR 89.325 - Engine intake air temperature 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 temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  14. 40 CFR 89.325 - Engine intake air temperature 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 temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  15. 40 CFR 89.325 - Engine intake air temperature 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 temperature... Test Equipment Provisions § 89.325 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 122 cm of the engine. The measurement location must be made...

  16. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  17. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine....

  18. Increased Air Temperature during Simulated Autumn Conditions Does Not Increase Photosynthetic Carbon Gain But Affects the Dissipation of Excess Energy in Seedlings of the Evergreen Conifer Jack Pine1[OA

    PubMed Central

    Busch, Florian; Hüner, Norman P.A.; Ensminger, Ingo

    2007-01-01

    Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack pine (Pinus banksiana) in controlled environments during a simulated summer-autumn transition under natural conditions and conditions with altered air temperature and photoperiod. Using a factorial design, we dissected the effects of daylength and temperature. Control plants were grown at either warm summer conditions with 16-h photoperiod and 22°C or conditions representing a cool autumn with 8 h/7°C. To assess the impact of photoperiod and temperature on photosynthesis and energy dissipation, plants were also grown under either cold summer (16-h photoperiod/7°C) or warm autumn conditions (8-h photoperiod/22°C). Photosynthetic gas exchange was affected by both daylength and temperature. Assimilation and respiration rates under warm autumn conditions were only about one-half of the summer values but were similar to values obtained for cold summer and natural autumn treatments. In contrast, photosynthetic efficiency was largely determined by temperature but not by daylength. Plants of different treatments followed different strategies for dissipating excess energy. Whereas in the warm summer treatment safe dissipation of excess energy was facilitated via zeaxanthin, in all other treatments dissipation of excess energy was facilitated predominantly via increased aggregation of the light-harvesting complex of photosystem II. These differences were accompanied by a lower deepoxidation state and larger amounts of β-carotene in the warm autumn treatment as well as by changes in

  19. Prediction of air temperature in the aircraft cabin under different operational conditions

    NASA Astrophysics Data System (ADS)

    Volavý, F.; Fišer, J.; Nöske, I.

    2013-04-01

    This paper deals with the prediction of the air temperature in the aircraft cabin by means of Computational Fluid Dynamics. The simulations are performed on the CFD model which is based on geometry and cabin interior arrangement of the Flight Test Facility (FTF) located at Fraunhofer IBP, Germany. The experimental test flights under three different cabin temperatures were done in FTF and the various data were gathered during these flights. Air temperature in the cabin was measured on probes located near feet, torso and head of each passenger and also surface temperature and air temperature distributed from inlets were measured. The data were firstly analysed in order to obtain boundary conditions for cabin surfaces and inlets. Then the results of air temperature from the simulations were compared with measured data. The suitability and accuracy of the CFD approach for temperature prediction is discussed.

  20. Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures

    NASA Astrophysics Data System (ADS)

    Cowtan, Kevin; Hausfather, Zeke; Hawkins, Ed; Jacobs, Peter; Mann, Michael E.; Miller, Sonya K.; Steinman, Byron A.; Stolpe, Martin B.; Way, Robert G.

    2015-08-01

    The level of agreement between climate model simulations and observed surface temperature change is a topic of scientific and policy concern. While the Earth system continues to accumulate energy due to anthropogenic and other radiative forcings, estimates of recent surface temperature evolution fall at the lower end of climate model projections. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. Applying the methodology of the HadCRUT4 record to climate model temperature fields accounts for 38% of the discrepancy in trend between models and observations over the period 1975-2014.

  1. Compression-ignition Engine Performance at Altitudes and at Various Air Pressures and Temperatures

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H

    1937-01-01

    Engine test results are presented for simulated altitude conditions. A displaced-piston combustion chamber on a 5- by 7-inch single cylinder compression-ignition engine operating at 2,000 r.p.m. was used. Inlet air temperature equivalent to standard altitudes up to 14,000 feet were obtained. Comparison between performance at altitude of the unsupercharged compression-ignition engine compared favorably with the carburetor engine. Analysis of the results for which the inlet air temperature, inlet air pressure, and inlet and exhaust pressure were varied indicates that engine performance cannot be reliably corrected on the basis of inlet air density or weight of air charge. Engine power increases with inlet air pressure and decreases with inlet air temperatures very nearly as straight line relations over a wide range of air-fuel ratios. Correction factors are given.

  2. Sensitivity of New England Stream Temperatures to Air Temperature and Precipitation Under Projected Climate

    NASA Astrophysics Data System (ADS)

    Huang, T.; Samal, N. R.; Wollheim, W. M.; Stewart, R. J.; Zuidema, S.; Prousevitch, A.; Glidden, S.

    2015-12-01

    The thermal response of streams and rivers to changing climate will influence aquatic habitat. This study examines the impact that changing climate has on stream temperatures in the Merrimack River, NH/MA USA using the Framework for Aquatic Modeling in the Earth System (FrAMES), a spatially distributed river network model driven by air temperature, air humidity, wind speed, precipitation, and solar radiation. Streamflow and water temperatures are simulated at a 45-second (latitude x longitude) river grid resolution for 135 years under historical and projected climate variability. Contemporary streamflow (Nash-Sutcliffe Coefficient = 0.77) and river temperatures (Nash-Sutcliffe Coefficient = 0.89) matched at downstream USGS gauge data well. A suite of model runs were made in combination with uniformly increased daily summer air temperatures by 2oC, 4 oC and 6 oC as well as adjusted precipitation by -40%, -30%, -20%, -10% and +10% as a sensitivity analysis to explore a broad range of potential future climates. We analyzed the summer stream temperatures and the percent of river length unsuitable for cold to warm water fish habitats. Impacts are greatest in large rivers due to the accumulation of river temperature warming throughout the entire river network. Cold water fish (i.e. brook trout) are most strongly affected while, warm water fish (i.e. largemouth bass) aren't expected to be impacted. The changes in stream temperatures under various potential climate scenarios will provide a better understanding of the specific impact that air temperature and precipitation have on aquatic thermal regimes and habitat.

  3. Air temperature variation across the seed cotton dryer mixpoint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eighteen tests were conducted in six gins in the fall of 2008 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the...

  4. Possible Economies in Air-Conditioning by Accepting Temperature Swings.

    ERIC Educational Resources Information Center

    Loudon, A. G.; Petherbridge, P.

    Public building air conditioning systems, which use constant and varying heat and cooling loads, are compared and investigated. Experiments indicated that constant temperature controls based on outside air temperature alone were inefficient. Ventilating a building with outside air and the methods of doing so are cited as being the most economical…

  5. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  6. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  7. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  8. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  9. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  10. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  11. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  12. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  13. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  14. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  15. AIR TEMPERATURE DISTRIBUTION IN SEED COTTON DRYING SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ten tests were conducted in the fall of 2007 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the airflow ductwork...

  16. 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.

  17. Autoignition of hydrogen and air using direct numerical simulation

    NASA Astrophysics Data System (ADS)

    Doom, Jeffrey; Mahesh, Krishnan

    2008-11-01

    Direct numerical simulation (DNS) is used to study to auto--ignition in laminar vortex rings and turbulent diffusion flames. A novel, all--Mach number algorithm developed by Doom et al (J. Comput. Phys. 2007) is used. The chemical mechanism is a nine species, nineteen reaction mechanism for H2 and Air from Mueller at el (Int. J. Chem. Kinet. 1999). The vortex ring simulations inject diluted H2 at ambient temperature into hot air, and study the effects of stroke ratio, air to fuel ratio and Lewis number. At smaller stroke ratios, ignition occurs in the wake of the vortex ring and propagates into the vortex core. At larger stroke ratios, ignition occurs along the edges of the trailing column before propagating towards the vortex core. The turbulent diffusion flame simulations are three--dimensional and consider the interaction of initially isotropic turbulence with an unstrained diffusion flame. The simulations examine the nature of distinct ignition kernels, the relative roles of chemical reactions, and the relation between the observed behavior and laminar flames and the perfectly stirred reactor problem. These results will be discussed.

  18. [Simulation and air-conditioning in the nose].

    PubMed

    Keck, T; Lindemann, J

    2010-05-01

    Heating and humidification of the respiratory air are the main functions of the nasal airways in addition to cleansing and olfaction. Optimal nasal air conditioning is mandatory for an ideal pulmonary gas exchange in order to avoid dessication and adhesion of the alveolar capillary bed. The complex three-dimensional anatomical structure of the nose makes it impossible to perform detailed in vivo studies on intranasal heating and humidification within the entire nasal airways applying various technical set-ups. The main problem of in vivo temperature and humidity measurements is a poor spatial and time resolution. Therefore, in vivo measurements are feasible to a restricted extent, only providing single temperature values as the complete nose is not entirely accessible. Therefore, data on the overall performance of the nose are only based on one single measurement within each nasal segment. In vivo measurements within the entire nose are not feasible. These serious technical issues concerning in vivo measurements led to a large number of numerical simulation projects in the last few years providing novel information about the complex functions of the nasal airways. In general, numerical simulations only calculate predictions in a computational model, e. g. realistic nose model, depending on the setting of the boundary conditions. Therefore, numerical simulations achieve only approximations of a possible real situation. The aim of this report is the synopsis of the technical expertise on the field of in vivo nasal air conditioning, the novel information of numerical simulations and the current state of knowledge on the influence of nasal and sinus surgery on nasal air conditioning. PMID:20352565

  19. Simulation of air velocity in a vertical perforated air distributor

    NASA Astrophysics Data System (ADS)

    Ngu, T. N. W.; Chu, C. M.; Janaun, J. A.

    2016-06-01

    Perforated pipes are utilized to divide a fluid flow into several smaller streams. Uniform flow distribution requirement is of great concern in engineering applications because it has significant influence on the performance of fluidic devices. For industrial applications, it is crucial to provide a uniform velocity distribution through orifices. In this research, flow distribution patterns of a closed-end multiple outlet pipe standing vertically for air delivery in the horizontal direction was simulated. Computational Fluid Dynamics (CFD), a tool of research for enhancing and understanding design was used as the simulator and the drawing software SolidWorks was used for geometry setup. The main purpose of this work is to establish the influence of size of orifices, intervals between outlets, and the length of tube in order to attain uniformity of exit flows through a multi outlet perforated tube. However, due to the gravitational effect, the compactness of paddy increases gradually from top to bottom of dryer, uniform flow pattern was aimed for top orifices and larger flow for bottom orifices.

  20. Robust Comparison of Climate Models with Observations Using Blended Land Air and Ocean Sea Surface Temperatures

    NASA Astrophysics Data System (ADS)

    Hausfather, Z.; Jacobs, P.; Cowtan, K.; Hawkins, E.; Mann, M. E.; Miller, S. K.; Steinman, B. A.; Way, R. G.; Stolpe, M.

    2015-12-01

    Model-observation comparisons provide an important test of climate models' ability to realistically simulate the transient evolution of the system. A great deal of attention has recently focused on the so-called "hiatus" period of the past ~15 years, when estimates of recent surface temperature evolution fall at the lower end of climate model projections. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. We discuss the magnitude of these biases, and their implications for the evaluation of climate model performance over the "hiatus" period and the full instrumental record.

  1. 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

  2. 40 CFR 90.309 - Engine intake air temperature 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 temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  3. 40 CFR 90.309 - Engine intake air temperature 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 temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  4. 40 CFR 90.309 - Engine intake air temperature 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 temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  5. 40 CFR 90.309 - Engine intake air temperature 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 temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  6. 40 CFR 90.309 - Engine intake air temperature 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 temperature... Emission Test Equipment Provisions § 90.309 Engine intake air temperature measurement. (a) The measurement...) The temperature measurements must be accurate to within ±2 °C....

  7. Simulating the moderating effect of a lake on downwind temperatures

    NASA Technical Reports Server (NTRS)

    Bill, R. G., Jr.; Chen, E.; Sutherland, R. A.; Bartholic, J. F.

    1979-01-01

    A steady-state, two-dimensional numerical model is used to simulate air temperatures and humidity downwind of a lake at night. Thermal effects of the lake were modelled for the case of moderate and low surface winds under the cold-air advective conditions that occur following the passage of a cold front. Surface temperatures were found to be in good agreement with observations. A comparison of model results with thermal imagery indicated the model successfully predicts the downwind distance for which thermal effects due to the lake are significant.

  8. Stochastic Human Exposure and Dose Simulation for Air Toxics

    EPA Science Inventory

    The Stochastic Human Exposure and Dose Simulation model for Air Toxics (SHEDS-AirToxics) is a multimedia, multipathway population-based exposure and dose model for air toxics developed by the US EPA's National Exposure Research Laboratory (NERL). SHEDS-AirToxics uses a probabili...

  9. INDOOR AIR QUALITY AND INHALATION EXPOSURE - SIMULATION TOOL KIT

    EPA Science Inventory

    A Microsoft Windows-based indoor air quality (IAQ) simulation software package is presented. Named Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure, or IAQX for short, this package complements and supplements existing IAQ simulation programs and is desi...

  10. Some Factors Influencing Air Force Simulator Training Effectiveness. Technical Report.

    ERIC Educational Resources Information Center

    Caro, Paul W.

    A study of U.S. Air Force simulator training was conducted to identify factors that influence the effectiveness of such training and to learn how its effectiveness is being determined. The research consisted of a survey of ten representative Air Force simulator training programs and a review of the simulator training research literature. A number…

  11. On extreme rainfall intensity increases with air temperature

    NASA Astrophysics Data System (ADS)

    Molnar, Peter; Fatichi, Simone; Paschalis, Athanasios; Gaal, Ladislav; Szolgay, Jan; Burlando, Paolo

    2016-04-01

    trained to reproduce the rainfall intensity-air temperature relations observed in data at high temporal resolutions. We believe that the observed relationships of rainfall intensity to air temperature should be reproducible by stochastic rainfall models if they are to be used for climate change impact studies which require high temporal resolution simulation, e.g. for urban drainage analysis, flash flood generation, etc. Molnar, P., Fatichi, S., Gaal, L., Szolgay, J., and Burlando, P.: Storm type effects on super Clausius-Clapeyron scaling of intense rainstorm properties with air temperature, Hydrol. Earth Syst. Sci., 19, 1753-1766, doi: 10.5194/hess-19-1753-2015, 2015. Paschalis A., Molnar P., Fatichi S., and Burlando, P.: On temporal stochastic modeling of precipitation, nesting models across scales, Adv. Water Resour., 63, 152-166, doi:10.1016/j.advwatres.2013.11.006, 2014. Westra, S., Fowler, H.J., Evans, J.P., Alexander, L.V., Berg, P., Johnson, F., Kendon, E.J., Lenderink, G., and Roberts, N.M.: Future changes to the intensity and frequency of short-duration extreme rainfall, Rev. Geophys., 52, 522-555, doi:10.1002/2014RG000464, 2014.

  12. Modelling and simulation of air-conditioning cycles

    NASA Astrophysics Data System (ADS)

    Rais, Sandi; Kadono, Yoshinori; Murayama, Katsunori; Minakuchi, Kazuya; Takeuchi, Hisae; Hasegawa, Tatsuya

    2016-05-01

    The heat-pump cycle for air conditioning was investigated both numerically and experimentally by evaluating the coefficient of performance (COP) under Japanese Industrial Standard (JIS B 8619:1999) and ANSI/AHRI standard 750-2007 operating conditions. We used two expansion valve coefficients Cv_{(\\varphi )} = 0.12 for standard operating conditions (Case 1) approaching 1.3 MPa at high pressure and 0.2 MPa at low pressure, and Cv_{(\\varphi )} = 0.06 namely poor operating conditions (Case 2). To improve the performance of the air conditioner, we compared the performance for two outside air temperatures, 35 and 40 °C (Case 3). The simulation and experiment comparison resulted the decreasing of the COP for standard operating condition is equal to 14 %, from 3.47 to 2.95 and a decrease of the cooling capacity is equal to 18 %, from 309.72 to 253.53 W. This result was also occurred in poor operating condition which the COP was superior at 35 °C temperature.

  13. Modeling subcanopy incoming longwave radiation to seasonal snow using air and tree trunk temperatures

    NASA Astrophysics Data System (ADS)

    Webster, Clare; Rutter, Nick; Zahner, Franziska; Jonas, Tobias

    2016-02-01

    Data collected at three Swiss alpine forested sites over a combined 11 year period were used to evaluate the role of air temperature in modeling subcanopy incoming longwave radiation to the snow surface. Simulated subcanopy incoming longwave radiation is traditionally partitioned into that from the sky and that from the canopy, i.e., a two-part model. Initial uncertainties in predicting longwave radiation using the two-part model resulted from vertical differences in measured air temperature. Above-canopy (35 m) air temperatures were higher than those within (10 m) and below (2 m) canopy throughout four snow seasons (December-April), demonstrating how the forest canopy can act as a cold sink for air. Lowest model root-mean-square error (RMSE) was using above-canopy air temperature. Further investigation of modeling subcanopy longwave radiation using above-canopy air temperature showed underestimations, particularly during periods of high insolation. In order to explicitly account for canopy temperatures in modeling longwave radiation, the two-part model was improved by incorporating a measured trunk view component and trunk temperature. Trunk temperature measurements were up to 25°C higher than locally measured air temperatures. This three-part model reduced the RMSE by up to 7.7 W m-2 from the two-part air temperature model at all sensor positions across the 2014 snowmelt season and performed particularly well during periods of high insolation when errors from the two-part model were up to 40 W m-2. A parameterization predicting tree trunk temperatures using measured air temperature and incoming shortwave radiation demonstrate a simple method that can be applied to provide input to the three-part model across midlatitude coniferous forests.

  14. Estimation of Surface Air Temperature from MODIS 1km Resolution Land Surface Temperature Over Northern China

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

    2010-01-01

    Surface air temperature is a critical variable to describe the energy and water cycle of the Earth-atmosphere system and is a key input element for hydrology and land surface models. It is a very important variable in agricultural applications and climate change studies. This is a preliminary study to examine statistical relationships between ground meteorological station measured surface daily maximum/minimum air temperature and satellite remotely sensed land surface temperature from MODIS over the dry and semiarid regions of northern China. Studies were conducted for both MODIS-Terra and MODIS-Aqua by using year 2009 data. Results indicate that the relationships between surface air temperature and remotely sensed land surface temperature are statistically significant. The relationships between the maximum air temperature and daytime land surface temperature depends significantly on land surface types and vegetation index, but the minimum air temperature and nighttime land surface temperature has little dependence on the surface conditions. Based on linear regression relationship between surface air temperature and MODIS land surface temperature, surface maximum and minimum air temperatures are estimated from 1km MODIS land surface temperature under clear sky conditions. The statistical errors (sigma) of the estimated daily maximum (minimum) air temperature is about 3.8 C(3.7 C).

  15. Simulation study of plane motion of air cushion vehicle

    NASA Astrophysics Data System (ADS)

    Zhao, Shu-Qin; Shi, Xiao-Cheng; Shi, Yi-Long; Bian, Xin-Qian

    2003-12-01

    This research is on horizontal plane motion equations of Air Cushion Vehicle (ACV) and its simulation. To investigate this, a lot of simulation study including ACV’s voyage and turning performance has been done. It was found that the voyage simulation results were accorded with ACV own characteristic and turning simulation results were accorded with USA ACV’s movement characteristic basically.

  16. Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

    NASA Astrophysics Data System (ADS)

    Wang, K.; Li, Y.; Wang, X.; Yuan, M.

    2013-12-01

    Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and

  17. Simulation model finned water-air-coil withoutcondensation

    SciTech Connect

    Wetter, Michael

    1999-01-01

    A simple simulation model of a finned water-to- air coil without condensation is presented. The model belongs to a collection of simulation models that allows eficient computer simulation of heating, ventilation, and air-conditioning (HVAC) systems. The main emphasis of the models is short computation time and use of input data that are known in the design process of an HVAC system. The target of the models is to describe the behavior of HVAC components in the part load operation mode, which is becoming increasingly important for energy efficient HVAC systems. The models are intended to be used for yearly energy calculation or load calculation with time steps of about 10 minutes or larger. Short-time dynamic effects, which are of interest for different aspects of control performance, are neglected. The part load behavior of the coil is expressed in terms of the nominal condition and the dimensionless variation of the heat transfer with change of mass flow and temperature on the water side and the air side. The effectiveness- NTU relations are used to parametrize the convective heat transfer at nominal conditions and to compute the part load conditions. Geometrical data for the coil are not required, The calculation of the convective heat transfer coefficients at nominal conditions is based on the ratio of the air side heat transfer coefficients multiplied by the fin eficiency and divided by the water side heat transfer coefficient. In this approach, the only geometrical information required are the cross section areas, which are needed to calculate the~uid velocities. The formulas for estimating this ratio are presented. For simplicity the model ignores condensation. The model is static and uses only explicit equations. The explicit formulation ensures short computation time and numerical stability. This allows using the model with sophisticated engineering methods such as automatic system optimization. The paper fully outlines the algorithm description and its

  18. Dynamics of Cold-Air Pool Breakup: Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Lareau, N.; Horel, J.

    2013-12-01

    Persistent cold-air pools (CAPs) impact urban mountain valleys during the winter leading to prolonged episodes of unhealthy air quality. One associated scientific challenge is accurately forecasting the breakup of these CAPs. For example, there is often uncertainty regarding the interaction of passing weather systems with the stratification within a valley. Will the disturbance be sufficient to destroy the CAP, or will the CAP persist for many more days bringing continued elevated levels of pollution? To address these questions this study examines the dynamical processes that affect the time scale and character of CAP breakup. To do so we use idealized large eddy simulations (LES) to examine the sensitivity of CAP removal to variations in wind, topography, and stratification. The simulations are based on field observations from the Persistent Cold-Air Pool Study (PCAPS). Results indicate that the upstream terrain-flow interaction is important in controlling both the timescale and structure of the CAP breakup. For example, when the flow plunges over the confining topography it leads to enhanced turbulent mixing, CAP displacement, and shorter timescales for complete CAP removal. In contrast, when no mountain wave is present the upstream edge of the CAP remains sheltered from the wind-driven mixing and the break-up is first observed over downstream portions of the basin. Meanwhile, changes in the CAP stratification impact internal circulations that develop in response to the imposed wind forcing. These circulations have significance for the distribution of pollution within CAPs. A concise summary of these results will be presented. Snapshot from a simulation of strong winds disrupting a CAP confined between two ridges. Potential temperature (a), vertical velocity (b), and wind speed (c).

  19. Fault diagnosis and temperature sensor recovery for an air-handling unit

    SciTech Connect

    Lee, W.Y.; Shin, D.R.; House, J.M.

    1997-12-31

    The presence of faults and the influence they have on system operation is a real concern in the heating, ventilating, and air-conditioning (HVAC) community. A fault can be defined as an inadmissible or unacceptable property of a system or a component. Unless corrected, faults can lead to increased energy use, shorter equipment life, and uncomfortable and/or unhealthy conditions for building occupants. This paper describes the use of a two-stage artificial neural network for fault diagnosis in a simulated air-handling unit. The stage one neural network is trained to identify the subsystem in which a fault occurs. The stage two neural network is trained to diagnose the specific cause of a fault at the subsystem level. Regression equations for the supply and mixed-air temperatures are obtained from simulation data and are used to compute input parameters to the neutral networks. Simulation results are presented that demonstrate that, after a successful diagnosis of a supply air temperature sensor fault, the recovered estimate of the supply air temperature obtained from the regression equation can be used in a feedback control loop to bring the supply air temperature back to the setpoint value. Results are also presented that illustrate the evolution of the diagnosis of the two-stage artificial neural network from normal operation to various fault modes of operation.

  20. Comparison of MODIS Land Surface Temperature and Air Temperature over the Continental USA Meteorological Stations

    NASA Technical Reports Server (NTRS)

    Zhang, Ping; Bounoua, Lahouari; Imhoff, Marc L.; Wolfe, Robert E.; Thome, Kurtis

    2014-01-01

    The National Land Cover Database (NLCD) Impervious Surface Area (ISA) and MODIS Land Surface Temperature (LST) are used in a spatial analysis to assess the surface-temperature-based urban heat island's (UHIS) signature on LST amplitude over the continental USA and to make comparisons to local air temperatures. Air-temperature-based UHIs (UHIA), calculated using the Global Historical Climatology Network (GHCN) daily air temperatures, are compared with UHIS for urban areas in different biomes during different seasons. NLCD ISA is used to define urban and rural temperatures and to stratify the sampling for LST and air temperatures. We find that the MODIS LST agrees well with observed air temperature during the nighttime, but tends to overestimate it during the daytime, especially during summer and in nonforested areas. The minimum air temperature analyses show that UHIs in forests have an average UHIA of 1 C during the summer. The UHIS, calculated from nighttime LST, has similar magnitude of 1-2 C. By contrast, the LSTs show a midday summer UHIS of 3-4 C for cities in forests, whereas the average summer UHIA calculated from maximum air temperature is close to 0 C. In addition, the LSTs and air temperatures difference between 2006 and 2011 are in agreement, albeit with different magnitude.

  1. Retrieval of air temperatures from crowd-sourced battery temperatures of cell phones

    NASA Astrophysics Data System (ADS)

    Overeem, Aart; Robinson, James; Leijnse, Hidde; Uijlenhoet, Remko; Steeneveld, Gert-Jan; Horn, Berthold K. P.

    2013-04-01

    Accurate air temperature observations are important for urban meteorology, for example to study the urban heat island and adverse effects of high temperatures on human health. The number of available temperature observations is often relatively limited. A new development is presented to derive temperature information for the urban canopy from an alternative source: cell phones. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. Results are presented for Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree Celsius. This shows that monitoring air temperatures employing an Android application holds great promise. Since 75% of the world's population has a cell phone, 20% of the land surface of the earth has cellular telephone coverage, and 500 million devices use the Android operating system, there is a huge potential for measuring air temperatures employing cell phones. This could eventually lead to real-time world-wide temperature maps.

  2. Simulated effects of cropland expansion on seasonal temperatures over China

    NASA Astrophysics Data System (ADS)

    Xiong, Zhe

    Human activities result in deforestation, expansion of cropland, grassland degradation, urbanization and other large-scale land use/cover change; among these, cropland expansion is one of the most important processes. To understand the effects of cropland expansion on seasonal temperatures over China, two 21-year simulations (spanning January 1, 1980-December 31, 2000), using the Regional Integrated Environmental Model System (RIEMS 2.0), were performed. The two simulations comprised current realistic land use/cover patterns and the previous vegetation cover without crop expansion, to investigate the impact of crop expansion on seasonal temperatures over China. The results showed that due to cropland expansion: (1) the most obvious changes occurred in the maximum temperatures, followed by the mean surface air temperatures, and the minimum temperatures were the least affected; (2) the summer mean maximum temperatures decreased in most parts of eastern China, and the temperatures changed significantly in most parts of northeast China, north China and central China (p < 0.05); (3) the surface air temperatures, maximum temperatures and minimum temperatures in summer decreased in the different regions by between -0.03 and -0.76 °C (the greatest temperature changes occurred in southwest China, and the smallest were in northeast China); (4) the net radiation flux and latent heat flux increased, while the sensible flux decreased, when semi-desert vegetation was replaced by dry land crops, in both summer and winter seasons, and the converse occurred when irrigated crops were replaced by dry land crops. In addition, the net radiation flux and sensible heat flux decreased, and the latent heat flux increased when short grass and tall grass were replaced dry land crops, as well as when dry land crops were replaced by irrigated crops.

  3. DEVELOPMENT AND ANALYSIS OF AIR QUALITY MODELING SIMULATIONS FOR HAZARDOUS AIR POLLUTANTS

    EPA Science Inventory

    The concentrations of five hazardous air pollutants were simulated using the Community Multi Scale Air Quality (CMAQ) modeling system. Annual simulations were performed over the continental United States for the entire year of 2001 to support human exposure estimates. Results a...

  4. Associations of endothelial function and air temperature in diabetic subjects

    EPA Science Inventory

    Background and Objective: Epidemiological studies consistently show that air temperature is associated with changes in cardiovascular morbidity and mortality. However, the biological mechanisms underlying the association remain largely unknown. As one index of endothelial functio...

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  6. The influence of air-conditioning on street temperatures in the city of Paris

    NASA Astrophysics Data System (ADS)

    de Munck, C. S.; Pigeon, G.; Masson, V.; Marchadier, C.; Meunier, F.; Tréméac, B.; Merchat, M.

    2010-12-01

    A consequence of urban heat islands in summer is the increased use of air-conditioning during extreme heat events : the use of air-conditioning systems, while cooling the inside of buildings releases waste heat (as latent and sensible heat) in the lower part of the urban atmosphere, hence potentially increasing air street temperatures where the heat is released. This may lead locally to a further increase in air street temperatures, therefore increasing the air cooling demand, while at the same time lowering the efficiency of air-conditioning units. A coupled model consisting of a meso-scale meteorological model (MESO-NH) and an urban energy balance model (TEB) has been implemented with an air-conditioning module and used in combination to real spatialised datasets to understand and quantify potential increases in temperature due to air-conditioning heat releases for the city of Paris . In a first instance, the current types of air-conditioning systems co-existing in the city were simulated (underground chilled water network, wet cooling towers and individual air-conditioning units) to study the effects of latent and sensible heat releases on street temperatures. In a third instance, 2 scenarios were tested to characterise the impacts of likely future trends in air-conditioning equipment in the city : a first scenario for which current heat releases were converted to sensible heat, and a second based on 2030s projections of air-conditioning equipment at the scale of the city. All the scenarios showed an increase in street temperature which, as expected, was greater at night time than day time. For the first two scenarios, this increase in street temperatures was localised at or near the sources of air-conditioner heat releases, while the 2030s air-conditioning scenario impacted wider zones in the city. The amplitude of the increase in temperature varied from 0,25°C to 1°C for the air-conditioning current state, between 0,25°C and 2°C for the sensible heat

  7. Lessons Learned from AIRS: Improved Determination of Surface and Atmospheric Temperatures Using Only Shortwave AIRS Channels

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2011-01-01

    This slide presentation reviews the use of shortwave channels available to the Atmospheric Infrared Sounder (AIRS) to improve the determination of surface and atmospheric temperatures. The AIRS instrument is compared with the Infrared Atmospheric Sounding Interferometer (IASI) on-board the MetOp-A satellite. The objectives of the AIRS/AMSU were to (1) provide real time observations to improve numerical weather prediction via data assimilation, (2) Provide observations to measure and explain interannual variability and trends and (3) Use of AIRS product error estimates allows for QC optimized for each application. Successive versions in the AIRS retrieval methodology have shown significant improvement.

  8. Effect of Initial Mixture Temperature on Flame Speed of Methane-Air, Propane-Air, and Ethylene-Air Mixtures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L

    1952-01-01

    Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.

  9. What is Air? A Standard Model for Combustion Simulations

    SciTech Connect

    Cloutman, L D

    2001-08-01

    Most combustion devices utilize air as the oxidizer. Thus, reactive flow simulations of these devices require the specification of the composition of air as part of the physicochemical input. A mixture of only oxygen and nitrogen often is used, although in reality air is a more complex mixture of somewhat variable composition. We summarize some useful parameters describing a standard model of dry air. Then we consider modifications to include water vapor for creating the desired level of humidity. The ''minor'' constituents of air, especially argon and water vapor, can affect the composition by as much as about 5 percent in the mole fractions.

  10. Computer Simulation for Air-coupled Ultrasonic Testing

    NASA Astrophysics Data System (ADS)

    Yamawaki, H.

    2014-06-01

    Air-coupled ultrasound is used as non-contact ultrasonic testing method. For wider application of air-coupled ultrasonic technique, it is required to know situation of ultrasonic propagation between air and solid. Transmittance of the ultrasonic waves from air to solids is extremely small with 10-5 however it was revealed that, by using computer simulation methods based on the two-stage elastic wave equation in which two independent variables of stress and particle velocity are used, visualization calculation of ultrasonic propagation between air and solid was possible. In this report, the calculation of air-coupled ultrasound using the new Improved-FDM for computer simulation of ultrasonic propagation in solids is shown. Waveforms obtained by 1-dimensional calculation are discussed for principle and performance of the calculation. Visualization of ultrasonic incidence to cylindrical steel pipe is demonstrated as an example to show availability for ultrasonic testing.

  11. 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.

  12. Lightweight simulation of air traffic control using simple temporal networks

    NASA Technical Reports Server (NTRS)

    Knight, Russell

    2005-01-01

    We provide a formulation of the air traffic control problem and a solver for this problem that makes use of temporal constraint networks and simple geometric reasoning. We provide results showing that this approach is practical for realistic simulated problems.

  13. SYSTEMATIC SENSITIVITY ANALYSIS OF AIR QUALITY SIMULATION MODELS

    EPA Science Inventory

    This report reviews and assesses systematic sensitivity and uncertainty analysis methods for applications to air quality simulation models. The discussion of the candidate methods presents their basic variables, mathematical foundations, user motivations and preferences, computer...

  14. Simulating Air Quality Investiga tions with the Programmable Calculator

    ERIC Educational Resources Information Center

    Craig, James C.

    1974-01-01

    Describes ways in which a student might use a programmable calculator to obtain air pollution data for a particular locale and outlines the teacher's role in preparing the Computer Simulated Experimentation. (JR)

  15. 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…

  16. Monte Carlo simulation of photon-induced air showers

    NASA Astrophysics Data System (ADS)

    D'Ettorre Piazzoli, B.; di Sciascio, G.

    1994-05-01

    The EPAS code (Electron Photon-induced Air Showers) is a three-dimensional Monte Carlo simulation developed to study the properties of extensive air showers (EAS) generated by the interaction of high energy photons (or electrons) in the atmosphere. Results of the present simulation concern the longitudinal, lateral, temporal and angular distributions of electrons in atmospheric cascades initiated by photons of energies up to 10^3 TeV.

  17. Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste

    2010-01-01

    AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best

  18. Thermal Gradient Behavior of TBCs Subjected to a Laser Gradient Test Rig: Simulating an Air-to-Air Combat Flight

    NASA Astrophysics Data System (ADS)

    Lima, Rogerio S.; Marple, Basil R.; Marcoux, P.

    2016-01-01

    A computer-controlled laser test rig (using a CO2 laser) offers an interesting alternative to traditional flame-based thermal gradient rigs in evaluating thermal barrier coatings (TBCs). The temperature gradient between the top and back surfaces of a TBC system can be controlled based on the laser power and a forced air back-face cooling system, enabling the temperature history of complete aircraft missions to be simulated. An air plasma spray-deposited TBC was tested and, based on experimental data available in the literature, the temperature gradients across the TBC system (ZrO2-Y2O3 YSZ top coat/CoNiCrAlY bond coat/Inconel 625 substrate) and their respective frequencies during air-to-air combat missions of fighter jets were replicated. The missions included (i) idle/taxi on the runway, (ii) take-off and climbing, (iii) cruise trajectory to rendezvous zone, (iv) air-to-air combat maneuvering, (v) cruise trajectory back to runway, and (vi) idle/taxi after landing. The results show that the TBC thermal gradient experimental data in turbine engines can be replicated in the laser gradient rig, leading to an important tool to better engineer TBCs.

  19. Simulated Data for High Temperature Composite Design

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Abumeri, Galib H.

    2006-01-01

    The paper describes an effective formal method that can be used to simulate design properties for composites that is inclusive of all the effects that influence those properties. This effective simulation method is integrated computer codes that include composite micromechanics, composite macromechanics, laminate theory, structural analysis, and multi-factor interaction model. Demonstration of the method includes sample examples for static, thermal, and fracture reliability for a unidirectional metal matrix composite as well as rupture strength and fatigue strength for a high temperature super alloy. Typical results obtained for a unidirectional composite show that the thermal properties are more sensitive to internal local damage, the longitudinal properties degrade slowly with temperature, the transverse and shear properties degrade rapidly with temperature as do rupture strength and fatigue strength for super alloys.

  20. Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

    NASA Astrophysics Data System (ADS)

    Gladden, H. J.; Liebert, C. H.

    1980-02-01

    The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

  1. Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

    NASA Technical Reports Server (NTRS)

    Gladden, H. J.; Liebert, C. H.

    1980-01-01

    The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

  2. Climatology of upper air temperature in the Eastern Mediterranean region

    NASA Astrophysics Data System (ADS)

    Philandras, C. M.; Nastos, P. T.; Kapsomenakis, I. N.; Repapis, C. C.

    2015-01-01

    The goal of this study is to contribute to the climatology of upper air temperature in the Mediterranean region, during the period 1965-2011. For this purpose, both radiosonde recordings and gridded reanalysis datasets of upper air temperature from National Center for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) were used for seven barometric levels at 850 hPa, 700 hPa, 500 hPa, 300 hPa, 200 hPa, 150 hPa and 100 hPa. Trends and variability of upper air temperature were analyzed on annual and seasonal basis. Further, the impact of atmospheric circulation, by means of correlation between upper air temperature at different barometric levels and specific climatic indices such as Mediterranean Oscillation Index (MOI), North Sea Caspian Pattern Index (NCPI) and North Atlantic Oscillation Index (NAOI), was also quantified. Our findings have given evidence that air temperature is increasing at a higher rate in lower/middle troposphere against upper, and this is very likely due to increasing greenhouse gas concentrations.

  3. Cool Roofs in Guangzhou, China: Outdoor Air Temperature Reductions during Heat Waves and Typical Summer Conditions.

    PubMed

    Cao, Meichun; Rosado, Pablo; Lin, Zhaohui; Levinson, Ronnen; Millstein, Dev

    2015-12-15

    In this paper, we simulate temperature reductions during heat-wave events and during typical summer conditions from the installation of highly reflective "cool" roofs in the Chinese megacity of Guangzhou. We simulate temperature reductions during six of the strongest historical heat-wave events over the past decade, finding average urban midday temperature reductions of 1.2 °C. In comparison, we simulate 25 typical summer weeks between 2004 and 2008, finding average urban midday temperature reductions of 0.8 °C, indicating that air temperature sensitivity to urban albedo in Guangzhou varies with meteorological conditions. We find that roughly three-fourths of the variance in air temperature reductions across all episodes can be accounted for by a linear regression, including only three basic properties related to the meteorological conditions: mean daytime temperature, humidity, and ventilation to the greater Guangzhou urban area. While these results highlight the potential for cool roofs to mitigate peak temperatures during heat waves, the temperature reductions reported here are based on the upper bound case, which increases albedos of all roofs (but does not modify road albedo or wall albedo). PMID:26523605

  4. Heat tolerance of higher plants cenosis to damaging air temperatures

    NASA Astrophysics Data System (ADS)

    Ushakova, Sofya; Shklavtsova, Ekaterina

    Designing sustained biological-technical life support systems (BTLSS) including higher plants as a part of a photosynthesizing unit, it is important to foresee the multi species cenosis reaction on either stress-factors. Air temperature changing in BTLSS (because of failure of a thermoregulation system) up to the values leading to irreversible damages of photosynthetic processes is one of those factors. However, it is possible to increase, within the certain limits, the plant cenosis tolerance to the unfavorable temperatures’ effect due to the choice of the higher plants possessing resistance both to elevated and to lowered air temperatures. Besides, the plants heat tolerance can be increased when subjecting them during their growing to the hardening off temperatures’ effect. Thus, we have come to the conclusion that it is possible to increase heat tolerance of multi species cenosis under the damaging effect of air temperature of 45 (°) СC.

  5. Innovative coal gasification system with high temperature air

    SciTech Connect

    Yoshikawa, K.; Katsushima, H.; Kasahara, M.; Hasegawa, T.; Tanaka, R.; Ootsuka, T.

    1997-12-31

    This paper proposes innovative coal gasification power generation systems where coal is gasified with high temperature air of about 1300K produced by gasified coal fuel gas. The main features of these systems are high thermal efficiency, low NO{sub x} emission, compact desulfurization and dust removal equipment and high efficiency molten slag removal with a very compact gasifier. Recent experimental results on the pebble bed coal gasifier appropriate for high temperature air coal gasification are reported, where 97.7% of coal ash is successfully caught in the pebble bed and extracted without clogging. A new concept of high temperature air preheating system is proposed which is characterized by its high reliability and low cost.

  6. Urban air quality simulation with community multi-scale air quality (CMAQ) modeling system

    SciTech Connect

    Byun, D.; Young, J.; Gipson, G.; Schere, K.; Godowitch, J.

    1998-11-01

    In an effort to provide a state-of-the-science air quality modeling capability, US EPA has developed a new comprehensive and flexible Models-3 Community Multi-scale Air Quality (CMAQ) modeling system. The authors demonstrate CMAQ simulations for a high ozone episode in the northeastern US during 12-15 July 1995 and discuss meteorological issues important for modeling of urban air quality.

  7. Passive radiative cooling below ambient air temperature under direct sunlight.

    PubMed

    Raman, Aaswath P; Anoma, Marc Abou; Zhu, Linxiao; Rephaeli, Eden; Fan, Shanhui

    2014-11-27

    Cooling is a significant end-use of energy globally and a major driver of peak electricity demand. Air conditioning, for example, accounts for nearly fifteen per cent of the primary energy used by buildings in the United States. A passive cooling strategy that cools without any electricity input could therefore have a significant impact on global energy consumption. To achieve cooling one needs to be able to reach and maintain a temperature below that of the ambient air. At night, passive cooling below ambient air temperature has been demonstrated using a technique known as radiative cooling, in which a device exposed to the sky is used to radiate heat to outer space through a transparency window in the atmosphere between 8 and 13 micrometres. Peak cooling demand, however, occurs during the daytime. Daytime radiative cooling to a temperature below ambient of a surface under direct sunlight has not been achieved because sky access during the day results in heating of the radiative cooler by the Sun. Here, we experimentally demonstrate radiative cooling to nearly 5 degrees Celsius below the ambient air temperature under direct sunlight. Using a thermal photonic approach, we introduce an integrated photonic solar reflector and thermal emitter consisting of seven layers of HfO2 and SiO2 that reflects 97 per cent of incident sunlight while emitting strongly and selectively in the atmospheric transparency window. When exposed to direct sunlight exceeding 850 watts per square metre on a rooftop, the photonic radiative cooler cools to 4.9 degrees Celsius below ambient air temperature, and has a cooling power of 40.1 watts per square metre at ambient air temperature. These results demonstrate that a tailored, photonic approach can fundamentally enable new technological possibilities for energy efficiency. Further, the cold darkness of the Universe can be used as a renewable thermodynamic resource, even during the hottest hours of the day. PMID:25428501

  8. Performance of High Temperature Air Combustion Boiler with Low NOx Emission

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hiromichi; Ito, Yoshihito; Tsuruta, Naoki; Yoshikawa, Kunio

    Thermal performance in the experiments and three-dimensional numerical simulations for a high temperature air combustion boiler where fuel can be efficiently combusted by high temperature preheated air (800°C-1000°C) is examined. The boiler can burn not only natural gas but also low calorific gas (e. g. full gasification gas obtained from coal or wastes). In the boiler, four regenerative burners are installed. This boiler has new features that not only air but also gasification gas is heated up to 900°C, and combination of burners is switched every 15 seconds where two burners are used as inlets of fuel and air and the other two burners are used as outlets of exhaust gas. Natural gas and syngas obtained from coal are burned. The NOx emission for each fuel is less than 50ppm. The heat transfer of three-dimensional calculation is predicted higher than that of experiment.

  9. Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software

    NASA Technical Reports Server (NTRS)

    Hunter, George; Boisvert, Benjamin

    2013-01-01

    This document is the final report for the project entitled "Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software." This report consists of 17 sections which document the results of the several subtasks of this effort. The Probabilistic NAS Platform (PNP) is an air operations simulation platform developed and maintained by the Saab Sensis Corporation. The improvements made to the PNP simulation include the following: an airborne distributed separation assurance capability, a required time of arrival assignment and conformance capability, and a tactical and strategic weather avoidance capability.

  10. Emission Controls Using Different Temperatures of Combustion Air

    PubMed Central

    Holubčík, Michal; Papučík, Štefan

    2014-01-01

    The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass. PMID:24971376

  11. Spatial Disaggregation of the 0.25-degree GLDAS Air Temperature Dataset to 30-arcsec Resolution

    NASA Astrophysics Data System (ADS)

    Ji, L.; Senay, G. B.; Verdin, J. P.; Velpuri, N. M.

    2015-12-01

    Air temperature is a key input variable in ecological and hydrological models for simulating the hydrological cycle and water budget. Several global reanalysis products have been developed at different organizations, which provide gridded air temperature datasets at resolutions ranging from 0.25º to 2.5º (or 27.8 - 278.3 km at the equator). However, gridded air temperature products at a high-resolution (≤1 km) are available only for limited areas of the world. To meet the needs for global eco-hydrological modeling, we aim to produce a continuous daily air temperature datasets at 1-km resolution for the global coverage. In this study, we developed a technique that spatially disaggregates the 0.25º Global Land Data Assimilation System (GLDAS) daily air temperature data to 30-arcsec (0.928 km at the equator) resolution by integrating the GLDAS data with the 30-arcsec WorldClim 1950 - 2000 monthly normal air temperature data. The method was tested using the GLDAS and Worldclim maximum and minimum air temperature datasets from 2002 and 2010 for the conterminous Unites States and Africa. The 30-arcsec disaggregated GLDAS (GLDASd) air temperature dataset retains the mean values of the original GLDAS data, while adding spatial variabilities inherited from the Worldclim data. A great improvement in GLDAS disaggregation is shown in mountain areas where complex terrain features have strong impact on temperature. We validated the disaggregation method by comparing the GLDASd product with daily meteorological observations archived by the Global Historical Climatology Network (GHCN) and the Global Surface Summary of the Day (GSOD) datasets. Additionally, the 30-arcsec TopoWX daily air temperature product was used to compare with the GLDASd data for the conterminous United States. The proposed data disaggregation method provides a convenient and efficient tool for generating a global high-resolution air temperature dataset, which will be beneficial to global eco

  12. The use of speech technology in air traffic control simulators

    NASA Astrophysics Data System (ADS)

    Harrison, J. A.; Hobbs, G. R.; Howes, J. R.; Cope, N.

    The advantages of applying speech technology to air traffic control (ATC) simulators are discussed with emphasis placed on the simulation of the pilot end of the pilot-controller dialog. Speech I/O in an ATC simulator is described as well as technology capability, and research on an electronic blip driver. It is found that the system is easier to use and performs better for less experienced controllers.

  13. Variability of Winter Air Temperature in Mid-Latitude Europe

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

    2002-01-01

    The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud

  14. Pulsed positive streamer discharges in air at high temperatures

    NASA Astrophysics Data System (ADS)

    Ono, Ryo; Kamakura, Taku

    2016-08-01

    Atmospheric-pressure air pulsed positive streamer discharges are generated in a 13 mm point-plane gap in the temperature range of 293 K–1136 K, and the effect of temperature on the streamer discharges is studied. When the temperature is increased, the product of applied voltage and temperature VT proportional to the reduced electric field can be used as a primary parameter that determines some discharge parameters regardless of temperature. For a given VT, the transferred charge per pulse, streamer diameter, product of discharge energy and temperature, and length of secondary streamer are almost constant regardless of T, whereas the streamer velocity decreases with increasing T and the decay rate of the discharge current is proportional to 1/T. The N2(C) emission intensity is approximately determined by the discharge energy independent of T. These results are useful to predict the streamer discharge and its reactive species production when the ambient temperature is increased.

  15. Effects of air flow directions on composting process temperature profile

    SciTech Connect

    Kulcu, Recep; Yaldiz, Osman

    2008-07-01

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO{sub 2} and O{sub 2} ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.

  16. Temperature gradients and clear-air turbulence probabilities

    NASA Technical Reports Server (NTRS)

    Bender, M. A.; Panofsky, H. A.; Peslen, C. A.

    1976-01-01

    In order to forecast clear-air turbulence (CAT) in jet aircraft flights, a study was conducted in which the data from a special-purpose instrument aboard a Boeing 747 jet airliner were compared with satellite-derived radiance gradients, conventional temperature gradients from analyzed maps, and temperature gradients obtained from a total air temperature sensor on the plane. The advantage of making use of satellite-derived data is that they are available worldwide without the need for radiosonde observations, which are scarce in many parts of the world. Major conclusions are that CAT probabilities are significantly higher over mountains than flat terrain, and that satellite radiance gradients appear to discriminate between CAT and no CAT better than conventional temperature gradients over flat lands, whereas the reverse is true over mountains, the differences between the two techniques being not large over mountains.

  17. The Effects of Air Pollution and Temperature on COPD.

    PubMed

    Hansel, Nadia N; McCormack, Meredith C; Kim, Victor

    2016-06-01

    Chronic Obstructive Pulmonary Disease (COPD) affects 12-16 million people in the United States and is the third-leading cause of death. In developed countries, smoking is the greatest risk factor for the development of COPD, but other exposures also contribute to the development and progression of the disease. Several studies suggest, though are not definitive, that outdoor air pollution exposure is linked to the prevalence and incidence of COPD. Among individuals with COPD, outdoor air pollutants are associated with loss of lung function and increased respiratory symptoms. In addition, outdoor air pollutants are also associated with COPD exacerbations and mortality. There is much less evidence for the impact of indoor air on COPD, especially in developed countries in residences without biomass exposure. The limited existing data suggests that indoor particulate matter and nitrogen dioxide concentrations are linked to increased respiratory symptoms among patients with COPD. In addition, with the projected increases in temperature and extreme weather events in the context of climate change there has been increased attention to the effects of heat exposure. Extremes of temperature-both heat and cold-have been associated with increased respiratory morbidity in COPD. Some studies also suggest that temperature may modify the effect of pollution exposure and though results are not conclusive, understanding factors that may modify susceptibility to air pollution in patients with COPD is of utmost importance. PMID:26683097

  18. Experimental and theoretical analysis results for high temperature air combustion

    SciTech Connect

    Tanigawa, Tadashi; Morita, Mitsunobu

    1998-07-01

    With Japan's preparation of its Action program to prevent global warming in 1990 and the holding of the United National Conference on Environment and Development (the Earth Summit) in 1992 as a backdrop, reflecting the global effort to protect the environment, a high performance industrial furnace development project was launched in 1993 by the New Energy and Industrial Technology Development Organization (NEDO). This project focuses on the development of a combustion technology which uses air that is preheated to extremely high temperatures (above 1,000 C), heretofore considered impossible. Not only can this technology reduce carbon dioxide emission, thought to cause the greenhouse effect, by over 30%, but it can also reduce nitrogen oxide emission by nearly half. This new technology makes use of the recently-developed high-cycle regenerative heat exchanger, for preheating the furnace air supply. This exchanger preheats air to above 1,000 C, much higher than for conventional furnaces, and then this air is injected with fuel. R and D data have shown that CO{sub 2} and NO{sub x} emissions can be reduced markedly. However, the theoretical analysis is yet to be made, thereby hampering efforts to have this advanced technology become widely adopted. This project accumulated new data related to uniform temperature distribution, high energy heat transfer and low NO{sub x} as common characteristics of high temperature air combustion.

  19. Flame Speeds of Methane-Air, Propane-Air, and Ethylene-Air Mixtures at Low Initial Temperatures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L; Heimel, Sheldon

    1952-01-01

    Flame speeds were determined for methane-air, propane-air, and ethylene-air mixtures at -73 C and for methane-air mixtures at -132 C. The data extend the curves of maximum flame speed against initial mixture temperature previously established for the range from room temperature to 344 C. Empirical equations for maximum flame speed u(cm/ sec) as a function of initial mixture temperature T(sub O) were determined to be as follows: for methane, for T(sub O) from 141 to 615 K, u = 8 + 0.000160 T(sub O)(exp 2.11); for propane, for T(sub O) from 200 to 616 K, u = 10 + 0.000342 T(sub O)(exp 2.00); for ethylene, for T(sub O) from 200 to 617 K, u = 10 + 0.00259 T(sub O)(exp 1.74). Relative flame speeds at low initial temperatures were predicted within approximately 20 percent by either the thermal theory as presented by Semenov or by the diffusion theory of Tanford and Pease. The same order was found previously for high initial temperatures. The low-temperature data were also found to extend the linear correlations between maximum flame speed and calculated equilibrium active-radical concentrations, which were established by the previously reported high-temperature data.

  20. Geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppälä, A.; Randall, C. E.; Clilverd, M. A.; Rozanov, E.; Rodger, C. J.

    2009-10-01

    Here we use the ERA-40 and ECMWF operational surface level air temperature data sets from 1957 to 2006 to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the A p index. Previous modeling work has suggested that NO x produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in surface air temperatures (SATs). We find that during winter months, polar SATs in years with high A p index are different than in years with low A p index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, depending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings (SSWs) are excluded. We take into account solar irradiance variations, unlike previous analyses of geomagnetic effects in ERA-40 and operational data. Although we cannot conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating wintertime surface air temperatures. We tested our SAT results against variation in the Quasi Biennial Oscillation, the El Niño Southern Oscillation and the Southern Annular Mode. The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode, and we cannot robustly exclude a chance linkage between sea surface temperature variability and geomagnetic activity.

  1. Drier Air, Lower Temperatures, and Triggering of Paroxysmal Atrial Fibrillation

    PubMed Central

    Nguyen, Jennifer L.; Link, Mark S.; Luttmann-Gibson, Heike; Laden, Francine; Schwartz, Joel; Wessler, Benjamin S.; Mittleman, Murray A.; Gold, Diane R.; Dockery, Douglas W.

    2015-01-01

    Background The few previous studies on the onset of paroxysmal atrial fibrillation and meteorologic conditions have focused on outdoor temperature and hospital admissions, but hospital admissions are a crude indicator of atrial fibrillation incidence, and studies have found other weather measures in addition to temperature to be associated with cardiovascular outcomes. Methods Two hundred patients with dual chamber implantable cardioverter-defibrillators were enrolled and followed prospectively from 2006 to 2010 for new onset episodes of atrial fibrillation. The date and time of arrhythmia episodes documented by the implanted cardioverter-defibrillators were linked to meteorologic data and examined using a case-crossover analysis. We evaluated associations with outdoor temperature, apparent temperature, air pressure, and three measures of humidity (relative humidity, dew point, and absolute humidity). Results Of the 200 enrolled patients, 49 patients experienced 328 atrial fibrillation episodes lasting ≥30 seconds. Lower temperatures in the prior 48 hours were positively associated with atrial fibrillation. Lower absolute humidity (ie, drier air) had the strongest and most consistent association: each 0.5 g/m3 decrease in the prior 24 hours increased the odds of atrial fibrillation by 4% (95% confidence interval [CI]: 0%, 7%) and by 5% (95% CI: 2%, 8%) for exposure in the prior 2 hours. Results were similar for dew point but slightly weaker. Conclusions Recent exposure to drier air and lower temperatures were associated with the onset of atrial fibrillation among patients with known cardiac disease, supporting the hypothesis that meteorologic conditions trigger acute cardiovascular episodes. PMID:25756220

  2. Modeling daily average stream temperature from air temperature and watershed area

    NASA Astrophysics Data System (ADS)

    Butler, N. L.; Hunt, J. R.

    2012-12-01

    Habitat restoration efforts within watersheds require spatial and temporal estimates of water temperature for aquatic species especially species that migrate within watersheds at different life stages. Monitoring programs are not able to fully sample all aquatic environments within watersheds under the extreme conditions that determine long-term habitat viability. Under these circumstances a combination of selective monitoring and modeling are required for predicting future geospatial and temporal conditions. This study describes a model that is broadly applicable to different watersheds while using readily available regional air temperature data. Daily water temperature data from thirty-eight gauges with drainage areas from 2 km2 to 2000 km2 in the Sonoma Valley, Napa Valley, and Russian River Valley in California were used to develop, calibrate, and test a stream temperature model. Air temperature data from seven NOAA gauges provided the daily maximum and minimum air temperatures. The model was developed and calibrated using five years of data from the Sonoma Valley at ten water temperature gauges and a NOAA air temperature gauge. The daily average stream temperatures within this watershed were bounded by the preceding maximum and minimum air temperatures with smaller upstream watersheds being more dependent on the minimum air temperature than maximum air temperature. The model assumed a linear dependence on maximum and minimum air temperature with a weighting factor dependent on upstream area determined by error minimization using observed data. Fitted minimum air temperature weighting factors were consistent over all five years of data for each gauge, and they ranged from 0.75 for upstream drainage areas less than 2 km2 to 0.45 for upstream drainage areas greater than 100 km2. For the calibration data sets within the Sonoma Valley, the average error between the model estimated daily water temperature and the observed water temperature data ranged from 0.7

  3. Evaluation of the Global Land Data Assimilation System (GLDAS) air temperature data products

    NASA Astrophysics Data System (ADS)

    Ji, L.; Senay, G. B.; Verdin, J. P.

    2014-12-01

    There is a high demand for agro-hydrologic models to use gridded surface air temperature data as the model input for estimating regional and global water budget and cycle. The Global Land Data Assimilation System (GLDAS) developed by combining simulation models with observations provides a long-term gridded meteorological dataset at the global coverage. However, the GLDAS air temperature products have not been comprehensively evaluated, although the accuracy of the products was assessed in limited areas. In this study, we compared the daily 0.25° resolution GLDAS air temperature data with two reference datasets: (1) 1-km resolution gridded Daymet data (2002 and 2010) for the Conterminous United States, and (2) global meteorological observations (2000 - 2011) archived from the Global Historical Climatology Network (GHCN). The comparison of the GLDAS datasets with the GHCN datasets including 13,511 weather stations indicates a fairly high accuracy of the GLDAS data for daily maximum temperature [bias is 1.2 C°, root mean square error (RMSE) is 3.9 C°, and R2 is 0.92] and daily minimum temperature (bias is -1.4 C°, RMSE is 5.4 C°, and R2 is 0.82). The quality of the GLDAS air temperature data, however, is not always consistent in different regions of the world; for example, some areas in Africa and South America show relatively low accurate estimates. Spatial and temporal analyses reveal a high agreement between GLDAS and Daymet daily air temperature datasets, although spatial details in high mountainous areas are not sufficiently estimated by the GLDAS data. Our evaluation of the GLDAS data demonstrates that the air temperature estimates are generally accurate, but cautions should be taken when the data are used in mountainous areas or places with sparse weather stations.

  4. Simulation studies of air transport operational problems

    NASA Technical Reports Server (NTRS)

    Lauber, J. K.; Billings, C. E.; Stevenson, J. E.; Ruffell-Smith, H. P.; Cooper, G. E.

    1976-01-01

    An experimental evaluation of the monitored approach procedure for conducting low visibility instrument approaches is described. Four airline crews each flew 16 approaches using the monitored procedure and 16 using a modified standard procedure in a DC-10 simulator under various conditions of visibility, wind shear and turbulence, and radar vectoring scenarios. In terms of system measures of aircrew performance, no major differences were found. Pilot opinion data indicate that there are some desirable characteristics of the monitored procedure, particularly with reference to the increased role of the flight engineer in conducting low visibility approaches. Rationale for developing approach procedures is discussed.

  5. Advances in Fast Response Acoustically Derived Air Temperature Measurements

    NASA Astrophysics Data System (ADS)

    Bogoev, Ivan; Jacobsen, Larry; Horst, Thomas; Conrad, Benjamin

    2016-04-01

    Fast-response accurate air-temperature measurements are required when estimating turbulent fluxes of heat, water and carbon dioxide by open-path eddy-covariance technique. In comparison with contact thermometers like thermocouples, ultra-sonic thermometers do not suffer from solar radiation loading, water vapor condensation and evaporative cooling effects. Consequently they have the potential to provide more accurate true air temperature measurements. The absolute accuracy of the ultrasonic thermometer is limited by the following parameters: the distance between the transducer pairs, transducer delays associated with the electrical-acoustic signal conversion that vary with temperature, components of the wind vector that are normal to the ultrasonic paths, and humidity. The distance between the transducer pairs is commonly obtained by coordinate measuring machine. Improved accuracy demonstrated in this study results from increased stiffness in the anemometer head to better maintain the ultrasonic path-length distances. To further improve accuracy and account for changes in transducer delays and distance as a function of temperature, these parameters are characterized in a zero-wind chamber over the entire operating temperature range. When the sonic anemometer is combined with a co-located fast-response water vapor analyzer, like in the IRGASON instrument, speed of sound can be compensated for humidity effects on a point-by-point basis resulting in a true fast-response air temperature measurement. Laboratory test results show that when the above steps are implemented in the calibration of the ultrasonic thermometer air-temperature accuracy better than ±0.5 degrees Celsius can be achieved over the entire operating range. The approach is also validated in a field inter-comparison with an aspirated thermistor probe mounted in a radiation shield.

  6. Real-time simulation of helicopter air-to-air combat

    NASA Technical Reports Server (NTRS)

    Austin, Fred; George, Dino; Bivens, Court

    1991-01-01

    The AUTOMAN computer program develops automated maneuvering decisions for helicopters during air-to-air combat over hilly terrain. Recently, the capabilities of this program have been extended and enhanced significantly. The revised program was installed at the NASA Ames manned flight-simulation facility to drive a computer-generated image of an enemy helicopter, thereby providing an adversary for the human pilot. Maneuvers are selected by employing game theory. Enhancements include a guidance law for target acquisition when a firing opportunity arises; fire-control sequence logic; improved low-flying capabilities; line-of-sight computations for the cockpit field-of-view, terrain obstructions, and visual range limits; use of terrain for masking; air-to-air collision-avoidance maneuvers; decision on dispensing flares and chaff; and adjustable levels of pilot experience. The program was found to be extremely useful for both rotorcraft handling-quality evaluations and air-to-air combat training.

  7. Air moisture control on ocean surface temperature, hidden key to the warm bias enigma

    NASA Astrophysics Data System (ADS)

    Hourdin, Frédéric; Gǎinusǎ-Bogdan, Alina; Braconnot, Pascale; Dufresne, Jean-Louis; Traore, Aboul-Khadre; Rio, Catherine

    2015-12-01

    The systematic overestimation by climate models of the surface temperature over the eastern tropical oceans is generally attributed to an insufficient oceanic cooling or to an underestimation of stratocumulus clouds. We show that surface evaporation contributes as much as clouds to the dispersion of the warm bias intensity in a multimodel simulations ensemble. The models with the largest warm biases are those with the highest surface heating by radiation and lowest evaporative cooling in atmospheric simulations with prescribed sea surface temperatures. Surface evaporation also controls the amplitude of the surface temperature response to this overestimated heating, when the atmosphere is coupled to an ocean. Evaporation increases with temperature both because of increasing saturation humidity and of an unexpected drying of the near-surface air. Both the origin of the bias and this temperature adjustment point to the key role of near-surface relative humidity and its control by the atmospheric model.

  8. The mathematical simulation of the temperature fields of building envelopes under permanent frozen soil conditions

    NASA Astrophysics Data System (ADS)

    Anisimov, M. V.; Babuta, M. N.; Kuznetsova, U. N.; Safonova, E. V.; Minaeva, O. M.

    2016-04-01

    The physical-mathematical model of the thermal state of the aired technical underground taking into account the air exchange and design features of construction under permanent frozen soil conditions has been suggested. The computational scheme of the temperature fields prediction of building envelopes of projected buildings and soil under and nearby buildings has been developed. The numerical simulation of the temperature fields of building envelopes changes was conducted during a year. The results of the numerical simulation showed that the heat coming from the technical undergrounds and through the walls does not influence the temperature field of the soil neither under a building nor at a distance from it.

  9. An Analytical Solution for Mechanical Responses Induced by Temperature and Air Pressure in a Lined Rock Cavern for Underground Compressed Air Energy Storage

    NASA Astrophysics Data System (ADS)

    Zhou, Shu-Wei; Xia, Cai-Chu; Du, Shi-Gui; Zhang, Ping-Yang; Zhou, Yu

    2015-03-01

    Mechanical responses induced by temperature and air pressure significantly affect the stability and durability of underground compressed air energy storage (CAES) in a lined rock cavern. An analytical solution for evaluating such responses is, thus, proposed in this paper. The lined cavern of interest consists of three layers, namely, a sealing layer, a concrete lining and the host rock. Governing equations for cavern temperature and air pressure, which involve heat transfer between the air and surrounding layers, are established first. Then, Laplace transform and superposition principle are applied to obtain the temperature around the lined cavern and the air pressure during the operational period. Afterwards, a thermo-elastic axisymmetrical model is used to analytically determine the stress and displacement variations induced by temperature and air pressure. The developments of temperature, displacement and stress during a typical operational cycle are discussed on the basis of the proposed approach. The approach is subsequently verified with a coupled compressed air and thermo-mechanical numerical simulation and by a previous study on temperature. Finally, the influence of temperature on total stress and displacement and the impact of the heat transfer coefficient are discussed. This paper shows that the temperature sharply fluctuates only on the sealing layer and the concrete lining. The resulting tensile hoop stresses on the sealing layer and concrete lining are considerably large in comparison with the initial air pressure. Moreover, temperature has a non-negligible effect on the lined cavern for underground compressed air storage. Meanwhile, temperature has a greater effect on hoop and longitudinal stress than on radial stress and displacement. In addition, the heat transfer coefficient affects the cavern stress to a higher degree than the displacement.

  10. The mass and speed dependence of meteor air plasma temperatures

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Laux, Christophe O.; Wilson, Michael A.; Schaller, Emily L.

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  11. CARS Temperature and Species Measurements For Air Vehicle Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Gord, James R.; Grisch, Frederic; Klimenko, Dmitry; Clauss, Walter

    2005-01-01

    The coherent anti-Stokes Raman spectroscopy (CARS) method has recently been used in the United States and Europe to probe several different types of propulsion systems for air vehicles. At NASA Langley Research Center in the United States, CARS has been used to simultaneously measure temperature and the mole fractions of N2, O2 and H2 in a supersonic combustor, representative of a scramjet engine. At Wright- Patterson Air Force Base in the United States, CARS has been used to simultaneously measure temperature and mole fractions of N2, O2 and CO2, in the exhaust stream of a liquid-fueled, gas-turbine combustor. At ONERA in France and the DLR in Germany researchers have used CARS to measure temperature and species concentrations in cryogenic LOX-H2 rocket combustion chambers. The primary aim of these measurements has been to provide detailed flowfield information for computational fluid dynamics (CFD) code validation.

  12. Microwave temperature profiler for clear air turbulence prediction

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    1992-01-01

    A method is disclosed for determining Richardson Number, Ri, or its reciprocal, RRi, for clear air prediction using measured potential temperature and determining the vertical gradient of potential temperature, d(theta)/dz. Wind vector from the aircraft instrumentation versus potential temperature, dW/D(theta), is determined and multiplies by d(theta)/dz to obtain dW/dz. Richardson number or its reciprocal is then determined from the relationship Ri = K(d theta)/dz divided by (dW/dz squared) for use in detecting a trend toward a threshold value for the purpose of predicting clear air turbulence. Other equations for this basic relationship are disclosed together with the combination of other atmospheric observables using multiple regression techniques.

  13. Symmetric scaling properties in global surface air temperature anomalies

    NASA Astrophysics Data System (ADS)

    Varotsos, Costas A.; Efstathiou, Maria N.

    2015-08-01

    We have recently suggested "long-term memory" or internal long-range correlation within the time-series of land-surface air temperature (LSAT) anomalies in both hemispheres. For example, an increasing trend in the LSAT anomalies is followed by another one at a different time in a power-law fashion. However, our previous research was mainly focused on the overall long-term persistence, while in the present study, the upward and downward scaling dynamics of the LSAT anomalies are analysed, separately. Our results show that no significant fluctuation differences were found between the increments and decrements in LSAT anomalies, over the whole Earth and over each hemisphere, individually. On the contrary, the combination of land-surface air and sea-surface water temperature anomalies seemed to cause a departure from symmetry and the increments in the land and sea surface temperature anomalies appear to be more persistent than the decrements.

  14. Fiber optic distributed temperature sensing for the determination of air temperature

    NASA Astrophysics Data System (ADS)

    de Jong, S. A. P.; Slingerland, J. D.; van de Giesen, N. C.

    2015-01-01

    This paper describes a method to correct for the effect of solar radiation in atmospheric distributed temperature sensing (DTS) applications. By using two cables with different diameters, one can determine what temperature a zero diameter cable would have. Such a virtual cable would not be affected by solar heating and would take on the temperature of the surrounding air. With two unshielded cable pairs, one black pair and one white pair, good results were obtained given the general consensus that shielding is needed to avoid radiation errors (WMO, 2010). The correlations between standard air temperature measurements and air temperatures derived from both cables of colors had a high correlation coefficient (r2=0.99) and a RMSE of 0.38 °C, compared to a RMSE of 2.40 °C for a 3.0 mm uncorrected black cable. A thin white cable measured temperatures that were close to air temperature measured with a nearby shielded thermometer (RMSE of 0.61 °C). The temperatures were measured along horizontal cables with an eye to temperature measurements in urban areas, but the same method can be applied to any atmospheric DTS measurements, and for profile measurements along towers or with balloons and quadcopters.

  15. The Effects of Air Pollution and Temperature on COPD

    PubMed Central

    Hansel, Nadia N.; McCormack, Meredith C.; Kim, Victor

    2016-01-01

    Chronic Obstructive Pulmonary Disease (COPD) affects 12–16 million people in the United States and is the third-leading cause of death. In developed countries, smoking is the greatest risk factor for the development of COPD, but other exposures also contribute to the development and progression of the disease. Several studies suggest, though are not definitive, that outdoor air pollution exposure is linked to the prevalence and incidence of COPD. Among individuals with COPD, outdoor air pollutants are associated with loss of lung function and increased respiratory symptoms. In addition, outdoor air pollutants are also associated with COPD exacerbations and mortality. There is much less evidence for the impact of indoor air on COPD, especially in developed countries in residences without biomass exposure. The limited existing data suggests that indoor particulate matter and nitrogen dioxide concentrations are linked to increased respiratory symptoms among patients with COPD. In addition, with the projected increases in temperature and extreme weather events in the context of climate change there has been increased attention to the effects of heat exposure. Extremes of temperature—both heat and cold—have been associated with increased respiratory morbidity in COPD. Some studies also suggest that temperature may modify the effect of pollution exposure and though results are not conclusive, understanding factors that may modify susceptibility to air pollution in patients with COPD is of utmost importance. PMID:26683097

  16. Spatial interpolation of monthly mean air temperature data for Latvia

    NASA Astrophysics Data System (ADS)

    Aniskevich, Svetlana

    2016-04-01

    Temperature data with high spatial resolution are essential for appropriate and qualitative local characteristics analysis. Nowadays the surface observation station network in Latvia consists of 22 stations recording daily air temperature, thus in order to analyze very specific and local features in the spatial distribution of temperature values in the whole Latvia, a high quality spatial interpolation method is required. Until now inverse distance weighted interpolation was used for the interpolation of air temperature data at the meteorological and climatological service of the Latvian Environment, Geology and Meteorology Centre, and no additional topographical information was taken into account. This method made it almost impossible to reasonably assess the actual temperature gradient and distribution between the observation points. During this project a new interpolation method was applied and tested, considering auxiliary explanatory parameters. In order to spatially interpolate monthly mean temperature values, kriging with external drift was used over a grid of 1 km resolution, which contains parameters such as 5 km mean elevation, continentality, distance from the Gulf of Riga and the Baltic Sea, biggest lakes and rivers, population density. As the most appropriate of these parameters, based on a complex situation analysis, mean elevation and continentality was chosen. In order to validate interpolation results, several statistical indicators of the differences between predicted values and the values actually observed were used. Overall, the introduced model visually and statistically outperforms the previous interpolation method and provides a meteorologically reasonable result, taking into account factors that influence the spatial distribution of the monthly mean temperature.

  17. Air pollution, temperature and pediatric influenza in Brisbane, Australia.

    PubMed

    Xu, Zhiwei; Hu, Wenbiao; Williams, Gail; Clements, Archie C A; Kan, Haidong; Tong, Shilu

    2013-09-01

    Previous studies have demonstrated the importance of weather variables in influencing the incidence of influenza. However, the role of air pollution is often ignored in identifying the environmental drivers of influenza. This research aims to examine the impacts of air pollutants and temperature on the incidence of pediatric influenza in Brisbane, Australia. Lab-confirmed daily data on influenza counts among children aged 0-14years in Brisbane from 2001 January 1st to 2008 December 31st were retrieved from Queensland Health. Daily data on maximum and minimum temperatures for the same period were supplied by the Australian Bureau of Meteorology. Winter was chosen as the main study season due to it having the highest pediatric influenza incidence. Four Poisson log-linear regression models, with daily pediatric seasonal influenza counts as the outcome, were used to examine the impacts of air pollutants (i.e., ozone (O3), particulate matter≤10μm (PM10) and nitrogen dioxide (NO2)) and temperature (using a moving average of ten days for these variables) on pediatric influenza. The results show that mean temperature (Relative risk (RR): 0.86; 95% Confidence Interval (CI): 0.82-0.89) was negatively associated with pediatric seasonal influenza in Brisbane, and high concentrations of O3 (RR: 1.28; 95% CI: 1.25-1.31) and PM10 (RR: 1.11; 95% CI: 1.10-1.13) were associated with more pediatric influenza cases. There was a significant interaction effect (RR: 0.94; 95% CI: 0.93-0.95) between PM10 and mean temperature on pediatric influenza. Adding the interaction term between mean temperature and PM10 substantially improved the model fit. This study provides evidence that PM10 needs to be taken into account when evaluating the temperature-influenza relationship. O3 was also an important predictor, independent of temperature. PMID:23911338

  18. Thermodynamic and Transport Properties of Real Air Plasma in Wide Range of Temperature and Pressure

    NASA Astrophysics Data System (ADS)

    Wang, Chunlin; Wu, Yi; Chen, Zhexin; Yang, Fei; Feng, Ying; Rong, Mingzhe; Zhang, Hantian

    2016-07-01

    Air plasma has been widely applied in industrial manufacture. In this paper, both dry and humid air plasmas' thermodynamic and transport properties are calculated in temperature 300-100000 K and pressure 0.1-100 atm. To build a more precise model of real air plasma, over 70 species are considered for composition. Two different methods, the Gibbs free energy minimization method and the mass action law method, are used to determinate the composition of the air plasma in a different temperature range. For the transport coefficients, the simplified Chapman-Enskog method developed by Devoto has been applied using the most recent collision integrals. It is found that the presence of CO2 has almost no effect on the properties of air plasma. The influence of H2O can be ignored except in low pressure air plasma, in which the saturated vapor pressure is relatively high. The results will serve as credible inputs for computational simulation of air plasma. supported by the National Key Basic Research Program of China (973 Program)(No. 2015CB251002), National Natural Science Foundation of China (Nos. 51521065, 51577145), the Science and Technology Project Funds of the Grid State Corporation (SGTYHT/13-JS-177), the Fundamental Research Funds for the Central Universities, and State Grid Corporation Project (GY71-14-004)

  19. Requirements for high-temperature air-cooled central receivers

    SciTech Connect

    Wright, J.D.; Copeland, R.J.

    1983-12-01

    The design of solar thermal central receivers will be shaped by the end user's need for energy. This paper identifies the requirements for receivers supplying heat for industrial processes or electric power generation in the temperature range 540 to 1000/sup 0/C and evaluates the effects of the requirements on air-cooled central receivers. Potential IPH applications are identified as large baseload users that are located some distance from the receiver. In the electric power application, the receiver must supply heat to a pressurized gas power cycle. The difficulty in providing cost-effective thermal transport and thermal storage for air-cooled receivers is a critical problem.

  20. Geant4 Simulation of Air Showers using Thinning Method

    NASA Astrophysics Data System (ADS)

    Sabra, Mohammad S.; Watts, John W.; Christl, Mark J.

    2015-04-01

    Simulation of complete air showers induced by cosmic ray particles becomes prohibitive at extreme energies due to the large number of secondary particles. Computing time of such simulations roughly scales with the energy of the primary cosmic ray particle, and becomes excessively large. To mitigate the problem, only small fraction of particles can be tracked and, then, the whole shower is reconstructed based on this sample. This method is called Thinning. Using this method in Geant4, we have simulated proton and iron air showers at extreme energies (E >1016 eV). Secondary particle densities are calculated and compared with the standard simulation program in this field, CORSIKA. This work is supported by the NASA Postdoctoral Program administrated by Oak Ridge Associated Universities.

  1. Simulating Human Cognition in the Domain of Air Traffic Control

    NASA Technical Reports Server (NTRS)

    Freed, Michael; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1995-01-01

    Experiments intended to assess performance in human-machine interactions are often prohibitively expensive, unethical or otherwise impractical to run. Approximations of experimental results can be obtained, in principle, by simulating the behavior of subjects using computer models of human mental behavior. Computer simulation technology has been developed for this purpose. Our goal is to produce a cognitive model suitable to guide the simulation machinery and enable it to closely approximate a human subject's performance in experimental conditions. The described model is designed to simulate a variety of cognitive behaviors involved in routine air traffic control. As the model is elaborated, our ability to predict the effects of novel circumstances on controller error rates and other performance characteristics should increase. This will enable the system to project the impact of proposed changes to air traffic control procedures and equipment on controller performance.

  2. Can air temperature be used to project influences of climate change on stream temperature?

    USGS Publications Warehouse

    Arismendi, Ivan; Safeeq, Mohammad; Dunham, Jason B.; Johnson, Sherri L.

    2014-01-01

    Worldwide, lack of data on stream temperature has motivated the use of regression-based statistical models to predict stream temperatures based on more widely available data on air temperatures. Such models have been widely applied to project responses of stream temperatures under climate change, but the performance of these models has not been fully evaluated. To address this knowledge gap, we examined the performance of two widely used linear and nonlinear regression models that predict stream temperatures based on air temperatures. We evaluated model performance and temporal stability of model parameters in a suite of regulated and unregulated streams with 11–44 years of stream temperature data. Although such models may have validity when predicting stream temperatures within the span of time that corresponds to the data used to develop them, model predictions did not transfer well to other time periods. Validation of model predictions of most recent stream temperatures, based on air temperature–stream temperature relationships from previous time periods often showed poor performance when compared with observed stream temperatures. Overall, model predictions were less robust in regulated streams and they frequently failed in detecting the coldest and warmest temperatures within all sites. In many cases, the magnitude of errors in these predictions falls within a range that equals or exceeds the magnitude of future projections of climate-related changes in stream temperatures reported for the region we studied (between 0.5 and 3.0 °C by 2080). The limited ability of regression-based statistical models to accurately project stream temperatures over time likely stems from the fact that underlying processes at play, namely the heat budgets of air and water, are distinctive in each medium and vary among localities and through time.

  3. Can air temperatures be used to project influences of climate change on stream temperatures?

    NASA Astrophysics Data System (ADS)

    Arismendi, I.; Safeeq, M.; Dunham, J.; Johnson, S. L.

    2013-12-01

    The lack of available in situ stream temperature records at broad spatiotemporal scales have been recognized as a major limiting factor in the understanding of thermal behavior of stream and river systems. This has motivated the promotion of a wide variety of models that use surrogates for stream temperatures including a regression approach that uses air temperature as the predictor variable. We investigate the long-term performance of widely used linear and non-linear regression models between air and stream temperatures to project the latter in future climate scenarios. Specifically, we examine the temporal variability of the parameters that define each of these models in long-term stream and air temperature datasets representing relatively natural and highly human-influenced streams. We selected 25 sites with long-term records that monitored year-round daily measurements of stream temperature (daily mean) in the western United States (California, Oregon, Idaho, Washington, and Alaska). Surface air temperature data from each site was not available. Therefore, we calculated daily mean surface air temperature for each site in contiguous US from a 1/16-degree resolution gridded surface temperature data. Our findings highlight several limitations that are endemic to linear or nonlinear regressions that have been applied in many recent attempts to project future stream temperatures based on air temperature. Our results also show that applications over longer time periods, as well as extrapolation of model predictions to project future stream temperatures are unlikely to be reliable. Although we did not analyze a broad range of stream types at a continental or global extent, our analysis of stream temperatures within the set of streams considered herein was more than sufficient to illustrate a number of specific limitations associated with statistical projections of stream temperature based on air temperature. Radar plots of Nash-Sutcliffe efficiency (NSE) values for

  4. Simulating future water temperatures in the North Santiam River, Oregon

    NASA Astrophysics Data System (ADS)

    Buccola, Norman L.; Risley, John C.; Rounds, Stewart A.

    2016-04-01

    A previously calibrated two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) of Detroit Lake in western Oregon was used in conjunction with inflows derived from Precipitation-Runoff Modeling System (PRMS) hydrologic models to examine in-lake and downstream water temperature effects under future climate conditions. Current and hypothetical operations and structures at Detroit Dam were imposed on boundary conditions derived from downscaled General Circulation Models in base (1990-1999) and future (2059-2068) periods. Compared with the base period, future air temperatures were about 2 °C warmer year-round. Higher air temperature and lower precipitation under the future period resulted in a 23% reduction in mean annual PRMS-simulated discharge and a 1 °C increase in mean annual estimated stream temperatures flowing into the lake compared to the base period. Simulations incorporating current operational rules and minimum release rates at Detroit Dam to support downstream habitat, irrigation, and water supply during key times of year resulted in lower future lake levels. That scenario results in a lake level that is above the dam's spillway crest only about half as many days in the future compared to historical frequencies. Managing temperature downstream of Detroit Dam depends on the ability to blend warmer water from the lake's surface with cooler water from deep in the lake, and the spillway is an important release point near the lake's surface. Annual average in-lake and release temperatures from Detroit Lake warmed 1.1 °C and 1.5 °C from base to future periods under present-day dam operational rules and fill schedules. Simulated dam operations such as beginning refill of the lake 30 days earlier or reducing minimum release rates (to keep more water in the lake to retain the use of the spillway) mitigated future warming to 0.4 and 0.9 °C below existing operational scenarios during the critical autumn spawning period for endangered salmonids. A

  5. Simulation of the secondary air system of aero engines

    NASA Astrophysics Data System (ADS)

    Kutz, K. J.; Speer, T. M.

    1994-04-01

    This paper describes a computer program for the simulation of secondary air systems. Typical flow system elements are presented, such as restrictors, tappings, seals, vortices, and coverplates. Two-phase flow as occurring in bearing chamber vent systems is briefly discussed. An algorithm is described for the solution of the resulting nonlinear equations. The validity of the simulation over the engine operation envelope is demonstrated by a comparison with test results.

  6. Persistence analysis of daily mean air temperature variation in Georgia

    NASA Astrophysics Data System (ADS)

    Matcharashvili, Teimuraz; Chelidze, Tamaz; Zhukova, Natalia; Mepharidze, Ekaterine; Sborshchikov, Alexander

    2010-05-01

    Extrapolation of observed linear trends is common practice in climate change researches on different scales. In this respect it is important, that though global warming is well established, the question of persistence of trends on regional scales remain controversial. Indeed, climate change for specific region and time by definition includes more than the simple average of weather conditions. Either random events or long-term changes, or more often combinations of them, can bring about significant swings in a variety of climate indicators from one time period to the next. Therefore in order to achieve further understanding of dynamics of climate change the character of stable peculiarities of analyzed dynamics should be investigated. Analysis of the character of long range correlations in climatological time series or peculiarities of their inherent memory is motivated exactly by this goal. Such analysis carried out on a different scales may help to understand spatial and temporal features of regional climate change. In present work the problem of persistence of observed trends in air temperature time series in Georgia was investigated. Longest available mean daily temperature time series of Tbilisi (1890-2008) were analyzed. Time series on shorter time scales of five stations in the West and East Georgia also were considered as well as monthly mean temperature time series of five stations. Additionally, temporally and spatially averaged daily and monthly mean air temperature time series were analyzed. Extent of persistence in mentioned time series were evaluated using R/S analysis calculation. Detrended and Multifractal Detrended Fluctuation Analysis as well as multi scaling analysis based on CWT have been used. Our results indicate that variation of daily or monthly mean temperatures reveals clear antipersistence on whole available time scale. It seems that antipersistence on global scale is general characteristics of mean air temperature variation and is not

  7. Historical changes in air temperature are evident in temperature fluxes measured in the sub-soil.

    NASA Astrophysics Data System (ADS)

    Fraser, Fiona; McCormick, Benjamin; Hallett, Paul; Wookey, Philip; Hopkins, David

    2013-04-01

    Warming trends in soil temperature have implications for a plethora of soil processes, including exacerbated climate change through the net release of greenhouse gases. Whereas long-term datasets of air temperature changes are abundant, a search of scientific literature reveals a lack of information on soil temperature changes and their specific consequences. We analysed five long-term data series collected in the UK (Dundee and Armagh) and Canada (Charlottetown, Ottawa and Swift Current). They show that the temperatures of soils at 5 - 20 cm depth, and sub-soils at 30 - 150 cm depth, increased in line with air temperature changes over the period 1958 - 2003. Differences were found, however, between soil and air temperatures when data were sub-divided into seasons. In spring, soil temperature warming ranged from 0.19°C at 30 cm in Armagh to 4.30°C at 50 cm in Charlottetown. In summer, however, the difference was smaller and ranged from 0.21°C at 10 cm in Ottawa to 3.70°C at 50 cm in Charlottetown. Winter temperatures were warmer in soil and ranged from 0.45°C at 5 cm in Charlottetown to 3.76°C at 150 cm in Charlottetown. There were significant trends in changes to soil temperature over time, whereas air temperature trends tended only to be significant in winter (changes range from 1.27°C in Armagh to 3.35°C in Swift Current). Differences in the seasonal warming patterns between air and soil temperatures have potential implications for the parameterization of models of biogeochemical cycling.

  8. RELATIONSHIP BETWEEN WATER TEMPERATURES AND AIR TEMPERATURES FOR CENTRAL US STREAMS

    EPA Science Inventory

    An analysis of the relationship between air and stream water temperature records for 11 rivers located in the central United States was conducted. he reliability of commonly available water temperature records was shown to be of unequal quality. imple linear relationships between...

  9. Air Temperature Estimation over the Third Pole Using MODIS LST

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Zhang, F.; Ye, M.; Che, T.

    2015-12-01

    The Third Pole is centered on the Tibetan Plateau (TP), which is the highest large plateau around the world with extremely complex terrain and climate conditions, resulting in very scarce meteorological stations especially in the vast west region. For these unobserved areas, the remotely sensed land surface temperature (LST) can greatly contribute to air temperature estimation. In our research we utilized the MODIS LST production from both TERRA and AQUA to estimate daily mean air temperature over the TP using multiple statistical models. Other variables used in the models include longitudes, latitudes, Julian day, solar zenith, NDVI and elevation. To select a relatively optimal model, we chose six popular and representative statistical models as candidate models including the multiple linear regression (MLR), the partial least squares regression (PLS), back propagate neural network (BPNN), support vector regression (SVR), random forests (RF) and Cubist regression (CR). The performances of the six models were compared for each possible combination of LSTs at four satellite pass times and two quality situations. Eventually a ranking table consisting of optimal models for each LST combination and quality situation was built up based on the validation results. By this means, the final production is generated providing daily mean air temperature with the least cloud blockage and acceptable accuracy. The average RMSEs of cross validation are mostly around 2℃. Stratified validations were also performed to test the expansibility to unobserved and high-altitude areas of the final models selected.

  10. STUDY ON AIR INGRESS MITIGATION METHODS IN THE VERY HIGH TEMPERATURE GAS COOLED REACTOR (VHTR)

    SciTech Connect

    Chang H. Oh

    2011-03-01

    An air-ingress accident followed by a pipe break is considered as a critical event for a very high temperature gas-cooled reactor (VHTR). Following helium depressurization, it is anticipated that unless countermeasures are taken, air will enter the core through the break leading to oxidation of the in-core graphite structure. Thus, without mitigation features, this accident might lead to severe exothermic chemical reactions of graphite and oxygen. Under extreme circumstances, a loss of core structural integrity may occur along with excessive release of radiological inventory. Idaho National Laboratory under the auspices of the U.S. Department of Energy is performing research and development (R&D) that focuses on key phenomena important during challenging scenarios that may occur in the VHTR. Phenomena Identification and Ranking Table (PIRT) studies to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important (Oh et al. 2006, Schultz et al. 2006). Consequently, the development of advanced air ingress-related models and verification and validation (V&V) requirements are part of the experimental validation plan. This paper discusses about various air-ingress mitigation concepts applicable for the VHTRs. The study begins with identifying important factors (or phenomena) associated with the air-ingress accident by using a root-cause analysis. By preventing main causes of the important events identified in the root-cause diagram, the basic air-ingress mitigation ideas can be conceptually derived. The main concepts include (1) preventing structural degradation of graphite supporters; (2) preventing local stress concentration in the supporter; (3) preventing graphite oxidation; (4) preventing air ingress; (5) preventing density gradient driven flow; (4) preventing fluid density gradient; (5) preventing fluid temperature gradient; (6) preventing high temperature. Based on the basic concepts listed above, various air

  11. SIMULATING URBAN AIR TOXICS OVER CONTINENTAL AND URBAN SCALES

    EPA Science Inventory

    The US EPA is evaluating a version of the CMAQ model to support risk assessment for the exposure to Hazardous Air Pollutants (HAPs). The model uses a variant of the CB4 chemical mechanism to simulate ambient concentrations of twenty HAPs that exist primarily as gaseous compounds...

  12. A PHOTOCHEMICAL BOX MODEL FOR URBAN AIR QUALITY SIMULATION

    EPA Science Inventory

    A simple 'box-approach' to air quality simulation modeling has been developed in conjunction with a newly formulated photochemical kinetic mechanism to produce an easily applied Photochemical Box Model (PBM). This approach represents an urban area as a single cell 20 km in both l...

  13. EMISSIONS OF AIR TOXICS FROM A SIMULATED CHARCOAL KILN

    EPA Science Inventory

    The report gives results of experiments in a laboratory-scale charcoal kiln simulator to evaluate emissions of hazardous air pollutants from the production of charcoal in Missouri-type kilns. Fixed combustion gases were measured using continuous monitors. In Addition, other pollu...

  14. Air Cooling for High Temperature Power Electronics (Presentation)

    SciTech Connect

    Waye, S.; Musselman, M.; King, C.

    2014-09-01

    Current emphasis on developing high-temperature power electronics, including wide-bandgap materials such as silicon carbide and gallium nitride, increases the opportunity for a completely air-cooled inverter at higher powers. This removes the liquid cooling system for the inverter, saving weight and volume on the liquid-to-air heat exchanger, coolant lines, pumps, and coolant, replacing them with just a fan and air supply ducting. We investigate the potential for an air-cooled heat exchanger from a component and systems-level approach to meet specific power and power density targets. A proposed baseline air-cooled heat exchanger design that does not meet those targets was optimized using a parametric computational fluid dynamics analysis, examining the effects of heat exchanger geometry and device location, fixing the device heat dissipation and maximum junction temperature. The CFD results were extrapolated to a full inverter, including casing, capacitor, bus bar, gate driver, and control board component weights and volumes. Surrogate ducting was tested to understand the pressure drop and subsequent system parasitic load. Geometries that met targets with acceptable loads on the system were down-selected for experimentation. Nine baseline configuration modules dissipated the target heat dissipation, but fell below specific power and power density targets. Six optimized configuration modules dissipated the target heat load, exceeding the specific power and power density targets. By maintaining the same 175 degrees C maximum junction temperature, an optimized heat exchanger design and higher device heat fluxes allowed a reduction in the number of modules required, increasing specific power and power density while still maintaining the inverter power.

  15. Global surface air temperature variations: 1851-1984

    SciTech Connect

    Jones, P.D.; Raper, S.C.B.; Kelly, P.M.

    1986-11-01

    Many attempts have been made to combine station surface air temperature data into an average for the Northern Hemisphere. Fewer attempts have been made for the Southern Hemisphere because of the unavailability of data from the Antarctic mainland before the 1950s and the uncertainty of making a hemispheric estimate based solely on land-based analyses for a hemisphere that is 80% ocean. Past estimates have been based largely on data from the World Weather Records (Smithsonian Institution, 1927, 1935, 1947, and U.S. Weather Bureau, 1959-82) and have been made without considerable effort to detect and correct station inhomogeneities. Better estimates for the Southern Hemisphere are now possible because of the availability of 30 years of climatological data from Antarctica. The mean monthly surface air temperature anomalies presented in this package for the than those previously published because of the incorporation of data previously hidden away in archives and the analysis of station homogeneity before estimation.

  16. Stratospheric Temperature Changes: Observations and Model Simulations

    NASA Technical Reports Server (NTRS)

    Ramaswamy, V.; Chanin, M.-L.; Angell, J.; Barnett, J.; Gaffen, D.; Gelman, M.; Keckhut, P.; Koshelkov, Y.; Labitzke, K.; Lin, J.-J. R.

    1999-01-01

    This paper reviews observations of stratospheric temperatures that have been made over a period of several decades. Those observed temperatures have been used to assess variations and trends in stratospheric temperatures. A wide range of observation datasets have been used, comprising measurements by radiosonde (1940s to the present), satellite (1979 - present), lidar (1979 - present) and rocketsonde (periods varying with location, but most terminating by about the mid-1990s). In addition, trends have also been assessed from meteorological analyses, based on radiosonde and/or satellite data, and products based on assimilating observations into a general circulation model. Radiosonde and satellite data indicate a cooling trend of the annual-mean lower stratosphere since about 1980. Over the period 1979-1994, the trend is 0.6K/decade. For the period prior to 1980, the radiosonde data exhibit a substantially weaker long-term cooling trend. In the northern hemisphere, the cooling trend is about 0.75K/decade in the lower stratosphere, with a reduction in the cooling in mid-stratosphere (near 35 km), and increased cooling in the upper stratosphere (approximately 2 K per decade at 50 km). Model simulations indicate that the depletion of lower stratospheric ozone is the dominant factor in the observed lower stratospheric cooling. In the middle and upper stratosphere both the well-mixed greenhouse gases (such as CO) and ozone changes contribute in an important manner to the cooling.

  17. Simulation of atmospheric temperature effects on cosmic ray muon flux

    NASA Astrophysics Data System (ADS)

    Tognini, Stefano Castro; Gomes, Ricardo Avelino

    2015-05-01

    The collision between a cosmic ray and an atmosphere nucleus produces a set of secondary particles, which will decay or interact with other atmosphere elements. This set of events produced a primary particle is known as an extensive air shower (EAS) and is composed by a muonic, a hadronic and an electromagnetic component. The muonic flux, produced mainly by pions and kaons decays, has a dependency with the atmosphere's effective temperature: an increase in the effective temperature results in a lower density profile, which decreases the probability of pions and kaons to interact with the atmosphere and, consequently, resulting in a major number of meson decays. Such correlation between the muon flux and the atmosphere's effective temperature was measured by a set of experiments, such as AMANDA, Borexino, MACRO and MINOS. This phenomena can be investigated by simulating the final muon flux produced by two different parameterizations of the isothermal atmospheric model in CORSIKA, where each parameterization is described by a depth function which can be related to the muon flux in the same way that the muon flux is related to the temperature. This research checks the agreement among different high energy hadronic interactions models and the physical expected behavior of the atmosphere temperature effect by analyzing a set of variables, such as the height of the primary interaction and the difference in the muon flux.

  18. Simulation of atmospheric temperature effects on cosmic ray muon flux

    SciTech Connect

    Tognini, Stefano Castro; Gomes, Ricardo Avelino

    2015-05-15

    The collision between a cosmic ray and an atmosphere nucleus produces a set of secondary particles, which will decay or interact with other atmosphere elements. This set of events produced a primary particle is known as an extensive air shower (EAS) and is composed by a muonic, a hadronic and an electromagnetic component. The muonic flux, produced mainly by pions and kaons decays, has a dependency with the atmosphere’s effective temperature: an increase in the effective temperature results in a lower density profile, which decreases the probability of pions and kaons to interact with the atmosphere and, consequently, resulting in a major number of meson decays. Such correlation between the muon flux and the atmosphere’s effective temperature was measured by a set of experiments, such as AMANDA, Borexino, MACRO and MINOS. This phenomena can be investigated by simulating the final muon flux produced by two different parameterizations of the isothermal atmospheric model in CORSIKA, where each parameterization is described by a depth function which can be related to the muon flux in the same way that the muon flux is related to the temperature. This research checks the agreement among different high energy hadronic interactions models and the physical expected behavior of the atmosphere temperature effect by analyzing a set of variables, such as the height of the primary interaction and the difference in the muon flux.

  19. Industrial applications of MHD high temperature air heater technology

    NASA Astrophysics Data System (ADS)

    Saari, D. P.; Fenstermacher, J. E.; White, L. R.; Marksberry, C. L.

    1981-12-01

    The MHD high temperature air heater (HTAH) requires technology beyond the current state-of-the-art of industrial regenerative heaters. Specific aspects of HTAH technology which may find other application include refractory materials and valves resistant to the high temperature, corrosive, slag-bearing gas, materials resistant to cyclic thermal stresses, high temperature support structures for the cored brick bed, regenerative heater operating techniques for preventing accumulation of slag in the heater, and analytical tools for computing regenerative heater size, cost, and performance. Areas where HTAH technology may find application include acetylene/ethylene production processes, flash pyrolysis of coal, high temperature gas reactors, coal gasification processes, various metallurgical processes, waste incineration, and improvements to existing regenerator technology such as blast furnace stoves and glass tank regenerators.

  20. Evidence of Lunar Phase Influence on Global Surface Air Temperatures

    NASA Technical Reports Server (NTRS)

    Anyamba, Ebby; Susskind, Joel

    2000-01-01

    Intraseasonal oscillations appearing in a newly available 20-year record of satellite-derived surface air temperature are composited with respect to the lunar phase. Polar regions exhibit strong lunar phase modulation with higher temperatures occurs near full moon and lower temperatures at new moon, in agreement with previous studies. The polar response to the apparent lunar forcing is shown to be most robust in the winter months when solar influence is minimum. In addition, the response appears to be influenced by ENSO events. The highest mean temperature range between full moon and new moon in the polar region between 60 deg and 90 deg latitude was recorded in 1983, 1986/87, and 1990/91. Although the largest lunar phase signal is in the polar regions, there is a tendency for meridional equatorward progression of anomalies in both hemispheres so that the warning in the tropics occurs at the time of the new moon.

  1. Flight Simulator Platform Motion and Air Transport Pilot Training

    NASA Technical Reports Server (NTRS)

    Lee, Alfred T.; Bussolari, Steven R.

    1989-01-01

    The influence of flight simulator platform motion on pilot training and performance was examined In two studies utilizing a B-727-200 aircraft simulator. The simulator, located at Ames Research Center, Is certified by the FAA for upgrade and transition training in air carrier operations. Subjective ratings and objective performance of experienced B-727 pilots did not reveal any reliable effects of wide variations In platform motion de- sign. Motion platform variations did, however, affect the acquisition of control skill by pilots with no prior heavy aircraft flying experience. The effect was limited to pitch attitude control inputs during the early phase of landing training. Implications for the definition of platform motion requirements in air transport pilot training are discussed.

  2. Antarctic Sea ice variations and seasonal air temperature relationships

    NASA Technical Reports Server (NTRS)

    Weatherly, John W.; Walsh, John E.; Zwally, H. J.

    1991-01-01

    Data through 1987 are used to determine the regional and seasonal dependencies of recent trends of Antarctic temperature and sea ice. Lead-lag relationships involving regional sea ice and air temperature are systematically evaluated, with an eye toward the ice-temperature feedbacks that may influence climatic change. Over the 1958-1087 period the temperature trends are positive in all seasons. For the 15 years (l973-l987) for which ice data are available, the trends are predominantly positive only in winter and summer, and are most strongly positive over the Antarctic Peninsula. The spatially aggregated trend of temperature for this latter period is small but positive, while the corresponding trend of ice coverage is small but negative. Lag correlations between seasonal anomalies of the two variables are generally stronger with ice lagging the summer temperatures and with ice leading the winter temperatures. The implication is that summer temperatures predispose the near-surface waters to above-or below-normal ice coverage in the following fall and winter.

  3. 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

  4. 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.

  5. Stability limit of room air temperature of a VAV system

    SciTech Connect

    Matsuba, Tadahiko; Kamimura, Kazuyuki; Kasahara, Masato; Kimbara, Akiomi; Kurosu, Shigeru; Murasawa, Itaru; Hashimoto, Yukihiko

    1998-12-31

    To control heating, ventilating, and air-conditioning (HVAC) systems, it has been necessary to accept an analog system controlled mainly by proportional-plus-integral-plus-derivative (PID) action. However, when conventional PID controllers are replaced with new digital controllers by selecting the same PID parameters as before, the control loops have often got into hunting phenomena, which result in undamped oscillations. Unstable control characteristics (such as huntings) are thought to be one of the crucial problems faced by field operators. The PID parameters must be carefully selected to avoid instabilities. In this study, a room space is simulated as a thermal system that is air-conditioned by a variable-air-volume (VAV) control system. A dynamic room model without infiltration or exfiltration, which is directly connected to a simple air-handling unit without an economizer, is developed. To explore the possible existence of huntings, a numerical system model is formulated as a bilinear system with time-delayed feedback, and a parametric analysis of the stability limit is presented. Results are given showing the stability region affected by the selection of control and system parameters. This analysis was conducted to help us tune the PID controllers for optimal HVAC control.

  6. Controls of air temperature variability over an Alpine Glacier

    NASA Astrophysics Data System (ADS)

    Shaw, Thomas; Brock, Ben; Ayala, Álvaro; Rutter, Nick

    2016-04-01

    Near surface air temperature (Ta) is one of the most important controls on energy exchange between a glacier surface and the overlying atmosphere. However, not enough detail is known about the controls on Ta across a glacier due to sparse data availability. Recent work has provided insights into variability of Ta along glacier centre-lines in different parts of the world, yet there is still a limited understanding of off-centreline variability in Ta and how best to estimate it from distant off-glacier locations. We present a new dataset of distributed 2m Ta records for the Tsanteleina Glacier in Northwest Italy from July-September, 2015. Data provide detailed information of lateral (across-glacier) and centre-line variations in Ta, with ~20,000 hourly observations from 17 locations. The suitability of different vertical temperature gradients (VTGs) in estimating air temperature is considered under a range of meteorological conditions and from different forcing locations. A key finding is that local VTGs account for a lot of Ta variability under a broad range of climatic conditions. However, across-glacier variability is found to be significant, particularly for high ambient temperatures and for localised topographic depressions. The relationship of spatial Ta patterns with regional-scale reanalysis data and alternative Ta estimation methodologies are also presented. This work improves the knowledge of local scale Ta variations and their importance to melt modelling.

  7. High efficiency power generation from coal and wastes utilizing high temperature air combustion technology (Part 2: Thermal performance of compact high temperature air preheater and MEET boiler)

    SciTech Connect

    Iwahashi, Takashi; Kosaka, Hitoshi; Yoshida, Nobuhiro

    1998-07-01

    The compact high temperature air preheater and the MEET boiler, which are critical components of the MEET system, are the direct evolutions of the high temperature air combustion technology. Innovative hardware concept for a compact high temperature air preheater has been proposed, and preliminary experiment using the MEET-I high temperature air preheater based on this concept successfully demonstrated continuous high temperature air generation with almost no temperature fluctuation. A preliminary heat transfer calculation for the MEET boiler showed that regenerative combustion using high temperature air is quite effective for radiative heat transfer augmentation in a boiler, which will lead to significant downsizing of a boiler. The heat transfer characteristics in the MEET boiler were experimentally measured and the heat transfer promotion effect and the uniform heat transfer field were confirmed. Moreover, it was understood that excellent combustion with the low BTU gas of about 3,000 kcal/m{sup 3} was done.

  8. Solar assisted heat pump on air collectors: A simulation tool

    SciTech Connect

    Karagiorgas, Michalis; Galatis, Kostas; Tsagouri, Manolis; Tsoutsos, Theocharis; Botzios-Valaskakis, Aristotelis

    2010-01-15

    The heating system of the bioclimatic building of the Greek National Centre for Renewable Energy Sources (CRES) comprises two heating plants: the first one includes an air source heat pump, Solar Air Collectors (SACs) and a heat distribution system (comprising a fan coil unit network); the second one is, mainly, a geothermal heat pump unit to cover the ground floor thermal needs. The SAC configuration as well as the fraction of the building heating load covered by the heating plant are assessed in two operation modes; the direct (hot air from the collectors is supplied directly to the heated space) and the indirect mode (warm air from the SAC or its mixture with ambient air is not supplied directly to the heated space but indirectly into the evaporator of the air source heat pump). The technique of the indirect mode of heating aims at maximizing the efficiency of the SAC, saving electrical power consumed by the compressor of the heat pump, and therefore, at optimizing the coefficient of performance (COP) of the heat pump due to the increased intake of ambient thermal energy by means of the SAC. Results are given for three research objectives: assessment of the heat pump efficiency whether in direct or indirect heating mode; Assessment of the overall heating plant efficiency on a daily or hourly basis; Assessment of the credibility of the suggested simulation model TSAGAIR by comparing its results with the TRNSYS ones. (author)

  9. Modeling and simulation of metal-air batteries

    NASA Astrophysics Data System (ADS)

    Bevara, Vamsci Venkat

    Understanding of the transport phenomena in Li-air batteries is crucial for improving the performance and design of Li-air batteries. In this dissertation, the basic transport equations that govern the operation of Li-air batteries are derived by starting from the underlying mass and charge transport properties of the chemical species involved in the operation of the battery. Then, two approaches are presented to solve the transport equations. In the first approach, we use first-order approximations to derive a compact model for the discharge voltage of Li-air batteries with organic electrolyte. The model considers oxygen transport and volume change in the cathode, and Butler-Volmer kinetics at the anode and cathode electrodes, and is particularly useful to the fast prediction of the discharge voltage and specific capacities of Li-air batteries. In the second approach, we propose a finite-element model in which the basic transport equations are discretized over a finite space-time mesh and solved numerically to predict the battery characteristics under different discharge conditions and for different geometrical and physical parameters. Then, the transport equations are reexamined and improved to account for different pore microstructures, pore size distribution effects, and electron transport mechanisms through the discharge product. The different microstructures are simulated numerically and the performance of Li-air batteries is analyzed in each case. A novel hybrid model is introduced to explain the perceived transition from one microstructure to another.

  10. Simulation of urban and regional air pollution in Bangladesh

    NASA Astrophysics Data System (ADS)

    Muntaseer Billah Ibn Azkar, M. A.; Chatani, Satoru; Sudo, Kengo

    2012-04-01

    We have developed a regional scale air quality simulation using the Weather Research and Forecasting (WRF) - Community Multiscale Air Quality Model (CMAQ) to assess the suitability of such an advanced modeling system for predicting the air quality of Bangladesh and its surrounding region. The Regional Emission Inventory in Asia (REAS) was used as the emission input in this modeling approach. Both meteorological and chemical model performance were evaluated with observations including satellite data. Comparison between simulated and observed meteorological parameters revealed that the WRF can generate the necessary meteorological inputs for CMAQ. Comparison of observed and simulated concentrations of different air pollutants revealed that CMAQ greatly underestimates the concentrations of key pollutants. Comparison with satellite observations revealed that CMAQ reproduces the spatial distribution of NO2with some underestimation in Bangladesh and India. The simulated AOD and satellite-retrieved AOD showed good temporal and spatial agreement mutually, with a correlation coefficient of 0.58. Sensitivity simulation using higher horizontal resolution emission data made by re-gridding the REAS inventory with the population distribution improved the CMAQ performance. Nevertheless, CMAQ underestimated the pollutant concentrations in Dhaka. Uncertainties in the emission inventory and in the lack of time variation in emissions input mainly contributed to the model underestimation. Model predictions show that 36-72% PM10 and 15-60% PM2.5 in Dhaka might be contributed from brick kiln emissions in monthly average of January 2004. The chemical composition of PM2.5showed that the considerable amounts of secondary aerosols in Dhaka and carbonaceous components (particularly organic carbon) are most responsible for the model underestimation. Results suggest that improvements of emission inputs and more detailed sensitivity analysis of CMAQ model are important to assess the reliability

  11. Air Temperature estimation from Land Surface temperature and solar Radiation parameters

    NASA Astrophysics Data System (ADS)

    Lazzarini, Michele; Eissa, Yehia; Marpu, Prashanth; Ghedira, Hosni

    2013-04-01

    Air Temperature (AirT) is a fundamental parameter in a wide range of applications such as climate change studies, weather forecast, energy balance modeling, efficiency of Photovoltaic (PV) solar cells, etc. Air temperature data are generally obtained through regular measurements from meteorological stations. The distribution of these stations is normally sparse, so the spatial pattern of this parameter cannot be accurately estimated by interpolation methods. This work investigated the relationship between Air Temperature measured at meteorological stations and spatially contiguous measurements derived from Remote Sensing techniques, such as Land Surface Temperature (LST) maps, emissivity maps and shortwave radiation maps with the aim of creating a continuous map of AirT. For LST and emissivity, MSG-SEVIRI LST product from Land Surface Analysis Satellite Applications Facility (LSA-SAF) has been used. For shortwave radiation maps, an Artificial Neural Networks ensemble model has been developed and previously tested to create continuous maps from Global Horizontal Irradiance (GHI) point measurements, utilizing six thermal channels of MSG-SEVIRI. The testing sites corresponded to three meteorological stations located in the United Arab Emirates (UAE), where in situ measurements of Air Temperature were available. From the starting parameters, energy fluxes and net radiation have been calculated, in order to have information on the incoming and outgoing long-wave radiation and the incoming short-wave radiation. The preliminary analysis (day and Night measurements, cloud free) showed a strong negative correlation (0.92) between Outgoing long-wave radiation - GHI and LST- AirT, with a RMSE of 1.84 K in the AirT estimation from the initial parameters. Regression coefficients have been determined and tested on all the ground stations. The analysis also demonstrated the predominant impact of the incoming short-wave radiation in the AirT hourly variation, while the incoming

  12. Linking geomagnetic activity and polar surface air temperature variability

    NASA Astrophysics Data System (ADS)

    Seppala, Annika

    ERA-40 and ECMWF operational surface level air temperature (SAT) data sets from 1957 to 2006 were used to examine polar temperature variations during years with different levels of geomagnetic activity, as defined by the Ap index. Previous modelling work has suggested that NOx produced at high latitudes by energetic particle precipitation can eventually lead to detectable changes in polar SATs. We find that during winter months, ERA-40 and ECMWF polar SATs in years with high Ap index are different than in years with low Ap index; the differences are statistically significant at the 2-sigma level and range up to about ±4.5 K, de-pending on location. The temperature differences are larger when years with wintertime Sudden Stratospheric Warmings are excluded. Solar irradiance variations were taken into account in the analysis. Although using the re-analysis and operational data sets it was not possible to conclusively show that the polar SAT patterns are physically linked by geomagnetic activity, we conclude that geomagnetic activity likely plays a role in modulating polar wintertime surface air temperature patterns. The SAT results were tested against variation in the Quasi Biennial Oscillation (QBO), the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode n (SAM). The results suggested that these were not driving the observed polar SAT variability. However, significant uncertainty is introduced by the Northern Annular Mode (NAM) and we could not robustly exclude a chance linkage between sea surface temperature (SST) variability and geomagnetic activity. Examining the physical link between geomagnetic activity and polar surface temperature variability patterns using atmospheric models is an ongoing task.

  13. Multi-year simulations of air pollution in two cities

    NASA Astrophysics Data System (ADS)

    Zink, Katrin; Berchet, Antoine; Emmenegger, Lukas; Brunner, Dominik

    2016-04-01

    As more and more people are living in urban areas world wide, air quality monitoring and forecasting at the city scale becomes increasingly critical. Due to the proximity to sources and the complex, fine-scale structure of the flow and turbulence in the built environment, air pollutant concentrations vary strongly in cities both spatially and temporally. Studies assessing the effect of air pollution on human health would greatly benefit from accurate knowledge of individual exposure, but given the high variability of concentrations and the mobility of the population, this is a marvellous task requiring highly-resolved, city-wide information on air pollutant concentrations. The Swiss Nano-Tera project OpenSense II addresses these issues using statistical and physical modeling of air pollution at very high resolution combined with long-term air pollution measurements and mobile networks of low-cost sensors. In the framework of this project, we have set up the nested meteorology and dispersion model system GRAMM/GRAL the cities of Lausanne and Zurich and improved several computational aspects of the system. Using the mesoscale model GRAMM, we simulate the flow in a larger domain around the two cities at 100 m resolution taking the complex topography and influences of different land cover on surface-atmosphere exchange of heat and momentum into account. These flow fields serve as initial and boundary conditions for the nested model GRAL, which simulates the flow inside the city at building-resolving scale (5 m resolution) based on the Reynolds-Averaged-Navier-Stokes equations, and computes the transport and dispersion of air pollutants in a Lagrangian framework. For computational efficiency, both GRAMM and GRAL simulations are run for a fixed catalog of 1008 weather situations varying in terms of background wind speed, direction and stability. Hourly time-series of meteorology and air pollutants are constructed from these steady-state solutions by selecting, for each

  14. Generation of low-temperature air plasma for food processing

    NASA Astrophysics Data System (ADS)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  15. Numerical simulation of H2/air detonation using unstructured mesh

    NASA Astrophysics Data System (ADS)

    Togashi, Fumiya; Löhner, Rainald; Tsuboi, Nobuyuki

    2009-06-01

    To explore the capability of unstructured mesh to simulate detonation wave propagation phenomena, numerical simulation of H2/air detonation using unstructured mesh was conducted. The unstructured mesh has several adv- antages such as easy mesh adaptation and flexibility to the complicated configurations. To examine the resolution dependency of the unstructured mesh, several simulations varying the mesh size were conducted and compared with a computed result using a structured mesh. The results show that the unstructured mesh solution captures the detailed structure of detonation wave, as well as the structured mesh solution. To capture the detailed detonation cell structure, the unstructured mesh simulations required at least twice, ideally 5times the resolution of structured mesh solution.

  16. The Trends of Soil Temperature Change Associated with Air Temperature Change in Korea from 1973 to 2012

    NASA Astrophysics Data System (ADS)

    Lee, Bo-Hyun; Park, Byeong-Hak; Koh, Eun-Hee; Lee, Kang-Kun

    2015-04-01

    Examining long-term trends of the soil temperature can contribute to assessing subsurface thermal environment. The recent 40-year (1973-2012) meteorological data from 14 Korea Meteorological Administration (KMA) stations was analyzed in this study to estimate the temporal variations of air and soil temperatures (at depths 0.5 and 1.0m) in Korea and their relations. The information on regional characteristics of study sites was also collected to investigate the local and regional features influencing the soil temperature. The long-term increasing trends of both air and soil temperatures were estimated by using simple linear regression analysis. The air temperature rise and soil temperature rise were compared for every site to reveal the relation between air and soil temperature changes. In most sites, the proportion of soil temperature rise to air temperature rise was nearly one to one except a few sites. The difference between the air and soil temperature trends at those sites may be attributed to the combined effect of soil properties such as thermal diffusivity and soil moisture content. The impact of urbanization on the air and soil temperature was also investigated in this study. Establishment of the relationship between the air and soil temperatures can help predicting the soil temperature change in a region where no soil temperature data is obtained by using air temperature data. For rigorous establishment of the relationship between soil and air temperatures, more thorough investigation on the soil thermal properties is necessary through additional monitoring and accompanied validation of the proposed relations. Keywords : Soil temperature, Air temperature, Cross-correlation analysis, Soil thermal diffusivity, Urbanization effect Acknowledgement This work was supported by the research project of "Advanced Technology for Groundwater Development and Application in Riversides (Geowater+)" in "Water Resources Management Program (code 11 Technology Innovation C05

  17. CFD numerical simulation of air natural convection over a heated cylindrical surface

    NASA Astrophysics Data System (ADS)

    Flori, M.; Vîlceanu, L.

    2015-06-01

    In this study a CFD numerical simulation is used to describe the fluid flow and heat transfer in air surrounding a heated horizontal cylinder. The model is created in 2D space dimension involving a finite element solver of Navier-Stokes equations. As natural convection phenomenon is induced by a variable fluid density field with temperature rising, the Boussinesq approximation was coupled to the model.

  18. Identifying Modes of Temperature Variability Using AIRS Data.

    NASA Astrophysics Data System (ADS)

    Ruzmaikin, A.; Aumann, H. H.; Yung, Y.

    2007-12-01

    We use the Atmospheric Infrared Sounder (AIRS) and Advance Microwave Sounding Unit (AMSU) data obtained on Aqua spacecraft to study mid-tropospheric temperature variability between 2002-2007. The analysis is focused on daily zonal means of the AIRS channel at 2388 1/cm in the CO2 R-branch and the AMSU channel #5 in the 57 GHz Oxygen band, both with weighting function peaking in the mid-troposphere (400 mb) and the matching sea surface temperature from NCEP (Aumann et al., 2007). Taking into account the nonlinear and non- stationary behavior of the temperature we apply the Empirical Mode Decomposition (Huang et al., 1998) to better separate modes of variability. All-sky (cloudy) and clear sky, day and night data are analyzed. In addition to the dominant annual variation, which is nonlinear and latitude dependent, we identified the modes with higher frequency and inter-annual modes. Some trends are visible and we apply stringent criteria to test their statistical significance. References: Aumann, H. H., D. T. Gregorich, S. E. Broberg, and D. A. Elliott, Geophys. Res. Lett., 34, L15813, doi:10.1029/2006GL029191, 2007. Huang, N. E. Z. Shen, S. R. Long, M. C. Wu, H. H. Shih, Q. Zheng, N.-C. Yen, C. C. Tung, and H. H. Liu, Proc. R. Soc. Lond., A 454, 903-995, 1998.

  19. Simulating soybean canopy temperature as affected by weather variables and soil water potential

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.

    1982-01-01

    Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

  20. Simulation of SRAM SEU Sensitivity at Reduced Operating Temperatures

    NASA Technical Reports Server (NTRS)

    Sanathanamurthy, S.; Ramachandran, V.; Alles, M. L.; Reed, R. A.; Massengill, L. W.; Raman, A.; Turowski, M.; Mantooth, A.; Woods, B.; Barlow, M.; Moen, K.; Bellini, M.; Sutton, A.; Cressler, J. D.

    2009-01-01

    A new NanoTCAD-to-Spectre interface is applied to perform mixed-mode SEU simulations of an SRAM cell. Results using newly calibrated TCAD cold temperature substrate mobility models, and BSIM3 compact models extracted explicitly for the cold temperature designs, indicate a 33% reduction in SEU threshold for the range of temperatures simulated.

  1. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  2. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  3. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  4. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  5. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  6. Simulating sunflower canopy temperatures to infer root-zone soil water potential

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.; Idso, S. B.

    1983-01-01

    A soil-plant-atmosphere model for sunflower (Helianthus annuus L.), together with clear sky weather data for several days, is used to study the relationship between canopy temperature and root-zone soil water potential. Considering the empirical dependence of stomatal resistance on insolation, air temperature and leaf water potential, a continuity equation for water flux in the soil-plant-atmosphere system is solved for the leaf water potential. The transpirational flux is calculated using Monteith's combination equation, while the canopy temperature is calculated from the energy balance equation. The simulation shows that, at high soil water potentials, canopy temperature is determined primarily by air and dew point temperatures. These results agree with an empirically derived linear regression equation relating canopy-air temperature differential to air vapor pressure deficit. The model predictions of leaf water potential are also in agreement with observations, indicating that measurements of canopy temperature together with a knowledge of air and dew point temperatures can provide a reliable estimate of the root-zone soil water potential.

  7. Decadal power in land air temperatures: Is it statistically significant?

    NASA Astrophysics Data System (ADS)

    Thejll, Peter A.

    2001-12-01

    The geographical distribution and properties of the well-known 10-11 year signal in terrestrial temperature records is investigated. By analyzing the Global Historical Climate Network data for surface air temperatures we verify that the signal is strongest in North America and is similar in nature to that reported earlier by R. G. Currie. The decadal signal is statistically significant for individual stations, but it is not possible to show that the signal is statistically significant globally, using strict tests. In North America, during the twentieth century, the decadal variability in the solar activity cycle is associated with the decadal part of the North Atlantic Oscillation index series in such a way that both of these signals correspond to the same spatial pattern of cooling and warming. A method for testing statistical results with Monte Carlo trials on data fields with specified temporal structure and specific spatial correlation retained is presented.

  8. A new approach to quantifying soil temperature responses to changing air temperature and snow cover

    NASA Astrophysics Data System (ADS)

    Mackiewicz, Michael C.

    2012-08-01

    Seasonal snow cover provides an effective insulating barrier, separating shallow soil (0.25 m) from direct localized meteorological conditions. The effectiveness of this barrier is evident in a lag in the soil temperature response to changing air temperature. The causal relationship between air and soil temperatures is largely because of the presence or absence of snow cover, and is frequently characterized using linear regression analysis. However, the magnitude of the dampening effect of snow cover on the temperature response in shallow soils is obscured in linear regressions. In this study the author used multiple linear regression (MLR) with dummy predictor variables to quantify the degree of dampening between air and shallow soil temperatures in the presence and absence of snow cover at four Greenland sites. The dummy variables defining snow cover conditions were z = 0 for the absence of snow and z = 1 for the presence of snow cover. The MLR was reduced to two simple linear equations that were analyzed relative to z = 0 and z = 1 to enable validation of the selected equations. Compared with ordinary linear regression of the datasets, the MLR analysis yielded stronger coefficients of multiple determination and less variation in the estimated regression variables.

  9. Simulating canopy temperature for modelling heat stress in cereals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop models must be improved to account for the large effects of heat stress effects on crop yields. To date, most approaches in crop models use air temperature despite evidence that crop canopy temperature better explains yield reductions associated with high temperature events. This study presents...

  10. Simulation of air quality and cost to ventilate swine farrowing facilities in winter

    PubMed Central

    Park, Jae Hong; Peters, Thomas M.; Altmaier, Ralph; Sawvel, Russell A.; Anthony, T. Renée

    2016-01-01

    We developed a simulation model to study the effect of ventilation airflow rate with and without filtered recirculation on airborne contaminant concentrations (dust, NH3, CO, and CO2) for swine farrowing facilities. Energy and mass balance equations were used to simulate the indoor air quality and operational cost for a variety of ventilation conditions over a 3-month winter period, using time-varied outdoor temperature. The sensitivity of input and output parameters on indoor air quality and operational cost were evaluated. Significant factors affecting model output included mean winter temperature, generation rate of contaminants, pit-air-exchange ratio, and recirculation ratio. As mean outdoor temperature was decreased from −2.5 °C to −12.5 °C, total operational costs were increased from $872 to $1304. Dust generation rate affected dust concentrations linearly. When dust generation rates changed −50% and +100% from baseline, indoor dust concentrations were changed −50% and +100%, respectively. The selection of a pit-air-exchange ratio was found critical to NH3 concentration, but has little impact on other contaminants or cost. As the pit-air-exchange ratio was increased from 0.1 to 0.3, the NH3 concentration was increased by a factor of 1.5. The recirculation ratio affected both IAQ factors and total operational cost. As the recirculation ratio decreased to 0, inhalable and respirable dust concentrations, humidity, NH3 and CO2 concentrations decreased and total operational cost ($2216) was 104% more than with pit-fan-only ventilation ($1088). When the recirculation ratio was 1, the total operational cost was increased by $573 (53%) compared to pit-fan-only. Simulation provides a useful tool for examining the costs and benefits to installing common ventilation technology to CAFO and, ultimately, making sound management decisions. PMID:26937062

  11. Change point analysis of mean annual air temperature in Iran

    NASA Astrophysics Data System (ADS)

    Shirvani, A.

    2015-06-01

    The existence of change point in the mean of air temperature is an important indicator of climate change. In this study, Student's t parametric and Mann-Whitney nonparametric Change Point Models (CPMs) were applied to test whether a change point has occurred in the mean of annual Air Temperature Anomalies Time Series (ATATS) of 27 synoptic stations in different regions of Iran for the period 1956-2010. The Likelihood Ratio Test (LRT) was also applied to evaluate the detected change points. The ATATS of all stations except Bandar Anzali and Gorgan stations, which were serially correlated, were transformed to produce an uncorrelated pre-whitened time series as an input file for the CPMs and LRT. Both the Student's t and Mann-Whitney CPMs detected the change point in the ATATS of (a) Tehran Mehrabad, Abadan, Kermanshah, Khoramabad and Yazd in 1992, (b) Mashhad and Tabriz in 1993, (c) Bandar Anzali, Babolsar and Ramsar in 1994, (d) Kerman and Zahedan in 1996 at 5% significance level. The likelihood ratio test shows that the ATATS before and after detected change points in these 12 stations are normally distributed with different means. The Student's t and Mann-Whitney CPMs suggested different change points for individual stations in Bushehr, Bam, Shahroud, and Gorgan. However, the LRT confirmed the change points in these four stations as 1997, 1996, 1993, and 1996, respectively. No change points were detected in the remaining 11 stations.

  12. A simulator investigation of air-to-air combat maneuvering for tilt-rotor aircraft

    NASA Technical Reports Server (NTRS)

    Decker, William A.; Isleib, Douglas; Johns, John

    1989-01-01

    As part of the Marine Corps's development of employment methods and maneuver techniques for the V-22 Osprey tilt-rotor aircraft, a piloted simulation study of one-on-one air-combat maneuvering (ACM) was conducted at NASA Ames. In addition to V-22 ACM, the simulation provided an opportunity for a preliminary investigation of maneuver requirements for a possible armed-escort tilt-rotor aircraft. Results from the study indicate that the tilt-rotor's low-speed masking and high-speed dash capabilities significantly enhance its survivability against both fixed-wing and helicopter aggressors. Furthermore, the tilt-rotor's conversion capability and, in turn, the variety and extent of its maneuvering characteristics make it an effective air-combat aircraft.

  13. Modeling greenup date of dominant grass species in the Inner Mongolian Grassland using air temperature and precipitation data

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoqiu; Li, Jing; Xu, Lin; Liu, Li; Ding, Deng

    2014-05-01

    This work was undertaken to examine the combined effect of air temperature and precipitation during late winter and early spring on modeling greenup date of grass species in the Inner Mongolian Grassland. We used the traditional thermal time model and developed two revised thermal time models coupling air temperature and precipitation to simulate greenup date of three dominant grass species at six stations from 1983 to 2009. Results show that climatic controls on greenup date of grass species were location-specific. The revised thermal time models coupling air temperature and precipitation show higher simulation parsimony and efficiency than the traditional thermal time model for five of 11 data sets at Bayartuhushuo, Xilinhot and Xianghuangqi, whereas the traditional thermal time model indicates higher simulation parsimony and efficiency than the revised thermal time models coupling air temperature and precipitation for the other six data sets at E'ergunayouqi, Ewenkeqi and Chaharyouyihouqi. The mean root mean square error of the 11 models is 4.9 days. Moreover, the influence of late winter and early spring precipitation on greenup date seems to be stronger at stations with scarce precipitation than at stations with relatively abundant precipitation. From the mechanism perspectives, accumulated late winter and early spring precipitation may play a more important role as the precondition of forcing temperature than as the supplementary condition of forcing temperature in triggering greenup. Our findings suggest that predicting responses of grass phenology to global climate change should consider both thermal and moisture scenarios in some semiarid and arid areas.

  14. Computer-automated opponent for manned air-to-air combat simulations

    NASA Technical Reports Server (NTRS)

    Hankins, W. W., III

    1979-01-01

    Two versions of a real-time digital-computer program that operates a fighter airplane interactively against a human pilot in simulated air combat were evaluated. They function by replacing one of two pilots in the Langley differential maneuvering simulator. Both versions make maneuvering decisions from identical information and logic; they differ essentially in the aerodynamic models that they control. One is very complete, but the other is much simpler, primarily characterizing the airplane's performance (lift, drag, and thrust). Both models competed extremely well against highly trained U.S. fighter pilots.

  15. Assessing surface air temperature variability using quantile regression

    NASA Astrophysics Data System (ADS)

    Timofeev, A. A.; Sterin, A. M.

    2014-12-01

    Many researches in climate change currently involve linear trends, based on measured variables. And many of them only consider trends in mean values, whereas it is clear, that not only means, but also whole shape of distribution changes over time and requires careful assessment. For example extreme values including outliers may get bigger, while median has zero slope.Quantile regression provides a convenient tool, that enables detailed analysis of changes in full range of distribution by producing a vector of quantile trends for any given set of quantiles.We have applied quantile regression to surface air temperature observations made at over 600 weather stations across Russian Federation during last four decades. The results demonstrate well pronounced regions with similar values of significant trends in different parts of temperature value distribution (left tail, middle part, right tail). The uncertainties of quantile trend estimations for several spatial patterns of trends over Russia are estimated and analyzed for each of four seasons.For temperature trend estimation over vast territories, quantile regression is an effort consuming approach, but is more informative than traditional instrument, to assess decadal evolution of temperature values, including evolution of extremes.Partial support of ERA NET RUS ACPCA joint project between EU and RBRF 12-05-91656-ЭРА-А is highly appreciated.

  16. Comparison of Gravity Wave Temperature Variances from Ray-Based Spectral Parameterization of Convective Gravity Wave Drag with AIRS Observations

    NASA Technical Reports Server (NTRS)

    Choi, Hyun-Joo; Chun, Hye-Yeong; Gong, Jie; Wu, Dong L.

    2012-01-01

    The realism of ray-based spectral parameterization of convective gravity wave drag, which considers the updated moving speed of the convective source and multiple wave propagation directions, is tested against the Atmospheric Infrared Sounder (AIRS) onboard the Aqua satellite. Offline parameterization calculations are performed using the global reanalysis data for January and July 2005, and gravity wave temperature variances (GWTVs) are calculated at z = 2.5 hPa (unfiltered GWTV). AIRS-filtered GWTV, which is directly compared with AIRS, is calculated by applying the AIRS visibility function to the unfiltered GWTV. A comparison between the parameterization calculations and AIRS observations shows that the spatial distribution of the AIRS-filtered GWTV agrees well with that of the AIRS GWTV. However, the magnitude of the AIRS-filtered GWTV is smaller than that of the AIRS GWTV. When an additional cloud top gravity wave momentum flux spectrum with longer horizontal wavelength components that were obtained from the mesoscale simulations is included in the parameterization, both the magnitude and spatial distribution of the AIRS-filtered GWTVs from the parameterization are in good agreement with those of the AIRS GWTVs. The AIRS GWTV can be reproduced reasonably well by the parameterization not only with multiple wave propagation directions but also with two wave propagation directions of 45 degrees (northeast-southwest) and 135 degrees (northwest-southeast), which are optimally chosen for computational efficiency.

  17. Projected increases in near-surface air temperature over Ontario, Canada: a regional climate modeling approach

    NASA Astrophysics Data System (ADS)

    Wang, Xiuquan; Huang, Guohe; Liu, Jinliang

    2015-09-01

    As the biggest economy in Canada, the Province of Ontario is now suffering many consequences caused by or associated with global warming, such as frequent and intense heat waves, floods, droughts, and wind gust. Planning of mitigation and adaptation strategies against the changing climate, which requires a better understanding of possible future climate outcomes over the Province in the context of global warming, is of great interest to local policy makers, stakeholders, and development practitioners. Therefore, in this study, high-resolution projections of near-surface air temperature outcomes including mean, maximum, and minimum daily temperature over Ontario are developed, aiming at investigating how the global warming would affect the local climatology of the major cities as well as the spatial patterns of air temperature over the entire Province. The PRECIS modeling system is employed to carry out regional climate ensemble simulations driven by the boundary conditions of a five-member HadCM3-based perturbed-physics ensemble (i.e., HadCM3Q0, Q3, Q10, Q13, and Q15). The ensemble simulations are then synthesized through a Bayesian hierarchical model to develop probabilistic projections of future temperature outcomes with consideration of some uncertain parameters involved in the regional climate modeling process. The results suggest that there would be a consistent increasing trend in the near-surface air temperature with time periods from 2030s to 2080s. The most likely mean temperature in next few decades (i.e., 2030s) would be [-2, 2] °C in northern Ontario, [2, 6] °C in the middle, and [6, 12] °C in the south, afterwards the mean temperature is likely to keep rising by ~ 2 °C per 30-years period. The continuous warming across the Province would drive the lowest mean temperature up to 2 °C in the north and the highest mean temperature up to 16 °C in the south. In addition, the spread of the most likely ranges of future outcomes shows a consistent

  18. A high-fidelity batch simulation environment for integrated batch and piloted air combat simulation analysis

    NASA Technical Reports Server (NTRS)

    Goodrich, Kenneth H.; Mcmanus, John W.; Chappell, Alan R.

    1992-01-01

    A batch air combat simulation environment known as the Tactical Maneuvering Simulator (TMS) is presented. The TMS serves as a tool for developing and evaluating tactical maneuvering logics and to evaluate the tactical implications of perturbations to aircraft performance or supporting systems. The TMS is capable of simulating air combat between any number of engagement participants, with practical limits imposed by computer memory and processing power. Aircraft are modeled using equations of motion, control laws, aerodynamics and propulsive characteristics, and databases representative of a modern high-performance aircraft with and without thrust-vectoring capability are included. A Tactical Autopilot is implemented in the aircraft simulation model to convert guidance commands issued by computerized maneuvering logics in the form of desired angle-of-attack and wind axis-bank angle into inputs to the inner-loop control augmentation system of the aircraft.

  19. Air Surface Temperature Correlation with Greenhouse Gases by Using Airs Data Over Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Rajab, Jasim Mohammed; MatJafri, M. Z.; Lim, H. S.

    2014-08-01

    The main objective of this study is to develop algorithms for calculating the air surface temperature (AST). This study also aims to analyze and investigate the effects of greenhouse gases (GHGs) on the AST value in Peninsular Malaysia. Multiple linear regression is used to achieve the objectives of the study. Peninsular Malaysia has been selected as the research area because it is among the regions of tropical Southeast Asia with the greatest humidity, pockets of heavy pollution, rapid economic growth, and industrialization. The predicted AST was highly correlated ( R = 0.783) with GHGs for the 6-year data (2003-2008). Comparisons of five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the wet season (within 1.3 K). The in situ data ranged from 1 to 2 K. Validation results showed that AST ( R = 0.776-0.878) has values nearly the same as the observed AST from AIRS. We found that O3 during the wet season was indicated by a strongly positive beta coefficient (0.264-0.992) with AST. The CO2 yields a reasonable relationship with temperature with low to moderate beta coefficient (-0.065 to 0.238). The O3, CO2, and environmental variables experienced different seasonal fluctuations that depend on weather conditions and topography. The concentration of gases and pollution were the highest over industrial zones and overcrowded cities, and the dry season was more polluted compared with the wet season. These results indicate the advantage of using the satellite AIRS data and a correlation analysis to investigate the effect of atmospheric GHGs on AST over Peninsular Malaysia. An algorithm that is capable of retrieving Peninsular Malaysian AST in all weather conditions with total uncertainties ranging from 1 to 2 K was developed.

  20. Parallel finite element simulation of large ram-air parachutes

    NASA Astrophysics Data System (ADS)

    Kalro, V.; Aliabadi, S.; Garrard, W.; Tezduyar, T.; Mittal, S.; Stein, K.

    1997-06-01

    In the near future, large ram-air parachutes are expected to provide the capability of delivering 21 ton payloads from altitudes as high as 25,000 ft. In development and test and evaluation of these parachutes the size of the parachute needed and the deployment stages involved make high-performance computing (HPC) simulations a desirable alternative to costly airdrop tests. Although computational simulations based on realistic, 3D, time-dependent models will continue to be a major computational challenge, advanced finite element simulation techniques recently developed for this purpose and the execution of these techniques on HPC platforms are significant steps in the direction to meet this challenge. In this paper, two approaches for analysis of the inflation and gliding of ram-air parachutes are presented. In one of the approaches the point mass flight mechanics equations are solved with the time-varying drag and lift areas obtained from empirical data. This approach is limited to parachutes with similar configurations to those for which data are available. The other approach is 3D finite element computations based on the Navier-Stokes equations governing the airflow around the parachute canopy and Newtons law of motion governing the 3D dynamics of the canopy, with the forces acting on the canopy calculated from the simulated flow field. At the earlier stages of canopy inflation the parachute is modelled as an expanding box, whereas at the later stages, as it expands, the box transforms to a parafoil and glides. These finite element computations are carried out on the massively parallel supercomputers CRAY T3D and Thinking Machines CM-5, typically with millions of coupled, non-linear finite element equations solved simultaneously at every time step or pseudo-time step of the simulation.

  1. Optimization of solar cells for air mass zero operation and a study of solar cells at high temperatures, phase 3

    NASA Technical Reports Server (NTRS)

    Blakeslee, A. E.; Hovel, H. J.; Woodall, J. M.

    1977-01-01

    The etch-back epitaxy process is described for producing thin, graded composition GaAlAs layers. The palladium-aluminum contact system is discussed along with its associated problems. Recent solar cell results under simulated air mass zero light and at elevated temperatures are reported and the growth of thin polycrystalline GaAs films on foreign substrates is developed.

  2. Cyclic Oxidation of High-Temperature Alloy Wires in Air

    NASA Technical Reports Server (NTRS)

    Reigel, Marissa M.

    2004-01-01

    High-temperature alloy wires are proposed for use in seal applications for future re-useable space vehicles. These alloys offer the potential for improved wear resistance of the seals. The wires must withstand the high temperature environments the seals are subjected to as well as maintain their oxidation resistance during the heating and cooling cycles of vehicle re-entry. To model this, the wires were subjected to cyclic oxidation in stagnant air. of this layer formation is dependent on temperature. Slow growing oxides such as chromia and alumina are desirable. Once the oxide is formed it can prevent the metal from further reacting with its environment. Cyclic oxidation models the changes in temperature these wires will undergo in application. Cycling the temperature introduces thermal stresses which can cause the oxide layer to break off. Re-growth of the oxide layer consumes more metal and therefore reduces the properties and durability of the material. were used for cyclic oxidation testing. The baseline material, Haynes 188, has a Co base and is a chromia former while the other two alloys, Kanthal A1 and PM2000, both have a Fe base and are alumina formers. Haynes 188 and Kanthal A1 wires are 250 pm in diameter and PM2000 wires are 150 pm in diameter. The coiled wire has a total surface area of 3 to 5 sq cm. The wires were oxidized for 11 cycles at 1204 C, each cycle containing a 1 hour heating time and a minimum 20 minute cooling time. Weights were taken between cycles. After 11 cycles, one wire of each composition was removed for analysis. The other wire continued testing for 70 cycles. Post-test analysis includes X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) for phase identification and morphology.

  3. Equipartition and the Calculation of Temperature in Biomolecular Simulations.

    PubMed

    Eastwood, Michael P; Stafford, Kate A; Lippert, Ross A; Jensen, Morten Ø; Maragakis, Paul; Predescu, Cristian; Dror, Ron O; Shaw, David E

    2010-07-13

    Since the behavior of biomolecules can be sensitive to temperature, the ability to accurately calculate and control the temperature in molecular dynamics (MD) simulations is important. Standard analysis of equilibrium MD simulations-even constant-energy simulations with negligible long-term energy drift-often yields different calculated temperatures for different motions, however, in apparent violation of the statistical mechanical principle of equipartition of energy. Although such analysis provides a valuable warning that other simulation artifacts may exist, it leaves the actual value of the temperature uncertain. We observe that Tolman's generalized equipartition theorem should hold for long stable simulations performed using velocity-Verlet or other symplectic integrators, because the simulated trajectory is thought to sample almost exactly from a continuous trajectory generated by a shadow Hamiltonian. From this we conclude that all motions should share a single simulation temperature, and we provide a new temperature estimator that we test numerically in simulations of a diatomic fluid and of a solvated protein. Apparent temperature variations between different motions observed using standard estimators do indeed disappear when using the new estimator. We use our estimator to better understand how thermostats and barostats can exacerbate integration errors. In particular, we find that with large (albeit widely used) time steps, the common practice of using two thermostats to remedy so-called hot solvent-cold solute problems can have the counterintuitive effect of causing temperature imbalances. Our results, moreover, highlight the utility of multiple-time step integrators for accurate and efficient simulation. PMID:26615934

  4. Study of Ram-air Heat Exchangers for Reducing Turbine Cooling-air Temperature of a Supersonic Aircraft Turbojet Engine

    NASA Technical Reports Server (NTRS)

    Diaguila, Anthony J; Livingood, John N B; Eckert, Ernst R G

    1956-01-01

    The sizes and weights of the cores of heat exchangers were determined analytically for possible application for reducing turbine cooling-air temperatures of an engine designed for a Mach number of 2.5 and an altitude The sizes and weights of the cores of heat exchangers were determined analytically for possible application for reducing turbine cooling-air temperatures of an engine designed for a Mach number of 2.5 and an altitude of 70,000 feet. A compressor-bleed-air weight flow of 2.7 pounds per second was assumed for the coolant; ram air was considered as the other fluid. Pressure drops and inlet states of both fluids were prescribed, and ranges of compressor-bleed-air temperature reductions and of the ratio of compressor-bleed to ram-air weight flows were considered.

  5. Experimental investigation of ultraviolet laser induced plasma density and temperature evolution in air

    SciTech Connect

    Thiyagarajan, Magesh; Scharer, John

    2008-07-01

    We present measurements and analysis of laser induced plasma neutral densities and temperatures in dry air by focusing 200 mJ, 10 MW high power, 193 nm ultraviolet ArF (argon fluoride) laser radiation to a 30 {mu}m radius spot size. We examine these properties that result from multiphoton and collisional cascade processes for pressures ranging from 40 Torr to 5 atm. A laser shadowgraphy diagnostic technique is used to obtain the plasma electron temperature just after the shock front and this is compared with optical emission spectroscopic measurements of nitrogen rotational and vibrational temperatures. Two-color laser interferometry is employed to measure time resolved spatial electron and neutral density decay in initial local thermodynamic equilibrium (LTE) and non-LTE conditions. The radiating species and thermodynamic characteristics of the plasma are analyzed by means of optical emission spectroscopy (OES) supported by SPECAIR, a special OES program for air constituent plasmas. Core plasma rotational and vibrational temperatures are obtained from the emission spectra from the N{sub 2}C-B(2+) transitions by matching the experimental spectrum results with the SPECAIR simulation results and the results are compared with the electron temperature just behind the shock wave. The plasma density decay measurements are compared with a simplified electron density decay model that illustrates the dominant three-and two-body recombination terms with good correlation.

  6. Experimental investigation of ultraviolet laser induced plasma density and temperature evolution in air

    NASA Astrophysics Data System (ADS)

    Thiyagarajan, Magesh; Scharer, John

    2008-07-01

    We present measurements and analysis of laser induced plasma neutral densities and temperatures in dry air by focusing 200 mJ, 10 MW high power, 193 nm ultraviolet ArF (argon fluoride) laser radiation to a 30 μm radius spot size. We examine these properties that result from multiphoton and collisional cascade processes for pressures ranging from 40 Torr to 5 atm. A laser shadowgraphy diagnostic technique is used to obtain the plasma electron temperature just after the shock front and this is compared with optical emission spectroscopic measurements of nitrogen rotational and vibrational temperatures. Two-color laser interferometry is employed to measure time resolved spatial electron and neutral density decay in initial local thermodynamic equilibrium (LTE) and non-LTE conditions. The radiating species and thermodynamic characteristics of the plasma are analyzed by means of optical emission spectroscopy (OES) supported by SPECAIR, a special OES program for air constituent plasmas. Core plasma rotational and vibrational temperatures are obtained from the emission spectra from the N2C-B(2+) transitions by matching the experimental spectrum results with the SPECAIR simulation results and the results are compared with the electron temperature just behind the shock wave. The plasma density decay measurements are compared with a simplified electron density decay model that illustrates the dominant three-and two-body recombination terms with good correlation.

  7. Propagation Of Error And The Reliability Of Global Air Temperature Projections

    NASA Astrophysics Data System (ADS)

    Frank, P.

    2013-12-01

    General circulation model (GCM) projections of the impact of rising greenhouse gases (GHGs) on globally averaged annual surface air temperatures are a simple linear extrapolation of GHG forcing, as indicated by their accurate simulation using the equation, ΔT = a×33K×[(F0+∑iΔFi)/F0], where F0 is the total GHG forcing of projection year zero, ΔFi is the increment of GHG forcing in the ith year, and a is a variable dimensionless fraction that follows GCM climate sensitivity. Linearity of GCM air temperature projections means that uncertainty propagates step-wise as the root-sum-square of error. The annual average error in total cloud fraction (TCF) resulting from CMIP5 model theory-bias is ×12%, equivalent to ×5 Wm-2 uncertainty in the energy state of the projected atmosphere. Propagated uncertainty due to TCF error is always much larger than the projected globally averaged air temperature anomaly, and reaches ×20 C in a centennial projection. CMIP5 GCMs thus have no predictive value.

  8. 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

  9. Integration of Linear Dynamic Emission and Climate Models with Air Traffic Simulations

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Ng, Hok K.; Chen, Neil Y.

    2012-01-01

    Future air traffic management systems are required to balance the conflicting objectives of maximizing safety and efficiency of traffic flows while minimizing the climate impact of aviation emissions and contrails. Integrating emission and climate models together with air traffic simulations improve the understanding of the complex interaction between the physical climate system, carbon and other greenhouse gas emissions and aviation activity. This paper integrates a national-level air traffic simulation and optimization capability with simple climate models and carbon cycle models, and climate metrics to assess the impact of aviation on climate. The capability can be used to make trade-offs between extra fuel cost and reduction in global surface temperature change. The parameters in the simulation can be used to evaluate the effect of various uncertainties in emission models and contrails and the impact of different decision horizons. Alternatively, the optimization results from the simulation can be used as inputs to other tools that monetize global climate impacts like the FAA s Aviation Environmental Portfolio Management Tool for Impacts.

  10. Subseasonal variability of North American wintertime surface air temperature

    NASA Astrophysics Data System (ADS)

    Lin, Hai

    2015-09-01

    Using observational pentad data of the recent 34 Northern Hemisphere extended winters, subseasonal variability of surface air temperature (SAT) over North America is analyzed. The four leading modes of subseasonal SAT variability, that are identified with an empirical orthogonal function (EOF) analysis, account for about 60% of the total variance. The first (EOF1) and second (EOF2) modes are independent of other modes, and thus are likely controlled by distinct processes. The third (EOF3) and fourth (EOF4) modes, however, tend to have a phase shift to each other in space and time, indicating that part of their variability is related to a common process and represent a propagating pattern over North America. Lagged regression analysis is conducted to identify the precursors of large-scale atmospheric circulation for each mode a few pentads in advance, and to understand the processes that influence the subseasonal SAT variability and the predictability signal sources. EOF1 is found to be closely related to the Pacific-North American (PNA) circulation pattern and at least part of its variability is preceded by the East Asian cold surge. The cold surge leads to low-level convergence and enhanced convection in the tropical central Pacific which in turn induces the PNA. EOF2 tends to oscillate at a period of about 70 days, and is influenced by the low-frequency component of the Madden-Julian Oscillation (MJO). On the other hand, EOF3 and EOF4 are connected to the high-frequency part of the MJO which has a period range of 30-50 days. These findings would help understanding the mechanisms of subseasonal surface air temperature variability in North America and improving weather predictions on a subseasonal time scale.

  11. 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.

  12. Estimating Air Temperature over the Tibetan Plateau Using MODIS Data

    NASA Astrophysics Data System (ADS)

    Huang, Fangfang; Ma, Weiqiang; Ma, Yaoming; Li, Maoshan; Hu, Zeyong

    2016-04-01

    Time series of MODIS land surface temperature (LST) data and normalized difference vegetation index (NDVI) data, combined with digital elevation model (DEM) and meterological data for 2001-2012, were used to estimate and map the spatial distribution of monthly mean air temperature over the Tibatan Plateau (TP). Time series and regression analysis of monthly mean land surface temperature (Ts) and air temperature (Ta) were both conducted by ordinary liner regression (OLR) and geographical weighted regression (GWR) methods. Analysis showed that GWR method had much better result (Adjusted R2 > 0.79, root mean square error (RMSE) is between 0.51° C and 1.12° C) for estimating Ta than OLR method. The GWR model, with MODIS LST, NDVI and altitude as independent variables, was used to estimate Ta over the Tibetan Plateau. All GWR models in each month were tested by F-test with significant level of α=0.01 and the regression coefficients were all tested by T-test with significant level of α=0.01. This illustrated that Ts, NDVI and altitude play an important role on estimating Ta over the Tibetan Plateau. Finally, the major conclusions are as follows: (1) GWR method has higher accuracy for estimating Ta than OLR (Adjusted R2=0.40˜0.78, RMSE=1.60˜4.38° C), and the Ta control precision can be up to 1.12° C. (2) Over the Northern TP, the range of Ta variation in January is -29.28 ˜ -5.0° C, and that in July is -0.53 ˜ 14.0° C. Ta in summer half year (from May to October) is between -15.92 ˜ 14.0° C. From October on, 0° C isothermal level is gradually declining from the altitude of 4˜5 kilometers, and hits the bottom with altitude of 3200 meters in December, and Ta is all under 0° C in January. 10° C isothermal level gradually starts rising from the altitude of 3200 meters from May, and reaches the highest level with altitude of 4˜5 kilometers in July. In addition, Ta in south slope of the Tanggula Mountains is obviously higher than that in the north slope. Ta

  13. Simulation of intense microwave pulse propagation in air breakdown environment

    NASA Technical Reports Server (NTRS)

    Kuo, S. P.; Zhang, Y. S.

    1991-01-01

    An experiment is conducted to examine the tail erosion phenomenon which occurs to an intense microwave pulse propagating in air breakdown environment. In the experiment, a 1 MW microwave pulse (1.1 microsec) is transmitted through a large plexiglas chamber filled with dry air at about 1-2 torr pressure. Two different degrees of tail erosion caused by two different mechanisms are identified. This experimental effort leads to the understanding of the fundamental behavior of tail erosion and provides a data base for validating the theoretical model. A theoretical model based on two coupled partial differential equations is established to describe the propagation on an intense microwave pulse in air breakdown environment. One is derived from the Poynting theorem, and the other one is the rate equation of electron density. A semi-empirical formula of the ionization frequency is adopted for this model. A transformation of these two equations to local time frame of reference is introduced so that they can be solved numerically with considerably reduced computation time. This model is tested by using it to perform the computer simulation of the experiment. The numerical results are shown to agree well with the experimental results.

  14. High temperature behavior of simulated mixed nitrides

    NASA Astrophysics Data System (ADS)

    Baranov, V. G.; Lunev, A. V.; Mikhalchik, V. V.; Tenishev, A. V.; Shornikov, D. P.

    2016-04-01

    Specimen of uranium-based mixed nitrides were synthesized by high-temperature nitriding of metal powder. To investigate thermal stability, samples were annealed at high temperature in a helium atmosphere. During these experiments, the effect of increasing the exposure temperature is studied. Raising the exposure temperature results in a multifold increase of mass loss. A comparison with data on pure uranium nitride shows that increasing the complexity of the nitride systems also results in higher mass loss. Later microscopic investigation of test samples revealed that metal precipitates may be found only on the surface of test samples. Electron probe micro-analysis indicates these precipitates to be uranium metal. Nevertheless, compared to pure uranium nitride, uranium-based mixed nitrides exhibit active evaporation at lower temperatures

  15. What matters most: Are summer stream temperatures more sensitive to changing air temperature, changing discharge, or changing riparian vegetation under future climates?

    NASA Astrophysics Data System (ADS)

    Diabat, M.; Haggerty, R.; Wondzell, S. M.

    2012-12-01

    We investigated stream temperature responses to changes in both air temperature and stream discharge projected for 2040-2060 from downscaled GCMs and changes in the height and canopy density of streamside vegetation. We used Heat Source© calibrated for a 37 km section of the Middle Fork John Day River located in Oregon, USA. The analysis used the multiple-variable-at-a-time (MVAT) approach to simulate various combinations of changes: 3 levels of air warming, 5 levels of stream flow (higher and lower discharges), and 6 types of streamside vegetation. Preliminary results show that, under current discharge and riparian vegetation conditions, projected 2 to 4 °C increase in air temperature will increase the 7-day Average Daily Maximum Temperature (7dADM) by 1 to 2 °C. Changing stream discharge by ±30% changes stream temperature by ±0.5 °C, and the influence of changing discharge is greatest when the stream is poorly shaded. In contrast, the 7dADM could change by as much as 11°C with changes in riparian vegetation from unshaded conditions to heavily shaded conditions along the study section. The most heavily shaded simulations used uniformly dense riparian vegetation over the full 37-km reach, and this vegetation was composed of the tallest trees and densest canopies that can currently occur within the study reach. While this simulation represents an extreme case, it does suggest that managing riparian vegetation to substantially increase stream shade could decrease 7dADM temperatures relative to current temperatures, even under future climates when mean air temperatures have increased from 2 to 4 °C.

  16. Nonparametric Stochastic Hydroclimate Simulation for Water Temperature Modeling in Lake Shasta

    NASA Astrophysics Data System (ADS)

    Rajagopalan, B.; Sapin, J. R.; Saito, L.

    2014-12-01

    Reservoir managers on the Sacramento River are required by law to provide artificial cold water habitat downstream for endangered winter-run Chinook salmon. This is enabled at Shasta Lake via a temperature control device installed on Shasta Dam that allows selective withdrawal of reservoir water from different elevations and temperatures. Risk based decision making and planning requires ability to generate ensemble of water temperatures released from the lake - especially when the planning needs to be made under future climate conditions. To this end, we developed a stochastic hydroclimate simulation method that generates ensembles of influent lake streamflow, influent stream temperatures and air temperature over the lake. These, combined with a two-dimensional hydrodynamic model, CE-QUAL-W2 provides ensembles of water temperatures released from the various levels of the lake. A nonparametric K-nearest neighbor based disaggregation method is used to generate streamflow ensembles at five streams entering the lake. Then, conditionally the temperatures of water entering the lake and the air temperature over the lake are also simulated. The W2 model generates lake temperatures. The disaggregation method is also modified to generate streamflows consistent with wet and dry conditions and consequently, the lake temperature scenarios, enabling the water managers to assess various decision options.

  17. The analysis of a generic air-to-air missile simulation model

    NASA Technical Reports Server (NTRS)

    Kaplan, Joseph A.; Chappell, Alan R.; Mcmanus, John W.

    1994-01-01

    A generic missile model was developed to evaluate the benefits of using a dynamic missile fly-out simulation system versus a static missile launch envelope system for air-to-air combat simulation. This paper examines the performance of a launch envelope model and a missile fly-out model. The launch envelope model bases its probability of killing the target aircraft on the target aircraft's position at the launch time of the weapon. The benefits gained from a launch envelope model are the simplicity of implementation and the minimal computational overhead required. A missile fly-out model takes into account the physical characteristics of the missile as it simulates the guidance, propulsion, and movement of the missile. The missile's probability of kill is based on the missile miss distance (or the minimum distance between the missile and the target aircraft). The problems associated with this method of modeling are a larger computational overhead, the additional complexity required to determine the missile miss distance, and the additional complexity of determining the reason(s) the missile missed the target. This paper evaluates the two methods and compares the results of running each method on a comprehensive set of test conditions.

  18. Topographic and spatial impacts of temperature inversions on air quality using mobile air pollution surveys.

    PubMed

    Wallace, Julie; Corr, Denis; Kanaroglou, Pavlos

    2010-10-01

    We investigated the spatial and topographic effects of temperature inversions on air quality in the industrial city of Hamilton, located at the western tip of Lake Ontario, Canada. The city is divided by a 90-m high topographic scarp, the Niagara Escarpment, and dissected by valleys which open towards Lake Ontario. Temperature inversions occur frequently in the cooler seasons, exacerbating the impact of emissions from industry and traffic. This study used pollution data gathered from mobile monitoring surveys conducted over a 3-year period, to investigate whether the effects of the inversions varied across the city. Temperature inversions were identified with vertical temperature data from a meteorological tower located within the study area. We divided the study area into an upper and lower zone separated by the Escarpment and further into six zones, based on location with respect to the Escarpment and industrial and residential areas, to explore variations across the city. The results identified clear differences in the responses of nitrogen dioxide (NO(2)) and fine particulate matter (PM2.5) to temperature inversions, based on the topographic and spatial criteria. We found that pollution levels increased as the inversion strengthened, in the lower city. However, the results also suggested that temperature inversions identified in the lower city were not necessarily experienced in the upper city with the same intensity. Further, pollution levels in the upper city appeared to decrease as the inversion deepened in the lower city, probably because of an associated change in prevailing wind direction and lower wind speeds, leading to decreased long-range transport of pollutants. PMID:20705328

  19. Tuneable polaritonics at room temperature with strongly coupled Tamm plasmon polaritons in metal/air-gap microcavities

    NASA Astrophysics Data System (ADS)

    Grossmann, C.; Coulson, C.; Christmann, G.; Farrer, I.; Beere, H. E.; Ritchie, D. A.; Baumberg, J. J.

    2011-06-01

    We report strong coupling between Tamm plasmons and excitons in III-V quantum wells at room temperature in ultracompact sample designs. A high refractive index contrast air-gap mirror together with optical Tamm states at a metal/semiconductor interface tightly confines the intracavity field leading to substantial local field enhancements. Angular-resolved reflectivity spectra give clear evidence for anticrossing in the dispersion relation. Room temperature Rabi splittings of 10 meV are found in excellent agreement with simulations. Electrical control of the polariton modes is realized without need for doped mirror layers. Such air-gap microcavities open innovative possibilites for electrically tunable microcavities and polaritonic microelectromechanics.

  20. Sea surface temperature anomalies, planetary waves, and air-sea feedback in the middle latitudes

    NASA Technical Reports Server (NTRS)

    Frankignoul, C.

    1985-01-01

    Current analytical models for large-scale air-sea interactions in the middle latitudes are reviewed in terms of known sea-surface temperature (SST) anomalies. The scales and strength of different atmospheric forcing mechanisms are discussed, along with the damping and feedback processes controlling the evolution of the SST. Difficulties with effective SST modeling are described in terms of the techniques and results of case studies, numerical simulations of mixed-layer variability and statistical modeling. The relationship between SST and diabatic heating anomalies is considered and a linear model is developed for the response of the stationary atmosphere to the air-sea feedback. The results obtained with linear wave models are compared with the linear model results. Finally, sample data are presented from experiments with general circulation models into which specific SST anomaly data for the middle latitudes were introduced.

  1. The impact of different cooling strategies on urban air temperatures: the cases of Campinas, Brazil and Mendoza, Argentina

    NASA Astrophysics Data System (ADS)

    Alchapar, Noelia Liliana; Cotrim Pezzuto, Claudia; Correa, Erica Norma; Chebel Labaki, Lucila

    2016-07-01

    This paper describes different ways of reducing urban air temperature and their results in two cities: Campinas, Brazil—a warm temperate climate with a dry winter and hot summer (Cwa), and Mendoza, Argentina—a desert climate with cold steppe (BWk). A high-resolution microclimate modeling system—ENVI-met 3.1—was used to evaluate the thermal performance of an urban canyon in each city. A total of 18 scenarios were simulated including changes in the surface albedo, vegetation percentage, and the H/W aspect ratio of the urban canyons. These results revealed the same trend in behavior for each of the combinations of strategies evaluated in both cities. Nevertheless, these strategies produce a greater temperature reduction in the warm temperate climate (Cwa). Increasing the vegetation percentage reduces air temperatures and mean radiant temperatures in all scenarios. In addition, there is a greater decrease of urban temperature with the vegetation increase when the H/W aspect ratio is lower. Also, applying low albedo on vertical surfaces and high albedo on horizontal surfaces is successful in reducing air temperatures without raising the mean radiant temperature. The best combination of strategies—60 % of vegetation, low albedos on walls and high albedos on pavements and roofs, and 1.5 H/W—could reduce air temperatures up to 6.4 °C in Campinas and 3.5 °C in Mendoza.

  2. Simulations of a cold-air pool associated with elevated wintertime ozone in the Uintah Basin, Utah

    NASA Astrophysics Data System (ADS)

    Neemann, E. M.; Crosman, E. T.; Horel, J. D.; Avey, L.

    2015-01-01

    Numerical simulations are used to investigate the meteorological characteristics of the 31 January-6 February 2013 cold-air pool in the Uintah Basin, Utah, and the resulting high ozone concentrations. Flow features affecting cold-air pools and air quality in the Uintah Basin are studied, including the following: penetration of clean air into the basin from across the surrounding mountains, elevated easterlies within the inversion layer, and thermally driven slope and valley flows. The sensitivity of the boundary layer structure to snow cover variations and cloud microphysics are also examined. Snow cover increases boundary layer stability by enhancing the surface albedo, reducing the absorbed solar insolation at the surface, and lowering near-surface air temperatures. Snow cover also increases ozone levels by enhancing solar radiation available for photochemical reactions. Ice-dominant clouds enhance cold-air pool strength compared to liquid-dominant clouds by increasing nocturnal cooling and decreasing longwave cloud forcing.

  3. Improving target orientation discrimination performance in air-to-air flight simulation

    NASA Astrophysics Data System (ADS)

    Serfoss, Gary Lee

    Despite significant advances, state-of-the-art image projectors still lack the ability to display object detail equivalent to a 20/20 visual acuity capability. Unfortunately, for proper close-in air combat training in a flight simulator, this level of detail is necessary if a pilot is to accurately determine the orientation of another aircraft at realistic ranges. This investigation evaluates a possible interim solution to this problem that could be implemented until projectors are developed that can provide adequate resolution. The research methodology involves enlarging the "enemy" aircraft by various amounts as a function of distance-resulting in an aircraft that still always gets smaller as it moves farther away, but just not as quickly as a "non-enlarged" target. The results from 20 male F-16 pilots provided the distances where the orientation of aircraft in the simulator could be determined as well as similar aircraft under "real-world" conditions. By using these distances, it was possible to determine the amount of magnification needed to identify necessary details of the simulated aircraft at the same distances as they are under "real-world" conditions. The final product is a magnification curve that can be used to modify how the simulated target changes in size as a function of distance. Results seem to indicate that performance in the simulator might be enhanced to match real flying conditions without unacceptably (or perhaps even noticeably) altering the size of the target. These results should be applicable (with minor modification) to many other aircraft and perhaps ground targets as well. Furthermore, it is anticipated that application can be made beyond flight simulation to other types of simulation where performance is also currently inhibited due to lack of display resolution.

  4. Combustion and gasification characteristics of pulverized coal using high-temperature air

    SciTech Connect

    Hanaoka, R.; Nakamura, M.; Kiga, T.; Kosaka, H.; Iwahashi, T.; Yoshikawa, K.; Sakai, M.; Muramatsu, K.; Mochida, S.

    1998-07-01

    In order to confirm performance of high-temperature-air combusting of pulverized coal, laboratory-scale combustion and gasification tests of coal were conducted changing air temperature and oxygen concentration in the air. Theses were conducted in a drop tube furnace of 200mm in inside diameter and 2,000mm in length. The furnace was heated by ceramic heater up to 1,300 C. A high-temperature air preheater utilizing the HRS (High Cycle Regenerative Combustion System) was used to obtain high-temperature combustion air. As the results, NOx emission was reduced when pulverized coal was fired with high-temperature-air. On the other hand, by lower oxygen concentration in combustion air diluted by nitrogen, NOx emission slightly decreased while became higher under staging condition.

  5. I-Tree Temperature: An Object Oriented Model on Urban Microclimate Simulation

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Endreny, T. A.; Nowak, D.

    2014-12-01

    Air temperature and humidity are two of the most critical meteorological variables in relation to biological and hydrological processes, human thermal comfort, ecosystems, and energy consumption on heating and cooling. Yang et al. (2013) developed a physically-based analytical spatial air temperature and humidity (PASATH) model to simulate microclimate of urban area. This model can provide spatial time series maps of air temperature, humidity, latent heat flux, and sensible heat flux in spatial resolution of one hundred meters and temporal resolution of one hour. PASATH performed satisfactorily given its intended simplicity and low requirement on the inputs. The USDA Forest Service and the Davey Institute developed i-Tree Temperature model based on the PASATH model to complement the strength of the i-Tree suite of tools for urban forest analyses of structure and ecosystem services. The i-Tree temperature model was written in C++ with Objected Oriented Design (OOD). Improved functions were added to improve the simulation of heat flux resistances; new classes were incorporated to better control the inputs and outputs; new model structure was designed to advance the simulation efficiency; inputs formating were optimized to make it more user friendly. The model will be publicly available as a new i-Tree function in 2015 by the USDA Forest Service and the Davey Institute. It can be used to study urban heat island effects and investigate land cover and hydrology based mitigation methods; the simulated spatial maps of air temperature and humidity can provide inputs for other environmental models, including atmospheric models, ecosystem models, and hydrology models, for scientific studies of environmental and human health.

  6. 40 CFR 86.162-03 - Approval of alternative air conditioning test simulations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... alternative air conditioning test simulations. (a) Upon petition from a manufacturer or upon the Agency's own initiative, the Administrator will approve a simulation of the environmental cell for air conditioning test... the tailpipe emissions, air conditioning compressor load, and fuel economy. (2) For any...

  7. 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

  8. How the Plant Temperature Links to the Air Temperature in the Desert Plant Artemisia ordosica

    PubMed Central

    Yu, Ming-Han; Ding, Guo-Dong; Gao, Guang-Lei; Sun, Bao-Ping; Zhao, Yuan-Yuan; Wan, Li; Wang, De-Ying; Gui, Zi-Yang

    2015-01-01

    Plant temperature (Tp) is an important indicator of plant health. To determine the dynamics of plant temperature and self-cooling ability of the plant, we measured Tp in Artemisia ordosica in July, in the Mu Us Desert of Northwest China. Related factors were also monitored to investigate their effects on Tp, including environmental factors, such as air temperature (Ta), relative humidity, wind speed; and physiological factors, such as leaf water potential, sap flow, and water content. The results indicate that: 1) Tp generally changes in conjunction with Ta mainly, and varies with height and among the plant organs. Tp in the young branches is most constant, while it is the most sensitive in the leaves. 2) Correlations between Tp and environmental factors show that Tp is affected mainly by Ta. 3) The self-cooling ability of the plant was effective by midday, with Tp being lower than Ta. 4) Increasing sap flow and leaf water potential showed that transpiration formed part of the mechanism that supported self-cooling. Increased in water conductance and specific heat at midday may be additional factors that contribute to plant cooling ability. Therefore, our results confirmed plant self-cooling ability. The response to high temperatures is regulated by both transpiration speed and an increase in stem water conductance. This study provides quantitative data for plant management in terms of temperature control. Moreover, our findings will assist species selection with taking plant temperature as an index. PMID:26280557

  9. Fine-resolution model simulations of California air quality

    NASA Astrophysics Data System (ADS)

    Kim, S.; Trainer, M.; Angevine, W. M.; Lee, S.; Alvarez, R. J., II; Baidar, S.; Frost, G. J.; Hardesty, R.; Langford, A. O.; McKeen, S. A.; Oetjen, H.; Pollack, I. B.; Ryerson, T. B.; Senff, C. J.; Sinreich, R.; Volkamer, R.

    2010-12-01

    The purpose of our study is to improve the understanding of tropospheric ozone, its precursors, and their temporal changes over California. We simulate California air quality using the Weather Research and Forecasting - Chemistry (WRF-Chem) model with input from the US EPA's 2005 National Emission Inventory (NEI05) for July 2009 and spring-summer 2010. The model’s nested domain includes all of California at 4 x 4 km2 horizontal resolution. These simulation periods were chosen because of the availability of measurements from the pre-CalNex and CalNex field campaigns. The WRF-Chem simulations are evaluated with observations of ozone curtains by the TOPAZ lidar and in-situ measurements of numerous trace species collected on NOAA aircraft during these deployments. The WRF-Chem meteorological predictions are also compared with surface stations and wind profiler data. These model-measurement comparisons allow us to test the sensitivity of WRF-Chem to initial and boundary conditions, land-surface models, grid configurations, and emission inventory. Using the model evaluated with these observations, we investigate the importance of transport mechanisms and emission changes on tropospheric ozone levels above California.

  10. Numerical Simulation of Turbulent Propane-Air Combustion with Non-Homogeneous Reactants

    NASA Astrophysics Data System (ADS)

    Haworth, D.; Cuenot, B.; Poinsot, T.; Blint, R.

    1998-11-01

    Two-dimensional numerical simulations of turbulent propane-air combustion have been performed including complex chemistry and realistic molecular transport. The aerothermochemical conditions simulated (reactant temperature and pressure, turbulence rms velocity and integral length scale) correspond to conditions at the time of ignition in an automotive gasoline direct-injection reciprocating IC engine at low speed and light load. Both stoichiometric homogeneous reactants and non-homogeneous reactants with fuel-based equivalence ratios ranging from zero to four have been simulated. In the case of non-homogeneous reactants, a primary premixed flame (defined based on disappearance of the propane fuel) is followed by a secondary heat-release zone that is dominated by CO kinetics and turbulent mixing. Beyond a few flame thicknesses behind the primary flame, any remaining fuel has been broken down into carbon monoxide and hydrogen. Quantitative information relevant for modeling turbulent flame propagation through nonhomogeneous reactants has been extracted.

  11. Environmentally sound thermal energy extraction from coal and wastes using high temperature air combustion technology

    SciTech Connect

    Yoshikawa, Kunio

    1999-07-01

    High temperature air combustion is one of promising ways of burning relatively low BTU gas obtained from gasification of low grade coal or wastes. In this report, the author proposes a new power generation system coupled with high temperature air gasification of coal/wastes and high temperature air combustion of the syngas from coal/wastes. This system is realized by employing Multi-staged Enthalpy Extraction Technology (MEET). The basic idea of the MEET system is that coal or wastes are gasified with high temperature air of about 1,000 C, then the generated syngas is cooled in a heat recovery boiler to be cleaned-up in a gas cleanup system (desulfurization, desalinization and dust removal). Part of thermal energy contained in this cleaned-up syngas is used for high temperature air preheating, and the complete combustion of the fuel gas is done using also high temperature air for driving gas turbines or steam generation in a boiler.

  12. Analysis of spanwise temperature distribution in three types of air-cooled turbine blade

    NASA Technical Reports Server (NTRS)

    Livingood, John N B; Brown, W Byron

    1950-01-01

    Methods for computing spanwise blade-temperature distributions are derived for air-cooled hollow blades, air-cooled hollow blades with inserts, and air-cooled blades containing internal cooling fins. Individual and combined effects on spanwise blade-temperature distributions of cooling-air and radial heat conduction are determined. In general, the effects of radiation and radial heat conduction were found to be small and the omission of these variations permitted the construction of nondimensional charts for use in determining spanwise temperature distribution through air-cooled turbine blades. An approximate method for determining the allowable stress-limited blade-temperature distribution is included, with brief accounts of a method for determining the maximum allowable effective gas temperatures and the cooling-air requirements. Numerical examples that illustrate the use of the various temperature-distribution equations and of the nondimensional charts are also included.

  13. Direct numerical simulation of auto-ignition of a hydrogen vortex ring reacting with hot air

    SciTech Connect

    Doom, Jeff; Mahesh, Krishnan

    2009-04-15

    Direct numerical simulation (DNS) is used to study chemically reacting, laminar vortex rings. A novel, all-Mach number algorithm developed by Doom et al. [J. Doom, Y. Hou, K. Mahesh, J. Comput. Phys. 226 (2007) 1136-1151] is used. The chemical mechanism is a nine species, nineteen reaction mechanism for H{sub 2}/air combustion proposed by Mueller et al. [M.A. Mueller, T.J. Kim, R.A. Yetter, F.L. Dryer, Int. J. Chem. Kinet. 31 (1999) 113-125]. Diluted H{sub 2} at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratios, oxidizer temperature, Lewis number and stroke ratio (ratio of piston stroke length to diameter). Results show that auto-ignition occurs in fuel lean, high temperature regions with low scalar dissipation at a 'most reactive' mixture fraction, {zeta}{sub MR} (Mastorakos et al. [E. Mastorakos, T.A. Baritaud, T.J. Poinsot, Combust. Flame 109 (1997) 198-223]). Subsequent evolution of the flame is not predicted by {zeta}{sub MR}; a most reactive temperature T{sub MR} is defined and shown to predict both the initial auto-ignition as well as subsequent evolution. For stroke ratios less than the formation number, ignition in general occurs behind the vortex ring and propagates into the core. At higher oxidizer temperatures, ignition is almost instantaneous and occurs along the entire interface between fuel and oxidizer. For stroke ratios greater than the formation number, ignition initially occurs behind the leading vortex ring, then occurs along the length of the trailing column and propagates toward the ring. Lewis number is seen to affect both the initial ignition as well as subsequent flame evolution significantly. Non-uniform Lewis number simulations provide faster ignition and burnout time but a lower maximum temperature. The fuel rich reacting vortex ring provides the highest maximum temperature and the higher oxidizer temperature provides the fastest ignition time. The fuel lean reacting vortex ring has

  14. Temporal and spatial assessments of minimum air temperature using satellite surface temperature measurements in Massachusetts, USA

    PubMed Central

    Kloog, Itai; Chudnovsky, Alexandra; Koutrakis, Petros; Schwartz, Joel

    2015-01-01

    Although meteorological stations provide accurate air temperature observations, their spatial coverage is limited and thus often insufficient for epidemiological studies. Satellite data expand spatial coverage, enhancing our ability to estimate near surface air temperature (Ta). However, the derivation of Ta from surface temperature (Ts) measured by satellites is far from being straightforward. In this study, we present a novel approach that incorporates land use regression, meteorological variables and spatial smoothing to first calibrate between Ts and Ta on a daily basis and then predict Ta for days when satellite Ts data were not available. We applied mixed regression models with daily random slopes to calibrate Moderate Resolution Imaging Spectroradiometer (MODIS) Ts data with monitored Ta measurements for 2003. Then, we used a generalized additive mixed model with spatial smoothing to estimate Ta in days with missing Ts. Out-of-sample tenfold cross-validation was used to quantify the accuracy of our predictions. Our model performance was excellent for both days with available Ts and days without Ts observations (mean out-of-sample R2=0.946 and R2=0.941 respectively). Furthermore, based on the high quality predictions we investigated the spatial patterns of Ta within the study domain as they relate to urban vs. non-urban land uses. PMID:22721687

  15. Heat transfer analysis for high temperature preheated air combustion in furnace

    SciTech Connect

    Taniguchi, H.; Arai, N.; Kudo, K.; Aoki, K.

    1998-07-01

    The high temperature preheated air combustion system has been recently developed and techniques of heat transfer analysis pose important problems in its application to the industrial field. The three-dimensional simulation has to be introduced, therefore, for the above heat transfer analysis with combustion, fluid flow and heat transfer. Another effort may be introduced to reduce the computing time of heat transfer analysis by means of some simplification in software of chemical simulation, etc. If one has introduced the application of the high temperature preheated air combustion technique in natural gas firing, the non-gray radiation should be applied to each radiant gas of CO{sub 2}, H{sub 2}O, CO or CH{sub 4}, in this analysis. Finally, the authors would like to refer the inverse computation of radiation heat transfer in furnace which has been proposed by one of the authors and another researcher in the United States. If one tries to estimate the performance of an industrial furnace, the heat flux on heating material is the most important factor which has been fixed as input data of computation. Therefore, the heat transfer analysis may be sometimes reversed by fixed data of heat flux and proceeded by trial and error method, in order to obtain the initial condition of heat source and furnace facilities.

  16. Simulation of rice plant temperatures using the UC Davis Advanced Canopy-Atmosphere-Soil Algorithm (ACASA)

    NASA Astrophysics Data System (ADS)

    Maruyama, A.; Pyles, D.; Paw U, K.

    2009-12-01

    The thermal environment in the plant canopy affects plants’ growth processes such as flowering and ripening. High temperatures often cause grain sterility and poor filling in serial crops, and reduce their production in tropical and temperate regions. With global warming predicted, these effects have become a major concern worldwide. In this study, we observed the plant body temperature profiles for the rice canopy and simulate them using a higher-order closure micrometeorological model to understand the relationship between plant temperatures and atmospheric condition. Experiments were conducted in rice paddy during 2007-summer season under warm temperate climate in Japan. Leaf temperatures at three different height (0.3, 0.5, 0.7m) and panicle temperatures at 0.9m were measured using fine-thermocouples. The UC Davis Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) was used to calculate plant body temperature profiles in the canopy. ACASA is based on the radiation transfer, higher-order closure of turbulent equations for mass and heat exchange, and detailed plant physiological parameterization for the canopy-atmosphere-soil system. Water temperature was almost constant of 21-23 C throughout the summer because of continuous irrigation. Therefore, larger difference between air temperature at 2 m and water temperature was found on daytime. Observed leaf/panicle temperature was lower near the water surface and higher on upper layer in the canopy. Difference of temperatures between 0.3 m and 0.9 m was around 3-4 C for daytime, and around 1-2 C for nighttime. Calculated result of ACASA recreated these trends of plant temperature profile sufficiently. However, the relationship between plant and air temperature in the canopy was a little different from observed, i.e. observed leaf/panicle temperature were almost the same as air temperature, in contrast the simulated air temperature was 0.5-1.5 C higher than plant temperatures for the both of daytime and night time

  17. An improved model for soil surface temperature from air temperature in permafrost regions of Qinghai-Xizang (Tibet) Plateau of China

    NASA Astrophysics Data System (ADS)

    Hu, Guojie; Wu, Xiaodong; Zhao, Lin; Li, Ren; Wu, Tonghua; Xie, Changwei; Pang, Qiangqiang; Cheng, Guodong

    2016-06-01

    Soil temperature plays a key role in hydro-thermal processes in environments and is a critical variable linking surface structure to soil processes. There is a need for more accurate temperature simulation models, particularly in Qinghai-Xizang (Tibet) Plateau (QXP). In this study, a model was developed for the simulation of hourly soil surface temperatures with air temperatures. The model incorporated the thermal properties of the soil, vegetation cover, solar radiation, and water flux density and utilized field data collected from Qinghai-Xizang (Tibet) Plateau (QXP). The model was used to simulate the thermal regime at soil depths of 5 cm, 10 cm and 20 cm and results were compared with those from previous models and with experimental measurements of ground temperature at two different locations. The analysis showed that the newly developed model provided better estimates of observed field temperatures, with an average mean absolute error (MAE), root mean square error (RMSE), and the normalized standard error (NSEE) of 1.17 °C, 1.30 °C and 13.84 %, 0.41 °C, 0.49 °C and 5.45 %, 0.13 °C, 0.18 °C and 2.23 % at 5 cm, 10 cm and 20 cm depths, respectively. These findings provide a useful reference for simulating soil temperature and may be incorporated into other ecosystem models requiring soil temperature as an input variable for modeling permafrost changes under global warming.

  18. A High-Fidelity Batch Simulation Environment for Integrated Batch and Piloted Air Combat Simulation Analysis

    NASA Technical Reports Server (NTRS)

    Goodrich, Kenneth H.; McManus, John W.; Chappell, Alan R.

    1992-01-01

    A batch air combat simulation environment known as the Tactical Maneuvering Simulator (TMS) is presented. The TMS serves as a tool for developing and evaluating tactical maneuvering logics. The environment can also be used to evaluate the tactical implications of perturbations to aircraft performance or supporting systems. The TMS is capable of simulating air combat between any number of engagement participants, with practical limits imposed by computer memory and processing power. Aircraft are modeled using equations of motion, control laws, aerodynamics and propulsive characteristics equivalent to those used in high-fidelity piloted simulation. Databases representative of a modern high-performance aircraft with and without thrust-vectoring capability are included. To simplify the task of developing and implementing maneuvering logics in the TMS, an outer-loop control system known as the Tactical Autopilot (TA) is implemented in the aircraft simulation model. The TA converts guidance commands issued by computerized maneuvering logics in the form of desired angle-of-attack and wind axis-bank angle into inputs to the inner-loop control augmentation system of the aircraft. This report describes the capabilities and operation of the TMS.

  19. Extensive air shower simulations with the CORSIKA program

    SciTech Connect

    Capdevielee, J.N.; Gabriel, P.; Gils, H.J.; Grieder, P.; Heck, D.; Knapp, J.; Mayer, H.J.; Oehlschlaeger, J.; Rebel, H.; Schatz, G.; Thouw, T. )

    1993-06-15

    CORSIKA is a detailed Monte Carlo program to study the development of extensive air showers in the atmosphere initiated by photons, protons, or nuclei of energies up to 10[sup 17] eV. Wherever possible experimentally accessible data have been used to model the high energy interactions of primary and secondary particles with the nuclei of the atmosphere. The CORSIKA code is based essentially on the Dual Parton Model to describe the hadronic interactions at high energies, the isobar model for hadronic reactions at low energies, and EGS4 for a detailed simulation of the electromagnetic part. The nucleus-nucleus interaction model follows the considerations of Klar and Huefner. Heuristic nucleus fragment models are implemented. Diffractive and charge exchange reactions are possible. Photoproduction of muon pairs and hadrons has been introduced into the electromagnetic part. The gross features of the program are presented and some results are given.

  20. DEVELOPMENT OF MESOSCALE AIR QUALITY SIMULATION MODELS. VOLUME 6. USER'S GUIDE TO MESOPAC (MESOSCALE METEOROLOGY PACKAGE)

    EPA Science Inventory

    MESOPAC is a mesoscale meteorological preprocessor program; it is designed to provide meteorological data to regional-scale air quality simulation models. Radiosonde data routinely available from National Weather Service (NWS) radiosonde ('upper air') and surface stations are use...

  1. 40 CFR 86.162-03 - Approval of alternative air conditioning test simulations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... conditioning test simulations. 86.162-03 Section 86.162-03 Protection of Environment ENVIRONMENTAL PROTECTION... alternative air conditioning test simulations. (a) Upon petition from a manufacturer or upon the Agency's own initiative, the Administrator will approve a simulation of the environmental cell for air conditioning...

  2. 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.

  3. User's manual for steady-state computer simulation for air-to-air heat pumps with selected examples

    SciTech Connect

    Not Available

    1982-06-30

    A steady-state computer simulation model has been developed for conventional, vapor compression cycle, electrically driven air-to-air heat pumps. Comparison between the heat pump simulation model predictions and available data from three heat pump experiments indicate that the predictions generally are within accepted tolerances. A sensitivity analysis was made to assess the effect of possible variations in some of the input parameters on the system's thermal performance. The computer simulation model is briefly described for heating and cooling modes, and simulation model input data and output are given. (LEW)

  4. Numerical Simulation of Hydrogen Air Supersonic Coaxial Jet

    NASA Astrophysics Data System (ADS)

    Dharavath, Malsur; Manna, Pulinbehari; Chakraborty, Debasis

    2016-06-01

    In the present study, the turbulent structure of coaxial supersonic H2-air jet is explored numerically by solving three dimensional RANS equations along with two equation k-ɛ turbulence model. Grid independence of the solution is demonstrated by estimating the error distribution using Grid Convergence Index. Distributions of flow parameters in different planes are analyzed to explain the mixing and combustion characteristics of high speed coaxial jets. The flow field is seen mostly diffusive in nature and hydrogen diffusion is confined to core region of the jet. Both single step laminar finite rate chemistry and turbulent reacting calculation employing EDM combustion model are performed to find the effect of turbulence-chemistry interaction in the flow field. Laminar reaction predicts higher H2 mol fraction compared to turbulent reaction because of lower reaction rate caused by turbulence chemistry interaction. Profiles of major species and temperature match well with experimental data at different axial locations; although, the computed profiles show a narrower shape in the far field region. These results demonstrate that standard two equation class turbulence model with single step kinetics based turbulence chemistry interaction can describe H2-air reaction adequately in high speed flows.

  5. Modelling and simulation of wood chip combustion in a hot air generator system.

    PubMed

    Rajika, J K A T; Narayana, Mahinsasa

    2016-01-01

    This study focuses on modelling and simulation of horizontal moving bed/grate wood chip combustor. A standalone finite volume based 2-D steady state Euler-Euler Computational Fluid Dynamics (CFD) model was developed for packed bed combustion. Packed bed combustion of a medium scale biomass combustor, which was retrofitted from wood log to wood chip feeding for Tea drying in Sri Lanka, was evaluated by a CFD simulation study. The model was validated by the experimental results of an industrial biomass combustor for a hot air generation system in tea industry. Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool. Height of the packed bed is about 20 cm and biomass particles are assumed to be spherical shape with constant surface area to volume ratio. Temperature measurements of the combustor are well agreed with simulation results while gas phase compositions have discrepancies. Combustion efficiency of the validated hot air generator is around 52.2 %. PMID:27512625

  6. Experimental Heat Transfer and Bulk Air Temperature Measurements for a Multipass Internal Cooling Model with Ribs and Bleed

    NASA Technical Reports Server (NTRS)

    Thurman, Douglas; Poinsatte, Philip

    2001-01-01

    An experimental study was made to obtain heat transfer and air temperature data for a simple three-leg serpentine test section that simulates a turbine blade internal cooling passage with trip strips and bleed holes. The objectives were to investigate the interaction of ribs and various bleed conditions on internal cooling and to gain a better understanding of bulk air temperature in an internal passage. Steady-state heat transfer measurements were obtained using a transient technique with thermochromic liquid crystals. Trip strips were attached to one wall of the test section and were located either between or near the bleed holes. The bleed holes, used for film cooling, were metered to simulate the effect of external pressure on the turbine blade. Heat transfer enhancement was found to be greater for ribs near bleed holes compared to ribs between holes, and both configurations were affected slightly by bleed rates upstream. Air temperature measurements were taken at discrete locations along one leg of the model. Average bulk air temperatures were found to remain fairly constant along one leg of the model.

  7. Experimental Heat Transfer and Bulk Air Temperature Measurements for a Multipass Internal Cooling Model with Ribs and Bleed

    NASA Technical Reports Server (NTRS)

    Thurman, Douglas; Poinsatte, Philip

    2000-01-01

    An experimental study was made to obtain heat transfer and air temperature data for a simple 3-leg serpentine test section that simulates a turbine blade internal cooling passage with trip strips and bleed holes. The objectives were to investigate the interaction of ribs and various bleed conditions on internal cooling and to gain a better understanding of bulk air temperature in an internal passage. Steady state heat transfer measurements were obtained using a transient technique with thermochromic liquid crystals. Trip strips were attached to one wall of the test section and were located either between or near the bleed holes. The bleed holes, used for film cooling, were metered to simulate the effect of external pressure on the turbine blade. Heat transfer enhancement was found to be greater for ribs near bleed holes compared to ribs between holes, and both configurations were affected slightly by bleed rates upstream. Air temperature measurements were taken at discreet locations along one leg of the model. Average bulk air temperatures were found to remain fairly constant along one leg of the model.

  8. Short-term effects of air temperature on plasma metabolite concentrations in patients undergoing cardiac cattheterization.

    EPA Science Inventory

    BACKGROUND: Epidemiological studies have shown associations between air temperature and cardiovascular health outcomes. Metabolic dysregulation might also play a role in the development of cardiovascular disease.OBJECTIVES: To investigate short-term temperature effects on metabol...

  9. Startup of air-cooled condensers and dry cooling towers at low temperatures of the cooling air

    NASA Astrophysics Data System (ADS)

    Milman, O. O.; Ptakhin, A. V.; Kondratev, A. V.; Shifrin, B. A.; Yankov, G. G.

    2016-05-01

    The problems of startup and performance of air-cooled condensers (ACC) and dry cooling towers (DCT) at low cooling air temperatures are considered. Effects of the startup of the ACC at sub-zero temperatures are described. Different options of the ACC heating up are analyzed, and examples of existing technologies are presented (electric heating, heating up with hot air or steam, and internal and external heating). The use of additional heat exchanging sections, steam tracers, in the DCT design is described. The need for high power in cases of electric heating and heating up with hot air is noted. An experimental stand for research and testing of the ACC startup at low temperatures is described. The design of the three-pass ACC unit is given, and its advantages over classical single-pass design at low temperatures are listed. The formation of ice plugs inside the heat exchanging tubes during the start-up of ACC and DCT at low cooling air temperatures is analyzed. Experimental data on the effect of the steam flow rate, steam nozzle distance from the heat-exchange surface, and their orientation in space on the metal temperature were collected, and test results are analyzed. It is noted that the surface temperature at the end of the heat up is almost independent from its initial temperature. Recommendations for the safe start-up of ACCs and DCTs are given. The heating flow necessary to sufficiently heat up heat-exchange surfaces of ACCs and DCTs for the safe startup is estimated. The technology and the process of the heat up of the ACC with the heating steam external supply are described by the example of the startup of the full-scale section of the ACC at sub-zero temperatures of the cooling air, and the advantages of the proposed start-up technology are confirmed.

  10. One-Component Pressure-Temperature Phase Diagrams in the Presence of Air

    ERIC Educational Resources Information Center

    Andrade-Gamboa, Julio; Martire, Daniel O.; Donati, Edgardo R.

    2010-01-01

    One-component phase diagrams are good approximations to predict pressure-temperature ("P-T") behavior of a substance in the presence of air, provided air pressure is not much higher than the vapor pressure. However, at any air pressure, and from the conceptual point of view, the use of a traditional "P-T" phase diagram is not strictly correct. In…

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Ground surface temperature simulation for different land covers

    NASA Astrophysics Data System (ADS)

    Herb, William R.; Janke, Ben; Mohseni, Omid; Stefan, Heinz G.

    2008-07-01

    SummaryA model for predicting temperature time series for dry and wet land surfaces is described, as part of a larger project to assess the impact of urban development on the temperature of surface runoff and coldwater streams. Surface heat transfer processes on impervious and pervious land surfaces were investigated for both dry and wet weather periods. The surface heat transfer equations were combined with a numerical approximation of the 1-D unsteady heat diffusion equation to calculate pavement and soil temperature profiles to a depth of 10 m. Equations to predict the magnitude of the radiative, convective, conductive and evaporative heat fluxes at a dry or wet surface, using standard climate data as input, were developed. A model for the effect of plant canopies on surface heat transfer was included for vegetated land surfaces. Given suitable climate data, the model can simulate the land surface and sub-surface temperatures continuously throughout a six month time period or for a single rainfall event. Land surface temperatures have been successfully simulated for pavements, bare soil, short and tall grass, a forest, and two agricultural crops (corn and soybeans). The simulations were run for three different locations in US, and different years as imposed by the availability of measured soil temperature and climate data. To clarify the effect of land use on surface temperatures, the calibrated coefficients for each land use and the same soil coefficients were used to simulate surface temperatures for a six year climate data set from Albertville, MN. Asphalt and concrete give the highest surface temperatures, as expected, while vegetated surfaces gave the lowest. Bare soil gives surface temperatures that lie between those for pavements and plant-covered surfaces. The soil temperature model predicts hourly surface temperatures of bare soil and pavement with root-mean-square errors (RMSEs) of 1-2 °C, and hourly surface temperatures of vegetation-covered surfaces

  17. The impact of heterogeneous surface temperatures on the 2-m air temperature over the Arctic Ocean in spring

    NASA Astrophysics Data System (ADS)

    Tetzlaff, A.; Kaleschke, L.; Lüpkes, C.; Ament, F.; Vihma, T.

    2012-07-01

    The influence of spatial surface temperature changes over the Arctic Ocean on the 2-m air temperature variability is estimated using backward trajectories based on ERA-Interim and the JRA25 wind fields. They are initiated at Alert, Barrow and at the Tara drifting station. Three different methods are used. The first one compares mean ice surface temperatures along the trajectories to the observed 2-m air temperatures at the stations. The second one correlates the observed temperatures to air temperatures obtained using a simple Lagrangian box model which only includes the effect of sensible heat fluxes. For the third method, mean sensible heat fluxes from the model are correlated with the difference of the air temperatures at the model starting point and the observed temperatures at the stations. The calculations are based on MODIS ice surface temperatures and four different sets of ice concentration derived from SSM/I and AMSR-E data. Under nearly cloud free conditions, up to 90% of the 2-m air temperature variance can be explained for Alert, and 60% for Barrow using these methods. The differences are attributed to the different ice conditions, which are characterized by high ice concentration around Alert and lower ice concentration near Barrow. These results are robust for the different sets of reanalyses and ice concentration data. Near-surface winds of both reanalyses show a large inconsistency in the Central Arctic, which leads to a large difference in the correlations between modeled and observed 2-m air temperatures at Tara. Explained variances amount to 70% using JRA and only 45% using ERA. The results also suggest that near-surface temperatures at a given site are influenced by the variability of surface temperatures in a domain of about 150 to 350 km radius around the site.

  18. A simplified physically-based model to calculate surface water temperature of lakes from air temperature in climate change scenarios

    NASA Astrophysics Data System (ADS)

    Piccolroaz, S.; Toffolon, M.

    2012-12-01

    Modifications of water temperature are crucial for the ecology of lakes, but long-term analyses are not usually able to provide reliable estimations. This is particularly true for climate change studies based on Global Circulation Models, whose mesh size is normally too coarse for explicitly including even some of the biggest lakes on Earth. On the other hand, modeled predictions of air temperature changes are more reliable, and long-term, high-resolution air temperature observational datasets are more available than water temperature measurements. For these reasons, air temperature series are often used to obtain some information about the surface temperature of water bodies. In order to do that, it is common to exploit regression models, but they are questionable especially when it is necessary to extrapolate current trends beyond maximum (or minimum) measured temperatures. Moreover, water temperature is influenced by a variety of processes of heat exchange across the lake surface and by the thermal inertia of the water mass, which also causes an annual hysteresis cycle between air and water temperatures that is hard to consider in regressions. In this work we propose a simplified, physically-based model for the estimation of the epilimnetic temperature in lakes. Starting from the zero-dimensional heat budget, we derive a simplified first-order differential equation for water temperature, primarily forced by a seasonally varying external term (mainly related to solar radiation) and an exchange term explicitly depending on the difference between air and water temperatures. Assuming annual sinusoidal cycles of the main heat flux components at the atmosphere-lake interface, eight parameters (some of them can be disregarded, though) are identified, which can be calibrated if two temporal series of air and water temperature are available. We note that such a calibration is supported by the physical interpretation of the parameters, which provide good initial

  19. Modeling greenup date of dominant grass species in the Inner Mongolian Grassland using air temperature and precipitation data.

    PubMed

    Chen, Xiaoqiu; Li, Jing; Xu, Lin; Liu, Li; Ding, Deng

    2014-05-01

    This work was undertaken to examine the combined effect of air temperature and precipitation during late winter and early spring on modeling greenup date of grass species in the Inner Mongolian Grassland. We used the traditional thermal time model and developed two revised thermal time models coupling air temperature and precipitation to simulate greenup date of three dominant grass species at six stations from 1983 to 2009. Results show that climatic controls on greenup date of grass species were location-specific. The revised thermal time models coupling air temperature and precipitation show higher simulation parsimony and efficiency than the traditional thermal time model for five of 11 data sets at Bayartuhushuo, Xilinhot and Xianghuangqi, whereas the traditional thermal time model indicates higher simulation parsimony and efficiency than the revised thermal time models coupling air temperature and precipitation for the other six data sets at E'ergunayouqi, Ewenkeqi and Chaharyouyihouqi. The mean root mean square error of the 11 models is 4.9 days. Moreover, the influence of late winter and early spring precipitation on greenup date seems to be stronger at stations with scarce precipitation than at stations with relatively abundant precipitation. From the mechanism perspectives, accumulated late winter and early spring precipitation may play a more important role as the precondition of forcing temperature than as the supplementary condition of forcing temperature in triggering greenup. Our findings suggest that predicting responses of grass phenology to global climate change should consider both thermal and moisture scenarios in some semiarid and arid areas. PMID:24065573

  20. Dynamical Simulation of Cloudy Boundary Layer Flow during Cold Air Outbreaks.

    NASA Astrophysics Data System (ADS)

    Yuen, Chiu-Wai

    situation observed over The East China Sea, downwind variation of dynamical and thermodynamical boundary layer properties and cloud distribution are well reproduced. The steep sea surface temperature gradient produces strong boundary layer baroclinity and a strong divergent boundary layer flow. The simulated large cross-isobar angle in association with intense cold air advection and vigorous momentum mixing is in favorable agreement with both observation and theory.

  1. Prototypical experiments relating to air oxidation of Zircaloy-4 at high temperatures

    NASA Astrophysics Data System (ADS)

    Steinbrück, Martin

    2009-08-01

    The mechanism of the reaction between Zircaloy-4 and air at temperatures from 800 to 1500 °C was studied. Air attack under prototypical conditions with air ingress during a hypothetic severe nuclear reactor accident was investigated. Oxidation in air and in air and nitrogen-containing atmospheres leads to a major degradation of the cladding material. The main mechanism is the formation of zirconium nitride and its re-oxidation. Pre-oxidation in steam prevents air attack as long as the oxide scale is intact. Under steam/oxygen starvation conditions, the oxide scale is reduced and significant external nitride formation takes place. When modeling air ingress in severe accident computer codes, parabolic correlations for oxidation in air may be applied only for high temperatures (>1400 °C) and for pre-oxidized cladding (⩾1100 °C). Under all other conditions, faster, rather linear reaction kinetics should be applied.

  2. Evaluation of the GEM-AQ simulations for the Air Quality Model Evaluation International Initiative (AQMEII)

    NASA Astrophysics Data System (ADS)

    Lobocki, Lech; Gawuc, Lech; Jefimow, Maciej; Kaminski, Jacek; Porebska, Magdalena; Struzewska, Joanna; Zdunek, Malgorzata

    2013-04-01

    A multiscale, on-line meteorological and air quality model GEM-AQ was used to simulate ozone and particulate matter over the European continent in 2006, as a part of the Air Quality Model Evaluation International Initiative (AQMEII). In contrast to the majority of models participating in the Phase I of AQMEII, the GEM-AQ configuration employed here utilized neither external meteorological fields nor lateral boundary conditions, owing to the global-extent and variable grid resolution of the model setup. We will present evaluation results for global model performance statistics calculated for the entire year and more detailed performance analysis of pollution episodes. Evaluation of meteorological parameters includes comparisons of model-predicted wind, temperature and cloudiness with hourly observations at surface weather stations, daily maxima, and comparison with upper-air soundings at selected sites. Frequency distribution of principal boundary layer parameters and its spatial structure will be presented. Air quality predictions are assessed in terms of ground-level daily mean ozone concentrations and its daily peak values, vertical structure as inferred from ozone soundings, and particulate matter daily mean concentrations at the surface.

  3. SOSIE: A pragmatic approach to the simulation of Broad Air Defense applied to the theater level

    NASA Astrophysics Data System (ADS)

    Tanter, A.; Deas, M.

    1995-01-01

    The SOSIE concept rests on an approach consisting of using existing simulation models of various systems and subsystems and automatically integrating them with minimum modifications within a center of simulation. The defense simulation against ballistic missiles on the theater level calls upon three levels of simulation: DIAMS; TACSIT, and SPOOK. DIAMS presents a fine level system simulation of weapon ground-to-air average carry, TACSIT presents a level of site defense (base air for example), and SPOOK deals with the theater level itself. SOSIE enables users to use the same detailed simulators, developed by an originator of weapon systems or information and communications, without having to know in detail the models of the simulation. Envisioned in the future is the integration of other models of simulations relating to the air-to-air combat, in particular, the networks of command, controls and communications.

  4. MULTISCALE AIR QUALITY SIMULATION PLATFORM (MAQSIP): INITIAL APPLICATIONS AND PERFORMANCE FOR TROPOSPHERIC OZONE AND PARTICULATE MATTER

    EPA Science Inventory

    This manuscript provides an overview of the formulation, process considerations, and performance for simulating tropospheric ozone and particulate matter distributions of the Multiscale Air Quality Simulation Platform (MAQSIP). MAQSIP is a comprehensive atmospheric chemistry/tran...

  5. Predicting seed cotton moisture content from changes in drying air temperature - second year

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A mathematical model was used to predict seed cotton moisture content in the overhead section of a cotton gin. The model took into account the temperature, mass flow, and specific heat of both the air and seed cotton. Air temperatures and mass flows were measured for a second year at a commercial g...

  6. Correction of Temperatures of Air-Cooled Engine Cylinders for Variation in Engine and Cooling Conditions

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Pinkel, Benjamin; Ellerbrock, Herman H , Jr

    1939-01-01

    Factors are obtained from semiempirical equations for correcting engine-cylinder temperatures for variation in important engine and cooling conditions. The variation of engine temperatures with atmospheric temperature is treated in detail, and correction factors are obtained for various flight and test conditions, such as climb at constant indicated air speed, level flight, ground running, take-off, constant speed of cooling air, and constant mass flow of cooling air. Seven conventional air-cooled engine cylinders enclosed in jackets and cooled by a blower were tested to determine the effect of cooling-air temperature and carburetor-air temperature on cylinder temperatures. The cooling air temperature was varied from approximately 80 degrees F. to 230 degrees F. and the carburetor-air temperature from approximately 40 degrees F. to 160 degrees F. Tests were made over a large range of engine speeds, brake mean effective pressures, and pressure drops across the cylinder. The correction factors obtained experimentally are compared with those obtained from the semiempirical equations and a fair agreement is noted.

  7. Effects of Outside Air Temperature on Movement of Phosphine Gas in Concrete Elevator Bins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies that measured the movement and concentration of phosphine gas in upright concrete bins over time indicated that fumigant movement was dictated by air currents, which in turn, were a function of the difference between the average grain temperature and the average outside air temperature durin...

  8. Velocity and temperature field characteristics of water and air during natural convection heating in cans.

    PubMed

    Erdogdu, Ferruh; Tutar, Mustafa

    2011-01-01

    Presence of headspace during canning is required since an adequate amount allows forming vacuum during the process. Sealing technology may not totally eliminate all entrapped gases, and headspace might affect heat transfer. Not much attention has been given to solve this problem in computational studies, and cans, for example, were mostly assumed to be fully filled with product. Therefore, the objective of this study was to determine velocity and temperature evolution of water and air in cans during heating to evaluate the relevance of headspace in the transport mechanism. For this purpose, canned water samples with a certain headspace were used, and required governing continuity, energy, and momentum equations were solved using a finite volume approach coupled with a volume of fluid element model. Simulation results correlated well with experimental results validating faster heating effects of headspace rather than insulation effects as reported in the literature. The organized velocity motions along the air-water interface were also shown. Practical Application: Canning is a universal and economic method for processing of food products, and presence of adequate headspace is required to form vacuum during sealing of the cans. Since sealing technology may not totally eliminate the entrapped gases, mainly air, headspace might affect heating rates in cans. This study demonstrated the increased heating rates in the presence of headspace in contrast with some studies in the literature. By applying the effect of headspace, required processing time for thermally processed foods can be reduced leading to more rapid processes and lower energy consumptions. PMID:21535663

  9. Comparison of regional air dispersion simulation and ambient air monitoring data for the soil fumigant 1,3-dichloropropene.

    PubMed

    van Wesenbeeck, I J; Cryer, S A; de Cirugeda Helle, O; Li, C; Driver, J H

    2016-11-01

    SOFEA v2.0 is an air dispersion modeling tool used to predict acute and chronic pesticide concentrations in air for large air sheds resulting from agronomic practices. A 1,3-dichloropropene (1,3-D) air monitoring study in high use townships in Merced County, CA, logged 3-day average air concentrations at nine locations over a 14.5month period. SOFEA, using weather data measured at the site, and using a historical CDPR regulatory assumption of a constant 320m mixing height, predicted the general pattern and correct order of magnitude for 1,3-D air concentrations as a function of time, but failed to estimate the highest observed 1,3-D concentrations of the monitoring study. A time series and statistical comparison of the measured and modeled data indicated that the model underestimated 1,3-D concentrations during calm periods (wind speed <1m/s), such that the annual average concentration was under predicted by approximately 4.7-fold, and the variability was not representative of the measured data. Calm periods are associated with low mixing heights (MHs) and are more prevalent in the Central Valley of CA during the winter months, and thus the assumption of a constant 320m mixing height is not appropriate. An algorithm was developed to calculate the MH using the air temperature in the weather file when the wind speed was <1m/s. When the model was run using the revised MHs, the average of the modeled 1,3-D concentration Probability Distribution Function (PDF) was within 5% of the measured PDF, and the variability in modeled concentrations more closely matched the measured dataset. Use of the PCRAMMET processed weather data from the site (including PCRAMMET MH) resulted in the global annual average concentration within 2-fold of measured data. Receptor density was also found to have an effect on the modeled 1,3-D concentration PDF, and a 50×50 receptor grid in the nine township domain captured the measured 1,3-D concentration distribution much better than a 3×3

  10. Cenozoic ice volume and temperature simulations with a 1-D ice-sheet model

    NASA Astrophysics Data System (ADS)

    de Boer, B.; van de Wal, R. S. W.; Bintanja, R.; Lourens, L. J.; Tuenter, E.

    2009-04-01

    Ice volume and temperature for the past 35 Million years is investigated with a 1-D ice-sheet model, simulating ice-sheets on both hemispheres. The simulations include two continental Northern Hemisphere (NH) ice-sheets representative for glaciation on the two major continents, i.e. Eurasia (EAZ) and North America (NAM). Antarctic glaciation is simulated with two separate ice-sheets, respectively for West and East Antarctica. The surface air temperature is reconstructed with an inventive inverse procedure, forced with benthic δ18O data. The procedure linearly relates the temperature to the difference between the modelled and observed marine δ18O 100 years later. The derived temperature, representative for the NH, is used to run the ice-sheet model over 100 years, to obtain a mutually consistent record of marine δ18O, sea level and temperature for the last 35 Ma of the Cenozoic. For Northern Hemispheric glaciations results are good compared to similar simulations performed with a much more comprehensive 3-D ice-sheet model. On average, differences are only 1.9 ˚ C for temperature and 6.1 m for sea level. Results with ice-sheets on both hemispheres are very similar. Most notably, the reconstructed ice volume as function of temperature shows a transition from climate dominated by Antarctic ice volume variation towards NH ice-sheets controlled climate. The transition period falls within the range of interglacials (about -2 to +8 ˚ C with respect to present day) and is thus characterized by lower ice volume changes per ˚ C. The relationship between temperature, sea level and δ18O input is tested with an equilibrium experiment, which results in a linear and symmetric relationship for both temperature and total sea level, providing limited evidence for hysteresis, though transient behaviour is still important. Furthermore results show a rather good comparison with other simulations of Antarctic ice volume and observed sea level and deep-sea temperature.

  11. Temperature measurement error simulation of the pure rotational Raman lidar

    NASA Astrophysics Data System (ADS)

    Jia, Jingyu; Huang, Yong; Wang, Zhirui; Yi, Fan; Shen, Jianglin; Jia, Xiaoxing; Chen, Huabin; Yang, Chuan; Zhang, Mingyang

    2015-11-01

    Temperature represents the atmospheric thermodynamic state. Measure the atmospheric temperature accurately and precisely is very important to understand the physics of the atmospheric process. Lidar has some advantages in the atmospheric temperature measurement. Based on the lidar equation and the theory of pure rotational Raman (PRR), we've simulated the temperature measurement errors of the double-grating-polychromator (DGP) based PRR lidar. First of all, without considering the attenuation terms of the atmospheric transmittance and the range in the lidar equation, we've simulated the temperature measurement errors which are influenced by the beam splitting system parameters, such as the center wavelength, the receiving bandwidth and the atmospheric temperature. We analyzed three types of the temperature measurement errors in theory. We've proposed several design methods for the beam splitting system to reduce the temperature measurement errors. Secondly, we simulated the temperature measurement error profiles by the lidar equation. As the lidar power-aperture product is determined, the main target of our lidar system is to reduce the statistical and the leakage errors.

  12. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    NASA Astrophysics Data System (ADS)

    Kang, H.-J.; Yoo, J.-M.; Jeong, M.-J.; Won, Y.-I.

    2015-10-01

    Uncertainties in the satellite-derived surface skin temperature (SST) data in the polar oceans during two periods (16-24 April and 15-23 September) 2003-2014 were investigated and the three data sets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST), the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU), and AIRS only. The AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically warmer up to 1.65 K at the sea ice boundary and colder down to -2.04 K in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992-0.999) method was greater than that of the MODIS IST to the AIRS/AMSU (0.968-0.994). The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of -0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a less accurate GCM forecast over the seasonally varying frozen oceans than the microwave data. The three data sets (MODIS, AIRS/AMSU and AIRS only) showed significant warming rates (2.3 ± 1.7 ~ 2.8 ± 1.9 K decade-1) in the northern high regions (70-80° N) as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  13. Uncertainties of satellite-derived surface skin temperatures in the polar oceans: MODIS, AIRS/AMSU, and AIRS only

    NASA Astrophysics Data System (ADS)

    Kang, H.-J.; Yoo, J.-M.; Jeong, M.-J.; Won, Y.-I.

    2015-05-01

    Uncertainties in the satellite-derived Surface Skin Temperature (SST) data in the polar oceans during two periods (16-24 April and 15-23 September) of 2003-2014 were investigated and the three datasets were intercompared as follows: MODerate Resolution Imaging Spectroradiometer Ice Surface Temperature (MODIS IST), the SST of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit-A (AIRS/AMSU), and AIRS only. AIRS only algorithm was developed in preparation for the degradation of the AMSU-A. MODIS IST was systematically up to 1.65 K warmer at the sea ice boundary and up to 2.04 K colder in the polar sea ice regions of both the Arctic and Antarctic than that of the AIRS/AMSU. This difference in the results could have been caused by the surface classification method. The spatial correlation coefficient of the AIRS only to the AIRS/AMSU (0.992-0.999) method was greater than that of the MODIS IST to the AIRS/AMSU (0.968-0.994). The SST of the AIRS only compared to that of the AIRS/AMSU had a bias of 0.168 K with a RMSE of 0.590 K over the Northern Hemisphere high latitudes and a bias of -0.109 K with a RMSE of 0.852 K over the Southern Hemisphere high latitudes. There was a systematic disagreement between the AIRS retrievals at the boundary of the sea ice, because the AIRS only algorithm utilized a~less accurate GCM forecast over the seasonally-varying frozen oceans than the microwave data. The three datasets (MODIS, AIRS/AMSU and AIRS only) showed significant warming rates (2.3 ± 1.7 ~2.8 ± 1.9 K decade-1) in the northern high latitude regions (70-80° N) as expected from the ice-albedo feedback. The systematic temperature disagreement associated with surface type classification had an impact on the resulting temperature trends.

  14. 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.

  15. Photoionization capable, extreme and vacuum ultraviolet emission in developing low temperature plasmas in air

    NASA Astrophysics Data System (ADS)

    Stephens, J.; Fierro, A.; Beeson, S.; Laity, G.; Trienekens, D.; Joshi, R. P.; Dickens, J.; Neuber, A.

    2016-04-01

    Experimental observation of photoionization capable extreme ultraviolet and vacuum ultraviolet emission from nanosecond timescale, developing low temperature plasmas (i.e. streamer discharges) in atmospheric air is presented. Applying short high voltage pulses enabled the observation of the onset of plasma formation exclusively by removing the external excitation before spark development was achieved. Contrary to the common assumption that radiative transitions from the b{{}1}{{\\Pi}u} (Birge-Hopfield I) and b{{}\\prime 1}Σu+ (Birge-Hopfield II) singlet states of N2 are the primary contributors to photoionization events, these results indicate that radiative transitions from the c{{4\\prime}1}Σu+ (Carroll-Yoshino) singlet state of N2 are dominant in developing low temperature plasmas in air. In addition to c{}4\\prime transitions, photoionization capable transitions from atomic and singly ionized atomic oxygen were also observed. The inclusion of c{{4\\prime}1}Σu+ transitions into a statistical photoionization model coupled with a fluid model enabled streamer growth in the simulation of positive streamers.

  16. Extending temperature sum models to simulate onset of birch flowering on the regional scale

    NASA Astrophysics Data System (ADS)

    Klein, Christian; Biernath, Christian; Priesack, Eckart

    2015-04-01

    For human health issues a reliable forecast of the onset of flowering of different plants which produce allergenic pollen is important. Yet, there are numerous phenological models available with different degrees of model complexity. All models consider the effect of the air temperatures on plant development; but only few models also include other environmental factors and/or plant internal water and nutrient status. However, the more complex models often use empirical relations without physiological meaning and are often tested against small datasets derived from a limited amount of sites. Most models which are used to simulate plant phenology are based on the temporal integration of temperatures above a defined base temperature. A critical temperature sum then defines the onset of a new phenological stage. The use of models that base on temperatures only, is efficient as temperatures are the most frequently documented and available weather component on global, regional and local scales. These models score by their robustness over a wide range of environmental conditions. However, the simulations sometimes fail by more than 20 days compared to measurements, and thus are not adequate for their use in pollen forecast. We tested the ability of temperature sum models to simulate onset of flowering of wild (e.g. birch) and domestic plants in Bavaria. In a first step we therefore determined both, a regional averaged optimum base temperature and temperature sum for the examined plant species in Bavaria. In the second step, the base temperatures were optimized to each site for the simulation period 2001-2010. Our hypothesis is that domestic plants depend much less on the regional weather conditions than wild plants do, due to low and high genetic variability, respectively. If so, the observed base temperatures of wild plants are smaller for low annual average temperatures and higher for high annual average temperatures. In the cases of domestic plants the optimized base

  17. Comparison of MODIS Satellite Land Surface Temperature with Air Temperature along a 5000-metre Elevation Transect on Kilimanjaro, Tanzania.

    NASA Astrophysics Data System (ADS)

    Pepin, N. C.; Williams, R.; Maeda, E. E.

    2015-12-01

    There is concern that high elevations may be warming more rapidly than lower elevations, but there is a lack of observational data from weather stations in the high mountains. One alternative data source is satellite LST (Land Surface Temperature) which has extensive spatial coverage. This study compares instantaneous values of LST (1030 and 2230 local solar time) as measured by the MODIS MOD11A2 product at 1 km resolution with equivalent screen level air temperatures (in the same pixel) measured from a transect of 22 in situ weather stations across Kilimanjaro ranging in elevation from 990 to 5803 m. Data consists of 11 years on the SW slope and 3 years on the NE slope, equating to >500 and ~140 octtads (8-day periods) respectively. Results show substantial differences between LST and local air temperature, sometimes up to 20C. During the day the LST tends to be higher than air temperature and the reverse is true at night. The differences show large variance, particularly during the daytime, and tend to increase with elevation, particularly on the NE slope of the mountain which faces the sun when the daytime observations are taken (1030 LST). Differences between LST and air temperature are larger in the dry seasons (JF and JJAS), and reduce when conditions are more cloudy. Systematic relationships with cloud cover and vegetation characteristics (as measured by NDVI and MAIAC for the same pixel) are displayed. More vegetation reduces daytime surface heating above the air temperature, but this relationship weakens with elevation. Nighttime differences are more stable and show no relationship with vegetation indices. Therefore the predictability of the LST/air temperature differences reduces at high elevations and it is therefore much more challenging to use satellite data at high elevations to complement in situ air temperature measurements for climate change assessments, especially for daytime maximum temperatures.

  18. Homogenisation of minimum and maximum air temperature in northern Portugal

    NASA Astrophysics Data System (ADS)

    Freitas, L.; Pereira, M. G.; Caramelo, L.; Mendes, L.; Amorim, L.; Nunes, L.

    2012-04-01

    Homogenization of minimum and maximum air temperature has been carried out for northern Portugal for the period 1941-2010. The database corresponds to the values of the monthly arithmetic averages calculated from daily values observed at stations within the network of stations managed by the national Institute of Meteorology (IM). Some of the weather stations of IM's network are collecting data for more than a century; however, during the entire observing period, some factors have affected the climate series and have to be considered such as, changes in the station surroundings and changes related to replacement of manually operated instruments. Besides these typical changes, it is of particular interest the station relocation to rural areas or to the urban-rural interface and the installation of automatic weather stations in the vicinity of the principal or synoptic stations with the aim of replacing them. The information from these relocated and new stations was merged to produce just one but representative time series of that site. This process starts at the end 90's and the information of the time series fusion process constitutes the set of metadata used. Two basic procedures were performed: (i) preliminary statistical and quality control analysis; and, (ii) detection and correction of problems of homogeneity. In the first case, was developed and used software for quality control, specifically dedicated for the detection of outliers, based on the quartile values of the time series itself. The analysis of homogeneity was performed using the MASH (Multiple Analysis of Series for Homogenisation) and HOMER, which is a software application developed and recently made available within the COST Action ES0601 (COST-ES0601, 2012). Both methods provide a fast quality control of the original data and were developed for automatic processing, analyzing, homogeneity testing and adjusting of climatological data, but manual usage is also possible. Obtained results with both

  19. Skin sites to predict deep-body temperature while wearing firefighters' personal protective equipment during periodical changes in air temperature.

    PubMed

    Kim, Siyeon; Lee, Joo-Young

    2016-04-01

    The aim of this study was to investigate stable and valid measurement sites of skin temperatures as a non-invasive variable to predict deep-body temperature while wearing firefighters' personal protective equipment (PPE) during air temperature changes. Eight male firefighters participated in an experiment which consisted of 60-min exercise and 10-min recovery while wearing PPE without self-contained breathing apparatus (7.75 kg in total PPE mass). Air temperature was periodically fluctuated from 29.5 to 35.5 °C with an amplitude of 6 °C. Rectal temperature was chosen as a deep-body temperature, and 12 skin temperatures were recorded. The results showed that the forehead and chest were identified as the most valid sites to predict rectal temperature (R(2) = 0.826 and 0.824, respectively) in an environment with periodically fluctuated air temperatures. This study suggests that particular skin temperatures are valid as a non-invasive variable when predicting rectal temperature of an individual wearing PPE in changing ambient temperatures. Practitioner Summary: This study should offer assistance for developing a more reliable indirect indicating system of individual heat strain for firefighters in real time, which can be used practically as a precaution of firefighters' heat-related illness and utilised along with physiological monitoring. PMID:26214379

  20. Simulations of the climate effects of European air quality legislation in Pegasos

    NASA Astrophysics Data System (ADS)

    O'Donnell, Declan; Laaksonen, Ari; Maenhout, Greet; Dentener, Frank

    2015-04-01

    Pegasos is a large-scale, multiyear project that studies the interactions between air quality and climate employing laboratory and field measurements, and modelling studies from process level to global scale. Among the scientific questions addressed by Pegasos is that of how the reduction in particulate emissions resulting from the cumulative European air quality legislation (which has been progressively enacted since 1970) affects the climate system. To investigate this question, we have performed multi-decadal climate simulations using the coupled Max Planck Institute Earth System Model (MPI-ESM) together with the fully integrated aerosol model HAM, using purpose-built emission inventories representing (i) a best estimate of modern-day (here taken as the year 2010) emissions and (ii) a scenario in which no European Union (EU) air quality legislation had been enacted. The difference between the two amounts to a total anthropogenic emission of some 2.8 Tg/yr PM2.5. The simulations were run using greenhouse gas concentrations fixed at 2010 levels and were each of 40 simulated years after spinup. As expected, the largest reductions in particulate matter concentrations are found over Europe. In contrast, the strongest climate signals are found in regions remote from the particulate emission sources. The global mean multiannual surface temperature does not show a strong response to the emission reductions, differing by less than 0.1°C between the simulations. However, this masks large regional differences, with the strongest signal not in the emission source regions, but in the Arctic and central Siberia, where the simluated temperature difference reaches over 1°C. Precipitation changes also show a stronger signal far from the source regions: tropical precipitation is affected to a greater degree than the extratropical, which seems to be due to the changes in the hemispherically asymmetric aerosol forcing influencing the location of the Intertropical Convergence Zone

  1. Air-Cooled Design of a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization Systems

    NASA Technical Reports Server (NTRS)

    Mulloth, Lila M.; Affleck, Dave L.; Rosen, Micha; LeVan, M. Douglas; Wang, Yuan; Cavalcante, Celio L.

    2004-01-01

    The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no rapidly moving parts. This paper discusses the mechanical design and the results of thermal model validation tests of a TSAC that uses air as the cooling medium.

  2. Numerical simulation of heat transfer performance of an air-cooled steam condenser in a thermal power plant

    NASA Astrophysics Data System (ADS)

    Gao, Xiufeng; Zhang, Chengwei; Wei, Jinjia; Yu, Bo

    2009-09-01

    Numerical simulation of the thermal-flow characteristics and heat transfer performance is made of an air-cooled steam condenser (ACSC) in a thermal power plant by considering the effects of ambient wind speed and direction, air-cooled platform height, location of the main factory building and terrain condition. A simplified physical model of the ACSC combined with the measured data as input parameters is used in the simulation. The wind speed effects on the heat transfer performance and the corresponding steam turbine back pressure for different heights of the air-cooled platform are obtained. It is found that the turbine back pressure (absolute pressure) increases with the increase of wind speed and the decrease of platform height. This is because wind can not only reduce the flowrate in the axial fans, especially at the periphery of the air-cooled platform, due to cross-flow effects, but also cause an air temperature increase at the fan inlet due to hot air recirculation, resulting in the deterioration of the heat transfer performance. The hot air recirculation is found to be the dominant factor because the main factory building is situated on the windward side of the ACSC.

  3. DEVELOPMENT OF A WINDOWS-BASED INDOOR AIR QUALITY SIMULATION SOFTWARE PACKAGE

    EPA Science Inventory

    A Microsoft Windows-based indoor air quality (IAQ) simulation software package has been developed and is currently undergoing small-scale beta test and quality assurance review. Tentatively named Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure, or STKi for sho...

  4. 40 CFR 86.162-03 - Approval of alternative air conditioning test simulations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... initiative, the Administrator will approve a simulation of the environmental cell for air conditioning test... environmental cell test data for the range of vehicles to be covered by the simulation including items such as the tailpipe emissions, air conditioning compressor load, and fuel economy. (2) For any...

  5. Soil Moisture Active/Passive (SMAP) Forward Brightness Temperature Simulator

    NASA Technical Reports Server (NTRS)

    Peng, Jinzheng; Peipmeier, Jeffrey; Kim, Edward

    2012-01-01

    The SMAP is one of four first-tier missions recommended by the US National Research Council's Committee on Earth Science and Applications from Space (Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, Space Studies Board, National Academies Press, 2007) [1]. It is to measure the global soil moisture and freeze/thaw from space. One of the spaceborne instruments is an L-band radiometer with a shared single feedhorn and parabolic mesh reflector. While the radiometer measures the emission over a footprint of interest, unwanted emissions are also received by the antenna through the antenna sidelobes from the cosmic background and other error sources such as the Sun, the Moon and the galaxy. Their effects need to be considered accurately, and the analysis of the overall performance of the radiometer requires end-to-end performance simulation from Earth emission to antenna brightness temperature, such as the global simulation of L-band brightness temperature simulation over land and sea [2]. To assist with the SMAP radiometer level 1B algorithm development, the SMAP forward brightness temperature simulator is developed by adapting the Aquarius simulator [2] with necessary modifications. This poster presents the current status of the SMAP forward brightness simulator s development including incorporating the land microwave emission model and its input datasets, and a simplified atmospheric radiative transfer model. The latest simulation results are also presented to demonstrate the ability of supporting the SMAP L1B algorithm development.

  6. Optimization and simulation of low-temperature combustion and heat transfer in an Uhde carbonization furnace

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Zhang, Yongfa; Wang, Ying; Chen, Lei; Liu, Gaihuan

    2015-12-01

    The temperature distribution inside a low-temperature combustion chamber with circuited flame path during the low temperature pyrolysis of lignite was simulated using the computational fluid dynamics software FLUENT. The temperature distribution in the Uhde combustion chamber showed that the temperature is very non-uniform and could therefore not meet the requirements for industrial heat transfer. After optimizing the furnace, by adding a self-made gas-guide structure to the heat transfer section as well as adjusting the gas flow size in the flame path, the temperature distribution became uniform, and the average temperature (550-650 °C) became suitable for industrial low-temperature pyrolysis. The Realizable k-epsilon model, P-1 model, and the Non-premixed model were used to calculate the temperature distribution for the combustion of coke-oven gas and air inside the combustion chamber. Our simulation is consistent with our experimental results within an error range of 40-80 °C. The one-dimensional unsteady state heat conduction differential equation ρ nolimits_{coal} Cnolimits_{coal} partial T/partial t = partial /partial x(λ partial T/partial x) can be used to calculate the heat transfer process. Our results can serve as a first theoretical base and may enable technological advances with regard to lignite pyrolysis.

  7. Determination of needed parameters for measuring temperature fields in air by thermography

    NASA Astrophysics Data System (ADS)

    Pešek, Martin; Pavelek, Milan

    2012-04-01

    The aim of this article is the parameters determination of equipment for measuring temperature fields in air using an infrared camera. This method is based on the visualization of temperature fields in an auxiliary material, which is inserted into the non-isothermal air flow. The accuracy of air temperature measurement (or of surface temperature of supplies) by this method depends especially on (except for parameters of infrared camera) the determination of the static and the dynamic qualities of auxiliary material. The emissivity of support material is the static quality and the dynamic quality is time constant. Support materials with a high emissivity and a low time constant are suitable for the measurement. The high value of emissivity results in a higher measurement sensitivity and the radiation temperature independence. In this article the emissivity of examined kinds of auxiliary materials (papers and textiles) is determined by temperature measuring of heated samples by a calibrated thermocouple and by thermography, with the emissivity setting on the camera to 1 and with the homogeneous radiation temperature. Time constants are determined by a step change of air temperature in the surrounding of auxiliary material. The time constant depends mainly on heat transfer by the convection from the air into the auxiliary material. That is why the effect of air temperature is examined in this article (or a temperature difference towards the environmental temperature) and the flow velocity on the time constant with various types of auxiliary materials. The obtained results allow to define the conditions for using the method of measurement of temperature fields in air during various heating and air conditioning applications.

  8. Effect of pyrolysis temperature and air flow on toxicity of gases from a polycarbonate polymer

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Brick, V. E.; Brauer, D. P.

    1978-01-01

    A polycarbonate polymer was evaluated for toxicity of pyrolysis gases generated at various temperatures without forced air flow and with 1 L/min air flow, using the toxicity screening test method developed at the University of San Francisco. Time to various animal responses decreased with increasing pyrolysis temperature over the range from 500 C to 800 C. There appeared to be no significant toxic effects at 400 C and lower temperatures.

  9. The EUSTACE project: delivering global, daily information on surface air temperature

    NASA Astrophysics Data System (ADS)

    Morice, C. P.; Rayner, N. A.; Auchmann, R.; Bessembinder, J.; Bronnimann, S.; Brugnara, Y.; Conway, E. A.; Ghent, D.; Good, E.; Herring, K.; Kennedy, J.; Lindgren, F.; Madsen, K. S.; Merchant, C. J.; van der Schrier, G.; Stephens, A.; Tonboe, R. T.; Waterfall, A. M.; Mitchelson, J.; Woolway, I.

    2015-12-01

    Day-to-day variations in surface air temperature affect society in many ways; however, daily surface air temperature measurements are not available everywhere. A global daily analysis cannot be achieved with measurements made in situ alone, so incorporation of satellite retrievals is needed. To achieve this, we must develop an understanding of the relationships between traditional (land and marine) surface air temperature measurements and retrievals of surface skin temperature from satellite measurements, i.e. Land Surface Temperature, Ice Surface Temperature, Sea Surface Temperature and Lake Surface Water Temperature. These relationships can be derived either empirically or with the help of a physical model.Here we discuss the science needed to produce a fully-global daily analysis (or ensemble of analyses) of surface air temperature on the centennial scale, integrating different ground-based and satellite-borne data types. Information contained in the satellite retrievals would be used to create globally-complete fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place. As the data volumes involved are considerable, such work needs to include development of new "Big Data" analysis methods.We will present plans and progress along this road in the EUSTACE project (2015-June 2018), i.e.: • providing new, consistent, multi-component estimates of uncertainty in surface skin temperature retrievals from satellites; • identifying inhomogeneities in daily surface air temperature measurement series from weather stations and correcting for these over Europe; • estimating surface air temperature over all surfaces of Earth from surface skin temperature retrievals; • using new statistical techniques to provide information on higher spatial and temporal scales than currently available, making optimum use of information in data-rich eras.Information will also be given on how interested users can become

  10. 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

  11. Some Effects of Air and Fuel Oil Temperatures on Spray Penetration and Dispersion

    NASA Technical Reports Server (NTRS)

    Gelalles, A G

    1930-01-01

    Presented here are experimental results obtained from a brief investigation of the appearance, penetration, and dispersion of oil sprays injected into a chamber of highly heated air at atmospheric pressure. The development of single sprays injected into a chamber containing air at room temperature and at high temperature was recorded by spray photography equipment. A comparison of spray records showed that with the air at the higher temperature, the spray assumed the appearance of thin, transparent cloud, the greatest part of which rapidly disappeared from view. With the chamber air at room temperature, a compact spray with an opaque core was obtained. Measurements of the records showed a decrease in penetration and an increase in the dispersion of the spray injected into the heated air. No ignition of the fuel injected was observed or recorded until the spray particles came in contact with the much hotter walls of the chamber about 0.3 second after the start of injection.

  12. Stress induced by hooking, net towing, elevated sea water temperature and air in sablefish: Lack of concordance between mortality and physiological measures of stress

    USGS Publications Warehouse

    Davis, M.W.; Olla, B.L.; Schreck, C.B.

    2001-01-01

    In a series of laboratory studies designed to simulate bycatch processes, sablefish Anoplopoma fimbria were either hooked for up to 24 h or towed in a net for 4 h and then subjected to an abrupt transfer to elevated sea water temperature and air. Mortality did not result from hooking or net towing followed by exposure to air, but increased for both capture methods as fish were exposed to elevated temperatures, reflecting the magnifying effect of elevated temperature on mortality. Hooking and exposure to air resulted in increased plasma cortisol and lactate concentrations, while the combination of hooking and exposure to elevated temperature and air resulted in increased lactate and potassium concentrations. In fish that were towed in a net and exposed to air, cortisol, lactate, potassium and sodium concentrations increased, but when subjected to elevated temperature and air, no further increases occurred above the concentrations induced by net towing and air, suggesting a possible maximum of the physiological stress response. The results suggest that caution should be exercised when using physiological measures to quantify stress induced by capture and exposure to elevated temperature and air, that ultimately result in mortality, since the connections between physiological stress and mortality in bycatch processes remain to be fully understood.

  13. Simulation of spectral effects of Asian dusts on the AIRS radiances and its application to retrieval of dust properties

    NASA Astrophysics Data System (ADS)

    Han, Hyo-Jin; Sohn, Byung-Ju; Huang, Hung-Lung; Weisz, Elisabeth

    2010-11-01

    In order to examine the effect of Asian dusts and apply to retrieval of dust properties, radiances measured by AIRS were simulated using the RTTOV-9 model. The model has been implemented with new optical properties for Asian dusts; refractive indices of mineral dust in the OPAC library and size distribution of Asian dusts retrieved from 10 years of skyradiometer measurements at Dunhuang, China. The simulations were performed using the implemented model, but with specification of AOT and height of dust layers obtained from CALIOP measurements. In the simulations, surface and atmospheric temperatures are from AIRS level 2 products while surface emissivity is specified with UW/CIMSS monthly mean global infrared surface emissivity data. Results show that effect of Asian dusts on AIRS spectra is substantial over infrared window regions (i.e.: 3.7 - 4.1 μm, 8.8 - 9.3 μm, 10 - 13 μm) for moderate and strong dust cases (AOT >= 0.5), while surface effect is dominant for weak dust cases (AOT < 0.5). Over 10 - 13 μm and 3.6 - 4.1 μm ranges, the simulation performances are improved when the dust effect is added. However, on the spectral range of 8.8 - 9.3 μm, the simulation overestimates radiances in comparison with AIRS measurements, probably because the mineral dust composition of OPAC does not coincide with the Asian dust. The comparison of simulated radiances with AIRS measurements shows a comparable quality for both clear and dusty conditions on the 10 - 13 μm and 3.6 - 4.1 μm ranges, suggesting that results can be incorporated for developing dust retrieval algorithm from hyperspectral images such as AIRS and IASI.

  14. Validation of AIRS V6 Surface Temperature over Greenland with GCN and NOAA Stations

    NASA Technical Reports Server (NTRS)

    Lee, Jae N.; Hearty, Thomas; Cullather, Richard; Nowicki, Sophie; Susskind, Joel

    2016-01-01

    This work compares the temporal and spatial characteristics of the AIRSAMSU (Atmospheric Infrared Sounder Advanced Microwave Sounding Unit A) Version 6 and MODIS (Moderate resolution Imaging Spectroradiometer) Collection 5 derived surface temperatures over Greenland. To estimate uncertainties in space-based surface temperature measurements, we re-projected the MODIS Ice Surface Temperature (IST) to 0.5 by 0.5 degree spatial resolution. We also re-gridded AIRS Skin Temperature (Ts) into the same grid but classified with different cloud conditions and surface types. These co-located data sets make intercomparison between the two instruments relatively straightforward. Using this approach, the spatial comparison between the monthly mean AIRS Ts and MODIS IST is in good agreement with RMS 2K for May 2012. This approach also allows the detection of any long-term calibration drift and the careful examination of calibration consistency in the MODIS and AIRS temperature data record. The temporal correlations between temperature data are also compared with those from in-situ measurements from GC-Net (GCN) and NOAA stations. The coherent time series of surface temperature evident in the correlation between AIRS Ts and GCN temperatures suggest that at monthly time scales both observations capture the same climate signal over Greenland. It is also suggested that AIRS surface air temperature (Ta) can be used to estimate the boundary layer inversion.

  15. Attribution of precipitation changes on ground-air temperature offset: Granger causality analysis

    NASA Astrophysics Data System (ADS)

    Cermak, Vladimir; Bodri, Louise

    2016-06-01

    This work examines the causal relationship between the value of the ground-air temperature offset and the precipitation changes for monitored 5-min data series together with their hourly and daily averages obtained at the Sporilov Geophysical Observatory (Prague). Shallow subsurface soil temperatures were monitored under four different land cover types (bare soil, sand, short-cut grass and asphalt). The ground surface temperature (GST) and surface air temperature (SAT) offset, ΔT(GST-SAT), is defined as the difference between the temperature measured at the depth of 2 cm below the surface and the air temperature measured at 5 cm above the surface. The results of the Granger causality test did not reveal any evidence of Granger causality for precipitation to ground-air temperature offsets on the daily scale of aggregation except for the asphalt pavement. On the contrary, a strong evidence of Granger causality for precipitation to the ground-air temperature offsets was found on the hourly scale of aggregation for all land cover types except for the sand surface cover. All results are sensitive to the lag choice of the autoregressive model. On the whole, obtained results contain valuable information on the delay time of ΔT(GST-SAT) caused by the rainfall events and confirmed the importance of using autoregressive models to understand the ground-air temperature relationship.

  16. Recommended direct simulation Monte Carlo collision model parameters for modeling ionized air transport processes

    NASA Astrophysics Data System (ADS)

    Swaminathan-Gopalan, Krishnan; Stephani, Kelly A.

    2016-02-01

    A systematic approach for calibrating the direct simulation Monte Carlo (DSMC) collision model parameters to achieve consistency in the transport processes is presented. The DSMC collision cross section model parameters are calibrated for high temperature atmospheric conditions by matching the collision integrals from DSMC against ab initio based collision integrals that are currently employed in the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) and Data Parallel Line Relaxation (DPLR) high temperature computational fluid dynamics solvers. The DSMC parameter values are computed for the widely used Variable Hard Sphere (VHS) and the Variable Soft Sphere (VSS) models using the collision-specific pairing approach. The recommended best-fit VHS/VSS parameter values are provided over a temperature range of 1000-20 000 K for a thirteen-species ionized air mixture. Use of the VSS model is necessary to achieve consistency in transport processes of ionized gases. The agreement of the VSS model transport properties with the transport properties as determined by the ab initio collision integral fits was found to be within 6% in the entire temperature range, regardless of the composition of the mixture. The recommended model parameter values can be readily applied to any gas mixture involving binary collisional interactions between the chemical species presented for the specified temperature range.

  17. Simulation of climate change impacts on grain sorghum production grown under free air CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Fu, Tongcheng; Ko, Jonghan; Wall, Gerard W.; Pinter, Paul J.; Kimball, Bruce A.; Ottman, Michael J.; Kim, Han-Yong

    2016-07-01

    Potential impacts of climate change on grain sorghum (Sorghum bicolor) productivity were investigated using the CERES-sorghum model in the Decision Support System for Agrotechnology Transfer v4.5. The model was first calibrated for a sorghum cultivar grown in a free air CO2 enrichment experiment at the University of Arizona, Maricopa, Arizona, USA in 1998. The model was then validated with an independent dataset collected in 1999. The simulated grain yield, growth, and soil water of sorghum for the both years were in statistical agreement with the corresponding measurements, respectively. Neither simulated nor measured yields responded to elevated CO2, but both were sensitive to water supply. The validated model was then applied to simulate possible effects of climate change on sorghum grain yield and water use efficiency in western North America for the years 2080-2100. The projected CO2 fertilizer effect on grain yield was dominated by the adverse effect of projected temperature increases. Therefore, temperature appears to be a dominant driver of the global climate change influencing future sorghum productivity. These results suggest that an increase in water demand for sorghum production should be anticipated in a future high-CO2 world.

  18. Simulation of temperature fields in arc and beam welding

    NASA Astrophysics Data System (ADS)

    Mahrle, A.; Schmidt, J.; Weiss, D.

    Heat and mass transfer in arc and beam welding is considered. The main objectives are analysis of the heat transfer in the weld pool and the workpiece and to demonstrate how computer simulation can be used as a tool to predict the temperature distribution as the determining element of the heat effects of welding. Simulation results of two particular welding processes are compared and validated with measurements.

  19. A comparison of urban heat islands mapped using skin temperature, air temperature, and apparent temperature (Humidex), for the greater Vancouver area.

    PubMed

    Ho, Hung Chak; Knudby, Anders; Xu, Yongming; Hodul, Matus; Aminipouri, Mehdi

    2016-02-15

    Apparent temperature is more closely related to mortality during extreme heat events than other temperature variables, yet spatial epidemiology studies typically use skin temperature (also known as land surface temperature) to quantify heat exposure because it is relatively easy to map from satellite data. An empirical approach to map apparent temperature at the neighborhood scale, which relies on publicly available weather station observations and spatial data layers combined in a random forest regression model, was demonstrated for greater Vancouver, Canada. Model errors were acceptable (cross-validated RMSE=2.04 °C) and the resulting map of apparent temperature, calibrated for a typical hot summer day, corresponded well with past temperature research in the area. A comparison with field measurements as well as similar maps of skin temperature and air temperature revealed that skin temperature was poorly correlated with both air temperature (R(2)=0.38) and apparent temperature (R(2)=0.39). While the latter two were more similar (R(2)=0.87), apparent temperature was predicted to exceed air temperature by more than 5 °C in several urban areas as well as around the confluence of the Pitt and Fraser rivers. We conclude that skin temperature is not a suitable proxy for human heat exposure, and that spatial epidemiology studies could benefit from mapping apparent temperature, using an approach similar to the one reported here, to better quantify differences in heat exposure that exist across an urban landscape. PMID:26706765

  20. Temperature dependence of protein hydration hydrodynamics by molecular dynamics simulations.

    SciTech Connect

    Lau, E Y; Krishnan, V V

    2007-07-18

    The dynamics of water molecules near the protein surface are different from those of bulk water and influence the structure and dynamics of the protein itself. To elucidate the temperature dependence hydration dynamics of water molecules, we present results from the molecular dynamic simulation of the water molecules surrounding two proteins (Carboxypeptidase inhibitor and Ovomucoid) at seven different temperatures (T=273 to 303 K, in increments of 5 K). Translational diffusion coefficients of the surface water and bulk water molecules were estimated from 2 ns molecular dynamics simulation trajectories. Temperature dependence of the estimated bulk water diffusion closely reflects the experimental values, while hydration water diffusion is retarded significantly due to the protein. Protein surface induced scaling of translational dynamics of the hydration waters is uniform over the temperature range studied, suggesting the importance protein-water interactions.

  1. METCAN updates for high temperature composite behavior: Simulation/verification

    NASA Technical Reports Server (NTRS)

    Lee, H.-J.; Murthy, P. L. N.; Chamis, Christos C.

    1991-01-01

    The continued verification (comparisons with experimental data) of the METCAN (Metal Matrix Composite Analyzer) computer code is updated. Verification includes comparisons at room and high temperatures for two composites, SiC/Ti-15-3 and SiC/Ti-6-4. Specifically, verification of the SiC/Ti-15-3 composite includes comparisons of strength, modulus, and Poisson's ratio as well as stress-strain curves for four laminates at room temperature. High temperature verification includes comparisons of strength and stress-strain curves for two laminates. Verification of SiC/Ti-6-4 is for a transverse room temperature stress-strain curve and comparisons for transverse strength at three temperatures. Results of the verification indicates that METCAN can be used with confidence to simulate the high temperature nonlinear behavior of metal matrix composites.

  2. Comparison of climate model simulated and observed borehole temperature profiles

    NASA Astrophysics Data System (ADS)

    Gonzalez-Rouco, J. F.; Stevens, M. B.; Beltrami, H.; Goosse, H.; Rath, V.; Zorita, E.; Smerdon, J.

    2009-04-01

    Advances in understanding climate variability through the last millennium lean on simulation and reconstruction efforts. Progress in the integration of both approaches can potentially provide new means of assessing confidence on model projections of future climate change, of constraining the range of climate sensitivity and/or attributing past changes found in proxy evidence to external forcing. This work addresses specifically possible strategies for comparison of paleoclimate model simulations and the information recorded in borehole temperature profiles (BTPs). First efforts have allowed to design means of comparison of model simulated and observed BTPs in the context of the climate of the last millennium. This can be done by diffusing the simulated temperatures into the ground in order to produce synthetic BTPs that can be in turn assigned to collocated, real BTPs. Results suggest that there is sensitivity of borehole temperatures at large and regional scales to changes in external forcing over the last centuries. The comparison between borehole climate reconstructions and model simulations may also be subjected to non negligible uncertainties produced by the influence of past glacial and Holocene changes. While the thermal climate influence of the last deglaciation can be found well below 1000 m depth, such type of changes can potentially exert an influence on our understanding of subsurface climate in the top ca. 500 m. This issue is illustrated in control and externally forced climate simulations of the last millennium with the ECHO-G and LOVECLIM models, respectively.

  3. Modelling near subsurface temperature with mixed type boundary condition for transient air temperature and vertical groundwater flow

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev Ranjan; Ramana, D. V.; Singh, R. N.

    2012-10-01

    Near-subsurface temperatures have signatures of climate change. Thermal models of subsurface have been constructed by prescribing time dependent Dirichlet type boundary condition wherein the temperature at the soil surface is prescribed and depth distribution of temperature is obtained. In this formulation it is not possible to include the relationship between air temperatures and the temperature of soil surface. However, if one uses a Robin type boundary condition, a transfer coefficient relates the air and soil surface temperatures which helps to determine both the temperature at the surface and at depth given near surface air temperatures. This coefficient is a function of meteorological conditions and is readily available. We have developed such a thermal model of near subsurface region which includes both heat conduction and advection due to groundwater flows and have presented numerical results for changes in the temperature-depth profiles for different values of transfer coefficient and groundwater flux. There are significant changes in temperature and depth profiles due to changes in the transfer coefficient and groundwater flux. The analytical model will find applications in the interpretation of the borehole geothermal data to extract both climate and groundwater flow signals.

  4. Comparison of Near-Surface Air Temperatures and MODIS Ice-Surface Temperatures at Summit, Greenland (2008-2013)

    NASA Technical Reports Server (NTRS)

    Shuman, Christopher A.; Hall, Dorothy K.; DiGirolamo, Nicolo E.; Mefford, Thomas K.; Schnaubelt, Michael J.

    2014-01-01

    We have investigated the stability of the MODerate resolution Imaging Spectroradiometer (MODIS) infrared-derived ice surface temperature (IST) data from Terra for use as a climate quality data record. The availability of climate quality air temperature data (TA) from a NOAA Global Monitoring Division observatory at Greenlands Summit station has enabled this high temporal resolution study of MODIS ISTs. During a 5 year period (July 2008 to August 2013), more than 2500 IST values were compared with 3-minute average TA values derived from the 1-minute data from NOAAs primary 2 m air temperature sensor. These data enabled an expected small offset between air and surface temperatures at this the ice sheet location to be investigated over multiple annual cycles.

  5. Investigation of the impact of extreme air temperature on river water temperature: case study of the heat episode 2013.

    NASA Astrophysics Data System (ADS)

    Weihs, Philipp; Trimmel, Heidelinde; Goler, Robert; Formayer, Herbert; Holzapfel, Gerda; Rauch, Hans Peter

    2014-05-01

    Water stream temperature is a relevant factor for water quality since it is an important driver of water oxygen content and in turn also reduces or increases stress on the aquatic fauna. The water temperature of streams is determined by the source and inflow water temperature, by the energy balance at the stream surface and by the hydrological regime of the stream. Main factors driving the energy balance of streams are radiation balance and air temperature which influences the sensitive and latent heat flux. The present study investigates the impact of the heat episode of summer 2013 on water temperature of two lowland rivers in south eastern Austria. Within the scope of the project BIO_CLIC routine measurements of water temperature at 33 locations alongside the rivers Pinka and Lafnitz have been performed since spring 2012. In addition meteorological measurements of global shortwave and longwave radiation, air temperature, wind and air humidity have been carried out during this time. For the same time period, data of discharge and water levels of both rivers were provided by the public hydrological office. The heat episode of summer 2013 started, according to the Kysely- definition, on 18 July and lasted until 14 August. The highest air temperature ever recorded in Austria was reported on 8 August at 40.5°C. In Güssing, which is located within the project area, 40.0 °C were recorded. In the lower reaches of the river Pinka, at the station Burg the monthly mean water temperature of August 2013 was with more than 22°C, 1°C higher than the mean water temperature of the same period of the previous years. At the same station, the maximum water temperature of 27.1°C was recorded on 29 July, 9 days prior to the air temperature record. Analysis shows that at the downstream stations the main driving parameter is solar radiation whereas at the upstream stations a better correlation between air temperature and water temperature is obtained. Using the extensive data set

  6. A Distributed Simulation Facility to Support Human Factors Research in Advanced Air Transportation Technology

    NASA Technical Reports Server (NTRS)

    Amonlirdviman, Keith; Farley, Todd C.; Hansman, R. John, Jr.; Ladik, John F.; Sherer, Dana Z.

    1998-01-01

    A distributed real-time simulation of the civil air traffic environment developed to support human factors research in advanced air transportation technology is presented. The distributed environment is based on a custom simulation architecture designed for simplicity and flexibility in human experiments. Standard Internet protocols are used to create the distributed environment, linking all advanced cockpit simulator, all Air Traffic Control simulator, and a pseudo-aircraft control and simulation management station. The pseudo-aircraft control station also functions as a scenario design tool for coordinating human factors experiments. This station incorporates a pseudo-pilot interface designed to reduce workload for human operators piloting multiple aircraft simultaneously in real time. The application of this distributed simulation facility to support a study of the effect of shared information (via air-ground datalink) on pilot/controller shared situation awareness and re-route negotiation is also presented.

  7. Geographical and Geomorphological Effects on Air Temperatures in the Columbia Basin's Signature Vineyards

    NASA Astrophysics Data System (ADS)

    Olson, L.; Pogue, K. R.; Bader, N.

    2012-12-01

    The Columbia Basin of Washington and Oregon is one of the most productive grape-growing areas in the United States. Wines produced in this region are influenced by their terroir - the amalgamation of physical and cultural elements that influence grapes grown at a particular vineyard site. Of the physical factors, climate, and in particular air temperature, has been recognized as a primary influence on viticulture. Air temperature directly affects ripening in the grapes. Proper fruit ripening, which requires precise and balanced levels of acid and sugar, and the accumulation of pigment in the grape skin, directly correlates with the quality of wine produced. Many features control air temperature within a particular vineyard. Elevation, latitude, slope, and aspect all converge to form complex relationships with air temperatures; however, the relative degree to which these attributes affect temperatures varies between regions and is not well understood. This study examines the influence of geography and geomorphology on air temperatures within the American Viticultural Areas (AVAs) of the Columbia Basin in eastern Washington and Oregon. The premier vineyards within each AVA, which have been recognized for producing high-quality wine, were equipped with air temperature monitoring stations that collected hourly temperature measurements. A variety of temperature statistics were calculated, including daily average, maximum, and minimum temperatures. From these values, average diurnal variation and growing degree-days (10°C) were calculated. A variety of other statistics were computed, including date of first and last frost and time spent below a minimum temperature threshold. These parameters were compared to the vineyard's elevation, latitude, slope, aspect, and local topography using GPS, ArcCatalog, and GIS in an attempt to determine their relative influences on air temperatures. From these statistics, it was possible to delineate two trends of temperature variation

  8. CONCENTRATIONS OF TOXIC AIR POLLUTANTS IN THE U.S. SIMULATED BY AN AIR QUALITY MODEL

    EPA Science Inventory

    As part of the US National Air Toxics Assessment, we have applied the Community Multiscale Air Quality Model, CMAQ, to study the concentrations of twenty gas-phase, toxic, hazardous air pollutants (HAPs) in the atmosphere over the continental United States. We modified the Carbo...

  9. Oxide modified air electrode surface for high temperature electrochemical cells

    DOEpatents

    Singh, Prabhakar; Ruka, Roswell J.

    1992-01-01

    An electrochemical cell is made having a porous cermet electrode (16) and a porous lanthanum manganite electrode (14), with solid oxide electrolyte (15) between them, where the lanthanum manganite surface next to the electrolyte contains a thin discontinuous layer of high surface area cerium oxide and/or praseodymium oxide, preferably as discrete particles (30) in contact with the air electrode and electrolyte.

  10. Measured Performance of a Low Temperature Air Source Heat Pump

    SciTech Connect

    R.K. Johnson

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.

  11. Combustion of Gaseous Fuels with High Temperature Air in Normal- and Micro-gravity Conditions

    NASA Technical Reports Server (NTRS)

    Wang, Y.; Gupta, A. K.

    2001-01-01

    The objective of this study is determine the effect of air preheat temperature on flame characteristics in normal and microgravity conditions. We have obtained qualitative (global flame features) and some quantitative information on the features of flames using high temperature combustion air under normal gravity conditions with propane and methane as the fuels. This data will be compared with the data under microgravity conditions. The specific focus under normal gravity conditions has been on determining the global flame features as well as the spatial distribution of OH, CH, and C2 from flames using high temperature combustion air at different equivalence ratio.

  12. Evaluation of the meteorological forcing used for the Air Quality Model Evaluation International Initiative (AQMEII) air quality simulations

    NASA Astrophysics Data System (ADS)

    Vautard, Robert; Moran, Michael D.; Solazzo, Efisio; Gilliam, Robert C.; Matthias, Volker; Bianconi, Roberto; Chemel, Charles; Ferreira, Joana; Geyer, Beate; Hansen, Ayoe B.; Jericevic, Amela; Prank, Marje; Segers, Arjo; Silver, Jeremy D.; Werhahn, Johannes; Wolke, Ralf; Rao, S. T.; Galmarini, Stefano

    2012-06-01

    Accurate regional air pollution simulation relies strongly on the accuracy of the mesoscale meteorological simulation used to drive the air quality model. The framework of the Air Quality Model Evaluation International Initiative (AQMEII), which involved a large international community of modeling groups in Europe and North America, offered a unique opportunity to evaluate the skill of mesoscale meteorological models for two continents for the same period. More than 20 groups worldwide participated in AQMEII, using several meteorological and chemical transport models with different configurations. The evaluation has been performed over a full year (2006) for both continents. The focus for this particular evaluation was meteorological parameters relevant to air quality processes such as transport and mixing, chemistry, and surface fluxes. The unprecedented scale of the exercise (one year, two continents) allowed us to examine the general characteristics of meteorological models' skill and uncertainty. In particular, we found that there was a large variability between models or even model versions in predicting key parameters such as surface shortwave radiation. We also found several systematic model biases such as wind speed overestimations, particularly during stable conditions. We conclude that major challenges still remain in the simulation of meteorology, such as nighttime meteorology and cloud/radiation processes, for air quality simulation.

  13. Improved Temperature Sounding and Quality Control Methodology Using AIRS/AMSU Data: The AIRS Science Team Version 5 Retrieval Algorithm

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John M.; Iredell, Lena; Keita, Fricky

    2009-01-01

    This paper describes the AIRS Science Team Version 5 retrieval algorithm in terms of its three most significant improvements over the methodology used in the AIRS Science Team Version 4 retrieval algorithm. Improved physics in Version 5 allows for use of AIRS clear column radiances in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of clear column radiances .R(sub i) for all channels. This new approach allows for the generation of more accurate values of .R(sub i) and T(p) under most cloud conditions. Secondly, Version 5 contains a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 also contains for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology, referred to as AIRS Version 5 AO, was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Results are shown comparing the relative performance of the AIRS Version 4, Version 5, and Version 5 AO for the single day, January 25, 2003. The Goddard DISC is now generating and distributing products derived using the AIRS Science Team Version 5 retrieval algorithm. This paper also described the Quality Control flags contained in the DISC AIRS/AMSU retrieval products and their intended use for scientific research purposes.

  14. Simulation and Experimental Analysis of Arc Motion Characteristics in Air Circuit Breaker

    NASA Astrophysics Data System (ADS)

    Niu, Chunping; Ding, Juwen; Wu, Yi; Yang, Fei; Dong, Delong; Fan, Xingyu; Rong, Mingzhe

    2016-03-01

    In this paper, to simulate the arc motion in an air circuit breaker (ACB), a three-dimensional magneto-hydrodynamic (MHD) model is developed, considering the influence of thermal radiation, the change of physical parameters of arc plasma and the nonlinear characteristic of ferromagnetic material. The distributions of pressure, temperature, gas flow and current density of arc plasma in the arc region are calculated. The simulation results show some phenomena which discourage arc interruption, such as back commutation and arc burning at the back of the splitter plate. To verify the simulation model, the arc motion is studied experimentally. The influences of the material and position of the innermost barrier plate are analyzed mainly. It proved that the model developed in this paper can efficiently simulate the arc motion. The results indicate that the insulation barrier plate close to the top of the splitter plate is conducive to the arc splitting, which leads to the significant increase of the arc voltage, so it is better for arc interruption. The research can provide methods and references to the optimization of ACB design. supported by National Key Basic Research Program of China (973 Program) (Nos. 2015CB251002, 6132620303), National Natural Science Foundation of China (Nos. 51221005, 51377128, 51577144), and the Fundamental Research Funds for the Central Universities, China

  15. Simulation and Prediction of North Pacific Sea Surface Temperature

    NASA Astrophysics Data System (ADS)

    Lienert, Fabian

    The first part of this thesis is an assessment of the ability of global climate models to reproduce observed features of the leading Empirical Orthogonal Function (EOF) mode of North Pacific sea surface temperature (SST) anomalies known as the Pacific Decadal Oscillation (PDO). My results are that 1) the models as group produce a realistic pattern of the PDO. The simulated variance of the PDO index is overestimated by roughly 30%. 2) The tropical influence on North Pacific SSTs is biased systematically in these models. The simulated response to El Nino-Southern Oscillation (ENSO) forcing is delayed compared to the observed response. This tendency is consistent with model biases toward deeper oceanic mixed layers in winter and spring and weaker air-sea feedbacks in the winter half-year. Model biases in mixed layer depths and air-sea feedbacks are also associated with a model mean ENSO-related signal in the North Pacific whose amplitude is overestimated by roughly 30%. Finally, model power spectra of the PDO signal and its ENSO-forced component are "redder" than observed due to errors originating in the tropics and extratropics. 3) The models are quite successful at capturing the influence of both the tropical Pacific related and the extratropical part of the PDO on North American surface temperature. 4) The models capture some of the influence of the PDO on North American precipitation mainly due to its tropical Pacific related part. In the second part of this thesis, I investigate the ability of one such coupled ocean-atmosphere climate model, carefully initialized with observations, to dynamically predict the future evolution of the PDO on seasonal to decadal time scales. I find that 1) CHFP2 is successful at predicting the PDO at the seasonal time scale measured by mean-square skill score and correlation skill. Weather "noise" unpredictable at the seasonal time scale generated by substantial North Pacific storm track activity that coincides with a shallow oceanic

  16. Influence of lunar topography on simulated surface temperature

    NASA Astrophysics Data System (ADS)

    Zhiguo, Meng; Yi, Xu; Zhanchuan, Cai; Shengbo, Chen; Yi, Lian; Hang, Huang

    2014-11-01

    The surface temperature of the Moon is one of the essential parameters for the lunar exploration, especially to evaluate the Moon thermophysical features. The distribution of the temperature is heavily influenced by the Moon topography, which, however, is rarely studied in the state-of-art surface temperature models. Therefore, this paper takes the Moon topography into account to improve the surface temperature model, Racca model. The main parameters, such as slopes along the longitude and latitude directions, are estimated with the topography data from Chang'E-1 satellite and the Horn algorithm. Then the effective solar illumination model is then constructed with the slopes and the relative position to the subsolar point. Finally, the temperature distribution over the Moon surface is obtained with the effective illumination model and the improved Racca model. The results indicate that the distribution of the temperature is very sensitive to the fluctuation of the Moon surface. The change of the surface temperature is up to 150 K in some places compared to the result without considering the topography. In addition, the variation of the surface temperature increases with the distance from the subsolar point and the elevation, along both latitude and longitude directions. Furthermore, the simulated surface temperature coincides well with the brightness temperature in 37 GHz observed by the microwave sounder onboard Chang'E-2 satellite. The corresponded emissivity map not only eliminates the influence of the topography, but also hints the inherent properties of the lunar regolith just below the surface. Last but not the least, the distribution of the permanently shadowed regions (PSRs) in the lunar pole area is also evaluated with the simulated surface temperature result.

  17. Turbulent Transfer Coefficients and Calculation of Air Temperature inside Tall Grass Canopies in Land Atmosphere Schemes for Environmental Modeling.

    NASA Astrophysics Data System (ADS)

    Mihailovic, D. T.; Alapaty, K.; Lalic, B.; Arsenic, I.; Rajkovic, B.; Malinovic, S.

    2004-10-01

    A method for estimating profiles of turbulent transfer coefficients inside a vegetation canopy and their use in calculating the air temperature inside tall grass canopies in land surface schemes for environmental modeling is presented. The proposed method, based on K theory, is assessed using data measured in a maize canopy. The air temperature inside the canopy is determined diagnostically by a method based on detailed consideration of 1) calculations of turbulent fluxes, 2) the shape of the wind and turbulent transfer coefficient profiles, and 3) calculation of the aerodynamic resistances inside tall grass canopies. An expression for calculating the turbulent transfer coefficient inside sparse tall grass canopies is also suggested, including modification of the corresponding equation for the wind profile inside the canopy. The proposed calculations of K-theory parameters are tested using the Land Air Parameterization Scheme (LAPS). Model outputs of air temperature inside the canopy for 8 17 July 2002 are compared with micrometeorological measurements inside a sunflower field at the Rimski Sancevi experimental site (Serbia). To demonstrate how changes in the specification of canopy density affect the simulation of air temperature inside tall grass canopies and, thus, alter the growth of PBL height, numerical experiments are performed with LAPS coupled with a one-dimensional PBL model over a sunflower field. To examine how the turbulent transfer coefficient inside tall grass canopies over a large domain represents the influence of the underlying surface on the air layer above, sensitivity tests are performed using a coupled system consisting of the NCEP Nonhydrostatic Mesoscale Model and LAPS.


  18. Design of an air traffic computer simulation system to support investigation of civil tiltrotor aircraft operations

    NASA Technical Reports Server (NTRS)

    Rogers, Ralph V.

    1992-01-01

    This research project addresses the need to provide an efficient and safe mechanism to investigate the effects and requirements of the tiltrotor aircraft's commercial operations on air transportation infrastructures, particularly air traffic control. The mechanism of choice is computer simulation. Unfortunately, the fundamental paradigms of the current air traffic control simulation models do not directly support the broad range of operational options and environments necessary to study tiltrotor operations. Modification of current air traffic simulation models to meet these requirements does not appear viable given the range and complexity of issues needing resolution. As a result, the investigation of systemic, infrastructure issues surrounding the effects of tiltrotor commercial operations requires new approaches to simulation modeling. These models should be based on perspectives and ideas closer to those associated with tiltrotor air traffic operations.

  19. Digital temperature sensor performance assessment report. [in simulated shuttle environments

    NASA Technical Reports Server (NTRS)

    Canniff, J. H.

    1974-01-01

    Performance assessment data accumulated during exposure of the digital temperature sensor to simulated shuttle flight type environments are presented. The test parameters were specifically designed to check the sensor for its: (1) ability to resolve temperature relative to the design specifications; (2) ability to maintain accuracy after interchanging the temperature probes with each electronics interface assembly; (3) stability (i.e., satisfactory operation and accuracy during and after exposure to flight environments); and (4) repeatability, or its ability to produce the same output on subsequent exposures to the identical stimulus. Equipment list, test descriptions, data summary, and conclusions are included.

  20. Increasing influence of air temperature on upper Colorado River streamflow

    NASA Astrophysics Data System (ADS)

    Woodhouse, Connie A.; Pederson, Gregory T.; Morino, Kiyomi; McAfee, Stephanie A.; McCabe, Gregory J.

    2016-03-01

    This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture can result in flow deficits of similar magnitude, but recent droughts have been amplified by warmer temperatures that exacerbate the effects of relatively modest precipitation deficits. Since 1988, a marked increase in the frequency of warm years with lower flows than expected, given precipitation, suggests continued warming temperatures will be an increasingly important influence in reducing future UCRB water supplies.

  1. Increasing influence of air temperature on upper Colorado River streamflow

    USGS Publications Warehouse

    Woodhouse, Connie A.; Pederson, Gregory T.; Morino, Kiyomi; McAfee, Stephanie A.; McCabe, Gregory

    2016-01-01

    This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture can result in flow deficits of similar magnitude, but recent droughts have been amplified by warmer temperatures that exacerbate the effects of relatively modest precipitation deficits. Since 1988, a marked increase in the frequency of warm years with lower flows than expected, given precipitation, suggests continued warming temperatures will be an increasingly important influence in reducing future UCRB water supplies.

  2. Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution

    NASA Astrophysics Data System (ADS)

    Sabbah, Rami; Kizilel, R.; Selman, J. R.; Al-Hallaj, S.

    The effectiveness of passive cooling by phase change materials (PCM) is compared with that of active (forced air) cooling. Numerical simulations were performed at different discharge rates, operating temperatures and ambient temperatures of a compact Li-ion battery pack suitable for plug-in hybrid electric vehicle (PHEV) propulsion. The results were also compared with experimental results. The PCM cooling mode uses a micro-composite graphite-PCM matrix surrounding the array of cells, while the active cooling mode uses air blown through the gaps between the cells in the same array. The results show that at stressful conditions, i.e. at high discharge rates and at high operating or ambient temperatures (for example 40-45 °C), air-cooling is not a proper thermal management system to keep the temperature of the cell in the desirable operating range without expending significant fan power. On the other hand, the passive cooling system is able to meet the operating range requirements under these same stressful conditions without the need for additional fan power.

  3. Assimilation of Goes-Derived Skin Temperature Tendencies into Mesoscale Models to Improve Forecasts of near Surface Air Temperature and Mixing Ratio

    NASA Technical Reports Server (NTRS)

    Lapenta, William M.; McNider, Richard T.; Suggs, Ron; Jedlovec, Gary; Robertson, Franklin R.

    1998-01-01

    A technique has been developed for assimilating GOES-FR skin temperature tendencies into the surface energy budget equation of a mesoscale model so that the simulated rate of temperature chance closely agrees with the satellite observations. A critical assumption of the technique is that the availability of moisture (either from the soil or vegetation) is the least known term in the model's surface energy budget. Therefore, the simulated latent heat flux, which is a function of surface moisture availability, is adjusted based upon differences between the modeled and satellite-observed skin temperature tendencies. An advantage of this technique is that satellite temperature tendencies are assimilated in an energetically consistent manner that avoids energy imbalances and surface stability problems that arise from direct assimilation of surface shelter temperatures. The fact that the rate of change of the satellite skin temperature is used rather than the absolute temperature means that sensor calibration is not as critical. An advantage of this technique for short-range forecasts (0-48 h) is that it does not require a complex land-surface formulation within the atmospheric model. As a result, the need to specify poorly known soil and vegetative characteristics is eliminated. The GOES assimilation technique has been incorporated into the PSU/NCAR MM5. Results will be presented to demonstrate the ability of the assimilation scheme to improve short- term (0-48h) simulations of near-surface air temperature and mixing ratio during the warm season for several selected cases which exhibit a variety of atmospheric and land-surface conditions. In addition, validation of terms in the simulated surface energy budget will be presented using in situ data collected at the Southern Great Plains (SGP) Cloud And Radiation Testbed (CART) site as part of the Atmospheric Radiation Measurements Program (ARM).

  4. Numerical simulations and experimental comparisons for high-speed nonequilibrium air flows

    NASA Astrophysics Data System (ADS)

    Men'shov, Igor S.; Nakamura, Yoshiaki

    2000-11-01

    A computational fluid dynamics (CFD) technique is employed to study hypersonic high-enthalpy air flows around blunt bodies with the purpose of predicting convective heat transfer on the body surface for a range of flow velocities relevant to suborbital flight of re-entry vehicles such as the Space Shuttle Orbiter (USA), and the Buran (Russia). The method uses Park's two-temperature model for the description of thermochemical nonequilibrium processes in high-temperature air and solves the full Navier-Stokes equations for a model of multicomponent reacting gas mixture in the finite volume formulation. The calculations performed in this research are intended to simulate some experiments carried out in the high-energy shock tunnels of the DLR, Germany, and the CALSPAN, USA, where the heat flux distribution over a model surface was measured at several freestream conditions related to the range of velocities mentioned above. The main emphasis is on comparing numerical and experimental results in order to verify adequacy of the heat flux data predicted by the CFD technique for suborbital flight speeds of re-entry vehicles.

  5. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

    NASA Astrophysics Data System (ADS)

    Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

    2015-11-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality.

  6. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  7. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

    PubMed Central

    Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  8. Autonomous Integrated Receive System (AIRS) requirements definition. Volume 3: Performance and simulation

    NASA Technical Reports Server (NTRS)

    Chie, C. M.; Su, Y. T.; Lindsey, W. C.; Koukos, J.

    1984-01-01

    The autonomous and integrated aspects of the operation of the AIRS (Autonomous Integrated Receive System) are discussed from a system operation point of view. The advantages of AIRS compared to the existing SSA receive chain equipment are highlighted. The three modes of AIRS operation are addressed in detail. The configurations of the AIRS are defined as a function of the operating modes and the user signal characteristics. Each AIRS configuration selection is made up of three components: the hardware, the software algorithms and the parameters used by these algorithms. A comparison between AIRS and the wide dynamics demodulation (WDD) is provided. The organization of the AIRS analytical/simulation software is described. The modeling and analysis is for simulating the performance of the PN subsystem is documented. The frequence acquisition technique using a frequency-locked loop is also documented. Doppler compensation implementation is described. The technological aspects of employing CCD's for PN acquisition are addressed.

  9. Effect of air preheat temperature and oxygen concentration on flame structure and emission

    SciTech Connect

    Bolz, S.; Gupta, A.K.

    1998-07-01

    The structure of turbulent diffusion flames with highly preheated combustion air (air preheat temperature in excess of 1,150 C) has been obtained using a specially designed regenerative combustion furnace. Propane gas was used as the fuel. Data have been obtained on the global flame features, spectral emission characteristics, spatial distribution of OH, CH and C{sub 2} species, and pollutants emission from the flames. The results have been obtained for various degrees of air preheat temperatures and O{sub 2} concentration in the air. The color of the flame was found to change from yellow to blue to bluish-green to green over the range of conditions examined. In some cases a hybrid color flame was also observed. The recorded images of the flame photographs were analyzed using color-analyzing software. The results show that thermal and chemical flame behavior strongly depends on the air preheat temperature and oxygen content in the air. The flame color was found to be bluish-green or green at very high air preheat temperatures and low-oxygen concentration. However, at high oxygen concentration the flame color was yellow. The flame volume was found to increase with increase in air-preheat temperature and decrease in oxygen concentration. The flame length showed a similar behavior. The concentrations of OH, CH and C{sub 2} increased with an increase in air preheat temperatures. These species exhibited a two-stage combustion behavior at low oxygen concentration and single stage combustion behavior at high oxygen concentration in the air. Stable flames were obtained for remarkably low equivalence ratios, which would not be possible with normal combustion air. Pollutants emission, including CO{sub 2} and NO{sub x} , was much lower with highly preheated combustion air at low O{sub 2} concentration than the normal air. The results also suggest uniform flow and flame thermal characteristics with conditioned highly preheated air. Highly preheated air combustion provides much

  10. Sampling Biases in Datasets of Historical Mean Air Temperature over Land

    NASA Astrophysics Data System (ADS)

    Wang, K.

    2014-12-01

    Global mean surface air temperature have risen by 0.74 °C over the last 100 years. However, the definition of mean surface air temperature is still a subject of debate. The most defensible definition might be the integral of the continuous temperature measurements over a day (Td0). However, for technological and historical reasons, mean temperatures (Td1) over land have been taken to be the average of the daily maximum and minimum temperature measurements. All existing principle global temperature analyses over land are primarily based on Td1. Here, I make a first quantitative assessment of the bias in the use of Td1 to estimate trends of mean air temperature using hourly air temperature observations at 5600 globally distributed weather stations from the 1970s to 2013. I find that the use of Td1 has a negligible impact on the global mean warming rate. However, the trend of Td1 has a substantial bias at regional and local scales, with a root mean square error of over 25% at 5°×5° grids. Therefore, caution should be taken when using mean air temperature datasets based on Td1 to examine spatial patterns of global warming.

  11. Estimation of Surface Air Temperature Over Central and Eastern Eurasia from MODIS Land Surface Temperature

    NASA Technical Reports Server (NTRS)

    Shen, Suhung; Leptoukh, Gregory G.

    2011-01-01

    Surface air temperature (T(sub a)) is a critical variable in the energy and water cycle of the Earth.atmosphere system and is a key input element for hydrology and land surface models. This is a preliminary study to evaluate estimation of T(sub a) from satellite remotely sensed land surface temperature (T(sub s)) by using MODIS-Terra data over two Eurasia regions: northern China and fUSSR. High correlations are observed in both regions between station-measured T(sub a) and MODIS T(sub s). The relationships between the maximum T(sub a) and daytime T(sub s) depend significantly on land cover types, but the minimum T(sub a) and nighttime T(sub s) have little dependence on the land cover types. The largest difference between maximum T(sub a) and daytime T(sub s) appears over the barren and sparsely vegetated area during the summer time. Using a linear regression method, the daily maximum T(sub a) were estimated from 1 km resolution MODIS T(sub s) under clear-sky conditions with coefficients calculated based on land cover types, while the minimum T(sub a) were estimated without considering land cover types. The uncertainty, mean absolute error (MAE), of the estimated maximum T(sub a) varies from 2.4 C over closed shrublands to 3.2 C over grasslands, and the MAE of the estimated minimum Ta is about 3.0 C.

  12. Emperor penguin body surfaces cool below air temperature.

    PubMed

    McCafferty, D J; Gilbert, C; Thierry, A-M; Currie, J; Le Maho, Y; Ancel, A

    2013-06-23

    Emperor penguins Aptenodytes forsteri are able to survive the harsh Antarctic climate because of specialized anatomical, physiological and behavioural adaptations for minimizing heat loss. Heat transfer theory predicts that metabolic heat loss in this species will mostly depend on radiative and convective cooling. To examine this, thermal imaging of emperor penguins was undertaken at the breeding colony of Pointe Géologie in Terre Adélie (66°40' S 140° 01' E), Antarctica in June 2008. During clear sky conditions, most outer surfaces of the body were colder than surrounding sub-zero air owing to radiative cooling. In these conditions, the feather surface will paradoxically gain heat by convection from surrounding air. However, owing to the low thermal conductivity of plumage any heat transfer to the skin surface will be negligible. Future thermal imaging studies are likely to yield further insights into the adaptations of this species to the Antarctic climate. PMID:23466479

  13. Emperor penguin body surfaces cool below air temperature

    PubMed Central

    McCafferty, D. J.; Gilbert, C.; Thierry, A.-M.; Currie, J.; Le Maho, Y.; Ancel, A.

    2013-01-01

    Emperor penguins Aptenodytes forsteri are able to survive the harsh Antarctic climate because of specialized anatomical, physiological and behavioural adaptations for minimizing heat loss. Heat transfer theory predicts that metabolic heat loss in this species will mostly depend on radiative and convective cooling. To examine this, thermal imaging of emperor penguins was undertaken at the breeding colony of Pointe Géologie in Terre Adélie (66°40′ S 140° 01′ E), Antarctica in June 2008. During clear sky conditions, most outer surfaces of the body were colder than surrounding sub-zero air owing to radiative cooling. In these conditions, the feather surface will paradoxically gain heat by convection from surrounding air. However, owing to the low thermal conductivity of plumage any heat transfer to the skin surface will be negligible. Future thermal imaging studies are likely to yield further insights into the adaptations of this species to the Antarctic climate. PMID:23466479

  14. Surface heat flux parameterizations and tropical Pacific sea surface temperature simulations

    SciTech Connect

    Giese, B.S. University Corp. for Atmospheric Research, Boulder, CO ); Cayan, D.R. )

    1993-04-15

    The authors report on a study of the problem of getting good model results for the sea surface temperature in the tropical Pacific ocean. The tropical Pacific is particularly important because of its size, the large areas of warm surface temperature, its impact on global atmospheric circulation, and the fact that it serves as an indicator of climatic variations. To simulate sea surface temperature it is necessary to have an energy budget which fits into a general ocean circulation model. The main input, from solar flux, is not well known in the tropical Pacific. The authors use two different models to describe the latent flux and the radiative flux at the sea surface. Parameters of concern include the relative humidity, air-sea temperature difference, latent heat formulae, and radiative heat flux. They use these parameters in their models in different ways, and compare results with measurement sets from the Tropical Pacific.

  15. Statistical modeling of urban air temperature distributions under different synoptic conditions

    NASA Astrophysics Data System (ADS)

    Beck, Christoph; Breitner, Susanne; Cyrys, Josef; Hald, Cornelius; Hartz, Uwe; Jacobeit, Jucundus; Richter, Katja; Schneider, Alexandra; Wolf, Kathrin

    2015-04-01

    Within urban areas air temperature may vary distinctly between different locations. These intra-urban air temperature variations partly reach magnitudes that are relevant with respect to human thermal comfort. Therefore and furthermore taking into account potential interrelations with other health related environmental factors (e.g. air quality) it is important to estimate spatial patterns of intra-urban air temperature distributions that may be incorporated into urban planning processes. In this contribution we present an approach to estimate spatial temperature distributions in the urban area of Augsburg (Germany) by means of statistical modeling. At 36 locations in the urban area of Augsburg air temperatures are measured with high temporal resolution (4 min.) since December 2012. These 36 locations represent different typical urban land use characteristics in terms of varying percentage coverages of different land cover categories (e.g. impervious, built-up, vegetated). Percentage coverages of these land cover categories have been extracted from different sources (Open Street Map, European Urban Atlas, Urban Morphological Zones) for regular grids of varying size (50, 100, 200 meter horizonal resolution) for the urban area of Augsburg. It is well known from numerous studies that land use characteristics have a distinct influence on air temperature and as well other climatic variables at a certain location. Therefore air temperatures at the 36 locations are modeled utilizing land use characteristics (percentage coverages of land cover categories) as predictor variables in Stepwise Multiple Regression models and in Random Forest based model approaches. After model evaluation via cross-validation appropriate statistical models are applied to gridded land use data to derive spatial urban air temperature distributions. Varying models are tested and applied for different seasons and times of the day and also for different synoptic conditions (e.g. clear and calm

  16. Accuracy comparison of spatial interpolation methods for estimation of air temperatures in South Korea

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Shim, K.; Jung, M.; Kim, S.

    2013-12-01

    Because of complex terrain, micro- as well as meso-climate variability is extreme by locations in Korea. In particular, air temperature of agricultural fields are influenced by topographic features of the surroundings making accurate interpolation of regional meteorological data from point-measured data. This study was conducted to compare accuracy of a spatial interpolation method to estimate air temperature in Korean Peninsula with the rugged terrains in South Korea. Four spatial interpolation methods including Inverse Distance Weighting (IDW), Spline, Kriging and Cokriging were tested to estimate monthly air temperature of unobserved stations. Monthly measured data sets (minimum and maximum air temperature) from 456 automatic weather station (AWS) locations in South Korea were used to generate the gridded air temperature surface. Result of cross validation showed that using Exponential theoretical model produced a lower root mean square error (RMSE) than using Gaussian theoretical model in case of Kriging and Cokriging and Spline produced the lowest RMSE of spatial interpolation methods in both maximum and minimum air temperature estimation. In conclusion, Spline showed the best accuracy among the methods, but further experiments which reflect topography effects such as temperature lapse rate are necessary to improve the prediction.

  17. Preliminary verification of instantaneous air temperature estimation for clear sky conditions based on SEBAL

    NASA Astrophysics Data System (ADS)

    Zhu, Shanyou; Zhou, Chuxuan; Zhang, Guixin; Zhang, Hailong; Hua, Junwei

    2016-03-01

    Spatially distributed near surface air temperature at the height of 2 m is an important input parameter for the land surface models. It is of great significance in both theoretical research and practical applications to retrieve instantaneous air temperature data from remote sensing observations. An approach based on Surface Energy Balance Algorithm for Land (SEBAL) to retrieve air temperature under clear sky conditions is presented. Taking the meteorological measurement data at one station as the reference and remotely sensed data as the model input, the research estimates the air temperature by using an iterative computation. The method was applied to the area of Jiangsu province for nine scenes by using MODIS data products, as well as part of Fujian province, China based on four scenes of Landsat 8 imagery. Comparing the air temperature estimated from the proposed method with that of the meteorological station measurement, results show that the root mean square error is 1.7 and 2.6 °C at 1000 and 30 m spatial resolution respectively. Sensitivity analysis of influencing factors reveals that land surface temperature is the most sensitive to the estimation precision. Research results indicate that the method has great potentiality to be used to estimate instantaneous air temperature distribution under clear sky conditions.

  18. 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 ...

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

    NASA Technical Reports Server (NTRS)

    Hansen, C Frederick; Heims, Steve P

    1958-01-01

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

  20. Air oxidation of Zircaloy-4 in the 600-1000 °C temperature range: Modeling for ASTEC code application

    NASA Astrophysics Data System (ADS)

    Coindreau, O.; Duriez, C.; Ederli, S.

    2010-10-01

    Progress in the treatment of air oxidation of zirconium in severe accident (SA) codes are required for a reliable analysis of severe accidents involving air ingress. Air oxidation of zirconium can actually lead to accelerated core degradation and increased fission product release, especially for the highly-radiotoxic ruthenium. This paper presents a model to simulate air oxidation kinetics of Zircaloy-4 in the 600-1000 °C temperature range. It is based on available experimental data, including separate-effect experiments performed at IRSN and at Forschungszentrum Karlsruhe. The kinetic transition, named "breakaway", from a diffusion-controlled regime to an accelerated oxidation is taken into account in the modeling via a critical mass gain parameter. The progressive propagation of the locally initiated breakaway is modeled by a linear increase in oxidation rate with time. Finally, when breakaway propagation is completed, the oxidation rate stabilizes and the kinetics is modeled by a linear law. This new modeling is integrated in the severe accident code ASTEC, jointly developed by IRSN and GRS. Model predictions and experimental data from thermogravimetric results show good agreement for different air flow rates and for slow temperature transient conditions.

  1. High temperature dilatometry of simulated oxide nuclear fuel

    NASA Astrophysics Data System (ADS)

    Tenishev, A. V.; Baranov, V. G.; Kuzmin, R. S.; Pokrovskiy, S. A.

    2016-04-01

    High temperature dilatometry of model systems based on uranium dioxide with additives of burnable neutron absorbers both as Gd2O3 and as AlGdO3, and fission products simulators (FPS) was performed. It shown that in some cases instead of high temperature samples shrinkage there is a sharp transition to the expansion, which is associated with an increase of the samples volume due to the formation of liquid phases. The beginning of a complex composition eutectic melting starts at temperatures from 1950 to 2250 °C in the uranium dioxide samples containing significant amounts of Al, Gd, and FPS. Thus, in the analysis of oxide nuclear fuel behavior at high temperatures should be considered that the formation of liquid phases is possible at a temperature of 1000 °C lower than a melting point of pure stoichiometric uranium dioxide if its initial composition became more complex.

  2. Ultraviolet Laser Raman Scattering for Temperature Measurement in Atmospheric Air Microdischarges

    NASA Astrophysics Data System (ADS)

    Caplinger, James; Adams, Steven; Williamson, James; Clark, Jerry

    2011-10-01

    Vibrational Raman scattering for temperature measurement within a dc microdischarge in atmospheric pressure air has been investigated using a pulsed ultraviolet laser. The Raman signal analysis method involved monitoring Q-branch signals originating from multiple N2(X) vibrational states populated in the microdischarge. The translational temperature of N2(X) in the microdischarge was calculated using the total Raman signal intensity calibrated with room temperature air. Also, the distribution of Q-branch intensities among vibrational states allowed for direct measurement of the vibrational temperature of N2(X). Raman scattering results are compared to passive optical emission spectral analyses of the N2 second positive system from which the rotational and vibrational temperatures of the N2(C) excited state were also calculated. A comparison of the N2(X) and N2(C) temperatures derived from Raman scattering and emission spectroscopy, respectively, is presented. This work was supported by the Air Force Office of Scientific Research.

  3. The characteristics of high temperature air combustion and its practical application to high performance industrial furnace

    SciTech Connect

    Sugiyama, Shunichi; Suzukawa, Yutaka; Hino, Yoshimichi

    1999-07-01

    An experimental regenerative continuous slab reheat furnace was used for the data acquisition of high temperature air combustion. Obtainable preheated air temperature, gas temperature distribution of combustion field, NOx concentration in waste gas, heating pattern, furnace height etc were studied for this purpose. Main results were (1) preheated air temperature close to furnace temperature can be obtained, (2) gas temperature distribution is relatively uniform in main combustion field, (3) NOx concentration in waste gas is significantly reduced, (4) there exists the appropriate combustion capacity of a burner for every furnace width, (5) the optimum furnace height for regenerative continuous slab reheat furnace from the thermal efficiency point of view is lower than the convention one by about 0.5m.

  4. Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen

    SciTech Connect

    Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M; Benedict, L; Hau-Riege, S; Langdon, A; London, R

    2008-02-14

    The temperature equilibration rate in dense hydrogen (for both T{sub i} > T{sub e} and T{sub i} < T{sub e}) has been calculated with large-scale molecular dynamics simulations for temperatures between 10 and 300 eV and densities between 10{sup 20}/cc to 10{sup 24}/cc. Careful attention has been devoted to convergence of the simulations, including the role of semiclassical potentials. We find that for Coulomb logarithms L {approx}> 1, Brown-Preston-Singleton [Brown et al., Phys. Rep. 410, 237 (2005)] with the sub-leading corrections and the fit of Gericke-Murillo-Schlanges [Gericke et al., PRE 65, 036418 (2003)] to the T-matrix evaluation of the collision operator, agrees with the MD data to within the error bars of the simulation. For more strongly-coupled plasmas where L {approx}< 1, our numerical results are consistent with the fit of Gericke-Murillo-Schlanges.

  5. Effect of increasing urban albedo on meteorology and air quality of Montreal (Canada) - Episodic simulation of heat wave in 2005

    NASA Astrophysics Data System (ADS)

    Touchaei, Ali G.; Akbari, Hashem; Tessum, Christopher W.

    2016-05-01

    Increasing albedo is an effective strategy to mitigate urban air temperature in different climates. Using reflective urban surfaces decreases the air temperature, which potentially reduces the rate of generation of smog. However, for implementing the albedo enhancement, complicated interactions between air, moisture, aerosols, and other gaseous contaminant in the atmosphere should be considered. We used WRF-CHEM to investigate the effect of increasing albedo in Montreal, Canada, during a heat wave period (July 10th through July 12th, 2005) on air quality and urban climate. The reflectivity of roofs, walls, and roads are increased from 0.2 to 0.65, 0.6, and 0.45, respectively. Air temperature at 2-m elevation is decreased during all hours in the simulation period and the maximum reduction is about 1 °C on each day (Tmax is reduced by about 0.7 °C) The concentration of two regulated pollutants -ozone (O3) and fine particulate matters (PM2.5) - is calculated at a height of 5-m above the ground. The maximum decrease in 8-h averaged ozone concentration is about 3% (∼0.2 ppbv). 24-h averaged PM2.5 concentration decreases by 1.8 μg/m3. This relatively small change in concentration of pollutants is related to the decrease in planetary boundary layer height caused by increasing the albedo. Additionally, the combined effect of decreased solar heat gain by building surfaces and decreased air temperature reduces the energy consumption of HVAC systems by 2% (∼0.1 W/m2), which exacerbates the positive effect of the albedo enhancement on the air quality.

  6. Effect of increasing urban albedo on meteorology and air quality of Montreal (Canada) - Episodic simulation of heat wave in 2005

    NASA Astrophysics Data System (ADS)

    Touchaei, Ali G.; Akbari, Hashem; Tessum, Christopher W.

    2016-05-01

    Increasing albedo is an effective strategy to mitigate urban air temperature in different climates. Using reflective urban surfaces decreases the air temperature, which potentially reduces the rate of generation of smog. However, for implementing the albedo enhancement, complicated interactions between air, moisture, aerosols, and other gaseous contaminant in the atmosphere should be considered. We used WRF-CHEM to investigate the effect of increasing albedo in Montreal, Canada, during a heat wave period (July 10th through July 12th, 2005) on air quality and urban climate. The reflectivity of roofs, walls, and roads are increased from 0.2 to 0.65, 0.6, and 0.45, respectively. Air temperature at 2-m elevation is decreased during all hours in the simulation period and the maximum reduction is about 1 °C on each day (Tmax is reduced by about 0.7 °C) The concentration of two regulated pollutants -ozone (O3) and fine particulate matters (PM2.5) - is calculated at a height of 5-m above the ground. The maximum decrease in 8-h averaged ozone concentration is about 3% (∼0.2 ppbv). 24-h averaged PM2.5 concentration decreases by 1.8 μg/m3. This relatively small change in concentration of pollutants is related to the decrease in planetary boundary layer height caused by increasing the albedo. Additionally, the combined effect of decreased solar heat gain by building surfaces and decreased air temperature reduces the energy consumption of HVAC systems by 2% (∼0.1 W/m2), which exacerbates the positive effect of the albedo enhancement on the air quality.

  7. Reservoir Simulations of Low-Temperature Geothermal Reservoirs

    NASA Astrophysics Data System (ADS)

    Bedre, Madhur Ganesh

    The eastern United States generally has lower temperature gradients than the western United States. However, West Virginia, in particular, has higher temperature gradients compared to other eastern states. A recent study at Southern Methodist University by Blackwell et al. has shown the presence of a hot spot in the eastern part of West Virginia with temperatures reaching 150°C at a depth of between 4.5 and 5 km. This thesis work examines similar reservoirs at a depth of around 5 km resembling the geology of West Virginia, USA. The temperature gradients used are in accordance with the SMU study. In order to assess the effects of geothermal reservoir conditions on the lifetime of a low-temperature geothermal system, a sensitivity analysis study was performed on following seven natural and human-controlled parameters within a geothermal reservoir: reservoir temperature, injection fluid temperature, injection flow rate, porosity, rock thermal conductivity, water loss (%) and well spacing. This sensitivity analysis is completed by using ‘One factor at a time method (OFAT)’ and ‘Plackett-Burman design’ methods. The data used for this study was obtained by carrying out the reservoir simulations using TOUGH2 simulator. The second part of this work is to create a database of thermal potential and time-dependant reservoir conditions for low-temperature geothermal reservoirs by studying a number of possible scenarios. Variations in the parameters identified in sensitivity analysis study are used to expand the scope of database. Main results include the thermal potential of reservoir, pressure and temperature profile of the reservoir over its operational life (30 years for this study), the plant capacity and required pumping power. The results of this database will help the supply curves calculations for low-temperature geothermal reservoirs in the United States, which is the long term goal of the work being done by the geothermal research group under Dr. Anderson at

  8. 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.

  9. Biodiesel and Cold Temperature Effect on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  10. Biodiesel and Cold Temperature Effects on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  11. Air stability of low-temperature dehydrogenation of Pd-decorated Mg blades.

    PubMed

    Liu, Yu; Wang, Gwo-Ching

    2012-01-20

    We demonstrated that Pd-decorated Mg blades are air-stable for hydrogen storage with a low desorption temperature of 373 K. Pd-catalyst-decorated Mg blades were prepared by 64° oblique incident angle thermal deposition on a rotatable substrate with the rotation axis perpendicular to the substrate. The hydrogen desorption from Pd-decorated Mg blades was performed and recorded by temperature-programmed desorption (TPD) for repeated hydrogenation–dehydrogenation cycles. The near-surface structural and compositional changes were characterized in situ by reflection high energy electron diffraction (RHEED). The Mg blades were intentionally exposed to air at elevated temperatures (333 or 358 K) between certain cycles. It was found that the degradation of the storage capacity was affected weakly by the air exposure at moderate temperatures. The kinetics of the hydrogen desorption was sensitive to air exposure but recoverable through a replenishment of fresh catalyst Pd on the surface of the oxidized Mg blades. PMID:22166731

  12. Transport properties of high-temperature air in a magnetic field

    SciTech Connect

    Bruno, D.; Capitelli, M.; Catalfamo, C.; Giordano, D.

    2011-01-15

    Transport properties of equilibrium air plasmas in a magnetic field are calculated with the Chapman-Enskog method. The range considered for the temperature is [50-50 000] K and for the magnetic induction is [0-300] T.

  13. Lidar temperature profiling - Performance simulations of Mason's method

    NASA Technical Reports Server (NTRS)

    Schwemmer, G. K.; Wilkerson, T. D.

    1979-01-01

    In Mason's method (1975) atmospheric temperatures are inferred from a measure of the Boltzmann distribution of rotational states in one of the vibrational bands of O2. Differential absorption is measured using three tunable, narrowband pulse lasers. The outputs of two are tuned to wavelengths at the centers of absorption lines at either end of a particular branch in the band; the third wavelength is in a region of no absorption. The temperature-altitude profile can be calculated from the ratio of the two line absorption coefficients plus a priori knowledge of the line parameters. In the present paper, computer simulations of various lidar configurations are made, using different line pairs in the atmospheric bands of O2 (approximately 630, 690, and 760 nm). Simulated results are presented for temperature profiles measured from a Space Shuttle lidar.

  14. Apparatus and method for generating large mass flow of high temperature air at hypersonic speeds

    NASA Technical Reports Server (NTRS)

    Sabol, A. P.; Stewart, R. B. (Inventor)

    1973-01-01

    High temperature, high mass air flow and a high Reynolds number test air flow in the Mach number 8-10 regime of adequate test flow duration is attained by pressurizing a ceramic-lined storage tank with air to a pressure of about 100 to 200 atmospheres. The air is heated to temperatures of 7,000 to 8,000 R prior to introduction into the tank by passing the air over an electric arc heater means. The air cools to 5,500 to 6,000 R while in the tank. A decomposable gas such as nitrous oxide or a combustible gas such as propane is injected into the tank after pressurization and the heated pressurized air in the tank is rapidly released through a Mach number 8-10 nozzle. The injected gas medium upon contact with the heated pressurized air effects an exothermic reaction which maintains the pressure and temperature of the pressurized air during the rapid release.

  15. Improving forecast skill by assimilation of quality-controlled AIRS temperature retrievals under partially cloudy conditions

    NASA Astrophysics Data System (ADS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Liu, E.; Riishojgaard, L. P.; Terry, J.; Jusem, J. C.

    2008-04-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite is now recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  16. Improving Forecast Skill by Assimilation of Quality-controlled AIRS Temperature Retrievals under Partially Cloudy Conditions

    NASA Technical Reports Server (NTRS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Riishojgaard, L.; Liu, E.; Terry, J.; Jusem, J. C.

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite has been long recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  17. 40 CFR 86.162-03 - Approval of alternative air conditioning test simulations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... initiative, the Administrator will approve a simulation of the environmental cell for air conditioning test... approvals will be granted, the Administrator will consider data showing how well the simulation matches environmental cell test data for the range of vehicles to be covered by the simulation including items such...

  18. 40 CFR 86.162-03 - Approval of alternative air conditioning test simulations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... initiative, the Administrator will approve a simulation of the environmental cell for air conditioning test... approvals will be granted, the Administrator will consider data showing how well the simulation matches environmental cell test data for the range of vehicles to be covered by the simulation including items such...

  19. Simulation of soil temperature dynamics with models using different concepts.

    PubMed

    Sándor, Renáta; Fodor, Nándor

    2012-01-01

    This paper presents two soil temperature models with empirical and mechanistic concepts. At the test site (calcaric arenosol), meteorological parameters as well as soil moisture content and temperature at 5 different depths were measured in an experiment with 8 parcels realizing the combinations of the fertilized, nonfertilized, irrigated, nonirrigated treatments in two replicates. Leaf area dynamics was also monitored. Soil temperature was calculated with the original and a modified version of CERES as well as with the HYDRUS-1D model. The simulated soil temperature values were compared to the observed ones. The vegetation reduced both the average soil temperature and its diurnal amplitude; therefore, considering the leaf area dynamics is important in modeling. The models underestimated the actual soil temperature and overestimated the temperature oscillation within the winter period. All models failed to account for the insulation effect of snow cover. The modified CERES provided explicitly more accurate soil temperature values than the original one. Though HYDRUS-1D provided more accurate soil temperature estimations, its superiority to CERES is not unequivocal as it requires more detailed inputs. PMID:22792047

  20. Simulation of Soil Temperature Dynamics with Models Using Different Concepts

    PubMed Central

    Sándor, Renáta; Fodor, Nándor

    2012-01-01

    This paper presents two soil temperature models with empirical and mechanistic concepts. At the test site (calcaric arenosol), meteorological parameters as well as soil moisture content and temperature at 5 different depths were measured in an experiment with 8 parcels realizing the combinations of the fertilized, nonfertilized, irrigated, nonirrigated treatments in two replicates. Leaf area dynamics was also monitored. Soil temperature was calculated with the original and a modified version of CERES as well as with the HYDRUS-1D model. The simulated soil temperature values were compared to the observed ones. The vegetation reduced both the average soil temperature and its diurnal amplitude; therefore, considering the leaf area dynamics is important in modeling. The models underestimated the actual soil temperature and overestimated the temperature oscillation within the winter period. All models failed to account for the insulation effect of snow cover. The modified CERES provided explicitly more accurate soil temperature values than the original one. Though HYDRUS-1D provided more accurate soil temperature estimations, its superiority to CERES is not unequivocal as it requires more detailed inputs. PMID:22792047

  1. Direct Numerical Simulation of Air Layer Drag Reduction over a Backward-facing Step

    NASA Astrophysics Data System (ADS)

    Kim, Dokyun; Moin, Parviz

    2010-11-01

    Direct Numerical Simulation (DNS) of two-phase flow is performed to investigate the air layer drag reduction (ALDR) phenomenon in turbulent flow over a backward-facing step. In their experimental study, Elbing et al. (JFM, 2008) have observed a stable air layer on an entire flat plate if air is injected beyond the critical air-flow rate. In the present study, air is injected at the step on the wall into turbulent water flow for ALDR. The Reynolds and Weber numbers based on the water properties and step height are 22,800 and 560, respectively. An inlet section length before the step is 3h and the post expansion length is 30h, where h is the step height. The total number of grid points is about 271 million for DNS. The level set method is used to track the phase interface and the structured-mesh finite volume solver is used with an efficient algorithm for two-phase DNS. Two cases with different air-flow rates are performed to investigate the mechanism and stability of air layer. For high air-flow rate, the stable air layer is formed on the plate and more than 90% drag reduction is obtained. In the case of low air-flow rate, the air layer breaks up and ALDR is not achieved. The parameters governing the stability of air layer from the numerical simulations is also consistent with the results of stability analysis.

  2. Assessing the Potential of the AIRS Retrieved Surface Temperature for 6-Hour Average Temperature Forecast in River Forecast Centers

    NASA Astrophysics Data System (ADS)

    Ding, F.; Theobald, M.; Vollmer, B.; Savtchenko, A. K.; Hearty, T. J.; Esfandiari, A. E.

    2012-12-01

    Producing timely and accurate water forecast and information is the mission of National Weather Service River Forecast Centers (NWS RFCs) of National Oceanic and Atmospheric Administration (NOAA). The river forecast system in RFCs requires average surface temperature in the fixed 6-hour period 000-0600, 0600-1200, 1200-1800, and 1200-0000 UTC. The current logic of RFC temperature forecast relies on ingest of point values of daytime maximum and nighttime minimum temperature. Meanwhile, the mean temperature for the 6-hour period is estimated from a weighted average of daytime maximum and nighttime minimum temperature. The Atmospheric Infrared Sounder (AIRS) in the first high spectral resolution infrared sounder on board the Aqua satellite which was launched in May 2002 and follows a Sun-synchronous polar orbit. It is aimed to produce high resolution atmospheric profile and surface atmospheric parameters. As Aqua crosses the equator at about 1330 and 0130 local time, the AIRS retrieved surface temperature may represent daytime maximum and nighttime minimum value. Comparing to point observation from surface weather stations which are often sparse over the less-populated area and are unevenly distributed, satellite may obtain better area averaged observation. This test study assesses the potential of using AIRS retrieved surface temperature to forecast 6-hour average temperature for NWS RFCs. The California Nevada RFC is selected due to the poor coverage of surface observation in the mountainous region and spring snow melting. The study focuses on the March to May spring season when water from snowpack melting often plays important role in flood. AIRS retrieved temperature and surface weather station data set will be used to derive statistical weighting coefficient for 6-hour average temperature forecast. The resulting forecast biases and errors will be the main indicators of the potential usage. All study results will be presented in the meeting.

  3. Numerical simulation of air flow in a model of lungs with mouth cavity

    NASA Astrophysics Data System (ADS)

    Elcner, Jakub; Lizal, Frantisek; Jedelsky, Jan; Jicha, Miroslav

    2012-04-01

    The air flow in a realistic geometry of human lung is simulated with computational flow dynamics approach as stationary inspiration. Geometry used for the simulation includes oral cavity, larynx, trachea and bronchial tree up to the seventh generation of branching. Unsteady RANS approach was used for the air flow simulation. Velocities corresponding to 15, 30 and 60 litres/min of flow rate were set as boundary conditions at the inlet to the model. These flow rates are frequently used as a representation of typical human activities. Character of air flow in the model for these different flow rates is discussed with respect to future investigation of particle deposition.

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

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.

    1986-01-01

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

  5. Repeat temperature measurements in boreholes from northwestern Utah link ground and air temperature changes at the decadal time scale

    NASA Astrophysics Data System (ADS)

    Davis, Michael G.; Harris, Robert N.; Chapman, David S.

    2010-05-01

    Borehole temperature profiles provide a record of ground surface temperature (GST) change at the decadal to centennial time scale. GST histories reconstructed from boreholes are particularly useful in climate reconstruction if changes in GST and surface air temperature (SAT) are effectively coupled at decadal and longer time periods and it can be shown that borehole temperatures respond faithfully to surface temperature changes. We test these assumptions using three boreholes in northwestern Utah that have been repeatedly logged for temperature over a time span of 29 years. We report 13 temperature-depth logs at the Emigrant Pass Observatory borehole GC-1, eight at borehole SI-1 and five at borehole DM-1, acquired between 1978 and 2007. Systematic subsurface temperature changes of up to 0.6°C are observed over this time span in the upper sections of the boreholes; below approximately 100 m any temperature transients are within observational noise. We difference the temperature logs to highlight subsurface transients and to remove any ambiguity resulting from steady state source of curvature. Synthetic temperature profiles computed from SAT data at nearby meteorological stations reproduce both the amplitude and pattern of the transient temperature observations, fitting the observations to within 0.03°C or better. This observational confirmation of the strong coupling between surface temperature change and borehole temperature transients lends further support to the use of borehole temperatures to complement SAT and multiproxy reconstructions of climate change.

  6. Air quality and temperature effects on exercise-induced bronchoconstriction.

    PubMed

    Rundell, Kenneth W; Anderson, Sandra D; Sue-Chu, Malcolm; Bougault, Valerie; Boulet, Louis-Philippe

    2015-04-01

    Exercise-induced bronchoconstriction (EIB) is exaggerated constriction of the airways usually soon after cessation of exercise. This is most often a response to airway dehydration in the presence of airway inflammation in a person with a responsive bronchial smooth muscle. Severity is related to water content of inspired air and level of ventilation achieved and sustained. Repetitive hyperpnea of dry air during training is associated with airway inflammatory changes and remodeling. A response during exercise that is related to pollution or allergen is considered EIB. Ozone and particulate matter are the most widespread pollutants of concern for the exercising population; chronic exposure can lead to new-onset asthma and EIB. Freshly generated emissions particulate matter less than 100 nm is most harmful. Evidence for acute and long-term effects from exercise while inhaling high levels of ozone and/or particulate matter exists. Much evidence supports a relationship between development of airway disorders and exercise in the chlorinated pool. Swimmers typically do not respond in the pool; however, a large percentage responds to a dry air exercise challenge. Studies support oxidative stress mediated pathology for pollutants and a more severe acute response occurs in the asthmatic. Winter sport athletes and swimmers have a higher prevalence of EIB, asthma and airway remodeling than other athletes and the general population. Because of fossil fuel powered ice resurfacers in ice rinks, ice rink athletes have shown high rates of EIB and asthma. For the athlete training in the urban environment, training during low traffic hours and in low traffic areas is suggested. PMID:25880506

  7. Synthesizing SMOS Zero-Baselines with Aquarius Brightness Temperature Simulator

    NASA Technical Reports Server (NTRS)

    Colliander, A.; Dinnat, E.; Le Vine, D.; Kainulainen, J.

    2012-01-01

    SMOS [1] and Aquarius [2] are ESA and NASA missions, respectively, to make L-band measurements from the Low Earth Orbit. SMOS makes passive measurements whereas Aquarius measures both passive and active. SMOS was launched in November 2009 and Aquarius in June 2011.The scientific objectives of the missions are overlapping: both missions aim at mapping the global Sea Surface Salinity (SSS). Additionally, SMOS mission produces soil moisture product (however, Aquarius data will eventually be used for retrieving soil moisture too). The consistency of the brightness temperature observations made by the two instruments is essential for long-term studies of SSS and soil moisture. For resolving the consistency, the calibration of the instruments is the key. The basis of the SMOS brightness temperature level is the measurements performed with the so-called zero-baselines [3]; SMOS employs an interferometric measurement technique which forms a brightness temperature image from several baselines constructed by combination of multiple receivers in an array; zero-length baseline defines the overall brightness temperature level. The basis of the Aquarius brightness temperature level is resolved from the brightness temperature simulator combined with ancillary data such as antenna patterns and environmental models [4]. Consistency between the SMOS zero-baseline measurements and the simulator output would provide a robust basis for establishing the overall comparability of the missions.

  8. The temperature of inspired air influences respiratory water loss in young lambs.

    PubMed

    Riesenfeld, T; Hammarlund, K; Norsted, T; Sedin, G

    1994-01-01

    The temperature of inspired air influences respiratory water loss (RWL) in young lambs. Water loss from the airways, oxygen consumption and carbon dioxide production were measured using an open flow-through system with a mass spectrometer, specially equipped with a water channel, for gas analysis. Measurements were made in 9 newborn lambs at 3 different inspired air temperatures keeping all other environmental factors stable, including the ambient air temperature. The water content of the inspired air was also kept constant. RWL was found to be 9.9 +/- 3.9 (SD) mg/kg/min when the temperature of the inspired air was 30 degrees C and its humidity 30%. At 40 degrees C this loss increased to 11.5 +/- 3.6 mg/kg/min, and at about 60 degrees C it increased further to 26.0 +/- 8.2 mg/kg/min. The oxygen consumption was 10.0 +/- 0.8 (SD) ml/kg/min at 30 degrees C and 10.4 +/- 2.0 ml/kg/min at 60 degrees C, a change which is not significant. Thus RWL is influenced by the temperature of the inspired air, with greater loss at higher temperatures. PMID:8054401

  9. Near-surface air temperature and snow skin temperature comparison from CREST-SAFE station data with MODIS land surface temperature data

    NASA Astrophysics Data System (ADS)

    Pérez Díaz, C. L.; Lakhankar, T.; Romanov, P.; Muñoz, J.; Khanbilvardi, R.; Yu, Y.

    2015-08-01

    Land Surface Temperature (LST) is a key variable (commonly studied to understand the hydrological cycle) that helps drive the energy balance and water exchange between the Earth's surface and its atmosphere. One observable constituent of much importance in the land surface water balance model is snow. Snow cover plays a critical role in the regional to global scale hydrological cycle because rain-on-snow with warm air temperatures accelerates rapid snow-melt, which is responsible for the majority of the spring floods. Accurate information on near-surface air temperature (T-air) and snow skin temperature (T-skin) helps us comprehend the energy and water balances in the Earth's hydrological cycle. T-skin is critical in estimating latent and sensible heat fluxes over snow covered areas because incoming and outgoing radiation fluxes from the snow mass and the air temperature above make it different from the average snowpack temperature. This study investigates the correlation between MODerate resolution Imaging Spectroradiometer (MODIS) LST data and observed T-air and T-skin data from NOAA-CREST-Snow Analysis and Field Experiment (CREST-SAFE) for the winters of 2013 and 2014. LST satellite validation is imperative because high-latitude regions are significantly affected by climate warming and there is a need to aid existing meteorological station networks with the spatially continuous measurements provided by satellites. Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data. Additional findings show that there is a negative trend demonstrating that the air minus snow skin temperature difference is inversely proportional to cloud cover. To a lesser extent, it will be examined whether the surface properties at the site are representative for the LST properties within the instrument field of view.

  10. Peptide Bond Isomerization in High-Temperature Simulations.

    PubMed

    Neale, Chris; Pomès, Régis; García, Angel E

    2016-04-12

    Force fields for molecular simulation are generally optimized to model macromolecules such as proteins at ambient temperature and pressure. Nevertheless, elevated temperatures are frequently used to enhance conformational sampling, either during system setup or as a component of an advanced sampling technique such as temperature replica exchange. Because macromolecular force fields are now put upon to simulate temperatures and time scales that greatly exceed their original design specifications, it is appropriate to re-evaluate whether these force fields are up to the task. Here, we quantify the rates of peptide bond isomerization in high-temperature simulations of three octameric peptides and a small fast-folding protein. We show that peptide octamers with and without proline residues undergo cis/trans isomerization every 1-5 ns at 800 K with three classical atomistic force fields (AMBER99SB-ILDN, CHARMM22/CMAP, and OPLS-AA/L). On the low microsecond time scale, these force fields permit isomerization of nonprolyl peptide bonds at temperatures ≥500 K, and the CHARMM22/CMAP force field permits isomerization of prolyl peptide bonds ≥400 K. Moreover, the OPLS-AA/L force field allows chiral inversion about the Cα atom at 800 K. Finally, we show that temperature replica exchange permits cis peptide bonds developed at 540 K to subsequently migrate back to the 300 K ensemble, where cis peptide bonds are present in 2 ± 1% of the population of Trp-cage TC5b, including up to 4% of its folded state. Further work is required to assess the accuracy of cis/trans isomerization in the current generation of protein force fields. PMID:26866899

  11. A Comprehensive Analysis of AIRS Near Surface Air Temperature and Water Vapor Over Land and Tropical Ocean

    NASA Astrophysics Data System (ADS)

    Dang, H. V. T.; Lambrigtsen, B.; Manning, E. M.; Fetzer, E. J.; Wong, S.; Teixeira, J.

    2015-12-01

    Version 6 (V6) of the Atmospheric Infrared Sounder's (AIRS) combined infrared and microwave (IR+MW) retrieval of near surface air temperature (NSAT) and water vapor (NSWV) is validated over the United States with the densely populated MESONET data. MESONET data is a collection of surface/near surface meteorological data from many federal and state agencies. The ones used for this analysis are measured from instruments maintained by the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the Interagency Remote Automatic Weather Stations (RAWS), resulting in a little more than four thousand locations throughout the US. Over the Tropical oceans, NSAT and NSWV are compared to a network of moored buoys from the Tropical Atmosphere Ocean/Triangle Trans-Ocean Buoy Network (TAO/TRITON), and the Pilot Research Moored Array in the Tropical Atlantic (PIRATA). With the analysis of AIRS surface and near surface products over ocean, we glean information on how retrieval of NSAT and NSWV over land can be improved and why it needs some adjustments. We also compare AIRS initial guess of near surface products that are trained on fifty days of ECMWF along with AIRS calibrated radiances, to ECMWF analysis data. The comparison is done to show the differing characteristics of AIRS initial guesses from ECMWF.

  12. Surface air temperature anomalies for the Northern Hemisphere: The Russian dataset

    SciTech Connect

    Robock, A.; Borzenkova, I.I.; Gurza, G.V.; Vinnikov, K.Ya.

    1988-03-01

    The existence of a Russian surface temperature dataset became known to Western scientists when Budyko (1969) showed the secular variation of temperature and direct radiation for the Northern Hemisphere. His results were derived from maps of monthly mean surface air temperature anomalies compiled at the Main Geophysical Observatory. These maps covered the period 1881 to 1960 and were prepared for the purpose of monthly and seasonal forecasting, with a goal of finding patterns in monthly departures from normal temperatures.

  13. Duration study for heating and air-conditioning design temperatures

    SciTech Connect

    Snelling, H.J.

    1985-01-01

    Recently, abnormally cold winters and hot summers have generated interest in the duration of time that design temperature values have been equaled or exceeded. ETAC's Engineering Meteorology Section did a pilot study to examine temperature records for several military installations and give some insight into durations that may occur. The authors chose sites to represent different climatic regimes. For each site, the authors generated statistics on the number of occurrences of durations of one, two, three ... up to eight hours for each of the design temperature values (1%, 2 1/2%, and 5% temperatures for the summer months; 99% and 97 1/2% for winter months). The authors also made a study of the longest duration of each design value. The authors used the latest available 15 consecutive years of temperature data for all sites. The authors also made a comparison of data for the 15-year period of record (POR) versus data for the total available POR for some of the sites. Results were inconclusive and indicate that more study is needed.

  14. Detection and Attribution of the surface air temperature during last millennium

    NASA Astrophysics Data System (ADS)

    Peng, Dongdong; Zhou, Tianjun; Man, Wenmin

    2016-04-01

    An optimal detection method was employed to compare the reconstructed and model-simulated changes of surface air temperature during last millennium. Model simulations are from CESM1-CAM5, which include 28-member ensembles in total, i.e., 5-member ensembles volcanic forcing runs, 4-member ensembles solar forcing runs, 3-member ensembles forcing runs for land use, orbital, greenhouse gases, and 10-member ensembles runs from combined 5 individual external forcing. Analyses were conducted from hemispherical to continental scale. Results show that combined effect of all the external forcings can be detected for both Northern and Southern Hemisphere, and for the continent of Europe, Arctic and Antarctic. The influence of volcanic eruption and solar activity can be detected for all the hemispheres and nearly all the continents of North Hemisphere. Land use forcing can be detected for all the continents of Northern Hemisphere, but only detected for one continent of Southern Hemisphere, i.e., South America. The orbital forcing is detected for all the continents of Northern Hemisphere, but not detected for the Northern Hemisphere as whole. Influence of greenhouse gases can rarely be detected from hemispherical to continental scale.

  15. BOREAS RSS-17 Stem, Soil, and Air Temperature Data

    NASA Technical Reports Server (NTRS)

    Zimmerman, Reiner; McDonald, Kyle C.; Way, JoBea; Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS RSS-17 team collected several data sets in support of its research in monitoring and analyzing environmental and phenological states using radar data. This data set consists of tree bole and soil temperature measurements from various BOREAS flux tower sites. Temperatures were measured with thermistors implanted in the hydroconductive tissue of the trunks of several trees at each site and at various depths in the soil. Data were stored on a data logger at intervals of either 1 or 2 hours. The majority of the data were acquired between early 1994 and early 1995. The primary product of this data set is the diurnal stem temperature measurements acquired for selected trees at five BOREAS tower sites. The data are provided in tabular ASCII format. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  16. Data Assimilation Experiments Using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2009-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains a number of significant improvements over Version 4. Two very significant improvements are described briefly below. 1) The AIRS Science Team Radiative Transfer Algorithm (RTA) has now been upgraded to accurately account for effects of non-local thermodynamic equilibrium on the AIRS observations. This allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval algorithm during both day and night. Following theoretical considerations, tropospheric temperature profile information is obtained almost exclusively from clear column radiances in the 4.3 micron CO2 band in the AIRS Version 5 temperature profile retrieval step. These clear column radiances are a derived product that are indicative of radiances AIRS channels would have seen if the field of view were completely clear. Clear column radiances for all channels are determined using tropospheric sounding 15 micron CO2 observations. This approach allows for the generation of accurate values of clear column radiances and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel clear column radiances. These error estimates are used for quality control of the retrieved products. Based on error estimate thresholds, each temperature profiles is assigned a characteristic pressure, pg, down to which the profile is characterized as good for use for data assimilation purposes. We have conducted forecast impact experiments assimilating AIRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the

  17. In-flight and simulated aircraft fuel temperature measurements

    NASA Technical Reports Server (NTRS)

    Svehla, Roger A.

    1990-01-01

    Fuel tank measurements from ten flights of an L1011 commercial aircraft are reported for the first time. The flights were conducted from 1981 to 1983. A thermocouple rake was installed in an inboard wing tank and another in an outboard tank. During the test periods of either 2 or 5 hr, at altitudes of 10,700 m (35,000 ft) or higher, either the inboard or the outboard tank remained full. Fuel temperature profiles generally developed in the expected manner. The bulk fuel was mixed by natural convection to a nearly uniform temperature, especially in the outboard tank, and a gradient existed at the bottom conduction zone. The data indicated that when full, the upper surface of the inboard tank was wetted and the outboard tank was unwetted. Companion NASA Lewis Research Center tests were conducted in a 0.20 cubic meter (52 gal) tank simulator of the outboard tank, chilled on the top and bottom, and insulated on the sides. Even though the simulator tank had no internal components corresponding to the wing tank, temperatures agreed with the flight measurements for wetted upper surface conditions, but not for unwetted conditions. It was concluded that if boundary conditions are carefully controlled, simulators are a useful way of evaluating actual flight temperatures.

  18. Pyrolysis and combustion of tobacco in a cigarette smoking simulator under air and nitrogen atmosphere.

    PubMed

    Busch, Christian; Streibel, Thorsten; Liu, Chuan; McAdam, Kevin G; Zimmermann, Ralf

    2012-04-01

    A coupling between a cigarette smoking simulator and a time-of-flight mass spectrometer was constructed to allow investigation of tobacco smoke formation under simulated burning conditions. The cigarette smoking simulator is designed to burn a sample in close approximation to the conditions experienced by a lit cigarette. The apparatus also permits conditions outside those of normal cigarette burning to be investigated for mechanistic understanding purposes. It allows control of parameters such as smouldering and puff temperatures, as well as combustion rate and puffing volume. In this study, the system enabled examination of the effects of "smoking" a cigarette under a nitrogen atmosphere. Time-of-flight mass spectrometry combined with a soft ionisation technique is expedient to analyse complex mixtures such as tobacco smoke with a high time resolution. The objective of the study was to separate pyrolysis from combustion processes to reveal the formation mechanism of several selected toxicants. A purposely designed adapter, with no measurable dead volume or memory effects, enables the analysis of pyrolysis and combustion gases from tobacco and tobacco products (e.g. 3R4F reference cigarette) with minimum aging. The combined system demonstrates clear distinctions between smoke composition found under air and nitrogen smoking atmospheres based on the corresponding mass spectra and visualisations using principal component analysis. PMID:22392377

  19. Nitric Oxide PLIF Visualization of Simulated Fuel-Air Mixing in a Dual-Mode Scramjet

    NASA Technical Reports Server (NTRS)

    Cantu, Luca M. L.; Gallo, Emanuela C. A.; Cutler, Andrew D.; Bathel, Brett F.; Danehy, Paul M.; Rockwell, Robert D.; Goyne, Christopher P.; McDaniel, James C.

    2015-01-01

    Nitric oxide (NO) planar induced laser fluorescence (PLIF) measurements have been performed in a small scale scramjet combustor at the University of Virginia Aerospace Research Laboratory at nominal simulated Mach 5 flight. A mixture of NO and N2 was injected at the upstream end of the inlet isolator as a surrogate for ethylene fuel, and the mixing of this fuel simulant was studied with and without a shock train. The shock train was produced by an air throttle, which simulated the blockage effects of combustion downstream of the cavity flame holder. NO PLIF signal was imaged in a plane orthogonal to the freestream at the leading edge of the cavity. Instantaneous planar images were recorded and analyzed to identify the most uniform cases, which were achieved by varying the location of the fuel injection and shock train. This method was used to screen different possible fueling configurations to provide optimized test conditions for follow-on combustion measurements using ethylene fuel. A theoretical study of the selected NO rotational transitions was performed to obtain a LIF signal that is linear with NO mole fraction and approximately independent of pressure and temperature.

  20. Hypothetical air ingress scenarios in advanced modular high temperature gas cooled reactors

    SciTech Connect

    Kroeger, P.G.

    1988-01-01

    Considering an extremely hypothetical scenario of complete cross duct failure and unlimited air supply into the reactor vessel of a modular high temperature gas cooled ractor, it is found that the potential air inflow remains limited due to the high friction pressure drop through the active core. All incoming air will be oxidized to CO and some local external burning would be temporarily possible in such a scenario. The accident would have to continue with unlimited air supply for hundreds of hours before the core structural integrity would be jeopardized.

  1. Quantum Mechanical Corrections to Simulated Shock Hugoniot Temperatures

    SciTech Connect

    Goldman, N; Reed, E; Fried, L E

    2009-07-17

    The authors present a straightforward method for the inclusion of quantum nuclear vibrational effects in molecular dynamics calculations of shock Hugoniot temperatures. Using a grueneisen equation of state and a quasi-harmonic approximation to the vibrational energies, they derive a simple, post-processing method for calculation of the quantum corrected Hugoniot temperatures. They have used our novel technique on ab initio simulations of both shock compressed water and methane. Our results indicate significantly closer agreement with all available experimental temperature data for these two systems. Our formalism and technique can be easily applied to a number of different shock compressed molecular liquids or covalent solids, and has the potential to decrease the large uncertainties inherent in many experimental Hugoniot temperature measurements of these systems.

  2. Comparison of Vertical Soundings and Sidewall Air Temperature Measurements in a Small Alpine Basin

    SciTech Connect

    Whiteman, Charles D.; Eisenbach, Stefan; Pospichal, Bernhard; Steinacker, Reinhold

    2004-11-01

    Tethered balloon soundings from two sites on the floor of a 1-km diameter limestone sinkhole in the Eastern Alps are compared with pseudo-vertical temperature ‘soundings’ from three lines of temperature data loggers on the basin’s northwest, southwest and southeast sidewalls. Under stable nighttime conditions with low background winds, the pseudo-vertical profiles from all three lines were good proxies for free air temperature soundings over the basin center, with a mean nighttime cold temperature bias of about 0.4°C and a standard deviation of 0.4°C. Cold biases were highest in the upper basin where relatively warm air subsides to replace air that spills out of the basin through the lowest altitude saddle. On a windy night, standard deviations increased to 1 - 2°C. After sunrise, the varying exposures of the data loggers to sunlight made the pseudo-vertical profiles less useful as proxies for free air soundings. The good correspondence between sidewall and free air temperatures during high static stability conditions suggests that sidewall soundings will prove useful in monitoring temperatures and vertical temperature gradients in the sinkhole. The sidewall soundings can produce more frequent profiles at less cost than tethersondes or rawinsondes, and provide valuable advantages for some types of meteorological analyses.

  3. Summertime Temperatures in Buildings Without Air-Conditioning.

    ERIC Educational Resources Information Center

    Loudon, A. G.

    Many modern buildings become uncomfortably warm during sunny spells in the summer, and until recently there was no simple, reliable method of assessing at the design stage whether a building would become overheated. This paper describes a method of calculating summertime temperatures which was developed at the Building Research Station, and gives…

  4. Measured Performance of a Low Temperature Air Source Heat Pump

    SciTech Connect

    Johnson, R. K.

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor 'boosted heat pump' technology. The Low Temperature Heat Pumpsystem operates with four increasing levels of capacity (heat output) as the outdoor temperature drops. The system was shown to select capacity correctly, supplying the appropriate amount of heat to the house across the full range of outdoor temperatures. The system's Coefficient of Performance (Seasonal COP, or SCOP) over two entire winters was calculated, based on measured data, to be 3.29over the first winter and 2.68 over the second winter. A second seasonal efficiency calculation by a different method yielded a SCOP of 2.78 for the first winter and 2.83 for the second winter. This second seasonal efficiency calculation was determined by comparing measured heat pump energy use to the in situ energy use with resistance heat alone. This method is the ratio of the slopes of thedaily energy use load lines.

  5. CFD simulation and optimization of the capillary throttling of air-flotation unit

    NASA Astrophysics Data System (ADS)

    Bin, Huang; Yi, Jiajing; Tao, Jiayue; Lu, Rongsheng

    2016-01-01

    With respect to orifice throttling or compensating, capillary throttling has following advantages: smaller mass flow rate and stronger anti-interference ability. This paper firstly gives the required average pressure of air-film when shipping a piece of LCD glass. Then, dimensional flow model of the capillary throttling of air-flotation unit is established. Based on the model, we firstly analyze the flowing process of the lubricated air through the capillary. Secondly, the pressure distribution equation of air-film is derived from the Navier-Stokes Equation. Furthermore, the approximate functional relations between model parameters and static characteristics of the air-film, such as mass flow rate, static bearing capacity, are obtained and then influence of the former on the latter is analyzed . Finally, according to the continuity of air flow, the function relation between model parameters and pressure of core nodes in the air-film is also derived. On foundation of theoretical analysis, the impacts of each model parameter on static characteristics of the air-film flow field, are respectively simulated and analyzed by CFD software Fluent. Based on these simulations and analysis, radius and length of the capillary, density of the gas supply orifices and other model parameters are optimized. Finally, the best unit model is acquired, which greatly improves the static working performance of air-film in air-flotation unit. Research results of this paper can provide guidance and basis for the design and optimization of air-flotation transporting system.

  6. Computational simulation of high temperature metal matrix composite behavior

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Chamis, Christos C.

    1991-01-01

    Computational procedures are described to simulate the thermal and mechanical behavior of high temperature metal matrix composite (HT MMC) in the following four broad areas: (1) behavior of HT MMC from micromechanics to laminate; (2) HT MMC structural response for simple and complex structural components; (3) HT MMC microfracture; and (4) tailoring of HT MMC behavior for optimum specific performance. Representative results from each area are presented to illustrate the effectiveness of the computational simulation procedures. Relevant reports are referenced for extended discussion regarding the specific area.

  7. Characteristics of Gaseous Diffusion Flames with High Temperature Combustion Air in Microgravity

    NASA Technical Reports Server (NTRS)

    Ghaderi, M.; Gupta, A. K.

    2003-01-01

    The characteristics of gaseous diffusion flames have been obtained using high temperature combustion air under microgravity conditions. The time resolved flame images under free fall microgravity conditions were obtained from the video images obtained. The tests results reported here were conducted using propane as the fuel and about 1000 C combustion air. The burner included a 0.686 mm diameter central fuel jet injected into the surrounding high temperature combustion air. The fuel jet exit Reynolds number was 63. Several measurements were taken at different air preheats and fuel jet exit Reynolds number. The resulting hybrid color flame was found to be blue at the base of the flame followed by a yellow color flame. The length and width of flame during the entire free fall conditions has been examined. Also the relative flame length and width for blue and yellow portion of the flame has been examined under microgravity conditions. The results show that the flame length decreases and width increases with high air preheats in microgravity condition. In microgravity conditions the flame length is larger with normal temperature combustion air than high temperature air.

  8. Usefulness of AIRS-Derived OLR, Temperature, Water Vapor and Cloudiness Anomaly Trends for GCM Validation

    NASA Technical Reports Server (NTRS)

    Molnar, Gyula I.; Susskind, Joel; Iredell, Lena F.

    2010-01-01

    climate variability] at the common 1x1 degree GCM grid-scale by creating spatial anomaly "trends" based on the first 7+ years of AIRS Version 5 Leve13 data. We suggest that modelers should compare these with their (coupled) GCM's performance covering the same period. We evaluate temporal variability and interrelations of climatic anomalies on global to regional e.g., deep Tropical Hovmoller diagrams, El-Nino-related variability scales, and show the effects of El-Nino-La Nina activity on tropical anomalies and trends of water vapor cloud cover and OLR. For GCMs to be trusted highly for long-term climate change predictions, they should be able to reproduce findings similar to these. In summary, the AIRS-based climate variability analyses provide high quality, informative and physically plausible interrelationships among OLR, temperature, humidity and cloud cover both on the spatial and temporal scales. GCM validations can use these results even directly, e. g., by creating 1x1 degree trendmaps for the same period in coupled climate simulations.

  9. Spectroscopic temperature measurements of air breakdown plasma using a 110 GHz megawatt gyrotron beam

    SciTech Connect

    Hummelt, J. S.; Shapiro, M. A.; Temkin, R. J.

    2012-12-15

    Temperature measurements are presented of a non-equilibrium air breakdown plasma using optical emission spectroscopy. A plasma is created with a focused 110 GHz 3 {mu}s pulse gyrotron beam in air that produces power fluxes exceeding 1 MW/cm{sup 2}. Rotational and vibrational temperatures are spectroscopically measured over a pressure range of 1-100 Torr as the gyrotron power is varied above threshold. The temperature dependence on microwave field as well as pressure is examined. Rotational temperature measurements of the plasma reveal gas temperatures in the range of 300-500 K and vibrational temperatures in the range of 4200-6200 K. The vibrational and rotational temperatures increase slowly with increasing applied microwave field over the range of microwave fields investigated.

  10. A COMPUTER SIMULATION MODEL--FOR ANALYZING MOBILE SOURCE AIR POLLUTION CONTROL STRATEGIES

    EPA Science Inventory

    This report describes MATHAIR, a computer model that simulates the impacts of strategies for controlling mobile source air pollutants. Vehicle miles traveled (VMT) for different modes of ground transportation are predicted by a transportation module. Given VMT predictions, an inv...

  11. Simulations of magnetic hysteresis loops at high temperatures

    SciTech Connect

    Plumer, M. L.; Whitehead, J. P.; Fal, T. J.; Ek, J. van; Mercer, J. I.

    2014-09-28

    The kinetic Monte-Carlo algorithm as well as standard micromagnetics are used to simulate MH loops of high anisotropy magnetic recording media at both short and long time scales over a wide range of temperatures relevant to heat-assisted magnetic recording. Microscopic parameters, common to both methods, were determined by fitting to experimental data on single-layer FePt-based media that uses the Magneto-Optic Kerr effect with a slow sweep rate of 700 Oe/s. Saturation moment, uniaxial anisotropy, and exchange constants are given an intrinsic temperature dependence based on published atomistic simulations of FePt grains with an effective Curie temperature of 680 K. Our results show good agreement between micromagnetics and kinetic Monte Carlo results over a wide range of sweep rates. Loops at the slow experimental sweep rates are found to become more square-shaped, with an increasing slope, as temperature increases from 300 K. These effects also occur at higher sweep rates, typical of recording speeds, but are much less pronounced. These results demonstrate the need for accurate determination of intrinsic thermal properties of future recording media as input to micromagnetic models as well as the sensitivity of the switching behavior of thin magnetic films to applied field sweep rates at higher temperatures.

  12. The effect of simulated air conditions on N95 filtering facepiece respirators performance.

    PubMed

    Ramirez, Joel A; O'Shaughnessy, Patrick T

    2016-07-01

    The objective of this study was to determine the effect of several simulated air environmental conditions on the particle penetration and the breathing resistance of two N95 filtering facepiece respirator (FFR) models. The particle penetration and breathing resistance of the respirators were evaluated in a test system developed to mimic inhalation and exhalation breathing while relative humidity and temperature were modified. Breathing resistance was measured over 120 min using a calibrated pressure transducer under four different temperature and relative humidity conditions without aerosol loading. Particle penetration was evaluated before and after the breathing resistance test at room conditions using a sodium chloride aerosol measured with a scanning mobility particle sizer. Results demonstrated that increasing relative humidity and lowering external temperature caused significant increases in breathing resistance (p < 0.001). However, these same conditions did not influence the penetration or most penetrating particle size of the tested FFRs. The increase in breathing resistance varied by FFR model suggesting that some FFR media are less influenced by high relative humidity. PMID:26861653

  13. SIMULATION OF AEROSOL DYNAMICS: A COMPARATIVE REVIEW OF ALGORITHMS USED IN AIR QUALITY MODELS

    EPA Science Inventory

    A comparative review of algorithms currently used in air quality models to simulate aerosol dynamics is presented. This review addresses coagulation, condensational growth, nucleation, and gas/particle mass transfer. Two major approaches are used in air quality models to repres...

  14. Dynamic Evaluation of Long-Term Air Quality Model Simulations Over the Northeastern U.S.

    EPA Science Inventory

    Dynamic model evaluation assesses a modeling system's ability to reproduce changes in air quality induced by changes in meteorology and/or emissions. In this paper, we illustrate various approaches to dynamic mode evaluation utilizing 18 years of air quality simulations perform...

  15. Diagnostic Analysis of Ozone Concentrations Simulated by Two Regional-Scale Air Quality Models

    EPA Science Inventory

    Since the Community Multiscale Air Quality modeling system (CMAQ) and the Weather Research and Forecasting with Chemistry model (WRF/Chem) use different approaches to simulate the interaction of meteorology and chemistry, this study compares the CMAQ and WRF/Chem air quality simu...

  16. FINAL EVALUATION OF URBAN-SCALE PHOTOCHEMICAL AIR QUALITY SIMULATION MODELS

    EPA Science Inventory

    The research study discussed here is a continuation of previous work whose goal was to determine the accuracy of several selected urban photochemical air quality simulation models using data from the Regional Air Pollution Study in St. Louis. This work reports on the testing of t...

  17. IAQPC: INDOOR AIR QUALITY SIMULATOR FOR PERSONAL COMPUTERS: VOLUME 1. TECHNICAL MANUAL

    EPA Science Inventory

    The two-volume report describes the development of an indoor air quality simulator for personal computers (IAQPC), a program that addresses the problems of indoor air contamination. The program-- systematic, user-friendly, and computer-based--can be used by administrators and eng...

  18. IAQPC: INDOOR AIR QUALITY SIMULATOR FOR PERSONAL COMPUTERS: VOLUME 2. USER'S GUIDE

    EPA Science Inventory

    The two-volume report describes the development of an indoor air quality simulator for personal computers (IAQPC), a program that addresses the problems of indoor air contamination. The program-- systematic, user-friendly, and computer-based--can be used by administrators and eng...

  19. Simulated Three-Dimensional Computer Graphics Training Display for Air Weapons Controllers. Final Report.

    ERIC Educational Resources Information Center

    Finegold, Lawrence S.; And Others

    The research and development project demonstrated the viability of a simulated training system to address training issues related to three-dimensional air intercept tactics and geometry, and resulted in the production of two videotapes for use in the United States Air Force Interceptor Weapons School. An introduction discusses the overall…

  20. Extreme Temperatures and Their Mechanisms in NARCCAP Simulations

    NASA Astrophysics Data System (ADS)

    Horton, R. M.; Rosenzweig, C.; Liu, J.; Bader, D.

    2012-12-01

    Radley M. Horton, Daniel A. Bader, Jiping Liu, and Cynthia Rosenzweig Using 8 GCM-RCM pairings from NARCCAP simulations, we present evidence that for large parts of the United States, the once-per-year warmest maximum temperature and coldest minimum temperature events are projected to warm significantly more than corresponding seasonal mean temperatures (in summer and winter, respectively). We explore several possible mechanisms for the (often large) changes in extremes, including changes in local soil moisture and snow depth, and changes in regional dynamics. The relative role of the GCMs and RCMs in creating these changing patterns in once per year temperature extremes is explored by leveraging the fact that individual GCMs were paired with multiple RCMs, and vice-versa. For much of the U.S., the once per year high and/or low temperatures are associated with large societal impacts. Extreme high temperatures are associated with increased mortality, with infrastructure impacts ranging from increased energy demand to buckling of roads and rails. Extreme low temperatures are likewise associated with excess mortality, increasing energy demand for heating, and damage to transportation infrastructure. Almost by definition, once per year events happen frequently enough to be relevant for adaptation planning, and are not so rare as to require statistical techniques geared towards small sample sizes.

  1. Simulations of in situ air stripping demonstration at Savannah River

    SciTech Connect

    Robinson, B.A.; Rosenberg, N.D.; Zyvoloski, G.A.; Viswanathan, H.

    1994-06-01

    This report assesses the performance of the in situ air stripping technology demonstrated at the Savannah River Integrated Demonstration (SRID) site. This technology is a combination of air injection below the water table and vacuum extraction in the vadose zone, using a pair of horizontal wells. Our approach is based on the construction of a site-specific numerical model using the FEHM flow and transport code. We use the model as a tool to investigate improvements to performance, to improve the prediction of the performance of this technology over longer periods of time and at different sites, and to compare performance with other remediation technologies.

  2. The simulation of temperature distribution and relative humidity with liquid concentration of 50% using computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Yohana, Eflita; Yulianto, Mohamad Endy; Kwang-Hwang, Choi; Putro, Bondantio; Yohanes Aditya W., A.

    2015-12-01

    The study of humidity distribution simulation inside a room has been widely conducted by using computational fluid dynamics (CFD). Here, the simulation was done by employing inputs in the experiment of air humidity reduction in a sample house. Liquid dessicant CaCl2was used in this study to absorb humidity in the air, so that the enormity of humidity reduction occured during the experiment could be obtained.The experiment was conducted in the morning at 8 with liquid desiccant concentration of 50%, nozzle dimension of 0.2 mms attached in dehumidifier, and the debit of air which entered the sample house was 2.35 m3/min. Both in inlet and outlet sides of the room, a DHT 11 censor was installed and used to note changes in humidity and temperature during the experiment. In normal condition without turning on the dehumidifier, the censor noted that the average temperature inside the room was 28°C and RH of 65%.The experiment result showed that the relative humidity inside a sample house was decreasing up to 52% in inlet position. Further, through the results obtained from CFD simulation, the temperature distribution and relative humidity inside the sample house could be seen. It showed that the concentration of liquid desiccant of 50% experienced a decrease while the relative humidity distribution was considerably good since the average RH was 55% followed by the increase in air temperature of 29.2° C inside the sample house.

  3. Apparatus and Method for Measuring Air Temperature Ahead of an Aircraft for Controlling a Variable Inlet/Engine Assembly

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    2001-01-01

    The apparatus and method employ remote sensing to measure the air temperature a sufficient distance ahead of the aircraft to allow time for a variable inlet/engine assembly to be reconfigured in response to the measured temperature, to avoid inlet unstart and/or engine compressor stall. In one embodiment, the apparatus of the invention has a remote sensor for measuring at least one air temperature ahead of the vehicle and an inlet control system for varying the inlet. The remote sensor determines a change in temperature value using at least one temperature measurement and prior temperature measurements corresponding to the location of the aircraft. The control system uses the change in air temperature value to vary the inlet configuration to maintain the position of the shock wave during the arrival of the measured air in the inlet. In one embodiment, the method of the invention includes measuring at least one air temperature ahead of the vehicle, determining an air temperature at the vehicle from prior air temperature measurements, determining a change in temperature value using the air temperature at the vehicle and the at least one air temperature measurement ahead of the vehicle, and using the change in temperature value to-reposition the airflow inlet, to cause the shock wave to maintain substantially the same position within the inlet as the airflow temperature changes within the inlet.

  4. 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.

  5. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    SciTech Connect

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue Fang, Jing

    2015-10-15

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  6. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    NASA Astrophysics Data System (ADS)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue; Fang, Jing

    2015-10-01

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  7. Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure.

    PubMed

    Laakso, Ilkka; Hirata, Akimasa

    2011-12-01

    Numerical models of the human thermoregulatory system can be used together with realistic voxel models of the human anatomy to simulate the body temperature increases caused by the power absorption from radio-frequency electromagnetic fields. In this paper, the Pennes bioheat equation with a thermoregulatory model is used for calculating local peak temperatures as well as the body-core-temperature elevation in a realistic human body model for grounded plane-wave exposures at frequencies 39, 800 and 2400 MHz. The electromagnetic power loss is solved by the finite-difference time-domain (FDTD) method, and the discretized bioheat equation is solved by the geometric multigrid method. Human thermoregulatory models contain numerous thermophysiological and computational parameters--some of which may be subject to considerable uncertainty--that affect the simulated core and local temperature elevations. The goal of this paper is to find how greatly the computed temperature is influenced by changes in various modelling parameters, such as the skin blood flow rate, models for vasodilation and sweating, and clothing and air movement. The results show that the peak temperature rises are most strongly affected by the modelling of tissue blood flow and its temperature dependence, and mostly unaffected by the central control mechanism for vasodilation and sweating. Almost the opposite is true for the body-core-temperature rise, which is however typically greatly lower than the peak temperature rise. It also seems that ignoring the thermoregulation and the blood temperature increase is a good approximation when the local 10 g averaged specific absorption rate is smaller than 10 W kg(-1). PMID:22080753

  8. Dominant factors affecting temperature rise in simulations of human thermoregulation during RF exposure

    NASA Astrophysics Data System (ADS)

    Laakso, Ilkka; Hirata, Akimasa

    2011-12-01

    Numerical models of the human thermoregulatory system can be used together with realistic voxel models of the human anatomy to simulate the body temperature increases caused by the power absorption from radio-frequency electromagnetic fields. In this paper, the Pennes bioheat equation with a thermoregulatory model is used for calculating local peak temperatures as well as the body-core-temperature elevation in a realistic human body model for grounded plane-wave exposures at frequencies 39, 800 and 2400 MHz. The electromagnetic power loss is solved by the finite-difference time-domain (FDTD) method, and the discretized bioheat equation is solved by the geometric multigrid method. Human thermoregulatory models contain numerous thermophysiological and computational parameters—some of which may be subject to considerable uncertainty—that affect the simulated core and local temperature elevations. The goal of this paper is to find how greatly the computed temperature is influenced by changes in various modelling parameters, such as the skin blood flow rate, models for vasodilation and sweating, and clothing and air movement. The results show that the peak temperature rises are most strongly affected by the modelling of tissue blood flow and its temperature dependence, and mostly unaffected by the central control mechanism for vasodilation and sweating. Almost the opposite is true for the body-core-temperature rise, which is however typically greatly lower than the peak temperature rise. It also seems that ignoring the thermoregulation and the blood temperature increase is a good approximation when the local 10 g averaged specific absorption rate is smaller than 10 W kg-1.

  9. Finite element simulation of temperature dependent free surface flows

    NASA Technical Reports Server (NTRS)

    Engelman, M. S.; Sani, R. L.

    1985-01-01

    The method of Engelman and Sani (1984) for a finite-element simulation of incompressible surface flows with a free and/or moving fluid interface, such as encountered in crystal growth and coating and polymer technology, is extended to temperature-dependent flows, including the effect of temperature-dependent surface tension. The basic algorithm of Saito and Scriven (1981) and Ruschak (1980) has been generalized and implemented in a robust and versatile finite-element code that can be employed with relative ease for the simulation of free-surface problems in complex geometries. As a result, the costly dependence on the Newton-Raphson algorithm has been eliminated by replacing it with a quasi-Newton iterative method, which nearly retains the superior convergence properties of the Newton-Raphson method.

  10. United States Air Force Training Line Simulator. Final Report.

    ERIC Educational Resources Information Center

    Nauta, Franz; Pierce, Michael B.

    This report describes the technical aspects and potential applications of a computer-based model simulating the flow of airmen through basic training and entry-level technical training. The objective of the simulation is to assess the impacts of alternative recruit classification and training policies under a wide variety of assumptions regarding…

  11. An error model for GCM precipitation and temperature simulations

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Woldemeskel, F.; Mehrotra, R.; Sivakumar, B.

    2012-04-01

    Water resources assessments for future climates require meaningful simulations of likely precipitation and evaporation for simulation of flow and derived quantities of interest. The current approach for making such assessments involve using simulations from one or a handful of General Circulation Models (GCMs), for usually one assumed future greenhouse gas emission scenario, deriving associated flows and the planning or design attributes required, and using these as the basis of any planning or design that is needed. An assumption that is implicit in this approach is that the single or multiple simulations being considered are representative of what is likely to occur in the future. Is this a reasonable assumption to make and use in designing future water resources infrastructure? Is the uncertainty in the simulations captured through this process a real reflection of the likely uncertainty, even though a handful of GCMs are considered? Can one, instead, develop a measure of this uncertainty for a given GCM simulation for all variables in space and time, and use this information as the basis of water resources planning (similar to using "input uncertainty" in rainfall-runoff modelling)? These are some of the questions we address in course of this presentation. We present here a new basis for assigning a measure of uncertainty to GCM simulations of precipitation and temperature. Unlike other alternatives which assess overall GCM uncertainty, our approach leads to a unique measure of uncertainty in the variable of interest for each simulated value in space and time. We refer to this as an error model of GCM precipitation and temperature simulations, to allow a complete assessment of the merits or demerits associated with future infrastructure options being considered, or mitigation plans being devised. The presented error model quantifies the error variance of GCM monthly precipitation and temperature, and reports it as the Square Root Error Variance (SREV

  12. Estimation of daily mean air temperature from satellite derived radiometric data

    NASA Technical Reports Server (NTRS)

    Phinney, D.

    1976-01-01

    The Screwworm Eradication Data System (SEDS) at JSC utilizes satellite derived estimates of daily mean air temperature (DMAT) to monitor the effect of temperature on screwworm populations. The performance of the SEDS screwworm growth potential predictions depends in large part upon the accuracy of the DMAT estimates.

  13. Prediction of air temperature for thermal comfort of people using sleeping bags: a review

    NASA Astrophysics Data System (ADS)

    Huang, Jianhua

    2008-11-01

    Six models for determining air temperatures for thermal comfort of people using sleeping bags were reviewed. These models were based on distinctive metabolic rates and mean skin temperatures. All model predictions of air temperatures are low when the insulation values of the sleeping bag are high. Nevertheless, prediction variations are greatest for the sleeping bags with high insulation values, and there is a high risk of hypothermia if an inappropriate sleeping bag is chosen for the intended conditions of use. There is, therefore, a pressing need to validate the models by wear trial and determine which one best reflects ordinary consumer needs.

  14. Characterizing Air Temperature Changes in the Tarim Basin over 1960–2012

    PubMed Central

    Peng, Dongmei; Wang, Xiujun; Zhao, Chenyi; Wu, Xingren; Jiang, Fengqing; Chen, Pengxiang

    2014-01-01

    There has been evidence of warming rate varying largely over space and between seasons. However, little has been done to evaluate the spatial and temporal variability of air temperature in the Tarim Basin, northwest China. In this study, we collected daily air temperature from 19 meteorological stations for the period of 1960–2012, and analyzed annual mean temperature (AMT), the annual minimum (Tmin) and maximum temperature (Tmax), and mean temperatures of all twelve months and four seasons and their anomalies. Trend analyses, standard deviation of the detrended anomaly (SDDA) and correlations were carried out to characterize the spatial and temporal variability of various mean air temperatures. Our data showed that increasing trend was much greater in the Tmin (0.55°C/10a) than in the AMT (0.25°C/10a) and Tmax (0.12°C/10a), and the fluctuation followed the same order. There were large spatial variations in the increasing trends of both AMT (from −0.09 to 0.43 °C/10a) and Tmin (from 0.15 to 1.12°C/10a). Correlation analyses indicated that AMT had a significantly linear relationship with Tmin and the mean temperatures of four seasons. There were also pronounced changes in the monthly air temperature from November to March at decadal time scale. The seasonality (i.e., summer and winter difference) of air temperature was stronger during the period of 1960–1979 than over the recent three decades. Our preliminary analyses indicated that local environmental conditions (such as elevation) might be partly responsible for the spatial variability, and large scale climate phenomena might have influences on the temporal variability of air temperature in the Tarim Basin. In particular, there was a significant correlation between index of El Niño-Southern Oscillation (ENSO) and air temperature of May (P = 0.004), and between the index of Pacific Decadal Oscillation (PDO) and air temperature of July (P = 0.026) over the interannual to decadal time scales. PMID

  15. Characterizing air temperature changes in the Tarim Basin over 1960-2012.

    PubMed

    Peng, Dongmei; Wang, Xiujun; Zhao, Chenyi; Wu, Xingren; Jiang, Fengqing; Chen, Pengxiang

    2014-01-01

    There has been evidence of warming rate varying largely over space and between seasons. However, little has been done to evaluate the spatial and temporal variability of air temperature in the Tarim Basin, northwest China. In this study, we collected daily air temperature from 19 meteorological stations for the period of 1960-2012, and analyzed annual mean temperature (AMT), the annual minimum (T min) and maximum temperature (Tmax), and mean temperatures of all twelve months and four seasons and their anomalies. Trend analyses, standard deviation of the detrended anomaly (SDDA) and correlations were carried out to characterize the spatial and temporal variability of various mean air temperatures. Our data showed that increasing trend was much greater in the T min (0.55°C/10a) than in the AMT (0.25°C/10a) and Tmax (0.12°C/10a), and the fluctuation followed the same order. There were large spatial variations in the increasing trends of both AMT (from -0.09 to 0.43 °C/10a) and T min (from 0.15 to 1.12°C/10a). Correlation analyses indicated that AMT had a significantly linear relationship with T min and the mean temperatures of four seasons. There were also pronounced changes in the monthly air temperature from November to March at decadal time scale. The seasonality (i.e., summer and winter difference) of air temperature was stronger during the period of 1960-1979 than over the recent three decades. Our preliminary analyses indicated that local environmental conditions (such as elevation) might be partly responsible for the spatial variability, and large scale climate phenomena might have influences on the temporal variability of air temperature in the Tarim Basin. In particular, there was a significant correlation between index of El Niño-Southern Oscillation (ENSO) and air temperature of May (P = 0.004), and between the index of Pacific Decadal Oscillation (PDO) and air temperature of July (P = 0.026) over the interannual to decadal time scales. PMID:25375648

  16. Simulation of seasonal US precipitation and temperature by the nested CWRF-ECHAM system

    NASA Astrophysics Data System (ADS)

    Chen, Ligang; Liang, Xin-Zhong; DeWitt, David; Samel, Arthur N.; Wang, Julian X. L.

    2016-02-01

    This study investigates the refined simulation skill that results when the regional Climate extension of the Weather Research and Forecasting (CWRF) model is nested in the ECMWF Hamburg version 4.5 (ECHAM) atmospheric general circulation model over the United States during 1980-2009, where observed sea surface temperatures are used in both models. Over the contiguous US, for each of the four seasons from winter to fall, CWRF reduces the root mean square error of the ECHAM seasonal mean surface air temperature simulation by 0.19, 0.82, 2.02 and 1.85 °C, and increases the equitable threat score of seasonal mean precipitation by 0.18, 0.11, 0.09 and 0.12. CWRF also simulates much more realistically daily precipitation frequency and heavy precipitation events, typically over the Central Great Plains, Cascade Mountains and Gulf Coast States. These CWRF skill enhancements are attributed to the increased spatial resolution and physics refinements in representing orographic, terrestrial hydrology, convection, and cloud-aerosol-radiation effects and their interactions. Empirical orthogonal function analysis of seasonal mean precipitation and surface air temperature interannual variability shows that, in general, CWRF substantially improves the spatial distribution of both quantities, while temporal evolution (i.e. interannual variability) of the first 3 primary patterns is highly correlated with that of the driving ECHAM (except for summer precipitation), and they both have low temporal correlations against observations. During winter, when large-scale forcing dominates, both models also have similar responses to strong ENSO signals where they successfully capture observed precipitation composite anomalies but substantially fail to reproduce surface air temperature anomalies. When driven by the ECMWF Reanalysis Interim, CWRF produces a very realistic interannual evolution of large-scale precipitation and surface air temperature patterns where the temporal correlations with

  17. Direct numerical simulation of a turbulent stably stratified air flow above a wavy water surface

    NASA Astrophysics Data System (ADS)

    Druzhinin, O. A.; Troitskaya, Yu. I.; Zilitinkevich, S. S.

    2016-01-01

    The influence of the roughness of the underlaying water surface on turbulence is studied in a stably stratified boundary layer (SSBL). Direct numerical simulation (DNS) is conducted at various Reynolds (Re) and Richardson (Ri) numbers and the wave steepness ka. It is shown that, at constant Re, the stationary turbulent regime is set in at Ri below the threshold value Ri c depending on Re. At Ri > Ri c , in the absence of turbulent fluctuations near the wave water surface, three-dimensional quasiperiodical structures are identified and their threshold of origin depends on the steepness of the surface wave on the water surface. This regime is called a wave pumping regime. The formation of three-dimensional structures is explained by the development of parametric instability of the disturbances induced by the surface water in the air flow. The DNS results are quite consistent with prediction of the theoretical model of the SSBL flow, in which solutions for the disturbances of the fields of velocity and temperature in the wave pumping regime are found to be a solution of a two-dimensional linearized system with the heterogeneous boundary condition, which is caused by the presence of the surface wave. In addition to the turbulent fluctuations, the three-dimensional structures in the wave pumping regime provide for the transfer of impulse and heat, i.e., the increase in the roughness of the water-air boundary caused by the presence of waves intensifies the exchange in the SSBL.

  18. TAC BRAWLER - An application of engagement simulation modeling to simulator visual system display requirements for air combat maneuvering

    NASA Technical Reports Server (NTRS)

    Kerchner, R. M.; Hughes, R. G.; Lee, A.

    1984-01-01

    The TAC BRAWLER air combat simulation models both the acquisition and use of visual information by the pilot. It was used to provide the designers of manned simulators for air-to-air combat with information regarding the training implications of display system resolution, inherent target contrast, field of view, and transport delay. Various display designs were simulated, and the resulting quantitative and qualitative differences in engagements were considered indicators of possible mistraining. Display resolution was found to alter combats primarily through its effect on detection ranges; the 'pixel averaging' contrast management technique was shown to largely compensate for this problem. Transport delay significantly degrades pilot tracking ability, but the training impact of the effect is unclear.

  19. 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

  20. 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

  1. The temperature fields measurement of air in the car cabin by infrared camera

    NASA Astrophysics Data System (ADS)

    Pešek, M.

    2013-04-01

    The article deals with the temperature fields measurement of air using the Jenoptic Variocam infrared camera inside the car Škoda Octavia Combi II. The temperature fields with the use of auxiliary material with a high emissivity value were visualized. The measurements through the viewing window with a high transmissivity value were performed. The viewing windows on the side car door were placed. In the rear car area, the temperature fields of air on the spacious sheet of auxiliary material were visualized which is a suitable method for 2D airstreams. In the front car area, the temperature fields in the air were measured with the use of the measuring net which is suitable for 3D airstreams measuring.

  2. The upper explosion limit of lower alkanes and alkenes in air at elevated pressures and temperatures.

    PubMed

    Van den Schoor, F; Verplaetsen, F

    2006-01-16

    The upper explosion limit (UEL) of ethane-air, propane-air, n-butane-air, ethylene-air and propylene-air mixtures is determined experimentally at initial pressures up to 30 bar and temperatures up to 250 degrees C. The experiments are performed in a closed spherical vessel with an internal diameter of 200 mm. The mixtures are ignited by fusing a coiled tungsten wire, placed at the centre of the vessel, by electric current. Flame propagation is said to have taken place if there is a pressure rise of at least 1% of the initial pressure after ignition of the mixture. In the pressure-temperature range investigated, a linear dependence of UEL on temperature and a bilinear dependence on pressure are found except in the vicinity of the auto-ignition range. A comparison of the UEL data of the lower alkanes shows that the UEL expressed as equivalence ratio (the actual fuel/air ratio divided by the stoichiometric fuel/air ratio) increases with increasing carbon number in the homologous series of alkanes. PMID:16154265

  3. High Temperature Unfolding and Low Temperature Refolding Pathway of Chymotrypsin Inhibitor 2 Using Molecular Dynamics Simulation

    NASA Astrophysics Data System (ADS)

    Malau, N. D.; Sumaryada, T.

    2016-01-01

    The mechanism that explains the unfolding/refolding process of the protein is still a major problem that has not been fully understood. In this paper we present our study on the unfolding and refolding pathway of Chymotrypsin Inhibitor 2 (CI2) protein through a molecular dynamics simulation technique. The high temperature unfolding simulation were performed at 500 K for 35 ns. While the low temperature refolding simulation performed at 200 K for 35 ns. The unfolding and refolding pathway of protein were analysed by looking at the dynamics of root mean squared deviation (RMSD) and secondary structure profiles. The signatures of unfolding were observed from significant increase of RMSD within the time span of 10 ns to 35 ns. For the refolding process, the initial structure was prepared from the structure of unfolding protein at t=15 ns and T=500 K. Analysis have shown that some of the secondary structures of CI2 protein that have been damaged at high temperature can be refolded back to its initial structure at low temperature simulation. Our results suggest that most of α-helix structure of CI2 protein can be refolded back to its initial state, while only half beta-sheet structure can be reformed.

  4. Global gyrokinetic ion temperature gradient turbulence simulations of ITER

    NASA Astrophysics Data System (ADS)

    Villard, L.; Angelino, P.; Bottino, A.; Brunner, S.; Jolliet, S.; McMillan, B. F.; Tran, T. M.; Vernay, T.

    2013-07-01

    Global gyrokinetic simulations of ion temperature gradient (ITG) driven turbulence in an ideal MHD ITER equilibrium plasma are performed with the ORB5 code. The noise control and field-aligned Fourier filtering procedures implemented in ORB5 are essential in obtaining numerically healthy results with a reasonable amount of computational effort: typical simulations require 109 grid points, 109 particles and, despite a particle per cell ratio of unity, achieve a signal to noise ratio larger than 50. As compared with a circular concentric configuration with otherwise similar parameters (same ρ* = 1/720), the effective heat diffusivity is considerably reduced for the ITER MHD equilibrium. A self-organized radial structure appears, with long-lived zonal flows (ZF), modulating turbulence heat transport and resulting in a corrugated temperature gradient profile. The ratio of long-lived ZF to the fluctuating ZF is markedly higher for the ITER MHD equilibrium as compared with circular configurations, thereby producing a more effective ITG turbulence suppression, in spite of a higher linear growth rate. As a result, the nonlinear critical temperature gradient, R/LTcrit,NL, is about twice the linear critical temperature gradient, R/LTcrit,lin. Moreover, the heat transport stiffness above the nonlinear threshold is considerably reduced as compared with circular cases. Plasma elongation is probably one of the essential causes of this behaviour: indeed, undamped ZF residual levels and geodesic acoustic mode damping are both increasing with elongation. Other possible causes of the difference, such as magnetic shear profile effects, are also investigated.

  5. Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    SUsskind, Joel

    2008-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 pm C02 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 pm C02 observations are now used primarily in the generation of cloud cleared radiances Ri. This approach allows for the generation of accurate values of Ri and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by- channel error estimates for Ri. These error estimates are used for quality control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of quality control using the NASA GEOS-5 data assimilation system. Assimilation of quality controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done Operationally by ECMWF and NCEP. Forecasts resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

  6. Improving Forecast Skill by Assimilation of Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste

    2009-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of cloud cleared radiances R(sub i). This approach allows for the generation of accurate values of R(sub i) and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel error estimates for R(sub i). These error estimates are used for Quality Control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of Quality Control using the NASA GEOS-5 data assimilation system. Assimilation of Quality Controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done operationally by ECMWF and NCEP. Forecast resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

  7. Air Ingress Accident in a High Temperature Reactor with Prismatic Fuel

    SciTech Connect

    Haque, H.; Brinkmann, G.

    2006-07-01

    In this paper, the safety behavior of the new generation high temperature reactors (HTRs) with prismatic fuels during air ingress accident conditions has been investigated. These reactors conceived primarily for the production of hydrogen, are characterized by their inherent safety features with respect to passive decay heat removal through conduction, radiation and natural convection. Air ingress is an HTR specific event. The potential threat posed by air ingress lies in the chemical reaction of oxygen with hot graphite at a temperature above 500 deg. C leading to reaction heat and graphite corrosion. A substantial amount of graphite burn-off can take place only if sufficient amount of air enters into the core. In order to better assess the phenomena of air ingress into the reactor, it is postulated that breaks are present above and below the reactor core and that unobstructed ingress of air through them is possible. It is obvious that the air ingress incident has to be preceded by a depressurization accident. For this hypothetical scenario the maximum possible air flow rate through the core resulting solely from the pressure losses in the core is determined as a function of the break cross sections exposed above and below the core. This paper demonstrates the thermal behavior of the ANTARES reactor (operating inlet/outlet temperatures 450/850 deg. C) for various air flow rates with respect to graphite burn-off and maximum temperatures of fuel and bottom reflector region. It indicates the limiting time at which the graphite layer of fuel will be completely burnt-off and the pellets exposed. (authors)

  8. 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.

  9. A Multi-Operator Simulation for Investigation of Distributed Air Traffic Management Concepts

    NASA Technical Reports Server (NTRS)

    Peters, Mark E.; Ballin, Mark G.; Sakosky, John S.

    2002-01-01

    This paper discusses the current development of an air traffic operations simulation that supports feasibility research for advanced air traffic management concepts. The Air Traffic Operations Simulation (ATOS) supports the research of future concepts that provide a much greater role for the flight crew in traffic management decision-making. ATOS provides representations of the future communications, navigation, and surveillance (CNS) infrastructure, a future flight deck systems architecture, and advanced crew interfaces. ATOS also provides a platform for the development of advanced flight guidance and decision support systems that may be required for autonomous operations.

  10. Development of a large support surface for an air-bearing type zero-gravity simulator

    NASA Technical Reports Server (NTRS)

    Glover, K. E.

    1976-01-01

    The methods used in producing a large, flat surface to serve as the supporting surface for an air-bearing type zero-gravity simulator using low clearance, thrust-pad type air bearings are described. Major problems encountered in the use of self-leveled epoxy coatings in this surface are discussed and techniques are recommended which proved effective in overcoming these problems. Performance requirements of the zero-gravity simulator vehicle which were pertinent to the specification of the air-bearing support surface are also discussed.

  11. The effect of air temperature and human thermal indices on mortality in Athens, Greece

    NASA Astrophysics Data System (ADS)

    Nastos, Panagiotis T.; Matzarakis, Andreas

    2012-05-01

    This paper investigates whether there is any association between the daily mortality for the wider region of Athens, Greece and the thermal conditions, for the 10-year period 1992-2001. The daily mortality datasets were acquired from the Hellenic Statistical Service and the daily meteorological datasets, concerning daily maximum and minimum air temperature, from the Hellinikon/Athens meteorological station, established at the headquarters of the Greek Meteorological Service. Besides, the daily values of the thermal indices Physiologically Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) were evaluated in order to interpret the grade of physiological stress. The first step was the application of Pearson's χ 2 test to the compiled contingency tables, resulting in that the probability of independence is zero ( p = 0.000); namely, mortality is in close relation to the air temperature and PET/UTCI. Furthermore, the findings extracted by the generalized linear models showed that, statistically significant relationships ( p < 0.01) between air temperature, PET, UTCI and mortality exist on the same day. More concretely, on one hand during the cold period (October-March), a 10°C decrease in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 13%, 15%, 2%, 7% and 6% of the probability having a death, respectively. On the other hand, during the warm period (April-September), a 10°C increase in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 3%, 1%, 10%, 3% and 5% of the probability having a death, respectively. Taking into consideration the time lag effect of the examined parameters on mortality, it was found that significant effects of 3-day lag during the cold period appears against 1-day lag during the warm period. In spite of the general aspect that cold conditions seem to be favourable factors for daily mortality

  12. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

    NASA Technical Reports Server (NTRS)

    Bugbee, B.; Monje, O.; Tanner, B.

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  13. Ambient air pollution, temperature and out-of-hospital coronary deaths in Shanghai, China.

    PubMed

    Dai, Jinping; Chen, Renjie; Meng, Xia; Yang, Changyuan; Zhao, Zhuohui; Kan, Haidong

    2015-08-01

    Few studies have evaluated the effects of ambient air pollution and temperature in triggering out-of-hospital coronary deaths (OHCDs) in China. We evaluated the associations of air pollution and temperature with daily OHCDs in Shanghai, China from 2006 to 2011. We applied an over-dispersed generalized additive model and a distributed lag nonlinear model to analyze the effects of air pollution and temperature, respectively. A 10 μg/m(3) increase in the present-day PM10, PM2.5, SO2, NO2 and CO were associated with increases in OHCD mortality of 0.49%, 0.68%, 0.88%, 1.60% and 0.08%, respectively. A 1 °C decrease below the minimum-mortality temperature corresponded to a 3.81% increase in OHCD mortality on lags days 0-21, and a 1 °C increase above minimum-mortality temperature corresponded to a 4.61% increase over lag days 0-3. No effects were found for in-hospital coronary deaths. This analysis suggests that air pollution, low temperature and high temperature may increase the risk of OHCDs. PMID:25875162

  14. Effect of green roofs on air temperature; measurement study of well-watered and dry conditions

    NASA Astrophysics Data System (ADS)

    Solcerova, Anna; van de Ven, Frans; Wang, Mengyu; van de Giesen, Nick

    2016-04-01

    Rapid urbanization and increasing number and duration of heat waves poses a need for understanding urban climate and ways to mitigate extremely high temperatures. One of repeatedly suggested and often investigated methods to moderate the so called urban heat island are green roofs. This study investigates several extensive green roofs in Utrecht (NL) and their effect on air temperature right above the roof surface. Air temperature was measured 15 and 30 cm above the roof surface and also in the substrate. We show that under normal condition is air above green roof, compared to white gravel roof, colder at night and warmer during day. This suggest that green roofs might help decrease air temperatures at night, when the urban heat island is strongest, but possibly contribute to high temperatures during daytime. We also measured situation when the green roofs wilted and dried out. Under such conditions green roof exhibits more similar behavior to conventional white gravel roof. Interestingly, pattern of soil temperature remains almost the same for both dry and well-prospering green roof, colder during day and warmer at night. As such, green roof works as a buffer of diurnal temperature changes.

  15. Air temperature suitability for Plasmodium falciparum malaria transmission in Africa 2000-2012: a high-resolution spatiotemporal prediction

    PubMed Central

    2014-01-01

    Background Temperature suitability for malaria transmission is a useful predictor variable for spatial models of malaria infection prevalence. Existing continental or global models, however, are synoptic in nature and so do not characterize inter-annual variability in seasonal patterns of temperature suitability, reducing their utility for predicting malaria risk. Methods A malaria Temperature Suitability Index (TSI) was created by first modeling minimum and maximum air temperature with an eight-day temporal resolution from gap-filled MODerate Resolution Imaging Spectroradiometer (MODIS) daytime and night-time Land Surface Temperature (LST) datasets. An improved version of an existing biological model for malaria temperature suitability was then applied to the resulting temperature information for a 13-year data series. The mechanism underlying this biological model is simulation of emergent mosquito cohorts on a two-hour time-step and tracking of each cohort throughout its life to quantify the impact air temperature has on both mosquito survival and sporozoite development. Results The results of this research consist of 154 monthly raster surfaces that characterize spatiotemporal patterns in TSI across Africa from April 2000 through December 2012 at a 1 km spatial resolution. Generalized TSI patterns were as expected, with consistently high values in equatorial rain forests, seasonally variable values in tropical savannas (wet and dry) and montane areas, and low values in arid, subtropical regions. Comparisons with synoptic approaches demonstrated the additional information available within the dynamic TSI dataset that is lost in equivalent synoptic products derived from long-term monthly averages. Conclusions The dynamic TSI dataset presented here provides a new product with far richer spatial and temporal information than any other presently available for Africa. As spatiotemporal malaria modeling endeavors evolve, dynamic predictor variables such as the malaria

  16. Integration of a computational grid and virtual geographic environment to facilitate air pollution simulation

    NASA Astrophysics Data System (ADS)

    Xu, Bingli; Lin, Hui; Gong, Jianhua; Tang, Sammy; Hu, Ya; Nasser, Ibrahim Abdoul; Jing, Tao

    2013-04-01

    Air pollution, which is a global environmental problem, has been the hot research area among the scientists in the geoscience community. Air pollution simulation is of low-efficiency caused by the computation-intensive models, such as MM5 or WRF, and the complicated and unfriendly user interface. These issues are addressed in this paper by integrating computational grid and virtual geographic environment (VGE). The computational grid is employed to improve the computation efficiency of air pollution models. The VGE is used as a straightforward and easy to use interface to navigate the air pollution modeling workflow and improve the operational efficiencies of the models with respect to initiation, computation, and output visualization. On the aspect of technique implementation, this paper designs a framework and addresses the methodologies of the integration of computational grid and VGE. The prototype system, which integrates the computation grid of the Chinese University of Hong Kong (CUGrid) and a VGE to facilitate air pollution simulation based on the Mesoscale Model Version 5 (MM5), was developed. Based on the prototype system, a case was tested and the results indicate that the efficiencies of air pollution simulation on the model computation and workflow operation based on MM5 are increased significantly. This success also proves the reasonability of our general contribution of integrating computational grid and VGE to facilitate air pollution simulation.

  17. Characterizing Electron Temperature Gradient Turbulence Via Numerical Simulation

    SciTech Connect

    Nevins, W M; Candy, J; Cowley, S; Dannert, T; Dimits, A; Dorland, W; Estrada-Mila, C; Hammett, G W; Jenko, F; Pueschel, M J; Shumaker, D E

    2006-05-22

    Numerical simulations of electron temperature gradient (ETG) turbulence are presented which characterize the ETG fluctuation spectrum, establish limits to the validity of the adiabatic ion model often employed in studying ETG turbulence, and support the tentative conclusion that plasmaoperating regimes exist in which ETG turbulence produces sufficient electron heat transport to be experimentally relevant. We resolve prior controversies regarding simulation techniques and convergence by benchmarking simulations of ETG turbulence from four microturbulence codes, demonstrating agreement on the electron heat flux, correlation functions, fluctuation intensity, and rms flow shear at fixed simulation cross section and resolution in the plane perpendicular to the magnetic field. Excellent convergence of both continuum and particle-in-cell codes with time step and velocity-space resolution is demonstrated, while numerical issues relating to perpendicular (to the magnetic field) simulation dimensions and resolution are discussed. A parameter scan in the magnetic shear, s, demonstrates that the adiabatic ion model is valid at small values of s (s < 0.4 for the parameters used in this scan) but breaks down at higher magnetic shear. A proper treatment employing gyrokinetic ions reveals a steady increase in the electron heat transport with increasing magnetic shear, reaching electron heat transport rates consistent with analyses of experimental tokamak discharges.

  18. Coaxial injector spray characterization using water/air as simulants

    NASA Technical Reports Server (NTRS)

    Zaller, Michelle M.; Klem, Mark D.

    1991-01-01

    Quantitative information about the atomization of injector sprays is required to improve the accuracy of computational models that predict the performance and stability of liquid propellant rocket engines. An experimental program is being conducted at NASA-Lewis to measure the drop size and velocity distributions in shear coaxial injector sprays. A phase/Doppler interferometer is used to obtain drop size data in water air shear coaxial injector sprays. Droplet sizes and axial component of droplet velocities are measured at different radii for various combinations of water flow rate, air flow rate, injector liquid jet diameter, injector annular gap, and liquid post recess. Sauter mean diameters measured in the spray center 51 mm downstream of the liquid post tip range from 28 to 68 microns, and mean axial drop velocities at the same location range from 37 to 120 m/s. The shear coaxial injector sprays show a high degree of symmetry; the mean drop size and velocity profiles vary with liquid flow rate, post recess, and distance from the injector face. The drop size data can be used to estimate liquid oxygen/hydrogen spray drop sizes by correcting property differences between water-air and liquid oxygen/hydrogen.

  19. Assimilation of Quality Controlled AIRS Temperature Profiles using the NCEP GFS

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste; Iredell, Lena; Rosenberg, Robert

    2013-01-01

    We have previously conducted a number of data assimilation experiments using AIRS Version-5 quality controlled temperature profiles as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The data assimilation and forecast system we used was the Goddard Earth Observing System Model , Version-5 (GEOS-5) Data Assimilation System (DAS), which represents a combination of the NASA GEOS-5 forecast model with the National Centers for Environmental Prediction (NCEP) operational Grid Point Statistical Interpolation (GSI) global analysis scheme. All analyses and forecasts were run at a 0.5deg x 0.625deg spatial resolution. Data assimilation experiments were conducted in four different seasons, each in a different year. Three different sets of data assimilation experiments were run during each time period: Control; AIRS T(p); and AIRS Radiance. In the "Control" analysis, all the data used operationally by NCEP was assimilated, but no AIRS data was assimilated. Radiances from the Aqua AMSU-A instrument were also assimilated operationally by NCEP and are included in the "Control". The AIRS Radiance assimilation adds AIRS observed radiance observations for a select set of channels to the data set being assimilated, as done operationally by NCEP. In the AIRS T(p) assimilation, all information used in the Control was assimilated as well as Quality Controlled AIRS Version-5 temperature profiles, i.e., AIRS T(p) information was substituted for AIRS radiance information. The AIRS Version-5 temperature profiles were presented to the GSI analysis as rawinsonde profiles, assimilated down to a case-by-case appropriate pressure level p(sub best) determined using the Quality Control procedure. Version-5 also determines case-by-case, level-by-level error estimates of the temperature profiles, which were used as the uncertainty of each temperature measurement. These experiments using GEOS-5 have shown that forecasts

  20. A quantitative assessment of the relationship between precipitation deficits and air temperature variations

    NASA Astrophysics Data System (ADS)

    He, B.; Wang, H. L.; Wang, Q. F.; Di, Z. H.

    2015-06-01

    Previous studies have reported precipitation deficits related to temperature extremes. However, how and to what extent precipitation deficits affect surface air temperatures is still poorly understood. In this study, the relationship between precipitation deficits and surface temperatures was examined in China from 1960 to 2012 based on monthly temperature and precipitation records from 565 stations. Significant negative correlations were identified in each season, with the strongest relationships in the summer, indicating that higher temperatures usually accompanied water-deficient conditions and lower temperatures usually accompanied wet conditions. The examination of the correlations based on 30 year moving windows suggested that the interaction between the two variables has declined over the past three decades. Further investigation indicated a higher impact of extreme dry conditions on temperature than that of extreme wet conditions. In addition, a new simple index (Dry Temperature Index, DTI) was developed and used to quantitatively describe the relationship between water deficits and air temperature variations. We tested and compared the DTI in the coldest month (January) and the hottest month (July) of the year, station by station. In both months, the number of stations with a DThighI ≥ 50% was greater than those with a DThighI < 50%, indicating that a greater proportion of higher temperatures occurred during dry conditions. Based on the results, we conclude that water deficits in China are usually correlated to high temperatures but not to low temperatures.

  1. Geomagnetic activity related NOx enhancements and polar surface air temperature variability in a chemistry climate model: modulation of the NAM index

    NASA Astrophysics Data System (ADS)

    Baumgaertner, A. J. G.; Seppälä, A.; Jöckel, P.; Clilverd, M. A.

    2010-12-01

    The atmospheric chemistry general circulation model ECHAM5/MESSy is used to simulate polar surface air temperature effects of geomagnetic activity variations. A transient model simulation was performed for the years 1960-2004 and is shown to develop polar surface air temperature patterns that depend on geomagnetic activity strength, similar to previous studies. In order to eliminate influencing factors such as sea surface temperatures (SST) or UV variations, two nine-year long simulations were carried out, with strong and weak geomagnetic activity, respectively, while all other boundary conditions were held to year 2000 levels. Statistically significant temperature effects that were observed in previous reanalysis and model results are also obtained from this set of simulations, suggesting that such patterns are indeed related to geomagnetic activity. In the model, strong geomagnetic activity and the associated NOx enhancements lead to polar stratospheric ozone loss. Compared with the simulation with weak geomagnetic activity, the ozone loss causes a decrease in ozone radiative cooling and thus a temperature increase in the polar winter mesosphere. Similar to previous studies, a cooling is found below the stratopause, which other authors have attributed to a decrease in the mean meridional circulation. In the polar stratosphere this leads to a more stable vortex. A strong (weak) Northern Hemisphere vortex is known to be associated with a positive (negative) Northern Annular Mode (NAM) index; our simulations exhibit a positive NAM index for strong geomagnetic activity, and a negative NAM for weak geomagnetic activity. Such NAM anomalies have been shown to propagate to the surface, and this is also seen in the model simulations. NAM anomalies are known to lead to specific surface temperature anomalies: a positive NAM is associated with warmer than average northern Eurasia and colder than average eastern North Atlantic. This is also the case in our simulation. Our

  2. EMISSIONS OF AIR TOXICS FROM A SIMULATED CHARCOAL KILN EQUIPPED WITH AN AFTERBURNER

    EPA Science Inventory

    The report discusses emissions of air toxics from a simulated charcoal kiln equipped with an afterburner. A laboratory-scale simulator was constructed and tested to determine if it could be used to produce charcoal that was similar to that produced in Missouri-type charcoal kilns...

  3. Measuring centimeter-resolution air temperature profiles above land and water using fiber-optic Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Sigmund, Armin; Pfister, Lena; Olesch, Johannes; Thomas, Christoph K.

    2016-04-01

    The precise determination of near-surface air temperature profiles is of special importance for the characterization of airflows (e.g. cold air) and the quantification of sensible heat fluxes according to the flux-gradient similarity approach. In contrast to conventional multi-sensor techniques, measuring temperature profiles using fiber-optic Distributed Temperature Sensing (DTS) provides thousands of measurements referenced to a single calibration standard at much reduced costs. The aim of this work was to enhance the vertical resolution of Raman scatter DTS measurements up to the centimeter-scale using a novel approach for atmospheric applications: the optical fiber was helically coiled around a meshed fabric. In addition to testing the new fiber geometry, we quantified the measurement uncertainty and demonstrated the benefits of the enhanced-resolution profiles. The fiber-optic cable was coiled around a hollow column consisting of white reinforcing fabric supported by plexiglass rings every meter. Data from two columns of this type were collected for 47 days to measure air temperature vertically over 3.0 and 5.1 m over a gently inclined meadow and over and in a small lake, respectively. Both profiles had a vertical resolution of 1 cm in the lower section near the surface and 5 cm in the upper section with an along-fiber instrument-specific averaging of 1.0 m and a temporal resolution of 30 s. Measurement uncertainties, especially from conduction between reinforcing fabric and fiber-optic cable, were estimated by modeling the fiber temperature via a detailed energy balance approach. Air temperature, wind velocity and radiation components were needed as input data and measured separately. The temperature profiles revealed valuable details, especially in the lowest 1 m above surface. This was best demonstrated for nighttime observations when artefacts due to solar heating did not occur. For example, the dynamics of a cold air layer was detected in a clear night

  4. MODELING THE EFFECT OF WATER VAPOR ON THE INTERFACIAL BEHAVIOR OF HIGH-TEMPERATURE AIR IN CONTACT WITH Fe20Cr SURFACES

    SciTech Connect

    Chialvo, Ariel A; Brady, Michael P; Keiser, James R; Cole, David R

    2011-01-01

    The purpose of this communication is to provide an atomistic view, via molecular dynamic simulation, of the contrasting interfacial behavior between high temperature dry- and (10-40 vol%) wet-air in contact with stainless steels as represented by Fe20Cr. It was found that H2O preferentially adsorbs and displaces oxygen at the metal/fluid interface. Comparison of these findings with experimental studies reported in the literature is discussed. Keywords: Fe-Cr alloys, metal-fluid interfacial behavior, wet-air, molecular simulation

  5. Eleven years of ground-air temperature tracking over different land cover materials

    NASA Astrophysics Data System (ADS)

    Cermák, Vladimír; Dedecek, Petr; Bodri, Louise; Safanda, Jan; Kresl, Milan

    2015-04-01

    We have analyzed series of air, near surface and shallow ground temperatures under four different land covers, namely bare clayey soil, sand, grass and asphalt, collected between 2002 and 2013, monitored at the Geothermal Climate Change Observatory Sporilov. All obtained temperature series revealed a strong dependence of the subsurface thermal regime on the surface cover material. The ground "skin" temperatures are generally warmer than the surface air temperatures for all monitored surfaces; however they mutually differ significantly reflecting the nature of the land surface. Asphalt shows the highest temperatures, temperatures below the grassy surface are the lowest. A special interest was paid to the assessment of the "temperature offset", the difference between the surface ground temperature and the surface air temperature. Even when its instant value varies dramatically on both, daily and annual scale, by up to 30+ K, on a long time scale it is believed to be generally constant. The characteristic 2003-2013 mean offset values for the individual covers are following: asphalt 4.1 K, sand 1.6 K, clay 1.3 K and grass 0.2-0.3 K. All four surface covers revealed their daily and inter-annual cycles. Incident solar radiation is the primary variable in determining the amount of the temperature offset value and its time changes. A linear relationship between air-ground temperature differences and incident solar radiation was detected. The slope of the linear regression between both variables is clearly surface cover dependent. The greatest value of 3.3 K per 100 W.m-2 was found for asphalt, rates of 1.0 to 1.2 apply for bare soil and sand covers and negative slope of -0.44 K per 100 W.m-2 stands for grass, during the day or year the slope rates may vary extensively reflecting the periodic daily and/or annual cycle as well as the irregular instant deviations in solar radiation.

  6. Impact of aerosol on air temperature in Kuwait

    NASA Astrophysics Data System (ADS)

    Sabbah, I.

    2010-08-01

    This work uses MODIS aerosol optical thickness (AOT) data observed over Kuwait during the 7-year interval 2000-2007. The values of AOT and the Ångström wavelength exponent ( α) show a clear annual cycle. These data are categorized into two catalogues in terms of the values of the AOT of the 870 nm channel ( τ870). One catalogue (71 days) includes days with high values of AOT ( τ870 ≥ 0.75). The most probable "modal" value of α for these days is 0.52. The other catalogue (1162 days) consists of the background days with a modal value ~ 1.1 for the exponent α. This analysis is extended to include water vapor content (WVC), surface wind speed (V), visibility (Vis) and the diurnal temperature range (DTR). Chree's method of superposed-epoch analysis is applied to these parameters in order to compare the variation in the daily averages during days with high AOT values with respect to background days. The high values of AOT during the 71 days are positively correlated with aerosol size, near-surface winds and poor visibility. This concludes that the aerosol particles during these days were mostly dust. The mean daily value of the DTR (Δ T) and visibility reduced significantly during these days. This reduction on DTR is a direct result of increasing the atmospheric opacity due to the presence of dust.

  7. Numerical analysis of air-flow and temperature field in a passenger car compartment

    NASA Astrophysics Data System (ADS)

    Kamar, Haslinda Mohamed; Kamsah, Nazri; Mohammad Nor, Ahmad Miski

    2012-06-01

    This paper presents a numerical study on the temperature field inside a passenger's compartment of a Proton Wira saloon car using computational fluid dynamics (CFD) method. The main goal is to investigate the effects of different glazing types applied onto the front and rear windscreens of the car on the distribution of air-temperature inside the passenger compartment in the steady-state conditions. The air-flow condition in the passenger's compartment is also investigated. Fluent CFD software was used to develop a three-dimensional symmetrical model of the passenger's compartment. Simplified representations of the driver and one rear passenger were incorporated into the CFD model of the passenger's compartment. Two types of glazing were considered namely clear insulated laminated tint (CIL) with a shading coefficient of 0.78 and green insulated laminate tint (GIL) with a shading coefficient of 0.5. Results of the CFD analysis were compared with those obtained when the windscreens are made up of clear glass having a shading coefficient of 0.86. Results of the CFD analysis show that for a given glazing material, the temperature of the air around the driver is slightly lower than the air around the rear passenger. Also, the use of GIL glazing material on both the front and rear windscreens significantly reduces the air temperature inside the passenger's compartment of the car. This contributes to a better thermal comfort condition to the occupants. Swirling air flow condition occurs in the passenger compartment. The air-flow intensity and velocity are higher along the side wall of the passenger's compartment compared to that along the middle section of the compartment. It was also found that the use of glazing materials on both the front and rear windscreen has no significant effects on the air-flow condition inside the passenger's compartment of the car.

  8. Characterization of AIRS temperature and water vapor measurement capability using correlative observations

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Eldering, Annmarie; Lee, Sung-Yung

    2005-01-01

    In this presentation we address several fundamental issues in the measurement of temperature and water vapor by AIRS: accuracy, precision, vertical resolution and biases as a function of cloud amount. We use two correlative data sources. First we compare AIRS total water vapor with that from the Advanced microwave Sounding Radiometer for EOS (AMSR-E) instrument, also onboard the Aqua spacecraft. AMSRE uses a mature methodology with a heritage including the operational Special Sensor Microwave Imager (SSM/I) instruments. AIRS and AMSR-E observations are collocated and simultaneous, providing a very large data set for comparison: about 200,000 over-ocean matches daily. We show small cloud-dependent biases between AIRS and AMSR-E total water vapor for several oceanic regions. Our second correlative data source is several hundred dedicated radiosondes launched during AIRS overpasses.

  9. The Impacts of a 2-Degree Rise in Global Temperatures upon Gas-Phase Air Pollutants in Europe

    NASA Astrophysics Data System (ADS)

    Watson, Laura; Josse, Béatrice; Marecal, Virginie; Lacressonnière, Gwendoline; Vautard, Robert; Gauss, Michael; Engardt, Magnuz; Nyiri, Agnes; Siour, Guillaume

    2014-05-01

    The 15th session of the Conference of Parties (COP 15) in 2009 ratified the Copenhagen Accord, which "recognises the scientific view that" global temperature rise should be held below 2 degrees C above pre-industrial levels in order to limit the impacts of climate change. Due to the fact that a 2-degree limit has been frequently referred to by policy makers in the context of the Copenhagen Accord and many other high-level policy statements, it is important that the impacts of this 2-degree increase in temperature are adequately analysed. To this end, the European Union sponsored the project IMPACT2C, which uses a multi-disciplinary international team to assess a wide variety of impacts of a 2-degree rise in global temperatures. For example, this future increase in temperature is expected to have a significant influence upon meteorological conditions such as temperature, precipitation, and wind direction and intensity; which will in turn affect the production, deposition, and distribution of air pollutants. For the first part of the air quality analysis within the IMPACT2C project, the impact of meteorological forcings on gas phase air pollutants over Europe was studied using four offline atmospheric chemistry transport models. Two sets of meteorological forcings were used for each model: reanalysis of past observation data and global climate model output. Anthropogenic emissions of ozone precursors for the year 2005 were used for all simulations in order to isolate the impact of meteorology and assess the robustness of the results across the different models. The differences between the simulations that use reanalysis of past observation data and the simulations that use global climate model output show how global climate models modify climate hindcasts by boundary conditions inputs: information that is necessary in order to interpret simulations of future climate. The baseline results were assessed by comparison with AirBase (Version 7) measurement data, and were

  10. Laser-driven hypersonic air-breathing propulsion simulator

    NASA Technical Reports Server (NTRS)

    Joshi, Prakash B.; Lo, Edmond Y.; Pugh, Evan R.

    1992-01-01

    A feasibility study is presented of simulating airbreathing propulsion on small scale hypersonic models using laser energy. The laser heat addition scheme allows simultaneous inlet and exhaust flows during wind tunnel testing of models with scramjet models. The proposed propulsion simulation concept has extended the Kantrowitz (1974) idea to propulsive wind tunnel models of hypersonic aircraft. Critical issues in aeropropulsive testing of models based on a ramjet power plant are addressed which include transfer of the correct amount of energy to the flowing gas, efficient absorption of laser energy into the gas, and test performance under tunnel reservoir conditions and at reasonable Reynolds numbers.

  11. Short-term effects of air temperature on mortality and effect modification by air pollution in three cities of Bavaria, Germany: A time-series analysis

    EPA Science Inventory

    Background: Air temperature has been shown to be associated with mortality; however, only very few studies have been conducted in Germany. This study examined the association between daily air temperature and cause-specific mortality in Bavaria, Southern Germany. Moreover, we inv...

  12. Numerical simulation of high pressure release and dispersion of hydrogen into air with real gas model

    NASA Astrophysics Data System (ADS)

    Khaksarfard, R.; Kameshki, M. R.; Paraschivoiu, M.

    2010-06-01

    Hydrogen is a renewable and clean source of energy, and it is a good replacement for the current fossil fuels. Nevertheless, hydrogen should be stored in high-pressure reservoirs to have sufficient energy. An in-house code is developed to numerically simulate the release of hydrogen from a high-pressure tank into ambient air with more accuracy. Real gas models are used to simulate the flow since high-pressure hydrogen deviates from ideal gas law. Beattie-Bridgeman and Abel Noble equations are applied as real gas equation of state. A transport equation is added to the code to calculate the concentration of the hydrogen-air mixture after release. The uniqueness of the code is to simulate hydrogen in air release with the real gas model. Initial tank pressures of up to 70 MPa are simulated.

  13. Comparison of exposure estimation methods for air pollutants: ambient monitoring data and regional air quality simulation.

    PubMed

    Bravo, Mercedes A; Fuentes, Montserrat; Zhang, Yang; Burr, Michael J; Bell, Michelle L

    2012-07-01

    Air quality modeling could potentially improve exposure estimates for use in epidemiological studies. We investigated this application of air quality modeling by estimating location-specific (point) and spatially-aggregated (county level) exposure concentrations of particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM(2.5)) and ozone (O(3)) for the eastern U.S. in 2002 using the Community Multi-scale Air Quality (CMAQ) modeling system and a traditional approach using ambient monitors. The monitoring approach produced estimates for 370 and 454 counties for PM(2.5) and O(3), respectively. Modeled estimates included 1861 counties, covering 50% more population. The population uncovered by monitors differed from those near monitors (e.g., urbanicity, race, education, age, unemployment, income, modeled pollutant levels). CMAQ overestimated O(3) (annual normalized mean bias=4.30%), while modeled PM(2.5) had an annual normalized mean bias of -2.09%, although bias varied seasonally, from 32% in November to -27% in July. Epidemiology may benefit from air quality modeling, with improved spatial and temporal resolution and the ability to study populations far from monitors that may differ from those near monitors. However, model performance varied by measure of performance, season, and location. Thus, the appropriateness of using such modeled exposures in health studies depends on the pollutant and metric of concern, acceptable level of uncertainty, population of interest, study design, and other factors. PMID:22579357

  14. Comparison of exposure estimation methods for air pollutants: Ambient monitoring data and regional air quality simulation

    PubMed Central

    Bravo, Mercedes A.; Fuentes, Montserrat; Zhang, Yang; Burr, Michael J.; Bell, Michelle L.

    2012-01-01

    Air quality modeling could potentially improve exposure estimates for use in epidemiological studies. We investigated this application of air quality modeling by estimating location-specific (point) and spatially-aggregated (county level) exposure concentrations of particulate matter with an aerodynamic diameter less than or equal to 2.5 µm (PM2.5) and ozone (O3) for the eastern U.S. in 2002 using the Community Multi-scale Air Quality (CMAQ) modeling system and a traditional approach using ambient monitors. The monitoring approach produced estimates for 370 and 454 counties for PM2.5 and O3, respectively. Modeled estimates included 1861 counties, covering 50% more population. The population uncovered by monitors differed from those near monitors (e.g., urbanicity, race, education, age, unemployment, income, modeled pollutant levels). CMAQ overestimated O3 (annual normalized mean bias = 4.30%), while modeled PM2.5 had an annual normalized mean bias of −2.09%, although bias varied seasonally, from 32% in November to −27% in July. Epidemiology may benefit from air quality modeling, with improved spatial and temporal resolution and the ability to study populations far from monitors that may differ from those near monitors. However, model performance varied by measure of performance, season, and location. Thus, the appropriateness of using such modeled exposures in health studies depends on the pollutant and metric of concern, acceptable level of uncertainty, population of interest, study design, and other factors. PMID:22579357

  15. The comparative performance of an aviation engine at normal and high inlet air temperatures

    NASA Technical Reports Server (NTRS)

    Gardiner, Arthur W; Schey, Oscar W

    1928-01-01

    This report presents some results obtained during an investigation to determine the effect of high inlet